WorldWideScience

Sample records for cenozoic climate trends

  1. Trends, Rhythms, and Aberrations in Global Climate during the Cenozoic: The Interplay between Tectonic and Orbital forcing (Milutin Milankovic Medal Lecture)

    Science.gov (United States)

    Zachos, James C.

    2016-04-01

    Prior to the mid-nineties much of our understanding of early Neogene and Paleogene climate was based on relatively low-resolution reconstructions. As a consequence, under-sampled periodic climate variability appeared as noise in global records (i.e., stacks), limiting our ability to fully evaluate mechanisms of past climate change. Efforts to address this limitation began in earnest with Ocean Drilling Program Leg 154, one of the first to successfully recover high-quality stratigraphically complete and relatively expanded successions of Paleogene pelagic sediments, allowing for astronomical tuning and the development of detailed paleoclimatic records extending back into the Oligocene. The strategies implemented during this Leg to locate, recover, and tune Paleogene sequences were adapted by subsequent ODP/IODP expeditions, ultimately contributing to the development of high-resolution astronomically-tuned climate records extending back to the Cretaceous. The collective contributions of these expeditions provided the necessary framework for characterizing climate variability on orbital time scales throughout the Cenozoic, including the major transitions and aberrations, the Oligocene-Miocene (O/M), Eocene-Oligocene Transition (EOT), and the Paleocene-Eocene Thermal Maximum (PETM). In this presentation I will review the most recent advances in reconstructing past climates on orbital time scales, and how these advances are altering our understanding of the triggering mechanisms for these major climate transitions, and discuss how the interplay between tectonic processes and orbital forcing as well as physical and geochemical feedbacks contributed to drive the more rapid and extreme aberrations.

  2. Cenozoic planktonic marine diatom diversity and correlation to climate change.

    Science.gov (United States)

    Lazarus, David; Barron, John; Renaudie, Johan; Diver, Patrick; Türke, Andreas

    2014-01-01

    Marine planktonic diatoms export carbon to the deep ocean, playing a key role in the global carbon cycle. Although commonly thought to have diversified over the Cenozoic as global oceans cooled, only two conflicting quantitative reconstructions exist, both from the Neptune deep-sea microfossil occurrences database. Total diversity shows Cenozoic increase but is sample size biased; conventional subsampling shows little net change. We calculate diversity from a separately compiled new diatom species range catalog, and recalculate Neptune subsampled-in-bin diversity using new methods to correct for increasing Cenozoic geographic endemism and decreasing Cenozoic evenness. We find coherent, substantial Cenozoic diversification in both datasets. Many living cold water species, including species important for export productivity, originate only in the latest Miocene or younger. We make a first quantitative comparison of diatom diversity to the global Cenozoic benthic ∂(18)O (climate) and carbon cycle records (∂(13)C, and 20-0 Ma pCO2). Warmer climates are strongly correlated with lower diatom diversity (raw: rho = .92, p.9, detrended r>.6, all prisk of extinction in future warm oceans, with an unknown but potentially substantial negative impact on the ocean biologic pump and oceanic carbon sequestration. We cannot however extrapolate our my-scale correlations with generic climate proxies to anthropogenic time-scales of warming without additional species-specific information on proximate ecologic controls. PMID:24465441

  3. Cenozoic planktonic marine diatom diversity and correlation to climate change.

    Directory of Open Access Journals (Sweden)

    David Lazarus

    Full Text Available Marine planktonic diatoms export carbon to the deep ocean, playing a key role in the global carbon cycle. Although commonly thought to have diversified over the Cenozoic as global oceans cooled, only two conflicting quantitative reconstructions exist, both from the Neptune deep-sea microfossil occurrences database. Total diversity shows Cenozoic increase but is sample size biased; conventional subsampling shows little net change. We calculate diversity from a separately compiled new diatom species range catalog, and recalculate Neptune subsampled-in-bin diversity using new methods to correct for increasing Cenozoic geographic endemism and decreasing Cenozoic evenness. We find coherent, substantial Cenozoic diversification in both datasets. Many living cold water species, including species important for export productivity, originate only in the latest Miocene or younger. We make a first quantitative comparison of diatom diversity to the global Cenozoic benthic ∂(18O (climate and carbon cycle records (∂(13C, and 20-0 Ma pCO2. Warmer climates are strongly correlated with lower diatom diversity (raw: rho = .92, p.9, detrended r>.6, all p<.001, but only weakly over the earlier Cenozoic, suggesting increasingly strong linkage of diatom and climate evolution in the Neogene. Our results suggest that many living marine planktonic diatom species may be at risk of extinction in future warm oceans, with an unknown but potentially substantial negative impact on the ocean biologic pump and oceanic carbon sequestration. We cannot however extrapolate our my-scale correlations with generic climate proxies to anthropogenic time-scales of warming without additional species-specific information on proximate ecologic controls.

  4. Present-day climatic equivalents of European Cenozoic climates

    Science.gov (United States)

    Utescher, Torsten; Mosbrugger, Volker; Ivanov, Dimiter; Dilcher, David L.

    2009-07-01

    Recently, continental climate evolution in Central Europe over the last 45 Ma has been reconstructed from the palaeobotanical record using a Nearest Living Relative methodology (Coexistence Approach; CA). The reconstructed climate curves document in detail the transition from almost tropical conditions in the Mid-Eocene to a temperate climate at the Pliocene/Pleistocene transition. The observed climatic shifts are primarily expressed as non-proportional changes of the different variables taken into account. In the present study a published palaeoclimate data set for a total of 42 macrofloras complemented by new calculations is used as base to analyse the climatic space in which a fossil flora existed. To define these spaces CA intervals calculated for 3 temperature (mean annual temperature, cold and warm month mean) and 3 precipitation variables (mean annual precipitation, mean monthly precipitation of the driest and of the wettest month) are combined. Using a global gridded climatology (10' resolution), this climate space is then utilized to identify Recent climate analogues with respect to the variables regarded. For 18 macrofloras climatic analogue regions with respect to 6 variables are identified on the globe. For 16 macrofloras, analogues exist when three temperature parameters and mean annual precipitation are regarded. No Recent equivalents are found in 8 cases. This corroborates the assumption of the temporary existence of non-analogue climates in the Cenozoic. As shown by multivariate statistics the observed anomalies with respect to present-day conditions basically refer to high winter temperatures. Deploying a GIS, the Recent climate analogues can be presented as sets of grid cells for each flora that can be mapped on a globe. Once identified, these regions can be merged with adequate thematic layers to assess additional proxy data for the palaeofloras. To exemplify the procedure Koeppen climate type, numbers of days with ground frost, as well as

  5. Disentangling Topographic and Climatic Change during the Late Cretaceous and Cenozoic in the Western US Cordillera

    Science.gov (United States)

    Snell, K. E.; Eiler, J. M.; Wernicke, B. P.; Peppe, D. J.; Fox, D. L.; Fetrow, A. C.; Passey, B. H.

    2014-12-01

    A diverse suite of tectonic and climatic drivers influenced the topographic evolution of the western USA Cordillera. Despite years of study, considerable uncertainty remains about fundamentals of this evolution, such as the timing and magnitude of maximum average elevations for the different physiographic provinces; the drivers and topographic effects of different episodes of extension during the Cenozoic; and the relative relief of peaks and intermontane basins within the Cordillera at different times and in different places. Numerous tectonic models have been developed to explain the evolution of the Cordillera, and understanding these details is key for distinguishing between these different models. In addition, the topographic changes in the Cordillera have important implications for regional and local climate of the western US at different times in the past, and may drive important differences in local climatic responses to global climate changes through the Cenozoic. The majority of the tools that currently exist for quantitatively reconstructing changes in topography through time and space rely on paleoclimate proxy data. Thus it is also important to be able to disentangle climatic change from elevation change in terrestrial paleoclimate records. To address some of these outstanding questions, we have generated and compiled paleotemperature estimates from the Late Cretaceous through the Miocene of the western US. In this presentation, we will focus on the latest installment of the project, which utilizes Oligocene paleotemperature records from central Utah and South Dakota and Miocene-Holocene paleotemperature records from Kansas. The data are dominantly composed of mean annual temperature estimates from leaf margin analysis and summer temperature estimates from carbonate clumped isotope thermometry. We will discuss how these data compare to temperature data from the Paleogene from the western US, what general trends exist within all the data and how these

  6. Cenozoic vegetation, climate changes and hominid evolution in tropical Africa

    Science.gov (United States)

    Bonnefille, Raymonde

    2010-07-01

    This paper reviews information on past vegetation of tropical Africa during the Cenozoic, focused upon the last 10 Ma, a time spanning hominid record in Central and East Africa. Summary of palaeobotanical data collected at terrestrial sites are compared with new results on the long term evolution of the continental vegetation zones documented from marine pollen record of two deep sea cores recovered from the Atlantic and Indian Oceans. Section 2 includes a summary of modern distribution of vegetation belts in the African continent and a synthesis of the results of both macrobotanical (fossil wood, leaves and fruits) and microbotanical (mainly pollen) studies presented according to time scale and geographical location. The main features emphasized by the palaeobotanical results are 1) seasonal vegetation and climate documented as soon as the Eocene in Tanzania 2) well diversified forests existing in northern West Ethiopia during the Oligocene 3) high temporal and spatial variabilities of forests composition during the Miocene when deciduous Legume woodland was documented in Ethiopia whereas wetter evergreen forests existed in Western Kenya 4) lack of evidence for an evergreen forest belt, continuous from Western Congo to East Africa. Section 3 presents new original pollen data recovered from a long core in the Gulf of Aden documenting large scale past vegetation changes in East Africa during the last 11 Ma. These results are discussed in comparison with a summarized long pollen sequence previously published from a marine core offshore the Niger delta. This comparison illustrates variations in geographical distribution of large vegetation zone at the continental scale, through time. In Section 4, vegetation changes registered during the last 10 Ma are discussed in relation with the results of isotopic studies and an updated presentation of hominids evolution in Africa. Several changes are shown in the marine records. An expansion of savanna/grassland is shown at 10

  7. Climate vs. tectonic induced variations in Cenozoic sediment supply from western Scandinavia

    DEFF Research Database (Denmark)

    Gołędowski, Bartosz; Nielsen, S.B.; Clausen, O.R.

    on a particular rudimentary understanding of the Davisian cyclic landscape evolution model, which does not consider the occurrence of flexural isostasy or glacial buzzsaw processes. Observations of small scale sedimentary structures of ambiguous origin and activity of salt-related structures is not evidence...... for this hypothesised large-scale uplift [13]. Furthermore, there is little if any evidence for onshore Cenozoic tectonic activity, which is also not constrained by fission track dating [2, 14-20]. Climate variations during Cenozoic times are constrained by oxygen isotope values in benthic foraminifera [21...... by extensive vegetation cover as little bedrock is exposed and soils are well-developed. In case of climate cooling the tree limit lowers, exposing more bedrock for erosion. Furthermore, the erosional regime changes dramatically in the presence of alpine glaciers and cirques and when periglacial processes...

  8. Climate vs. tectonic induced variations in Cenozoic sediment supply from western Scandinavia

    DEFF Research Database (Denmark)

    Gołędowski, Bartosz; Nielsen, S.B.; Clausen, O.R.

    , faulting), tectonic disturbance related to ocean opening could be responsible for deposition of thick Paleocene wedges along the western coast of Norway. During subsequent Cenozoic periods domal structures in the Norwegian shelf are a proof for mild and protracted compression. However, depositional......) changed the erosional regime in western Scandinavia from fluvial (inefficient in tectonically stable settings, almost regardless of the amount of precipitation) to glacial. Glacial erosion is much more effective and is apparently able to outpace tectonic processes responsible for development of high...... topography. Therefore, a hypothesis of climate control on erosion and deposition during the Cenozoic history of western Scandinavia and adjacent sedimentary basins emerges. This theory is further supported by higher sediment input and pronounced progradation patterns of the Molo Formation (deposited during...

  9. Antarctic Cenozoic climate history from sedimentary records: ANDRILL and beyond.

    Science.gov (United States)

    McKay, R M; Barrett, P J; Levy, R S; Naish, T R; Golledge, N R; Pyne, A

    2016-01-28

    Mounting evidence from models and geological data implies that the Antarctic Ice Sheet may behave in an unstable manner and retreat rapidly in response to a warming climate, which is a key factor motivating efforts to improve estimates of Antarctic ice volume contributions to future sea-level rise. Here, we review Antarctic cooling history since peak temperatures of the Middle Eocene Climatic Optimum (approx. 50 Ma) to provide a framework for future initiatives to recover sediment cores from subglacial lakes and sedimentary basins in Antarctica's continental interior. While the existing inventory of cores has yielded important insights into the biotic and climatic evolution of Antarctica, strata have numerous and often lengthy time breaks, providing a framework of 'snapshots' through time. Further cores, and more work on existing cores, are needed to reconcile Antarctic records with the more continuous 'far-field' records documenting the evolution of global ice volume and deep-sea temperature. To achieve this, we argue for an integrated portfolio of drilling and coring missions that encompasses existing methodologies using ship- and sea-ice-/ice-shelf-based drilling platforms as well as recently developed seafloor-based drilling and subglacial access systems. We conclude by reviewing key technological issues that will need to be overcome. PMID:26667911

  10. A chilling perspective on Greenland's early Cenozoic climate from coupled Hf-Nd isotopes

    Science.gov (United States)

    Scher, H. D.; Bizimis, M.; Buckley, W. P., Jr.; Duggan, B.; Bohaty, S. M.; Wilson, P. A.

    2015-12-01

    The prevailing view of northern hemisphere glaciation has been of ice sheets forming on Greenland after 2.7 Ma, with iceberg rafting as early as 15 Ma. This view is incompatible with recent results from global climate/ice sheet models that predict northern hemisphere glaciation only after CO2 falls below ~280 ppmv (occurring at 25 Ma) and with recent sediment evidence for Arctic iceberg rafting as early as the middle Eocene. However, the amount of northern hemisphere ice represented by these sediments is ambiguous and global ice budget calculations for the early Cenozoic are controversial. Here we use coupled Hf-Nd isotopes of oxyhydroxides in sediments from the upper Eocene to lower Oligocene section in ODP Site U1411 (Newfoundland Ridge) to determine when the circum-North Atlantic came under the influence of a mechanical weathering regime. Leached oxyhydroxide Hf-Nd isotopes are an indicator of weathering intensity because mechanical weathering by ice sheets mobilizes the zircon-bound Hf reservoir in the crust, which has extreme unradiogenic eHf values. Chemical weathering produces a distinct seawater array on Hf-Nd diagrams, while seawater exposed to the products of mechanical weathering plot on divergent arrays closer to the Terrestrial Array. Hf-Nd isotopes of Site U1411 leachates are grouped in a near vertical trend between the seawater and terrestrial global reference arrays. Within this group there are four distinct arrays that can be delineated by age. Samples that are late Eocene in age fall along an array that is slightly divergent from the seawater array. The aspect of the Hf-Nd isotope data changes permanently after the first step of the EOT, falling along arrays that are systematically offset in the direction of the terrestrial arrays. The steepest array, most proximal to the terrestrial array, is comprised of samples deposited between 33.7 and 32.2 Ma. These results indicate a circum-North Atlantic weathering regime appeared in the earliest Oligocene.

  11. Climate Trends and Impacts in China

    OpenAIRE

    Sall, Chris

    2013-01-01

    This discussion paper summarizes observed and projected trends in extreme weather events, present-day climate variability, and future climate change and their impacts on China's different regions. Findings are presented from China's national assessment report on climate change (2007) and second national assessment report on climate change (2011) as well as other studies by Chinese and inte...

  12. Vital effects in coccolith calcite: Cenozoic climate-pCO2 drove the diversity of carbon acquisition strategies in coccolithophores?

    Science.gov (United States)

    Bolton, Clara T.; Stoll, Heather M.; Mendez-Vicente, Ana

    2012-12-01

    Coccoliths, calcite plates produced by the marine phytoplankton coccolithophores, have previously shown a large array of carbon and oxygen stable isotope fractionations (termed "vital effects"), correlated to cell size and hypothesized to reflect the varying importance of active carbon acquisition strategies. Culture studies show a reduced range of vital effects between large and small coccolithophores under high CO2, consistent with previous observations of a smaller range of interspecific vital effects in Paleocene coccoliths. We present new fossil data examining coccolithophore vital effects over three key Cenozoic intervals reflecting changing climate and atmospheric partial pressure of CO2 (pCO2). Oxygen and carbon stable isotopes of size-separated coccolith fractions dominated by different species from well preserved Paleocene-Eocene thermal maximum (PETM, ˜56 Ma) samples show reduced interspecific differences within the greenhouse boundary conditions of the PETM. Conversely, isotope data from the Plio-Pleistocene transition (PPT; 3.5-2 Ma) and the last glacial maximum (LGM; ˜22 ka) show persistent vital effects of ˜2‰. PPT and LGM data show a clear positive trend between coccolith (cell) size and isotopic enrichment in coccolith carbonate, as seen in laboratory cultures. On geological timescales, the degree of expression of vital effects in coccoliths appears to be insensitive topCO2 changes over the range ˜350 ppm (Pliocene) to ˜180 ppm (LGM). The modern array of coccolith vital effects arose after the PETM but before the late Pliocene and may reflect the operation of more diverse carbon acquisition strategies in coccolithophores in response to decreasing Cenozoic pCO2.

  13. Permian to late Cenozoic evolution of northern Patagonia: Main tectonic events, magmatic activity, and depositional trends

    Science.gov (United States)

    Uliana, M. A.; Biddle, K. T.

    The late Paleozoic to late Cenozoic evolution of northern Patagonia was influenced significantly by events that occurred while the area was part of the South American sector of Gondwanaland. Late Paleozoic to Middle Triassic subduction along the edge of the supercontinent formed a broad convergent-margin system that is the underpinning of northern Patagonia. Deformation (Gondwanidian orogeny) associated with the subduction is recognized in both the forearc and the convergent backarc areas. Regional extension, accompanied by bimodal volcanism, began in the Late Triassic and led to the formation of a number of north-northwest trending rift basins in Patagonia, which generally followed the Gondwanidian basement grain. Continued extension in the Jurassic and Early Cretaceous led to the opening of the Rocas Verdes marginal basin in southern Chile and, ultimately, to the opening of the South Atlantic Ocean. Once oceanic crust began to form, faulting and volcanism declined in Patagonia. During the late Early Cretaceous to the Late Cretaceous, sags over the rift basins coalesced to form a broad backarc basin behind the volcanic arc to the west. These sags are suggestive of thermally driven subsidence. Subsidence of the evolving Atlantic margin allowed extensive marine transgressions to take place from the east. The stratigraphic record of northern Patagonia reflects these events. The upper Paleozoic to upper Mesozoic sedimentary sequences were deposited in basins directly associated with convergent activity along the margin of Gondwanaland or in rift basins created during its breakup. Even though the Tertiary evolution of Patagonia was dominated by events along the western margin of South America, the patterns of sediment transport, thickness, and general shoreline position were still influenced by the locations of the Mesozoic rifts formed during the breakup of Gondwanaland.

  14. Investigating Cenozoic climate change in tectonically active regions with a high-resolution atmospheric general circulation model (ECHAM5)

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    Mutz, Sebastian; Ehlers, Todd; Li, Jingmin; Werner, Martin; Stepanek, Christian; Lohmann, Gerrit

    2016-04-01

    Studies of Cenozoic palaeo-climates contribute to our understanding of contemporary climate change by providing insight into analogues such as the Pliocene (PLIO), and by evaluation of GCM (General Circulation Models) performance using the Mid-Holocene (MH) and the Last Glacial Maximum (LGM). Furthermore, climate is a factor to be considered in the evolution of ecology, landscapes and mountains, and in the reconstruction of erosion histories. In this study, we use high-resolution (T159) ECHAM5 simulations to investigate pre-industrial (PI) and the the above mentioned palaeo-climates for four tectonically active regions: Alaska (St. Elias Range), the US Northwest Pacific (Cascade Range), western South America (Andes) and parts of Asia (Himalaya-Tibet). The PI climate simulation is an AMIP (Atmospheric Model Intercomparison Project) style ECHAM5 experiment, whereas MH and LGM simulation are based on simulations conducted at the Alfred Wegner Institute, Bremerhaven. Sea surface boundary conditions for MH were taken from coupled atmosphere-ocean model simulations (Wei and Lohmann, 2012; Zhang et al, 2013) and sea surface temperatures and sea ice concentration for the LGM are based on GLAMAP project reconstructions (Schäfer-Neth and Paul, 2003). Boundary conditions for the PLIO simulation are taken from the PRISM (Pliocene Research, Interpretation and Synoptic Mapping) project and the employed PLIO vegetation boundary condition is created by means of the transfer procedure for the PRISM vegetation reconstruction to the JSBACH plant functional types as described by Stepanek and Lohmann (2012). For each of the investigated areas and time slices, the regional simulated climates are described by means of cluster analyses based on the variability of precipitation, 2m air temperature and the intra-annual amplitude of the values. Results indicate the largest differences to a PI climate are observed for LGM and PLIO climates in the form of widespread cooling and warming

  15. Cenozoic Mammals and Climate Change: The Contrast between Coarse-Scale versus High-Resolution Studies Explained by Species Sorting

    OpenAIRE

    Donald Prothero

    2012-01-01

    Many paleontologists have noticed the broadly similar patterns between the changes in Cenozoic mammalian diversity and taxonomic dominance and climate changes. Yet detailed studies of fossil population samples with fine-scale temporal resolution during episodes of climate change like the Eocene-Oligocene transition in the White River Group, and the late Pleistocene at Rancho La Brea tar pits, demonstrates that most fossil mammal species are static and show no significant microevolutionary res...

  16. Book Review: Late Cenozoic Climate Change in Asia: Loess, Monsoon and Monsoon-arid Environment Evolution

    Science.gov (United States)

    Clemens, Steven C.

    2015-01-01

    Loess-Paleosol deposits drape >500,000 km2 of eastern China, spanning environments from the humid, monsoon-influenced regions near the coast to the arid, westerlies-dominated regions inland. Sections, up to hundreds of meters thick, are exposed in deeply incised river valleys and can be accessed as well by drilling. Combined, the high sedimentation rates and extensive geographic coverage make these sections unique among global terrestrial sediment archives. The Chinese loess-paleosol sequences, and the arid interior regions to the northwest, record diverse aspects of geologic and environmental change ranging from the tectonic evolution of the Tibetan Plateau (106 year time scale) through glacial-interglacial scale changes in global ice volume and greenhouse gasses (105 year time scale) on down through the orbital (104 years) to millennial and centennial scale events (103-102 year) relevant to the underpinnings of human interactions with changing environmental pressures. 'Late Cenozoic Climate Chang in Asia: Loess, Monsoon and Monsoon-arid Environment Evolution' is a timely contribution that synthesizes findings derived from the extensive work in these areas, places the findings in the broader context of global climate change and helps to define avenues for future research.

  17. Cenozoic Mammals and Climate Change: The Contrast between Coarse-Scale versus High-Resolution Studies Explained by Species Sorting

    Directory of Open Access Journals (Sweden)

    Donald Prothero

    2012-04-01

    Full Text Available Many paleontologists have noticed the broadly similar patterns between the changes in Cenozoic mammalian diversity and taxonomic dominance and climate changes. Yet detailed studies of fossil population samples with fine-scale temporal resolution during episodes of climate change like the Eocene-Oligocene transition in the White River Group, and the late Pleistocene at Rancho La Brea tar pits, demonstrates that most fossil mammal species are static and show no significant microevolutionary response to major climate changes. This mismatch between patterns seems best explained by species sorting. As the punctuated equilibrium model demonstrated, over long time spans most fossil species are stable and do not respond to climate change. Instead, change occurs at the next hierarchical level, with species sorting adding and subtracting to the total diversity pattern revealed by coarse-scale taxon counting, apparently responding to longer-term changes in climate as revealed by proxies like the oxygen isotope record.

  18. Paleo-climate evolution in China and its control on the metallization of sandstone type uranium deposit of Meso-Cenozoic basins

    International Nuclear Information System (INIS)

    This paper analyzed the climate evolution of China in Meso-cenozoic and indicated that climate in Early Jurassic, Middle Jurassic, Early Cretaceous and Late Cretaceous was favorite for the forming of uranium deposit produced corresponding uranium bearing strata. The paper have set up the system of paleo-climate evolution in China and discussed the control role of modern climate on uranium metallization in the basins. (authors)

  19. A climate trend analysis of Uganda

    Science.gov (United States)

    Funk, Christopher C.; Rowland, Jim; Eilerts, Gary; White, Libby

    2012-01-01

    This brief report, drawing from a multi-year effort by the U.S. Agency for International Development (USAID) Famine Early Warning Systems Network (FEWS NET), identifies observed changes in rainfall and temperature in Uganda, based on an analysis of a quality-controlled, long time series of station observations throughout Uganda. Extending recent trends forward, it also provides a current and near-future context for understanding the actual nature of climate change impacts in the country, and a basis for identifying climate adaptations that may protect and improve the country's food security.

  20. A first-order global model of Late Cenozoic climatic change: Orbital forcing as a pacemaker of the ice ages

    Science.gov (United States)

    Saltzman, Barry

    1992-01-01

    The development of a theory of the evolution of the climate of the earth over millions of years can be subdivided into three fundamental, nested, problems: (1) to establish by equilibrium climate models (e.g., general circulation models) the diagnostic relations, valid at any time, between the fast-response climate variables (i.e., the 'weather statistics') and both the prescribed external radiative forcing and the prescribed distribution of the slow response variables (e.g., the ice sheets and shelves, the deep ocean state, and the atmospheric CO2 concentration); (2) to construct, by an essentially inductive process, a model of the time-dependent evolution of the slow-response climatic variables over time scales longer than the damping times of these variables but shorter than the time scale of tectonic changes in the boundary conditions (e.g., altered geography and elevation of the continents, slow outgassing, and weathering) and ultra-slow astronomical changes such as in the solar radiative output; and (3) to determine the nature of these ultra-slow processes and their effects on the evolution of the equilibrium state of the climatic system about which the above time-dependent variations occur. All three problems are discussed in the context of the theory of the Quaternary climate, which will be incomplete unless it is embedded in a more general theory for the fuller Cenozoic that can accommodate the onset of the ice-age fluctuations. We construct a simple mathematical model for the Late Cenozoic climatic changes based on the hypothesis that forced and free variations of the concentration of atmospheric greenhouse gases (notably CO2), coupled with changes in the deep ocean state and ice mass, under the additional 'pacemaking' influence of earth-orbital forcing, are primary determinants of the climate state over this period. Our goal is to illustrate how a single model governing both very long term variations and higher frequency oscillatory variations in the

  1. Late Cenozoic climate and the phylogenetic structure of regional conifer floras worldwide

    NARCIS (Netherlands)

    W.L. Eiserhardt; F. Borchsenius; B. Sandel; W.D. Kissling; J.-C. Svenning

    2015-01-01

    Aim Using conifers as a model system, we aim to test four hypotheses. H1: the processes that shape the phylogenetic structure of regional species assemblages depend on climate. H2: apparent effects of current climate can be equally well explained by past climate. H3: strong Quaternary climate oscill

  2. A climate trend analysis of Ethiopia

    Science.gov (United States)

    Funk, Christopher C.; Rowland, Jim; Eilerts, Gary; Kebebe, Emebet; Biru, Nigist; White, Libby; Galu, Gideon

    2012-01-01

    This brief report, drawing from a multi-year effort by the U.S. Agency for International Development (USAID) Famine Early Warning Systems Network (FEWS NET), examines recent trends in March-June, June-September, and March-September rainfall and temperature, identifying significant reductions in rainfall and increases in temperature over time in many areas of Ethiopia. Conclusions: * Spring and summer rains in parts of Ethiopia have declined by 15-20 percent since the mid-1970s. * Substantial warming across the entire country has exacerbated the dryness.* An important pattern of observed existing rainfall declines coincides with heavily populated areas of the Rift Valley in south-central Ethiopia, and is likely already adversely affecting crop yields and pasture conditions. * Rapid population growth and the expansion of farming and pastoralism under a drier, warmer climate regime could dramatically increase the number of at-risk people in Ethiopia during the next 20 years.* Many areas of Ethiopia will maintain moist climate conditions, and agricultural development in these areas could help offset rainfall declines and reduced production in other areas.

  3. Topographic growth around the Orange River valley, southern Africa: A Cenozoic record of crustal deformation and climatic change

    Science.gov (United States)

    Dauteuil, Olivier; Bessin, Paul; Guillocheau, François

    2015-03-01

    We reconstruct the history of topographic growth in southern Africa on both sides of the Orange River valley from an integrated analysis of erosion surfaces, crustal deformation and climate change. First, we propose an inventory of erosion surfaces observed in the study area and classify them according to their most likely formative process, i.e. chemical weathering or mechanical erosion. Among the various land units observed we define a new class of landform: the pedivalley, which corresponds to a wide valley with a flat erosional floor. In the Orange River valley, we mapped three low-relief erosion surfaces, each bevelling a variety of lithologies. The oldest and most elevated is (1) a stripped etchplain evolving laterally into (2) a stepped pediplain bearing residual inselbergs; (3) a younger pediplain later formed in response to a more recent event of crustal deformation. These are all Cenozoic landforms: the etchplain is associated with a late Palaeocene to middle Eocene weathering event, and the two pediplains are older than the middle Miocene alluvial terraces of the Orange River. Landscape evolution was first driven by slow uplift (10 m/Ma), followed by a second interval of uplift involving a cumulative magnitude of at least 200 m. This event shaped the transition between the two pediplains and modified the drainage pattern. A final phase of uplift (magnitude: 60 m) occurred after the Middle Miocene and drove the incision of the lower terraces of the Orange River. Climate exerted a major control over the denudation process, and involved very humid conditions responsible for lateritic weathering, followed by more arid conditions, which promoted the formation of pedivalleys. Collectively, these produce pediplains.

  4. Changing atmospheric CO2 concentration was the primary driver of early Cenozoic climate.

    Science.gov (United States)

    Anagnostou, Eleni; John, Eleanor H; Edgar, Kirsty M; Foster, Gavin L; Ridgwell, Andy; Inglis, Gordon N; Pancost, Richard D; Lunt, Daniel J; Pearson, Paul N

    2016-05-19

    The Early Eocene Climate Optimum (EECO, which occurred about 51 to 53 million years ago), was the warmest interval of the past 65 million years, with mean annual surface air temperature over ten degrees Celsius warmer than during the pre-industrial period. Subsequent global cooling in the middle and late Eocene epoch, especially at high latitudes, eventually led to continental ice sheet development in Antarctica in the early Oligocene epoch (about 33.6 million years ago). However, existing estimates place atmospheric carbon dioxide (CO2) levels during the Eocene at 500-3,000 parts per million, and in the absence of tighter constraints carbon-climate interactions over this interval remain uncertain. Here we use recent analytical and methodological developments to generate a new high-fidelity record of CO2 concentrations using the boron isotope (δ(11)B) composition of well preserved planktonic foraminifera from the Tanzania Drilling Project, revising previous estimates. Although species-level uncertainties make absolute values difficult to constrain, CO2 concentrations during the EECO were around 1,400 parts per million. The relative decline in CO2 concentration through the Eocene is more robustly constrained at about fifty per cent, with a further decline into the Oligocene. Provided the latitudinal dependency of sea surface temperature change for a given climate forcing in the Eocene was similar to that of the late Quaternary period, this CO2 decline was sufficient to drive the well documented high- and low-latitude cooling that occurred through the Eocene. Once the change in global temperature between the pre-industrial period and the Eocene caused by the action of all known slow feedbacks (apart from those associated with the carbon cycle) is removed, both the EECO and the late Eocene exhibit an equilibrium climate sensitivity relative to the pre-industrial period of 2.1 to 4.6 degrees Celsius per CO2 doubling (66 per cent confidence), which is similar to the

  5. Climate Trends in the Slovak Part of the Carpathians

    Czech Academy of Sciences Publication Activity Database

    Melo, M.; Lapin, M.; Kapolková, H.; Pecho, Jozef; Kružicová, A.

    Berlin: Springer, 2013 - (Kozak, J.; Ostapowicz, K.; Bytnerowicz, A.; Wyzga, B.), s. 131-150. (Environmental Science and Engineering. Environmental Science). ISBN 978-3-642-12724-3 Institutional support: RVO:68378289 Keywords : climate change * climate trends * Carpathians * Slovakia Subject RIV: DG - Athmosphere Sciences, Meteorology http://link.springer.com/chapter/10.1007%2F978-3-642-12725-0_10

  6. The fingerprint of climate trends on European crop yields

    OpenAIRE

    Moore, Frances C.; Lobell, David B

    2015-01-01

    Agriculture is one of the economic sectors most exposed to climate change impacts, but few studies have statistically connected long-term changes in temperature and rainfall with yields. Doing so in Europe is particularly important because yields of wheat and barley have plateaued since the early 1990s and climate change has been suggested as a cause of this stagnation. Here, we show that the impact of climate trends can be detected in the pattern of long-term yield trends in Europe. Although...

  7. A climate trend analysis of Sudan

    Science.gov (United States)

    Funk, Christopher C.; Eilerts, Gary; Verdin, Jim; Rowland, Jim; Marshall, Michael

    2011-01-01

    Summer rains in western and southern Sudan have declined by 10-20 percent since the mid-1970s. Observed warming of more than 1 degree Celsius is equivalent to another 10-20 percent reduction in rainfall for crops. The warming and drying have impacted southern Darfur and areas around Juba. Rainfall declines west of Juba threaten southern Sudan's future food production prospects. In many cases, areas with changing climate are coincident with zones of substantial conflict, suggesting some degree of association; however, the contribution of climate change to these conflicts is not currently understood. Rapid population growth and the expansion of farming and pastoralism under a more variable climate regime could dramatically increase the number of at-risk people in Sudan over the next 20 years.

  8. A climate trend analysis of Chad

    Science.gov (United States)

    Funk, Christopher C.; Rowland, Jim; Adoum, Alkhalil; Eilerts, Gary; White, Libby

    2012-01-01

    This brief report, drawing from a multi-year effort by the U.S. Agency for International Development (USAID) Famine Early Warning Systems Network (FEWS NET), identifies significant decreases in rainfall and increases in air temperature across Chad, especially in the eastern part of the country. These analyses are based on quality-controlled station observations. Conclusions:* Summer rains have decreased in eastern Chad during the past 20 years. * Temperatures have increased by 0.8 °Celsius since 1975, amplifying the effect of droughts. * Crop yields are very low and stagnant. * The amount of farmland per person is low, and decliningrapidly.* Population growth combined with stagnating yieldscould lead to a 30 percent reduction in per capita cereal production by 2025.* In many cases, areas with changing climate are coincident with zones of substantial conflict, indicating some degree of association; however, the contribution of climate change to these conflicts is not currently understood.

  9. A climate trend analysis of Mali

    Science.gov (United States)

    Funk, Christopher C.; Rowland, Jim; Adoum, Alkhalil; Eilerts, Gary; White, Libby

    2012-01-01

    This brief report, drawing from a multi-year effort by the U.S. Agency for International Development (USAID) Famine Early Warning Systems Network (FEWS NET), identifies modest declines in rainfall, accompanied by increases in air temperatures. These analyses are based on quality-controlled station observations. Conclusions: * Summer rains have remained relatively steady for the past 20 years, but are 12 percent below the 1920-1969 average. * Temperatures have increased by 0.8° Celsius since 1975, amplifying the effect of droughts. * Cereal yields are low but have been improving. * Current population and agricultural trends indicate that increased yields have offset population expansion, keeping per capita cereal production steady.

  10. A Climate Trend Analysis of Burkina Faso

    Science.gov (United States)

    Funk, Christopher C.; Rowland, Jim; Eilerts, Gary; Adoum, Alkhalil; White, Libby

    2012-01-01

    This brief report, drawing from a multi-year effort by the U.S. Agency for International Development (USAID) Famine Early Warning Systems Network (FEWS NET), examines recent trends in rainfall and air temperatures. These analyses are based on quality controlled station observations. Conclusions: * Summer rains have remained steady over the past 20 years, but remain 15 percent below the 1920-69 average. * Temperatures have increased by 0.6° Celsius since 1975, amplifying the effect of droughts. * The amount of farmland per person is low, and declining. * Burkina Faso has offset rapid population growth with improved yields. * Continued yield growth would maintain current levels of per capita food production.

  11. A climate trend analysis of Senegal

    Science.gov (United States)

    Funk, Christopher C.; Rowland, Jim; Adoum, Alkhalil; Eilerts, Gary; Verdin, James; White, Libby

    2012-01-01

    This brief report, drawing from a multi-year effort by the U.S. Agency for International Development (USAID) Famine Early Warning Systems Network (FEWS NET), identifies modest declines in rainfall, accompanied by increases in air temperatures. These analyses are based on quality-controlled station observations. Conclusions: * Summer rains have remained steady in Senegal over the past 20 years but are 15 percent below the 1920-1969 average. * Temperatures have increased by 0.9° Celsius since 1975, amplifying the effect of droughts. * Cereal yields are low but have been improving. * The amount of farmland per person is low and declining rapidly. * Current population and agriculture trends could lead to a 30-percent reduction in per capita cereal production by 2025.

  12. Climate Trends and Farmers’ Perceptions of Climate Change in Zambia

    OpenAIRE

    Brian P. Mulenga; Wineman, Ayala

    2014-01-01

    In Zambia like in many other developing countries, the agricultural sector is highly dependent on rain-fed production and therefore vulnerable to weather shocks. Maize is the primary staple crop in Zambia, and is widely grown by smallholder farmers throughout the country, with a dual cassava-maize regime found only in the northern region. Among the smallholder farmers almost all production is rain-fed with very few farmers using mechanized irrigation. Climate change therefore has the potentia...

  13. Observing climate change trends in ocean biogeochemistry: when and where.

    Science.gov (United States)

    Henson, Stephanie A; Beaulieu, Claudie; Lampitt, Richard

    2016-04-01

    Understanding the influence of anthropogenic forcing on the marine biosphere is a high priority. Climate change-driven trends need to be accurately assessed and detected in a timely manner. As part of the effort towards detection of long-term trends, a network of ocean observatories and time series stations provide high quality data for a number of key parameters, such as pH, oxygen concentration or primary production (PP). Here, we use an ensemble of global coupled climate models to assess the temporal and spatial scales over which observations of eight biogeochemically relevant variables must be made to robustly detect a long-term trend. We find that, as a global average, continuous time series are required for between 14 (pH) and 32 (PP) years to distinguish a climate change trend from natural variability. Regional differences are extensive, with low latitudes and the Arctic generally needing shorter time series (temperature, but nevertheless the existing network of observatories only represents 9-15% of the global ocean surface. Our results present a quantitative framework for assessing the adequacy of current and future ocean observing networks for detection and monitoring of climate change-driven responses in the marine ecosystem. PMID:26742651

  14. The fingerprint of climate trends on European crop yields

    Science.gov (United States)

    Moore, Frances C.; Lobell, David B.

    2015-01-01

    Europe has experienced a stagnation of some crop yields since the early 1990s as well as statistically significant warming during the growing season. Although it has been argued that these two are causally connected, no previous studies have formally attributed long-term yield trends to a changing climate. Here, we present two statistical tests based on the distinctive spatial pattern of climate change impacts and adaptation, and explore their power under a range of parameter values. We show that statistical power for the identification of climate change impacts is high in many settings, but that power for identifying adaptation is almost always low. Applying these tests to European agriculture, we find evidence that long-term temperature and precipitation trends since 1989 have reduced continent-wide wheat and barley yields by 2.5% and 3.8%, respectively, and have slightly increased maize and sugar beet yields. These averages disguise large heterogeneity across the continent, with regions around the Mediterranean experiencing significant adverse impacts on most crops. This result means that climate trends can account for ∼10% of the stagnation in European wheat and barley yields, with likely explanations for the remainder including changes in agriculture and environmental policies. PMID:25691735

  15. Trends in global vegetation activity and climatic drivers indicate a decoupled response to climate change

    DEFF Research Database (Denmark)

    Schut, Antonius G T; Ivits, Eva; Conijn, Jacob G.; Ten Brink, Ben; Fensholt, Rasmus

    2015-01-01

    increasing difference between trends in climatic drivers and observed NDVI for large parts of the globe. Our findings suggest that future scenarios must consider impacts of constraints on plant growth such as extremes in weather and nutrient availability to predict changes in NPP and CO2 sequestration......Detailed understanding of a possible decoupling between climatic drivers of plant productivity and the response of ecosystems vegetation is required. We compared trends in six NDVI metrics (1982-2010) derived from the GIMMS3g dataset with modelled biomass productivity and assessed uncertainty in...... TBWper biome and land-use type. The simple linear and Thiel-Sen trends did not differ much whereas PWR increased the fraction of explained variation, depending on the NDVI metric considered. A positive trend in TBW indicating more favorable climatic conditions was found for 24% of pixels on land, and for...

  16. Trends in global vegetation activity and climatic drivers indicate a decoupled response to climate change

    DEFF Research Database (Denmark)

    Schut, Antonius G T; Ivits, Eva; Conijn, Jacob G.;

    2015-01-01

    an increasing difference between trends in climatic drivers and observed NDVI for large parts of the globe. Our findings suggest that future scenarios must consider impacts of constraints on plant growth such as extremes in weather and nutrient availability to predict changes in NPP and CO2 sequestration......Detailed understanding of a possible decoupling between climatic drivers of plant productivity and the response of ecosystems vegetation is required. We compared trends in six NDVI metrics (1982-2010) derived from the GIMMS3g dataset with modelled biomass productivity and assessed uncertainty......-NPP) and TBWper biome and land-use type. The simple linear and Thiel-Sen trends did not differ much whereas PWR increased the fraction of explained variation, depending on the NDVI metric considered. A positive trend in TBW indicating more favorable climatic conditions was found for 24% of pixels on land...

  17. WRF/ARPEGE-CLIMAT simulated climate trends over West Africa

    Energy Technology Data Exchange (ETDEWEB)

    Vigaud, N.; Roucou, P.; Fontaine, B. [UMR 5210 CNRS, Universite de Bourgogne, Centre de Recherches de Climatologie, Dijon (France); Sijikumar, S. [Space Physics Laboratory, Vikram Sarabhai Space Center, Trivandrum (India); Tyteca, S. [CNRM/GAME, URA 1357 CNRS/Meteo-France, Toulouse (France)

    2011-03-15

    The Weather Regional Forecast (WRF) model is used in this study to downscale low-resolution data over West Africa. First, the performance of the regional model is estimated through contemporary period experiments (1981-1990) forced by ARPEGE-CLIMAT GCM output (ARPEGE) and ERA-40 re-analyses. Key features of the West African monsoon circulation are reasonably well represented. WRF atmospheric dynamics and summer rainfall compare better to observations than ARPEGE forcing data. WRF simulated moisture transport over West Africa is also consistent in both structure and variability with re-analyses, emphasizing the substantial role played by the West African Monsoon (WAM) and African Easterly Jet (AEJ) flows. The statistical significance of potential climate changes for the A2 scenario between 2032 and 2041 is enhanced in the downscaling from ARPEGE by the regional experiments, with substantial rainfall increases over the Guinea Gulf and eastern Sahel. Future scenario WRF simulations are characterized by higher temperatures over the eastern Tropical Atlantic suggesting more evaporation available locally. This leads to increased moisture advection towards eastern regions of the Guinea Gulf where rainfall is enhanced through a strengthened WAM flow, supporting surface moisture convergence over West Africa. Warmer conditions over both the Mediterranean region and northeastern Sahel could also participate in enhancing moisture transport within the AEJ. The strengthening of the thermal gradient between the Sahara and Guinean regions, particularly pronounced north of 10 N, would support an intensification of the AEJ northwards, given the dependance of the jet to the position/intensity of the meridional gradient. In turn, mid-tropospheric moisture divergence tends to be favored within the AEJ region supporting southwards deflection of moist air and contributing to deep moist convection over the Sahel where late summer rainfall regimes are sustained in the context of the A2

  18. Using Google Dengue Trends to Estimate Climate Effects in Mexico

    OpenAIRE

    Gluskin, Rebecca T.; Santillana, Mauricio; John S Brownstein

    2013-01-01

    Objective: To evaluate the association between Dengue Fever (DF) and climate in Mexico with real-time data from Google Dengue Trends (GDT) and climate data from NASA Earth observing systems. Introduction: The incidence of dengue fever (DF) has increased 30 fold between 1960 and 2010 [1]. The literature suggests that temperature plays a major role in the life cycle of the mosquito vector and in turn, the timing of DF outbreaks [2]. We use real-time data from GDT and real-time temperature estim...

  19. Trends in Global Vegetation Activity and Climatic Drivers Indicate a Decoupled Response to Climate Change.

    Directory of Open Access Journals (Sweden)

    Antonius G T Schut

    Full Text Available Detailed understanding of a possible decoupling between climatic drivers of plant productivity and the response of ecosystems vegetation is required. We compared trends in six NDVI metrics (1982-2010 derived from the GIMMS3g dataset with modelled biomass productivity and assessed uncertainty in trend estimates. Annual total biomass weight (TBW was calculated with the LINPAC model. Trends were determined using a simple linear regression, a Thiel-Sen medium slope and a piecewise regression (PWR with two segments. Values of NDVI metrics were related to Net Primary Production (MODIS-NPP and TBW per biome and land-use type. The simple linear and Thiel-Sen trends did not differ much whereas PWR increased the fraction of explained variation, depending on the NDVI metric considered. A positive trend in TBW indicating more favorable climatic conditions was found for 24% of pixels on land, and for 5% a negative trend. A decoupled trend, indicating positive TBW trends and monotonic negative or segmented and negative NDVI trends, was observed for 17-36% of all productive areas depending on the NDVI metric used. For only 1-2% of all pixels in productive areas, a diverging and greening trend was found despite a strong negative trend in TBW. The choice of NDVI metric used strongly affected outcomes on regional scales and differences in the fraction of explained variation in MODIS-NPP between biomes were large, and a combination of NDVI metrics is recommended for global studies. We have found an increasing difference between trends in climatic drivers and observed NDVI for large parts of the globe. Our findings suggest that future scenarios must consider impacts of constraints on plant growth such as extremes in weather and nutrient availability to predict changes in NPP and CO2 sequestration capacity.

  20. Trends and variability in climate parameters of peshawar district

    International Nuclear Information System (INIS)

    Rain fall pattern, daily minimum and maximum temperatures and humidity are the main factors that constitute the climate of an area. In Pakistan, consecutive positive anomalies have been observed in minimum, maximum and mean temperatures and rainfall since mid 1970s. The objective of the current study was to investigate the recent trends and variability of annual minimum, maximum and mean temperatures, relative humidity and rainfall of Peshawar. Annual meteorological parameters for 30-years (1981-2010) of Peshawar observatory have been analysed to determine indications of variations from long-term averages. Different statistical methods were used to analyse the data. For this purpose, Mann-Kendall test was applied to Meteorological data of Peshawar (1981-2010) to study any trend, which were revealed to be in a mixture. The final results show that rainfall is decreasing, minimum temperature, mean temperature and relative humidity are increasing and maximum temperature has no change. Various factors could be responsible for the contemporary trends in climate like rise in number of vehicles and industries from reviewing available literature, keeping in mind the nature of the study. Trends found may have negative implications for agriculture, health and socioeconomic conditions of the region that require the attention from relevant stakeholders. (author)

  1. Arctic Climate Variability and Trends from Satellite Observations

    Directory of Open Access Journals (Sweden)

    Xuanji Wang

    2012-01-01

    Full Text Available Arctic climate has been changing rapidly since the 1980s. This work shows distinctly different patterns of change in winter, spring, and summer for cloud fraction and surface temperature. Satellite observations over 1982–2004 have shown that the Arctic has warmed up and become cloudier in spring and summer, but cooled down and become less cloudy in winter. The annual mean surface temperature has increased at a rate of 0.34°C per decade. The decadal rates of cloud fraction trends are −3.4%, 2.3%, and 0.5% in winter, spring, and summer, respectively. Correspondingly, annually averaged surface albedo has decreased at a decadal rate of −3.2%. On the annual average, the trend of cloud forcing at the surface is −2.11 W/m2 per decade, indicating a damping effect on the surface warming by clouds. The decreasing sea ice albedo and surface warming tend to modulate cloud radiative cooling effect in spring and summer. Arctic sea ice has also declined substantially with decadal rates of −8%, −5%, and −15% in sea ice extent, thickness, and volume, respectively. Significant correlations between surface temperature anomalies and climate indices, especially the Arctic Oscillation (AO index, exist over some areas, implying linkages between global climate change and Arctic climate change.

  2. Importance of ensembles in projecting regional climate trends

    Science.gov (United States)

    Arritt, Raymond; Daniel, Ariele; Groisman, Pavel

    2016-04-01

    We have performed an ensemble of simulations using RegCM4 to examine the ability to reproduce observed trends in precipitation intensity and to project future changes through the 21st century for the central United States. We created a matrix of simulations over the CORDEX North America domain for 1950-2099 by driving the regional model with two different global models (HadGEM2-ES and GFDL-ESM2M, both for RCP8.5), by performing simulations at both 50 km and 25 km grid spacing, and by using three different convective parameterizations. The result is a set of 12 simulations (two GCMs by two resolutions by three convective parameterizations) that can be used to systematically evaluate the influence of simulation design on predicted precipitation. The two global models were selected to bracket the range of climate sensitivity in the CMIP5 models: HadGEM2-ES has the highest ECS of the CMIP5 models, while GFDL-ESM2M has one of the lowestt. Our evaluation metrics differ from many other RCM studies in that we focus on the skill of the models in reproducing past trends rather than the mean climate state. Trends in frequency of extreme precipitation (defined as amounts exceeding 76.2 mm/day) for most simulations are similar to the observed trend but with notable variations depending on RegCM4 configuration and on the driving GCM. There are complex interactions among resolution, choice of convective parameterization, and the driving GCM that carry over into the future climate projections. We also note that biases in the current climate do not correspond to biases in trends. As an example of these points the Emanuel scheme is consistently "wet" (positive bias in precipitation) yet it produced the smallest precipitation increase of the three convective parameterizations when used in simulations driven by HadGEM2-ES. However, it produced the largest increase when driven by GFDL-ESM2M. These findings reiterate that ensembles using multiple RCM configurations and driving GCMs are

  3. Cenozoic tectonic and climatic events in southern Iberian Peninsula: Implications for the evolutionary history of freshwater fish of the genus Squalius (Actinopterygii, Cyprinidae).

    Science.gov (United States)

    Perea, Silvia; Cobo-Simon, Marta; Doadrio, Ignacio

    2016-04-01

    Southern Iberian freshwater ecosystems located at the border between the European and African plates represent a tectonically complex region spanning several geological ages, from the uplifting of the Betic Mountains in the Serravalian-Tortonian periods to the present. This area has also been subjected to the influence of changing climate conditions since the Middle-Upper Pliocene when seasonal weather patterns were established. Consequently, the ichthyofauna of southern Iberia is an interesting model system for analyzing the influence of Cenozoic tectonic and climatic events on its evolutionary history. The cyprinids Squalius malacitanus and Squalius pyrenaicus are allopatrically distributed in southern Iberia and their evolutionary history may have been defined by Cenozoic tectonic and climatic events. We analyzed MT-CYB (510 specimens) and RAG1 (140 specimens) genes of both species to reconstruct phylogenetic relationships and to estimate divergence times and ancestral distribution ranges of the species and their populations. We also assessed their levels of genetic structure and diversity as well as the amount of gene flow between populations. To investigate recent paleogeographical and climatic factors in southern Iberia, we modeled changes-through-time in sea level from the LGM to the present. Phylogenetic, geographic and population structure analyses revealed two well-supported species (S. malacitanus and S. pyrenaicus) in southern Iberia and two subclades (Atlantic and Mediterranean) within S. malacitanus. The origin of S. malacitanus and the separation of its Atlantic and Mediterranean populations occurred during the Serravalian-Tortonian and Miocene-Pliocene periods, respectively. These divergence events occurred in the Middle Pliocene and Pleistocene in S. pyrenaicus. In both species, Atlantic basins possessed populations with higher genetic diversity than Mediterranean, which may be explained by the Janda Lagoon. The isolation of S. malacitanus was

  4. Potential tropical Atlantic impacts on Pacific decadal climate trends

    Science.gov (United States)

    Chikamoto, Y.; Mochizuki, T.; Timmermann, A.; Kimoto, M.; Watanabe, M.

    2016-07-01

    The tropical Pacific cooling from the early 1990s to 2013 has contributed to the slowdown of globally averaged sea surface temperatures (SSTs). The origin of this regional cooling trend still remains elusive. Here we demonstrate that the remote impact of Atlantic SST anomalies, as well as local atmosphere-ocean interactions, contributed to the eastern Pacific cooling during this period. By assimilating observed three-dimensional Atlantic temperature and salinity anomalies into a coupled general circulation model, we are able to qualitatively reproduce the observed Pacific decadal trends of SST and sea level pressure (SLP), albeit with reduced amplitude. Although a major part of the Pacific SLP trend can be explained by equatorial Pacific SST forcing only, the origin of this low-frequency variability can be traced back further to the remote impacts of equatorial Atlantic and South Atlantic SST trends. Atlantic SST impacts on the atmospheric circulation can also be detected for the Northeastern Pacific, thus providing a linkage between Atlantic climate and Western North American drought conditions.

  5. Climate change and transnational corporations. Analysis and trends

    International Nuclear Information System (INIS)

    In Economic and Social Council resolution 1989/25, the Council requested an analytic study of the main sectors of activity that have adverse effects on environmental preservation and the factors that determine the allocation of activities between developed and developing countries. The present report, entitled Climate Change and Transnational Corporations: Analysis and Trends, is in response to that request. The problem of global warming and the dangers it presents to global survival are being given high priority by the United Nations. Discussions are under way leading to a convention on global climate change under the auspices of United Nations intergovernmental bodies. The study was designed as a contribution to that process. It focuses on six transnational energy-producing and energy-consuming industrial sectors, in which corporate practices have a direct and major impact on the problems associated with global climate change. The sectors are fossil fuel production, transportation, electricity-generation, energy-intensive metals production, chlorofluorocarbons and other ozone-depleting chemicals, and inorganic nitrogen fertilizers. The study explores the relative differential impacts between industrialized and developing countries of each sector, and asks how each sector would have to be restructured in order to limit global climate change and ozone depletion. It concludes that major changes in the technical processes and investment patterns of the transnational corporations in those sectors would be necessary if catastrophic environmental changes are to be avoided

  6. INTERTEMPORAL AND INTERSPATIAL VARIABILITY OF CLIMATE CHANGE ON DRYLAND WINTER WHEAT YIELD TRENDS

    OpenAIRE

    Shaik, Saleem; Helmers, Glenn A.

    2000-01-01

    The importance of climate (temperature and precipitation) variability on Nebraska dryland winter wheat yield trend is examined. The use of short term (1956-1999) climatic divisional panel data (interspatial) and long term (1909-1999) state time series data (intertemporal) is to address the predictability power of estimating the yield trends accounting for climate variability.

  7. Climatic trends in Estonia during the period of instrumental observations and climate scenarios

    International Nuclear Information System (INIS)

    Weather conditions in Estonia are quite variable. Long-term periodical fluctuations have been observed in meteorological values. At the same time, the climate change during the last 100-150 years is marked. As a general tendency, the climate has become more maritime. Air pressure is characterized by an increasing trend in spring and summer, and by a decreasing trend in autumn and winter. Mean air temperature has increased, particularly over the colder half of the year. Precipitation area totals have risen, most of all in autumn and winter. Snow cover duration has decreased significantly. General circulation model-based climate change scenarios expect a general increase in air temperature in Estonia with warming in winter more significant than that in summer. Moreover, they indicate an increase in precipitation, but the results of the individual models are quite variable. The transient scenario shows that the main increase in precipitation will not occur during next decades, but only at the end of the transient period, around 2070. It can be stated that observed tendencies of climate change in Estonia concur with expected changes caused by global warming. According to the long-term fluctuations of meteorological values in Estonia, changes different from general trends can take place during the next decade. An increase in mean air pressure, sunshine duration and snow cover duration, as well as a decrease in mean air temperature and precipitation is expected in the following years

  8. Detection of trends in surface ozone in the presence of climate variability

    Science.gov (United States)

    Barnes, Elizabeth A.; Fiore, Arlene M.; Horowitz, Larry W.

    2016-05-01

    Trends in trace atmospheric constituents can be driven not also by trends in their (precursor) emissions but also by trends in meteorology. Here we use ground-level ozone as an example to highlight the extent to which unforced, low-frequency climate variability can drive multidecadal trends. Using output from six experiments of the Geophysical Fluid Dynamics Laboratory chemistry-climate model (CM3), we demonstrate that 20 year trends in surface ozone driven by climate variability alone can be as large as those forced by changes in ozone precursor emissions or by anthropogenic climate change. We highlight regions and seasons where surface ozone is strongly influenced by climate variability and thus where a given forced trend may be more difficult to detect. A corollary is that this approach identifies regions and seasons of low variability, where measurement sites may be most effectively deployed to detect a particular trend driven by changing precursor emissions. We find that the representative concentration pathways 4.5 (RCP4.5) and RCP8.5 forced surface ozone trends in most locations emerge over background variability during the first half of the 21st century. Ozone trends are found to respond mostly to changes in emissions of ozone precursors and unforced climate variability, with a comparatively small impact from anthropogenic climate change. Thus, attempts to attribute observed trends to regional emissions changes require consideration of internal climate variability, particularly for short record lengths and small forced trends.

  9. Dragonflies and climatic change - recent trends in Germany and Europe

    Directory of Open Access Journals (Sweden)

    Jürgen Ott

    2010-12-01

    Full Text Available In this paper the trends of dragonfly expansions during the last decades in Germany and Europe are summarized. It is shown, that there is a general expansion of many species to the north: Mediterranean species expanded to Central and Northern Europe, whereas some African species expanded to Southern Europe, some are even new to the continent. In general this means an increase of biodiversity, but looking at the ecological effects, in the medium term a decrease can be expected for mooreland and alpine species. Dragonflies can be regarded as a good indicator group for climatic change. Already now in some areas or regions negative effects on waters bodies and their dragonfly communities can be observed and more will occur if e.g. temperature rises or precipitation decreases. The consequences for nature conservation strategies – such as the NATURA 2000 network – are outlined and the general need for monitoring programmes is emphasised.

  10. Are climate model simulations useful for forecasting precipitation trends? Hindcast and synthetic-data experiments

    International Nuclear Information System (INIS)

    Water scientists and managers currently face the question of whether trends in climate variables that affect water supplies and hazards can be anticipated. We investigate to what extent climate model simulations may provide accurate forecasts of future hydrologic nonstationarity in the form of changes in precipitation amount. We compare gridded station observations (GPCC Full Data Product, 1901–2010) and climate model outputs (CMIP5 Historical and RCP8.5 simulations, 1901–2100) in real and synthetic-data hindcast experiments. The hindcast experiments show that imputing precipitation trends based on the climate model mean reduced the root mean square error of precipitation trend estimates for 1961–2010 by 9% compared to making the assumption (implied by hydrologic stationarity) of no trend in precipitation. Given the accelerating pace of climate change, the benefits of incorporating climate model assessments of precipitation trends in water resource planning are projected to increase for future decades. The distribution of climate models’ simulated precipitation trends shows substantial spatially coherent biases, suggesting that there may be room for further improvement in how climate models are parametrized and used for precipitation estimation. Linear extrapolation of observed trends in long precipitation records may also be useful, particularly for lead times shorter than about 25 years. Overall, our findings suggest that simulations by current global climate models, combined with the continued maintenance of in situ hydrologic observations, can provide useful information on future changes in the hydrologic cycle. (paper)

  11. Climate-driven trends in contemporary ocean productivity.

    Science.gov (United States)

    Behrenfeld, Michael J; O'Malley, Robert T; Siegel, David A; McClain, Charles R; Sarmiento, Jorge L; Feldman, Gene C; Milligan, Allen J; Falkowski, Paul G; Letelier, Ricardo M; Boss, Emmanuel S

    2006-12-01

    Contributing roughly half of the biosphere's net primary production (NPP), photosynthesis by oceanic phytoplankton is a vital link in the cycling of carbon between living and inorganic stocks. Each day, more than a hundred million tons of carbon in the form of CO2 are fixed into organic material by these ubiquitous, microscopic plants of the upper ocean, and each day a similar amount of organic carbon is transferred into marine ecosystems by sinking and grazing. The distribution of phytoplankton biomass and NPP is defined by the availability of light and nutrients (nitrogen, phosphate, iron). These growth-limiting factors are in turn regulated by physical processes of ocean circulation, mixed-layer dynamics, upwelling, atmospheric dust deposition, and the solar cycle. Satellite measurements of ocean colour provide a means of quantifying ocean productivity on a global scale and linking its variability to environmental factors. Here we describe global ocean NPP changes detected from space over the past decade. The period is dominated by an initial increase in NPP of 1,930 teragrams of carbon a year (Tg C yr(-1)), followed by a prolonged decrease averaging 190 Tg C yr(-1). These trends are driven by changes occurring in the expansive stratified low-latitude oceans and are tightly coupled to coincident climate variability. This link between the physical environment and ocean biology functions through changes in upper-ocean temperature and stratification, which influence the availability of nutrients for phytoplankton growth. The observed reductions in ocean productivity during the recent post-1999 warming period provide insight on how future climate change can alter marine food webs. PMID:17151666

  12. A climatic deconstruction of recent drought trends in the United States

    International Nuclear Information System (INIS)

    We present high spatial-resolution trends of the Palmer drought severity index (PDSI), potential evapotranspiration (PET), and selected climate variables from 1979–2013 for the contiguous United States in order to gain an understanding of recent drought trends and their climatic forcings. Based on a spatial grouping analysis, four regions of increasing (upper Midwest, Louisiana, southeastern United States (US), and western US) and decreasing (New England, Pacific Northwest, upper Great Plains, and Ohio River Valley) drought trends based on Mann–Kendall Z values were found. Within these regions, partial correlation and multiple regression for trends in climate variables and PDSI were performed to examine potential climatic controls on these droughts. As expected, there was a US-wide concurrence on drought forcing by precipitation. However, there was correspondence of recent PET trends with recent drought trends in many regions. For regions with an increase in recent droughts, average air temperature was generally the second most important variable after precipitation in determining recent drought trends. Across the regions where recent drought trends are decreasing, there was no clear ranking of climate-variable importance, where trends in average temperature, specific humidity and net radiation all played significant regional roles in determining recent drought trends. Deconstructing the trends in drought show that, while there are regions in the US showing positive and negative trends in drought conditions, the climate forcings for these drought trends are regionally specific. The results of this study allow for the interpretation of the role of the changing hydroclimatic cycle in recent drought trends, which also have implications for the current and impending results of climate change. (letter)

  13. The capability of the ALARO-Climate RCM to simulate observed temperature trends

    Czech Academy of Sciences Publication Activity Database

    Pokorná, Lucie; Huth, Radan; Farda, Aleš; Metelka, L.

    Brusel: European Commission, 2013. [International Conference on Regional Climate - CORDEX 2013. 04.11.2013-07.11.2013, Brussels] R&D Projects: GA ČR(CZ) GAP209/11/2405 Keywords : regional climatic model * temperature * trend Subject RIV: DG - Athmosphere Sciences, Meteorology http://cordex2013.wcrp-climate.org/cordex2013_documents/abstract_book.pdf

  14. Climate trends, the U.S. drought of 1988, and access to data

    International Nuclear Information System (INIS)

    Selected climate trends are presented, together with information about selected data sets, and where a scientist can find more data for climate research. One source of plots of climatic indices is referenced. Plans for reanalysis of the atmosphere for 35 years are summarized. The greenhouse effect and the US drought of 1988 are discussed

  15. Climate trends, the U.S. drought of 1988, and access to data

    International Nuclear Information System (INIS)

    Selected climate trends are presented, together with information about selected data sets, and where a scientist can find more data for climate research. One source of plots of climatic indices is referenced. Plans for reanalysis of the atmosphere for 35 years are summarized. The greenhouse effect and the US drought of 1988 are discussed. 26 refs.; 3 figs

  16. From School of Rock to Building Core Knowledge: Teaching about Cenozoic climate change with data and case studies from the primary literature

    Science.gov (United States)

    Leckie, R. M.; St John, K. K.; Jones, M. H.; Pound, K. S.; Krissek, L. A.; Peart, L. W.

    2011-12-01

    The School of Rock (SoR) began in 2005 as a pilot geoscience professional development program for K-12 teachers and informal educators aboard the JOIDES Resolution (JR). Since then, the highly successful SoR program, sponsored by the Consortium for Ocean Leadership's Deep Earth Academy, has conducted on-shore professional development at the Integrated Ocean Drilling Program (IODP) core repository in College Station, TX, and on the JR. The success of the SoR program stems from the natural synergy that develops between research scientists and educators when their combined pedagogical skills and scientific knowledge are used to uncover a wealth of scientific ocean drilling discoveries and research findings. Educators are challenged with authentic inquiry based on sediment archives; these lessons from the past are then made transferable to the general public and to classrooms through the creation of age-appropriate student-active learning materials (http://www.oceanleadership.org/education/deep-earth-academy/educators/classroom-activities/). This science made accessible approach was the basis for a successful NSF Course Curriculum and Laboratory Improvement (CCLI) proposal to develop teaching materials for use at the college level. Our Building Core Knowledge project resulted in a series of 14 linked, yet independent, inquiry-based exercise modules around the theme of Reconstructing Earth's Climate History. All of the exercises build upon authentic data from peer reviewed scientific publications. These multiple part modules cover fundamental paleoclimate principles, tools and proxies, and Cenozoic case studies. It is important to teach students how we know what we know. For example, paleoclimate records must be systematically described, ages must be determined, and indirect evidence (i.e., proxies) of past climate must be analyzed. Much like the work of a detective, geoscientists and paleoclimatologists reconstruct what happened in the past, and when and how it

  17. Cenozoic climate change and diversification on the continental shelf and slope: evolution of gastropod diversity in the family Solariellidae (Trochoidea).

    Science.gov (United States)

    Williams, S T; Smith, L M; Herbert, D G; Marshall, B A; Warén, A; Kiel, S; Dyal, P; Linse, K; Vilvens, C; Kano, Y

    2013-04-01

    Recent expeditions have revealed high levels of biodiversity in the tropical deep-sea, yet little is known about the age or origin of this biodiversity, and large-scale molecular studies are still few in number. In this study, we had access to the largest number of solariellid gastropods ever collected for molecular studies, including many rare and unusual taxa. We used a Bayesian chronogram of these deep-sea gastropods (1) to test the hypothesis that deep-water communities arose onshore, (2) to determine whether Antarctica acted as a source of diversity for deep-water communities elsewhere and (3) to determine how factors like global climate change have affected evolution on the continental slope. We show that although fossil data suggest that solariellid gastropods likely arose in a shallow, tropical environment, interpretation of the molecular data is equivocal with respect to the origin of the group. On the other hand, the molecular data clearly show that Antarctic species sampled represent a recent invasion, rather than a relictual ancestral lineage. We also show that an abrupt period of global warming during the Palaeocene Eocene Thermal Maximum (PETM) leaves no molecular record of change in diversification rate in solariellids and that the group radiated before the PETM. Conversely, there is a substantial, although not significant increase in the rate of diversification of a major clade approximately 33.7 Mya, coinciding with a period of global cooling at the Eocene-Oligocene transition. Increased nutrients made available by contemporaneous changes to erosion, ocean circulation, tectonic events and upwelling may explain increased diversification, suggesting that food availability may have been a factor limiting exploitation of deep-sea habitats. Tectonic events that shaped diversification in reef-associated taxa and deep-water squat lobsters in central Indo-West Pacific were also probably important in the evolution of solariellids during the Oligo

  18. An atmosphere-ocean GCM modelling study of the climate response to changing Arctic seaways in the early Cenozoic.

    Science.gov (United States)

    Roberts, C. D.; Legrande, A. N.; Tripati, A. K.

    2008-12-01

    previous findings on the potential influence of Arctic gateways on ocean overturning and also suggests that Northern Hemisphere climate, particularly in the North Atlantic, was very sensitive to changes in Arctic seaways. This result is of particular significance when considered in the context of the Paleocene Eocene Thermal Maximum (PETM). Volcanic activity prior to the PETM may have been responsible for the formation of a sub-aerial barrier in the North Atlantic, and consequently may have driven warming of intermediate waters sufficient to destabilize methane clathrates. Evidence for freshening of Arctic ocean waters prior to the PETM would support this hypothesis.

  19. Climate change or climate cycles? Snowpack trends in the Olympic and Cascade Mountains, Washington, USA.

    Science.gov (United States)

    Barry, Dwight; McDonald, Shea

    2013-01-01

    Climate change could significantly influence seasonal streamflow and water availability in the snowpack-fed watersheds of Washington, USA. Descriptions of snowpack decline often use linear ordinary least squares (OLS) models to quantify this change. However, the region's precipitation is known to be related to climate cycles. If snowpack decline is more closely related to these cycles, an OLS model cannot account for this effect, and thus both descriptions of trends and estimates of decline could be inaccurate. We used intervention analysis to determine whether snow water equivalent (SWE) in 25 long-term snow courses within the Olympic and Cascade Mountains are more accurately described by OLS (to represent gradual change), stationary (to represent no change), or step-stationary (to represent climate cycling) models. We used Bayesian information-theoretic methods to determine these models' relative likelihood, and we found 90 models that could plausibly describe the statistical structure of the 25 snow courses' time series. Posterior model probabilities of the 29 "most plausible" models ranged from 0.33 to 0.91 (mean = 0.58, s = 0.15). The majority of these time series (55%) were best represented as step-stationary models with a single breakpoint at 1976/77, coinciding with a major shift in the Pacific Decadal Oscillation. However, estimates of SWE decline differed by as much as 35% between statistically plausible models of a single time series. This ambiguity is a critical problem for water management policy. Approaches such as intervention analysis should become part of the basic analytical toolkit for snowpack or other climatic time series data. PMID:22411029

  20. Trend assessment: applications for hydrology and climate research

    Directory of Open Access Journals (Sweden)

    M. Kallache

    2005-01-01

    Full Text Available The assessment of trends in climatology and hydrology still is a matter of debate. Capturing typical properties of time series, like trends, is highly relevant for the discussion of potential impacts of global warming or flood occurrences. It provides indicators for the separation of anthropogenic signals and natural forcing factors by distinguishing between deterministic trends and stochastic variability. In this contribution river run-off data from gauges in Southern Germany are analysed regarding their trend behaviour by combining a deterministic trend component and a stochastic model part in a semi-parametric approach. In this way the trade-off between trend and autocorrelation structure can be considered explicitly. A test for a significant trend is introduced via three steps: First, a stochastic fractional ARIMA model, which is able to reproduce short-term as well as long-term correlations, is fitted to the empirical data. In a second step, wavelet analysis is used to separate the variability of small and large time-scales assuming that the trend component is part of the latter. Finally, a comparison of the overall variability to that restricted to small scales results in a test for a trend. The extraction of the large-scale behaviour by wavelet analysis provides a clue concerning the shape of the trend.

  1. Long-term trends of the Polar and Arctic cells influencing the Arctic climate since 1989

    Science.gov (United States)

    Qian, Weihong; Wu, Kaijun; Leung, Jeremy Cheuk-Hin; Shi, Jian

    2016-03-01

    The strengthening and broadening trends of the Hadley cell have been revealed, while the existence of the Arctic cell has also been confirmed in previous studies. This study extends previous strengthening trend analyses of the Hadley cell to the Polar and Arctic cells in the Northern Hemisphere and explores their climate influences. Results show that the Polar cell experienced an abrupt change from a slow to a rapid strengthening trend in 1989, while the Arctic cell showed an insignificant strengthening trend and a significant weakening trend successively. The strengthening subsidence flow associated with the Polar and Arctic cells can partly explain the warming surface air temperature and declining sea ice concentration through the increasing tropospheric height and temperature trends. These results provide new insights for understanding the interdecadal relationship between atmospheric circulation and climate change in the Arctic region.

  2. Climate-driven population responses of resident brown trout, Salmo trutta: Trends and future projections

    OpenAIRE

    2016-01-01

    The climate is changing at an alarming rate with consequences such as species and population extinctions, changes in species distribution and phenology. However, mechanisms underlying these global trends are not well understood, especially at a population level. Climate effects on demographic traits and population dynamics have recently received increasing attention as key importance for understanding the ecological impacts of climate change. The effects on demographic traits might vary acros...

  3. Climate science: Hidden trends in the ocean carbon sink

    Science.gov (United States)

    Ilyina, Tatiana

    2016-02-01

    Simulations of the flux of atmospheric carbon dioxide into the ocean show that changes in flux associated with human activities are currently masked by natural climate variations, but will be evident in the near future. See Letter p.469

  4. INSURANCE MARKET TRENDS CAUSED BY CLIMATE CHANGE Flavia BARNA

    OpenAIRE

    Flavia Barna; Victoria Şeulean; Petru-Ovidiu Mura

    2011-01-01

    Uncertain behavior of extreme weather events is critical for insurance because of the financial effects that it generates. In this context, the effects of climate change on the frequency and hardness of natural disasters are vital information in order to restructure the portfolio of insurance products. Creation of new insurance products and schemes focused on protecting against the risks of climate change is a goal of the insurance companies. The financial innovation in the insurance field al...

  5. A climate trend analysis of Kenya-August 2010

    Science.gov (United States)

    Funk, Christopher C.

    2010-01-01

    Introduction This brief report draws from a multi-year effort by the United States Agency for International Development's Famine Early Warning System Network (FEWS NET) to monitor and map rainfall and temperature trends over the last 50 years (1960-2009) in Kenya. Observations from seventy rainfall gauges and seventeen air temperature stations were analyzed for the long rains period, corresponding to March through June (MAMJ). The data were quality controlled, converted into 1960-2009 trend estimates, and interpolated using a rigorous geo-statistical technique (kriging). Kriging produces standard error estimates, and these can be used to assess the relative spatial accuracy of the identified trends. Dividing the trends by the associated errors allows us to identify the relative certainty of our estimates (Funk and others, 2005; Verdin and others, 2005; Brown and Funk, 2008; Funk and Verdin, 2009). Assuming that the same observed trends persist, regardless of whether or not these changes are due to anthropogenic or natural cyclical causes, these results can be extended to 2025, providing critical, and heretofore missing information about the types and locations of adaptation efforts that may be required to improve food security.

  6. Recent climate change in Japan – spatial and temporal characteristics of trends of temperature

    Directory of Open Access Journals (Sweden)

    M. Domroes

    2008-04-01

    Full Text Available In this paper temperature series of Japan were statistically analysed in order to answer the question whether recent climate change can be proved for Japan; the results were compared and discussed with the global trends. The observations in Japan started for some stations in the 1870s, 59 stations are available since 1901, 136 stations since 1959. Modern statistical methods were applied, such as: Gaussian binominal low-pass filter (30 yr, trend analysis (linear regression model including the trend-to-noise-ratio as measure of significance and the non-parametric, non-linear trend test according to MANN (MANN's Q. According to the results of the analyses, climate change in Japan is clearly shown for temperature over the 100 yr (1901–2000: Annual mean temperatures increased at all stations from 0.35 (Hakodate to 2.95°C (Tokyo. The magnitude of climate change is illustrated to increase over the recent period 1976–2000. Seasonally, the strongest warming trends were observed for winter temperatures and also increasing temperature trends prevailed in summer, with the exception of slightly decreasing trends at only four stations. As far as temperatures are concerned, a distinct increase could be shown over the period 1901–2000 with a strong trend of warming over the more recent period 1976–2000.

  7. Trends in projections of standardized precipitation indices in a future climate in Poland

    Science.gov (United States)

    Osuch, Marzena; Romanowicz, Renata J.; Lawrence, Deborah; Wong, Wai K.

    2016-05-01

    Possible future climate change effects on dryness conditions in Poland are estimated for six climate projections using the standardized precipitation index (SPI). The time series of precipitation represent six different climate model runs under the selected emission scenario for the period 1971-2099. Monthly precipitation values were used to estimate the SPI for multiple timescales (1, 3, 6, 12, and 24 months) for a spatial resolution of 25 km for the whole country. Trends in the SPI were analysed using the Mann-Kendall test with Sen's slope estimator for each grid cell for each climate model projection and aggregation scale, and results obtained for uncorrected precipitation and bias corrected precipitation were compared. Bias correction was achieved using a distribution-based quantile mapping (QM) method in which the climate model precipitation series were adjusted relative to gridded precipitation data for Poland. The results show that the spatial pattern of the trend depends on the climate model, the timescale considered and on the bias correction. The effect of change on the projected trend due to bias correction is small compared to the variability among climate models. We also summarize the mechanisms underlying the influence of bias correction on trends in precipitation and the SPI using a simple example of a linear bias correction procedure. In both cases, the bias correction by QM does not change the direction of changes but can change the slope of trend, and the influence of bias correction on SPI is much reduced. We also have noticed that the results for the same global climate model, driving different regional climate model, are characterized by a similar pattern of changes, although this behaviour is not seen at all timescales and seasons.

  8. Global climate models’ bias in surface temperature trends and variability

    International Nuclear Information System (INIS)

    The Earth has warmed in the last century with the most rapid warming occurring near the surface in the Arctic. This Arctic amplification occurs partly because the extra heat is trapped in a thin layer of air near the surface due to the persistent stable-stratification found in this region. The amount of warming depends upon the extent of turbulent mixing in the atmosphere, which is described by the depth of the atmospheric boundary layer (ABL). Global climate models (GCMs) tend to over-estimate the depth of stably-stratified ABLs, and here we show that GCM biases in the ABL depth are strongly correlated with biases in the surface temperature variability. This highlights the need for a better description of the stably-stratified ABL in GCMs in order to constrain the current uncertainty in climate variability and projections of climate change in the surface layer. (letter)

  9. Quantifying the effect of trend, fluctuation, and extreme event of climate change on ecosystem productivity.

    Science.gov (United States)

    Liu, Yupeng; Yu, Deyong; Su, Yun; Hao, Ruifang

    2014-12-01

    Climate change comprises three fractions of trend, fluctuation, and extreme event. Assessing the effect of climate change on terrestrial ecosystem requires an understanding of the action mechanism of these fractions, respectively. This study examined 11 years of remotely sensed-derived net primary productivity (NPP) to identify the impacts of the trend and fluctuation of climate change as well as extremely low temperatures caused by a freezing disaster on ecosystem productivity in Hunan province, China. The partial least squares regression model was used to evaluate the contributions of temperature, precipitation, and photosynthetically active radiation (PAR) to NPP variation. A climatic signal decomposition and contribution assessment model was proposed to decompose climate factors into trend and fluctuation components. Then, we quantitatively evaluated the contributions of each component of climatic factors to NPP variation. The results indicated that the total contribution of the temperature, precipitation, and PAR to NPP variation from 2001 to 2011 in Hunan province is 85 %, and individual contributions of the temperature, precipitation, and PAR to NPP variation are 44 % (including 34 % trend contribution and 10 % fluctuation contribution), 5 % (including 4 % trend contribution and 1 % fluctuation contribution), and 36 % (including 30 % trend contribution and 6 % fluctuation contribution), respectively. The contributions of temperature fluctuation-driven NPP were higher in the north and lower in the south, and the contributions of precipitation trend-driven NPP and PAR fluctuation-driven NPP are higher in the west and lower in the east. As an instance of occasionally triggered disturbance in 2008, extremely low temperatures and a freezing disaster produced an abrupt decrease of NPP in forest and grass ecosystems. These results prove that the climatic trend change brought about great impacts on ecosystem productivity and that climatic fluctuations and

  10. Technology and Climate Trends in PV Module Degradation: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, D. C.; Wohlgemuth, J. H.; Kurtz, S. R.

    2012-10-01

    To sustain the commercial success of photovoltaic (PV) technology it is vital to know how power output decreases with time. Unfortunately, it can take years to accurately measure the long-term degradation of new products, but past experience on older products can provide a basis for prediction of degradation rates of new products. An extensive search resulted in more than 2000 reported degradation rates with more than 1100 reported rates that include some or all IV parameters. In this paper we discuss how the details of the degradation data give clues about the degradation mechanisms and how they depend on technology and climate zones as well as how they affect current and voltage differently. The largest contributor to maximum power decline for crystalline Si technologies is short circuit current (or maximum current) degradation and to a lesser degree loss in fill factor. Thin-film technologies are characterized by a much higher contribution from fill factor particularly for humid climates. Crystalline Si technologies in hot & humid climates also display a higher probability to show a mixture of losses (not just short circuit current losses) compared to other climates. The distribution for the module I-V parameters (electrical mismatch) was found to change with field exposure. The distributions not only widened but also developed a tail at the lower end, skewing the distribution.

  11. Long-term trends in geomagnetic and climatic variability

    Czech Academy of Sciences Publication Activity Database

    Bucha, Václav

    2002-01-01

    Roč. 27, 6/7 (2002), s. 427-731. ISSN 1474-7065 R&D Projects: GA AV ČR IAA3012806 Institutional research plan: CEZ:AV0Z3012916 Keywords : geomagnetic forcing * climatic variability * global warming Subject RIV: DE - Earth Magnetism, Geodesy, Geography

  12. Health in climate change research from 1990 to 2014: positive trend, but still underperforming

    OpenAIRE

    Verner, Glenn; Schütte, Stefanie; Knop, Juliane; Sankoh, Osman; Sauerborn, Rainer

    2016-01-01

    Background: Climate change has been recognized as both one of the biggest threats and the biggest opportunities for global health in the 21st century. This trend review seeks to assess and characterize the amount and type of scientific literature on the link between climate change and human health.Design: We tracked the use of climate-related terms and their co-occurrence with health terms during the 25 years since the first Intergovernmental Panel on Climate Change (IPCC) report, from 1990 t...

  13. Analysing the Cenozoic depositional record

    DEFF Research Database (Denmark)

    Goledowski, Bartosz; Clausen, O.R.; Nielsen, S.B.

    between the global climate record (oxygen isotopes) and lithology variations on the Eocene-Oligocene transition in the eastern North Sea. Due to the strongly limited time resolution of low temperature thermochronology, the Cenozoic sedimentary record potentially provides the most detailed history of...... lower limit to erosion rate in source areas of the respective sedimentary bodies. The lower limit arises because some erosional products are transported out of the mapped area, and some erosion is caused by chemical dissolution. The development of the source areas will be modelled using surface process...... models. The matrix mass deposition history will be compared with the paleoclimate record (e.g. oxygen isotope curves) to see if the previously observed correlation in the eastern North Sea can be extended to other ages and locations.  ...

  14. Dragonflies and climatic change - recent trends in Germany and Europe

    OpenAIRE

    Jürgen Ott

    2010-01-01

    In this paper the trends of dragonfly expansions during the last decades in Germany and Europe are summarized. It is shown, that there is a general expansion of many species to the north: Mediterranean species expanded to Central and Northern Europe, whereas some African species expanded to Southern Europe, some are even new to the continent. In general this means an increase of biodiversity, but looking at the ecological effects, in the medium term a decrease can be expected for mooreland an...

  15. Southern Ocean Sector Centennial Climate Variability and Recent Decadal Trends

    OpenAIRE

    Latif, Mojib; Martin, Torge; Park, Wonsun

    2013-01-01

    Evidence is presented for the notion that some contribution to the recent decadal trends observed in the Southern Hemisphere, including the lack of a strong Southern Ocean surface warming, may have originated from longer-term internal centennial variability originating in the Southern Ocean. The existence of such centennial variability is supported by the instrumental sea surface temperatures (SSTs), a multimillennial reconstruction of Tasmanian summer temperatures from tree rings, and a mill...

  16. Recent climate change in Japan – spatial and temporal characteristics of trends of temperature

    Directory of Open Access Journals (Sweden)

    D. Schaefer

    2009-02-01

    Full Text Available In this paper temperature series of Japan were statistically analysed in order to answer the question whether recent climate change can be proved for Japan; the results were compared and discussed with the global trends. The observations in Japan started for some stations in the 1870s, 59 stations are available since 1901, 136 stations since 1959. Modern statistical methods were applied, such as: Gaussian binominal low-pass filter (30 yr, trend analysis (linear regression model including the trend-to-noise-ratio as measure of significance and the non-parametric, non-linear trend test according to MANN (MANN's Q. According to the results of the analyses, climate change in Japan is clearly shown for temperature over the 100 yr (1901–2000: Annual mean temperatures increased at all stations from 0.35 (Hakodate to 2.95°C (Tokyo. The magnitude of climate change is illustrated to increase over the recent period 1976–2000. Seasonally, the strongest warming trends were observed for winter temperatures and also increasing temperature trends prevailed in summer, with the exception of slightly decreasing trends at only four stations.

  17. Late Cenozoic geomorphologic signal of Andean forearc deformation and tilting associated with the uplift and climate changes of the Southern Atacama Desert (26 degrees S-28 degrees S)

    OpenAIRE

    Riquelme, R.; Hérail, Gérard; Martinod, J.; Charrier, R.; Darrozes, J

    2007-01-01

    We analyze remarkable examples of the large (similar to 10,000 km(2)) and local-scale (similar to 100 km(2)) landscape forms related to Late Cenozoic geomorphologic evolution of the Andean forearc region in the Southern Atacama Desert. We also consider the continental sedimentary deposits, so-called "Atacama Gravels", which are related to the degradation of the landscape during the Neogene. Our analysis integrates 1:50,000 field cartography, Landsat TM images observations, similar to 1:1000 s...

  18. CLIMATE CHANGE: LONG-TERM TRENDS AND SHORT-TERM OSCILLATIONS

    Institute of Scientific and Technical Information of China (English)

    GAO Xin-quan; ZHANG Xin; QIAN Wei-hong

    2006-01-01

    Identifying the Northern Hemisphere (NH) temperature reconstruction and instrumental data for the past 1000 years shows that climate change in the last millennium includes long-term trends and various oscillations. Two long-term trends and the quasi-70-year oscillation were detected in the global temperature series for the last 140 years and the NH millennium series. One important feature was emphasized that temperature decreases slowly but it increases rapidly based on the analysis of different series. Benefits can be obtained of climate change from understanding various long-term trends and oscillations. Millennial temperature proxies from the natural climate system and time series of nonlinear model system are used in understanding the natural climate change and recognizing potential benefits by using the method of wavelet transform analysis. The results from numerical modeling show that major oscillations contained in numerical solutions on the interdecadal timescale are consistent with that of natural proxies. It seems that these oscillations in the climate change are not directly linked with the solar radiation as an external forcing. This investigation may conclude that the climate variability at the interdecadal timescale strongly depends on the internal nonlinear effects in the climate system.

  19. Incorporating climate change trends to near future variability of crop yields in Iberia Peninsula

    Science.gov (United States)

    Capa-Morocho, Mirian; Baethgen, Walter E.; Fernandes, Kátia; Rodríguez-Fonseca, Belén; Ruiz-Ramos, Margarita

    2016-04-01

    In this study, we analyze the effects of near future climate variability on cropping systems in Iberian Peninsula (IP). For this purpose, we generated climate sequences that simulate realistic variability on annual to decadal time scales. The sequences incorporate nonlinear climate change trends, using statistical methods and and an ensemble of global climate models from the Coupled Model Intercomparison Project (CMIP5). Then, the climate sequences are temporal downscaled into daily weather data and used as inputs to crop models. As case study, we evaluate the impacts of plausible future climate scenarios on rain-fed wheat yield two agricultural locations in IP. We adapted the method by Greene et al., (2012 and 2015) for informing climate projections for the coming decades with a combination of seasonal to interannual and anthropogenically forced climate change information for accounting the Near-term Climate Change. Long-term data containing solar radiation, maximum and minimum temperature and rainfall are needed to apply this method. The climate variability observed was decomposed into long-range trend, decadal and interannual variability to understand the relative importance of each time scale. The interannual variability was modeled based on the observational records. The results of this study may have important implications on public and private sectors to analyze the probabilistic projections of impacts and agronomic adaptations of near future climate variability in Iberian Peninsula. This study has been funded by MACSUR project from FACCE-JPI. References Greene, A.M., Goddard, L., Gonzalez, P.L., Ines, A.V. and Chryssanthacopoulos, J., 2015.A climate generator for agricultural planning in southeastern South America.Agricultural and Forest Meteorology, 203: 217-228. Greene, A.M., Hellmuth, M. and Lumsden, T., 2012. Stochastic decadal climate simulations for the Berg and Breede water management areas, western Cape province, South Africa. Water Resources

  20. Break and trend analysis of EUMETSAT Climate Data Records

    Science.gov (United States)

    Doutriaux-Boucher, Marie; Zeder, Joel; Lattanzio, Alessio; Khlystova, Iryna; Graw, Kathrin

    2016-04-01

    EUMETSAT reprocessed imagery acquired by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on board Meteosat 8-9. The data covers the period from 2004 to 2012. Climate Data Records (CDRs) of atmospheric parameters such as Atmospheric Motion Vectors (AMV) as well as Clear and All Sky Radiances (CSR and ASR) have been generated. Such CDRs are mainly ingested by ECMWF to produce a reanalysis data. In addition, EUMETSAT produced a long CDR (1982-2004) of land surface albedo exploiting imagery acquired by the Meteosat Visible and Infrared Imager (MVIRI) on board Meteosat 2-7. Such CDR is key information in climate analysis and climate models. Extensive validation has been performed for the surface albedo record and a first validation of the winds and clear sky radiances have been done. All validation results demonstrated that the time series of all parameter appear homogeneous at first sight. Statistical science offers a variety of analyses methods that have been applied to further analyse the homogeneity of the CDRs. Many breakpoint analysis techniques depend on the comparison of two time series which incorporates the issue that both may have breakpoints. This paper will present a quantitative and statistical analysis of eventual breakpoints found in the MVIRI and SEVIRI CDRs that includes attribution of breakpoints to changes of instruments and other events in the data series compared. The value of different methods applied will be discussed with suggestions how to further develop this type of analysis for quality evaluation of CDRs.

  1. Earliest local emergence of forced dynamic and steric sea-level trends in climate models

    International Nuclear Information System (INIS)

    We investigate the impact of internal variability on the emergence of a forced local trend in steric and dynamic sea surface height in historical and future climate simulations. By analyzing the unforced control simulations, the magnitude of internally generated, local trends in sea surface height is quantified and compared to trends found in historical simulations and projections. We find that the timing of the emergence of a forced local signal depends strongly on the location and the year in which the trend computations are started. Starting in 1950, it takes at least 60 yr to detect a forced trend in regions of weak internal variability such as the tropical Atlantic Ocean while this period is reduced to 30 yr when starting in 1990. The detection of a forced trend is further delayed by several decades in regions of elevated internal variability. (letter)

  2. Impacts of the superimposed climate trends on droughts over 1961-2013 in Xinjiang, China

    Science.gov (United States)

    Li, Yi; Sun, Changfeng

    2016-05-01

    This study reveals the impacts of climatic variable trends on drought severity in Xinjiang, China. Four drought indices, including the self-calibrating Palmer drought severity index (sc-PDSI), Erinç's index (I m), Sahin's index (I sh), and UNEP aridity index (AI), were used to compare drought severity. The ensemble empirical mode decomposition and the modified Mann-Kendall trend test were applied to analyze the nonlinear components and trends of the climatic variable and drought indices. Four and six climatic scenarios were generated in sc-PDSI, I m, I sh, and AI with different combinations of the observed and detrended climatic variables, respectively. In Xinjiang, generally increasing trends in minimal, average, and maximal air temperature (T min, T ave, T max) and precipitation (P) were found, whereas a decreasing trend in wind speed at 2 m height (U 2) was observed. There were significantly increasing trends in all of the four studied drought indices. Drought relief was more obvious in northern Xinjiang than in southern Xinjiang. The strong influences of increased P on drought relief and the weak influences of increased T min, T ave, and T max on drought aggravation were shown by comparing four drought indices under different climate scenarios. Decreased U 2 had a weak influence on drought, as shown by the AI in different climate scenarios. The weak influences of T and U 2 were considered to be masked by the strong influences of P on droughts. Droughts were expected to be more severe if P did not increase, but were likely milder without an increase in air temperature and with a decrease in U 2.

  3. Spatial patterns and recent trends in the climate of tropical rainforest regions.

    OpenAIRE

    Malhi, Yadvinder; Wright, James

    2004-01-01

    We present an analysis of the mean climate and climatic trends of tropical rainforest regions over the period 1960-1998, with the aid of explicit maps of forest cover and climatological databases. Until the mid-1970s most regions showed little trend in temperature, and the western Amazon experienced a net cooling probably associated with an interdecadal oscillation. Since the mid-1970s, all tropical rainforest regions have experienced a strong warming at a mean rate of 0.26 +/- 0.05 degrees C...

  4. Trends of climatic changes considering over years 1894-1993 and 1894-2003 for Sarajevo

    International Nuclear Information System (INIS)

    Linear trends of changes in climatic parameters have been observed for Sarajevo and we considered correlation with world's trends and mutual correlation of years .1894-1993 and 1894-2003, both for the same meteorological station Sarajevo. In purpose of ascertaining correlation with global climate's changes, Sarajevo's records have been studied over the primary climatic parameters: average annual temperatures, absolute annual maximum and minimum temperatures, annual sum of rainfalls and drought index. We used method of adding of linear trends. Correlation with global tendency of climate has be shown as follow: - We notice increase of average temperature about 0.7oC in past 100 years - We notice a rapid increase of absolute minimum temperature in compare with values of absolute maximum temperatures. - Annual sum of rainfalls doesn't show drastic changes. - We notice asymmetry trend for some actual seasons. - We notice increase of drought. During correlation of trends for years 1894-1993 and 1894-2003 has been noticed rapid increase of temperature and drought-index, while considering rainfalls there has not been drastic changes. (Author)

  5. Individual contributions of climate and vegetation change to soil moisture trends across multiple spatial scales

    Science.gov (United States)

    Feng, Huihui

    2016-01-01

    Climate and vegetation change are two dominating factors for soil moisture trend. However, their individual contributions remain unknown due to their complex interaction. Here, I separated their contributions through a trajectory-based method across the global, regional and local scales. Our results demonstrated that climate change accounted for 98.78% and 114.64% of the global drying and wetting trend. Vegetation change exhibited a relatively weak influence (contributing 1.22% and −14.64% of the global drying and wetting) because it occurred in a limited area on land. Regionally, the impact of vegetation change cannot be neglected, which contributed −40.21% of the soil moisture change in the wetting zone. Locally, the contributions strongly correlated to the local environmental characteristics. Vegetation negatively affected soil moisture trends in the dry and sparsely vegetated regions and positively in the wet and densely vegetated regions. I conclude that individual contributions of climate and vegetation change vary at the global, regional and local scales. Climate change dominates the soil moisture trends, while vegetation change acts as a regulator to drying or wetting the soil under the changing climate. PMID:27600157

  6. Individual contributions of climate and vegetation change to soil moisture trends across multiple spatial scales.

    Science.gov (United States)

    Feng, Huihui

    2016-01-01

    Climate and vegetation change are two dominating factors for soil moisture trend. However, their individual contributions remain unknown due to their complex interaction. Here, I separated their contributions through a trajectory-based method across the global, regional and local scales. Our results demonstrated that climate change accounted for 98.78% and 114.64% of the global drying and wetting trend. Vegetation change exhibited a relatively weak influence (contributing 1.22% and -14.64% of the global drying and wetting) because it occurred in a limited area on land. Regionally, the impact of vegetation change cannot be neglected, which contributed -40.21% of the soil moisture change in the wetting zone. Locally, the contributions strongly correlated to the local environmental characteristics. Vegetation negatively affected soil moisture trends in the dry and sparsely vegetated regions and positively in the wet and densely vegetated regions. I conclude that individual contributions of climate and vegetation change vary at the global, regional and local scales. Climate change dominates the soil moisture trends, while vegetation change acts as a regulator to drying or wetting the soil under the changing climate. PMID:27600157

  7. Paleocene initiation of cenozoic uplift in Norway

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, S.B.; Paulsen, G.E.; Hansen, D.L.; Gemmer, L.; Clausen, O.R.; Jacobsen, B.H.; Balling, N.; Huuse, M.; Gallagher, K.

    2003-12-01

    The timing of Cenozoic surface uplift in NW Europe relies on the assumption that the sedimentary response in basins is synchronous with tectonic processes in the source areas. However, many of the phenomena commonly used to infer recent uplift may as well be a consequence of climate change and sea-level fall. The timing of surface uplift therefore remains unconstrained from the sedimentary record alone, and it becomes necessary to consider the constraints imposed by physically and geologically plausible tectonic mechanisms, which have a causal relation to an initiating agent. The gradual reversal of the regional stress field following the break-up produced minor perturbations to the thermal subsidence on the Norwegian Shelf and in the North Sea. Pulses of increased compression cannot be the cause of Cenozoic land surface uplift and accelerated Neogene basin subsidence. Virtually deformation-free regional vertical movements could have been caused by changes in the density column of the lithosphere and asthenosphere following the emplacement of the Iceland plume. A transient uplift component was produced as the plume displaced denser asthenosphere at the base of the lithosphere. This component decayed as the plume material cooled. Permanent uplift as a result of igneous underplating occurred in areas of a thin lithosphere (some Palaeozoic and Mesozoic basins) or for lithosphere under extension at the time of plume emplacement (the ocean-continent boundary). In areas of a thicker lithosphere (East Greenland, Scotland and Norway) plume emplacement may have triggered a Rayleigh-Taylor instability, causing partial lithospheric delamination and associated transient surface uplift at a decreasing rate throughout Cenozoic time. A possible uplift history for the adjacent land areas hence reads: initial transient surface uplift around the break-up time at 53 Ma caused by plume emplacement, and permanent tectonic uplift caused by lithospheric delamination and associated

  8. Bird population trends are linearly affected by climate change along species thermal ranges

    OpenAIRE

    Jiguet, Frédéric; Devictor, Vincent; Ottvall, Richard; Van Turnhout, Chris; van der Jeugd, Henk; Lindström, Åke

    2010-01-01

    Beyond the effects of temperature increase on local population trends and on species distribution shifts, how populations of a given species are affected by climate change along a species range is still unclear. We tested whether and how species responses to climate change are related to the populations locations within the species thermal range. We compared the average 20 year growth rates of 62 terrestrial breeding birds in three European countries along the latitudinal gradient of the spec...

  9. Impacts of climate change on plant diseases – opinions and trends

    OpenAIRE

    Pautasso, Marco; Döring, Thomas F.; Garbelotto, M.; Pellis, L.; Jeger, MJ

    2012-01-01

    There has been a remarkable scientific output on the topic of how climate change is likely to affect plant diseases in the coming decades. This review addresses the need for review of this burgeoning literature by summarizing opinions of previous reviews and trends in recent studies on the impacts of climate change on plant health. Sudden Oak Death is used as an introductory case study: Californian forests could become even more susceptible to this emerging plant disease, if spring precipitat...

  10. Evaluating historical climate and hydrologic trends in the Central Appalachian region of the United States

    Science.gov (United States)

    Gaertner, B. A.; Zegre, N.

    2015-12-01

    Climate change is surfacing as one of the most important environmental and social issues of the 21st century. Over the last 100 years, observations show increasing trends in global temperatures and intensity and frequency of precipitation events such as flooding, drought, and extreme storms. Global circulation models (GCM) show similar trends for historic and future climate indicators, albeit with geographic and topographic variability at regional and local scale. In order to assess the utility of GCM projections for hydrologic modeling, it is important to quantify how robust GCM outputs are compared to robust historical observations at finer spatial scales. Previous research in the United States has primarily focused on the Western and Northeastern regions due to dominance of snow melt for runoff and aquifer recharge but the impact of climate warming in the mountainous central Appalachian Region is poorly understood. In this research, we assess the performance of GCM-generated historical climate compared to historical observations primarily in the context of forcing data for macro-scale hydrologic modeling. Our results show significant spatial heterogeneity of modeled climate indices when compared to observational trends at the watershed scale. Observational data is showing considerable variability within maximum temperature and precipitation trends, with consistent increases in minimum temperature. The geographic, temperature, and complex topographic gradient throughout the central Appalachian region is likely the contributing factor in temperature and precipitation variability. Variable climate changes are leading to more severe and frequent climate events such as temperature extremes and storm events, which can have significant impacts on our drinking water supply, infrastructure, and health of all downstream communities.

  11. Assessing trends in observed and modelled climate extremes over Australia in relation to future projections

    International Nuclear Information System (INIS)

    Full text: Nine global coupled climate models were assessed for their ability to reproduce observed trends in a set of indices representing temperature and precipitation extremes over Australia. Observed trends for 1957-1999 were compared with individual and multi-modelled trends calculated over the same period. When averaged across Australia the magnitude of trends and interannual variability of temperature extremes were well simulated by most models, particularly for the warm nights index. Except for consecutive dry days, the majority of models also reproduced the correct sign of trend for precipitation extremes. A bootstrapping technique was used to show that most models produce plausible trends when averaged over Australia, although only heavy precipitation days simulated from the multi-model ensemble showed significant skill at reproducing the observed spatial pattern of trends. Two of the models with output from different forcings showed that only with anthropogenic forcing included could the models capture the observed areally averaged trend for some of the temperature indices, but the forcing made little difference to the models' ability to reproduce the spatial pattern of trends over Australia. Future projected changes in extremes using three emissions scenarios were also analysed. Australia shows a shift towards significant warming of temperature extremes with much longer dry spells interspersed with periods of increased extreme precipitation irrespective of the scenario used. More work is required to determine whether regional projected changes over Australia are robust

  12. Impacts of Climate Trends and Variability on Livestock Production in Brazil

    Science.gov (United States)

    Cohn, A.; Munger, J.; Gibbs, H.

    2015-12-01

    Cattle systems of Brazil are of major economic and environmental importance. They occupy ¼ of the land surface of the country, account for over 15 billion USD of annual revenue through the sale of beef, leather, and milk, are closely associated with deforestation, and have been projected to substantially grow in the coming decades. Sustainable intensification of production in the sector could help to limit environmental harm from increased production, but productivity growth could be inhibited by climate change. Gauging the potential future impacts of climate change on the Brazilian livestock sector can be aided by examining past evidence of the link between climate and cattle production and productivity. We use statistical techniques to investigate the contribution of climate variability and climate change to variability in cattle system output in Brazil's municipalities over the period 1974 to 2013. We find significant impacts of both temperature and precipitation variability and temperature trends on municipality-level exports and the production of both milk and beef. Pasture productivity, represented by a vegetation index, also varies significantly with climate shocks. In some regions, losses from exposure to climate trends were of comparable magnitude to technology and/or market-driven productivity gains over the study period.

  13. Trends in marine climate change research in the Nordic region since the first IPCC report

    DEFF Research Database (Denmark)

    Pedersen, Martin Wæver; Kokkalis, Alexandros; Bardarson, H.;

    2016-01-01

    across disciplines. For climate change related problems these research directions have been well-established since the publication of the first IPCC report in 1990, however it is not well-documented to what extent these directions are reflected in published research. Focusing on the Nordic region, we...... evaluated the development of climate change related marine science by quantifying trends in number of publications, disciplinarity, and scientific focus of 1362 research articles published between 1990 and 2011. Our analysis showed a faster increase in publications within climate change related marine...... science than in general marine science indicating a growing prioritisation of research with a climate change focus. The composition of scientific disciplines producing climate change related publications, which initially was dominated by physical sciences, shifted toward a distribution with almost even...

  14. Impacts of recent climate change on Wisconsin corn and soybean yield trends

    International Nuclear Information System (INIS)

    The US Corn Belt supports agroecosystems that flourish in a temperate climate regime that could see significant changes in the next few decades. Because Wisconsin is situated on the northern, cooler fringes of this region, it may be the beneficiary of a warmer climate that could help support higher corn and soybean yields. Here we show that trends in precipitation and temperature during the growing season from 1976-2006 explained 40% and 35% of county corn and soybean yield trends, respectively. Using county level yield information combined with climate data, we determined that both corn and soybean yield trends were enhanced in counties that experienced a trend towards cooler and wetter conditions during the summer. Our results suggest that for each additional degree (deg. C) of future warming during summer months, corn and soybean yields could potentially decrease by 13% and 16%, respectively, whereas if modest increases in total summer precipitation (i.e. 50 mm) were to occur, yields may be boosted by 5-10%, counteracting a portion of the negative effects associated with increased temperature. While northern US Corn Belt regions such as Wisconsin may benefit from a warmer climate regime and management changes that lengthen the crop-growing period in spring and autumn, mid- to high-latitude crop productivity may be challenged by additional summertime warming unless adaptive measures are taken

  15. Mesosphere-Stratosphere Coupling: Implications for Climate Variability and Trends

    Science.gov (United States)

    Baldwin, Mark P.

    2004-01-01

    A key aspect of this project is the establishment of a causal link from circulation anomalies in the lower mesosphere and stratopause region downward through the stratosphere to the troposphere. The observational link for stratospheric sudden warmings and surface climate is fairly clear. However, our understanding of the dynamics is incomplete. We have been making significant progress in the area of dynamical mechanisms by which circulation anomalies in the stratosphere affect the troposphere. We are trying to understand the details and sequence of events that occur when a middle atmosphere (wind) anomaly propagates downward to near the tropopause. The wind anomaly could be caused by a warming or solar variations in the low-latitude stratopause region, or could have other causes. The observations show a picture that is consistent with a circulation anomaly that descends to the tropopause region, and can be detected as low as the mid-troposphere. Processes near the stratopause in the tropics appear to be important precursors to the wintertime development of the northern polar vortex. This may affect significantly our understanding of the process by which low-latitude wind anomalies in the low mesosphere and upper stratosphere evolve through the winter and affect the polar vortex.

  16. Climate change in Inner Mongolia from 1955 to 2005-trends at regional, biome and local scales

    International Nuclear Information System (INIS)

    This study investigated the climate change in Inner Mongolia based on 51 meteorological stations from 1955 to 2005. The climate data was analyzed at the regional, biome (i.e. forest, grassland and desert) and station scales, with the biome scale as our primary focus. The climate records showed trends of warmer and drier conditions in the region. The annual daily mean, maximum and minimum temperature increased whereas the diurnal temperature range (DTR) decreased. The decreasing trend of annual precipitation was not significant. However, the vapor pressure deficit (VPD) increased significantly. On the decadal scale, the warming and drying trends were more significant in the last 30 years than the preceding 20 years. The climate change varied among biomes, with more pronounced changes in the grassland and the desert biomes than in the forest biome. DTR and VPD showed the clearest inter-biome gradient from the lowest rate of change in the forest biome to the highest rate of change in the desert biome. The rates of change also showed large variations among the individual stations. Our findings correspond with the IPCC predictions that the future climate will vary significantly by location and through time, suggesting that adaptation strategies also need to be spatially viable.

  17. Late Cenozoic fire enhancement response to aridification in mid-latitude Asia: Evidence from microcharcoal records

    Science.gov (United States)

    Miao, Yunfa; Fang, Xiaomin; Song, Chunhui; Yan, Xiaoli; Zhang, Ping; Meng, Qingquan; Li, Fang; Wu, Fuli; Yang, Shengli; Kang, Shuyuan; Wang, Yuanping

    2016-05-01

    Fire provides an important indicator of paleoclimatic change. However, little information relating to late Cenozoic fire history has been gathered in mid-latitude Asia (including Inner Asia and East Asia), a key region for understanding the development of the arid-monsoon climate system as well as the driving forces behind it. Here we first report the records of microcharcoal concentrations (MC) covering the Holocene (10-0 ka) and late Pleistocene (0.8-0 Ma), which we use to analyze the fire activity patterns at an orbital time scale; then we compile the late Cenozoic MC record to investigate the long-term fire history by analyzing four cores from the Yangtze River Delta (YRD) area, East Asia (representing 8-0 Ma) and three sites in Inner Asia (representing 18-2 Ma). The results show that the (i) MC remained higher during the relatively dry late Holocene/glacial stages than that during the humid middle Holocene/interglacial stages at individual sites; (ii) MC increased with time in both Inner Asia and East Asia after 18 and 8 Ma, respectively; and (iii) MC always remained higher in the dry Inner Asia than in the contemporaneous wet East Asia. All these characteristics imply that late Cenozoic fire occurrence in mid-latitude Asia experienced a gradual increasing trend along with the global temperature/ice volume change, and indicates a continuous aridification trend across mid-latitude Asia. The global cooling, rather than the Tibetan Plateau uplift, might have played a key role in this observed trend.

  18. Prevailing climatic trends and runoff response from Hindukush-Karakoram-Himalaya, upper Indus basin

    CERN Document Server

    Hasson, Shabeh ul; Lucarini, Valerio

    2015-01-01

    We analyze trends in maximum, minimum and mean temperatures (Tx, Tn, and Tavg, respectively), diurnal temperature range (DTR) and precipitation from 18 stations (1250-4500 m asl) for their overlapping period of record (1995-2012), and separately, from six stations of their long term record (1961-2012). We apply Mann-Kendall test on serially independent time series to assess existence of a trend while true slope is estimated using Sen s slope method. Further, we statistically assess the spatial scale (field) significance of local climatic trends within ten identified sub-regions of UIB and analyze whether the spatially significant (field significant) climatic trends qualitatively agree with a trend in discharge out of corresponding sub-region. Over the recent period (1995-2012), we find a well agreed and mostly field significant cooling (warming) during monsoon season i.e. July-October (March-May and November), which is higher in magnitude relative to long term trends (1961-2012). We also find ... The observed...

  19. 温盐环流反转及其对新生代气候的影响%TRANSITION OF THERMOHALINE CIRCULATION MODES AND ITS IMPACT ON CENOZOIC CLIMATE

    Institute of Scientific and Technical Information of China (English)

    张仲石; 王会军; 郭正堂

    2009-01-01

    温盐环流是由海水温度、盐度差异驱动的全球洋流循环系统.在气候系统中,它对全球热量输送起到了十分重要的作用.在亚轨道尺度(千年时间尺度)上,温盐环流的改变导致了一系列快速的气候变化,因此备受关注.在构造时间尺度(百万年时间尺度)上,古海洋记录和数值模拟揭示出,温盐环流的反转对新生代气候也产生了非常显著的影响.在新生代,温盐环流由"南大洋深层水主控型"向"北大西洋深层水主控型"反转.这一反转改变了全球的热量输送,使得南半球强烈变冷,并有町能导致南极东部永久冰盖的形成.在这一反转事件中,热带海道的作用更加重要.%The thermohaline circulation(THC)is a large-scale ocean circulation driven by global density gradients created by surface heat and freshwater fluxes. It plays an important role in the globale heat transport. Changes of the circulation have large impacts on the Earth climate. They cause a series of abrupt climate variations on the sub-orbital time scale, I. E., the millennial scale. Thus, the thermohaline circulation receives much concern. Here, based on paleoceanographic evidence and numeral modeling, we show that the thermohaline circulation also affect the climate markedly on the tectonic time scale,I, e., the million-year scale. In the Cenozoic,the thermohaline circulation reversed from the southern ocean deep water(SODW) dominated mode to the North Atlantic deep water(NADW) dominated mode,though the time of this reversal is still under debates. Some evidence reveals that the NADW formation was active during a period of the late Early Miocene and dominated ocean circulation after about 15Ma,while the earliest evidence of the NADW formation has been found in deep sea cores of the Early Oligocene age. The recent modeling study simulated the transition of thermohaline circulation from the SODW to the NADW dominated mode. The simulation indicates that the

  20. Spatial variability of the trends in climatic variables across China during 1961-2010

    Science.gov (United States)

    Yang, Hanbo; Yang, Dawen; Hu, Qingfang; Lv, Huafang

    2015-05-01

    Distribution of meteorological stations is not uniform in many regions of the world, especially in developing countries like China. To eliminate the effect of uneven stations, this study produced a data set of areal average precipitation, air temperature, solar radiation, and wind speed from 736 meteorological station observations during 1961-2010 using an inverse-distance weighted technique. Based on the data set, this study detected the trends in climatic variables. Precipitation has a slight but no significant ( p = 0.78) trend for the whole of China and has a significant increase trend in northwest China. Surface air temperature has a significant ( p < 0.001) accelerating warming trend of 0.032 °C/a for the whole of China, and spatially larger in northern China than that in southern China. Solar radiation has a significant ( p < 0.001) dimming trend of -0.14 W/(m2 · a) for the whole of China, and the largest dimming trend appears in eastern China, the possible cause for which is a high-aerosol concentration. Surface wind speed has a significant ( p < 0.001) stilling trend of -0.012 m/(s·a) for the whole of China, the causes for which were speculated the changes in atmospheric circulation and surface roughness, as well as increases in aerosol concentration and the decrease in the south-north temperature gradient in China. In addition, three large-scale instrument replacements increase uncertainties of the trend analysis.

  1. Trends In Wintertime Climate Variability In The Northeastern United States: 1970- 2004

    Science.gov (United States)

    Burakowski, E. A.; Wake, C. P.; Braswell, B.

    2007-12-01

    Humans experience climate variability and climate change primarily through changes in weather at a local and regional scale. One of the most effective means to track these changes is through detailed analysis of meteorological data. In this work, changes in the winter climate of the northeastern United States are documented. Snow on the ground and snowfall are important components in water management, travel safety, and winter tourism and recreation. Trends in Temperature, snowfall, and snow depth data were collected from the United States Historical Climate Network (USHCN). The months of December through March are selected for winter climate analysis. Monthly and seasonal time series of the number of days with snow on the ground greater than 1, 3, and 5 inches are constructed from snow depth data. The National Climatic Data Center and Carbon Dioxide Information Analysis Center perform extensive quality assurance and quality control measures for monthly temperature data. However, daily snowfall and snow depth data have not been adjusted for station relocations, instrument changes, or time of observation biases. To address these data quality issues, we evaluate daily data for spatial coherence with nearest neighbors, and remove stations with non-climatic influences from regional analysis. Monthly and seasonal trends in mean, minimum and maximum temperature, total snowfall, and days with snow on the ground are estimated using linear regression and robust spline analysis. Northeastern United States winter temperatures are warming at a rate significantly greater than the global average. At stations located north of 44oN, December snowfall exhibits a decreasing trend (-3.5 inches/decade), whereas March snowfall is increasing (+1.3 inches/decade) over the period 1970-2004. Across the northeastern United States, the number of days with snow on the ground has also decreased substantially. The results hold important implications for the winter economy and recreation in the

  2. Cenozoic stratigraphy of the Sahara, Northern Africa

    Science.gov (United States)

    Swezey, Christopher S.

    2009-01-01

    This paper presents an overview of the Cenozoic stratigraphic record in the Sahara, and shows that the strata display some remarkably similar characteristics across much of the region. In fact, some lithologies of certain ages are exceptionally widespread and persistent, and many of the changes from one lithology to another appear to have been relatively synchronous across the Sahara. The general stratigraphic succession is that of a transition from early Cenozoic carbonate strata to late Cenozoic siliciclastic strata. This transition in lithology coincides with a long-term eustatic fall in sea level since the middle Cretaceous and with a global climate transition from a Late Cretaceous–Early Eocene “warm mode” to a Late Eocene–Quaternary “cool mode”. Much of the shorter-term stratigraphic variability in the Sahara (and even the regional unconformities) also can be correlated with specific changes in sea level, climate, and tectonic activity during the Cenozoic. Specifically, Paleocene and Eocene carbonate strata and phosphate are suggestive of a warm and humid climate, whereas latest Eocene evaporitic strata (and an end-Eocene regional unconformity) are correlated with a eustatic fall in sea level, the build-up of ice in Antarctica, and the appearance of relatively arid climates in the Sahara. The absence of Oligocene strata throughout much of the Sahara is attributed to the effects of generally low eustatic sea level during the Oligocene and tectonic uplift in certain areas during the Late Eocene and Oligocene. Miocene sandstone and conglomerate are attributed to the effects of continued tectonic uplift around the Sahara, generally low eustatic sea level, and enough rainfall to support the development of extensive fluvial systems. Middle–Upper Miocene carbonate strata accumulated in northern Libya in response to a eustatic rise in sea level, whereas Upper Miocene mudstone accumulated along the south side of the Atlas Mountains because uplift of the

  3. Land-atmosphere coupling explains the link between pan evaporation and actual evapotranspiration trends in a changing climate

    NARCIS (Netherlands)

    Heerwaarden, van C.C.; Vilà-Guerau de Arellano, J.; Teuling, A.J.

    2010-01-01

    Decreasing trends in pan evaporation are widely observed across the world as a response of the climate system to changes in temperature, precipitation, incoming radiation and wind speed. Nevertheless, we only partially understand how trends in actual evapotranspiration are linked to those trends. He

  4. Long-Term Trends and Role of Climate in the Population Dynamics of Eurasian Reindeer

    Science.gov (United States)

    Horstkotte, Tim; Kaarlejärvi, Elina; Sévêque, Anthony; Stammler, Florian; Olofsson, Johan; Forbes, Bruce C.; Moen, Jon

    2016-01-01

    Temperature is increasing in Arctic and sub-Arctic regions at a higher rate than anywhere else in the world. The frequency and nature of precipitation events are also predicted to change in the future. These changes in climate are expected, together with increasing human pressures, to have significant impacts on Arctic and sub-Arctic species and ecosystems. Due to the key role that reindeer play in those ecosystems, it is essential to understand how climate will affect the region’s most important species. Our study assesses the role of climate on the dynamics of fourteen Eurasian reindeer (Rangifer tarandus) populations, using for the first time data on reindeer abundance collected over a 70-year period, including both wild and semi-domesticated reindeer, and covering more than half of the species’ total range. We analyzed trends in population dynamics, investigated synchrony among population growth rates, and assessed the effects of climate on population growth rates. Trends in the population dynamics were remarkably heterogeneous. Synchrony was apparent only among some populations and was not correlated with distance among population ranges. Proxies of climate variability mostly failed to explain population growth rates and synchrony. For both wild and semi-domesticated populations, local weather, biotic pressures, loss of habitat and human disturbances appear to have been more important drivers of reindeer population dynamics than climate. In semi-domesticated populations, management strategies may have masked the effects of climate. Conservation efforts should aim to mitigate human disturbances, which could exacerbate the potentially negative effects of climate change on reindeer populations in the future. Special protection and support should be granted to those semi-domesticated populations that suffered the most because of the collapse of the Soviet Union, in order to protect the livelihood of indigenous peoples that depend on the species, and the multi

  5. Long-Term Trends and Role of Climate in the Population Dynamics of Eurasian Reindeer.

    Science.gov (United States)

    Uboni, Alessia; Horstkotte, Tim; Kaarlejärvi, Elina; Sévêque, Anthony; Stammler, Florian; Olofsson, Johan; Forbes, Bruce C; Moen, Jon

    2016-01-01

    Temperature is increasing in Arctic and sub-Arctic regions at a higher rate than anywhere else in the world. The frequency and nature of precipitation events are also predicted to change in the future. These changes in climate are expected, together with increasing human pressures, to have significant impacts on Arctic and sub-Arctic species and ecosystems. Due to the key role that reindeer play in those ecosystems, it is essential to understand how climate will affect the region's most important species. Our study assesses the role of climate on the dynamics of fourteen Eurasian reindeer (Rangifer tarandus) populations, using for the first time data on reindeer abundance collected over a 70-year period, including both wild and semi-domesticated reindeer, and covering more than half of the species' total range. We analyzed trends in population dynamics, investigated synchrony among population growth rates, and assessed the effects of climate on population growth rates. Trends in the population dynamics were remarkably heterogeneous. Synchrony was apparent only among some populations and was not correlated with distance among population ranges. Proxies of climate variability mostly failed to explain population growth rates and synchrony. For both wild and semi-domesticated populations, local weather, biotic pressures, loss of habitat and human disturbances appear to have been more important drivers of reindeer population dynamics than climate. In semi-domesticated populations, management strategies may have masked the effects of climate. Conservation efforts should aim to mitigate human disturbances, which could exacerbate the potentially negative effects of climate change on reindeer populations in the future. Special protection and support should be granted to those semi-domesticated populations that suffered the most because of the collapse of the Soviet Union, in order to protect the livelihood of indigenous peoples that depend on the species, and the multi

  6. PATMOS-x Cloud Climate Record Trend Sensitivity to Reanalysis Products

    Directory of Open Access Journals (Sweden)

    Michael J. Foster

    2016-05-01

    Full Text Available Continuous satellite-derived cloud records now extend over three decades, and are increasingly used for climate applications. Certain applications, such as trend detection, require a clear understanding of uncertainty as it relates to establishing statistical significance. The use of reanalysis products as sources of ancillary data could be construed as one such source of uncertainty, as there has been discussion regarding the suitability of reanalysis products for trend detection. Here we use three reanalysis products: Climate Forecast System Reanalysis (CFSR, Modern Era Retrospective Analysis for Research and Applications (MERRA and European Center for Medium range Weather Forecasting (ECMWF ERA-Interim (ERA-I as sources of ancillary data for the Pathfinder Atmospheres Extended/Advanced Very High Resolution Radiometer (PATMOS-x/AVHRR Satellite Cloud Climate Data Record (CDR, and perform inter-comparisons to determine how sensitive the climatology is to choice of ancillary data source. We find differences among reanalysis fields required for PATMOS-x processing, which translate to small but not insignificant differences in retrievals of cloud fraction, cloud top height and cloud optical depth. The retrieval variability due to choice of reanalysis product is on the order of one third the size of the retrieval uncertainty, making it a potentially significant factor in trend detection. Cloud fraction trends were impacted the most by choice of reanalysis while cloud optical depth trends were impacted the least. Metrics used to determine the skill of the reanalysis products for use as ancillary data found no clear best choice for use in PATMOS-x. We conclude use of reanalysis products as ancillary data in the PATMOS-x/AVHRR Cloud CDR do not preclude its use for trend detection, but for that application uncertainty in reanalysis fields should be better represented in the PATMOS-x retrieval uncertainty.

  7. Climatic trends in the Amazonian area of Ecuador: Classical and multifractal analyses

    Science.gov (United States)

    Millán, H.; Kalauzi, A.; Llerena, G.; Sucoshañay, J.; Piedra, D.

    The climate evolution and change in the Amazonian area is very important at least at a continental scale involving Latin America where more than 550 million people live. The objective of the present study was to investigate, from an environmental perspective, the climatic trends in the Amazonian area of continental Ecuador. We performed both classical and multifractal analyses of these trends on four climatic variables (maximum and minimum temperature, evaporation and evaporation/precipitation ratio). Data were collected from Puyo meteorological station, Pastaza Province, Ecuador. Data sets covered 31 years (from January 1974 to September 2005). Each time series consisted of 380 months. Piecewise regression analyses with breaking point showed two regimes with a cutoff ranging from t = 80 months (maximum and minimum temperature) to t = 133 months for the evaporation pattern (determination coefficient ≥ 0.979) while the multifractal analyses showed an increasing complexity within each climatic variable. All the considered climatic variables showed an increase since 1974 to approximately 1985. After that some type of smoother increase was observed.

  8. Relationships of pinon juniper woodland expansion and climate trends in the Walker Basin, Nevada

    Science.gov (United States)

    Donald, Jonathon

    Landscapes are in constant flux. Vegetation distributions have changed in conjunction with climate, driven by factors such as Milankovitch cycles and atmospheric composition. Until recently, these changes have occurred gradually. Human populations are altering Earth's systems, including atmospheric composition and land use. This is altering vegetation distributions at landscape scales due to changes in species potential niche, as well as current and historical alteration of their realized niche. Vegetation shifts have the potential to be more pronounced in arid and mountainous environments as resources available to plants such as soil moisture are more limiting. In the Great Basin physiographic region of the western United States, woody encroachment of pinon juniper (Pinus monophylla & Juniperus osteosperma) woodlands is well known, but the drivers of its expansion are not well understood across elevational gradients. Predominant theories of future vegetation distribution change due to a changing climate, predict that montane species will move upslope in response to increasing temperatures. In pinon juniper woodlands, the focus has been on downslope movement of woodlands into other ecosystem types. The drivers for this are typically thought to be historical land uses such as grazing and fire exclusion. However, infilling and establishment is occurring throughout its distribution and relatively little attention has been paid to woodland movement uphill. This study focuses on two mountain ranges within the Walker Lake Basin, so as to understand changes occurring along the full gradient of pinon juniper woodlands, from lower to upper treeline, on both the western and eastern side of the ranges. The overall goal of this study was to understand trends of change (increasing, decreasing canopy density) in pinon juniper woodlands and determine if these trends were related to climate change trends. Trends in both vegetation and climate were analyzed for the entire

  9. Response of Agriculture and Forests to Climate Change in France: Assessment of Uncertainties and Trend Analysis

    Science.gov (United States)

    Laanaia, N.; Carrer, D.

    2014-12-01

    In the framework of the French research project ORACLE we examine the impact of climate change on agriculture and forests in France for two time horizons (2020-2050 and 2070-2100) in reference to the 1970-2000 period. The biophysical variables (leaf area index, equilibrium forest biomass, leaf onset and offset, ...) are produced by ISBA-A-gs forced by the atmospheric variables produced by differents climat models and scenarios. Their trends will be analyzed. The impact of uncertainties at various levels through multi-model and multi-scenario approaches will be assessed

  10. Temporal trend and climate factors of hemorrhagic fever with renal syndrome epidemic in Shenyang City, China

    Directory of Open Access Journals (Sweden)

    Liu Xiaodong

    2011-12-01

    Full Text Available Abstract Background Hemorrhagic fever with renal syndrome (HFRS is an important infectious disease caused by different species of hantaviruses. As a rodent-borne disease with a seasonal distribution, external environmental factors including climate factors may play a significant role in its transmission. The city of Shenyang is one of the most seriously endemic areas for HFRS. Here, we characterized the dynamic temporal trend of HFRS, and identified climate-related risk factors and their roles in HFRS transmission in Shenyang, China. Methods The annual and monthly cumulative numbers of HFRS cases from 2004 to 2009 were calculated and plotted to show the annual and seasonal fluctuation in Shenyang. Cross-correlation and autocorrelation analyses were performed to detect the lagged effect of climate factors on HFRS transmission and the autocorrelation of monthly HFRS cases. Principal component analysis was constructed by using climate data from 2004 to 2009 to extract principal components of climate factors to reduce co-linearity. The extracted principal components and autocorrelation terms of monthly HFRS cases were added into a multiple regression model called principal components regression model (PCR to quantify the relationship between climate factors, autocorrelation terms and transmission of HFRS. The PCR model was compared to a general multiple regression model conducted only with climate factors as independent variables. Results A distinctly declining temporal trend of annual HFRS incidence was identified. HFRS cases were reported every month, and the two peak periods occurred in spring (March to May and winter (November to January, during which, nearly 75% of the HFRS cases were reported. Three principal components were extracted with a cumulative contribution rate of 86.06%. Component 1 represented MinRH0, MT1, RH1, and MWV1; component 2 represented RH2, MaxT3, and MAP3; and component 3 represented MaxT2, MAP2, and MWV2. The PCR model

  11. The origin of Cenozoic magmatism of Libya

    Science.gov (United States)

    Stuart, Finlay; Masoud, Abdelmoniem; Mark, Darren

    2014-05-01

    Cenozoic volcanic provinces cover 66,000 km2 of Libya. The main fields are aligned NNW-SSE where NE-SW trending structural features intersect the main regional uplift structures. They form some of the largest volcanic provinces in North Africa yet despite their size and relative accessibility they have been not studied in detail. We are engaged in a new study of the geochemistry (major-trace elements, REE, Sr-Nd-Pb isotopes) and geochronology (40Ar/39Ar and cosmogenic 3He) of basalts of the four main Cenozoic volcanic provinces (Garian, Jabal Al Hasawinah, Jabal As Sawda and Jabal Al Haruj) in order to elucidate the nature and origin of the volcanism. The volcanic fields are dominated by basaltic flows, with small volumes of phonolites present at Garian and Jabal Al Hasawinah. Basalt piles rarely exceed a few 10s metres thick and the presence of NW-SE trending dykes on the periphery of most fields implies that existing flows probably represent the latest phase of a protracted volcanic history in each region. The basalts tend to be alkali to mildly alkali. Compositional variation is dominated by fractional crystalisation with little indication of crustal contamination. Trace element and REE support an origin in 5 to 15 % melts of heterogeneous sub-lithosphere mantle. Nd and Sr isotopic composition of the Garian and Jabal Al Haruj basalts (0.5128-0.51294 and 0.703-0.704) overlap the Cenozoic volcanism of southern Italy characterized by Etna and Pantelleria. This is typical of the common European asthenosphere mantle reservoir, and lacks the influence of enriched mantle present in other North African Cenozoic basalt provinces. There has been no systematic change in the location of volcanism with time that is indicative of plate movement over a fixed mantle hotspot. The major pulse of basaltic volcanism in the northern (Garian) and southern (Jabal Al Haruj) provinces overlap in time (6-1 Ma,) while Jabal Al Hasawinah and Jabal As Sawda basalts were erupted

  12. Uncertainty of climate change impacts and consequences on the prediction of future hydrological trends

    International Nuclear Information System (INIS)

    In the future, water is very likely to be the resource that will be most severely affected by climate change. It has been shown that small perturbations in precipitation frequency and/or quantity can result in significant impacts on the mean annual discharge. Moreover, modest changes in natural inflows result in larger changes in reservoir storage. There is however great uncertainty linked to changes in both the magnitude and direction of future hydrological trends. This presentation discusses the various sources of this uncertainty and their potential impact on the prediction of future hydrological trends. A companion paper will look at adaptation potential, taking into account some of the sources of uncertainty discussed in this presentation. Uncertainty is separated into two main components: climatic uncertainty and 'model and methods' uncertainty. Climatic uncertainty is linked to uncertainty in future greenhouse gas emission scenarios (GHGES) and to general circulation models (GCMs), whose representation of topography and climate processes is imperfect, in large part due to computational limitations. The uncertainty linked to natural variability (which may or may not increase) is also part of the climatic uncertainty. 'Model and methods' uncertainty regroups the uncertainty linked to the different approaches and models needed to transform climate data so that they can be used by hydrological models (such as downscaling methods) and the uncertainty of the models themselves and of their use in a changed climate. The impacts of the various sources of uncertainty on the hydrology of a watershed are demonstrated on the Peribonka River basin (Quebec, Canada). The results indicate that all sources of uncertainty can be important and outline the importance of taking these sources into account for any impact and adaptation studies. Recommendations are outlined for such studies. (author)

  13. Diverging climate trends in Mongolian taiga forests influence growth and regeneration of Larix sibirica

    OpenAIRE

    Dulamsuren, Choimaa; Hauck, Markus; Khishigjargal, Mookhor; Leuschner, Hanns; Leuschner, Christoph

    2010-01-01

    Central and semiarid north-eastern Asia was subject to twentieth century warming far above the global average. Since forests of this region occur at their drought limit, they are particularly vulnerable to climate change. We studied the regional variations of temperature and precipitation trends and their effects on tree growth and forest regeneration in Mongolia. Tree-ring series from more than 2,300 trees of Siberian larch (Larix sibirica) collected in four regions of Mongolia’s forest zone...

  14. Prediction Research of Climate Change Trends over North China in the Future 30 Years

    Institute of Scientific and Technical Information of China (English)

    LIU Yanxiang; YAN Jinghui; WU Tongwen; GUO Yufu; CHEN Lihua; WANG Jianping

    2008-01-01

    A simulation of climate change trends over North China in the past 50 years and future 30 years was performed with the actual greenhouse gas concentration and IPCC SRES B2 scenario concentration by IAP/LASG GOALS 4.0 (Global Ocean-Atmosphere-Land system coupled model), developed by the State Key Laboratory of Numerical Modelling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG),Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences (CAS). In order to validate the model,the modern climate during 1951-2000 was first simulated by the GOALS model with the actual greenhouse gas concentration, and the simulation results were compared with observed data. The simulation results basically reproduce the lower temperature from the 1960s to mid-1970s and the warming from the 1980sfor the globe and Northern Hemisphere, and better the important cold (1950-1976) and warm (1977-2000)periods in the past 50 years over North China. The correlation coefficient is 0.34 between simulations and observations (significant at a more than 0.05 confidence level). The range of winter temperature departures for North China is between those for the eastern and western China's Mainland. Meanwhile, the summer precipitation trend turning around the 1980s is also successfully simulated. The climate change trends in the future 30 years were simulated with the CO2 concentration under IPCC SRES-B2 emission scenario.The results show that, in the future 30 years, winter temperature will keep a warming trend in North China and increase by about 2.5℃ relative to climate mean (1960-1990). Meanwhile, summer precipitation will obviously increase in North China and decrease in South China, displaying a south-deficit-north-excessive pattern of precipitation.

  15. Seismic facies and stratigraphy of the Cenozoic succession in McMurdo Sound, Antarctica: Implications for tectonic, climatic and glacial history

    Science.gov (United States)

    Fielding, C.R.; Whittaker, J.; Henrys, S.A.; Wilson, T.J.; Nash, T.R.

    2007-01-01

    A new stratigraphic model is presented for the evolution of the Cenozoic Victoria Land Basin of the West Antarctic Rift, based on integration of seismic reflection and drilling data. The Early Rift phase (?latest Eocene to Early Oligocene) comprises wedges of strata confined by early extensional faults, and which contain seismic facies consistent with drainage via coarse-grained fans and deltas into discrete, actively subsiding grabens and half-grabens. The Main Rift phase (Early Oligocene to Early Miocene) comprises a lens of strata that thickens symmetrically from the basin margins into a central depocenter, and in which stratal events pass continuously over the top of the Early Rift extensional topography. Internal seismic facies and lithofacies indicate a more organized, cyclical shallow marine succession, influenced increasingly upward by cycles of glacial advance and retreat into the basin. The Passive Thermal Subsidence phase (Early Miocene to ?) comprises an evenly distributed sheet of strata that does not thicken appreciably into the depocentre, with more evidence for clinoform sets and large channels. These patterns are interpreted to record accumulation under similar environmental conditions but in a regime of slower subsidence. The Renewed Rifting phase (? to Recent, largely unsampled by coring thus far) has been further divided into 1, a lower interval, in which the section thickens passively towards a central depocentre, and 2. an upper interval, in which more dramatic thickening patterns are complicated by magmatic activity. The youngest part of the stratigraphy was accumulated under the influence of flexural loading imposed by the construction of large volcanic edifices, and involved minimal sediment supply from the western basin margin, suggesting a change in environmental (glacial) conditions at possibly c. 2 Ma.

  16. Potential evapotranspiration trend analysis for different climatic zones in Khyber Pakhtunkhwa, Pakistan

    International Nuclear Information System (INIS)

    Estimation of potential evapotranspiration (ETo) plays a significant role in the study of water resources management. The study was conducted to investigate the change in potential evapotranspiration value during the past three decade in three diverse climatic zones of Khyber Pakhtunkhwa, Pakistan. Three Districts of Khyber Pakhtunkhwa, Pakistan (Chitral, Peshawar and D. I. Khan) were selected based on their climatic diversity. Thirty years climatic data (1981-2010) obtained from Pakistan Metrological Department, Islamabad and Agriculture Research Institute, Peshawar was used. Potential evapotranspiration was determined for three decades separately, as well as on mean monthly basis. World Meteorological Organization (WMO) technique was used for trend analysis. Results revealed highest ETo in D. I. Khan followed by Peshawar and Chitral. However, in the summer months ETo value was found highest in Chitral as compared to other selected Districts. Trend analysis results showed that decrease in ETo trend was observed in all the selected Districts with the passage of time. It can be concluded that ETo values decreased as compared to past in all the selected Districts without any discrimination of physical geography and location. (author)

  17. Trends in combined climate indices in Serbia from 1961 to 2010

    Science.gov (United States)

    Arsenović, Pavle; Tošić, Ivana; Unkašević, Miroslava

    2015-08-01

    In this study, trends of combined climate indices based on daily mean temperatures and precipitation were analysed. The combined indices Cold/Dry (CD), Cold/Wet (CW), Warm/Dry (WD) and Warm/Wet (WW) days were examined during the period 1961-2010 at seven stations distributed across Serbia. Decreasing tendencies of CD and CW and increasing tendencies of WD were observed during the winter, spring and summer. It was found that trends of all combined indices were insignificant during the autumn. The most significant trends of CD and WD were revealed for the summer season. The results showed that a negative correlation existed between the East Atlantic pattern and CD and CW, but that a positive correlation existed for WD for all seasons. The North Atlantic Oscillation dominated during the winter, and the East Atlantic/West Russia pattern governed during the autumn.

  18. Precipitation Trend Analysis over Eastern Region of India Using Cmip5 Based Climatic Models

    Science.gov (United States)

    Kundu, A.; Dwivedi, S.; Chandra, V.

    2014-12-01

    Climate science is a complex field as climate is governed by processes that interact and operate on a vast array of time and space scales. The processes involving radiative transfer, chemistry and phase changes of water are most easily described at atomic and molecular scales; the influence of ice sheets, continents and planetary scale circulations controlling the basic energy balance of the planet operate at continental scales; even planetary orbital and solar variations operating at millennial time scales cannot be ignored. Global as well as regional climate has changed due to human activities like land use changes, production of industrial effluents and other activities due to the development of the society. The consequences of these changes have a massive impact on atmospheric events like precipitation, temperature etc. So, present and future information of precipitation is required to develop adaptation and mitigation strategies at national and international levels. Precipitation is one of the major phenomena of the atmosphere. So, its prediction and the trend are very necessary to realize the change of climate. The study attempted some model based analysis to assess prediction of rainfall trend using MK test and the Sen's slope estimator.

  19. Climatic modulation of recent trends in ocean acidification in the California Current System

    Science.gov (United States)

    Turi, G.; Lachkar, Z.; Gruber, N.; Münnich, M.

    2016-01-01

    We reconstruct the evolution of ocean acidification in the California Current System (CalCS) from 1979 through 2012 using hindcast simulations with an eddy-resolving ocean biogeochemical model forced with observation-based variations of wind and fluxes of heat and freshwater. We find that domain-wide pH and {{{Ω }}}{arag} in the top 60 m of the water column decreased significantly over these three decades by about -0.02 decade-1 and -0.12 decade-1, respectively. In the nearshore areas of northern California and Oregon, ocean acidification is reconstructed to have progressed much more rapidly, with rates up to 30% higher than the domain-wide trends. Furthermore, ocean acidification penetrated substantially into the thermocline, causing a significant domain-wide shoaling of the aragonite saturation depth of on average -33 m decade-1 and up to -50 m decade-1 in the nearshore area of northern California. This resulted in a coast-wide increase in nearly undersaturated waters and the appearance of waters with {{{Ω }}}{arag}\\lt 1, leading to a substantial reduction of habitat suitability. Averaged over the whole domain, the main driver of these trends is the oceanic uptake of anthropogenic CO2 from the atmosphere. However, recent changes in the climatic forcing have substantially modulated these trends regionally. This is particularly evident in the nearshore regions, where the total trends in pH are up to 50% larger and trends in {{{Ω }}}{arag} and in the aragonite saturation depth are even twice to three times larger than the purely atmospheric CO2-driven trends. This modulation in the nearshore regions is a result of the recent marked increase in alongshore wind stress, which brought elevated levels of dissolved inorganic carbon to the surface via upwelling. Our results demonstrate that changes in the climatic forcing need to be taken into consideration in future projections of the progression of ocean acidification in coastal upwelling regions.

  20. Streamflow Trends and Responses to Climate Variability and Land Cover Change in South Dakota

    Directory of Open Access Journals (Sweden)

    Karishma Niloy Kibria

    2016-01-01

    Full Text Available Trends in high, moderate, and low streamflow conditions from United States Geological Survey (USGS gauging stations were evaluated for a period of 1951–2013 for 18 selected watersheds in South Dakota (SD using a modified Mann-Kendall test. Rainfall trends from 21 rainfall observation stations located within 20-km of the streamflow gauging stations were also evaluated for the same study period. The concept of elasticity was used to examine sensitivity of streamflow to variation in rainfall and land cover (i.e., grassland in the study watersheds. Results indicated significant increasing trends in seven of the studied streams (of which five are in the east and two are located in the west, nine with slight increasing trends, and two with decreasing trends for annual streamflow. About half of the streams exhibited significant increasing trends in low and moderate flow conditions compared to high flow conditions. Ten rainfall stations showed slight increasing trends and seven showed decreasing trends for annual rainfall. Streamflow elasticity analysis revealed that streamflow was highly influenced by rainfall across the state (five of eastern streams and seven of western streams. Based on this analysis, a 10% increase in annual rainfall would result in 11%–30% increase in annual streamflow in more than 60% of SD streams. While streamflow appears to be more sensitive to rainfall across the state, high sensitivity of streamflow to rapid decrease in grassland area was detected in two western watersheds. This study provides valuable insight into of the relationship between streamflow, climate, and grassland cover in SD and would support further research and stakeholder decision making about water resources.

  1. Trends and Projections of Climatic Extremes in the Black Volta Basin, West Africa: Towards Climate Change Adaptation.

    Science.gov (United States)

    Aziz, F.

    2015-12-01

    The water resources of the Black Volta Basin in West Africa constitute a major resource for the four countries (Burkina Faso, Ghana, Côte d'Ivoire, Mali) that share it. For Burkina Faso and Ghana, the river is the main natural resource around which the development of the diverse sectors of the two economies is built. Whereas Ghana relies heavily on the river for energy, land-locked Burkina Faso continuously develops the water for agricultural purposes. Such important role of the river makes it an element around which there are potential conflicts: either among riparian countries or within the individual countries themselves. This study documents the changes in temperature and precipitation extremes in the Black Volta Basin region for the past (1981-2010) and makes projections for the mid-late 21st century (2051-2080) under two emission scenarios; RCP 2.6 and RCP 8.5. The Expert Team on Climate Change Detection and Indices (ETCCDI) temperature- and precipitation-based indices are computed with the RClimdex software. Observed daily records and downscaled CORDEX data of precipitation and maximum and minimum temperatures are used for historical and future trend analysis respectively. In general low emission scenarios show increases in the cold extremes. The region shows a consistent pattern of trends in hot extremes for the 1990's. An increasing trend in hot extremes is expected in the future under RCP 8.5 while RCP 2.5 shows reductions in hot extremes. Regardless of the emission scenario, projections show more frequent hot nights in the 21st century. Generally, the region shows variability in trends for future extreme precipitation indices with only a few of the trends being statistically significant (5% level). Results obtained provide a basic and first step to understanding how climatic extremes have been changing in the Volta Basin region and gives an idea of what to expect in the future. Such studies will also help in making informed decisions on water management

  2. New gridded daily climatology of Finland: Permutation-based uncertainty estimates and temporal trends in climate

    Science.gov (United States)

    Aalto, Juha; Pirinen, Pentti; Jylhä, Kirsti

    2016-04-01

    Long-term time series of key climate variables with a relevant spatiotemporal resolution are essential for environmental science. Moreover, such spatially continuous data, based on weather observations, are commonly used in, e.g., downscaling and bias correcting of climate model simulations. Here we conducted a comprehensive spatial interpolation scheme where seven climate variables (daily mean, maximum, and minimum surface air temperatures, daily precipitation sum, relative humidity, sea level air pressure, and snow depth) were interpolated over Finland at the spatial resolution of 10 × 10 km2. More precisely, (1) we produced daily gridded time series (FMI_ClimGrid) of the variables covering the period of 1961-2010, with a special focus on evaluation and permutation-based uncertainty estimates, and (2) we investigated temporal trends in the climate variables based on the gridded data. National climate station observations were supplemented by records from the surrounding countries, and kriging interpolation was applied to account for topography and water bodies. For daily precipitation sum and snow depth, a two-stage interpolation with a binary classifier was deployed for an accurate delineation of areas with no precipitation or snow. A robust cross-validation indicated a good agreement between the observed and interpolated values especially for the temperature variables and air pressure, although the effect of seasons was evident. Permutation-based analysis suggested increased uncertainty toward northern areas, thus identifying regions with suboptimal station density. Finally, several variables had a statistically significant trend indicating a clear but locally varying signal of climate change during the last five decades.

  3. The end of trend-estimation for extreme floods under climate change?

    Science.gov (United States)

    Schulz, Karsten; Bernhardt, Matthias

    2016-04-01

    An increased risk of flood events is one of the major threats under future climate change conditions. Therefore, many recent studies have investigated trends in flood extreme occurences using historic long-term river discharge data as well as simulations from combined global/regional climate and hydrological models. Severe floods are relatively rare events and the robust estimation of their probability of occurrence requires long time series of data (6). Following a method outlined by the IPCC research community, trends in extreme floods are calculated based on the difference of discharge values exceeding e.g. a 100-year level (Q100) between two 30-year windows, which represents prevailing conditions in a reference and a future time period, respectively. Following this approach, we analysed multiple, synthetically derived 2,000-year trend-free, yearly maximum runoff data generated using three different extreme value distributions (EDV). The parameters were estimated from long term runoff data of four large European watersheds (Danube, Elbe, Rhine, Thames). Both, Q100-values estimated from 30-year moving windows, as well as the subsequently derived trends showed enormous variations with time: for example, estimating the Extreme Value (Gumbel) - distribution for the Danube data, trends of Q100 in the synthetic time-series range from -4,480 to 4,028 m³/s per 100 years (Q100 =10,071m³/s, for reference). Similar results were found when applying other extreme value distributions (Weibull, and log-Normal) to all of the watersheds considered. This variability or "background noise" of estimating trends in flood extremes makes it almost impossible to significantly distinguish any real trend in observed as well as modelled data when such an approach is applied. These uncertainties, even though known in principle are hardly addressed and discussed by the climate change impact community. Any decision making and flood risk management, including the dimensioning of flood

  4. Climate reconstructions of the NH mean temperature: Can underestimation of trends and variability be avoided?

    Science.gov (United States)

    Christiansen, Bo

    2010-05-01

    Knowledge about the climate in the period before instrumental records are available is based on climate proxies obtained from tree-rings, sediments, ice-cores etc. Reconstructing the climate from such proxies is therefore necessary for studies of climate variability and for placing recent climate change into a longer term perspective. More than a decade ago pioneering attempts at using a multi-proxy dataset to reconstruct the Northern Hemisphere (NH) mean temperature resulted in the much published "hockey-stick"; a NH mean temperature that did not vary much before the rapid increase in the last century. Subsequent reconstructions show some differences but the overall "hockey-stick" structure seems to be a persistent feature However, there has been an increasing awareness of the fact that the applied reconstruction methods underestimate the low-frequency variability and trends. The recognition of the inadequacies of the reconstruction methods has to a large degree originated from pseudo-proxy studies, i.e., from long climate model experiments where artificial proxies have been generated and reconstructions based on these have been compared to the known model climate. It has also been found that reconstructions contain a large element of stochasticity which is revealed as broad distributions of skills. This means that it is very difficult to draw conclusions from a single or a few realizations. Climate reconstruction methods are based on variants of linear regression models relating temperatures and proxies. In this contribution we review some of the theory of linear regression and error-in-variables models to identify the sources of the underestimation of variability. Based on the gained insight we formulate a reconstruction method supposed to minimize this underestimation. The method is tested by applying it to an ensemble of surrogate temperature fields based on two climate simulations covering the last 500 and 1000 years. Compared to the RegEM TTLS method and a

  5. Prevailing climatic trends and runoff response from Hindukush–Karakoram–Himalaya, upper Indus basin

    Directory of Open Access Journals (Sweden)

    S. Hasson

    2015-03-01

    Full Text Available Largely depending on meltwater from the Hindukush–Karakoram–Himalaya, withdrawals from the upper Indus basin (UIB contribute to half of the surface water availability in Pakistan, indispensable for agricultural production systems, industrial and domestic use and hydropower generation. Despite such importance, a comprehensive assessment of prevailing state of relevant climatic variables determining the water availability is largely missing. Against this background, we present a comprehensive hydro-climatic trend analysis over the UIB, including for the first time observations from high-altitude automated weather stations. We analyze trends in maximum, minimum and mean temperatures (Tx, Tn, and Tavg, respectively, diurnal temperature range (DTR and precipitation from 18 stations (1250–4500 m a.s.l. for their overlapping period of record (1995–2012, and separately, from six stations of their long term record (1961–2012. We apply Mann–Kendall test on serially independent time series to assess existence of a trend while true slope is estimated using Sen's slope method. Further, we statistically assess the spatial scale (field significance of local climatic trends within ten identified sub-regions of UIB and analyze whether the spatially significant (field significant climatic trends qualitatively agree with a trend in discharge out of corresponding sub-region. Over the recent period (1995–2012, we find a well agreed and mostly field significant cooling (warming during monsoon season i.e. July–October (March–May and November, which is higher in magnitude relative to long term trends (1961–2012. We also find general cooling in Tx and a mixed response in Tavg during the winter season and a year round decrease in DTR, which are in direct contrast to their long term trends. The observed decrease in DTR is stronger and more significant at high altitude stations (above 2200 m a.s.l., and mostly due to higher cooling in Tx than in Tn

  6. APPLYING SEASONAL CLIMATE TRENDS TO AGRICULTURAL PRODUCTION IN TANJUNG KARANG, MALAYSIA

    Directory of Open Access Journals (Sweden)

    Mohd Ekhwan Toriman

    2014-01-01

    Full Text Available The North West Selangor Integrated Agriculture Development Agency (NWS-IADA is the most productive agricultural part in Selangor, Malaysia. This is partly because of the inherent high fertility of the soils and the moderate variable climate. However, with increasing global concern about climate impacts, this article examines relative importance of climate influences on the paddy production rate over 28 years (1980-2008. Data collection involved compiling and analyzing climate records from auxiliary station MARDI, Tg. Karang, Malaysia (Station no. 44325, 24 m M.S.L at the coordinates of N 03° 27’ 17” E 101° 09’ 24”. The results indicate that the average rainfall recorded is 1, 765 mm which is similar to national rainfall trend. Meanwhile, the daily humidity varied between 94-96% (8.00 AM and around 70% (2.00 PM while the sunshine hours ranged between 2.3 to 9.5 h. A correlation analysis between the production yield and climatic data at the studied area for the year 2000-2008, showed that for precipitation; rainfall is redundant during the main season while during the off season it bears direct effect on the production yield with the R2 value of -0.293 and 0.1715, respectively; Sunshine hours and temperature demonstrate their importance to production yield as suggested with their respective R2 values.

  7. The importance of external climate forcing for the variability and trends of coastal upwelling in past and future climate

    Science.gov (United States)

    Tim, Nele; Zorita, Eduardo; Hünicke, Birgit; Yi, Xing; Emeis, Kay-Christian

    2016-06-01

    The eastern boundary upwelling systems, located in the subtropics at the eastern boundary of the Atlantic and Pacific oceans and mainly driven by the trade winds, are the major coastal upwelling regions. Previous studies have suggested that the intensity of upwelling in these areas in the past centuries may have been influenced by the external radiative forcing, for instance by changes in solar irradiance, and it will also be influenced in the future by the increasing atmospheric greenhouse gases. Here, we analyse the impact of the external climate forcing on these upwelling systems in ensembles of simulations of two Earth system models. The ensembles contain three simulations for each period covering the past millennium (900-1849) and the 20th century (1850-2005). One of these Earth system models additionally includes the near future (2006-2100). Using a set of simulations, differing only in their initial conditions, enables us to test whether the observed variability and trends are driven by the external radiative forcing. Our analysis shows that the variability of the simulated upwelling is largely not affected by the external forcing and that, generally, there are no significant trends in the periods covering the past and future. Only in future simulations with the strongest increase of greenhouse gas concentrations the upwelling trends are significant and appear in all members of the ensemble.

  8. Recent Trends in the Ebro River Basin: Is It All "Just" Climate Change?

    Science.gov (United States)

    Lutz, Stefanie; Merz, Ralf

    2016-04-01

    Water resources are under pressure from a variety of stressors such as industry, agriculture, water abstraction or pollution. Changing climate can potentially enhance the impact of these stressors, especially under water scarcity conditions. The aim of the GLOBAQUA project ("Managing the effects of multiple stressors on aquatic ecosystems under water scarcity") is, therefore, to analyze the combined effect of multiple stressors in the context of increasing water scarcity. As part of the GLOBAQUA project, this study examines recent trends in climate, water quantity and quality parameters in the Ebro River Basin in Northern Spain to identify stressors and determine their joint impact on water resources. Mann-Kendall trend analyses of temperature, precipitation, streamflow, groundwater level, streamwater and groundwater quality data (spanning between 15 and 40 years) were performed. Moreover, anthropogenic pressures such as land use and alteration of natural flow by reservoirs were considered. Climate data indicate increasing temperatures in the Ebro River Basin especially in summer and autumn, and decreasing precipitation particularly in summer. In contrast, precipitation mostly shows upwards trends in autumn, but these are counterbalanced by greater evapotranspiration due to higher temperatures. Overall, this results in annual and seasonal streamflow decreases at the majority of gauging stations. Declining trends in streamflow are most pronounced during summer and are also observed in subbasins without reservoirs. Diminishing water resources become also apparent in generally decreasing groundwater levels in the Ebro River Basin. This decrease is most pronounced in areas where groundwater serves as main origin for irrigation water, which demonstrates how land use acts as a local rather than regional driver of change. Increasing air temperatures correlate with increasing water temperatures over the past 30 years, which indicates the effect of changing climate on water

  9. Trends in wintertime climate in the northeastern United States: 1965-2005

    Science.gov (United States)

    Burakowski, Elizabeth A.; Wake, Cameron P.; Braswell, Bobby; Brown, David P.

    2008-10-01

    Humans experience climate variability and climate change primarily through changes in weather at local and regional scales. One of the most effective means to track these changes is through detailed analysis of meteorological data. In this work, monthly and seasonal trends in recent winter climate of the northeastern United States (NE-US) are documented. Snow cover and snowfall are important components of the region's hydrological systems, ecosystems, infrastructure, travel safety, and winter tourism and recreation. Temperature, snowfall, and snow depth data were collected from the merged United States Historical Climate Network (USHCN) and National Climatic Data Center Cooperative Network (COOP) data set for the months of December through March, 1965-2005. Monthly and seasonal time series of snow-covered days (snow depth >2.54 cm) are constructed from daily snow depth data. Spatial coherence analysis is used to address data quality issues with daily snowfall and snow depth data, and to remove stations with nonclimatic influences from the regional analysis. Monthly and seasonal trends in mean, minimum, and maximum temperature, total snowfall, and snow-covered days are evaluated over the period 1965-2005, a period during which global temperature records and regional indicators exhibit a shift to warmer climate conditions. NE-US regional winter mean, minimum, and maximum temperatures are all increasing at a rate ranging from 0.42° to 0.46°C/decade with the greatest warming in all three variables occurring in the coldest months of winter (January and February). The regional average reduction in number of snow-covered days in winter (-8.9 d/decade) is also greatest during the months of January and February. Further analysis with additional regional climate modeling is required to better investigate the causal link between the increases in temperature and reduction in snow cover during the coldest winter months of January and February. In addition, regionally averaged

  10. Health in climate change research from 1990 to 2014: positive trend, but still underperforming

    Science.gov (United States)

    Verner, Glenn; Schütte, Stefanie; Knop, Juliane; Sankoh, Osman; Sauerborn, Rainer

    2016-01-01

    Background Climate change has been recognized as both one of the biggest threats and the biggest opportunities for global health in the 21st century. This trend review seeks to assess and characterize the amount and type of scientific literature on the link between climate change and human health. Design We tracked the use of climate-related terms and their co-occurrence with health terms during the 25 years since the first Intergovernmental Panel on Climate Change (IPCC) report, from 1990 to 2014, in two scientific databases and in the IPCC reports. We investigated the trends in the number of publications about health and climate change through time, by nature of the health impact under study, and by geographic area. We compared the scientific production in the health field with that of other sectors on which climate change has an impact. Results The number of publications was extremely low in both databases from 1990 (325 and 1,004, respectively) until around 2006 (1,332 and 4,319, respectively), which has since then increased exponentially in recent years (6,079 and 17,395, respectively, in 2014). However, the number of climate change papers regarding health is still about half that of other sectors. Certain health impacts, particularly malnutrition and non-communicable diseases (NCDs), remain substantially understudied. Approximately two-thirds of all published studies were carried out in OECD countries (Organization for Economic Cooperation and Development), predominantly in Europe and North America. Conclusions There is a clear need for further research on the links between climate change and health. This pertains particularly to research in and by those countries in which health will be mostly affected and capacity to adapt is least. Specific undertreated topics such as NCDs, malnutrition, and mental health should gain the priority they deserve. Funding agencies are invited to take note of and establish calls for proposals accordingly. Raising the interest

  11. Health in climate change research from 1990 to 2014: positive trend, but still underperforming

    Directory of Open Access Journals (Sweden)

    Glenn Verner

    2016-06-01

    Full Text Available Background: Climate change has been recognized as both one of the biggest threats and the biggest opportunities for global health in the 21st century. This trend review seeks to assess and characterize the amount and type of scientific literature on the link between climate change and human health. Design: We tracked the use of climate-related terms and their co-occurrence with health terms during the 25 years since the first Intergovernmental Panel on Climate Change (IPCC report, from 1990 to 2014, in two scientific databases and in the IPCC reports. We investigated the trends in the number of publications about health and climate change through time, by nature of the health impact under study, and by geographic area. We compared the scientific production in the health field with that of other sectors on which climate change has an impact. Results: The number of publications was extremely low in both databases from 1990 (325 and 1,004, respectively until around 2006 (1,332 and 4,319, respectively, which has since then increased exponentially in recent years (6,079 and 17,395, respectively, in 2014. However, the number of climate change papers regarding health is still about half that of other sectors. Certain health impacts, particularly malnutrition and non-communicable diseases (NCDs, remain substantially understudied. Approximately two-thirds of all published studies were carried out in OECD countries (Organization for Economic Cooperation and Development, predominantly in Europe and North America. Conclusions: There is a clear need for further research on the links between climate change and health. This pertains particularly to research in and by those countries in which health will be mostly affected and capacity to adapt is least. Specific undertreated topics such as NCDs, malnutrition, and mental health should gain the priority they deserve. Funding agencies are invited to take note of and establish calls for proposals accordingly

  12. Sphagnum peatland development at their southern climatic range in West Siberia: trends and peat accumulation patterns

    Energy Technology Data Exchange (ETDEWEB)

    Peregon, Anna [Center for Global Environmental Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan); Uchida, Masao [Environmental Chemistry Division, NIES-TERRA AMS Facility, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan); Shibata, Yasuyuki [Environmental Chemistry Division, NIES-TERRA AMS Facility, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan)

    2007-10-15

    A region of western Siberia is vulnerable to the predicted climatic change which may induce an important modification to the carbon balance in wetland ecosystems. This study focuses on the evaluation of both the long-term and contemporary trends of peat (carbon) accumulation and its patterns at the southern climatic range of Sphagnum peatlands in western Siberia. Visible and physical features of peat and detailed reconstructions of successional change (or sediment stratigraphies) were analysed at two types of forest-peatland ecotones, which are situated close to each other but differ by topography and composition of their plant communities. Our results suggest that Siberian peatlands exhibit a general trend towards being a carbon sink rather than a source even at or near the southern limit of their distribution. Furthermore, two types of peat accumulation were detected in the study area, namely persistent and intermittent. As opposed to persistent peat accumulation, the intermittent one is characterized by the recurrent degradation of the upper peat layers at the marginal parts of raised bogs. Persistent peat accumulation is the case for the majority of Sphagnum peatlands under current climatic conditions. It might be assumed that more peat will accumulate under the 'increased precipitation' scenarios of global warming, although intermittent peat accumulation could result in the eventual drying that may change peatlands from carbon sinks to carbon sources.

  13. Predicting ecological changes on benthic estuarine assemblages through decadal climate trends along Brazilian Marine Ecoregions

    Science.gov (United States)

    Bernardino, Angelo F.; Netto, Sérgio A.; Pagliosa, Paulo R.; Barros, Francisco; Christofoletti, Ronaldo A.; Rosa Filho, José S.; Colling, André; Lana, Paulo C.

    2015-12-01

    Estuaries are threatened coastal ecosystems that support relevant ecological functions worldwide. The predicted global climate changes demand actions to understand, anticipate and avoid further damage to estuarine habitats. In this study we reviewed data on polychaete assemblages, as a surrogate for overall benthic communities, from 51 estuaries along five Marine Ecoregions of Brazil (Amazonia, NE Brazil, E Brazil, SE Brazil and Rio Grande). We critically evaluated the adaptive capacity and ultimately the resilience to decadal changes in temperature and rainfall of the polychaete assemblages. As a support for theoretical predictions on changes linked to global warming we compared the variability of benthic assemblages across the ecoregions with a 40-year time series of temperature and rainfall data. We found a significant upward trend in temperature during the last four decades at all marine ecoregions of Brazil, while rainfall increase was restricted to the SE Brazil ecoregion. Benthic assemblages and climate trends varied significantly among and within ecoregions. The high variability in climate patterns in estuaries within the same ecoregion may lead to correspondingly high levels of noise on the expected responses of benthic fauna. Nonetheless, we expect changes in community structure and productivity of benthic species at marine ecoregions under increasing influence of higher temperatures, extreme events and pollution.

  14. Sphagnum peatland development at their southern climatic range in West Siberia: trends and peat accumulation patterns

    International Nuclear Information System (INIS)

    A region of western Siberia is vulnerable to the predicted climatic change which may induce an important modification to the carbon balance in wetland ecosystems. This study focuses on the evaluation of both the long-term and contemporary trends of peat (carbon) accumulation and its patterns at the southern climatic range of Sphagnum peatlands in western Siberia. Visible and physical features of peat and detailed reconstructions of successional change (or sediment stratigraphies) were analysed at two types of forest-peatland ecotones, which are situated close to each other but differ by topography and composition of their plant communities. Our results suggest that Siberian peatlands exhibit a general trend towards being a carbon sink rather than a source even at or near the southern limit of their distribution. Furthermore, two types of peat accumulation were detected in the study area, namely persistent and intermittent. As opposed to persistent peat accumulation, the intermittent one is characterized by the recurrent degradation of the upper peat layers at the marginal parts of raised bogs. Persistent peat accumulation is the case for the majority of Sphagnum peatlands under current climatic conditions. It might be assumed that more peat will accumulate under the 'increased precipitation' scenarios of global warming, although intermittent peat accumulation could result in the eventual drying that may change peatlands from carbon sinks to carbon sources

  15. Climate and hydrological changes in the northeastern United States : recent trends and implications for forested and aquatic ecosystems

    International Nuclear Information System (INIS)

    This study reviewed previous and projected changes in climatic and hydrologic conditions in the northeastern United States. While climatic warming and increases in precipitation, snow, and hydrologic regimes have been observed over the last 100 years, the most pronounced changes have occurred since 1970. However, trends in climatic and hydrological variables have differed both spatially and temporally in different regions. Decadal-scale climatic variations have also altered long-term trends. Climate models predict continued increases in both temperature and precipitation over the next century. Increases in growing season length are expected to increase evapotranspiration and the frequency of droughts. An increase in the frequency of droughts is also expected to increase the risk of fires and other disturbances. Forest productivity and maple syrup production will be impacted, and the intensity of autumn foliage coloration will be diminished. It was concluded that climate and hydrological changes will have a profound impact on forest structure, composition and ecological functioning. 131 refs., 5 figs

  16. The energy-climate challenge: Recent trends in CO2 emissions from fuel combustion

    International Nuclear Information System (INIS)

    Fossil fuel combustion is the single largest human influence on climate, accounting for 80% of anthropogenic greenhouse gas emissions. This paper presents trends in world carbon dioxide (CO2) emissions from fossil fuel combustion worldwide, based on the estimates of the International Energy Agency (IEA) [IEA, 2006a. CO2 Emissions from Fuel Combustion 1971-2004. International Energy Agency, Paris, France]. Analyzing the drivers of CO2 emissions, the paper considers regions, types of fuel, sectors, and socio-economic indicators. The paper then examines the growing body of climate change mitigation policies and measures, both multinational and federal. Policies discussed include the Kyoto Protocol, the European Union Emissions Trading Scheme, and the potential measures to be implemented in 2012 and beyond. CO2 emissions of recent years have grown at the highest rates ever recorded, an observed trend incompatible with stabilizing atmospheric concentrations of greenhouse gases and avoiding long-term climate change. Within this aggregate upward trend, a comparison of emissions sources proves dynamic: while industrialized countries have so far dominated historical emissions, rapid growth in energy demand of developing economies, led by China, may soon spur their absolute emissions beyond those of industrialized countries. To provide context for the drivers of CO2 emissions, the paper examines fuel sources, from coal to biofuels, and fuel use in the production of heat and electricity, in transport, in industrial production and in households. The sectoral analysis illustrates the primacy, in terms of emissions growth and absolute emissions, of two sectors: electricity and heat generation, and transport. A discussion of several socio-economic emissions drivers complements the paper's analysis of mitigation mechanisms. As illustrated, emissions per capita and emissions per unit of economic production, as measured in gross domestic product (GDP), vary widely between regions

  17. Interdisciplinary Research on Climate Change: Past Trends and Challenges for the Future

    Science.gov (United States)

    Marlon, J. R.; Mitchell, R.

    2009-12-01

    Interdisciplinary research is crucial to understanding complex and urgent environmental problems, particularly climate change. Universities are increasingly hosting trans-, multi-, and inter-disciplinary workshops and conferences and developing innovative interdisciplinary training programs (e.g., NSF’s IGERT program) to foster such research. Yet, much doctoral training remains highly disciplinary with very little evidence of graduate training producing transformative research that bridges the natural/social-science divide. Indeed, strong cultural and institutional obstacles often deter or preclude doctoral students from conducting such research. Here we analyze the past three decades of climate-change related dissertation abstracts to assess the balance between disciplinary and interdisciplinary scholarship among young climate change scholars. We analyze trends in the number of dissertations in natural vs. social science disciplines and code the abstracts of over 500 recent dissertations to assess how many dissertations reference one or more disciplines beyond the PhD-granting one. This research is sponsored by the Dissertations Initiative for the Advancement of Climate Change Research (DISCCRS).

  18. Cenozoic Climate-Tectonic Interactions in the Western Himalaya Recorded in the Indus Submarine Fan: Initial Results from IODP Expedition 355

    Science.gov (United States)

    Clift, Peter; Pandey, Dhananjai; Kulhanek, Denise; Andò, Sergio; Zhou, Peng; 355 Scientists Expedition

    2016-04-01

    The Indus Submarine Fan is the largest repository of clastic sediment eroded from the Western Himalayas since the start of India-Eurasia collision, likely around 50 Ma. Interpreting this sedimentary archive is central to understanding how the Asian monsoon and Himalaya have evolved together. Models indicate linkages between surface processes, controlled by climatic influences, and the tectonics of the solid Earth. The development of large-scale duplexes within the Lesser Himalaya starting in the Late Miocene may be linked to changes in erosion intensity and location, especially spanning the 7-8 Ma climatic transition previously identified in the foreland basin and offshore Oman. Although some of these issues can be addressed by studies onshore, erosion has removed much of the older record from the crystalline basement itself and the Siwalik Group foreland sediment tend to image limited stretches of the Himalayan front rather than supplying a basin-wide record. The sediment record of the Arabian Sea must be used to understand how the Indus catchment responds to changes in monsoon strength. Drilling by International Ocean Discovery Program Expedition 355 in the Eastern Arabian Sea has recovered two submarine fan sections spanning the last ca. 11 Ma, predated by a mass transport deposit. These should allow us to reconstruct how the Western Himalaya have responded to climate change since the late Miocene. Autocyclic processes within the fan and a major mass transport deposit mean that the record is not continuous, but is largely complete. Initial results indicate that the Indus Submarine Fan was receiving materials from Himalayan high-grade metamorphic rocks since at least ca. 14-17 Ma and that there was a direct connection with the suture, likely close to the western syntaxis, dating from the late Miocene. However, initial postcruise results now indicate that there has been significant flux directly from the Indian Peninsular, especially since 3 Ma that disrupts the

  19. Alaska tundra vegetation trends and their links to the large-scale climate

    Science.gov (United States)

    Bieniek, P. A.; Bhatt, U. S.; Walker, D. A.; Raynolds, M. K.; Comiso, J. C.

    2011-12-01

    The arctic Normalized Vegetation Index (NDVI) data set (a measure of vegetation photosynthetic capacity) has been used to document coherent temporal relationships between near-coastal sea ice, summer tundra land surface temperatures, and vegetation productivity throughout the Arctic (Bhatt et al. 2010). Land warming over North America has displayed larger trends (+30%) when compared to Eurasia (+16%) since 1982. In the tundra of northern Alaska the greatest change was found in absolute maximum NDVI along the Beaufort Sea coast (+14%). In contrast, tundra areas in southwest Alaska along the Bering Sea have seen a decline (-4%). Greenup date in these regions has been occurring as much as 1-4 days earlier per decade, but trends are mixed. Winter snow water equivalent (SWE) has only increased slightly (+0.1 mm/yr) in the Arctic region of Alaska since 1987 (R. Muskett, personal communication). These findings suggest that there have been changes in the seasonal climate in Alaska during the NDVI record. The tundra trends are further investigated by evaluating remotely sensed sea ice, surface air temperature, SWE, daily snow cover, and NDVI3g. While the snow data has a relatively short record (1999-2010), notable trends can be observed in snow melt, occurring as much 15 days earlier per decade in northern Alaska. Unfortunately, other snow data sets have been found to be problematic and could not be used to extend our analysis. This highlights the need for a long-term pan-arctic snow data set that is suitable for climate analysis. Possible climate drivers are also investigated. Results show that the summer tundra, in terms of NDVI and summer warmth index (SWI), has few direct links with the large-scale climate. However, the sea ice concentration along the coast of the tundra regions has strong preseason links to the large-scale climate. This suggests that the large-scale climate influences the sea ice concentration which then affects the NDVI and SWI. Three tundra regions

  20. Population Trends of Central European Montane Birds Provide Evidence for Adverse Impacts of Climate Change on High-Altitude Species.

    Directory of Open Access Journals (Sweden)

    Jiří Flousek

    Full Text Available Climate change is among the most important global threats to biodiversity and mountain areas are supposed to be under especially high pressure. Although recent modelling studies suggest considerable future range contractions of montane species accompanied with increased extinction risk, data allowing to test actual population consequences of the observed climate changes and identifying traits associated to their adverse impacts are very scarce. To fill this knowledge gap, we estimated long-term population trends of montane birds from 1984 to 2011 in a central European mountain range, the Giant Mountains (Krkonoše, where significant warming occurred over this period. We then related the population trends to several species' traits related to the climate change effects. We found that the species breeding in various habitats at higher altitudes had more negative trends than species breeding at lower altitudes. We also found that the species moved upwards as a response to warming climate, and these altitudinal range shifts were associated with more positive population trends at lower altitudes than at higher altitudes. Moreover, long-distance migrants declined more than residents or species migrating for shorter distances. Taken together, these results indicate that the climate change, besides other possible environmental changes, already influences populations of montane birds with particularly adverse impacts on high-altitude species such as water pipit (Anthus spinoletta. It is evident that the alpine species, predicted to undergo serious climatically induced range contractions due to warming climate in the future, already started moving along this trajectory.

  1. Decadal stream water quality trends under varying climate, land use, and hydrogeochemical setting in, Iowa, USA

    Science.gov (United States)

    Green, Christopher; Bekins, Barbara; Kalkhoff, Stephen; Hirsch, Robert; Liao, Lixia; Barnes, Kimberlee

    2015-04-01

    Understanding how nitrogen fluxes respond to changes in agricultural practices and climatic variations is important for improving water quality in agricultural settings. In the central United States, intensification of corn cropping in support of ethanol production led to increases in N application rates in the 2000s during a period including both extreme dry and wet conditions. To examine the effect of these recent changes, a study was conducted on surface water quality in 10 major Iowa Rivers. Long term (~20 to 30 years) water quality and flow data were analyzed with Weighted Regression on Time, Discharge and Season (WRTDS), a statistical method that provides internally consistent estimates of the concentration history and reveals decadal trends that are independent of random variations of stream flow from seasonal averages. Trends of surface water quality showed constant or decreasing flow-normalized concentrations of nitrate+nitrite-N from 2000 to 2012 in all basins. To evaluate effects of annual discharge and N loading on these trends, multiple conceptual models were developed and calibrated to annual concentrations. The recent declining concentration trends can be attributed to both very high and very low streamflow discharge in the 2000's and to the long (e.g. 8-year) subsurface residence times in some basins. Dilution of surface water nitrate and depletion of stored nitrate may occur in years with very high discharge. Limited transport of N to streams and accumulation of stored N may occur in years with very low discharge. Central Iowa basins showed the greatest reduction in concentrations, likely because extensive tile-drains limit the effective volumes for storage of N and reduce residence times, and because the glacial sediments in these basins promote denitrification. Changes in nitrogen fluxes resulting from ethanol production and other factors will likely be delayed for years or decades in peripheral basins of Iowa, and may be obscured in the central

  2. Historic Trends in U. S. Drought Forcing in a Warming Climate

    CERN Document Server

    Muschinski, T

    2014-01-01

    The mean North American and world climates have warmed significantly since the beginning of climatologically significant anthropogenic emission of greenhouse gases in the 19th Century. It has been suggested that warming may increase the frequency or severity of droughts. We define and study the statistics of an aridity index that describes the precipitation forcing function of a drought, considering drought to be a season with low enough precipitation to be significant for agriculture. Our aridity index is a reciprocal function of the seasonal precipitation, which is more significant for agriculture than mean precipitation. Using NOAA data from sites in 13 diverse climate regimes in the 48 contiguous United States with time series running over the period 1940--1999 but including two data series from 1900 or 1910, and computing their decadal averages, we search for linear trends in their aridity indices. We find no linear trends significant at the $2\\sigma$ level. At five sites $3\\sigma$ upper bounds on any sy...

  3. Coupled Aerosol-Chemistry-Climate Twentieth-Century Transient Model Investigation: Trends in Short-Lived Species and Climate Responses

    Science.gov (United States)

    Koch, Dorothy; Bauer, Susanne E.; Del Genio, Anthony; Faluvegi, Greg; McConnell, Joseph R.; Menon, Surabi; Miller, Ronald L.; Rind, David; Ruedy, Reto; Schmidt, Gavin A.; Shindell, Drew

    2011-01-01

    The authors simulate transient twentieth-century climate in the Goddard Institute for Space Studies (GISS) GCM, with aerosol and ozone chemistry fully coupled to one another and to climate including a full dynamic ocean. Aerosols include sulfate, black carbon (BC), organic carbon, nitrate, sea salt, and dust. Direct and BC snow-albedo radiative effects are included. Model BC and sulfur trends agree fairly well with records from Greenland and European ice cores and with sulfur deposition in North America; however, the model underestimates the sulfur decline at the end of the century in Greenland. Global BC effects peak early in the century (1940s); afterward the BC effects decrease at high latitudes of the Northern Hemisphere but continue to increase at lower latitudes. The largest increase in aerosol optical depth occurs in the middle of the century (1940s-80s) when sulfate forcing peaks and causes global dimming. After this, aerosols decrease in eastern North America and northern Eurasia leading to regional positive forcing changes and brightening. These surface forcing changes have the correct trend but are too weak. Over the century, the net aerosol direct effect is -0.41 Watts per square meter, the BC-albedo effect is -0.02 Watts per square meter, and the net ozone forcing is +0.24 Watts per square meter. The model polar stratospheric ozone depletion develops, beginning in the 1970s. Concurrently, the sea salt load and negative radiative flux increase over the oceans around Antarctica. Net warming over the century is modeled fairly well; however, the model fails to capture the dynamics of the observedmidcentury cooling followed by the late century warming.Over the century, 20% of Arctic warming and snow ice cover loss is attributed to the BC albedo effect. However, the decrease in this effect at the end of the century contributes to Arctic cooling. To test the climate responses to sulfate and BC pollution, two experiments were branched from 1970 that removed

  4. Long-term trend of climate variables in the upper Dong Nai river basin in Vietnam

    Science.gov (United States)

    Truong, Nguyen Cung Que; Nguyen, Hong Quan; Kondoh, Akihiko

    2015-04-01

    Dong Nai river and Mekong delta downstream are located in and supplied the major water resources to the whole Southern of Vietnam. In the state of continuous changes in water resources due to climate changes, there are several controversy about the potential impact of sediment transport and river flows downstream due to either the cascade hydroelectric power plant system or dam construction in the upper of Mekong delta. Therefore, management and planning for efficient use of Dong Nai river water resource is very important. Furthermore, that it is necessary to consider the hydrological regime change by the effects of climate variable. On the other hand, solving the problems of water shortage in the dry season and flood control in rainy season are also important for issues of water management at Dong Nai river basin. In this study we evaluated changes in two main factors of the water balance equation (both rainfall and evapotranspiration) to assess long-term change in the hydrological regime in the upper area of Dong Nai river basin. This key theme was divided into the following two sub-goals. The first goal was to analyze long term spatial and temporal rainfall trends. The second goal was to analyze the long-term trend of meteorological factors determining evapotranspiration such as air temperature, wind speed, solar radiation and sunshine duration. The results were used to assess their impact to evapotranspiration. The meteorological and hydrological data of the basin for the last 20 years (from 1993 to 2012) were analyzed based on the Empirical Mode Decomposition (EMD) method. The EMD method has been pioneered by Huang et al. (1998) for adaptively representing nonstationary time-series data as sum of zero-mean amplitude modulation-frequency modulation (AM-FM) components by iteratively conducting the sifting process. These components called Intrinsic Mode Functions (IMFs) allow the calculation of a meaningful multi-component instantaneous frequency. The results

  5. Climate trends and behaviour of drought indices based on precipitation and evapotranspiration in Portugal

    Directory of Open Access Journals (Sweden)

    A. A. Paulo

    2012-05-01

    Full Text Available Distinction between drought and aridity is crucial to understand water scarcity processes. Drought indices are used for drought identification and drought severity characterisation. The Standardised Precipitation Index (SPI and the Palmer Drought Severity Index (PDSI are the most known drought indices. In this study, they are compared with the modified PDSI for Mediterranean conditions (MedPDSI and the Standardised Precipitation Evapotranspiration Index (SPEI. MedPDSI results from the soil water balance of an olive crop, thus real evapotranspiration is considered, while SPEI uses potential (climatic evapotranspiration. Similarly to the SPI, SPEI can be computed at various time scales. Aiming at understanding possible impacts of climate change, prior to compare the drought indices, a trend analysis relative to precipitation and temperature in 27 weather stations of Portugal was performed for the period 1941 to 2006. A trend for temperature increase was observed for some weather stations and trends for decreasing precipitation in March and increasing in October were also observed for some locations. Comparisons of the SPI and SPEI at 9- and 12-month time scales, the PDSI and MedPDSI were performed for the same stations and period. SPI and SPEI produce similar results for the same time scales concerning drought occurrence and severity. PDSI and MedPDSI correlate well between them and the same happened for SPI and SPEI. PDSI and MedPDSI identify more severe droughts than SPI or SPEI and identify drought occurrence earlier than these indices. This behaviour is likely to be related with the fact that a water balance is performed with PDSI and MedPDSI, which better approaches the supply-demand balance.

  6. Recent climate trends and implications for water resources in the Catskill Mountain region, New York, USA

    Science.gov (United States)

    Burns, Douglas A.; Klaus, Julian; McHale, Michael R.

    2007-03-01

    SummaryClimate scientists have concluded that the earth's surface air temperature warmed by 0.6 °C during the 20th century, and that warming induced by increasing concentrations of greenhouse gases is likely to continue in the 21st century, accompanied by changes in the hydrologic cycle. Climate change has important implications in the Catskill region of southeastern New York State, because the region is a source of water supply for New York City. We used the non-parametric Mann-Kendall test to evaluate annual, monthly, and multi-month trends in air temperature, precipitation amount, stream runoff, and potential evapotranspiration (PET) in the region during 1952-2005 based on data from 9 temperature sites, 12 precipitation sites, and 8 stream gages. A general pattern of warming temperatures and increased precipitation, runoff, and PET is evident in the region. Regional annual mean air temperature increased significantly by 0.6 °C per 50 years during the period; the greatest increases and largest number of significant upward trends were in daily minimum air temperature. Daily maximum air temperature showed the greatest increase during February through April, whereas minimum air temperature showed the greatest increase during May through September. Regional mean precipitation increased significantly by 136 mm per 50 years, nearly double that of the regional mean increase in runoff, which was not significant. Regional mean PET increased significantly by 19 mm per 50 years, about one-seventh that of the increase in precipitation amount, and broadly consistent with increased runoff during 1952-2005, despite the lack of significance in the mean regional runoff trend. Peak snowmelt as approximated by the winter-spring center of volume of stream runoff generally shifted from early April at the beginning of the record to late March at the end of the record, consistent with a decreasing trend in April runoff and an increasing trend in maximum March air temperature. This

  7. Long Term Population, City Size and Climate Trends in the Fertile Crescent: A First Approximation.

    Science.gov (United States)

    Lawrence, Dan; Philip, Graham; Hunt, Hannah; Snape-Kennedy, Lisa; Wilkinson, T J

    2016-01-01

    Over the last 8000 years the Fertile Crescent of the Near East has seen the emergence of urban agglomerations, small scale polities and large territorial empires, all of which had profound effects on settlement patterns. Computational approaches, including the use of remote sensing data, allow us to analyse these changes at unprecedented geographical and temporal scales. Here we employ these techniques to examine and compare long term trends in urbanisation, population and climate records. Maximum city size is used as a proxy for the intensity of urbanisation, whilst population trends are modelled from settlement densities in nine archaeological surveys conducted over the last 30 years across the region. These two measures are then compared with atmospheric moisture levels derived from multiple proxy analyses from two locations close to the study area, Soreq Cave in Israel and Lake Van in south-eastern Turkey, as well as wider literature. The earliest urban sites emerged during a period of relatively high atmospheric moisture levels and conform to a series of size thresholds. However, after the Early Bronze Age maximum urban size and population levels increase rapidly whilst atmospheric moisture declines. We argue that although the initial phase of urbanization may have been linked to climate conditions, we can see a definitive decoupling of climate and settlement patterns after 2000 BC. We relate this phenomenon to changes in socio-economic organisation and integration in large territorial empires. The complex relationships sustaining urban growth during this later period resulted in an increase in system fragility and ultimately impacted on the sustainability of cities in the long term. PMID:27018998

  8. Long Term Population, City Size and Climate Trends in the Fertile Crescent: A First Approximation.

    Directory of Open Access Journals (Sweden)

    Dan Lawrence

    Full Text Available Over the last 8000 years the Fertile Crescent of the Near East has seen the emergence of urban agglomerations, small scale polities and large territorial empires, all of which had profound effects on settlement patterns. Computational approaches, including the use of remote sensing data, allow us to analyse these changes at unprecedented geographical and temporal scales. Here we employ these techniques to examine and compare long term trends in urbanisation, population and climate records. Maximum city size is used as a proxy for the intensity of urbanisation, whilst population trends are modelled from settlement densities in nine archaeological surveys conducted over the last 30 years across the region. These two measures are then compared with atmospheric moisture levels derived from multiple proxy analyses from two locations close to the study area, Soreq Cave in Israel and Lake Van in south-eastern Turkey, as well as wider literature. The earliest urban sites emerged during a period of relatively high atmospheric moisture levels and conform to a series of size thresholds. However, after the Early Bronze Age maximum urban size and population levels increase rapidly whilst atmospheric moisture declines. We argue that although the initial phase of urbanization may have been linked to climate conditions, we can see a definitive decoupling of climate and settlement patterns after 2000 BC. We relate this phenomenon to changes in socio-economic organisation and integration in large territorial empires. The complex relationships sustaining urban growth during this later period resulted in an increase in system fragility and ultimately impacted on the sustainability of cities in the long term.

  9. Long Term Population, City Size and Climate Trends in the Fertile Crescent: A First Approximation

    Science.gov (United States)

    Lawrence, Dan; Philip, Graham; Hunt, Hannah; Snape-Kennedy, Lisa; Wilkinson, T. J.

    2016-01-01

    Over the last 8000 years the Fertile Crescent of the Near East has seen the emergence of urban agglomerations, small scale polities and large territorial empires, all of which had profound effects on settlement patterns. Computational approaches, including the use of remote sensing data, allow us to analyse these changes at unprecedented geographical and temporal scales. Here we employ these techniques to examine and compare long term trends in urbanisation, population and climate records. Maximum city size is used as a proxy for the intensity of urbanisation, whilst population trends are modelled from settlement densities in nine archaeological surveys conducted over the last 30 years across the region. These two measures are then compared with atmospheric moisture levels derived from multiple proxy analyses from two locations close to the study area, Soreq Cave in Israel and Lake Van in south-eastern Turkey, as well as wider literature. The earliest urban sites emerged during a period of relatively high atmospheric moisture levels and conform to a series of size thresholds. However, after the Early Bronze Age maximum urban size and population levels increase rapidly whilst atmospheric moisture declines. We argue that although the initial phase of urbanization may have been linked to climate conditions, we can see a definitive decoupling of climate and settlement patterns after 2000 BC. We relate this phenomenon to changes in socio-economic organisation and integration in large territorial empires. The complex relationships sustaining urban growth during this later period resulted in an increase in system fragility and ultimately impacted on the sustainability of cities in the long term. PMID:27018998

  10. Identification of dominant climate factor for pan evaporation trend in the Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    LIU Xiaomang; ZHENG Hongxing; ZHANG Minghua; LIU Changming

    2011-01-01

    Despite the observed increase in global temperature,observed pan evaporation in many regions has been decreasing over the past 50 years,which is known as the “pan evaporation paradox”.The “pan evaporation paradox” also exists in the Tibetan Plateau,where pan evaporation has decreased by 3.06 mm a-2 (millimeter per annum).It is necessary to explain the mechanisms behind the observed decline in pan evaporation because the Tibetan Plateau strongly influences climatic and environmental changes in China,Asia and even in the Northern Hemisphere.In this paper,a derivation based approach has been used to quantitatively assess the contribution rate of climate factors to the observed pan evaporation trend across the Tibetan Plateau.The results showed that,provided the other factors remain constant,the increasing temperature should have led to a 2.73 mm a-2 increase in pan evaporation annually,while change in wind speed,vapor pressure and solar radiation should have led to a decrease in pan evaporation by 2.81 mm a-2,1.96 mm a-2 and 1.11 mm a-2 respectively from 1970 to 2005.The combined effects of the four climate variables have resuited in a 3.15 mm a-2 decrease in pan evaporation,which is close to the observed pan evaporation trend with a relative error of 2.94%.A decrease in wind speed was the dominant factor for the decreasing pan evaporation,followed by an increasing vapor pressure and decreasing solar radiation,all of which offset the effect of increasing temperature across the Tibetan Plateau.

  11. Grassland communities in the USA and expected trends associated with climate change

    Directory of Open Access Journals (Sweden)

    David Paul Belesky

    2016-06-01

    Full Text Available Grasslands, including managed grazinglands, represent one of the largest ecosystems on the planet. Managed grazinglands in particular tend to occupy marginal climatic and edaphic resource zones, thus exacerbating responses in net primary productivity relative to changes in system resources, including anthropogenic factors. Climate dynamism, as evident from the fossil record, appears to be a putative feature of our planet. Recent global trends in temperature and precipitation patterns seem to differ from long-term patterns and have been associated with human activities linked with increased greenhouse gas emissions; specifically CO2. Thus grasslands, with their diverse floristic components, and interaction with and dependence upon herbivores, have a remarkable ability to persist and sustain productivity in response to changing resource conditions. This resistance and resilience to change, including uncertain long-term weather conditions, establishes managed grasslands as an important means of protecting food security. We review responses of grassland communities across regions of the USA and consider the responses in productivity and system function with respect to climatic variation. Research is needed to identify plant resources and management technologies that strengthen our ability to capitalize upon physiological and anatomical features prevalent in grassland communities associated with varying growing conditions.

  12. Trends in seasonal precipitation extremes - An indicator of ‘climate change’ in Kerala, India

    Science.gov (United States)

    Pal, Indrani; Al-Tabbaa, Abir

    2009-03-01

    SummaryRecent news on the occurrence of off-seasonal natural disasters, such as pre-monsoon drought and post-monsoon flooding in India and particularly in the peninsular region, highlight the urgent need to look at the patterns of change in seasonal extremes at the local level. Kerala, the south-western state of the Indian peninsula, comprising of a total of six gridded areas, was chosen for this study focusing on the variability and changes in rainfall extremes in the different seasons. Since other studies by the authors have focused on the monsoon season, this paper considers the winter, spring and autumn seasons only. A set of indices derived from the daily rainfall time series is defined and used to examine the changes in extreme rainfall through assessing long-term trends by non-parametric Mann-Kendall technique. The trends are determined over the period of 1954-2003, which are also tested for significance. The results show that there are large intra-regional differences in the trends in different seasons. Local changes were found different from the large spatial scale averages in Kerala. Winter and autumn extreme rainfall were found having an increasing tendency with statistically significant changes in some regions indicating more occurrences of winter and autumn floods. On the other hand the spring seasonal extreme rainfall showed decreasing trends, which together with increasing frequency of the dry days is mainly affecting the total seasonal precipitation, which mainly point towards the vulnerability of Kerala to increasing probability of water scarcity in the pre-monsoon time and a delaying monsoon onset. Overall, the results of this study are good indicators of local climate changes over the five decades that will assist in seasonal forecasting and risk management.

  13. Diagnosing streamflow trends to understand ecohydrologic sensitivity and feedbacks to climate change in the mountain west

    Science.gov (United States)

    Luce, C.

    2010-12-01

    Shifts in climate may have negative consequences to forest vegetation in the mountains of the western U.S. Given our knowledge of the effects of land management on the hydrologic cycle, there is an expectation for feedbacks to streamflow from vegetation changes as well. Several recent papers reveal historical streamflow declines and increases in interannual variability in the western U.S. Although uncertainty in precipitation representation in GCM's makes the direct connection between streamflow changes and anthropogenic greenhouse gas accumulation unclear, we can gain insights about sensitivity of the ecohydroclimatic system to change by looking more carefully at the declines of the last half-century and their connection to other trends. One theory is that streaflow declines result from increased evapotranspiration caused by increased forest stocking and warmer air temperatures. The relative contribution of transpiration increases versus precipitation decreases is important, because it indicates the degree to which vegetation feedbacks could ameliorate declining streamflows. The distinction is also critical because precipitation trends may reverse while temperature trends are not expected to. Consideration of theoretical and empirical relationships from the Budyko curve and decades of small watershed experiments would suggest that if increased evaporative demand is driving observed streamflow declines, we should expect the greatest declines in wet years. Examination of the trends in dry years versus wet years across 43 stations in the Pacific Northwest, however, suggests that evapotranspiration changes may be small relative to precipitation driven changes. These results are confirmed with observations from a large paired basin with major vegetation changes from wildfire. Contrasting these results with precipitation observations across the region, however, raises difficult questions, including the potential need for more detailed screening for non-stationarity from

  14. Decadal surface water quality trends under variable climate, land use, and hydrogeochemical setting in Iowa, USA

    Science.gov (United States)

    Green, Christopher T.; Bekins, Barbara A.; Kalkhoff, Stephen J.; Hirsch, Robert M.; Liao, Lixia; Barnes, Kimberlee K.

    2014-01-01

    Understanding how nitrogen fluxes respond to changes in agriculture and climate is important for improving water quality. In the midwestern United States, expansion of corn cropping for ethanol production led to increasing N application rates in the 2000s during a period of extreme variability of annual precipitation. To examine the effects of these changes, surface water quality was analyzed in 10 major Iowa Rivers. Several decades of concentration and flow data were analyzed with a statistical method that provides internally consistent estimates of the concentration history and reveals flow-normalized trends that are independent of year-to-year streamflow variations. Flow-normalized concentrations of nitrate+nitrite-N decreased from 2000 to 2012 in all basins. To evaluate effects of annual discharge and N loading on these trends, multiple conceptual models were developed and calibrated to flow-weighted annual concentrations. The recent declining concentration trends can be attributed to both very high and very low discharge in the 2000s and to the long (e.g., 8 year) subsurface residence times in some basins. Dilution of N and depletion of stored N occurs in years with high discharge. Reduced N transport and increased N storage occurs in low-discharge years. Central Iowa basins showed the greatest reduction in flow-normalized concentrations, likely because of smaller storage volumes and shorter residence times. Effects of land-use changes on the water quality of major Iowa Rivers may not be noticeable for years or decades in peripheral basins of Iowa, and may be obscured in the central basins where extreme flows strongly affect annual concentration trends.

  15. Decadal surface water quality trends under variable climate, land use, and hydrogeochemical setting in Iowa, USA

    Science.gov (United States)

    Green, Christopher T.; Bekins, Barbara A.; Kalkhoff, Stephen J.; Hirsch, Robert M.; Liao, Lixia; Barnes, Kimberlee K.

    2014-03-01

    Understanding how nitrogen fluxes respond to changes in agriculture and climate is important for improving water quality. In the midwestern United States, expansion of corn cropping for ethanol production led to increasing N application rates in the 2000s during a period of extreme variability of annual precipitation. To examine the effects of these changes, surface water quality was analyzed in 10 major Iowa Rivers. Several decades of concentration and flow data were analyzed with a statistical method that provides internally consistent estimates of the concentration history and reveals flow-normalized trends that are independent of year-to-year streamflow variations. Flow-normalized concentrations of nitrate+nitrite-N decreased from 2000 to 2012 in all basins. To evaluate effects of annual discharge and N loading on these trends, multiple conceptual models were developed and calibrated to flow-weighted annual concentrations. The recent declining concentration trends can be attributed to both very high and very low discharge in the 2000s and to the long (e.g., 8 year) subsurface residence times in some basins. Dilution of N and depletion of stored N occurs in years with high discharge. Reduced N transport and increased N storage occurs in low-discharge years. Central Iowa basins showed the greatest reduction in flow-normalized concentrations, likely because of smaller storage volumes and shorter residence times. Effects of land-use changes on the water quality of major Iowa Rivers may not be noticeable for years or decades in peripheral basins of Iowa, and may be obscured in the central basins where extreme flows strongly affect annual concentration trends.

  16. Trends in African dust transport to the Caribbean: African sources, changing climate, and future scenarios

    Science.gov (United States)

    Prospero, J. M.

    2012-12-01

    Aerosol studies were begun on Barbados in 1965 and in Miami in 1974 and they continue to this day. This continuous record of daily measurements shows great variability in dust concentrations on time scales ranging from days to decades. Most notable was the great increase in dust concentrations in the early 1970s, apparently in response to drought in West Africa. Increased dust could impact a number of climate processes and human health in the Caribbean Basin. Indeed, in recent decades the dust concentrations over the Caribbean often exceed the US EPA standards for respirable particles. Thus there is concern over possible health impacts in the present day and how these might change in the future in response to climate change in Africa. It is logical to link of increased dust with drought. Indeed, over much of the Barbados record there was a strong negative correlation between dust concentrations and rainfall in the Sahel-Soudano (SS) region of North Africa. However, in retrospect this correlation was largely driven by three distinct periods in the early record: the period of high rainfall and low dust transport in the mid-to-late 1960s; the first drought in the early 1970s; and the extremely intense drought of the early 1980s. During this period, there seemed to be promising relationships between transport and various climate indices: e.g., El Niño, NAO, AMO. However, since the early 1990s there have been large year-to-year changes in SS rainfall but there is no consistent relationship to dust on Barbados or between dust and common climate indices. Furthermore, over the entire record there is a strong shift in seasonal dust transport, most notably, a great increase in winter and spring transport compared to the pre-drought and early drought period. These trends seem to suggest that there have been profound long-term changes in dust emissions and transport. A possible contributing factor could be increased population and land use in the SS region where over the past

  17. Cambios climáticos y vegetacionales inferidos a partir de paleofloras cenozoicas del sur de Sudamérica Climatic and vegetational changes inferred from Cenozoic Southern Southamerica paleoflora

    Directory of Open Access Journals (Sweden)

    Luis F Hinojosa

    2005-01-01

    Full Text Available Se presenta una reconstrucción del clima continental del sur de Sudamérica, sobre la base de un análisis fisionómico foliar de 15 tafofloras, provenientes en su mayoría de yacimientos de Chile y Argentina. A partir de las estimaciones climáticas obtenidas y la composición fitogeográfica, se postula la sucesión temporal de cuatro nuevas paleofloras: Gondwánica; Subtropical Gondwánica; Mixta; y Subtropical Neógena. Los resultados indican que las tafofloras del Cenozoico se asocian a por lo menos tres escenarios climáticos contrastantes : 1- condiciones tropicales relacionadas a un evento cálido y húmedo del Paleoceno/Eoceno, asociadas a las Paleofloras Gondwánica y Subtropical Gondwánica; 2- cambio hacia condiciones más templadas y secas hacia el final del Eoceno y principios del Oligoceno, relacionado con el evento de enfriamiento global del límite Eoceno/Oligoceno (consecuencia de la glaciación Antártica. Durante este tiempo habría imperado la Paleoflora Mixta; 3- finalmente, durante el Mioceno un nuevo evento cálido húmedo, durante el cual la temperatura media anual aumentó entre 6 y 9°C comparado con el período anterior. Este período de calentamiento está relacionado con el óptimo climático del Mioceno Medio y se caracteriza por el desarrollo de la Paleoflora Subtropical NeógenaA reconstruction of the continental climate of southern South America, based on physiognomic analyses of fifteen taphofloras, coming mainly from Chile and Argentina, is presented here. Based on the climate estimates and the phytogeographical composition of the Cenozoic paleofloras analyzed, the succession of four new Paleofloras is proposed: Gondwanic; Subtropical Gondwanic; Mixed and Subtropical Neogene Paleoflora. The results indicate that these paleofloras are, at least, related with three major paleoclimatic scenarios: 1- Paleocene/Eocene, warm and humid tropical conditions, associated with both Gondwanic and Subtropic Gondwanic

  18. Modulation of Late Cretaceous and Cenozoic climate by variable drawdown of atmospheric pCO2 from weathering of basaltic provinces on continents drifting through the equatorial humid belt

    Directory of Open Access Journals (Sweden)

    D. V. Kent

    2013-03-01

    -feedback mechanism that (usually inhibits the complete collapse of atmospheric pCO2 is the accelerating formation of thick cation-deficient soils that retard chemical weathering of the underlying bedrock. Nevertheless, equatorial climate seems to be relatively insensitive to pCO2 greenhouse forcing and thus with availability of some rejuvenating relief as in arc terranes or thick basaltic provinces, silicate weathering in this venue is not subject to a strong negative feedback, providing an avenue for ice ages. The safety valve that prevents excessive atmospheric pCO2 levels is the triggering of silicate weathering of continental areas and basaltic provinces in the temperate humid belt. Excess organic carbon burial seems to have played a negligible role in atmospheric pCO2 over the Late Cretaceous and Cenozoic.

  19. Modulation of Late Cretaceous and Cenozoic climate by variable drawdown of atmospheric pCO2 from weathering of basaltic provinces on continents drifting through the equatorial humid belt

    Directory of Open Access Journals (Sweden)

    G. Muttoni

    2012-09-01

    -feedback mechanism that (usually inhibits the complete collapse of atmospheric pCO2 is the accelerating formation of thick cation-deficient soils that retard chemical weathering of the underlying bedrock. Nevertheless, equatorial climate seems to be relatively insensitive to pCO2 greenhouse forcing and thus with availability of some rejuvenating relief as in arc terranes or thick basaltic provinces, silicate weathering in this venue is not subject to a strong negative feedback, providing an avenue for sporadic ice ages. The safety valve that prevents excessive atmospheric pCO2 levels is the triggering of silicate weathering of continental areas and basaltic provinces in the temperate humid belt. Increase in Mg/Ca ratio of seawater over the Cenozoic may be due to weathering input from continental basaltic provinces.

  20. 21st Century Trends in Antarctic Temperature and Polar Stratospheric Cloud (PSC) Area in the GEOS Chemistry-Climate Model

    Science.gov (United States)

    Hurwitz, M. M.; Newman, P. A.

    2010-01-01

    This study examines trends in Antarctic temperature and APSC, a temperature proxy for the area of polar stratospheric clouds, in an ensemble of Goddard Earth Observing System (GEOS) chemistry-climate model (CCM) simulations of the 21st century. A selection of greenhouse gas, ozone-depleting substance, and sea surface temperature scenarios is used to test the trend sensitivity to these parameters. One scenario is used to compare temperature trends in two versions of the GEOS CCM. An extended austral winter season is examined in detail. In May, June, and July, the expected future increase in CO2-related radiative cooling drives temperature trends in the Antarctic lower stratosphere. At 50 hPa, a 1.3 K cooling is expected between 2000 and 2100. Ozone levels increase, despite this robust cooling signal and the consequent increase in APSC, suggesting the enhancement of stratospheric transport in future. In the lower stratosphere, the choice of climate change scenarios does not affect the magnitude of the early winter cooling. Midwinter temperature trends are generally small. In October, APSC trends have the same sign as the prescribed halogen trends. That is, there are negative APSC trends in "grealistic future" simulations, where halogen loading decreases in accordance with the Montreal Protocol and CO2 continues to increase. In these simulations, the speed of ozone recovery is not influenced by either the choice of sea surface temperature and greenhouse gas scenarios or by the model version.

  1. Precipitation trends over the Korean peninsula: typhoon-induced changes and a typology for characterizing climate-related risk

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong-Suk [School of Energy and Environment, City University of Hong Kong, Hong Kong, People' s Republic of China (China); Jain, Shaleen, E-mail: shaleen.jain@maine.edu [Department of Civil and Environmental Engineering, University of Maine, Orono, ME 04469-5711 (United States)

    2011-07-15

    Typhoons originating in the west Pacific are major contributors to climate-related risk over the Korean peninsula. The current perspective regarding improved characterization of climatic risk and the projected increases in the intensity, frequency, duration, and power dissipation of typhoons during the 21st century in the western North Pacific region motivated a reappraisal of historical trends in precipitation. In this study, trends in the magnitude and frequency of seasonal precipitation in the five major river basins in Korea are analyzed on the basis of a separation analysis, with recognition of moisture sources (typhoon and non-typhoon). Over the 1966-2007 period, typhoons accounted for 21-26% of seasonal precipitation, with the largest values in the Nakdong River Basin. Typhoon-related precipitation events have increased significantly over portions of Han, Nakdong, and Geum River Basins. Alongside broad patterns toward increases in the magnitude and frequency of precipitation, distinct patterns of trends in the upper and lower quartiles (corresponding to changes in extreme events) are evident. A trend typology-spatially resolved characterization of the combination of shifts in the upper and lower tails of the precipitation distribution-shows that a number of sub-basins have undergone significant changes in one or both of the tails of the precipitation distribution. This broader characterization of trends illuminates the relative role of causal climatic factors and an identification of 'hot spots' likely to experience high exposure to typhoon-related climatic extremes in the future.

  2. Precipitation trends over the Korean peninsula: typhoon-induced changes and a typology for characterizing climate-related risk

    International Nuclear Information System (INIS)

    Typhoons originating in the west Pacific are major contributors to climate-related risk over the Korean peninsula. The current perspective regarding improved characterization of climatic risk and the projected increases in the intensity, frequency, duration, and power dissipation of typhoons during the 21st century in the western North Pacific region motivated a reappraisal of historical trends in precipitation. In this study, trends in the magnitude and frequency of seasonal precipitation in the five major river basins in Korea are analyzed on the basis of a separation analysis, with recognition of moisture sources (typhoon and non-typhoon). Over the 1966-2007 period, typhoons accounted for 21-26% of seasonal precipitation, with the largest values in the Nakdong River Basin. Typhoon-related precipitation events have increased significantly over portions of Han, Nakdong, and Geum River Basins. Alongside broad patterns toward increases in the magnitude and frequency of precipitation, distinct patterns of trends in the upper and lower quartiles (corresponding to changes in extreme events) are evident. A trend typology-spatially resolved characterization of the combination of shifts in the upper and lower tails of the precipitation distribution-shows that a number of sub-basins have undergone significant changes in one or both of the tails of the precipitation distribution. This broader characterization of trends illuminates the relative role of causal climatic factors and an identification of 'hot spots' likely to experience high exposure to typhoon-related climatic extremes in the future.

  3. Repository Profiles for Atmospheric and Climate Sciences: Capabilities and Trends in Data Services

    Science.gov (United States)

    Hou, C. Y.; Thompson, C. A.; Palmer, C. L.

    2014-12-01

    As digital research data proliferate and expectations for open access escalate, the landscape of data repositories is becoming more complex. For example, DataBib currently identifies 980 data repositories across the disciplines, with 117 categorized under Geosciences. In atmospheric and climate sciences, there are great expectations for the integration and reuse of data for advancing science. To realize this potential, resources are needed that explicate the range of repository options available for locating and depositing open data, their conditions of access and use, and the services and tools they provide. This study profiled 38 open digital repositories in the atmospheric and climate sciences, analyzing each on 55 criteria through content analysis of their websites. The results provide a systematic way to assess and compare capabilities, services, and institutional characteristics and identify trends across repositories. Selected results from the more detailed outcomes to be presented: Most repositories offer guidance on data format(s) for submission and dissemination. 42% offer authorization-free access. More than half use some type of data identification system such as DOIs. Nearly half offer some data processing, with a similar number providing software or tools. 78.9% request that users cite or acknowledge datasets used and the data center. Only 21.1% recommend specific metadata standards, such as ISO 19115 or Dublin Core, with more than half utilizing a customized metadata scheme. Information was rarely provided on repository certification and accreditation and uneven for transfer of rights and data security. Few provided policy information on preservation, migration, reappraisal, disposal, or long-term sustainability. As repository use increases, it will be important for institutions to make their procedures and policies explicit, to build trust with user communities and improve efficiencies in data sharing. Resources such as repository profiles will be

  4. Trends in climatic variables and future reference evapotranspiration in Duero Valley (Spain

    Directory of Open Access Journals (Sweden)

    R. Moratiel

    2011-06-01

    Full Text Available The impact of climate change and its relation with evapotranspiration was evaluated in the Duero River Basin (Spain. The study shows possible future situations 50 yr from now from the reference evapotranspiration (ETo. The maximum temperature (Tmax, minimum temperature (Tmin, dew point (Td, wind speed (U and net radiation (Rn trends during the 1980–2009 period were obtained and extrapolated with the FAO-56 Penman-Montheith equation to estimate ETo. Changes in stomatal resistance in response to increases in CO2 were also considered. Four scenarios were done, taking the concentration of CO2 and the period analyzed (annual or monthly into consideration. The scenarios studied showed the changes in ETo as a consequence of the annual and monthly trends in the variables Tmax, Tmin, Td, U and Rn with current and future CO2 concentrations (372 ppm and 550 ppm. The future ETo showed increases between 118 mm (11 % and 55 mm (5 % with respect to the current situation of the river basin at 1042 mm. The months most affected by climate change are May, June, July, August and September, which also coincide with the maximum water needs of the basin's crops.

  5. Wave climate in the Arctic 1992-2014: seasonality, trends, and wave-ice influence

    Science.gov (United States)

    Girard-Ardhuin, Fanny; Stopa, Justin; Ardhuin, Fabrice

    2016-04-01

    The diminishing sea ice has direct implications on the wave field which is mainly dependent on the ice-free area and wind. Over the past decade, the Arctic sea ice has diminished which directly impacts the wave field. This study characterizes the wave climate in the Arctic using detailed sea state information from a wave hindcast and merged altimeter dataset spanning 1992-2014. The waves are driven by winds from the Climate Forecast System Reanalysis. Ice concentrations derived from satellites with a grid spacing of 12.5 km are sufficiently able to resolve important features in the marginal ice zone. Before implementation, suitable wind forcing is identified and the validity and consistency of the wave hindcast is verified with altimeters. The seasonal ice advance and retreat largely dictates the waves and creates distinct features in the wind-waves and swells. The Nordic-Greenland Sea is dominated by swells from the North Atlantic while the coastal regions and semi-enclosed seas of the Kara, Laptev, Chukchi, and Beaufort have a more equal proportion of wind-waves and swells. Trends in the altimeters and model are in agreement and show increasing wave activities in the Baffin Bay, Beaufort, Chukchi, Laptev, and Kara Seas due to the loss of sea ice. In the Nordic-Greenland Sea, there is a decreasing trend related to changes in the wind field by North Atlantic Oscillation. The waves also influence the sea ice. Two distinctly different wave-ice environments are identified and selected events demonstrate the importance of waves in the marginal ice zone. The crux of the research identifies the need for continued study and improvement of wave-ice interaction.

  6. Report on ICDP workshop CONOSC (COring the NOrth Sea Cenozoic)

    Science.gov (United States)

    Westerhoff, Wim; Donders, Timme; Luthi, Stefan

    2016-08-01

    ICDP workshop COring the NOrth Sea Cenozoic focused on the scientific objectives and the technical aspects of drilling and sampling. Some 55 participants attended the meeting, ranging from climate scientists, drilling engineers, and geophysicists to stratigraphers and public outreach experts. Discussion on the proposed research sharpened the main research lines and led to working groups and the necessary technical details to compile a full proposal that was submitted in January 2016.

  7. Understanding the recent trend of haze pollution in eastern China: roles of climate change

    Science.gov (United States)

    Wang, Hui-Jun; Chen, Huo-Po

    2016-04-01

    In this paper, the variation and trend of haze pollution in eastern China for winter of 1960-2012 were analyzed. With the overall increasing number of winter haze days in this period, the 5 decades were divided into three sub-periods based on the changes of winter haze days (WHD) in central North China (30-40° N) and eastern South China (south of 30° N) for east of 109° E mainland China. Results show that WHD kept gradually increasing during 1960-1979, remained stable overall during 1980-1999, and increased fast during 2000-2012. The author identified the major climate forcing factors besides total energy consumption. Among all the possible climate factors, variability of the autumn Arctic sea ice extent, local precipitation and surface wind during winter is most influential to the haze pollution change. The joint effect of fast increase of total energy consumption, rapid decline of Arctic sea ice extent and reduced precipitation and surface winds intensified the haze pollution in central North China after 2000. There is a similar conclusion for haze pollution in eastern South China after 2000, with the precipitation effect being smaller and spatially inconsistent.

  8. Climate change trend and its effects on reference evapotranspiration at Linhe Station, Hetao Irrigation District

    Directory of Open Access Journals (Sweden)

    Xu-ming WANG

    2014-07-01

    Full Text Available Linhe National Meteorological Station, a representative weather station in the Hetao Irrigation District of China, was selected as the research site for the present study. Changes in climatic variables and reference evapotranspiration (ET0 (estimated by the Penman-Monteith method were detected using Mann-Kendall tests and Sen’s slope estimator, respectively. The authors analyzed the relationship between the change and each climatic variable’s change. From 1954 to 2012, the air temperature showed a significant increasing trend, whereas relative humidity and wind speed decreased dramatically. These changes resulted in a slight increase in . The radiative component of total increased from 50% to 57%, indicating that this component made a greater contribution to the increase in total than the aerodynamic component, especially during the crop growing season (from April to October. The sensitivity analysis showed that in Hetao is most sensitive to mean daily air temperature (11.8%, followed by wind speed (−7.3% and relative humidity (4.8%. Changes in sunshine duration had only a minor effect on over the past 59 years.

  9. Inference of Global Mean Temperature Trend and Climate Change from MSU and AMSU

    Science.gov (United States)

    Prabhakara, Cuddapah; Iacovazzi, R. A., Jr.; Yoo, J.-M.; Lau, William K. M. (Technical Monitor)

    2001-01-01

    Microwave Sounding Unit (MSU) and Advanced MSU (AMSU) radiometers flown on the NOAA operational satellite series are potentially valuable as global temperature monitoring devices. Spencer and Christy pioneered the analysis of mid-tropospheric temperature, given by MSU Channel 2 (Ch 2) at 53.74 GHz, to derive the global temperature trend. Also, in addition to monitoring global temperature, these microwave radiometers have the potential to reveal interannual climate signals in tropics. We have analyzed the data of MSU Ch 2 and AMSU Ch 5 (53.6 GHz) from the NOAA operational satellites for the period 1980 to 2000, utilizing the NOAA calibration procedure. The data are corrected for the satellite orbital drift based on the temporal changes of the on-board warm blackbody temperature. From our analysis, we find that the global temperature increased at a rate of 0.13 +/- 0.05 Kdecade(sup -1) during 1980 to 2000. From an Empirical Orthogonal Function (EOF) analysis of the MSU global data, we find that the mid-tropospheric temperature in middle and high latitudes responds to the ENSO forcing during the Northern Hemisphere Winter in a distinct manner. This mid-latitude response is opposite in phase to that in the tropics. This result is in accord with simulations performed with an ECMWF global spectral model. This study shows a potential use of the satellite observations for climatic change.

  10. Management and climate contributions to satellite-derived active fire trends in the contiguous United States

    Science.gov (United States)

    Lin, Hsiao-Wen; McCarty, Jessica L.; Wang, Dongdong; Rogers, Brendan M.; Morton, Douglas C.; Collatz, G. James; Jin, Yufang; Randerson, James T.

    2014-04-01

    Fires in croplands, plantations, and rangelands contribute significantly to fire emissions in the United States, yet are often overshadowed by wildland fires in efforts to develop inventories or estimate responses to climate change. Here we quantified decadal trends, interannual variability, and seasonality of Terra Moderate Resolution Imaging Spectroradiometer (MODIS) observations of active fires (thermal anomalies) as a function of management type in the contiguous U.S. during 2001-2010. We used the Monitoring Trends in Burn Severity database to identify active fires within the perimeter of large wildland fires and land cover maps to identify active fires in croplands. A third class of fires defined as prescribed/other included all residual satellite active fire detections. Large wildland fires were the most variable of all three fire types and had no significant annual trend in the contiguous U.S. during 2001-2010. Active fires in croplands, in contrast, increased at a rate of 3.4% per year. Cropland and prescribed/other fire types combined were responsible for 77% of the total active fire detections within the U.S and were most abundant in the south and southeast. In the west, cropland active fires decreased at a rate of 5.9% per year, likely in response to intensive air quality policies. Potential evaporation was a dominant regulator of the interannual variability of large wildland fires, but had a weaker influence on the other two fire types. Our analysis suggests it may be possible to modify landscape fire emissions within the U.S. by influencing the way fires are used in managed ecosystems.

  11. Conservation in metropolitan regions: assessing trends and threats of urban development and climate change

    Science.gov (United States)

    Thorne, J. H.; Santos, M. J.; Bjorkman, J.

    2011-12-01

    Two global challenges to successful conservation are urban expansion and climate change. Rapid urban growth threatens biodiversity and associated ecosystem services, while climate change may make currently protected areas unsuitable for species that exist within them. We examined three measures of landscape change for 8800 km2 of the San Francisco Bay metropolitan region over 80 years past and future: urban growth, protected area establishment, and natural vegetation type extents. The Bay Area is a good test bed for conservation assessment of the impacts of temporal and spatial of urban growth and land cover change. The region is geographically rather small, with over 40% of its lands already dedicated to protected park and open space lands, they are well-documented, and, the area has had extensive population growth in the past and is projected to continue to grow. The ten-county region within which our study area is a subset has grown from 1.78 million people in 1930, to 6.97 million in 2000 and is estimated to grow to 10.94 million by 2050. With such an influx of people into a small geographic area, it is imperative to both examine the past urban expansion and estimate how the future population will be accommodated into the landscape. We quantify these trends to assess conservation 'success' through time. We used historical and current landcover maps to assess trend, and a GIS-based urban modeling (UPlan) to assess future urban growth impacts in the region, under three policy scenarios- business as usual, smart growth, and urban redevelopment. Impacts are measured by the amount of open space targeted by conservation planners in the region that will be urbanized under each urban growth policy. Impacts are also measured by estimates of the energy consumption projected for each of the scenarios on household and business unit level. The 'business as usual' and 'smart growth' scenarios differed little in their impacts to targeted conservation lands, because so little

  12. Analysis of trend changes in Northern African palaeo-climate by using Bayesian inference

    Science.gov (United States)

    Schütz, Nadine; Trauth, Martin H.; Holschneider, Matthias

    2010-05-01

    Climate variability of Northern Africa is of high interest due to climate-evolutionary linkages under study. The reconstruction of the palaeo-climate over long time scales, including the expected linkages (> 3 Ma), is mainly accessible by proxy data from deep sea drilling cores. By concentrating on published data sets, we try to decipher rhythms and trends to detect correlations between different proxy time series by advanced mathematical methods. Our preliminary data is dust concentration, as an indicator for climatic changes such as humidity, from the ODP sites 659, 721 and 967 situated around Northern Africa. Our interest is in challenging the available time series with advanced statistical methods to detect significant trend changes and to compare different model assumptions. For that purpose, we want to avoid the rescaling of the time axis to obtain equidistant time steps for filtering methods. Additionally we demand an plausible description of the errors for the estimated parameters, in terms of confidence intervals. Finally, depending on what model we restrict on, we also want an insight in the parameter structure of the assumed models. To gain this information, we focus on Bayesian inference by formulating the problem as a linear mixed model, so that the expectation and deviation are of linear structure. By using the Bayesian method we can formulate the posteriori density as a function of the model parameters and calculate this probability density in the parameter space. Depending which parameters are of interest, we analytically and numerically marginalize the posteriori with respect to the remaining parameters of less interest. We apply a simple linear mixed model to calculate the posteriori densities of the ODP sites 659 and 721 concerning the last 5 Ma at maximum. From preliminary calculations on these data sets, we can confirm results gained by the method of breakfit regression combined with block bootstrapping ([1]). We obtain a significant change

  13. Impact of climate change on UK estuaries: A review of past trends and potential projections

    Science.gov (United States)

    Robins, Peter E.; Skov, Martin W.; Lewis, Matt J.; Giménez, Luis; Davies, Alan G.; Malham, Shelagh K.; Neill, Simon P.; McDonald, James E.; Whitton, Timothy A.; Jackson, Suzanna E.; Jago, Colin F.

    2016-02-01

    UK estuarine environments are regulated by inter-acting physical processes, including tidal, wave, surge, river discharge and sediment supply. They regulate the fluxes of nutrients, pollutants, pathogens and viruses that determine whether coastlines achieve the Good Environmental Status (GEnS) required by the EU's Marine Strategy Directive. We review 20th century trends and 21st century projections of changes to climatic drivers, and their potential for altering estuarine bio-physical processes. Sea-level rise will cause some marine habitats to expand, and others diminish in area extent. The overall consequences of estuarine morphodynamics to these habitat shifts, and vice-versa, are unknown. Increased temperatures could intensify microbial pathogen concentrations and increase public health risk. The patterns of change of other climatic drivers are difficult to predict (e.g., river flows and storm surges). Projected increased winter river flows throughout UK catchments will enhance the risks of coastal eutrophication, harmful algal blooms and hypoxia in some contexts, although there are spatial variabilities in river flow projections. The reproductive success of estuarine biota is sensitive to saline intrusion and corresponding turbidity maxima, which are projected to gradually shift landwards as a result of sea-level rise. Although more-frequent flushing events in winter and longer periods of drought in summer are predicted, whereby the subsequent estuarine mixing and recovery rates are poorly understood. With rising estuarine salinities, subtidal species can penetrate deeper into estuaries, although this will depend on the resilience/adaptation of the species. Many climate and impact predictions lack resolution and spatial cover. Long-term monitoring and increased research, which considers the catchment-river-estuary-coast system as a whole, is needed to support risk predicting and mitigatory strategies.

  14. Diverse growth trends and climate responses across Eurasia’s boreal forest

    Science.gov (United States)

    Hellmann, Lena; Agafonov, Leonid; Charpentier Ljungqvist, Fredrik; Churakova (Sidorova, Olga; Düthorn, Elisabeth; Esper, Jan; Hülsmann, Lisa; Kirdyanov, Alexander V.; Moiseev, Pavel; Myglan, Vladimir S.; Nikolaev, Anatoly N.; Reinig, Frederick; Schweingruber, Fritz H.; Solomina, Olga; Tegel, Willy; Büntgen, Ulf

    2016-07-01

    The area covered by boreal forests accounts for ∼16% of the global and 22% of the Northern Hemisphere landmass. Changes in the productivity and functioning of this circumpolar biome not only have strong effects on species composition and diversity at regional to larger scales, but also on the Earth’s carbon cycle. Although temporal inconsistency in the response of tree growth to temperature has been reported from some locations at the higher northern latitudes, a systematic dendroecological network assessment is still missing for most of the boreal zone. Here, we analyze the geographical patterns of changes in summer temperature and precipitation across northern Eurasia >60 °N since 1951 AD, as well as the growth trends and climate responses of 445 Pinus, Larix and Picea ring width chronologies in the same area and period. In contrast to widespread summer warming, fluctuations in precipitation and tree growth are spatially more diverse and overall less distinct. Although the influence of summer temperature on ring formation is increasing with latitude and distinct moisture effects are restricted to a few southern locations, growth sensitivity to June–July temperature variability is only significant at 16.6% of all sites (p ≤ 0.01). By revealing complex climate constraints on the productivity of Eurasia’s northern forests, our results question the a priori suitability of boreal tree-ring width chronologies for reconstructing summer temperatures. This study further emphasizes regional climate differences and their role on the dynamics of boreal ecosystems, and also underlines the importance of free data access to facilitate the compilation and evaluation of massively replicated and updated dendroecological networks.

  15. Dengue Fever Trends and Climate Change in San Juan, Puerto Rico

    Science.gov (United States)

    Muller-Karger, F. E.; Mendez-Lazaro, P.; Otis, D. B.; McCarthy, M.; Pena-Orellana, M.

    2014-12-01

    Climate change has important implications for public health. We developed and tested the hypothesis that conditions for dengue fever transmission in San Juan (Puerto Rico, USA) are becoming favorable as a result of meteorological drivers being modified with climate change. Sea level pressure, mean sea level (MSL), wind, sea surface temperature (SST), air surface temperature (AST), rainfall, and confirmed dengue cases were variables examined over the past 30 years, or longer for some variables. Statistical tools used included Principal Component Analysis, Pearson correlation coefficient, Mann-Kendall trend tests, and logistic regressions. Results show that dry days are increasing and that wet days are decreasing. MSL is steadily increasing, which increases the risk of dengue cases along the coast, as the perimeter of the San Juan Bay estuary expands and the shoreline moves inland. Warming is evident in both SST and AST. Maximum and minimum air surface temperature extremes have also increased. Incidence of dengue is accelerating along with environmental change. For example, between 2000-2011, dengue transmission increased by a factor of 3.4 (95% CI: 1.9-6.1) for each 1ºC increase in SST. Between 2007 and 2011, this risk factor increased to 5.2 (95% CI: 1.9-13.9) for every 1ºC increase in SST. An important but difficult to examine problem is how social and economic factors affect such dengue fever transmission rates in light of environmental change. A concern is that the patterns observed in San Juan are representative of potential incidence of dengue virus in other parts of the island of Puerto Rico and in other Caribbean nations. These results help understand patterns of disease spreading, and allow public health officials to evaluate scenarios and interventions intended to mitigate the impacts of climate change.

  16. A century of climate and ecosystem change in Western Montana: What do temperature trends portend?

    Science.gov (United States)

    Pederson, G.T.; Graumlich, L.J.; Fagre, D.B.; Kipfer, T.; Muhlfeld, C.C.

    2010-01-01

    The physical science linking human-induced increases in greenhouse gasses to the warming of the global climate system is well established, but the implications of this warming for ecosystem processes and services at regional scales is still poorly understood. Thus, the objectives of this work were to: (1) describe rates of change in temperature averages and extremes for western Montana, a region containing sensitive resources and ecosystems, (2) investigate associations between Montana temperature change to hemispheric and global temperature change, (3) provide climate analysis tools for land and resource managers responsible for researching and maintaining renewable resources, habitat, and threatened/endangered species and (4) integrate our findings into a more general assessment of climate impacts on ecosystem processes and services over the past century. Over 100 years of daily and monthly temperature data collected in western Montana, USA are analyzed for long-term changes in seasonal averages and daily extremes. In particular, variability and trends in temperature above or below ecologically and socially meaningful thresholds within this region (e.g., -17.8??C (0??F), 0??C (32??F), and 32.2??C (90??F)) are assessed. The daily temperature time series reveal extremely cold days (??? -17.8??C) terminate on average 20 days earlier and decline in number, whereas extremely hot days (???32??C) show a three-fold increase in number and a 24-day increase in seasonal window during which they occur. Results show that regionally important thresholds have been exceeded, the most recent of which include the timing and number of the 0??C freeze/thaw temperatures during spring and fall. Finally, we close with a discussion on the implications for Montana's ecosystems. Special attention is given to critical processes that respond non-linearly as temperatures exceed critical thresholds, and have positive feedbacks that amplify the changes. ?? Springer Science + Business Media B

  17. From Oil Crisis to Climate Change. Understanding CO2 Emission Trends in IEA Countries

    International Nuclear Information System (INIS)

    OECD CO2 emissions from fuel combustion increased 13% between 1990 and 2001. This signals an important shift since, over the 1973 to 1990 period, emissions only increased by 3.4%. As a result, CO2 emissions from energy use (fuel combustion) contributed 81.1% of total OECD greenhouse gas emissions in 2001 compared to 77.7% in 1990. As these figures make clear, reducing CO2 emissions from fuel combustion constitutes a key challenge to combat climate change. Developing and successfully implementing the most efficient policies for reducing CO2 emissions requires a good understanding of how factors such as income, prices, demography, economic structure, lifestyle, climate, energy efficiency and fuel mix affect energy use and resulting CO2 emissions. This paper presents selected results from the analysis of CO2 developments included in the IEA publication 'From Oil Crisis to Climate Challenge: 30 Years of Energy Use in IEA Countries'. The paper gives a brief overview of aggregate CO2 emission trends and of how recent developments in selected IEA countries compare to emissions levels implied by the Kyoto targets. A deeper understanding of the aggregate trends is provided by showing results from a decomposition analysis and by discussing developments in key end-use sectors. The full publication presents a more detailed analysis of how various factors have shaped energy use patterns and CO2 emissions since 1973. The analysis draws on a newly developed database with detailed information on energy use in the manufacturing, household, service and transport sectors. The database represents the most disaggregated information available on a consistent basis across countries and sectors. The study uses quantitative measures to illustrate the forces that drive or restrain energy use. These measures - or indicators - include: activities such as manufacturing output or heated-floor-area of homes; structural developments such as changes in manufacturing output mix or changes in the

  18. Climate-driven trends in the occurrence of major floods across North America and Europe

    Science.gov (United States)

    Hodgkins, Glenn A.; Whitfield, Paul H.; Burn, Donald H.; Hannaford, Jamie; Renard, Benjamin; Stahl, Kerstin; Fleig, Anne K.; Madsen, Henrik; Mediero, Luis; Korhonen, Johanna; Murphy, Conor; Crochet, Philippe; Wilson, Donna

    2016-04-01

    Every year river floods cause enormous damage around the world. Recent major floods in North America and Europe, for example, have received much press, with some concluding that these floods are more frequent in recent years as a result of anthropogenic warming. There has been considerable scientific effort invested in establishing whether observed flood records show evidence of trends or variability in flood frequency, and to determine whether these patterns can be linked to climatic changes. However, the river catchments used in many published studies are influenced by direct human alteration such as reservoir regulation and urbanisation, which can confound the interpretation of climate-driven variability. Furthermore, a majority of previous studies have analysed changes in low magnitude floods, such as the annual peak flow, at a national scale. Few studies are known that have analysed changes in large floods (greater than 25-year floods) on a continental scale. To fill this research gap, we present a study analysing flood flows from reference hydrologic networks (RHNs) or RHN-like gauges across a large study domain embracing North America and much of Europe. RHNs comprise gauging stations with minimally disturbed catchment conditions, which have a near-natural flow regime and provide good quality data; RHN analyses thus allow hydro-climatic variability to be distinguished from direct artificial disturbances or data inhomogeneities. One of the key innovations in this study is the definition of an RHN-like network consisting of 1204 catchments on a continental scale. The network incorporates existing, well-established RHNs in Canada, the US, the UK, Ireland and Norway, alongside RHN-like catchments from Europe (France, Switzerland, Iceland, Denmark, Sweden, Finland, Spain), which have been incorporated in the network following a major effort to ensure RHN-like status of candidate gauges through consultation with local experts. As the aim of the study is to examine

  19. Atmospheric circulation influence on climatic trends in Europe: an analysis of circulation type classifications from the COST733 catalogue

    Czech Academy of Sciences Publication Activity Database

    Cahynová, Monika; Huth, Radan

    -, - (2016). ISSN 0899-8418 Institutional support: RVO:68378289 ; RVO:67179843 Keywords : atmospheric circulation * classification * circulation type * climatic trends * Europe * COST733 Impact factor: 3.157, year: 2014 http://onlinelibrary.wiley.com/doi/10.1002/joc.4003/abstract

  20. Climate and hydrological changes in the northeastern United States: recent trends and implications for forested and aquatic ecosystems

    Science.gov (United States)

    Huntington, Thomas G.; Richardson, Andrew D.; McGuire, Kevin J.; Hayhoe, Katharine

    2009-01-01

    We review twentieth century and projected twenty-first century changes in climatic and hydrologic conditions in the northeastern United States and the implications of these changes for forest ecosystems. Climate warming and increases in precipitation and associated changes in snow and hydrologic regimes have been observed over the last century, with the most pronounced changes occurring since 1970. Trends in specific climatic and hydrologic variables differ in their responses spatially (e.g., coastal vs. inland) and temporally (e.g., spring vs. summer). Trends can differ depending on the period of record analyzed, hinting at the role of decadal-scale climatic variation that is superimposed over the longer-term trend. Model predictions indicate that continued increases in temperature and precipitation across the northeastern United States can be expected over the next century. Ongoing increases in growing season length (earlier spring and later autumn) will most likely increase evapotranspiration and frequency of drought. In turn, an increase in the frequency of drought will likely increase the risk of fire and negatively impact forest productivity, maple syrup production, and the intensity of autumn foliage coloration. Climate and hydrologic changes could have profound effects on forest structure, composition, and ecological functioning in response to the changes discussed here and as described in related articles in this issue of the Journal.

  1. Annual trend patterns of phytoplankton species abundance belie homogeneous taxonomical group responses to climate in the NE Atlantic upwelling.

    Science.gov (United States)

    Bode, Antonio; Estévez, M Graciela; Varela, Manuel; Vilar, José A

    2015-09-01

    Phytoplankton is a sentinel of marine ecosystem change. Composed by many species with different life-history strategies, it rapidly responds to environment changes. An analysis of the abundance of 54 phytoplankton species in Galicia (NW Spain) between 1989 and 2008 to determine the main components of temporal variability in relation to climate and upwelling showed that most of this variability was stochastic, as seasonality and long term trends contributed to relatively small fractions of the series. In general, trends appeared as non linear, and species clustered in 4 groups according to the trend pattern but there was no defined pattern for diatoms, dinoflagellates or other groups. While, in general, total abundance increased, no clear trend was found for 23 species, 14 species decreased, 4 species increased during the early 1990s, and only 13 species showed a general increase through the series. In contrast, series of local environmental conditions (temperature, stratification, nutrients) and climate-related variables (atmospheric pressure indices, upwelling winds) showed a high fraction of their variability in deterministic seasonality and trends. As a result, each species responded independently to environmental and climate variability, measured by generalized additive models. Most species showed a positive relationship with nutrient concentrations but only a few showed a direct relationship with stratification and upwelling. Climate variables had only measurable effects on some species but no common response emerged. Because its adaptation to frequent disturbances, phytoplankton communities in upwelling ecosystems appear less sensitive to changes in regional climate than other communities characterized by short and well defined productive periods. PMID:26283032

  2. Trend of surface solar radiation over Asia simulated by aerosol transport-climate model

    Science.gov (United States)

    Takemura, T.; Ohmura, A.

    2009-12-01

    Long-term records of surface radiation measurements indicate a decrease in the solar radiation between the 1950s and 1980s (“global dimming”), then its recovery afterward (“global brightening”) at many locations all over the globe [Wild, 2009]. On the other hand, the global brightening is delayed over the Asian region [Ohmura, 2009]. It is suggested that these trends of the global dimming and brightening are strongly related with a change in aerosol loading in the atmosphere which affect the climate change through the direct, semi-direct, and indirect effects. In this study, causes of the trend of the surface solar radiation over Asia during last several decades are analyzed with an aerosol transport-climate model, SPRINTARS. SPRINTARS is coupled with MIROC which is a general circulation model (GCM) developed by Center for Climate System Research (CCSR)/University of Tokyo, National Institute for Environmental Studies (NIES), and Frontier Research Center for Global Change (FRCGC) [Takemura et al., 2000, 2002, 2005, 2009]. The horizontal and vertical resolutions are T106 (approximately 1.1° by 1.1°) and 56 layers, respectively. SPRINTARS includes the transport, radiation, cloud, and precipitation processes of all main tropospheric aerosols (black and organic carbons, sulfate, soil dust, and sea salt). The model treats not only the aerosol mass mixing ratios but also the cloud droplet and ice crystal number concentrations as prognostic variables, and the nucleation processes of cloud droplets and ice crystals depend on the number concentrations of each aerosol species. Changes in the cloud droplet and ice crystal number concentrations affect the cloud radiation and precipitation processes in the model. Historical emissions, that is consumption of fossil fuel and biofuel, biomass burning, aircraft emissions, and volcanic eruptions are prescribed from database provided by the Aerosol Model Intercomparison Project (AeroCom) and the latest IPCC inventories

  3. Climate-influenced ponderosa pine (Pinus ponderosa seed masting trends in western Montana, USA

    Directory of Open Access Journals (Sweden)

    Christopher R. Keyes

    2015-04-01

    Full Text Available Aim of study: The aim of this study was to analyze 10-year records of ponderosa pine (Pinus ponderosa seed production, in order to confirm synchronic seed production and to evaluate cyclical masting trends, masting depletion effect, and climate-masting relationships. Area of study: The study area was located in a P. ponderosa stand in the northern Rocky Mountains (western Montana, USA. Material and methods: The study was conducted in one stand that had been subjected to a silvicultural study of uneven-aged management techniques that was carried out in 1984, and which resulted in three separate units consisting of one control, one cut/no-burn treatment, and one cut/burn treatment. Seeds were collected during the 10 years following treatment in 15 traps systematically deployed within each of the stand’s three units. The total numbers of seeds collected in each unit were plotted over time to analyze crop synchrony, with Spearman rank correlation coefficient used to test for masting cycles and crop depletion after a mast year. Meteorological records over the period 1983-1994 were related to the occurrence of a mast event (defined as crops exceeding 50,000 viable seeds/ha. Main results: The seed production pattern was non-cyclical, synchronous, and independent of silvicultural treatment history. A mast-depletion effect was evident but was not statistically significant. Mast events seem to be promoted by the occurrence of optimum mean temperatures at the beginning of spring during both the first (11 °C and second (9 °C years of cone maturation. The probability of a mast year was also affected by summer temperature (number of late frost days; negative effect and precipitation amount (positive effect. All these factors would seemingly explain the observed synchronous pattern in cone production. Research highlights: The non-cyclical trend of ponderosa pine seed mast years is influenced by specific climate determinants. Fluctuations in mean early

  4. Patterns of Cenozoic sediment flux from western Scandinavia

    DEFF Research Database (Denmark)

    Gołędowski, Bartosz; Nielsen, S.B.; Clausen, O.R.

    2012-01-01

    tectonism, climate and climate change. Western Scandinavia, the northern British Isles and the Faeroe-Shetland Platform were significant sediment sources during the Paleocene, which is well founded in tectonic causes related to the opening of the North Atlantic. From the Eocene and onward, variations in the...... sediment flux from western Scandinavia correlate better with climate and climate change. During the Eocene, sediment production was low. From the late Eocene onward, increased seasonality may have contributed to stimulating the sediment flux. Significant climatic cooling episodes correlate with Oligocene......The significance of variations in the sediment flux from western Scandinavia during the Cenozoic has been a matter of debate for decades. Here we compile the sediment flux using seismic data, boreholes and results from other publications and discuss the relative importance of causal agents such as...

  5. Cenozoic carbon cycle imbalances and a variable weathering feedback

    Science.gov (United States)

    Caves, Jeremy K.; Jost, Adam B.; Lau, Kimberly V.; Maher, Kate

    2016-09-01

    The long-term stability of Earth's climate and the recovery of the ocean-atmosphere system after carbon cycle perturbations are often attributed to a stabilizing negative feedback between silicate weathering and climate. However, evidence for the operation of this feedback over million-year timescales and in response to tectonic and long-term climatic change remains scarce. For example, the past 50 million years of the Cenozoic Era are characterized by long-term cooling and declining atmospheric CO2 (pCO2). During this interval, constant or decreasing carbon fluxes from the solid Earth to the atmosphere suggest that stable or decreasing weathering fluxes are needed to balance the carbon cycle. In contrast, marine isotopic proxies of weathering (i.e., 87Sr/86Sr, δ7 Li , and 187Os/188Os) are interpreted to reflect increasing weathering fluxes. Here, we evaluate the existence of a negative feedback by reconstructing the imbalance in the carbon cycle during the Cenozoic using the surface inventories of carbon and alkalinity. Only a sustained 0.25-0.5% increase in silicate weathering is necessary to explain the long-term decline in pCO2 over the Cenozoic. We propose that the long-term decrease in pCO2 is due to an increase in the strength of the silicate weathering feedback (i.e., the constant of proportionality between the silicate weathering flux and climate), rather than an increase in the weathering flux. This increase in the feedback strength, which mirrors the marine isotope proxies, occurs as transient, 1 million year timescales remains invariant to match the long-term inputs of carbon. Over the Cenozoic, this results in stable long-term weathering fluxes even as pCO2 decreases. We attribute increasing feedback strength to a change in the type and reactivity of rock in the weathering zone, which collectively has increased the reactivity of the surface of the Earth. Increasing feedback strength through the Cenozoic reconciles mass balance in the carbon cycle with

  6. Urban partnerships in low-carbon development: Opportunities and challenges of an emerging trend in global climate politics

    Directory of Open Access Journals (Sweden)

    Jan Beermann

    2014-05-01

    Full Text Available This study explores the linkages between two recent trends in global climate governance. The first trend is the growing focus on cities in the multi-level governance of climate change. Whereas international climate change negotiations often end in deadlock, many urban centers across the world are taking the lead. Industrialized cities from the Global North and increasingly cities from the emerging Southern economies are experimenting with innovative and ambitious programs to reduce their local carbon footprints. A second trend is the expan¬ding urban North-South cooperation in the area of low-carbon development. This cooperation takes various forms, such as city twinning, transnational municipal networks and trans-local development cooperation. A key target of these initiatives is to develop joint projects and exchange knowledge to foster low-carbon development pathways. This study analyzes the conditions of success and failure in selected Indo-German urban low-carbon partnerships with a particular focus on institutional arrangements. The paper presents evidence from three initiatives and argues that successful trans-local cooperation depends largely on the interplay between institutional forms and the development of social capital. Building on these findings, the paper discusses what lessons may be drawn from the emergence of urban North-South cooperation for the future development of global climate governance.

  7. Zoning vulnerability of climate change in variation of amount and trend of precipitation - Case Study: Great Khorasan province

    Science.gov (United States)

    Modiri, Ehsan; Modiri, Sadegh

    2015-04-01

    Climatic hazards have complex nature that many of them are beyond human control. Earth's climate is constantly fluctuating and trying to balance itself. More than 75% of Iran has arid and semi-arid climate thus assessment of climate change induced threats and vulnerabilities is essential. In order to investigate the reason for the changes in amount and trend of precipitation parameter, 17 synoptic stations have been selected in the interval of the establishment time of the station until 2013. These stations are located in three regions: Northern, Razavi and Southern Khorasan. For quality control of data in Monthly, quarterly and annual total precipitation of data were tested and checked by run test. Then probable trends in each of the areas was assessed by Kendall-tau test. Total annual precipitation of each station is the important factor that increase the sensitivity of vulnerability in the area with low rainfall. Annual amount of precipitation moving from north to south has been declining, though in different fields that they have different geomorphologic characteristics controversies occur. But clearly can be observed average of precipitation decline with decreasing latitude. There were positive trends in the annual precipitation in 6 stations, negative trends in 10 stations, as well as one station, has no trend. The remarkable notice is that all stations have a positive trend were in the northern region in the case study. These stations had been in ranging from none to Moderate classification of threats and vulnerability. After the initialization parameters to classify levels of risks and vulnerability, the two measures of mean annual precipitation and the trends of this fluctuation were combined together. This classification was created in five level for stations. Accordingly Golmakan, Ghochan, Torbate heydarieh, Bojnord and Mashhad were in none threat level. Khoor of Birjand and Boshruyeh have had complete stage of the threat level and had the greatest

  8. Evaluation of surface air temperature trend and climate change in the north - east of I. R. of Iran

    International Nuclear Information System (INIS)

    In this paper maximum, minimum and mean surface air temperature recorded, analysed to reveal spatial and temporal patterns of long-term trends, change points, significant warming (cooling) periods and linear trend per decade. According to this research summer minimum temperatures have generally increased at a larger rate than in spring and autumn minimum temperatures. On the other hand, nighttime warming rates of spring and summer are generally stronger than those that exist in spring and summer daytime temperatures. Considering the significant increasing trends in annual, spring and summer temperatures, it is seen that night-time warming rates are stronger in the northern regions, which are characterized by the Khorasan Province macro climate type: a very hot summer, a relatively hot and late spring and early autumn, and a moderate winter. We have seriously considered the strong warming trends in spring and summer and thus likely in annual minimum air temperatures. It is very likely that significant and very rapid night-time warming trends over much of the province can be related to the widespread, rapid and increased urbanization in Khorasan Province, in addition to long-term and global effects of the human-induced climate change on air temperatures. (Author)

  9. Extreme Climate Event Trends: The Data Mining and Evaluation of the A1FI Scenario for 2000???2100

    Energy Technology Data Exchange (ETDEWEB)

    Erickson III, David J [ORNL; Ganguly, Auroop R [ORNL; Steinhaeuser, Karsten J K [ORNL; Branstetter, Marcia L [ORNL; Oglesby, Robert [University of Nebraska, Lincoln; Hoffman, Forrest M [ORNL; Buja, Lawrence [National Center for Atmospheric Research (NCAR)

    2008-01-01

    The authors discuss the implications and resulting alterations of the hydrologic cycle as Earth climate evolves from 2000-2100. Climate simulations based on the assumptions implicit in the A1F1 scenario for the period 2000-2100 using CCSM3 are analyzed. In particular, we will assess the changes in the surface latent and sensible heat energy budget, the Indian regional water budgets including trends in the timing and duration of the Indian monsoon and the resulting impacts on mean river flow and hydroelectric power generation potential. These analyses will also be examined within the context of heat index, droughts, floods and related estimates of societal robustness and resiliency. We will interpret these new A1F1 results within the context of the previous climate simulations based on the SRES A2 and B1 scenarios forced with land cover and atmospheric CO2. Analyses of historical records in the context of the Indian Monsoon Rainfall (IMR) have suggested an evolving relation of IMR with natural climate variability caused by El Nino events. We will report on the combined effects of natural climate variability and global warming on IMR and assess the trend of extreme rain and temperature events in a warming environment.

  10. Key trends of climate change in the ASEAN countries. The IPAT decomposition analysis 1980-2005

    Energy Technology Data Exchange (ETDEWEB)

    Vehmas, J.; Luukkanen, J.; Kaivo-oja, J.; Panula-Ontto, J.; Allievi, F.

    2012-07-01

    has been widely recognized. Energy and climate policy planning requires in-depth analyses of current trends and structures of energy production systems and related emission flows. Possibilities to reduce greenhouse gas emissions depend critically on economic growth and on the development of energy efficiency in economywide production systems. The ASEAN Leaders have expressed their concern and commitment for ASEAN to play a proactive role in addressing climate change through their declarations to the 2007 Bali and 2009 Copenhagen UN Conferences on Climate Change. They view the protection of the environment and the sustainable use and management of natural resources as essential to the long-term economic growth and social development of countries in the region. The ASEAN Vision 2020 calls for 'a clean and green ASEAN' with fully established mechanisms to ensure the protection of the environment, sustainability of natural resources, and high quality of life of people in the region. ASEAN Leaders have noted that: 'We acknowledged the energy cooperation between ASEAN and Japan in promoting energy efficiency and conservation as well as new and renewable energy, and stressed the need for closer cooperation. The ASEAN Leaders welcomed Japan's efforts to create a low-carbon society. We appreciated Thailand's offer for the use of the Practical Energy Management Training Center in Thailand which was established with funding from Japan to other ASEAN Member States interested in energy conservation in factories.' Thus, low carbon society is key energy policy target of ASEAN countries. Our analysis in this e-book gives analytical background to this strategy. This e-book also indicates that ASEAN countries have very different kind of challenges for low carbon strategy. The e-book provides useful information for ASEAN energy policy formulation and implementation of the Bali Roadmap. This study presents a comparative analysis of the driving forces behind

  11. Local climate policy in practice. Use of the playing field, impact of trends and the integration of climate care in municipal policy

    International Nuclear Information System (INIS)

    The result of the first research phase of the project was an outline of the playing field of local climate policy. The use of options and instruments from the playing field is examined on the basis of literature and interviews with local governments. In the process, barriers for the implementation of options are illustrated. The evaluation of the playing field in practise shows that local governments often only use part of their playing field. Even local governments that excel and are familiar throughout the country in relation to one particular task area ignore other task areas. The reasons why options and instruments are not fully utilised vary per task area: not enough internal support; lack of clear policy framework; climate policy must join in with other targets or local governments depend on cooperation of other actors. Nevertheless, generally speaking the success and failure factors in utilising options in the local government playing field are often related to the sphere of cooperation with other parties and the input of knowledge in the organisation of the local government. Moreover, the importance of climate is not made explicit enough in many task areas. The options in climate policy for local governments are influenced by social developments. In the study three trends are examined with respect to their influence: developments in the area of liberalisation of the energy market, the position of local governments in national environmental policy and changes in local democracy. These trends result in a complication of the role of local governments. Local governments must show more initiative than in the past. Liberalisation leads to a more business-oriented relationship with energy companies and probably lower energy prices. Larger freedom of policy results in more space for establishing local priorities, but does not necessarily result in more attention for local climate policy. Participation can result in a larger support for climate policy but also

  12. Communicating confidence in the detection and attribution of trends relevant to climate change

    Science.gov (United States)

    Ebi, K. L.

    2015-12-01

    Readily understandable and consistent language for describing confidence in detection and attribution statements can be developed based on the approach used by the International Agency for Research on Cancer (IARC). IARC was founded in 1965 to provide government authorities with expert, independent, scientific opinion on the causes of human cancer. IARC developed four standard terms for evaluations of the strength of evidence for carcinogenicity arising from human and experimental animal data, and for the strength of mechanistic evidence. Evidence is categorized as sufficient, limited, inadequate, and lack of carcinogenicity. The IARC process then combines theory, evidence, and degree of agreement into a summary evaluation that includes concise statements of the principal line(s) of argument that emerged, the conclusions of the working group on the strength of the evidence for each group of studies, citations to indicate which studies were pivotal to these conclusions, and the reasons for any differential weighting of data. The summary IARC categories are: Group 1 for agents carcinogenic to humans; Group 2 includes Group 2A (probably carcinogenic to humans) or Group 2B (possibly carcinogenic to humans) on the basis of epidemiological and experimental evidence of carcinogenicity and mechanistic and other relevant data; Group 3 for agents is not classifiable as to its carcinogenicity to humans; and Group 4 for agents probably not carcinogenic to humans. There are obvious parallels with describing confidence in key findings on detection and attribution of a trend to anthropogenic climate change with the confidence statements used by the IARC. Developing and consistent application of similar categories along with accompanying explanations of the principal lines of evidence, would be a helpful step in clearing communicating the degree and sources of certainty in the findings of detection and attribution.

  13. Atmospheric circulation influence on climatic trends in Europe: an analysis of circulation type classifications from the COST733 catalogue

    Czech Academy of Sciences Publication Activity Database

    Cahynová, Monika; Huth, R.

    -, - (2016). ISSN 0899-8418 R&D Projects: GA ČR GAP209/10/2265; GA ČR(CZ) GPP209/12/P811 Institutional support: RVO:67179843 ; RVO:68378289 Keywords : atmospheric circulation * classification * circulation type * climatic trends * Europe * COST733 Subject RIV: EH - Ecology, Behaviour; DG - Athmosphere Sciences, Meteorology (UFA-U) Impact factor: 3.157, year: 2014

  14. Climate change effects on human health in a gender perspective: some trends in Arctic research

    OpenAIRE

    Natalia, Kukarenko

    2011-01-01

    Background Climate change and environmental pollution have become pressing concerns for the peoples in the Arctic region. Some researchers link climate change, transformations of living conditions and human health. A number of studies have also provided data on differentiating effects of climate change on women's and men's well-being and health. Objective To show how the issues of climate and environment change, human health and gender are addressed in current research in the Arctic. The main...

  15. Climate change effects on human health in a gender perspective: some trends in Arctic research

    OpenAIRE

    Kukarenko, Natalia

    2011-01-01

    Background: Climate change and environmental pollution have become pressing concerns for the peoples in the Arctic region. Some researchers link climate change, transformations of living conditions and human health. A number of studies have also provided data on differentiating effects of climate change on women’s and men’s well-being and health. Objective: To show how the issues of climate and environment change, human health and gender are addressed in current research in the Arctic. The ma...

  16. Characteristics of climatic trends and correlation between pan-evaporation and environmental factors in the last 40 years over China

    Institute of Scientific and Technical Information of China (English)

    ZUO Hongchao; LI Dongliang; HU Yinqiao; BAO Yan; L(U) Shihua

    2005-01-01

    Using the data observed by 62 Chinese Routine Meteorological Stations (CRMS) with long term radiation observation, the climatic trends and the relationship between pan-evaporation and its environmental factors are analyzed comprehensively. The results show that during the last 40 years, the relative humidity is uptrend in west China, downtrend in east China, and their extrema are 0.20%/a and -0.22%/a respectively; the precipitations of about 61% CRMS keep uptrend, its maximum can reach 10.52 mm/a2 while the cloud amounts of about 79% CRMS keep downtrend slightly. About 98% CRMS display the air temperature uptrend, and the maximum is 0.11℃/a. About 76% CRMS display the land surface temperature uptrend. About 87% CRMS show the daily range of temperature downtrend. The global radiations observed by about 85% CRMS and the 10 m wind speeds observed by about 77% CRMS hold downtrend. The annual pan-evaporations of about 66% CRMS hold descend trend, and the biggest descent reaches -24.9 mm/a2. The pan-evaporation has good relationship with many environmental factors, but the relationship with the relative humidity is the best. All of the climatic trends respond to the global climate changes.

  17. Spatiotemporal analysis of temperature trends under climate change in the source region of the Yellow River, China

    Science.gov (United States)

    Wang, Yuli; Wang, Xuan; Li, Chunhui; Wu, Feifei; Yang, Zhifeng

    2015-01-01

    Under global climate change, the change in temperature has greatly affected the hydrological processes and water resource security in the source region of the Yellow River, which is located in the Qinghai-Tibet Plateau and serves as a major source of domestic and agricultural water supply in the watershed. Multiple spatiotemporal analysis methods, including the S-mode empirical orthogonal function analysis, the inverse distance weighted interpolation, the weighted moving average method, and the Mann-Kendall test method were used to comprehensively analyze the temperatures of 14 meteorological stations at yearly and seasonal scales from 1961 to 2010. The results indicated that (1) general trends of temperature change have been rising, with an especially significant warming trend since the late 1990s; (2) in the last five decades, temperature trends in the study area underwent three stages, namely a cool stage (approximately 1961-1980), a fluctuating stage (approximately 1981-1997), and a warm stage (approximately 1998-2010); and (3) due to the combined effects of monsoons and geographic features, the source region could be divided into three zones according to the annual temperature variations: a low-value zone centered on Henan station in the northeastern edge; a high-value zone situated in the central, southern, and western area; and a transitional zone between the two zones mentioned above. This study is helpful for understanding temperature trends under climate change and can provide a basis for ecological protection.

  18. Variations and trends of terrestrial NPP and its relation to climate change in the 10 CMIP5 models

    Indian Academy of Sciences (India)

    Suosuo Li; Shihua Lü; Yuanpu Liu; Yanhong Gao; Yinhuan Ao

    2015-03-01

    Using global terrestrial ecosystem net primary productivity (NPP) data, we validated the simulated multi-model ensemble (MME) NPP, analyzed the spatial distribution of global NPP and explored the relationship between NPP and climate variations in historical scenarios of 10 CMIP5 models. The results show that the global spatial pattern of simulated terrestrial ecosystem NPP, is consistent with IGBP NPP, but the values have some differences and there is a huge uncertainty. Considering global climate change, near surface temperature is the major factor affecting the terrestrial ecosystem, followed by the precipitation. This means terrestrial ecosystem NPP is more closely related to near surface temperature than precipitation. Between 1976 and 2005, NPP shows an obvious increasing temporal trend, indicating the terrestrial ecosystem has had a positive response to climate change. MME NPP has increased 3.647PgC during historical period, which shows an increasing temporal trend of 3.9 gCm−2∙100 yr−2 in the past 150 years, also indicating that the terrestrial ecosystem has shown a positive response to climate change in past 150 years.

  19. Seasonal and Interannual Trends in Largest Cholera Endemic Megacity: Water Sustainability - Climate - Health Challenges in Dhaka, Bangladesh

    Science.gov (United States)

    Akanda, Ali S.; Jutla, Antarpreet; Faruque, Abu S. G.; Huq, Anwar; Colwell, Rita R.

    2014-05-01

    The last three decades of surveillance data shows a drastic increase of cholera prevalence in the largest cholera-endemic city in the world - Dhaka, Bangladesh. Emerging megacities in the region, especially those located in coastal areas also remain vulnerable to large scale drivers of cholera outbreaks. However, there has not been any systematic study on linking long-term disease trends with related changes in natural or societal variables. Here, we analyze the 30-year dynamics of urban cholera prevalence in Dhaka with changes in climatic or anthropogenic forcings: regional hydrology, flooding, water usage, changes in distribution systems, population growth and density in urban settlements, as well as shifting climate patterns and frequency of natural disasters. An interesting change is observed in the seasonal trends of cholera prevalence; while an endemic upward trend is seen in the dry season, the post-monsoon trend is epidemic in nature. In addition, the trend in the pre-monsoon dry season is significantly stronger than the post-monsoon wet season; and thus spring is becoming the dominant cholera season of the year. Evidence points to growing urbanization and rising population in unplanned settlements along the city peripheries. The rapid pressure of growth has led to an unsustainable and potentially disastrous situation with negligible-to-poor water and sanitation systems compounded by changing climatic patterns and increasing number of extreme weather events. Growing water scarcity in the dry season and lack of sustainable water and sanitation infrastructure for urban settlements have increased endemicity of cholera outbreaks in spring, while record flood events and prolonged post-monsoon inundation have contributed to increased epidemic outbreaks in fall. We analyze our findings with the World Health Organization recommended guidelines and investigate large scale water sustainability challenges in the context of climatic and anthropogenic changes in the

  20. Climatic trends in the North Atlantic region during the last 2,000 years in an orbitally forced AOGCM simulation

    Science.gov (United States)

    Wagner, S.; Zorita, E.

    2013-12-01

    The global coverage of temporal highly resolved proxy-based climate reconstructions is extending to cover the last 2,000 years. It is thus important to fully understand the effect of the orbital forcing at these time scales, as the imprint of the orbital forcing becomes clearer when analyzing climate on time scales longer than the last 1,000 years. The slow-varying orbital parameters affect the seasonal distribution of the incoming solar radiation. Although changes are not as pronounced compared to the mid-Holocene, still distinct differences exist, with lower insolation between February and May and higher insolation between July and October over the mid- and high northern latitudes 2,000 years ago compared to present. Here, we analyze a simulation with the coupled climate model ECHO-G forced only with changes in orbital variations for the last 2,000 years. Other factors such as solar activity and greenhouse gas changes are set to constant pre-industrial values. The modeled near-surface temperature trends reflect the expected orbitally induced insolation trends over the northern hemispheric continents and the Arctic, with increased temperatures during May and reduced temperatures during October. Over the North Atlantic Ocean, however SST trends are not directly consistent to changes in orbital forcing throughout the year, mostly showing little or slight uniform cooling trends. The strength of the maximum overturning circulation in the North Atlantic Ocean also shows no clear-cut trends that can be linked to changes in external forcings. Other variables related to oceanic convection and surface heat fluxes indicate, however, spatially heterogeneous trend patterns. For example, regions south of Greenland and off Labrador show increases in convection that compensate the decreases over the Labrador and the Norwegian Sea. This pattern varies in intensity and spatial extent between the different winter half year months. Changes in oceanic convection and surface heat

  1. Late Cenozoic Paleoceanography of the Central Arctic Ocean

    International Nuclear Information System (INIS)

    The Arctic Ocean is the smallest and perhaps least accessible of the worlds oceans. It occupies only 26% of the global ocean area, and less than 10% of its volume. However, it exerts a disproportionately large influence on the global climate system through a complex set of positive and negative feedback mechanisms directly or indirectly related to terrestrial ice and snow cover and sea ice. Increasingly, the northern high latitude cryosphere is seen as an exceptionally fragile part of the global climate system, a fact exemplified by observed reductions in sea ice extent during the past decades [2]. The paleoceanographic evolution of the Arctic Ocean can provide important insights into the physical forcing mechanisms that affect the form, intensity and permanence of ice in the high Arctic, and its sensitivity to these mechanisms in vastly different climate states of the past. However, marine records capturing the late Cenozoic paleoceanography of the Arctic are limited - most notably because only a single deep borehole exists from the central parts of this Ocean. This paper reviews the principal late Cenozoic (Neogene/Quaternary) results from the Arctic Coring Expedition to the Lomonosov Ridge and in light of recent data and observations on modern sea ice, outlines emerging questions related to three main themes: 1) the establishment of the 'modern' Arctic Ocean and the opening of the Fram Strait 2) the inception of perennial sea ice 3) The Quaternary intensification of Northern Hemisphere glaciations.

  2. Winter climate affects long-term trends in stream water nitrate in acid-sensitive catchments in southern Norway

    Directory of Open Access Journals (Sweden)

    H. A. de Wit

    2008-03-01

    Full Text Available Controls of stream water NO3 in mountainous and forested catchments are not thoroughly understood. Long-term trends in stream water NO3 are positive, neutral and negative, often apparently independent of trends in N deposition. Here, time series of NO3 in four small acid-sensitive catchments in southern Norway were analysed in order to identify likely drivers of long-term changes in NO3. In two sites, stream water NO3 export declined ca 50% over a period of 25 years while in the other sites NO3 export increased with roughly 20%. Discharge and N deposition alone were poor predictors of these trends. The most distinct trends in NO3 were found in winter and spring. Empirical models explained between 45% and 61% of the variation in weekly concentrations of NO3, and described both upward and downward seasonal trends tolerably well. Key explaining variables were snow depth, discharge, temperature and N deposition. All catchments showed reductions in snow depth and increases in winter discharge. In two inland catchments, located in moderate N deposition areas, these climatic changes appeared to drive the distinct decreases in winter and spring concentrations and fluxes of NO3. In a coast-near mountainous catchment in a low N deposition area, these climatic changes appeared to have the opposite effect, i.e. lead to increases in especially winter NO3. This suggests that the effect of a reduced snow pack may result in both decreased and increased catchment N leaching depending on interactions with N deposition, soil temperature regime and winter discharge.

  3. Winter climate affects long-term trends in stream water nitrate in acid-sensitive catchments in southern Norway

    Directory of Open Access Journals (Sweden)

    H. A. de Wit

    2007-09-01

    Full Text Available Controls of stream water NO3 in mountainous and forested catchments are not thoroughly understood. Long-term trends in stream water NO3 are positive, neutral and negative, often apparently independent of trends in N deposition. Here, time series of NO3 in four small acid-sensitive catchments in southern Norway were analysed in order to identify likely drivers of long-term changes in NO3. In two sites, stream water NO3 export declined ca 50% over a period of 25 years while in the other sites NO3 export increased with roughly 20%. Discharge and N deposition alone were poor predictors of these trends. The most distinct trends in NO3 were found in winter and spring. Empirical models explained between 45% and 61% of the variation in weekly concentrations of NO3, and described both upward and downward seasonal trends tolerably well. Key explaining variables were snow depth, discharge, temperature and N deposition. All catchments showed reductions in snow depth and increases in winter discharge. In two inland catchments, located in moderate N deposition areas, these climatic changes appeared to drive the distinct decreases in winter and spring concentrations and fluxes of NO3. In a coast-near mountainous catchment in a low N deposition area, these climatic changes appeared to have the opposite effect, i.e. lead to increases in especially winter NO3. This suggests that the effect of a reduced snow pack may result in both decreased and increased catchment N leaching depending on interactions with N deposition, soil temperature regime and winter discharge.

  4. The 13 million year Cenozoic pulse of the Earth

    Science.gov (United States)

    Chen, Jiasheng; Kravchinsky, Vadim A.; Liu, Xiuming

    2015-12-01

    The geomagnetic polarity reversal rate changes radically from very low to extremely high. Such process indicates fundamental changes in the Earth's core reorganization and core-mantle boundary heat flow fluctuations. However, we still do not know how critical such changes are to surface geology and climate processes. Our analysis of the geomagnetic reversal frequency, oxygen isotope record, and tectonic plate subduction rate, which are indicators of the changes in the heat flux at the core mantle boundary, climate and plate tectonic activity, shows that all these changes indicate similar rhythms on million years' timescale in the Cenozoic Era occurring with the common fundamental periodicity of ∼13 Myr during most of the time. The periodicity is disrupted only during the last 20 Myr. Such periodic behavior suggests that large scale climate and tectonic changes at the Earth's surface are closely connected with the million year timescale cyclical reorganization of the Earth's interior.

  5. Determining Water Quality Trends in the Sacramento-San Joaquin Delta Watershed in the Face of Climate Change

    Science.gov (United States)

    Kynett, K.; Azimi-Gaylon, S.; Doidic, C.

    2014-12-01

    The Sacramento-San Joaquin Delta and Suisun Marsh (Delta) is the largest estuary on the West Coast of the Americas and is a resource of local, State, and national significance. The Delta is simultaneously the most critical component of California's water supply, a primary focus of the state's ecological conservation measures, and a vital resource deeply imperiled by degraded water quality. Delta waterbodies are identified as impaired by salinity, excess nutrients, low dissolved oxygen, pathogens, pesticides, heavy metals, and other contaminants. Climate change is expected to exacerbate the impacts of existing stressors in the Delta and magnify the challenges of managing this natural resource. A clear understanding of the current state of the watershed is needed to better inform scientists, decision makers, and the public about potential impacts from climate change. The Delta Watershed Initiative Network (Delta WIN) leverages the ecological benefits of healthy watersheds, and enhances, expands and creates opportunities for greater watershed health by coordinating with agencies, established programs, and local organizations. At this critical junction, Delta WIN is coordinating data integration and analysis to develop better understanding of the existing and emerging water quality concerns. As first steps, Delta WIN is integrating existing water quality data, analyzing trends, and monitoring to fill data gaps and to evaluate indicators of climate change impacts. Available data will be used for trend analysis; Delta WIN will continue to monitor where data is incomplete and new questions arise. Understanding how climate change conditions may affect water quality will be used to inform efforts to build resilience and maintain water quality levels which sustain aquatic life and human needs. Assessments of historical and new data will aid in recognition of potential climate change impacts and in initiating implementation of best management practices in collaboration with

  6. Disentangling the relative importance of changes in climate and land-use intensity in driving recent bird population trends.

    Directory of Open Access Journals (Sweden)

    Sarah M Eglington

    Full Text Available Threats to biodiversity resulting from habitat destruction and deterioration have been documented for many species, whilst climate change is regarded as increasingly impacting upon species' distribution and abundance. However, few studies have disentangled the relative importance of these two drivers in causing recent population declines. We quantify the relative importance of both processes by modelling annual variation in population growth of 18 farmland bird species in the UK as a function of measures of land-use intensity and weather. Modelled together, both had similar explanatory power in accounting for annual fluctuations in population growth. When these models were used to retrodict population trends for each species as a function of annual variation in land-use intensity and weather combined, and separately, retrodictions incorporating land-use intensity were more closely linked to observed population trends than retrodictions based only on weather, and closely matched the UK farmland bird index from 1970 onwards. Despite more stable land-use intensity in recent years, climate change (inferred from weather trends has not overtaken land-use intensity as the dominant driver of bird populations.

  7. Climatic trends over the Tibetan Plateau during 1971-2000%1971-2000年青藏高原气候变化趋势

    Institute of Scientific and Technical Information of China (English)

    吴绍洪; 尹云鹤; 郑度; 杨勤业

    2007-01-01

    Trends of annual and monthly temperature, precipitation, potential evapotranspiration and aridity index were analyzed to understand climate change during the period 1971-2000 over the Tibetan Plateau which is one of the most special regions sensitive to global climate change. FAO56-Penmen-Monteith model was modified to calculate potential evapotranspiration which integrated many climatic elements including maximum and minimum temperatures, solar radiation, relative humidity and wind speed. Results indicate generally warming trends of the annual averaged and monthly temperatures, increasing trends of precipitation except in April and September, decreasing trends of annual and monthly potential evapotranspiration, and increasing aridity index except in September. It is not the isolated climatic elements that are important to moisture conditions, but their integrated and simultaneous effect. Moreover, potential evapotranspiration often changes the effect of precipitation on moisture conditions. The climate trends suggest an important warm and humid tendency averaged over the southern plateau in annual period and in August. Moisture conditions would probably get drier at large area in the headwater region of the three rivers in annual average and months from April to November, and the northeast of the plateau from July to September. Complicated climatic trends over the Tibetan Plateau reveal that climatic factors have nonlinear relationships, and resulte in much uncertainty together with the scarcity of observation data. The results would enhance our understanding of the potential impact of climate change on environment in the Tibetan Plateau. Further research of the sensitivity and attribution of climate change to moisture conditions on the plateau is necessary.

  8. Climatic and technological ceilings for Chinese rice stagnation based on yield gaps and yield trend pattern analysis.

    Science.gov (United States)

    Zhang, Tianyi; Yang, Xiaoguang; Wang, Hesong; Li, Yong; Ye, Qing

    2014-04-01

    Climatic or technological ceilings could cause yield stagnation. Thus, identifying the principal reasons for yield stagnation within the context of the local climate and socio-economic conditions are essential for informing regional agricultural policies. In this study, we identified the climatic and technological ceilings for seven rice-production regions in China based on yield gaps and on a yield trend pattern analysis for the period 1980-2010. The results indicate that 54.9% of the counties sampled experienced yield stagnation since the 1980. The potential yield ceilings in northern and eastern China decreased to a greater extent than in other regions due to the accompanying climate effects of increases in temperature and decreases in radiation. This may be associated with yield stagnation and halt occurring in approximately 49.8-57.0% of the sampled counties in these areas. South-western China exhibited a promising scope for yield improvement, showing the greatest yield gap (30.6%), whereas the yields were stagnant in 58.4% of the sampled counties. This finding suggests that efforts to overcome the technological ceiling must be given priority so that the available exploitable yield gap can be achieved. North-eastern China, however, represents a noteworthy exception. In the north-central area of this region, climate change has increased the yield potential ceiling, and this increase has been accompanied by the most rapid increase in actual yield: 1.02 ton ha(-1) per decade. Therefore, north-eastern China shows a great potential for rice production, which is favoured by the current climate conditions and available technology level. Additional environmentally friendly economic incentives might be considered in this region. PMID:24130084

  9. Evidence for a climate signal in trends of global crop yield variability over the past 50 years

    International Nuclear Information System (INIS)

    Low variability of crop production from year to year is desirable for many reasons, including reduced income risk and stability of supplies. Therefore, it is important to understand the nature of yield variability, whether it is changing through time, and how it varies between crops and regions. Previous studies have shown that national crop yield variability has changed in the past, with the direction and magnitude dependent on crop type and location. Whilst such studies acknowledge the importance of climate variability in determining yield variability, it has been assumed that its magnitude and its effect on crop production have not changed through time and, hence, that changes to yield variability have been due to non-climatic factors. We address this assumption by jointly examining yield and climate variability for three major crops (rice, wheat and maize) over the past 50 years. National yield time series and growing season temperature and precipitation were de-trended and related using multiple linear regression. Yield variability changed significantly in half of the crop–country combinations examined. For several crop–country combinations, changes in yield variability were related to changes in climate variability. (letter)

  10. Biodiversity in a changing climate: a synthesis of current and projected trends in the US

    Science.gov (United States)

    Staudinger, Michelle D.; Carter, Shawn L.; Cross, Molly S.; Dubois, Natalie S.; Duffy, J. Emmett; Enquist, Carolyn; Griffis, Roger; Hellmann, Jessica J.; Lawler, Joshua J.; O’Leary, John; Morrison, Scott A.; Sneddon, Lesley; Stein, Bruce A.; Thompson, Laura M.; Turner, Woody

    2013-01-01

    This paper provides a synthesis of the recent literature describing how global biodiversity is being affected by climate change and is projected to respond in the future. Current studies reinforce earlier findings of major climate-change-related impacts on biological systems and document new, more subtle after-effects. For example, many species are shifting their distributions and phenologies at faster rates than were recorded just a few years ago; however, responses are not uniform across species. Shifts have been idiosyncratic and in some cases counterintuitive, promoting new community compositions and altering biotic interactions. Although genetic diversity enhances species' potential to respond to variable conditions, climate change may outpace intrinsic adaptive capacities and increase the relative vulnerabilities of many organisms. Developing effective adaptation strategies for biodiversity conservation will not only require flexible decision-making and management approaches that account for uncertainties in climate projections and ecological responses but will also necessitate coordinated monitoring efforts.

  11. Montane ecosystem productivity responds more to global circulation patterns than climatic trends

    International Nuclear Information System (INIS)

    Regional ecosystem productivity is highly sensitive to inter-annual climate variability, both within and outside the primary carbon uptake period. However, Earth system models lack sufficient spatial scales and ecosystem processes to resolve how these processes may change in a warming climate. Here, we show, how for the European Alps, mid-latitude Atlantic ocean winter circulation anomalies drive high-altitude summer forest and grassland productivity, through feedbacks among orographic wind circulation patterns, snowfall, winter and spring temperatures, and vegetation activity. Therefore, to understand future global climate change influence to regional ecosystem productivity, Earth systems models need to focus on improvements towards topographic downscaling of changes in regional atmospheric circulation patterns and to lagged responses in vegetation dynamics to non-growing season climate anomalies. (letter)

  12. Precipitation Trend Analysis over Eastern Region of India Using Cmip5 Based Climatic Models

    OpenAIRE

    Kundu, A; Dwivedi, S.; Chandra, V

    2014-01-01

    Climate science is a complex field as climate is governed by processes that interact and operate on a vast array of time and space scales. The processes involving radiative transfer, chemistry and phase changes of water are most easily described at atomic and molecular scales; the influence of ice sheets, continents and planetary scale circulations controlling the basic energy balance of the planet operate at continental scales; even planetary orbital and solar variations operating a...

  13. Spatial synchrony of local populations has increased in association with the recent Northern Hemisphere climate trend

    OpenAIRE

    Post, Eric; Forchhammer, Mads C.

    2004-01-01

    According to ecological theory, populations whose dynamics are entrained by environmental correlation face increased extinction risk as environmental conditions become more synchronized spatially. This prediction is highly relevant to the study of ecological consequences of climate change. Recent empirical studies have indicated, for example, that large-scale climate synchronizes trophic interactions and population dynamics over broad spatial scales in freshwater and terrestrial systems. Here...

  14. Review of monsoons, interannual variability and decadal trends that underpin climate prediction

    OpenAIRE

    Susanto, D.; Vinayachandran, P.; Hacker, P.; Masumoto, Y.; Webster, P.; Godfrey, S; Meyers, G

    2002-01-01

    Understanding and predicting the interannual variations of the whole monsoon climate system has been, and will continue to be, one of the major reasons for studying the oceanography of the Indian Ocean; but there are other reasons. Knowledge about Indian Ocean current systems may have diverse practical applications, from fisheries through search and rescue to management of Exclusive Economic Zones. Our discussion mainly concerns the open ocean and the climate applications, but the resul...

  15. Climate Change Vulnerability and Resilience: Current Status and Trends for Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ibarraran , Maria E.; Malone, Elizabeth L.; Brenkert, Antoinette L.

    2008-12-30

    Climate change alters different localities on the planet in different ways. The impact on each region depends mainly on the degree of vulnerability that natural ecosystems and human-made infrastructure have to changes in climate and extreme meteorological events, as well as on the coping and adaptation capacity towards new environmental conditions. This study assesses the current resilience of Mexico and Mexican states to such changes, as well as how this resilience will look in the future. In recent studies (Moss et al. 2000, Brenkert and Malone 2005, Malone and Brenket 2008, Ibarrarán et al. 2007), the Vulnerability-Resilience Indicators Model (VRIM) is used to integrate a set of proxy variables that determine the resilience of a region to climate change. Resilience, or the ability of a region to respond to climate variations and natural events that result from climate change, is given by its adaptation and coping capacity and its sensitivity. On the one hand, the sensitivity of a region to climate change is assessed, emphasizing its infrastructure, food security, water resources, and the health of the population and regional ecosystems. On the other hand, coping and adaptation capacity is based on the availability of human resources, economic capacity and environmental capacity.

  16. Algal constraints on the Cenozoic history of atmospheric CO2?

    Directory of Open Access Journals (Sweden)

    R. E. M. Rickaby

    2007-01-01

    Full Text Available An urgent question for future climate, in light of increased burning of fossil fuels, is the temperature sensitivity of the climate system to atmospheric carbon dioxide (pCO2. To date, no direct proxy for past levels of pCO2 exists beyond the reach of the polar ice core records. We propose a new methodology for placing an upper constraint on pCO2 over the Cenozoic based on the living geological record. Specifically, our premise is that the contrasting calcification tolerance of various extant species of coccolithophore to raised pCO2 reflects an "evolutionary memory" of past atmospheric composition. The different times of first emergence of each morphospecies allows an upper constraint of past pCO2 to be placed on Cenozoic timeslices. Further, our hypothesis has implications for the response of marine calcifiers to ocean acidification. Geologically "ancient" species, which have survived large changes in ocean chemistry, are likely more resilient to predicted acidification.

  17. Dual scale trend analysis to evaluate climatic and anthropogenic effects on the vegetated land surface in agricultural Russia

    Science.gov (United States)

    de Beurs, Kirsten; Henebry, Geoffrey

    2010-05-01

    Russia's population is projected to shrink by a staggering 29% by 2050. Differential dynamics among rural populations are correlated with ethnicity and constitute a key driver in the spatial disintegration of rural Russia. Currently, Russia is slowly transitioning into a country with an internal "archipelago" of islands of productive agriculture around cities set within a matrix of much less productive and abandoned croplands. This heterogeneous spatial pattern is mainly driven by depopulation of the least favorable parts of the countryside, where "least favorable" is some function of lower fertility of land, higher remoteness from urban markets, or both. Our aim is to improve current understanding of the interactions of climate change and the spatio-temporal impacts of agricultural reform in European Russia. We present a dual scale trend analysis to characterize change in agricultural European Russia. We selected a global NASA MODIS product (MCD43C4 and MCD43A4) at a 0.05° (~5.6 km) and 500m spatial resolution and a 16-day temporal resolution from 2000 through 2008. We applied a refinement of the Seasonal Kendal trend method to Normalized Difference Vegetation Index (NDVI) image series at both scales. We only incorporated composites during the vegetative growing season which was delineated by start of season and end of season estimates based on analysis of Normalized Difference Infrared Index (NDII) data. Trend patterns revealed areas of increasing NDVI trend in Russia which was linked through the dual scale analysis with agricultural land cover change. The coarser scale analysis was relevant to atmospheric boundary layer processes, while the finer scale data revealed trends that were more relevant to human decision-making and regional economics. We evaluated the weather patterns and land surface phenologies for the areas with increasing NDVI over the past 9 years and compared the results with agricultural areas without change. This analysis improved our

  18. Effects of variable climate, land use, and hydrogeochemical setting on decadal surface water quality trends, Iowa, USA

    Science.gov (United States)

    Green, C. T.; Bekins, B. A.; Kalkhoff, S.; Hirsch, R. M.; Liao, L.; Barnes, K.

    2013-12-01

    Nitrogen fluxes from agricultural lands are a major concern for ecological health and water quality. Understanding how these fluxes respond to changes in agricultural practices and climatic variations is important for improving water quality in agricultural settings. In the midwestern USA, intensification of corn cropping as a result of ethanol production led to increases in N application rates in the 2000s during a period including both extreme dry and wet conditions. To examine the effect of these recent changes, a study was conducted on surface water quality in 10 major Iowa Rivers. Long term (~20 to 30 years) water quality and flow data were analyzed with Weighted Regression on Time, Discharge and Season (WRTDS), a statistical method that provides internally consistent estimates of the concentration history and reveals decadal trends that are independent of random variations of stream flow from seasonal averages. Trends of surface water quality showed constant or decreasing flow-normalized concentrations of nitrate+nitrite-N from 2000 to 2012 in all basins. To evaluate effects of annual discharge and N loading on these trends, multiple conceptual models were developed and calibrated to annual concentrations. The recent declining concentration trends can be attributed to both very high and very low discharge in the 2000's and to the long (e.g. 8-year) subsurface residence times in some basins. Dilution of surface water nitrate and depletion of stored nitrate may occur in years with very high discharge. Limited transport of N to surface water and accumulation of stored N may occur in years with very low discharge. Central Iowa basins showed the greatest reduction in concentrations, likely because extensive tile drainage results in smaller storage volumes and shorter residence times, and the glacial sediments are naturally reducing. Effects of agricultural intensification from ethanol production and other factors will likely be delayed for years or decades in

  19. A New Weighting Function for Estimating Microwave Sounding Unit Channel 4 Temperature Trends Simulated by CMIP5 Climate Models

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xuanze; ZHENG Xiaogu; YANG Chi; LUO San

    2013-01-01

    A new static microwave sounding unit (MSU) channel 4 weighting function is obtained from using Coupled Model Inter-comparison Project,Phase 5 (CMIP5) historical multimodel simulations as inputs into the fast Radiative Transfer Model for TOVS (RTTOV vl0).For the same CMIP5 model simulations,it is demonstrated that the computed MSU channel 4 brightness temperature (T4) trends in the lower stratosphere over both the globe and the tropics using the proposed weighting function are equivalent to those calculated by RTTOV,but show more cooling than those computed using the traditional UAH (University of Alabama at Huntsville) or RSS (Remote Sensing Systems in Santa Rosa,California) static weighting functions.The new static weighting function not only reduces the computational cost,but also reveals reasons why trends using a radiative transfer model are different from those using a traditional static weighting function.This study also shows that CMIP5 model simulated T4 trends using the traditional UAH or RSS static weighting functions show less cooling than satellite observations over the globe and the tropics.Although not completely removed,this difference can be reduced using the proposed weighting function to some extent,especially over the tropics.This work aims to explore the reasons for the trend differences and to see to what extent they are related to the inaccurate weighting functions.This would also help distinguish other sources for trend errors and thus better understand the climate change in the lower stratosphere.

  20. Predcition of Long term Water table Trends in Response to Groundwater Irrigation and Climate Change in an Indian Context

    Science.gov (United States)

    Thekkemeppilly Sivakumar, I.; Steenhuis, T. S.; Walter, M. F.; Ghosh, S.; Salvi, K. A.

    2015-12-01

    Intensified groundwater irrigation is a major factor that contributes to water table decline. This phenomenon has been documented in many parts of the world. This study investigates trends in water table in response to agriculture intensification to meet increasing food demand, water management practices and climate change. A shallow-aquifer model based on the extended Thornthwaite-Mather procedure is used to predict groundwater levels in response to precipitation, evapotranspiration, and groundwater pumping for irrigation. Krishna district in the state of Andhra Pradesh in southern India which has a sub-humid, monsoon climate and Calicut district of Kerala state with a wet tropical monsoon climate have been chosen as sites for this study. The effect of increasing food demand by a growing population is investigated by increasing the number of crops per year from one to three. We consider three climate scenarios and two water management practices in this study. The three climate scenarios are the ones those envisaged by the Intergovernmental Panel for Climate Change (IPCC). The two water management practices considered are the traditional flooded agriculture and the system of rice intensification method which does not use total flooding. The results show that single crop agriculture in Krishna district is sustainable for all climate scenarios and water management practices with a maximum depth to water table around 6 - 7 m at the end of dry season and the water table recovers to the surface most of the time. Increasing crop production with two or three crops per year with groundwater irrigation is unsustainable with the water table levels dropping potentially to 200 - 1000 m at the end of 21st century. We found that climate change and better irrigation water management practices affected ground water levels only minimally compared to the growing more than one crop per year. Our study leads to the conclusion that ground water irrigated rice can only be sustainable

  1. Community-level climate change vulnerability research: trends, progress, and future directions

    Science.gov (United States)

    McDowell, Graham; Ford, James; Jones, Julie

    2016-03-01

    This study systematically identifies, characterizes, and critically evaluates community-level climate change vulnerability assessments published over the last 25 years (n = 274). We find that while the field has advanced considerably in terms of conceptual framing and methodological approaches, key shortcomings remain in how vulnerability is being studied at the community-level. We argue that vulnerability research needs to more critically engage with the following: methods for evaluating future vulnerability, the relevance of vulnerability research for decision-making, interdependencies between social and ecological systems, attention to researcher / subject power dynamics, critical interpretation of key terms, and consideration of the potentially positive opportunities presented by a changing climate. Addressing these research needs is necessary for generating knowledge that supports climate-affected communities in navigating the challenges and opportunities ahead.

  2. The characteristic trends of karst springs discharges in relation to climate change (examples from the Classical Karst, SE Slovenia)

    Science.gov (United States)

    Ravbar, Natasa; Kovacic, Gregor

    2016-04-01

    Changes in the large-scale hydrological cycle induced by global warming are among the biggest actual concerns. The observed records and climate simulations are consistent in projecting changing precipitation and temperature patterns worldwide. Particularly the incidence of changed precipitation amount, intensity and variability may increase changes in hydrological regimes, and could have implications on water quantity and quality in many areas. This may affect freshwater dependant ecosystems and several socio-economic activities. Groundwater resources availability, stability of access and utilisation may further provoke difficulties for many services, such as drinking water supply, agriculture, industry, hydropower, etc. Karst aquifers are due to their specific nature (i.e. rapid infiltration rates and underground water flow, highly controlled by conduits) highly dependent on respective hydrological conditions. The goal of this study was to better understand how and to what extent impacts of the climate change may affect karst groundwater resources and to quantify the role of karst aquifers in flood attenuation and baseflow maintenance. The characteristic linear trends of mean, minimal and maximal annual discharge values of nine selected karst springs in SE Slovenia have been assessed and compared with the linear trends of annual precipitation amount and air temperature covering a 52-year period (1961 - 2013). The data have also been evaluated in respect to the individual spring's catchment characteristics (e.g. storage capacity). Obtained results and analysis reveal the impacts of climate (environmental) change on karst groundwater and call for urgent adherence of standards for karst water sources protection, monitoring and rational use in the relevant management strategies.

  3. Addressing Air, Land & Water Nitrogen Issues under Changing Climate Trends & Variability

    Science.gov (United States)

    The climate of western U.S. dairy producing states is anticipated to change significantly over the next 50 to 75 years. A multimedia modeling system based upon the “nitrogen cascade” concept has been configured to address three aspects of sustainability (environmenta...

  4. Trends in the mortality effects of hot spells in central Europe: adaptation to climate change?

    Czech Academy of Sciences Publication Activity Database

    Kyselý, Jan; Plavcová, Eva

    San Francisco: AGU, 2013. NH51B-1609. [AGU Fall Meeting 2013. 09.12.2013-13.12.2013, San Francisco] Institutional support: RVO:68378289 Keywords : climate change and variability * extreme events * health impact Subject RIV: DG - Athmosphere Sciences, Meteorology http://abstractsearch.agu.org/meetings/2013/FM/sections/NH/sessions/NH51B/abstracts/NH51B-1609.html

  5. Cenozoic sequence stratigraphy in the eastern North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Michelsen, O.; Thomsen, E.; Danielsen, M.; Heilmann-Clausen, C.; Jordt, H.; Laursen, G.V.

    1995-05-01

    The Cenozoic evolution of the epicontinental North Sea Basin is described on the basis of sequence stratigraphy, comprising analyses of seismic sections, petrophysical logs, and biostratigraphic studies of foraminifera, dinoflagellates, and calcareous nannofossils. Stratigraphic, palaeogeographic, and palaeoecological information from the Danish onshore area is integrated in the study. The deposits are subdivided into 21 sequences, which groups into seven informal major units. The sequence boundaries are identified by differences in seismic facies and by seismic onlap, toplap, and truncation features. The maximum flooding surface is placed at an internal downlap surface which correlates with high values on the gamma ray log. The source of sediments and the direction of sediment transport changed several times during the Cenozoic. Transport was mainly from the north during the Late Paleocene and Early Eocene, from the west during the Middle and Late Eocene, and from the north and northwest during the Oligocene to quaternary. The depocenters of the seven major units are generally located marginally, probably adjoining the source areas. There is only minor evidence for changes in subsidence rates in the basin. A constant rate is assumed from the Paleocene to the mid Middle Miocene. For the remaining part of the Cenozoic and increased rate is indicated. A tentative relative sea-level curve for the North Sea Basin is proposed. The overall trends of the curve are broadly comparable with the global sea-level curve of Haq et al. Discrepancies may be caused by differences in the biostratigraphic calibrations. The most pronounced Oligocene sea-level fall is dated ot the latest Oligocene. (au) (83 refs.)

  6. A fractal climate response function can explain global temperature trends of the modern era and the past millennium

    CERN Document Server

    van Hateren, J H

    2013-01-01

    A climate response function is introduced that consists of six exponential (low-pass) filters with weights depending as a power law on their e-folding times. The response of this function to the combined forcings of solar irradiance, greenhouse gases, and SO2-related aerosols is fitted simultaneously to reconstructed temperatures of the past millennium, the response to solar cycles, the response to the 1991 Pinatubo volcanic eruption, and the modern 1850-2010 temperature trend. The quite adequate fit produces a climate response function with an equilibrium response to doubling of CO2 concentration of 2.0 \\pm 0.3 ^{\\circ}C (mean \\pm standard error), of which about 50% is realized with e-folding times of 0.5 and 2 years, about 30% with e-folding times of 8 and 32 years, and about 20% with e-folding times of 128 and 512 years. The transient climate response (response after 70 years of 1% yearly rise of CO2 concentration) is 1.5 \\pm 0.2 ^{\\circ}C. The temperature rise from 1820-1950 can be attributed for about 70...

  7. Differentiating between Land Use and Climate-driven Change using Long-term Vegetation Index Trends adjusted for Precipitation on the Mongolian Plateau

    Science.gov (United States)

    John, R.; Chen, J.; Kim, Y.; Yang, Z.; Xiao, J.; Shao, C.; Batkhishig, O.

    2014-12-01

    The Mongolian plateau is undergoing consistent warming in addition to an increase in extreme climatic events. Land cover/land use change has accelerated over the past three decades, owing to post liberalization socio-economic changes in Inner Mongolia, China (IM) Mongolia (MG) which have different political systems. Extensive anthropomorphic modifications of ecosystems have the ability to alter the structure and function of ecosystems and ecological processes such as the carbon and water cycle and it is therefore important to differentiate between such changes from climate-driven changes. This study identified climate-driven and human-induced changes in vegetation cover on the Mongolian plateau across desert, grassland and forest biomes as well as administrative divisions. We applied non-parametric trend tests on time series of vegetation index datasets that include MODIS EVI, Vegetation Index and Phenology (VIP) EVI2, and GIMMS 3g as well as precipitation and temperature obtained from TRMM and MERRA reanalysis datasets. We then correlated the VI trends with the climate drivers to determine and isolate primary climate drivers. VI residuals obtained from the regression of composites of peak season maximum VI and JJA monthly accumulated rainfall were analyzed for detection of trends in vegetation greenness not explained by rainfall dynamics over different time periods (2000-2012, and 1981 to 2010). In addition, we obtained trends in socioeconomic variables like total livestock and population density which were closely correlated with VI residual trends adjusted for rainfall. Some administrative subdivisions in IM and MG showed a decreasing trend in residuals that could be attributed to anthropogenic activity such as grazing, or urbanization, while other subdivisions showed an increasing trend in residuals increasing trend in residuals suggest that vegetation cover has improved and perhaps be attributed to restoration and conservation efforts.

  8. Modelling trends in climatic time series using the state space approach

    Science.gov (United States)

    Laine, Marko; Kyrölä, Erkki

    2014-05-01

    A typical feature of an atmospheric time series is that they are not stationary but exhibit both slowly varying and abrupt changes in the distributional properties. These are caused by external forcing such as changes in the solar activity or volcanic eruptions. Further, the data sampling is often nonuniform, there are data gaps, and the uncertainty of the observations can vary. When observations are combined from various sources there will be instrument and retrieval method related biases. The differences in sampling lead to uncertainties, also. Dynamic regression with state space representation of the underlying processes provides flexible tools for these challenges in the analysis. By explicitly allowing for variability in the regression coefficients we let the system properties change in time. This change in time can be modelled and estimated, also. Furthermore, the use of unobservable state variables allows modelling of the processes that are driving the observed variability, such as seasonality or external forcing, and we can explicitly allow for some modelling error. The state space approach provides a well-defined hierarchical statistical model for assessing trends defined as long term background changes in the time series. The modelling assumptions can be evaluated and the method provides realistic uncertainty estimates for the model based statements on the quantities of interest. We show that a linear dynamic model (DLM) provides very flexible tool for trend and change point analysis in time series. Given the structural parameters of the model, the Kalman filter and Kalman smoother formulas can be used to estimate the model states. Further, we provide an efficient way to account for the structural parameter uncertainty by using adaptive Markov chain Monte Carlo (MCMC) algorithm. Then, the trend related statistics can be estimated by simulating realizations of the estimated processes with fully quantified uncertainties. This presentation will provide a

  9. Dynamic topography and the Cenozoic carbonate compensation depth

    Science.gov (United States)

    Campbell, S. M.; Moucha, R.; Raymo, M. E.; Derry, L. A.

    2015-12-01

    The carbonate compensation depth (CCD), the ocean depth at which the calcium carbonate accumulation rate goes to zero, can provide valuable insight into climatic and weathering conditions over the Cenozoic. The paleoposition of the CCD can be inferred from sediment core data. As the carbonate accumulation rate decreases linearly with depth between the lysocline and CCD, the CCD can be calculated using a linear regression on multiple sediment cores with known carbonate accumulation rates and paleodepths. It is therefore vital to have well-constrained estimates of paleodepths. Paleodepths are typically calculated using models of thermal subsidence and sediment loading and compaction. However, viscous convection-related stresses in the mantle can warp the ocean floor by hundreds of meters over broad regions and can also vary significantly over millions of years. This contribution to paleobathymetry, termed dynamic topography, can be calculated by modeling mantle flow backwards in time. Herein, we demonstrate the effect dynamic topography has on the inference of the late Cenozoic CCD with an example from the equatorial Pacific, considering sites from IODP Expeditions 320/321. The equatorial Pacific, given its large size and high productivity, is closely tied to the global carbon cycle. Accordingly, long-term changes in the equatorial Pacific CCD can be considered to reflect global changes in weathering fluxes and the carbon cycle, in addition to more regional changes in productivity and thermohaline circulation. We find that, when the dynamic topography contribution to bathymetry is accounted for, the equatorial Pacific CCD is calculated to be appreciably shallower at 30 Ma than previous estimates would suggest, implying a greater deepening of the Pacific CCD over the late Cenozoic.

  10. Recent climate trends and multisecular climate variability: temperature and precipitation during the cold season (October-March) in the Ebro Basin (NE of Spain) betrween 1500 and 2008

    Science.gov (United States)

    Saz-Sanchez, M.-A.; Cuadrat-Prats, J.-M.

    2009-09-01

    One of the goals of Paleoclimatology is to assess the importance and the exceptional nature of recent climate trends related to the anthropogenic climate change. Instrumental data enable the analysis of last century's climate, but do not give any information on previous periods' precipitation and temperature, during which there was no anthropic intervention on the climate system. Dendroclimatology is one of the paleoclimatic reconstruction sources giving best results when it comes to reconstructing the climate of the time before instruments could be used. This work presents the reconstructed series of precipitation and temperature of the cold season (October-March) In the central sector of the Ebro Valley (NE of Spain). The chronologies used for the reconstruction come on the one hand from the International Tree-Ring Data Bank (ITRDB) and on the other hand from the dendrochronological information bank created in the northern half of the Iberian Peninsula within the framework of the Spanish Interministerial Commission for Science and Technology (CICYT) CLI96-1862 project. The climate data used for chronology calibration and the reconstruction of the temperature and precipitation values are those of the instrumental observatory number 9910 (Pallaruelo) belonging to the Spanish State Meteorological Agency (Agencia Estatal de Meteorología or AEMET), located in the central sector of the Ebro Valley. The reconstruction obtained covers the 1500-1990 period. In order to extend the series up to 2008, instrumental information has been used. Thanks to data from a set of AEMET instrumental observatories close to the one used for chronology calibration, a regional series of temperatures as well as a precipitation one were generated. The series reconstructed through dendroclimatic methods and the regional series do not show statistically significant differences in their mean and variance values. R values between both series exceed 0.85. Taking these statistical characteristics

  11. TRENDS IN ATMOPSHERIC CLIMATE PARAMETERS MEASURED AT SRS 1964-2013

    Energy Technology Data Exchange (ETDEWEB)

    Weinbeck, S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-04-20

    Meteorological data collected at SRS since the mid-1960’s have been analyzed for trends in minimum and maximum temperature, heating and cooling degree days, precipitation and relative humidity. The trends in meteorological data collected have been relatively small compared to the interannual variability that is observed. The observed increases, while small, appear to be real (statistically significant). Overnight low temperatures (3.1°F) have increased over twice as fast as the increases in daytime highs (1.4°F). Similarly, there are statistically significant increases in the number of cooling degree days as well. There has been a similar decrease in the number of HDD and freezing days, consistent with the overall increase in overnight low temperatures.

  12. Air pollution and climate response to aerosol direct radiative effects: A modeling study of decadal trends across the northern hemisphere

    Science.gov (United States)

    Xing, Jia; Mathur, Rohit; Pleim, Jonathan; Hogrefe, Christian; Gan, Chuen-Meei; Wong, David C.; Wei, Chao; Wang, Jiandong

    2015-12-01

    Decadal hemispheric Weather Research and Forecast-Community Multiscale Air Quality simulations from 1990 to 2010 were conducted to examine the meteorology and air quality responses to the aerosol direct radiative effects. The model's performance for the simulation of hourly surface temperature, relative humidity, wind speed, and direction was evaluated through comparison with observations from NOAA's National Climatic Data Center Integrated Surface Data. The inclusion of aerosol direct radiative effects improves the model's ability to reproduce the trend in daytime temperature range which over the past two decades was increasing in eastern China but decreasing in eastern U.S. and Europe. Trends and spatial and diurnal variations of the surface-level gaseous and particle concentrations to the aerosol direct effect were analyzed. The inclusion of aerosol direct radiative effects was found to increase the surface-level concentrations of SO2, NO2, O3, SO42-, NO3-, and particulate matter 2.5 in eastern China, eastern U.S., and Europe by 1.5-2.1%, 1-1.5%, 0.1-0.3%, 1.6-2.3%, 3.5-10.0%, and 2.2-3.2%, respectively, on average over the entire 21 year period. However, greater impacts are noted during polluted days with increases of 7.6-10.6%, 6.2-6.7%, 2.0-3.0%, 7.8-9.5%, 11.1-18.6%, and 7.2-10.1%, respectively. Due to the aerosol direct radiative effects, stabilizing of the atmosphere associated with reduced planetary boundary layer height and ventilation leads to an enhancement of pollution. Consequently, the continual increase of aerosol optical depth (AOD) in eastern China leads to an increasing trend in the air quality feedback which exacerbates air pollution, while emission reductions in eastern U.S. and Europe result in a declining trend in both AODs and feedback which make the air pollution control strategies more effective.

  13. Trends in climatic variables and future reference evapotranspiration in Duero Valley (Spain)

    OpenAIRE

    R. Moratiel; Snyder, R. L.; Durán, J. M.; Tarquis, A. M.

    2011-01-01

    The impact of climate change and its relation with evapotranspiration was evaluated in the Duero River Basin (Spain). The study shows possible future situations 50 yr from now from the reference evapotranspiration (ETo). The maximum temperature (Tmax), minimum temperature (Tmin), dew point (Td), wind speed (U) and net radiation...

  14. The Impact of Climate Trends on a Tick Affecting Public Health: A Retrospective Modeling Approach for Hyalomma marginatum (Ixodidae.

    Directory of Open Access Journals (Sweden)

    Agustín Estrada-Peña

    Full Text Available The impact of climate trends during the period 1901-2009 on the life cycle of Hyalomma marginatum in Europe was modeled to assess changes in the physiological processes of this threat to public health. Monthly records of temperature and water vapour at a resolution of 0.5° and equations describing the life cycle processes of the tick were used. The climate in the target region affected the rates of the life cycle processes of H. marginatum: development rates increased, mortality rates in molting stages decreased, and the survival rates of questing ticks decreased in wide territories of the Mediterranean basin. The modeling framework indicated the existence of critical areas in the Balkans, central Europe, and the western coast of France, where the physiological processes of the tick improved to extents that are consistent with the persistence of populations if introduced. A spatially explicit risk assessment was performed to detect candidate areas where active surveys should be performed to monitor changes in tick density or persistence after a hypothetical introduction. We detected areas where the critical abiotic (climate and biotic (host density factors overlap, including most of the Iberian peninsula, the Mediterranean coast of France, eastern Turkey, and portions of the western Black Sea region. Wild ungulate densities are unavailable for large regions of the territory, a factor that might affect the outcome of the study. The risk of successfully establishing H. marginatum populations at northern latitudes of its current colonization range seems to be still low, even if the climate has improved the performance of the tick in these areas.

  15. Getting caught with our plants down: the risks of a global crop yield slowdown from climate trends in the next two decades

    International Nuclear Information System (INIS)

    In many discussions of climate change impacts in agriculture, the large magnitudes of expected impacts toward the end of the century are used to emphasize that most of the risks are to future generations. However, this perspective misses the important fact that demand growth for food is expected to be much slower after 2050 than before it, and that the next two decades represent the bulk of growth before 2050. Thus, impacts of smaller magnitude in the near-term can be as or more consequential for food prices or food security as larger magnitude impacts in the future. Here we estimate the risks that climate trends over the next 10 or 20 years could have large impacts on global yields of wheat and maize, with a focus on scenarios that would cut the expected rates of yield gains in half. We find that because of global warming, the chance of climate trends over a 20 year period causing a 10% yield loss has increased from a less than 1 in 200 chance arising from internal climate variability alone, to a 1 in 10 chance for maize and 1 in 20 chance for wheat. Estimated risks for maize are higher because of a greater geographic concentration than wheat, as well as a slightly more negative aggregate temperature sensitivity. Global warming has also greatly increased the chance of climate trends large enough to halve yield trends over a 10 year period, with a roughly 1 in 4 chance for maize and 1 in 6 chance for wheat. Estimated risks are slightly larger when using climate projections from a large ensemble of a single climate model that more fully explores internal climate variability, than a multi-model ensemble that more fully explores model uncertainty. Although scenarios of climate impacts large enough to halve yield growth rates are still fairly unlikely, they may warrant consideration by institutions potentially affected by associated changes in international food prices. (paper)

  16. Getting caught with our plants down: the risks of a global crop yield slowdown from climate trends in the next two decades

    Science.gov (United States)

    Lobell, David B.; Tebaldi, Claudia

    2014-07-01

    In many discussions of climate change impacts in agriculture, the large magnitudes of expected impacts toward the end of the century are used to emphasize that most of the risks are to future generations. However, this perspective misses the important fact that demand growth for food is expected to be much slower after 2050 than before it, and that the next two decades represent the bulk of growth before 2050. Thus, impacts of smaller magnitude in the near-term can be as or more consequential for food prices or food security as larger magnitude impacts in the future. Here we estimate the risks that climate trends over the next 10 or 20 years could have large impacts on global yields of wheat and maize, with a focus on scenarios that would cut the expected rates of yield gains in half. We find that because of global warming, the chance of climate trends over a 20 year period causing a 10% yield loss has increased from a less than 1 in 200 chance arising from internal climate variability alone, to a 1 in 10 chance for maize and 1 in 20 chance for wheat. Estimated risks for maize are higher because of a greater geographic concentration than wheat, as well as a slightly more negative aggregate temperature sensitivity. Global warming has also greatly increased the chance of climate trends large enough to halve yield trends over a 10 year period, with a roughly 1 in 4 chance for maize and 1 in 6 chance for wheat. Estimated risks are slightly larger when using climate projections from a large ensemble of a single climate model that more fully explores internal climate variability, than a multi-model ensemble that more fully explores model uncertainty. Although scenarios of climate impacts large enough to halve yield growth rates are still fairly unlikely, they may warrant consideration by institutions potentially affected by associated changes in international food prices.

  17. Climate, runoff and landuse trends in the Owo River Catchment in Nigeria

    Science.gov (United States)

    Adegun, O.; Odunuga, S.; Ajayi, O. S.

    2015-06-01

    The Owo River is an important surface water source in Lagos particularly to the western section. It is the source of direct water intake for water supply by Lagos State Water Corporation to Amuwo-Odofin, Ojo and parts of Badagry Local Government Areas. This paper examines the complex interactions and feedbacks between many variables and processes within that catchment and analyses the future ability of this semi-urban watershed in sustaining water supply in the face of cumulative environmental change. Stationarity analysis on rainfall, change detection analysis and morphometry analysis were combined to analyse the non-stationarity of Owo River catchment. On rainfall trend analysis, since the correlation coefficient (0.38) with test statistic of 2.17 did not satisfy the test condition we concluded that there is trend and that rainfall in the watershed is not stationary. The dominant land use impacting on the bio-geochemical fluxes is built up area (including structures and paved surfaces) which grew from about 142.92 km2 (12.20%) in 1984 to 367.22 km2 (31.36%) in 2013 recording gain of 224.3 km2 at average growth rate of 7.73 km2 per annum. Total length of streams within the catchment reduced from 622.24 km in 1964 to 556 km in 2010, while stream density reduced from 0.53 in 1964 to 0.47 in 2010 an indication of shrinking hydrological network. The observed trends in both natural and anthropogenic processes indicated non-stationarity of the hydrological fluxes within the Catchment and if this continues, the urban ecosystem services of water supply will be compromised.

  18. Geomorphology and regional stratigraphic model of Cenozoic deposits from "Continental to Marine" of Western Peninsular Malaysia and Strait of Malacca.

    Science.gov (United States)

    Menier, David; Mansor, Yazid; Sautter, Benjamin; Pubellier, Manuel; Estournes, Guilhem; Meng Choong, Chee; Ghosh Deva, Prasad; Proust, Jean-Noel; Goubert, Evelyne

    2014-05-01

    Coastal basins have been greatly influenced worldwide by their geological heritage (lithology, structural control) and eustatic sea-level fluctuations. Along the western side of Peninsular Malaysia, both the structures of the tertiary-quaternary basement and the geomorphology are poorly known. The coast is characterized landward by an absence of tertiary deposits on the alluvial and coastal plains and seaward by numerous deeply incised valleys although the incision potential is low. Offshore, in the Strait of Malacca, the thickness of sediments increases drastically, particularly at the apex of some N-S elongated basins (> 2 Km), and in the central part of the Strait of Malacca. Onshore, the geomorphology of the Western Peninsular Malaysia is controlled mostly by climatic effects on an old (Indosinian) orogen affected by transtensional brittle tectonics during the Tertiary. We investigate the effects of Tertiary extension and associated vertical motions on the Cenozoic geomorphology and stratigraphy. The study is based on a combined morphobathymetric approach of based on GEBCO data, supported by low and recent high resolution offshore seismic data, and DTM data from ASTER and SRTM. The main results are the followings: (1) the structural control appears to be responsible of the positioning and preservation of the Tertiary deposits; while the Quaternary (marine) deposits thinner, drowned the western Malaysia Peninsular coast, independently of the geomorphological and structural context; (2) The offshore Tertiary deposits seem disconnected from the modern drainage network, suggesting probable uplift during the late Tertiary period, which reactivated NW-SE trending faults and fractures; (3) The orientation, the shape and the depth of the ancient and modern incised valleys (Perak, Kerian , Kinta rivers) are controlled by the structural context and lithological contrast; (4) Finally, from a landward to a seaward directions, the Cenozoic deposits seems to have transited

  19. Historical Trends in Lake and River Ice Cover in Norway : signs of a changing climate

    OpenAIRE

    2013-01-01

    Recent studies have shown that the duration of seasonal ice cover on lakes and rivers over the Northern Hemisphere has declined over the 19th and 20th Centuries, mainly as a consequence of rising temperatures. However, lake and river ice trends have not been well documented in Norway. Quality control and homogeneity testing were performed on ice cover data from 48 Norwegian lake and river sites with long records. A total of 142 individual records of ice phenology (freeze-up, break-up and ice ...

  20. History of oceanic front development in the New Zealand sector of the Southern Ocean during the Cenozoic: a synthesis

    International Nuclear Information System (INIS)

    subantarctic belt. In the Early-early Middle Miocene (25-15 Ma), warm subtropical waters expanded southwards into the northern NZSSO, possibly associated with reduced ice volume on East Antarctica but particularly with restriction of the Indonesian gateway and redirection of intensified warm surface flows southwards into the Tasman Sea, as well as complete opening of the Drake gateway by 23 Ma allowing more complete decoupling of cool circum-Antarctic flow from the subtropical waters. During the late Middle-Late Miocene (15-5 Ma), both the STF and SAF proper were established in their present relative positions across and about the Campbell Plateau, respectively, accompanying renewed ice buildup on East Antarctica and formation of a permanent ice sheet on West Antarctica, as well as generally more expansive and intensified circum-Antarctic flow. The ultimate control on the history of oceanic front development in the NZSSO has been plate tectonics through its influence on the paleogeographic changes of the Australian-New Zealand-Antarctic continents and their intervening oceanic basins, the timing of opening and closing of critical seaways, the potential for submarine ridges and plateaus to exert some bathymetric control on the location of fronts, and the evolving ice budget on the Antarctic continent. The broad trends of the Cenozoic climate curve for New Zealand deduced from fossil evidence in the uplifted marine sedimentary record correspond well to the principal paleoceanographic events controlling the evolution and migration of the oceanic fronts in the NZSSO. (author). 104 refs., 9 figs., 3 tabs

  1. The Trends of Climate Change Convention and the Countermeasures of Korea after Marrakesh Agreement

    Energy Technology Data Exchange (ETDEWEB)

    Woo, S.H. [Korea Energy Management Corporation, Yongin (Korea)

    2002-01-01

    The year of 2001 produced a reversal drama in Climate Change Convention with a dramatic plot. The Forth Session of Conference of the Parties, which was held in Argentina having severe economic difficulty now in the year after a historic Kyoto Protocol, just agreed to a two-year schedule, called as a Buenos Aires Action Plan. Conference of the Parties (COP) at its resumed sixth session in Bonn, Germany was the turning point to decide whether Kyoto Protocol can survive, a different protocol has to start again for a few years, or the already effectuated Climate Change Convention ends as a kind of an international happening. Finally, COP concluded Bonn Agreement, a dramatic settlement except USA, and the Agreement was succeeded to Marrakesh Agreement, which is an actual international agreement even though it goes far from historic Kyoto principle and has a doubt of practical results. Afterward, each country will proceed the ratifying process with Marrakesh Agreement -implementing measures of Kyoto Protocol. If advanced countries including EU, leading the ratification, perform the intended plan, the effectuation of Kyoto Protocol will be declared, regardless of types, in Rio+10 World Summit on Environment, which will be hold in Johannesburg, the Republic of South Africa, in September 2002.

  2. Global pattern of trends in streamflow and water availability in a changing climate.

    Science.gov (United States)

    Milly, P C D; Dunne, K A; Vecchia, A V

    2005-11-17

    Water availability on the continents is important for human health, economic activity, ecosystem function and geophysical processes. Because the saturation vapour pressure of water in air is highly sensitive to temperature, perturbations in the global water cycle are expected to accompany climate warming. Regional patterns of warming-induced changes in surface hydroclimate are complex and less certain than those in temperature, however, with both regional increases and decreases expected in precipitation and runoff. Here we show that an ensemble of 12 climate models exhibits qualitative and statistically significant skill in simulating observed regional patterns of twentieth-century multidecadal changes in streamflow. These models project 10-40% increases in runoff in eastern equatorial Africa, the La Plata basin and high-latitude North America and Eurasia, and 10-30% decreases in runoff in southern Africa, southern Europe, the Middle East and mid-latitude western North America by the year 2050. Such changes in sustainable water availability would have considerable regional-scale consequences for economies as well as ecosystems. PMID:16292308

  3. A decadal trend of juvenile European sea bass (Dicentrarchus labrax, L. responses to climate patterns in the Mondego estuary, Portugal

    Directory of Open Access Journals (Sweden)

    Eduardo Granja Bento

    2015-11-01

    Full Text Available Estuarine systems support the life cycle stages of commercially important marine fish and are influenced by large and local-scale climatic patterns. Also, extreme events triggered by climate changes may influence the functioning of nursery grounds and recruitment for several fish species. In this study, performed in the Mondego estuary, Portugal, we used an 11-year database (2003-2013 for analyzing the variability in the population of a marine juvenile migrant fish, the European sea bass Dicentrarchus labrax, regarding changes in abundance, population structure, growth rates and secondary production and annual day of peak abundance. Higher densities and production occurred at the beginning of the study, but no differences in 0-group growth could be observed. In order to detect change points in both biological and climatic data, the cumulative sum (CUSUM of the deviations from the mean for the 2003-2013 period were determined for each parameter. The relationship between large- and local-scale drivers and 0-group abundance, secondary production and day of peak abundance were evaluated using a Pearson correlation analysis of CUSUM of biological and environmental data, considering the correspondent yearly values and with a time-lag of 1 year. The North Atlantic Oscillation (NAO index, sea surface temperature (SST and their respective winter values were tested as large-scale factors, while river runoff, salinity and water temperature were considered as local climate patterns. River runoff was the significant factor explaining D. labrax 0-group abundances and the NAO and water temperature were also significant predictors considering the 1-year lag. Regarding D. labrax 0-group secondary production, salinity and water temperature were the significant predictors. The NAO with 1-year lag was also negatively correlated with the day of peak abundance. The observed variability regarding yearly trends in abundance of juvenile fish was mostly linked to local

  4. Herbarium specimens reveal the footprint of climate change on flowering trends across north-central North America.

    Science.gov (United States)

    Calinger, Kellen M; Queenborough, Simon; Curtis, Peter S

    2013-08-01

    Shifting flowering phenology with rising temperatures is occurring worldwide, but the rarity of co-occurring long-term observational and temperature records has hindered the evaluation of phenological responsiveness in many species and across large spatial scales. We used herbarium specimens combined with historic temperature data to examine the impact of climate change on flowering trends in 141 species collected across 116,000 km(2) in north-central North America. On average, date of maximum flowering advanced 2.4 days °C(-1), although species-specific responses varied from - 13.5 to + 7.3 days °C(-1). Plant functional types exhibited distinct patterns of phenological responsiveness with significant differences between native and introduced species, among flowering seasons, and between wind- and biotically pollinated species. This study is the first to assess large-scale patterns of phenological responsiveness with broad species representation and is an important step towards understanding current and future impacts of climate change on species performance and biodiversity. PMID:23786499

  5. Major-elements trends in cenozoic volcanites of Hungary

    OpenAIRE

    Martín Fernández, Josep Antoni; Barceló i Vidal, Carles; Pawlowsky-Glahn, Vera; Kovács, L.Ó.; Kovács, G.P.

    2003-01-01

    Hungary lies entirely within the Carpatho-Pannonian Region (CPR), a dominant tectonic unit of eastern Central Europe. The CPR consists of the Pannonian Basin system, and the arc of the Carpathian Mountains surrounding the lowlands in the north, east, and southeast. In the west, the CPR is bounded by the Eastern Alps, whereas in the south, by the Dinaridic belt. (...) Geologische Vereinigung; Universitat de Barcelona, Equip de Recerca Arqueomètrica; Institut d’Estadística de Catalunya; Inte...

  6. Dust interannual variability and trend in Central Asia from 2000 to 2014 and their climatic linkages

    Science.gov (United States)

    Xi, Xin; Sokolik, Irina N.

    2015-12-01

    We present a comprehensive analysis of the interannual variability and trend of dust aerosol in Central Asia (37°-55°N, 50°-80°E) from 2000 to 2014, based on a set of dust emission simulations using the WRF-Chem-DuMo modeling system, observations of dust frequency derived from surface station synoptic weather records, and dust optical depth (DOD) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) and Sea-viewing Wide Field-of-view Sensor (SeaWiFS) aerosol optical depth (AOD) products. Model simulations reveal that the soil grain size distribution has little impact on the interannual variability of dust fluxes but strongly affects their magnitude. The two physically based dust schemes based on Marticorena and Bergametti (1995) (MB) and Shao et al. (1996) (Shao) produce large differences in the dust flux magnitude and spatiotemporal distributions, largely due to different sensitivities of the threshold friction velocity to vegetation-induced surface roughness. By using a fixed threshold velocity, the dust scheme of Tegen and Fung (1995) (TF) relies on the dynamic dust source function to capture the dust variability associated with vegetation changes. Through a correlation analysis, the simulated dust fluxes show good consistency with the observed dust frequency, whereas only the Shao and TF dust fluxes are consistent with the MODIS Collection 5.1 and SeaWiFS DOD. The dust fluxes, dust frequency, and DOD (except MODIS Collection 6) are highly correlated with the frequency of strong surface winds but show different sensitivities to drought and soil erodibility factors (i.e., precipitation, soil moisture, and vegetation) which are influenced by El Niño-Southern Oscillation (ENSO). In general, La Niña years are associated with reduced precipitation, drier soils, less vegetation, and, consequently, more severe drought and enhanced dust activity in Central Asia. The averaged dust flux of the MB and Shao experiments shows a significant negative trend

  7. Streamflow in the Winnipeg River basin, Canada: Trends, extremes and climate linkages

    Science.gov (United States)

    St. George, Scott

    2007-01-01

    SummaryThis study uses a network of long-term discharge gauges to examine how river flow in the Winnipeg River basin, Canada has behaved during the last one hundred years. The Winnipeg River influences the production of over 4600 MW of hydroelectricity, and is the most important component of the hydrological system used to generate power in Manitoba. Extreme low annual flows are caused by severe reductions in runoff from spring snowmelt, and follow dry weather during the previous summer and autumn over much of the basin. These conditions are associated with enhanced meridional flow across western Canada, and geopotential height anomalies during the previous autumn and winter that are very similar to the positive phase of the Pacific/North American (PNA) pattern. The winter PNA index appears to be an important control on streamflow in the Winnipeg River at both interannual and decadal time-scales, but may be modulated by conditions in the North Atlantic sector. Mean annual flows have increased by 58% since 1924, primarily because of large increases in winter discharge. Because similar trends are observed for both regulated and unregulated rivers, these increases are not artefacts caused by direct anthropogenic interference in the hydrological system. Increasing summer and autumn precipitation is the most probable cause of the changes in streamflow. The observed trends toward higher flows, combined with recent model projections, suggest that the potential threats to water supply faced by the Canadian Prairie provinces over the next few decades will not include decreasing streamflow in the Winnipeg River basin.

  8. Long-Term Trend and Abrupt Change for Major Climate Variables in the Upper Yellow River Basin

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    On the basis of the mean air temperature, precipitation, sunshine duration, and pan evaporation from 23 meteorological stations in the upper Yellow River Basin from 1960 to 2001, the feasibility of using hypothesis test techniques to detect the long-term trend for major climate variables has been investigated.Parametric tests are limited by the assumptions such as the normality and constant variance of the error terms. Nonparametric tests have not these additional assumptions and are better adapted to the trend test for hydro-meteorological time series. The possible trends of annual and monthly climatic time series are detected by using a non-parametric method and the abrupt changes have been examined in terms of 5-yr moving averaged seasonal and annual series by using moving T-test (MTT) method, Yamamoto method,and Mann-Kendall method. The results show that the annual mean temperature has increased by 0.8℃ in the upper Yellow River Basin during the past 42 years. The warmest center was located in the northern part of the basin. The nonlinear tendency for annual precipitation was negative during the same period.The declining center for annual precipitation was located in the eastern part and the center of the basin.The variation of annual precipitation in the upper Yellow River Basin during the past 42 years exhibited an increasing tendency from 1972 to 1989 and a decreasing tendency from 1990 to 2001. The nonlinear tendencies for annual sunshine duration and pan evaporation were also negative. They have decreased by 125.6 h and 161.3 mm during the past 42 years, respectively. The test for abrupt changes by using MTT method shows that an abrupt warming occurred in the late 1980s. An abrupt change of the annual mean precipitation occurred in the middle 1980s and an abrupt change of the mean sunshine duration took place in the early 1980s. For the annual mean pan evaporation, two abrupt changes took place in the 1980s and the early 1990s. The test results of the

  9. DIVERSITY VARIATIONS OF THE LATE CENOZOIC MAMMALS IN THE LINXIA BASIN AND THEIR RESPONSE TO THE CLIMATIC AND ENVIRONMENTAL BACKGROUNDS%临夏盆地晚新生代哺乳动物的多样性变化及其对气候环境背景的响应

    Institute of Scientific and Technical Information of China (English)

    邓涛

    2011-01-01

    The Late Cenozoic deposits of the Linxia Basin in Gansu, China are relatively thick, bearing abundant mammalian fossils of different periods from the Late Oligocene to the Early Pleistocene. Until now, 172 species in 42 families of 10 orders have been found,all of which are extinct forms at the specific level and only a small number of genera have extant species. These fossils are important materials to study the evolution of mammalian faunas and their relationship with climatic and environmental backgrounds. The diversity and morphology of mammals are tightly related to climatic and environmental factors, and especially sensitive to changes of temperature, humidity and elevation. Interpretations to climatic and environmental changes reflect the evolution of mammals. Specific diversities, new records, and vanished species in the sedimentary sequence of the Linxia Basin are counted for each Chinese land mammal age. The diversity variations of mammals in the Linxia Basin were very noticeable throughout the Late Cenozoic,which are divided into different stages; the Middle Miocene,Late Miocene and Early Pleistocene have the highest diversities, the Late Oligocene and Early Miocene have the lowest, and the Pliocene has the moderate. The climatic and environmental variations of the Linxia Basin in different ages, which are judged from mammalian diversities, are highly consistent with other independent evidence, such as the result of the cenogram analysis, and closely relevant to the uplift of the Tibetan Plateau.%甘肃临夏盆地的晚新生代沉积物厚度巨大,其中富含从晚渐新世到早更新世各个时代的哺乳动物化石,目前已知包括10目42科131属172种,在种级水平上全部是绝灭类型,仅少数属有现生代表.这些化石是研究哺乳动物群演化及其与气候环境背景关系的重要材料.哺乳动物的多样性和形态特征与气候环境因素密切相关,对温度、湿度和海拔高度的变化尤其敏感.依据

  10. The effects of climate change on fungal diversity patterns in the UK and Greece: Contrasting trends and ecological interpretations

    Science.gov (United States)

    Damialis, A.; Gange, A. C.; Mohammad, A. B.; Halley, J. M.

    2013-05-01

    It is well known that climate change has been affecting the ecology of living organisms. However, very little research has been done concerning alterations in fungal ecology. The changes in climate are expected to have an impact on fungal biodiversity patterns. Such changes in turn might have implications for public health since the spores of certain fungal taxa (e.g. Alternaria, Cladosporium) cause respiratory problems in sensitised individuals, with symptoms manifested even as acute respiratory failure. The objectives of this study were: a) to perform a comprehensive analysis of trends in long-term time series of fungal fruiting and sporulation variables for a wide range of fungal taxa, b) to investigate the response of fungal abundance and diversity to environmental variability. Data from two different geoclimatic areas were used: a) England, UK from more than 350 fungal species belonging to 10 different functional groups and with phenological records of fungal fruiting (start, end and duration) since 1950, b) Thessaloniki, Greece for 14 airborne fungal types with quantitative records (total annual concentration) and phenological records (start, peak, end, duration) of the atmospheric spore season since 1987. In parallel, various meteorological factors were examined in both areas in order to elucidate the relationship between climate and fungal diversity patterns. Long-term trends were found in most cases: these were particularly pronounced in the UK, where more than 300 species (~82%) displayed trends. Of these, ~77% were towards an earlier beginning and ~81% towards a later ending of the fruiting season; overall, an extension of the fruiting season seems to occur in more than 200 species. On a per-functional-group basis, except for manure, soil and mycorrhizal deciduous fungal species, all the other (137 species) exhibited earlier first fruiting dates and extended seasons. On the other hand, in Greece, although a tendency was observed towards lower yearly

  11. On the ability of statistical wind-wave models to capture the variability and long-term trends of the North Atlantic winter wave climate

    OpenAIRE

    Martínez-Asensio, Adrián; Marcos, Marta; Tsimplis, Michael N.; Jordà, Gabriel; Feng, Xiangbo; Gomis, Damià

    2016-01-01

    A dynamical wind-wave climate simulation covering the North Atlantic Ocean and spanning the whole 21st century under the A1B scenario has been compared with a set of statistical projections using atmospheric variables or large scale climate indices as predictors. As a first step, the performance of all statistical models has been evaluated for the present-day climate; namely they have been compared with a dynamical wind-wave hindcast in terms of winter Significant Wave Height (SWH) trends and...

  12. Extreme Heat Wave over European Russia in Summer 2010: Anomaly or a Manifestation of Climatic Trend?

    Science.gov (United States)

    Razuvaev, V.; Groisman, P. Y.; Bulygina, O.; Borzenkova, I.

    2010-12-01

    Extraordinary temperature anomalies over European Russia (ER) in summer 2010 raised a legitimate question in the title of this presentation. A 60-days-long hot anticyclonic weather system with daily temperature anomalies as high as +10K and no or negligible amount of rainfall first decimated crops in the forest-steppe zone of ER, gradually dried wetlands in the forest zone and, finally, caused numerous natural and anthropogenic fires that at the time of this abstract preparation have not yet been extinguished. The extreme heat, lack of precipitation, and forest fires have caused hundreds of deaths and multimillion dollars in property losses. Indirect losses of lives due to this weather anomaly, with the ensuing fires and related air pollution, as well as the absence of air conditioning in apartments has yet to be estimated. The center of European Russia was well covered by meteorological observations for the past 130 years. These data, historical weather records (yearbooks or "letopisi" , which were carried on in the major Russian monasteries), and finally, dendroclimatological information, all show that this summer temperature anomaly was well above all known extremes in the past 1000 years. Like ocean waves and ocean tides, weather and climate variability go together strengthening (or mitigating) each other. We shall show the precursors of the current outbreak using principally the most accurate meteorological records of the past century updated to 2009 (at the Session, the 2010 data will also be presented). While a careful analyses of these records and thoughtful analyses of recent similar temperature outbreaks in Western Europe could not prevent the occurrence of this disaster, the lessons learned from these analyses (a) would warn about its increasing probability and (b) mitigation and adaptation measures could well be made to reduce its negative consequences. Among our arguments are: (1)There is a century-long tendency of reduction of equator minus pole

  13. Abrupt climate change and extinction events

    Science.gov (United States)

    Crowley, Thomas J.

    1988-01-01

    There is a growing body of theoretical and empirical support for the concept of instabilities in the climate system, and indications that abrupt climate change may in some cases contribute to abrupt extinctions. Theoretical indications of instabilities can be found in a broad spectrum of climate models (energy balance models, a thermohaline model of deep-water circulation, atmospheric general circulation models, and coupled ocean-atmosphere models). Abrupt transitions can be of several types and affect the environment in different ways. There is increasing evidence for abrupt climate change in the geologic record and involves both interglacial-glacial scale transitions and the longer-term evolution of climate over the last 100 million years. Records from the Cenozoic clearly show that the long-term trend is characterized by numerous abrupt steps where the system appears to be rapidly moving to a new equilibrium state. The long-term trend probably is due to changes associated with plate tectonic processes, but the abrupt steps most likely reflect instabilities in the climate system as the slowly changing boundary conditions caused the climate to reach some threshold critical point. A more detailed analysis of abrupt steps comes from high-resolution studies of glacial-interglacial fluctuations in the Pleistocene. Comparison of climate transitions with the extinction record indicates that many climate and biotic transitions coincide. The Cretaceous-Tertiary extinction is not a candidate for an extinction event due to instabilities in the climate system. It is quite possible that more detailed comparisons and analysis will indicate some flaws in the climate instability-extinction hypothesis, but at present it appears to be a viable candidate as an alternate mechanism for causing abrupt environmental changes and extinctions.

  14. Recent Trends of Tree Growth in Relation to Climate Change in Hungary

    Directory of Open Access Journals (Sweden)

    SOMOGYI, Zoltán

    2008-01-01

    Full Text Available The paper addresses two related issues. One is whether, and how, growth patterns of standmean height have changed in Hungary in the last few decades, and the other is whether recentlyobserved increases in mean annual temperature might have caused changes in growth trends. Changesin tree growth were investigated for beech (Fagus sylvatica, sessile oak (Quercus petraea andTurkey oak (Quercus cerris by comparing stand mean heights over age using data from the forestinventories of 1981 and 2001, and for sessile oak using stand mean height data from permanentsample plots since 1961. Tree growth was found to have accelerated for each species mentioned, withTurkey oak showing the largest acceleration. To study the second issue, stand mean height was relatedto elevation, wich in turn was related to mean annual temperature and precipitation. For theseanalyses, too, data of many thousands of stands in the forest inventory was used. Stand mean heightwas found to increase with decreasing elevation, i.e. with increasing mean annual temperature, foreach of the three species. As the annual precipitation and air humidity decreases with decreasingelevation, it was concluded that increases of mean annual temperature could positively have affectedtree growth in the last few decades. However, this effect is expected to be soon limited by wateravailability.

  15. Hydro-climatic trends and water resource management implications based on multi-scale data for the Lake Victoria region, Kenya

    Science.gov (United States)

    Koutsouris, A. J.; Destouni, G.; Jarsjö, J.; Lyon, S. W.

    2010-07-01

    Unreliable rainfall may be a main cause of poverty in rural areas, such as the Kisumu district by Lake Victoria in Kenya. Climate change may further increase the negative effects of rainfall uncertainty. These effects could be mitigated to some extent through improved and adaptive water resource management and planning, which relies on our interpretations and projections of the coupled hydro-climatic system behaviour and its development trends. In order to identify and quantify the main differences and consistencies among such hydro-climatic assessments, this study investigates trends and exemplifies their use for important water management decisions for the Lake Victoria drainage basin (LVDB), based on local scale data for the Orongo village in the Kisumu district, and regional scale data for the whole LVDB. Results show low correlation between locally and regionally observed hydro-climatic trends, and large differences, which in turn affects assessments of important water resource management parameters. However, both data scales converge in indicating that observed local and regional hydrological discharge trends are primarily driven by local and regional water use and land use changes.

  16. Hydro-climatic trends and water resource management implications based on multi-scale data for the Lake Victoria region, Kenya

    International Nuclear Information System (INIS)

    Unreliable rainfall may be a main cause of poverty in rural areas, such as the Kisumu district by Lake Victoria in Kenya. Climate change may further increase the negative effects of rainfall uncertainty. These effects could be mitigated to some extent through improved and adaptive water resource management and planning, which relies on our interpretations and projections of the coupled hydro-climatic system behaviour and its development trends. In order to identify and quantify the main differences and consistencies among such hydro-climatic assessments, this study investigates trends and exemplifies their use for important water management decisions for the Lake Victoria drainage basin (LVDB), based on local scale data for the Orongo village in the Kisumu district, and regional scale data for the whole LVDB. Results show low correlation between locally and regionally observed hydro-climatic trends, and large differences, which in turn affects assessments of important water resource management parameters. However, both data scales converge in indicating that observed local and regional hydrological discharge trends are primarily driven by local and regional water use and land use changes.

  17. Hydro-climatic trends and water resource management implications based on multi-scale data for the Lake Victoria region, Kenya

    Energy Technology Data Exchange (ETDEWEB)

    Koutsouris, A J; Destouni, G; Jarsjoe, J; Lyon, S W, E-mail: steve.lyon@natgeo.su.se [Bert Bolin Centre for Climatic Research, Department of Physical Geography and Quaternary Geology, Stockholm University, 106 91 Stockholm (Sweden)

    2010-07-15

    Unreliable rainfall may be a main cause of poverty in rural areas, such as the Kisumu district by Lake Victoria in Kenya. Climate change may further increase the negative effects of rainfall uncertainty. These effects could be mitigated to some extent through improved and adaptive water resource management and planning, which relies on our interpretations and projections of the coupled hydro-climatic system behaviour and its development trends. In order to identify and quantify the main differences and consistencies among such hydro-climatic assessments, this study investigates trends and exemplifies their use for important water management decisions for the Lake Victoria drainage basin (LVDB), based on local scale data for the Orongo village in the Kisumu district, and regional scale data for the whole LVDB. Results show low correlation between locally and regionally observed hydro-climatic trends, and large differences, which in turn affects assessments of important water resource management parameters. However, both data scales converge in indicating that observed local and regional hydrological discharge trends are primarily driven by local and regional water use and land use changes.

  18. Trends and Issues in California's Low Carbon Fuel Standard - Learning from Response to Existing Climate Policy

    Science.gov (United States)

    Witcover, J.

    2015-12-01

    emissions in transportation, as other jurisdictions weigh similar climate policies and debate mechanisms and costs and California announced an ambitious target of halving petroleum use by 2030.

  19. Cenozoic calcretes from the Teruel Graben, Spain: microstructure, stable isotope geochemistry and environmental significance

    Science.gov (United States)

    Alonso-Zarza, A. M.; Arenas, C.

    2004-05-01

    In the Teruel Graben (northeast Spain), laminar and nodular calcretes formed in a variety of Cenozoic deposits, ranging in age from Palaeogene to Pleistocene. These calcretes developed in a relatively small area under the influence of the same highlands. Consequently, differences in their microstructure and isotopic composition (C and O) must be related to differences in host rock, climate, vegetation and duration of development. Nine profiles developed in different sedimentary settings, from proximal areas to lacustrine environments, were studied to determine whether the microstructure and stable isotope composition changed during the Cenozoic. These characteristics might be used as indicators of the prevailing climate and vegetation, and reveal any changes that occurred during this time. Most of the laminar calcretes studied are compound profiles that formed on hard substrates (e.g., Jurassic limestones) or coarse detrital deposits (e.g., Palaeogene, Pliocene and Plio-Pleistocene sandstones and conglomerates). These profiles formed in proximal areas of the basin and also in fluvial terraces. Microstructures include biogenic features such as alveolar septal structures, root tubes, calcified root cells and calcified organic filaments. Underside coatings of micrite and fibrous vadose cements are common around gravel clasts. On the other side, spherulites are only preserved at the very top of the youngest calcretes. Nodular calcretes developed on fine detrital substrates (e.g., on Palaeogene, Miocene and Pliocene red mudstones and sandy mudstones of distal alluvial and floodplain environments), and in some places grade vertically into palustrine limestones. The nodules consist of micrite and were elongated vertically, show desiccation cracks and mottling, micritic coatings, some alveolar septal structures, and root traces. Microcodium of type 1 occurs in both laminar and nodular calcretes, but only in those of Palaeogene age, while calcified root cells ( Microcodium

  20. Trends in atmospheric concentrations of weed pollen in the context of recent climate warming in Poznań (Western Poland)

    Science.gov (United States)

    Bogawski, Paweł; Grewling, Łukasz; Nowak, Małgorzata; Smith, Matt; Jackowiak, Bogdan

    2014-10-01

    A significant increase in summer temperatures has been observed for the period 1996-2011 in Poznań, Poland. The phenological response of four weed taxa, widely represented by anemophilous species ( Artemisia spp., Rumex spp. and Poaceae and Urticaceae species) to this recent climate warming has been analysed in Poznań by examining the variations in the course of airborne pollen seasons. Pollen data were collected by 7-day Hirst-type volumetric trap. Trends in pollen seasons were determined using Mann-Kendall test and Sen's slope estimator, whereas the relationships between meteorological and aerobiological data were established by Spearman's rank correlation coefficient. Significant trends in pollen data were detected. The duration of pollen seasons of all analysed taxa increased (from +2.0 days/year for Urticaceae to +3.8 days/year for Rumex), which can be attributed to a delay in pollen season end dates rather than earlier start dates. In addition, the intensity of Artemisia pollen seasons significantly decreased and correlates with mean July-September daily minimum temperatures ( r = -0.644, p weed pollen seasons in Poznań, i.e. longer duration and later end dates, might be caused by the recorded increase in summer temperature. This influence was the strongest in relation to Artemisia, which is the taxon that flowers latest in the year. The general lack of significant correlations between Rumex and Urticaceae pollen seasons and spring and/or summer temperature suggests that other factors, e.g. land use practices, could also be partially responsible for the observed shifts in pollen seasons.

  1. Clinical Malaria Transmission Trends and Its Association with Climatic Variables in Tubu Village, Botswana: A Retrospective Analysis

    Science.gov (United States)

    Chimbari, Moses John; Ngwenya, Barbara Ntombi; Sartorius, Benn

    2016-01-01

    Good knowledge on the interactions between climatic variables and malaria can be very useful for predicting outbreaks and preparedness interventions. We investigated clinical malaria transmission patterns and its temporal relationship with climatic variables in Tubu village, Botswana. A 5-year retrospective time series data analysis was conducted to determine the transmission patterns of clinical malaria cases at Tubu Health Post and its relationship with rainfall, flood discharge, flood extent, mean minimum, maximum and average temperatures. Data was obtained from clinical records and respective institutions for the period July 2005 to June 2010, presented graphically and analysed using the Univariate ANOVA and Pearson cross-correlation coefficient tests. Peak malaria season occurred between October and May with the highest cumulative incidence of clinical malaria cases being recorded in February. Most of the cases were individuals aged >5 years. Associations between the incidence of clinical malaria cases and several factors were strong at lag periods of 1 month; rainfall (r = 0.417), mean minimum temperature (r = 0.537), mean average temperature (r = 0.493); and at lag period of 6 months for flood extent (r = 0.467) and zero month for flood discharge (r = 0.497). The effect of mean maximum temperature was strongest at 2-month lag period (r = 0.328). Although malaria transmission patterns varied from year to year the trends were similar to those observed in sub-Saharan Africa. Age group >5 years experienced the greatest burden of clinical malaria probably due to the effects of the national malaria elimination programme. Rainfall, flood discharge and extent, mean minimum and mean average temperatures showed some correlation with the incidence of clinical malaria cases. PMID:26983035

  2. Clinical Malaria Transmission Trends and Its Association with Climatic Variables in Tubu Village, Botswana: A Retrospective Analysis.

    Science.gov (United States)

    Chirebvu, Elijah; Chimbari, Moses John; Ngwenya, Barbara Ntombi; Sartorius, Benn

    2016-01-01

    Good knowledge on the interactions between climatic variables and malaria can be very useful for predicting outbreaks and preparedness interventions. We investigated clinical malaria transmission patterns and its temporal relationship with climatic variables in Tubu village, Botswana. A 5-year retrospective time series data analysis was conducted to determine the transmission patterns of clinical malaria cases at Tubu Health Post and its relationship with rainfall, flood discharge, flood extent, mean minimum, maximum and average temperatures. Data was obtained from clinical records and respective institutions for the period July 2005 to June 2010, presented graphically and analysed using the Univariate ANOVA and Pearson cross-correlation coefficient tests. Peak malaria season occurred between October and May with the highest cumulative incidence of clinical malaria cases being recorded in February. Most of the cases were individuals aged >5 years. Associations between the incidence of clinical malaria cases and several factors were strong at lag periods of 1 month; rainfall (r = 0.417), mean minimum temperature (r = 0.537), mean average temperature (r = 0.493); and at lag period of 6 months for flood extent (r = 0.467) and zero month for flood discharge (r = 0.497). The effect of mean maximum temperature was strongest at 2-month lag period (r = 0.328). Although malaria transmission patterns varied from year to year the trends were similar to those observed in sub-Saharan Africa. Age group >5 years experienced the greatest burden of clinical malaria probably due to the effects of the national malaria elimination programme. Rainfall, flood discharge and extent, mean minimum and mean average temperatures showed some correlation with the incidence of clinical malaria cases. PMID:26983035

  3. Tropical cyclone losses in the USA and the impact of climate change - A trend analysis based on data from a new approach to adjusting storm losses

    International Nuclear Information System (INIS)

    Economic losses caused by tropical cyclones have increased dramatically. Historical changes in losses are a result of meteorological factors (changes in the incidence of severe cyclones, whether due to natural climate variability or as a result of human activity) and socio-economic factors (increased prosperity and a greater tendency for people to settle in exposed areas). This paper aims to isolate the socio-economic effects and ascertain the potential impact of climate change on this trend. Storm losses for the period 1950-2005 have been adjusted to the value of capital stock in 2005 so that any remaining trend cannot be ascribed to socio-economic developments. For this, we introduce a new approach to adjusting losses based on the change in capital stock at risk. Storm losses are mainly determined by the intensity of the storm and the material assets, such as property and infrastructure, located in the region affected. We therefore adjust the losses to exclude increases in the capital stock of the affected region. No trend is found for the period 1950-2005 as a whole. In the period 1971-2005, since the beginning of a trend towards increased intense cyclone activity, losses excluding socio-economic effects show an annual increase of 4% per annum. This increase must therefore be at least due to the impact of natural climate variability but, more likely than not, also due to anthropogenic forcings.

  4. Late Cenozoic fluvial dynamics of the River Tana, Kenya, an uplift dominated record

    Science.gov (United States)

    Veldkamp, A.; Buis, E.; Wijbrans, J. R.; Olago, D. O.; Boshoven, E. H.; Marée, M.; van den Berg van Saparoea, R. M.

    2007-11-01

    The Late Cenozoic development of the River Tana in Kenya has been reconstructed for its central reach near its confluence with the River Mutonga, which drains the Mount Kenya region. Age control for this system has been provided by K-Ar and Ar-Ar dating. Between 3.21 and 2.65 Ma a major updoming occurred, in relation to the formation of the Kenyan rift valley. The tilting related to this doming has been reconstructed from lava flows that preserve former river gradients. Linear projection of these trends to the current rift valley rim suggests a net updoming of the eastern Gregory Rift valley by at least ∼1 km during 3.21-2.65 Ma. In contrast, since 2.65 Ma the Tana system has been mainly subject to relatively minor epeirogenic uplift. Changing climatic conditions combined with continuing uplift yielded a typical staircase of strath terraces with at least 10 distinct levels. A more detailed reconstruction of the incision rates since 215 ka has been made, by correlating mineralogically fingerprinted volcaniclastic Tana deposits with dated tephras in a lake record. These volcaniclastic sediments were deposited during glacial periods, contemporaneous with lahars. The reconstructed incision rates for the three youngest terraces are ∼0.1-0.2 mm a-1, thus considerably faster than the overall average rate of valley incision since the Mid-Pliocene, of 0.06 mm a-1. A plausible uplift history has been reconstructed using the estimated ages of the Tana terraces and marine terraces on the Indian Ocean coastline. The result suggests an increase in the rate of incision by the River Tana at ∼0.9 Ma, an observation typical in most European river terrace staircases. The reconstructed Late Quaternary development of Tana valley indicates that a similar Quaternary uplift mechanism has operated in both Europe and East Kenya, suggesting a globally applicable process.

  5. Climatic warming above the Arctic Circle: are there trends in timing and length of the thermal growing season in Murmansk Region (Russia) between 1951 and 2012?

    Science.gov (United States)

    Blinova, Ilona; Chmielewski, Frank-Michael

    2015-06-01

    Anomalies in the timing of the thermal growing season have become obvious in the NE part of Fennoscandia since 2000. They are in accordance with climatic changes reported for Europe and Fennoscandia. The actual length of the growing season reached 120 days on average, onset on 30 May and ending on 27 September (1981-2010). Shifts in the timing of the growing season and its mean prolongation by 18.5 days/62a are demonstrated for Murmansk Region (1951-2012). In this period, the onset of the growing season advanced by 7.1 days/62a, while the end was extended by 11.4 days/62a. The delay in the end of the growing season is similar to the entire Fennoscandian pattern but it has not been detected in the rest of Europe. The regional pattern of climatic regimes in Murmansk Region remained stable in comparison with earlier climatic maps (1971). However, the actual shifts in the timing of the growing season were more pronounced in colder (oceanic and mountainous) parts. Recent climatic trends could influence the retreat of the tundra zone and changes in the forest line. Losses of tundra biodiversity and enrichment of the northern taiga by southern species could be expected from present climatic trends.

  6. Current temporal trends in moth abundance are counter to predicted effects of climate change in an assemblage of subarctic forest moths.

    Science.gov (United States)

    Hunter, Mark D; Kozlov, Mikhail V; Itämies, Juhani; Pulliainen, Erkki; Bäck, Jaana; Kyrö, Ella-Maria; Niemelä, Pekka

    2014-06-01

    Changes in climate are influencing the distribution and abundance of the world's biota, with significant consequences for biological diversity and ecosystem processes. Recent work has raised concern that populations of moths and butterflies (Lepidoptera) may be particularly susceptible to population declines under environmental change. Moreover, effects of climate change may be especially pronounced in high latitude ecosystems. Here, we examine population dynamics in an assemblage of subarctic forest moths in Finnish Lapland to assess current trajectories of population change. Moth counts were made continuously over a period of 32 years using light traps. From 456 species recorded, 80 were sufficiently abundant for detailed analyses of their population dynamics. Climate records indicated rapid increases in temperature and winter precipitation at our study site during the sampling period. However, 90% of moth populations were stable (57%) or increasing (33%) over the same period of study. Nonetheless, current population trends do not appear to reflect positive responses to climate change. Rather, time-series models illustrated that the per capita rates of change of moth species were more frequently associated negatively than positively with climate change variables, even as their populations were increasing. For example, the per capita rates of change of 35% of microlepidoptera were associated negatively with climate change variables. Moth life-history traits were not generally strong predictors of current population change or associations with climate change variables. However, 60% of moth species that fed as larvae on resources other than living vascular plants (e.g. litter, lichen, mosses) were associated negatively with climate change variables in time-series models, suggesting that such species may be particularly vulnerable to climate change. Overall, populations of subarctic forest moths in Finland are performing better than expected, and their populations

  7. LATE CREATACEOUS-CENOZOIC SEDIMENTS OF THE BAIKAL RIFT BASIN AND CHANGING NATURAL CONDITIONS

    Directory of Open Access Journals (Sweden)

    Viktor D. Mats

    2015-09-01

    Full Text Available The late Cretaceous-Cenozoic sediments of fossil soils and weathering crusts of the Baikal rift have been subject to long-term studies. Based on our research results, it is possible to distinguish the following litho-stratigraphic complexes which are related to particular stages of the rift development: the late Cretaceous–early Oligocene (crypto-rift Arheo-baikalian, the late Oligocene–early Pliocene (ecto-rift early orogenic Pra-baikalian, and the late Pliocene-Quaternary (ecto-rift late orogenic Pra-baikalian – Baikalian complexes. Changes of weathering modes (Cretaceous-quarter, soil formation (Miocene-quarter and differences of precipitation by vertical and lateral stratigraphy are analysed with regard to specific features of climate, tectonics and facial conditions of sedimentation. Tectonic phases are defined in the Cenozoic period of the Pribaikalie.

  8. Evaluation of metrics and baselines for tracking greenhouse gas emissions trends: Recommendations for the California climate action registry

    Energy Technology Data Exchange (ETDEWEB)

    Price, Lynn; Murtishaw, Scott; Worrell, Ernst

    2003-06-01

    industry-specific metric for reporting and tracking GHG emissions trends to accurately reflect year to year changes while protecting proprietary data. This GHG intensity index changes while protecting proprietary data. This GHG intensity index would provide Registry participants with a means for demonstrating improvements in their energy and GHG emissions per unit of production without divulging specific values. For the second research area, Berkeley Lab evaluated various methods used to calculate baselines for documentation of energy consumption or GHG emissions reductions, noting those that use industry-specific metrics. Accounting for actions to reduce GHGs can be done on a project-by-project basis or on an entity basis. Establishing project-related baselines for mitigation efforts has been widely discussed in the context of two of the so-called ''flexible mechanisms'' of the Kyoto Protocol to the United Nations Framework Convention on Climate Change (Kyoto Protocol) Joint Implementation (JI) and the Clean Development Mechanism (CDM).

  9. Did high Neo-Tethys subduction rates contribute to early Cenozoic warming?

    Directory of Open Access Journals (Sweden)

    G. Hoareau

    2015-07-01

    Full Text Available The 58–51 Ma interval was characterized by a long-term increase of global temperatures (+4 to +6 °C up to the Early Eocene Climate Optimum (EECO, 52.9–50.7 Ma, the warmest interval of the Cenozoic. It was recently suggested that sustained high atmospheric pCO2, controlling warm early Cenozoic climate, may have been released during Neo-Tethys closure through the subduction of large amounts of pelagic carbonates and their recycling as CO2 at arc volcanoes ("carbonate subduction factory". To analyze the impact of Neo-Tethys closure on early Cenozoic warming, we have modeled the volume of subducted sediments and the amount of CO2 emitted at active arc volcanoes along the northern Tethys margin. The impact of calculated CO2 fluxes on global temperature during the early Cenozoic have then been tested using a climate carbon cycle model (GEOCLIM. We first show that CO2 production may have reached up to 1.55 × 1018 mol Ma−1 specifically during the EECO, ~ 4 to 37 % higher that the modern global volcanic CO2 output, owing to a dramatic India–Asia plate convergence increase. In addition to the background CO2 degassing, the subduction of thick Greater Indian continental margin carbonate sediments at ~ 55–50 Ma may also have led to additional CO2 production of 3.35 × 1018 mol Ma−1 during the EECO, making a total of 85 % of the global volcanic CO2 outgassed. However, climate modelling demonstrates that timing of maximum CO2 release only partially fit with the EECO, and that corresponding maximum pCO2 values (750 ppm and surface warming (+2 °C do not reach values inferred from geochemical proxies, a result consistent with conclusions arise from modelling based on other published CO2 fluxes. These results demonstrate that CO2 derived from decarbonation of Neo-Tethyan lithosphere may have possibly contributed to, but certainly cannot account alone for early Cenozoic warming, including the EECO. Other commonly cited sources of excess CO2 such as

  10. A synthesis of Cenozoic sedimentation in the North Sea

    DEFF Research Database (Denmark)

    Anell, Ingrid Anna Margareta; Thybo, Hans; Rasmussen, E.S.

    2012-01-01

    sediment influx into the North Sea during the Cenozoic is more complex than previously suggested clockwise rotation from early northwestern to late southern sources. The Shetland Platform supplied sediment continuously, although at varying rates, until the latest Cenozoic. Sedimentation around Norway...... changed from early Cenozoic influx from the southwestern margin, to almost exclusively from the southern margin in the Oligocene and from all of southern Norway in the latest Cenozoic. Thick Eocene deposits in the Central Graben are sourced mainly from a western and a likely southern source, indicating...

  11. Trend analysis to determine hazards related to climate change in the andean agricultural areas of cundinamarca and boyacá

    OpenAIRE

    2012-01-01

    Recognizing the threat from climate change that is facing and will face agro ecosystems is the first step in determining adaptation to climate change. One way is through Global Climate Models (GCMs), but their spatial resolution is not best suited for making decisions locally, further reducing scale, seen as a way to resolve the resolution problem, has not yielded the expected results. This study puts forth an exercise in which we study the climatic time series of precipitation and temperatur...

  12. Influence of climate and land use changes on recent trend of soil erosion within the Russian Plain

    Science.gov (United States)

    Golosov, Valentin; Yermolaev, Oleg; Rysin, Ivan; Litvin, Leonid; Kiryukhina, Zoya; Safina, Guzel

    2016-04-01

    flood levels decreased considerably - in particular, in small rivers. This is confirmed by a serious decrease of floodplain sedimentation rates since 1986 compared with the period from 1964 to 1986. As a result of both positive trend of extreme rainfall and negative trend of surface snow melting runoff, the proportion of sediments eroded from cultivated slopes and delivered by surface runoff to river channels decreased considerably during the last few decades in the southern part of the Russian Plain. Complex assessment of different erosion factors changes is undertaken for the different landscape zones of the Russian Plain. Given analysis allows evaluating of recent trend in erosion rates from cultivated lands. The other indicators of sediment redistribution dynamic (gully head retreat rate, floodplain sedimentation) are also used for assessment of soil erosion rate dynamic under land use and climate changes during last 25-30 years.

  13. The Norwegian Danish Basin: A key to understanding the Cenozoic in the eastern North Sea

    Science.gov (United States)

    Rasmussen, Thomas L.; Clausen, Ole R.; Andresen, Katrine J.; Goledowski, Bartosz

    2015-04-01

    The Danish part of Norwegian-Danish Basin, which constitutes the eastern part of the North Sea Basin, has been the key area for sequence stratigraphic subdivision and analysis of the Cenozoic succession since the mid 1990's. Widespread 3D seismic data, in the central parts of the North Sea Basin, as well as more scattered 3D seismic data in the Danish part of the Norwegian-Danish Basin, have given a more detailed understanding of the sequences and indicate that climate is tenable for the origin of Cenozoic sequence boundaries. The previous sequence stratigraphic interpretations have been an integrated part of an ongoing debate concerning vertical movements of the Fennoscandian shield versus the impact of climate and erosion. A newly accessed coherent regional 2D and reprocessed 3D seismic data set, in the Norwegian part of the Norwegian-Danish Basin, constitute the database for a new sequence stratigraphic analysis of the entire area. The objective of the new study is to test previous subdivisions and introduce a coherent 3D sequence stratigraphic analysis and depositional model for the entire Norwegian-Danish Basin. This analysis is necessary to get out of the stalemate with the uplift discussion. The study shows that the original subdivision by Michelsen et al. (1995, 1998) stands. However, revision of few a sequence boundaries may have to be adjusted due to new biostratigraphic information published. Furthermore, high-angle clinoforms and geomorphological transport complexes observed in the Danish North Sea Basin can be traced into the Norwegian sector. This together with the recognition of several other high-angle clinoform complexes, and their associated seismic facies distribution maps and thickness-maps, enhances the level of detail and constrains the previous published paleogeographic reconstructions of the Cenozoic. The geometry of the Cenozoic infill, in the Norwegian part of the Norwegian-Danish Basin, is here interpreted to be controlled by relative sea

  14. Assessing the potential impact and uncertainty of climate, land use change and demographic trends on malaria transmission in Africa by 2050.

    Science.gov (United States)

    Tompkins, Adrian; Caporaso, Luca; Colon-Gonzalez, Felipe

    2014-05-01

    Previous analyses of data has shown that in addition to variability and longer term trends in climate variables, both land use change (LUC) and population mobility and urbanisation trends can impact malaria transmission intensities and socio-economic burden. With the new regional VECTRI dynamical malaria model it is now possible to examine these in an integrated modelling framework. Using 5 global climate models which were bias corrected using the WATCH data for the recent ISIMIP project, the four Representative Concentration Pathways (RCP), population projections disaggregated from the Shared Socioeconomic Pathways (SSP) and Land use change from the HYDE model output used in the CMIP5 process, we construct a multi-member ensemble of malaria transmission intensity projections for 2050. The ensemble integrations indicate that climate has the leading impact on malaria changes, but that population growth and urbanisation can offset the effect of climate locally. LUC impacts can also be significant on the local scale but their assessment is highly uncertain and only indicative in this study. It is argued that the study should be repeated with a range of malaria models or VECTRI configurations in order to assess the additional uncertainty due to the malaria model assumptions.

  15. On the ability of statistical wind-wave models to capture the variability and long-term trends of the North Atlantic winter wave climate

    Science.gov (United States)

    Martínez-Asensio, Adrián; Marcos, Marta; Tsimplis, Michael N.; Jordà, Gabriel; Feng, Xiangbo; Gomis, Damià

    2016-07-01

    A dynamical wind-wave climate simulation covering the North Atlantic Ocean and spanning the whole 21st century under the A1B scenario has been compared with a set of statistical projections using atmospheric variables or large scale climate indices as predictors. As a first step, the performance of all statistical models has been evaluated for the present-day climate; namely they have been compared with a dynamical wind-wave hindcast in terms of winter Significant Wave Height (SWH) trends and variance as well as with altimetry data. For the projections, it has been found that statistical models that use wind speed as independent variable predictor are able to capture a larger fraction of the winter SWH inter-annual variability (68% on average) and of the long term changes projected by the dynamical simulation. Conversely, regression models using climate indices, sea level pressure and/or pressure gradient as predictors, account for a smaller SWH variance (from 2.8% to 33%) and do not reproduce the dynamically projected long term trends over the North Atlantic. Investigating the wind-sea and swell components separately, we have found that the combination of two regression models, one for wind-sea waves and another one for the swell component, can improve significantly the wave field projections obtained from single regression models over the North Atlantic.

  16. Intercomparison of CMIP5 and CMIP3 simulations of the 20th century maximum and minimum temperatures over India and detection of climatic trends

    Science.gov (United States)

    Sonali, P.; Kumar, D. Nagesh; Nanjundiah, Ravi S.

    2016-01-01

    Climate change impact assessment has become one of the most important subjects of the research community because of the recent increase in frequency of extreme events and changes in the spatiotemporal patterns of climate. This paper analyses the ability of 46 coupled climate models from Coupled Model Intercomparison Project phases 3 and 5 (CMIP5 and CMIP3). The performance of each climate model was assessed based on its skills in simulating the current seasonal cycles (monthly) of both maximum temperature and minimum temperature (Tmax, Tmin) over India. The performance measures such as coefficient of correlation (Skill_r), root mean square error (Skill_rmse), and the skill in simulating the observed probability density function (Skill_s) are mainly employed for evaluation of the simulated monthly seasonal cycle. A new metric called Skill_All which is an intersection of the above three metrics has been defined for the first time. A notable enhancement of Skill_All for CMIP5 vis-a-vis CMIP3 is observed. Further, three best CMIP5 models each for Tmax and Tmin were selected. The methodology employed in this study for model assessment is implemented for the first time for India, which establishes a robust foundation for the climate impact assessment study. The seasonal trends in Tmax and Tmin were analyzed over all the temperature homogenous regions of India for different time slots during the 20th century. Significant trends in Tmin can be seen during most of the seasons over the entire Indian region during last four decades. This establishes the signature of climate change over most parts of India.

  17. Early cenozoic differentiation of polar marine faunas.

    Directory of Open Access Journals (Sweden)

    J Alistair Crame

    Full Text Available The widespread assumption that the origin of polar marine faunas is linked to the onset of major global cooling in the Late Eocene-Early Oligocene is being increasingly challenged. The Antarctic fossil record in particular is suggesting that some modern Southern Ocean taxa may have Early Eocene or even Paleocene origins, i.e. well within the Early Cenozoic greenhouse world. A global analysis of one of the largest marine clades at the present day, the Neogastropoda, indicates that not only is there a decrease in the number of species from the tropics to the poles but also a decrease in the evenness of their distribution. A small number of neogastropod families with predominantly generalist trophic strategies at both poles points to the key role of seasonality in structuring the highest latitude marine assemblages. A distinct latitudinal gradient in seasonality is temperature-invariant and would have operated through periods of global warmth such as the Early Cenozoic. To test this concept a second global analysis was undertaken of earliest Cenozoic (Paleocene neogastropods and this does indeed show a certain degree of faunal differentiation at both poles. The Buccinidae, s.l. is especially well developed at this time, and this is a major generalist taxon at the present day. There is an element of asymmetry associated with this development of Paleocene polar faunas in that those in the south are more strongly differentiated than their northern counterparts; this can in turn be linked to the already substantial isolation of the southern high latitudes. The key role of seasonality in the formation of polar marine faunas has implications for contemporary ecosystem structure and stability.

  18. Trend and climatic sensitivity of vegetation phenology in semiarid and arid ecosystems in the US Great Basin during 1982–2011

    Directory of Open Access Journals (Sweden)

    G. Tang

    2015-07-01

    Full Text Available We quantified the temporal trend and climatic sensitivity of vegetation phenology in dryland ecosystems in the US Great Basin during 1982–2011. Our results indicated that vegetation greenness in the Great Basin increased significantly during the study period, and this positive trend occurred in autumn but not spring and summer. Spatially, increases in vegetation greenness were more apparent in the northwestern, southeastern, and eastern Great Basin but less apparent in the central and southwestern Great Basin. In addition, the start of growing season (SOS was not advanced while the end of growing season (EOS was delayed significantly at a rate of 3.0 days per decade during the study period. The significant delay in EOS and lack of earlier leaf onset caused growing season length (GSL to increase at a rate of 3.0 days per decade during 1982–2011. Interestingly, we found that the variation of mean vegetation greenness in the period of March to November (SSA was not significantly correlated with its mean surface air temperature but was strongly correlated with its total precipitation. Seasonally, the variation of mean vegetation greenness in spring, summer, and autumn was mainly attributable to changes in pre-season precipitation in winter and spring. Nevertheless, climate warming played a strong role in extending GSL that in turn resulted in the upward trend in mean vegetation greenness during 1982–2011. Overall, our results suggested that changes in wintertime and springtime precipitation played a stronger role than temperature in affecting the interannual variability of vegetation greenness while climate warming was mainly responsible for the 30-year upward trend in the magnitudes of mean vegetation greenness in the dryland ecosystems during 1982–2011.

  19. Impact of socio-economic trends and climate variability on the occurrence and severity of blue water shortage and stress events at the global scale

    Science.gov (United States)

    Veldkamp, Ted I. E.; Wada, Yoshihide; de Moel, Hans; Kummu, Matti; Aerts, Jeroen C. J. H.; Ward, Philip J.

    2014-05-01

    Changes in available fresh water resources (i.e. water in rivers, lakes, and reservoirs), together with changes in water use, force our society to adapt continuously to drought and water scarcity conditions. The inadequate amount of fresh water is recognized as one of the most important global risks for the near future. Whilst several studies assess the role of long term climate change and socio-economic trends on global blue water availability and scarcity events, the impact of climate variability is less well understood. Taking into account inter-annual climate variability, however, is important as it may offset other factors of change (e.g. socio-economic development, long term climate change) at the regional scale, impacting the efficiency of adaptation strategies. The tailoring of adaptation strategies to specific regions requires also more insights in the specific character of water scarcity events, being solely demand (sector-specific)- or population-driven, or driven by both. Only few studies, however, have executed such assessment and a global analysis distinguishing water use sector- and climate variability-specific water scarcity events is lacking. In this contribution, we evaluate the impact of socio-economic trends and inter-annual climate variability on the occurrence and severity of blue water scarcity events. This is done at the global scale over the time period 1960-2000, while distinguishing two main types of scarcity: apparent, demand-driven, water stress and real, population-driven, water shortage. Subsequently, demand-driven water stress was broken down into water stress being solely irrigation-, economy-, or population-driven, or driven by all the causes. The results indicate that both socio-economic trends and climate variability impact the frequency and severity of water shortage and stress events. The results differ significantly regionally, both in sign (+/-) and in relative contribution. Furthermore, the results show a spatial

  20. Climatic effects of 1950–2050 changes in US anthropogenic aerosols – Part 1: Aerosol trends and radiative forcing

    Directory of Open Access Journals (Sweden)

    D. G. Streets

    2012-04-01

    Full Text Available We calculate decadal aerosol direct and indirect (warm cloud radiative forcings from US anthropogenic sources over the 1950–2050 period. Past and future aerosol distributions are constructed using GEOS-Chem and historical emission inventories and future projections from the IPCC A1B scenario. Aerosol simulations are evaluated with observed spatial distributions and 1980–2010 trends of aerosol concentrations and wet deposition in the contiguous US. Direct and indirect radiative forcing is calculated using the GISS general circulation model and monthly mean aerosol distributions from GEOS-Chem. The radiative forcing from US anthropogenic aerosols is strongly localized over the eastern US. We find that its magnitude peaked in 1970–1990, with values over the eastern US (east of 100° W of −2.0 W m−2 for direct forcing including contributions from sulfate (−2.0 W m−2, nitrate (−0.2 W m−2, organic carbon (−0.2 W m−2, and black carbon (+0.4 W m−2. The uncertainties in radiative forcing due to aerosol radiative properties are estimated to be about 50%. The aerosol indirect effect is estimated to be of comparable magnitude to the direct forcing. We find that the magnitude of the forcing declined sharply from 1990 to 2010 (by 0.8 W m−2 direct and 1.0 W m−2 indirect, mainly reflecting decreases in SO2 emissions, and project that it will continue declining post-2010 but at a much slower rate since US SO2 emissions have already declined by almost 60% from their peak. This suggests that much of the warming effect of reducing US anthropogenic aerosol sources has already been realized. The small positive radiative forcing from US BC emissions (+0.3 W m−2 over the eastern US in 2010; 5% of the global forcing from anthropogenic BC emissions worldwide suggests that a US emission control strategy focused on BC would have only limited climate benefit.

  1. Spatial and temporal trends in summertime climate and water quality indicators in the coastal embayments of Buzzards Bay, Massachusetts

    Directory of Open Access Journals (Sweden)

    J. E. Rheuban

    2015-08-01

    Full Text Available Degradation of coastal ecosystems by eutrophication is largely defined by nitrogen loading from land via surface and groundwater flows. However, indicators of water quality are highly variable due to a myriad of other drivers, including temperature and precipitation. To evaluate these drivers, we examined spatial and temporal trends in a 22 year record of summer water quality data from 122 stations in 17 embayments within Buzzards Bay, MA (USA, collected through a citizen science monitoring program managed by Buzzards Bay Coalition. To identify spatial patterns across Buzzards Bay's embayments, we used a principle component and factor analysis and found that rotated factor loadings indicated little correlation between inorganic nutrients and organic matter and chlorophyll a (Chl a concentration. Factor scores showed that embayment geomorphology in addition to nutrient loading was a strong driver of water quality, where embayments with surface water inputs showed larger biological impacts than embayments dominated by groundwater influx. A linear regression analysis of annual summertime water quality indicators over time revealed that from 1992 to 2013, most embayments (15 of 17 exhibited an increase in temperature (mean rate of 0.082 ± 0.025 (SD °C yr−1 and Chl a (mean rate of 0.0171 ± 0.0088 log10 (Chl a; mg m−3 yr−1, equivalent to a 4.0 % increase per year. However, only 7 embayments exhibited an increase in total nitrogen (TN concentration (mean rate 0.32 ± 0.47 (SD μM yr−1. Average summertime log10 (TN and log10 (Chl a were correlated with an indication that yield of Chl a per unit total nitrogen increased with time suggesting the estuarine response to TN may have changed because of other stressors such as warming, altered precipitation patterns, or changing light levels. These findings affirm that nitrogen loading and physical aspects of embayments are essential in explaining observed ecosystem response. However, climate

  2. Spatial and temporal trends in summertime climate and water quality indicators in the coastal embayments of Buzzards Bay, Massachusetts

    Science.gov (United States)

    Rheuban, J. E.; Williamson, S.; Costa, J. E.; Glover, D. M.; Jakuba, R. W.; McCorkle, D. C.; Neill, C.; Williams, T.; Doney, S. C.

    2016-01-01

    Degradation of coastal ecosystems by eutrophication is largely defined by nitrogen loading from land via surface water and groundwater flows. However, indicators of water quality are highly variable due to a myriad of other drivers, including temperature and precipitation. To evaluate these drivers, we examined spatial and temporal trends in a 22-year record of summer water quality data from 122 stations in 17 embayments within Buzzards Bay, MA (USA), collected through a citizen science monitoring program managed by Buzzards Bay Coalition. To identify spatial patterns across Buzzards Bay's embayments, we used a principle component and factor analysis and found that rotated factor loadings indicated little correlation between inorganic nutrients and organic matter or chlorophyll a (Chl a) concentration. Factor scores showed that embayment geomorphology in addition to nutrient loading was a strong driver of water quality, where embayments with surface water inputs showed larger biological impacts than embayments dominated by groundwater influx. A linear regression analysis of annual summertime water quality indicators over time revealed that from 1992 to 2013, most embayments (15 of 17) exhibited an increase in temperature (mean rate of 0.082 ± 0.025 (SD) °C yr-1) and Chl a (mean rate of 0.0171 ± 0.0088 log10 (Chl a; mg m-3) yr-1, equivalent to a 4.0 % increase per year). However, only seven embayments exhibited an increase in total nitrogen (TN) concentration (mean rate 0.32 ± 0.47 (SD) µM yr-1). Average summertime log10(TN) and log10(Chl a) were correlated with an indication that the yield of Chl a per unit total nitrogen increased with time suggesting the estuarine response to TN may have changed because of other stressors such as warming, altered precipitation patterns, or changing light levels. These findings affirm that nitrogen loading and physical aspects of embayments are essential in explaining the observed ecosystem response. However, climate

  3. Construction of the seawater 87Sr/86Sr curve for the Cenozoic and Cretaceous: supporting data

    International Nuclear Information System (INIS)

    We present the data used to construct the Cenozoic and Cretaceous portion of the Phanerozoic curve of seawater 87Sr/86Sr that had been given in summary form by W.H. Burke and coworkers. All Cenozoic samples (128) and 22 Cretaceous samples are foram-nannofossil oozes and limestones from DSDP cores distributed among 13 sites in the Atlantic, Pacific and Indian Oceans, and the Caribbean Sea. Non-DSDP Cretaceous samples (126) include limestone, anhydrite and phosphate samples from North America, Europe and Asia. Determination of the 87Sr/86Sr value of seawater at particular times in the past is based on comparison of ratios derived from coeval marine samples from widely separated geographic areas. The general configuration of the Cenozoic and Cretaceous curve appears to be strongly influenced by the history of plate interactions and sea-floor spreading. Specific rises and falls in the 87Sr/86Sr of seawater, however, may be caused by a variety of factors such as variation in lithologic composition of the crust exposed to weathering, configuration and topographic relief of continents, volcanic activity, rate of sea-floor spreading, extent of continental inundation by epeiric seas, and variations in both climate and paleo-oceanographic conditions. Many or all of these factors are probably related to global tectonic processes, yet their combined effect on the temporal variation of seawater 87Sr/86Sr can complicate a direct plate-tectonic interpretation for portions of the seawater curve. (Auth.)

  4. Influence of two different geo-climatic zones on the prevalence and time trends of asthma symptoms among Spanish adolescents and schoolchildren

    Science.gov (United States)

    García-Marcos, Luis; Batllés-Garrido, José; Blanco-Quirós, Alfredo; García-Hernández, Gloria; Guillén-Grima, Francisco; González-Díaz, Carlos; García-Merino, Águeda; Arnedo-Pena, Alberto; Busquets-Monge, Rosa M.; Morales-Suárez-Varela, María; López-Silvarrey-Varela, Ángel; García-Andoin, Nekane

    2009-01-01

    Few studies have focused on the long-term influence of the climate on the prevalence of asthma. The aim of this study is to establish the influence of geo-climatic conditions on the prevalence of asthma symptoms both in adolescents and schoolchildren, and to discover if this influence is associated with their time trends. Eight centres in Spain performed both ISAAC phases I (1994) and III (2002) in children 13-14 years old. Six of them also surveyed children 6-7 years old. For each age group and phase, about 3,000 children were surveyed per centre. This study examines the prevalence of current wheeze and severe current wheeze in two different geo-climatic zones, coast and plateau, considering their relative humidity and temperature range. In both age groups, the mean asthma prevalence on the coast, for phase I and III, was significantly higher than on the plateau. Living on the plateau was an independent protective factor for current wheeze and severe current wheeze for the two age groups. Within the coastal centres, the increase of the annual relative humidity was a statistical significant risk factor for current wheeze, the same trend existing for current severe wheeze. These effects were independent of the sex and of the phase of the study. The prevalence of asthma and severe asthma symptoms is more frequent on the coast of Spain as compared to the inner plateau. This finding was repeated both in 1994 and in 2002.

  5. Climate change-associated trends in net biomass change are age dependent in western boreal forests of Canada.

    Science.gov (United States)

    Chen, Han Y H; Luo, Yong; Reich, Peter B; Searle, Eric B; Biswas, Shekhar R

    2016-09-01

    The impacts of climate change on forest net biomass change are poorly understood but critical for predicting forest's contribution to the global carbon cycle. Recent studies show climate change-associated net biomass declines in mature forest plots. The representativeness of these plots for regional forests, however, remains uncertain because we lack an assessment of whether climate change impacts differ with forest age. Using data from plots of varying ages from 17 to 210 years, monitored from 1958 to 2011 in western Canada, we found that climate change has little effect on net biomass change in forests ≤ 40 years of age due to increased growth offsetting increased mortality, but has led to large decreases in older forests due to increased mortality accompanying little growth gain. Our analysis highlights the need to incorporate forest age profiles in examining past and projecting future forest responses to climate change. PMID:27465040

  6. Recent climate change in the Arctic and its impact on contaminant pathways and interpretation of temporal trend data

    Energy Technology Data Exchange (ETDEWEB)

    Macdonald, R.W. [Institute of Ocean Sciences, Department of Fisheries and Oceans, P.O. Box 6000, Sydney, BC (Canada); Harner, T. [Meteorological Service of Canada, Environment Canada, 4905 Dufferin Street, Downsview, ON (Canada); Fyfe, J. [Meteorological Service of Canada, Centre for Climate Modelling and Analysis, 3964 Gordon Head Road, Victoria, BC (Canada)

    2005-04-15

    possibility, presently difficult to predict, is combination of immune suppression together with expanding ranges of disease vectors. Finally, biotransport through migratory species is exceptionally vulnerable to changes in migration strength or in migration pathway-in the Arctic, change in the distribution of ice and temperature may already have caused such changes. Hydrocarbons, which tend to impact surfaces, will be mostly affected by change in the ice climate (distribution and drift tracks). Perhaps the most dramatic changes will occur because our view of the Arctic Ocean will change as it becomes more amenable to transport, tourism and mineral exploration on the shelves. Radionuclides have tended not to produce a radiological problem in the Arctic; nevertheless one pathway, the ice, remains a risk because it can accrue, concentrate and transport radio-contaminated sediments. This pathway is sensitive to where ice is produced, what the transport pathways of ice are, and where ice is finally melted-all strong candidates for change during the coming century. The changes that have already occurred in the Arctic and those that are projected to occur have an effect on contaminant time series including direct measurements (air, water, biota) or proxies (sediment cores, ice cores, archive material). Although these 'system' changes can alter the flux and concentrations at given sites in a number of obvious ways, they have been all but ignored in the interpretation of such time series. To understand properly what trends mean, especially in complex 'recorders' such as seals, walrus and polar bears, demands a more thorough approach to time series by collecting data in a number of media coherently. Presently, a major reservoir for contaminants and the one most directly connected to biological uptake in species at greatest risk-the ocean-practically lacks such time series.

  7. Recent climate change in the Arctic and its impact on contaminant pathways and interpretation of temporal trend data.

    Science.gov (United States)

    Macdonald, R W; Harner, T; Fyfe, J

    2005-04-15

    possibility, presently difficult to predict, is combination of immune suppression together with expanding ranges of disease vectors. Finally, biotransport through migratory species is exceptionally vulnerable to changes in migration strength or in migration pathway-in the Arctic, change in the distribution of ice and temperature may already have caused such changes. Hydrocarbons, which tend to impact surfaces, will be mostly affected by change in the ice climate (distribution and drift tracks). Perhaps the most dramatic changes will occur because our view of the Arctic Ocean will change as it becomes more amenable to transport, tourism and mineral exploration on the shelves. Radionuclides have tended not to produce a radiological problem in the Arctic; nevertheless one pathway, the ice, remains a risk because it can accrue, concentrate and transport radio-contaminated sediments. This pathway is sensitive to where ice is produced, what the transport pathways of ice are, and where ice is finally melted-all strong candidates for change during the coming century. The changes that have already occurred in the Arctic and those that are projected to occur have an effect on contaminant time series including direct measurements (air, water, biota) or proxies (sediment cores, ice cores, archive material). Although these 'system' changes can alter the flux and concentrations at given sites in a number of obvious ways, they have been all but ignored in the interpretation of such time series. To understand properly what trends mean, especially in complex 'recorders' such as seals, walrus and polar bears, demands a more thorough approach to time series by collecting data in a number of media coherently. Presently, a major reservoir for contaminants and the one most directly connected to biological uptake in species at greatest risk-the ocean-practically lacks such time series. PMID:15866268

  8. Recent climate change in the Arctic and its impact on contaminant pathways and interpretation of temporal trend data

    International Nuclear Information System (INIS)

    possibility, presently difficult to predict, is combination of immune suppression together with expanding ranges of disease vectors. Finally, biotransport through migratory species is exceptionally vulnerable to changes in migration strength or in migration pathway-in the Arctic, change in the distribution of ice and temperature may already have caused such changes. Hydrocarbons, which tend to impact surfaces, will be mostly affected by change in the ice climate (distribution and drift tracks). Perhaps the most dramatic changes will occur because our view of the Arctic Ocean will change as it becomes more amenable to transport, tourism and mineral exploration on the shelves. Radionuclides have tended not to produce a radiological problem in the Arctic; nevertheless one pathway, the ice, remains a risk because it can accrue, concentrate and transport radio-contaminated sediments. This pathway is sensitive to where ice is produced, what the transport pathways of ice are, and where ice is finally melted-all strong candidates for change during the coming century. The changes that have already occurred in the Arctic and those that are projected to occur have an effect on contaminant time series including direct measurements (air, water, biota) or proxies (sediment cores, ice cores, archive material). Although these 'system' changes can alter the flux and concentrations at given sites in a number of obvious ways, they have been all but ignored in the interpretation of such time series. To understand properly what trends mean, especially in complex 'recorders' such as seals, walrus and polar bears, demands a more thorough approach to time series by collecting data in a number of media coherently. Presently, a major reservoir for contaminants and the one most directly connected to biological uptake in species at greatest risk-the ocean-practically lacks such time series

  9. Revisiting trends in wetness and dryness in the presence of internal climate variability and water limitations over land

    OpenAIRE

    Kumar, Sanjiv; Allan, Richard P; Zwiers, Francis; Lawrence, David M.; Dirmeyer, Paul A.

    2016-01-01

    A theoretically expected consequence of the intensification of the hydrological cycle under global warming is that on average, wet regions get wetter and dry regions get drier (WWDD). Recent studies, however, have found significant discrepancies between the expected pattern of change and observed changes over land. We assess the WWDD theory in four climate models. We find that the reported discrepancy can be traced to two main issues: (1) unforced internal climate variability strongly affects...

  10. The Cenozoic Volcanoes in Northeast China

    Institute of Scientific and Technical Information of China (English)

    LIU Jiaqi; HAN Jingtai; GUO Zhengfu

    2002-01-01

    There are more than 600 Cenozoic volcanic cones and craters with abeut 50 000 km2of lava flows in northeast China, which formed many volcanic clusters and shown the features of the continental rift - type volcanoes. Most volcanic activities in this area, especially in the east part of Songliao graben, were usually controlled by rifts and faults with the main direction of NE / NNE in parallel and become younger from the central graben towards its both sides, especially to the east continental margin. It is revealed that the volcanism occurred in northeast China was as strong as that occurred in Japan during the Miocene and the Quaternary. The Quaternary basalt that is usually distributed along river valley is called "valley basalt"while Neogene basalt usually distributed in the top of mounts is called "high position basalt". These volcanoes and volcanic rocks are usually composed of alkaline basalts with ultramafic inclusions, except Changbaishan volcano that is built by trachyte and pantellerite.

  11. Trans- and Interdisciplinarity in K-14 Climate Change Education: Trends Emerging from Recent Reports by the National Research Council

    Science.gov (United States)

    Storksdieck, M.

    2012-12-01

    A recent report by the National Research Council placed climate change or climate science education deeply into the curriculum of K-12 science education in the US (A Framework for K-12 Science Education). The NRC Framework is currently being translated into the Next Generation Science Standards (NGSS), an effort by 26 states, representing 57% of the US school-aged population, under the leadership of the educational nonprofit Achieve. A first draft version of the NGSS was made available to public audiences in June of 2012, and a revised draft will be available for a second round of reviews in later November of 2012; the final version of the NGSS which will likely feature climate change and climate science as part of Earth Systems Science, but also embedded in other areas of the science curriculum, is expected to be released in the spring of 2013. It has already become apparent, though, that successful implementation of the new standards down into effective classroom-based instruction will require a deep analysis of current and likely future barriers and opportunities for engaging K-14 students in climate change education. A recently released report on an NRC workshop conducted in 2011 summarizes these discussions (Climate Change Education in Formal Settings, K-14: A Workshop Summary). The proceedings of the workshop highlight the need to think in trans- or interdisciplinary ways about educating children in primary, secondary and early post-secondary education. This report builds on a 2010 workshop that addressed how to best reach general audiences on the issue of climate change education, particularly if the desired outcome is seen as building adaptive capacity in children and adults alike. This workshop was summarized in a report entitled Climate Change Education: Goals, Audiences, and Strategies. Opportunities for engaging students in trans- or interdisciplinary exploration of climate science or climate change-related topics, while available to K-12 students

  12. CENOZOIC VOLCANISM AND GEOTHERMAL RESOURCES IN NORTHEAST CHINA

    Institute of Scientific and Technical Information of China (English)

    WANG; Xi-kui

    2001-01-01

    Ke-qin, 1997. Paleoclimatic and environmental change since 2000a B. P. recorded in ice Core[J]. The Front of Ceo-science, 4(1): 95-100.(in Chiniese)[13]ZHANG Zhen-ke, WU Rui-jin, WANG Su-min, 1998. Paleoenvironmeal evolution during historic time reflected by frequency susceptibility of the lacustrine sediment in Daihai[J]. Geography Reaserch. 17(3) :297-300. (in Chinese)[14]ZHANG Pi-yuan, 1996. Climatic Changes During Historic Time in China[J]. Jinan: Shandong Science and Technology Press, 434-435. (in Chinese)[15]ZHANG Pi-yuan, GE Quan-sheng, 1997. The stage and abrupt ness of climatic evolution[J]. The Front of Geo-science, 4(1):122-126. (in Chinese)[16]ZHONG Wei, XIONG Hei-gang, Tashplati etal., 1998a. The preliminary study on the Spore-pollen combination of the Tagele section in Cele oasis[J]. Arid Zone Research, 15 (3):14-17. (in Chinese)[17]ZHONG Wei, XIONG Hei-gang, 1998b. Preliminary study on paleoclimatic evolution since about 12ka B.P. in Bosten Lake, southern Xinjiang, China[J]. Journal of Arid Land Resources and Enviorment, 12(3) :28-35. (in Chinese)[18]ZHU Ke-zhen. 1973, Preliminary study of climatic changes since about 5000 years in China[J]. Science in China, (2):291-296. (in Chinese)[19]CHEN Mo-xiang, WANG Ji-yang, DENG Xiao, 1994. Geothermal Resources in China[M] . Beijing: Science Press, 139 -159. (in Chinese)[20]CHEN Wen-ji, LI Da-ming, LI Qi et al. , 1992. Chronology and geochemistry of basalts in Lower Liaohe Basin[A] . In: LIU Ruo-xin. Chronology and Geochemistry of Cenozoic Volcanic Rocks in China [C] . Beijing: Seismological Press, 44-80. (in Chinese)[21]E Mo-lan, ZHAO Da-sheng, 1987. Cenozoic Basalts and Deep Source Rock Inclusions[M] . Beijing: Science Press, 86-132. (in Chinese)[22]LIU Jia-qi, 1987. Research on chronology of Cenozoic volcanic rocks in Northeast China[J]. Acta Petrologica Sinica, 3(4):21-31. (in Chinese)[23]MACHIDA H, ARAI F, 1983. Extensive ash falls in and around the Sea of Japan

  13. Mechanisms of Cenozoic deformation in the Bohai Basin, Northeast China: Physical modelling and discussions

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The Bohai Basin is a Cenozoic petroliferous extensional basin in China and has apparent geometrical and kinematic similarities with the other Meso-Cenozoic extensional basins located along the eastern margin of Eurasian Plate. However, the deformation mechanisms of the basin are still in dispute. Physcial modelling referring to the Huanghua Depression, located in the central part of the Bohai Basin was conducted employing four sets of planar sandbox experimental models with different extension directions. Only experimental results of the model with N-S extension show good structural similarity with the depression. The results also indicate that complex variations of fault strike in a rift basin are not necessarily the results of complex kinematic mechanisms or polyphase deformation. Based on comparison of experimental results with the actual structures and the good structural similarity between Huanghua Depression and the whole Bohai Basin, it is concluded that the Bohai Basin was formed by the N-S extension. The strike slip deformation along the NNE-trending border faults of the basin resulted from the N-S extension and played the role of lateral transformation for the N-S extension. In addition, according to the apparent geometrical and kinematic similarities among the Bohai Basin and other Meso-Cenozoic extensional basins located along the eastern margin of the Eurasian Plate, it is proposed that: (1) this "N-S extension" model provides a better kinematic interpretation for the formation of Bohai Basin and the other adjacent basins located along the eastern margin of the Eurasian Plate; and (2) the N-S extension was probably the effect of the "slab window" formed by the subduction of the nearly E-W trending oceanic ridge between the Kula and Pacific Plates. The "slab window" effect can also provide reasonable explanations for the phenomena that initial rifting ages of basins become progressively younger westwards along the eastern margin of the Eurasian Plate

  14. Dual scale trend analysis for evaluating climatic and anthropogenic effects on the vegetated land surface in Russia and Kazakhstan

    International Nuclear Information System (INIS)

    We present a dual scale trend analysis for characterizing and comparing two contrasting areas of change in Russia and Kazakhstan that lie less than 800 km apart. We selected a global NASA MODIS (moderate resolution imaging spectroradiometer) product (MCD43C4 and MCD43A4) at a 0.05 deg. (∼5.6 km) and 500 m spatial resolution and a 16-day temporal resolution from 2000 to 2008. We applied a refinement of the seasonal Kendall trend method to the normalized difference vegetation index (NDVI) image series at both scales. We only incorporated composites during the vegetative growing season which was delineated by start of season and end of season estimates based on analysis of normalized difference infrared index data. Trend patterns on two scales pointed to drought as the proximal cause of significant declines in NDVI in Kazakhstan. In contrast, the area of increasing NDVI trend in Russia was linked through the dual scale analysis with agricultural land cover change. The coarser scale analysis was relevant to atmospheric boundary layer processes, while the finer scale data revealed trends that were more relevant to human decision-making and regional economics.

  15. Long-term trends in tourism climate index scores for 40 stations across Iran: the role of climate change and influence on tourism sustainability

    Science.gov (United States)

    Roshan, Gholamreza; Yousefi, Robabe; Fitchett, Jennifer M.

    2016-01-01

    Tourism is a rapidly growing international sector and relies intrinsically on an amenable climate to attract visitors. Climate change is likely to influence the locations preferred by tourists and the time of year of peak travel. This study investigates the effect of climate change on the Tourism Climate Index (TCI) for Iran. The paper first calculates the monthly TCI for 40 cities across Iran for each year from 1961 to 2010. Changes in the TCI over the study period for each of the cities are then explored. Increases in TCI are observed for at least one station in each month, whilst for some months no decreases occurred. For October, the maximum of 45 % of stations demonstrated significant changes in TCI, whilst for December only 10 % of stations demonstrated change. The stations Kashan, Orumiyeh, Shahrekord, Tabriz, Torbat-e-Heidarieh and Zahedan experienced significant increases in TCI for over 6 months. The beginning of the change in TCI is calculated to have occurred from 1970 to 1980 for all stations. Given the economic dependence on oil exports, the development of sustainable tourism in Iran is of importance. This critically requires the identification of locations most suitable for tourism, now and in the future, to guide strategic investment.

  16. Analyzing global trends of different cloud types and their potential impacts on climate by using the ISCCP D2 dataset

    Institute of Scientific and Technical Information of China (English)

    DING Shouguo; SHI Guangyu; ZHAO Chunsheng

    2004-01-01

    The International Satellite Cloud Climatology Project (ISCCP) D2 dataset is used to study the global distribution of low, middle and high cloud amounts and their trends of 1983-2001. Evidences have shown that global warming has accelerated over the past 20 a and the 1990s was the warmest decade in the instrumental records since 1861. Trends of various clouds amounts over this period are analyzed by employing the linear regression method. The results show that global mean total cloud amounts, in general,have tended to reduce over the past 20 a. But there are slightly increasing by about 2% before 1987 and decreasing by about 4% since then. Cloudiness trends of both low and high clouds decrease while increase for the middle cloud.And there exist remarkable discrepancies in different regions.The preliminary analyses suggest that it is likely that the cloud change occurring over the past 20 a is a positive feedback to global warming.

  17. Space climate impact on long-term changes and trends in the ionosphere-upper atmosphere system

    Czech Academy of Sciences Publication Activity Database

    Laštovička, Jan

    Ostende: STCE, 2015. [European Space Weather Week /12./. 23.11.2015-27.11.2015, Ostende] Institutional support: RVO:68378289 Keywords : ionospheric trends * solar cycle Subject RIV: DG - Athmosphere Sciences, Meteorology http://www.stce.be/esww12/program/session_details.php?nr=12#

  18. Modern and Cenozoic records of magnesium behaviour from foraminiferal Mg isotopes

    Directory of Open Access Journals (Sweden)

    P. A. E. Pogge von Strandmann

    2014-05-01

    Full Text Available Magnesium is an element critically involved in the carbon cycle, because weathering of Ca–Mg silicates removes atmospheric CO2 into rivers, and formation of Ca–Mg carbonates in the oceans removes carbon from the ocean–atmosphere system. Hence the Mg cycle holds the potential to provide valuable insights into Cenozoic climate-system history, and the shift during this time from a greenhouse to icehouse state. We present Mg isotope ratios for the past 40 Myr using planktic foraminifers as an archive. Modern foraminifera, which discriminate against elemental and isotopically heavy Mg during calcification, show no correlation between the Mg isotope composition (δ26Mg and temperature, Mg / Ca or other parameters such as carbonate saturation (Δ CO3. However, inter-species isotopic differences imply that only well-calibrated single species should be used for reconstruction of past seawater. Seawater δ26Mg inferred from the foraminiferal record decreased from ~ 0‰ at 15 Ma, to −0.83‰ at the present day, which coincides with increases in seawater lithium and oxygen isotope ratios. It strongly suggests that neither Mg concentrations nor isotope ratios are at steady-state in modern oceans, given its ~ 10 Myr residence time. From these data, we have developed a dynamic box model to understand and constrain changes in Mg sources to the oceans (rivers and Mg sinks (dolomitisation and hydrothermal alteration. Our estimates of seawater Mg concentrations through time are similar to those independently determined by pore waters and fluid inclusions. Modelling suggests that dolomite formation and the riverine Mg flux are the primary controls on the δ26Mg of seawater, while hydrothermal Mg removal and the δ26Mg of rivers are more minor controls. Using riverine flux and isotope ratios inferred from the 87Sr / 86Sr record, the modelled Mg removal by dolomite formation shows minima in the Oligocene and at the present day (with decreasing trends from 15

  19. Preserving species populations in the boreal zone in a changing climate: contrasting trends of bird species groups in a protected area network

    Directory of Open Access Journals (Sweden)

    Raimo Virkkala

    2012-12-01

    Full Text Available A protected area network should ensure the maintenance of biodiversity. Because of climate change, species ranges are expected to move polewards, causing further demand for the protected area network to be efficient in preserving biota. We compared population changes of different bird species groups according to their habitat preferences in boreal protected areas in Finland on the basis of large-scale censuses carried out in 1981–1999 and in 2000–2009. Population densities of common forest habitat generalists remained the same between the two periods, while densities of species of conservation concern showed contrasting trends: species preferring old-growth forests increased, but those living in mires and wetlands, and species of Arctic mountains decreased. These trends are most probably connected with climate change, but successional changes in protected areas and regional habitat alteration should also be taken into account. Of species preferring old-growth forests, a larger proportion are southern than among species of mires and wetlands, or of Arctic mountains, most or all of which, respectively, had a northerly distribution. In general, northern species have decreased and southern increased with the exception of northern species of old-growth forests which had not declined. On the other hand, bird species of mires and wetlands decreased also in the northernmost protected areas although mires had not been drained in the region in contrast with southern and central Finland thus indicating that regional-scale direct habitat loss did not cause the decline of these species in the north. It is suggested that climate change effects on species in natural boreal and Arctic habitats most probably are habitat-specific with large differences in response times and susceptibility.

  20. A fractal climate response function can simulate global average temperature trends of the modern era and the past millennium

    NARCIS (Netherlands)

    Hateren, J.H. van

    2013-01-01

    A climate response function is introduced that consists of six exponential (low-pass) filters with weights depending as a power law on their e-folding times. The response of this two-parameter function to the combined forcings of solar irradiance, greenhouse gases, and SO2-related aerosols is fitted

  1. Countries’ contributions to climate change: effect of accounting for all greenhouse gases, recent trends, basic needs and technological progress

    NARCIS (Netherlands)

    Elzen, M.J.; Olivier, J.J.; Hoehne, N.E.; Janssens-Maenhout, G.

    2013-01-01

    In the context of recent discussions at the UN climate negotiations we compared several ways of calculating historical greenhouse gas (GHG) emissions, and assessed the effect of these different approaches on countries’ relative contributions to cumulative global emissions. Elements not covered befor

  2. Signatures of downgoing plate-buoyancy driven subduction in Cenozoic plate motions

    Science.gov (United States)

    Goes, S.; Capitanio, F. A.; Morra, G.; Seton, M.; Giardini, D.

    2011-01-01

    The dynamics of plate tectonics are strongly related to those of subduction. To obtain a better understanding of the driving forces of subduction, we compare relations between Cenozoic subduction motions at major trenches with the trends expected for the simplest form of subduction. i.e., free subduction, driven solely by the buoyancy of the downgoing plate. In models with an Earth-like plate stiffness (corresponding to a plate-mantle viscosity contrast of 2-3 orders of magnitude), free plates subduct by a combination of downgoing plate motion and trench retreat, while the slab is draped and folded on top of the upper-lower mantle viscosity transition. In these models, the slabs sink according to their Stokes' velocities. Observed downgoing-plate motion-plate-age trends are compatible with >80% of the Cenozoic slabs sinking according to their upper-mantle Stokes' velocity, i.e., subducting-plate motion is largely driven by upper-mantle slab pull. Only in a few cases, do young plates move at velocities that require a higher driving force (possibly supplied by lower-mantle-slab induced flow). About 80% of the Cenozoic trenches retreat, with retreat accounting for about 10% of the total convergence. The few advancing trench sections are likely affected by regional factors. The low trench motions are likely encouraged by low asthenospheric drag (equivalent to that for effective asthenospheric viscosity 2-3 orders below the upper-mantle average), and low lithospheric strength (effective bending viscosity ˜2 orders of magnitude above the upper-mantle average). Total Cenozoic trench motions are often very oblique to the direction of downgoing-plate motion (mean angle of 73°). This indicates that other forces than slab buoyancy exert the main control on upper-plate/trench motion. However, the component of trench retreat in the direction of downgoing plate motion (≈ slab pull) correlates with downgoing-plate motion, and this component of retreat generally does not

  3. Trends in the breeding population of Adelie penguins in the Ross Sea, 1981-2012: a coincidence of climate and resource extraction effects.

    Directory of Open Access Journals (Sweden)

    Phil O'B Lyver

    Full Text Available Measurements of the size of Adélie penguin (Pygoscelis adeliae colonies of the southern Ross Sea are among the longest biologic time series in the Antarctic. We present an assessment of recent annual variation and trends in abundance and growth rates of these colonies, adding to the published record not updated for more than two decades. High angle oblique aerial photographic surveys of colonies were acquired and penguins counted for the breeding seasons 1981-2012. In the last four years the numbers of Adélie penguins in the Ross and Beaufort Island colonies (southern Ross Sea metapopulation reached their highest levels since aerial counts began in 1981. Results indicated that 855,625 pairs of Adélie penguins established breeding territories in the western Ross Sea, with just over a quarter (28% of those in the southern portion, constituting a semi-isolated metapopulation (three colonies on Ross Island, one on nearby Beaufort Island. The southern population had a negative per capita growth rate of -0.019 during 1981-2000, followed by a positive per capita growth rate of 0.067 for 2001-2012. Colony growth rates for this metapopulation showed striking synchrony through time, indicating that large-scale factors influenced their annual growth. In contrast to the increased colony sizes in the southern population, the patterns of change among colonies of the northern Ross Sea were difficult to characterize. Trends were similar to southern colonies until the mid-1990s, after which the signal was lost owing to significantly reduced frequency of surveys. Both climate factors and recovery of whale populations likely played roles in the trends among southern colonies until 2000, after which depletion of another trophic competitor, the Antarctic toothfish (Dissostichus mawsoni, may explain the sharp increasing trend evident since then.

  4. Disentangling the Relative Importance of Changes in Climate and Land-Use Intensity in Driving Recent Bird Population Trends

    OpenAIRE

    Eglington, Sarah M.; Pearce-Higgins, James W.

    2012-01-01

    Threats to biodiversity resulting from habitat destruction and deterioration have been documented for many species, whilst climate change is regarded as increasingly impacting upon species' distribution and abundance. However, few studies have disentangled the relative importance of these two drivers in causing recent population declines. We quantify the relative importance of both processes by modelling annual variation in population growth of 18 farmland bird species in the UK as a function...

  5. Evaluation of metrics and baselines for tracking greenhouse gas emissions trends: Recommendations for the California climate action registry

    OpenAIRE

    Price, Lynn; Murtishaw, Scott; Worrell, Ernst

    2003-01-01

    Executive Summary: The California Climate Action Registry, which was initially established in 2000 and began operation in Fall 2002, is a voluntary registry for recording annual greenhouse gas (GHG) emissions. The purpose of the Registry is to assist California businesses and organizations in their efforts to inventory and document emissions in order to establish a baseline and to document early actions to increase energy efficiency and decrease GHG emissions. The State of California has...

  6. Effects of climatic changes and urban air pollution on the rising trends of respiratory allergy and asthma

    Directory of Open Access Journals (Sweden)

    D'Amato Gennaro

    2011-02-01

    Full Text Available Abstract Over the past two decades there has been increasing interest in studies regarding effects on human health of climate changes and urban air pollution. Climate change induced by anthropogenic warming of the earth's atmosphere is a daunting problem and there are several observations about the role of urbanization, with its high levels of vehicle emissions and other pollutants, and westernized lifestyle with respect to the rising frequency of respiratory allergic diseases observed in most industrialized countries. There is also evidence that asthmatic subjects are at increased risk of developing exacerbations of bronchial obstruction with exposure to gaseous (ozone, nitrogen dioxide, sulfur dioxide and particulate inhalable components of air pollution. A change in the genetic predisposition is an unlikely cause of the increasing frequency in allergic diseases because genetic changes in a population require several generations. Consequently, environmental factors such as climate change and indoor and outdoor air pollution may contribute to explain the increasing frequency of respiratory allergy and asthma. Since concentrations of airborne allergens and air pollutants are frequently increased contemporaneously, an enhanced IgE-mediated response to aeroallergens and enhanced airway inflammation could account for the increasing frequency of allergic respiratory diseases and bronchial asthma. Scientific societies such as the European Academy of Allergy and Clinical Immunology, European Respiratory Society and the World Allergy Organization have set up committees and task forces to produce documents to focalize attention on this topic, calling for prevention measures.

  7. Climate sensitivity, sea level and atmospheric carbon dioxide

    OpenAIRE

    Hansen, James; Sato, Makiko; Russell, Gary; Kharecha, Pushker

    2013-01-01

    Cenozoic temperature, sea level and CO2 co-variations provide insights into climate sensitivity to external forcings and sea level sensitivity to climate change. Climate sensitivity depends on the initial climate state, but potentially can be accurately inferred from precise paleoclimate data. Pleistocene climate oscillations yield a fast-feedback climate sensitivity 3 +/- 1{\\deg}C for 4 W/m2 CO2 forcing if Holocene warming relative to the Last Glacial Maximum (LGM) is used as calibration, bu...

  8. Cenozoic stratigraphy and geologic history of the Tucson Basin, Pima County, Arizona

    Science.gov (United States)

    Anderson, S.R.

    1987-01-01

    This report was prepared as part of a geohydrologic study of the Tucson basin conducted by the U.S. Geological Survey in cooperation with the city of Tucson. Geologic data from more than 500 water supply and test wells were analyzed to define characteristics of the basin sediments that may affect the potential for land subsidence induced by groundwater withdrawal. The Tucson basin is a structural depression within the Basin and Range physiographic province. The basin is 1,000 sq mi in units area and trends north to northwest. Three Cenozoic stratigraphic unit--the Pantano Formation of Oligocene age, the Tinaja beds (informal usage) of Miocene and Pliocene age, and the Fort Lowell Formation of Pleistocene age--fill the basin. The Tinaja beds include lower, middle, and upper unconformable units. A thin veneer of stream alluvium of late Quaternary age overlies the Fort Lowell Formation. The Pantano Formation and the lower Tinaja beds accumulated during a time of widespread continental sedimentation, volcanism, plutonism, uplift, and complex faulting and tilting of rock units that began during the Oligocene and continued until the middle Miocene. Overlying sediments of the middle and upper Tinaja beds were deposited in response to two subsequent episodes of post-12-million-year block faulting, the latter of which was accompanied by renewed uplift. The Fort Lowell Formation accumulated during the Quaternary development of modern through-flowing the maturation of the drainage. The composite Cenozoic stratigraphic section of the Tucson basin is at least 20,000 ft thick. The steeply tilted to flat-lying section is composed of indurated to unconsolidated clastic sediments, evaporites, and volcanic rocks that are lithologically and structurally complex. The lithology and structures of the section was greatly affected by the uplift and exhumation of adjacent metamorphic core-complex rocks. Similar Cenozoic geologic relations have been identified in other parts of southern

  9. Late Cenozoic volcanism, geochronology, and structure of the Coso Range, Inyo County, California

    Energy Technology Data Exchange (ETDEWEB)

    Duffield, W.A.; Bacon, C.R.; Dalrymple, G.B.

    1980-05-10

    The Coso Range lies at the west edge of the Great Basin, adjacent to the southern part of the Sierra Nevada. A basement complex of pre-Cenozoic plutonic and metamorphic rocks is partly buried by approx.35 km/sup 3/ of late Cenozoic volcanic rocks that were erupted during two periods, as defined by K-Ar dating: (1) 4.0--2.5 m.y., approx.31 km/sup 3/ of basalt, rhyodacite, dacite, andesite, and rhyolite, in descending order of abundance, and (2) < or =1.1 m.y., nearly equal amounts of basalt and rhyolite, most of the rhyolite being < or =0.3 m.y. old. Vents for the volcanic rocks of the younger period are localized on and near a horst of basement rocks within a concavity defined by the distribution of vents of the older period. The alignment of many vents and the presence of a considerable number of roughly north-trending normal faults of late Cenozoic age reflect basin and range tectonics dominated by roughly east-west lithospheric extension. Fumaroles, intermittently active thermal springs, and associated altered rocks occur within and immediately east of the central part of the field of Quaternary rhyolite, in an area characterized by various geophysical anomalies that are evidently related to an active hot-water geothermal system. This system apparently is heated by a reservoir of silicic magma at > or =8-km depth, itself produced and sustained through partial melting of crustal rocks by thermal energy contained in mantle-derived basaltic magma that intrudes the crust in repsonse to lithospheric extension.

  10. Which downscaled rainfall data for climate change impact studies in urban areas? Review of current approaches and trends

    Science.gov (United States)

    Gooré Bi, Eustache; Gachon, Philippe; Vrac, Mathieu; Monette, Frédéric

    2015-10-01

    Changes in extreme precipitation should be one of the primary impacts of climate change (CC) in urban areas. To assess these impacts, rainfall data from climate models are commonly used. The main goal of this paper is to report on the state of knowledge and recent works on the study of CC impacts with a focus on urban areas, in order to produce an integrated review of various approaches to which future studies can then be compared or constructed. Model output statistics (MOS) methods are increasingly used in the literature to study the impacts of CC in urban settings. A review of previous works highlights the non-stationarity nature of future climate data, underscoring the need to revise urban drainage system design criteria. A comparison of these studies is made difficult, however, by the numerous sources of uncertainty arising from a plethora of assumptions, scenarios, and modeling options. All the methods used do, however, predict increased extreme precipitation in the future, suggesting potential risks of combined sewer overflow frequencies, flooding, and back-up in existing sewer systems in urban areas. Future studies must quantify more accurately the different sources of uncertainty by improving downscaling and correction methods. New research is necessary to improve the data validation process, an aspect that is seldom reported in the literature. Finally, the potential application of non-stationarity conditions into generalized extreme value (GEV) distribution should be assessed more closely, which will require close collaboration between engineers, hydrologists, statisticians, and climatologists, thus contributing to the ongoing reflection on this issue of social concern.

  11. Variability and climate change trend in vegetation phenology of recent decades in the Greater Khingan Mountain area, Northeastern China

    Directory of Open Access Journals (Sweden)

    Huan Tang

    2015-09-01

    Full Text Available Vegetation phenology has been used in studies as an indicator of an ecosystem’s responses to climate change. Satellite remote sensing techniques can capture changes in vegetation greenness, which can be used to estimate vegetation phenology. In this study, a long-term vegetation phenology study of the Greater Khingan Mountain area in Northeastern China was performed by using the Global Inventory Modeling and Mapping Studies (GIMMS normalized difference vegetation index version 3 (NDVI3g dataset from the years 1982–2012. After reconstructing the NDVI time series, the start date of the growing season (SOS, the end date of the growing season (EOS and the length of the growing season (LOS were extracted using a dynamic threshold method. The response of the variation in phenology with climatic factors was also analyzed. The results showed that the phenology in the study area changed significantly in the three decades between 1982 and 2012, including a 12.1-day increase in the entire region’s average LOS, a 3.3-day advance in the SOS and an 8.8-day delay in the EOS. However, differences existed between the steppe, forest and agricultural regions, with the LOSs of the steppe region, forest region and agricultural region increasing by 4.40 days, 10.42 days and 1.71 days, respectively, and a later EOS seemed to more strongly affect the extension of the growing season. Additionally, temperature and precipitation were closely correlated with the phenology variations. This study provides a useful understanding of the recent change in phenology and its variability in this high-latitude study area, and this study also details the responses of several ecosystems to climate change.

  12. Modelling global water stress of the recent past: on the relative importance of trends in water demand and climate variability

    Science.gov (United States)

    Wada, Y.; van Beek, L. P. H.; Bierkens, M. F. P.

    2011-12-01

    During the past decades, human water use has more than doubled, yet available freshwater resources are finite. As a result, water scarcity has been prevalent in various regions of the world. Here, we present the first global assessment of past development of water stress considering not only climate variability but also growing water demand, desalinated water use and non-renewable groundwater abstraction over the period 1960-2001 at a spatial resolution of 0.5°. Agricultural water demand is estimated based on past extents of irrigated areas and livestock densities. We approximate past economic development based on GDP, energy and household consumption and electricity production, which are subsequently used together with population numbers to estimate industrial and domestic water demand. Climate variability is expressed by simulated blue water availability defined by freshwater in rivers, lakes, wetlands and reservoirs by means of the global hydrological model PCR-GLOBWB. We thus define blue water stress by comparing blue water availability with corresponding net total blue water demand by means of the commonly used, Water Scarcity Index. The results show a drastic increase in the global population living under water-stressed conditions (i.e. moderate to high water stress) due to growing water demand, primarily for irrigation, which has more than doubled from 1708/818 to 3708/1832 km3 yr-1 (gross/net) over the period 1960-2000. We estimate that 800 million people or 27% of the global population were living under water-stressed conditions for 1960. This number is eventually increased to 2.6 billion or 43% for 2000. Our results indicate that increased water demand is a decisive factor for heightened water stress in various regions such as India and North China, enhancing the intensity of water stress up to 200%, while climate variability is often a main determinant of extreme events. However, our results also suggest that in several emerging and developing economies

  13. Modelling global water stress of the recent past: on the relative importance of trends in water demand and climate variability

    Directory of Open Access Journals (Sweden)

    Y. Wada

    2011-08-01

    Full Text Available During the past decades, human water use more than doubled, yet available freshwater resources are finite. As a result, water scarcity has been prevalent in various regions of the world. Here, we present the first global assessment of past development of water scarcity considering not only climate variability but also growing water demand, desalinated water use and non-renewable groundwater abstraction over the period 1960–2001 at a spatial resolution of 0.5°. Agricultural water demand is estimated based on past extents of irrigated areas and livestock densities. We approximate past economic development based on GDP, energy and household consumption and electricity production, which is subsequently used together with population numbers to estimate industrial and domestic water demand. Climate variability is expressed by simulated blue water availability defined by freshwater in rivers, lakes and reservoirs by means of the global hydrological model PCR-GLOBWB. The results show a drastic increase in the global population living under water-stressed conditions (i.e., moderate to high water stress due to the growing water demand, primarily for irrigation, which more than doubled from 1708/818 to 3708/1832 km3 yr−1 (gross/net over the period 1960–2000. We estimate that 800 million people or 27 % of the global population were under water-stressed conditions for 1960. This number increased to 2.6 billion or 43 % for 2000. Our results indicate that increased water demand is the decisive factor for the heightened water stress, enhancing the intensity of water stress up to 200 %, while climate variability is often the main determinant of onsets for extreme events, i.e. major droughts. However, our results also suggest that in several emerging and developing economies (e.g., India, Turkey, Romania and Cuba some of the past observed droughts were anthropogenically driven due to increased water demand rather than being climate

  14. Means, Variability and Trends of Precipitation in the Global Climate as Determined by the 25-year GEWEWGPCP Data Set

    Science.gov (United States)

    Adler, R. F.; Gu, G.; Curtis, S.; Huffman, G. J.

    2004-01-01

    The Global Precipitation Climatology Project (GPCP) 25-year precipitation data set is used as a basis to evaluate the mean state, variability and trends (or inter-decadal changes) of global and regional scales of precipitation. The uncertainties of these characteristics of the data set are evaluated by examination of other, parallel data sets and examination of shorter periods with higher quality data (e.g., TRMM). The global and regional means are assessed for uncertainty by comparing with other satellite and gauge data sets, both globally and regionally. The GPCP global mean of 2.6 mdday is divided into values of ocean and land and major latitude bands (Tropics, mid-latitudes, etc.). Seasonal variations globally and by region are shown and uncertainties estimated. The variability of precipitation year-to-year is shown to be related to ENS0 variations and volcanoes and is evaluated in relation to the overall lack of a significant global trend. The GPCP data set necessarily has a heterogeneous time series of input data sources, so part of the assessment described above is to test the initial results for potential influence by major data boundaries in the record.

  15. Late Cenozoic stress field distribution in Biga Peninsula, NW Turkey

    Science.gov (United States)

    Ozden, S.; Bekler, T.; Tutkun, S. Z.; Kurcer, A.; Ates, O.; Bekler, F. N.; Kalafat, D.

    2009-04-01

    Biga Peninsula is a seismically active region both in instrumental and historical period in NW Turkey. In this part, middle and southern branches of North Anatolian Fault are represented by Etili, Can-Biga, Yenice-Gonen, Manyas-Danisment, Lapseki, Sinekci, Terzialan, Dogruca, Uluabat, Edincik, Pazarkoy-Hamdibey-Kalkim, Edremit, Yigitler, Sarikoy-Inova, Troia and Karabiga Faults. All of these faults are responsible of the seismic activity in Biga Peninsula. Historical earthquakes happened in 29, 155, 170, 543, 620, 1440, 1737, 1855, 1865 and 1875. Furthermore, as for instrumental period, Saros Gulf-Murefte earthquakes (M:7.3 and M:6.3) in 1912, Erdek Gulf (M:6.4) and Can-Biga (M:6.3) in 1935, Edremit Gulf-Ayvaci k (M:6.8) in 1944, Yenice-Gonen (M:7.2) in 1953, Gonen (M:5.8) in 1964, Edremit-Baki rcay (M:5.5) in 1971, Biga (M:5.8) in 1983, Kusgolu-Manyas (M:5.2) and Bandirma (M:5.0) in 2006. In this study, we determined the Late Cenozoic stress field distribution and present-day tectonic regimes both fault-slip data (by 253 fault planes) and earthquake focal mechanism solutions (by 58 earthquakes) were investigated by the inversion methods. The results indicate that a transtensional stress regime is dominant with a NW-SE to WNW-ESE directed compression (1) and NE-SW to ENE-WSW directed extension (3), which yielded a NE-SW, ENE-WSW and also E-W trending strike-slip faulting faults with a normal component. While a transtensional tectonic regime has an active component in Biga Peninsula, a local and consistent transpressional tectonic regime were determined along an E-W trending narrow zone in the northern part of the Biga Peninsula also. The tectonic regime and stress field is resulted from interactions both continental collision of Eurasian/Anatolian/Arabian plate in the east and subduction processes (roll back and/or slab-pull) of the African plate along the Cyprus and Hellenic arc in the Mediterranean region.

  16. CENOZOIC VOLCANISM AND GEOTHERMAL RESOURCES IN NORTHEAST CHINA

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper is concentrated on Cenozoic volcanism and geothermal resources in Northeast China. There are a lot of Cenozoic volcanoes, a large area of volcanic rocks, a large number of active faults and rich geothermal resources in Northeast China. The time and space characteristics of Cenozoic volcanism and the space distribution characters of hot springs and high geothermal flux regions in Northeast China are described and discussed on the basis of geological, geothermal, drilling and volcanological data. It is revealed that the hot springs and high geothermal flux regions are re lated to the Cenozoic volcanism, rifting and faulting in Northeast China. It is especially emphasized that the hot springs and high geothermal anomaly areas are controlled by active deep faults. It is proposed that the Cenozoic volcanism re gions, rift basins, active fault belts, activated plate suture zones and large earthquake occurrence points are the best areas for prospecting geothermal resources. The geothermal resources in younger volcanic zones are richer than those in older volcanic belts. The hot springs and active or activated faults might be a very good clue for looking for geothermal resources.

  17. New findings on increasing solar trend that can change Earth climate: are we entering new great solar minima?

    Science.gov (United States)

    Rozelot, J. P.

    2009-10-01

    Studies of the Sun-Earth relationships during the past years have dramatically changed our view on Solar- Terrestrial Physics. Neither is the interplanetary medium unstructured or quasi-static, nor is it a simple magnetic stratified object. Thus, the interaction of the solar electromagnetic radiation (photons), hot plasma (electrons, protons and other ions), cosmic rays, microscopic dust particles, and magnetic fields (primarily from the Sun) with the upper environment of our Earth leads to a complex physics which is far to be understandable. This new science is growing rapidly, as well as for the physical problems which arise as for its growing impact on our societies. This last case is well illustrated by the emergence of the so-called Space Weather. In spite of a great number of papers and books written on this subject and on a broader one devoted to Solar-Terrestrial links, the different terms deserve to be clarified. In this paper, we will first establish a clear distinction between Space Weather, Space Climate, Space Physics, Sun-Earth connections, and Helioclimatology, this last word being introduced to describe the role of the Sun in the Earth's climate forcing. In a second step, we will emphasize the key role of the ranging time on which the effects may act. We will then underline the necessity to better predict solar activity showing the physical difficulties for such an exercise, yielding the extreme complexity for forecasting specific events. The three dataset, past Earth's temperature (since AD 630), solar shape variability (since AD 1600) and strength of umbral/sunspots magnetic field (since AD 1995) lead all to a Next Grand Minima predictable for 2015-2018. We will conclude by giving some imprints for the future.

  18. Continental-scale assessment of long-term trends in wet deposition trajectories: Role of anthropogenic and hydro-climatic drivers

    Science.gov (United States)

    Park, J.; Gall, H. E.; Niyogi, D.; Rao, S.

    2012-12-01

    The global trend of increased urbanization, and associated increased intensity of energy and material consumption and waste emissions, has contributed to shifts in the trajectories of aquatic, terrestrial, and atmospheric environments. Here, we focus on continental-scale spatiotemporal patterns in two atmospheric constituents (nitrate and sulfate), whose global biogeochemical cycles have been dramatically altered by emissions from mobile and fixed sources in urbanized and industrialized regions. The observed patterns in wet deposition fluxes of nitrate and sulfate are controlled by (1) natural hydro-climatic forcing, and (2) anthropogenic forcing (emissions and regulatory control), both of which are characterized by stochasticity and non-stationarity. We examine long-term wet deposition records in the U.S., Europe, and East Asia to evaluate how anthropogenic and natural forcing factors jointly contributed to the shifting temporal patterns of wet deposition fluxes at continental scales. These data offer clear evidence for successful implementation of regulatory controls and widespread adoption of technologies contributed to improving water quality and mitigation of adverse ecological impacts. We developed a stochastic model to project the future trajectories of wet deposition fluxes in emerging countries with fast growing urban areas. The model generates ellipses within which projected wet deposition flux trajectories are inscribed, similar to the trends in observational data. The shape of the ellipses provides information regarding the relative dominance of anthropogenic (e.g., industrial and urban emissions) versus hydro-climatic drivers (e.g., rainfall patterns, aridity index). Our analysis facilitates projections of the trajectory shift as a result of urbanization and other land-use changes, climate change, and regulatory enforcement. We use these observed data and the model to project likely trajectories for rapidly developing countries (BRIC), with a

  19. Relating Cenozoic North Sea sediments to topography in southern Norway:

    DEFF Research Database (Denmark)

    Anell, Ingrid Anna Margareta; Thybo, Hans; Stratford, Wanda Rose

    2010-01-01

    sources for progradational influx of clastic sediments from Scotland, the Shetland platform and, to a lesser degree, southwestern Norway. The Eocene sedimentation pattern was similar to the Palaeocene, with lower rates of accumulation associated with flooding and tectonic quiescence. Sediment influx from...... the Shetland platform continued throughout the Cenozoic while supply from southern Norway increased markedly around the Eocene–Oligocene, coeval with the greenhouse–icehouse transition. Mass balance calculations of sediment and eroded rock volumes suggest that while some topography along the western...... margin of Norway may be pre-Cenozoic, significant uplift of the main Paleic surface in southern Norway occurred around the early Oligocene. Sedimentation rates were almost ten-fold higher than the Cenozoic average in the Plio-Pleistocene, slightly higher than the global average. Mass balance calculations...

  20. Trends in greenhouse gas emissions from consumption and production of animal food products - implications for long-term climate targets.

    Science.gov (United States)

    Cederberg, C; Hedenus, F; Wirsenius, S; Sonesson, U

    2013-02-01

    To analyse trends in greenhouse gas (GHG) emissions from production and consumption of animal products in Sweden, life cycle emissions were calculated for the average production of pork, chicken meat, beef, dairy and eggs in 1990 and 2005. The calculated average emissions were used together with food consumption statistics and literature data on imported products to estimate trends in per capita emissions from animal food consumption. Total life cycle emissions from the Swedish livestock production were around 8.5 Mt carbon dioxide equivalents (CO2e) in 1990 and emissions decreased to 7.3 Mt CO2e in 2005 (14% reduction). Around two-thirds of the emission cut was explained by more efficient production (less GHG emission per product unit) and one-third was due to a reduced animal production. The average GHG emissions per product unit until the farm-gate were reduced by 20% for dairy, 15% for pork and 23% for chicken meat, unchanged for eggs and increased by 10% for beef. A larger share of the average beef was produced from suckler cows in cow-calf systems in 2005 due to the decreasing dairy cow herd, which explains the increased emissions for the average beef in 2005. The overall emission cuts from the livestock sector were a result of several measures taken in farm production, for example increased milk yield per cow, lowered use of synthetic nitrogen fertilisers in grasslands, reduced losses of ammonia from manure and a switch to biofuels for heating in chicken houses. In contrast to production, total GHG emissions from the Swedish consumption of animal products increased by around 22% between 1990 and 2005. This was explained by strong growth in meat consumption based mainly on imports, where growth in beef consumption especially was responsible for most emission increase over the 15-year period. Swedish GHG emissions caused by consumption of animal products reached around 1.1 t CO2e per capita in 2005. The emission cuts necessary for meeting a global temperature

  1. Microbial Contamination Detection in Water Resources: Interest of Current Optical Methods, Trends and Needs in the Context of Climate Change

    Directory of Open Access Journals (Sweden)

    Aude-Valérie Jung

    2014-04-01

    Full Text Available Microbial pollution in aquatic environments is one of the crucial issues with regard to the sanitary state of water bodies used for drinking water supply, recreational activities and harvesting seafood due to a potential contamination by pathogenic bacteria, protozoa or viruses. To address this risk, microbial contamination monitoring is usually assessed by turbidity measurements performed at drinking water plants. Some recent studies have shown significant correlations of microbial contamination with the risk of endemic gastroenteresis. However the relevance of turbidimetry may be limited since the presence of colloids in water creates interferences with the nephelometric response. Thus there is a need for a more relevant, simple and fast indicator for microbial contamination detection in water, especially in the perspective of climate change with the increase of heavy rainfall events. This review focuses on the one hand on sources, fate and behavior of microorganisms in water and factors influencing pathogens’ presence, transportation and mobilization, and on the second hand, on the existing optical methods used for monitoring microbiological risks. Finally, this paper proposes new ways of research.

  2. Understanding Climate Change on the California Coast: Accounting for Extreme Daily Events among Long-Term Trends

    Directory of Open Access Journals (Sweden)

    Christopher Potter

    2014-02-01

    Full Text Available The majority of weather station records indicate that surface air temperatures have been warming in California between 1950 and 2005. Temperature data from the mid-1990s to the present were analyzed for stations on California Central Coast near Big Sur (Monterey County to better understand potential for climate change in this biologically unique region. Results showed that daily temperatures in both the winter and summer seasons have cooled the Big Sur coast, particularly after 2003. A current hypothesis is that observed coastal California cooling derives from greenhouse gas-induced regional warming of the inland Central Valley and Sierra Nevada foothill areas, resulting in stronger sustained on-shore sea-breeze flow. Closer examination of daily temperature records at a station location near the Big Sur coast revealed that, even as average monthly maximum temperatures (Tmax have decreased gradually, the number of extreme warm summer days (Tmax > 37 °C has also increased by several fold in frequency. Overall patterns in the station records since the mid-1990s indicated that diurnal temperature ranges are widening on the Big Sur coast, with markedly cooler nighttime temperatures (frequently in the wet winter season followed by slightly higher-than-average daytime temperatures, especially during the warm, dry summer season.

  3. Assessing rainfall trends and remote drivers in regional climate change projections: The demanding test case of Tasmania

    International Nuclear Information System (INIS)

    Understanding and modelling Tasmanian rainfall variability and making future projections of Tasmanian rainfall are challenging tasks. Tasmania has spatially and temporally complex rainfall patterns. Rainfall variability is influenced by a complex suite of remote drivers and these influences vary by season. The Climate Futures for Tasmania high-resolution model simulations project small changes to annual rainfall averaged over Tasmania, but larger changes to the spatial patterns and seasonality of rainfall. A case study of changes to summer rainfall under a high greenhouse gas emission scenario is shown here. The projected summer decrease in rainfall in the western rainfall region is consistent with the southerly movement and intensification of the subtropical ridge as well as an enhancement of the high phase of the Southern Annular Mode. The increase along the east coastal strip is consistent with an increase in blocking in the Tasman Sea as well as an increase in sea surface temperature, relative humidity and convective rainfall. We propose that projections of rainfall for places like Tasmania are strengthened through dynamical downscaling and also the analysis of the rainfall mechanisms within the model at all length scales.

  4. From Arctic greenhouse to icehouse: the Cenozoic development of the West Greenland-Baffin Bay margin and the case for scientific drilling

    Science.gov (United States)

    Knutz, Paul; Gregersen, Ulrik; Hopper, John R.; Dybkjær, Karen; Nøhr-Hansen, Henrik; Sheldon, Emma; Huuse, Mads

    2016-04-01

    The long-term evolution of glaciated margins plays an essential role in understanding the driving forces and interactions that determine the build-up and decay of ice sheets. The Greenland continental margin towards Baffin Bay is densely covered by industry seismic data and several exploration wells have been drilled, providing a regional stratigraphic framework for the sedimentary successions. This presentation provides an overview of the major depositional units and stratigraphy of the mid-late Cenozoic (since mid-Eocene), with examples demonstrating the different processes that have formed this margin. A sedimentary succession up to 3.5 km thick, of mid-Eocene to mid-Miocene age (mega-unit D), infills the pronounced ridge-basin structures of the rifted and tectonically inverted margin. The lower part of this interval, presumably late Eocene-Oligocene in age, is interpreted as basin-floor fan deposits, while the upper section, of early-middle Miocene age, is mainly marine mudstone. The basin infilling strata are overlain by a late Miocene-Pliocene succession consisting of two mega-units (B and C), with typical thicknesses of 0.5-1 km. The units are characterised by upslope-climbing sediment waves and along-slope trending sedimentary prisms reminiscent of giant contourite drifts. The borehole data associates the prism accumulations with a deep shelf environment influenced by strong marine currents and nearby fluvial sources. On the slope and in the deep basin of Baffin Bay the late Neogene succession is strongly influenced by mass wasting correlated with erosional scars updip. The uppermost seismic mega-unit (A) is dominated by aggradational wedges and prograding fan deposits displaying depocentres >3 km thick, formed at the terminus of palaeo-ice streams. Borehole information associates this interval with deposition of primarily diamict sediments and suggests a late Pliocene onset of major shelf based glaciations on the NW Greenland margin. The southwest margin

  5. Cenozoic extensional tectonics of the Western Anatolia Extended Terrane, Turkey

    International Nuclear Information System (INIS)

    The Western Anatolia Extended Terrane in Turkey is located on the eastern side of the Aegean Extended Terrane and contains one of the largest metamorphic core complexes in the world, the Menderes massif. It has experienced a series of continental collisions from the Late Cretaceous to the Eocene during the formation of the Izmir-Ankara-Erzincan suture zone. Based our field work and monazite ages, we suggest that the north-directed postcollisional Cenozoic extension in the region is the product of three consecutive stages, triggered by three different mechanisms. The first stage was initiated about 30 Ma ago, in the Oligocene by the Orogenic Collapse the thermally weakened continental crust along the north-dipping Southwest Anatolian shear zone. The shear zone was formed as an extensional simple-shear zone with listric geometry at depth and exhibits predominantly normal-slip along its southwestern end. But, it becomes a high-angle oblique-slip shear zone along its northeastern termination. Evidence for the presence of the shear zone includes (1) the dominant top to the north-northeast shear sense indicators throughout the Menderes massif, such as stretching lineations trending N10E to N30E; and (2) a series of Oligocene extensional basins located adjacent to the shear zone that contain only carbonate and ophiolitic rock fragments, but no high grade metamorphic rock fragments. During this stage, erosion and extensional unroofing brought high-grade metamorphic rocks of the Central Menderes massif to the surface by the early Miocene. The second stage of the extension was triggered by subduction roll-back and associated back-arc extension in the early Miocene and produced the north-dipping Alasehir and the south-dipping Bueyuek Menderes detachments of the central Menderes massif and the north-dipping Simav detachment of the northern Menderes massif. The detachments control the Miocene sedimentation in the Alasehir, Bueyuek Menderes, and Simav grabens, containing high

  6. Implications for climate change policy of trends in exports and imports of energy commodities and manufactured goods

    International Nuclear Information System (INIS)

    A number of formal and informal policy processes are underway to explore the issue of 'where to next' for the international climate change regime post-2012. Currently these are informed by data based mainly on production statistics only. A key purpose of this study and report is to raise issues associated with trade in energy commodities and manufactured goods, in order to ensure that important perspectives which can be discerned from considering this 'consumption side' are not overlooked. A number of previous studies and papers have explored issues regarding embodied greenhouse gas emissions in traded energy commodities and manufactured goods. This study draws out key messages from these. It also expands on the existing literature by covering some non-CO2 greenhouse gas emissions, and also by considering traded renewables-based commodities. This work is not intended to be a comprehensive resource of quantitative data. Rather, examples of data are selected to help articulate and elaborate key issues. Section 2 describes the nature of the data sets that have been researched and utilised in developing any quantitative results. It outlines some relevant limitations of the methodologies underlying these data sets, and the nature of uncertainties. It also describes the methodology used in this work to unpack and/or re-present data. Section 3 provides data and analysis addressing the key objective noted above, i.e. to identify 'significant instances where transferred benefits and avoided costs occur - and the extent to which the exporter is likely to be compensated in the absence of policies intended for this purpose'. Section 4 draws out some of the key policy-relevant 'messages' and issues from this data. It uses a number of example cases to help do this, in a manner that is intended to be thought provoking, but not judgemental or prejudicial. Appendix A lists the existing literature that has informed this report. Appendix B reproduces a paper written on a subject that

  7. Paleoenvironmental reconstruction of the late Cenozoic Qaidam Basin, China

    Science.gov (United States)

    Zhang, C.; Wang, Y.; Li, Q.; Wang, X.; Deng, T.; Tseng, Z. J.; Takeuchi, G.; Xie, G.; Xu, Y.

    2011-12-01

    Reconstruction of paleoenvironments in the Tibetan region is important to understanding the linkage between tectonic force and climate change. Here we report new isotope data from the Qaidam Basin, China, which is located on the northeastern Tibetan Plateau, including stable C and O isotope analyses of a wide variety of late Cenozoic mammalian tooth enamel samples (including deer, giraffe, horse, rhino, and elephant), and O isotope compositions of phosphate (δ18Op) in fish bone samples. Mammalian tooth enamel δ13C values, when combined with fossil assemblage and other geological evidence, indicate that the Qaidam Basin was warmer and more humid during the late Miocene and early Pliocene, and that there was lush C3 vegetation with significant C4 components at that time, although the C4 plants were not consistently utilized. In contrast, the modern Qaidam Basin is dominated by C3 plants. Fish bone δ18Op values showed statistically significant enrichment from the Tuxi-Shengou-Naoge interval (late Miocene) to the Yahu interval (early Pliocene) and from the Yahu interval to the present day. This most likely reflects increases in the δ18O of lake water over time, as a result of increased aridification of the Qaidam Basin. Assuming that mammals drank exclusively from the lake, temperatures were calculated from average δ18Op values and average δ18Ow derived from large mammal tooth enamel δ18O. Temperatures were also estimated from δ18Op and δ18Ow estimated from co-ocurring large mammal tooth enamel δ18O. The temperature estimates were all lower than the average temperature of the modern Qinghai Lake surface water during the summer, and mostly too low to be reasonable, indicating that the fish and the large mammals were not in equilibrium with the same water. Assuming the relationship between salinity and δ18Ow observed for the modern Qinghai Lake and its surrounding lakes and ponds applied in the past, we calculated the paleosalinities of lake waters to be ~0 to

  8. Meso-Cenozoic basin evolution in northern Korean Peninsula

    Institute of Scientific and Technical Information of China (English)

    PAK Hyon Uk; LYANG To Jun; LIU Yongjiang; HYON Yun Su; KIM Gyong Chol

    2009-01-01

    In the Korean Peninsula the Meso-Cenozoic basins were mainly formed due to fault block and block movement. The Mesozoic fracture structures correspond basically to modern large rivers in direction. Such faults were usually developed to rift and formed lake-type tectonic basin, such as the Amrokgang-, Taedonggang-, Ryesonggang-, Hochongang-, Jangphari-, Susongchon-, Pujon-, and Nampho basins. The Mesozoic strata are considered to be divided into the Lower Jurassic Taedong System, Upper Jurassic Jasong System, Upper Jurassic- -early Lower Cretaceous Taebo System, and the Upper Cretaceous- -Paleocene (Chonjaebong, Hongwon, Jaedok Series). The Cenozoic block movement succeeded the Mesozoic fault block movement. The Kilju-Myongchon Graben and Tumangang Basin, etc, are the basins related to the fault zones developed from the Oligocene to Miocene. In addition, the Tertiary basins were formed in many areas in the Miocene (e.g. Sinhung, Oro, Hamhung, Yonghung, Anbyon, Cholwon, etc). The Cenozoic sedimentation occurred mainly from the late Oligocene to Miocene. The Kilju-Myongchon Graben was the fore deep connected to the sea and the basins inclined in the Chugaryong Fault Zone are intramountain basins. Therefore, coal-bearing beds and clastic rocks in the intramountain basins and rare marine strata and terrigenous clastic rocks are main sedimentary sequences in the Cenozoic.

  9. Paleomagnetic results from Cenozoic volcanics of Lusatia, NW Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Schnabl, Petr; Cajz, Vladimír; Tietz, O.; Buechner, J.; Suhr, P.; Pécskay, Z.; Čížková, Kristýna

    s. l: American Geophysical Union, 2013. [AGU Meeting of the Americas. 14.05.2013-17.05.2013, Cancun] Institutional support: RVO:67985831 Keywords : paleomagnetism * Cenozoic * volcanics Subject RIV: DE - Earth Magnetism, Geodesy, Geography http://moa.agu.org/2013/eposters/eposter/gp33a-03/

  10. Cenozoic plant diversity in the neotropics.

    Science.gov (United States)

    Jaramillo, Carlos; Rueda, Milton J; Mora, Germán

    2006-03-31

    Several mechanisms have been proposed to explain the high levels of plant diversity in the Neotropics today, but little is known about diversification patterns of Neotropical floras through geological time. Here, we present the longest time series compiled for palynological plant diversity of the Neotropics (15 stratigraphic sections, 1530 samples, 1411 morphospecies, and 287,736 occurrences) from the Paleocene to the early Miocene (65 to 20 million years ago) in central Colombia and western Venezuela. The record shows a low-diversity Paleocene flora, a significantly more diverse early to middle Eocene flora exceeding Holocene levels, and a decline in diversity at the end of the Eocene and early Oligocene. A good correlation between diversity fluctuations and changes in global temperature was found, suggesting that tropical climate change may be directly driving the observed diversity pattern. Alternatively, the good correspondence may result from the control that climate exerts on the area available for tropical plants to grow. PMID:16574860

  11. Glacier response to changing climate condition : the role of circulation variability and long-term trends over the Tibetan Plateau, China

    Energy Technology Data Exchange (ETDEWEB)

    Caidong, C.

    2008-07-01

    This study focuses on glacier response to changing climatic condition, the role of atmospheric circulation variability and long-term trends over the Tibetan Plateau (TP). In particular, this study concerns circulation regimes over the TP and related precipitation and temperature variations in Tibet Autonomous Region; modelled mass balance response of the Xibu glacier (which is situated in the Nyainqentanglha mountain range) to the circulation variability and the mass balance response to long term trends that is not directly related to circulation variability. The research was motivated by the importance of understanding present-day climate condition over the Tibetan Plateau and to understand how much of last decade's increases in temperature and glacier retreat could be linked to circulation changes and how much was due to other causes. The first paper, the focus is on using the six years of the Tropical Rainfall Monitoring Mission (TRMM) satellite data (1998 - 2005) to identify the spatial pattern of the dry season (October - April) precipitation over the TP which is small, but important for snow accumulation over the plateau. The paper outline the use of k-mean clustering as a method for finding different weather types and the precipitation variability is tried explained with physical interpretation of the associated atmospheric circulation patterns using daily reanalysis from NCEP/NCAR (1957 - 2005). The results show how the topographic effect and flow direction plays an important role in controlling the distribution of precipitation rates over the plateau. The Himalayas and Karakorum Mountain ranges act as barriers for south and south-west moist air flow and deplete the air of much of its moisture before it reaches the Plateau. In addition, when the air begin to descend on the leeward side of the mountains, they are creating a rain shadow. According to the TRMM satellite estimates average October-April Tibetan Plateau (defined as areas higher than 4,000 m

  12. Future climate trends from a first-difference atmospheric carbon dioxide regression model involving emissions scenarios for business as usual and for peak fossil fuel

    CERN Document Server

    Leggett, L M W

    2014-01-01

    This paper investigates the implications of the future continuation of the demonstrated past (1960-2012) strong correlation between first-difference atmospheric CO2 and global surface temperature. It does this, for the period from the present to 2050, for a comprehensive range of future global fossil fuel energy use scenarios. The results show that even for a business-as-usual (the mid-level IPCC) fossil fuel use estimate, global surface temperature will rise at a slower rate than for the recent period 1960-2000. Concerning peak fossil fuel, for the most common scenario the currently observed (1998-2013)temperature plateau will turn into a decrease. The observed trend to date for temperature is compared with that for global climate disasters: these peaked in 2005 and are notably decreasing. The temperature and disaster results taken together are consistent with either a reduced business-as-usual fossil fuel use scenario into the future, or a peak fossil fuel scenario, but not with the standard business-as-usu...

  13. Long-term variations and trends in the simulation of the middle atmosphere 1980–2004 by the chemistry-climate model of the Meteorological Research Institute

    Directory of Open Access Journals (Sweden)

    M. Deushi

    2008-05-01

    Full Text Available A middle-atmosphere simulation of the past 25 years (from 1980 to 2004 has been performed with a chemistry-climate model (CCM of the Meteorological Research Institute (MRI under observed forcings of sea-surface temperature, greenhouse gases, halogens, volcanic aerosols, and solar irradiance variations. The dynamics module of MRI-CCM is a spectral global model truncated triangularly at a maximum wavenumber of 42 with 68 layers extending from the surface to 0.01 hPa (about 80 km, wherein the vertical spacing is 500 m from 100 to 10 hPa. The chemistry-transport module treats 51 species with 124 reactions including heterogeneous reactions. Transport of chemical species is based on a hybrid semi-Lagrangian scheme, which is a flux form in the vertical direction and an ordinary semi-Lagrangian form in the horizontal direction. The MRI-CCM used in this study reproduced a quasi-biennial oscillation (QBO of about a 20-month period for wind and ozone in the equatorial stratosphere. Multiple linear regression analysis with time lags for volcanic aerosols was performed on the zonal-mean quantities of the simulated result to separate the trend, the QBO, the El Chichón and Mount Pinatubo, the 11-year solar cycle, and the El Niño/Southern Oscillation (ENSO signals. It is found that MRI-CCM can more or less realistically reproduce observed trends of annual mean temperature and ozone, and those of total ozone in each month. MRI-CCM also reproduced the vertical multi-cell structures of tropical temperature, zonal-wind, and ozone associated with the QBO, and the mid-latitude total ozone QBO in each winter hemisphere. Solar irradiance variations of the 11-year cycle were found to affect radiation alone (not photodissociation because of an error in making the photolysis lookup table. Nevertheless, though the heights of the maximum temperature (ozone in the tropics are much higher (lower than observations, MRI-CCM could reproduce the second maxima of temperature and

  14. Climate science: Breaks in trends

    Science.gov (United States)

    Pretis, Felix; Allen, Myles

    2013-12-01

    Global temperature rise since industrialization has not been uniform. A statistical analysis suggests that past changes in the rate of warming can be directly attributed to human influences, from economic downturns to the regulations of the Montreal Protocol.

  15. Streamflow trends and hydrological response to climatic change in Tarim headwater basin%塔里木河流域径流变化趋势及其对气候变化的响应

    Institute of Scientific and Technical Information of China (English)

    蒋艳; 周成虎; 程维明

    2007-01-01

    This paper has studied the change of streamflow and the impact of climatic variability conditions on regional hydrological cycle in the headwater of the Tarim River Basin.This study investigates possible causes of observed trends in streamflow in an environment which is highly variable in terms of atmospheric conditions, and where snow and ice melt play an important role in the natural hydrological regime. The discharge trends of three head streams have a significant increase trend from 1957 to 2002 with the Mann-Kendall test.Complex time-frequency distributions in the streamflow regime are demonstrated especially by Morlet wavelet analysis over 40 years. The purpose is to ascertain the nature of climatic factors spatial and temporal distribution, involved the use of EOF (Empirical Orthogonal Function) to compare the dominant temperature, precipitation and evaporation patterns from normally climatic records over the Tarim's headwater basin. It shows that the first principal component was dominated since the 1990s for temperature and precipitation, which identifies the significant ascending trend of spatial and temporal pattern characteristics under the condition of the global warming. An exponential correlation is highlighted between surface air temperature and mean river discharge monthly, so the regional runoff increases by 10%-16% when surface air temperature rises by 1 ℃. Results suggest that headwater basins are the most vulnerable environments from the point of view of climate change, because their watershed properties promote runoff feeding by glacier and snow melt water and their fundamental vulnerability to temperature changes affects rainfall, snowfall, and glacier and ice melt.

  16. Cenozoic Uplift, Erosion and Dynamic Support of Madagascar

    Science.gov (United States)

    Stephenson, Simon; White, Nicky

    2016-04-01

    The physiography of Madagascar is characterised by high-elevation but low-relief topography; 42% of the landscape is above 500 m in elevation. Eocene (marine) nummulitic (marine) limestones at elevations of ˜400 m above sea level and newly dated, emergent 125 ka coral reefs suggest that Madagascar has experienced differential vertical motions during Cenozoic times. Malagasy rivers are often deeply incised and contain steepened reaches, implying that they have responded to changes in regional uplift rate. However, low temperature thermochronology and 10Be derived erosion rates suggest that both Cenozoic and Recent average denudation rates have been low. Extensive laterite-capped, low-relief surfaces also suggest that there have been long periods of tectonic quiescence. In contrast, the modern landscape is characterised by erosional gullies (i.e. lavaka), with very high local erosion rates. To bridge the gap between this disparate evidence, we inverted 2566 longitudinal river profiles using a damped non-negative, least-squares linear inversion to determine the history of regional uplift. We used a simplified version of the stream power erosional law. River profiles were extracted from the 3 arc-second Shuttle Radar Topography Mission (SRTM) digital elevation model. Calibration of the stream power erosional law is based upon Cenozoic limestones and new radiometrically dated marine terraces. The residual misfit between observed and calculated river profiles is small. Results suggest that Malagasy topography grew diachronously by 1-2 km over the last 15-20 Ma. Calculated uplift and denudation are consistent with independent observations. Thus drainage networks contain coherent signals that record regional uplift. The resultant waves of incision are the principal trigger for modern erosional processes. Admittance calculations, the history of basaltic volcanism and nearby oceanic residual age-depth measurements all suggest that as much as 0.8 - 1.1 km of Cenozoic uplift

  17. The Cenozoic Tectonic History of the Calabrian Orogen, Southern Italy

    OpenAIRE

    Shimabukuro, David Haruo

    2011-01-01

    The Cenozoic accretionary wedge of Calabria, Southern Italy, consists of several units of continental and oceanic affinity accreted beneath the former continental margin of the Sardinia-Corsica block. Each of these units bears the imprint of blueschist-facies metamorphism, indicating that it has been subducted to high-pressure/low-temperature conditions during the Alpine Orogeny. Structurally higher units, having been accreted first, record the early metamorphic history of the orogen; lower...

  18. Recurrent Cenozoic volcanic activity in the Bohemian Massif (Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Ulrych, Jaromír; Dostal, J.; Adamovič, Jiří; Jelínek, E.; Špaček, Petr; Hegner, E.; Balogh, K.

    2011-01-01

    Roč. 123, 1/4 (2011), s. 133-144. ISSN 0024-4937 R&D Projects: GA AV ČR(CZ) IAA300130902; GA ČR(CZ) GA205/09/1170 Institutional research plan: CEZ:AV0Z30130516; CEZ:AV0Z30120515 Keywords : Bohemian Massif * Cenozoic * alkaline volcanism * paleostress fields * rift * mantle Subject RIV: DB - Geology ; Mineralogy Impact factor: 3.246, year: 2011

  19. China's National Assessment Report on Climate Change (Ⅰ): Climate change in China and the future trend%气候变化国家评估报告(Ⅰ):中国气候变化的历史和未来趋势

    Institute of Scientific and Technical Information of China (English)

    丁一汇; 任国玉; 石广玉

    2007-01-01

    The climate change in China shows a considerable similarity to the global change, though there still exist some significant differences between them. In the context of the global warming, the annual mean surface air temperature in the country as a whole has significantly increased for the past 50 years and 100 years, with the range of temperature increase slightly greater than that in the globe. The change in precipitation trends for the last 50 and 100 years was not significant, but since 1956 it has assumed a weak increasing trend. The frequency and intensity of main extreme weather and climate events have also undergone a significant change. The researches show that the atmospheric CO2 concentration in China has continuously increased and the sum of positive radiative forcings produced by greenhouse gases is probably responsible for the country-wide climate warming for the past 100 years, especially for the past 50 years. The projections of climate change for the 21st century using global and regional climate models indicate that, in the future 20-100 years, the surface air temperature will continue to increase and the annual precipitation also has an increasing trend for most parts of the country.

  20. The Middle Miocene Climate Transition in the Central Mediterranean. Geologica Ultraiectina (326)

    NARCIS (Netherlands)

    Mourik, A.A.

    2010-01-01

    The Middle Miocene Climate Transition (~15-13.7 Ma) is one of the major steps in Cenozoic climate evolution. The rapid expansion of the East Antarctic Ice Sheet at ~13.9 – 13.7 Ma caused important climate changes on a global scale. The aim of this PhD research has been to study the effects of the Mi

  1. Declining sensitivity of the carbonate compensation depth to sea level during the Cenozoic

    Science.gov (United States)

    Armstrong McKay, David I.; Tyrrell, Toby; Wilson, Paul A.

    2016-04-01

    Over the course of the Cenozoic the global carbonate compensation depth (CCD), the depth in the ocean below which carbonate deposited on the seafloor is not preserved, has shifted from a relatively shallow average position (~3000 to 3500 m in the equatorial Pacific) in the Palaeocene to a relatively deep position (~4600 m in the equatorial Pacific) today. Various hypotheses have been proposed to explain this shift, including increased input of terrestrial weathering products to the ocean, decreased bottom-water corrosivity due to increased ocean ventilation, and the decline of shelf carbonates leading to carbonate burial shifting to the deep ocean (known as 'shelf-basin carbonate burial fractionation'). Here we build on earlier attempts to quantify the impacts of carbonate burial fractionation on the CCD by analysing global hypsometric and carbonate burial data and determining the relationship between sea level, shelf carbonate burial extent, and the CCD. We show that if carbonate burial rates remain constant across the Cenozoic then carbonate burial fractionation can explain between 550 and 800 m of the long-term ~1600 m CCD deepening in the equatorial Pacific, ~430 m of which occurring across the Eocene-Oligocene Transition (EOT) ~34 million years ago when the CCD permanently deepened by ~500 m. This finding indicates that other processes dominated CCD change before and after the EOT and during events such as the Mid-Eocene Climatic Optimum (MECO), but a higher resolution global CCD record is required to better constrain the global magnitude of CCD change during these times. We find that the sensitivity of the CCD to sea level change was at its greatest prior to the EOT and then declined by approximately half due to the loss of extensive carbonate platforms at the end of the Eocene and the intersection of the CCD with large tracts of the abyssal plain.

  2. Long-term stability of global erosion rates and weathering during late-Cenozoic cooling.

    Science.gov (United States)

    Willenbring, Jane K; von Blanckenburg, Friedhelm

    2010-05-13

    Over geologic timescales, CO(2) is emitted from the Earth's interior and is removed from the atmosphere by silicate rock weathering and organic carbon burial. This balance is thought to have stabilized greenhouse conditions within a range that ensured habitable conditions. Changes in this balance have been attributed to changes in topographic relief, where varying rates of continental rock weathering and erosion are superimposed on fluctuations in organic carbon burial. Geological strata provide an indirect yet imperfectly preserved record of this change through changing rates of sedimentation. Widespread observations of a recent (0-5-Myr) fourfold increase in global sedimentation rates require a global mechanism to explain them. Accelerated uplift and global cooling have been given as possible causes, but because of the links between rates of erosion and the correlated rate of weathering, an increase in the drawdown of CO(2) that is predicted to follow may be the cause of global climate change instead. However, globally, rates of uplift cannot increase everywhere in the way that apparent sedimentation rates do. Moreover, proxy records of past atmospheric CO(2) provide no evidence for this large reduction in recent CO(2) concentrations. Here we question whether this increase in global weathering and erosion actually occurred and whether the apparent increase in the sedimentation rate is due to observational biases in the sedimentary record. As evidence, we recast the ocean dissolved (10)Be/(9)Be isotope system as a weathering proxy spanning the past approximately 12 Myr (ref. 14). This proxy indicates stable weathering fluxes during the late-Cenozoic era. The sum of these observations shows neither clear evidence for increased erosion nor clear evidence for a pulse in weathered material to the ocean. We conclude that processes different from an increase in denudation caused Cenozoic global cooling, and that global cooling had no profound effect on spatially and

  3. Climate Sensitivity, Sea Level, and Atmospheric CO2

    CERN Document Server

    Hansen, James; Russell, Gary; Kharecha, Pushker

    2012-01-01

    Cenozoic temperature, sea level and CO2 co-variations provide insights into climate sensitivity to external forcings and sea level sensitivity to climate change. Pleistocene climate oscillations imply a fast-feedback climate sensitivity 3 {\\pm} 1 {\\deg}C for 4 W/m2 CO2 forcing for the average of climate states between the Holocene and Last Glacial Maximum (LGM), the error estimate being large and partly subjective because of continuing uncertainty about LGM global surface climate. Slow feedbacks, especially change of ice sheet size and atmospheric CO2, amplify total Earth system sensitivity. Ice sheet response time is poorly defined, but we suggest that hysteresis and slow response in current ice sheet models are exaggerated. We use a global model, simplified to essential processes, to investigate state-dependence of climate sensitivity, finding a strong increase in sensitivity when global temperature reaches early Cenozoic and higher levels, as increased water vapor eliminates the tropopause. It follows that...

  4. First fossil evidence of Connaraceae R. Br. from Indian Cenozoic and its phytogeographical significance

    Indian Academy of Sciences (India)

    Mahasin Ali Khan; Subir Bera

    2016-07-01

    Fossil leaflet impression described here as a new species Rourea miocaudata sp. nov., showing close resemblance with the modern leaflets of Rourea caudata Planch. (Connaraceae R. Br.), has been recorded from the lower part of the Siwalik sediments (Dafla Formation, middle–upper Miocene) exposed at the road-cutting section of Pinjoli area in West Kameng district, Arunachal Pradesh. The importantmorphological characters of the fossil are its narrow elliptic leaflet, cuneate base, long caudate apex, entire margin, eucamptodromous to brochidodromous secondary veins, presence of intersecondary veins, percurrent and reticulate tertiary veins and orthogonally reticulate quaternary veins. This is the first authentic record of the occurrence of leaflet comparable to R. caudata of Connaraceae from the Cenozoic sediments of India and abroad. At present R. caudata does not grow in India and is restricted only in southeast Asia especially in China and Myanmar. This taxon probably migrated to these southeast Asian regions after lower Siwalik sedimentation (middle–upper Miocene) due to climatic change causedby post-Miocene orogenic movement of the Himalaya. The recovery of this species and other earlierdescribed evergreen taxa from the same formation, suggests the existence of a tropical, warm and humid climatic conditions during the depositional period.

  5. First fossil evidence of Connaraceae R. Br. from Indian Cenozoic and its phytogeographical significance

    Science.gov (United States)

    Khan, Mahasin Ali; Bera, Subir

    2016-07-01

    Fossil leaflet impression described here as a new species Rourea miocaudata sp. nov., showing close resemblance with the modern leaflets of Rourea caudata Planch. (Connaraceae R. Br.), has been recorded from the lower part of the Siwalik sediments (Dafla Formation, middle-upper Miocene) exposed at the road-cutting section of Pinjoli area in West Kameng district, Arunachal Pradesh. The important morphological characters of the fossil are its narrow elliptic leaflet, cuneate base, long caudate apex, entire margin, eucamptodromous to brochidodromous secondary veins, presence of intersecondary veins, percurrent and reticulate tertiary veins and orthogonally reticulate quaternary veins. This is the first authentic record of the occurrence of leaflet comparable to R. caudata of Connaraceae from the Cenozoic sediments of India and abroad. At present R. caudata does not grow in India and is restricted only in southeast Asia especially in China and Myanmar. This taxon probably migrated to these southeast Asian regions after lower Siwalik sedimentation (middle-upper Miocene) due to climatic change caused by post-Miocene orogenic movement of the Himalaya. The recovery of this species and other earlier-described evergreen taxa from the same formation, suggests the existence of a tropical, warm and humid climatic conditions during the depositional period.

  6. Interannual climate variability and spatially heterogeneous improvement of agricultural management impede detection of a decreasing trend in nitrate pollution in an agricultural catchment

    Science.gov (United States)

    Fovet, Ophélie; Dupas, Rémi; Durand, Patrick; Gascuel-Odoux, Chantal; Gruau, Gérard; Hamon, Yannick; Petitjean, Patrice

    2016-04-01

    Despite widespread implementation of the nitrate directive in the European Union since the 1990s, the impact on nitrate concentration in rivers is limited (Bouraoui and Grizzetti, 2011). To assess whether this lack of response is due to the long time lags of nitrate transfer or to inadequate programs of measure, long term river and groundwater monitoring data are necessary. This study analyses 15 years of daily nitrate concentration data at the outlet of an intensively farmed catchment in Western France (Kervidy-Naizin, 5 km²) and quarterly nitrate concentration data in the groundwater of two hillslopes equipped with piezometers (Kerroland and Gueriniec) within the same catchment. In this catchment groundwater contribution to annual stream flow is dominant. The objectives of this study were to i) disentangle the influence of interannual climate variability and improvement of agricultural practices (i.e. reduction in N surplus) in the stream chemistry and ii) discuss the reasons for slow catchment recovery from nitrate pollution by comparing trends in groundwater and stream concentrations. Analysis of stream data showed that flow-weighted mean annual concentration at the outlet of the Kervidy-Naizin catchment has decreased by 1.2 mg NO3- l-1 yr-1 from 1999 to 2015. This decrease was slow but significant (p value piezometer transect (4.0 mg NO3- l-1 yr-1) and no significant evolution in the Gueriniec piezometer transect, from 1999 to 2015. This contrasting evolution of groundwater nitrate concentration between the two transects was consistent with data on soil surface nitrogen surplus, with a balanced fertilisation in the Kerroland transect (N surplus close to 0 kg N ha-1 yr-1) and excessive fertilisation in the Gueriniec transect (N surplus > 100 kg N ha-1 yr-1). We conclude that, despite the lags due to pluri annual nitrate transfer through the unsaturated and satured zones in catchments of Western France, significant decrease in nitrate concentration in

  7. Interannual climate variability and spatially heterogeneous improvement of agricultural management impede detection of a decreasing trend in nitrate pollution in an agricultural catchment

    Science.gov (United States)

    Fovet, Ophélie; Dupas, Rémi; Durand, Patrick; Gascuel-Odoux, Chantal; Gruau, Gérard; Hamon, Yannick; Petitjean, Patrice

    2016-04-01

    Despite widespread implementation of the nitrate directive in the European Union since the 1990s, the impact on nitrate concentration in rivers is limited (Bouraoui and Grizzetti, 2011). To assess whether this lack of response is due to the long time lags of nitrate transfer or to inadequate programs of measure, long term river and groundwater monitoring data are necessary. This study analyses 15 years of daily nitrate concentration data at the outlet of an intensively farmed catchment in Western France (Kervidy-Naizin, 5 km²) and quarterly nitrate concentration data in the groundwater of two hillslopes equipped with piezometers (Kerroland and Gueriniec) within the same catchment. In this catchment groundwater contribution to annual stream flow is dominant. The objectives of this study were to i) disentangle the influence of interannual climate variability and improvement of agricultural practices (i.e. reduction in N surplus) in the stream chemistry and ii) discuss the reasons for slow catchment recovery from nitrate pollution by comparing trends in groundwater and stream concentrations. Analysis of stream data showed that flow-weighted mean annual concentration at the outlet of the Kervidy-Naizin catchment has decreased by 1.2 mg NO3- l-1 yr-1 from 1999 to 2015. This decrease was slow but significant (p value noise to the signal: i) deviation in the linear model of nitrate decrease with time was negatively correlated with annual runoff (r = -0.54, p 100 kg N ha-1 yr-1). We conclude that, despite the lags due to pluri annual nitrate transfer through the unsaturated and satured zones in catchments of Western France, significant decrease in nitrate concentration in groundwater and streams should be visible within less than 10 years after implementation of an efficient program of measures. Spatial heterogeneity in the implementation of programs of measures (i.e. reduction of N surplus) is a likely cause of slow, sometimes undetectable, reduction in nitrate

  8. Warm Climates in Earth History

    Science.gov (United States)

    Huber, Brian T.; MacLeod, Kenneth G.; Wing, Scott L.

    1999-12-01

    The study of greenhouse climates in the earth's past leads to a greater understanding of the factors that influence today's climate. In this fully integrated volume, leading experts in paleoclimatology present cutting edge paleontological, geological, and theoretical research to assess intervals of global warmth. Coverage examines warm climate intervals during the Paleozoic, Mesozoic and Cenozoic from the same perspectives: oceanic and terrestrial, theoretical and observational. This approach illuminates the differences and, more importantly, the commonalities of warm climate intervals. The book also provides a comprehensive overview of the advantages and limitations of different types of climate models that are currently used, and it discusses major factors that have caused global climatic change across geologic time scales. Central problems that remain unresolved are clearly identified. The book will be of great interest to researchers in paleoclimatology, and it will also be useful as a supplementary text in advanced undergraduate or graduate level courses in paleoclimatology and earth science.

  9. 分离趋势产量和气候产量的方法探讨%Exploration of method for discrimination between trend crop yield and climatic fluctuant yield

    Institute of Scientific and Technical Information of China (English)

    房世波

    2011-01-01

    The impact of climate change on crops yields had become one of the hotspots in the research on global climate change.The empirical researches of long time-sequence analysis were effective approaches for analysis of relations between crops yields and meteorological factors.In most of empirical researches,the long time-sequence crops yield is generally decomposed into trend yield(which fits the real crop yield by a trend line depended on mathematic model and which is considered as a result of agricultural technology development and agriculture investment),climatic fluctuant yields(which are considered as contribution of climate fluctuation) and random error.As different trend yields come from different mathematic fitting model,it would get different climatic fluctuant yields,even diametrical result(3-point moving average and 5-point moving average may have negative effect in some years).It is the critical steps that how to simulate the trend yield and separate the trend yield to get an correct or more accurate climatic fluctuant yield in such studies.In this paper,a series rules were put forward to show how to choose a more accurate fitting model to calculate trend yield,which may overcome the disadvantage of random choosing models.Take climate change effect on cotton output for an example,the paper wants to explain how to choose fitting model to get an correct trend yield.Puts forward three rules for method selection:trends yield simulation curve should accord with the process of social technology development reality,the variation characteristics of trends yield should have the same or similar trend in whole research region or country(namely the development of social and technical level no significant difference),different administrative regions which have similar climatic conditions should have strong correlation,and the key climate factors of model obtained which affect the research object(crop) growth should be consistent with the crop

  10. The structural evolution of the Ghadames and Illizi basins during the Paleozoic, Mesozoic and Cenozoic: Petroleum implications

    Energy Technology Data Exchange (ETDEWEB)

    Gauthier, F.J. [Anadarko Petroleum Corp., Houston, TX (United States); Boudjema, A. [Somatrach, Algiers (Algeria); Lounis, R. [Anadarko Algeria Corp., Houston, TX (United States)

    1995-08-01

    The Ghadames and Illizi basins cover the majority of the eastern Sahara of Algeria. Geologicaly, this part of the Central Saharan platform has been influenced by a series of structural arches and {open_quotes}moles{close_quotes} (continental highs) which controlled sedimentation and structure through geologic time. These features, resulting from and having been affected by nine major tectonic phases ranging from pre-Cambrian to Tertiary, completely bound the Ghadames and Illizi Basins. During the Paleozoic both basins formed one continuous depositional entity with the Ghadames basin being the distal portion of the continental sag basin where facies and thickness variations are observed over large distances. It is during the Mesozoic-Cenozoic that the Ghadames basin starts to evolve differently from the Illizi Basin. Eustatic low-stand periods resulted in continental deposition yielding the major petroleum-bearing reservoir horizons (Cambrian, Ordovician, Siluro-Devonian and Carboniferous). High-stand periods corresponds to the major marine transgressions covering the majority of the Saharan platform. These transgressions deposited the principal source rock intervals of the Silurian and Middle to Upper Devonian. The main reservoirs of the Mesozoic and Cenozoic are Triassic sandstone sequences which are covered by a thick evaporite succession forming a super-seal. Structurally, the principal phases affecting this sequence are the extensional events related to the breakup of Pangea and the Alpine compressional events. The Ghadames and Illizi basins, therefore, have been controlled by a polphase tectonic history influenced by Pan African brittle basement fracturing which resulted in complex structures localized along the major basin bounding trends as well as several subsidiary trends within the basin. These trends, as demonstrated with key seismic data, have been found to contain the majority of hydrocarbons trapped.

  11. Meso-Cenozoic tectonic evolution and uranium potential evaluations of basins in Beishan-Gansu corridor region

    International Nuclear Information System (INIS)

    Beishan-Gansu Corridor region is located at the intersection of the plates of Tarim, North China, Kazakhstan, Siberia and Qaidam. During the Meso-Cenozoic, the region experienced movements of Indo-sinian, Yanshanian, Sichuanian, North China, Himalayan and Neotectonic, and over 20 medium-small size superimposed continental basins were formed. On the basis of analyzing the tectonic stress field, sediment-filling and structure-deformation; the general trending of tectonic evolution in the Meso-Cenozoic is summarized as three-time compressional uplifting and two-time extensional down-faulting. The different evolution of basins under the above mentioned setting can be divided into six stages according to characteristics of filled sediment. The sand bodies developed in down-faulted basins are favorable for uranium ore-formation as they are formed under humid paleoclimates, and rich in reducing matter. Therefore, the Lower-Middle Jurassic is selected as the main target horizon for sandstone-hosted uranium deposit, and the Lower Cretaceous as the minor one. Although the tectonic reactivation of the target horizon after its deposition was generally strong, the slopes formed in some basins could be favorable for the infiltration of uranium-and oxygen-bearing groundwater into sand bodies and form uranium deposits. According to the favorable sand bodies and tectonic reactivation, the northern parts of Chaoshui and Bayingobi basins are regarded as potential regions which are worthy of further exploration. (authors)

  12. Cenozoic Methane-Seep Faunas of the Caribbean Region.

    Directory of Open Access Journals (Sweden)

    Steffen Kiel

    Full Text Available We report new examples of Cenozoic cold-seep communities from Colombia, Cuba, the Dominican Republic, Trinidad, and Venezuela, and attempt to improve the stratigraphic dating of Cenozoic Caribbean seep communities using strontium isotope stratigraphy. Two seep faunas are distinguished in Barbados: the late Eocene mudstone-hosted 'Joes River fauna' consists mainly of large lucinid bivalves and tall abyssochrysoid gastropods, and the early Miocene carbonate-hosted 'Bath Cliffs fauna' containing the vesicomyid Pleurophopsis, the mytilid Bathymodiolus and small gastropods. Two new Oligocene seep communities from the Sinú River basin in Colombia consist of lucinid bivalves including Elongatolucina, thyasirid and solemyid bivalves, and Pleurophopsis. A new early Miocene seep community from Cuba includes Pleurophopsis and the large lucinid Meganodontia. Strontium isotope stratigraphy suggests an Eocene age for the Cuban Elmira asphalt mine seep community, making it the oldest in the Caribbean region. A new basal Pliocene seep fauna from the Dominican Republic is characterized by the large lucinid Anodontia (Pegophysema. In Trinidad we distinguish two types of seep faunas: the mudstone-hosted Godineau River fauna consisting mainly of lucinid bivalves, and the limestone-hosted Freeman's Bay fauna consisting chiefly of Pleurophopsis, Bathymodiolus, and small gastropods; they are all dated as late Miocene. Four new seep communities of Oligocene to Miocene age are reported from Venezuela. They consist mainly of large globular lucinid bivalves including Meganodontia, and moderately sized vesicomyid bivalves. After the late Miocene many large and typical 'Cenozoic' lucinid genera disappeared from the Caribbean seeps and are today known only from the central Indo-Pacific Ocean. We speculate that the increasingly oligotrophic conditions in the Caribbean Sea after the closure of the Isthmus of Panama in the Pliocene may have been unfavorable for such large

  13. Early Cenozoic Multiple Thrust in the Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    Zhenhan Wu

    2013-01-01

    Full Text Available Recently completed regional geological mapping at a scale of 1 : 250,000 or larger across all of the Tibetan Plateau coupled with deep seismic surveys reveals for the first time a comprehensive depiction of the major early Cenozoic thrust systems resulting from the northward subduction of the Indian Continental Plate. These systems define a series of overlapping north-dipping thrust sheets that thickened the Tibetan crust and lead to the rise of the plateau. The few south-dipping thrusts present apparently developed within a sheet when the back moved faster than the toe. Many of the thrusts are shown to extend to the middle-lower crustal depths by seismic data. The regional thrust systems are the Main Central, Renbu-Zedong, Gangdese, Central Gangdese, North Gangdese, Bangoin-Nujiang, Qiangtang, Hohxil, and South Kunlun Thrusts. The minimal southward displacements of the South Kunlun, Hohxil, South Qiangtang, and Central Gangdese Thrusts are estimated to be 30 km, 25 km, 150 km and 50 km, respectively. Deep thrusting began in the Himalaya-Tibetan region soon after India-Eurasia continental collision and led to crustal thickening and subsequent uplift of the Tibetan Plateau during Late Eocene-Early Miocene when the systems were mainly active. The major thrust systems ceased moving in Early Miocene and many were soon covered by lacustrine strata. This activity succeeded in the late Cenozoic to crustal extension and strike-slip movement in the central Tibetan Plateau. The revelation of the full array of the early Cenozoic thrust systems provides a much more complete understanding of the tectonic framework of the Tibetan Plateau.

  14. Detection of long-term trends in monthly hydro-climatic records of Colombia and the Amazon River basin through Empirical Mode Decomposition

    Science.gov (United States)

    Carmona, A. M.; Poveda, G.

    2011-12-01

    We search for long-term trends in 25- to 50-year records of monthly rainfall (100 stations), average river discharges (42 stations), and mean and minimum air temperature records (37 stations) in Colombia, as well as monthly records in 29 rain gauges within the Amazon River basin. Time series of average monthly river discharges are selected from 10 Colombian river basins with gauging stations located downstream along the main channel. The Empirical Mode Decomposition (EMD) method is used as a filtering process to decompose a given time series into a finite number of intrinsic mode functions (IMF), assuming that diverse simple oscillatory modes of different frequencies coexist in the series, and that the residual captures the long-term trend of the record. The Mann-Kendall test for autocorrelated data is used to assess the statistical significance of the trends, and the Sen test is used for the magnitude of the trends. Results show that 62% of monthly river discharge series exhibit decreasing trends between 0.01-1.92 m3/s yr-1. The identified trends are strongly consistent downstream, albeit with contrasting results for the ratios between the magnitude of the trend and mean discharges. Most minimum temperature series (87%) show increasing trends [0.01-0.08°C yr-1]. Results on precipitation are inconclusive as monthly records exhibit a mixed pattern of increasing (41%, between 0.1-7.0 mm yr-1) and decreasing (44%, between 0.1-7.4 mm yr-1) trends, except for the Pacific region, which shows clear-cut positive trends, consistently with an increasing trend identified in the strength of the Chocó low-level jet winds over the Pacific coast of Colombia, the main moisture advection mechanism into the region. Maximum trend magnitudes in precipitation records on the Amazon basin were found to be decreasing (53%, between 0.04 -9.1 mm yr-1), mostly around the basin's central and south-eastern regions. The highest decreasing trend magnitude in the Amazon was found to be -9.1mm

  15. Uranium and thorium in Cenozoic basaltods of Kamchatka

    International Nuclear Information System (INIS)

    Regularities in distribution of radioactive elements (RAE) in basaltoids of Kamchatka have been analyzed. The RAE concentration in samples was determined by γ-spectrometric method. The results compared with the instrumental neutron-activation analysis data are found to be in agreement. Results of evaluating the average contents of U, Th and roch-forming elements in ce-- nozoic basaltoids are presented. The radiogeochemical data enable to associate the origin of the Kamchatka Cenozoic basaltoids with both fractional melting of the upper mantle depleted of radioactive elements and the development of magmatic chambers in submerged blocks of the Pre-Cretaceous melanocratic basement the composition of which is close to oceanic tholeiite

  16. Radiometric age of Cenozoic volcanism and paleomagnetic research

    Czech Academy of Sciences Publication Activity Database

    Cajz, Vladimír; Schnabl, Petr; Radoň, M.

    [Praha]: Česká geologická společnost, 2011 - (Verner, K.; Buriánek, D.; Budil, P.). s. 24-24 ISBN 978-80-87487-00-6. [Otevřený kongres České geologické společnosti a Slovenskej geologickej spoločnosti /2./. 21.09.2011-25.09.2011, Monínec] Institutional research plan: CEZ:AV0Z30130516 Keywords : volcanism * paleomagnetism * Cenozoic Subject RIV: DB - Geology ; Mineralogy http://www.geologickykongres.eu/OGK11/abstrakty/OGK11_24.pdf

  17. Thermal state of the Roer Valley Graben, part of the European Cenozoic Rift System

    NARCIS (Netherlands)

    Luijendijk, E.; Voorde, M. ter; Balen, R. van; Verweij, H.; Simmelink, E.

    2011-01-01

    We performed a detailed analysis of the thermal state of the Cenozoic Roer Valley Graben, the north-western branch of the European Cenozoic Rift System, based on a new set of temperature data. We developed a numerical technique for correcting bottom hole temperatures, including an evaluation of the

  18. First paleomagnetic results from Cenozoic volcanics of Lusatian region, Saxony/Bohemia

    Czech Academy of Sciences Publication Activity Database

    Cajz, Vladimír; Schnabl, Petr; Büchner, J.; Tietz, O.; Suhr, P.; Pécskay, Z.; Čížková, Kristýna; Šlechta, Stanislav

    Prague: Czech Geological Survey ; Senckenberg museum of natural History Görlitz, 2013 - (Büchner, J.; Rapprich, V.; Tietz, O.). s. 189-190 ISBN 978-80-7075-806-9. [Basalt 2013: Cenozoic magmatism in Central Europe. 24.04.2013-28.04.2013, Görlitz] Institutional support: RVO:67985831 Keywords : Cenozoic * paleomagnetism * Lusation region Subject RIV: DB - Geology ; Mineralogy

  19. A major reorganization of Asian climate by the early Miocene

    OpenAIRE

    Z. T. Guo; Sun, B; Z. S. Zhang; Peng, S. Z.; G. Q. Xiao; Ge, J. Y.; Q. Z. Hao; Qiao, Y. S.; M. Y. Liang; Liu, J F; Q. Z. Yin; Wei, J. J.

    2008-01-01

    The global climate system experienced a series of drastic changes during the Cenozoic. In Asia, these include the climate transformation from a zonal pattern to a monsoon-dominated pattern, the disappearance of typical subtropical aridity, and the onset of inland deserts. Despite major advances in the last two decades in characterizing and understanding these climate phenomena, disagreements persist relative to the timing, behaviors and underlying causes....

  20. Cenozoic Tectonic Activity of the "Passive" North America Margin: Evidence for Cenozoic Activity on Mesozoic or Paleozoic Faults

    Science.gov (United States)

    Nedorub, O. I.; Knapp, C. C.

    2012-12-01

    The tectonic history of the Eastern North American Margin (ENAM) incorporates two cycles of continental assembly, multiple pulses of orogeny, rifting, and post-rift geodynamic evolution. This is reflected in the heterogeneous lithosphere of the ENAM which contains fault structures originated in Paleozoic to Mesozoic eras. The South Georgia Rift basin is probably the largest Mesozoic graben within its boundaries that is associated with the breakup of Pangea. It is composed of smaller sub-basins which appear to be bounded by high-angle normal faults, some of which may have been inverted in late Cretaceous and Cenozoic eras. Paleozoic structures may have been reactivated in Cenozoic time as well. The ENAM is characterized by N-NE maximum horizontal compressive stress direction. This maximum compressional stress field is sub-parallel to the strike of the Atlantic Coast province fault systems. Camden, Augusta, Allendale, and Pen Branch faults are four of the many such reactivated faults along the southern part of ENAM. These faults are now buried under the 0-400 m of loosely consolidated Cretaceous and Cenozoic age sediments and thus are either only partially mapped or currently not recognized. Some of the objectives of this study are to map the subsurface expression and geometry of these faults and to investigate the post Cretaceous deformation and possible causes of fault reactivation on a passive margin. This study employs an integrated geophysical approach to investigate the upper 200 m of identified locations of the above mentioned faults. 2-D high-resolution shallow seismic reflection and refraction methods, gravity surveys, GPR, 2-D electrical resistivity and well data are used for analyses and interpretation. Preliminary results suggest that Camden fault shows signs of Cenozoic reactivation through an approximately 30 m offset NW side up mainly along a steeply dipping fault zone in the basal contact of Coastal Plain sediments with the Carolina Piedmont. Drill

  1. Cenozoic tectono-geomorphological growth of the SW Chinese Tian Shan: Insight from AFT and detrital zircon U-Pb data

    Science.gov (United States)

    Jia, Yingying; Fu, Bihong; Jolivet, Marc; Zheng, Shuo

    2015-11-01

    As a unique example of the intracontinental mountain building, the Cenozoic deformation of the Tian Shan has been widely studied. The onset of Cenozoic exhumation of the SW Chinese Tian Shan was constrained at the Oligocene-Miocene boundary. However, the Cenozoic tectono-geomorphological growth process of the SW Chinese Tian Shan and adjacent piedmont basins remains a challenge. In this study, we carried out the geological mapping of satellite images and field investigations together with the apatite fission track (AFT) and detrital zircon U-Pb analyses to get further understanding of the Cenozoic tectonic deformation and geomorphological growth of the SW Chinese Tian Shan. Our results indicate that the exhumation of the hanging wall of Maidan fault or topography growth of the Kokshaal Range commenced in the late Eocene-Oligocene (35-25 Ma). Then, the structural deformation migrated southward to the Muziduke fault and the Atushi Basin Thrust (ABT) at ∼15 Ma. The growth strata of 6-3 Ma on the south flank of Keketamu Anticline imply that tectonic deformation propagates further basinward. Furthermore, the uplift of the Kokshaal Range also strongly affected the evolution of piedmont basins. The results suggest that the Atushi Basin was still likely linked to the Aksai Basin during the early Miocene. They were separated into two independent basins since ca. 13.7-10.5 Ma, as a response to the rapid uplift of the Kokshaal Range. Finally, we infer that the southeastern part of dextral Talas-Fergana fault (TFF) is likely transferred to the NEE-trending thrust faults of the SW Chinese Tian Shan since ∼15 Ma.

  2. North Chilean forearc tectonics and cenozoic plate kinematics

    Science.gov (United States)

    Buddin, Tim S.; Stimpson, Ian G.; Williams, Graham D.

    1993-04-01

    The continental forearc of northern Chile has been subjected to contemporaneous extension and compression. Here, cross-sections constructed across the forearc are presented which show that since initial shortening, deformation of the forearc has occurred in two tectonically distinct areas. These inner and outer forearc areas are separated by the strain discontinuity of the Atacama fault system and the tectonically neutral Central Depression. The outer forearc, the Coastal Cordillera, exhibits extensional tectonics, with large (up to 300 m) normal fault scarps preserved. These faults cut the earlier thrusts responsible for the elevation of Jurassic rocks at the coast above their regional elevation. The normal faults have been re-activated, displacing Quaternary salt deposits in the Salar Grande. This re-activation of the basement faults is probably due to the subduction of anomalously thick oceanic crust, producing an isostatic imbalance in the outer forearc. In the inner forearc, cross-sections through the Sierra del Medio and Cordillera de Domeyko show that structures of the Pre-Cordillera are best explained by a thick-skinned thrust system, with localized thin-skinned tectonics controlled by evaporite detachment horizons. Current forearc deformation features indicate a strong degree of correlation between subduction zone geometry and forearc tectonics. The timing of Cenozoic tectonism also fits well with established plate motion parameters, and the spatial and temporal variation in the state of stress of the forearc shows a close relationship throughout the Cenozoic to the plate kinematics and morphology of the subducting Nazca plate.

  3. Mesozoic and Cenozoic formations uraniferous activity. Chapter 3

    International Nuclear Information System (INIS)

    The main features of geological structure and history of forming Mesozoic and Cenozoic structure and formations complexes are given. Forming of Mesozoic-Cenozoic Depressive structures had been going on under the condition of infiltrations regime of artesian basins with forming of regional ground and stratum oxidation zones in Zhalpak and Paleogenic sediments which are including uranium deposits belonging to four uranium ore formation. The main raw materials base and extraction of uranium by in-situ leaching method are connected with deposits of epigenetic uranium-ore formation of regional stratum oxidation zones. There are most important deposits: Maikuduk, Inkai, Zhalpak, Uvanas, Suluchekenskoe, Koldzatskoe, Nizhneilyiskoe. All deposits are described according to same plan: stratigraphy, tectonic structure, hydrogeology, hydrochemics, uranium mineralization, morphology of deposits, mineral compound of ores, geologic characteristics of ores, genetics. Except uranium, the main deposit component, there is an information about the accompanied elements: rhenium, selenium, rare-earth ones, industrial concentration of which are in competitions with the same elements extracted from ores

  4. Confronting Climate Model Simulations with Satellite-Based Evaluation of Warm Rain Formation: Can We Reconcile "Bottom-up" Process-Based Constraints with the "Top-Down" Temperature Trend Constraints?

    Science.gov (United States)

    Golaz, J. C.; Suzuki, K.; Guo, H.

    2014-12-01

    Cloud parameterizations in climate models include a number of adjustable parameters that arise from uncertainties in cloud processes. These parameters are often tuned to best reproduce specific aspects of the observed climate, such as the energy balance at the top of the atmosphere. Starting with the CMIP5 GFDL CM3 coupled climate model, we construct alternate model configurations that achieve the desired energy balance using different, but plausible, combinations of parameters. The present-day climate is nearly indistinguishable in all configurations, but the evolution of the surface temperature from pre-industrial to present-day differs markedly among these configurations due to a large spread in the magnitude of the aerosol indirect effect. Details of the cloud-to-rain conversion processes are found to be the source for this large spread. Recently developed methodologies to analyze the CloudSat and A-Train satellite observations are employed to construct the statistical "fingerprint" process-level signatures of the cloud-to-rain processes. These methodologies are applied to both satellite observations and climate models. Such comparisons can be used to help constrain uncertain parameters included in cloud parameterizations. One of the highlighted results demonstrates that the model predictability of twentieth-century historical temperature trends contradicts the process-based constraint on a tunable cloud parameter. This implies the presence of compensating errors at a fundamental level, and underscores the importance of observation-based, process-level constraints on model microphysics uncertainties for more reliable predictions of the aerosol indirect effect. This uncertainty in the magnitude of the aerosol indirect effect ultimately limits our ability to constrain the climate sensitivity.

  5. 未来气候情景下西藏地区的干湿状况变化趋势%Trends Of Tibet's Dry-Wet Condition under Future Climate Scenario

    Institute of Scientific and Technical Information of China (English)

    赵俊芳; 郭建平; 房世波; 毛飞

    2011-01-01

    The drought is one of the important meteorological disasters in Tibet, and occurs in varying degrees each year. The drought has a great impact on the agriculture and livestock production. It has an important significance that forecasting the trends of Tibet's dry-wet condition under future climate scenario for prevention and reduction of losses caused by drought in the region. Based on the daily data of A2 climate scenario (2011 -2050) and baseline climate condition (1961 -1990) from the regional climate model PRECIS with resolution of 50km × 50km, reference crop evapotranspiration was calculated according to Penman-Monteith equation recommended by FAO. In terms of grades of wetness index from Chinese Climate Classification Criterion, Tibet is classified into arid, semi-arid, semi-humid and humid zones, respectively. The possible temporal-spatial changes of dry-wet condition in Tibet from 2011 to 2050 were analyzed based on wetness index. The results showed that: the amount of precipitation and reference crop evapotranspiration in the most regions of Tibet would increase from 2011 to 2050 compared with the baseline climate conditions from 1961 to 1990. The increase range of reference crop evapotranspiration was less than that of precipitation. However, the inter-regional differences were both significant; in the next 40 years, Tibet's climate showed a warming and wetting trend in general. The reducing trends in arid and semi-arid areas were clear. And the increase range of average temperature was far greater than that of wetness index. Environmental water and heat factors were higher and drought gradually decreased. It was more conducive to the improvement of ecological environment; however, the different climatic zones in dry-wet conditions at different times showed different trends. The area's reducing trend in the arid and semiarid region and the expanding trend in the humid and semi-humid region during 2021 to 2030 would be obvious compared with the

  6. On the meso-cenozoic mantle plume tectonics, its relationship to uranium metallogenesis and prospecting directions in South China

    International Nuclear Information System (INIS)

    The author briefly introduces the research history and trends on mantle plume tectonics, which is considered to be primary origins of geotectonics-volcanism/magmatism-sedimentation-metamorphism and metallogenesis system. The activities of the Meso-Cenozoic mantle plume tectonics, its features and relationship to uranium mineralization in South China are discussed. The classified four main types of uranium deposits in South China must be formed under direct or indirect influence of the mantle plume tectonics, which provides not only dynamic energy for processes of uranium migration, mobilization and enrichment, but also ore sources for mineralization. Those considerations are of important significance to more deeply understanding uranium regional metallogenetic regularity, enlarging resources of the known ore fields and searching for new uranium mineralized areas and mineralization types as well

  7. Temporal evolution of island arc magmatism: geochronology, petrology et geochemistry of mesozoic and cenozoic magmatic rocks from Sumatra (Indonesia)

    International Nuclear Information System (INIS)

    Sumatra island (Western Indonesia) belongs to the Sunda magmatic arc, which results from the subduction of the Indian ocean plate beneath the margin of the Eurasiatic continental block. Plutonic and volcanic rocks of Mesozoic and Cenozoic ages are very abundant in Sumatra, where they mainly outcrop in a NNW-SSE trending, 1,650 km-long stripe in the western part of the island. The spatial and temporal distributions of magmatic rocks in Sumatra were not previously investigated in detail. We have performed 175 40K-40Ar datings on bulk rocks and minerals separated from samples which have also been analysed for major and trace elements by ICP-AES. These results allow to discuss the distribution of magmatic events in space of a long subduction period on the chemical composition of the Sunda arc mantle wedge. (author)

  8. Time series analysis of Cenozoic era sea level and paleotemperature data

    Science.gov (United States)

    Rosenfield, George H.; Huffman, Tod E.

    1983-01-01

    A statistical analysis of Cenozoic era sea level and paleotemperature data was performed to determine the cycles of each data set and the correspondence between them. Accordingly, each of the four time series were first analyzed independently in the univariate mode of a spectral analysis. The two basic data sets were then analyzed in a paired cross-spectral analysis. The prominent periodic cycles remaining in the data sets after linear trend removal, were: sea level surface from seismic stratigraphy--9.6 million years, updated version of sea level surface from seismic stratigraphy--9.5 million years, continental paleotemperatures from paleobotanical interpretations--9.6 million years, and marine paleotemperatures from foraminiferal isotopic data--12.7 million years. The cross-correlation properties between the data sets of continental paleotemperatures from paleobotanical interpretations and sea level surface from seismic stratigraphy at the common prominent period of 9.6 million years were: (1) The squared coherency value which measures cross correlation between the two data sets has the value 0.30, and (2) the amount by which the continental paleotemperatures from paleobotanical interpretations data lags the sea level surface from seismic stratigraphy data is 2.70 million years.

  9. Late Cenozoic Tectonic Deformation in the Dongsha Islands and Adjacent Sea Area

    Institute of Scientific and Technical Information of China (English)

    WU Shiguo(吴时国); LIU Zhan(刘展); WANG Wanyin(王万银); GUO Junhua(郭军华); T. Lüdmann; H. K. Wong

    2003-01-01

    Dongsha Island and the adjacent sea area locate at the northern continental margin of the South China Sea (SCS), and is connected to the east by the Manila Trench. Analyses of seismic stratigraphy and gravity, magnetic and drilling wells data led to the discovery of three post-fault sequences (V, VI, VII). Extensive tectonic uplift, magma activity and erosion occurred in Dongsha Island and the adjacent area, where most of the faults in the northeastern SCS were still active during Pliocene and Quaternary. Two groups of faults trending NEE and NW were developed during Late Cenozoic. We conclude that three important tectonic movements, especially Dongsha movement (4.4-5.2 Ma) and Liuhua movement (1.4-1.89 Ma), controlled the structural framework in the Dongsha rise; whose deformation in the east is stronger than that in the west and whose stress field variation suggests that the tectonic uplift in the study area contributed to magmato-tectonic events correlated to the main collision phases between the East China and Taiwan 5-3 and 3-0 Ma ago.

  10. Active faults paragenesis and the state of crustal stresses in the Late Cenozoic in Central Mongolia

    Directory of Open Access Journals (Sweden)

    V. A. Sankov

    2015-12-01

    Full Text Available Active faults of the Hangay-Hentiy tectonic saddle region in Central Mongolia are studied by space images interpretation, relief analysis, structural methods and tectonic stress reconstruction. The study results show that faults activation during the Late Cenozoic stage was selective, and a cluster pattern of active faults is typical for the study region. Morphological and genetic types and the kinematics of faults in the Hangay-Hentiy saddle region are related the direction of the ancient inherited structural heterogeneities. Latitudinal and WNW trending faults are left lateral strike-slips with reverse or thrust component (Dzhargalantgol and North Burd faults. NW trending faults are reverse faults or thrusts with left lateral horizontal component. NNW trending faults have right lateral horizontal component. The horizontal component of the displacements, as a rule, exceeds the vertical one. Brittle deformations in fault zones do not conform with the Pliocene and, for the most part, Pleistocene topography. With some caution it may be concluded that the last phase of revitalization of strike slip and reverse movements along the faults commenced in the Late Pleistocene. NE trending disjunctives are normal faults distributed mainly within the Hangay uplift. Their features are more early activation within the Late Cenozoic and the lack of relation to large linear structures of the previous tectonic stages. According to the stress tensor reconstructions of the last phase of deformation in zones of active faults of the Hangay-Hentiy saddle using data on tectonic fractures and fault displacements, it is revealed that conditions of compression and strike-slip with NNE direction of the axis of maximum compression were dominant. Stress tensors of extensional type with NNW direction of minimum compression are reconstructed for the Orkhon graben. It is concluded that the activation of faults in Central Mongolia in the Pleistocene-Holocene, as well as

  11. Tectono-climatic implications of Eocene Paratethys regression in the Tajik basin of central Asia

    Science.gov (United States)

    Carrapa, Barbara; DeCelles, Peter G.; Wang, Xin; Clementz, Mark T.; Mancin, Nicoletta; Stoica, Marius; Kraatz, Brian; Meng, Jin; Abdulov, Sherzod; Chen, Fahu

    2015-08-01

    Plate tectonics and eustatic sea-level changes have fundamental effects on paleoenvironmental conditions and bio-ecological changes. The Paratethys Sea was a large marine seaway that connected the Mediterranean Neotethys Ocean with Central Asia during early Cenozoic time. Withdrawal of the Paratethys from central Asia impacted the distribution and composition of terrestrial faunas in the region and has been largely associated with changes in global sea level and climate such as cooling associated with the Eocene/Oligocene transition (EOT). Whereas the regression has been dated in the Tarim basin (China), the pattern and timing of regression in the Tajik basin, 400 km to the west, remain unresolved, precluding a test of current paleogeographic models. Here we date the Paratethys regression in Tajikistan at ca. 39 million years ago (Ma), which is several million years older than the EOT (at ca. 34 Ma) marking the greenhouse to icehouse climate transition of the Cenozoic. Our data also show a restricted, evaporitic marine environment since the middle-late Eocene and establishment of desert like environments after ca. 39 Ma. The overall stratigraphic record from the Tajik basin and southern Tien Shan points to deposition in a foreland basin setting by ca. 40 Ma in response to active tectonic growth of the Pamir-Tibet Mountains at the same time. Combined with the northwestward younging trend of the regression in the region, the Tajik basin record is consistent with northward growth of the Pamir and suggests significant tectonic control on Paratethys regression and paleoenvironmental changes in Central Asia.

  12. Mesozoic extension and Cenozoic contraction in an intraplate setting (Maestrat basin, Iberian Chain, E Spain)

    Science.gov (United States)

    Nebot Miralles, M.; Guimerà Roso, J.

    2013-12-01

    The Iberian Chain, located in the eastern Iberian Peninsula, is a fold-and-thrust belt developed during the Cenozoic, because of the contractional inversion of the Mesozoic Iberian Rift System. The extension in the Iberian Chain took place in two major rifting cycles (late Permian to late Triassic and late Oxfordian to late Albian) followed by episodes of lower rifting activity (early and middle Jurassic, and late Albian to Maastrichtian). The Maestrat basin (containing up to 6.5 km of Mesozoic sediments) is one of the most subsident basins during the late Oxfordian to late Albian cycle. A system of listric extensional faults, which involve the basement, bounded the basin, and also divided it into minor sub-basins, containing different thicknesses of the Mesozoic sedimentary fill. An E-W-trending, N-verging, fold-and-thrust belt developed in the northern boundary of the basin, as the result of the Cenozoic inversion. This belt involved the Mesozoic cover in the northern -foreland- areas, with a detachment level located within the Triassic: in the Middle Muschelkalk (Middle Triassic) and Keuper (Upper Triassic), both formed by lutites and evaporites. Southwards, the thrust-system also involved the Variscan basement. A study of the region containing the transition between the thin-skinned and the thick-skinned areas is presented, based on seismic profiles, oil-exploration wells and field data. A progressive northward thickening of Jurassic and lower Cretaceous units, related to a S-dipping listric extensional fault located to the N, can be observed both in the field and the seismic profiles. In the Triassic rocks, depositional thickness variations in the Middle Muschelkalk unit are observed, related to sub-vertical faults active during the Triassic rifting. Salt anticlines, pillows and welds are also observed in the Middle Muschelkalk. These halocynetic structures developed during the Keuper, as it is deduced from the onlap geometries of the Keuper seismic reflectors

  13. Variations in sediment transport at the central Argentine continental margin during the Cenozoic

    Science.gov (United States)

    Gruetzner, Jens; Uenzelmann-Neben, Gabriele; Franke, Dieter

    2012-10-01

    The construction of the sedimentary cover at most passive continental margins includes gravitational downslope transport and along-slope contourite deposition, which are controlled by tectonics, climate and oceanography. At the eastern continental margin of Argentina the history of deposition and erosion is intimately linked to the evolution of the South Atlantic and its water masses. Here we present a detailed seismic investigation of the mixed depositional system located between 41°S and 45°S. The study provides a northward complement to prior investigations from the southern Argentine margin and together with these may be used as background information for future ocean drilling in the region. Prominent features in our seismic cross sections are submarine canyons, mass wasting deposits, contourite channels, and sediment drifts. Four major seismic units above regional reflector PLe (˜65 Ma) are separated by distinct unconformities of regional extent. Using a dense grid of reflection seismic profiles, we mapped the depocenter geometries of the seismic units and derived a chronology of the depositional processes during the Cenozoic. While the Paleocene/Eocene (˜65-34 Ma) is characterized by hemipelagic sedimentation under relatively sluggish bottom water conditions, strong Antarctic bottom water (AABW) circulation led to widespread erosion on the slope and growth of a detached sediment drift during the Oligocene and early Miocene (˜34-17 Ma). After deposition of an aggradational seismic unit interpreted to represent the Mid-Miocene climatic optimum (˜17-14 Ma), gravitational downslope sediment transport increased during the middle to late Miocene (˜14-6 Ma) possibly related to tectonic uplift in South America. The Pliocene to Holocene unit (<˜6 Ma) is very heterogeneous and formed by interactions of downslope and along-slope sediment transport processes as indicated by the evolution of canyons, slope plastered drifts and channels.

  14. Types of Cenozoic Mollusca from Java in the Martin Collection of Naturalis

    NARCIS (Netherlands)

    Leloux, J.; Wesselingh, F.P.

    2009-01-01

    An updated type catalogue of the Martin Collection (fossil Mollusca, predominantly from the Cenozoic of Java, Indonesia) is presented. Type specimen data, updated locality data, and illustrations are given.

  15. Preserving species populations in the boreal zone in a changing climate: contrasting trends of bird species groups in a protected area network

    OpenAIRE

    Raimo Virkkala; Ari Rajasärkkä

    2012-01-01

    A protected area network should ensure the maintenance of biodiversity. Because of climate change, species ranges are expected to move polewards, causing further demand for the protected area network to be efficient in preserving biota. We compared population changes of different bird species groups according to their habitat preferences in boreal protected areas in Finland on the basis of large-scale censuses carried out in 1981–1999 and in 2000–2009. Population densities of comm...

  16. Climatic change

    International Nuclear Information System (INIS)

    In spite of man's remarkable advances in technology, ultimately he is still dependent on the Earth's climatic system for food and fresh water. The recent occurrences in certain regions of the world of climatic extremes such as excessive rain or droughts and unseasonably high or low temperatures have led to speculation that a major climatic change is occurring on a global scale. Some point to the recent drop in temperatures in the northern hemisphere as an indication that the Earth is entering a new ice age. Others see a global warming trend that may be due to a build-up of carbon dioxide in the atmosphere. An authoritative report on the subject has been prepared by a World Meteorological Organization Panel of Experts on Climatic Change. Excerpts from the report are given. (author)

  17. Cenozoic tectonics of the Tuz Gölü Basin (Central Anatolian Plateau, Turkey)

    OpenAIRE

    FERNÁNDEZ-BLANCO, David; BERTOTTI, Giovanni; ÇİNER, T. Attila

    2013-01-01

    We present a new 3D geologic model for the architecture and Cenozoic tectonic evolution of the Tuz Gölü Basin, a major sedimentary basin in the Central Anatolian orogenic plateau. This model is grounded on 7 depth-converted seismic reflection profiles in combination with the analysis of backstripped subsidence curves, isochore maps, and a palinspastically restored cross-section. Two stages of basin formation are detected during Cenozoic times. During the Palaeogene, around 2 km of basement su...

  18. Interaction between Cenozoic fault activity and sediment influx in the Arctic region: new thermochronologic data and seismic study

    Science.gov (United States)

    Bigot-Buschendorf, Maelianna; Mouthereau, Frédéric; Fillon, Charlotte; Loget, Nicolas; Labrousse, Loïc; Werner, Philippe; Bernet, Matthias; Ehlers, Todd

    2015-04-01

    The Alaskan Brooks Range and its canadian counterpart, the British Mountains result from the Meso-Cenozoic collision of the Arctic continental margin with accreted volcanic arcs and adjacent continental terranes. Because of its location and known potential for oil industries, more attention has been brought to this area for the last few years. While the timing of collisional events, duration, and rates of exhumation associated with mountain building is now better understood, the causes of these exhumation events are still largely unknown. Published constraints and our present data are consistent with progressive cooling from 105 to 25 Ma, with rates of exhumation constant across the range until 35-25 Ma. From 35 Ma onwards, exhumation likely slowed in concomitance with underplating/duplexing in the inner part of the belt (Doonerak window) and activation of the northernmost thrust. The earliest cooling stage (from 100 Ma) marking the onset of the Brookian orogeny is recorded by a low order coarsening upward sequence in the foreland. On the contrary, the latest stage of cooling (at 35 Ma) is not linked to the construction of the range but more likely due to a reorganization of the wedge possibly related to changes in the regional climatic or geodynamic boundary conditions. First, we aim at reconstructing the time-temperature evolution of the British Mountains by combining new (U-Th)/He and fission-tracks ages on zircon and apatite ; our first thermochronological data in the British Mountains show ages ranging from 110 to 25 Ma from range to basin. These data will permit to reconstruct the thermal history of the British Mountains and its basin, and to estimate the exhumation rates associated to the main unities. Then, we also examine the role of climate during the Tertiary period. Some markers indicate a climate change at this period which could be registered in the sedimentation. Therefore we determine the part of climate by analyzing seismic lines in the Beaufort

  19. Cenozoic crustal shortening and thickening contributions to Andean orogenesis: Preliminary results from structural mapping in the southern Peruvian Andes

    Science.gov (United States)

    Perez, N.; Horton, B. K.

    2012-12-01

    Estimates of Cenozoic crustal shortening and thickening from the southern Peruvian Andes are necessary to address ongoing debates regarding growth of the Andes and Altiplano plateau. However, limited regional studies in southern Peru prevent accurate assessments of the structural contributions to high topography. This study provides new structural mapping along a >200 km transect spanning the northernmost Altiplano to Subandes at 13-15.5°S and fills the gap between existing central Peruvian and northern Bolivian studies. New stratigraphic data, fault relationships and fold orientations are used to create an updated geologic map and provide insights into the style, timing and magnitude of crustal deformation. Preliminary cross sections accompanying these map transects illustrate deformation style and provide first-order estimates of shortening. Further cross section analyses will be balanced and provide estimates of total crustal shortening and associated thickening in southern Peru. The study transect is subdivided into belts according to the age of exposed rocks and style of deformation. From west to east these belts include: Cretaceous strata dominated by tight folds, closely spaced faults and multiple detachments; Permo-Triassic strata dominated by thicker thrust sheets and fault-fold orientations departing from typical Andean trends; and Paleozoic rocks characterized by thick thrust sheets and deformation focused near major faults. The Cretaceous belt is composed of marine limestones and upward coarsening, siltstone to coarse sandstone progradational sequences. Disharmonic and detachment folds in the Cretaceous section demonstrate the importance of interbedded gypsum and mudstone layers. Fault relationships suggest local shortening during the Early Cretaceous. The Permo-Triassic belt is composed of thick Permian carbonates (Copacabana Formation) and interbedded sandstones, conglomerates and volcanics of the Mitu Formation. This study defines the orientation of

  20. Trend analysis

    International Nuclear Information System (INIS)

    The goal of exploration is to find reserves that will earn an adequate rate of return on the capital invested. Neither exploration nor economics is an exact science. The authors must therefore explore in those trends (plays) that have the highest probability of achieving this goal. Trend analysis is a technique for organizing the available data to make these strategic exploration decisions objectively and is in conformance with their goals and risk attitudes. Trend analysis differs from resource estimation in its purpose. It seeks to determine the probability of economic success for an exploration program, not the ultimate results of the total industry effort. Thus the recent past is assumed to be the best estimate of the exploration probabilities for the near future. This information is combined with economic forecasts. The computer software tools necessary for trend analysis are (1) Information data base - requirements and sources. (2) Data conditioning program - assignment to trends, correction of errors, and conversion into usable form. (3) Statistical processing program - calculation of probability of success and discovery size probability distribution. (4) Analytical processing - Monte Carlo simulation to develop the probability distribution of the economic return/investment ratio for a trend. Limited capital (short-run) effects are analyzed using the Gambler's Ruin concept in the Monte Carlo simulation and by a short-cut method. Multiple trend analysis is concerned with comparing and ranking trends, allocating funds among acceptable trends, and characterizing program risk by using risk profiles. In summary, trend analysis is a reality check for long-range exploration planning

  1. Impact of Cenozoic strike-slip tectonics on the evolution of the northern Levant Basin (offshore Lebanon)

    Science.gov (United States)

    Ghalayini, Ramadan; Daniel, Jean-Marc; Homberg, Catherine; Nader, Fadi H.; Comstock, John E.

    2014-11-01

    Sedimentary basins adjacent to plate boundaries contain key tectonic and stratigraphic elements to understand how stress is transmitted through plates. The Levant Basin is a place of choice to study such elements because it flanks the Levant Fracture System and the Africa/Anatolia boundary. This paper uses new high-quality 3-D seismic reflection data to unravel the tectonic evolution of the margin of this basin during the Cenozoic, the period corresponding to the formation of the Levant Fracture System, part of the Africa/Arabia plate boundary. Four major groups of structures are identified in the interpreted Cenozoic units: NW-SE striking normal faults, NNE-SSW striking thrust-faults, ENE-WSW striking dextral strike-slip faults, and NNE trending anticlines. We demonstrate that all structures, apart of the NW-SE striking normal faults, are inherited from Mesozoic faults. Their reactivation and associated folding started during the late Miocene prior to the Messinian salinity crisis due to a NW-SE compressional stress field. No clear evidence of shortening at present-day offshore Lebanon and no large NNE-SSW strike-slip faults parallel to the restraining bend are found indicating that the Levant Fracture System is mainly contained onshore at present day. The intermittent activity of the interpreted structures correlates with the two stages of Levant Fracture System movement during late Miocene and Pliocene. This paper provides a good example of the impact of the evolution of plate boundaries on adjacent basins and indicates that any changes in the stress field, as controlled by the plate boundary, will affect immediately the preexisting structures in adjacent basins.

  2. Mesozoic and Cenozoic uplift and exhumation of the Bogda Mountain, NW China:Evidence from apatite fission track analysis

    Institute of Scientific and Technical Information of China (English)

    Wenhao Tang; Zhicheng Zhang; Jianfeng Li; Ke Li; Zhiwen Luo; Yan Chen

    2015-01-01

    Apatite fission track (AFT) analysis on samples collected from a Paleozoic series is used to constrain the cooling history of the Bogda Mountain, northwest China. AFT ages range from 136.2 to 85.6 Ma and are younger than rock depositional ages and the mean confined track lengths (11.0e13.2 mm) mostly showing unimodal distribution are shorten, indicating significant track-annealing. Thermal histories modeling based on the distribution of fission-track lengths combined with the regional geological data show that two rapid cooling phases occurred in the latest Jurassiceearly Cretaceous and the OligoceneeMiocene. Those new data together with previous published data show that the AFT ages become younger from the southwest to northeast in the western Bogda Mountain and its adjacent areas. The fission-track ages of the southwest area are relatively older (>100 Ma), recording the earlier rapid uplift phase during the late JurassiceCretaceous, while the ages in the north pied-mont of the Bogda Mountain (namely the northeast part) are younger (<60 Ma), mainly reflecting the later rapid uplift phase in the OligoceneeMiocene. The trend of younger AFT ages towards the northeast might be explained by post-Cretaceous large-scale crustal tilting towards the southwest. In the thrust fault-dominated northern limbs of the Bogda Mountain, AFT ages reveal a discontinuous pattern with age-jumps across the major fault zones, showing a possible strata tilting across each thrust faults due to the thrust ramps during the Cenozoic. The two rapid uplift stages might be related to the accretion and collision in the southern margin of the Asian continent during the late Jurassic and late Cenozoic, respectively.

  3. The significance of climate change in the Netherlands. An analysis of historical and future trends (1901-2020) in weather conditions, weather extremes and temperature-related impacts

    International Nuclear Information System (INIS)

    A rigorous statistical analysis reveals changes in Dutch climate that are statistically significant over the last century. Annually averaged temperatures have increased by 1.5 about 0.5 degrees Centigrade; the number of summer days has roughly doubled from 14 about 5 to 27 about 9 days; annual precipitation has increased by 120 about 100 mm; and the number of extremely wet days has increased by about 40%, from 19 about 3 to 26 about 3 days. Several other changes in Dutch climate, such as spring temperatures rising more rapidly than winter temperatures, the increase of the coldest temperature in each year by 0.9 degrees Centigrade and the annual maximum day sum of precipitation, turn out to be not (yet) statistically significant. The changes in Dutch climate have already led to several statistically significant impacts. The length of the growing season has increased by nearly a month, and the number of heating-degree days, a measure for the energy needed for the heating of houses and buildings, has decreased by 14 about 5%. Projections of future temperature increase in 2020 based on the statistical analysis closely resemble projections based on climate models: temperatures continue to increase from 10.4 about 0.4 degrees Centigrade in 2003 to 10.7 about 0.6 degrees Centigrade in 2010 and 11.1 about 1.0 degrees Centigrade in 2020. The energy needed for heating of houses and buildings is expected to decrease further. This warming effect is expected to lower projections of future Dutch greenhouse-gas emissions by 3.5 Mton CO2 equivalents, which is relevant in the context of commitments under the Kyoto Protocol. Finally, over the course of the 20th century the chance on an 'Elfstedentocht', an outdoor skating event in the Netherlands, has decreased from once every five years to once every ten years. Even though this impact change is not yet statistically significant, it resides 'on the edge' of significance: within a few years more evidence may become available to

  4. Cenozoic intracontinental deformation of the Kopeh Dagh Belt, Northeastern Iran

    Science.gov (United States)

    Chu, Yang; Wan, Bo; Chen, Ling; Talebian, Morteza

    2016-04-01

    Compressional intracontinental orogens represent large tectonic zones far from plate boundaries. Since intracontinental mountain belts cannot be framed in the conventional plate tectonics theory, several hypotheses have been proposed to account for the formations of these mountain belts. The far-field effect of collision/subduction at plate margins is now well accepted for the origin and evolution of the intracontinental crust thickening, as exemplified by the Miocene tectonics of central Asia. In northern Iran, the Binalud-Alborz mountain belt witnessed the Triassic tectonothermal events (Cimmerian orogeny), which are interpreted as the result of the Paleotethys Ocean closure between the Eurasia and Central Iran blocks. The Kopeh Dagh Belt, located to the north of the Binalud-Alborz Belt, has experienced two significant tectonic phases: (1) Jurassic to Eocene rifting with more than 7 km of sediments; and (2) Late Eocene-Early Oligocene to Quaternary continuous compression. Due to the high seismicity, deformation associated with earthquakes has received more and more attention; however, the deformation pattern and architecture of this range remain poorly understood. Detailed field observations on the Cenozoic deformation indicate that the Kopeh Dagh Belt can be divided into a western zone and an eastern zone, separated by a series of dextral strike-slip faults, i.e. the Bakharden-Quchan Fault System. The eastern zone characterized by km-scale box-fold structures, associated with southwest-dipping reverse faults and top-to-the NE kinematics. In contrast, the western zone shows top-to-the SW kinematics, and the deformation intensifies from NE to SW. In the northern part of this zone, large-scale asymmetrical anticlines exhibit SW-directed vergence with subordinate thrusts and folds, whereas symmetrical anticlines are observed in the southern part. In regard to its tectonic feature, the Kopeh Dagh Belt is a typical Cenozoic intracontinental belt without ophiolites or

  5. ACEX: A First Look at Arctic Ocean Cenozoic History

    Science.gov (United States)

    Moran, K.; Backman, J.

    2004-12-01

    The first Integrated Ocean Drilling Program mission specificplatform expedition (ACEX - Arctic Coring Expedition) drilled and recovered core from five holes at four sites through Cenozoic sediments draping the crest of the Lomonosov Ridge in the central Arctic Ocean. Coring continued into the underlying Cretaceous sedimentary bedrock. Sites are located only a few nautical miles apart along a single seismic line (AWI-91090), showing an identical and coherent Cenozoic seismostratigraphy. Preliminary results from shipboard investigations of core-catcher-based bio- and lithostratigraphy, pore water analyses and core logger data describe a thick (~160 m) middle Miocene through Pleistocene sequence that shows large amplitude, cyclic variability in the density, magnetic susceptibility and acoustic velocity of the sediments. Sediments are largely carbonate free. Pleistocene sedimentation rates are close to 3 cm/ka, whereas Pliocene sediments are by-and-large missing. A sharp change in physical properties at ~200 m defines the transition into a 200+ m thick Paleogene sequence that is initially dominated by large numbers of dinoflagellate cysts. The early Miocene, Oligocene and late Eocene appear to be largely missing in a hiatus. However, a 32 m thick interval separates the overlying middle Miocene from the underlying middle Eocene and presumably preserves some of the early Neogene and late Paleogene sections. Dinoflagellate cysts, diatoms, ebridians and silicoflagellates are common to abundant in the middle Eocene section, which bottoms in a spectacular layer showing massive occurrences of glochidia and massulae (megaspores) of the freshwater hydropterid fern Azolla (duckweed) at the early/middle Eocene boundary (~306 m), suggesting strongly reduced surface water salinity or perhaps even a brief episode of fresh water conditions at the surface. Biosilica is not present prior to the late early Eocene (~320 m). The (sub-) tropical dinoflagellate species Apectodinium augustum

  6. Late Cretaceous and Cenozoic exhumation history of the Malay Peninsula

    Science.gov (United States)

    François, Thomas; Daanen, Twan; Matenco, Liviu; Willingshofer, Ernst; van der Wal, Jorien

    2015-04-01

    The evolution of Peninsular Malaysia up to the collisional period in the Triassic is well described but the evolution since the collision between Indochina and the Sukhothai Arc in Triassic times is less well described in the literature. The processes affecting Peninsular Malaysia during the Jurassic up to current day times have to explain the emplacement multiple intrusions (the Stong Complex, and the Kemahang granite), the Jurassic/Cretaceous onland basins, the Cenozoic offshore basins, and the asymmetric extension, which caused the exhumation of Taku Schists dome. The orogenic period in Permo-Triassic times, which also formed the Bentong-Raub suture zone, resulted in thickening of the continental crust of current day Peninsular Malaysia due to the collision of the Indochina continental block and the Sukhothai Arc, and is related to the subduction of oceanic crust once present between these continental blocks. The Jurassic/Cretaceous is a period of extension, resulting in the onland Jurassic/Cretaceous basins, synchronous melting of the crust, resulting in the emplacement Stong Complex and the Kemahang granite and thinning of the continental crust on the scale of the Peninsular, followed by uplift of the Peninsular. Different models can explain these observations: continental root removal, oceanic slab detachment, or slab delamination. These models all describe the melting of the lower crust due to asthenospheric upwelling, resulting in uplift and subsequent extension either due to mantle convective movements or gravitational instabilities related to uplift. The Cenozoic period is dominated by extension and rapid exhumation in the area as documented by low temperature thermocrological ages The extension in this period is most likely related to the subduction, which resumed at 45 Ma, of the Australian plate beneath the Eurasian plate after it terminated in Cretaceous times due to the collision of an Australian microcontinental fragment with the Sunda margin in the

  7. Trace Element Geochemistry of Cenozoic Volcanic Rocks in Shandong Province

    Institute of Scientific and Technical Information of China (English)

    陈道公; 李彬贤; 等

    1989-01-01

    The Cenozoic volcanic rock of Shandong Province are mainly alkalic and strongly alkalic basaltic rocks.The Contents of major and trace elements including transitional,incompatible and rare-earth elements were determined.The chemical characterisitics of major and trace elements indicate that these basaltic rocks were derived from a mantle source and probably represent a primary magma,I,e.,unmodifiecd partical melts of mantle peridotite in terms of Mg values,correlatione between P2O5 and Ce,Sr,Ni and Rb concentrations,mantle xenoliths,etc.The abundances of trace elements vary systematically from west to east.The compatible transition elements such as Co,Ni,and Cr show a remarkable depletion,whereas the incompatible and rare-earth elements are abundant as viewed from the chondrite-nor-malized patterns.The chemical composition and correlation are consistent with the tectonic setting.According to the batch and fractional partial melting theory,the trace element contents of Shandong volcanic rocks can be calculated from the two-component mixing model.

  8. Successor Characteristics of the Mesozoic and Cenozoic Songliao Basins

    Institute of Scientific and Technical Information of China (English)

    LI Zhongquan; Timothy KUSKY; YING Danlin; GUO Xiaoyu; LI Hongkui

    2008-01-01

    The Songliao basin is a complex successor basin that was initiated in the Mesozoic and experienced multiple periods of reactivation. Based on seismic and drilling data, as well as regional geologic research, we suggest that the Songliao basin contains several different successor basins resting on top of Carboniferous-Permian folded strata forming the basement to the Songliao basin. These basins include the Triassic-Mid Jurassic Paleo-foreland basin, the Late Jurassic-Early Cretaceous downfaulted basin, and an early Cretaceous depressed basin (since the Denglouku Group). This paper presents a systematic study of the basin-mountain interactions, and reveals that there are different types of prototype basin at different geologic times. These prototype basins sequentially superimposed and formed the large Songliao basin. Discovery of the Triassic-early Middle Jurassic paleo-foreland basin fills a Triassic-early Middle Jurassic gap in the geologic history of the Songliao basin. The paleoforeland basin, downfaulted basin, and depressed thermal subsidence basin all together represent the whole Mesozoic-Cenozoic geologic history and deformation of the Songliao basin. Discovery of the Triassic-early Middle Jurassic paleo-foreland basin plays an important role both for deep natural gas exploration and the study of basin-mountain coupling in north China and eastern China in general. This example gives dramatic evidence that we should give much more attention to the polyphase tectonic evolution of related basins for the next phase of exploration and study.

  9. Continental erosion and the Cenozoic rise of marine diatoms

    Science.gov (United States)

    Cermeño, Pedro; Falkowski, Paul G.; Romero, Oscar E.; Schaller, Morgan F.; Vallina, Sergio M.

    2015-04-01

    Marine diatoms are silica-precipitating microalgae that account for over half of organic carbon burial in marine sediments and thus they play a key role in the global carbon cycle. Their evolutionary expansion during the Cenozoic era (66 Ma to present) has been associated with a superior competitive ability for silicic acid relative to other siliceous plankton such as radiolarians, which evolved by reducing the weight of their silica test. Here we use a mathematical model in which diatoms and radiolarians compete for silicic acid to show that the observed reduction in the weight of radiolarian tests is insufficient to explain the rise of diatoms. Using the lithium isotope record of seawater as a proxy of silicate rock weathering and erosion, we calculate changes in the input flux of silicic acid to the oceans. Our results indicate that the long-term massive erosion of continental silicates was critical to the subsequent success of diatoms in marine ecosystems over the last 40 My and suggest an increase in the strength and efficiency of the oceanic biological pump over this period.

  10. Late Cenozoic sedimentary and tectonic history of south Buton, Indonesia

    Science.gov (United States)

    Fortuin, A. R.; De Smet, M. E. M.; Hadiwasastra, S.; Van Marle, L. J.; Troelstra, S. R.; Tjokrosapoetro, S.

    A description and interpretation are given of the Upper Cenozoic sedimentary record of south Buton. Various sections and outcrops were studied and sampled for their microfossil content, to provide age and paleobathymetrical data. Together with information from the literature, these data from the base for a geohistory analysis to evaluate the vertical motions. Deposition started some 11 Ma ago, after the main deformation of the island, which was related to the collision of a microplate carrying Buton, with the southeast arm of Sulawesi. Coarse and fine terrigenous debris accumulated in a rapidly subsiding foreland basin; subsidence may have exceeded 100 cm/ka. When the rate of subsidence decreased a late Miocene-early Pliocene period of quiet pelagic sedimentation followed. From the late Pliocene onwards (around 3.5 Ma BP) an overall uplift took place, with rates between 30-120 cm/ka. This drastic change is explained by the collision of Buton with a submerged microcontinent that presently forms the Tukang Besi platform, situated southeast of Buton, which interaction resulted in wrench type tectonics and a clockwise rotation of over 60° for south Buton.

  11. Mid Cenozoic freshwater wetlands of the Sunda region

    Directory of Open Access Journals (Sweden)

    Robert J. Morley

    2013-08-01

    Full Text Available The Sunda region was the scene of widespread rifting during the mid-Cenozoic, resulting in the development of numerous large lake-filled rifts, analogous in scale to the rift valley system of East Africa. The Tonle Sap in Cambodia forms the closest modern analogue for these lakes in the Southeast Asian region. Many of the palaeolakes were long lived, continuing uninterrupted as open lakes for several millions of years during the Oligocene. Smaller rift systems infilled with fluvial sediments, but the larger ones remained as lakes, and with Late Oligocene subsidence, were transformed by brackish, and in the earliest Miocene, by marine incursion, into large inland seas. These seas reached their greatest extent at the time of the mid Miocene thermal maximum. This paper describes the development and eventual demise of these lakes following marine transgression, and, based on their rich content of pollen and spores, illustrates the variety of fresh and brackish water swamp communities which developed around their margins. The marginal swamps can be divided into: i seasonally inundated swamps, mainly during the Oligocene, characterised by Barringtonia, Lagerstroemia and grasses/sedges; ii fern swamps and iii from the Late Oligocene onward alluvial swamps, often characterised by Pandanus; and iv peat swamps. The latter can be differentiated into kerapah peat swamps, first occurring during the Oligocene, and basinal peat swamps, becoming widespread from the Early Miocene onward.

  12. Meso-Cenozoic Source-to-Sink analysis of the African margin of the Equatorial Atlantic

    Science.gov (United States)

    Chardon, Dominique; Rouby, Delphine; Huyghe, Damien; Ye, Jing; Guillocheau, François; Robin, Cécile; Dall'Asta, Massimo; Brown, Roderick; Webster, David

    2015-04-01

    The Transform Source to Sink Project (TS2P) objective is to link the evolution of the offshore sedimentary basins of the African margin of the Equatorial Atlantic and their source areas on the West African Craton. The margin consists in alternating transform and oblique margin portions from Guinea, in the West, to Nigeria, in the East. Such a longitudinal structural variability is associated with variation in the margin width, continental geology and relief, drainage networks and subsidence/accumulation patterns that we analyzed using offshore seismic data and onshore geology and geomorphology. We compare syn- to post rift offshore geometry and long-term stratigraphic history of each of the margin segments. Transform faults appear to play a major role in shaping Early Cretaceous syn-rift basin architectures. Immediate post-rift Late Cretaceous sedimentary wedges record a transgression and are affected by the reactivation of some of transform faults. We produced A new type of inland paleogeographic maps for key periods since the end of the Triassic, allowing delineation of intracratonic basins having accumulated material issued from erosion of the marginal upwarps that have grown since break-up along the margin. We use offshore and onshore basin analysis to estimate sediment accumulation and integrate it in a source-to-sink analysis where Mesozoic onshore denudation will be estimated by low-temperature thermochronology. Cenozoic erosion and drainage history of the continental domain have been reconstructed from the spatial analysis of dated and regionally correlated geomorphic markers. The stationary drainage configuration of the onshore domain since 30 Ma offers the opportunity to correlate the detailed onshore morphoclimatic record based on the sequence of lateritic paleolandsurfaces to offshore stratigraphy, eustasy and global climatic proxies since the Oligocene. Within this framework, we simulate quantitative solute / solid erosional fluxes based on the

  13. Trend of Sandstorm in the Manas River Basin Oasis and Its Correlation with Climatic Factors%玛纳斯河流域绿洲沙尘暴趋势及其与气候因子的关系

    Institute of Scientific and Technical Information of China (English)

    凌红波; 徐海量; 张青青

    2011-01-01

    利用玛纳斯河流域绿洲区3个气象站1959-2007年的气象资料,借助小波分析、混沌理论、R/S分析和非参数检验等方法,分析沙尘暴频数的趋势、周期、混沌特性以及气候因子对沙尘暴的影响。结果表明:玛纳斯河流域绿洲沙尘暴频数呈减少趋势,并集中于春、夏两季;该流域绿洲沙尘暴频数存在明显的4年和17年周期性变化;根据R/S分析,流域沙尘暴频数在未来的15年仍保持减少趋势;1959-2007年,流域内沙尘暴、蒸发量和大风日数减少趋势明显,且关联显著,而气温、降水量与最大日降水量表现为升高和增加走势,且关联性较差;流域绿洲沙尘暴频数与NAO指数在夏季存在显著的关联性。%The trends,periods and chaotic characteristics of sandstorm and the impacts of climatic factors on sandstorm variation were analyzed based on the meteorological data observed by 3 weather stations in the Manas River Bain oasis during the period of 1959-2007 and using the methods of wavelet analysis,chaotic theory,R/S analysis and nonparametric test.The results show that the sandstorm frequency was in a decrease trend,and sandstorm occurred mainly in spring and summer;there were the 4-year and 17-year periodic changes of sandstorm frequency in the Manas River Basin oasis;based on the R/S analysis,it is believable to predict that the decrease trend of sandstorm frequency will still maintained in next 15 years;there were the significant correlations between sandstorm and evaporation and gale,but the correlations between sandstorm and other climatic factors were not significant;the sandstorm is closely and significantly correlated with the NAO in summer.

  14. Impact of climate change and man-made irrigation systems on the transmission risk, long-term trend and seasonality of human and animal fascioliasis in Pakistan

    Directory of Open Access Journals (Sweden)

    Kiran Afshan

    2014-05-01

    Full Text Available Large areas of the province of Punjab, Pakistan are endemic for fascioliasis, resulting in high economic losses due to livestock infection but also affecting humans directly. The prevalence in livestock varies pronouncedly in space and time (1-70%. Climatic factors influencing fascioliasis presence and potential spread were analysed based on data from five mete- orological stations during 1990-2010. Variables such as wet days (Mt, water-budget-based system (Wb-bs indices and the normalized difference vegetation index (NDVI, were obtained and correlated with geographical distribution, seasonality patterns and the two-decade evolution of fascioliasis in livestock throughout the province. The combined approach by these three indices proved to furnish a useful tool to analyse the complex epidemiology that includes (i sheep-goats and cattle- buffaloes presenting different immunological responses to fasciolids; (ii overlap of Fasciola hepatica and F. gigantica; (iii co-existence of highlands and lowlands in the area studied; and (iv disease transmission following bi-seasonality with one peak related to natural rainfall and another peak related to man-made irrigation. Results suggest a human infection situa- tion of concern and illustrate how climate and anthropogenic environment modifications influence both geographical dis- tribution and seasonality of fascioliasis risks. Increased fascioliasis risk throughout the Punjab plain and its decrease in the northern highlands of the province became evident during the study period. The high risk in the lowlands is worrying given that Punjab province largely consists of low-altitude, highly irrigated plains. The importance of livestock in this province makes it essential to prioritise adequate control measures. An annual treatment scheme to control the disease is recom- mended to be applied throughout the whole province.

  15. A major reorganization of Asian climate regime by the early Miocene

    OpenAIRE

    Z. T. Guo; Sun, B; Z. S. Zhang; Peng, S. Z.; G. Q. Xiao; Ge, J. Y.; Q. Z. Hao; Qiao, Y. S.; M. Y. Liang; Liu, J F; Q. Z. Yin; Wei, J. J.

    2008-01-01

    The global climate system has experienced a series of drastic changes during the Cenozoic. These include the climate transformation in Asia, from a zonal pattern to a monsoon-dominant pattern, the disappearance of subtropical aridity related to a planetary circulation system and the onset of inland deserts in central Asia. Despite of the major advances in the last two decades in characterizing and understanding these climate phenomena, disagreements persi...

  16. Climate change

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    This paper presented indicators of climate change for British Columbia (BC) with an emphasis on the coastal region. An overview of global effects of climate change was presented, as well as details of BC's current climate change action plan. Indicators examined in the paper for the BC coastal region included long-term trends in air temperature; long-term trends in precipitation; coastal ocean temperatures; sea levels on the BC coast; and the sensitivity of the BC coast to sea level rise and erosion. Data suggested that average air temperatures have become higher in many areas, and that Springtime temperatures have become warmer over the whole province. Winters have become drier in many areas of the province. Sea surface temperature has risen over the entire coast, with the North Coast and central Strait of Georgia showing the largest increases. Deep-water temperatures have also increased in 5 inlets on the South Coast. Results suggested that the direction and spatial pattern of the climate changes reported for British Columbia are consistent with broader trends in North America and the type of changes predicted by climate models for the region. Climate change will likely result in reduced snow-pack in southern BC. An earlier spring freshet on many snow-dominated river systems is anticipated as well as glacial retreat and disappearance. Warmer temperatures in some lakes and rivers are expected, as well as the increased frequency and severity of natural disturbances such as the pine mountain beetle. Large-scale shifts in ecosystems and the loss of certain ecosystems may also occur. BC's current climate plan includes cost effective actions that address GHG emissions and support efficient infrastructure and opportunities for innovation. Management programs for forest and agricultural lands have been initiated, as well as programs to reduce emissions from government operations. Research is also being conducted to understand the impacts of climate change on

  17. Climate change

    International Nuclear Information System (INIS)

    This paper presented indicators of climate change for British Columbia (BC) with an emphasis on the coastal region. An overview of global effects of climate change was presented, as well as details of BC's current climate change action plan. Indicators examined in the paper for the BC coastal region included long-term trends in air temperature; long-term trends in precipitation; coastal ocean temperatures; sea levels on the BC coast; and the sensitivity of the BC coast to sea level rise and erosion. Data suggested that average air temperatures have become higher in many areas, and that Springtime temperatures have become warmer over the whole province. Winters have become drier in many areas of the province. Sea surface temperature has risen over the entire coast, with the North Coast and central Strait of Georgia showing the largest increases. Deep-water temperatures have also increased in 5 inlets on the South Coast. Results suggested that the direction and spatial pattern of the climate changes reported for British Columbia are consistent with broader trends in North America and the type of changes predicted by climate models for the region. Climate change will likely result in reduced snow-pack in southern BC. An earlier spring freshet on many snow-dominated river systems is anticipated as well as glacial retreat and disappearance. Warmer temperatures in some lakes and rivers are expected, as well as the increased frequency and severity of natural disturbances such as the pine mountain beetle. Large-scale shifts in ecosystems and the loss of certain ecosystems may also occur. BC's current climate plan includes cost effective actions that address GHG emissions and support efficient infrastructure and opportunities for innovation. Management programs for forest and agricultural lands have been initiated, as well as programs to reduce emissions from government operations. Research is also being conducted to understand the impacts of climate change on water

  18. Latitudinal-Related Variation in Wintering Population Trends of Greylag Geese (Anser Anser) along the Atlantic Flyway: A Response to Climate Change?

    Science.gov (United States)

    Ramo, Cristina; Amat, Juan A.; Nilsson, Leif; Schricke, Vincent; Rodríguez-Alonso, Mariano; Gómez-Crespo, Enrique; Jubete, Fernando; Navedo, Juan G.; Masero, José A.; Palacios, Jesús; Boos, Mathieu; Green, Andy J.

    2015-01-01

    The unusually high quality of census data for large waterbirds in Europe facilitates the study of how population change varies across a broad geographical range and relates to global change. The wintering population of the greylag goose Anser anser in the Atlantic flyway spanning between Sweden and Spain has increased from 120 000 to 610 000 individuals over the past three decades, and expanded its wintering range northwards. Although population sizes recorded in January have increased in all seven countries in the wintering range, we found a pronounced northwards latitudinal effect in which the rate of increase is higher at greater latitudes, causing a constant shift in the centre of gravity for the spatial distribution of wintering geese. Local winter temperatures have a strong influence on goose numbers but in a manner that is also dependent on latitude, with the partial effect of temperature (while controlling for the increasing population trend between years) being negative at the south end and positive at the north end of the flyway. Contrary to assumptions in the literature, the expansion of crops exploited by greylag geese has made little contribution to the increases in population size. Only in one case (expansion of winter cereals in Denmark) did we find evidence of an effect of changing land use. The expanding and shifting greylag population is likely to have increasing impacts on habitats in northern Europe during the course of this century. PMID:26465601

  19. Projected loss of soil organic carbon in temperate agricultural soils in the 21(st) century: effects of climate change and carbon input trends.

    Science.gov (United States)

    Wiesmeier, Martin; Poeplau, Christopher; Sierra, Carlos A; Maier, Harald; Frühauf, Cathleen; Hübner, Rico; Kühnel, Anna; Spörlein, Peter; Geuß, Uwe; Hangen, Edzard; Schilling, Bernd; von Lützow, Margit; Kögel-Knabner, Ingrid

    2016-01-01

    Climate change and stagnating crop yields may cause a decline of SOC stocks in agricultural soils leading to considerable CO2 emissions and reduced agricultural productivity. Regional model-based SOC projections are needed to evaluate these potential risks. In this study, we simulated the future SOC development in cropland and grassland soils of Bavaria in the 21(st) century. Soils from 51 study sites representing the most important soil classes of Central Europe were fractionated and derived SOC pools were used to initialize the RothC soil carbon model. For each site, long-term C inputs were determined using the C allocation method. Model runs were performed for three different C input scenarios as a realistic range of projected yield development. Our modelling approach revealed substantial SOC decreases of 11-16% under an expected mean temperature increase of 3.3 °C assuming unchanged C inputs. For the scenario of 20% reduced C inputs, agricultural SOC stocks are projected to decline by 19-24%. Remarkably, even the optimistic scenario of 20% increased C inputs led to SOC decreases of 3-8%. Projected SOC changes largely differed among investigated soil classes. Our results indicated that C inputs have to increase by 29% to maintain present SOC stocks in agricultural soils. PMID:27585648

  20. What were the biological and climatic effects of the Australasian impact event

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Wuchang; Peleo-Alampay, A. (Univ. of California, San Diego, CA (United States). Scripps Inst. Oceanography); Wise, S.W. (Florida State Univ., Tallahassee, FL (United States). Dept. of Geology)

    1993-03-01

    The Australasian microtektites, which are now generally accepted as the products of extraterrestrial impacts, occur near the Brunhes/Matuyama boundary at about 0.75 Ma and have a wide distribution ([approximately]10% of the earth's surface). This impact event is the second largest in the Cenozoic, and the impact crater has been estimated to be about 17 km. In order to better understand the role of impacts in shaping life and climate on earth, the authors carried out a detailed study of nannofossils across the Australasian microtektite interval at ODP site 758 in the equatorial Indian Ocean. They also compiled high-resolution stable isotope and carbonate data from this site and others to infer paleoclimate conditions across this interval. The study indicates that there is no calcareous nannoplankton extinction associated with the impact horizon. There is also no significant change in the abundance of Florisphaera profound, an environmentally sensitive species. Carbonate content shows little variation across the impact horizon, which suggests that ocean productivity did not change significantly. Oxygen isotope data show typical Pleistocene glacial-interglacial cycles, which were generally caused by the Milankovitch cycles. The impact horizon is located slightly after the glacial maximum in oxygen isotope stage 20. In other words, the impact was within a warming trend from glacial stage 20 to interglacial stage 19. They conclude that, within the resolution of the geologic records ([approximately]1,000 yrs), the Australasian impact had insignificant effects on life and climate.

  1. Late Cenozoic structure and stratigraphy of south-central Washington

    International Nuclear Information System (INIS)

    The structural framework of the Columbia Basin began developing before Columbia River Basalt Group (CRBG) volcanism. Prior to 17.5 Ma, the eastern part of the basin was a relatively stable area, with a basement of Paleozoic and older crystalline rock. The western part was an area of subsidence in which large volumes of sediment and volcanic rocks accumulated. Concurrent with eruption of the CRBG, anticlinal ridges of the Yakima Fold Belt (YFB) were growing under north-south compression. Topographic expression of these features was later masked by the large volume of CRBG basalt flowing west from fissures in the eastern Columbia Basin. The folds continued to develop after cessation of volcanism, leading to as much as 1,000 m of structural relief in the past 10 million years. Post-CRBG evolution of the Columbia Basin is recorded principally in folding and faulting in the YFB and sediments deposited in the basins. The accompanying tectonism resulted in lateral migration of major depositional systems into subsiding structural lows. Although known late Cenozoic faults are on anticlinal ridges, earthquake focal mechanisms and contemporary strain measurements indicate most stress release is occurring in the synclinal areas under north-south compression. There is no obvious correlation between focal mechanisms for earthquakes whose foci are in the CRBG and the location of known faults. High in situ stress values help to explain the occurrence of microseismicity in the Columbia Basin but not the pattern. Microseismicity appears to occur in unaltered fresh basalt. Faulted basalt associated with the YFB is highly brecciated and commonly altered to clay. The high stress, abundance of ground water in confined aquifers of the CRBG, and altered basalt in fault zones suggest that the frontal faults on the anticlinal ridges probably have some aseismic deformation. 85 refs

  2. Improving the Ginkgo CO2 barometer: Implications for the early Cenozoic atmosphere

    Science.gov (United States)

    Barclay, Richard S.; Wing, Scott L.

    2016-04-01

    Stomatal properties of fossil Ginkgo have been used widely to infer the atmospheric concentration of CO2 in the geological past (paleo-pCO2). Many of these estimates of paleo-pCO2 have relied on the inverse correlation between pCO2 and stomatal index (SI - the proportion of epidermal cells that are stomata) observed in recent Ginkgo biloba, and therefore depend on the accuracy of this relationship. The SI - pCO2 relationship in G. biloba has not been well documented, however. Here we present new measurements of SI for leaves of G. biloba that grew under pCO2 from 290 to 430 ppm. We prepared and imaged all specimens using a consistent procedure and photo-documented each count. As in prior studies, we found a significant inverse relationship between SI and pCO2, however, the relationship is more linear, has a shallower slope, and a lower correlation coefficient than previously reported. We examined leaves of G. biloba grown under pCO2 of 1500 ppm, but found they had highly variable SI and a large proportion of malformed stomata. We also measured stomatal dimensions, stomatal density, and the carbon isotope composition of G. biloba leaves in order to test a mechanistic model for inferring pCO2. This model overestimated observed pCO2, performing less well than the SI method between 290 and 430 ppm. We used our revised SI-pCO2 response curve, and new observations of selected fossils, to estimate late Cretaceous and Cenozoic pCO2 from fossil Ginkgo adiantoides. All but one of the new estimates is below 800 ppm, and together they show little long-term change in pCO2 or relation to global temperature. The low Paleogene pCO2 levels indicated by the Ginkgo SI proxy are not consistent with the high pCO2 inferred by some climate and carbon cycle models. We cannot currently resolve the discrepancy, but greater agreement between proxy data and models may come from a better understanding of the stomatal response of G. biloba to elevated pCO2, better counts and measurements of

  3. Processing trends

    International Nuclear Information System (INIS)

    This paper identifies trends associated with the performance of automatic film processors in hospitals and nonhospital facilities, including chiropractic facilities. Automatic film processors were evaluated in more than 1,700 facilities as a part of the Nationwide Evaluation of x-ray Trends (NEXT) program. Processing was evaluated with use of the Sensitometric Technique for Evaluation of Processing (STEP) procedure, which involves the exposure of control film to a calibrated light sensitometer and evaluation of the resultant film density. A processing speed index of 100 means that the processor is processing films according to the film manufacturers' normal recommended specifications; deviation from this value suggest underprocessing or overprocessing conditions

  4. Two Cenozoic tectonic events of N-S and E-W extension in the Lhasa Terrane: Evidence from geology and geochronology

    Science.gov (United States)

    Huang, Feng; Xu, Ji-Feng; Chen, Jian-Lin; Wu, Jian-Bin; Zeng, Yun-Chuan; Xiong, Qiu-Wei; Chen, Xue-Feng; Yu, Hong-Xia

    2016-02-01

    Cenozoic active structures in the Tibetan Plateau are mainly regional N-S trending extensional faults and grabens, and E-W trending extensional tracks that are related to the transition from syn- to post-collision between India and Asia. E-W trending tracks are parallel to the direction of Neo-Tethyan oceanic convergence and consist of extensional volcanic-sedimentary basins and magmatic dykes in the southern Lhasa Terrane, Tibet. N-S trending tracks comprise faults and grabens, which are widely developed in Tibet. It remains unknown how and when the geodynamic transition from E-W to N-S trending tectonic tracks occurred. This study describes both E-W and N-S trending tectonic tracks identified at Dazi area of southern Lhasa Terrane, where E-W trending mafic dykes intruded a granitoid and late-stage N-S trending felsic dykes cut across E-W trending mafic dykes. Zircons from four granitoid samples yield consistent crystallization ages of ca. 60 Ma and positive εHf(t) values (~+ 9). An altered dioritic vein, which cuts the mafic dykes, yields an age of ca. 53 Ma. These new dating results indicate that E-W trending dykes, which formed due to regional N-S extension, were emplaced between 60 and 53 Ma. In addition, two N-S trending monzonitic porphyritic dykes, which cut the mafic dykes, yield U-Pb zircon ages of ca. 17 Ma with moderate positive εHf(t) values (+ 3 to + 9.6), as well as a NNE-SSW trending quartz monzonitic dyke, which cuts all other types of dykes, yields U-Pb ages of ca. 13 Ma. This suggests that E-W extension took place between 17 and 13 Ma. These results, in combination with existing age data for Gangdese granitoids and mafic magmatism, indicate the occurrence of two major extensional events at 60-53 Ma and 17-13 Ma. In turn, this implies that the transition from E-W to N-S trending tectonic and the onset of E-W extension occurred at ca. 17 Ma or slightly earlier. Paleocene granitoids have geochemical characteristics that are indicative of both

  5. The implication for climate change and peak fossil fuel of the continuation of the current trend in wind and solar energy production

    International Nuclear Information System (INIS)

    Climate change, and more recently, the risk of fossil fuel production being unable to keep pace with demand (peak fossil fuel) are both considered as risks to civilisation, or global risks. In an initial empirical analysis, this paper attempts to answer the following questions, which have often been posed but have not, to our knowledge, been answered empirically at global level. At which date, if unaddressed, will the risks become critical? Given that the substitution of fossil fuels by wind and solar energy is often proposed as a solution to these problems, what is its current aggregate growth rate and is there a plausible future growth rate which would substitute it for fossil fuels before the risks become critical? The study finds that the peak fossil fuel risk will start to be critical by 2020. If however the future growth rate of wind and solar energy production follows that already achieved for the world mobile phone system or the Chinese National Expressway Network the peak fossil fuel risk can be prevented completely. For global warming, the same growth rate provides significant mitigation by reducing carbon dioxide emissions from fossil fuels to zero by the early 2030s. - Highlights: ► Converging studies show the peak fossil fuel risk likely to be critical by 2020. ► We model the future growth rate of wind and solar energy based on analogous precedents. ► These are the growth rates already achieved by the world mobile phone system and the Chinese National Expressway Network. ► We show that wind and solar energy growth at these rates averts the peak fossil fuel risk. ► For global warming, the scenarios make fossil-fuel CO2 emissions zero by 2030.

  6. Aeromagnetic search for Cenozoic magmatism over the Admiralty Mountains Block (East Antarctica)

    Science.gov (United States)

    Armadillo; E.; Ferraccioli, F.; Zunino, A.; Bozzo, E.; Rocchi, S.; Armienti, P.

    2007-01-01

    Cenozoic magmatic rocks of the Transantarctic Mountains provide an important window on the tectonic and magmatic processes of the West Antarctic Rift System. Previous aeromagnetic investigations in northern Victoria Land have delineated Cenozoic volcanic and intrusive complexes assigned to the McMurdo Volcanic Group and Meander Intrusives over the Transantarctic Mountains. We present a new aeromagnetic anomaly map for the region north of the Mariner Glacier to study the extent and spatial distribution of these Cenozoic rocks over the previously unexplored Admiralty Mountains. The new map shows that the Meander Intrusives are restricted to the coastal region between the Malta Plateau and the Daniell Peninsula. However, the McMurdo Volcanic Group rocks extend further inland, and may delineate a hitherto unrecognised volcano-tectonic rift zone, extending as far north as the Trafalgar Glacier.

  7. Long-term changes in the composition and diversity of deep-slope megabenthos and trophic webs off Catalonia (western Mediterranean): Are trends related to climatic oscillations?

    Science.gov (United States)

    Cartes, J. E.; Maynou, F.; Fanelli, E.; Papiol, V.; Lloris, D.

    2009-07-01

    oceanographic processes and abundance of benthopelagic predators. A conceptual model is presented relating changes in climatic conditions with changes in deep-sea, benthic-suprabenthic food webs. Calocari macandreae was more abundant in 2007, after 3 years of negative NAO. Under negative/low NAO, rainfall and river discharges increase in the NW Mediterranean, which may enhance advective food inputs for macrobenthos. This fits well with the higher abundance of benthos feeders in 2007, as well as with the significant deepening of decapod crustacean assemblages in that same period. Suprabenthos, being short-lived and annual species, were more abundant under positive NAO conditions (1988-1992), probably enhancing the abundance or aggregation of suprabenthic/pelagic feeders.

  8. Review of Climate Scenarios

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Concept and application requirements of climate scenarios were introduced briefly,meanwhile,progresses on theoretical and applied aspects of climate scenarios creation techniques were discussed systematically.Two methods on predicted regional climate changing scenarios,elevating the spatial resolution output and downscaling method,could retrieve the insufficiencies respectively.And the statistical-dynamical downscaling method will be an important developing trend in the developing of downscaling techniques.

  9. The Cenozoic geological evolution of the Central and Northern North Sea based on seismic sequence stratigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Jordt, Henrik

    1996-03-01

    This thesis represents scientific results from seismic sequence stratigraphic investigations. These investigations and results are integrated into an ongoing mineralogical study of the Cenozoic deposits. the main results from this mineralogical study are presented and discussed. The seismic investigations have provided boundary conditions for a forward modelling study of the Cenozoic depositional history. Results from the forward modelling are presented as they emphasise the influence of tectonics on sequence development. The tectonic motions described were important for the formation of the large oil and gas fields in the North Sea.

  10. Early Cenozoic tropical climate: report from the Tanzania Onshore Paleogene Integrated Coring (TOPIC) workshop

    Science.gov (United States)

    Pearson, P. N.; Hudson, W.

    2014-12-01

    We are currently developing a proposal for a new International Continental Scientific Drilling Program (ICDP) project to recover a stratigraphic and paleoclimatic record from the full succession of Eocene hemipelagic sediments that are now exposed on land in southern Tanzania. Funding for a workshop was provided by ICDP, and the project was advertised in the normal way. A group of about 30 delegates assembled in Dar-es-Salaam for 3 intensive days of discussion, project development, and proposal writing. The event was hosted by the Tanzania Petroleum Development Corporation (TPDC) and was attended by several geologists, geochemists, geophysicists, and micropaleontologists from TPDC and the University of Dar-es-Salaam. International delegates were from Canada, Germany, India, Ireland, Italy, the Netherlands, United Kingdom, and United States (and we also have project partners from Australia, Belgium, and Sweden who were not able to attend). Some of the scientists are veterans of previous scientific drilling in the area, but over half are new on the scene, mostly having been attracted by Tanzania's reputation for world-class paleoclimate archives. Here we outline the broad aims of the proposed drilling and give a flavor of the discussions and the way our proposal developed during the workshop. A video of the workshop with an introduction to the scientific goals and interviews of many of the participants is available at http://vimeo.com/107911777.

  11. Shallow gas in Cenozoic sediments of the Southern North Sea

    Science.gov (United States)

    Trampe, Anna F.; Lutz, Rüdiger; Franke, Dieter; Thöle, Hauke; Arfai, Jashar

    2013-04-01

    Shallow petroleum systems in the southern North Sea are known for several decades but they were not actively explored for a long time. In recent years these unconventional shallow petroleum systems are studied in greater detail and one shallow gas field (A-12) is in production in the Netherlands. Additionally, oil was encountered in Miocene sandstones in the southern Danish North Sea (Lille John well) just north of the Danish-German border. Seismic amplitude anomalies are an indication for hydrocarbons in sediments. Therefore we have mapped the occurrence of seismic amplitude anomalies in the German North Sea based on more than 25.000 km of 2D seismic data and around 4.000 km2 of 3D seismic data. Amplitude anomalies are ubiquitous phenomena in the study area. These anomalies are not only caused by hydrocarbons but also by changing lithologies e.g. peat or fluid migration. Therefore several classes of seismic anomalies, e.g. bright spots, chimneys, blanking areas and velocity pull-down were mapped. Examples for these classes were studied with AVO (amplitude variation with offset) analyses to verify the existence or non-existence of gas in the sediments. Shallow gas can be produced and transported through the dense pipeline grid of the southern and central North Sea or it could be burned offshore close to wind parks in small power plants and the electric energy then transported through the existing power connections of the wind parks. Thus enabling a continuous energy supply during calm wind periods. This study is carried out within the framework of the project "Geoscientific Potential of the German North Sea (GPDN)" in which the Cenozoic sedimentary system was mapped in great detail. A detailed model of delta evolution (Baltic river system) was developed which serves as a structural framework. The studied interval is time equivalent to the Utsira formation which is used offshore Norway for sequestration of CO2. These different possibilities of using or exploiting

  12. Reconstructing geographical boundary conditions for palaeoclimate modelling during the Cenozoic

    Science.gov (United States)

    Baatsen, Michiel; van Hinsbergen, Douwe J. J.; von der Heydt, Anna S.; Dijkstra, Henk A.; Sluijs, Appy; Abels, Hemmo A.; Bijl, Peter K.

    2016-08-01

    Studies on the palaeoclimate and palaeoceanography using numerical model simulations may be considerably dependent on the implemented geographical reconstruction. Because building the palaeogeographic datasets for these models is often a time-consuming and elaborate exercise, palaeoclimate models frequently use reconstructions in which the latest state-of-the-art plate tectonic reconstructions, palaeotopography and -bathymetry, or vegetation have not yet been incorporated. In this paper, we therefore provide a new method to efficiently generate a global geographical reconstruction for the middle-late Eocene. The generalised procedure is also reusable to create reconstructions for other time slices within the Cenozoic, suitable for palaeoclimate modelling. We use a plate-tectonic model to make global masks containing the distribution of land, continental shelves, shallow basins and deep ocean. The use of depth-age relationships for oceanic crust together with adjusted present-day topography gives a first estimate of the global geography at a chosen time frame. This estimate subsequently needs manual editing of areas where existing geological data indicate that the altimetry has changed significantly over time. Certain generic changes (e.g. lowering mountain ranges) can be made relatively easily by defining a set of masks while other features may require a more specific treatment. Since the discussion regarding many of these regions is still ongoing, it is crucial to make it easy for changes to be incorporated without having to redo the entire procedure. In this manner, a complete reconstruction can be made that suffices as a boundary condition for numerical models with a limited effort. This facilitates the interaction between experts in geology and palaeoclimate modelling, keeping reconstructions up to date and improving the consistency between different studies. Moreover, it facilitates model inter-comparison studies and sensitivity tests regarding certain

  13. Performance of climate envelope models in retrodicting recent changes in bird population size from observed climatic change

    OpenAIRE

    Green, Rhys E.; Collingham, Yvonne C.; Willis, Stephen G; Gregory, Richard D; Smith, Ken W.; Huntley, Brian

    2008-01-01

    Twenty-five-year population trends of 42 bird species rare as breeders in the UK were examined in relation to changes in climatic suitability simulated using climatic envelope models. The effects of a series of potential ‘nuisance’ variables were also assessed. A statistically significant positive correlation was found across species between population trend and climate suitability trend. The demonstration that climate envelope models are able to retrodict species' population trends provides ...

  14. Cenozoic Seawater Sr/Ca ratios: Implications for coral reef development through ocean de-acidification

    Science.gov (United States)

    Sosdian, S. M.; Grossman, E. L.; Lear, C. H.; Tao, K.; Rosenthal, Y.

    2010-12-01

    Records of seawater chemistry help constrain the temporal variation in geochemical processes that impact the global carbon cycle and global climate across Earth’s history. To date, various attempts to reconstruct Cenozoic seawater Sr/Ca ratios have produced markedly different results, with estimated Paleogene seawater Sr/Ca ranging from ~50% higher than today to 70% lower. We reconstruct seawater Sr/Ca using Eocene to Pliocene fossil mollusks collected from US Gulf Coast (Mississippi, Alabama, and Florida). We use Conus spp. and Turritella, taxa for which the Sr/Ca distribution coefficients have been determined as a function of temperature in modern specimens [1, 2]. Specimens were serially sampled perpendicular to growth to produce seasonal records of Sr/Ca. Fossil Conus shells show pronounced seasonal Sr/Ca cycles with a strong inverse correlation between Sr/Ca and δ18O, similar to those observed in modern specimens [1]. The fossil Turritella also show similar Sr/Ca cyclicity as modern specimens [2]. We calculate seawater Sr/Ca ratios using our Sr/Ca record, modern Sr/Ca-temperature calibrations for Conus and Turritella [1, 2], and a paleotemperature record based on oxygen isotopes from the same samples [3]. Seawater Sr/Ca increased from ~11.5 to 13.9 mmol/mol between the mid-Eocene (42 Ma) and early Oligocene (33 Ma) and decreased substantially from the mid-Miocene (11 mmol/mol) to the Pliocene (9 mmol/mol) and modern (8.5 mmol/mol). A mass balance model of variations in seawater Sr concentrations suggests a long-term decrease through the Neogene, which we attribute to a significant increase in the proportion of aragonite versus calcite deposition in shallow waters. The largest change is coincident with the proliferation of coral reefs, which occurred after the calcite-aragonite sea transition, and was likely ultimately driven by ocean de-acidification. [1] Sosdian et al. (2006) Geochemistry, Geophysics, Geosystems (G3) 7, Q11023, doi:10.1029/2005GC001233; [2

  15. Cenozoic vertical motions of the western continental margin of Peninsular India

    Science.gov (United States)

    Richards, Fred; Hoggard, Mark; White, Nicky

    2016-04-01

    Despite the cessation of rifting at ˜65 Ma and its remoteness from active convergence, the topography of Peninsular India is dominated by a dramatic, high-elevation escarpment along its western margin: the Western Ghats (˜1 - 1.5 km amsl). Inland of the escarpment, South Indian topography exhibits a long-wavelength (>1000 km), low-angle (˜0.1°) eastward tilt down to the Krishna-Godavari and Cauvery deltas on the eastern continental margin. Offshore, oceanic residual depth measurements show an identical long-wavelength asymmetry from highs of +1 km in the Arabian Sea to lows of -1.2 km in the Bay of Bengal. Strong evidence from margin stratigraphy, dated palaeosurfaces, thermochronology, cosmogenic nuclides and marine terraces combine to suggest that, following a period of relative quiescence from 50 Ma - 25 Ma, the present-day topography evolved in response to Neogene uplift and erosion along the western Indian margin. By jointly inverting 530 longitudinal river profiles for uplift rate and calibrating our inversions against these geological constraints, we successfully place this Cenozoic landscape evolution into a more complete spatio-temporal framework. The results demonstrate slow growth of the eastward tilt from 50 Ma - 25 Ma (≤0.02 mm a‑1), preceding a phase of increasingly rapid development - initiating in the south - from 25 Ma onwards (≤0.2 mm a‑1). The onset of rapid uplift pre-dates the initial intensification of the Indian monsoon by >15 Ma, suggesting that rock uplift and not climate change is primarily responsible for the modern-day relief of the peninsula. Previous studies have aimed to explain this topographic evolution by invoking flexural isostatic mechanisms involving denudation, sediment loading and/or underplating. However, seismological constraints show that South Indian topography deviates significantly from crustal isostatic expectations, while the 9.8‑2.2+3.8 km effective elastic thickness of the region generates ˜125 km

  16. Progress in faunal correlation of Late Cenozoic fluvial sequences 2000 4: the report of the IGCP 449 biostratigraphy subgroup

    Science.gov (United States)

    Schreve, D. C.; Keen, D. H.; Limondin-Lozouet, N.; Auguste, P.; Santisteban, Juan I.; Ubilla, M.; Matoshko, A.; Bridgland, D. R.; Westaway, R.

    2007-11-01

    Vertebrate and invertebrate faunal biostratigraphy is a well-tested method for establishing relative chronologies for fluviatile sequences that has proved useful in many parts of the world. The robust bones and teeth of large mammals are commonly found in fluviatile deposits, whereas small vertebrates can be readily recovered through systematic sieving of calcareous sediments, as can molluscs, the other major faunal group that has been used for biostratigraphical analysis of fluvial sequences. Because of their rapid and quantifiable rates of evolution, extinction, body mass change and dispersal during the Late Cenozoic, mammals are especially useful for ordering the fragmentary terrestrial sequence of interglacials and glacials, and proposing correlation with the global marine climatostratigraphic record. Other groups (e.g. reptiles and amphibians, ostracods) are as yet only in the initial stages of development as a dating tool, whereas some (e.g. fish, birds) still require substantial development in order to fully explore their utility. As part of IGCP 449, vertebrate and molluscan assemblages have made important contributions to datasets from a number of areas, notably northern France, central Germany, the Czech Republic and the Ukraine. Further south, mammalian assemblages have proved useful in separating discrete periods of climatic change in Iberia and Syria. At greater distances from the core area of fluvial biostratigraphical archives, significant contributions have come from South America (Uruguay River), South Africa (Vaal) and Australia (Riverine Plain and Lake Eyre drainage basin).

  17. Lagerstroemia L. from the middle Miocene Siwalik deposits, northern India: Implication for Cenozoic range shifts of the genus and the family Lythraceae

    Indian Academy of Sciences (India)

    Gaurav Srivastava; Rajan Gaur; R C Mehrotra

    2015-02-01

    Fossil leaves of Lagerstroemia (Lythraceae) are described from the Siwalik deposits (middle Miocene) of Kathgodam, Uttarakhand, India. The fossil records of the Lythraceae indicate its worldwide distribution in the Cenozoic. The family had its widest distribution during the Miocene but became less widespread during the Pliocene, followed by range expansion during the Quaternary. The present leaf fossil, along with the previous fossil records of Lagerstroemia, indicates that the genus followed the same pattern of expansion and retraction as the entire family Lythraceae suggesting that both the genus and the family adapted in similar ways. The fossil plant assemblage from the Lower Siwalik deposits indicates warm and humid climate with plenty of rainfall in the region during the depositional period.

  18. Cenozoic alkaline volcanic rocks with carbonatite affinity in the Bohemian Massif: Their sources and magma generation

    Czech Academy of Sciences Publication Activity Database

    Ulrych, Jaromír; Štěpánková-Svobodová, Jana

    2014-01-01

    Roč. 46, 1/2 (2014), s. 45-58. ISSN 0369-2086 R&D Projects: GA AV ČR(CZ) IAA300130902 Institutional support: RVO:67985831 Keywords : alkaline volcanic rocks * melilitic rocks * carbonatite s * magma generation * metasomatism * Cenozoic * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy

  19. Late Cenozoic History of the Genus Micromys (Mammalia, Rodentia) in Central Europe

    Czech Academy of Sciences Publication Activity Database

    Horáček, I.; Knitlová, M.; Wagner, Jan; Kordos, L.; Nadachowski, A.

    2013-01-01

    Roč. 8, č. 5 (2013), e62498. E-ISSN 1932-6203 R&D Projects: GA ČR GA205/09/0184 Institutional support: RVO:67985831 Keywords : Mammalia * Rodentia * Genus Micromys * Late Cenozoic Subject RIV: DB - Geology ; Mineralogy Impact factor: 3.534, year: 2013

  20. Greater India Basin hypothesis and a two-stage Cenozoic collision between India and Asia

    NARCIS (Netherlands)

    Hinsbergen, D.J.J. van; Lippert, P.C.; Dupont-Nivet, G.; McQuarrie, N.; Doubrovine, P.V.; Spakman, W.; Torsvik, T.H.

    2012-01-01

    Cenozoic convergence between the Indian and Asian plates produced the archetypical continental collision zone comprising the Himalaya mountain belt and the Tibetan Plateau. How and where India–Asia convergence was accommodated after collision at or before 52 Ma remains a long-standing controversy. S

  1. Greater India Basin hypothesis and a two-stage Cenozoic collision between India and Asia

    NARCIS (Netherlands)

    van Hinsbergen, D.J.J.; Lippert, P.; Dupont-Nivet, G.; McQuarrie, N.; Doubrovine, P.V.; Spakman, W.; Torsvik, T.H.

    2013-01-01

    Cenozoic convergence between the Indian and Asian plates produced the archetypical continental collision zone comprising the Himalaya mountain belt and the Tibetan Plateau. How and where India–Asia convergence was accommodated after collision at or before 52 Ma remains a long-standing controversy. S

  2. From mantle roots to surface eruptions: Cenozoic and Mesozoic continental basaltic magmatism

    Czech Academy of Sciences Publication Activity Database

    Kämpf, H.; Németh, K.; Puziewicz, J.; Mrlina, Jan; Geissler, W.H.

    2015-01-01

    Roč. 104, č. 8 (2015), s. 1909-1912. ISSN 1437-3254 Institutional support: RVO:67985530 Keywords : continental basaltic volcanism * BASALT 2013 conference * Cenozoic * Mesozoic Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.093, year: 2014

  3. The Amazonian Craton and its influence on past fluvial systems (Mesozoic-Cenozoic, Amazonia)

    NARCIS (Netherlands)

    C. Hoorn; M. Roddaz; R. Dino; E. Soares; C. Uba; D. Ochoa-Lozano; R. Mapes

    2010-01-01

    The Amazonian Craton is an old geological feature of Archaean/Proterozoic age that has determined the character of fluvial systems in Amazonia throughout most of its past. This situation radically changed during the Cenozoic, when uplift of the Andes reshaped the relief and drainage patterns of nort

  4. Climate directly influences Eocene mammal faunal dynamics in North America.

    Science.gov (United States)

    Woodburne, Michael O; Gunnell, Gregg F; Stucky, Richard K

    2009-08-11

    The modern effect of climate on plants and animals is well documented. Some have cautioned against assigning climate a direct role in Cenozoic land mammal faunal changes. We illustrate 3 episodes of significant mammalian reorganization in the Eocene of North America that are considered direct responses to dramatic climatic events. The first episode occurred during the Paleocene-Eocene Thermal Maximum (PETM), beginning the Eocene (55.8 Ma), and earliest Wasatchian North American Land Mammal Age (NALMA). The PETM documents a short (<170 k.y.) global temperature increase of approximately 5 degrees C and a substantial increase in first appearances of mammals traced to climate-induced immigration. A 4-m.y. period of climatic and evolutionary stasis then ensued. The second climate episode, the late early Eocene Climatic Optimum (EECO, 53-50 Ma), is marked by a temperature increase to the highest prolonged Cenozoic ocean temperature and a similarly distinctive continental interior mean annual temperature (MAT) of 23 degrees C. This MAT increase [and of mean annual precipitation (MAP) to 150 cm/y) promoted a major increase in floral diversity and habitat complexity under temporally unique, moist, paratropical conditions. Subsequent climatic deterioration in a third interval, from 50 to 47 Ma, resulted in major faunal diversity loss at both continental and local scales. In this Bridgerian Crash, relative abundance shifted from very diverse, evenly represented, communities to those dominated by the condylarth Hyopsodus. Rather than being "optimum," the EECO began the greatest episode of faunal turnover of the first 15 m.y. of the Cenozoic. PMID:19666605

  5. Late Cenozoic sedimentation in Pilot Knob Valley, California

    Science.gov (United States)

    Rittase, W. M.; Walker, J. D.; Kirby, E.; Andrew, J.; Wan, E.

    2012-12-01

    In Pilot Knob Valley (PKV), active inversion of a Pliocene-mid Pleistocene basin presents the opportunity to understand the spatial and temporal development of an enigmatic basin astride a major transform boundary in California. Here, a ~1000-m-thick package of exposed Late Cenozoic strata has been uplifted and tilted to the northeast. Based on new age and provenance data, we adopt the name Pilot Knob formation (PKfm) to describe much of these exposed rocks north of the Garlock fault (GF) and east of Christmas Canyon gate. Post-Miocene development of PKV is strongly influenced by the sinistral GF, the newly identified Marine Gate fault (MGF) and dextral Eastern California shear zone. The PKfm consists of three lithofacies members, from base to top: (1) rocks derived from Eagle Crags to the south; (2) Randsburg Wash lacustrine rocks; and (3) an upper member derived from the Slate Range. Tephrochronologic data from four PKfm ash samples brackets deposition of lacustrine Randsburg Wash Member rocks between 3.7-3.1 Ma and lacustrine rocks of the Slate Range Member between 1.2-0.6 Ma. A fifth tephrochronologic sample from lacustrine-distal alluvial sediments south of the GF near Christmas Canyon brackets deposition of a possible PKfm facies at ~3.1 Ma. A 3-stage tectonic model for northern PKV explains changing provenance patterns. Prior to ~3.1 Ma, the western PKV paleo-low lay north of the current GF adjacent to the southern Slate Range and connected to Searles Valley. The MGF cuts adjacent to the southern face of the Slate Range and southern Searles Valley with up to 7.5 km of sinistral oblique-normal slip between ~5-2.5 Ma. Eagle Crags fanglomerate deposition may continue after 3.7 Ma west of the Randsburg Wash-Searles Valley spillway, but these rocks have been eroded away. By ~3.7 Ma, northward progradation of Eagle Crags fanglomerate waned and lacustrine sediments were deposited north of the GF and east of the Randsburg Wash-Searles Valley spillway. At ~3.1 Ma

  6. Vertical-axis rotations determined from paleomagnetism of Mesozoic and Cenozoic strata of the Bolivian Andes

    Science.gov (United States)

    Richards, David R.; Butler, Robert F.; Sempere, Thierry

    2004-07-01

    Thermal demagnetization and principal component analysis allowed determination of characteristic remanent magnetization (ChRM) directions from 256 sites at 22 localities in Mesozoic and Cenozoic sedimentary strata of the Bolivian Altiplano and Eastern Cordillera. An inclination-only fold test of site-mean ChRM directions from Cenozoic units (principally the Santa Lucía Formation) indicates optimum unfolding at 97.1% unfolding, consistent with a primary origin for the ChRM. For Mesozoic strata, optimum unfolding occurred at 89.2%, perhaps indicating secondary remagnetization at some locations. For Cenozoic units, comparison of locality-mean directions with expected paleomagnetic directions indicates vertical-axis rotations from 33° counterclockwise to 24° clockwise. Euler pole analysis of along-strike variation in crustal shortening within the Subandean and Interandean zones indicates 18° clockwise rotation south of the axis of curvature of the Bolivian Andes and 6° counterclockwise rotation northwest of the axis during the past 10 m.y. Along-strike variation of shortening within the Eastern Cordillera indicates 8° clockwise rotation south of the axis and 8° counterclockwise rotation northwest of the axis from 35 to 10 Ma. These vertical-axis rotations produced by along-strike variations in crustal shortening during development of the Bolivian fold-thrust belt agree well with observed rotations determined from paleomagnetism of Cenozoic rocks in the Eastern Cordillera and in the Subandean and Interandean zones. However, local rotations are required to account for complex rotations in the Cochabamba Basin and within the Altiplano. The curvature of the Bolivian Andes has been progressively enhanced during Cenozoic fold-thrust belt deformation.

  7. Effect of volatiles erupted from Mesozoic and Cenozoic volcanic activities on paleo-environmental changes in China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Based on the determination of composition of volcanic volatiles and petrologic estimation of the total mass of volatiles erupted,we showed important advances in the study of the impact of Mesozoic and Cenozoic volcanic activities on paleo-environmental changes in China.The volcanic activities include western Liaoning and Zhangjiakou Mesozoic intermediate-acidic explosive eruptions,southern Tibet and Shanwang Cenozoic volcanism,and Mt.Changbai volcanic eruption around one thousand years ago.The paper predominantly discusses the earth's surface temperature changes,ozone depletion,acidic rain formation and mass mortalities of vertebrate induced by the Mesozoic and Cenozoic volcanism in China.

  8. Dramatic increase in late Cenozoic alpine erosion rates recorded by cave sediment in the southern Rocky Mountains

    Science.gov (United States)

    Refsnider, Kurt A.

    2010-09-01

    Apparent increases in sedimentation rates during the past 5 Ma have been inferred at sites around the globe to document increased terrestrial erosion rates, but direct erosion rate records spanning this period are sparse. Modern and paleo-erosion rates for a small alpine catchment (3108 m above sea level) in the Southern Rocky Mountains are measured using the cosmogenic radionuclides (CRNs) 10Be and 26Al in cave sediment, bedrock on the overlying landscape surface, and coarse bedload in a modern fluvial drainage. The unique setting of the Marble Mountain cave system allows the inherited erosion rates to be interpreted as basin-averaged erosion rates, resulting in the first CRN-based erosion rate record from the Rocky Mountains spanning 5 Myr. Pliocene erosion rates, derived from the oldest cave sample (4.9 ± 0.4 Ma), for the landscape above the cave are 4.9 ± 1.1 m Myr - 1 . Mid Pleistocene erosion rates are nearly an order of magnitude higher (33.1 ± 2.7 to 41.3 ± 3.9 m Myr - 1 ), and modern erosion rates are similar; due to the effects of snow shielding, these erosion rate estimates are likely higher than actual rates by 10-15%. The most likely explanation for this dramatic increase in erosion rates, which likely occurred shortly before 1.2 Ma, is an increase in the effectiveness of periglacial weathering processes at high elevations related to a cooler and wetter climate during the Pleistocene, providing support for the hypothesis that changes in late Cenozoic climate are responsible for increased continental erosion.

  9. A Climate Trend Analysis of Niger

    Science.gov (United States)

    Funk, Christopher C.; Rowland, Jim; Eilerts, Gary; Adoum, Alkhalil; White, Libby

    2012-01-01

    This brief report, drawing from a multi-year effort by the U.S. Agency for International Development (USAID) Famine Early Warning Systems Network (FEWS NET), identifies a substantial recovery of rainfall in Niger, accompanied by increases in air temperatures. These analyses are based on quality-controlled station observations. Conclusions: * Summer rains have increased during the past 20 years and have almost returned to 1960-89 levels. * Temperatures have increased by 0.6° Celsius since 1975, amplifying the effect of droughts. * Crop yields are very low and stagnant, and the population is growing very rapidly. * Niger has offset very rapid population growth with a large expansion of cultivated land. * If the expansion of farmland slows down, stagnant yields and population growth could lead to increased food insecurity.

  10. Cenozoic global sea level, sequences, and the New Jersey transect: Results from coastal plain and continental slope drilling

    Science.gov (United States)

    Miller, K.G.; Mountain, Gregory S.; Browning, J.V.; Kominz, M.; Sugarman, P.J.; Christie-Blick, N.; Katz, M.E.; Wright, J.D.

    1998-01-01

    The New Jersey Sea Level Transect was designed to evaluate the relationships among global sea level (eustatic) change, unconformity-bounded sequences, and variations in subsidence, sediment supply, and climate on a passive continental margin. By sampling and dating Cenozoic strata from coastal plain and continental slope locations, we show that sequence boundaries correlate (within ??0.5 myr) regionally (onshore-offshore) and interregionally (New Jersey-Alabama-Bahamas), implicating a global cause. Sequence boundaries correlate with ??18O increases for at least the past 42 myr, consistent with an ice volume (glacioeustatic) control, although a causal relationship is not required because of uncertainties in ages and correlations. Evidence for a causal connection is provided by preliminary Miocene data from slope Site 904 that directly link ??18O increases with sequence boundaries. We conclude that variation in the size of ice sheets has been a primary control on the formation of sequence boundaries since ~42 Ma. We speculate that prior to this, the growth and decay of small ice sheets caused small-amplitude sea level changes (sea level amplitudes are substantially lower than theirs. Lithofacies patterns within sequences follow repetitive, predictable patterns: (1) coastal plain sequences consist of basal transgressive sands overlain by regressive highstand silts and quartz sands; and (2) although slope lithofacies variations are subdued, reworked sediments constitute lowstand deposits, causing the strongest, most extensive seismic reflections. Despite a primary eustatic control on sequence boundaries, New Jersey sequences were also influenced by changes in tectonics, sediment supply, and climate. During the early to middle Eocene, low siliciclastic and high pelagic input associated with warm climates resulted in widespread carbonate deposition and thin sequences. Late middle Eocene and earliest Oligocene cooling events curtailed carbonate deposition in the coastal

  11. Meso-Cenozoic tectonics of the Central Kyrgyz Tien Shan (Central Asia), based on apatite fission track thermochronology.

    OpenAIRE

    Glorie, Stijn

    2008-01-01

    Apatite fission track thermochronology on the Kyrgyz Tien Shan basement revealed a polyphased thermal history of the study-area. We interpret the Mesozoic and Cenozoic cooling-events as periods of tectonic reactivation.

  12. Late Cenozoic sedimentary process and its response to the slip history of the central Altyn Tagh fault, NW China

    Institute of Scientific and Technical Information of China (English)

    陈正乐; 张岳桥; 陈宣华; 王小凤; A.S.Ramon; W.B.Zack

    2001-01-01

    The ENE-striking Altyn Tagh fault (ATF), extending along the northern edge of the Tibetan Plateau, is one of the major important strike-slip faults, and has been known as one of the key areas to debate the eastward extrusion and crustral shortening models of the Tibetan Plateau during and after India-Asia collision. This paper mainly presents new evidence of Late Cenozoic sedimentary process to reconstruct the slip history of the ATF during the Late Cenozoic. Field measurements and laboratory analyses of the sedimentary characteristics in the Late Cenozoic basins in the central Altyn Tagh fault suggest that Late Cenozoic sedimentary sequence should be divided into three units according to facies changes. The paleo-topography reconstruction shows that the sedimentation in these basins was tightly related with the fault, indicating that the ATF has experienced at least three stages of strike slipping in the Late Cenozoic. New geological data from the Late Cenozoic sedimentary basins and the formation of th

  13. Cenozoic Volcanism and Intraplate Subduction at the Northern Margin of the Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    邓万明

    1991-01-01

    Developed in the Mt.Kunlun orogenic belt at the northern margin of the Tibetan Plateau is an active Cenozoic volcanic zone which is more than 1000km in length and some ten to hundred kilometers in width.It extends east-westwards and is roughly parallet to the strike of Mt.Kunlun.The Cenozoic volcanic rocks are divided into the northern(N-)and southern(S-)subzones.Eruptions of volcanic lavas in the S-subzone are related to an initial rift zone within the north Qiangtang terrane,but the volcanic rocks in the N-subzone are relatively close to the contact zone between the Mt.Kunlun and the Tarim terrane.The space-time distribution,petrological and geochemical features can be explained by a model of southward intraplate subduction of the Tarim terrane.

  14. Characteristics and geological significance of olivine xenocrysts in Cenozoic volcanic rocks from western Qinling

    Institute of Scientific and Technical Information of China (English)

    SU Benxun; ZHANG Hongfu; XIAO Yan; ZHAO Xinmiao

    2006-01-01

    Cenozoic volcanic rocks from the Haoti, Dangchang County of the western Qinling Mountains, contain a few clearlyzoned olivines. These olivines are relatively big in grain sizes and usually have cracks or broken features. Their cores have similar compositions (Mg# = 90.4- 91.0) to those for the peridotitic xenoliths entrained in host volcanic rocks and their rims are close to the compositions of olivine phenocrysts (Mg# = 85.5 81.9). The CaO contents in these zoned olivines are lower than 0.1%. These features demonstrate that the clearly zoned olivines are xenocrysts and disaggregated from mantle peridotites. The zoned texture was the result of the interaction between the olivine and host magma. Available data show that the volcanic rocks would have been derived from the mantle source metasomatized by subducted hydrathermally-altered oceanic crust. The formation of these Cenozoic volcanic rocks was perhaps related to the rapid uplift of the Tibetan Plateau.

  15. Cenozoic evolution of Neotethys and implications for the causes of plate motions

    OpenAIRE

    McQuarrie, N.; J. M. Stock; Verdel, C.; B. P. Wernicke

    2003-01-01

    Africa-North America-Eurasia plate circuit rotations, combined with Red Sea rotations and new estimates of crustal shortening in Iran define the Cenozoic history of the Neotethyan ocean between Arabia and Eurasia. The new constraints indicate that Arabia-Eurasia convergence has been fairly constant at 2 to 3 cm/yr since 56 Ma with slowing of Africa-Eurasia motion to

  16. A universal driver of macroevolutionary change in the size of marine phytoplankton over the Cenozoic

    OpenAIRE

    Finkel, Z. V.; Sebbo, J.; Feist-Burkhardt, S.; Irwin, A. J.; Katz, M. E.; Schofield, O. M. E.; Young, J. R.; Falkowski, P G

    2007-01-01

    The size structure of phytoplankton assemblages strongly influences energy transfer through the food web and carbon cycling in the ocean. We determined the macroevolutionary trajectory in the median size of dinoflagellate cysts to compare with the macroevolutionary size change in other plankton groups. We found the median size of the dinoflagellate cysts generally decreases through the Cenozoic. Diatoms exhibit an extremely similar pattern in their median size over time, even though species d...

  17. Late Cenozoic deformation of the Gavrovo and Ionian zones in NW Peloponnesos (Western Greece)

    OpenAIRE

    S. Tsaila-Monopoli; O. Aximniotou; S. Sotiropoulos; E. Kamberis; C. Ioakim

    2000-01-01

    The structural deformation of Mesozoic-Tertiary sediments of the Ionian and Gavrovo zones in NW Peloponnesos is related to the propagation of a fold-thrust system during the Cenozoic. The sediments of the Gavrovo zone have been deformed by high angle reverse faulting generating an imbricate fan. Skolis mountain represents the Gavrovo thrust front. The detachment occurred in the underlying flysch of the Ionian zone. The Ionian zone has also been affected by shortening above a detachment horizo...

  18. Biogeographical consequences of Cenozoic tectonic events within East Asian margins: a case study of Hynobius biogeography.

    Directory of Open Access Journals (Sweden)

    Jun Li

    Full Text Available Few studies have explored the role of Cenozoic tectonic evolution in shaping patterns and processes of extant animal distributions within East Asian margins. We select Hynobius salamanders (Amphibia: Hynobiidae as a model to examine biogeographical consequences of Cenozoic tectonic events within East Asian margins. First, we use GenBank molecular data to reconstruct phylogenetic interrelationships of Hynobius by bayesian and maximum likelihood analyses. Second, we estimate the divergence time using the bayesian relaxed clock approach and infer dispersal/vicariance histories under the 'dispersal-extinction-cladogenesis' model. Finally, we test whether evolutionary history and biogeographical processes of Hynobius should coincide with the predictions of two major hypotheses (the 'vicariance'/'out of southwestern Japan' hypothesis. The resulting phylogeny confirmed Hynobius as a monophyletic group, which could be divided into nine major clades associated with six geographical areas. Our results show that: (1 the most recent common ancestor of Hynobius was distributed in southwestern Japan and Hokkaido Island, (2 a sister taxon relationship between Hynobius retardatus and all remaining species was the results of a vicariance event between Hokkaido Island and southwestern Japan in the Middle Eocene, (3 ancestral Hynobius in southwestern Japan dispersed into the Taiwan Island, central China, 'Korean Peninsula and northeastern China' as well as northeastern Honshu during the Late Eocene-Late Miocene. Our findings suggest that Cenozoic tectonic evolution plays an important role in shaping disjunctive distributions of extant Hynobius within East Asian margins.

  19. Cenozoic Volcanism in South China Sea and Its Vicinity and South China Sea Spreading

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The rock series, rock types and Sr-Nd isotopic dating of the Cenozoic volcanic rocks in the South China Sea are similar to those in its vicinity. On the basis of the spreading age of the South China Sea, the Cenozoic volcanic rocks are divided into three stages: the pre-spreading stage, the spreading stage and the post-spreading stage. The deep process characteristics of the asthenosphere and lithosphere may be inferred from the study on primary basaltic magma. The top layers of the asthenosphere both in the spreading stage and in the pre-spreading stage are closer to the earth surface than that in the post-spreading stage. From the pre-spreading stage to the spreading stage, the top layer of the asthenosphere decreased in depth, while the amount of interstitial partial melts increased. The evolution of the primary basaltic magma shows a progressive evolution sequence of the rifting volcanism and a faster lithospheric spreading velocity. From the spreading stage to the post-spreading stage, the top layer of the asthenosphere gradually increased in depth, but the amount of interstitial partial melts decreased. The evolution of primary basaltic magma shows a retrogressive evolution sequence of the rifting volcanism and a gradual decrease in the lithospheric spreading velocity. The depth recognized by the study on the Cenozoic volcanism demonstrates the deep environment for the formation and evolution of the South China Sea.

  20. Cenozoic Antarctic DiatomWare/BugCam: An aid for research and teaching

    Science.gov (United States)

    Wise, S.W.; Olney, M.; Covington, J.M.; Egerton, V.M.; Jiang, S.; Ramdeen, D.K.; Kulhanek S.; Schrader, H.; Sims, P.A.; Wood, A.S.; Davis, A.; Davenport, D.R.; Doepler, N.; Falcon, W.; Lopez, C.; Pressley, T.; Swedberg, O.L.; Harwood, D.M.

    2007-01-01

    Cenozoic Antarctic DiatomWare/BugCam© is an interactive, icon-driven digital-image database/software package that displays over 500 illustrated Cenozoic Antarctic diatom taxa along with original descriptions (including over 100 generic and 20 family-group descriptions). This digital catalog is designed primarily for use by micropaleontologists working in the field (at sea or on the Antarctic continent) where hard-copy literature resources are limited. This new package will also be useful for classroom/lab teaching as well as for any paleontologists making or refining taxonomic identifications at the microscope. The database (Cenozoic Antarctic DiatomWare) is displayed via a custom software program (BugCam) written in Visual Basic for use on PCs running Windows 95 or later operating systems. BugCam is a flexible image display program that utilizes an intuitive thumbnail “tree” structure for navigation through the database. The data are stored on Micrsosoft EXCEL spread sheets, hence no separate relational database program is necessary to run the package

  1. Cenozoic Mineralization in China, as a Key to Past Mineralization and a Clue to Future Prospecting

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Many Cenozoic metal deposits have been found during the past decade. Among them, the Fuwan Ag deposit in Guangdong is the largest Ag deposit in China. Besides, the largest Cu deposit of China in Yulong, Tibet, the largest Pb-Zn deposit of China in Jinding, Yunnan, and the largest Au deposit of China in Jinguashi,Taiwan, were also formed in the Cenozoic. Why so many important "present" deposits formed during such a short period of geological history is the key problem. The major reason is that different tectonic settings control different kinds of magmatic activity and mineralization at the same time. In southwestern China, porphyry-type Cu deposits such as Yulong were formed during the early stage of the Himalayan orogeny, sediment-hosted Pb-Zn deposits such as Jinding were formed within intermontane basins related to deep faults, and carbonatite-related deposits such as the Maoniuping REE deposit and alkalic magmatic rock-related deposits such as the Beiya Au deposit originated from the mantle source. In southeastern China, the Fuwan Ag deposit was related to continental rifting which was triggered by the mantle plume. In Taiwan, the Jinguashi Au deposit was formed during the subduction process of an oceanic plate beneath a continental plate. Besides, the features such as the diversification, inheritance, large size, deep source of metals and fluids of the Cenozoic (Present or Recent ) mineralization can be used as a key to the search for past deposits.

  2. Metallogenic systems related to Mesozoic and Cenozoic granitoids in South China

    Institute of Scientific and Technical Information of China (English)

    HUA; Renmin; (华仁民); CHEN; Peirong; (陈培荣); ZHANG; Wenlan; (张文兰); LIU; Xiaodong; (刘晓东); LU; Jianjun; (陆建军); LIN; Jinfu; (林锦富); YAO; Junming; (姚军明); QI; Huawen; (戚华文); ZHANG; Zhanshi; (张展适); GU; Shengyan; (顾晟彦)

    2003-01-01

    Large scale mineralizations of nonferrous, precious, and rare metals took place in South China in Mesozoic and Cenozoic Eras, which were mostly closely related with granitic magmatisms of different sources and features. Four metallogenic systems related to Mesozoic and Cenozoic granitoids are put forward in this paper. They are: (i) the porphyry-epithermal copper-gold system related to calc-alkaline volcanic-intrusive magmatism, (ii) rare metal (mainly W, Sn, Ta, Nb, etc) metallogenic system related with continental crust re-melting type granitoids, (iii) copper and polymetallic metallogenic system related with intra-plate high potassium calc-alkaline and shoshonitic magmatism, and (iv) Au-Cu and REE metallogenic system related to A-type granites. The main characteristics of these systems are briefly discussed. These Mesozoic and Cenozoic granitoids of different sources were the products of different periods of lithosphere evolution in that area under different tectonic-dynamic environments. Fundamentally speaking, however, the granitoids and related metallogeneses are the results of mantle-crust interactions under a tensile tectonic environment in South China.

  3. Trend patterns in global sea surface temperature

    DEFF Research Database (Denmark)

    Barbosa, S.M.; Andersen, Ole Baltazar

    2009-01-01

    Isolating long-term trend in sea surface temperature (SST) from El Nino southern oscillation (ENSO) variability is fundamental for climate studies. In the present study, trend-empirical orthogonal function (EOF) analysis, a robust space-time method for extracting trend patterns, is applied to...... isolate low-frequency variability from time series of SST anomalies for the 1982-2006 period. The first derived trend pattern reflects a systematic decrease in SST during the 25-year period in the equatorial Pacific and an increase in most of the global ocean. The second trend pattern reflects mainly ENSO...... variability in the Pacific Ocean. The examination of the contribution of these low-frequency modes to the globally averaged SST fluctuations indicates that they are able to account for most (>90%) of the variability observed in global mean SST. Trend-EOFs perform better than conventional EOFs when the...

  4. The relationship between the growth process of the ferromanganese crusts in the Pacific seamount and Cenozoic ocean evolvement

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Base on the Os isotope stratigraphy together with the empirical growth rate models using Co concentrations, the growth ages of the ferromanganese crusts MHD79 and MP3D10 distributed in the seamount of Pacific are confirmed. Through the contrast and research on the previous achievements including ODP Leg 144 and the crusts CD29-2, N5E-06 and N1-15 of the seamount of the Central Pacific, the uniform five growth and growth hiatus periods of them are found, and closely related to the Cenozoic ocean evolvement process. In the Paleocene Carbon Isotope Maximum (PCIM), the rise of the global ocean productivity promoted the growth of the seamount crust; the first growth hiatus (I) of the ferromanganese crust finished. In the Paleocene-Eocene Thermal Maximum (PETM), though the vertical exchange of seawater was weakened, the strong terrestrial chemical weathering led to the input of a great amount of the terrigenous nutrients, which made the bioproductivity rise, so there were no crust hiatuses. During 52-50 Ma, the Early Eocene Optimum Climate (EECO), the two poles were warm, the latitudinal temperature gradient was small, the wind-driven sea circulation and upwelling activity were weak, the terrestrial weathering was also weakened, the open ocean bioproductivity decreased, and the ferromanganese crust had growth hiatus again (II). From early Middle Eocene-Late Eocene, Oligocene, it was a long-term gradually cooling process, the strengthening of the sea circulation and upwelling led to a rise of bioproductivity, and increase of the content of the hydrogenous element Fe, Mn and Co and the biogenous element Cu, Zn, so that was the most favorable stage for the growth of ferromanganese crust (growth periods III and IV) in the studied area. The hiatus III corresponded with the Eocene-Oligocene boundary, is inferred to relate with the global climate transformation, celestial body impact event in the Eocene-Oligocene transition. From the early to the middle Miocene, a large

  5. The relationship between the growth process of the ferromanganese crusts in the Pacific seamount and Cenozoic ocean evolvement

    Institute of Scientific and Technical Information of China (English)

    DING Xuan; GAO LianFeng; FANG NianQiao; QU Wendun; LIU Jian; LI JiangShan

    2009-01-01

    Base on the Os Isotope stratigraphy together with the empirical growth rate models using Co concentrations, the growth ages of the ferromanganese crusts MHD79 and MP3D10 distributed in the seamount of Pacific are confirmed. Through the contrast and research on the previous achievements including ODP Leg 144 and the crusts CD29-2, N5E-06 and N1-15 of the seamount of the Central Pacific,the uniform five growth and growth hiatus periods of them are found, and closely related to the Cenozoic ocean evolvement process. In the Paleocene Carbon Isotope Maximum (PClM), the rise of the global ocean productivity promoted the growth of the seamount crust; the first growth hiatus (Ⅰ) of the ferromanganese crust finished. In the Paleocene-Eocene Thermal Maximum (PETM), though the vertical exchange of seawater was weakened, the strong terrestrial chemical weathering led to the input of a great amount of the terrigenous nutrients, which made the bioproductivity rise, so there were no crust hiatuses. During 52-50 Me, the Early Eocene Optimum Climate (EECO), the two poles were warm, the latitudinal temperature gradient was small, the wind-driven sea circulation and upwelling activity were weak, the terrestrial weathering was also weakened, the open ocean bioproductivity decreased, and the ferromanganese crust had growth hiatus again (Ⅱ). From early Middle Eocene-Late Eocene, Oligocene,it was a long-term gradually cooling process, the strengthening of the sea circulation and upweUing led to a rise of bioproductivity, and increase of the content of the hydrogenous element Fe, Mn and Co and the biogenous element Cu, Zn, so that was the most favorable stage for the growth of ferromanganese crust (growth periods Ⅲ and IV) in the studied area. The hiatus Ⅲ corresponded with the Eocene-Oligocene boundary, is inferred to relate with the global climate transformation, celestial body impact event in the Eocene-Oligocene transition. From the early to the middle Miocene, a large

  6. Tectonic and Climatic Controls on Landscape Development of Puerto Rico

    Science.gov (United States)

    Rogers, R. D.; Salas, M.; Colon, A.

    2007-12-01

    The northeastern Caribbean island of Puerto Rico is an exhumed Cenozoic island arc situated between the inactive Muertos trench to the south and the highly oblique Puerto Rican Trench to the north that forms the left- lateral strike-slip plate margin with North America. The rectangular island's long axis of 175 km parallels the east trending strike of the trenches with a near constant width of between 50 and 60 km. Puerto Rico receives the NE trade winds and has a tropical monsoonal climate. Puerto Rico has a distinct midline asymmetry with north draining watershed about twice the length and five times as large as south draining watershed. This midline asymmetry is more pronounced along the islands eastern third than the central or western thirds. River outlet spacing, mountain front sinuosity, and comparative hypsometry display similar east to west variability consistent with greater denudation in the eastern parts of the island. The southwestern fifth of the island is underlain by serpentinized ocean crust that forms the large diapiric Monte del Estado uplift. Active diapirism is indicated by highly asymmetric watersheds of the surrounding rivers and tributaries. Stream length gradient index calculated from 1:20,000 scale map data and compared to fault locations show little correlation suggesting that active faults does not significantly control Puerto Rico's landscape. Quantified morphologic data from the eastern two-thirds of Puerto Rico are consistent with a landscape developed in response to the precipitation derived from NE trade winds while serpentinite diapirism dominates the western third of the island. Individual active faults of Puerto Rico do not control the landscape development.

  7. Plate tectonics, seaways and climate in the historical biogeography of mammals

    Directory of Open Access Journals (Sweden)

    C Barry Cox

    2000-08-01

    Full Text Available The marsupial and placental mammals originated at a time when the pattern of geographical barriers (oceans, shallow seas and mountains was very different from that of today, and climates were warmer. The sequence of changes in these barriers, and their effects on the dispersal of the mammal families and on the faunas of mammals in the different continents, are reviewed. The mammal fauna of South America changed greatly in the Pliocene/Pleistocene, when the newly-complete Panama Isthmus allowed the North American fauna to enter the continent and replace most of the former South American mammal families. Marsupial, but not placental, mammals reached Australia via Antarctica before Australia became isolated, while rats and bats are the only placentals that dispersed naturally from Asia to Australia in the late Cenozoic. Little is known of the early history of the mammal fauna of India. A few mammal families reached Madagascar from Africa in the early Cenozoic over a chain of islands. Africa was isolated for much of the early Cenozoic, though some groups did succeed in entering from Europe. Before the climate cooled in the mid-Cenozoic, the mammal faunas of the Northern Hemisphere were much richer than those of today.

  8. Climate plan 2004; Plan climat 2004

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The Climate Plan is an action plan drawn up by the French Government to respond to the climate change challenge, first by 2010 (complying with the Kyoto Protocol target), and, secondly, beyond this date. Projections for France show that national emissions could be 10% higher than the Kyoto target in 2010 if no measures are taken. This is particularly due to increasing emissions in the sectors affecting daily life (residential-tertiary sectors, transport, etc.). For this reason, the Climate Plan contains measures affecting all sectors of the economy and the daily life of all French citizens with a view to economizing the equivalent of 54 million tonnes of CO{sub 2} each year by the year 2010, which will help to reverse the trend significantly. Beyond 2010, the Climate Plan sets out a strategy for technological research which will enable France to meet a target of reducing greenhouse gas emissions four or fivefold by 2050. (author)

  9. Cenozoic tectono-geomorphological growth of the SW Chinese Tian Shan: insight from AFT and detrital zircon U-Pb data

    OpenAIRE

    Jia, Yingying; Fu, Bihong; Jolivet, Marc; Zheng, Shuo

    2015-01-01

    As a unique example of the intracontinental mountain building, the Cenozoic deformation of the Tian Shan has been widely studied. The onset of Cenozoic exhumation of the SW Chinese Tian Shan was constrained at the Oligocene-Miocene boundary. However, the Cenozoic tectono-geomorphological growth process of the SW Chinese Tian Shan and adjacent piedmont basins remains a challenge. In this study, we carried out the geological mapping of satellite images and field investigations together with the...

  10. Constraining the vertical surface motions of the Hampshire Basin, south England During the Cenozoic

    Science.gov (United States)

    Smith, Philip; England, Richard; Zalasiewicz, Jan

    2016-04-01

    The potential effect of rising sea level on the UK has received considerable attention in recent years. However, the ongoing long-term changes in surface topography of the UK driven by regional tectonics and the mechanisms responsible are not fully understood. It is thought that glacial loading/unloading is the primary influence. However, this is inconsistent with present-day vertical surface motions recorded from Continuous Global Positioning Stations (CGPS) across the UK. The lateral variations in the present day motions are too complex to be explained by glacial isostatic rebound. We are investigating the hypothesis that the vertical motions of SE England also reflect the long term tectonic history by backstripping the Cenozoic geological record. So far the Paleogene stratigraphic record of the Hampshire basin in southern England has been investigated and using a series of deep boreholes that reach the chalk basement, a 2-D backstripping method has been applied. Subsidence analysis of cliff sections and boreholes reveal the Hampshire Basin was tectonically subsiding at a steady rate from 56.5Ma and any major periods of uplift and denudation to the present day state must have occurred from the mid Oligocene onwards. At this time the northern and western regions of the UK were believed to be uplifting as evidenced by heavy mineral transport directionns and sediment drainage patterns. A rapid increase in tectonic subsidence from 42Ma recorded by the three Isle of Wight sections in close proximity to an existing Variscan fault, thought to reactivate as a thrust during the Cenozoic, suggests a compressional stress regime in this region. The stress pattern observed from the tectonic subsidence data and evidence from drainage patterns supports a model in which the UK was uplifting in the north and west while the south east was subsiding. As this pattern is similar to the present day vertical surface motions and pre-dates glaciation, we propose glacial unloading as a

  11. Variations in Cenozoic seawater uranium reconstructed from well preserved aragonitic fossil corals

    Science.gov (United States)

    Gothmann, A. O.; Higgins, J. A.; Bender, M. L.; Stolarski, J.; Adkins, J. F.; McKeon, R. E.; Farley, K. A.; Wang, X.; Planavsky, N.

    2015-12-01

    U/Ca ratios were measured in a subset (n ≈ 30) of well preserved scleractinian fossil corals previously described by Gothmann et al. (2015) in order to investigate Cenozoic changes in seawater [U]. He/U dating studies and measurements of 234U/238U and δ238/235U provide constraints on fossil coral U preservation. He/U ages also demonstrate the ability of well preserved coral aragonite to retain most of its radiogenic He over million year timescales. We find that fossil coral U/Ca has increased by a factor of ~4 between the Early Cenozoic and today. This number is calculated from the change in seawater [Ca2+] implied by brine inclusions and other proxies, and the assumption that the U/Ca in shallow water corals equals the seawater ratio. The change cannot be attributed to a dependence of coral U uptake on seawater pH or [CO32-] (e.g., Inoue et al., 2011), which would lead to a decrease in U/Ca going forward in time. Instead, we suggest that seawater [U] has increased since the Early Cenozoic. Possible explanations for the inferred change include: (1) a small decrease in uranium uptake in suboxic and anoxic sediments over the Cenozoic, (2) a decrease in the rate of low-temperature hydrothermal alteration, and associated U uptake, over the Cenozoic, and (3) a decrease in U removal from seawater resulting from an increase in UO2-CO3 complexation, as originally suggested by Broecker (1971). References: Broecker, W. S. (1971) A Kinetic Model for the Chemical Composition of Sea Water. Quaternary Research, 1, 188-207. Gothmann, A.M., Stolarski, J., Adkins, J.F., Dennis, K.J., Schrag, D.P., Schoene, B., Bender, M.L. (2015) Fossil corals as an archive of secular variations in seawater chemistry. Geochimica et Cosmochimica Acta, 160, 188-208. Inoue, M., Suwa, R., Suzuki, A., Sakai, K., and Kawahata, H., (2011) Effects of seawater pH on growth and skeletal U/Ca ratios of Acropora digitifera coral polyps. Geophysical Research Letters 38, 12801-12804.

  12. Late Cenozoic geology and lacustrine history of Searles Valley, Inyo and San Bernardino Counties, California

    Science.gov (United States)

    Nathenson, M.; Smith, G. I.; Robinson, J. E.; Stauffer, P. H.; Zigler, J. L.

    2010-12-01

    (beaches or tufa benches) are common, but their deposits tend to be thin. Combining the subsurface evidence of lake history with the outcrop record allows the history of lake fluctuations to be reconstructed for the period between about 150 ka and the present. Translating this record of lake fluctuations into paleohydrologic and paleoclimatic histories is complicated by uncertainties as to which of the several components of climate affected runoff volumes and lake-surface evaporation. A simplified model, however, suggests that the flow of the Owens River stayed between 2.5 and 4.5 times its present flow volume for most of the past 150 ky. Its flow exceeded this range only about 14 percent of the time, and it fell below this range only 4 percent of the time—which includes the present. In fact, the past 10 ky is clearly the driest period during the past 150 ky in the Owens River drainage. Smith, G.I., 2009, Late Cenozoic geology and lacustrine history of Searles Valley, Inyo and San Bernardino Counties, California: U.S. Geological Survey Professional Paper 1727, 115 p., 4 plates.

  13. Climatization

    DEFF Research Database (Denmark)

    Grant, Stephen; Tamason, Charlotte Crim; Jensen, Peter Kjær Mackie

    2015-01-01

    In recent years, there has been a developing trend of labelling some disasters as ‘climatechange disasters’. In doing so, a discursive phenomenon can emerge that the authors havecoined ‘climatization’ which is specified as framing a disastrous event or degraded environmentalcondition as caused...... by climate change, in order to reach an intended goal or to distractthe discussion from the real problem which might have a different root course than caused bythe climate change effects. The implications of climatization are currently unclear – particularly to what extent climatizinga disaster might...

  14. Googling trends in conservation biology.

    Science.gov (United States)

    Proulx, Raphaël; Massicotte, Philippe; Pépino, Marc

    2014-02-01

    Web-crawling approaches, that is, automated programs data mining the internet to obtain information about a particular process, have recently been proposed for monitoring early signs of ecosystem degradation or for establishing crop calendars. However, lack of a clear conceptual and methodological framework has prevented the development of such approaches within the field of conservation biology. Our objective was to illustrate how Google Trends, a freely accessible web-crawling engine, can be used to track changes in timing of biological processes, spatial distribution of invasive species, and level of public awareness about key conservation issues. Google Trends returns the number of internet searches that were made for a keyword in a given region of the world over a defined period. Using data retrieved online for 13 countries, we exemplify how Google Trends can be used to study the timing of biological processes, such as the seasonal recurrence of pollen release or mosquito outbreaks across a latitudinal gradient. We mapped the spatial extent of results from Google Trends for 5 invasive species in the United States and found geographic patterns in invasions that are consistent with their coarse-grained distribution at state levels. From 2004 through 2012, Google Trends showed that the level of public interest and awareness about conservation issues related to ecosystem services, biodiversity, and climate change increased, decreased, and followed both trends, respectively. Finally, to further the development of research approaches at the interface of conservation biology, collective knowledge, and environmental management, we developed an algorithm that allows the rapid retrieval of Google Trends data. PMID:24033767

  15. Communities under climate change

    DEFF Research Database (Denmark)

    Nogues, David Bravo; Rahbek, Carsten

    2011-01-01

    The distribution of species on Earth and the interactions among them are tightly linked to historical and contemporary climate, so that global climate change will transform the world in which we live. Biological models can now credibly link recent decadal trends in field data to climate change......, but predicting future impacts on biological communities is a major challenge. Attempts to move beyond general macroecological predictions of climate change impact on one hand, and observations from specific, local-scale cases, small-scale experiments, or studies of a few species on the other, raise a plethora...... of unanswered questions. On page 1124 of this issue, Harley (1) reports results that cast new light on how biodiversity, across different trophic levels, responds to climate change....

  16. Monitoring Phenological Trends From Satellite Imagery

    Science.gov (United States)

    Reed, B.; Brown, J.; Whalen, A.

    2004-12-01

    While there is convincing evidence that global climate change is taking place, there is still considerable controversy over the magnitude and consequences of any changes. One of the primary manifestations of climate change is the effect on patterns of vegetation growth; the timing of the growing season, the vigor of vegetation, and vegetation composition. The satellite data record provides an objective view of vegetation activity by measuring surface reflectance values at regular time intervals. Time-series analyses of satellite data can provide information on emerging trends of vegetation dynamics that may be related to global change. The objective of this project is to conduct a trend analysis of vegetation dynamics in the conterminous United States, as measured by satellite data, to assess regions of changing vegetation activity, and to evaluate the regions to determine the driving forces of these changes. To assess vegetation dynamics we analyze phenological metrics (e.g., time of start of season , end of season, duration of season, and seasonally integrated greenness) derived from satellite data and evaluate trends in these metrics by studying the climate record, agricultural statistics, and land cover data bases to assess the driving forces of the trends. The types of trends that we identify include trends toward earlier/later start and end of season, longer/shorter growing seasons, and greater/lesser vegetation production. Early results indicate geographically specific drivers across various ecoregions of the US.

  17. Deterministic versus stochastic trends: Detection and challenges

    Science.gov (United States)

    Fatichi, S.; Barbosa, S. M.; Caporali, E.; Silva, M. E.

    2009-09-01

    The detection of a trend in a time series and the evaluation of its magnitude and statistical significance is an important task in geophysical research. This importance is amplified in climate change contexts, since trends are often used to characterize long-term climate variability and to quantify the magnitude and the statistical significance of changes in climate time series, both at global and local scales. Recent studies have demonstrated that the stochastic behavior of a time series can change the statistical significance of a trend, especially if the time series exhibits long-range dependence. The present study examines the trends in time series of daily average temperature recorded in 26 stations in the Tuscany region (Italy). In this study a new framework for trend detection is proposed. First two parametric statistical tests, the Phillips-Perron test and the Kwiatkowski-Phillips-Schmidt-Shin test, are applied in order to test for trend stationary and difference stationary behavior in the temperature time series. Then long-range dependence is assessed using different approaches, including wavelet analysis, heuristic methods and by fitting fractionally integrated autoregressive moving average models. The trend detection results are further compared with the results obtained using nonparametric trend detection methods: Mann-Kendall, Cox-Stuart and Spearman's ρ tests. This study confirms an increase in uncertainty when pronounced stochastic behaviors are present in the data. Nevertheless, for approximately one third of the analyzed records, the stochastic behavior itself cannot explain the long-term features of the time series, and a deterministic positive trend is the most likely explanation.

  18. Online Marketing Trends

    OpenAIRE

    Horecká, Ivana

    2015-01-01

    This thesis deals with online marketing trends. Its main goal is to define the latest online marketing trends, create a website with the free online marketing trends, and analyse their effectiveness. The theoretical part brings a thorough description of the latest online marketing trends. Moreover, it provides an insight into the latest trends in the website development. The chosen online marketing trends defined in the theoretical part are subsequently applied on a newly created website. All...

  19. Paleogeographic and tectonic controls on the evolution of Cenozoic basins in the Altiplano and Western Cordillera of southern Peru

    Science.gov (United States)

    Carlotto, Víctor

    2013-03-01

    Integrated studies of stratigraphy, sedimentology, paleogeography and tectonic controls on Cenozoic basins provide the basis for a series of time-slice reconstructions of basin evolution in the Andes of southern Peru. The Altiplano and adjacent margin of the Western Cordillera are characterized by several Paleocene-Miocene synorogenic continental basins with thicknesses locally exceeding 10 km. The evolution of these basins has been controlled by NW-trending tectonic features that mark the Altiplano-Western Cordillera and Altiplano-Eastern Cordillera boundaries and the Condoroma structural high. Sedimentary deposits of Paleocene age preserved in the Altiplano are the result of nonmarine sedimentation in a distal foreland basin. During the early Eocene, predominantly dextral strike-slip movements in the Altiplano between the Cusco-Lagunillas and Urcos-Ayaviri fault systems created the transpressional Kayra basin. The Soncco and Anta basins (middle Eocene-early Oligocene) are related to NE shortening (43-30 Ma) and represent proximal, wedge-top and foredeep basin environments preserved on the Altiplano. At ~ 29-28 Ma, a change to predominantly E-W shortening produced sinistral strike-slip motion along NW-striking faults, resulting in intermontane, transpressional basins. In the Altiplano, the Tinajani and Punacancha (29-5 Ma), and Paruro (12-6 Ma) basins were controlled by the Cusco-Lagunillas and the Urcos-Ayaviri fault systems. The Maure, Tincopalca-Huacochullo and Condoroma basins (22-5 Ma) of the Western Cordillera developed between the Condoroma high and the Cusco-Lagunillas fault system. Oligocene-Miocene sedimentation commonly evolved from proximal (alluvial) facies along the borders to distal (lacustrine) facies. These basins were linked to sinistral strike-slip faults that evolved into reverse-sinistral structures. Plate kinematics may play a role in Andean basin evolution, with deformation influenced by major preexisting faults that dictated paleogeographic

  20. Assessment of trends in point rainfall using Continuous Wavelet Transforms

    Science.gov (United States)

    Rashid, Md. Mamunur; Beecham, Simon; Chowdhury, Rezaul Kabir

    2015-08-01

    The existence of trends in hydro-climatic variables such as rainfall is an indication of potential climate variability and climate change and the identification of such trends in rainfall is essential for the planning and design of sustainable water resources. This study focuses on identifying existing trends in annual, seasonal and monthly rainfall at thirteen stations in the Onkaparinga catchment in South Australia during the period 1960-2010. A relatively new trend detection approach, which combines a Continuous Wavelet Transform (CWT) with the Mann Kendall (MK) test, was applied in this study. The original rainfall time series was decomposed to different periodic components using a CWT and then the MK test was applied to detect the trends. One station showed a statistically significant (at the 5% level) negative trend for annual rainfall. Winter rainfall exhibited significant positive trends at four stations. In the case of monthly rainfall, significant positive trends were observed in June (at seven stations), November (at one station) and December (at one station). The study showed that the periodic components might have significant trends even when there are no significant trends in the original data. The periodic component that dominates the trend in the original data varies from season to season. A sequential Mann-Kendall analysis was found useful for identifying the trend turning points. Most of the trends, whether positive or negative, started during the mid-1970s to mid-1980s. The technique developed in this study may also be applied for trend detection of other hydro-climatic variables in other catchments, particularly where temporal and spatial variabilities are high.

  1. Trends in timing and magnitude of flow in the Upper Indus Basin

    OpenAIRE

    M. Sharif; Archer, D.R.; Fowler, H J; N. Forsythe

    2012-01-01

    River flow is a reflection of the input of moisture and its transformation in storage and transmission over the catchment. In the Upper Indus Basin (UIB), since high altitude climate measurement and observations of glacier mass balance are weak or absent, analysis of trends in magnitude and timing in river flow provides a window on trends and fluctuations in climate and glacier outflow. Trend analysis is carried out using a Mann-Kendall nonparametric trend test on records extending from ...

  2. Trends in timing and magnitude of flow in the Upper Indus Basin

    OpenAIRE

    M. Sharif; Archer, D.R.; Fowler, H J; N. Forsythe

    2013-01-01

    River flow is a reflection of the input of moisture and its transformation in storage and transmission over the catchment. In the Upper Indus Basin (UIB), since high-altitude climate measurement and observations of glacier mass balance are weak or absent, analysis of trends in magnitude and timing in river flow provides a window on trends and fluctuations in climate and glacier outflow. Trend analysis is carried out using a Mann–Kendall nonparametric trend test on records ex...

  3. Teaching patterns and trends

    OpenAIRE

    Knoops, Femke; Erbil, Fethiye; Ertürk, Mustafa

    2012-01-01

    1. Outline 2. Definition 3. Why is it important (or not) to teach about patterns and trends? What are the strengths and weaknesses of teaching patterns and trends? 4. How were patterns and trends offered in the original assignments? 5. What did the student teacher change in practice? How did it go? 6. Suggestions for improving patterns and trends

  4. Discovery of Enclaves from Cenozoic Pulu Volcanic Rocks in West Kunlun Mountains and Its Geological Implications

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this paper, we present the occurrence and mineral components of the enclaves firstly discovered in the Cenozoic Pulu volcanic rocks in west Kunlun Mountains, and propose that the enclave is accumulated by fractional crystallization within high-level magma chamber. In addition, the chemical compositions of its primary magma are calculated. The calculated compositions are similar to those of the Kangxiwa volcanic rocks that belong to the same volcanic belt in the Pulu volcanic region, suggesting their origin from the same source region. However, the temperatures and oxygen fugacity of magmas at high-level magma chamber decreased along with fractional crystallization.

  5. Greater India Basin Hypothesis and A Two-Stage Cenozoic Collision Between India and Asia

    OpenAIRE

    D. J. J. van Hinsbergen; Lippert, P.C.; Dupont-Nivet, G.; McQuarrie, N.; Doubrovine, P. V.; Spakman, W.; T. H. Torsvik

    2013-01-01

    Cenozoic convergence between the Indian and Asian plates produced the archetypical continental collision zone comprising the Himalaya mountain belt and the Tibetan Plateau. How and where India–Asia convergence was accommodated after collision at or before 52 Ma remains a long-standing controversy. Since 52 Ma, the two plates have converged up to 3,600 ± 35 km, yet the upper crustal shortening documented from the geological record of Asia and the Himalaya is up to approximately 2,350-km less. ...

  6. Review of the upper Cenozoic stratigraphy overlying the Columbia River Basalt Group in western Idaho

    International Nuclear Information System (INIS)

    This report is a synthesis of information currently available on the rocks that stratigraphically overlie the Columbia River Basalt Group in Idaho. The primary objective is to furnish a brief but comprehensive review of the literature available on upper Cenozoic rocks in western Idaho and to discuss their general stratigraphic relationships. This study also reviews the derivation of the present stratigraphy and notes weaknesses in our present understanding of the geology and the stratigraphy. This report was prepared in support of a study to evaluate the feasibility of nuclear waste storage in the Columbia River Basalt Group of the Pasco Basin, Washington

  7. Long-term Stability of Global Erosion Rates and Weathering Fluxes during late Cenozoic Cooling

    OpenAIRE

    Willenbring, J.K.; Friedhelm von Blanckenburg

    2009-01-01

    Over geologic timescales, removal of atmospheric CO2 by weathering of silicate rocks balances CO2 input from the Earth´s interior. The coincidence of global cooling and the rise of mountain belts during the late Cenozoic has led geologists to suggest feedbacks between these two events. A centerpiece of t5his hypothesis was partially founded on observations of a young (0-5 My) 4-fold increase in global sedimentation rates, which seemed like a clear proxy for increased denudation and uplift of ...

  8. MESOZOIC-CENOZOIC INVERSION OFTHE TURPAN-HAMI BASIN, NORTHWEST CHINA

    Institute of Scientific and Technical Information of China (English)

    CaoDaiyong; QianGuangmo; ZhangPengfei; MeiMeitang; JinKuili; TangYuegang

    1996-01-01

    The Turpan-Hami basin, rich in coal and petroleum, is a superimposedbasin of three types basins in different tectonic environments. This coal, oil and gasbasin has undergone a complex tectonic-sedimentary evolution, in which two important stages were the negative inversion from a foredeep to a extensional basin duringEarly Mesozoic and the positive inversion to a thrust foreland basin in Late MesozoicEarly Cenozoic. The early normal faults residues are recognized with the addition oftectonic-sedimentary analysis to confirm the basin extension during Jurassic time andits tectonic inversion subsequently.

  9. Wrench-Slip Reversals and Structural Inversions: Cenozoic Slide-Rule Tectonics in Sundaland

    OpenAIRE

    Tjia, H.D.

    2014-01-01

    DOI: 10.17014/ijog.v1i1.174Most of continental Southeast Asia, that is, Sundaland and Indosinia, achieved a relative tectonic stability by the beginning of the Cenozoic. Since then a strong tectonic activity in Sundaland has been restricted to existing regional fault zones and to regional slow, vertical crustal movements elsewhere that produced small to very large sedimentary basins. On the other hand, regional deformation of Indosinia as a consequence of ductile shearing has continued into t...

  10. New Eocene damselflies and first Cenozoic damsel-dragonfly of the isophlebiopteran lineage (Insecta: Odonata).

    Science.gov (United States)

    Garrouste, Romain; Nel, André

    2015-01-01

    The study of a new specimen of Petrolestes hendersoni from the Eocene Green Formation allows a more precise description of the enigmatic damselfly and the diagnosis of the Petrolestin