WorldWideScience

Sample records for proxy climate indicators

  1. Development and refinement of proxy-climate indicators from peats

    NARCIS (Netherlands)

    Chambers, F.M.; Booth, R.K.; De Vleeschouer, F.; Lamentowicz, M.; Le Roux, G.; Mauquoy, D.; Nichols, J.E.; van Geel, B.

    2012-01-01

    Peat, especially from acidic mires (bogs), is a natural archive of past environmental change. Reconstructions of past climate from bogs commenced in the 19th Century through examination of visible peat stratigraphy, and later formed the basis for a postglacial climatic scheme widely used in

  2. A 25 ky BP record of Himalayan aridity using muscovite and clays as proxy climate indicators

    Digital Repository Service at National Institute of Oceanography (India)

    Gujar, A.R.; Chauhan, O.S.

    Based upon the temporal variations in the grain size parameters, characteristic clay minerals, their ratios and detrital muscovite content in a isotopically dated turbidity free core from hemipelagic environment. (2713 m water depth), the climatic...

  3. Inferring climate variability from skewed proxy records

    Science.gov (United States)

    Emile-Geay, J.; Tingley, M.

    2013-12-01

    Many paleoclimate analyses assume a linear relationship between the proxy and the target climate variable, and that both the climate quantity and the errors follow normal distributions. An ever-increasing number of proxy records, however, are better modeled using distributions that are heavy-tailed, skewed, or otherwise non-normal, on account of the proxies reflecting non-normally distributed climate variables, or having non-linear relationships with a normally distributed climate variable. The analysis of such proxies requires a different set of tools, and this work serves as a cautionary tale on the danger of making conclusions about the underlying climate from applications of classic statistical procedures to heavily skewed proxy records. Inspired by runoff proxies, we consider an idealized proxy characterized by a nonlinear, thresholded relationship with climate, and describe three approaches to using such a record to infer past climate: (i) applying standard methods commonly used in the paleoclimate literature, without considering the non-linearities inherent to the proxy record; (ii) applying a power transform prior to using these standard methods; (iii) constructing a Bayesian model to invert the mechanistic relationship between the climate and the proxy. We find that neglecting the skewness in the proxy leads to erroneous conclusions and often exaggerates changes in climate variability between different time intervals. In contrast, an explicit treatment of the skewness, using either power transforms or a Bayesian inversion of the mechanistic model for the proxy, yields significantly better estimates of past climate variations. We apply these insights in two paleoclimate settings: (1) a classical sedimentary record from Laguna Pallcacocha, Ecuador (Moy et al., 2002). Our results agree with the qualitative aspects of previous analyses of this record, but quantitative departures are evident and hold implications for how such records are interpreted, and

  4. Climate Change Indicators

    Science.gov (United States)

    Presents information, charts and graphs showing measured climate changes across 40 indicators related to greenhouse gases, weather and climate, oceans, snow and ice, heath and society, and ecosystems.

  5. Proxy indicators as measure of local economic dispositions in South ...

    African Journals Online (AJOL)

    Even though South Africa is in a more fortunate position with regard to the availability of such data, it also has data gaps, notably with regard to informal economic activities in the rural areas of the country. This exploratory article engages the use of proxy indicators to provide cues as to the state of a local economy.

  6. Proxy indicators as measure of local economic dispositions in South ...

    African Journals Online (AJOL)

    The growth of spare-part sales mirrors the behaviour of the national economy more accurately than used and new vehicles. BER: Retail Survey. (2005-2010). Used vehicles. 0.53. Spare Parts. 0.80. Banking-related proxy indicators. 13. House bonds. 0.43. Although some similarities exist between the national economy and ...

  7. Short-term indicators. Intensities as a proxy for savings

    Energy Technology Data Exchange (ETDEWEB)

    Boonekamp, P.G.M.; Gerdes, J. [ECN Policy Studies, Petten (Netherlands); Faberi, S. [Institute of Studies for the Integration of Systems ISIS, Rome (Italy)

    2013-12-15

    The ODYSSEE database on energy efficiency indicators (www.odyssee-indicators.org) has been set up to enable the monitoring and evaluation of realised energy efficiency improvements and related energy savings. The database covers the 27 EU countries as well as Norway and Croatia and data are available from 1990 on. This work contributes to the growing need for quantitative monitoring and evaluation of the impacts of energy policies and measures, both at the EU and national level, e.g. due to the Energy Services Directive and the proposed Energy Efficiency Directive. Because the underlying data become available only after some time, the savings figures are not always timely available. This is especially true for the ODEX efficiency indices per sector that rely on a number of indicators. Therefore, there is a need for so-called short-term indicators that become available shortly after the year has passed for which data are needed. The short term indicators do not replace the savings indicators but function as a proxy for the savings in the most recent year. This proxy value is faster available, but will be less accurate than the saving indicators themselves. The short term indicators have to be checked regularly with the ODEX indicators in order to see whether they can function still as a proxy.

  8. Identification of climatic state with limited proxy data

    Directory of Open Access Journals (Sweden)

    J. D. Annan

    2012-07-01

    Full Text Available We investigate the identifiability of the climate by limited proxy data. We test a data assimilation approach through perfect model pseudoproxy experiments, using a simple likelihood-based weighting based on the particle filtering process. Our experimental set-up enables us to create a massive 10 000-member ensemble at modest computational cost, thus enabling us to generate statistically robust results. We find that the method works well when data are sparse and imprecise, but in this case the reconstruction has a rather low accuracy as indicated by residual RMS errors. Conversely, when data are relatively plentiful and accurate, the estimate tracks the target closely, at least when considering the hemispheric mean. However, in this case, our prior ensemble size of 10 000 appears to be inadequate to correctly represent the true posterior, and the regional performance is poor. Using correlations to assess performance gives a more encouraging picture, with significant correlations ranging from about 0.3 when data are sparse to values over 0.7 when data are plentiful, but the residual RMS errors are substantial in all cases. Our results imply that caution is required in interpreting climate reconstructions, especially when considering the regional scale, as skill on this basis is markedly lower than on the large scale of hemispheric mean temperature.

  9. Near coast sedimentary stratigraphy as a proxy for climatic instability

    Science.gov (United States)

    McLivenny, J.

    2009-04-01

    Several studies have indicated a link between climatic deterioration and dune stability (Wilson 2002, Issar 2003, Dawson et al 2004). The frequency and magnitude of storms have been cited as a key variable in the stability of large dune systems. For the stratigraphy of dune systems to act as a regional climatic proxy there must be a good regional relationship between known climatic events and regionally correlated stratigraphic changes. Dunnet Bay in Caithness, Northern Scotland was chosen as a study site to look at the relationship between dune stability and climatic change during the late Holocene in Northern Scotland. Dunnet Bay was chosen for its physical attributes which make it an excellent natural sediment trap. Tucked in between headlands which act as barriers to long-shore transport the predominant movement of sediment there is straight onshore, with only minor amounts being lost to the sea. The immediate back-dune stratigraphy, colloquially known as "links", provided evidence of peat formation and dune stability. Stratigraphy was mapped using traditional field techniques and ground penetrating radar. The cores consisted mostly of massive layers of sand interleaved with peat. Sand layers were dated with optically stimulated luminescence (OSL) and interpreted as reflecting high wind energy regimes transporting sand inland. Peat layers were C14 dated and taken as representing climatic stability. Stratigraphy was mapped using hand auguring, percussion coring, and open sections. Ground penetrating radar was also used to look at the continuity of key layers. OSL dating in two open sections showed dates obtained from the first section (1790 AD ±70, 53 BC ± 100, 300 BC ± 100, 400 BC ± 100) mapped to the top of the second section (1800 AD ± 100, 1500 BC ± 200, 2900 BC ± 300) which was consistent with stratigraphy increasing sediment thickness towards the centre of the bay. The results were consistent with acquired C14 dates from selected peat layers. Taken

  10. Marine proxy evidence linking decadal North Pacific and Atlantic climate

    Energy Technology Data Exchange (ETDEWEB)

    Hetzinger, S. [University of Toronto Mississauga, CPS-Department, Mississauga, ON (Canada); Leibniz Institute of Marine Sciences, IFM-GEOMAR, Kiel (Germany); Halfar, J. [University of Toronto Mississauga, CPS-Department, Mississauga, ON (Canada); Mecking, J.V.; Keenlyside, N.S. [Leibniz Institute of Marine Sciences, IFM-GEOMAR, Kiel (Germany); University of Bergen, Geophysical Institute and Bjerknes Centre for Climate Research, Bergen (Norway); Kronz, A. [University of Goettingen, Geowissenschaftliches Zentrum, Goettingen (Germany); Steneck, R.S. [University of Maine, Darling Marine Center, Walpole, ME (United States); Adey, W.H. [Smithsonian Institution, Department of Botany, Washington, DC (United States); Lebednik, P.A. [ARCADIS U.S. Inc., Walnut Creek, CA (United States)

    2012-09-15

    Decadal- to multidecadal variability in the extra-tropical North Pacific is evident in 20th century instrumental records and has significant impacts on Northern Hemisphere climate and marine ecosystems. Several studies have discussed a potential linkage between North Pacific and Atlantic climate on various time scales. On decadal time scales no relationship could be confirmed, potentially due to sparse instrumental observations before 1950. Proxy data are limited and no multi-centennial high-resolution marine geochemical proxy records are available from the subarctic North Pacific. Here we present an annually-resolved record (1818-1967) of Mg/Ca variations from a North Pacific/Bering Sea coralline alga that extends our knowledge in this region beyond available data. It shows for the first time a statistically significant link between decadal fluctuations in sea-level pressure in the North Pacific and North Atlantic. The record is a lagged proxy for decadal-scale variations of the Aleutian Low. It is significantly related to regional sea surface temperature and the North Atlantic Oscillation (NAO) index in late boreal winter on these time scales. Our data show that on decadal time scales a weaker Aleutian Low precedes a negative NAO by several years. This atmospheric link can explain the coherence of decadal North Pacific and Atlantic Multidecadal Variability, as suggested by earlier studies using climate models and limited instrumental data. (orig.)

  11. How to combine sparse proxy data and coupled climate models

    Science.gov (United States)

    Paul, André; Schäfer-Neth, Christian

    2005-04-01

    We address the problem of reconstructing a global field from proxy data with sparse spatial sampling such as the MARGO (multi-proxy approach for the reconstruction of the glacial ocean surface) SST (sea-surface temperature) and δ18O c (oxygen-18/oxygen-16 isotope ratio preserved in fossil carbonate shells of planktic foraminifera) data. To this end, we propose to `assimilate' these data into coupled climate models by adjusting some of their parameters and optimizing the fit. In particular, we suggest to combine a forward model and an objective function that quantifies the misfit to the data. Because of their computational efficiency, earth system models of intermediate complexity are particularly well-suited for this purpose. We used one such model (the University of Victoria Earth System Climate Model) and carried out a series of sensitivity experiments by varying a single model parameter through changing the atmospheric CO2 concentration. The unanalyzed World Ocean Atlas SST and the observed sea-ice concentration served as present-day targets. The sparse data coverage as implied by the locations of 756 ocean sediment cores from the MARGO SST database was indeed sufficient to determine the best fit. As anticipated, it turned out to be the 365 ppm experiment. We also found that the 200 ppm experiment came surprisingly close to what is commonly expected for the Last Glacial Maximum ocean circulation. Our strategy has a number of advantages over more traditional mapping methods, e.g., there is no need to force the results of different proxies into a single map, because they can be compared to the model output one at a time, properly taking into account the different seasons of plankton growth or varying depth habitats. It can be extended to more model parameters and even be automated.

  12. Climate in Sweden during the past millennium - Evidence from proxy data, instrumental data and model simulations

    Energy Technology Data Exchange (ETDEWEB)

    Moberg, Anders; Gouirand, Isabelle; Schoning, Kristian; Wohlfarth, Barbara [Stockholm Univ. (Sweden). Dept. of Physical Geography and Quaternary Geology; Kjellstroem, Erik; Rummukainen, Markku [Swedish Meteorological and Hydrological Inst., Norrkoeping (Sweden). Rossby Centre; Jong, Rixt de [Lund Univ. (Sweden). Dept. of Quaternary Geology; Linderholm, Hans [Goeteborg Univ. (Sweden). Dept. of Earth Sciences; Zorita, Eduardo [GKSS Research Centre, Geesthacht (Germany)

    2006-12-15

    last millennium. Models, however, cannot be used to deduce the exact time evolution of climate variations, but they can provide relevant information in a statistical sense, for example by defining the limits within which climate naturally has varied. Uncertainties - and also advantages - of both empirical climate data and model simulations are discussed. A main conclusion is that there have been both relatively warm and cold past periods, as well as some relatively wet and dry periods during the past 1,000 to 2,000 years. It appears that the last 70-year period in Sweden was the warmest period over at least the last 500 years. Exactly how unusual the past few decades were can, however, not yet be established due to limitations of the proxy data. There are also indications that significant past changes in precipitation, river runoff and storminess have occurred, although available proxy data do not yet allow accurate quantitative estimations. The results of the present report will be used by SKB, along with other information, in the process of defining and describing future climate scenarios. They will also be used in evaluating the impact of climate on various processes related to repository safety, for example biosphere processes. To increase knowledge of past climate variations in Sweden for the last millennium, it seems necessary to develop additional climate proxy records with annual or at least decadal resolution. Long simulations with climate models may also be used in this context.

  13. A multiple-proxy approach to understanding rapid Holocene climate change in Southeast Greenland

    Science.gov (United States)

    Davin, S. H.; Bradley, R. S.; Balascio, N. L.; de Wet, G.

    2012-12-01

    The susceptibility of the Arctic to climate change has made it an excellent workshop for paleoclimatological research. Although there have been previous studies concerning climate variability carried out in the Arctic, there remains a critical dearth of knowledge due the limited number of high-resolution Holocene climate-proxy records available from this region. This gap skews our understanding of observed and predicted climate change, and fuels uncertainty both in the realms of science and policy. This study takes a comprehensive approach to tracking Holocene climate variability in the vicinity of Tasiilaq, Southeast Greenland using a ~5.6 m sediment core from Lower Sermilik Lake. An age-depth model for the core has been established using 8 radiocarbon dates, the oldest of which was taken at 4 m down core and has been been dated to approximately 6.2 kyr BP. The bottom meter of the core below the final radiocarbon date contains a transition from cobbles and coarse sand to organic-rich laminations, indicating the termination of direct glacial influence and therefore likely marking the end of the last glacial period in this region. The remainder of the core is similarly organic-rich, with light-to-dark brown laminations ranging from 0.5 -1 cm in thickness and riddled with turbidites. Using this core in tandem with findings from an on-site assessment of the geomorphic history of the locale we attempt to assess and infer the rapid climatic shifts associated with the Holocene on a sub-centennial scale. Such changes include the termination of the last glacial period, the Mid-Holocene Climatic Optimum, the Neoglacial Period, the Medieval Climatic Optimum, and the Little Ice Age. A multiple proxy approach including magnetic susceptibility, bulk organic geochemistry, elemental profiles acquired by XRF scanning, grain-size, and spectral data will be used to characterize the sediment and infer paleoclimate conditions. Additionally, percent biogenic silica by weight has been

  14. Climate indices for vulnerability assessments

    Energy Technology Data Exchange (ETDEWEB)

    Persson, Gunn; Baerring, Lars; Kjellstroem, Erik; Strandberg, Gustav; Rummuk ainen, Markku

    2007-08-15

    The demand is growing for practical information on climate projections and the impacts expected in different geographical regions and different sectors. It is a challenge to transform the vast amount of data produced in climate models into relevant information for climate change impact studies. Climate indices based on climate model data can be used as means to communicate climate change impact relations. In this report a vast amount of results is presented from a multitude of indices based on different regional climate scenarios. The regional climate scenarios described in this report show many similarities with previous scenarios in terms of general evolution and amplitude of future European climate change. The broad features are manifested in increases in warm and decreases in cold indices. Likewise are presented increases in wet indices in the north and dry indices in the south. Despite the extensive nature of the material presented, it does not cover the full range of possible climate change. We foresee a continued interactive process with stakeholders as well as continued efforts and updates of the results presented in the report.

  15. Phytolith indices as proxies of grass subfamilies on East African tropical mountains

    Science.gov (United States)

    Bremond, Laurent; Alexandre, Anne; Wooller, Matthew J.; Hély, Christelle; Williamson, David; Schäfer, Peter A.; Majule, Amos; Guiot, Joël

    2008-04-01

    The main objective of this paper is to provide researchers that investigate fossil phytolith assemblages and model/data comparisons a new tool for estimating C 3/C 4 grass composition over time. We tested the reliability of modern soil phytolith assemblages and phytolith indices for tracing the dominance of different grass subfamilies and tree cover density. We analyzed modern soil phytolith assemblages from sites over elevation gradients on Mount Kenya (Kenya), Mount Rungwe and around Lake Masoko (southern Tanzania). These data were compared with available botanical data. A phytolith index named Ic, proved to be an effective proxy of the proportions of Pooideae, Arundinoideae and Bambusoideae grasses (mainly C 3 grasses) versus Panicoideae grasses (mainly C 4 grasses), increasing with elevation in East-Africa. When tropical mountains are covered by open habitats (e.g . grasses and shrublands), Ic should be a reliable proxy of the C 3/C 4 grass composition. These results highlight the value of the phytolith index Ic, when interpreting paleo-environmental records from tropical mountains, to: 1) better understand past local and regional C 3/C 4 grass distributions and associated climatic changes and 2) increase the set of C 3/C 4 data available for model/data comparisons.

  16. Pseudo-proxy evaluation of climate field reconstruction methods of North Atlantic climate based on an annually resolved marine proxy network

    Science.gov (United States)

    Pyrina, Maria; Wagner, Sebastian; Zorita, Eduardo

    2017-10-01

    Two statistical methods are tested to reconstruct the interannual variations in past sea surface temperatures (SSTs) of the North Atlantic (NA) Ocean over the past millennium based on annually resolved and absolutely dated marine proxy records of the bivalve mollusk Arctica islandica. The methods are tested in a pseudo-proxy experiment (PPE) setup using state-of-the-art climate models (CMIP5 Earth system models) and reanalysis data from the COBE2 SST data set. The methods were applied in the virtual reality provided by global climate simulations and reanalysis data to reconstruct the past NA SSTs using pseudo-proxy records that mimic the statistical characteristics and network of Arctica islandica. The multivariate linear regression methods evaluated here are principal component regression and canonical correlation analysis. Differences in the skill of the climate field reconstruction (CFR) are assessed according to different calibration periods and different proxy locations within the NA basin. The choice of the climate model used as a surrogate reality in the PPE has a more profound effect on the CFR skill than the calibration period and the statistical reconstruction method. The differences between the two methods are clearer for the MPI-ESM model due to its higher spatial resolution in the NA basin. The pseudo-proxy results of the CCSM4 model are closer to the pseudo-proxy results based on the reanalysis data set COBE2. Conducting PPEs using noise-contaminated pseudo-proxies instead of noise-free pseudo-proxies is important for the evaluation of the methods, as more spatial differences in the reconstruction skill are revealed. Both methods are appropriate for the reconstruction of the temporal evolution of the NA SSTs, even though they lead to a great loss of variance away from the proxy sites. Under reasonable assumptions about the characteristics of the non-climate noise in the proxy records, our results show that the marine network of Arctica islandica can

  17. Pseudo-proxy evaluation of climate field reconstruction methods of North Atlantic climate based on an annually resolved marine proxy network

    Directory of Open Access Journals (Sweden)

    M. Pyrina

    2017-10-01

    Full Text Available Two statistical methods are tested to reconstruct the interannual variations in past sea surface temperatures (SSTs of the North Atlantic (NA Ocean over the past millennium based on annually resolved and absolutely dated marine proxy records of the bivalve mollusk Arctica islandica. The methods are tested in a pseudo-proxy experiment (PPE setup using state-of-the-art climate models (CMIP5 Earth system models and reanalysis data from the COBE2 SST data set. The methods were applied in the virtual reality provided by global climate simulations and reanalysis data to reconstruct the past NA SSTs using pseudo-proxy records that mimic the statistical characteristics and network of Arctica islandica. The multivariate linear regression methods evaluated here are principal component regression and canonical correlation analysis. Differences in the skill of the climate field reconstruction (CFR are assessed according to different calibration periods and different proxy locations within the NA basin. The choice of the climate model used as a surrogate reality in the PPE has a more profound effect on the CFR skill than the calibration period and the statistical reconstruction method. The differences between the two methods are clearer for the MPI-ESM model due to its higher spatial resolution in the NA basin. The pseudo-proxy results of the CCSM4 model are closer to the pseudo-proxy results based on the reanalysis data set COBE2. Conducting PPEs using noise-contaminated pseudo-proxies instead of noise-free pseudo-proxies is important for the evaluation of the methods, as more spatial differences in the reconstruction skill are revealed. Both methods are appropriate for the reconstruction of the temporal evolution of the NA SSTs, even though they lead to a great loss of variance away from the proxy sites. Under reasonable assumptions about the characteristics of the non-climate noise in the proxy records, our results show that the marine network of Arctica

  18. Reinterpreting climate proxy records from late Quaternary Chinese loess: A detailed OSL investigation

    Science.gov (United States)

    Stevens, Thomas; Thomas, David S. G.; Armitage, Simon J.; Lunn, Hannah R.; Lu, Huayu

    2007-01-01

    Numerous authors have utilised physical properties of Chinese loess and red clay deposits to develop apparently detailed and continuous past climate records from the Miocene into the Holocene. Many of these studies have further suggested that the principal climatic agent responsible for the aeolian emplacement and diagenesis of Chinese loess, the East Asian Monsoon, has fluctuated rapidly on millennial to sub-millennial timescales, in concert with dramatic changes in the North Atlantic (Dansgaard-Oeschger cycles and Heinrich events) and the Western Pacific (El Niño Southern Oscillation). Much of this evidence is based on reconstructions and age models that are tied to assumptions concerning the nature of loess sedimentation and diagenesis, for example, the belief that loess sedimentation can be viewed as essentially continuous. Some authors have however, cast doubt on these assumptions and suggest that the application of radiometric techniques may be required to determine their validity. Recent studies utilising Optically Stimulated Luminescence (OSL) methods have reinforced these doubts and here, OSL dates obtained at 10 cm intervals from three sites along a transect across the Chinese Loess Plateau have been used, in combination with climate proxy evidence, to test the existing assumptions that underpin many palaeoclimatic reconstructions from loess. In this way, the first time-continuous and independently dated late Quaternary climate reconstruction is developed from loess. The data indicate that sedimentation is episodic and that once emplaced, loess is prone to pedogenic disturbance, diagenetic modification and in some cases erosion. The relationships between proxies and sedimentation rates are also assessed and climatic interpretations based on different age models compared. The implications of these findings for reconstructions of climate from loess are explored and comparisons are made between the developed palaeoclimate records and evidence from ice and

  19. Late Oligocene to Late Miocene Antarctic Climate Reconstructions Using Molecular and Isotopic Biomarker Proxies

    Science.gov (United States)

    Duncan, B.; Mckay, R. M.; Bendle, J. A.; Naish, T.; Levy, R. H.; Ventura, G. T.; Moossen, H. M.; Krishnan, S.; Pagani, M.

    2015-12-01

    Major climate and environmental changes occurred during late Oligocene to the late Miocene when atmospheric CO2 ranged between 500 and 300ppm, indicating threshold response of Antarctic ice sheets and climate to relatively modest CO2 variations. This implies that the southern high latitudes are highly sensitive to feedbacks associated with changes in global ice sheet and sea-ice extent, as well as terrestrial and marine ecosystems. This study focuses on two key intervals during the evolution of the Antarctic Ice Sheet: (1) The Late Oligocene and the Oligocene/Miocene boundary, when the East Antarctic Ice Sheet expanded close to present day volume following an extended period of inferred warmth. (2) The Mid-Miocene Climate Optimum (MMCO ~17-15 Ma), a period of global warmth and moderately elevated CO2 (350->500 ppm) which was subsequently followed by rapid cooling at 14-13.5 Ma. Reconstructions of climate and ice sheet variability, and thus an understanding of the various feedbacks that occurred during these intervals, are hampered by a lack of temperature and hydroclimate proxy data from the southern high latitudes. We present proxy climate reconstructions using terrestrial and marine organic biomarkers that provide new insights into Antarctica's climate evolution, using Antarctic drill cores and outcrop samples from a range of depositional settings. Bacterial ether-lipids have been analysed to determine terrestrial mean annual temperatures and soil pH (via the methylation and cyclisation indexes of branched tetraethers - MBT and CBT, respectively). Tetraether-lipids of crenarchaeota found in marine sediments sampled from continental shelves around Antarctica have been used to derive sea surface temperatures using the TEX86 index. Compound specific stable isotopes on n-alkanes sourced from terrestrial plants have been analysed to investigate changes in the hydrological and carbon cycles.

  20. A method of separating local and large scale climate signals in coral proxies

    Science.gov (United States)

    Timm, O.; Ruprecht, E.; Pfeiffer, M.; Dullo, W.

    2003-04-01

    Coral proxies in the tropical and subtropical Indian Ocean show markedly different imprints of local climate factors. The oxygen isotopic composition (d18o) reflects a combination of SST and seawater properties. Both are the response to local effects and large scale climate variations in the oceans and the atmosphere, mainly due to air-sea fluxes. Consequently, an important step to large scale climate reconstructions from coral proxies is the separation of the individual local signal and the teleconnection with large scale climate modes such as the El Nino/Southern Oscillation (ENSO). The aim of this study is to present a method capable of extracting the large scale climate signal recorded in corals. Using multiple linear regression (MLR) techniques we first analyse the partial effects of local SST and precipitation minus evaporation on the coral d18o proxies. In a second step multivariate statistics are applied to the proxies and climate variables in order to distinguish between local signals and large scale variability in the proxies. Three d18o records from the Indian Ocean (Chagos, La Reunion, Seychelles) and the ENSO signal are used as an example demonstration. The method is also applied to Carribean corals (Guadeloupe). Preliminary results for the variability of these proxies and their relation to the North Atlantic Oscillation are given.

  1. Magnetic record associated with tree ring density: Possible climate proxy

    Directory of Open Access Journals (Sweden)

    Pruner Petr

    2007-03-01

    Full Text Available Abstract A magnetic signature of tree rings was tested as a potential paleo-climatic indicator. We examined wood from sequoia tree, located in Mountain Home State Forest, California, whose tree ring record spans over the period 600 – 1700 A.D. We measured low and high-field magnetic susceptibility, the natural remanent magnetization (NRM, saturation isothermal remanent magnetization (SIRM, and stability against thermal and alternating field (AF demagnetization. Magnetic investigation of the 200 mm long sequoia material suggests that magnetic efficiency of natural remanence may be a sensitive paleoclimate indicator because it is substantially higher (in average >1% during the Medieval Warm Epoch (700–1300 A.D. than during the Little Ice Age (1300–1850 A.D. where it is

  2. Climate as a social-cognitive construction of supervisory safety practices: scripts as proxy of behavior patterns.

    Science.gov (United States)

    Zohar, Dov; Luria, Gil

    2004-04-01

    Organizational climate research has focused on prediction of organizational outcomes rather than on climate as a social-cognitive mediator between environmental attributes and relevant outcomes. This article presents a model specifying that supervisory safety practices predict (safety) climate level and strength as moderated by leadership quality. Using supervisory scripts as proxy of practices, it is shown that script orientation indicative of safely priority predicted climate level, whereas script simplicity and cross-situational variability predicted climate strength. Transformational leadership mitigated these effects because of closer leader-member relationships. Safety climate partially mediated the relationship between supervisory scripts and injury rate during the 6-month period following climate and script measurement. Theoretical and methodological implications are discussed.

  3. A Multi-Proxy Perspective on Climate Variability in the Tropical Pacific over the Last Millennium

    Science.gov (United States)

    Quinn, Terrence; Partin, Jud; Thirumalai, Kaustubh; Hereid, Kelly; Maupin, Chris; Shen, Chuan-Chou; Taylor, Fred

    2014-05-01

    The southwest Pacific is a major source of tropical climate variability through heat and moisture exchanges associated with the Western Pacific Warm Pool (WPWP) and the South Pacific Convergence Zone (SPCZ). These variations are especially significant at the annual, ENSO, and multi-decadal timescales. Climate proxy records from the tropical Pacific must be used to extend records of SST, SSS, and rainfall variations into the pre-instrumental period. We highlight our recent efforts to quantitatively understand tropical climate variability over the last millennium using numerical simulations and climate proxy records (corals and stalagmites), the latter of which overlap with, and extend beyond the instrumental period. We investigate the use of individual foraminiferal analyses (IFA) in assessing past ENSO variability using numerical simulations. The simulation quantifies the sensitivity of IFA to ENSO amplitude and seasonal cycle amplitude (or a combination of both) at different locations in the tropical Pacific. Results indicate that IFA sensitivity towards ENSO is highest at the central equatorial Pacific surface ocean and the eastern equatorial Pacific (EEP) thermocline, whereas sensitivity towards the seasonal cycle is highest at the EEP surface ocean. We investigate tropical surface ocean variability using two recent coral-based climate reconstructions: a 233 yr record from Misima Island, Papua New Guinea (10.6° S, 152.8° E) and a 293 yr record from Olasana Island, Western Province, Solomon Islands (8.2° S, 157.2° E). The PNG coral record of monthly resolved δ18O and Sr/Ca variations spans the interval ~1414-1645. This record indicates that the surface ocean in this region experienced a small change in hydrologic balance with no change in temperature, extended periods of quiescence in El Niño activity, and no change in average amplitudes of El Niño events relative to signals captured in regional modern records. The Solomon coral δ18O record (1716

  4. Understanding north-western Mediterranean climate variability: a multi-proxy and multi-sequence approach based on wavelet analysis.

    Science.gov (United States)

    Azuara, Julien; Lebreton, Vincent; Jalali, Bassem; Sicre, Marie-Alexandrine; Sabatier, Pierre; Dezileau, Laurent; Peyron, Odile; Frigola, Jaime; Combourieu-Nebout, Nathalie

    2017-04-01

    Forcings and physical mechanisms underlying Holocene climate variability still remain poorly understood. Comparison of different paleoclimatic reconstructions using spectral analysis allows to investigate their common periodicities and helps to understand the causes of past climate changes. Wavelet analysis applied on several proxy time series from the Atlantic domain already revealed the first key-issues on the origin of Holocene climate variability. However the differences in duration, resolution and variance between the time-series are important issues for comparing paleoclimatic sequences in the frequency domain. This work compiles 7 paleoclimatic proxy records from 4 time-series from the north-western Mediterranean all ranging from 7000 to 1000 yrs cal BP: -pollen and clay mineral contents from the lagoonal sediment core PB06 recovered in southern France, -Sea Surface Temperatures (SST) derived from alkenones, concentration of terrestrial alkanes and their average chain length (ACL) from core KSGC-31_GolHo-1B recovered in the Gulf of Lion inner-shelf, - δ18O record from speleothems recovered in the Asiul Cave in north-western Spain, -grain size record from the deep basin sediment drift core MD99-2343 north of Minorca island. A comparison of their frequency content is proposed using wavelet analysis and cluster analysis of wavelet power spectra. Common cyclicities are assessed using cross-wavelet analysis. In addition, a new algorithm is used in order to propagate the age model errors within wavelet power spectra. Results are consistents with a non-stationnary Holocene climate variability. The Halstatt cycles (2000-2500 years) depicted in many proxies (ACL, errestrial alkanes and SSTs) demonstrate solar activity influence in the north-western Mediterranean climate. Cluster analysis shows that pollen and ACL proxies, both indicating changes in aridity, are clearly distinct from other proxies and share significant common periodicities around 1000 and 600 years

  5. Study of spectro-temporal variation in paleo-climatic marine proxy records using wavelet transformations

    Science.gov (United States)

    Pandey, Chhavi P.

    2017-10-01

    Wavelet analysis is a powerful mathematical and computational tool to study periodic phenomena in time series particu-larly in the presence of potential frequency changes in time. Continuous wavelet transformation (CWT) provides localised spectral information of the analysed dataset and in particular useful to study multiscale, nonstationary processes occurring over finite spatial and temporal domains. In the present work, oxygen-isotope ratio from the plantonic foraminifera species (viz. Globigerina bul-loides and Globigerinoides ruber) acquired from the broad central plateau of the Maldives ridge situated in south-eastern Arabian sea have been used as climate proxy. CWT of the time series generated using both the biofacies indicate spectro-temporal varia-tion of the natural climatic cycles. The dominant period resembles to the period of Milankovitch glacial-interglacial cycle. Apart from that, various other cycles are present in the time series. The results are in good agreement with the astronomical theory of paleoclimates and can provide better visualisation of Indian summer monsoon in the context of climate change.

  6. Technical Note: Correcting for signal attenuation from noisy proxy data in climate reconstructions

    Directory of Open Access Journals (Sweden)

    C. M. Ammann

    2010-04-01

    Full Text Available Regression-based climate reconstructions scale one or more noisy proxy records against a (generally short instrumental data series. Based on that relationship, the indirect information is then used to estimate that particular measure of climate back in time. A well-calibrated proxy record(s, if stationary in its relationship to the target, should faithfully preserve the mean amplitude of the climatic variable. However, it is well established in the statistical literature that traditional regression parameter estimation can lead to substantial amplitude attenuation if the predictors carry significant amounts of noise. This issue is known as "Measurement Error" (Fuller, 1987; Carroll et al., 2006. Climate proxies derived from tree-rings, ice cores, lake sediments, etc., are inherently noisy and thus all regression-based reconstructions could suffer from this problem. Some recent applications attempt to ward off amplitude attenuation, but implementations are often complex (Lee et al., 2008 or require additional information, e.g. from climate models (Hegerl et al., 2006, 2007. Here we explain the cause of the problem and propose an easy, generally applicable, data-driven strategy to effectively correct for attenuation (Fuller, 1987; Carroll et al., 2006, even at annual resolution. The impact is illustrated in the context of a Northern Hemisphere mean temperature reconstruction. An inescapable trade-off for achieving an unbiased reconstruction is an increase in variance, but for many climate applications the change in mean is a core interest.

  7. Technical Note: Correcting for signal attenuation from noisy proxy data in climate reconstructions

    KAUST Repository

    Ammann, C. M.

    2010-04-20

    Regression-based climate reconstructions scale one or more noisy proxy records against a (generally) short instrumental data series. Based on that relationship, the indirect information is then used to estimate that particular measure of climate back in time. A well-calibrated proxy record(s), if stationary in its relationship to the target, should faithfully preserve the mean amplitude of the climatic variable. However, it is well established in the statistical literature that traditional regression parameter estimation can lead to substantial amplitude attenuation if the predictors carry significant amounts of noise. This issue is known as "Measurement Error" (Fuller, 1987; Carroll et al., 2006). Climate proxies derived from tree-rings, ice cores, lake sediments, etc., are inherently noisy and thus all regression-based reconstructions could suffer from this problem. Some recent applications attempt to ward off amplitude attenuation, but implementations are often complex (Lee et al., 2008) or require additional information, e.g. from climate models (Hegerl et al., 2006, 2007). Here we explain the cause of the problem and propose an easy, generally applicable, data-driven strategy to effectively correct for attenuation (Fuller, 1987; Carroll et al., 2006), even at annual resolution. The impact is illustrated in the context of a Northern Hemisphere mean temperature reconstruction. An inescapable trade-off for achieving an unbiased reconstruction is an increase in variance, but for many climate applications the change in mean is a core interest.

  8. Climate change indicators in the United States

    Science.gov (United States)

    2010-04-01

    The U.S. Environmental Protection Agency (EPA) has published this report, Climate Change Indicators in the United States, to help readers interpret a set of important indicators to better understand climate change. The report presents 24 indicators, ...

  9. Variability of soil moisture proxies and hot days across the climate regimes of Australia

    Science.gov (United States)

    Holmes, A.; Rüdiger, C.; Mueller, B.; Hirschi, M.; Tapper, N.

    2017-07-01

    The frequency of extreme events such as heat waves are expected to increase due to the effect of climate change, particularly in semiarid regions of Australia. Recent studies have indicated a link between soil moisture deficits and heat extremes, focusing on the coupling between the two. This study investigates the relationship between the number of hot days (Tx90) and four soil moisture proxies (Standardized Precipitation Index, Antecedent Precipitation Index, Mount's Soil Dryness Index, and Keetch-Byram Drought Index), and how the strength of this relationship changes across various climate regimes within Australia. A strong anticorrelation between Tx90 and each moisture index is found, particularly for tropical savannas and temperate regions. However, the magnitude of the increase in Tx90 with decreasing moisture is strongest in semiarid and arid regions. It is also shown that the Tx90-soil moisture relationship strengthens during the El Niño phases of El Niño-Southern Oscillation in regions which are more sensitive to changes in soil moisture.

  10. Climate Proxies: An Inquiry-Based Approach to Discovering Climate Change on Antarctica

    Science.gov (United States)

    Wishart, D. N.

    2016-12-01

    An attractive way to advance climate literacy in higher education is to emphasize its relevance while teaching climate change across the curriculum to science majors and non-science majors. An inquiry-based pedagogical approach was used to engage five groups of students on a "Polar Discovery Project" aimed at interpreting the paleoclimate history of ice cores from Antarctica. Learning objectives and student learning outcomes were clearly defined. Students were assigned several exercises ranging from examination of Antarctic topography to the application of physical and chemical measurements as proxies for climate change. Required materials included base and topographic maps of Antarctica; graph sheets for construction of topographic cross-sectional profiles from profile lines of the Western Antarctica Ice Sheet (WAIS) Divide and East Antarctica; high-resolution photographs of Antarctic ice cores; stratigraphic columns of ice cores; borehole and glaciochemical data (i.e. anions, actions, δ18O, δD etc.); and isotope data on greenhouse gases (CH4, O2, N2) extracted from gas bubbles in ice cores. The methodology was to engage students in (2) construction of topographic profiles; (2) suggest directions for ice flow based on simple physics; (3) formulate decisions on suitable locations for drilling ice cores; (4) visual ice stratigraphy including ice layer counting; (5) observation of any insoluble particles (i.e. meteoritic and volcanic material); (6) analysis of borehole temperature profiles; and (7) the interpretation of several datasets to derive a paleoclimate history of these areas of the continent. The overall goal of the project was to improve the students analytical and quantitative skills; their ability to evaluate relationships between physical and chemical properties in ice cores, and to advance the understanding the impending consequences of climate change while engaging science, technology, engineering and mathematics (STEM). Student learning outcomes

  11. Hydroclimate variability in Scandinavia over the last millennium - insights from a climate model-proxy data comparison

    Science.gov (United States)

    Seftigen, Kristina; Goosse, Hugues; Klein, Francois; Chen, Deliang

    2017-12-01

    The integration of climate proxy information with general circulation model (GCM) results offers considerable potential for deriving greater understanding of the mechanisms underlying climate variability, as well as unique opportunities for out-of-sample evaluations of model performance. In this study, we combine insights from a new tree-ring hydroclimate reconstruction from Scandinavia with projections from a suite of forced transient simulations of the last millennium and historical intervals from the CMIP5 and PMIP3 archives. Model simulations and proxy reconstruction data are found to broadly agree on the modes of atmospheric variability that produce droughts-pluvials in the region. Despite these dynamical similarities, large differences between simulated and reconstructed hydroclimate time series remain. We find that the GCM-simulated multi-decadal and/or longer hydroclimate variability is systematically smaller than the proxy-based estimates, whereas the dominance of GCM-simulated high-frequency components of variability is not reflected in the proxy record. Furthermore, the paleoclimate evidence indicates in-phase coherencies between regional hydroclimate and temperature on decadal timescales, i.e., sustained wet periods have often been concurrent with warm periods and vice versa. The CMIP5-PMIP3 archive suggests, however, out-of-phase coherencies between the two variables in the last millennium. The lack of adequate understanding of mechanisms linking temperature and moisture supply on longer timescales has serious implications for attribution and prediction of regional hydroclimate changes. Our findings stress the need for further paleoclimate data-model intercomparison efforts to expand our understanding of the dynamics of hydroclimate variability and change, to enhance our ability to evaluate climate models, and to provide a more comprehensive view of future drought and pluvial risks.

  12. Hospital stay as a proxy indicator for severe injury in earthquakes: a retrospective analysis.

    Science.gov (United States)

    Zhao, Lu-Ping; Gerdin, Martin; Westman, Lina; Rodriguez-Llanes, Jose Manuel; Wu, Qi; van den Oever, Barbara; Pan, Liang; Albela, Manuel; Chen, Gao; Zhang, De-Sheng; Guha-Sapir, Debarati; von Schreeb, Johan

    2013-01-01

    Earthquakes are the most violent type of natural disasters and injuries are the dominant medical problem in the early phases after earthquakes. However, likely because of poor data availability, high-quality research on injuries after earthquakes is lacking. Length of hospital stay (LOS) has been validated as a proxy indicator for injury severity in high-income settings and could potentially be used in retrospective research of injuries after earthquakes. In this study, we assessed LOS as an adequate proxy indicator for severe injury in trauma survivors of an earthquake. A retrospective analysis was conducted using a database of 1,878 injured patients from the 2008 Wenchuan earthquake. Our primary outcome was severe injury, defined as a composite measure of serious injury or resource use. Secondary outcomes were serious injury and resource use, analysed separately. Non-parametric receiver operating characteristics (ROC) and area under the curve (AUC) analysis was used to test the discriminatory accuracy of LOS when used to identify severe injury. An 0.7earthquake survivors. However, LOS was found to be a proxy for major nonorthopaedic surgery and blood transfusion. These findings can be useful for retrospective research on earthquake-injured patients when detailed hospital records are not available.

  13. Multi-periodic climate dynamics: spectral analysis of long-term instrumental and proxy temperature records

    Science.gov (United States)

    Lüdecke, H.-J.; Hempelmann, A.; Weiss, C. O.

    2013-02-01

    The longest six instrumental temperature records of monthly means reach back maximally to 1757 AD and were recorded in Europe. All six show a V-shape, with temperature drop in the 19th and rise in the 20th century. Proxy temperature time series of Antarctic ice cores show this same characteristic shape, indicating this pattern as a global phenomenon. We used the mean of the six instrumental records for analysis by discrete Fourier transform (DFT), wavelets, and the detrended fluctuation analysis (DFA). For comparison, a stalagmite record was also analyzed by DFT. The harmonic decomposition of the abovementioned mean shows only six significant frequencies above periods over 30 yr. The Pearson correlation between the mean, smoothed by a 15-yr running average (boxcar) and the reconstruction using the six significant frequencies, yields r = 0.961. This good agreement has a > 99.9% confidence level confirmed by Monte Carlo simulations. It shows that the climate dynamics is governed at present by periodic oscillations. We find indications that observed periodicities result from intrinsic dynamics.

  14. Multi-periodic climate dynamics: spectral analysis of long-term instrumental and proxy temperature records

    Directory of Open Access Journals (Sweden)

    H.-J. Lüdecke

    2013-02-01

    Full Text Available The longest six instrumental temperature records of monthly means reach back maximally to 1757 AD and were recorded in Europe. All six show a V-shape, with temperature drop in the 19th and rise in the 20th century. Proxy temperature time series of Antarctic ice cores show this same characteristic shape, indicating this pattern as a global phenomenon. We used the mean of the six instrumental records for analysis by discrete Fourier transform (DFT, wavelets, and the detrended fluctuation analysis (DFA. For comparison, a stalagmite record was also analyzed by DFT. The harmonic decomposition of the abovementioned mean shows only six significant frequencies above periods over 30 yr. The Pearson correlation between the mean, smoothed by a 15-yr running average (boxcar and the reconstruction using the six significant frequencies, yields r = 0.961. This good agreement has a > 99.9% confidence level confirmed by Monte Carlo simulations. It shows that the climate dynamics is governed at present by periodic oscillations. We find indications that observed periodicities result from intrinsic dynamics.

  15. Climate indices of Iran under climate change

    Directory of Open Access Journals (Sweden)

    alireza kochaki

    2009-06-01

    Full Text Available Global warming will affect all climatic variables and particularly rainfall patterns. The purpose of present investigation was to predict climatic parameters of Iran under future climate change and to compare them with the present conditions. For this reason, UKMO General Circulation Model was used for the year 2025 and 2050. By running the model, minimum and maximum monthly temperature and also maximum monthly rainfall for the representative climate stations were calculated and finally the effects of climate change on these variables based on pre-determined scenarios was evaluated. The results showed that averaged over all stations, mean temperature increase for spring in the year 2025 and 2050 will be 3.1 and 3.9, for summer 3.8 and 4.7, for autumn 2.3 and 3 and for winter 2.0 and 2.4 ºC, respectively. This increase will be more pronounced from North to the South and from East to the West parts of the country. Mean decrease in autumn rainfall for the target years of 2025 and 2050 will be 8 and 11 percent, respectively. This decrease is negligible for summer months. Length of dry season for the years 2025 and 2050 will be increased, respectively up to 214 and 223 days due to combined effects of increased temperature and decreased rainfall.

  16. A multi-proxy reconstruction of Holocene climate change from Blessberg Cave, Germany

    Science.gov (United States)

    Breitenbach, Sebastian F. M.; Plessen, Birgit; Wenz, Sarah; Leonhardt, Jens; Tjallingii, Rik; Scholz, Denis; Jochum, Klaus Peter; Marwan, Norbert

    2016-04-01

    Although Holocene climate dynamics were relatively stable compared to glacial conditions, climatic changes had significant impact on ecosystems and human society on various timescales (Mayewski et al. 2004, Donges et al. 2015, Tan et al. 2015). Precious few high-resolution records on Holocene temperature and precipitation conditions in Central Europe are available (e.g., von Grafenstein et al. 1999, Fohlmeister et al. 2012). Here we present a speleothem-based reconstruction of past climate dynamics from Blessberg Cave, Thuringia, central Germany. Three calcitic stalagmites were recovered when the cave was discovered during tunneling operations in 2008. Samples BB-1, -2 and -3 were precisely dated by the 230Th/U-method, with errors between 10 and 160 years (2σ). The combined record covers large parts of the Holocene (10 - 0.4 ka BP). δ13C and δ18O were analysed at 100 μm resolution. To gain additional insights in infiltration conditions, Sr/Ca and S/Ca were measured on BB-1 and BB-3 using an Röntgenanalytik Eagle XXL μXRF scanner. Differences to other central European records (e.g., von Grafenstein et al. 1999, Fohlmeister et al. 2012) suggest complex interaction between multiple factors influencing speleothem δ18O in Blessberg Cave. Furthermore, no clear influence of the North Atlantic Oscillation on our proxies is found. However, a link across the N Atlantic realm is indicated by a centennial-scale correlation between Blessberg δ18O values and minerogenic input into lake SS1220 in Greenland over the last 5 ka (Olsen et al. 2012). In addition, recurrence analysis indicates an imprint of Atlantic Bond events on Blessberg δ18O values (Marwan et al. 2014), corroborating the suggested link with high northern latitudes. Larger runoff into the Greenland lake seems to be associated with lower δ18O, higher δ13C and S/Ca ratios, as well as lower Sr/Ca ratios in Blessberg Cave speleothems. This might be linked to lower local temperature and/or changes in

  17. Prompt Proxy Mapping of Flood Damaged Rice Fields Using MODIS-Derived Indices

    Directory of Open Access Journals (Sweden)

    Youngjoo Kwak

    2015-11-01

    Full Text Available Flood mapping, particularly hazard and risk mapping, is an imperative process and a fundamental part of emergency response and risk management. This paper aims to produce a flood risk proxy map of damaged rice fields over the whole of Bangladesh, where monsoon river floods are dominant and frequent, affecting over 80% of the total population. This proxy risk map was developed to meet the request of the government on a national level. This study represents a rapid, straightforward methodology for estimating rice-crop damage in flood areas of Bangladesh during the large flood from July to September 2007, despite the lack of primary data. We improved a water detection algorithm to achieve a better discrimination capacity to discern flood areas by using a modified land surface water index (MLSWI. Then, rice fields were estimated utilizing a hybrid rice field map from land-cover classification and MODIS-derived indices, such as the normalized difference vegetation index (NDVI and enhanced vegetation index (EVI. The results showed that the developed method is capable of providing instant, comprehensive, nationwide mapping of flood risks, such as rice field damage. The detected flood areas and damaged rice fields during the 2007 flood were verified by comparing them with the Advanced Land Observing Satellite (ALOS AVNIR-2 images (a 10 m spatial resolution and in situ field survey data with moderate agreement (K = 0.57.

  18. Statistical framework for evaluation of climate model simulations by use of climate proxy data from the last millennium – Part 2: A pseudo-proxy study addressing the amplitude of solar forcing

    Directory of Open Access Journals (Sweden)

    A. Hind

    2012-08-01

    Full Text Available The statistical framework of Part 1 (Sundberg et al., 2012, for comparing ensemble simulation surface temperature output with temperature proxy and instrumental records, is implemented in a pseudo-proxy experiment. A set of previously published millennial forced simulations (Max Planck Institute – COSMOS, including both "low" and "high" solar radiative forcing histories together with other important forcings, was used to define "true" target temperatures as well as pseudo-proxy and pseudo-instrumental series. In a global land-only experiment, using annual mean temperatures at a 30-yr time resolution with realistic proxy noise levels, it was found that the low and high solar full-forcing simulations could be distinguished. In an additional experiment, where pseudo-proxies were created to reflect a current set of proxy locations and noise levels, the low and high solar forcing simulations could only be distinguished when the latter served as targets. To improve detectability of the low solar simulations, increasing the signal-to-noise ratio in local temperature proxies was more efficient than increasing the spatial coverage of the proxy network. The experiences gained here will be of guidance when these methods are applied to real proxy and instrumental data, for example when the aim is to distinguish which of the alternative solar forcing histories is most compatible with the observed/reconstructed climate.

  19. Linking coral river runoff proxies with climate variability, hydrology and land-use in Madagascar catchments.

    Science.gov (United States)

    Maina, Joseph; de Moel, Hans; Vermaat, Jan E; Bruggemann, J Henrich; Guillaume, Mireille M M; Grove, Craig A; Madin, Joshua S; Mertz-Kraus, Regina; Zinke, Jens

    2012-10-01

    Understanding the linkages between coastal watersheds and adjacent coral reefs is expected to lead to better coral reef conservation strategies. Our study aims to examine the main predictors of environmental proxies recorded in near shore corals and therefore how linked near shore reefs are to the catchment physical processes. To achieve these, we developed models to simulate hydrology of two watersheds in Madagascar. We examined relationships between environmental proxies derived from massive Porites spp. coral cores (spectral luminescence and barium/calcium ratios), and corresponding time-series (1950-2006) data of hydrology, climate, land use and human population growth. Results suggest regional differences in the main environmental drivers of reef sedimentation: on annual time-scales, precipitation, river flow and sediment load explained the variability in coral proxies of river discharge for the northeast region, while El Niño-Southern Oscillation (ENSO) and temperature (air and sea surface) were the best predictors in the southwest region. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Molecular proxies for climate maladaptation in a long-lived tree (Pinus pinaster Aiton, Pinaceae).

    Science.gov (United States)

    Jaramillo-Correa, Juan-Pablo; Rodríguez-Quilón, Isabel; Grivet, Delphine; Lepoittevin, Camille; Sebastiani, Federico; Heuertz, Myriam; Garnier-Géré, Pauline H; Alía, Ricardo; Plomion, Christophe; Vendramin, Giovanni G; González-Martínez, Santiago C

    2015-03-01

    Understanding adaptive genetic responses to climate change is a main challenge for preserving biological diversity. Successful predictive models for climate-driven range shifts of species depend on the integration of information on adaptation, including that derived from genomic studies. Long-lived forest trees can experience substantial environmental change across generations, which results in a much more prominent adaptation lag than in annual species. Here, we show that candidate-gene SNPs (single nucleotide polymorphisms) can be used as predictors of maladaptation to climate in maritime pine (Pinus pinaster Aiton), an outcrossing long-lived keystone tree. A set of 18 SNPs potentially associated with climate, 5 of them involving amino acid-changing variants, were retained after performing logistic regression, latent factor mixed models, and Bayesian analyses of SNP-climate correlations. These relationships identified temperature as an important adaptive driver in maritime pine and highlighted that selective forces are operating differentially in geographically discrete gene pools. The frequency of the locally advantageous alleles at these selected loci was strongly correlated with survival in a common garden under extreme (hot and dry) climate conditions, which suggests that candidate-gene SNPs can be used to forecast the likely destiny of natural forest ecosystems under climate change scenarios. Differential levels of forest decline are anticipated for distinct maritime pine gene pools. Geographically defined molecular proxies for climate adaptation will thus critically enhance the predictive power of range-shift models and help establish mitigation measures for long-lived keystone forest trees in the face of impending climate change. Copyright © 2015 by the Genetics Society of America.

  1. Statistical framework for evaluation of climate model simulations by use of climate proxy data from the last millennium – Part 1: Theory

    Directory of Open Access Journals (Sweden)

    R. Sundberg

    2012-08-01

    Full Text Available A statistical framework for comparing the output of ensemble simulations from global climate models with networks of climate proxy and instrumental records has been developed, focusing on near-surface temperatures for the last millennium. This framework includes the formulation of a joint statistical model for proxy data, instrumental data and simulation data, which is used to optimize a quadratic distance measure for ranking climate model simulations. An essential underlying assumption is that the simulations and the proxy/instrumental series have a shared component of variability that is due to temporal changes in external forcing, such as volcanic aerosol load, solar irradiance or greenhouse gas concentrations. Two statistical tests have been formulated. Firstly, a preliminary test establishes whether a significant temporal correlation exists between instrumental/proxy and simulation data. Secondly, the distance measure is expressed in the form of a test statistic of whether a forced simulation is closer to the instrumental/proxy series than unforced simulations. The proposed framework allows any number of proxy locations to be used jointly, with different seasons, record lengths and statistical precision. The goal is to objectively rank several competing climate model simulations (e.g. with alternative model parameterizations or alternative forcing histories by means of their goodness of fit to the unobservable true past climate variations, as estimated from noisy proxy data and instrumental observations.

  2. Multi-periodic climate dynamics: spectral analysis of long-term instrumental and proxy temperature records

    OpenAIRE

    H.-J. Lüdecke; A. Hempelmann; Weiss, C. O.

    2012-01-01

    The longest six instrumental temperature records of monthly means reach back maximally to 1757 AD and were recorded in Europe. All six show a V-shape, with temperature drop in the 19th and rise in the 20th century. Proxy temperature time series of Antarctic ice cores show this same characteristic shape, indicating this pattern as a global phenomenon. We used the mean of the 6 instrumental records for analysis by discrete Fourier transformation (DFT), wavelets, and the detrended fluctuati...

  3. Multi-periodic climate dynamics: spectral analysis of long-term instrumental and proxy temperature records

    OpenAIRE

    Lüdecke, H.-J.; A. Hempelmann; Weiss, C. O.

    2013-01-01

    The longest six instrumental temperature records of monthly means reach back maximally to 1757 AD and were recorded in Europe. All six show a V-shape, with temperature drop in the 19th and rise in the 20th century. Proxy temperature time series of Antarctic ice cores show this same characteristic shape, indicating this pattern as a global phenomenon. We used the mean of the six instrumental records for analysis by discrete Fourier transform (DFT), wavelets, and the detren...

  4. Mid-late Holocene climate, demography, and cultural dynamics in Iberia: A multi-proxy approach

    Science.gov (United States)

    Lillios, Katina T.; Blanco-González, Antonio; Drake, Brandon Lee; López-Sáez, José Antonio

    2016-03-01

    Despite increasing interest in the relationship between culture transformation and abrupt climate change, their complexities are poorly understood. The local impact of global environmental fluctuations depends on multiple factors, and their effects on societal collapse are often assumed rather than demonstrated. One of the major changes in west European later prehistory was the Copper to Bronze Age transition, contemporaneous with the 4.2 ky cal. BP event. This article offers a multi-dimensional insight into this historical process in the Iberian Peninsula from a multi-proxy and comparative perspective. Three study areas, representative of diverse ecological settings and historical trajectories, are compared. Using radiocarbon dates, 13C discrimination (Δ13C) values on C3 plants, and high-resolution palynological records as palaeoclimatic and palaeodemographic proxies, this study tracks the uneven signals of Holocene climate. The wettest Northwest region features the most stable trend lines, whereas the Southwest exhibits an abrupt decrease in its demographic signals c. 4500 cal. BP, which is then followed by a subsequent rise in the neighbouring Southeast. These lines of evidence suggest the possibility, never previously noted, of demic migration from the Southwest to the Southeast in the Early Bronze Age as a contributing factor to the cultural dynamics of southern Iberia.

  5. Climate Change or Land Use Dynamics: Do We Know What Climate Change Indicators Indicate?

    OpenAIRE

    Clavero Pineda, Miguel; Villero, Daniel; Brotons, Lluís

    2011-01-01

    Different components of global change can have interacting effects on biodiversity and this may influence our ability to detect the specific consequences of climate change through biodiversity indicators. Here, we analyze whether climate change indicators can be affected by land use dynamics that are not directly determined by climate change. To this aim, we analyzed three community-level indicators of climate change impacts that are based on the optimal thermal environment and average lat...

  6. Indicators of climate impacts for forests: recommendations for the US National Climate Assessment indicators system

    Science.gov (United States)

    Linda S. Heath; Sarah M. Anderson; Marla R. Emery; Jeffrey A. Hicke; Jeremy Littell; Alan Lucier; Jeffrey G. Masek; David L. Peterson; Richard Pouyat; Kevin M. Potter; Guy Robertson; Jinelle Sperry; Andrzej Bytnerowicz; Sarah Jovan; Miranda H. Mockrin; Robert Musselman; Bethany K. Schulz; Robert J. Smith; Susan I. Stewart

    2015-01-01

    The Third National Climate Assessment (NCA) process for the United States focused in part on developing a system of indicators to communicate key aspects of the physical climate, climate impacts, vulnerabilities, and preparedness to inform decisionmakers and the public. Initially, 13 active teams were formed to recommend indicators in a range of categories, including...

  7. Mobile phone call data as a regional socio-economic proxy indicator.

    Directory of Open Access Journals (Sweden)

    Sanja Šćepanović

    Full Text Available The advent of publishing anonymized call detail records opens the door for temporal and spatial human dynamics studies. Such studies, besides being useful for creating universal models for mobility patterns, could be also used for creating new socio-economic proxy indicators that will not rely only on the local or state institutions. In this paper, from the frequency of calls at different times of the day, in different small regional units (sub-prefectures in Côte d'Ivoire, we infer users' home and work sub-prefectures. This division of users enables us to analyze different mobility and calling patterns for the different regions. We then compare how those patterns correlate to the data from other sources, such as: news for particular events in the given period, census data, economic activity, poverty index, power plants and energy grid data. Our results show high correlation in many of the cases revealing the diversity of socio-economic insights that can be inferred using only mobile phone call data. The methods and the results may be particularly relevant to policy-makers engaged in poverty reduction initiatives as they can provide an affordable tool in the context of resource-constrained developing economies, such as Côte d'Ivoire's.

  8. Climate change or land use dynamics: do we know what climate change indicators indicate?

    Directory of Open Access Journals (Sweden)

    Miguel Clavero

    Full Text Available Different components of global change can have interacting effects on biodiversity and this may influence our ability to detect the specific consequences of climate change through biodiversity indicators. Here, we analyze whether climate change indicators can be affected by land use dynamics that are not directly determined by climate change. To this aim, we analyzed three community-level indicators of climate change impacts that are based on the optimal thermal environment and average latitude of the distribution of bird species present at local communities. We used multiple regression models to relate the variation in climate change indicators to: i environmental temperature; and ii three landscape gradients reflecting important current land use change processes (land abandonment, fire impacts and urbanization, all of them having forest areas at their positive extremes. We found that, with few exceptions, landscape gradients determined the figures of climate change indicators as strongly as temperature. Bird communities in forest habitats had colder-dwelling bird species with more northern distributions than farmland, burnt or urban areas. Our results show that land use changes can reverse, hide or exacerbate our perception of climate change impacts when measured through community-level climate change indicators. We stress the need of an explicit incorporation of the interactions between climate change and land use dynamics to understand what are current climate change indicators indicating and be able to isolate real climate change impacts.

  9. Climate inferences between paleontological, geochemical, and geophysical proxies in Late Pleistocene lacustrine sediments from Summer Lake, Oregon, western Great Basin

    Science.gov (United States)

    Heaton, Eric; Thompson, Greg; Negrini, Rob; Wigand, Peter

    2016-04-01

    Paleontological, geochemical, and geophysical data from western Great Basin pluvial Summer Lake, Oregon have established a high resolution paleoclimate record during the late Pleistocene Mono Lake Excursion (~34.75 ka), Dansgaard-Oeschger interstadials 6-8, and the end of Heinrich Even 4 (~38 ka). Proxies of grain-size, magnetic susceptibility, carbon/nitrogen ratio, ostracode analysis and palynology from a depocenter core show new results with improved age control regarding high amplitude, high frequency changes in lake level, lake temperature, and regional precipitation and temperature which correspond directly with colder/warmer and respectively drier/wetter climates as documented with Northern Atlantic Greenland ice core data. Results from geophysical and geochemical analysis, and the presence of ostracode Cytherissa lacustris consistently demonstrate the correspondence of low lake conditions and colder water temperatures during Dansgaard-Oeschger stadials and the Mono Lake Excursion. The opposite holds true during interstadials. Smaller grain size, increases in carbon/nitrogen ratio and consistent absence of C. lacustris suggest periods of increased discharge into the lake, increased lake level, and warmer water temperatures. Warmer/wetter climate conditions are confirmed during interstadials 7 and 8 from pollen analysis. Existence of Atriplex, Rosaceae, Chrysothamnus and Ambrosia, and pollen ratios of Juniperus/Dip Pinus and (Rosaceae+Atriplex+Poaceae+Chrysothamnus+Ambrosia)/(Pinus+Picea+T. mertensiana+Sarcobatus) suggest warmer/wetter semi-arid woodland conditions during interstadials 7 and 8. This contrasts with absences in these pollens and pollen ratios indicating colder/drier continental montane woodland conditions during stadials and the Mono Lake Excursion. Increases in Juniper/Dip Pinus ratio suggest a warmer/wetter climate during interstadial 6 however additional proxies do not demonstrate comparative warmer/wetter climate, deeper lake level or

  10. Tales from the South (and West) Pacific in the Common Era: A Climate Proxy Perspective (Invited)

    Science.gov (United States)

    Quinn, T. M.; Taylor, F. W.; Partin, J. W.; Maupin, C. R.; Hereid, K. A.; Gorman, M. K.

    2010-12-01

    The southwest Pacific is a major source of tropical climate variability through heat and moisture exchanges associated with the Western Pacific Warm Pool (WPWP) and the South Pacific Convergence Zone (SPCZ). These variations are especially significant at the annual, interannual (El Niño-Southern Oscillation, ENSO), and multi-decadal timescales. Gridded SST data products are available in the pre-satellite era in this region for the past ~130 years, although data density is a significant issue for the older half of these records. Time series of salinity (SSS) and rainfall from this region are exceedingly rare. Thus, climate proxy records must be used to reconstruct SST, SSS, and rainfall variations in the Common Era (CE) in the tropical Pacific. The analytical laboratory for paleoclimate studies at UT has focused its research efforts into producing climate proxy time series from southwest tropical Pacific using modern and fossil corals, and speleothems. Our most recent results are summarized in this presentation, although much of this work is still in progress. Coral climate records have been generated from Sabine Bank, Vanuatu (16°S, 166°E) and Misima Island, Papua New Guinea (10.6°S, 152.8°E). The Vanuatu coral record of monthly resolved Sr/Ca variations extends back to the late 18th century. All strong ENSO warm phase events of the 20th century observed in the instrumental record are also observed in the coral record. We note that several ENSO warm phase events in the 19th century portion of the coral record are comparable in size to that recorded in response to the 1982/1983 and 1997/1998 events. The Misima coral record of monthly resolved δ18O and Sr/Ca variations spans the interval ~1414-1645 CE — the heart of the Little Ice Age. Amplitude modulation of interannual variability is observed in this LIA record, much like what is observed during the relatively quiescent period of 1920-1950 in the 20th century instrumental and proxy records of ENSO. However

  11. Investigating Forest Inventory and Analysis-collected tree-ring data from Utah as a proxy for historical climate

    Science.gov (United States)

    R. Justin DeRose; W. Shih-Yu (Simon) Wang; John D. Shaw

    2012-01-01

    Increment cores collected as part of the periodic inventory in the Intermountain West were examined for their potential to represent growth and be a proxy for climate (precipitation) over a large region (Utah). Standardized and crossdated time-series created from pinyon pine (n=249) and Douglas-fir (n=274) increment cores displayed spatiotemporal patterns in growth...

  12. Fingerprinting of soil organic matter as a proxy for assessing climate and vegetation changes in last interglacial paleosols (Veldwezelt, Belgium)

    NARCIS (Netherlands)

    Vancampenhout, K.; Wouters, K.; Caus, A.; Buurman, P.; Swennen, R.; Deckers, J.

    2008-01-01

    Soil characteristics in palaeosols are an important source of information on past climate and vegetation. Fingerprinting of soil organic matter (SOM) by pyrolysis-GC/MS is assessed as a proxy for palaeo-reconstruction in the complex of humic layers on top of the Rocourt pedosequence in the

  13. Reliability and usability of tourism climate indices

    Directory of Open Access Journals (Sweden)

    Ghislain Dubois

    2016-04-01

    Full Text Available Abstract Tourism climate indices (TCI are commonly used to describe the climate conditions suitable for tourism activities, from the planning, investment or daily operations perspectives. A substantial amount of research has been carried out, in particular with respect to new indices formulae adapted to specific tourism products, and parameters and their weighting, taking into account surveys on the stated preferences of tourists, especially in terms of comfort. This paper illustrates another field of research, which seeks to better understand the different sources of uncertainty associated with indices. Indeed, slight differences in formula thresholds, variations in computation methods, and also the use of multimodel ensembles create nuances that affect the ways in which indices projections are usually presented. Firstly, we assess the impact of differences in preference surveys on the definition of indices thresholds, in particular for thermal comfort. Secondly, we compare computation methods for France, showing the need to better specify detailed data sources and their use to ensure the comparability of results. Thirdly, using multimodel ensembles for the Mediterranean basin, we assess the uncertainty inherent in long-term projections, which are used in modelling the economic impact of climate change. This paper argues in favour of a more cautious use of tourism comfort indices, with more consideration given to the robustness of data (validation, debiasing, uncertainty assessment, etc. and users’ needs, from the climate services perspective.

  14. A multi-proxy perspective on millennium-long climate variability in the Southern Pyrenees

    Science.gov (United States)

    Morellón, M.; Pérez-Sanz, A.; Corella, J. P.; Büntgen, U.; Catalán, J.; González-Sampériz, P.; González-Trueba, J. J.; López-Sáez, J. A.; Moreno, A.; Pla-Rabes, S.; Saz-Sánchez, M. Á.; Scussolini, P.; Serrano, E.; Steinhilber, F.; Stefanova, V.; Vegas-Vilarrúbia, T.; Valero-Garcés, B.

    2012-03-01

    This paper reviews multi-proxy paleoclimatic reconstructions with robust age-control derived from lacustrine, dendrochronological and geomorphological records and characterizes the main environmental changes that occurred in the Southern Pyrenees during the last millennium. Warmer and relatively arid conditions prevailed during the Medieval Climate Anomaly (MCA, ca. 900-1300 AD), with a significant development of xerophytes and Mediterranean vegetation and limited deciduous tree formations (mesophytes). The Little Ice Age (LIA, 1300-1800 AD) was generally colder and moister, with an expansion of deciduous taxa and cold-adapted montane conifers. Two major phases occurred within this period: (i) a transition MCA-LIA, characterized by fluctuating, moist conditions and relatively cold temperatures (ca. 1300 and 1600 AD); and (ii) a second period, characterized by the coldest and most humid conditions, coinciding with maximum (recent) glacier advances (ca. 1600-1800 AD). Glaciers retreated after the LIA when warmer and more arid conditions dominated, interrupted by a short-living cooling episode during the late 19th to early 20th centuries. Some records suggest a response to solar activity with colder and slightly moister conditions during solar minima. Centennial-scale hydrological fluctuations are in phase with reconstructions of NAO variability, which appears to be one of the main climate mechanisms influencing rainfall variations in the region during the last millennium.

  15. A multi-proxy perspective on millennium-long climate variability in the Southern Pyrenees

    Directory of Open Access Journals (Sweden)

    M. Morellón

    2012-03-01

    Full Text Available This paper reviews multi-proxy paleoclimatic reconstructions with robust age-control derived from lacustrine, dendrochronological and geomorphological records and characterizes the main environmental changes that occurred in the Southern Pyrenees during the last millennium. Warmer and relatively arid conditions prevailed during the Medieval Climate Anomaly (MCA, ca. 900–1300 AD, with a significant development of xerophytes and Mediterranean vegetation and limited deciduous tree formations (mesophytes. The Little Ice Age (LIA, 1300–1800 AD was generally colder and moister, with an expansion of deciduous taxa and cold-adapted montane conifers. Two major phases occurred within this period: (i a transition MCA–LIA, characterized by fluctuating, moist conditions and relatively cold temperatures (ca. 1300 and 1600 AD; and (ii a second period, characterized by the coldest and most humid conditions, coinciding with maximum (recent glacier advances (ca. 1600–1800 AD. Glaciers retreated after the LIA when warmer and more arid conditions dominated, interrupted by a short-living cooling episode during the late 19th to early 20th centuries. Some records suggest a response to solar activity with colder and slightly moister conditions during solar minima. Centennial-scale hydrological fluctuations are in phase with reconstructions of NAO variability, which appears to be one of the main climate mechanisms influencing rainfall variations in the region during the last millennium.

  16. The conceptualization and measurement of cognitive reserve using common proxy indicators: Testing some tenable reflective and formative models.

    Science.gov (United States)

    Ikanga, Jean; Hill, Elizabeth M; MacDonald, Douglas A

    2017-02-01

    The examination of cognitive reserve (CR) literature reveals a lack of consensus regarding conceptualization and pervasive problems with its measurement. This study aimed at examining the conceptual nature of CR through the analysis of reflective and formative models using eight proxies commonly employed in the CR literature. We hypothesized that all CR proxies would significantly contribute to a one-factor reflective model and that educational and occupational attainment would produce the strongest loadings on a single CR factor. The sample consisted of 149 participants (82 male/67 female), with 18.1 average years of education and ages of 45-99 years. Participants were assessed for eight proxies of CR (parent socioeconomic status, intellectual functioning, level of education, health literacy, occupational prestige, life leisure activities, physical activities, and spiritual and religious activities). Primary statistical analyses consisted of confirmatory factor analysis (CFA) to test reflective models and structural equation modeling (SEM) to evaluate multiple indicators multiple causes (MIMIC) models. CFA did not produce compelling support for a unitary CR construct when using all eight of our CR proxy variables in a reflective model but fairly cogent evidence for a one-factor model with four variable proxies. A second three-factor reflective model based upon an exploratory principal components analysis of the eight proxies was tested using CFA. Though all eight indicators significantly loaded on their assigned factors, evidence in support of overall model fit was mixed. Based upon the results involving the three-factor reflective model, two alternative formative models were developed and evaluated. While some support was obtained for both, the model in which the formative influences were specified as latent variables appeared to best account for the contributions of all eight proxies to the CR construct. While the findings provide partial support for our

  17. Climate fluctuations in the Czech Lands from AD 1500 compiled from various proxies

    Science.gov (United States)

    Dobrovolný, Petr; Brázdil, Rudolf; Možný, Martin; Trnka, Miroslav; Řezníčková, Ladislava; Kotyza, Oldřich; Valášek, Hubert; Dolák, Lukáš

    2017-04-01

    The territory of the Czech Lands (recent Czech Republic) belongs to European areas well covered by dedrochronological, documentary and instrumental data which can be used for climate reconstructions for the last c. 500 years, i.e. for description of climate fluctuations during the greater part of the Little Ice Age (LIA) and the subsequent period of the recent Global Warming. Synthesis of various existing reconstructions should help to create more consistent description of climate variability in that period in Central Europe. The contribution starts from characteristic of the basic features of three existing data sources and a general method of climate reconstruction. Monthly, seasonal and annual climate reconstructions based on different data are presented: a) temperature reconstructions derived from series of temperature indices, winter wheat harvest days and grape harvest days; b) precipitation reconstructions derived from series of precipitation indices and fir tree-rings; c) drought indices (SPI, SPEI, Z-index and PDSI) reconstructions derived from series of fir tree-rings, grape harvest days and documentary-based temperature and precipitation reconstructions. Basic features of past c. 500 years are represented by various time intervals of cooler and warmer climate on the one hand and wetter and drier climate on the other. Examples of such particularly warmer and drier period can be the 1530s (with extreme 1540 year) or colder and wetter conditions during the 1590s and 1690s. Outstanding extreme weather events during LIA in Central Europe are briefly mentioned and our findings are discussed with respect to climate fluctuations and forcings in wider European context. (This study was supported by Czech Science Foundation, project nos. 13-04291S and 17-10026S).

  18. Decade to centennial resolution hydrogen isotopic record of climate change from southern New England for the past 16 kyr: proxy validation and multi-proxy comparisons

    Science.gov (United States)

    Huang, Y.; Gao, L.; Hou, J.; Shuman, B. N.; Oswald, W.; Foster, D.

    2009-12-01

    Open system lakes in New England offer excellent archives of precipitation isotopic ratios that yield quantitative paleoclimate information. We have demonstrated previously from a lake sediment transect that hydrogen isotopic ratios of a middle-chain length fatty acid, behenic acid (BA), faithfully record precipitation isotopic ratios. We hypothesized that mid-chain n-alkyl lipids in these small lakes were primarily derived from aquatic plants that record lake water isotopic ratios. To test this hypothesis, we conducted systematic and extensive sampling of both terrestrial and aquatic plants over the past two years at two typical kettle hole lakes, Blood Pond and Rocky Pond, MA, and used a linear algebra approach to delineate percentage inputs of aquatic and terrestrial plant contributions to mid-chain n-alkyl lipids. Our results demonstrate that >92 % of the mid-chain n-alkyl lipids is derived from submerged and floating aquatic macrophytes. Our new data provide a solid basis for the application of behenic hydrogen isotopic ratios as a paleoclimate proxy from small lakes. We will present a decadal to centennial scale 16 kyr record of BA hydrogen isotopic ratios from Blood Pond, and will discuss the results in light of published pollen and lake level data. Overall, our hydrogen isotopic record is fully consistent with regional climate scenarios, including the distinctive warming at B-A events, abrupt cooling at YD event, and transition from glacial to Holcoene climate conditions. However, our high-solution isotopic data provides important new insights concerning abrupt regional climate variability. We demonstrate that the New England climate is exceptionally senstive to AMOC changes and solar forcing and that many of the abrupt climate fluctuations exert major impacts on terrestrial ecosystems, hydrology and lake levels.

  19. Holocene Climate, Fire and Vegetation Change Inferred from Lacustrine Proxies in the Tropical Andes, Laguna Yanacocha, SE Peru

    Science.gov (United States)

    Axford, Y.; Isaacson, M.; Matthews-Bird, F.; Schellinger, G. C.; Carrio, C. L.; Kelly, M. A.; Lowell, T. V.; Beal, S. A., Jr.; Stroup, J. S.; Tapia, P. M.

    2016-12-01

    We present a 12,000-year long paleoenvironmental reconstruction from a small high-elevation lake in southeastern Peru. Climate and environmental change are inferred from chironomid species assemblages, charcoal abundance, size and morphology, and the abundance of some important pollen and spore types (Poaceae, Asteraceae, Isoetes). We employ a new chironomid training set developed for tropical South America (Matthews-Bird et al. 2016) to interpret shifts in chironomid assemblages. The sedimentary record from Yanacocha was first discussed by Beal et al. (2014), who reconstructed Hg deposition and measured metals, biogenic silica and loss-on-ignition through the Holocene. Additional downcore proxies are presented by Stroup et al. (this meeting). Yanacocha sits at 4910 m asl and less than 2 km from Quelccaya Ice Cap (QIC), but the lake's watershed has been topographically isolated from glacier meltwater since 12.3 ka. We compare our inferences from biological proxies with independent constraints on paleoclimate derived from published reconstructions of QIC fluctuations. Previous studies found that temperature was the primary driver of late Holocene fluctuations of QIC (e.g., Stroup et al. 2014), but records from the broader region indicate the Holocene also saw major changes in hydroclimate. Most modern precipitation at Yanacocha derives from the Amazon Basin to the east, and El Niño years are associated with drier conditions. Holocene sediments at Yanacocha likely thus record both changes in temperature and hydroclimate. Vegetation was sparse and no charcoal was preserved prior to 11.7 ka, whereas the early Holocene saw the highest overall pollen concentrations of the entire record and the onset of charcoal preservation. An increase in charcoal abundance, decrease in pollen concentrations, and shifts in vegetation and chironomid assemblages at Yanacocha suggest drier conditions from 9 to 3.5 ka, consistent with widespread regional evidence for early to middle

  20. From Protist to Proxy: Dinoflagellates as signal carriers for past climate and carbon cycling

    Science.gov (United States)

    Sluijs, A.; Reichart, G. J.; Hoins, M.; Waal, D. V. D.; Rost, B.; Roij, L. V.

    2016-12-01

    The (paleo)ecology of dinoflagellates and their organic dinocysts that preserve in sediments are often employed as tracers of past ocean conditions, such as temperature, productivity, ocean circulation, salinity, and sea ice, for the late Triassic to the Modern. Over the past decade, such reconstructions, which are based on empirical information as well as extensive studies of modern systems, have made dinocyst paleoecology a pivotal tool that is complementary to other microfossil groups and (in)organic geochemical techniques. Building on this work, we have carried out culturing experiments to quantify and physiologically underpin CO2-dependent carbon isotope fractionation of several species of dinoflagellates. This work indicates potential for a new CO2 proxy based on fossil dinoflagellate cysts. Moreover, we developed a laser ablation nano combustion gas chromatography isotope ratio mass spectrometry (LA-nC-GC-IRMS) setup capable of measuring δ13C of organic particles of only 40 nanograms of carbon, with accuracy and precision of at most 0.4‰. This allows for the analyses of single to a few dinocyst specimens, setting the stage for a whole new research field investigating variability within populations of dinocysts, but also of pollen and other small scale carbon particles in geology, biology and other research fields. We present the first dinocyst δ13C results of the new method from modern systems and in the paleo-domain, particularly related to marine carbon cycling and CO2.

  1. Differential proxy responses to late Allerød and early Younger Dryas climatic change recorded in varved sediments of the Trzechowskie palaeolake in Northern Poland

    Science.gov (United States)

    Słowiński, Michał; Zawiska, Izabela; Ott, Florian; Noryśkiewicz, Agnieszka M.; Plessen, Birgit; Apolinarska, Karina; Rzodkiewicz, Monika; Michczyńska, Danuta J.; Wulf, Sabine; Skubała, Piotr; Kordowski, Jarosław; Błaszkiewicz, Mirosław; Brauer, Achim

    2017-02-01

    High-resolution biological proxies (pollen, macrofossils, Cladocera and diatoms), geochemical data (μ-XRF element scans, TOC, C/N ratios, δ18Ocarb and δ13Corg values) and a robust chronology based on varve counting, AMS 14C dating and tephrochronology were applied to reconstruct lake system responses to rapid climatic and environmental changes of the Trzechowskie palaeolake (TRZ; Northern Poland) during the late Allerød - Younger Dryas (YD) transition. Palaeoecological and geochemical data at 5-15 years temporal resolution allowed tracing the dynamics of short-term shifts of the ecosystem triggered by abrupt climate change. The robust age control together with the high-resolution sampling allowed the detection of leads and lags between different proxies to the climate shift at the Allerød-Younger Dryas transition. Our results indicate (1) a water level decrease and an increase in wind activities during the late Allerød and the Allerød-YD transition, which caused intensified erosion in the catchment, (2) a two-decades delayed vegetation response in comparison to the lake depositional system. Comparison with the Lake Meerfelder Maar record revealed slightly different vegetation responses of the Trzechowskie palaeolake at the YD onset.

  2. Surface area changes of Himalayan ponds as a proxy of hydrological climate-driven fluctuations

    Science.gov (United States)

    Salerno, Franco; Thakuri, Sudeep; Guyennon, Nicolas; Viviano, Gaetano; Tartari, Gianni

    2016-04-01

    (glacial lake outburst floods). Whereas the lake surface areas variations of these lakes are strictly connected with the ablation processes and glacier velocities, variation related to unconnected glacial lakes are possibly influenced by only the resulting glacier melting. This difference with the other lake types makes unconnected glacial lakes potential indicators of changes of the main water balance components of high-elevated lake basins as: precipitation, glacier melting, and evapotranspiration. An evaluable opportunity for a fine-scale investigation on climate-driven fluctuations in lake surface area is particularly evident on the south slopes of Mt. Everest (Nepal), which is one of the most heavily glacierized parts of Himalaya, at same time, the region that is most characterized by glacial lakes in the overall Hindu-Kush-Himalaya range, and in which a twenty years series of temperature and precipitation has been recently reconstructed for high-elevations (5000 m a.s.l.). This contribution examines the surface area changes of unconnected glacial ponds, i.e., that are not directly connected with glaciers, on the south side of Mt. Everest in the last fifty years as part of an effort to evaluate if they can be considered potential indicators useful to detect how the climate is changed at high-elevations of the Himalayan range.

  3. Freshwater forcing on the greenhouse Arctic climate in the Late Cretaceous: Implications from proxies and model simulations

    Science.gov (United States)

    Radmacher, Wiesława; Niezgodzki, Igor; Setoyama, Eiichi; Tyszka, Jarosław; Mangerud, Gunn; Kaminski, Michael A.; Knorr, Gregor; Lohmann, Gerrit

    2017-04-01

    The Arctic experiences contrasting environmental changes under icehouse and greenhouse conditions. Unique tracers of greenhouse conditions recorded in Upper Cretaceous sediments provide basic mechanisms controlling this sensitive system. Based on dinoflagellate cysts and foraminifera from the Campanian and Maastrichtian in the Norwegian-Greenland seaway, Barents Sea, and Lomonosov Ridge, we show that this area experienced a progressive surface freshening during the Late Cretaceous. This is indicated by the organic-walled dinoflagellate cyst assemblage from the Norwegian-Greenland seaway and by shallow water benthic foraminifera from the Lomonosov Ridge, further suggesting brackish conditions in the surface water of the Arctic Basin. The freshening is explained by the influx of fresh water into a more isolated Arctic Basin via river discharge from the surrounding continents. In contrast to surface water proxies, benthic foraminiferal assemblages from the Norwegian-Greenland Seaway indicate higher deep water salinities during the Campanian. Multiple correspondence analyses as well as model simulations confirm the reconstructed sea surface freshening and suggest a salinity driven stratification within this seaway. The deep seaway can contribute to a long-term warm climate in the Arctic by a continuous exchange of the brackish and saline water masses between the Arctic Basin and the Western Tethys. During the Maastrichtian, a more restricted connection between these two regions could have reduced sea surface salinity in the Arctic Basin. Our Earth System Model simulations indicate a clear stratification pattern of the Arctic Basin with a strong temperature gradient of warm deep waters overlain by colder layers. The model demonstrates that such a water column structure could occur as an effect of the bidirectional water mass circulation. We suggest that such a 'heat pump system' is responsible for a long-term warming and stabilization of the Arctic climate during the

  4. Climate change scenarios and key climate indices in the Swiss Alpine region

    Science.gov (United States)

    Zubler, Elias; Croci-Maspoli, Mischa; Frei, Christoph; Liniger, Mark; Scherrer, Simon; Appenzeller, Christof

    2013-04-01

    For climate adaption and to support climate mitigation policy it is of outermost importance to demonstrate the consequences of climate change on a local level and in user oriented quantities. Here, a framework is presented to apply the Swiss national climate change scenarios CH2011 to climate indices with direct relevance to applications, such as tourism, transportation, agriculture and health. This framework provides results on a high spatial and temporal resolution and can also be applied in mountainous regions such as the Alps. Results are shown for some key indices, such as the number of summer days and tropical nights, growing season length, number of frost days, heating and cooling degree days, and the number of days with fresh snow. Particular focus is given to changes in the vertical distribution for the future periods 2020-2049, 2045-2074 and 2070-2099 relative to the reference period 1980-2009 for the A1B, A2 and RCP3PD scenario. The number of days with fresh snow is approximated using a combination of temperature and precipitation as proxies. Some findings for the latest scenario period are: (1) a doubling of the number of summer days by the end of the century under the business-as-usual scenario A2, (2) tropical nights appear above 1500 m asl, (3) the number of frost days may be reduced by more than 3 months at altitudes higher than 2500 m, (4) an overall reduction of heating degree days of about 30% by the end of the century, but on the other hand an increase in cooling degree days in warm seasons, and (5) the number of days with fresh snow tends to go towards zero at low altitudes. In winter, there is little change in snowfall above 2000 m asl (roughly -3 days) in all scenarios. The largest impact on snowfall is found along the Northern Alpine flank and the Jura (-10 days or roughly -50% in A1B for the winter season). It is also highlighted that the future projections for all indices strongly depend on the chosen scenario and on model uncertainty

  5. Incorporating Fundamentals of Climate Monitoring into Climate Indicators at the National Climatic Data Center

    Science.gov (United States)

    Arndt, D. S.

    2014-12-01

    In recent years, much attention has been dedicated to the development, testing and implementation of climate indicators. Several Federal agencies and academic groups have commissioned suites of indicators drawing upon and aggregating information available across the spectrum of climate data stewards and providers. As a long-time participant in the applied climatology discipline, NOAA's National Climatic Data Center (NCDC) has generated climate indicators for several decades. Traditionally, these indicators were developed for sectors with long-standing relationships with, and needs of, the applied climatology field. These have recently been adopted and adapted to meet the needs of sectors who have newfound sensitivities to climate and needs for climate data. Information and indices from NOAA's National Climatic Data Center have been prominent components of these indicator suites, and in some cases have been drafted in toto by these aggregators, often with improvements to the communicability and aesthetics of the indicators themselves. Across this history of supporting needs for indicators, NCDC climatologists developed a handful of practical approaches and philosophies that inform a successful climate monitoring product. This manuscript and presentation will demonstrate the utility this set of practical applications that translate raw data into useful information.

  6. Linking coral river runoff proxies with climate variability, hydrology and land-use in Madagascar catchments

    NARCIS (Netherlands)

    Maina, J.; de Moel, H.; Vermaat, J.E.; Bruggemann, J.H.; Guillaume, M.M.M.; Grove, C.A.; Madin, J.S.; Merz-Kraus, R.; Zinke, J.

    2012-01-01

    Understanding the linkages between coastal watersheds and adjacent coral reefs is expected to lead to better coral reef conservation strategies. Our study aims to examine the main predictors of environmental proxies recorded in near shore corals and therefore how linked near shore reefs are to the

  7. A proxy analysis of urban air quality hazards in Bergen, Norway under a changing climate.

    Science.gov (United States)

    Wolf, Tobias; Esau, Igor; Reuder, Joachim

    2014-05-01

    The urban air quality in Bergen, Norway is characterized by clean air throughout most of the year interrupted by short episodes of hazardous pollution levels especially in close proximity to major road-emission sources. These pollution episodes are linked to winter time anti-cyclonic weather conditions with persistent stable temperature stratification (inversions) in the Atmospheric Boundary Layer. Although the pollution episodes are local events, the high pollution episodes are linked to large-scale persistent blockings in the atmospheric circulation. Here we present an atmospheric circulation proxy for the pollution episodes based on the ECMWF ERA-Interim reanalysis. The proxy is based on local 3-hourly instantaneous wind-speeds and directions at the 1000 hPa pressure level, and 1-day running mean temperature deviations at 2 m above ground from the 1-day running mean temperatures averaged over the full ERA-Interim record length. We tuned the thresholds for each quantity to the occurrence of events with an hourly mean NO2 concentration > 150 μg/m3 at a high pollution reference station. A condition on cloud cover had only little effect, sea-level pressure was not applicable. High pollution episodes predicted during typical low traffic days (Sundays, Christmas, New Year) were removed. The final proxy had a detection rate of 82 %, a false alarm rate of 77 % and a correct null prediction rate of 96 %. The high false alarm rate was expected because of the relaxed thresholds chosen in order to include a large fraction of possible states of atmospheric circulation that lead to hazardous air quality. Additionally, the false alarm rate was high because no constraint on the persistence of adverse meteorological conditions was set and because of the high variability of traffic, not always leading to hazardous pollution levels, even if the atmospheric circulation would allow for it. The Scandinavian index, an often used proxy for the occurrence of atmospheric circulation

  8. Urban form indicators as proxy on the noise exposure of buildings

    OpenAIRE

    Silva, Lígia Torres; Oliveira, Marta Isabela Fernandes; Silva, José F.

    2014-01-01

    Available online 27 September 2013 The present paper aims to address the problems of the urban environment as an area of interaction between urban forms and urban noise. This interaction is intended to be monitored using urban indica-tors, by comparing the effects of noise propagation using models of urban forms. The model of noise pre-diction allowed developing noise studies in facades, resulting in noise levels in a calculation grid located in the building facades. The study will a...

  9. A 481-year chronology of oak earlywood vessels as an age-independent climatic proxy in NW Iberia

    Science.gov (United States)

    Souto-Herrero, Manuel; Rozas, Vicente; García-González, Ignacio

    2017-08-01

    The earlywood vessels of ring-porous trees can be analyzed dendrochronologically and used as a proxy for environmental information. However, most works deal with the analysis of contemporary climate-growth relationships and do not evaluate their long-term variation. We obtained a 481-year chronology of earlywood vessel size of oak (Quercus robur L.) in the northwestern Iberian Peninsula, investigated its behavior through time, and compared it to a chronology of younger trees developed at the same site. We expressed earlywood vessel size as the hydraulically-weighted diameter (DH) and discriminated between vessels in the first row (r1) and the rest of the vessels (nr1); radial increment was assessed from latewood width (LW). Climate-growth relationships were strong and nearly identical for both age classes. Spring temperature positively affected vessel size, but only for the first row, probably mediating the onset of cambial activity. The chronology of old trees showed an almost flat age trend, except for the first decades, and series were not affected by stand dynamics. In contrast, LW had a weak response to climate, probably because of the high impact of abrupt growth changes. There was a high negative correlation between DH and the winter North Atlantic Oscillation Index (NAO), which was unstable during the 20th century. To our knowledge, this is the longest chronology of earlywood vessel size obtained to date, and offers promising results, as this proxy is shown to be independent of age and forest disturbances, and was strongly correlated to climate across long time spans.

  10. Evaluating Carbon Isotope Signature of Bulk Organic Matter and Plant Wax Derived n-alkanes from Lacustrine Sediments as Climate Proxies along the Western Side of the Andes

    Science.gov (United States)

    Contreras, S.; Werne, J. P.; Araneda, A.; Conejero, C. A.

    2015-12-01

    Sedimentary carbon isotope values (δ13C) of bulk organic matter and long chain (C25 to C35) n-alkanes are among the most long-lived and widely utilized proxies of organic matter and vegetation source. The carbon distribution (e.g. average carbon chain length, ACL) and isotope signature from long chain n-alkanes had been intensively used on paleoclimate studies because they are less influenced by diagenesis, differential preservation of compound classes, and changes in the sources of organic matter than bulk δ13C values. Recently, studies of modern plant n-alkanes have challenged the use of carbon distribution and carbon isotope signature from sedimentary n-alkanes as reliable indicators of vegetation and climate change. The climate in central-south western South America (SA) is projected to become significantly warmer and drier over the next several decades to centuries in response to anthropogenically driven warming. Paleolimnological studies along western SA are critical to obtain more realistic and reliable regional reconstructions of past climate and environments, including vegetation and water budget variability. Here we discuss bulk δ13C, distribution and δ13C in long chain n-alkanes from a suite of ~40 lake surface sediment (core-top) samples spanning the transition from a Mediterranean climate with a patchwork of cultivated vegetation, pastureland, conifers in central Chile to a rainy temperate climate dominated by broadleaf deciduous and evergreen forest. Data are compared to the latitudinal and orographic climatic trends of the Andes based on the climatology (e.g. precipitation and temperature) of the locations of all lakes involved in this study, using monthly gridded reanalysis products of the Climate Forecast System Reanalysis (CFSR), based on the NCEP global forecast model and meteorological stations available in the region, from January 1979 to December 2010 with a 0.5° horizontal resolution.

  11. Wet and cold climate conditions recorded by coral geochemical proxies during the beginning of the first millennium CE in the northern South China Sea

    Science.gov (United States)

    Xiao, Hangfang; Deng, Wenfeng; Chen, Xuefei; Wei, Gangjian; Zeng, Ti; Zhao, Jian-xin

    2017-03-01

    The past two millennia include some distinct climate intervals, such as the Medieval Warm Period (MWP) and the Little Ice Age (LIA), which were caused by natural forcing factors, as well as the Current Warm Period (CWP) that has been linked to anthropogenic factors. Therefore, this period has been of great interest to climate change researchers. However, most studies are based on terrestrial proxy records, historical documentary data, and simulation results, and the ocean and the tropical record are very limited. The Eastern Han, Three Kingdoms, and Western Jin periods (25-316 CE) cover the beginning first millennium CE in China, and were characterized by a cold climate and frequent wars and regime changes. This study used paired Sr/Ca and δ18O series recovered from a fossil coral to reconstruct the sea surface water conditions during the late Eastern Han to Western Jin periods (167-309 CE) at Wenchang, eastern Hainan Island in the northern South China Sea (SCS), to investigate climate change at this time. The long-term sea surface temperature (SST) during the study interval was 25.1 °C, which is about 1.5 °C lower than that of the CWP (26.6 °C). Compared with the average value of 0.40‰ during the CWP, the long-term average seawater δ18O (-0.06‰) was more negative. These results indicate that the climate conditions during the study period were cold and wet and comparable with those of the LIA. This colder climate may have been associated with the weaker summer solar irradiance. The wet conditions were caused by the reduced northward shift of the intertropical convergence zone/monsoon rainbelt associated with the retreat of the East Asian summer monsoon. Interannual and interdecadal climate variability may also have contributed to the variations in SST and seawater δ18O recorded over the study period.

  12. Climate Change Indicators: Health and Society

    Science.gov (United States)

    ... some diseases. In addition, climate change could require adaptation on larger and faster scales than in the ... Ragweed Pollen Season Ecosystems Frequent Questions Main menu Environmental Topics Air Bed Bugs Chemicals and Toxics Environmental ...

  13. Climate Prediction Center (CPC) Palmer Drought and Crop Moisture Indices

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Climate Prediction Center (CPC) Palmer Drought Severity and Crop Moisture Indices are computed for the 344 U.S. Climate Divisions on a weekly basis based on a...

  14. Holocene Fluctuations of North Ice Cap, a Proxy for Climate Conditions along the Northwestern Margin of the Greenland Ice Sheet

    Science.gov (United States)

    Kelly, M. A.; Osterberg, E. C.; Lasher, G. E.; Farnsworth, L. B.; Howley, J. A.; Axford, Y.; Zimmerman, S. R. H.

    2015-12-01

    North Ice Cap (~76.9°N, 68°W, summit elevation 1322 m asl), a small, independent ice cap in northwestern Greenland, is located within ~25 km of the Greenland Ice Sheet margin and Harald Molkte Bræ outlet glacier. We present geochronological, geomorphic and sedimentological data constraining the Holocene extents of North Ice Cap and suggest that its past fluctuations can be used as a proxy for climate conditions along the northwestern margin of the Greenland Ice Sheet. Prior work by Goldthwait (1960) used glacial geomorphology and radiocarbon ages of subfossil plants emerging along shear planes in the ice cap margin to suggest that that North Ice Cap was not present during the early Holocene and nucleated in the middle to late Holocene time, with the onset of colder conditions. Subfossil plants emerging at shear planes in the North Ice Cap margin yield radiocarbon ages of ~4.8-5.9 cal kyr BP (Goldthwait, 1960) and ~AD 1000-1350 (950-600 cal yr BP), indicating times when the ice cap was smaller than at present. In situ subfossil plants exposed by recent ice cap retreat date to ~AD 1500-1840 (450-110 cal yr BP) and indicate small fluctuations of the ice cap margin. 10Be ages of an unweathered, lichen-free drift <100 m from the present North Ice Cap margin range from ~500 to 8000 yrs ago. We suggest that the drift was deposited during the last ~500 yrs and that the older 10Be ages are influenced by 10Be inherited from a prior period of exposure. We also infer ice cap fluctuations using geochemical data from a Holocene-long sediment core from Deltasø, a downstream lake that currently receives meltwater from North Ice Cap. The recent recession of the North Ice Cap margin influenced a catastrophic drainage of a large proglacial lake, Søndre Snesø, that our field team documented in August 2012. To our knowledge, this is the first significant lowering of Søndre Snesø in historical time.

  15. Compositing climate change vulnerability of a Mediterranean region using spatiotemporally dynamic proxies for ecological and socioeconomic impacts and stabilities.

    Science.gov (United States)

    Demirkesen, Ali Can; Evrendilek, Fatih

    2017-01-01

    The study presents a new methodology to quantify spatiotemporal dynamics of climate change vulnerability at a regional scale adopting a new conceptual model of vulnerability as a function of climate change impacts, ecological stability, and socioeconomic stability. Spatiotemporal trends of equally weighted proxy variables for the three vulnerability components were generated to develop a composite climate change vulnerability index (CCVI) for a Mediterranean region of Turkey combining Landsat time series data, digital elevation model (DEM)-derived data, ordinary kriging, and geographical information system. Climate change impact was based on spatiotemporal trends of August land surface temperature (LST) between 1987 and 2016. Ecological stability was based on DEM, slope, aspect, and spatiotemporal trends of normalized difference vegetation index (NDVI), while socioeconomic stability was quantified as a function of spatiotemporal trends of land cover, population density, per capita gross domestic product, and illiteracy. The zones ranked on the five classes of no-to-extreme vulnerability were identified where highly and moderately vulnerable lands covered 0.02% (12 km2) and 11.8% (6374 km2) of the study region, respectively, mostly occurring in the interior central part. The adoption of this composite CCVI approach is expected to lead to spatiotemporally dynamic policy recommendations towards sustainability and tailor preventive and mitigative measures to locally specific characteristics of coupled ecological-socioeconomic systems.

  16. The importance of being pillowed: using pillow lava as a paleo-climate proxie in glaciovolcanic settings

    Science.gov (United States)

    Edwards, Ben

    2010-05-01

    pressures, which are model dependent (e.g. Edwards et al., 2009). As demonstrated by many workers, close field and laboratory analysis of pillow lava has significant potential as a paleo-environmental proxie. Morphologies can be used to infer direct ice-contact. Volatile concentrations can constrain overlying ice/water thicknesses. The highest elevations of glaciovolcanic pillow lava constrain minimum ice thicknesses (e.g. Smellie 2000). Variations in vesicularity within pillow ridges can even be used to infer syn-eruption changes in confining pressures due to catastrophic water-drainage events (e.g. Hoskuldsson et al., 2006). Further refinements in our understanding of pillow lava formation will continue to improve the importance of being pillowed for using mafic glaciovolcanism as a climate proxie. References Edwards, BR, Skilling, IP, Cameron, B, Lloyd, A, Haynes, C, Hungerford, J (2009) Evolution of an englacial volcanic ridge: Pillow Ridge tindar, Mount Edziza volcanic complex, NCVP, British Columbia, Canada. Journal of Volcanology and Geothermal Research. DOI: 10.1016/j.jvolgeores.2008.11.015 Hoskuldsson, A., Sparks, R.S.J., Carroll, M.R. 2006. Constraints on the dynamics of subglacial basalt eruptions from geological and geochemical observations at Kverkfjoll, NE-Iceland. Bull. Volc. 68, 689-701. DOI 10.1007/s00445-005-0043-4 Skilling, IP (2009) Evolution of Hlöðufell Subglacial to Emergent Polygenetic Basaltic Volcano, SW Iceland. Journal of Volcanology and Geothermal Research. DOI: 10-1016/j/jvolgeores.2009.05.02 Smellie, J. L. 2000. Subglacial eruptions. In: Sigurdsson, H. (ed.) Encyclopedia of Volcanoes, Academic Press, San Diego, 403-418.

  17. Pedo-chemical climate proxies in Late Pleistocene Serbian-Ukranian loess sequences

    NARCIS (Netherlands)

    Bokhorst, M.P.; Beets, C.J.; Markovic, S.B.; Gerasimenko, N.P.; Matviishina, Z.N.; Frechen, M.

    2009-01-01

    The last glacial-interglacial loess-paleosol sequences of Serbia and Ukraine provide a good climate reconstruction potential for this part of Europe. Four loess sections distributed over an area with present-day moist to semi-arid climates were studied. In addition to traditional paleoclimate

  18. Phytoplankton assemblages and (bio)geochemical proxies indicate enhanced productivity and sea-ice decline in the Ross Sea during Marine Isotope sub-Stage 5e

    Science.gov (United States)

    Hartman, Julian; Sangiorgi, Francesca; Albertazzi, Sonia; Ángeles Bárcena, Mariá; Bijl, Peter; Giglio, Federico; Langone, Leonardo; Peterse, Francien; Tateo, Fabio; Trincardi, Fabio; Asioli, Alessandra

    2017-04-01

    Sea ice is an important component of the Antarctic cryosphere. It plays an important role in climate (e.g. albedo, gas exchange with the atmosphere), ocean circulation and primary productivity. Although sea ice has been increasing on average around Antarctica as a result of current global climate change, long-term model predictions expect sea ice to decline. To better understand the changes in sea-ice cover and its consequences on the oceanography, biology and geochemistry of the Southern Ocean during on-going and near-future warming it is important to study past periods of global warming, such as the Last Interglacial (LIG, 125-119 ka), also known as Marine Isotope sub-Stage 5e (MIS5e). During MIS5e global temperatures were on average 2°C warmer than present-day, the same temperature set as maximum global warming limit during the recent Paris Agreement (COP21). We investigated changes in sea-ice cover and environmental conditions by means of diatom, palynological, foraminifer and (bio)geochemical data in a sediment core (AS05-10) from the continental slope of the Drygalski Basin, Ross Sea (2377 mbsl) encompassing the MIS5e. The core was collected within the frame of the PNRA 2009/A2.01 project, an Italian project with a multidisciplinary approach, and covers approximately the last 350 kyr according to an age model based on diatom bioevents and cyclostratigraphy. The productivity proxies, e.g., excess barium, magnetic susceptibility and diatom abundances show a strong relation to the glacial-interglacial cycles. The rapid deglaciations preceding MIS5e and MIS7e are characterized by Ice Rafted Debris and the presence of reworked material. Subsequently, each interglacial is characterized by enhanced productivity related to a decrease in annual sea-ice cover. The beginning of each interglacial is also marked by changes in the fossil assemblages and organic geochemical proxies indicative of high nutrient conditions and water column stratification due to fresh water

  19. Was the Little Ice Age more or less El Niño-like than the Medieval Climate Anomaly? Evidence from hydrological and temperature proxy data

    Science.gov (United States)

    Henke, Lilo M. K.; Lambert, F. Hugo; Charman, Dan J.

    2017-03-01

    The El Niño-Southern Oscillation (ENSO) is the most important source of global climate variability on interannual timescales and has substantial environmental and socio-economic consequences. However, it is unclear how it interacts with large-scale climate states over longer (decadal to centennial) timescales. The instrumental ENSO record is too short for analysing long-term trends and variability and climate models are unable to accurately simulate past ENSO states. Proxy data are used to extend the record, but different proxy sources have produced dissimilar reconstructions of long-term ENSO-like climate change, with some evidence for a temperature-precipitation divergence in ENSO-like climate over the past millennium, in particular during the Medieval Climate Anomaly (MCA; AD ˜ 800-1300) and the Little Ice Age (LIA; AD ˜ 1400-1850). This throws into question the stability of the modern ENSO system and its links to the global climate, which has implications for future projections. Here we use a new statistical approach using weighting based on empirical orthogonal function (EOF) to create two new large-scale reconstructions of ENSO-like climate change derived independently from precipitation proxies and temperature proxies. The method is developed and validated using model-derived pseudo-proxy experiments that address the effects of proxy dating error, resolution, and noise to improve uncertainty estimations. We find no evidence that temperature and precipitation disagree over the ENSO-like state over the past millennium, but neither do they agree strongly. There is no statistically significant difference between the MCA and the LIA in either reconstruction. However, the temperature reconstruction suffers from a lack of high-quality proxy records located in ENSO-sensitive regions, which limits its ability to capture the large-scale ENSO signal. Further expansion of the palaeo-database and improvements to instrumental, satellite, and model representations of

  20. A Probabilistic Model of Chronological Errors in Layer-Counted Climate Proxies: Applications to Annually-Banded Coral Archives

    Science.gov (United States)

    Comboul, M.; Emile-Geay, J.; Evans, M. N.; Mirnateghi, N.; Cobb, K.; Thompson, D. M.

    2013-12-01

    The ability to precisely date climate proxies is central to the reconstruction of past climate variations. All climate proxies are affected by age uncertainties to some extent, and such age uncertainty is seldom quantified. This work proposes a probabilistic age model for proxies based on layer-counted chronologies, and explores its use for annually-banded coral archives. The model considers both errors due to missing rings and doubly-counted rings, which for simplicity we model as independent processes. The model can accommodate various assumptions about error rates and can be used to quantify how chronological uncertainties impact various diagnostics of variability. In one dimension, we find that time uncertainties primarily affect high-frequency signals (as expected) but also significantly bias the estimate of decadal signals. While tuning the coral data to an independent, tree-ring based chronology [Li et al., 2011] we show that correlations between the two records may be substantially improved by random age perturbations on the order of +/- 5 years per 100 bands in addition to adjustments within the error range of the U/Th dates. Using a synthetic pseudocoral network as testing ground, we quantify uncertainties in the estimation of spatiotemporal patterns of variability. Even for small error rates, the amplitude of multidecadal variability is systematically overestimated at the expense of interannual variability (ENSO, in this case), artificially flattening its spectrum at periods longer than 10 years. Finally, we present an approach to distinguish between chronologies and correct for age uncertainties within a network of time-uncertain records. The method is validated in idealized cases, where it consistently brings age-corrected chronologies closer to the true chronology. This optimization principle, however, is difficult to apply in practice due to the extremely high dimensionality of the space of plausible time perturbations. We end with a discussion of

  1. Utilizing Vegetation Indices as a Proxy to Characterize the Stability of a Railway Embankment in a Permafrost Region

    Directory of Open Access Journals (Sweden)

    Priscilla Addison

    2016-11-01

    Full Text Available Degrading permafrost conditions around the world are posing stability issues for infrastructure constructed on them. Railway lines have exceptionally low tolerances for differential settlements associated with permafrost degradation due to the potential for train derailments. Railway owners with tracks in permafrost regions therefore make it a priority to identify potential settlement locations so that proper maintenance or embankment stabilization measures can be applied to ensure smooth and safe operations. The extensive discontinuous permafrost zone along the Hudson Bay Railway (HBR in Northern Manitoba, Canada, has been experiencing accelerated deterioration, resulting in differential settlements that necessitate continuous annual maintenance to avoid slow orders and operational interruptions. This paper seeks to characterize the different permafrost degradation susceptibilities present at the study site. Track geometry exceptions were compared against remotely sensed vegetation indices to establish a relationship between track quality and vegetation density. This relationship was used as a proxy for subsurface condition verified by electrical resistivity tomography. The established relationship was then used to develop a three-level degradation susceptibility chart to indicate low, moderate and high susceptibility regions. The defined susceptibility regions can be used to better allocate the limited maintenance resources and also help inform potentially long-term stabilization measures for the severely affected sections.

  2. Evaluation of drought indices at interannual to climate change timescales: a case study over the Amazon and Mississippi river basins

    OpenAIRE

    E. Joetzjer; H. Douville; C. Delire; P. Ciais; B. Decharme; S. Tyteca

    2012-01-01

    The present study compares three meteorological drought indices (scPDSI, SPI and SPEI respectively) and their ability to account for the variations of annual mean river discharge on both interannual and climate change timescales. The Standardized Runoff Index (SRI) is used as a proxy of river discharge. The Mississippi and Amazon river basins provide two contrasted testbeds for this analysis. All meteorological drought indices are derived from monthly 2-meter temperature and/or precipitation,...

  3. Developing Present-day Proxy Cases Based on NARVAL Data for Investigating Low Level Cloud Responses to Future Climate Change.

    Science.gov (United States)

    Reilly, Stephanie

    2017-04-01

    The energy budget of the entire global climate is significantly influenced by the presence of boundary layer clouds. The main aim of the High Definition Clouds and Precipitation for Advancing Climate Prediction (HD(CP)2) project is to improve climate model predictions by means of process studies of clouds and precipitation. This study makes use of observed elevated moisture layers as a proxy of future changes in tropospheric humidity. The associated impact on radiative transfer triggers fast responses in boundary layer clouds, providing a framework for investigating this phenomenon. The investigation will be carried out using data gathered during the Next-generation Aircraft Remote-sensing for VALidation (NARVAL) South campaigns. Observational data will be combined with ECMWF reanalysis data to derive the large scale forcings for the Large Eddy Simulations (LES). Simulations will be generated for a range of elevated moisture layers, spanning a multi-dimensional phase space in depth, amplitude, elevation, and cloudiness. The NARVAL locations will function as anchor-points. The results of the large eddy simulations and the observations will be studied and compared in an attempt to determine how simulated boundary layer clouds react to changes in radiative transfer from the free troposphere. Preliminary LES results will be presented and discussed.

  4. Uncertainty assessment tool for climate change impact indicators

    Science.gov (United States)

    Otto, Juliane; Keup-Thiel, Elke; Jacob, Daniela; Rechid, Diana; Lückenkötter, Johannes; Juckes, Martin

    2015-04-01

    A major difficulty in the study of climate change impact indicators is dealing with the numerous sources of uncertainties of climate and non-climate data . Its assessment, however, is needed to communicate to users the degree of certainty of climate change impact indicators. This communication of uncertainty is an important component of the FP7 project "Climate Information Portal for Copernicus" (CLIPC). CLIPC is developing a portal to provide a central point of access for authoritative scientific information on climate change. In this project the Climate Service Center 2.0 is in charge of the development of a tool to assess the uncertainty of climate change impact indicators. The calculation of climate change impact indicators will include climate data from satellite and in-situ observations, climate models and re-analyses, and non-climate data. There is a lack of a systematic classification of uncertainties arising from the whole range of climate change impact indicators. We develop a framework that intends to clarify the potential sources of uncertainty of a given indicator and provides - if possible - solutions how to quantify the uncertainties. To structure the sources of uncertainties of climate change impact indicators, we first classify uncertainties along a 'cascade of uncertainty' (Reyer 2013). Our cascade consists of three levels which correspond to the CLIPC meta-classification of impact indicators: Tier-1 indicators are intended to give information on the climate system. Tier-2 indicators attempt to quantify the impacts of climate change on biophysical systems (i.e. flood risks). Tier-3 indicators primarily aim at providing information on the socio-economic systems affected by climate change. At each level, the potential sources of uncertainty of the input data sets and its processing will be discussed. Reference: Reyer, C. (2013): The cascade of uncertainty in modeling forest ecosystem responses to environmental change and the challenge of sustainable

  5. Impacts of Europe's changing climate- 2008 indicator-based assessment

    NARCIS (Netherlands)

    Swart, R.J.

    2008-01-01

    The report presents past and projected climate change and impacts in Europe by means of about 40 indicators and identifies sectors and regions most vulnerable with a high need for adaptation. The report covers the following indicator categories: atmosphere and climate, cryosphere, marine

  6. Nonlinear Shifts in Arctic Climate since the Holocene Thermal Maximum Recorded in a New High-Resolution Proxy Record from Otter Lake, South-Central Alaska

    Science.gov (United States)

    Bochicchio, C. J.; Yu, Z.

    2011-12-01

    Many paleoclimatic records show a gradual, near-linear cooling trend across the northern hemisphere since the Holocene Thermal Maximum, in response to an orbitally-driven gradual decline in summer insolation during the Holocene. Contrary to insolation trends, a few high-resolution records from high northern latitudes appear to indicate abrupt shifts in climate mean states. This suggests that Earth's climate system is capable of "step-like" transitions initiated when insolation thresholds are crossed and strong climatic feedbacks are triggered. In order to better understand the extent of possible nonlinear responses and forcing mechanisms, more high-resolution climate records are needed. In particular, records from Arctic regions are especially useful because Arctic climate feedbacks are stronger than in lower latitude regions and are well-documented. Here we present a multi-proxy record from a 4.8-m-long sediment core collected from Otter Lake, a small perched, precipitation- and groundwater-fed marl (carbonate-rich) lake (~300 m2 surface area, ~7 m depth), in south-central Alaska. The lake was formed more than 14,000 years ago after ice retreat. We combined a modern calibration study utilizing the relationship between lake depth and sediment composition along water-depth transects with down-core analysis of sedimentary proxies to reconstruct Holocene lake-level. We found three distinct periods of sedimentation: (1) the early Holocene: predominately carbonate-rich sediments (~70%) with low variability in sediment composition; (2) mid-Holocene: organic-rich sediments with low carbonate content (~20%) and very low variability; and (3) late Holocene: high average carbonate content (~50%) with the greatest variability in sediment composition (between 10% and 66% carbonate). We interpret the change in sediment composition to reflect lake-level change, with high carbonate content corresponding to shallow water, as observed from analysis of modern sediments. Therefore

  7. Characterisation of long-term climate change by dimension estimates of multivariate palaeoclimatic proxy data

    Directory of Open Access Journals (Sweden)

    R. Donner

    2006-01-01

    Full Text Available The problem of extracting climatically relevant information from multivariate geological records is tackled by characterising the eigenvalues of the temporarily varying correlation matrix. From these eigenvalues, a quantitative measure, the linear variance decay (LVD dimension density, is derived. The LVD dimension density is shown to serve as a suitable estimate of the fractal dimension density. Its performance is evaluated by testing it for (i systems with independent components and for (ii subsystems of spatially extended linearly correlated systems. The LVD dimension density is applied to characterise two geological records which contain information about climate variability during the Oligocene and Miocene. These records consist of (a abundances of different chemical trace elements and (b grain-size distributions obtained from sediment cores offshore the East Antarctic coast. The presented analysis provides evidence that the major climate change associated with the Oligocene-Miocene transition is reflected in significant changes of the LVD dimension density. This is interpreted as a change of the interrelationships between different trace elements in the sediment and to a change of the provenance area of the deposited sediment.

  8. Oxygen isotope ratios (18O/16O) of hemicellulose-derived sugar biomarkers in plants, soils and sediments as paleoclimate proxy II: Insight from a climate transect study

    Science.gov (United States)

    Tuthorn, Mario; Zech, Michael; Ruppenthal, Marc; Oelmann, Yvonne; Kahmen, Ansgar; Valle, Héctor Francisco del; Wilcke, Wolfgang; Glaser, Bruno

    2014-02-01

    The oxygen isotopic composition of precipitation (δ18Oprec) is well known to be a valuable (paleo-)climate proxy. Paleosols and sediments and hemicelluloses therein have the potential to serve as archives recording the isotopic composition of paleoprecipitation. In a companion paper (Zech et al., 2014) we investigated δ18Ohemicellulose values of plants grown under different climatic conditions in a climate chamber experiment. Here we present results of compound-specific δ18O analyses of arabinose, fucose and xylose extracted from modern topsoils (n = 56) along a large humid-arid climate transect in Argentina in order to answer the question whether hemicellulose biomarkers in soils reflect δ18Oprec. The results from the field replications indicate that the homogeneity of topsoils with regard to δ18Ohemicellulose is very high for most of the 20 sampling sites. Standard deviations for the field replications are 1.5‰, 2.2‰ and 1.7‰, for arabinose, fucose and xylose, respectively. Furthermore, all three hemicellulose biomarkers reveal systematic and similar trends along the climate gradient. However, the δ18Ohemicellulose values (mean of the three sugars) do not correlate positively with δ18Oprec (r = -0.54, p fucose and xylose do not simply reflect δ18Oprec but rather δ18Oleaf water. The correlation between measured δ18Ohemicellulose and modeled δ18Oleaf water is highly significant (r = 0.81, p < 0.001, n = 20). This finding can be attributed to the evaporative 18O enrichment of leaf water during transpiration. Model sensitivity tests using a Péclet-modified Craig-Gordon (PMCG) model corroborate that relative air humidity is a very rigorous climate parameter influencing δ18Oleaf water, whereas temperature is of minor importance. While oxygen exchange and degradation effects on δ18O values of hemicelluloses sugar biomarkers seem to be negligible (Zech et al., 2012), further effects that need to be considered when interpreting δ18Ohemicellulose

  9. Organic fertilization and sufficient nutrient status in prehistoric agriculture?--Indications from multi-proxy analyses of archaeological topsoil relicts.

    Directory of Open Access Journals (Sweden)

    Franziska Lauer

    Full Text Available Neolithic and Bronze Age topsoil relicts revealed enhanced extractable phosphorus (P and plant available inorganic P fractions, thus raising the question whether there was targeted soil amelioration in prehistoric times. This study aimed (i at assessing the overall nutrient status and the soil organic matter content of these arable topsoil relicts, and (ii at tracing ancient soil fertilizing practices by respective stable isotope and biomarker analyses. Prehistoric arable topsoils were preserved in archaeological pit fillings, whereas adjacent subsoils served as controls. One Early Weichselian humic zone represented the soil status before the introduction of agriculture. Recent topsoils served as an additional reference. The applied multi-proxy approach comprised total P and micronutrient contents, stable N isotope ratios, amino acid, steroid, and black carbon analyses as well as soil color measurements. Total contents of P and selected micronutrients (I, Cu, Mn, Mo, Se, Zn of the arable soil relicts were above the limits for which nutrient deficiencies could be assumed. All pit fillings exhibited elevated δ15N values close to those of recent topsoils (δ15N>6 to 7‰, giving first hints for prehistoric organic N-input. Ancient legume cultivation as a potential source for N input could not be verified by means of amino acid analysis. In contrast, bile acids as markers for faecal input exhibited larger concentrations in the pit fillings compared with the reference and control soils indicating faeces (i.e. manure input to Neolithic arable topsoils. Also black carbon contents were elevated, amounting up to 38% of soil organic carbon, therewith explaining the dark soil color in the pit fillings and pointing to inputs of burned biomass. The combination of different geochemical analyses revealed a sufficient nutrient status of prehistoric arable soils, as well as signs of amelioration (inputs of organic material like charcoal and faeces

  10. Organic fertilization and sufficient nutrient status in prehistoric agriculture?--Indications from multi-proxy analyses of archaeological topsoil relicts.

    Science.gov (United States)

    Lauer, Franziska; Prost, Katharina; Gerlach, Renate; Pätzold, Stefan; Wolf, Mareike; Urmersbach, Sarah; Lehndorff, Eva; Eckmeier, Eileen; Amelung, Wulf

    2014-01-01

    Neolithic and Bronze Age topsoil relicts revealed enhanced extractable phosphorus (P) and plant available inorganic P fractions, thus raising the question whether there was targeted soil amelioration in prehistoric times. This study aimed (i) at assessing the overall nutrient status and the soil organic matter content of these arable topsoil relicts, and (ii) at tracing ancient soil fertilizing practices by respective stable isotope and biomarker analyses. Prehistoric arable topsoils were preserved in archaeological pit fillings, whereas adjacent subsoils served as controls. One Early Weichselian humic zone represented the soil status before the introduction of agriculture. Recent topsoils served as an additional reference. The applied multi-proxy approach comprised total P and micronutrient contents, stable N isotope ratios, amino acid, steroid, and black carbon analyses as well as soil color measurements. Total contents of P and selected micronutrients (I, Cu, Mn, Mo, Se, Zn) of the arable soil relicts were above the limits for which nutrient deficiencies could be assumed. All pit fillings exhibited elevated δ15N values close to those of recent topsoils (δ15N>6 to 7‰), giving first hints for prehistoric organic N-input. Ancient legume cultivation as a potential source for N input could not be verified by means of amino acid analysis. In contrast, bile acids as markers for faecal input exhibited larger concentrations in the pit fillings compared with the reference and control soils indicating faeces (i.e. manure) input to Neolithic arable topsoils. Also black carbon contents were elevated, amounting up to 38% of soil organic carbon, therewith explaining the dark soil color in the pit fillings and pointing to inputs of burned biomass. The combination of different geochemical analyses revealed a sufficient nutrient status of prehistoric arable soils, as well as signs of amelioration (inputs of organic material like charcoal and faeces-containing manure).

  11. A forward looking, actor based, indicator for climate gas emissions

    Energy Technology Data Exchange (ETDEWEB)

    Ericson, Torgeir; Randers, Joergen

    2011-04-15

    The most commonly used Norwegian indicator for climate change displays historical emissions and compare with Norway's Kyoto target. This indicator says little about future emissions, about the ongoing Norwegian effort to reduce climate gas emissions, or about its effect on sustainability. In this paper we propose an indicator that improves on these weaknesses. We present a forward looking climate indicator that in addition to historic data includes business as usual scenarios, different proposals for future domestic emissions, and national or international commitments and agreements. This indicator presents - in one graph - a broad diversity of views on how the climate challenge should be handled from now and into the future. This indicator-graph may contribute to a more transparent discussion of available policy options. (Author)

  12. Communicating global climate change using simple indices: an update

    Energy Technology Data Exchange (ETDEWEB)

    Drost, Frank; Karoly, David [University of Melbourne, School of Earth Sciences, Melbourne, VIC (Australia); Braganza, Karl [National Climate Centre, Bureau of Meteorology, Melbourne, VIC (Australia)

    2012-08-15

    Previous studies have shown that there are several indices of global-scale temperature variations, in addition to global-mean surface air temperature, that are useful for distinguishing natural internal climate variations from anthropogenic climate change. Appropriately defined, such indices have the ability to capture spatio-temporal information in a similar manner to optimal fingerprints of climate change. These indices include the contrast between the average temperatures over land and over oceans, the Northern Hemisphere meridional temperature gradient, the temperature contrast between the Northern and Southern Hemisphere and the magnitude of the annual cycle of average temperatures over land. They contain information independent of the global-mean temperature for internal climate variations at decadal time scales and represent different aspects of the climate system, yet they show common responses to anthropogenic climate change. In addition, the ratio of average temperature changes over land to those over the oceans should be nearly constant for transient climate change. Hence, supplementing analysis of global-mean surface temperature with analyses of these indices can strengthen results of attribution studies of causes of observed climate variations. In this study, we extend the previous work by including the last 10 years of observational data and the CMIP3 climate model simulations analysed for the IPCC AR4. We show that observed changes in these indices over the last 10 years provide increased evidence of an anthropogenic influence on climate. We also show the usefulness of these indices for evaluating the performance of climate models in simulating large-scale variability of surface temperature. (orig.)

  13. National Climate Assessment Indicators: Background, Development, & Examples

    Energy Technology Data Exchange (ETDEWEB)

    Janetos, Anthony C.; Chen, Robert; Arndt, Deke; Kenney, Melissa A.; Abbasi, Daniel; Armstrong, Tom; Bartuska, Ann; Blair, Maria; Buizer, Jim; Dietz, Tom; Easterling, Dave; Kaye, Jack; Kolian, Michael; McGeehin, Michael; O' Connor, Robert; Pulwarty, Roger; Running, Steve; Schmalensee, Dick; Webb, Robert; Weltzin, Jake; Baptista, Sandra; Enquist, Carolyn A.; Janetos, Anthony C.; Chen, Robert; Arndt, Deke; Hatfield, Jerry; Hayes, Mark L.; Jones, K. Burce; McNutt, Chad; Meier, Wayne R.; Schwartz, Mark D.; Svoboda, Mark

    2012-02-28

    Indicators are usually thought of as measurements or calculations that represent important features of the status, trend, or performance of a system of interest (e.g. the economy, agriculture, air quality). They are often used for the most practical of reasons – one cannot measure everything important about systems of interest, so there is a practical need to identify major features that can be reported periodically and used to guide both research and decisions (NRC 2000).

  14. Climate risk management based on climate modes and indices - the potential in Australian agribusinesses

    OpenAIRE

    Best, Peter; Stone, Roger; Sosenko, Olena

    2007-01-01

    Global and hemispheric climate indicators have proved useful in many countries for characterising intra- and inter-annual variability in climate processes, agricultural output and biomass production. They also form the basis of successful seasonal climate and production prediction systems for the probability distributions of allied parameters such as rainfall or crop yield. Climate risk management via derivative, insurance or bond instruments has only recently incorporated non-local climate p...

  15. Climatic changes in the Antarctic Eocene: - palaeontological, mineralogical and geochemical fossil proxies from bryozoans

    Science.gov (United States)

    Hara, Urszula

    2017-04-01

    (Bartonian in age). Contrary to that, the bryozoan fauna recognized in the upper part of the LMF (Telm7) is composed of the impoverished biota of the scarse lepraliomorphs, poorly preserved cyclostome of Iridmonoidea and Reticrescis, which are abundantly accompanied by the gadiform fish remains, penguin bones and whales. A sharp decrease in the bryozoan diversity near the contact between the Telm5 and Telm6 was connected with the climatic cooling event, which culminated at the time of deposition of the upper part of the LMF. The skeletal mineralogy along with the geochemical stable isotope studies of the bryozoans (Seymour Island, Antarctic Peninsula) help to elucidate the environmental and climatic changes connected with the Early Eocene Climatic Optimum (EECO), Middle Eocene Climatic Optimum (MECO) as well as the EOT in the stratigraphical profile of the La Meseta Formation. References Hara U. 2015. Bryozoan internal moulds from the La Meseta Formation (Eocene) of Seymour Island, Antarctic Peninsula. Polish Polar Research, vol. 36, 25-49. Hara U., Mors T., Hagstrom J. and Reguero M.A. 2017. Eocene bryozoans assemblages from the La Meseta Formation of Seymour Island, Antarctica (in review).

  16. Validating a Biogeochemical Watershed Disturbance and Climate Change Proxy: Tampa Bay. FL

    Science.gov (United States)

    Schwing, P. T.; Martinez, E.; Pyrtle, A. J.; Haynes, S.

    2007-12-01

    The Tampa Bay estuary and watershed have been impacted in the past century by residential and industrial development activities that have resulted in pollutant release via runoff and wastewater discharges. Mangrove forest loss, mining activities, accidental spills and nutrient loading have also decreased water quality in this aquatic environment. The primary goal of this project is to provide historical water quality and climate information by determining biogeochemical properties of oyster shells and sediments collected from various locations throughout the Tampa Bay region including ancient Native American shell mounds. Biogeochemical properties of shells collected from these middens will provide insight regarding historical water quality of Tampa Bay. It is expected that a pristine, pre-Columbian baseline may be revealed from the midden shells, and changes in the biogeochemical record may be demonstrated over the recent past from the industrial age to modern day on a seasonal and yearly scale. In order to achieve the goal of this project, midden shells and sediments will be collected and compared from three stations in Tampa Bay that range from undisturbed to severely impacted; Emerson Point, Weedon Island, and Bayboro Harbor, respectively. Water and sediment samples have also been examined to provide additional information regarding radiogeochemical properties of the three study sites. Sediments will be dated using gamma spectrometry techniques (U/Th series). Standard ICP-OES methods are being utilized to determine concentrations of trace, minor and major elements in the oyster and sediment samples. This project is part of a larger on-going investigation. If successful, this investigation will ultimately yield a high-resolution tool for establishing the history of terrestrial land use and climate change.

  17. Late Holocene climate change recorded in proxy records from a Bransfield Basin sediment core, Antarctic Peninsula

    Directory of Open Access Journals (Sweden)

    Alex Barnard

    2014-06-01

    Full Text Available The glacimarine environment of the Antarctic Peninsula region is one of the fastest warming places on Earth today, but details of changes in the recent past remain unknown. Large distances and widespread variability separate late Holocene palaeoclimate reconstructions in this region. This study focuses on a marine sediment core collected from ca. 2000 m below sea level in the Central Bransfield Strait that serves as a key for understanding changes in this region. The core yielded a high sedimentation rate and therefore provides an exceptional high-resolution sedimentary record composed of hemipelagic sediment, with some turbidites. An age model has been created using radiocarbon dates that span the Late Holocene: 3560 cal yr BP to present. This chronostratigraphic framework was used to establish five units, which are grouped into two super-units: a lower super-unit (3560–1600 cal yr BP and an upper super-unit (1600 cal yr BP–present, based on facies descriptions, laser particle size analysis, x-ray analysis, multi-sensor core logger data, weight percentages and isotopic values of total organic carbon and nitrogen. We interpret the signal contained within the upper super-unit as an increase in surface water irradiance and/or shortening of the sea-ice season and the five units are broadly synchronous with climatic intervals across the Antarctic Peninsula region. While the general trends of regional climatic periods are represented in the Bransfield Basin core we have examined, each additional record that is obtained adds variability to the known history of the Antarctic Peninsula, rather than clarifying specific trends.

  18. Geographic variation in climate as a proxy for climate change: Forecasting evolutionary trajectories from species differentiation and genetic correlations.

    Science.gov (United States)

    Schneider, Heather E; Mazer, Susan J

    2016-01-01

    Climate change models for California predict a warmer, drier future, potentially resulting in shorter growing seasons. If phenotypic differences between closely related species currently distributed across a moisture and temperature gradient represent adaptations to their abiotic environment, then as conditions become warmer and drier, populations presently adapted to cooler and wetter conditions may evolve to become more similar to those adapted to warmer and drier conditions. Two sister species, Clarkia unguiculata and C. exilis, are distributed across a moisture and temperature gradient in the southern Sierra Nevada, providing an opportunity to predict how this process may occur. In a greenhouse experiment using wild-collected seeds from 11 populations in the southern Sierra Nevada, we examined relationships among elevation, climatic conditions, and population means for each trait, then evaluated bivariate relationships among maternal family means, using raw values and controlling for population and seed mass effects on phenotype. Clarkia exilis occupied warmer, drier conditions, typically at lower elevations, than C. unguiculata did and flowered earlier and faster, producing smaller flowers with lower herkogamy. In C. unguiculata, petal area, herkogamy, and the rate of flower production were positively correlated with days to first flower. If selection favors earlier flowering, smaller petals, or faster flower production in C. unguiculata, then the genetic correlations among these traits should reinforce their joint evolution. Moreover, the correlations between these traits and herkogamy may promote the evolution of self-fertilization as an indirect response to selection, a previously unrecognized potential outcome of climate change. © 2016 Botanical Society of America.

  19. Downscaling of climate change scenarios and key climate indices in the Swiss Alpine region

    Science.gov (United States)

    Zubler, Elias; Croci-Maspoli, Mischa; Fischer, Andreas; Frei, Christoph; Scherrer, Simon; Appenzeller, Christof

    2013-04-01

    Probabilistic climate change scenarios for Switzerland have been developed in the framework of the national Swiss CH2011 initiative. However, no information could be provided for the mountainous regions of the Alps. Here, we present an extension of the CH2011 scenarios for this higher altitudes and complex topography. Additionally, a methodology is introduced to provide such scenarios on a high-resolution grid and on a daily basis. Results are shown for some key climate indices, such as the number of summer days and tropical nights, growing season length, number of frost days, heating and cooling degree days, and the number of days with fresh snow. Particular focus is given to changes in the vertical distribution for the future periods 2020-2049, 2045-2074 and 2070-2099 relative to the reference period 1980-2009 for the A1B, A2 and RCP3PD scenario. The number of days with fresh snow is approximated using a combination of temperature and precipitation as proxies. Some findings for the latest scenario period are: (1) a doubling of the number of summer days by the end of the century under the business-as-usual scenario A2, (2) tropical nights appear above 1500 m asl, (3) the number of frost days may be reduced by more than 3 months at altitudes higher than 2500 m, (4) an overall reduction of heating degree days of about 30% by the end of the century, but on the other hand an increase in cooling degree days in warm seasons, and (5) the number of days with fresh snow tends to go towards zero at low altitudes. In winter, there is little change in snowfall above 2000 m asl (roughly -3 days) in all scenarios. The largest impact on snowfall is found along the Northern Alpine flank and the Jura (-10 days or roughly -50% in A1B for the winter season). It is also highlighted that the future projections for all indices strongly depend on the chosen scenario and on model uncertainty.

  20. Past climate variability between 97 and 7 ka reconstructed from a multi proxy speleothem record from Western Cuba

    Science.gov (United States)

    Winterhalder, Sophie; Scholz, Denis; Mangini, Augusto; Spötl, Christoph; Jochum, Klaus Peter; Pajón, Jesús M.

    2016-04-01

    The tropical hydrological cycle plays a key role in regulating global climate, mainly through the export of heat and moisture to higher latitudes, and is highly sensitive to climate change, for instance due to changes in the position of the Intertropical Convergence Zone (ITCZ). Previous work on Caribbean stalagmites suggests a strong connection of precipitation variability to North Atlantic (NA) sea surface temperatures on multidecadal to millenial timescales (Fensterer et al., 2012; Fensterer et al., 2013; Winter et al., 2011). Cold phases in the NA potentially lead to a southward shift of the ITCZ and thus drier conditions in Cuba. On orbital timescales, Cuban stalagmites suggest a relation of speleothem δ18O values with the δ18O value of Caribbean surface waters (Fensterer et al., 2013). Here we present an expansion of the Cuban speleothem record covering the whole last glacial period from the end of MIS5c (97 ka BP) until 7 ka with hiatuses between 93-80 ka, 37-35 ka and 13-10 ka. Stalagmite Cuba medio (CM) has been precisely dated with 60 230Th/U-ages, mainly performed by the MC-ICPMS technique. The δ18O and δ13C records are completed by a continuous, high resolution LA-ICPMS trace element profile. These data allow for the first time to establish a multi-proxy climate reconstruction for the North Western Caribbean at decadal to centennial resolution for this period. The long-term variability of the δ18O values probably reflects rainfall amount in Cuba. The response to some Dansgaard/Oeschger and Heinrich stadials confirms the previously observed correlation between Caribbean and NA climate variability. However, this connection is not clearly imprinted throughout the record. Furthermore, trace elements, such as Mg, do not proof without ambiguity drier conditions in Cuba during NA cold events, such as the Heinrich stadials. This suggests that climate variability in Cuba was more complex during the last 100ka, and that the NA was not the only driving factor

  1. Here be web proxies

    DEFF Research Database (Denmark)

    Weaver, Nicholas; Kreibich, Christian; Dam, Martin

    2014-01-01

    HTTP proxies serve numerous roles, from performance enhancement to access control to network censorship, but often operate stealthily without explicitly indicating their presence to the communicating endpoints. In this paper we present an analysis of the evidence of proxying manifest in executions...... of the ICSI Netalyzr spanning 646,000 distinct IP addresses ("clients"). To identify proxies we employ a range of detectors at the transport and application layer, and report in detail on the extent to which they allow us to fingerprint and map proxies to their likely intended uses. We also analyze 17...

  2. A Kantian approach to a sustainable development indicator for climate

    Energy Technology Data Exchange (ETDEWEB)

    Greaker, Mads; Stoknes, Per Espen; Alfsen, Knut H.; Ericson, Torgeir

    2012-11-01

    How can the informed citizen know if the government is implementing a good-enough climate change policy? Most developed democracies have their own set of indicators for sustainable development, including indicators for climate change. These include yearly national emissions of greenhouse gasses (GHGs), global concentration of GHGs in the atmosphere and time series for global temperatures. However, without some kind of benchmark neither national emissions of GHGs nor global concentration of GHGs or temperatures, make it possible for the general public to evaluate the current climate policy of a nation state. In this paper we propose a benchmark for national climate policy based on a remaining Co2 budget allocated by egalitarian principles. Moreover, based on Kantian ethics we argue that this benchmark should be used as a sustainable development indicator for climate change. One way of interpreting Kantian ethics is to demand that each nation state should act as if a just global treaty on climate change were in place. We discuss possible important elements in a global treaty, and show how the different elements can be integrated in a forward-looking indicator of national climate policy.(auth)

  3. Impact of late glacial climate variations on stratification and trophic state of the meromictic lake Längsee (Austria: validation of a conceptual model by multi proxy studies

    Directory of Open Access Journals (Sweden)

    Jens MÜLLER

    2002-02-01

    Full Text Available Selected pigments, diatoms and diatom-inferred phosphorus (Di-TP concentrations of a late glacial sediment core section of the meromictic Längsee, Austria, were compared with tephra- and varve-dated pollen stratigraphic and geochemical results. A conceptual model was adopted for Längsee and evaluated using multi proxy data. During the unforested late Pleniglacial, a holomictic lake stage with low primary productivity prevailed. Subsequent to the Lateglacial Betula expansion, at about 14,300 cal. y BP, okenone and isorenieratene, pigments from purple and green sulphur bacteria, indicate the onset of anoxic conditions in the hypolimnion. The formation of laminae coincides with this anoxic, meromictic period with high, though fluctuating, amounts of okenone that persisted throughout the Lateglacial interstadial. The occurrence of unlaminated sediment sections of allochthonous origin, and concurrent low concentrations of okenone, were related to cool and wet climate fluctuations during this period, probably coupled with a complete mixing of the water column. Two of these oscillations of the Lateglacial interstadial have been correlated tentatively with the Aegelsee and Gerzensee oscillations in the Alps. The latter climate fluctuation divides a period of enhanced anoxia and primary productivity, correlated with the Alleröd chronozone. Continental climate conditions were assumed to be the main driving forces for meromictic stability during Alleröd times. In addition, calcite dissolution due to severe hypolimnetic anoxia, appear to have supported meromictic stability. Increased pigment concentrations, which are in contrast to low diatom-inferred total phosphorus (Di- TP, indicate the formation of a productive metalimnion during this period, probably due to a clear-water phase (low catchment erosion, increased temperatures, and a steep gradient between the phosphorus enriched hypolimnion and the oligotrophic epilimnion. Meltwater impacts from an

  4. Utilizing the social media data to validate 'climate change' indices

    Science.gov (United States)

    Molodtsova, T.; Kirilenko, A.; Stepchenkova, S.

    2013-12-01

    Reporting the observed and modeled changes in climate to public requires the measures understandable by the general audience. E.g., the NASA GISS Common Sense Climate Index (Hansen et al., 1998) reports the change in climate based on six practically observable parameters such as the air temperature exceeding the norm by one standard deviation. The utility of the constructed indices for reporting climate change depends, however, on an assumption that the selected parameters are felt and connected with the changing climate by a non-expert, which needs to be validated. Dynamic discussion of climate change issues in social media may provide data for this validation. We connected the intensity of public discussion of climate change in social networks with regional weather variations for the territory of the USA. We collected the entire 2012 population of Twitter microblogging activity on climate change topic, accumulating over 1.8 million separate records (tweets) globally. We identified the geographic location of the tweets and associated the daily and weekly intensity of twitting with the following parameters of weather for these locations: temperature anomalies, 'hot' temperature anomalies, 'cold' temperature anomalies, heavy rain/snow events. To account for non-weather related events we included the articles on climate change from the 'prestige press', a collection of major newspapers. We found that the regional changes in parameters of weather significantly affect the number of tweets published on climate change. This effect, however, is short-lived and varies throughout the country. We found that in different locations different weather parameters had the most significant effect on climate change microblogging activity. Overall 'hot' temperature anomalies had significant influence on climate change twitting intensity.

  5. Indicators and metrics for the assessment of climate engineering

    Science.gov (United States)

    Oschlies, A.; Held, H.; Keller, D.; Keller, K.; Mengis, N.; Quaas, M.; Rickels, W.; Schmidt, H.

    2017-01-01

    Selecting appropriate indicators is essential to aggregate the information provided by climate model outputs into a manageable set of relevant metrics on which assessments of climate engineering (CE) can be based. From all the variables potentially available from climate models, indicators need to be selected that are able to inform scientists and society on the development of the Earth system under CE, as well as on possible impacts and side effects of various ways of deploying CE or not. However, the indicators used so far have been largely identical to those used in climate change assessments and do not visibly reflect the fact that indicators for assessing CE (and thus the metrics composed of these indicators) may be different from those used to assess global warming. Until now, there has been little dedicated effort to identifying specific indicators and metrics for assessing CE. We here propose that such an effort should be facilitated by a more decision-oriented approach and an iterative procedure in close interaction between academia, decision makers, and stakeholders. Specifically, synergies and trade-offs between social objectives reflected by individual indicators, as well as decision-relevant uncertainties should be considered in the development of metrics, so that society can take informed decisions about climate policy measures under the impression of the options available, their likely effects and side effects, and the quality of the underlying knowledge base.

  6. National, ready-to-use climate indicators calculation and dissemination

    Science.gov (United States)

    Desiato, F.; Fioravanti, G.; Fraschetti, P.; Perconti, W.; Toreti, A.

    2010-09-01

    In Italy, meteorological data necessary and useful for climate studies are collected, processed and archived by a wide range of national and regional institutions. As a result, the density of the stations, the length and frequency of the observations, the quality control procedures and the database structure vary from one dataset to the other. In order to maximize the use of those data for climate knowledge and climate change assessments, a computerized system for the collection, quality control, calculation, regular update and rapid dissemination of climate indicators (denominated SCIA) was developed. Along with the pieces of information provided by complete metadata, climate indicators consist of statistics (mean, extremes, date of occurrence, standard deviation) over ten-days, monthly and yearly time periods of meteorological variables, including temperature, precipitation, humidity, wind, water balance, evapotranspitaton, degree-days, cloud cover, sea level pressure, solar radiation. In addition, normal values over thirty-year reference climatological periods and yearly anomalies are calculated and made available. All climate indicators, as well as their time series at a single location or spatial distribution at a selected time, are available through a dedicated web site (www.scia.sinanet.apat.it). In addition, secondary products like high resolution temperature maps obtained by kriging spatial interpolation, are made available. Over the last three years, about 40000 visitors accessed to the SCIA web site, with an average of 45 visitors per day. Most frequent visitors belong to categories like universities and research institutes; private companies and general public are present as well. Apart from research purposes, climate indicators disseminated through SCIA may be used in several socio-economic sectors like energy consumption, water management, agriculture, tourism and health. With regards to our activity, we base on these indicators for the estimation of

  7. Chapter 7 - Climate effects on lichen indicators for nitrogen

    Science.gov (United States)

    Sarah Jovan

    2014-01-01

    The Lichen Communities Indicator is a sensitive indicator of forest health changes caused by air quality, climate change, and other stressors. To date, more than 8,000 epiphytic lichen surveys have been collected across the Nation by the Forest Inventory Analysis (FIA) and Forest Health Monitoring (FHM) Programs and their partners (table 7.1; Phelan and others 2012)....

  8. Precipitation Indices as a Tool for Climate-Resilient Development in the Peruvian Andes

    Science.gov (United States)

    Chisolm, R. E.; McKinney, D. C.

    2016-12-01

    The local people living in the mountains of the Ancash Department in Peru have noticed changes in their water supply as climate change has altered precipitation patterns. They are seeking adaptation solutions to help guarantee the reliability of their water supply, but there has been very little analysis of historical data to evaluate and justify these adaptation solutions. In addition, Peru's Ministry of Economy and Finance now requires that climate change be part of the vulnerability assessment for all public investment project proposals, but there are currently no tools or methods of data analysis for including climate change in vulnerability assessments. Compounding the difficulties of considering climate change in the sustainability of development projects is the scarcity of climate data in the region and the difficulty of accessing existing data. To counteract this problem, the Peruvian government recommends using local people's perceptions of change as a proxy for gauged climate data. This work focuses on precipitation data analysis in the mountains of Ancash, Peru. The objectives of this analysis were to determine the accuracy of the local population's perceptions of climate change and to investigate how changes in precipitation patterns might impact public investment projects. The precipitation data analysis was compared to a local study of perceptions of change to determine whether or not these perceptions might be used in lieu of gauged climate data. It appears that people's perceptions of precipitation trends do not accurately reflect the trends observed in the gauged data. The methods of analysis were designed so that the results may be useful for public investment projects with a particular emphasis on agricultural projects. The data were analyzed for trends, seasonal patterns and variability. Dry spells were examined, and the results indicate that droughts during the rainy season have become more frequent and of longer duration. This could have

  9. Predicting Dengue Fever Outbreaks in French Guiana Using Climate Indicators

    Science.gov (United States)

    Adde, Antoine; Roucou, Pascal; Mangeas, Morgan; Ardillon, Vanessa; Desenclos, Jean-Claude; Rousset, Dominique; Girod, Romain; Briolant, Sébastien; Quenel, Philippe; Flamand, Claude

    2016-01-01

    Background Dengue fever epidemic dynamics are driven by complex interactions between hosts, vectors and viruses. Associations between climate and dengue have been studied around the world, but the results have shown that the impact of the climate can vary widely from one study site to another. In French Guiana, climate-based models are not available to assist in developing an early warning system. This study aims to evaluate the potential of using oceanic and atmospheric conditions to help predict dengue fever outbreaks in French Guiana. Methodology/Principal Findings Lagged correlations and composite analyses were performed to identify the climatic conditions that characterized a typical epidemic year and to define the best indices for predicting dengue fever outbreaks during the period 1991–2013. A logistic regression was then performed to build a forecast model. We demonstrate that a model based on summer Equatorial Pacific Ocean sea surface temperatures and Azores High sea-level pressure had predictive value and was able to predict 80% of the outbreaks while incorrectly predicting only 15% of the non-epidemic years. Predictions for 2014–2015 were consistent with the observed non-epidemic conditions, and an outbreak in early 2016 was predicted. Conclusions/Significance These findings indicate that outbreak resurgence can be modeled using a simple combination of climate indicators. This might be useful for anticipating public health actions to mitigate the effects of major outbreaks, particularly in areas where resources are limited and medical infrastructures are generally insufficient. PMID:27128312

  10. Non-destructive foraminiferal paleoclimatic proxies: A brief insight

    Digital Repository Service at National Institute of Oceanography (India)

    Saraswat, R.

    Non-Destructive Foraminiferal Paleoclimatic Proxies: A Brief Insight The knowledge of past climate can help us to understand imminent climatic changes. Oceans are the vast archives of past climate. Various indirect techniques termed as proxies...

  11. The suitability of Mytilus edulis as proxy archive and its response to ocean acidification

    OpenAIRE

    Heinemann, Agnes

    2011-01-01

    Past climate changes can be used as indicators of future scenarios, however past climatic changes can not be directly observed. Therefore, the reconstruction of past abiotic conditions can approximated using chemical or isotopic proxies. These proxies can be measured in natural archives (e.g. bivalve shells and coral skeletons). One aspect of current climate change is the acidification of the oceans, a phenomenon caused by the oceanic uptake of anthropogenic CO2 and a resulting shift in the m...

  12. Past climate, future perspective: an exploratory analysis using climate proxies and drought risk assessment to inform water resources management and policy in Maine, USA.

    Science.gov (United States)

    Gupta, Avirup Sen; Jain, Shaleen; Kim, Jong-Suk

    2011-03-01

    In recent decades, significant progress has been made toward reconstructing the past climate record based on environmental proxies, such as tree rings and ice core records. However, limited examples of research that utilizes such data for water resources decision-making and policy exist. Here, we use the reconstructed record of Palmer Drought Severity Index (PDSI), dating back to 1138AD to understand the nature of drought occurrence (severity and duration) in the state of Maine. This work is motivated by the need to augment the scientific basis to support the water resources management and the emerging water allocation framework in Maine (Maine Department of Environmental Protection, Chapter 587). Through a joint analysis of the reconstructed PDSI and historical streamflow record for twelve streams in the state of Maine, we find that: (a) the uncertainties around the current definition of natural drought in the Chapter 587 (based on the 20th century instrumental record) can be better understood within the context of the nature and severity of past droughts in this region, and (b) a drought index provides limited information regarding at-site hydrologic variations. To fill this knowledge gap, a drought index-based risk assessment methodology for streams across the state is developed. Based on these results, the opportunities for learning and challenges facing water policies in a changing hydroclimate are discussed. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. Drought forecasting in Luanhe River basin involving climatic indices

    Science.gov (United States)

    Ren, Weinan; Wang, Yixuan; Li, Jianzhu; Feng, Ping; Smith, Ronald J.

    2017-11-01

    Drought is regarded as one of the most severe natural disasters globally. This is especially the case in Tianjin City, Northern China, where drought can affect economic development and people's livelihoods. Drought forecasting, the basis of drought management, is an important mitigation strategy. In this paper, we evolve a probabilistic forecasting model, which forecasts transition probabilities from a current Standardized Precipitation Index (SPI) value to a future SPI class, based on conditional distribution of multivariate normal distribution to involve two large-scale climatic indices at the same time, and apply the forecasting model to 26 rain gauges in the Luanhe River basin in North China. The establishment of the model and the derivation of the SPI are based on the hypothesis of aggregated monthly precipitation that is normally distributed. Pearson correlation and Shapiro-Wilk normality tests are used to select appropriate SPI time scale and large-scale climatic indices. Findings indicated that longer-term aggregated monthly precipitation, in general, was more likely to be considered normally distributed and forecasting models should be applied to each gauge, respectively, rather than to the whole basin. Taking Liying Gauge as an example, we illustrate the impact of the SPI time scale and lead time on transition probabilities. Then, the controlled climatic indices of every gauge are selected by Pearson correlation test and the multivariate normality of SPI, corresponding climatic indices for current month and SPI 1, 2, and 3 months later are demonstrated using Shapiro-Wilk normality test. Subsequently, we illustrate the impact of large-scale oceanic-atmospheric circulation patterns on transition probabilities. Finally, we use a score method to evaluate and compare the performance of the three forecasting models and compare them with two traditional models which forecast transition probabilities from a current to a future SPI class. The results show that the

  14. Climate Change Impacts and Responses: Societal Indicators for the National Climate Assessment

    Science.gov (United States)

    Kenney, Melissa A.; Chen, Robert S.; Maldonado, Julie; Quattrochi, Dale

    2011-01-01

    The Climate Change Impacts and Responses: Societal Indicators for the National Climate Assessment workshop, sponsored by the National Aeronautics and Space Administration (NASA) for the National Climate Assessment (NCA), was held on April 28-29, 2011 at The Madison Hotel in Washington, DC. A group of 56 experts (see list in Appendix B) convened to share their experiences. Participants brought to bear a wide range of disciplinary expertise in the social and natural sciences, sector experience, and knowledge about developing and implementing indicators for a range of purposes. Participants included representatives from federal and state government, non-governmental organizations, tribes, universities, and communities. The purpose of the workshop was to assist the NCA in developing a strategic framework for climate-related physical, ecological, and socioeconomic indicators that can be easily communicated with the U.S. population and that will support monitoring, assessment, prediction, evaluation, and decision-making. The NCA indicators are envisioned as a relatively small number of policy-relevant integrated indicators designed to provide a consistent, objective, and transparent overview of major variations in climate impacts, vulnerabilities, adaptation, and mitigation activities across sectors, regions, and timeframes. The workshop participants were asked to provide input on a number of topics, including: (1) categories of societal indicators for the NCA; (2) alternative approaches to constructing indicators and the better approaches for NCA to consider; (3) specific requirements and criteria for implementing the indicators; and (4) sources of data for and creators of such indicators. Socioeconomic indicators could include demographic, cultural, behavioral, economic, public health, and policy components relevant to impacts, vulnerabilities, and adaptation to climate change as well as both proactive and reactive responses to climate change. Participants provided

  15. Lake biota response to human impact and local climate during the last 200 years: A multi-proxy study of a subalpine lake (Tatra Mountains, W Carpathians).

    Science.gov (United States)

    Hamerlík, Ladislav; Dobríková, Daniela; Szarlowicz, Katarzyna; Reczynski, Witold; Kubica, Barbara; Šporka, Ferdinand; Bitušík, Peter

    2016-03-01

    Element content, loss-on-ignition, chironomid analysis and (210)Pb dating were applied on a sediment core from a subalpine Tatra lake (Popradské pleso) to reveal the response of aquatic biota to eutrophication induced by human activities in the lake catchment. The lead dating indicates that the 0-8 cm section of the core represents the past ca 200 years, ending at ~1814 AD. Comparing the key changes of the proxies with human activities that are historically well documented, four phases of the recent lake development were distinguished: (1) a pre-tourism phase, (2) a phase of increasing touristic activity and early cottage development, (3) a phase of eutrophication, and (4) a phase of post-eutrophication. Neither touristic activity, nor early cottage development around the lake (1st and 2nd phases) had considerable influence on the chironomid assemblage structure or organic content of the lake. The most significant change both in chironomid assemblage structure and loss-on-ignition occurred during the 3rd phase, when a big tourist hotel was built close by the lake and started contaminating it via direct wastewater input. However, the structure of the chironomid assemblage has not changed significantly over time and the dominating taxa remained the same during the whole period. Parallel with the nutrient signal of the paleo assemblage, a secondary signal has been identified as the ratio of rheophilic taxa on total abundance that did not correlate with the sediment's organic content, and is most likely driven by local climatic oscillations. Changes of most of metal elements concentrations reflected rather bigger scale changes of industrial activities than local scale human disturbances. Our results indicate that hydromorphological properties can moderate the impact of organic pollution on the lake biota. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Relating ocean-atmospheric climate indices with Australian river streamflow

    Science.gov (United States)

    Shams, Md Shamim; Faisal Anwar, A. H. M.; Lamb, Kenneth W.; Bari, Mohammed

    2018-01-01

    The relationship between climate indices with Australian river streamflow (ASF) may provide valuable information for long-lead streamflow forecasting for Australian rivers. The current study examines the correlations between three climate indices (SST, 500 mb meridional wind -U500 and 500 mb geopotential height-Z500) and 135 unimpaired ASF gauges for 1971-2011 using the singular value decomposition (SVD) method. First, SVD method was applied to check the SST-ASF correlated regions of influence and then extended SST-ASF variabilities were used to determine the correlated regions within Z500 and U500 fields. Based on the teleconnection, the most correlated region (150°E to 105°W and 35°S to 5°N) was identified and its persistency was checked by lag analysis up to 2 years from seasonal to yearly time-scale. The results displayed positive correlation for the south and south-eastern part of Australia while negative correlation prevails in the north-eastern region (at 95% significance level). The most correlated region was found situated along the South Pacific Convergence Zone (SPCZ) axis which may be considered as a probable climate driver for ASF. The persistency of this region was checked by a separate climate indicator (mean vertical velocity-500 mb) and found prominent in dry period than the wet period. This persistent teleconnected region may be potentially useful for long-lead forecasting of ASF.

  17. Climate and landscape influence on indicators of lake carbon cycling through spatial patterns in dissolved organic carbon.

    Science.gov (United States)

    Lapierre, Jean-Francois; Seekell, David A; Del Giorgio, Paul A

    2015-12-01

    Freshwater ecosystems are strongly influenced by both climate and the surrounding landscape, yet the specific pathways connecting climatic and landscape drivers to the functioning of lake ecosystems are poorly understood. Here, we hypothesize that the links that exist between spatial patterns in climate and landscape properties and the spatial variation in lake carbon (C) cycling at regional scales are at least partly mediated by the movement of terrestrial dissolved organic carbon (DOC) in the aquatic component of the landscape. We assembled a set of indicators of lake C cycling (bacterial respiration and production, chlorophyll a, production to respiration ratio, and partial pressure of CO2 ), DOC concentration and composition, and landscape and climate characteristics for 239 temperate and boreal lakes spanning large environmental and geographic gradients across seven regions. There were various degrees of spatial structure in climate and landscape features that were coherent with the regionally structured patterns observed in lake DOC and indicators of C cycling. These different regions aligned well, albeit nonlinearly along a mean annual temperature gradient; whereas there was a considerable statistical effect of climate and landscape properties on lake C cycling, the direct effect was small and the overall effect was almost entirely overlapping with that of DOC concentration and composition. Our results suggest that key climatic and landscape signals are conveyed to lakes in part via the movement of terrestrial DOC to lakes and that DOC acts both as a driver of lake C cycling and as a proxy for other external signals. © 2015 John Wiley & Sons Ltd.

  18. Numerical Modelling of Speleothem and Dripwater Chemistry: Interpreting Coupled Trace Element and Isotope Proxies for Climate Reconstructions

    Science.gov (United States)

    Owen, R.; Day, C. C.; Henderson, G. M.

    2016-12-01

    Speleothem palaeoclimate records are widely used but are often difficult to interpret due to the geochemical complexity of the soil-karst-cave system. Commonly analysed proxies (e.g. δ18O, δ13C and Mg/Ca) may be affected by multiple processes along the water flow path from atmospheric moisture source through to the cave drip site. Controls on speleothem chemistry include rainfall and aerosol chemistry, bedrock chemistry, temperature, soil pCO2, the degree of open-system dissolution and prior calcite precipitation. Disentangling the effects of these controls is necessary to fully interpret speleothem palaeoclimate records. To quantify the effects of these processes, we have developed an isotope-enabled numerical model based on the geochemical modelling software PHREEQC. The model calculates dripwater chemistry and isotopes through equilibrium bedrock dissolution and subsequent iterative CO2 degassing and calcite precipitation. This approach allows forward modelling of dripwater and speleothem proxies, both chemical (e.g. Ca concentration, pH, Mg/Ca and Sr/Ca ratios) and isotopic (e.g. δ18O, δ13C, δ44Ca and radiocarbon content), in a unified framework. Potential applications of this model are varied and the model may be readily expanded to include new isotope systems or processes. Here we focus on calculated proxy co-variation due to changes in model parameters. Examples include: - The increase in Ca concentration, decrease in δ13C and increase in radiocarbon content as bedrock dissolution becomes more open-system. - Covariation between δ13C, δ44Ca and trace metal proxies (e.g. Mg/Ca) predicted by changing prior calcite precipitation. - The effect of temperature change on all proxies through the soil-karst-cave system. Separating the impact of soil and karst processes on geochemical proxies allows more quantitative reconstruction of the past environment, and greater understanding in modern cave monitoring studies.

  19. The reconstruction of past climate variability in the NW Indian Ocean based on a coral proxy record from the Maldives

    OpenAIRE

    Storz, David

    2010-01-01

    Until now, the NW Indian Ocean was sparsely covered with coral proxy records, and records from the Maldives Archipelago do not exist. The first such coral proxy record from the central Maldives is presented in this study. It originates from a massive Porites lutea (Quoy and Gaimard, 1833) colony that was sampled March 2007 in the lagoon of Rasdhoo Atoll (4°N/ 73°W), which is located in the central Maldives. The record spans a period of 90 yrs and reaches back to 1917 AD with monthly to bimont...

  20. Epiphytes as an Indicator of Climate Change in Hawaii

    Science.gov (United States)

    Kettwich, S. K.

    2013-12-01

    Although climate change threatens many ecosystems, current research in this field suggests tropical vegetation lags in response. Epiphytes, or arboreal vegetation, occupy tight, climate-defined niches compared with co-occurring life forms such as trees, yet there have been few studies of Hawaii's epiphyte communities. Because of Hawaii Island's natural climatic diversity, it is an ideal location to understand how these intrinsically climate sensitive plants interact with the atmosphere and evaluate how they may serve as a near-term indicator of climate change. Here we establish a baseline from which changes in corticolous epiphyte communities can be monitored as a leading indicator of likely forest changes by 1) investigating patterns of epiphyte abundance and species composition across elevation and precipitation gradients on windward Hawaii Island, and 2) using physiological measurements to investigate the relative importance of rain vs. fog in epiphyte-atmosphere interactions. The precipitation gradient keeps elevation constant at 1000m, while varying precipitation between 2,400 and 6,400 mm/year. The elevation gradient keeps rainfall constant at 3000mm/year, and varies elevation between 200 and 1750 m. Forest sites are dominated by Ohia Lehua (Metrosideros polymorpha) across broad geographic and climatological ranges thus allowing examination of epiphytes on this single host. We quantified bryophytes and vascular plants growing on Ohia trunks with standardized diameter and branching characteristics. Overall, epiphyte communities showed much finer scale responses to climate variation when compared with structurally dominant vegetation (which was broadly similar at all sites). The precipitation gradient exhibits a clear increase in abundance of all epiphyte groups and a definable increase in diversity with increasing rainfall. Results across the elevation gradient show a higher abundance of filmy ferns and bryophytes above the lifting condensation level (about

  1. Reconstruction of Antarctic climate change using ice core proxy records from the coastal Dronning Maud Land, East Antarctica

    Digital Repository Service at National Institute of Oceanography (India)

    Thamban, M.; Laluraj, C.M.; Naik, S.S.; Chaturvedi, A.

    with the proxy record of solar activity (sup (10) Be profile from a South Pole ice core), suggesting enhanced NO sub (3) – values during periods of reduced solar activity like the Dalton Minimum (approx. 1790-1830 AD) and Maunder Minimum (approx. 1640- 1710 AD...

  2. Bacterial tetraether membrane lipids in peat and coal: Testing the MBT-CBT temperature proxy for climate reconstruction

    NARCIS (Netherlands)

    Weijers, J.W.H.; Steinmann, P.; Hopmans, E.C.; Schouten, S.; Sinninghe Damsté, J.S.

    2011-01-01

    Peatlands are widespread and important natural archives of environmental change. Here we explore the potential of the recently introduced MBT-CBT proxy (methylation index and cyclisation ratio of branched tetraethers) to estimate past annual mean air temperature (MAT) based on the distribution of

  3. Bacterial tetraether membrane lipids in peat and coal: Testing the MBT-CBT temperature proxy for climate reconstruction

    NARCIS (Netherlands)

    Weijers, J.W.H.; Steinmann, P.; Hopmans, E.C.; Schouten, S.; Sinninghe Damsté, J.S.

    2011-01-01

    Peatlands are widespread and important natural archives of environmental change. Here we explore the potential of the recently introduced MBT–CBT proxy (methylation index and cyclisation ratio of branched tetraethers) to estimate past annual mean air temperature (MAT) based on the distribution of

  4. Rotifers as Indicators of Climate Change in the Antarctic Environments

    Science.gov (United States)

    Pociecha, Agnieszka

    2010-01-01

    An important question stated in the presented paper is: Could rotifers be the indicators of climate change in the Antarctic environments? Rotifers are one of the most important components of the invertebrate fauna of the Antarctic freshwater and terrestrial ecosystems. However, investigations of their distribution, diversity and an ecological role in the environment have been widely neglected, mainly due to the methodological and taxonomical difficulties. During the investigations 176 species of rotifers were found, including the endemic and cosmopolitan species. Their existence is directly proportional to microvariations of humidity factor. Scientists still have poor knowledge about the occurrence of rotifer species in recently studied habitats e.g. cryoconite holes, nunataks or soil. Probably rotifers could be the indicators of climate change in the Antarctic freshwater and terrestrial ecosystems but more investigations and monitoring studies are needed.

  5. Estimating daily climatologies for climate indices derived from climate model data and observations

    Science.gov (United States)

    Mahlstein, Irina; Spirig, Christoph; Liniger, Mark A; Appenzeller, Christof

    2015-01-01

    Climate indices help to describe the past, present, and the future climate. They are usually closer related to possible impacts and are therefore more illustrative to users than simple climate means. Indices are often based on daily data series and thresholds. It is shown that the percentile-based thresholds are sensitive to the method of computation, and so are the climatological daily mean and the daily standard deviation, which are used for bias corrections of daily climate model data. Sample size issues of either the observed reference period or the model data lead to uncertainties in these estimations. A large number of past ensemble seasonal forecasts, called hindcasts, is used to explore these sampling uncertainties and to compare two different approaches. Based on a perfect model approach it is shown that a fitting approach can improve substantially the estimates of daily climatologies of percentile-based thresholds over land areas, as well as the mean and the variability. These improvements are relevant for bias removal in long-range forecasts or predictions of climate indices based on percentile thresholds. But also for climate change studies, the method shows potential for use. Key Points More robust estimates of daily climate characteristics Statistical fitting approach Based on a perfect model approach PMID:26042192

  6. Impact of climate change in Switzerland on socioeconomic snow indices

    Science.gov (United States)

    Schmucki, Edgar; Marty, Christoph; Fierz, Charles; Weingartner, Rolf; Lehning, Michael

    2017-02-01

    Snow is a key element for many socioeconomic activities in mountainous regions. Due to the sensitivity of the snow cover to variations of temperature and precipitation, major changes caused by climate change are expected to happen. We analyze the evolution of some key snow indices under future climatic conditions. Ten downscaled and postprocessed climate scenarios from the ENSEMBLES database have been used to feed the physics-based snow model SNOWPACK. The projected snow cover has been calculated for 11 stations representing the diverse climates found in Switzerland. For the first time, such a setup is used to reveal changes in frequently applied snow indices and their implications on various socioeconomic sectors. Toward the end of the twenty-first century, a continuous snow cover is likely only guaranteed at high elevations above 2000 m a.s.l., whereas at mid elevations (1000-1700 m a.s.l.), roughly 50 % of all winters might be characterized by an ephemeral snow cover. Low elevations (below 500 m a.s.l.) are projected to experience only 2 days with snowfall per year and show the strongest relative reductions in mean winter snow depth of around 90 %. The range of the mean relative reductions of the snow indices is dominated by uncertainties from different GCM-RCM projections and amounts to approximately 30 %. Despite these uncertainties, all snow indices show a clear decrease in all scenario periods and the relative reductions increase toward lower elevations. These strong reductions can serve as a basis for policy makers in the fields of tourism, ecology, and hydropower.

  7. Biomarkers in a peat deposit in Northern Spain (Huelga de Bayas, Asturias) as proxy for climate variation.

    Science.gov (United States)

    López-Días, V; Borrego, A G; Blanco, C G; Arboleya, M; López-Sáez, J A; López-Merino, L

    2010-05-21

    Peatlands are peculiar ecosystems in which well-adapted communities grow and develop, recording the variation in climate and hydrological conditions inland. In addition necromass is well preserved and therefore peatlands can be used as palaeo-archives for environmental variation. In this work a peat core of depth 60 cm dated at the bottom of the peat deposit as ca. 250cal AD from Huelga de Bayas (Asturias, Northern Spain) was studied to a resolution of 2-4 cm to investigate the evolution of the environmental conditions in the area. Samples were extracted with a dichloromethane/methanol ratio of 3:1 and studied by means of gas chromatography (GC) and mass spectrometry (GC-MS) in order to identify possible biomarkers of climatic variation during the period of peat formation. Lipid biomarker study allows the identification of periods in which Sphagnum or higher plants preferentially contributed to the peat profile. The absolute dating of the profile combined with the n-alkane record displayed five episodes of wetter conditions around ca. 250 cal AD (Roman Warm Period), 1080 and 1270 cal AD (Medieval Warm Period), 1460 cal AD (Little Ice Age) and 1920 cal AD (Recent warming), which are consistent with climate evolution in the region. Pentacyclic triterpenoids with hopane skeleton derived from microorganisms and with oleanane skeleton derived from higher plants were identified. The presence of their ketone and acetyl-derivatives, along with the presence of unstable hopane configurations indicates a low maturity of the peat profile. A tendency for the functionalised triterpenoids to decrease with depth was observed in the profile. 2010 Elsevier B.V. All rights reserved.

  8. Accounting for land use in life cycle assessment: The value of NPP as a proxy indicator to assess land use impacts on ecosystems.

    Science.gov (United States)

    Taelman, Sue Ellen; Schaubroeck, Thomas; De Meester, Steven; Boone, Lieselot; Dewulf, Jo

    2016-04-15

    Terrestrial land and its resources are finite, though, for economic and socio-cultural needs of humans, these natural resources are further exploited. It highlights the need to quantify the impact humans possibly have on the environment due to occupation and transformation of land. As a starting point of this paper (1(st) objective), the land use activities, which may be mainly socio-culturally or economically oriented, are identified in addition to the natural land-based processes and stocks and funds that can be altered due to land use. To quantify the possible impact anthropogenic land use can have on the natural environment, linked to a certain product or service, life cycle assessment (LCA) is a tool commonly used. During the last decades, many indicators are developed within the LCA framework in an attempt to evaluate certain environmental impacts of land use. A second objective of this study is to briefly review these indicators and to categorize them according to whether they assess a change in the asset of natural resources for production and consumption or a disturbance of certain ecosystem processes, i.e. ecosystem health. Based on these findings, two enhanced proxy indicators are proposed (3(rd) objective). Both indicators use net primary production (NPP) loss (potential NPP in the absence of humans minus remaining NPP after land use) as a relevant proxy to primarily assess the impact of land use on ecosystem health. As there are two approaches to account for the natural and productive value of the NPP remaining after land use, namely the Human Appropriation of NPP (HANPP) and hemeroby (or naturalness) concepts, two indicators are introduced and the advantages and limitations compared to state-of-the-art NPP-based land use indicators are discussed. Exergy-based spatially differentiated characterization factors (CFs) are calculated for several types of land use (e.g., pasture land, urban land). Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Evaluation of drought indices at interannual to climate change timescales: a case study over the Amazon and Mississippi river basins

    Science.gov (United States)

    Joetzjer, E.; Douville, H.; Delire, C.; Ciais, P.; Decharme, B.; Tyteca, S.

    2012-11-01

    The present study compares three meteorological drought indices (scPDSI, SPI and SPEI respectively) and their ability to account for the variations of annual mean river discharge on both interannual and climate change timescales. The Standardized Runoff Index (SRI) is used as a proxy of river discharge. The Mississippi and Amazon river basins provide two contrasted testbeds for this analysis. All meteorological drought indices are derived from monthly 2-meter temperature and/or precipitation, using either gridded observations or outputs of a global climate model. The SPI based solely on precipitation is not outperformed by the SPEI (accounting for potential evapotranspiration) and the scPDSI (based on a simplified water balance) at detecting interannual SRI variations. Under increasing concentrations of greenhouse gases, the simulated response of the areal fraction in drought is highly index-dependent, suggesting that more physical water balance models are needed to account for the impact of global warming on hydrological droughts.

  10. New directions in hydro-climatic histories: observational data recovery, proxy records and the atmospheric circulation reconstructions over the earth (ACRE) initiative in Southeast Asia

    Science.gov (United States)

    Williamson, Fiona; Allan, Rob; Switzer, Adam D.; Chan, Johnny C. L.; Wasson, Robert James; D'Arrigo, Rosanne; Gartner, Richard

    2015-12-01

    The value of historic observational weather data for reconstructing long-term climate patterns and the detailed analysis of extreme weather events has long been recognized (Le Roy Ladurie, 1972; Lamb, 1977). In some regions however, observational data has not been kept regularly over time, or its preservation and archiving has not been considered a priority by governmental agencies. This has been a particular problem in Southeast Asia where there has been no systematic country-by-country method of keeping or preserving such data, the keeping of data only reaches back a few decades, or where instability has threatened the survival of historic records. As a result, past observational data are fragmentary, scattered, or even absent altogether. The further we go back in time, the more obvious the gaps. Observational data can be complimented however by historical documentary or proxy records of extreme events such as floods, droughts and other climatic anomalies. This review article highlights recent initiatives in sourcing, recovering, and preserving historical weather data and the potential for integrating the same with proxy (and other) records. In so doing, it focuses on regional initiatives for data research and recovery - particularly the work of the international Atmospheric Circulation Reconstructions over the Earth's (ACRE) Southeast Asian regional arm (ACRE SEA) - and the latter's role in bringing together disparate, but interrelated, projects working within this region. The overarching goal of the ACRE SEA initiative is to connect regional efforts and to build capacity within Southeast Asian institutions, agencies and National Meteorological and Hydrological Services (NMHS) to improve and extend historical instrumental, documentary and proxy databases of Southeast Asian hydroclimate, in order to contribute to the generation of high-quality, high-resolution historical hydroclimatic reconstructions (reanalyses) and, to build linkages with humanities researchers

  11. Molecular proxies for paleoclimatology

    Science.gov (United States)

    Eglinton, Timothy I.; Eglinton, Geoffrey

    2008-10-01

    We summarize the applications of molecular proxies in paleoclimatology. Marine molecular records especially are proving to be of value but certain environmentally persistent compounds can also be measured in lake sediments, loess deposits and ice cores. The fundamentals of this approach are the molecular parameters, the compound abundances and carbon, hydrogen, nitrogen and oxygen isotopic contents which can be derived by the analysis of sediment extracts. These afford proxy measures which can be interpreted in terms of the conditions which control climate and also reflect its operation. We discuss two types of proxy; those of terrigenous and those of aquatic origin, and exemplify their application in the study of marine sediments through the medium of ten case studies based in the Atlantic, Mediterranean and Pacific Oceans, and in Antarctica. The studies are mainly for periods in the present, the Holocene and particularly the last glacial/interglacial, but they also include one study from the Cretaceous. The terrigenous proxies, which are measures of continental vegetation, are based on higher plant leaf wax compounds, i.e. long-chain (circa C 30) hydrocarbons, alcohols and acids. They register the relative contributions of C 3 vs. C 4 type plants to the vegetation in the source areas. The two marine proxies are measures of sea surface temperatures (SST). The longer established one, (U 37K') is based on the relative abundances of C 37 alkenones photosynthesized by unicellular algae, members of the Haptophyta. The newest proxy (TEX 86) is based on C 86 glycerol tetraethers (GDGTs) synthesized in the water column by some of the archaeal microbiota, the Crenarchaeota.

  12. BUSINESS CLIMATE INDICATOR AS A PREDICTOR OF CROATIAN INDUSTRIAL PRODUCTION

    Directory of Open Access Journals (Sweden)

    Mirjana Čižmešija

    2010-12-01

    Full Text Available Business and Consumer Surveys (BCS are one of the most frequently used tools to assess economy’s cyclical behavior. Croatia has been conducting the surveys continually since 1995. Nevertheless, there is still a research niche in the Croatian BCS framework that has not been adequately represented. The Joint Harmonised EU Programme of Business and Consumer Surveys suggests Business Climate Indicator (BCI as a composite leading indicator of the economy as a whole. In accordance to the EU methodology, this paper examines managers’ qualitative assessments on five important variables related to their economic environment. Using factor analysis one factor was extracted from those five variables, representing the BCI. It’s predictive properties were analyzed with regards to Croatian industrial production using Granger causality test, impulse response and variance decomposition analysis. Results strongly confirm the precedence of BCI to the changes of Croatian industrial production, validating the importance of its introduction and utilization in Croatian economic cycles analysis.

  13. The significance of chemical, isotopic, and detrital components in three coeval stalagmites from the superhumid southernmost Andes (53°S) as high-resolution palaeo-climate proxies

    Science.gov (United States)

    Schimpf, Daniel; Kilian, Rolf; Kronz, Andreas; Simon, Klaus; Spötl, Christoph; Wörner, Gerhard; Deininger, Michael; Mangini, Augusto

    2011-02-01

    Stalagmites are important palaeo-climatic archives since their chemical and isotopic signatures have the potential to record high-resolution changes in temperature and precipitation over thousands of years. We present three U/Th-dated records of stalagmites (MA1-MA3) in the superhumid southern Andes, Chile (53°S). They grew simultaneously during the last five thousand years (ka BP) in a cave that developed in schist and granodiorite. Major and trace elements as well as the C and O isotope compositions of the stalagmites were analysed at high spatial and temporal resolution as proxies for palaeo-temperature and palaeo-precipitation. Calibrations are based on data from five years of monitoring the climate and hydrology inside and outside the cave and on data from 100 years of regional weather station records. Water-insoluble elements such as Y and HREE in the stalagmites indicate the amount of incorporated siliciclastic detritus. Monitoring shows that the quantity of detritus is controlled by the drip water rate once a threshold level has been exceeded. In general, drip rate variations of the stalagmites depend on the amount of rainfall. However, different drip-water pathways above each drip location gave rise to individual drip rate levels. Only one of the three stalagmites (MA1) had sufficiently high drip rates to record detrital proxies over its complete length. Carbonate-compatible element contents (e.g. U, Sr, Mg), which were measured up to sub-annual resolution, document changes in meteoric precipitation and related drip-water dilution. In addition, these soluble elements are controlled by leaching during weathering of the host rock and soils depending on the pH of acidic pore waters in the peaty soils of the cave's catchment area. In general, higher rainfall resulted in a lower concentration of these elements and vice versa. The Mg/Ca record of stalagmite MA1 was calibrated against meteoric precipitation records for the last 100 years from two regional

  14. Stable water isotopes of precipitation and firn cores from the northern Antarctic Peninsula region as a proxy for climate reconstruction

    Directory of Open Access Journals (Sweden)

    F. Fernandoy

    2012-03-01

    Full Text Available In order to investigate the climate variability in the northern Antarctic Peninsula region, this paper focuses on the relationship between stable isotope content of precipitation and firn, and main meteorological variables (air temperature, relative humidity, sea surface temperature, and sea ice extent. Between 2008 and 2010, we collected precipitation samples and retrieved firn cores from several key sites in this region. We conclude that the deuterium excess oscillation represents a robust indicator of the meteorological variability on a seasonal to sub-seasonal scale. Low absolute deuterium excess values and the synchronous variation of both deuterium excess and air temperature imply that the evaporation of moisture occurs in the adjacent Southern Ocean. The δ18O-air temperature relationship is complicated and significant only at a (multiseasonal scale. Backward trajectory calculations show that air-parcels arriving at the region during precipitation events predominantly originate at the South Pacific Ocean and Bellingshausen Sea. These investigations will be used as a calibration for ongoing and future research in the area, suggesting that appropriate locations for future ice core research are located above 600 m a.s.l. We selected the Plateau Laclavere, Antarctic Peninsula as the most promising site for a deeper drilling campaign.

  15. estimation of climatic parameters from solar indices using ground

    African Journals Online (AJOL)

    User

    measure the activities of the sun in the photo- sphere, the corona and ... measured at a wavelength of 10.7 cm in the UV region of the spectrum. ..... meteorological station. Solar UV radiation through the proxy Mg II, which is the index of the chromosphere, has negative forcing of. MAT in Kenya, except for MSA where there is.

  16. Global impact of a climate treaty if the Human Development Index replaces GDP as a welfare proxy

    NARCIS (Netherlands)

    van den Bergh, J.C.J.M.; Botzen, W.J.W.

    2018-01-01

    This is the first study that shifts the narrative of climate policy evaluation from one of GDP growth to a message of improving social welfare, as captured by the HDI. This could make it easier for political leaders and climate negotiators to publicly commit themselves to ambitious carbon emission

  17. Magnetic Properties of Soils from Sarimukti Landfill as Proxy Indicators of Pollution (Case Study: Desa Sarimukti, Kabupaten Bandung Barat)

    Science.gov (United States)

    Cita Novala, Gesti; Fitriani, Dini; Susanto, Kusnahadi; Hajar Kirana, Kartika

    2016-01-01

    Leachate is the liquid arises from waste disposal. It contains heavy metals and magnetic minerals. Leachate could penetrate into sub surface that cause soil contamination. We have studied magnetic properties of soils from three zones in the Sarimukti landfill. We measured magnetic susceptibility in dual frequency and temperature dependent of susceptibility. The results showed that magnetic susceptibility at low frequency (xlf) of soil samples have the value ranging from 50-1400 (x 10-8 m3/kg). It infers that the samples were dominated by ferrimagnetic minerals. The relative difference of magnetic susceptibility measured at two frequency (xfd(%)) are less than 4%. It indicates that magnetic minerals probably derived from anthropogenic sources. There is negative correlation between xlf and Xfd(%). It supports the analysis that the source of magnetic minerals is anthropogenic. The results of the temperature dependent magnetic susceptibility measurements showed that the peak of magnetic susceptibility in heating curve occurs at the temperature about 200°C and 500°C. After 500°C, heating curve rapidly decreases. It can be inferred that the dominant type of magnetic minerals in the samples is titanomagnetite.

  18. Pyrolytic indices of diagenetic transformation of lignin as biogeochemical proxies for soil organic matter quality and C storage potential

    Science.gov (United States)

    Jiménez-González, Marco A.; Almendros, Gonzalo; Álvarez, Ana M.; Jiménez-Morillo, Nicasio T.; González-Vila, Francisco J.

    2017-04-01

    The environmental factors involved in soil organic carbon sequestration remain unclear. The functional relationships between the macromolecular structure of the soil organic matter (SOM) and its resilience has been a constant in classical biogeochemical models. Other more recent hypotheses have postulated that preservation by soil minerals may play a chief role in the accumulation of stable SOM forms. However, additional experimental data are required to demonstrate a cause-to-effect relationship between preservation and stabilization. Some authors might consider that models neglecting the role of macromolecular structure are swapping cause and effect i.e., that SOM structurally flexible, weakly condensed and having 'open' structures is the one with high potential to interact with the soil mineral matrix, leading to stable microaggregates. In this study up to 35 topsoil samples (0-5 cm) were collected from different Spanish soils with contrasted values of organic C (the dependent variable), geological substrate and vegetation type. A wide array of uni- and multivariate chemometric models were applied to independent variables consisting of total abundances of the major aromatic compounds, i.e., alkylbenzenes and methoxyphenols released from whole soil samples using pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS). These two families of compounds were selected since they are classically considered to inform on the degree of microbial reworking of lignins, which is an important precursor of the aromatic moiety of the SOM. A series of pyrolytic surrogate indices (aiming to express SOM diagenetic transformation in relation to the original biogenic molecular composition) were especially successful in forecasting SOC, viz: a) ratio between alkylbenzenes and methoxyphenols, b) ratio between short-chain (C0-C4) and long-chain (>C4) alkylbenzenes, c) ratio between methoxyphenols and short-chain alkylbenzenes, and d) ratios between methoxyphenols with different side

  19. Century scale climatic rhythms in the equatorial Indian Ocean during the late Quaternary: Faunal and geochemical proxies from the Maldivian Archipelago

    Science.gov (United States)

    Sarkar, S.; Gupta, A. K.

    2012-04-01

    The equatorial Indian Ocean is swept by the Indian Ocean equatorial westerlies (IEW) which are strong during monsoon transitions in April-May and October-November, driving Eastward Equatorial Current (EEC) in the upper ocean. This study is based on the biogenic sediments from Ocean Drilling Program (ODP) Hole 716A, recovered beneath the narrow equatorial track (7 Degree North to 7 Degree South) along which the IEW prevail. We analyzed 300 Kyr record of benthic and planktic foraminifera, pteropods combined with stable isotope values measured on planktic foraminifer Globigerinoides ruber from 451 core samples to understand paleoceanographic and paleoclimatic changes in the equatorial Indian Ocean during the late Quaternary (~450 - 150 Kyrs). Factor and cluster analyses of the 53 highest-ranked benthic foraminiferal species enabled to identify five biofacies, indicating varied nature of deep-sea environments during the late Quaternary, with a major shift across the middle Brunhes epoch (across Marine Isotope Stage 9 and 8). Biofacies Robulus nicobarensis - Trifarina reussi (Rn-Tr), Uvigerina porrecta - Reussella simplex (Upo-Rs) and Cymbaloporetta squammosa - Bolivinita sp. (Cs-Bsp) document high organic flux with low oxygen paleoenvironment dominating before the mid-Brunhes event, similar to Globigerina bulloides population, while benthic foraminiferal biofacies Hoeglundina elegans - Miliolinella subrotunda (He-Ms) and Uvigerina peregrina - Quinqueloculina seminulum (Upe-Qs) record high seasonality in food supply with well-oxygenated deep water after ~300 Kyr. These changes are also visible in planktic foraminifera and pteropod record. In the present day, the strength of the IEW is inversely related to the Indian Ocean Dipole (IOD). The IEW weakened across MIS 9/8 during which time the IOD strengthened, causing heavy rains and floods over the equatorial East Africa and deficient rainfall over Australasia. The proxy response changed from low to high frequency cycles

  20. Middle to Late Pleistocene multi-proxy record of environmental response to climate change from the Vienna Basin, Central Europe (Austria)

    Science.gov (United States)

    Salcher, Bernhard C.; Frank-Fellner, Christa; Lomax, Johanna; Preusser, Frank; Ottner, Franz; Scholger, Robert; Wagreich, Michael

    2017-10-01

    Tectonic basins can represent valuable archives of the environmental history. Presented here are the stratigraphy and multi-proxy analyses of two adjacent alluvial fans in the Quaternary active parts of the Vienna Basin, situated at the interface of the Atlantic, European continental and Mediterranean climate. Deposits comprise a sequence of coarse-grained fluvial deposits intercalated by laterally extensive horizons of pedogenically altered fine sediments. To establish palaeoenvironmental reconstructions, fine-grained sequences from a drill core and outcrop data were analysed according to its malacofauna, palaeopedology, susceptibility and sedimentology. The chronological framework is provided by 38 luminescence ages and supported by geomagnetic polarity investigations. Distinct warm periods each associated with a geomagnetic excursion, are recorded in three pedocomplexes formed during the Last Interglacial and two earlier interglacial periods, indicted to correlate with Marine Isotope Stage (MIS) 9 and MIS 11, respectively. Environmental conditions during the early last glacial period (MIS 5, c. 100-70 ka) are reconstructed from mollusc-shell rich overbank fines deposited along a former channel belt, covered by massive sheetflood deposits during MIS 2. Analysed warm phases suggest strong variations in humidity, ranging from steppe to forest dominated environments. The study presents one of the few numerically dated Middle Pleistocene multi-proxy records and one of the most comprehensive malacological datasets covering the early phases of last glacial period of continental Europe.

  1. Handwashing in 51 Countries: Analysis of Proxy Measures of Handwashing Behavior in Multiple Indicator Cluster Surveys and Demographic and Health Surveys, 2010-2013.

    Science.gov (United States)

    Kumar, Swapna; Loughnan, Libbet; Luyendijk, Rolf; Hernandez, Orlando; Weinger, Merri; Arnold, Fred; Ram, Pavani K

    2017-08-01

    In 2009, a common set of questions addressing handwashing behavior was introduced into nationally representative Demographic and Health Surveys (DHS) and Multiple Indicator Cluster Surveys (MICS), providing large amounts of comparable data from numerous countries worldwide. The objective of this analysis is to describe global handwashing patterns using two proxy indicators for handwashing behavior from 51 DHS and MICS surveys conducted in 2010-2013: availability of soap anywhere in the dwelling and access to a handwashing place with soap and water. Data were also examined across geographic regions, wealth quintiles, and rural versus urban settings. We found large disparities for both indicators across regions, and even among countries within the same World Health Organization region. Within countries, households in lower wealth quintiles and in rural areas were less likely to have soap anywhere in the dwelling and at designated handwashing locations than households in higher wealth quintiles and urban areas. In addition, disparities existed among various geographic regions within countries. This analysis demonstrates the need to promote access to handwashing materials and placement at handwashing locations in the dwelling, particularly in poorer, rural areas where children are more vulnerable to handwashing-preventable syndromes such as pneumonia and diarrhea.

  2. High-Arctic climate conditions for the last 7000 years inferred from multi-proxy analysis of the Bliss Lake record, North Greenland

    DEFF Research Database (Denmark)

    Olsen, Jesper; Kjær, Kurt H.; Funder, Svend Visby

    2012-01-01

    , Peary Land, Greenland. The early Holocene (10 850–10 480 cal. a BP) is characterized by increased erosion and gradually more marine conditions. Full marine conditions developed from 10 480 cal. a BP until the lake was isolated at 7220 cal. a BP. From its marine isolation at 7220 cal. a BP Bliss Lake...... becomes a lacustrine environment. Evidence from geochemical proxies (δ13C and total organic carbon) suggests that warmer conditions prevailed between 7220 and 6500 cal. a BP, corresponding to the Holocene thermal maximum, and from 3300 until 910 cal. a BP. From 850 to 500 cal. a BP colder climate...

  3. Register of the last 1000 years of environmental, climatic and anthropogenic change in Isla Grande de Chiloé, inferred through a multi-proxy approach: Lake Pastahué, Chile-South Center (42°S)

    Science.gov (United States)

    Troncoso, Jose; Alvarez, Denisse; Díaz, Gustavo; Fierro, Pablo; Araneda, Alberto; Torrejón, Fernando; Rondanelli, Mauricio; Fagel, Nathalie; Urrutia, Roberto

    2017-04-01

    Knowledge of the past environmental and climatic conditions of the lake ecosystems of the Isla Grande de Chiloé and its relationship with the anthropic effect, on a high temporal resolution scale, is scarcely known. Specifically, multi-proxy studies provide a better understanding of the context in which changes occurred in the past. This insular region is particularly interesting because environmental conditions (pre and post-Hispanic) and knowledge about the impacts generated in the ecosystems during the Spanish colonization process have so far been little studied, compared to the rest of Chile continental. This research is a new contribution to the scarce information existing for the last millennium of the Isla Grande de Chiloé. The objective of this work was to reconstruct the environmental and climatic history of the last 1000 years, from the Lake Pastahué, in the Isla Grande de Chiloé through a multi-proxy analysis and compare them with other records for the region. The core sediment was sub-sampled to perform sedimentological analysis (organic matter, carbonates, magnetic susceptibility and granulometry) and biological indicators (pollen, chironomids). The age model was constructed from the activity of 210Pb,137Cs and 14C. The pollen results reveal a composition of nordpatagónico forest represented by Nothofagus, Weinmannia, Drimys, Tepualia, Myrtaceae, Poaceae and Pteridophyta, while the anthropic effect for the last cm of the profile is represented by Rumex and Pinus. The results show a significant increase in magnetic susceptibility since the middle of the 20th century, suggesting an increase in allochthonous material to the lake. The sedimentological parameters and the chironomid assembly show similar variations along the profile, which also shows changes in the trophic state of the lake. The changes recorded in lake Pastahue are directly related to past climatic phenomena occurring in the last millennium, such as the medieval climatic anomaly (MCA

  4. Geochemistry of recent aragonite-rich sediments in Mediterranean karstic marine lakes: Trace elements as pollution and palaeoredox proxies and indicators of authigenic mineral formation.

    Science.gov (United States)

    Sondi, Ivan; Mikac, Nevenka; Vdović, Neda; Ivanić, Maja; Furdek, Martina; Škapin, Srečo D

    2017-02-01

    This study investigates the geochemical characteristics of recent shallow-water aragonite-rich sediments from the karstic marine lakes located in the pristine environment on the island of Mljet (Adriatic Sea). Different trace elements were used as authigenic mineral formation, palaeoredox and pollution indicators. The distribution and the historical record of trace elements deposition mostly depended on the sedimentological processes associated with the formation of aragonite, early diagenetic processes governed by the prevailing physico-chemical conditions and on the recent anthropogenic activity. This study demonstrated that Sr could be used as a proxy indicating authigenic formation of aragonite in a marine carbonate sedimentological environment. Distribution of the redox sensitive elements Mo, Tl, U and Cd was used to identify changes in redox conditions in the investigated lake system and to determine the geochemical cycle of these elements through environmental changes over the last 100 years. The significant enrichment of these elements and the presence of early formed nanostructured authigenic framboidal pyrite in laminated deeper parts of sediment in Malo Jezero, indicate sporadic events of oxygen-depleted euxinic conditions in the recent past. Concentrations of trace elements were in the range characteristic for non-contaminated marine carbonates. However, the increase in the concentrations of Zn, Cu, Pb, Sn, Bi in the upper-most sediment strata of Veliko Jezero indicates a low level of trace element pollution, resulting from anthropogenic inputs over the last 40 years. The presence of butyltin compounds (BuTs) in the surface sediment of Veliko Jezero additionally indicates the anthropogenic influence in the recent past. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Spring Indices (SI): National (and Global) Indicators of Climate Impacts on Ecosystems and Society

    Science.gov (United States)

    Betancourt, J. L.; Schwartz, M. D.; Ault, T. R.; McCabe, G. J.; Macalady, A. K.; Pederson, G. T.; Cook, B. P.; Henebry, G. M.; Moore, D. J.; Enquist, C.

    2011-12-01

    Indicators are vital in everyday life, such as tracking blood pressure to assess your health or monitoring the nation's economy using unemployment rates. Tracking the state of the environment in a uniform and integrated manner requires simple and broadly-applicable indicators of year-to-year variability and change. For example, indices such as the Start of Season (SOS) in remotely-sensed land surface phenology, Center of Mass (CM) in the hydrology of snowfed inland waters, and other biogeophysical metrics are being widely used as metrics of global change in seasonal timing. Here, we present a new, standardized spring index (SSI) that uses only daily minimum and maximum temperatures as input. This builds on an earlier version of the spring indices (SI) for lilac and honeysuckle phenology (first leaf and first flower) that required plant chilling to be satisfied over winter. The SSI tracks the transition from winter to spring by tallying phenologically relevant variables, (such as the number and intensity of warm days and total hours of sunlight) from January 1st onward, while ignoring the chilling requirement. This adjustment allows determination of first leaf and first bloom dates across the entire USA, including southernmost latitudes. Outputs from the new SSI is highly correlated with the earlier version, and both models process weather data into indices directly related to growth and development of many plants. Spatially averaged anomalies of SSI are well correlated with remotely sensed data and phenological observations from a wide variety of trees and shrubs in Europe, China, and North America. An advantage of SSI is that it only "sees" the atmosphere, meaning that it is free of local biological effects. Therefore, it can enhance the ability to identify important relationships between the large-scale climate modes of variability and the index itself, an advantage over other plant-based indices (such as SOS). If the state of these atmospheric modes can be

  6. Indicators for the 'Convention on biodiversity 2010". Influence of climate change on biodiversity

    NARCIS (Netherlands)

    Nijhof, B.S.J.; Vos, C.C.; Strien, van A.J.

    2007-01-01

    This report takes the first steps for the development of a climate change indicator system, based on the different responses of species to climate change. The usefulness of several climate change indicators is tested, by analyzing the relation between indicators and population trends of target

  7. Assessing climatic trends of extreme rainfall indices over northeast Bangladesh

    Science.gov (United States)

    Basher, Md. Abul; Stiller-Reeve, Mathew Alexander; Saiful Islam, A. K. M.; Bremer, Scott

    2017-10-01

    This study analyzes the trends of extreme rainfall indices over northeast Bangladesh for the period of 1984 to 2016 for the pre-monsoon and monsoon seasons. The research was framed as part of a project co-producing knowledge of climate variability and impacts through collaboration between scientific and local communities in northeast Bangladesh, which found pre-monsoon and monsoon rainfall to be most important. With access to a greater number of rainfall stations than previous work in northeast Bangladesh, we investigated trends in extreme rainfall events using the Mann-Kendall trend test and Sen's slope estimator. To appraise the quality of the data, we used the Standard Normal Homogeneity and the Pettitt tests to check its homogeneity. Among the seven stations, only Sunamganj was found inhomogeneous, and was not considered for trend analysis. All indices of rainfall extremes showed a decreasing trend in both seasons, with the most significant decrease during the monsoon. Importantly, we saw a decreasing trend in the seasonal total rainfall and consecutive wet days, whereas there was an increasing trend in consecutive dry days. Moreover, we saw a decreasing trend in 1-day maximum rainfall, 5-day maximum rainfall, the intensity of the daily rainfall over 25 mm during the pre-monsoon and 50 mm during monsoon, which together may indicate a future decrease in the magnitude and intensity of flash floods and monsoon floods. If this trend continues, the northeast Bangladesh may suffer from water stress, which could affect the lives and livelihoods of communities living there.

  8. Weather and Climate Indicators for Coffee Rust Disease

    Science.gov (United States)

    Georgiou, S.; Imbach, P. A.; Avelino, J.; Anzueto, F.; del Carmen Calderón, G.

    2014-12-01

    Coffee rust is a disease that has significant impacts on the livelihoods of those who are dependent on the Central American coffee sector. Our investigation has focussed on the weather and climate indicators that favoured the high incidence of coffee rust disease in Central America in 2012 by assessing daily temperature and precipitation data available from 81 weather stations in the INSIVUMEH and ANACAFE networks located in Guatemala. The temperature data were interpolated to determine the corresponding daily data at 1250 farms located across Guatemala, between 400 and 1800 m elevation. Additionally, CHIRPS five day (pentad) data has been used to assess the anomalies between the 2012 and the climatological average precipitation data at farm locations. The weather conditions in 2012 displayed considerable variations from the climatological data. In general the minimum daily temperatures were higher than the corresponding climatology while the maximum temperatures were lower. As a result, the daily diurnal temperature range was generally lower than the corresponding climatological range, leading to an increased number of days where the temperatures fell within the optimal range for either influencing the susceptibility of the coffee plants to coffee rust development during the dry season, or for the development of lesions on the coffee leaves during the wet season. The coffee rust latency period was probably shortened as a result, and farms at high altitudes were impacted due to these increases in minimum temperature. Factors taken into consideration in developing indicators for coffee rust development include: the diurnal temperature range, altitude, the environmental lapse rate and the phenology. We will present the results of our study and discuss the potential for each of the derived weather and climatological indicators to be used within risk assessments and to eventually be considered for use within an early warning system for coffee rust disease.

  9. Stable carbon and oxygen isotope chronologies from Araucaria angustifolia trees as proxies for investigating the impacts of Andean volcanism on South-Eastern American climate

    Science.gov (United States)

    Churakova (Sidorova), Olga; Saurer, Matthias; Evangelista da Silva, Heitor; Prestes, Alan; Corona, Christophe; Guillet, Sèbastien; Siegwolf, Rolf; Stoffel, Markus

    2017-04-01

    Stratospheric volcanic eruptions may lead to global cooling effects due to decreasing incoming solar radiation and perturbation of atmospheric circulation masses. Tree rings as indirect climate proxies, are able to capture information about temperature and precipitation changes from seasonal to annual scale. During past decades, studies of the impact of volcanic eruptions on tree-rings as well as stable isotopes in tree rings were focused mostly on the Northern Hemisphere. However, little attention has been paid to the Southern Hemisphere, particular to South America. Therefore, our goal is to quantify the impacts of Andean volcanism on Eastern South American climate in terms of temperature and hydrological changes over the past half millennium. To reconstruct past hydroclimatic and temperature changes after the 12 largest volcanic eruptions of the past 500 years we analyzed carbon and oxygen stable isotopes from cellulose chronologies from Araucaria angustifolia, indigenous climate sensitive conifer species from General Carneiro, State of Paraná, Brazil. The species distribution in southern Brazil is limited between the latitudes of 18° and 30° south, where species occurrence is often associated with Atlantic forest remnants, in mono dominant or mixed forest matrices. To date, a database of 20 tree-ring width chronologies is currently available and spans the last 634 years. We analyzed that material for precipitation and temperature anomalies, and model allocation of atmospheric circulation patterns after major volcanic eruptions. This will improve our understanding of driving factors of Southern Hemispheric climate over the past centuries. Acknowledgements: This work was supported by Brazilian-Swiss Joint Research Programme (BSJRP).

  10. Geomorphic responses as indicators of paleoclimate and climatic change

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

    There is little doubt that climate is an important parameter affecting the shape of the Earth`s surface. However absolute observance to the principles of climatic geomorphology leads us away from the study of processes because the analyses passes directly from climate to landscape form. An alternative approach is to examine the effects of climate change on the nature of the processes operating in the near surface environment. Utilizing this methodology, the climate-process relations take on greater significance, and lead to an understanding of the response(s) of geomorphic systems to shifts in climatic regime. Given that geomorphic systems respond to changes in climate regime, it should also be true that delineation of the changes in the types, rates, and magnitudes of geomorphic processes will provide insights into the timing and nature of past shifts in climate, particularly effective moisture. It is this approach that has been utilized herein. Specifically, geomorphic responses in eolian, lacustrine, and fluvial systems that have resulted in erosional and depositional events have been documented for several sites in Nevada (Figure 1), and used to infer the timing and character of climatic change in the Basin and Range Physiographic Province. The results and conclusions of the specific studies are provided.

  11. Environmental health indicators of climate change for the United States: findings from the State Environmental Health Indicator Collaborative.

    Science.gov (United States)

    English, Paul B; Sinclair, Amber H; Ross, Zev; Anderson, Henry; Boothe, Vicki; Davis, Christine; Ebi, Kristie; Kagey, Betsy; Malecki, Kristen; Shultz, Rebecca; Simms, Erin

    2009-11-01

    To develop public health adaptation strategies and to project the impacts of climate change on human health, indicators of vulnerability and preparedness along with accurate surveillance data on climate-sensitive health outcomes are needed. We researched and developed environmental health indicators for inputs into human health vulnerability assessments for climate change and to propose public health preventative actions. We conducted a review of the scientific literature to identify outcomes and actions that were related to climate change. Data sources included governmental and nongovernmental agencies and the published literature. Sources were identified and assessed for completeness, usability, and accuracy. Priority was then given to identifying longitudinal data sets that were applicable at the state and community level. We present a list of surveillance indicators for practitioners and policy makers that include climate-sensitive health outcomes and environmental and vulnerability indicators, as well as mitigation, adaptation, and policy indicators of climate change. A review of environmental health indicators for climate change shows that data exist for many of these measures, but more evaluation of their sensitivity and usefulness is needed. Further attention is necessary to increase data quality and availability and to develop new surveillance databases, especially for climate-sensitive morbidity.

  12. Global mean sea level - Indicator of climate change

    Science.gov (United States)

    Robock, A.; Hansen, J.; Gornitz, V.; Lebedeff, S.; Moore, E.; Etkins, R.; Epstein, E.

    1983-01-01

    A critical discussion is presented on the use by Etkins and Epstein (1982) of combined surface air temperature and sea level time series to draw conclusions concerning the discharge of the polar ice sheets. It is objected by Robock that they used Northern Hemisphere land surface air temperature records which are unrepresentative of global sea surface temperature, and he suggests that externally imposed volcanic dust and CO2 forcings can adequately account for observed temperature changes over the last century, with global sea level changing in passive response to sea change as a result of thermal expansion. Hansen et al. adduce evidence for global cooling due to ice discharge that has not exceeded a few hundredths of a degree centigrade in the last century, precluding any importance of this phenomenon in the interpretation of global mean temperature trends for this period. Etkins and Epstein reply that since their 1982 report additional evidence has emerged for the hypothesis that the polar ice caps are diminishing. It is reasserted that each of the indices discussed, including global mean sea surface temperature and sea level, polar ice sheet mass balance, water mass characteristics, and the spin rate and axis of rotation displacement of the earth, are physically linked and can be systematically monitored, as is currently being planned under the auspices of the National Climate Program.

  13. High vs low latitude sequence of events over the last deglaciation using ice core isotopic proxies and an isotope-enabled climate model

    Science.gov (United States)

    Landais, Amaelle; Roche, Didier; Prié, Frédéric; Minster, Bénédicte; Masson-Delmotte, Valérie; Vinther, Bo; Capron, Emilie; Popp, Trevor; Rhodes, Rachael

    2017-04-01

    The last deglaciation is recorded with annual resolution in the ice d18O records from Greenland ice cores. In addition to long term change associated with orbital variations, the last deglaciation is associated with abrupt changes in the northern hemisphere with the sequence of Heinrich 1, Bølling-Allerød and Younger Dryas. The combination of orbital and millennial scale variability during deglaciations has also been recorded in many other continental and marine records. Still, the underlying mechanism linking orbital and millennial changes over deglaciation is not fully understood. Limitations come from the exact description of the sequence of events between external forcing, high and low latitudes climate and environmental changes. In order to progress on this issue, our study combines low and high latitudes climate proxies measured in ice cores as well as transient modeling simulations of the last deglaciation run with an intermediate complexity model equipped with water isotopes (iLOVECLIM). New high resolution measurements of 17O-excess and d-excess from the NorthGRIP ice core covering the last deglaciation are used to decipher the local from the distant effect on the water isotopic records measured in Greenland ice cores. These second order parameters are indeed sensitive to climatic conditions at the oceanic evaporative regions and to the trajectories of the water mass toward the polar precipitation sites. These new measurements clearly highlight a decoupling between Greenland and lower latitudes over the time period corresponding to Heinrich event 1. This time period is recorded as a two phase sequence in the 17O-excess and d-excess records. This two phase sequence is confirmed by atmospheric d18O (d18Oatm) data from ice cores covering the same time period. d18O atm is a global atmospheric signal measured on the air trapped in ice cores interpreted as a proxy for low latitude water cycle that can be compared to calcite d18O records from East Asian caves

  14. Multi-decadal variation in southern California drought during the Medieval Climate Anomaly and Little Ice Age (~800AD-~1800AD) - evidence from coeval terrestrial and marine proxies

    Science.gov (United States)

    Heusser, L. E.; Hendy, I. L.; Barron, J. A.; Pak, D. K.

    2012-12-01

    High resolution studies of precipitation proxies (pollen from coastal, drought-resistant chaparral and upslope mesic oak-pine woodlands, and bulk sediment Ti%) from sediments deposited in Santa Barbara Basin (SPR0901-02kc; 34°16.845N, 120°02.332W, water depth 588 m) reflect decadal-scale fluctuations in persistent severe drought spanning from ~800 to 1270AD. Pollen from chamise and manzanita chaparrals (sclerophyllous woody shrubs dominated by Adenostoma and Arctostaphylos) begins to decline at ~1265AD, while oak-pine woodlands begin to increase at ~1211AD reaching a maximum between ~1500-~1600AD. Termination of the last major drought in our record coincides with that of major drought events elsewhere in the West (Stine, 1994; Cook et al, 2004), and marks the beginning of gradual, fluctuating increases in precipitation and in coastal southern California mesic, oak-dominated communities. Offshore, diatom, oxygen isotopes, and planktonic foraminifera data imply cold spring and warm winter sea surface temperatures during the Medieval Climate Anomaly (MCA) that reverse in the Little Ice Age (LIA). These major climate-driven changes in southern California and Santa Barbara Basin are consistent with changes in northern hemisphere circulation, i.e., weakened Arctic Lows, strengthened North Pacific Highs and extended La Niña-like conditions during the MCA and strengthened Aleutian Lows, weakened and westward North Pacific Highs and extended El Niño-like atmospheric conditions during the LIA.

  15. Development of A Dust Climate Indicator for the US National Climate Assessment

    Science.gov (United States)

    Tong, D.; Wang, J. X. L.; Gill, T. E.; Van Pelt, S.; Kim, D.

    2016-12-01

    Dust activity is a relatively simple but practical indicator to document the response of dryland ecosystems to climate change, making it an integral part of the National Climate Assessment (NCA). We present here a multi-agency collaboration that aims at developing a suite of dust climate indicators to document and monitor the long-term variability and trend of dust storm activity in the western United States. Recent dust observations have revealed rapid intensification of dust storm activity in the western United States. This trend is also closely correlated with a rapid increase in dust deposition in rainwater and "valley fever" hospitalization in southwestern states. It remains unclear, however, if such a trend, when enhanced by predicted warming and rainfall oscillation in the Southwest, will result in irreversible environmental development such as desertification or even another "Dust Bowl". Based on continuous ground aerosol monitoring, we have reconstructed a long-term dust storm climatology in the western United States. We report here direct evidence of rapid intensification of dust storm activity over US deserts in the past decades (1990 to 2013), in contrast to the decreasing trends in Asia and Africa. The US trend is spatially and temporally correlated with incidences of valley fever, an infectious disease caused by soil-dwelling fungus that has increased eight-fold in the past decade. We further investigate the linkage between dust variations and possible climate drivers and find that the regional dust trends are likely driven by large-scale variations of sea surface temperature in the Pacific Ocean, with the strongest correlation with the Pacific Decadal Oscillation (PDO). Future study will explore the link between the temporal and spatial trends of increase in dustiness and vegetation change in southwestern semi-arid and arid ecosystems.

  16. Holocene fluvial geochronologies, global databases and hydrological proxies: rethinking people-river interactions and rapid climate change impacts (Invited)

    Science.gov (United States)

    Macklin, M. G.

    2009-12-01

    The assumption of the constancy of climate over time periods of around a century, which was the basis of much engineering and hydrological forward planning until recently, is now widely felt to be unsatisfactory. This re-evaluation has been prompted by a number of important empirical, interdisciplinary and technological advances in fluvial science research over the last decade that is increasingly being carried out in a global framework. Some of the more important developments have included: 1. wider application of high precision sediment-based dating techniques (e.g. OSL) to a greater range of fluvial environments; 2. worldwide database compilation and statistical analysis of 14C dated Holocene fluvial units, enabling the identification of climatic and anthropogenic environmental signals in fluvial sedimentary sequences; and 3. new earth surface observation (e.g. LIDAR) and sediment core analysis (e.g. ITRAX core scanner) techniques that are providing event-scale reconstructions of fluvial environments. Drawing on recent geoarchaeological research in the lower Nile valley, 14C database analysis and comparison of Holocene fluvial records in Europe and New Zealand, and a new 3700-year continuous flood record from the UK reconstructed from fine-grained floodplain sediments, the impact of rapid climate change on riverine societies resulting from monsoon, thermohaline circulation, ENSO and NAO variability is critically reviewed. These studies show that establishing causal relationships between river dynamics and cultural/demographic change is not a straightforward task and identifying possible natural environmental triggers of societal change is especially problematic. A solution may be to stress the inseparable nature of environmental and cultural influences, and view the physical environment as a delimiter of possible action rather than as a prescriptive agency.

  17. Oxygen isotope ratios (18O/16O) of hemicellulose-derived sugar biomarkers in plants, soils and sediments as paleoclimate proxy I: Insight from a climate chamber experiment

    Science.gov (United States)

    Zech, Michael; Mayr, Christoph; Tuthorn, Mario; Leiber-Sauheitl, Katharina; Glaser, Bruno

    2014-02-01

    The oxygen isotopic composition of cellulose is a valuable proxy in paleoclimate research. However, its application to sedimentary archives is challenging due to extraction and purification of cellulose. Here we present compound-specific δ18O results of hemicellulose-derived sugar biomarkers determined using gas chromatography-pyrolysis-isotope ratio mass spectrometry, which is a method that overcomes the above-mentioned analytical challenges. The biomarkers were extracted from stem material of different plants (Eucalyptus globulus, Vicia faba and Brassica oleracea) grown in climate chamber experiments under different climatic conditions. The δ18O values of arabinose and xylose range from 31.4‰ to 45.9‰ and from 28.7‰ to 40.8‰, respectively, and correlate highly significantly with each other (R = 0.91, p automatic irrigation system, the relevance of the temperature and the Péclet effect in paleoclimate studies where water supply is actually often limited is presumably considerably lower than the relevance of relative air humidity. This assumption is confirmed by a climate transect study on δ18Ohemicellulose of modern topsoils presented in the companion paper by Tuthorn et al. (2014). Thirdly, a biosynthetic 18O fractionation of ˜+27‰ (Sternberg et al., 1986; Cernusak et al., 2003; Gessler et al., 2009) causes newly assimilated sugars and leaf cellulose to be systematically enriched in 18O compared to leaf water (Fig. 4). Recently, Sternberg and Ellsworth (2011) suggested that the biochemical 18O fractionation during cellulose synthesis is not constant but increases at lower temperatures to values of ˜+31‰. However, this conclusion is based on the assumption that the percentage of oxygen atoms exchanging during cellulose synthesis (pex) is constant and 42%. This assumption may not hold true, because although not statistically significant (p = 0.10, n = 6), there is a clear trend indicating that pex is not constant but temperature-dependent (ranging

  18. Climate resilient development index: theoretical framework, selection criteria and fit for purpose indicators

    OpenAIRE

    Miola, Apollonia; PACCAGNAN Vania; PAPADIMITRIOU ELENI; MANDRICI ANDREA

    2015-01-01

    This report aims to contribute to the debate on climate change policies and their link to development. A climate resilient perspective is adopted to understand how climate change policy objectives can be reconciled with development goals. The report reviews the main theoretical concepts that characterise the scientific literature on climate risk and vulnerability assessments, and identifies climate resilient fit-for-purpose indicators accordingly. This makes it possible to build the theoretic...

  19. Variation of a Lightning NOx Indicator for National Climate Assessment

    Science.gov (United States)

    Koshak, William; Vant-Hull, B.; McCaul, E. W.; Peterson, H. S.

    2014-01-01

    Lightning nitrogen oxides (LNOx) indirectly influences our climate since these molecules are important in controlling the concentration of ozone (O3) and hydroxyl radicals (OH) in the atmosphere [Huntrieser et al., 1998]. In support of the National Climate Assessment (NCA) program, satellite Lightning Imaging Sensor (LIS; Christian et al. [1999]; Cecil et al. [2014]) data is used to estimate LNOx production over the southern portion of the conterminous US for the 16 year period 1998-2013.

  20. Financial market response to extreme events indicating climatic change

    Science.gov (United States)

    Anttila-Hughes, J. K.

    2016-05-01

    A variety of recent extreme climatic events are considered to be strong evidence that the climate is warming, but these incremental advances in certainty often seem ignored by non-scientists. I identify two unusual types of events that are considered to be evidence of climate change, announcements by NASA that the global annual average temperature has set a new record, and the sudden collapse of major polar ice shelves, and then conduct an event study to test whether news of these events changes investors' valuation of energy companies, a subset of firms whose future performance is closely tied to climate change. I find evidence that both classes of events have influenced energy stock prices since the 1990s, with record temperature announcements on average associated with negative returns and ice shelf collapses associated with positive returns. I identify a variety of plausible mechanisms that may be driving these differential responses, discuss implications for energy markets' views on long-term regulatory risk, and conclude that investors not only pay attention to scientifically significant climate events, but discriminate between signals carrying different information about the nature of climatic change.

  1. Proxy consent: moral authority misconceived.

    Science.gov (United States)

    Wrigley, A

    2007-09-01

    The Mental Capacity Act 2005 has provided unified scope in the British medical system for proxy consent with regard to medical decisions, in the form of a lasting power of attorney. While the intentions are to increase the autonomous decision making powers of those unable to consent, the author of this paper argues that the whole notion of proxy consent collapses into a paternalistic judgement regarding the other person's best interests and that the new legislation introduces only an advisor, not a proxy with the moral authority to make treatment decisions on behalf of another. The criticism is threefold. First, there is good empirical evidence that people are poor proxy decision makers as regards accurately representing other people's desires and wishes, and this is therefore a pragmatically inadequate method of gaining consent. Second, philosophical theory explaining how we represent other people's thought processes indicates that we are unlikely ever to achieve accurate simulations of others' wishes in making a proxy decision. Third, even if we could accurately simulate other people's beliefs and wishes, the current construction of proxy consent in the Mental Capacity Act means that it has no significant ethical authority to match that of autonomous decision making. Instead, it is governed by a professional, paternalistic, best-interests judgement that undermines the intended role of a proxy decision maker. The author argues in favour of clearly adopting the paternalistic best-interests option and viewing the proxy as solely an advisor to the professional medical team in helping make best-interests judgements.

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

    Science.gov (United States)

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

    2015-01-01

    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.

  3. 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.

  4. Centennial-scale vegetation and climate changes in the Middle Atlas, Morocco: new insights from multi-proxy investigations at Lake Sidi Ali

    Science.gov (United States)

    Fletcher, William; Campbell, Jennifer; Joannin, Sebastien; Mischke, Steffen; Zielhofer, Christoph; de Batist, Marc; Mikdad, Abdes

    2016-04-01

    The karstic lakes of the Middle Atlas, Morocco, represent a valuable archive of environmental and climatic change for Northwest Africa. Here we present the results of centennial-scale palynological and charcoal analyses as part of a multiproxy palaeolimnological study of sediment cores from Lake Sidi Ali in the Middle Atlas, Morocco (33° 03 N, 05° 00 W; 2,080 m a.s.l.). Supported by absolute dating including 23 more than twenty AMS 14C dates on pollen concentrates, the record covers the entire Holocene and offers insights into vegetation and climate change at a regionally unprecedented centennial-scale. Pollen assemblages are dominated by steppic herbs, evergreen oaks (Quercus), junipers (Cupressaceae) and Atlantic cedar (Cedrus atlantica). A long-term evolution of the montane vegetation is recorded, reflecting progressive changes in the dominant arboreal taxa and leading to the full establishment of the emblematic cedar forests of the area during the mid-Holocene by 6000 cal BP. Orbital-scale changes in seasonality and growing season moisture availability linked to declining summer insolation are implicated, with a transition from (a) warm, dry summers associated with summer drought tolerant taxa especially evergreen Quercus, high algal productivity in the lake, and high background levels of microcharcoal reflecting distant fire activity during the early Holocene, to (b) cool, relatively humid summers with dominance of montane conifers, declining algal productivity in the lake, and episodic local fire activity during the mid- to late Holocene. Superimposed on the long-term environmental changes are recurrent centennial-scale fluctuations in vegetation composition, reflecting competitive dynamics between the major taxa, initially between steppic and arboreal elements, and later between the major tree taxa. Parallels with hydrological proxies including stable O and C isotopes suggest common responses to climatic drivers (fluctuations in moisture sources and

  5. Late-Holocene climate variability in southern New Zealand: A multi-proxy study of lake sediments from Lake Ohau to reconstruct regional climate

    Science.gov (United States)

    Roop, H. A.; Vandergoes, M. J.; Levy, R. H.; Dunbar, G.; Upton, P.; Stumpner, P.; Fitzsimons, S.; Howarth, J. D.; Ditchburn, R.; Wilson, G. S.; Purdie, J.

    2012-12-01

    Driving this research is the need to improve understanding of synoptic climate systems influencing climate in southern New Zealand and to document changes in the character of these systems beyond the historical record. Inter-annual variability of New Zealand's climate (e.g. temperature and precipitation) is influenced by large-scale patterns originating in both the tropics (El-Niño-Southern Oscillation, Interdecadal Pacific Oscillation) and the Antarctic (Southern Annular Mode). Currently, very few highly resolved climate reconstructions exist in mid-latitudes of the Southern Hemisphere. The identification of annually laminated sediments in Lake Ohau, Mackenzie Basin, New Zealand (44.234°S, 169.854°E) offers a unique opportunity to investigate changes in regional hydrology and climate, and by extension also explore connections to large-scale climate patterns. Importantly, Lake Ohau is situated east of and in the lee of the Southern Alps, rendering the region characteristically dry and sensitive to small fluctuations in precipitation and temperature. Short cores (<6 meters) from Lake Ohau contain layered sedimentary couplets, which 137Cs and 210Pb analyses suggest represent annual accumulation of terrigenous sediment at an average rate of 0.5 cm a-1. Core imaging (RGB, L*), density, and magnetic susceptibility data were acquired using a GeoTek multi-sensor core logger. Here we present an initial assessment of couplet characteristics based on thin-sections, grain size analysis, and GeoTek output. Extensive limnological monitoring, including acoustic Doppler profilers, thermister strings, sediment traps, and turbidity meters will help to further develop a detailed understanding of processes driving seasonal sediment deposition in Lake Ohau. These limnological data, and preliminary correlations with lake inflow data (1924-2012), and local precipitation and temperature data (1910-2012) will also be presented. This work provides the foundation for reconstructing the

  6. Diagnostic indicators for integrated assessment models of climate policy

    NARCIS (Netherlands)

    Kriegler, Elmar; Petermann, Nils; Krey, Volker; Schwanitz, Valeria Jana; Luderer, Gunnar; Ashina, Shuichi; Bosetti, Valentina; Eom, Jiyong; Kitous, Alban; Méjean, Aurélie; Paroussos, Leonidas; Sano, Fuminori; Turton, Hal; Wilson, Charlie; Van Vuuren, Detlef P.|info:eu-repo/dai/nl/11522016X

    2015-01-01

    Integrated assessments of how climate policy interacts with energy-economy systems can be performed by a variety of models with different functional structures. In order to provide insights into why results differ between models, this article proposes a diagnostic scheme that can be applied to a

  7. Small Mammals as Indicators of Climate, Biodiversity, and Ecosystem Change

    Science.gov (United States)

    Hope, Andrew G.; Waltari, Eric; Morse, Nathan R.; Flamme, M.J.; Cook, Joseph A.; Talbot, Sandra

    2017-01-01

    Climate is a driving evolutionary force for biodiversity in high-latitude Alaska. This region is complex and dynamic with high annual variation in temperature and light. Through deeper time, Alaska has experienced major climate extremes over much longer periodicity. For example, the Quaternary Period (the last ~2.5 million years), commonly known as the Ice Age, was punctuated by more than 20 major glacial-interglacial cycles. During glacial phases, water was locked up in ice sheets that covered much of North America, and the resulting lower sea levels exposed a land connection between Alaska and Siberia, a combined region known as Beringia (Figure 1). This isthmus provided vast expanses of land for species to inhabit, provided they could withstand potentially harsh polar conditions. Each extended glacial phase periodically transitioned into a shorter interglacial warm phase. These climate reversals melted continental ice sheets to expose corridors for reinvasion of terrestrial species, particularly those associated with forested habitats further south. Those species that survived at northern latitudes through repeated glacial-interglacial cycles formed the Arctic tundra communities that persist today. At present, Alaska supports diverse communities associated with both tundra and forests (Figure 2). These communities often interact with one another across latitudinal and elevational gradients, with tundra species generally found further north or higher in elevation. Alaska’s climate is continuing to change today, strongly influencing local environments and the distribution and dynamics of wildlife species.

  8. Lichen communities and species indicate climate thresholds in southeast and south-central Alaska, USA

    Science.gov (United States)

    Heather T. Root; Bruce. McCune; Sarah. Jovan

    2014-01-01

    Because of their unique physiology, lichen communities are highly sensitive to climatic conditions,making them ideal bioindicators for climate change. Southeast and south-central Alaska host diverse and abundant lichen communities and are faced with a more rapidly changing climate than many more southerly latitudes. We develop sensitive lichen-based indicators for...

  9. Proxy comparisons for Paleogene sea water temperature reconstructions

    Science.gov (United States)

    de Bar, Marijke; de Nooijer, Lennart; Schouten, Stefan; Ziegler, Martin; Sluijs, Appy; Reichart, Gert-Jan

    2017-04-01

    uncertainties in the seawater Mg/Ca model and the relationship between the seawater Mg/Ca and the incorporation of Mg into the foraminiferal shell. The U37K' index could not be calculated as only di-unsaturated alkenones were identified, indicating that SSTs were > 28 ˚ C. In contrast, LDI temperatures were considerably lower and varied only between 21 and 19 ˚ C. MBT'-CBT derived mean annual temperatures for the ages of 9 and 20 Ma align well with the TEX86H SSTs. Overall, the agreement of the paleotemperature proxies in terms of main tendencies, and the covariation with the global benthic oxygen isotope compilation suggests that temperatures in this region varied in concert with global climate variability. The fact that offsets between the different proxies used here remain fairly constant down to 90 Ma ago, indicates that the fundamental mechanisms responsible for the proxy relation to temperature remained constant. de Bar, M. W., et al. (2016), Constraints on the application of long chain diol proxies in the Iberian Atlantic margin, Org. Geochem., 101, 184-195. Hollis, C. J., et al. (2012), Early Paleogene temperature history of the Southwest Pacific Ocean: Reconciling proxies and models, Earth Planet. Sci. Lett., 349, 53-66. Sluijs, A., et al. (2011), Southern ocean warming, sea level and hydrological change during the Paleocene-Eocene thermal maximum, Climate of the Past, 7(1), 47-61.

  10. From cold to cool in northernmost Norway: Lateglacial and early Holocene multi-proxy environmental and climate reconstructions from Jansvatnet, Hammerfest

    Science.gov (United States)

    Birks, Hilary H.; Jones, Vivienne J.; Brooks, Stephen J.; Birks, H. John B.; Telford, Richard J.; Juggins, Stephen; Peglar, Sylvia M.

    2012-02-01

    A multi-proxy palaeoecological study of the lateglacial and early Holocene sediments of Jansvatnet, Hammerfest, northernmost Norway (70°39' N) showed that cold and arid conditions prevailed in both the lateglacial interstadial and the Younger Dryas. Terrestrial proxies are macrofossils and pollen. Aquatic proxies are plant and invertebrate macrofossils, pollen, diatoms, and chironomids. Mean July temperatures were reconstructed using pollen and chironomid calibration functions and ecological knowledge of the fossil flora and fauna. Lake-water pH was reconstructed using a diatom pH-calibration function. Above sterile basal deglacial silts, biotic activity was detected around 14600 years ago in the interstadial (chronologically equivalent to the Bølling-Allerød in the Greenland Ice-Core Chronology). Catchment vegetation resembled polar desert and ultra-cold stenothermic chironomids lived in the lake. However, diatom assemblages were diverse and dynamic. In the Younger Dryas stadial, conditions deteriorated. In the early Younger Dryas chironomid-inferred air temperatures (CI-Tjul) fell about 1 °C. Pollen-inferred temperatures (PI-Tjul) did not fall and the terrestrial vegetation hardly changed because of the extreme aridity. The lake water was turbid from suspended clay which diminished aquatic life. Later in the Younger Dryas (ca 12400 cal yr BP) reconstructed mean July temperatures fell by a further 3 °C and were close to the minimum to support life, at around 3-4 °C. However, decreased turbidity allowed moss growth on the lake bottom that provided habitats for invertebrates and diatoms. In the last 200 years of the Younger Dryas temperatures increased by 2-3 °C and terrestrial and aquatic organisms responded quickly. At the start of the Holocene a rapid increase of more than 3 °C in PI-Tjul to 9.5 °C initiated the replacement of sparse arctic tundra by low-arctic dwarf-shrub heath. Simultaneously, a further 2 °C increase in CI-Tjul to 10-11 °C reflected

  11. Pacific Islands Regional Climate Assessment: Building a Framework to Track Physical and Social Indicators of Climate Change Across Pacific Islands

    Science.gov (United States)

    Grecni, Z. N.; Keener, V. W.

    2016-12-01

    Assessments inform regional and local climate change governance and provide the critical scientific basis for U.S. climate policy. Despite the centrality of scientific information to public discourse and decision making, comprehensive assessments of climate change drivers, impacts, and the vulnerability of human and ecological systems at regional or local scales are often conducted on an ad hoc basis. Methods for sustained assessment and communication of scientific information are diverse and nascent. The Pacific Islands Regional Climate Assessment (PIRCA) is a collaborative effort to assess climate change indicators, impacts, and adaptive capacity of the Hawaiian archipelago and the US-Affiliated Pacific Islands (USAPI). In 2012, PIRCA released the first comprehensive report summarizing the state of scientific knowledge about climate change in the region as a technical input to the U.S. National Climate Assessment. A multi-method evaluation of PIRCA outputs and delivery revealed that the vast majority of key stakeholders view the report as extremely credible and use it as a resource. The current study will present PIRCA's approach to establishing physical and social indicators to track on an ongoing basis, starting with the Republic of the Marshall Islands as an initial location of focus for providing a cross-sectoral indicators framework. Identifying and tracking useful indicators is aimed at sustaining the process of knowledge coproduction with decision makers who seek to better understand the climate variability and change and its impacts on Pacific Island communities.

  12. Sensitivity of health sector indicators' response to climate change in Ghana.

    Science.gov (United States)

    Dovie, Delali B K; Dzodzomenyo, Mawuli; Ogunseitan, Oladele A

    2017-01-01

    There is accumulating evidence that the emerging burden of global climate change threatens the fidelity of routine indicators for disease detection and management of risks to public health. The threat partially reflects the conservative character of the health sector and the reluctance to adopt new indicators, despite the growing awareness that existing environmental health indicators were developed to respond to risks that may no longer be relevant, and are too simplistic to also act as indicators for newer global-scale risk factors. This study sought to understand the scope of existing health indicators, while aiming to discover new indicators for building resilience against three climate sensitive diseases (cerebro spinal meningitis, malaria and diarrhea). Therefore, new potential indicators derived from human and biophysical origins were developed to complement existing health indicators, thereby creating climate-sensitive battery of robust composite indices of resilience in health planning. Using Ghana's health sector as a case study systematic international literature review, national expert consultation, and focus group outcomes yielded insights into the relevance, sensitivity and impacts of 45 indicators in 11 categories in responding to climate change. In total, 65% of the indicators were sensitive to health impacts of climate change; 24% acted directly; 31% synergistically; and 45% indirectly, with indicator relevance strongly associated with type of health response. Epidemiological indicators (e.g. morbidity) and health demographic indicators (e.g. population structure) require adjustments with external indicators (e.g. biophysical, policy) to be resilient to climate change. Therefore, selective integration of social and ecological indicators with existing public health indicators improves the fidelity of the health sector to adopt more robust planning of interdependent systems to build resilience. The study highlights growing uncertainties in

  13. A Survey of the Relationship between Climatic Heat Stress Indices and Fundamental Milk Components Considering Uncertainty

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Marami Milani

    2015-11-01

    Full Text Available The main purpose of this study is to assess the relationship between four bioclimatic indices for cattle (environmental stress, heat load, modified heat load, and respiratory rate predictor indices and three main milk components (fat, protein, and milk yield considering uncertainty. The climate parameters used to calculate the climate indices were taken from the NASA-Modern Era Retrospective-Analysis for Research and Applications (NASA-MERRA reanalysis from 2002 to 2010. Cow milk data were considered for the same period from April to September when the cows use the natural pasture. The study is based on a linear regression analysis using correlations as a summarizing diagnostic. Bootstrapping is used to represent uncertainty information in the confidence intervals. The main results identify an interesting relationship between the milk compounds and climate indices under all climate conditions. During spring, there are reasonably high correlations between the fat and protein concentrations vs. the climate indices, whereas there are insignificant dependencies between the milk yield and climate indices. During summer, the correlation between the fat and protein concentrations with the climate indices decreased in comparison with the spring results, whereas the correlation for the milk yield increased. This methodology is suggested for studies investigating the impacts of climate variability/change on food and agriculture using short term data considering uncertainty.

  14. Using large-scale climate indices in climate change ecology studies

    DEFF Research Database (Denmark)

    Forchhammer, Mads Cedergreen; Post, Eric

    2004-01-01

    Ecological responses, El Niño 3.4, Long-term climate variability, North Atlantic Oscillation, North Pacific Oscillation, Teleconnection patterns......Ecological responses, El Niño 3.4, Long-term climate variability, North Atlantic Oscillation, North Pacific Oscillation, Teleconnection patterns...

  15. Using Visualization Science to Evaluate Effective Communication of Climate Indicators

    Science.gov (United States)

    Gerst, M.; Kenney, M. A.; Wolfinger, F.; Lloyd, A.

    2015-12-01

    Indicators are observations or calculations that are used to track social and environmental conditions over time. For a large coupled system such as the economy and environment, the choice of indicators requires a structured process that involves co-production among facilitators, subject-matter experts, decision-makers, and the general public. This co-production is needed in part because such indicators serve a duel role of scientifically tracking change and of communicating to non-scientists important changes and information that may be useful in decision contexts. Because the goal is to communicate and inform decisions it is critical that indicators be understood by non-scientific audiences, which may require different visualization techniques than for scientific audiences. Here we describe a process of rigorously evaluating visual communication efficacy by using a simplified taxonomy of visualization design problems and trade-offs to assess existing and redesigned indicator images. The experimental design is three-part. It involves testing non-scientific audiences' understandability of scientific images found in the literature along with similar information shaped by a partial co-production process that informed the U.S. Global Change Research Program prototype indicators system, released in Spring 2015. These recommendations for physical, natural, and societal indicators of changes and impacts involved input from over 200 subject-matter experts, organized into 13 technical teams. Using results from the first two parts, we then explore visualization design improvements that may increase understandability to non-scientific audiences. We anticipate that this work will highlight important trade-offs in visualization design when moving between audiences that will be of great use to scientists who wish to communicate their results broader audiences.

  16. An Indicator of the Impact of Climatic Change on European Bird Populations

    Science.gov (United States)

    Gregory, Richard D.; Willis, Stephen G.; Jiguet, Frédéric; Voříšek, Petr; Klvaňová, Alena; van Strien, Arco; Huntley, Brian; Collingham, Yvonne C.; Couvet, Denis; Green, Rhys E.

    2009-01-01

    Rapid climatic change poses a threat to global biodiversity. There is extensive evidence that recent climatic change has affected animal and plant populations, but no indicators exist that summarise impacts over many species and large areas. We use data on long-term population trends of European birds to develop such an indicator. We find a significant relationship between interspecific variation in population trend and the change in potential range extent between the late 20th and late 21st centuries, forecasted by climatic envelope models. Our indicator measures divergence in population trend between bird species predicted by climatic envelope models to be favourably affected by climatic change and those adversely affected. The indicator shows a rapid increase in the past twenty years, coinciding with a period of rapid warming. PMID:19259270

  17. Munchausen syndrome by proxy

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/001555.htm Munchausen syndrome by proxy To use the sharing features on this page, please enable JavaScript. Munchausen syndrome by proxy is a mental illness and ...

  18. Evaluating climate change mitigation potential of hydrochars: compounding insights from three different indicators

    DEFF Research Database (Denmark)

    Owsianiak, Mikołaj; Brooks, Jennifer; Renz, Michael

    2017-01-01

    beet, fava bean, onion and lucerne) and two different countries (Spain and Germany), and used three different indicators of climate change: global warming potential (GWP), global temperature change potential (GTP), and climate tipping potential (CTP). We found that although climate change benefits (GWP......) from just sequestration and temporary storage of carbon are sufficient to outweigh impacts stemming from hydrochar production and transportation to the field, even greater benefits stem from replacing climate-inefficient biowaste management treatment options, like composting in Spain. By contrast......-term climatic target, the tipping point corresponding to an atmospheric GHG concentration of 450 ppm CO2 equivalents, unless hydrochar stability in the soil is optimized. Our results highlight the need for considering complementary perspectives that different climate change indicators offer, and overall provide...

  19. Late nineteenth to early twenty-first century behavior of Alaskan glaciers as indicators of changing regional climate

    Science.gov (United States)

    Molnia, B.F.

    2007-01-01

    Alaska's climate is changing and one of the most significant indications of this change has been the late 19th to early 21st century behavior of Alaskan glaciers. Weather station temperature data document that air temperatures throughout Alaska have been increasing for many decades. Since the mid-20th century, the average change is an increase of ?????2.0????C. In order to determine the magnitude and pattern of response of glaciers to this regional climate change, a comprehensive analysis was made of the recent behavior of hundreds of glaciers located in the eleven Alaskan mountain ranges and three island areas that currently support glaciers. Data analyzed included maps, historical observations, thousands of ground-and-aerial photographs and satellite images, and vegetation proxy data. Results were synthesized to determine changes in length and area of individual glaciers. Alaskan ground photography dates from 1883, aerial photography dates from 1926, and satellite photography and imagery dates from the early 1960s. Unfortunately, very few Alaskan glaciers have any mass balance observations. In most areas analyzed, every glacier that descends below an elevation of ?????1500??m is currently thinning and/or retreating. Many glaciers have an uninterrupted history of continuous post-Little-Ice-Age retreat that spans more than 250??years. Others are characterized by multiple late 19th to early 21st century fluctuations. Today, retreating and/or thinning glaciers represent more than 98% of the glaciers examined. However, in the Coast Mountains, St. Elias Mountains, Chugach Mountains, and the Aleutian Range more than a dozen glaciers are currently advancing and thickening. Many currently advancing glaciers are or were formerly tidewater glaciers. Some of these glaciers have been expanding for more than two centuries. This presentation documents the post-Little-Ice-Age behavior and variability of the response of many Alaskan glaciers to changing regional climate. ?? 2006.

  20. The study of climate suitability for grapevine cropping using ecoclimatic indicators under climatic change conditions in France

    Science.gov (United States)

    Garcia de Cortazar-Atauri, I.; Caubel, J.; Cufi, J.; Huard, F.; Launay, M.; deNoblet, N.

    2013-12-01

    Climatic conditions play a fundamental role in the suitability of geographical areas for cropping. In the case of grape, climatic conditions such as water supply and temperatures have an effect of grape quality. In the context of climate change, we could expect changes in overall climatic conditions and so, in grape quality. We proposed to use GETARI (Generic Evaluation Tool of Ecoclimatic Indicators) in order to assess the future climate suitability of two French sites for grape (Vitis vinifera) regarding its quality. GETARI calculates an overall climate suitability index at the annual scale, from a designed evaluation tree. This aggregation tool proposes the major ecophysiological processes taking place during phenological periods, together with the climatic effects that are known to affect their achievement. The effects of climate on the ecophysiological processes are captured by the ecoclimatic indicators, which are agroclimatic indicators calculated over phenological periods. They give information about crop response to climate through ecophysiological or agronomic thresholds. These indicators are normalized and aggregated according to aggregation rules in order to compute an overall climate index. To assess the future climate suitability of two French sites for grape regarding its quality, we designed an evaluation tree from GETARI, by considering the effect of water deficit between flowering and veraison and the effect of water deficit, water excess, heat stress, temperature ranges between day and night, night temperatures and mean temperatures between veraison and harvest. The two sites are located in Burgundy and Rhone valley which are two of the most important vineyards in the world. Ecoclimatic indicators are calculated using phenological cycle of the crop. For this reason we chose Grenache and Pinot Noir as long and short cycle varieties respectively. Flowering, veraison and harvest dates were simulated (Parker et al., 2011; Yiou et al., 2012). Daily

  1. Climate index for Spain - Methodology; Indice climatique Espagne methodologie

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    According to the U.S. Department of Energy, an estimated 25% of the GNP is affected by weather-related events. The variations in temperature - even small ones - can also have long-lasting effects on the operational results of a company. Among other, the Energy supply sector is sensitive to weather risks: a milder or harsher than usual winter leads to a decrease or increase of energy consumption. The price of electricity on power trading facilities like Powernext is especially sensitive to odd changes in temperatures. Powernext and Meteo-France (the French meteorological agency) have joined expertise in order to promote the use of weather indices in term of decision making or underlying of hedging tools to energy actors, end users from any other sector of activity and specialists of the weather risk hedging. The Powernext Weather indices are made from information collected by Meteo-France's main observation network according to the norms of international meteorology, in areas carefully selected. The gross data are submitted to a thorough review allowing the correction of abnormalities and the reconstitution of missing data. Each index is fashioned to take into account the economic activity in the various regions of the country as represented by each region's population. This demographic information represents a fair approximation of the weight of the regional economic activity. This document presents the calculation methodology of average, minimum and maximum weather indexes with the winter and summer regression equations for the different economical regions of Spain. (J.S.)

  2. Climate index for Portugal - Methodology; Indices climatique Portugal methodologie

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    According to the U.S. Department of Energy, an estimated 25% of the GNP is affected by weather-related events. The variations in temperature - even small ones - can also have long-lasting effects on the operational results of a company. Among other, the Energy supply sector is sensitive to weather risks: a milder or harsher than usual winter leads to a decrease or increase of energy consumption. The price of electricity on power trading facilities like Powernext is especially sensitive to odd changes in temperatures. Powernext and Meteo-France (the French meteorological agency) have joined expertise in order to promote the use of weather indices in term of decision making or underlying of hedging tools to energy actors, end users from any other sector of activity and specialists of the weather risk hedging. The Powernext Weather indices are made from information collected by Meteo-France's main observation network according to the norms of international meteorology, in areas carefully selected. The gross data are submitted to a thorough review allowing the correction of abnormalities and the reconstitution of missing data. Each index is fashioned to take into account the economic activity in the various regions of the country as represented by each region's population. This demographic information represents a fair approximation of the weight of the regional economic activity. This document presents the calculation methodology of average, minimum and maximum weather indexes with the winter and summer regression equations for the different economical regions of Portugal. (J.S.)

  3. Life cycle and masting of a recovering keystone indicator species under climate fluctuation

    Science.gov (United States)

    Qinfeng Guo; Stanley J. Zarnoch; Xiongwen Chen; Dale G. Brockway

    2016-01-01

    Ecosystem health and sustainability, to a large degree, depend on the performance of keystone or dominant species. The role of climate on population dynamics of such species has been extensively examined, especially for health indicator species. Yet the life-cycle processes and response lags for many species could complicate efforts to detect clear climate signals....

  4. Lichen communities as climate indicators in the U.S. Pacific States.

    Science.gov (United States)

    Robert J. Smith; Sarah Jovan; Bruce. McCune

    2017-01-01

    Epiphytic lichens are bioindicators of climate, air quality, and other forest conditions and may reveal how forests will respond to global changes in the U.S. Pacific States of Alaska, Washington, Oregon, and California. We explored climate indication with lichen communities surveyed by using both the USDA Forest Service Forest Inventory and Analysis (FIA) and Alaska...

  5. Indicators of climate change in Idaho: An assessment framework for coupling biophysical change and social perception

    Science.gov (United States)

    Climate change is well documented at the global scale, but local and regional changes are not as well understood. Finer, local-to-regional scale information is needed for creating specific, place-based planning and adaption efforts. Here we detail the development of an indicator-focused climate chan...

  6. Decadal to millennial time scale climate variability in the Central Mediterranean during the Holocene: a reconstruction based on geochemical proxies from high resolution sedimentary records

    NARCIS (Netherlands)

    Goudeau, M.S.

    2014-01-01

    To assess potential anthropogenic contributions to future climate change it is necessary to understand natural climate variability. This can be achieved by studying climate variability during the Holocene, when similar basic climate boundary conditions persisted as today. During this period climate

  7. The influence of weather and climate on the reliability of magnetic properties of tree leaves as proxies for air pollution monitoring.

    Science.gov (United States)

    Rodríguez-Germade, Isabel; Mohamed, Kais Jacob; Rey, Daniel; Rubio, Belén; García, Alvaro

    2014-01-15

    Monthly monitoring of magnetic properties of Platanus hispanica tree leaves was used to assess atmospheric pollution in Madrid (Spain) and its suburban town of Pozuelo de Alarcón. Magnetic susceptibility, isothermal remanent magnetisation and metal concentrations were analysed to study the sources of atmospheric pollutants and their spatial and temporal evolution. In addition to urban dust, our results indicated that lithogenic dust and incorporation of trace metals in the leaf tissue also control the magnetic susceptibility of tree leaves. Global comparisons with cities of different climatic regimes suggest that air humidity is the key factor controlling the relative influence of pollutants, lithogenic dust and biological effects on the magnetic properties of tree leaves. Interaction of the atmosphere and tree leaves depends not only on local meteorology but also on climate. Climate, especially air humidity, and meteorology need to be considered when interpreting the magnetic properties of tree leaves as an atmospheric pollution tool. © 2013 Elsevier B.V. All rights reserved.

  8. Vulnerability of Agriculture to Climate Change as Revealed by Relationships between Simulated Crop Yield and Climate Change Indices

    Science.gov (United States)

    King, A. W.; Absar, S. M.; Nair, S.; Preston, B. L.

    2012-12-01

    The vulnerability of agriculture is among the leading concerns surrounding climate change. Agricultural production is influenced by drought and other extremes in weather and climate. In regions of subsistence farming, worst case reductions in yield lead to malnutrition and famine. Reduced surplus contributes to poverty in agrarian economies. In more economically diverse and industrialized regions, variations in agricultural yield can influence the regional economy through market mechanisms. The latter grows in importance as agriculture increasingly services the energy market in addition to markets for food and fiber. Agriculture is historically a highly adaptive enterprise and will respond to future changes in climate with a variety of adaptive mechanisms. Nonetheless, the risk, if not expectation, of increases in climate extremes and hazards exceeding historical experience motivates scientifically based anticipatory assessment of the vulnerability of agriculture to climate change. We investigate the sensitivity component of that vulnerability using EPIC, a well established field-scale model of cropping systems that includes the simulation of economic yield. The core of our analysis is the relationship between simulated yield and various indices of climate change, including the CCI/CLIVAR/JCOM ETCCDI indices, calculated from weather inputs to the model. We complement this core with analysis using the DSSAT cropping system model and exploration of relationships between historical yield statistics and climate indices calculated from weather records. Our analyses are for sites in the Southeast/Gulf Coast region of the United States. We do find "tight" monotonic relationships between annual yield and climate for some indices, especially those associated with available water. More commonly, however, we find an increase in the variability of yield as the index value becomes more extreme. Our findings contribute to understanding the sensitivity of crop yield as part of

  9. Development of Climate Indices Using Local Weather Data for Shading Design

    Directory of Open Access Journals (Sweden)

    Dong-Seok Lee

    2015-02-01

    Full Text Available The energy performance of buildings depends on how effectively the building envelope responds to climate. Architects, therefore, need to design building envelopes with the consideration of local climate characteristics in the early design stage. Simplified formulas were used that evaluate the heating and cooling energy demand of building envelopes, which were applied to a model building with envelope and climate properties according to eight climate zones. Two climate indices, P and S, were developed. P enables the comparison of the heating and cooling energy demand of building envelopes, and S is for comparing the solar heat gain during heating and cooling seasons to review the feasibility of installing shading devices. The physical properties of envelopes were set differently according to the requirements in each climate zone proposed by American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE 90.1. Using local climate data, the P and S of 24 cities over eight climate zones in the United States were derived, which can be used to evaluate the heating and cooling energy characteristics of envelopes. The indices not only enable users to understand the characteristics of the local climate conditions in a simple manner, but also to carry out quantitative assessments on whether shading devices are feasible and, if so, what type is recommended.

  10. Development of key indicators to quantify the health impacts of climate change on Canadians.

    Science.gov (United States)

    Cheng, June J; Berry, Peter

    2013-10-01

    This study aimed at developing a list of key human health indicators for quantifying the health impacts of climate change in Canada. A literature review was conducted in OVID Medline to identify health morbidity and mortality indicators currently used to quantify climate change impacts. Public health frameworks and other studies of climate change indicators were reviewed to identify criteria with which to evaluate the list of proposed key indicators and a rating scale was developed. Total scores for each indicator were calculated based on the rating scale. A total of 77 health indicators were identified from the literature. After evaluation using the chosen criteria, 8 indicators were identified as the best for use. They include excess daily all-cause mortality due to heat, premature deaths due to air pollution (ozone and particulate matter 2.5), preventable deaths from climate change, disability-adjusted life years lost from climate change, daily all-cause mortality, daily non-accidental mortality, West Nile Disease incidence, and Lyme borreliosis incidence. There is need for further data and research related to health effect quantification in the area of climate change.

  11. Regional climate change trends and uncertainty analysis using extreme indices: A case study of Hamilton, Canada

    National Research Council Canada - National Science Library

    Razavi, Tara; Switzman, Harris; Arain, Altaf; Coulibaly, Paulin

    2016-01-01

    .... Several different global climate models, downscaling methods, and emission scenarios were used to develop extreme temperature and precipitation indices at the local scale in the Hamilton region, Ontario, Canada...

  12. Regional climate model simulations indicate limited climatic impacts by operational and planned European wind farms.

    Science.gov (United States)

    Vautard, Robert; Thais, Françoise; Tobin, Isabelle; Bréon, François-Marie; Devezeaux de Lavergne, Jean-Guy; Colette, Augustin; Yiou, Pascal; Ruti, Paolo Michele

    2014-01-01

    The rapid development of wind energy has raised concerns about environmental impacts. Temperature changes are found in the vicinity of wind farms and previous simulations have suggested that large-scale wind farms could alter regional climate. However, assessments of the effects of realistic wind power development scenarios at the scale of a continent are missing. Here we simulate the impacts of current and near-future wind energy production according to European Union energy and climate policies. We use a regional climate model describing the interactions between turbines and the atmosphere, and find limited impacts. A statistically significant signal is only found in winter, with changes within ±0.3 °C and within 0-5% for precipitation. It results from the combination of local wind farm effects and changes due to a weak, but robust, anticyclonic-induced circulation over Europe. However, the impacts remain much weaker than the natural climate interannual variability and changes expected from greenhouse gas emissions.

  13. Multi-proxy sedimentary record from Lake Ghirla (N-Italy) reveals hydro-climatic variations and periods of anthropogenic activities during the past 13 kyrs

    Science.gov (United States)

    Wirth, Stefanie B.; Gilli, Adrian; Sessions, Alex L.

    2016-04-01

    humans from our data. The Roman Period (2.1-1.5 kyr BP) is characterized by elevated Pb concentrations (110 ppm). During the last millennium we find conspicuous spikes of Cu at 800 and 700 yr BP, probably due to mining activities, as well as elevated Pb concentrations at about 800, 400 (100 ppm) and after 50 yr BP (180 ppm). Arsenic shows high sedimentary concentrations of up to 500 ppm in the course of the past 13 kyrs. Elevated values seem to be related to periods with high detrital input due to floods as well as to intervals probably deposited under anoxic bottom-water conditions. Phases of elevated Cu and Pb concentrations show no relation with flood occurrence, which might indicate that human activities in the Lake Ghirla area were not importantly influenced by hydro-climatic variations. In conclusion, the sediments of Lake Ghirla offer a comprehensive archive for studying post-glacial climate, environmental changes and human activities.

  14. Large shifts in vegetation and climate during the Early Weichselian (MIS 5d-c) inferred from multi-proxy evidence at Sokli (northern Finland)

    NARCIS (Netherlands)

    Helmens, K.F.; Väliranta, M.; Engels, S.; Shala, S

    2012-01-01

    For decades, detailed studies on Early Weichselian deposits have been made in central Europe. In contrast, these studies are rare in Fennoscandia in northern Europe. We here integrate an extensive multi-proxy data set obtained on sediments of MIS 5d-c age that form part of a long sediment record

  15. A Multi-Component Proxy for OH Variability Measured from Space: Evaluation and Evolution

    Science.gov (United States)

    Murray, L. T.; Fiore, A. M.; Valin, L. C.

    2014-12-01

    Observed changes in the decay rate of methyl chloroform (MCF; CH3CCl3) have been the traditional top-down constraint for variability in tropospheric abundances of the hydroxyl radical (OH), and thereby the oxidative capacity of the atmosphere. However, as atmospheric MCF concentrations approach detection limits following its ban under the Montréal Protocol, it is necessary to identify new proxies for global OH and its variability. We present here a novel proxy for tropospheric OH using convolved observations of total and tropospheric columns of ozone, water vapor, NO2, and CO, available from the Aura and Aqua satellites in the NASA Earth Observing System constellation. Derived from photochemical steady-state assumptions, the satellite proxy generates spatiotemporally coherent monthly percent anomalies in column OH for Oct. 2004 through Sept. 2012. We demonstrate that the temporal evolution of the globally integrated signal is statistically consistent with changes inferred by the MCF decay rate during this period. The magnitude of interannual variability in the satellite OH proxy is smaller than that from MCF, more consistent with global chemical transport models (CTMs). We evaluate the proxy by comparing to 9-year hind-cast simulations of the GEOS-Chem global CTM driven by MERRA reanalysis meteorology at 2° x 2.5° horizontal resolution, and find that the satellite proxy correlates with the airmass-weighted tropospheric monthly mean OH anomalies (R = 0.6; n = 96 months). The satellite proxy and model simulations indicate regional-scale coherent OH anomalies for many regions and seasons; where discrepancies occur, we highlight possible causes. We present a source attribution of the spatial and temporal patterns in the satellite OH proxy, informed by the individual components of the satellite proxy, a series of zero-emission sensitivity simulations with GEOS-Chem, and independent proxies for major modes of climate variability.

  16. Geochemical and stable isotope indicators of paleoenvironmental and climatic conditions from Cenozoic dolocretes in the Hamersley Basin of northwest Australia

    Science.gov (United States)

    Mather, Caroline; Skrzypek, Grzegorz; Dogramaci, Shawan; Grierson, Pauline

    2017-04-01

    Extensive shallow groundwater carbonate deposits composed of dolomite (dolocretes) are ubiquitous within the semi-arid Hamersley Basin of NW Australia. However, dolomite is relatively rare within surficial terrestrial carbonate deposits as precipitation is strongly controlled by reaction kinetics and is inhibited at surface temperatures and pressures. The presence of dolomite within the Hamersley Basin carbonate deposits indicates that specific hydrochemical conditions occurred to overcome kinetic barriers to precipitation, namely elevated Mg/Ca and high salinity and alkalinity. We investigated the sedimentology, geochemistry and stable isotope compositions of dolocrete and groundwater chemistry from several locations in the Hamersley Basin to better understand dolocrete formation processes and produce a multi-proxy archive of the paleoenvironmental conditions. Petrographic and mineralogical analysis is consistent with channel dolocrete formation where dolomite has largely replaced host channel sediments. Authigenic palygorskite was also present in all samples, indicative of the Mg-rich environment. Modelling of the δ18O of paleogroundwater from oxygen isotope compositions of carbonates revealed dolomite precipitated from groundwater with considerably higher δ18O (median = -2.0‰) values compared to modern alluvial groundwater (-8.02 ± 0.83‰). As groundwater δ18O values are strongly correlated (R2=0.93) with salinity, this finding suggests that dolocrete formed from highly saline groundwaters and in an arid climate that prevailed for sufficient time to form dolocrete bodies of tens of metres thick. This ancient dolocrete formation can be constrained by host sediments ages to forming since the mid-late Miocene. In contrast, modern alluvial groundwater is relatively fresh and unlikely to precipitate dolomite. A further indication of a more recent (likely Holocene) shift to fresher waters is the dedolomitization and precipitation of calcite within shallow

  17. A multi-hazard regional level impact assessment for Europe combining indicators of climatic and non-climatic change

    NARCIS (Netherlands)

    Lung, T.; Lavalle, C.; Hiederer, R.; Dosio, A.; Bouwer, L.M.

    2013-01-01

    To better prioritise adaptation strategies to a changing climate that are currently being developed, there is a need for quantitative regional level assessments that are systematic and comparable across multiple weather hazards. This study presents an indicator-based impact assessment framework at

  18. A multi-proxy record from the Quaternary Vienna Basin: Chronology, climate and environmental change at the Alpine-Carpathian transition during the last 250,000 years

    Science.gov (United States)

    Salcher, Bernhard; Lomax, Johanna; Frank, Christa; Preusser, Frank; Scholger, Robert; Ottner, Franz; Wagreich, Michael

    2016-04-01

    Dated multi-proxy records of terrestrial sequences in the Quaternary of the circum-Alpine realm are sparse. This is especially true for those exceeding the time span of the last glacial maximum as extensive glaciers eroded substantial parts of potential records. Outside formerly glaciated regions, preservation space is low in the absence of tectonic subsidence. Foreland terraces forming as a consequence of mountain range uplift may partly account for this gap but are typically dominated by coarse-grained fluvial sediments commonly reflecting only short pulses during cold stage periods. Here we analyze a terrestrial record in the Vienna Basin in order to derive regional climatic and environmental changes of the last c. 250 ka. The Vienna Basin forms as a classical pull-apart feature showing a length of almost 200 km and a width of c. 55 km. Quaternary subsidence is focused along the active Vienna Basin Transfer Fault leading to the formation of a series of narrow strike-slip (sub-) basins and grabens with the Mitterndorf sub-basin being the largest (c. 270 km²) and deepest (c.175 m). The southern part of the basin is confined by the alpine mountain front and fed by two alluvial fans highlighting up to several tens of meters thick coarse grained, massive sediments intercalated by up to few meters thick fine clastic sediments. We investigated the fan's sequence development through core and outcrop sampling applying luminescence dating, magnetostratigraphy, soil and lithofacies classification as well as malacological analysis. The latter comprise the determination and distribution of species and individuals as well as coenological analysis. Data suggest a distinct sequence development with coarse-grained massive sediments abundantly deposited during cold periods (MIS 2 and 6) and fine, overbank sediments and soils, dominantly forming during warmer, Interstadial or Interglacial periods (MIS 5 and 7). Overbanks and soils are generally rich in terrestrial mollusk

  19. Are fish outside their usual ranges early indicators of climate-driven range shifts?

    Science.gov (United States)

    Fogarty, Hannah E; Burrows, Michael T; Pecl, Gretta T; Robinson, Lucy M; Poloczanska, Elvira S

    2017-05-01

    Shifts in species ranges are a global phenomenon, well known to occur in response to a changing climate. New species arriving in an area may become pest species, modify ecosystem structure, or represent challenges or opportunities for fisheries and recreation. Early detection of range shifts and prompt implementation of any appropriate management strategies is therefore crucial. This study investigates whether 'first sightings' of marine species outside their normal ranges could provide an early warning of impending climate-driven range shifts. We examine the relationships between first sightings and marine regions defined by patterns of local climate velocities (calculated on a 50-year timescale), while also considering the distribution of observational effort (i.e. number of sampling days recorded with biological observations in global databases). The marine trajectory regions include climate 'source' regions (areas lacking connections to warmer areas), 'corridor' regions (areas where moving isotherms converge), and 'sink' regions (areas where isotherms locally disappear). Additionally, we investigate the latitudinal band in which first sightings were recorded, and species' thermal affiliations. We found that first sightings are more likely to occur in climate sink and 'divergent' regions (areas where many rapid and diverging climate trajectories pass through) indicating a role of temperature in driving changes in marine species distributions. The majority of our fish first sightings appear to be tropical and subtropical species moving towards high latitudes, as would be expected in climate warming. Our results indicate that first sightings are likely related to longer-term climatic processes, and therefore have potential use to indicate likely climate-driven range shifts. The development of an approach to detect impending range shifts at an early stage will allow resource managers and researchers to better manage opportunities resulting from range

  20. Natural climate variability as indicated by glaciers and implications for climate change: a modeling study

    Energy Technology Data Exchange (ETDEWEB)

    Reichert, B.K. [Columbia Univ., Palisades, NY (United States). Lamont-Doherty Earth Observatory; Bengtsson, L. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Oerlemans, J. [Rijksuniversiteit Utrecht (Netherlands). Inst. for Marine and Atmospheric Research

    2001-08-01

    Glacier fluctuations exclusively due to internal variations in the climate system are simulated using downscaled integrations of the ECHAM4/OPYC coupled general circulation model (GCM). A process-based modeling approach using a mass balance model of intermediate complexity and a dynamic ice flow model considering simple shearing flow and sliding are applied. Multi-millennia records of glacier length fluctuations for Nigardsbreen (Norway) and Rhonegletscher (Switzerland) are simulated using auto-regressive processes determined by statistically downscaled GCM experiments. Return periods and probabilities of specific glacier length changes using GCM integrations excluding external forcings such as solar irradiation changes, volcanic or anthropogenic effects are analyzed and compared to historical glacier length records. Preindustrial fluctuations of the glaciers as far as observed or reconstructed, including their advance during the ''Little Ice Age'', can be explained by internal variability in the climate system as represented by a GCM. However, fluctuations comparable to the present-day glacier retreat do not occur in the GCM control experiments and must be caused by external forcing, with anthropogenic forcing being a likely candidate. (orig.)

  1. Holocene glacier fluctuations in the Peruvian Andes indicate northern climate linkages.

    Science.gov (United States)

    Licciardi, Joseph M; Schaefer, Joerg M; Taggart, Jean R; Lund, David C

    2009-09-25

    The role of the tropics in triggering, transmitting, and amplifying interhemispheric climate signals remains a key debate in paleoclimatology. Tropical glacier fluctuations provide important insight on regional paleoclimatic trends and forcings, but robust chronologies are scarce. Here, we report precise moraine ages from the Cordillera Vilcabamba (13 degrees 20'S) of southern Peru that indicate prominent glacial events and associated climatic shifts in the outer tropics during the early Holocene and late in the "Little Ice Age" period. Our glacier chronologies differ from the New Zealand record but are broadly correlative with well-dated glacial records in Europe, suggesting climate linkages between the tropics and the North Atlantic region.

  2. An Approach to Developing Local Climate Change Environmental Public Health Indicators in a Rural District.

    Science.gov (United States)

    Houghton, Adele; Austin, Jessica; Beerman, Abby; Horton, Clayton

    2017-01-01

    Climate change represents a significant and growing threat to population health. Rural areas face unique challenges, such as high rates of vulnerable populations; economic uncertainty due to their reliance on industries that are vulnerable to climate change; less resilient infrastructure; and lower levels of access to community and emergency services than urban areas. This article fills a gap in public health practice by developing climate and health environmental public health indicators for a local public health department in a rural area. We adapted the National Environmental Public Health Tracking Network's framework for climate and health indicators to a seven-county health department in Western Kentucky. Using a three-step review process, we identified primary climate-related environmental public health hazards for the region (extreme heat, drought, and flooding) and a suite of related exposure, health outcome, population vulnerability, and environmental vulnerability indicators. Indicators that performed more poorly at the county level than at the state and national level were defined as "high vulnerability." Six to eight high vulnerability indicators were identified for each county. The local health department plans to use the results to enhance three key areas of existing services: epidemiology, public health preparedness, and community health assessment.

  3. Precipitation extremes and their relation to climatic indices in the Pacific Northwest USA

    Science.gov (United States)

    Zarekarizi, Mahkameh; Rana, Arun; Moradkhani, Hamid

    2017-09-01

    There has been focus on the influence of climate indices on precipitation extremes in the literature. Current study presents the evaluation of the precipitation-based extremes in Columbia River Basin (CRB) in the Pacific Northwest USA. We first analyzed the precipitation-based extremes using statistically (ten GCMs) and dynamically downscaled (three GCMs) past and future climate projections. Seven precipitation-based indices that help inform about the flood duration/intensity are used. These indices help in attaining first-hand information on spatial and temporal scales for different service sectors including energy, agriculture, forestry etc. Evaluation of these indices is first performed in historical period (1971-2000) followed by analysis of their relation to large scale tele-connections. Further we mapped these indices over the area to evaluate the spatial variation of past and future extremes in downscaled and observational data. The analysis shows that high values of extreme indices are clustered in either western or northern parts of the basin for historical period whereas the northern part is experiencing higher degree of change in the indices for future scenario. The focus is also on evaluating the relation of these extreme indices to climate tele-connections in historical period to understand their relationship with extremes over CRB. Various climate indices are evaluated for their relationship using Principal Component Analysis (PCA) and Singular Value Decomposition (SVD). Results indicated that, out of 13 climate tele-connections used in the study, CRB is being most affected inversely by East Pacific (EP), Western Pacific (WP), East Atlantic (EA) and North Atlaentic Oscillation (NAO).

  4. Jemen - the Proxy War

    Directory of Open Access Journals (Sweden)

    Magdalena El Ghamari

    2015-12-01

    Full Text Available The military operation in Yemen is significant departure from Saudi Arabia's foreign policy tradition and customs. Riyadh has always relied on three strategies to pursue its interests abroad: wealth, establish a global network and muslim education and diplomacy and meadiation. The term "proxy war" has experienced a new popularity in stories on the Middle East. A proxy war is two opposing countries avoiding direct war, and instead supporting combatants that serve their interests. In some occasions, one country is a direct combatant whilst the other supporting its enemy. Various news sources began using the term to describe the conflict in Yemen immediately, as if on cue, after Saudi Arabia launched its bombing campaign against Houthi targets in Yemen on 25 March 2015. This is the reason, why author try to answer for following questions: Is the Yemen Conflict Devolves into Proxy War? and Who's fighting whom in Yemen's proxy war?" Research area includes the problem of proxy war in the Middle East. For sure, the real problem of proxy war must begin with the fact that the United States and its NATO allies opened the floodgates for regional proxy wars by the two major wars for regime change: in Iraq and Libya. Those two destabilising wars provided opportunities and motives for Sunni states across the Middle East to pursue their own sectarian and political power objectives through "proxy war".

  5. Flood-induced agricultural loss across China and impacts from climate indices

    Science.gov (United States)

    Zhang, Qiang; Gu, Xihui; Singh, Vijay P.; Liu, Lin; Kong, Dongdong

    2016-04-01

    Province-wide data on flood-destroyed and flood-affected crop areas across China covering a period of 1960-2013 were analyzed in this study for investigating their relations with climate indices, such as ENSO, NAO, IOD, PDO and AMO. Results indicated that: (1) agricultural flooding in northeast and south China tended to enhance under the influence of warm PDO and warm IOD events of the previous years. However, agricultural flooding in southwest China tended to decrease as a result of warm ENSO events of the previous years. Agricultural floods in coastal regions of southeast China were influenced by more than one climate index; (2) Agricultural floods of different time scales were subject to different degrees of correlations with climate indices. Remarkably, climate indices that were significantly correlated with agricultural floods were usually temporally enhancing. Relations between ENSO and agricultural floods across China were statistically strong with good persistency. Thus, ENSO can be taken as a suitable predictor for flood-affected and flood-destroyed crop areas across China. However, AMO cannot be taken as the predictor for flood-affected and flood-destroyed crop areas in China; (3) The combined influence of climate indices on flood-affected and flood-destroyed crop areas across China did not have a firm spatiotemporal pattern. However, specific groups of climate indices can have definitive impacts on flood-affected and flood-destroyed crop areas over specific regions. Findings of this study can help predict flood-affected and flood-destroyed crop areas across provinces of China, and hence plan and manage agricultural activities in China.

  6. A Tale of Two Limpets (Patella vulgata and Patella stellaeformis): Evaluating a New Proxy for Late Holocene Climate Change in Coastal Areas

    Science.gov (United States)

    Fenger, T. L.; Surge, D. M.; Schoene, B. R.; Carter, J. G.; Milner, N.

    2006-12-01

    Shells of the European limpet, Patella vulgata, from Late Holocene archaeological deposits potentially contain critical information about climate change in coastal areas. Before deciphering climate information preserved in these zooarchaeological records, we studied the controls on oxygen isotope ratios (δ18O) in modern specimens. We tested the hypothesis that P. vulgata precipitates its shell in isotopic equilibrium with ambient water by comparing δ18OSHELL with expected values. Expected δ18OSHELL was constructed using the calcite-water fractionation equation, observed sea surface temperature (SST), and assuming δ18OWATER is +0.10‰ (VSMOW). Comparison between expected and measured δ18OSHELL revealed a +1.51±0.21‰ (VPDB) offset from expected values. Consequently, estimated SST calculated from δ18OSHELL was 6.50±2.45°C lower than observed SST. However, because the offset was relatively uniform, an adjustment can be made to account for this predictable vital effect and past SST can be reliably reconstructed. To further investigate the source of offset in this genus, we analyzed a fully marine tropical species (Patella stellaeformis) to minimize seasonal variation in environmental factors that influence δ18OSHELL. P. stellaeformis was evaluated to determine whether it has a similar offset from equilibrium as P. vulgata. We tested the hypotheses that: (1) δ18OSHELL in tropical species also displays vital effects; and (2) the offset from equilibrium (if any) would be constant and predictable. Our results indicated: (1) aragonite comprises most of P. stellaeformis' shell; and (2) δ18OSHELL is statistically indistinguishable from expected values calculated using the aragonite-water fractionation equation (Kolmogorov-Smirnov test statistic=0.61, D0.05[56, 57]=1.36) in contrast with our observations in P. vulgata. Differences in mineralogy or growth rates at different latitudes may play a role in mechanisms that influence vital effects.

  7. A Review of Frameworks for Developing Environmental Health Indicators for Climate Change and Health

    Science.gov (United States)

    Hambling, Tammy; Weinstein, Philip; Slaney, David

    2011-01-01

    The role climate change may play in altering human health, particularly in the emergence and spread of diseases, is an evolving area of research. It is important to understand this relationship because it will compound the already significant burden of diseases on national economies and public health. Authorities need to be able to assess, anticipate, and monitor human health vulnerability to climate change, in order to plan for, or implement action to avoid these eventualities. Environmental health indicators (EHIs) provide a tool to assess, monitor, and quantify human health vulnerability, to aid in the design and targeting of interventions, and measure the effectiveness of climate change adaptation and mitigation activities. Our aim was to identify the most suitable framework for developing EHIs to measure and monitor the impacts of climate change on human health and inform the development of interventions. Using published literature we reviewed the attributes of 11 frameworks. We identified the Driving force-Pressure-State-Exposure-Effect-Action (DPSEEA) framework as the most suitable one for developing EHIs for climate change and health. We propose the use of EHIs as a valuable tool to assess, quantify, and monitor human health vulnerability, design and target interventions, and measure the effectiveness of climate change adaptation and mitigation activities. In this paper, we lay the groundwork for the future development of EHIs as a multidisciplinary approach to link existing environmental and epidemiological data and networks. Analysis of such data will contribute to an enhanced understanding of the relationship between climate change and human health. PMID:21845162

  8. Developing Health-Related Indicators of Climate Change: Australian Stakeholder Perspectives.

    Science.gov (United States)

    Navi, Maryam; Hansen, Alana; Nitschke, Monika; Hanson-Easey, Scott; Pisaniello, Dino

    2017-05-22

    Climate-related health indicators are potentially useful for tracking and predicting the adverse public health effects of climate change, identifying vulnerable populations, and monitoring interventions. However, there is a need to understand stakeholders' perspectives on the identification, development, and utility of such indicators. A qualitative approach was used, comprising semi-structured interviews with key informants and service providers from government and non-government stakeholder organizations in South Australia. Stakeholders saw a need for indicators that could enable the monitoring of health impacts and time trends, vulnerability to climate change, and those which could also be used as communication tools. Four key criteria for utility were identified, namely robust and credible indicators, specificity, data availability, and being able to be spatially represented. The variability of risk factors in different regions, lack of resources, and data and methodological issues were identified as the main barriers to indicator development. This study demonstrates a high level of stakeholder awareness of the health impacts of climate change, and the need for indicators that can inform policy makers regarding interventions.

  9. Regionalizing indicators for marine ecosystems: Bering Sea–Aleutian Island seabirds, climate, and competitors

    Science.gov (United States)

    Sydeman, William J.; Thompson, Sarah Ann; Piatt, John F.; García-Reyes, Marisol; Zador, Stephani; Williams, Jeffrey C.; Romano, Marc; Renner, Heather

    2017-01-01

    Seabirds are thought to be reliable, real-time indicators of forage fish availability and the climatic and biotic factors affecting pelagic food webs in marine ecosystems. In this study, we tested the hypothesis that temporal trends and interannual variability in seabird indicators reflect simultaneously occurring bottom-up (climatic) and competitor (pink salmon) forcing of food webs. To test this hypothesis, we derived multivariate seabird indicators for the Bering Sea–Aleutian Island (BSAI) ecosystem and related them to physical and biological conditions known to affect pelagic food webs in the ecosystem. We examined covariance in the breeding biology of congeneric pelagic gulls (kittiwakes Rissa tridactyla and R. brevirostris) andauks (murres Uria aalge and U. lomvia), all of whichare abundant and well-studiedinthe BSAI. At the large ecosystem scale, kittiwake and murre breeding success and phenology (hatch dates) covaried among congeners, so data could be combined using multivariate techniques, but patterns of responsedifferedsubstantially betweenthe genera.Whiledata fromall sites (n = 5)inthe ecosystemcould be combined, the south eastern Bering Sea shelf colonies (St. George, St. Paul, and Cape Peirce) provided the strongest loadings on indicators, and hence had the strongest influence on modes of variability. The kittiwake breeding success mode of variability, dominated by biennial variation, was significantly related to both climatic factors and potential competitor interactions. The murre indicator mode was interannual and only weakly related to the climatic factors measured. The kittiwake phenology indicator mode of variability showed multi-year periods (“stanzas”) of late or early breeding, while the murre phenology indicator showed a trend towards earlier timing. Ocean climate relationships with the kittiwake breeding success indicator suggestthat early-season (winter–spring) environmental conditions and the abundance of pink salmon affect the

  10. Statistical framework for evaluation of climate model simulations by use of climate proxy data from the last millennium -- Part 3: Practical considerations, relaxed assumptions, and using tree-ring data to address the amplitude of solar forcing

    National Research Council Canada - National Science Library

    Moberg, A; Sundberg, R; Grudd, H; Hind, A

    2015-01-01

    ... the observations significantly better than the other. The extended framework is applied to a set of simulations driven with forcings for the pre-industrial period 1000-1849 CE and 15 tree-ring-based temperature proxy series...

  11. Transitional properties of droughts and related impacts of climate indices in the Pearl River basin, China

    Science.gov (United States)

    Xiao, Mingzhong; Zhang, Qiang; Singh, Vijay P.; Liu, Lin

    2016-03-01

    Drought is the natural hazard poorly understood so far due to various mechanisms behind. Moreover, disastrous effects of drought on human society necessitate accurate forecasting of drought behaviors. In this case, to improve forecasting of drought in the Pearl River basin, a trivariate copula model has been developed and used to include the El Nino Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Indian Ocean Dipole (IOD) and Pacific Decadal Oscillation (PDO) into model structure of Markov chain. The Standardized Precipitation Evapotranspiration Index (SPEI) has been used to monitor the drought in this study. Comparison with the preliminary correlation analysis between each month climate index and SPEI series indicated that the trivariate copula performs satisfactorily well in evaluation of influences of climate indices on the transition probabilities of drought. It is considered that the region with the negative vertical velocity is dominated by more precipitation and vice versa. Moreover, field patterns of 500 hPa vertical velocity anomalies related to each climate index have further corroborated the influences of climate indices on the drought behaviors. Besides, the mean extreme drought durations under different conditions of each climate index have also been investigated in this study. Results indicated that the mean extreme drought duration tends to be longer in the western part of the Pearl River basin during positive phase of ENSO while tends to be shorter during the positive phase of NAO and vice versa; in the central part of the Pearl River basin, the mean extreme drought duration tends to be shorter during the positive phase of ENSO, NAO and PDO while tends to be longer during the positive episode of IOD, and vice versa; in the eastern part of the Pearl River basin, the mean extreme drought duration tends to be shorter during the positive episode of ENSO and PDO, and vice versa. This study sheds new light on transitional behaviors of

  12. Spatiotemporal monthly rainfall forecasts for south-eastern and eastern Australia using climatic indices

    Science.gov (United States)

    Montazerolghaem, Maryam; Vervoort, Willem; Minasny, Budiman; McBratney, Alex

    2016-05-01

    Knowledge about future rainfall is important for agriculture management and planning in arid and semi-arid regions. Australia has complex variations in rainfall patterns in time and space, arising from the combination of the geographic structure and the dual effects of Indian and Pacific Ocean. This study aims to develop a forecasting model of spatiotemporal monthly rainfall totals using lagged climate indices and historical rainfall data from 1950-2011 for south-eastern and eastern Australia. Data were obtained from the Australian Bureau of Meteorology (BoM) from 136 high-quality weather stations. To reduce spatial complexity, climate regionalization was used to divide the stations in homogenous sub-regions based on similarity of rainfall patterns and intensity using principal component analysis (PCA) and K-means clustering. Subsequently, a fuzzy ranking algorithm (FRA) was applied to the lagged climatic predictors and monthly rainfall in each sub-region to identify the best predictors. Selected predictors by FRA were found to vary by sub-region. After these two stages of pre-processing, an artificial neural network (ANN) model was developed and optimized separately for each sub-region and the entire area. The results indicate that climate regionalization can improve a monthly spatiotemporal rainfall forecast model. The location and number of sub-regions were important for ranking predictors and modeling. This further suggests that the impact of climate variables on Australian rainfall is more variable in both time and space than indicated thus far.

  13. SINOMA - a better tool for proxy based reconstructions?

    Science.gov (United States)

    Buras, Allan; Thees, Barnim; Czymzik, Markus; Dräger, Nadine; Kienel, Ulrike; Neugebauer, Ina; Ott, Florian; Scharnweber, Tobias; Simard, Sonia; Slowinski, Michal; Slowinski, Sandra; Tecklenburg, Christina; Zawiska, Izabela; Wilmking, Martin

    2014-05-01

    than on its mathematical background which we intend to present in another contribution to this EGU session (Thees at al., 2014). On average, SINOMA performs better than or, under specific error noise conditions, equal to the traditional modeling techniques. However, some of the investigated data reveal constraints of SINOMA, which have to be considered in 'real-world' applications. Nevertheless, our results indicate that SINOMA likely is a more reliable tool for estimating regression parameters if compared to traditional techniques. Based on the generally noisy characteristics of proxies used typically, applications of SINOMA to already existing reconstructions will probably result in different model parameter estimates, most likely leading to differing amplitudes of reconstructed past environmental conditions. Therefore, SINOMA has the potential to reframe our picture of the past. References: Kutzbach L, Thees B, and Wilmking M (2011): Identification of linear relationships from noisy data using errors-in-variables models -relevance for reconstruction of past climate from tree-ring and other proxy information, Climatic Change, 105, 155-177. Thees B, Kutzbach L, Wilmking M, and Zorita E (2009): Ein Bewertungsmaß für die amplitudentreue regressive Abbildung von verrauschten Daten im Rahmen einer iterativen "Errors in Variables"- Modellierung (EVM), GKSS-report 2009/8. Thees B, Buras A, Jetschke G, Zorita E, Wilmking M, and Kutzbach L: The Sequential Iterative Noise Matching Algorithm: A new statistical approach for the unbiased estimation of linear relationships between noisy serial data streams and their respective error variances. Submitted. Thees B, Buras A, Jetschke G, Kutzbach L, Zorita, E, and Wilmking, M, 2014: SINOMA - A new iterative statistical approach for the identification of linear relationships between noisy time series. Abstract submitted to EGU-session CL 6.1.

  14. A Prototype Indicators System for U.S. Climate Changes, Impacts, Vulnerabilities, and Responses

    Science.gov (United States)

    Kenney, M. A.; Janetos, A.; Gerst, M.; Lloyd, A.; Wolfinger, J. F.; Reyes, J. J.; Anderson, S. M.; Pouyat, R. V.

    2015-12-01

    Indicators are observations or calculations that are used to systematically report or forecast social and biophysical conditions over time. When the purpose of indicators is to, in part, provide complex scientific information that is understood by non-scientists and included in decision processes, the choice of indicators requires a structured process that includes co-production among a range of actors, including scientists, decision-makers, and a range of stakeholders. Here we describe recommendations on a vision and a prototype created for an indicators system, we term the National Climate Indicators System (NCIS). The goal of the NCIS is to create a system of physical, natural, and societal indicators to communicate and inform decisions about climate changes, impacts, vulnerabilities, and responses. The process of generating the indicator system involved input from over 200 subject-matter experts. Organized into 13 teams, experts created conceptual models of their respective sectors to generate an initial recommended set of indicators. A subset of indicators, which could be immediately implemented, were prototyped for the U.S. Global Change Research Program (USGCRP) a Federal program that coordinates and supports integration of global change research across the government. USGCRP reviewed the recommendations (Kenney et al., 2014) and prototypes provided by the scientific experts, and recently launched 14 indicators as proof-of-concept in support of a sustained National Climate Assessment and to solicit feedback from the users. Social science research is currently being undertaken in order to evaluate how well the prototype indicators communicate science to non-scientists, the usability of indicator system portal by scientists and decision-makers, and the development of information visualization guidelines to improve visual communication effectiveness. The goal of such efforts would be to provide input into the development of a more comprehensive USGCRP indicator

  15. The Use of Geographically Weighted Regression for the Relationship among Extreme Climate Indices in China

    Directory of Open Access Journals (Sweden)

    Chunhong Wang

    2012-01-01

    Full Text Available The changing frequency of extreme climate events generally has profound impacts on our living environment and decision-makers. Based on the daily temperature and precipitation data collected from 753 stations in China during 1961–2005, the geographically weighted regression (GWR model is used to investigate the relationship between the index of frequency of extreme precipitation (FEP and other climate extreme indices including frequency of warm days (FWD, frequency of warm nights (FWN, frequency of cold days (FCD, and frequency of cold nights (FCN. Assisted by some statistical tests, it is found that the regression relationship has significant spatial nonstationarity and the influence of each explanatory variable (namely, FWD, FWN, FCD, and FCN on FEP also exhibits significant spatial inconsistency. Furthermore, some meaningful regional characteristics for the relationship between the studied extreme climate indices are obtained.

  16. Soil color indicates carbon and wetlands: developing a color-proxy for soil organic carbon and wetland boundaries on sandy coastal plains in South Africa.

    Science.gov (United States)

    Pretorius, M L; Van Huyssteen, C W; Brown, L R

    2017-10-13

    A relationship between soil organic carbon and soil color is acknowledged-albeit not a direct one. Since heightened carbon contents can be an indicator of wetlands, a quantifiable relationship between color and carbon might assist in determining wetland boundaries by rapid, field-based appraisal. The overarching aim of this initial study was to determine the potential of top soil color to indicate soil organic carbon, and by extension wetland boundaries, on a sandy coastal plain in South Africa. Data were collected from four wetland types in northern KwaZulu-Natal in South Africa. Soil samples were taken to a depth of 300 mm in three transects in each wetland type and analyzed for soil organic carbon. The matrix color was described using a Munsell soil color chart. Various color indices were correlated with soil organic carbon. The relationship between color and carbon were further elucidated using segmented quantile regression. This showed that potentially maximal carbon contents will occur at values of low color indices, and predictably minimal carbon contents will occur at values of low or high color indices. Threshold values can thus be used to make deductions such as "when the sum of dry and wet Value and Chroma values is 9 or more, carbon content will be 4.79% and less." These threshold values can then be used to differentiate between wetland and non-wetland sites with a 70 to 100% certainty. This study successfully developed a quantifiable correlation between color and carbon and showed that wetland boundaries can be determined based thereon.

  17. Post-processing Seasonal Precipitation Forecasts via Integrating Climate Indices and the Analog Approach

    Science.gov (United States)

    Liu, Y.; Zhang, Y.; Wood, A.; Lee, H. S.; Wu, L.; Schaake, J. C.

    2016-12-01

    Seasonal precipitation forecasts are a primary driver for seasonal streamflow prediction that is critical for a range of water resources applications, such as reservoir operations and drought management. However, it is well known that seasonal precipitation forecasts from climate models are often biased and also too coarse in spatial resolution for hydrologic applications. Therefore, post-processing procedures such as downscaling and bias correction are often needed. In this presentation, we discuss results from a recent study that applies a two-step methodology to downscale and correct the ensemble mean precipitation forecasts from the Climate Forecast System (CFS). First, CFS forecasts are downscaled and bias corrected using monthly reforecast analogs: we identify past precipitation forecasts that are similar to the current forecast, and then use the finer-scale observational analysis fields from the corresponding dates to represent the post-processed ensemble forecasts. Second, we construct the posterior distribution of forecast precipitation from the post-processed ensemble by integrating climate indices: a correlation analysis is performed to identify dominant climate indices for the study region, which are then used to weight the analysis analogs selected in the first step using a Bayesian approach. The methodology is applied to the California Nevada River Forecast Center (CNRFC) and the Middle Atlantic River Forecast Center (MARFC) regions for 1982-2015, using the North American Land Data Assimilation System (NLDAS-2) precipitation as the analysis. The results from cross validation show that the post-processed CFS precipitation forecast are considerably more skillful than the raw CFS with the analog approach only. Integrating climate indices can further improve the skill if the number of ensemble members considered is large enough; however, the improvement is generally limited to the first couple of months when compared against climatology. Impacts of

  18. A comparison and appraisal of a comprehensive range of human thermal climate indices.

    Science.gov (United States)

    de Freitas, C R; Grigorieva, E A

    2017-03-01

    Numerous human thermal climate indices have been proposed. It is a manifestation of the perceived importance of the thermal environment within the scientific community and a desire to quantify it. Schemes used differ in approach according to the number of variables taken into account, the rationale employed, and the particular design for application. They also vary considerably in type and quality, method used to express output, as well as in several other aspects. In light of this, a three-stage project was undertaken to deliver a comprehensive documentation, classification, and overall evaluation of the full range of existing human thermal climate indices. The first stage of the project produced a comprehensive register of as many thermal indices as could be found, 165 in all. The second stage devised a sorting scheme of these human thermal climate indices that grouped them according to eight primary classification categories. This, the third stage of the project, evaluates the indices. Six evaluation criteria, namely validity, usability, transparency, sophistication, completeness, and scope, are used collectively as evaluation criteria to rate each index scheme. The evaluation criteria are used to assign a score that varies between 1 and 5, 5 being the highest. The indices with the highest in each of the eight primary classification categories are discussed. The work is the final stage of a study of the all human thermal climatic indices that could be found in literature. Others have considered the topic, but this study is the first detailed, genuinely comprehensive, and systematic comparison. The results make it simpler to locate and compare indices. It is now easier for users to reflect on the merits of all available thermal indices and decide which is most suitable for a particular application or investigation.

  19. Delta and fan morphologies on Mars as climate indicators (Utrecht Studies in Geosciences 042)

    NARCIS (Netherlands)

    de Villiers, G.

    2013-01-01

    The presence, duration and quantity of water on Mars remains an important research topic in planetary science. Large valley networks, regional outflow channels, and small-scale gullies indicate the presence of water on the surface at certain points in the past. However, the climatic history and

  20. Evidence of multidecadal climate variability and the Atlantic Multidecadal Oscillation from a Gulf of Mexico sea-surface temperature-proxy record

    Science.gov (United States)

    Poore, R.Z.; DeLong, K.L.; Richey, J.N.; Quinn, T.M.

    2009-01-01

    A comparison of a Mg/Ca-based sea-surface temperature (SST)-anomaly record from the northern Gulf of Mexico, a calculated index of variability in observed North Atlantic SST known as the Atlantic Multidecadal Oscillation (AMO), and a tree-ring reconstruction of the AMO contain similar patterns of variation over the last 110 years. Thus, the multidecadal variability observed in the instrumental record is present in the tree-ring and Mg/Ca proxy data. Frequency analysis of the Gulf of Mexico SST record and the tree-ring AMO reconstruction from 1550 to 1990 found similar multidecadal-scale periodicities (???30-60 years). This multidecadal periodicity is about half the observed (60-80 years) variability identified in the AMO for the 20th century. The historical records of hurricane landfalls reveal increased landfalls in the Gulf Coast region during time intervals when the AMO index is positive (warmer SST), and decreased landfalls when the AMO index is negative (cooler SST). Thus, we conclude that alternating intervals of high and low hurricane landfall occurrences may continue on multidecadal timescales along the northern Gulf Coast. However, given the short length of the instrumental record, the actual frequency and stability of the AMO are uncertain, and additional AMO proxy records are needed to establish the character of multidecadal-scale SST variability in the North Atlantic. ?? 2009 US Government.

  1. Linear trend and abrupt changes of climate indices in the arid region of northwestern China

    Science.gov (United States)

    Wang, Huaijun; Pan, Yingping; Chen, Yaning; Ye, Zhengwei

    2017-11-01

    In recent years, climate extreme events have caused increasing direct economic and social losses in the arid region of northwestern China. Based on daily temperature and precipitation data from 1960 to 2010, this paper discussed the linear trend and abrupt changes of climate indices. The general evolution was obtained by the empirical orthogonal function (EOF), the Mann-Kendall test, and the distribution-free cumulative sum chart (CUSUM) test. The results are as follows: (1) climate showed a warming trend at annual and seasonal scale, with all temperature indices exhibiting statistically significant changes. The warm indices have increased, with 1.37%days/decade of warm days (TX90p), 0.17 °C/decade of warmest days (TXx) and 1.97 days/decade of warm spell duration indicator (WSDI), respectively. The cold indices have decreased, with - 1.89%days/decade, 0.65 °C/decade and - 0.66 days/decade for cold nights (TN10p), coldest nights (TNn) and cold spell duration indicator (CSDI), respectively. The precipitation indices have also increased significantly, coupled with the changes of magnitude (max 1-day precipitation amount (RX1day)), frequency (rain day (R0.1)), and duration (consecutive dry days (CDD)). (2) Abrupt changes of the annual regional precipitation indices and the minimum temperature indices were observed around 1986, and that of the maximum temperature indices were observed in 1996. (3) The EOF1 indicated the overall coherent distribution for the whole study area, and its principal component (PC1) was also observed, showing a significant linear trend with an abrupt change, which were in accordance with the regional observation results. EOF2 and EOF3 show contrasts between the southern and northern study areas, and between the eastern and western study areas, respectively, whereas no significant tendency was observed for their PCs. Hence, the climate indices have changed significantly, with linear trends and abrupt changes noted for all climate indices

  2. Effects of climate change on agroclimatic indices in rainfed wheat production areas of Iran

    Directory of Open Access Journals (Sweden)

    mehdi nassiri mahalati

    2009-06-01

    Full Text Available Despite the importance of all climatic parameters for crop growth and productivity, temperature and rainfall are more crucial compared to others and almost all climatic and agroclimatic indices are based on these two variables. Climate change will lead to variation in agroclimatic indices and evaluation of this variation is a key to study crop response to future climatic conditions. Length of growing period (LGP and rainfall deficit index could be used as indictors for assessment of potential impact of climate change of rainfed systems. To study this impact long-term weather data of main rainfed wheat production areas of Iran were collected. UKMO general circulation model was used for perdiction of climatic parameters of selected stations for years 2025 and 2050 based on pre defined scenarios of IPCC for this target years. LGP, length of dry season and rainfall deficit index were calculated from present data and the generated data for target years. The results showed that LGP based on temperature would be increased in all rainfed areas of country. However, including the water availability in the calculation was led to a lowered LGP. Reduction of LGP for the studied stations was in the range of 8-36 and 19-55 days for years 2025 and 2050, respectively. Rainfall deficit index for 2025 and 2050 was varied, respectively at 8.3-17.7 and 21.1-32.3 mm. It was estimated that under climatic condition of years 2025 and 2050 the cultivated areas in the main rainfed production regions of the country would be reduced by 16-25 and 23-33%, respectively.

  3. Workplace drinking climate, stress, and problem indicators: assessing the influence of teamwork (group cohesion).

    Science.gov (United States)

    Bennett, J B; Lehman, W E

    1998-09-01

    While job-related alcohol use may be associated with problems for drinkers, less is known about the effects of employee drinking on co-workers. We hypothesized that either exposure to co-worker drinking or the presence of a drinking climate would positively correlate with reports of stress and other problems. Following previous research, we also predicted that work group cohesion (or team orientation) would buffer against such problems. Two random samples of municipal employees (Ns = 909 and 1,068) completed anonymous surveys. These assessed individual drinking, co-worker drinking, task-oriented group cohesion, the direct reports of negative consequences due to co-worker substance use, and five problem indicators: job stress, job withdrawal, health problems, and performance (work accidents and absences). In each sample, drinking climate correlated with stress and withdrawal more so than did reports of individual drinking. Drinking climate and individual job stress were negatively associated with cohesion. ANCOVA results indicated that drinking climate combined with low cohesion resulted in increased vulnerability for all five problems. Moreover, cohesion appeared to attenuate the negative impact of exposure to drinking norms. As many as 40% of employees report at least one negative consequence associated with co-worker substance use (alcohol and drugs). Because teamwork may buffer negative effects of drinking climate on co-workers, workplace prevention efforts might be enhanced through a focus on the social environment. These efforts would include team-building and discussions of the impact of co-worker drinking on employee productivity.

  4. Physicians' Involvement with the New York State Health Care Proxy

    Science.gov (United States)

    Heyman, Janna C.; Sealy, Yvette M.

    2011-01-01

    This study examined physicians' attitude, involvement, and perceived barriers with the health care proxy. A cross sectional, correlational design was used to survey practicing physicians (N = 70). Physicians had positive attitudes toward the health care proxy and indicated that the most significant barriers to health care proxy completion were…

  5. A framework to assess the impacts of climate change on stream health indicators in Michigan watersheds

    Science.gov (United States)

    Woznicki, S. A.; Nejadhashemi, A. P.; Tang, Y.; Wang, L.

    2016-12-01

    Climate change is projected to alter watershed hydrology and potentially amplify nonpoint source pollution transport. These changes have implications for fish and macroinvertebrates, which are often used as measures of aquatic ecosystem health. By quantifying the risk of adverse impacts to aquatic ecosystem health at the reach-scale, watershed climate change adaptation strategies can be developed and prioritized. The objective of this research was to quantify the impacts of climate change on stream health in seven Michigan watersheds. A process-based watershed model, the Soil and Water Assessment Tool (SWAT), was linked to adaptive neuro-fuzzy inferenced (ANFIS) stream health models. SWAT models were used to simulate reach-scale flow regime (magnitude, frequency, timing, duration, and rate of change) and water quality variables. The ANFIS models were developed based on relationships between the in-stream variables and sampling points of four stream health indicators: the fish index of biotic integrity (IBI), macroinvertebrate family index of biotic integrity (FIBI), Hilsenhoff biotic index (HBI), and number of Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa. The combined SWAT-ANFIS models extended stream health predictions to all watershed reaches. A climate model ensemble from the Coupled Model Intercomparison Project Phase 5 (CMIP5) was used to develop projections of changes to flow regime (using SWAT) and stream health indicators (using ANFIS) from a baseline of 1980-2000 to 2020-2040. Flow regime variables representing variability, duration of extreme events, and timing of low and high flow events were sensitive to changes in climate. The stream health indicators were relatively insensitive to changing climate at the watershed scale. However, there were many instances of individual reaches that were projected to experience declines in stream health. Using the probability of stream health decline coupled with the magnitude of the decline, maps of

  6. Jemen - the Proxy War

    OpenAIRE

    Magdalena El Ghamari

    2015-01-01

    The military operation in Yemen is significant departure from Saudi Arabia's foreign policy tradition and customs. Riyadh has always relied on three strategies to pursue its interests abroad: wealth, establish a global network and muslim education and diplomacy and meadiation. The term "proxy war" has experienced a new popularity in stories on the Middle East. A proxy war is two opposing countries avoiding direct war, and instead supporting combatants that serve their interests. In some occas...

  7. Biodiversity Indicators Show Climate Change Will Alter Vegetation in Parks and Protected Areas

    Directory of Open Access Journals (Sweden)

    Nicholas C. Coops

    2013-05-01

    Full Text Available While multifaceted, a chief aim when designating parks and protected areas is to support the preservation of biological diversity, in part, through representing and conserving the full range of landscape conditions observed throughout a representative area. Parks and protected areas are, however, typically developed using a static interpretation of current biodiversity and landscape conditions. The observed and potential climate change impacts to biodiversity have created a need to also contemplate how parks and protected areas will respond to climate change and how these areas will represent the future range of landscape conditions. To assess change in biodiversity, broad-scale ecosystem information can be sourced from indirect remotely sensed indicators. Quantifying biodiversity through indirect indicators allows characterization of inter-relationships between climate and biodiversity. Such characterizations support the assessment of possible implications of climatic change, as the indicators can be generated using modeled forecasts of future climatic conditions. In this paper we model and map impacts of climate change on British Columbia’s parks and protected areas by quantifying change in a number of remotely sensed indicators of biodiversity. These indicators are based on the measured amount of incoming solar energy used by vegetation and map the overall annual energy utilization, variability (seasonality, and latent or baseline energy. We compare current conditions represented by parks and protected areas, to those forecasted in the year 2065. Our results indicate that parks and protected areas are forecasted to become more productive and less seasonal, due to increased vegetation productivity in higher elevation environments. While increased vegetation productivity may be beneficial for biodiversity overall, these changes will be particularly problematic for sensitive and specialist species. Future gaps in vegetation conditions

  8. Comparison of several climate indices as inputs in modelling of the Baltic Sea runoff

    Energy Technology Data Exchange (ETDEWEB)

    Hanninen, J.; Vuorinen, I. [Turku Univ. (Finland). Archipelaco Research Inst.], e-mail: jari.hanninen@utu.fi

    2012-11-01

    Using Transfer function (TF) models, we have earlier presented a chain of events between changes in the North Atlantic Oscillation (NAO) and their oceanographical and ecological consequences in the Baltic Sea. Here we tested whether other climate indices as inputs would improve TF models, and our understanding of the Baltic Sea ecosystem. Besides NAO, the predictors were the Arctic Oscillation (AO), sea-level air pressures at Iceland (SLP), and wind speeds at Hoburg (Gotland). All indices produced good TF models when the total riverine runoff to the Baltic Sea was used as a modelling basis. AO was not applicable in all study areas, showing a delay of about half a year between climate and runoff events, connected with freezing and melting time of ice and snow in the northern catchment area of the Baltic Sea. NAO appeared to be most useful modelling tool as its area of applicability was the widest of the tested indices, and the time lag between climate and runoff events was the shortest. SLP and Hoburg wind speeds showed largely same results as NAO, but with smaller areal applicability. Thus AO and NAO were both mostly contributing to the general understanding of climate control of runoff events in the Baltic Sea ecosystem. (orig.)

  9. Hydrologic benchmarking of meteorological drought indices at interannual to climate change timescales: a case study over the Amazon and Mississippi river basins

    Science.gov (United States)

    Joetzjer, E.; Douville, H.; Delire, C.; Ciais, P.; Decharme, B.; Tyteca, S.

    2013-12-01

    Widely used metrics of drought are still derived solely from analyses of meteorological variables such as precipitation and temperature. While drought is generally a consequence of atmospheric anomalies, the impacts to society are more directly related to hydrologic conditions. The present study uses a standardized runoff index (SRI) as a proxy for river discharge and as a benchmark for various meteorological drought indices (scPDSI, SPI, SPEI_th, and SPEI_hg respectively). Only 12-month duration droughts are considered in order to allow a direct (no river routing) comparison between meteorological anomalies and their hydrological counterpart. The analysis is conducted over the Mississippi and Amazon river basins, which provide two contrasted test beds for evaluating drought indices at both interannual (using detrended data) and climate change (using raw data) timescales. Looking first at observations over the second half of the 20th century, the simple SPI based solely on precipitation is no less suitable than more sophisticated meteorological drought indices at detecting interannual SRI variations. Using the detrended runoff and meteorological outputs of a five-member single model ensemble of historical and 21th century climate simulations leads to the same conclusion. Looking at the 21st century projections, the response of the areal fraction in drought to global warming is shown to be strongly metric dependent and potentially overestimated by the drought indices which account for temperature variations. These results suggest that empirical meteorological drought indices should be considered with great caution in a warming climate and that more physical water balance models are needed to account for the impact of the anthropogenic radiative forcings on hydrological droughts.

  10. The coralline red alga Lithophyllum kotschyanum f. affine as proxy of climate variability in the Yemen coast, Gulf of Aden (NW Indian Ocean)

    Science.gov (United States)

    Caragnano, A.; Basso, D.; Jacob, D. E.; Storz, D.; Rodondi, G.; Benzoni, F.; Dutrieux, E.

    2014-01-01

    Recent investigations have shown the potential of red coralline algae as paleoclimatic archive. A previously unexplored subfamily of coralline algae, the Lithophylloideae, was investigated from the Gulf of Aden (Balhaf, Yemen). Seasonal changes in Mg/Ca, Li/Ca and Ba/Ca composition of Lithophyllum kotschyanum f. affine were investigated by Laser Ablation-Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). For the first time in coralline algae, the Li/Ca composition was analyzed and showed a highly significant and positive correlation with Mg/Ca and SST. Monthly algal Mg/Ca and Li/Ca variations indicate a positive correlation with sea surface temperature (SST), and sea surface salinity (SSS), although low growth rates decrease the resolution of the algal record. Albeit no or weak positive correlation between monthly algal Ba/Ca and local SST was found, fluctuations in Ba/Ca suggest the seasonal influence of nutrient-rich deep waters introduced by upwelling, and record an increase of sedimentation at the sampling site likely due to an intensified land use in the area. The Mg/Ca age model shows an average algal extension rate of 1.15 mm yr-1, and reveals multiple intra-annual banding (previously unreported in the genus Lithophyllum) together with carposporangia formation in late February-early March, when temperature begins to increase. The concentration of MgCO3 in the thallus of L. kotschyanum f. affine is 20 mol% (1 SE), confirming that within the genus, the species sampled in warmer regions contain higher mol% MgCO3. The concentrations of LiCO3 and BaCO3 are 8 μmol% (0.7 SE) and 0.5 μmol% (0.03 SE), respectively. Despite the limitations from low-growth rate and species-specific vital effect, coralline algae confirm their utility in climate and oceanographic reconstruction.

  11. Indigenous community health and climate change: integrating biophysical and social science indicators

    Science.gov (United States)

    Donatuto, Jamie; Grossman, Eric E.; Konovsky, John; Grossman, Sarah; Campbell, Larry W.

    2014-01-01

    This article describes a pilot study evaluating the sensitivity of Indigenous community health to climate change impacts on Salish Sea shorelines (Washington State, United States and British Columbia, Canada). Current climate change assessments omit key community health concerns, which are vital to successful adaptation plans, particularly for Indigenous communities. Descriptive scaling techniques, employed in facilitated workshops with two Indigenous communities, tested the efficacy of ranking six key indicators of community health in relation to projected impacts to shellfish habitat and shoreline archaeological sites stemming from changes in the biophysical environment. Findings demonstrate that: when shellfish habitat and archaeological resources are impacted, so is Indigenous community health; not all community health indicators are equally impacted; and, the community health indicators of highest concern are not necessarily the same indicators most likely to be impacted. Based on the findings and feedback from community participants, exploratory trials were successful; Indigenous-specific health indicators may be useful to Indigenous communities who are assessing climate change sensitivities and creating adaptation plans.

  12. Establishment of an indicator concept for the German strategy on adaptation to climate change

    Energy Technology Data Exchange (ETDEWEB)

    Schoenthaler, Konstanze; Andrian-Werburg, Stefan von; Wulfert, Katrin [Bosch und Partner GmbH, Muenchen (Germany); Luthardt, Vera; Kreinsen, Beatrice; Schultz-Sternberg, R.; Hommel, Robert [Hochschule fuer Nachhaltige Entwicklung Eberswalde (Germany)

    2010-11-15

    Even if we succeed in achieving the EU target of reducing global warming to 2 C, it will be absolutely essential to adapt to changing climatic conditions. The greenhouse gases currently present in the atmosphere will influence the climate in coming decades. The day on which it is quite clear which climatic scenario prevails, so that it is possible to model all relevant processes down to regional level, will be the day on which it is too late to adapt to the actual scenario. Our endeavours to adapt to climate change do not mean, however, that we can neglect to take measures in order to reduce the output of greenhouse gases. It is important to remember that on their own, neither adaptation nor mitigation can prevent the grave impacts resulting from climate change. In fact, they complement each other meaningfully thus helping to alleviate the risks of climate change. On 17th December 2008 the German Federal Cabinet adopted the DAS (German Strategy for the Adaptation to Climate Change), (Bundesregierung 2008). The DAS has created the framework for adapting to the consequences of climate change in Germany. First and fore-most, the DAS contributes its guidelines at Federal level, to provide a guideline for agents at other levels. The Strategy lays the foundation for a medium-term process. In conjunction with the individual Federal States and other groups representing various sectors of society, the Strategy provides a step-by-step assessment of the risks of climate change. Furthermore, it states the potential requirements for action, and defines the appropriate goals and potential adaptation measures to be developed and implemented in this process. In due course, the Federal Environment Agency (UBA) will design a comprehensive set of tools to support and advance the DAS. An integral part of this will be the Special Information System 'Adaptation' (FISKA) and an Indicator System to aid adaptation. The latter is one of the key tasks identified for the DAS. As far

  13. Indicators for Tracking European Vulnerabilities to the Risks of Infectious Disease Transmission due to Climate Change

    Directory of Open Access Journals (Sweden)

    Jonathan E. Suk

    2014-02-01

    Full Text Available A wide range of infectious diseases may change their geographic range, seasonality and incidence due to climate change, but there is limited research exploring health vulnerabilities to climate change. In order to address this gap, pan-European vulnerability indices were developed for 2035 and 2055, based upon the definition vulnerability = impact/adaptive capacity. Future impacts were projected based upon changes in temperature and precipitation patterns, whilst adaptive capacity was developed from the results of a previous pan-European study. The results were plotted via ArcGISTM to EU regional (NUTS2 levels for 2035 and 2055 and ranked according to quintiles. The models demonstrate regional variations with respect to projected climate-related infectious disease challenges that they will face, and with respect to projected vulnerabilities after accounting for regional adaptive capacities. Regions with higher adaptive capacities, such as in Scandinavia and central Europe, will likely be better able to offset any climate change impacts and are thus generally less vulnerable than areas with lower adaptive capacities. The indices developed here provide public health planners with information to guide prioritisation of activities aimed at strengthening regional preparedness for the health impacts of climate change. There are, however, many limitations and uncertainties when modeling health vulnerabilities. To further advance the field, the importance of variables such as coping capacity and governance should be better accounted for, and there is the need to systematically collect and analyse the interlinkages between the numerous and ever-expanding environmental, socioeconomic, demographic and epidemiologic datasets so as to promote the public health capacity to detect, forecast, and prepare for the health threats due to climate change.

  14. Indicators for tracking European vulnerabilities to the risks of infectious disease transmission due to climate change.

    Science.gov (United States)

    Suk, Jonathan E; Ebi, Kristie L; Vose, David; Wint, Willy; Alexander, Neil; Mintiens, Koen; Semenza, Jan C

    2014-02-21

    A wide range of infectious diseases may change their geographic range, seasonality and incidence due to climate change, but there is limited research exploring health vulnerabilities to climate change. In order to address this gap, pan-European vulnerability indices were developed for 2035 and 2055, based upon the definition vulnerability = impact/adaptive capacity. Future impacts were projected based upon changes in temperature and precipitation patterns, whilst adaptive capacity was developed from the results of a previous pan-European study. The results were plotted via ArcGISTM to EU regional (NUTS2) levels for 2035 and 2055 and ranked according to quintiles. The models demonstrate regional variations with respect to projected climate-related infectious disease challenges that they will face, and with respect to projected vulnerabilities after accounting for regional adaptive capacities. Regions with higher adaptive capacities, such as in Scandinavia and central Europe, will likely be better able to offset any climate change impacts and are thus generally less vulnerable than areas with lower adaptive capacities. The indices developed here provide public health planners with information to guide prioritisation of activities aimed at strengthening regional preparedness for the health impacts of climate change. There are, however, many limitations and uncertainties when modeling health vulnerabilities. To further advance the field, the importance of variables such as coping capacity and governance should be better accounted for, and there is the need to systematically collect and analyse the interlinkages between the numerous and ever-expanding environmental, socioeconomic, demographic and epidemiologic datasets so as to promote the public health capacity to detect, forecast, and prepare for the health threats due to climate change.

  15. Do Himalayan treelines respond to recent climate change? An evaluation of sensitivity indicators

    Science.gov (United States)

    Schickhoff, U.; Bobrowski, M.; Bohner, J.; Burzle, B.; Chaudhary, R. P.; Gerlitz, L.; Heyken, H.; Lange, J.; Muller, M.; Scholten, T.; Schwab, N.; Wedegartner, R.

    2015-05-01

    Climate warming is expected to induce treelines to advance to higher elevations. Empirical studies in diverse mountain ranges, however, give evidence of both advancing alpine treelines and rather insignificant responses. The inconsistency of findings suggests distinct differences in the sensitivity of global treelines to recent climate change. It is still unclear where Himalayan treeline ecotones are located along the response gradient from rapid dynamics to apparently complete inertia. This paper reviews the current state of knowledge regarding sensitivity and response of Himalayan treelines to climate warming, based on extensive field observations, published results in the widely scattered literature, and novel data from ongoing research of the present authors. Several sensitivity indicators such as treeline type, treeline form, seed-based regeneration, and growth patterns are evaluated. Since most Himalayan treelines are anthropogenically depressed, observed advances are largely the result of land use change. Near-natural treelines are usually krummholz treelines, which are relatively unresponsive to climate change. Nevertheless, intense recruitment of treeline trees suggests a great potential for future treeline advance. Competitive abilities of seedlings within krummholz thickets and dwarf scrub heaths will be a major source of variation in treeline dynamics. Tree growth-climate relationships show mature treeline trees to be responsive to temperature change, in particular in winter and pre-monsoon seasons. High pre-monsoon temperature trends will most likely drive tree growth performance in the western and central Himalaya. Ecological niche modelling suggests that bioclimatic conditions for a range expansion of treeline trees will be created during coming decades.

  16. Deriving evaluation indicators for knowledge transfer and dialogue processes in the context of climate research

    Science.gov (United States)

    Treffeisen, Renate; Grosfeld, Klaus; Kuhlmann, Franziska

    2017-12-01

    Knowledge transfer and dialogue processes in the field of climate science have captured intensive attention in recent years as being an important part of research activities. Therefore, the demand and pressure to develop a set of indicators for the evaluation of different activities in this field have increased, too. Research institutes are being asked more and more to build up structures in order to map these activities and, thus, are obliged to demonstrate the success of these efforts. This paper aims to serve as an input to stimulate further reflection on the field of evaluation of knowledge transfer and dialogue processes in the context of climate sciences. The work performed in this paper is embedded in the efforts of the German Helmholtz Association in the research field of earth and environment and is driven by the need to apply suitable indicators for knowledge transfer and dialogue processes in climate research center evaluations. We carry out a comparative analysis of three long-term activities and derive a set of indicators for measuring their output and outcome by balancing the wide diversity and range of activity contents as well as the different tools to realize them. The case examples are based on activities which are part of the regional Helmholtz Climate Initiative Regional Climate Change (REKLIM) and the Climate Office for Polar Regions and Sea Level Rise at the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research. Both institutional units have been working on a wide range of different knowledge transfer and dialogue processes since 2008/2009. We demonstrate that indicators for the evaluation must be based on the unique objectives of the individual activities and the framework they are embedded in (e.g., research foci which provide the background for the performed knowledge transfer and dialogue processes) but can partly be classified in a principle two-dimensional scheme. This scheme might serve as a usable basis for climate

  17. HIRS channel 12 brightness temperature dataset and its correlations with major climate indices

    Directory of Open Access Journals (Sweden)

    L. Shi

    2013-07-01

    Full Text Available A new version of the High-Resolution Infrared Radiation Sounder (HIRS upper tropospheric water vapor channel (channel 12 brightness temperature dataset is developed using intersatellite calibrated data. In this dataset, only those pixels affected by upper tropospheric clouds are discarded. Compared to the previous version that was based on column-clear-sky data, the new version has much better daily spatial coverage. The HIRS observation patterns are compared to microwave sounder measurements. The differences between the two types of sounders vary with respect to brightness temperature with larger differences for higher (dry values. Correlations between the HIRS upper tropospheric water vapor channel brightness temperatures and several major climate indices show strong signals during cold seasons. The selected climate indices track climate variation signals covering regions from the tropics to the poles. Qualitatively, moist signals are correlated with troughs and ascending branches of the circulation, while dry signals occur with ridges and descent. These correlations show the potential of using the upper tropospheric water vapor channel brightness temperature dataset together with a suite of many atmospheric variables to monitor regional climate changes and locate global teleconnection patterns.

  18. Influence of Global Climate Indices and Inter-annual Wind Speed Variability in the UAE

    Science.gov (United States)

    Naizghi, M. S.; Ouarda, T.

    2016-12-01

    Wind is becoming one of the world's most favourable source of sustainable energy. Its stochastic nature, however, is a challenge to fully exploit its potential. To overcome this limitation, a number of studies focusing on modelling the character of wind were conducted but few explored the effect of large-scale climatological factors on wind distribution and variation. The present study aims to: first, examine the variability and change points in wind speed time series data. Second, identify the teleconnections between the wind speed and climate indices by applying wavelet coherence analysis. Third, develop multiple linear regression models to represent wind speed as a function of climate indices. The study is carried out using wind speed data collected from six ground stations in the UAE and a reanalysis gridded dataset. Continuous wavelet analysis on the wind speed indicated annual periodicity in all stations and biannual in three. Trend analysis using Modified Mann-Kendall test and linear regression showed that half of the stations have a significant trend at the 5% level. Cumulative sum and Bayesian change detection analysis revealed all stations, except one, exhibited change points with statistical significance level of 5%. Wavelet coherence analysis demonstrated that wind speed in the UAE is mainly associated with the North Atlantic Oscillation (NAO), East Atlantic Oscillation (EAO), El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). NAO and EAO simultaneously modulate wind speed in the summer while ENSO and IOD influence winter and autumn wind speeds. Step-wise multiple linear regression models developed to select appropriate predictors among the various climate indices resulted in limited success. Further work on predictive models using non-linear models and generalized additive model are being explored. Keywords: Climate indices, teleconnections, wavelet analysis, wind speed variability, trend analysis, change point, UAE.

  19. Towards a Comparative Index of Seaport Climate-Risk: Development of Indicators from Open Data

    Science.gov (United States)

    McIntosh, R. D.; Becker, A.

    2016-02-01

    Seaports represent an example of coastal infrastructure that is at once critical to global trade, constrained to the land-sea interface, and exposed to weather and climate hazards. Seaports face impacts associated with projected changes in sea level, sedimentation, ocean chemistry, wave dynamics, temperature, precipitation, and storm frequency and intensity. Port decision-makers have the responsibility to enhance resilience against these impacts. At the multi-port (regional or national) scale, policy-makers must prioritize adaptation efforts to maximize the efficiency of limited physical and financial resources. Prioritization requires comparing across seaports, and comparison requires a standardized assessment method, but efforts to date have either been limited in scope to exposure-only assessments or limited in scale to evaluate one port in isolation from a system of ports. In order to better understand the distribution of risk across ports and to inform transportation resilience policy, we are developing a comparative assessment method to measure the relative climate-risk faced by a sample of ports. Our mixed-methods approach combines a quantitative, data-driven, indicator-based assessment with qualitative data collected via expert-elicitation. In this presentation, we identify and synthesize over 120 potential risk indicators from open data sources. Indicators represent exposure, sensitivity, and adaptive capacity for a pilot sample of 20 ports. Our exploratory data analysis, including Principal Component Analysis, uncovered sources of variance between individual ports and between indicators. Next steps include convening an expert panel representing the perspectives of multiple transportation system agencies to find consensus on a suite of robust indicators and metrics for maritime freight node climate risk assessment. The index will be refined based on expert feedback, the sample size expanded, and additional indicators sought from closed data sources

  20. A comparative performance analysis of three standardized climatic drought indices in the Chi River basin, Thailand

    Directory of Open Access Journals (Sweden)

    Tipaporn Homdee

    2016-05-01

    Full Text Available Drought indices are generally used as a tool for monitoring changes in drought conditions. This paper evaluated the performance of three climatic drought indices to characterize drought trends in the Chi River basin in Northeast Thailand. Initially, the drought assessment was conducted using the Standardized Precipitation Index (SPI, a precipitation-based index, and the Standardized Precipitation Evapotranspiration Index (SPEI, an index taking into account the difference between precipitation and potential evapotranspiration (PET. Then, this study simply applied an index called the Standardized Precipitation Actual Evapotranspiration Index (SPAEI, similar to the commonly used SPEI, with the difference being in the use of actual evapotranspiration (AET instead of PET. Time series of the three indices were compared with observed droughts. The results indicated that various indicators of different indices can have diverse effects on drought conditions. The simple SPI, considering only precipitation, can be used to identify characteristics of droughts with certain restrictions. Being multivariate indices, the SPEI and the SPAEI were able to clearly detect the temporal variability of droughts to a greater extent than the SPI index. Moreover, the different results derived from using P-AET instead of P-PET made a substantial difference to temporal drought severity. Thus, climatic water demand had important aspects in determining the drought conditions for this area.

  1. Climate based suitability indices as a mean to improve revegetation success

    Science.gov (United States)

    Baumgartl, Thomas; Lechner, Alex; Audet, Patrick; Arnold, Sven

    2014-05-01

    In arid and semi-arid environments, availability of water for successful revegetation of disturbed land, e.g. through mining, plays a major role. This refers to availability of water prior or during the time of seed dormancy, germination and growth of seedlings. The success and in consequence the type of vegetation community is controlled in general by climatic conditions but also by the specific conditions at the time of germination. Generalised climatic data and classifications have proven to be not well suited for the prediction of type of vegetation community or germination success in climatic conditions, which are highly variable. For example this is the case in the semi-arid and arid environments of northern Australia where rainfall is very variable and the occurrence of rainfall can be very erratic. For further investigation of this characteristic, a set of indices has been developed, which are deemed to better describe the suitability of the climatic conditions for rehabilitation. In total nine locations across Queensland, Australia, ranging from the north to the south over a distance of approximately 2000 km have been analysed using this approach. The calculations showed that regular rainfall and relatively short periods of water-deficit are key characteristics of climate suitability. The comparison of the investigated locations allowed the separation in suitable and susceptible locations regarding the availability of water, amount of rain and duration of drought between rain events. The suitability indices were compared with natural vegetation patterns expressed through biomass and by averaging NDVI values during pronounced dry and wet periods (El Nino, La Nina). Specific estimates of climate suitability are rarely considered in assessments of re-vegetation of degraded or otherwise disturbed land (e.g. mining). However, it can be assumed that the regional intensity, seasonality, and extremity of climate should represent an overarching component of

  2. Developing a reduced-form ensemble of climate change scenarios for Europe and its application to selected impact indicators

    Czech Academy of Sciences Publication Activity Database

    Dubrovský, Martin; Trnka, M.; Holman, I. P.; Svobodová, E.; Harrison, P. A.

    2015-01-01

    Roč. 128, 3-4 (2015), s. 169-186 ISSN 0165-0009 R&D Projects: GA MŠk LD12029 Institutional support: RVO:68378289 Keywords : global Climate Model * ensemble of models * climate change * climate change scenarios * climate change impact indices * Europe Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 3.344, year: 2015 http://link.springer.com/article/10.1007%2Fs10584-014-1297-7

  3. Lake ecosystem response to climate change 8200 years ago. A multi-proxy study at Lake Højby Sø, Denmark

    DEFF Research Database (Denmark)

    Rasmussen, Peter; Hede, Mikkel Ulfeldt; Noe-Nygaard, Nanna

    2009-01-01

    of the North Atlantic is projected by almost all global-warming models (e.g. IPCC 2007). In Denmark the 8.2 kyr event pre-dates the introduction of agriculture (by more than two millennia) and any other major human impact on the environment, so allowing the anthropogenic factor to be disregarded. At Lake Højby......The assessment of present-day climate effects on lake ecosystems in lowland Europe is difficult for two reasons: i. the absence of long-term monitoring data (usually less than 30 yrs) which makes it difficult to determine natural variation, and ii. the problem of distinguishing between the effects...... of climate and the effects of human activities. These problems also complicate the prediction of possible future climate influence on lake ecology. A way of circumventing these problems is the use of lake sediment records which contain a wealth of information about past lake history over long time scales...

  4. Soils and climate: redness and weathering as indicators of mean annual precipitation

    Science.gov (United States)

    Lucke, Bernhard

    2016-04-01

    Paleosols can be used as archives of past changes of climate and landscapes, but their interpretation has to be based on modern analogies such as Budyko's law of soil zonality. These can be very useful if the respective processes of soil formation are sufficiently well understood. However, some soils such as the Terra Rossa or Red Mediterranean Soils, that are widespread at the fringes of the steppes and deserts, are still disputed with regard to their genesis and environmental significance. In particular, there is no agreement whether they resemble current environmental conditions, or are inherited from climates or sediments of the past. In this context, a remarkable change of the color of surface soils can be observed when driving from the city of Irbid in Jordan towards the east. Soil color apparently changes slowly, but steadily from dark red to yellow colors. However, attempting to express these color changes in numerical form is challenging, and it seemed questionable whether color is indeed connected with soil weathering intensity, or an optical illusion. However, a systematic comparison of different approaches of calculating soil redness found that the CIELAB-color system is suited for numerical expressions of soil redness and performs better than the Munsell charts. Along the investigated transect in Jordan, soil color seems strongly connected with weathering intensity, since various weathering indicators point to a steady increase of soil development with moisture. This suggests that such indices can well be used in semi-arid areas of 250-600 mm of mean annual precipitation. A very strong correlation of magnetic enhancement and rainfall indicates that the investigated soils are forming in equilibrium with current climatic conditions, and regressions based on this gradient might be suited for estimating paleorainfalls recorded by buried paelosols. It seems therefore that surface Terra Rossa soils in Jordan can be in equilibrium with current climate

  5. Validating the Heat Stress Indices for Using In Heavy Work Activities in Hot and Dry Climates.

    Science.gov (United States)

    Hajizadeh, Roohalah; Golbabaei, Farideh; Farhang Dehghan, Somayeh; Beheshti, Mohammad Hossein; Jafari, Sayed Mohammad; Taheri, Fereshteh

    2016-01-01

    Necessity of evaluating heat stress in the workplace, require validation of indices and selection optimal index. The present study aimed to assess the precision and validity of some heat stress indices and select the optimum index for using in heavy work activities in hot and dry climates. It carried out on 184 workers from 40 brick kilns workshops in the city of Qom, central Iran (as representative hot and dry climates). After reviewing the working process and evaluation the activity of workers and the type of work, environmental and physiological parameters according to standards recommended by International Organization for Standardization (ISO) including ISO 7243 and ISO 9886 were measured and indices were calculated. Workers engaged in indoor kiln experienced the highest values of natural wet temperature, dry temperature, globe temperature and relative humidity among studied sections (Pstress index (HSI) indices had the highest correlation with other physiological parameters among the other heat stress indices. Relationship between WBGT index and carotid artery temperature (r=0.49), skin temperature (r=0.319), and oral temperature (r=0.203) was statistically significant (P=0.006). Since WBGT index, as the most applicable index for evaluating heat stress in workplaces is approved by ISO, and due to the positive features of WBGT such as ease of measurement and calculation, and with respect to some limitation in application of HSI; WBGT can be introduced as the most valid empirical index of heat stress in the brick workshops.

  6. Identification of relationships between climate indices and long-term precipitation in South Korea using ensemble empirical mode decomposition

    Science.gov (United States)

    Kim, Taereem; Shin, Ju-Young; Kim, Sunghun; Heo, Jun-Haeng

    2018-02-01

    Climate indices characterize climate systems and may identify important indicators for long-term precipitation, which are driven by climate interactions in atmosphere-ocean circulation. In this study, we investigated the climate indices that are effective indicators of long-term precipitation in South Korea, and examined their relationships based on statistical methods. Monthly total precipitation was collected from a total of 60 meteorological stations, and they were decomposed by ensemble empirical mode decomposition (EEMD) to identify the inherent oscillating patterns or cycles. Cross-correlation analysis and stepwise variable selection were employed to select the significant climate indices at each station. The climate indices that affect the monthly precipitation in South Korea were identified based on the selection frequencies of the selected indices at all stations. The NINO12 indices with four- and ten-month lags and AMO index with no lag were identified as indicators of monthly precipitation in South Korea. Moreover, they indicate meaningful physical information (e.g. periodic oscillations and long-term trend) inherent in the monthly precipitation. The NINO12 indices with four- and ten- month lags was a strong indicator representing periodic oscillations in monthly precipitation. In addition, the long-term trend of the monthly precipitation could be explained by the AMO index. A multiple linear regression model was constructed to investigate the influences of the identified climate indices on the prediction of monthly precipitation. Three identified climate indices successfully explained the monthly precipitation in the winter dry season. Compared to the monthly precipitation in coastal areas, the monthly precipitation in inland areas showed stronger correlation to the identified climate indices.

  7. Testing the Value of Information of Climate Change Indicators that use Earth Observations

    Science.gov (United States)

    Kenney, M. A.

    2012-12-01

    Indicators are usually thought of as measurements or calculations that represent important features of the status, trend, or performance of a system of interest (e.g. the economy, agriculture, air quality). They are often used for the most practical of reasons - one cannot measure everything important about systems of interest, so there is a practical need to identify major features that can be reported periodically and used to guide both research and decisions (National Research Council (NRC). 2000. Ecological Indicators for the Nation. National Academy Press. Washington, DC). The use of indicators to track the status and trends of many features of environmental or economic performance, quality of life, and a host of other social concerns is embedded in the fabric of our everyday lives. Businesses, governments, and consumers regularly use the common economic indices - e.g. the unemployment index or consumer price index - as guides for decision-making on investments and hiring. There is an analogous demand for indicators of environmental conditions and performance - everything from agricultural yields to air and water quality to weather and climate - that are currently less publicly visible than the common economic indicators, but that can have critically important uses in such areas as natural resource management, improvement of environmental quality, emergency planning, and infrastructure development. A number of these environmental indicators, be it physical or ecological, use a range of data sources including earth observations. Despite the extensive development and use of indicators, there is little testing of these indicators to assure that they indeed provide the assumed positive information benefit. This is particularly concerning because if these indicators are systematically misunderstood by the intended audience or a sub-group of that audience, such individuals could make decisions that are consistent with their incorrect understanding of the indicator

  8. The Colosseum Floras As Bio-Indicators Of The Climatic Changes In Rome

    Energy Technology Data Exchange (ETDEWEB)

    Caneva, G.; Pacini, A.; Cutini, M.; Merante, A. [Dipartimento Biologia, Universita degli Studi di Roma Tre, Viale G. Marconi, 446-00146 Rome (Italy)

    2005-06-01

    Over the last four centuries several botanists have analysed the Colosseum flora, and by using modern ecological and biogeographical approaches to these same floras, we have observed similar trends with respect to the climatic phenomena as those of the historic Torre Calandrelli Observatory and by other older historical records. The elements of which can be summarised as follows: (1) a substantial reduction of all the biogeographical components taken as indicators of cooler and damper habitats, such as the Euro-Asiatic and Boreal areas starting from the 17th Century in particular; (2) a decrease in numbers of all the species more dependent on water (independent of their chorology); (3) similar clear-cut increases in the species belonging to phytosociological classes typical to Mediterranean climatic conditions, to the detriment of those typical to Middle-European temperate bioclimates. All of which can be interpreted as clear indicators of non-negligible climatic changes towards hotter and drier conditions independent of local variations due to urbanisation.

  9. Extreme Warming Challenges Sentinel Status of Kelp Forests as Indicators of Climate Change

    Science.gov (United States)

    Miller, R. J.; Reed, D.; Washburn, L.; Rassweiler, A.; Bell, T. W.; Harrer, S.

    2016-12-01

    The ecological effects of global warming are expected to be large, but are proving difficult and costly to measure. This has led to a growing interest in using sentinel species as early warning indicators of impending climate change effects on entire ecosystems, raising awareness of the importance of verifying that such conservation shortcuts have sound biological foundations. A recent large-scale warming event in the North Pacific Ocean of unprecedented magnitude and duration allowed us to evaluate the sentinel status of giant kelp, a coastal foundation species that thrives in cold, nutrient-rich waters and considered sensitive to warming. Here we show that giant kelp did not presage ecosystem effects of extreme warming off southern California despite its expected vulnerability. Fluctuations in the biomass of giant kelp, understory algae, invertebrates and fish remained within historical ranges despite 34 months of above average temperatures and below average nutrients. Sea stars and sea urchins were exceptions, plummeting due to disease outbreaks linked to the warming. Our results challenge the IPCC predictions about the vulnerability of kelp-dominated systems to extreme warming events and question their use as early indicators of climate change. The resilience of giant kelp to unprecedented warming not only questions our understanding of kelp ecology, but exposes the risk of relying on supposed sentinel species that are assumed to be very sensitive to climate change.

  10. Long Series of GNSS Integrated Precipitable Water as a Climate Change Indicator

    Directory of Open Access Journals (Sweden)

    Kruczyk Michał

    2015-12-01

    Full Text Available This paper investigates information potential contained in tropospheric delay product for selected International GNSS Service (IGS stations in climatologic research. Long time series of daily averaged Integrated Precipitable Water (IPW can serve as climate indicator. The seasonal model of IPW change has been adjusted to the multi-year series (by the least square method. Author applied two modes: sinusoidal and composite (two or more oscillations. Even simple sinusoidal seasonal model (of daily IPW values series clearly represents diversity of world climates. Residuals in periods from 10 up to 17 years are searched for some long-term IPW trend – self-evident climate change indicator. Results are ambiguous: for some stations or periods IPW trends are quite clear, the following years (or the other station not visible. Method of fitting linear trend to IPW series does not influence considerably the value of linear trend. The results are mostly influenced by series length, completeness and data (e.g. meteorological quality. The longer and more homogenous IPW series, the better chance to estimate the magnitude of climatologic IPW changes.

  11. Bringing indices of species vulnerability to climate change into geographic space: an assessment across the Coronado national forest

    Science.gov (United States)

    Jennifer E. Davison; Sharon Coe; Deborah Finch; Erika Rowland; Megan Friggens; Lisa J. Graumlich

    2012-01-01

    Indices that rate the vulnerability of species to climate change in a given area are increasingly used to inform conservation and climate change adaptation strategies. These species vulnerability indices (SVI) are not commonly associated with landscape features that may affect local-scale vulnerability. To do so would increase their utility by allowing managers to...

  12. Vegetation changes and timberline fluctuations in the Central Alps as indicators of holocene climatic oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Wick, L.; Tinner, W. [Univ. of Bern (Switzerland)

    1997-11-01

    Pollen and plant-macrofossil data are presented for two lakes near the timberline in the Italian (Lago Basso, 2250 m) and Swiss Central Alps (Gouille Rion, 2343 m). The reforestation at both sites started at 9700-9500 BP with Pinus cembra, Larix decidua, and Betula. The timberline reached its highest elevation between 8700 and 5000 BP and retreated after 5000 BP, due to a mid-Holocene climatic change and increasing human impact since about 3500 BP (Bronze Age). The expansion of Picea abies at Lago Basso between ca. 7500 and 6200 BP was probably favored by cold phases accompanied by increased oceanicity, whereas in the area of Gouille Rion, where spruce expanded rather late (between 4500 and 3500 BP), human influence equality might have been important. The mass expansion of Alnus viridis between ca. 5000 and 3500 BP probably can be related to both climatic change and human activity at timberline. During the early and middle Holocene a series of timberline fluctuations is recorded as declines in pollen and macrofossil concentrations of the major tree species, and as increases in nonarboreal pollen in the pollen percentage diagram of Gouille Rion. Most of the periods of low timberline can be correlated by radiocarbon dating the climatic changes in the Alps as indicated by glacier advances in combination with palynological records, solifluction, and dendroclimatical data. Lago Basso and Gouille Rion are the only sites in the Alps showing complete palaeobotanical records of cold phases between 10,000 and 2000 BP with very good time control. The altitudinal range of the Holocene treeline fluctuations caused by climate most likely was not more than 100 to 150 m. A possible correlation of a cold period at ca. 7500-6500 BP (Misox oscillation) in the Alps is made with paleoecological data from North American and Scandinavia and a climate signal in the GRIP ice core from central Greenland 8200 yr ago (ca. 7400 yr uncal. BP).

  13. Climate, Environment and Early Human Innovation: Stable Isotope and Faunal Proxy Evidence from Archaeological Sites (98-59ka) in the Southern Cape, South Africa.

    Science.gov (United States)

    Roberts, Patrick; Henshilwood, Christopher S; van Niekerk, Karen L; Keene, Petro; Gledhill, Andrew; Reynard, Jerome; Badenhorst, Shaw; Lee-Thorp, Julia

    2016-01-01

    The Middle Stone Age (MSA) of southern Africa, and in particular its Still Bay and Howiesons Poort lithic traditions, represents a period of dramatic subsistence, cultural, and technological innovation by our species, Homo sapiens. Climate change has frequently been postulated as a primary driver of the appearance of these innovative behaviours, with researchers invoking either climate instability as a reason for the development of buffering mechanisms, or environmentally stable refugia as providing a stable setting for experimentation. Testing these alternative models has proved intractable, however, as existing regional palaeoclimatic and palaeoenvironmental records remain spatially, stratigraphically, and chronologically disconnected from the archaeological record. Here we report high-resolution records of environmental shifts based on stable carbon and oxygen isotopes in ostrich eggshell (OES) fragments, faunal remains, and shellfish assemblages excavated from two key MSA archaeological sequences, Blombos Cave and Klipdrift Shelter. We compare these records with archaeological material remains in the same strata. The results from both sites, spanning the periods 98-73 ka and 72-59 ka, respectively, show significant changes in vegetation, aridity, rainfall seasonality, and sea temperature in the vicinity of the sites during periods of human occupation. While these changes clearly influenced human subsistence strategies, we find that the remarkable cultural and technological innovations seen in the sites cannot be linked directly to climate shifts. Our results demonstrate the need for scale-appropriate, on-site testing of behavioural-environmental links, rather than broader, regional comparisons.

  14. A New EO-Based Indicator for Assessing and Monitoring Climate-Related Vegetation Stress

    Science.gov (United States)

    McCormick, Niall; Gobron, Nadine

    2016-08-01

    This paper describes a study in which a new environmental indicator, called Annual Vegetation Stress (AVS), has been developed, based on annual anomalies of satellite-measured Fraction of Absorbed Photosynthetically Active Radiation (FAPAR ), and used to map the area affected annually by vegetation stress during the period 2003-2014, for 108 selected developing countries. Analysis of the results for six countries in the "tropical and subtropical forests" ecoregion, reveals good correspondence between high AVS values, and the occurrence of climatic extremes (droughts) and anthropogenic disturbance (deforestation). The results for Equatorial Guinea suggest that the recent trend of large-scale droughts and rainfall deficits in Central and Western Africa, contribute to increased vegetation stress in the region's tropical rainforests. In East Timor there is evidence of a "biological lag" effect, whereby the main impacts of drought on the country's seasonally dry tropical forests are delayed until the year following the climate event.

  15. Extreme warming challenges sentinel status of kelp forests as indicators of climate change

    Science.gov (United States)

    Reed, Daniel; Washburn, Libe; Rassweiler, Andrew; Miller, Robert; Bell, Tom; Harrer, Shannon

    2016-12-01

    The desire to use sentinel species as early warning indicators of impending climate change effects on entire ecosystems is attractive, but we need to verify that such approaches have sound biological foundations. A recent large-scale warming event in the North Pacific Ocean of unprecedented magnitude and duration allowed us to evaluate the sentinel status of giant kelp, a coastal foundation species that thrives in cold, nutrient-rich waters and is considered sensitive to warming. Here, we show that giant kelp and the majority of species that associate with it did not presage ecosystem effects of extreme warming off southern California despite giant kelp's expected vulnerability. Our results challenge the general perception that kelp-dominated systems are highly vulnerable to extreme warming events and expose the more general risk of relying on supposed sentinel species that are assumed to be very sensitive to climate change.

  16. Improved spectral comparisons of paleoclimate models and observations via proxy system modeling: Implications for multi-decadal variability

    Science.gov (United States)

    Dee, S. G.; Parsons, L. A.; Loope, G. R.; Overpeck, J. T.; Ault, T. R.; Emile-Geay, J.

    2017-10-01

    The spectral characteristics of paleoclimate observations spanning the last millennium suggest the presence of significant low-frequency (multi-decadal to centennial scale) variability in the climate system. Since this low-frequency climate variability is critical for climate predictions on societally-relevant scales, it is essential to establish whether General Circulation models (GCMs) are able to simulate it faithfully. Recent studies find large discrepancies between models and paleoclimate data at low frequencies, prompting concerns surrounding the ability of GCMs to predict long-term, high-magnitude variability under greenhouse forcing (Laepple and Huybers, 2014a, 2014b). However, efforts to ground climate model simulations directly in paleoclimate observations are impeded by fundamental differences between models and the proxy data: proxy systems often record a multivariate and/or nonlinear response to climate, precluding a direct comparison to GCM output. In this paper we bridge this gap via a forward proxy modeling approach, coupled to an isotope-enabled GCM. This allows us to disentangle the various contributions to signals embedded in ice cores, speleothem calcite, coral aragonite, tree-ring width, and tree-ring cellulose. The paper addresses the following questions: (1) do forward-modeled ;pseudoproxies; exhibit variability comparable to proxy data? (2) if not, which processes alter the shape of the spectrum of simulated climate variability, and are these processes broadly distinguishable from climate? We apply our method to representative case studies, and broaden these insights with an analysis of the PAGES2k database (PAGES2K Consortium, 2013). We find that current proxy system models (PSMs) can help resolve model-data discrepancies on interannual to decadal timescales, but cannot account for the mismatch in variance on multi-decadal to centennial timescales. We conclude that, specific to this set of PSMs and isotope-enabled model, the paleoclimate

  17. Variations in the width of the Indo-Pacific tropical rain belt over the last millennium: synthesis of stalagmite proxy records and climate model simulations

    Science.gov (United States)

    Ummenhofer, Caroline; Denniston, Rhawn

    2017-04-01

    The seasonal north-south migration of the intertropical convergence zone defines the tropical rain belt (TRB), a region of enormous terrestrial biodiversity and home to 40% of the world's population. The TRB is dynamic and has been shown to shift south as a coherent system during periods of Northern Hemisphere cooling. However, recent studies of Indo-Pacific hydroclimate suggest that during the Little Ice Age (AD 1400-1850), the TRB in this region contracted rather than being displaced uniformly southward. This behaviour is not well understood, particularly during climatic fluctuations less pronounced than those of the Little Ice Age, the largest centennial-scale cool period of the last millennium. Using state-of-the-art climate model simulations conducted as part of the Last Millennium Ensemble with the Community Earth System Model (CESM), we evaluate variations in the width of the Indo-Pacific TRB, as well as movements in the position of its northward and southward edges, across a range of timescales over the pre-Industrial portion of the last millennium (AD 850-1850). The climate model results complement a recent reconstruction of late Holocene variability of the Indo-Pacific TRB, based on a precisely-dated, monsoon-sensitive stalagmite reconstruction from northern Australia (cave KNI-51), located at the southern edge of the TRB and thus highly sensitive to variations at its southern edge. Integrating KNI-51 with a record from Dongge Cave in southern China allows a stalagmite-based TRB reconstruction. Our results reveal that rather than shifting meridionally, the Indo-Pacific TRB expanded and contracted over multidecadal/centennial time scales during the late Holocene, with symmetric weakening/strengthening of summer monsoons in the Northern and Southern Hemispheres of the Indo-Pacific (the East Asian summer monsoon in China and the Australian summer monsoon in northern Australia). Links to large-scale climatic conditions across the Indo-Pacific region

  18. Theropod fauna from southern Australia indicates high polar diversity and climate-driven dinosaur provinciality.

    Science.gov (United States)

    Benson, Roger B J; Rich, Thomas H; Vickers-Rich, Patricia; Hall, Mike

    2012-01-01

    The Early Cretaceous fauna of Victoria, Australia, provides unique data on the composition of high latitude southern hemisphere dinosaurs. We describe and review theropod dinosaur postcranial remains from the Aptian-Albian Otway and Strzelecki groups, based on at least 37 isolated bones, and more than 90 teeth from the Flat Rocks locality. Several specimens of medium- and large-bodied individuals (estimated up to ~8.5 metres long) represent allosauroids. Tyrannosauroids are represented by elements indicating medium body sizes (~3 metres long), likely including the holotype femur of Timimus hermani, and a single cervical vertebra represents a juvenile spinosaurid. Single specimens representing medium- and small-bodied theropods may be referrable to Ceratosauria, Ornithomimosauria, a basal coelurosaur, and at least three taxa within Maniraptora. Thus, nine theropod taxa may have been present. Alternatively, four distinct dorsal vertebrae indicate a minimum of four taxa. However, because most taxa are known from single bones, it is likely that small-bodied theropod diversity remains underestimated. The high abundance of allosauroids and basal coelurosaurs (including tyrannosauroids and possibly ornithomimosaurs), and the relative rarity of ceratosaurs, is strikingly dissimilar to penecontemporaneous dinosaur faunas of Africa and South America, which represent an arid, lower-latitude biome. Similarities between dinosaur faunas of Victoria and the northern continents concern the proportional representatation of higher clades, and may result from the prevailing temperate-polar climate of Australia, especially at high latitudes in Victoria, which is similar to the predominant warm-temperate climate of Laurasia, but distinct from the arid climate zone that covered extensive areas of Gondwana. Most dinosaur groups probably attained a near-cosmopolitan distribution in the Jurassic, prior to fragmentation of the Pangaean supercontinent, and some aspects of the hallmark

  19. Theropod Fauna from Southern Australia Indicates High Polar Diversity and Climate-Driven Dinosaur Provinciality

    Science.gov (United States)

    Benson, Roger B. J.; Rich, Thomas H.; Vickers-Rich, Patricia; Hall, Mike

    2012-01-01

    The Early Cretaceous fauna of Victoria, Australia, provides unique data on the composition of high latitude southern hemisphere dinosaurs. We describe and review theropod dinosaur postcranial remains from the Aptian–Albian Otway and Strzelecki groups, based on at least 37 isolated bones, and more than 90 teeth from the Flat Rocks locality. Several specimens of medium- and large-bodied individuals (estimated up to ∼8.5 metres long) represent allosauroids. Tyrannosauroids are represented by elements indicating medium body sizes (∼3 metres long), likely including the holotype femur of Timimus hermani, and a single cervical vertebra represents a juvenile spinosaurid. Single specimens representing medium- and small-bodied theropods may be referrable to Ceratosauria, Ornithomimosauria, a basal coelurosaur, and at least three taxa within Maniraptora. Thus, nine theropod taxa may have been present. Alternatively, four distinct dorsal vertebrae indicate a minimum of four taxa. However, because most taxa are known from single bones, it is likely that small-bodied theropod diversity remains underestimated. The high abundance of allosauroids and basal coelurosaurs (including tyrannosauroids and possibly ornithomimosaurs), and the relative rarity of ceratosaurs, is strikingly dissimilar to penecontemporaneous dinosaur faunas of Africa and South America, which represent an arid, lower-latitude biome. Similarities between dinosaur faunas of Victoria and the northern continents concern the proportional representatation of higher clades, and may result from the prevailing temperate–polar climate of Australia, especially at high latitudes in Victoria, which is similar to the predominant warm–temperate climate of Laurasia, but distinct from the arid climate zone that covered extensive areas of Gondwana. Most dinosaur groups probably attained a near-cosmopolitan distribution in the Jurassic, prior to fragmentation of the Pangaean supercontinent, and some aspects of the

  20. Site-dependent proxy response to climate change during the last 140 years observed in varved lake sediments in Northern Poland

    Science.gov (United States)

    Ott, Florian; Kramkowski, Mateusz; Wulf, Sabine; Plessen, Birgit; Serb, Johanna; Tjallingii, Rik; Schwab, Markus; Słowiński, Michał; Brykała, Dariusz; Tyszkowski, Sebastian; Putyrskaya, Victoria; Appelt, Oona; Błaszkiewicz, Mirosław; Brauer, Achim

    2017-04-01

    This accurate dating and chronological correlation using crypto-tephras provide a powerful way to compare the varved sediment records of the lakes Głęboczek (JG), Czechowskie (JC) and Jelonek (JEL) (north-central Poland). For the last 140 years, high-resolution varve micro-facies analyses (seasonal layer composition and thickness) and µ-XRF element scanning as well as bulk geochemical analyses (TOC, CaCO3) at sub-decadal to decadal resolution were conducted for all three records. Varve chronologies have been independently established by means of annual layer counting. 137Cs activity concentration measurements confirmed the varve chronology from JC. The Askja AD1875 tephra has been used to synchronize the records. A comparison of sediment data with monthly temperature data from Koszalin since 1870 and daily temperature data from Chojnice since 1951 revealed different responses of lake deposition to recent temperature change. Varves are well-preserved over the entire 140 years only in the sediments of JG, while in the JC record two faintly varved intervals are intercalated and in JEL two non-varved intervals occur at the base and top of the profile. These differences likely are due to variations in lake characteristics. Climate changes at the demise of the Little Ice Age and the recent warming since the 1980s are expressed in varve micro-facies, CaCO3 and TOC contents in the three lakes with different response times and amplitudes. This allows us to discuss the role of local parameters like lake size, bathymetry and water depth in transferring climate change signals into lake sediment records. This study is a contribution to the Virtual Institute of Integrated Climate and Landscape Evolution Analyses - ICLEA - of the Helmholtz Association, grant number VH-VI-415.

  1. Unveiling exceptional Baltic bog ecohydrology, autogenic succession and climate change during the last 2000 years in CE Europe using replicate cores, multi-proxy data and functional traits of testate amoebae

    Science.gov (United States)

    Gałka, Mariusz; Tobolski, Kazimierz; Lamentowicz, Łukasz; Ersek, Vasile; Jassey, Vincent E. J.; van der Knaap, Willem O.; Lamentowicz, Mariusz

    2017-01-01

    We present the results of high-resolution, multi-proxy palaeoecological investigations of two parallel peat cores from the Baltic raised bog Mechacz Wielki in NE Poland. We aim to evaluate the role of regional climate and autogenic processes of the raised bog itself in driving the vegetation and hydrology dynamics. Based on partly synchronous changes in Sphagnum communities in the two study cores we suggest that extrinsic factors (climate) played an important role as a driver in mire development during the bog stage (500-2012 CE). Using a testate amoebae transfer function, we found exceptionally stable hydrological conditions during the last 2000 years with a relatively high water table and lack of local fire events that allowed for rapid peat accumulation (2.75 mm/year) in the bog. Further, the strong correlation between pH and community-weighted mean of testate amoeba traits suggests that other variables than water-table depth play a role in driving microbial properties under stable hydrological conditions. There is a difference in hydrological dynamics in bogs between NW and NE Poland until ca 1500 CE, after which the water table reconstructions show more similarities. Our results illustrate how various functional traits relate to different environmental variables in a range of trophic and hydrological scenarios on long time scales. Moreover, our data suggest a common regional climatic forcing in Mechacz Wielki, Gązwa and Kontolanrahka. Though it may still be too early to attempt a regional summary of wetness change in the southern Baltic region, this study is a next step to better understand the long-term peatland palaeohydrology in NE Europe.

  2. An automated system for access to derived climate indices in support of ecological impacts assessments and resource management

    Science.gov (United States)

    Walker, J.; Morisette, J. T.; Talbert, C.; Blodgett, D. L.; Kunicki, T.

    2012-12-01

    A U.S. Geological Survey team is working with several providers to establish standard data services for the climate projection data they host. To meet the needs of climate adaptation science and landscape management communities, the team is establishing a set of climate index calculation algorithms that will consume data from various providers and provide directly useful data derivatives. Climate projections coming from various scenarios, modeling centers, and downscaling methods are increasing in number and size. Global change impact modeling and assessment, generally, requires inputs in the form of climate indices or values derived from raw climate projections. This requirement puts a large burden on a community not familiar with climate data formats, semantics, and processing techniques and requires storage capacity and computing resources out of the reach of most. In order to fully understand the implications of our best available climate projections, assessments must take into account an ensemble of climate projections and potentially a range of parameters for calculation of climate indices. These requirements around data access and processing are not unique from project to project, or even among projected climate data sets, pointing to the need for a reusable tool to generate climate indices. The U.S. Geological Survey has developed a pilot application and supporting web service framework that automates the generation of climate indices. The web service framework consists of standards-based data servers and a data integration broker. The resulting system allows data producers to publish and maintain ownership of their data and data consumers to access climate derivatives via a simple to use "data product ordering" workflow. Data access and processing is completed on enterprise "cloud" computing resources and only the relatively small, derived climate indices are delivered to the scientist or land manager. These services will assist the scientific and land

  3. Climate for a transport change. TERM 2007: indicators tracking transport and environment in the European Union

    Energy Technology Data Exchange (ETDEWEB)

    2008-03-15

    This report represents a summary of selected issues from the European Environment Agency Transport and Environment Reporting Mechanism (EEA-TERM) set of transport and environment integration indicators. The objective of this report is to indicate some of the main challenges to reducing the environmental impacts of transport and to make suggestions to improve the environmental performance of the transport system as a whole. The report examines issues centred around transport and climate change, which need to be addressed in the coming years. These issues are derived partly from the policy questions that form the backbone of TERM and partly from other ongoing work at EEA. As with previous TERM reports, this report evaluates the indicator trends with respect to progress towards existing objectives and targets from EU policy documents and various transport and environmental directives. The selection does not represent a full inventory of conclusions that can be extracted from TERM but rather a selection that tries to give deeper insight into the link between transport development and climate change. Readers are therefore encouraged to seek further information in the TERM fact sheets themselves (see link below), as well as in other sources referred to. (au)

  4. Correlation of Ice-Rafted Detritus in South Atlantic Sediments with Climate Proxies in Polar Ice over the Last Glacial Period

    Directory of Open Access Journals (Sweden)

    Sharon L. Kanfoush

    2013-03-01

    Full Text Available Previous study identified 6–7 millennial-scale episodes of South Atlantic ice-rafted sediment deposition (SA events during the glaciation. Questions remain, however, regarding their origin, significance for sea-ice and/or Antarctic ice-sheet dynamics, and relationship to climate. Here I correlate sediment core (TTN057–21 SA events to Greenland and Antarctic ice using two independent methods, stable isotopes and geomagnetic paleointensity, placing SA events in the context of polar climate change in both hemispheres. Marine isotopic stage (MIS 3 SA events generally coincided with Greenland interstadials and with cooling following Antarctic warm events (A1-A4. This anti-phase behavior is best illustrated when SA0 coincided with both the Antarctic Cold Reversal and Bolling-Allerod warming in Greenland. Moreover, SA events coincide with sea-level rises during the deglaciation (mwp1A and MIS 3 (30.4, 38.3, 43.7, 51.5 ka, implying unpinning of grounded Weddell Sea region ice masses discharged debris-laden bergs that had a chilling effect on South Atlantic surface temperatures.

  5. Reliability of temperature signal in various climate indicators from northern Europe.

    Directory of Open Access Journals (Sweden)

    Pertti Hari

    Full Text Available We collected relevant observational and measured annual-resolution time series dealing with climate in northern Europe, focusing in Finland. We analysed these series for the reliability of their temperature signal at annual and seasonal resolutions. Importantly, we analysed all of the indicators within the same statistical framework, which allows for their meaningful comparison. In this framework, we employed a cross-validation procedure designed to reduce the adverse effects of estimation bias that may inflate the reliability of various temperature indicators, especially when several indicators are used in a multiple regression model. In our data sets, timing of phenological observations and ice break-up were connected with spring, tree ring characteristics (width, density, carbon isotopic composition with summer and ice formation with autumn temperatures. Baltic Sea ice extent and the duration of ice cover in different watercourses were good indicators of winter temperatures. Using combinations of various temperature indicator series resulted in reliable temperature signals for each of the four seasons, as well as a reliable annual temperature signal. The results hence demonstrated that we can obtain reliable temperature information over different seasons, using a careful selection of indicators, combining the results with regression analysis, and by determining the reliability of the obtained indicator.

  6. Regional climate change trends and uncertainty analysis using extreme indices: A case study of Hamilton, Canada

    Directory of Open Access Journals (Sweden)

    Tara Razavi

    2016-01-01

    All climate models predicted increasing trends for extreme temperature indices, maximum 1-day and 5-day precipitation (RX1day and RX5day, total wet day precipitation (PRCPTOT, very heavy precipitation days (R20mm, Summer Days (SU, and Tropical Nights (TR and decreasing trend for Forest Days (FD and Ice Days (ID in 2020s, 2050s, and 2080s compared to present. CanRCM4 model did consistently project values in the upper range of the CMIP5 ensemble while the PRECIS ensemble was more in-line with the CMIP5 mean values. This difference may however be a function of different emission scenarios used.

  7. Climate change impacts on faecal indicator and waterborne pathogen concentrations and disease

    Science.gov (United States)

    Hofstra, Nynke; Vermeulen, Lucie C.; Wondmagegn, Berhanu Y.

    2013-04-01

    Changes in temperature and precipitation patterns may impact on the concentrations of the faecal indicator E. coli and waterborne pathogens, such as Cryptosporidium, in the surface water, and consequently - through drinking water, recreational water or consumption of irrigated vegetables - on the risk of waterborne disease. Although an increased temperature would generally increase the decline of pathogens and therefore decrease the surface water concentrations, increased precipitation and an increased incidence of extreme precipitation may increase surface water concentrations through increased (sub-)surface runoff and an increased risk of sewer overflows. And while the diluting effect of increased precipitation decreases the surface water concentration, decreased precipitation increases the percentage of sewage in the surface water and therefore increases the concentration. Moreover, (extreme) precipitation after drought may also increase the concentration. Changes in behaviour, such as increased recreation and irrigation with higher temperatures may impact on the disease risk. What the balance is between these positive and negative impacts of climate change on faecal indicator and waterborne pathogen concentrations and disease is not well known yet. A lack of available statistical or process-based models and suitable scenarios prevents quantitative analyses. We will present two examples of recent studies that aim to assess the impact of climate change on faecal indicator concentrations and waterborne disease. The first is a study on the relationship between climate variables and E. coli concentrations in the water of river systems in the Netherlands for the period 1985 - 2010. This study shows that each of the variables water temperature (negatively), precipitation and discharge (both positively) are significantly correlated with E. coli concentrations for most measurement locations. We will also present a linear regression model, including all of these

  8. A big data approach for climate change indicators processing in the CLIP-C project

    Science.gov (United States)

    D'Anca, Alessandro; Conte, Laura; Palazzo, Cosimo; Fiore, Sandro; Aloisio, Giovanni

    2016-04-01

    Defining and implementing processing chains with multiple (e.g. tens or hundreds of) data analytics operators can be a real challenge in many practical scientific use cases such as climate change indicators. This is usually done via scripts (e.g. bash) on the client side and requires climate scientists to take care of, implement and replicate workflow-like control logic aspects (which may be error-prone too) in their scripts, along with the expected application-level part. Moreover, the big amount of data and the strong I/O demand pose additional challenges related to the performance. In this regard, production-level tools for climate data analysis are mostly sequential and there is a lack of big data analytics solutions implementing fine-grain data parallelism or adopting stronger parallel I/O strategies, data locality, workflow optimization, etc. High-level solutions leveraging on workflow-enabled big data analytics frameworks for eScience could help scientists in defining and implementing the workflows related to their experiments by exploiting a more declarative, efficient and powerful approach. This talk will start introducing the main needs and challenges regarding big data analytics workflow management for eScience and will then provide some insights about the implementation of some real use cases related to some climate change indicators on large datasets produced in the context of the CLIP-C project - a EU FP7 project aiming at providing access to climate information of direct relevance to a wide variety of users, from scientists to policy makers and private sector decision makers. All the proposed use cases have been implemented exploiting the Ophidia big data analytics framework. The software stack includes an internal workflow management system, which coordinates, orchestrates, and optimises the execution of multiple scientific data analytics and visualization tasks. Real-time workflow monitoring execution is also supported through a graphical user

  9. Soil Crystallinity As a Climate Indicator: Field Experiments on Earth and Mars

    Science.gov (United States)

    Horgan, Briony; Scudder, Noel; Rampe, Elizabeth; Rutledge, Alicia

    2016-01-01

    Soil crystallinity is largely determined by leaching rates, as high leaching rates favor the rapid precipitation of short order or poorly-crystalline phases like the aluminosilicate allophane. High leaching rates can occur due to high precipitation rates, seasonal monsoons, or weathering of glass, but are also caused by the rapid onset of seasonal melting of snow and ice in cold environments. Thus, cold climate soils are commonly dominated by poorly crystalline phases, which mature into kaolin minerals over time. Thus, we hypothesize that, in some contexts, soils with high abundances of poorly crystalline phases could indicate formation under cold climatic conditions. This model could be helpful in interpreting the poorly-constrained paleoclimate of ancient Mars, as the crystallinity of ancient soils and soil-derived sediments appears to be highly variable in time and space. While strong signatures of crystalline phyllosilicates have been identified in possible ancient paleosols on Mars, Mars Science Laboratory rover investigations of diverse ancient sediments at Gale Crater has shown that they can contain very high abundances (40-50 wt%) of poorly crystalline phases. We hypothesize that these poorly crystalline phases could be the result of weathering by ice/snow melt, perhaps providing support for sustained cold climates on early Mars punctuated by more limited warm climates. Furthermore, such poorly crystalline soils could be highly fertile growth media for future human exploration and colonization on Mars. To test this hypothesis, we are currently using rover-like instrumentation to investigate the mineralogy and chemistry of weathering products generated by snow and ice melt in a Mars analog alpine environment: the glaciated Three Sisters volcanic complex in central Oregon. Alteration in this glacial environment generates high abundances of poorly crystalline phases, many of which have compositions distinct from those identified in previous terrestrial

  10. Plant phenological water cycle and implications for using δ2H-alkanes as paleo proxy in a semi-arid tropical climate

    Science.gov (United States)

    De Wispelaere, Lien; Bodé, Samuel; Hervé-Fernández, Pedro; Hemp, Andreas; Verschuren, Dirk; Boeckx, Pascal

    2017-04-01

    Lake Challa is a steep-sided crater lake situated in equatorial East Africa, a tropical semi-arid area with bimodal rainfall pattern. The δ2H and δ18O of precipitation, lake water, groundwater, plant xylem water and plant leaf water were measured across different plant species, seasons and plant habitats in the vicinity of Lake Challa, as well as the hydrogen-isotopic composition of leaf wax n-alkanes (δ2Hwax). Long chain n-alkanes of terrestrial plant leaf waxes provide information on plant-water relations and have been widely used as proxy in paleoclimate and paleovegetation reconstructions. In our study, we found that plants rely mostly on water from the 'short rains' falling from October till December (northeast monsoon), as these recharge the soil pores after the long dry season. This plant-available, static, water pool is only slightly replenished by the 'long rains' falling from February to May (southeast monsoon), in agreement with the 'two water world' hypothesis according to which plants rely on a static water pool separated from a more mobile water pool that recharges the groundwater. Spatial variability in water resource use exists in the study region with plants at the lakeshore relying on water of different isotopic composition, i.e isotopically evaporated lake water at the lakeshore vs. non- or slightly evaporated precipitation in the savannah and on the crater rim. This spatial resource partitioning is recorded by elevated δ2H values in the leaf wax lipids of plants at the lakeshore. The distribution of n-alkanes in the fresh leaves shows a unimodal distribution pattern reaching a maximum at n-C29 and n-C31 for both shrubs and trees, while C4 grasses are dominated by n-C31. However, the relative abundance of n-C31 was higher at the lakeshore compared to the savannah and crater rim (when grasses were not included). According to our results, plant species and their associated leaf phenology are the primary factors influencing the enrichment in

  11. Proxy Smart Card Systems

    OpenAIRE

    Cattaneo, Giuseppe; Faruolo, Pompeo; Palazzo, Vincenzo; Visconti, Ivan

    2010-01-01

    International audience; The established legal value of digital signatures and the growing availability of identity-based digital services are progressively extending the use of smart cards to all citizens, opening new challenging scenarios. Among them, motivated by concrete applications, secure and practical delegation of digital signatures is becoming more and more critical. Unfortunately, secure delegation systems proposed so far (e.g., proxy signatures) include various drawbacks for any pr...

  12. Comparing proxy and model estimates of hydroclimate variability and change over the Common Era

    Science.gov (United States)

    Hydro2k Consortium, Pages

    2017-12-01

    Water availability is fundamental to societies and ecosystems, but our understanding of variations in hydroclimate (including extreme events, flooding, and decadal periods of drought) is limited because of a paucity of modern instrumental observations that are distributed unevenly across the globe and only span parts of the 20th and 21st centuries. Such data coverage is insufficient for characterizing hydroclimate and its associated dynamics because of its multidecadal to centennial variability and highly regionalized spatial signature. High-resolution (seasonal to decadal) hydroclimatic proxies that span all or parts of the Common Era (CE) and paleoclimate simulations from climate models are therefore important tools for augmenting our understanding of hydroclimate variability. In particular, the comparison of the two sources of information is critical for addressing the uncertainties and limitations of both while enriching each of their interpretations. We review the principal proxy data available for hydroclimatic reconstructions over the CE and highlight the contemporary understanding of how these proxies are interpreted as hydroclimate indicators. We also review the available last-millennium simulations from fully coupled climate models and discuss several outstanding challenges associated with simulating hydroclimate variability and change over the CE. A specific review of simulated hydroclimatic changes forced by volcanic events is provided, as is a discussion of expected improvements in estimated radiative forcings, models, and their implementation in the future. Our review of hydroclimatic proxies and last-millennium model simulations is used as the basis for articulating a variety of considerations and best practices for how to perform proxy-model comparisons of CE hydroclimate. This discussion provides a framework for how best to evaluate hydroclimate variability and its associated dynamics using these comparisons and how they can better inform

  13. Pacific decadal climate variability: Indices, patterns and tropical-extratropical interactions

    Science.gov (United States)

    Henley, Benjamin J.

    2017-08-01

    Pacific decadal variability (PDV) plays a critical role in the climate system. Here I present a review of indices and patterns of decadal climate variability in the Pacific from observations and palaeoclimate reconstructions. I examine the spatial characteristics of Pacific sea surface temperature variability and the metrics used to track observations of PDV. I find commonalities between the PDV patterns, the Interdecadal Pacific Oscillation (IPO) and its North and South Pacific counterparts, the Pacific Decadal and South Pacific Decadal Oscillations (PDO and SPDO). I present a tool to provide probabilistic quantification of the recent state of the IPO, and use the tool to provide reliable estimates of IPO state up to 2 years prior to the present. The tool indicates a probability of 80-90% that the IPO remained in its negative state until 2014-2015. I review palaeoclimate reconstructions of the IPO and PDO, and outline advances and challenges in our pre-instrumental understanding of PDV. I draw attention to a Pacific-wide tropical-extratropical mechanism that suggests that the cool and warm phases of PDV are not driven by tropical or extratropical variability alone, but are instead the result of continuous tropical-extratropical interactions on decadal timescales. I conclude by noting key sources of remaining uncertainty and emphasising the need to better understand decadal variability. This will occur through continual improvements in observations, an expansion of palaeoclimate exploration and data collection, and renewed efforts in model development.

  14. An Advanced Review of the Relationships between Sahel Precipitation and Climate Indices: A Wavelet Approach

    Directory of Open Access Journals (Sweden)

    Churchill Okonkwo

    2014-01-01

    Full Text Available The interannual and decadal to multidecadal variability of precipitation in western Sahel region was examined using wavelet transform and coherency analysis. The aim was to identify the major climate index that has a robust relationship with Sahel precipitation (drought. The results show that ENSO, North Atlantic Oscillation (NAO, Atlantic Multidecadal Oscillation (AMO, and Indian Ocean Dipole (IOD all have some relationship with precipitation at different time scales which is in agreement with recent studies. There is an antiphase relationship between Sahel precipitation and ENSO at the 3-4-year band localized around 1982/83 El Niño episode. This indicates a cause and effect relationship between the droughts of 1983 and 1982/83 El Niño. In addition, wavelet transform coherence analysis also revealed a relatively antiphase relationship between AMO and precipitation signifying cause and effect. The wavelet analyses indicate that IOD control on rainfall variability in Sahel is limited to the east (15°E–35°E. Advancing this understanding of variability in rainfall and climate forcing could improve the accuracy of rainfall forecast.

  15. 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.

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

    Science.gov (United States)

    Paulo, A. A.; Rosa, R. D.; Pereira, L. S.

    2012-05-01

    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.

  17. Climate change and indicators of probable shifts in the consumption portfolios of dryland farmers in Sub-Saharan Africa

    NARCIS (Netherlands)

    Amjath-Babu, T.S.; Krupnik, Timothy J.; Aravindakshan, Sreejith; Arshad, Muhammad; Kaechele, Harald

    2016-01-01

    Several studies estimate the immediate impact of climate change on agricultural societies in terms of changes in crop yields or farm income, though few studies concentrate on the immediate secondary consequences of climate change. This synthetic analysis uses a set of indicators to assess the

  18. Development of New Snowstorm Indices and Databases at the National Climatic Data Center

    Science.gov (United States)

    Squires, M. F.; Lawrimore, J. H.; Heim, R. R.; Robinson, D. A.; Gerbush, M.; Estilow, T.; Tabor, C.; Wilson, A.

    2009-12-01

    NOAA’s National Climatic Data Center (NCDC) is collaborating with Rutgers University to develop a new suite of regional and national snowstorm indices. The indices use the area of snowfall, amount of snowfall, population affected by snowfall, and the juxtaposition of these elements to define an index that attempts to measure a snowstorm’s impact on society. Indices are computed for the 50 largest storms in each of six regions in the eastern two-thirds of the nation to allow current storms to be put into a century-scale historical perspective. These indices are being produced experimentally for the 2009-2010 winter season. In addition to the indices, a GIS Snowstorm Database is also being developed which will contain snowstorms from 1900 to the present stored in various GIS formats. Users will be able to map individual snowstorms, extract information about societal impacts, or use the GIS data in other research or applications. The snowstorm database will be a collection of GIS layers and tabular information for the largest 100-200 snowstorms since 1900. Each storm contains both vector and raster GIS layers with information about snowfall, transportation, schools, and hospitals. There is also tabular data that summarize societal impact information across all storms.

  19. Deciphering dynamical proxy responses from lake sediments

    Science.gov (United States)

    Ramisch, Arne; Tjallingii, Rik; Hartmann, Kai; Brauer, Achim; Diekmann, Bernhard; Haberzettl, Torsten; Kasper, Thomas; Ahlborn, Marieke

    2017-04-01

    Lakes form a reliable archive of paleoenvironmental change in the terrestrial realm. Non-destructive XRF scans provide high-resolution records of element concentrations that are commonly related to past environmental change. However, XRF records of lake sediments enclose paleoenvironmental information that originates from multiple lake external and internal forcing. The variety of environmental forcing factors can complicate a direct identification of single mechanisms like climatic change from XRF or other proxy records. Here we present XRF records from several Asian lake archives, which indicate asynchronous variations of similar geochemical records since the late glacial/early Holocene. All XRF time series are characterized by damped harmonic oscillations of relative element concentrations through time. The asynchronous variations can be expressed by the frequency and the rate of damping of theses oscillations that differ between the lakes. We argue that the oscillatory behavior is a result of a feedback between the physical removal and dissolution of mineral phases in catchment soils and their subsequent enrichment and deposition within the lake. We present a numerical model, which accurately simulates major Holocene variations in the element concentration of lake records and discuss implications for the reconstruction of environmental signals from lake sediments.

  20. Past environmental/climatic changes in the northern part of the South China Sea, input from multi-proxy analysis of core MD12-3432

    Science.gov (United States)

    Chen, Quan; Kissel, Catherine; Liu, Zhifei

    2017-04-01

    In the South China Sea, the magnetic component of marine sediment is a powerful recorder of paleoenvironmental changes linked to the regional and global climate. Based on the knowledge of the sedimentary signature of the potential sources for terrigenous sediments, the composition of marine sediments can be used to decipher the different mechanisms, forcing, and transport vectors. We report here the analysis of the magnetic properties combined with sortable silt and clay mineralogy of a 51 m long sedimentary sequence retrieved from the northern South China Sea and covering the last 400 ka. Magnetic minerals with different coercivities (magnetite, pyrrhotite and hematite) are mixed in the sequence and their relative concentration varies with time. Glacial low sea-levels reduce the land-site distance and they are illlustrated by higher concentrations in magnetites and iron-sulfides (pyrrhotite) related to the sediments previously deposited on the continental shelf and re-worked by the river. This is accompanied by increasing kaolinite content within the clay assemblage (Pearl River signature) and by coarser grains. Superimposed to this eccentricity periodicity, hematite content and smectite/(illite+chlorite) ratio present a predominant precession periodicity synchronous with the northern hemisphere summer insolation changes and therefore with that of the East Asian summer monsoon. Events of high hematite content, in phase with finer grains, coincide with precession lows, while smectite/(illite+chlorite) ratio is maximum during precession highs. Knowing that smectite is mainly produced by contemporaneous chemical weathering intensity in Luzon, we use the smectite/(illite+chlorite) ratio as a tracer for increasing weathering rate in Luzon, in turn related to enhanced East Asian summer monsoon. Hematite is not produced in large amount on adjacent lands and its association with fine sediment grains suggests that its periodic supply is related to the eolian dust

  1. Development of a Water Clarity Index for the Southeastern U.S. As a Climate Indicator

    Science.gov (United States)

    Sheridan, S. C.; Hu, C.; Lee, C. C.; Barnes, B.; Pirhalla, D.; Ransi, V.; Shein, K. A.

    2014-12-01

    A common index of water quality is water clarity, which can be estimated by measuring the diffuse attenuation coefficient for downwelling irradiance (Kd). Kd estimates the availability of light to marine organisms at various depths. Marine habitats, including such species as coral and seagrass, can be negatively affected by extreme episodes of sediment suspension, where water clarity is reduced and little light penetrates. Evidence of increased stress on coastal ecosystems exists, partially due to climate change, yet a systematic analysis of extreme events and trends is difficult due to limited data. To address this concern, we have developed as a potential climate indicator a Kd-Index for nine regions along the US coast of the Gulf of Mexico, in which Kd values have been standardized over time and space to allow for a more holistic assessment of climate drivers and their trends. Variability in the Kd-Index is then assessed with regard to occurrences of surface weather types (using the Spatial Synoptic Classification), a synoptic climatology of mean sea-level-pressure patterns across the region, along with heavy precipitation events. Kd can be estimated from MODIS and SeaWiFS observations from 1997 to date; an earlier period of satellite observations from 1978-86 is also available. A non-linear autoregressive neural network model with external input (NARX) is used to develop the historical relationship between Kd-Index and atmospheric conditions, and then this model is used to simulate a full time series from 1948 to 2013. The modeled data set is strongly correlated with observations, with correlations above 0.8 for many regions. Hit rates of extreme Kd-Index values - those which would most likely be associated with a negative environmental impact - exceed 70% in some regions. Across the full data set, long term trends vary slightly across regions but are generally small. Trends in extreme events appear to be more consistently increasing across the domain.

  2. The Effect of Body Weight on Heat Strain Indices in Hot and Dry Climatic Conditions

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    Habibi

    2016-03-01

    Full Text Available Background Being overweight is a characteristic that may influence a person’s heat exchange. Objectives The purpose of this study was to assess the effect of body weight on heat strain indices in hot and dry climatic conditions. Materials and Methods This study was completed with a sample of 30 participants with normal weights, as well as 25 participants who were overweight. The participants were physically inactive for a period of 120 minutes in a climatic chamber with hot and dry conditions (22 - 32°C and with 40% relative humidity (RH.The physiological strain index (PSI and heat strain score index (HSSI questionnaires were used. Simultaneous measurements were completed during heat exposure for periods of five minutes. The resting periods acted as the initial measurements for 15 minutes. Results In both groups, oral temperature, heart rate, and thermal perceptual responses increased during heat exposure. The means and standard deviations of heart rate and oral temperature were gathered when participants were in hot and dry climatic conditions and were not physically active. The heart rates and oral temperatures were 79.21 ± 5.93 bpm and 36.70 ± 0.45°C, respectively, for those with normal weights. For overweight individuals, the measurements for heart rate and oral temperature reached 82.21 ± 8.9 bpm and 37.84 ± 0.37°C, respectively. Conclusions The results showed that, compared to participants with normal weights, physiological and thermal perceptual responses were higher in overweight participants. Therefore, overweight individuals should avoid hot/dry weather conditions to decrease the amount of heat strain.

  3. THE USE OF CATEGORIES AS INDICATORS OF ORGANIZATIONAL CLIMATE IN BRAZILIAN COMPANIES

    Directory of Open Access Journals (Sweden)

    Joel Souza Dutra

    2012-04-01

    Full Text Available In order to analyze employees’ perception of the work environment, companies with a well-established people management structure periodically conduct organizational climate surveys. These surveys are meant to offer an understanding of how employees view the quality of the relationships they experience in the company. One of the characteristics of this type of survey, identified both in the relevant literature and empirically in practice, is the use of categories or indicators to direct development of the research instrument, data analysis, and later intervention as needed according to the results of the survey. This article seeks to propose a categorization of organizational climate dimensions directed at the Brazilian corporate reality, analysing its internal consistency and its construct validity. To that end, we used the results of a wide-ranging data sample collected from 123,445 respondents of 491 organizations in various regions of Brazil. The proposed analysis categories – identity, satisfaction and motivation, learning and development, and leadership – were reviewed based on theories of organizational behavior and then submitted to a focus group composed of human resources professionals employed by prominent Brazilian corporations.

  4. Munchausen syndrome by proxy

    Directory of Open Access Journals (Sweden)

    Jovanović Aleksandar A.

    2005-01-01

    Full Text Available This review deals with bibliography on Munchausen syndrome by proxy (MSbP. The name of this disorder was introduced by English psychiatrist Roy Meadow who pointed to diagnostic difficulties as well as to serious medical and legal connotations of MSbP. MSbP was classified in DSM-IV among criteria sets provided for further study as "factitious disorder by proxy", while in ICD-10, though not explicitly cited, MSbP might be classified as "factitious disorders" F68.1. MSbP is a special form of abuse where the perpetrator induces somatic or mental symptoms of illness in the victim under his/her care and then persistently presents the victims for medical examinations and care. The victim is usually a preschool child and the perpetrator is the child's mother. Motivation for such pathological behavior of perpetrator is considered to be unconscious need to assume sick role by proxy while external incentives such as economic gain are absent. Conceptualization of MSbP development is still in the domain of psychodynamic speculation, its course is chronic and the prognosis is poor considering lack of consistent, efficient and specific treatment. The authors also present the case report of thirty-three year-old mother who had been abusing her nine year-old son both emotionally and physically over the last several years forcing him to, together with her, report to the police, medical and educational institutions that he had been the victim of rape, poisoning and beating by various individuals, especially teaching and medical staff. Mother manifested psychosis and her child presented with impaired cognitive development, emotional problems and conduct disorder.

  5. Lichen-based indices to quantify responses to climate and air pollution across northeastern U.S.A

    Science.gov (United States)

    Susan Will-Wolf; Sarah Jovan; Peter Neitlich; JeriLynn E. Peck; Roger Rosentreter

    2015-01-01

    Lichens are known to be indicators for air quality; they also respond to climate. We developed indices for lichen response to climate and air quality in forests across the northeastern United States of America (U.S.A.), using 218–250 plot surveys with 145–161 macrolichen taxa from the Forest Inventory and Analysis (FIA) Program of the U.S. Department of Agriculture,...

  6. Using an integrated hydrological model to estimate the usefulness of meteorological drought indices in a changing climate

    Directory of Open Access Journals (Sweden)

    D. von Gunten

    2016-10-01

    Full Text Available Droughts are serious natural hazards, especially in semi-arid regions. They are also difficult to characterize. Various summary metrics representing the dryness level, denoted drought indices, have been developed to quantify droughts. They typically lump meteorological variables and can thus directly be computed from the outputs of regional climate models in climate-change assessments. While it is generally accepted that drought risks in semi-arid climates will increase in the future, quantifying this increase using climate model outputs is a complex process that depends on the choice and the accuracy of the drought indices, among other factors. In this study, we compare seven meteorological drought indices that are commonly used to predict future droughts. Our goal is to assess the reliability of these indices to predict hydrological impacts of droughts under changing climatic conditions at the annual timescale. We simulate the hydrological responses of a small catchment in northern Spain to droughts in present and future climate, using an integrated hydrological model calibrated for different irrigation scenarios. We compute the correlation of meteorological drought indices with the simulated hydrological time series (discharge, groundwater levels, and water deficit and compare changes in the relationships between hydrological variables and drought indices. While correlation coefficients linked with a specific drought index are similar for all tested land uses and climates, the relationship between drought indices and hydrological variables often differs between present and future climate. Drought indices based solely on precipitation often underestimate the hydrological impacts of future droughts, while drought indices that additionally include potential evapotranspiration sometimes overestimate the drought effects. In this study, the drought indices with the smallest bias were the rainfall anomaly index, the reconnaissance drought index, and

  7. Open access to Water Indicators for Climate Change Adaptation: proof-of-concept for the Copernicus Climate Change Service (C3S)

    Science.gov (United States)

    Lottle, Lorna; Arheimer, Berit; Gyllensvärd, Frida; Dejong, Fokke; Ludwig, Fulco; Hutjes, Ronald; Martinez, Bernat

    2017-04-01

    Copernicus Climate Change Service (C3S) is still in the development phase and will combine observations of the climate system with the latest science to develop authoritative, quality-assured information about the past, current and future states of the climate and climate dependent sectors in Europe and worldwide. C3S will provide key indicators on climate change drivers and selected sectorial impacts. The aim of these indicators will be to support adaptation and mitigation. This presentation will show one service already operational as a proof-of-concept of this future climate service. The project "Service for Water Indicators in Climate Change Adaptation" (SWICCA) has developed a sectorial information service for water management. It offers readily available climate-impact data, for open access from the web-site http://swicca.climate.copernicus.eu/. The development is user-driven with the overall goal to speed up the workflow in climate-change adaptation of water management across Europe. The service is co-designed by consultant engineers and agencies in 15 case-studies spread out over the continent. SWICCA has an interactive user-interface, which shows maps and graphs, and facilitates data download in user-friendly formats. In total, more than 900 open dataset are given for various hydrometeorological (and a few socioeconomical) variables, model ensembles, resolutions, time-periods and RCPs. The service offers more than 40 precomputed climate impact indicators (CIIs) and transient time-series of 4 essential climate variables ECVs) with high spatial and temporal resolution. To facilitate both near future and far future assessments, SWICCA provides the indicators for different time ranges; normally, absolute values are given for a reference period (e.g. 1971-2000) and the expected future changes for different 30-year periods, such as early century (2011-2040), mid-century (2041-2070) and end-century (2071-2100). An ensemble of model results is always given to

  8. Ocean climate indicators: A monitoring inventory and plan for tracking climate change in the north-central California coast and ocean region

    Science.gov (United States)

    Duncan, Benet; Higgason, Kelley; Suchanek, Tom; Largier, John; Stachowicz, Jay; Allen, Sarah; Bograd, Steven; Breen, R.; Gellerman, Holly; Hill, Tessa; Jahncke, Jaime; Johnosn, Rebecca; Lonhart, Steve I.; Morgan, Steven; Wilkerson, Frances; Roletto, Jan

    2013-01-01

    The impacts of climate change, defined as increasing atmospheric and oceanic carbon dioxide and associated increases in average global temperature and oceanic acidity, have been observed both globally and on regional scales, such as in the North-central California coast and ocean, a region that extends from Point Arena to Point Año Nuevo and includes the Pacific coastline of the San Francisco Bay Area. Because of the high economic and ecological value of the region’s marine environment, the Gulf of the Farallones National Marine Sanctuary (GFNMS) and other agencies and organizations have recognized the need to evaluate and plan for climate change impacts. Climate change indicators can be developed on global, regional, and site-specific spatial scales, and they provide information about the presence and potential impacts of climate change. While indicators exist for the nation and for the state of California as a whole, no system of ocean climate indicators exist that specifically consider the unique characteristics of the California coast and ocean region. To that end, GFNMS collaborated with over 50 regional, federal, and state natural resource managers, research scientists, and other partners to develop a set of 2 ocean climate indicators specific to this region. A smaller working group of 13 regional partners developed monitoring goals, objectives, strategies, and activities for the indicators and recommended selected species for biological indicators, resulting in the Ocean Climate Indicators Monitoring Inventory and Plan. The working group considered current knowledge of ongoing monitoring, feasibility of monitoring, costs, and logistics in selecting monitoring activities and selected species.

  9. Temporal clustering of floods and impacts of climate indices in the Tarim River basin, China

    Science.gov (United States)

    Gu, Xihui; Zhang, Qiang; Singh, Vijay P.; Chen, Yongqin David; Shi, Peijun

    2016-12-01

    The occurrence rates of floods in Tarim River basin, the largest arid basin in China, were estimated using the Peak-over-Threshold (POT) technique. The intra-annual, seasonal and inter-annual clustering of floods was then analyzed using the Cox regression model, month frequency method and dispersion index, respectively. Possible impacts of climate indices on the occurrence rates were also investigated. Both NAO and AO are selected as significant covariates to occurrence rates of floods in Tarim River basin by Cox regression model, suggesting occurrence of flood events is not independent, but exhibits temporal clustering in intra-annual scale. On the basis of the results of the station and region-wide modeling by Cox regression model, we suggest using a model in which the rate of occurrence depends on monthly averaged NAO or AO. The Cox regression model not only can be used to assess the time-varying rate of flood occurrence, but also has the capability to forecast the predictors. Flood occurrence time and probability of exceedance are changing with climate index from negative to positive on both station and region scale. In addition, seasonal clustering of station-based floods and regional observed floods are also identified with mainly concentrating from June to August. Meanwhile, dispersion index is used to evaluate the inter-annual clustering of annual number of flood occurrences both on station and region. We found that inter-annual clustering of regional floods is more evident than that of station-based floods, indicating that regional observed flood records are generally over-dispersed with a tendency for flood events to cluster in time.

  10. Mapping the Holocene forest formations with the use of key climate indicators – heat and moisture

    Directory of Open Access Journals (Sweden)

    S. K. Farber

    2017-12-01

    Full Text Available The article deals with the methodology of mapping the Holocene forest formations on the basis of the DEM and the key indicators of the climate – heat and moisture. The work is carried out by means of GIS. The test site is located within the boundaries of the axial West Sayan district of mountain taiga forests, which ensures homogeneity of natural and climatic conditions. Stages of the method: creation of rasters on groups of absolute heights, exposures and inclinations with their subsequent combination into a single Combine raster; obtaining the regularities of spatial distribution of heat and moisture and their representation in the form of rasters (digital models; and interactive mapping of the Holocene forests with various combinations of heat and moisture. The use of Combine raster makes it possible to refuse to use any other contours as – landscape, geomorphological, forest inventory. To determine parameters of climatic boundaries of forest formations, the types of forests are linked to the heat and moisture indicators. As a result of linking, a graphic image is produced, where forest formations and their productivity are located in a certain order. The mapping technique involves creating a dBASE table with a field containing information about forest formations. The row-wise change in the records of forest formations as they move to other values of heat and moisture is performed interactively. Each next combination of heat and moisture on maps corresponds to a certain distribution of forest formations and site productivity (bonitet classes. (1900 ± 65 years ago the river valleys were treeless, flat meadows occupied meadows, and the slopes were steppes. As the hypsometric level increases, larch stands, spruce-Siberian stone pine with an admixture of larch, Siberian stone pine-larch with an admixture of fir, and the Siberian stone pine formations appear. (2200 ± 100 years ago the tundra prevailed. Larch forests of V–Va classes of

  11. Climate change, impacts and vulnerability in Europe 2012. An indicator-based report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-11-15

    This European Environment Agency (EEA) report presents information on past and projected climate change and related impacts in Europe, based on a range of indicators. The report also assesses the vulnerability of society, human health and ecosystems in Europe and identifies those regions in Europe most at risk from climate change. Furthermore, the report discusses the principle sources of uncertainty for the indicators and notes how monitoring and scenario development can improve our understanding of climate change, its impacts and related vulnerabilities. Some key findings: The last decade (2002-2011) was the warmest on record in Europe, with European land temperature 1.3 deg. C warmer than the pre-industrial average. Various model projections show that Europe could be 2.5-4 deg. C warmer in the later part of the 21st Century, compared to the 1961-1990 average. Heat waves have increased in frequency and length, causing tens of thousands of deaths over the last decade. The projected increase in heat waves could increase the number of related deaths over the next decades, unless societies adapt, the report says. However, cold-related deaths are projected to decrease in many countries. While precipitation is decreasing in southern regions, it is increasing in northern Europe, the report says. These trends are projected to continue. Climate change is projected to increase river flooding, particularly in northern Europe, as higher temperatures intensify the water cycle. However, it is difficult to discern the influence of climate change in flooding data records for the past. River flow droughts appear to have become more severe and frequent in southern Europe. Minimum river flows are projected to decrease significantly in summer in southern Europe but also in many other parts of Europe to varying degrees. The Arctic is warming faster than other regions. Record low sea ice was observed in the Arctic in 2007, 2011 and 2012, falling to roughly half the minimum extent seen

  12. Developing fish trophic interaction indicators of climate change for the Great Lakes

    Science.gov (United States)

    Kraus, Richard T.; Knight, Carey T.; Gorman, Ann Marie; Kocovsky, Patrick M.; Weidel, Brian C.; Rogers, Mark W.

    2016-01-01

    This project addressed regional climate change effects on aquatic food webs in the Great Lakes. We sought insights by examining Lake Erie as a representative system with a high level of anthropogenic impacts, strong nutrient gradients, seasonal hypoxia, and spatial overlap of cold- and cool-water fish guilds. In Lake Erie and in large embayments throughout the Great Lakes basin, this situation is a concern for fishery managers, as climate change may exacerbate hypoxia and reduce habitat volume for some species. We examined fish community composition, fine-scale distribution, prey availability, diets, and biochemical tracers for dominant fishes from study areas with medium-high nutrient levels (mesotrophic, Fairport study area), and low nutrient levels (oligotrophic, Erie study area). This multi-year database (2011-2013) provides the ability to contrast years with wide variation in rainfall, winter ice-cover, and thermal stratification. In addition, multiple indicators of dietary and distributional responses to environmental variability will allow resource managers to select the most informative approach for addressing specific climate change questions. Our results support the incorporation of some relatively simple and cost-efficient approaches into existing agency monitoring programs to track the near-term condition status of fish and fish community composition by functional groupings. Other metrics appear better suited for understanding longer-term changes, and may take more resources to implement on an ongoing basis. Although we hypothesized that dietary overlap and similarity in selected species would be sharply different during thermal stratification and hypoxic episodes, we found little evidence of this. Instead, to our surprise, this study found that fish tended to aggregate at the edges of hypoxia, highlighting potential spatial changes in catch efficiency of the fishery. This work has had several positive impacts on a wide range of resource management and

  13. The calculation of climatic indices for Late Quaternary faunal assemblages from South African sites

    Science.gov (United States)

    Thackeray, Francis

    2013-04-01

    The relative abundance of rodents and insectivores from several Late Quaternary sites in South Africa have been studied using multivariate analysis (notably factor analysis). The highest loadings on the first factor (F1) are obtained for taxa that are today found in warm subtropical environments, contrasting with taxa which have low F1 loadings and which are today distributed in more southerly latitudes and at high altitudes. The latter taxa with low loadings on F1 are able to tolerate cold conditions (and are relatively common in Terminal Pleistocene assemblages associated with Oxygen Isotope Stage 2). A summary statistic based on F1 (SSF1) is calculated and interpreted as a temperature index. The dated temperature indices for Boomplaas cave correlate well (r=0.95) with dated deuterium isotope ratios for a Vostok core in Antarctica. Similarly, a moisture index (SSF3) is calculated from factor analysis of the relative abundances of the same faunal assemblages. The results are assessed in terms of a non-linear pattern of variability in temperature and moisture indices calculated from pollen as well as mammalian microfauna. The changes in climate are likely to have influenced the distribution and abundance of human populations in the Late Pleistocene in southern Africa.

  14. Indicative effects of climate change on groundwater levels in Estonian raised bogs over 50 years

    Directory of Open Access Journals (Sweden)

    E. Lode

    2017-08-01

    Full Text Available Analyses of 50-year (1962–2011 monthly air temperature and precipitation data indicated substantial climate change in the locations of two raised bogs (Linnusaare and Männikjärve in central-east Estonia. During recent years the cross-year winter air temperature increased by 1.7 ºC, while the cold-season precipitation increased by 4 mm. The fluctuation amplitude of temperature and precipitation values decreased. Snow depth proved to be the most sensitive variable to winter warming, followed by groundwater levels together with mean and maximum soil frosts. Long-term groundwater levels on the domes of the bogs and in the forested/treed lagg areas were 0.3−0.4 m and 0.4−0.8 m below the soil surface, respectively. Warming caused changes in groundwater level amplitude of 3−22 cm in the bog domes and 3−14 cm in the forested lagg zones. The lowest groundwater levels in ridge-pool ecotopes at Männikjärve rose by 6−10 cm (i.e. these ecotopes became wetter; but the incidence of low groundwater levels increased in most ecotopes, indicating a more general trend towards drier conditions in the bog.

  15. Wavelet analysis of some rivers in SE Europe and selected climate indices.

    Science.gov (United States)

    Briciu, Andrei-Emil; Mihăilă, Dumitru

    2014-10-01

    The influence of some climatic oscillations and sunspot number on river flows in Romania, Ukraine, and Moldova is verified by using standard wavelet analyses. The selected climate oscillations are Arctic Oscillation (AO), Antarctic Oscillation (AAO), East Atlantic Oscillation (EAO), East Atlantic/West Russia Oscillation (EAWRO), NINO3.4, North Atlantic Oscillation (NAO), Pacific/North America Oscillation (PNAO), Pacific Decadal Oscillation (PDO), Polar/Eurasia Oscillation (PEO), Scandinavian Oscillation (ScandO), Southern Oscillation (SO), and West Pacific Oscillation (WPO). Forty-five hydrological stations from an area of 45,000 km(2) were used in order to discover the spatial evolution of the periodicities found in rivers. The wavelet analysis is novel for the rivers in the study area. There is an important difference between the periodicities found in mountain and plateau areas and those found in the plain area. There is a general downstream increase in the confidence level of the identified periods, even if the atmospheric precipitation has more relevant periodicities in the mountain area. The periodicities can be grouped into two compact groups: 1-16.5 and 27.8-55.6 years. The correlation matrix of the global wavelet spectrum (GWS) values indicates that NAO, EAWRO, PDO, and the sunspot number are the main factors that generate the periodicities in rivers. It is the first time when the influence of PDO on local rivers is proven. All river periodicities smaller than 16 years have a confidence level of 0.95 or above, as proven by the GWS analysis of the daily discharge data, and are caused by multiple external factors.

  16. [Munchausen by proxy syndrome].

    Science.gov (United States)

    Depauw, A; Loas, G; Delhaye, M

    2015-01-01

    The Munchausen syndrome by proxy (MSBP) was first described in 1977 by the English paediatrician Roy Meadow. The MSBP is an extremely complicated diagnosis because of the difficulty in finding the incriminating evidence of its existence and because of the ethical issue it raises for caregivers. Its implications from a medical, psychological and legal point of view raise difficult questions for any professional confronted to it. In this article we will first present the case of a 16-year-old teenager who had been bedridden in hospital for a year, before an atypical form of MSBP was finally diagnosed, after a stay in a child and adolescent psychiatry unit. We will then discuss this case in light of a literature review on the MSBP.

  17. Carbohydrates and phenols as quantitative molecular vegetation proxies in peats

    Science.gov (United States)

    Kaiser, K.; Benner, R. H.

    2012-12-01

    Vegetation in peatlands is intricately linked to local environmental conditions and climate. Here we use chemical analyses of carbohydrates and phenols to reconstruct paleovegetation in peat cores collected from 56.8°N (SIB04), 58.4°N (SIB06), 63.8°N (G137) and 66.5°N (E113) in the Western Siberian Lowland. Lignin phenols (vanillyl and syringyl phenols) were sensitive biomarkers for vascular plant contributions and provided additional information on the relative contributions of angiosperm and gymnosperm plants. Specific neutral sugar compositions allowed identification of sphagnum mosses, sedges (Cyperaceae) and lichens. Hydroxyphenols released by CuO oxidation were useful tracers of sphagnum moss contributions. The three independent molecular proxies were calibrated with a diverse group of peat-forming plants to yield quantitative estimates (%C) of vascular plant, sphagnum moss and lichen contributions in peat core samples. Correlation analysis indicated the three molecular proxies produced fairly similar results for paleovegetation compositions, generally within the error interval of each approach (≤26%). The lignin-based method generally lead to higher estimates of vascular plant vegetation. Several significant deviations were also observed due to different reactivities of carbohydrate and phenolic polymers during peat decomposition. Rapid vegetation changes on timescales of 50-200 years were observed in the southern cores SIB04 and SIB06 over the last 2000 years. Vanillyl and syringyl phenol ratios indicated these vegetation changes were largely due to varying inputs of angiosperm and gymnosperm plants. The northern permafrost cores G137 and E113 showed a more stable development. Lichens briefly replaced sphagnum mosses and vascular plants in both of these cores. Shifts in vegetation did not correlate well with Northern hemisphere climate variability over the last 2000 years. This suggested that direct climate forcing of peatland dynamics was overridden

  18. Effect of motivational climate profiles on motivational indices in team sport.

    Science.gov (United States)

    Ommundsen, Y; Roberts, G C

    1999-12-01

    Contemporary perspectives of achievement motivation have been based on social cognitive theories which give motivational climate a central place in the regulation of subsequent affective states, cognitions and behaviour in achievement contexts. This study examined the relationship between different profiles of the motivational climate in teamsport and achievement, and socially related cognitions among Norwegian team sport athletes. Players (N= 148) assessed their perception of the motivational climate using the Norwegian version of the Motivational climate in sport questionnaire, sources of satisfaction in team sport, achievement strategies, perceived purposes of sport, and conceptions of ability. Multivariate analysis of variance (2x2) showed both main effects for profiles of the motivational climate and an interaction effect. Athletes perceiving the climate as high in mastery and high in performance oriented criteria reported psychological responses that were more adaptative than those perceiving the climate as low in mastery and high in performance criteria. With one exception, the findings showed that those high in mastery and low in performance were more likely to emphasise self-referenced criteria when judging perceived ability in team sport. For both social responsibility and lifetime skills as purposes in sport, it was the high performance and low mastery athletes who were least likely to endorse these purposes. And importantly, the high mastery climate seemed to moderate the impact of being in a high performance climate. The pattern of findings suggests that perceiving the motivational climate as performance oriented may not be motivationally maladaptive when accompanied by mastery oriented situational cues.

  19. An approach to developing local climate change environmental public health indicators, vulnerability assessments, and projections of future impacts.

    Science.gov (United States)

    Houghton, Adele; English, Paul

    2014-01-01

    Environmental public health indicators (EPHIs) are used by local, state, and federal health agencies to track the status of environmental hazards; exposure to those hazards; health effects of exposure; and public health interventions designed to reduce or prevent the hazard, exposure, or resulting health effect. Climate and health EPHIs have been developed at the state, federal, and international levels. However, they are also needed at the local level to track variations in community vulnerability and to evaluate the effectiveness of interventions designed to enhance community resilience. This review draws on a guidance document developed by the U.S. Council of State and Territorial Epidemiologists' State Environmental Health Indicators Collaborative climate change working group to present a three-tiered approach to develop local climate change EPHIs. Local climate change EPHIs can assist local health departments (LHDs) in implementing key steps of the 10 essential public health services and the U.S. Centers for Disease Control and Prevention's Building Resilience Against Climate Effects framework. They also allow LHDs to incorporate climate-related trends into the larger health department planning process and can be used to perform vulnerability assessments which can be leveraged to ensure that interventions designed to address climate change do not exacerbate existing health disparities.

  20. Spatial patterns of trends and teleconnections in climate indices relevant for Mexican maize

    Science.gov (United States)

    Dewes, C. F.

    2013-05-01

    This study contributes to the discussion of climate trends in Mexico and the influence of hemispheric-scale variability patterns over the period 1950-2008. Its uniqueness is three-fold. First, the choice of climate indices under scrutiny aims to represent an agro-climatic perspective, geared towards maize in particular because of the major role this crop plays in Mexico's culture, diet, and economy. Second, the spatial resolution and coverage of these findings can be useful for interpretations at the local level (i.e. district or state), yet keeping the broad national picture in perspective. This should be particularly useful to agro-climate forecasting, assessment of impacts, and/or policy development. Third, this study uncovers a dominance of the North Atlantic over the Pacific Ocean in respect to remote influences on trend patterns in Mexico. Trends in precipitation show that east of the central highlands, the rainy season is starting later and becoming drier. The same is occurring along the Pacific coastal plain, but there an increase in extreme events is also observed. For south-central Mexico and the Yucatán, rains not only are starting earlier but intensity and frequency of extreme events are also increasing. In some of these areas dry days are becoming more frequent. Trends in temperature suggest that highlands are warming at faster rates than lowlands, which in some places are actually cooling. Warming in the fall-winter growing season is more pronounced than in the spring-summer growing season. On the other hand, cold spells during mid-summer are becoming more frequent over the highlands. Connections were found between these trends and large-scale variability patterns, namely El Niño Southern Oscillation (ENSO), Pacific North America (PNA), the North Atlantic Oscillation (NAO), and Caribbean sea surface temperatures (SSTs). Interannual variability related to ENSO and the PNA, and trends towards more Niño-like conditions, are associated with increasing

  1. Combined use of relative drought indices to analyze climate change impact on meteorological and hydrological droughts in a Mediterranean basin

    Science.gov (United States)

    Marcos-Garcia, P.; Lopez-Nicolas, A.; Pulido-Velazquez, M.

    2017-11-01

    Standardized drought indices have been traditionally used to identify and assess droughts because of their simplicity and flexibility to compare the departure from normal conditions across regions at different timescales. Nevertheless, the statistical foundation of these indices assumes stationarity for certain aspects of the climatic variables, which could no longer be valid under climate change. This contribution provides a framework to analyze the impact of climate change on meteorological and hydrological droughts, considering shifts in precipitation and temperature, adapted to a Mediterranean basin. For this purpose, droughts are characterized through a combination of relative standardized indices: Standardized Precipitation Index (rSPI), Standardized Precipitation Evapotranspiration Index (rSPEI) and a Standardized Flow Index (rSFI). The uncertainty and the stationarity of the distribution parameters used to compute the drought indices are assessed by bootstrapping resampling techniques and overlapping coefficients. For the application of the approach to a semiarid Mediterranean basin (Jucar River Basin), the Thornthwaite scheme was modified to improve the representation of the intra-annual variation of the potential evapotranspiration and low flow simulation in hydrological modelling was improved for a better characterization of hydrological droughts. Results for the Jucar basin show a general increase in the intensity and magnitude of both meteorological and hydrological droughts under climate change scenarios, due to the combined effects of rainfall reduction and evapotranspiration increase. Although the indicators show similar values for the historical period, under climate change scenarios the rSPI could underestimate the severity of meteorological droughts by ignoring the role of temperature.

  2. Analysis of climate change indices in relation to wine production: A case study in the Douro region (Portugal

    Directory of Open Access Journals (Sweden)

    Blanco-Ward Daniel

    2017-01-01

    Full Text Available Climate change is of major relevance to wine production as most of the wine-growing regions of the world, in particular the Douro region, are located within relatively narrow latitudinal bands with average growing season temperatures limited to 13–21°C. This study focuses on the incidence of climate variables and indices that are relevant both for climate change detection and for grape production with particular emphasis on extreme events (e.g. cold waves, storms, heat waves. Dynamical downscaling of MPI-ESM-LR global data forced with RCP8.5 climatic scenario is performed with the Weather Research and Forecast (WRF model to a regional scale including the Douro valley of Portugal for recent-past (1986–2005 and future periods (2046–2065; 2081–2100. The number, duration and intensity of events are superimposed over critical phenological phases of the vine (dormancy, bud burst, flowering, véraison, and maturity in order to assess their positive or negative implications on wine production in the region. An assessment on the statistical significance of climatic indices, their differences between the recent-past and the future scenarios and the potential impact on wine production is performed. Preliminary results indicate increased climatic stress on the Douro region wine production and increased vulnerability of its vine varieties. These results will provide evidence for future strategies aimed to preserve the high-quality wines in the region and their typicality in a sustainable way.

  3. A statistical proxy for sulphuric acid concentration

    Directory of Open Access Journals (Sweden)

    S. Mikkonen

    2011-11-01

    Full Text Available Gaseous sulphuric acid is a key precursor for new particle formation in the atmosphere. Previous experimental studies have confirmed a strong correlation between the number concentrations of freshly formed particles and the ambient concentrations of sulphuric acid. This study evaluates a body of experimental gas phase sulphuric acid concentrations, as measured by Chemical Ionization Mass Spectrometry (CIMS during six intensive measurement campaigns and one long-term observational period. The campaign datasets were measured in Hyytiälä, Finland, in 2003 and 2007, in San Pietro Capofiume, Italy, in 2009, in Melpitz, Germany, in 2008, in Atlanta, Georgia, USA, in 2002, and in Niwot Ridge, Colorado, USA, in 2007. The long term data were obtained in Hohenpeissenberg, Germany, during 1998 to 2000. The measured time series were used to construct proximity measures ("proxies" for sulphuric acid concentration by using statistical analysis methods. The objective of this study is to find a proxy for sulfuric acid that is valid in as many different atmospheric environments as possible. Our most accurate and universal formulation of the sulphuric acid concentration proxy uses global solar radiation, SO2 concentration, condensation sink and relative humidity as predictor variables, yielding a correlation measure (R of 0.87 between observed concentration and the proxy predictions. Interestingly, the role of the condensation sink in the proxy was only minor, since similarly accurate proxies could be constructed with global solar radiation and SO2 concentration alone. This could be attributed to SO2 being an indicator for anthropogenic pollution, including particulate and gaseous emissions which represent sinks for the OH radical that, in turn, is needed for the formation of sulphuric acid.

  4. Climate Reconstructions

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Paleoclimatology Program archives reconstructions of past climatic conditions derived from paleoclimate proxies, in addition to the Program's large holdings...

  5. Reconstruction of Past Climatic Proxy Series

    Science.gov (United States)

    1975-08-29

    zones, herb pollen, such as Artemisia and Chenopodeaceae are dominant (6e). Deciduous arboreal pollen is restricted to the mixed forest zone (6f... reproduction and an increase in the longer lived species such as hemlock (Tsuga canadensis) and spruce (Picea, sp.) which can reproduce in the absence of fire...are only temporary during the 1450-1850 A.D. interval since it is later replaced by hemlock. White pine also requires fire for good reproduction

  6. Constraining the Paleogene of South America: Magnetostratigraphy and paleoclimate proxy records from Cerro Bayo (Provincia de Salta, Argentina)

    Science.gov (United States)

    Hyland, E.; Cotton, J. M.; Sheldon, N. D.

    2012-12-01

    Records of rapid climatic and ecological shifts in the past are crucial for understanding global systems and for predicting future impacts of climate change. Transient and broad scale hyperthermal events during the Paleogene, such as the Paleocene-Eocene Thermal Maximum (PETM) and Early Eocene Climatic Optimum (EECO), have been studied extensively through both marine records and a significant terrestrial record from North America. Despite this, little evidence exists from the climatic and ecological histories of other major landmasses, which limits the effectiveness of global climate response predictions. Here we present an integrated paleoenvironmental reconstruction of the early Paleogene from a site in central South America (Cerro Bayo, Argentina), including a new magnetostratigraphic age model, pedological and sedimentological interpretation, whole rock geochemical climate proxies, isotopic environmental proxies, and microfloral assemblages. Cerro Bayo is a 235-meter terrestrial section that exposes the Tunal, Mealla, and Maiz Gordo Formations, and based on magnetostratigraphic interpolation spans roughly 58—50 Mya, including both the PETM and EECO events. These formations are composed primarily of reddish sandstone and siltstone, much of which exhibits features characteristic of a moderate degree of pedogenesis (i.e., Inceptisols and Alfisols). High-resolution climate proxies derived from paleosol geochemical compositions highlight rapid increases in mean annual temperature (>5°C) and precipitation (>300 mm yr-1) during the PETM, as well as more gradual increasing temperature and precipitation trends leading up to the EECO. Carbon isotope stratigraphy through the section also indicates a sizable negative excursion (~4‰) during the PETM, and generally positive isotopic trends during the early Eocene. Phytolith biostratigraphy also details changes in local vegetation composition during climatic events that corresponds to similar patterns seen in terrestrial

  7. Private Computing with Untrustworthy Proxies

    NARCIS (Netherlands)

    Gedrojc, B.

    2011-01-01

    The objective of this thesis is to preserve privacy for the user while untrustworthy proxies are involved in the communication and computation i.e. private computing. A basic example of private computing is an access control system (proxy) which grants access (or not) to users based on fingerprints.

  8. How Does the Variability in the Frequency and Intensity of Extreme Climate Indices Explain Variability in Crop Productivity for Turkey?

    Science.gov (United States)

    An, Nazan; Kurnaz, M. Levent

    2017-04-01

    Studies in the literature usually focus on the effects of climate change on crop productivity and yield, but the studies on how long-term climate variability has an impact on crop productivity and yield draw attention less. In addition, these studies are mostly carried out using statistical methods and predictions with basic climate parameters. To this respect, we have used indices indicating effects of extreme climatic events on wheat and maize productivity instead of basic climate parameters through a crop model called as CROPSYST for the domain of Turkey for the period of 2020-2050 with respect to the reference period of 1991-2012. Based on this, we tried to see how wheat and maize, which grow in most part of Turkey, would be affected within the scope of climate change in the near future period. Model results show that crop productivity will be affected in some part of the domain in the near-future period. Acknowledgement: This research has been supported by Bogazici University Research Fund Grant Number 12220.

  9. Annual Cambial Rhythm in Pinus halepensis and Pinus sylvestris as Indicator for Climate Adaptation.

    Science.gov (United States)

    Prislan, Peter; Gričar, Jožica; de Luis, Martin; Novak, Klemen; Martinez Del Castillo, Edurne; Schmitt, Uwe; Koch, Gerald; Štrus, Jasna; Mrak, Polona; Žnidarič, Magda T; Čufar, Katarina

    2016-01-01

    To understand better the adaptation strategies of intra-annual radial growth in Pinus halepensis and Pinus sylvestris to local environmental conditions, we examined the seasonal rhythm of cambial activity and cell differentiation at tissue and cellular levels. Two contrasting sites differing in temperature and amount of precipitation were selected for each species, one typical for their growth and the other represented border climatic conditions, where the two species coexisted. Mature P. halepensis trees from Mediterranean (Spain) and sub-Mediterranean (Slovenia) sites, and P. sylvestris from sub-Mediterranean (Slovenia) and temperate (Slovenia) sites were selected. Repeated sampling was performed throughout the year and samples were prepared for examination with light and transmission electron microscopes. We hypothesized that cambial rhythm in trees growing at the sub-Mediterranean site where the two species co-exist will be similar as at typical sites for their growth. Cambium in P. halepensis at the Mediterranean site was active throughout the year and was never truly dormant, whereas at the sub-Mediterranean site it appeared to be dormant during the winter months. In contrast, cambium in P. sylvestris was clearly dormant at both sub-Mediterranean and temperate sites, although the dormant period seemed to be significantly longer at the temperate site. Thus, the hypothesis was only partly confirmed. Different cambial and cell differentiation rhythms of the two species at the site where both species co-exist and typical sites for their growth indicate their high but different adaptation strategies in terms of adjustment of radial growth to environmental heterogeneity, crucial for long-term tree performance and survival.

  10. Remote Detection of Climate Change Indicators in the Mission Mountain Range: Tracking Ice Field Movement

    Science.gov (United States)

    Sifford, C. N.; Kenning, R.; Carlson, M.; Rock, B. N.

    2010-12-01

    This study compared Landsat images over a 22-year span from 1987-2009 to map the change in size of the McDonald snow and ice fields in the Mission Mountains on the Flathead Reservation. Our hypothesis was that a variation in snow and ice field size can be used as an indicator of climate change on a local level. This hypothesis proved true. Analyzing snow and ice field acreage from 8 Landsat images representing September dates from different years (1987, 1990, 1991, 1994, 2005, 2007, 2008, and 2009) created with MultiSpec and ArcMap, we then created a sum of acres for each year that yielded a slight downward trend in area of snow and ice fields. The study found an upward trend in the average temperature for the month of September over a 100-year span (1909- 2009) of approximately 2.0o F, from 55o F to more than 57o F. Calculations of snow and ice field area were made from a Normalized Difference Snow and Ice Index (NDSII) of the September months’ ice/snow cover, using Multispec, and attribute table measures of those areas in ArcMap. Years 1990 and 1991 showed 738 and 700 acres, respectively; in the current decade the largest acreage was in 2005 with 531 acres and the lowest was in 2007 at 232 acres. I conclude that using remote sensing methods prove a reliable source for analyzing land cover such as snow and ice. Cloud cover remains a constant issue in acquiring usable data due to interference from clouds. Graphing the analyzed data from the 8 Landsat scenes shows a slight downward trend (Formula y = -4.6802x + 515.84 R2 = 0.0494).

  11. Source-specific diatom lipid biomarkers as proxies for Arctic and Antarctic sea ice

    Science.gov (United States)

    Belt, Simon

    2016-04-01

    Sea ice plays a key role in controlling global climate due its influence over heat and gas exchange between the oceans and the atmosphere. In addition, sea ice exerts a strong influence over the absorption of incoming radiation at the ocean surface as a result of its high reflectivity or albedo. Driven, in part, by the recent dramatic changes to sea ice cover in both the Arctic and the Antarctic, the development of proxies for sea ice has received growing attention over the last 10 years or so. Amongst these, some so-called highly branched isoprenoid (HBI) lipid biomarkers have attracted considerable interest, not least, because they are derived from certain diatoms that reside and bloom within the sea ice matrix itself, thus providing a more direct indication of sea ice presence compared with some other proxies. The signature HBI sea proxies are a mono-unsaturated HBI (IP25) for the Arctic and a di-unsaturated HBI (C25:2) for the Antarctic, with different source organisms for each. Although the variability in sedimentary abundances of IP25 and C25:2 in Arctic and Antarctic sediments generally reflect the corresponding changes in sea ice conditions, a more complete picture of reconstructing sea ice conditions likely requires a multi-proxy approach involving, for example, other lipid biomarkers that serve as proxy measures of nearby open water conditions or sea surface temperature. By adoption of such an approach, a research strategy aimed at improving estimates of sea ice concentrations or better definitions of sea ice conditions (e.g. marginal ice zone, polynyas, permanent ice cover) represents the next stage in lipid-based sea ice proxy development. This presentation will focus on recent developments and future plans that involve a multi-proxy approach to improving sea ice reconstruction. An understanding of sources, ecology and environmental fate of various HBIs and other diatom lipids will likely be key in shaping the future direction of lipid-based sea ice

  12. Synchronous fire activity in the tropical high Andes: an indication of regional climate forcing

    NARCIS (Netherlands)

    Roman-Cuesta, R.M.; Carmona-Moreno, C.; Lizcano, G.; New, M.; Silman, M.R.; Knoke, T.; Malhi, Y.; Oliveras Menor, I.; Asbjornsen, H.; Vuille, M.

    2014-01-01

    Global climate models suggest enhanced warming of the tropical mid and upper troposphere, with larger temperature rise rates at higher elevations. Changes in fire activity are amongst the most significant ecological consequences of rising temperatures and changing hydrological properties in

  13. Do Himalayan treelines respond to recent climate change? An evaluation of sensitivity indicators

    OpenAIRE

    U. Schickhoff; Bobrowski, M; Böhner, J.; B. Bürzle; Chaudhary, R. P.; L. Gerlitz; H. Heyken; Lange, J.; Müller, M.; Scholten, T.; Schwab, N; R. Wedegärtner

    2015-01-01

    Climate warming is expected to induce treelines to advance to higher elevations. Empirical studies in diverse mountain ranges, however, give evidence of both advancing alpine treelines and rather insignificant responses. The inconsistency of findings suggests distinct differences in the sensitivity of global treelines to recent climate change. It is still unclear where Himalayan treeline ecotones are located along the response gradient from rapid dynamics to apparently compl...

  14. Do Himalayan treelines respond to recent climate change? An evaluation of sensitivity indicators

    OpenAIRE

    U. Schickhoff; Bobrowski, M; Böhner, J.; B. Bürzle; Chaudhary, R. P.; L. Gerlitz; H. Heyken; Lange, J.; Müller, M.; Scholten, T.; Schwab, N; R. Wedegärtner

    2014-01-01

    Climate warming is expected to induce treelines to advance to higher elevations. Empirical studies in diverse mountain ranges, however, give evidence of both advancing alpine treelines as well as rather insignificant responses. The inconsistency of findings suggests distinct differences in the sensitivity of global treelines to recent climate change. It is still unclear where Himalayan treeline ecotones are located along the response gradient from rapid dynamics ...

  15. EnviroAtlas: A Spatially Explicit Tool Combining Climate Change Scenarios with Ecosystem Services Indicators

    Science.gov (United States)

    Neale, A. C.; Pickard, B. R.; Megan, M.; Baynes, J.

    2014-12-01

    While discussions of global climate change tend to center on greenhouse gases and sea levelrise, other factors, such as technological developments, land and energy use, economics, and populationgrowth all play a critical role in understanding climate change. There is increasing urgency for methodsto forecast how different sectors, in particular ecosystems and the goods and services they provide, maybe altered as a result of climate change. However, due to their complexity, it is difficult to assess theseecosystem services at a single point in space or time, as they may be influenced by surrounding anddistant patterns of land use and biophysical attributes in addition to climate change. In order to makemeaningful conservation and adaptation choices, specific ecosystem components must be viewed inrelation to future climate information. The US Environmental Protection Agency and its partners, havedeveloped EnviroAtlas, a web-based geospatial tool that allows users to interact with climate changemodeling information while simultaneously providing a range of information and data on differentecosystem goods and services. This can be a useful platform for inquiry about the supply, demand, orbenefits provided by a specific ecosystem service, and to understand the potential impacts to thatecosystem service due to our changing climate. Housing a variety of data in one publicly available toolencourages users to think in new, trans-disciplinary ways that focus on the relationships betweenecosystem services and climate change impacts. By combining many fields of research through this easyto-use interface, the result is a novel tool that is spatially and temporally explicit and enables betterdecision making across multiple sectors. This talk will illustrate how the information presented inEnviroAtlas can be used in research.

  16. Geomorphic Indicators of Ground Ice on Mars and Evidence for Climate Change

    Science.gov (United States)

    Mustard, J. F.

    2003-12-01

    Until recently, indications of the presence of ice in the near surface of Mars, outside the polar caps, has depended upon the interpretation of morphology from imaging data. Early work in this area was based primarily on Viking orbiter images where several large landforms (100s to 1000s of meters in scale) were interpreted to be related to the presence of ice in the regolith or upper crust. These include lineated valley fill, concentric crater fill, softened terrain, and polygons, and are typically found between the latitudes of 30° -60° N and S. Without direct measurements of the presence of water, the interpretations rely on analogies with Earth's periglacial and glacial morphologies as well as geophysical modeling of ice-rich soils and crustal material. New spacecraft data from the Mars Global Surveyor and Mars Odyssey missions have significantly added to the family of morphologies with ground-ice affinities. From the high spatial resolution images acquired by Mars Orbiter Camera (MOC) a new array of polygons have been detected which range in size from 25-200 m and show strong latitudinal gradients above 50° . A possibly related morphology exhibiting a regularly spaced surface texture resembling the texture of a basketball is also found in these high latitudes. A number of morphologies indicating viscous flow on steep slopes are found in the mid-latitudes and are consistent with an ice-rich soils deforming under martian surface conditions. A continuous deposit, meters-thick and interpreted to be ice rich is observed at latitudes above 60° , but that is in a degraded condition at lower latitudes (formerly ice-rich) and absent in the equatorial regions (within 30° ). The neutron spectrometer on the Odyssey spacecraft made direct measurements of hydrogen which shows clearly the presence of high water-ice abundance (>70% by volume) in the surface soils in the northern and southern latitudes above 60° . This critical observation ties in well with theoretical

  17. A COMPARATIVE ASSESSMENT OF SEQUENCES OF DROUGHT WEATHER INDICES, BY TIME SCALES AND CLIMATE IN SENEGAL AREAS

    Directory of Open Access Journals (Sweden)

    Cheikh FAYE

    2017-04-01

    Full Text Available The management water resource in our States is harder and harder lately because of the frequency and of the intensity of droughts. Senegal, as most tropical States, knew an alternation of wet and dry periods. In this climatic context more and more disrupted by the anthropological activities, it is essential to analyze the dry episodes on various climatic domains, in diverse temporal scales and by diverse indications to propose to the populations of the measures of mitigation or adaptation regarding management of water. In this article, pluviometric data of six stations located in three climatic domains were analyzed. The analysis used and compared the values of the rainfall deviations decimal logarithm index (RDI, the rainfall anomalies index (RAI and the standardized precipitation index (SPI calculated for timescales of 5 years, of 25 years and of 50 years. The results indicate that the most remarkable droughts due to their intensity, their duration and their frequency occurred during decades 1970 and 1980 whatever the index, the timescale and the used climatic domain. These dry episodes reached their paroxysm in 1972 and 1983 with droughts of an extreme severity. The climatic domains are affected well by drought, but to varying degrees. Besides, it appears that the ISP index and the long-term timescale seems the best suited to describe with more precision the dry episodes in Senegal, and most affected continental Sahelian domain.

  18. Observable Proxies For 26 Al Enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Fryer, Christopher L [Los Alamos National Laboratory; Young, Patrick A [Los Alamos National Laboratory; Ellinger, Carola I [ASU; Arnett, William D [UNIV ARIZONA

    2008-01-01

    We consider the cospatial production of elements in supernova explosions to find observationally detectable proxies for enhancement of {sup 26}Al in supernova ejecta and stellar systems. Using four progenitors we explore a range of 1D explosions at different energies and an asymmetric 3D explosion. We find that the most reliable indicator of the presence of {sup 26}Al in unmixed ejecta is a very low S/Si ratio ({approx} 0.05). Production of N in O/S/Si-rich regions is also indicative. The biologically important element P is produced at its highest abundance in the same regions. Proxies should be detectable in supernova ejecta with high spatial resolution multi wavelength observations, but the small absolute abundance of material injected into a proto-planetary disk makes detection unlikely in existing or forming stellar/planetary systems.

  19. Comparison and statistical analysis of long-term overheating indices applied on energy renovated dwellings in temperate climates

    DEFF Research Database (Denmark)

    Psomas, Theofanis Ch.; Heiselberg, Per Kvols; Duer, Karsten

    2017-01-01

    of a dynamic energy performance engine and widely accepted calculation methods and statistical tools. The statistical analyses show that dynamic indices originate from the same adaptive comfort theory directly related with each other. In addition, it is possible to create general and widely applied....... Correlation of indices would simplify the analysis being conducted during the design (optimization process) or operational (comfort assessment) phase of buildings. This research compares and statistically correlates results of seven widely used long-term overheating indices on four ‘free...... relationships between static overheating indices independently of the case study and climatic condition....

  20. Statistical Analysis of Extreme Climatic Indices to Determine Environmental Change in Former and Present Karner Blue Butterfly Habitats

    Science.gov (United States)

    Liu, H.; Gomezdelcampo, E.

    2008-12-01

    The Karner Blue butterfly is a federally endangered species that once was widely distributed throughout 12 states along the northern part of the United States and Ontario, Canada. Now it only exists in seven states. Many factors are considered to have affected the extinction of this species and this study examines the effect of climate change on the persistence of the Karner Blue butterfly. Five sites were selected to study the effect of climate change. Three sites currently have a Karner Blue population (Allegan, MI, Fort McCoy, WI, and Saratoga, NY) and two sites the Karner Blue has disappeared (Oak Openings, OH, and Pinery, Ontario). Daily climate data from the 1950s to 2005 were used for calculating 13 extreme climatic indices related to precipitation and temperature. The data were broken into two time periods (pre-1984 and post-1984) to analyze how those indices have changed since the butterfly disappeared from the two sites. Statistical analyses including t-tests and ANOVA were used to compare these indices within two time periods among five sites. The results showed that different indices have changed differently among the five sites. The number of extreme hot days and number of extreme cold days per year have a statistically significant change in the sites where the Karner Blue butterfly disappeared. The precipitation-related indices do not show a statistically significant different trend among the five sites. Temperature seems to have more of an effect on the existence of the Karner Blue butterfly. Furthermore, butterfly population size and lake effects are also important factors that cannot be neglected. Larger populations seem to have better chances to survive during a dramatic climate change event.

  1. Volcano and Ship Tracks Indicate Excessive Aerosol-Induced Cloud Water Increases in a Climate Model

    Science.gov (United States)

    Toll, Velle; Christensen, Matthew; Gassó, Santiago; Bellouin, Nicolas

    2017-12-01

    Aerosol-cloud interaction is the most uncertain mechanism of anthropogenic radiative forcing of Earth's climate, and aerosol-induced cloud water changes are particularly poorly constrained in climate models. By combining satellite retrievals of volcano and ship tracks in stratocumulus clouds, we compile a unique observational data set and confirm that liquid water path (LWP) responses to aerosols are bidirectional, and on average the increases in LWP are closely compensated by the decreases. Moreover, the meteorological parameters controlling the LWP responses are strikingly similar between the volcano and ship tracks. In stark contrast to observations, there are substantial unidirectional increases in LWP in the Hadley Centre climate model, because the model accounts only for the decreased precipitation efficiency and not for the enhanced entrainment drying. If the LWP increases in the model were compensated by the decreases as the observations suggest, its indirect aerosol radiative forcing in stratocumulus regions would decrease by 45%.

  2. When will climate scenario runs show a statistically significant change in drought indices?

    Science.gov (United States)

    Thejll, P.; Fox Maule, C.; Hesselbjerg Christensen, J.

    2012-04-01

    Climate models can be used to evaluate the consequences of various emission scenarios. A common application is to look at scenario runs and find out what will happen to e.g. temperature or precipitation in the future. Typically, the result is that some model observable will increase or decrease in the mean as time passes in the model. Given the model level of variability it is possible to ask when a particular quantity rises (or falls) so much that the change, relative to some base period, can be said to be statistically significant. We investigate when the mean of two drought indices - the Standardized Precipitation Index (SPI) and the self-calibrated Palmer Drought Severity Index (scPDSI) - change by a statistically significant amount over regions of Europe in the A1B scenario runs from the ENSEMBLES project. Assessment of the statistical significance hinges on a thorough understanding of the number of degrees of freedom - N - in the model fields - in time and space. We use a simple approach and set upper and lower limits on N, and calculate the probabilities corresponding to model field mean changes. The results are that a statistically significant change in the mean scPDSI index occurs in some of the European regions in the models - with good uniformity across the range of models. For the SPI a similar result is found, but less distinctly, with the most similar results in the NW and SW tending to occur a little later than for the scPDSI. Typically the clearest change-signals are seen in the North-West and South-West of Europe. The scPDSI depends on temperature as well as precipitation so the clarity of the signal in the scPDSI may be due to the more robustly modelled future temperature changes. A similar analysis of the changes of drought-index variance has not yielded any clear results. We use these findings to discuss the extent to which scenario runs may be used in predictions of real-world drought-condition changes across Europe.

  3. Robotic Vehicle Proxy Simulation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Energid Technologies proposes the development of a digital simulation that can replace robotic vehicles in field studies. This proxy simulation will model the...

  4. ICUD-0420 Testing high resolution synthetic rainfall time series representing current and future climates on CSO and other indicators

    DEFF Research Database (Denmark)

    Sørup, Hjalte Jomo Danielsen; Davidsen, S.; Löwe, Roland

    2017-01-01

    Combined sewer systems have a long technical lifetime, thus climate change must be taken into consideration when designing new CSO structures, basins, and pipe system enhancements. At the same time, the performance is highly dependent on antecedent conditions in the sewer system and is therefore...... best modelled using LTS. In the present study, we calculate indicators related to CSO statistics using synthetic time series created with different methodologies for both present and future climatic conditions. The methodology for synthetic rainfall generation influences the obtained results along...

  5. Assessing the Role of Energy in Development and Climate Policies - Conceptual Approach and Key Indicators

    DEFF Research Database (Denmark)

    Halsnæs, Kirsten; Garg, Amit

    2011-01-01

    The paper discusses a number of key conceptual issues related to the role of energy in development and its potential synergies and tradeoffs with climate change. The relationship between economic development and energy over time is discussed and illustrated by data from China, India and South...... Africa, and some other countries. It concludes that energy plays an important role as a productivity enhancing factor in economic development and in human well being. Several policy goals related to sustainable development, energy, and climate can be integrated. However, meeting all these policy goals...

  6. Calcium isotopic composition of high-latitude proxy carrier Neogloboquadrina pachyderma (sin.

    Directory of Open Access Journals (Sweden)

    A. Eisenhauer

    2009-01-01

    Full Text Available The accurate reconstruction of sea surface temperature (SST history in climate-sensitive regions (e.g. tropical and polar oceans became a challenging task in palaeoceanographic research. Biogenic shell carbonate SST proxies successfully developed for tropical regions often fail in cool water environments. Their major regional shortcomings and the cryptic diversity now found within the major high latitude proxy carrier Neogloboquadrina pachyderma (sin. highlight an urgent need to explore complementary SST proxies for these cool-water regions. Here we incorporate the genetic component into a calibration study of a new SST proxy for the high latitudes. We found that the calcium isotopic composition (δ44/40Ca of calcite from genotyped net catches and core-top samples of the planktonic foraminifera Neogloboquadrina pachyderma (sin. is related to temperature and unaffected by genetic variations. The temperature sensitivity has been found to be 0.17 (±0.02‰ per 1°C, highlighting its potential for downcore applications in open marine cool-water environments. Our results further indicate that in extreme polar environments, below a critical threshold temperature of 2.0 (±0.5°C associated with salinities below 33.0 (±0.5‰, a prominent shift in biomineralization affects the δ44/40Ca of genotyped and core-top N. pachyderma (sin., becoming insensitive to temperature. These findings highlight the need of more systematic calibration studies on single planktonic foraminiferal species in order to unravel species-specific factors influencing the temperature sensitivity of Ca isotope fractionation and to validate the proxies' applicability.

  7. Iron content of soils as a precipitation proxy

    Science.gov (United States)

    Dzombak, R.; Sheldon, N. D.

    2016-12-01

    Given that different iron phases form under different precipitation and drainage regimes, soil iron content could be used as a proxy for both volume and seasonality of precipitation. Constraining these factors is important for predicting future precipitation trends, especially for a warmer climate that will likely see more frequent extreme weather events. Specifically, using paleoprecipitation data from periods of higher temperatures and atmospheric CO2 concentrations helps inform models of future `greenhouse' climate. Forty-five modern samples from across the continental United States were analyzed, with MAP ranging from 200 to 1200 mm yr-1 and MAT ranging from 5 to 22°C. Soil types included Alfisols (N=15), Inceptisols (N=8), Mollisols (N=15), and Aridisols (N=7), and ranged from seasonally wet to well-drained. Analytical techniques included combustion-elemental analysis and organic carbon isotope analysis, a sequential iron extraction modified with a sodium hypochlorite step for the extraction of organic matter-bound iron, and the extraction of iron sulfides. The sequential extractions yield five different `pools' of iron found in sediment: crystalline iron oxides (e.g., goethite, hematite), magnetite, carbonate-bound, organic matter-bound, and labile/easily reducible iron minerals (e.g., ferrihydrite). Analysis by ICP-OES yielded a strong relationship between magnetite-bound iron and MAP, and fair relationships between the other iron pools and MAP. Individual soil orders tended to show stronger relationships to the iron pools than all soils analyzed together, potentially indicating the need for separate proxy relationships for each soil order. Pyrite concentrations were well below 1% by weight for these soils, suggesting that none of these soils has a long enough wet season to encourage its formation and that the presence vs. absence of pyrite in paleosols may be a useful proxy for soil moisture state. In contrast to some earlier work, no significant

  8. Recent bottom sediments from Chukchi Sea, sampled northeast of Wrangel Island, indicate warmer climate (preliminary results)

    Science.gov (United States)

    Vologina, Elena G.; Sturm, Michael; Kolesnik, Alexandr N.; Bosin, Alexandr A.

    2014-05-01

    A short sediment core (37 cm long) was collected in Chukchi Sea at water depth 100 m northeast of Wrangel Island within the framework of the Russian-American project RUSALCA. Coordinates of coring site: 72º32.54'N 175º58.70'W. The sediments consist of silty clay and clayey silt with small admixtures of sand. They contain diatoms and spiculae of sponges. The deposits are olive-gray to greenish-gray and show black spots and stripes of hydrotroilite. Magnetic susceptibility varies from 28-42•10-6 SI units, with minimum values (28-32•10-6 SI units) observed in the uppermost 0-2 cm of the core. The generally constant magnetic susceptibility and the homogeneous lithology indicate calm conditions during sedimentation. Recent sedimentation rates, measured by 210Pb, average 0.7 mm/year. Thus the age of the studied sediment column is up to 530 years old, which corresponds to the Late Holocene [1]. Contents of biogenic silica (Sibio), mainly from diatoms, change from 11.14-16.00 %. Maximum values are observed in the uppermost part of the core at 0-1 cm (14.44 %) and down-core at 35 cm (16.00 %). Minimum contents correspond to core depths of 4-7 cm, 32 cm and 36 cm. Concentration of organic carbon (Corg) and total nitrogen (Ntot) are generally well correlated with biogenic silica. Maximum contents are observed in the interval 0-1 cm (2.19 % Corg and 0.28 % Ntot), minimum concentrations at intervals 5-6 cm (1.63-1.67 % Corg, 0.20-0.21 % Ntot.) and 31-33 cm (1.35-1.60 % Corg, 0.17-0.20 % Ntot). Concentrations of Corg and Ntot are mainly constant between 7 and 30 cm. In general, contents of Ntot are very small in the sediments. C/N ratios vary between 9-10, indicating a predominance of autochthonous organic matter in the deposits. The interval 0-1 cm corresponds to about the last 14 years. The high nutrient concentrations within this interval are caused probably by the increase of biological productivity in the Chukchi Sea increased during this time. This could be caused by

  9. Weather indicators for insured hailstorm damage to motor vehicles and potential climate change impacts

    NARCIS (Netherlands)

    Botzen, W.J.W.; Bouwer, L.M.

    2016-01-01

    Projections of the potential effects of climate change on damage caused by local extreme weather events are important for the design of appropriate policies for greenhouse gas emission reduction and insurers' adaptation responses to changing risks. This study estimates the relationships between

  10. Daily and monthly temperature and precipitation statistics as performance indicators for regional climate models

    DEFF Research Database (Denmark)

    Kjellström, Erik; Boberg, Fredrik; Castro, Manuel

    2010-01-01

    We evaluated daily and monthly statistics of maximum and minimum temperatures and precipitation in an ensemble of 16 regional climate models (RCMs) forced by boundary conditions from reanalysis data for 1961-1990. A high-resolution gridded observational data set for land areas in Europe was used....

  11. Spatiotemporal monthly rainfall forecasting for south-eastern and eastern Australia using climatic indices

    Science.gov (United States)

    Montazerolghaem, Maryam; Vervoort, Willem; Minasny, Budiman; McBratney, Alex

    2014-05-01

    Knowledge about future rainfall would significantly benefit land, water resources and agriculture management, as this assists with planning and management decisions. Forecasting spatiotemporal monthly rainfall is difficult, especially in Australia where there is a complex interaction between topography and the effect of Indian and Pacific Ocean. This study describes a method for spatiotemporal monthly rainfall forecasting in south-eastern and eastern part of Australia using climatic and non-climatic variables. Rainfall data were obtained from Bureau of Meteorology (BoM) from 136 high quality weather stations from the south-eastern and eastern part of Australia with monthly rainfall records from 1879 to 2012. To reduce spatial complexity of the area and improve model accuracy, spatial classification (regionalization) was considered as first step. Significant predictors for each sub-region among lagged climatic input variables were selected using Fuzzy Ranking Algorithm (FRA). Climate classification: 1) discovered homogenous sub-regions with a similar rainfall patterns and investigated spatiotemporal rainfall variations in the area, 2) allowed selection of significant predictors with a fine resolution for each area, 3) improved the prediction model and increased model accuracy. PCA was used to reduce the dimensions of the dataset and to remove the rainfall time series correlation. K-means clustering was used on the loadings of PCs describing 93% of long-term monthly rainfall variations. The analysis was repeated for different numbers of sub-regions (3 - 8) to identify the best number of clusters to improve the forecast model performance. Subsequently, a Fuzzy Ranking Algorithm (FRA) was applied to the lagged climatic predictors and monthly rainfall in each sub-region to identify the best predictors. After these two stages of pre-processing, a Neural Network model was developed and optimized for each of the sub-regions as well as for the entire area. It is concluded

  12. Future weather types and their influence on mean and extreme climate indices for precipitation and temperature in Central Europe

    Directory of Open Access Journals (Sweden)

    Ulf Riediger

    2014-09-01

    Full Text Available In Central Europe, the spatial and temporal distributions of precipitation and temperature are determined by the occurrence of major weather types. In this paper, we examine climate indices (i.e. mean values or hot, cold, wet and dry days for different weather types in a recent (1971–2000 and future climate (2070–2099. The weather types are classified objectively for the control run and for the A1B scenario with an ensemble of eight global climate simulations (GCM to be compared with different reanalyses. To derive climate indices, the high-resolution, regionalized reference dataset HYRAS and an ensemble of nine regional climate simulations (RCM are used. Firstly, the reliability of simulated weather patterns and their climate indices are tested in the control period. The reanalyses circulation climatology can be reproduced well by the GCM ensemble mean. For temperature and precipitation, each climate index is characterized and evaluated in terms of defined weather patterns. The comparison of HYRAS and RCM data show reliable mean temperature values with differences between weather classes by +2$+2$ to -6$-6$ °C during winter (13 to 19 °C in summer. The analysis of observed and simulated precipitation reveal that mean winter precipitation is significantly influenced by the direction of air flow, while in summer, mesoscale atmospheric patterns of cyclonic rotation play a larger role. Secondly, the analysis of potential future changes simulated by the RCM ensemble were able to demonstrate that weather type changes, superior climate trends (such as mean warming and their interaction lead to major changes for precipitation and temperature in Central Europe. While temperature differences between cold and warm weather types are nearly stable over time, the ensemble temperature changes (with a range of +2$+2$ to +4$+4$ °C reinforce warm/hot conditions in the future winter and summer. Milder, wetter winters can be explained by an increased

  13. Simple Indices Provide Insight to Climate Attributes Delineating the Geographic Range of Aedes albopictus (Diptera: Culicidae) Prior to Worldwide Invasion.

    Science.gov (United States)

    Mogi, Motoyoshi; Armbruster, Peter; Tuno, Nobuko; Campos, Raúl; Eritja, Roger

    2015-07-01

    Aedes albopictus (Skuse) has expanded its distribution worldwide during the past decades. Despite attempts to explain and predict its geographic occurrence, analyses of the distribution of Ae. albopictus in the context of broad climatic regions (biomes) has not been performed. We analyzed climate conditions at its distribution sites in the range before the worldwide invasions (from the easternmost Hawaii through westernmost Madagascar) by using thermal and aridity-humidity indices descriptive of major biomes. A significant advantage of this approach is that it uses simple indices clearly related to the population dynamics of Ae. albopictus. Although Ae. albopictus has been regarded as a forest species preferring humid climate, in areas with significant human habitation, the distribution sites extended from the perhumid, rain forest zone to the semiarid, steppe zone. This pattern was common from the tropics through the temperate zone. Across the distribution range, there was no seasonal discordance between temperature and precipitation; at sites where winter prevents Ae. albopictus reproduction (monthly meanswarm months (>10°C) under the Asian summer monsoon. Absence of the species in northern and eastern coastal Australia and eastern coastal Africa was not attributable solely to climate conditions. However, Asia west of the summer monsoon range was climatically unsuitable because of low precipitation throughout the year or in warm months favorable to reproduction (concentration of precipitation in winter). We hypothesized that Ae. albopictus originated in continental Asia under the monsoon climate with distinct dry seasons and hot, wet summer, enabling rapid population growth. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Climate variability in the SW Indian Ocean from an 8000-yr long multi-proxy record in the Mauritian lowlands shows a middle to late Holocene shift from negative IOD-state to ENSO-state

    NARCIS (Netherlands)

    De Boer, Erik J.; Tjallingii, Rik; Vélez, Maria I.; Rijsdijk, Kenneth F.; Vlug, Anouk; Reichart, Gert-Jan; Prendergast, Amy L.; de Louw, Perry G B; Florens, F. B Vincent; Baider, Cláudia; Hooghiemstra, Henry

    2014-01-01

    A multi-proxy reconstruction of a sediment core from the Tatos basin in the Mauritian lowlands reveals a dynamic environmental history during the last 8000 years. Under influence of sea level rise, the basin progressed from a wetland to a shallow lake between 8000 and 2500cal yr BP and it slowly

  15. Perceptions of the motivational climate, need satisfaction, and indices of well- and ill-being among hip hop dancers.

    Science.gov (United States)

    Quested, Eleanor; Duda, Joan L

    2009-01-01

    Grounded in the self-determination theoretical framework (SDT) formulated by Deci and Ryan, and specifically the basic needs mini-theory (BNT), this study examined the relationship between perceptions of the motivational climate manifested in hip hop environments, satisfaction of the three basic needs, and indicators of well- and ill-being among hip hop dancers. Fifty-nine hip hop dancers (mean age: 20.29 years) completed a questionnaire assessing the variables of interest in the study. Perceptions of a task-involving climate were positively associated with satisfaction of the needs for autonomy, competence, and relatedness. Perceptions of an ego-involving climate negatively predicted relatedness. Satisfaction of the need for competence was positively associated with positive affect, and negatively linked to negative affect. Competence need satisfaction significantly mediated the relationship between a perceived task-involving climate and positive and negative affective states. In sum, the findings provided partial support for the facets of SDT and BNT. The results also indicated that promoting the task-involving features of dance learning environments may be beneficial to dancers' well-being.

  16. Changes of Some Indices of Low Flow affected by Climate Change in the Tang Panj Sezar Basin

    Directory of Open Access Journals (Sweden)

    M. Mozayyan

    2016-10-01

    Full Text Available Introduction: Due to the effects of climate change on water resources and hydrology, Changes in low flow as an important part of the water cycle, is of interest to researchers, water managers and users in various fields. Changes in characteristics of low flows affected by climate change may have important effects on various aspects of socioeconomic , environmental, water resources and governmental planning. There are several indices to assess the low flows. The used low flow indices in this research for assessing climate change impacts, is include the extracted indices from flow duration curve (Q70, Q90 and Q95, due to the importance of these indices in understanding and assessing the status of river flow in dry seasons that was investigated in Tang Panj Sezar basin in the west of Iran. Materials and methods: In this paper, the Tang Panj Sezar basin with an area of 9410 km2 was divided into 6 smaller sub catchments and the changes of low flow indices were studied in each of the sub catchments. In order to consider the effects of climate change on low flow, scenarios of temperature and precipitation using 10 atmospheric general circulation models (to investigate the uncertainty of GCMs for both the baseline (1971-2000 and future (2011-2040 under A2 emission scenario was prepared. These scenarios, due to large spatial scale need to downscaling. Therefore, LARS-WG stochastic weather generator model was used. In order to consider the effects of climate change on low flows in the future, a hydrologic model is required to simulate daily flow for 2011-2040. The IHACRES rainfall-runoff model was used for this purpose . After simulation of daily flow using IHACRES, with two time series of daily flow for the observation and future period in each of the sub catchment, the low flow indices were compared. Results Discussion: According to results, across the whole year, the monthly temperature in the future period has increased while rainfall scenarios show

  17. Prioritizing key resilience indicators to support coral reef management in a changing climate.

    Directory of Open Access Journals (Sweden)

    Tim R McClanahan

    Full Text Available Managing coral reefs for resilience to climate change is a popular concept but has been difficult to implement because the empirical scientific evidence has either not been evaluated or is sometimes unsupportive of theory, which leads to uncertainty when considering methods and identifying priority reefs. We asked experts and reviewed the scientific literature for guidance on the multiple physical and biological factors that affect the ability of coral reefs to resist and recover from climate disturbance. Eleven key factors to inform decisions based on scaling scientific evidence and the achievability of quantifying the factors were identified. Factors important to resistance and recovery, which are important components of resilience, were not strongly related, and should be assessed independently. The abundance of resistant (heat-tolerant coral species and past temperature variability were perceived to provide the greatest resistance to climate change, while coral recruitment rates, and macroalgae abundance were most influential in the recovery process. Based on the 11 key factors, we tested an evidence-based framework for climate change resilience in an Indonesian marine protected area. The results suggest our evidence-weighted framework improved upon existing un-weighted methods in terms of characterizing resilience and distinguishing priority sites. The evaluation supports the concept that, despite high ecological complexity, relatively few strong variables can be important in influencing ecosystem dynamics. This is the first rigorous assessment of factors promoting coral reef resilience based on their perceived importance, empirical evidence, and feasibility of measurement. There were few differences between scientists' perceptions of factor importance and the scientific evidence found in journal publications but more before and after impact studies will be required to fully test the validity of all the factors. The methods here will

  18. Snow depth as an indicator of weather and climate in the Sierra Nevada

    OpenAIRE

    Riddle, Larry G.; Cayan, Daniel R.; Aguado, Edward

    1992-01-01

    EXTRACT (SEE PDF FOR FULL ABSTRACT): The purpose of this study is to determine: (1) whether the cooperative station snow depth contains useful weather and climate information, (2) how cooperative snow depth variability is related to snowcourse variability, and (3) how it is related to other weather elements. From an examination of stations in the Sierra Nevada of California, it is clear that cooperative snow records and snowcourse records have consistent spatial and temporal variability. ...

  19. The Skuta glacier as an indicator of climate changes in Slovenian part of the Alps

    Directory of Open Access Journals (Sweden)

    Miha Pavšek

    2007-12-01

    Full Text Available The Anton Melik Geographical Institute SRC SASA provide the regular annual measurements of Triglav and Skuta glaciers for more than six decades. Both glaciers show a permanent retreat. Last measurements undoubtedly confirm the importance of the glacier shady position at the foothills of the surrounding walls. Comparison of glacier characteristics with some meteorological data helps us to recognize the influence of climate changes on this, most southeastern lying glaciers in the Alps.

  20. Changes of benthic fauna in the Kattegat - An indication of climate change at mid-latitudes?

    Science.gov (United States)

    Göransson, Peter

    2017-07-01

    Several predictions point to changes in the marine benthic macrofauna associated with climate change, but so far only a few and minor changes have been reported. This study relates observed changes in the species composition to climate change by looking on the past decades in the Kattegat between Denmark and Sweden. A reduction of the total number species and a reduction of species with a northern range parallel to an increase of species with a southern range have been observed. The most likely explanation of the changes is the increase in temperature of the bottom water. Increased temperature could change the species distributions but also decrease primary production which impacts recruitment and growth. Hypoxia and bottom trawling could also act synergistic in this process. A sparse occurrence of previously encountered Arctic-Boreal species and critical foundation species, which gives the area its special character, suggests a change in biodiversity and might therefore be designated as early warning signals of a warmer climate. The northern fauna below the halocline with limited capacity of dispersal and low reproduction potential, can be considered as sensitive with low adaptive capacity to climate change. Therefore, not only tropical and high-latitude species, but also benthos on deep bottoms at mid-latitudes, could be vulnerable to warming. As many species live at the edge of their range in the Kattegat, and also are dependent of distant recruitment, large scale changes will probably be detected here at an early stage. It is important to protect relatively undisturbed reference areas in the Kattegat for future studies, but also for preserving a large number of ecosystem services, biotopes, habitats, and fish species.

  1. Prioritizing key resilience indicators to support coral reef management in a changing climate.

    Science.gov (United States)

    McClanahan, Tim R; Donner, Simon D; Maynard, Jeffrey A; MacNeil, M Aaron; Graham, Nicholas A J; Maina, Joseph; Baker, Andrew C; Alemu I, Jahson B; Beger, Maria; Campbell, Stuart J; Darling, Emily S; Eakin, C Mark; Heron, Scott F; Jupiter, Stacy D; Lundquist, Carolyn J; McLeod, Elizabeth; Mumby, Peter J; Paddack, Michelle J; Selig, Elizabeth R; van Woesik, Robert

    2012-01-01

    Managing coral reefs for resilience to climate change is a popular concept but has been difficult to implement because the empirical scientific evidence has either not been evaluated or is sometimes unsupportive of theory, which leads to uncertainty when considering methods and identifying priority reefs. We asked experts and reviewed the scientific literature for guidance on the multiple physical and biological factors that affect the ability of coral reefs to resist and recover from climate disturbance. Eleven key factors to inform decisions based on scaling scientific evidence and the achievability of quantifying the factors were identified. Factors important to resistance and recovery, which are important components of resilience, were not strongly related, and should be assessed independently. The abundance of resistant (heat-tolerant) coral species and past temperature variability were perceived to provide the greatest resistance to climate change, while coral recruitment rates, and macroalgae abundance were most influential in the recovery process. Based on the 11 key factors, we tested an evidence-based framework for climate change resilience in an Indonesian marine protected area. The results suggest our evidence-weighted framework improved upon existing un-weighted methods in terms of characterizing resilience and distinguishing priority sites. The evaluation supports the concept that, despite high ecological complexity, relatively few strong variables can be important in influencing ecosystem dynamics. This is the first rigorous assessment of factors promoting coral reef resilience based on their perceived importance, empirical evidence, and feasibility of measurement. There were few differences between scientists' perceptions of factor importance and the scientific evidence found in journal publications but more before and after impact studies will be required to fully test the validity of all the factors. The methods here will increase the feasibility

  2. The use of climatic parameters and indices in vegetation distribution. A case study in the Spanish Sistema Central.

    Science.gov (United States)

    Gavilán, Rosario G

    2005-11-01

    In this study, over 100 phytoclimatic indices and other climatic parameters were calculated using the climatic data from 260 meteorological stations in a Mediterranean territory located in the centre of the Iberian Peninsula. The nature of these indices was very different; some of them expressed general climatic features (e.g. continentality), while others were formulated for different Mediterranean territories and included particular limits of those indices that expressed differences in vegetation distribution. We wanted to know whether all of these indices were able to explain changes in vegetation on a spatial scale, and whether their boundaries worked similarly to the original territory. As they were so numerous, we investigated whether any of them were redundant. To relate vegetation to climate parameters we preferred to use its hierarchical nature, in discrete units (characterized by one or more dominant or co-dominant species), although it is known to vary continuously. These units give clearer results in this kind of phytoclimatic study. We have therefore used the main communities that represent natural potential vegetation. Multivariate and estimative analyses were used as statistical methods. The classification showed different levels of correlation among climatic parameters, but all of them were over 0.5. One hundred and eleven parameters were grouped into five larger groups: temperature (T), annual pluviothermic indices (PTY), summer pluviothermic indices (SPT), winter potential evapotranspiration (WPET) and thermal continentality indices (K). The remaining parameters showed low correlations with these five groups; some of them revealed obvious spatial changes in vegetation, such as summer hydric parameters that were zero in most vegetation types but not in high mountain vegetation. Others showed no clear results. For example, the Kerner index, an index of thermal continentality, showed lower values than expected for certain particular types of

  3. Cryolitozone of Mars- as the climatic indicator of the Martian relict ocean

    Science.gov (United States)

    Ozorovich, Y.; Fournier-Sicre, A.; Linkin, V.; Kosov, A.; Skulachev, D.; Gorbatov, S.; Ivanov, A.; Heggy, E.

    2015-10-01

    The existance of a large Martian cryolitozone consisting of different cryogenic formations both on the surface- polar caps ice and in subsurface layer (and probably overcooled salt solutions in lower horizons) is conditioned mostly by the planet's geological history and atmosphere evolution. The very structure of the cryolitozone with its strongly pronounced zone character owing to drying up of 0 to 200 m thick surface layer in the equatorial latitudes ranging from + 30 to - 300 was formed in the course of long-periodic climatic variations and at present is distincly heterogeneous both depthward and in latitudinal and longtudinal dimensions. The dryed up region of Martian frozen rocks is estimated to have been developing during more than 3.5 bln years, so the upper layer boundary of permafrost can serve as a sort of indicator reflecting the course of Martian climatic evolution. Since the emount of surface moisture and its distribition character are conditioned by the cryolitozone scale structure its investigation is considered to be an important aspect of the forthcoming Martian projects. In order to create Martian climate and atmosphere circulation models the whole complex information on surface provided by optical and infrared ranges observations, regional albedo surface measurements, ground layer thermal flow investigations, etc. must be carefully studed. The investigation of permafrost formation global distribution and their appearance in h ≤1 m thick subsurface layer may be provided successfully by using active-passive microwave remote sensing techniques [1]. Along with optical and infrared observations the method of orbital panoramic microwave radiometry in centi- and decimeter ranges would contribute to the mapping of the cryolitozone global surface distribution. This proposal discusses methodical and experimental possibilities of this global observation of Martian cryolitozone as the additional way for investigation subsurface of Mars. The main idea of

  4. Air pollution, climate, soil acidity, and indicators of forest health in Ontario's sugar maple forests

    Energy Technology Data Exchange (ETDEWEB)

    Miller, D.E.; Watmough, S.A. [Trent Univ., Peterborough, ON (Canada). Environmental and Resource Studies

    2009-11-15

    Despite a 50 per cent reduction in sulphur dioxide emissions and various policies that have been implemented over the past 2 decades to reduce air pollution, southern Ontario still receives the highest levels of air pollution in Canada. Although several monitoring programs have been established to evaluate the impacts of air pollution on the terrestrial environment, the impacts may be difficult to detect if they are mediated by soil chemistry or climate because gradients in soil chemistry and climate contrast with air pollution exposure. In this study, 35 hardwood plots were sampled in order to determine how contrasting stressors can be impacting the health of Ontario's sugar maple forests. The objectives of the study were to evaluate whether sugar maple canopy condition is related to indices of air pollution (S, N or O{sub 3}), climate or soil acidity; investigate whether other ecosystem components such as foliar chemistry or forest floor chemistry have a relationship with air pollution; and investigate whether potential thresholds of air pollution, climate or soil chemistry can be related to abrupt changes in forest ecosystem health or nutrients. Foliar sulfur and nitrogen contents were positively correlated with modeled deposition, and foliose lichen species richness was negatively correlated with modeled air pollution levels, whereas foliar calcium, magnesium, and manganese contents were correlated with A-horizon soil acidity. Forest floor S and N contents and C/N ratios were related to soil pH, with high S and N contents and low C/N ratios occurring on the more acidic soil in the northern part of the region. It was concluded that forest health as determined by canopy condition is not related to indices of air pollution, climate, or soil acidity. There was no relationship among air pollution, soil acidity, and ground vegetation species richness or diversity. 66 refs., 4 tabs., 10 figs.

  5. Towards an Event Based Indicator for Monitoring Change in Extreme Precipitation in Support of the US National Climate Assessment

    Science.gov (United States)

    Slinskey, E. A.; Loikith, P. C.; Waliser, D. E.

    2016-12-01

    Extreme precipitation events are associated with numerous societal and environmental impacts. Recent observational analysis suggests increasing trends in precipitation intensity across portions of the Continental United States (CONUS) consistent with expectations associated with anthropogenic climate change. Therefore, a spatial understanding and intuitive means of monitoring extreme precipitation over time is critical. In support of the ongoing efforts of the US National Climate Assessment (NCA), we present a gridded climate indicator, based on high-resolution gridded NASA satellite-based precipitation data from NASA's Tropical Rainfall Measuring Mission (TRMM) and the Global Precipitation Measurement (GPM) product, to monitor and track extreme precipitation events over the CONUS. The indicator is based on categorized storm totals over the CONUS defined as 3-day total accumulated precipitation events, ensuring a spatially and temporally balanced regional representation of synoptic-scale and short-duration storm events alike. A precipitation categorization scheme mirroring that of the widely understood Saffir-Simpson hurricane intensity index is assigned to each 3-day precipitation event with each precipitation category referred to as a P-Cat. The magnitude of each event lies between P-Cat 1, the lightest category of storm totals, and P-Cat 5, the heaviest, allowing for easy interpretation and visualization. With all precipitation events assigned to a P-Cat, point-wise statistics are computed across the CONUS including the maximum P-Cat, the mean P-Cat, and the frequency of each P-Cat at each grid point providing a comprehensive climatology of precipitation event intensity and a baseline for monitoring change. A novel aspect of this indicator is that it will accurately display discernable spatial variations with regional specificity in extreme precipitation event frequency and intensity over relevant temporal scales. Changes in variability will be observable at

  6. Subkurgan Paleosoils of the Lower Volga Steppes as Indicators of Climate Dynamics over an Historical Epoch

    Directory of Open Access Journals (Sweden)

    Demkin Vitaliy A.

    2013-06-01

    Full Text Available The studies of paleosoils buried beneath burial mounds of the Early, Middle, and Late Sarmatian time (4th c. BC to 4th c. AD were carried out in the dry and desert steppes of the Lower Volga river area (the Volga and Yergenino uplands, the Caspian lowland. It was established that within the chronological interval of 2400–1600 years ago temporal variability of morphological, chemical, microbiological, and magnetic properties of paleosoils was rhythmical, being conditioned by the centennial dynamics of climate humidity with oscillations of mean annual precipitation rate within ±30–50 mm. The periodic change of humid and arid climatic epochs considerably influenced soil salinization-desalinization, solonetz and humus formation processes, and biological activity of paleosoils of the solonetz alkali soil complexes. This stimulated essential changes in the structure of the soil covering with reversal evolutionary transformations of paleosoils on the levels of types, genera or species within several decades. The natural conditions within the existence of the Sarmatian culture society may be characterized as alternation of micropluvial and microarid periods with 100–200-year duration. In particular, both in dry (Volga-Don interfluve and in desert (Trans-Volga steppes, the 1st c. BC, AD 1st and 4th cc. were characterized by relatively humid conditions, while the 4th–3rd cc. BC and second half of the 2nd to first half of the 3rd cc. AD were most arid. Intermediate humidity situation close to modern time was characteristic of the period from the first half of the 2nd to the second half of 3rd century AD. The evolution of climatic conditions is generally consistent with the rhythms of natural processes in other steppe and desert regions of Eurasia.

  7. Climate-Driven or Human-Induced: Indicating Severe Water Scarcity in the Moulouya River Basin (Morocco

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    Vera Tekken

    2012-12-01

    Full Text Available Many agriculture-based economies are increasingly under stress from climate change and socio-economic pressures. The excessive exploitation of natural resources still represents the standard procedure to achieve socio-economic development. In the area of the Moulouya river basin, Morocco, natural water availability represents a key resource for all economic activities. Agriculture represents the most important sector, and frequently occurring water deficits are aggravated by climate change. On the basis of historical trends taken from CRU TS 2.1, this paper analyses the impact of climate change on the per capita water availability under inclusion of population trends. The Climatic Water Balance (CWB shows a significant decrease for the winter period, causing adverse effects for the main agricultural season. Further, moisture losses due to increasing evapotranspiration rates indicate problems for the annual water budget and groundwater recharge. The per capita blue water availability falls below a minimum threshold of 500 m3 per year, denoting a high regional vulnerability to increasing water scarcity assuming a no-response scenario. Regional development focusing on the water-intense sectors of agriculture and tourism appears to be at risk. Institutional capacities and policies need to address the problem, and the prompt implementation of innovative water production and efficiency measures is recommended.

  8. URBAN AND ARCHITECTURAL SUSTAINABILITY INDICATORS USE ENERGY HOT CLIMATE AREAS IN ALGERIA

    Directory of Open Access Journals (Sweden)

    Labdi DARAF

    2016-06-01

    Full Text Available The large increase in population leads to an increase in rates of conventional consumption of energy, especially electrical energy of the same percentage and more. As a result, the focus is on the global search for ways to preserve the traditional energy sources and rational use. In recent years, Algeria has adopted a construction policy to meet the needs of the increasing demands on the field of housing by massive housing project represented in the neighborhood groups because of their economic characteristics in the provision of real estate. In recent years, the rates of energy demand have increased with the widespread use of air conditioners, despite the presence of the natural solutions to reduce this kind of problems. Generally, The Algerian climate considered as a hot one, which is characterized by the drought. Therefore the construction should requires such properties and elements suitable for this climate. Those strategies and trends may based on the return to techniques and mechanisms that were used in the traditional environmental construction, which is considered as a basic reference that led to the development of many solutions and technologies for sustainable development benefiting from the accumulation of the previous civilizations over centuries. The aim of this research is to determine the curriculum calendar of the thermal performance for the housing in the collective areas, hot semi-arid, to set standards may used in evaluating the prevailing performance in the architectural planning and design for residential neighborhoods which reflected on the population in terms of the consumption energy.

  9. Climate and land-use change impact on faecal indicator bacteria in a temperate maritime catchment (the River Conwy, Wales)

    Science.gov (United States)

    Bussi, Gianbattista; Whitehead, Paul G.; Thomas, Amy R. C.; Masante, Dario; Jones, Laurence; Jack Cosby, B.; Emmett, Bridget A.; Malham, Shelagh K.; Prudhomme, Christel; Prosser, Havard

    2017-10-01

    Water-borne pathogen contamination from untreated sewage effluent and runoff from farms is a serious threat to the use of river water for drinking and commercial purposes, such as downstream estuarine shellfish industries. In this study, the impact of climate change and land-use change on the presence of faecal indicator bacteria in freshwater was evaluated, through the use of a recently-developed catchment-scale pathogen model. The River Conwy in Wales has been used as a case-study, because of the large presence of livestock in the catchment and the importance of the shellfish harvesting activities in its estuary. The INCA-Pathogens catchment model has been calibrated through the use of a Monte-Carlo-based technique, based on faecal indicator bacteria measurements, and then driven by an ensemble of climate projections obtained from the HadRM3-PPE model (Future Flow Climate) plus four land-use scenarios (current land use, managed ecosystem, abandonment and agricultural intensification). The results show that climate change is not expected to have a very large impact on average river flow, although it might alter its seasonality. The abundance of faecal indicator bacteria is expected to decrease in response to climate change, especially during the summer months, due to reduced precipitation, causing reduced runoff, and increased temperature, which enhances the bacterial die-off processes. Land-use change can also have a potentially large impact on pathogens. The "managed ecosystems" scenario proposed in this study can cause a reduction of 15% in average water faecal indicator bacteria and up to 30% in the 90th percentile of water faecal indicator bacteria, mainly due to the conversion of pasture land into grassland and the expansion of forest land. This study provides an example of how to assess the impacts of human interventions on the landscape, and what may be the extent of their effects, for other catchments where the human use of the natural resources in the

  10. Qualitative and Quantitative Sentiment Proxies

    DEFF Research Database (Denmark)

    Zhao, Zeyan; Ahmad, Khurshid

    2015-01-01

    Sentiment analysis is a content-analytic investigative framework for researchers, traders and the general public involved in financial markets. This analysis is based on carefully sourced and elaborately constructed proxies for market sentiment and has emerged as a basis for analysing movements...... and trading volumes. The case study we use is a small market index (Danish Stock Exchange Index, OMXC 20, together with prevailing sentiment in Denmark, to evaluate the impact of sentiment on OMXC 20. Furthermore, we introduce a rather novel and quantitative sentiment proxy, that is the use of the index...

  11. Future change of extreme temperature climate indices over East Asia with uncertainties estimation in the CMIP5

    Science.gov (United States)

    Seo, Ye-Won; Kim, Hojin; Yun, Kyung-Sook; Lee, June-Yi; Ha, Kyung-Ja; Moon, Ja-Yeon

    2014-11-01

    How well the climate models simulate extreme temperature over East Asia and how the extreme indices would change under anthropogenic global warming are investigated. The indices studied include hot days (HD), tropical nights (TN), growing degree days (GDD), and cooling degree days (CDD) in summer and heating degree days (HDD) and frost days (FD) in winter. The representative concentration pathway 4.5 (RCP 4.5) experiments for the period of 2075-2099 are compared with historical simulations for the period of 1979-2005 from 15 coupled models that are participated in phase 5 of the Coupled Model Intercomparison Project (CMIP5). To optimally estimate future change and its uncertainty, groups of best models are selected based on Taylor diagrams, relative entropy, and probability density function (PDF) methods previously suggested. Overall, the best models' multi-model ensemble based on Taylor diagrams has the lowest errors in reproducing temperature extremes in the present climate among three methods. Selected best models in three methods tend to project considerably different changes in the extreme indices from each other, indicating that the selection of reliable models are of critical importance to reduce uncertainties. Three groups of best models show significant increase of summerbased indices but decrease of the winter-based indices. Over East Asia, the most significant increase is seen in the HD (336 ± 23.4% of current climate) and the most significant decrease is appeared in the HDD (82 ± 4.2%). It is suggested that the larger future change in the HD is found over in the Southeastern China region, probably due to a higher local maximum temperature in the present climate. All of the indices show the largest uncertainty over Southeastern China, particularly in the TN (~3.9 times as large as uncertainty over East Asia) and in the HD (~2.4). It is further noted that the TN reveals the largest uncertainty over three East Asian countries (~1.7 and 1.4 over Korea and

  12. Recommendations for the Regionalizing of Coffee Cultivation in Colombia: A Methodological Proposal Based on Agro-Climatic Indices

    Science.gov (United States)

    García L., Juan Carlos; Posada-Suárez, Húver; Läderach, Peter

    2014-01-01

    The Colombian National Federation of Coffee Growers (FNC) conducted an agro-ecological zoning study based on climate, soil, and terrain of the Colombian coffee-growing regions (CCGR) located in the tropics, between 1° and 11.5° N, in areas of complex topography. To support this study, a climate baseline was constructed at a spatial resolution of 5 km. Twenty-one bioclimatic indicators were drawn from this baseline data and from yield data for different coffee genotypes evaluated under conditions at eight experimental stations (ESs) belonging to the National Center for Coffee Research (CENICAFÉ). Three topographic indicators were obtained from a digital elevation model (DEM). Zoning at a national level resulted in the differentiation of 12 agro-climatic zones. Altitude notably influenced zone differentiation, however other factors such as large air currents, low-pressure atmospheric systems, valleys of the great rivers, and physiography also played an important role. The strategy of zoning according to coffee-growing conditions will enable areas with the greatest potential for the development of coffee cultivation to be identified, criteria for future research to be generated, and the level of technology implementation to be assessed. PMID:25436456

  13. A healthy turn in urban climate change policies; European city workshop proposes health indicators as policy integrators.

    Science.gov (United States)

    Keune, Hans; Ludlow, David; van den Hazel, Peter; Randall, Scott; Bartonova, Alena

    2012-06-28

    The EU FP6 HENVINET project reviewed the potential relevance of a focus on climate change related health effects for climate change policies at the city region level. This was undertaken by means of a workshop with both scientists, city representatives from several EU-countries, representatives of EU city networks and EU-experts. In this paper we introduce some important health related climate change issues, and discuss the current city policies of the participating cities. The workshop used a backcasting format to analyse the future relevance of a health perspective, and the main benefits and challenges this would bring to urban policy making. It was concluded that health issues have an important function as indicators of success for urban climate change policies, given the extent to which climate change policies contribute to public health and as such to quality of life. Simultaneously the health perspective may function as a policy integrator in that it can combine several related policy objectives, such as environmental policies, health policies, urban planning and economic development policies, in one framework for action. Furthermore, the participants to the workshop considered public health to be of strategic importance in organizing public support for climate change policies. One important conclusion of the workshop was the view that the connection of science and policy at the city level is inadequate, and that the integration of scientific knowledge on climate change related health effects and local policy practice is in need of more attention. In conclusion, the workshop was viewed as a constructive advance in the process of integration which hopefully will lead to ongoing cooperation. The workshop had the ambition to bring together a diversity of actor perspectives for exchange of knowledge and experiences, and joint understanding as a basis for future cooperation. Next to the complementarities in experience and knowledge, the mutual critical reflection

  14. Objective Use of Climate Indices to Inform Ensemble Streamflow Forecasts in the Columbia River Basin - An Initial Review

    Science.gov (United States)

    Pytlak, E.; McManamon, A.; Hughes, S. P.; Van Der Zweep, R. A.; Butcher, P.; Karafotias, C.; Beckers, J.; Welles, E.

    2016-12-01

    Numerous studies have documented the impacts that large scale weather patterns and climate phenomenon like the El Niño Southern Oscillation (ENSO), Pacific-North American (PNA) Pattern, and others can have on seasonal temperature and precipitation in the Columbia River Basin (CRB). While far from perfect in terms of seasonal predictability in specific locations, these intra-annual weather and climate signal do tilt the odds toward different temperature and precipitation outcomes, which in turn can have impacts on seasonal snowpacks, streamflows and water supply in large river basins like the CRB. We hypothesize that intraseasonal climate signals and long wave jet stream patterns can be objectively incorporated into what it is otherwise a climatology-based set of Ensemble Streamflow Forecasts, and can increase the predictive skill and utility of these forecasts used for mid-range hydropower planning. The Bonneville Power Administration (BPA) and Deltares have developed a subsampling-resampling method to incorporate climate mode information into the Ensemble Streamflow Prediction (ESP) forecasts (Beckers, et al., 2016). Since 2015, BPA and Deltares USA have experimented with this method in pre-operational use, using five objective multivariate climate indices that appear to have the greatest predictive value for seasonal temperature and precipitation in the CRB. The indices are used to objectively select historical weather from about twenty analog years in the 66-year (1949-2015) historical ESP set. These twenty scenarios then serve as the starting point to generate monthly synthetic weather and streamflow time series to return to a set of 66 streamflow traces. Our poster will share initial results from the 2015 and 2016 water years, which included large swings in the Quasi-Biennial Oscillation, persistent blocking jet stream patterns, and the development of a strong El Niño event. While the results are very preliminary and for only two seasons, there may be some

  15. Validation of Spacecraft Active Cavity Radiometer Total Solar Irradiance (TSI) Long Term Measurement Trends Using Proxy TSI Least Squares Analyses

    Science.gov (United States)

    Lee, Robert Benjamin, III; Wilson, Robert S.

    2003-01-01

    Long-term, incoming total solar irradiance (TSI) measurement trends were validated using proxy TSI values, derived from indices of solar magnetic activity. Spacecraft active cavity radiometers (ACR) are being used to measure longterm TSI variability, which may trigger global climate changes. The TSI, typically referred to as the solar constant, was normalized to the mean earth-sun distance. Studies of spacecraft TSI data sets confirmed the existence of a 0.1 %, long-term TSI variability component within a 10-year period. The 0.1% TSI variability component is clearly present in the spacecraft data sets from the 1984-2004 time frame. Typically, three overlapping spacecraft data sets were used to validate long-term TSI variability trends. However, during the years of 1978-1984, 1989-1991, and 1993-1996, three overlapping spacecraft data sets were not available in order to validate TSI trends. The TSI was found to vary with indices of solar magnetic activity associated with recent 10-year sunspot cycles. Proxy TSI values were derived from least squares analyses of the measured TSI variability with the solar indices of 10.7-cm solar fluxes, and with limb-darked sunspot fluxes. The resulting proxy TSI values were compared to the spacecraft ACR measurements of TSI variability to detect ACR instrument degradation, which may be interpreted as TSI variability. Analyses of ACR measurements and TSI proxies are presented primarily for the 1984-2004, Earth Radiation Budget Experiment (ERBE) ACR solar monitor data set. Differences in proxy and spacecraft measurement data sets suggest the existence of another TSI variability component with an amplitude greater than or equal to 0.5 Wm-2 (0.04%), and with a cycle of 20 years or more.

  16. Nonstationarity in the occurrence rate of floods in the Tarim River basin, China, and related impacts of climate indices

    Science.gov (United States)

    Gu, Xihui; Zhang, Qiang; Singh, Vijay P.; Chen, Xi; Liu, Lin

    2016-07-01

    Amplification of floods in the Xinjiang, China, has been observed, but reports on their changing properties and underlying mechanisms are not available. In this study, occurrence rates of floods in the Tarim River basin, the largest inland arid river basin in China, were analyzed using the Kernel density estimation technique and bootstrap resampling method. Also analyzed were the occurrence rates of precipitation extremes using the POT (Peak over Threshold)-based sampling method. Both stationary and non-stationary models were developed using GAMLSS (Generalized Additive Models for Location, Scale and Shape) to model flood frequency with time, climate index, precipitation and temperature as major predictors. Results indicated: (1) two periods with increasing occurrence of floods, i.e., the late 1960s and the late 1990s with considerable fluctuations around 2-3 flood events during time intervals between the late 1960s and the late 1990s; (2) changes in the occurrence rates of floods were subject to nonstationarity. A persistent increase of flood frequency and magnitude was observed during the 1990s and reached a peak value; (3) AMO (Atlantic Multidecadal Oscillation) and AO (Atlantic Oscillation) in winter were the key influencing climate indices impacting the occurrence rates of floods. However, NAO (North Atlantic Oscillation) and SOI (South Oscillation Index) are two principle factors that influence the occurrence rates of regional floods. The AIC (Akaike Information Criterion) values indicated that compared to the influence of climate indices, occurrence rates of floods seemed to be more sensitive to temperature and precipitation changes. Results of this study are important for flood management and development of mitigation measures.

  17. Evaluating County-Level Heat Vulnerability and Social Inequity in the United States through Climate and Socioeconomic Indices

    Science.gov (United States)

    Gannon, C.

    2016-12-01

    Climate change will have many impacts on human health, perhaps most directly through extreme heat. High temperature and humidity combinations inhibit the body's ability to cool through physiological responses such as sweating. In conjunction with extended periods of extreme heat and shifted seasonality, these conditions are particularly dangerous. Current research and literature can be used to show where dangerous heat and humidity conditions are likely to be most prevalent, or where populations vulnerable to heat stress reside. To provide a better assessment of overall heat vulnerability, however, many complex factors, such as relative changes in temperature patterns or local socioeconomic conditions, must also be considered. Here, we utilize a multivariate approach to establish county-level risk scores by combining the most relevant indicators for heat vulnerability with climate model projections of wet bulb globe temperature, a metric useful for understanding how the human body will respond to conditions of high heat and humidity. We present our findings as an ESRI ArcOnline Story Map with data aggregated at the county-level in the continental United States. This format allows users to access maps showing each county's score in four categories related to heat vulnerability: heat and humidity hazards, population vulnerability, medical access, and physical infrastructure. A final map showcases a composite heat vulnerability score for each county, with comparisons to state and national averages. Our tool, part of the White House's Climate Data Initiative, is presented as a series of maps with a normalized scoring system to provide clear and easy access to the indicators most relevant to evaluating heat vulnerability at a local level. Ultimately, this readily available tool with general indices helps community decision makers communicate heat vulnerability and identify which resilience factors are most critical to improving local resilience.

  18. Gauging climate change effects at local scales: weather-based indices to monitor insect harassment in caribou.

    Science.gov (United States)

    Witter, Leslie A; Johnson, Chris J; Croft, Bruno; Gunn, Anne; Poirier, Lisa M

    2012-09-01

    Climate change is occurring at an accelerated rate in the Arctic. Insect harassment may be an important link between increased summer temperature and reduced body condition in caribou and reindeer (both Rangifer tarandus). To examine the effects of climate change at a scale relevant to Rangifer herds, we developed monitoring indices using weather to predict activity of parasitic insects across the central Arctic. During 2007-2009, we recorded weather conditions and used carbon dioxide baited traps to monitor activity of mosquitoes (Culicidae), black flies (Simuliidae), and oestrid flies (Oestridae) on the post-calving and summer range of the Bathurst barren-ground caribou (Rangifer tarandus groenlandicus) herd in Northwest Territories and Nunavut, Canada. We developed statistical models representing hypotheses about effects of weather, habitat, location, and temporal variables on insect activity. We used multinomial logistic regression to model mosquito and black fly activity, and logistic regression to model oestrid fly presence. We used information theory to select models to predict activity levels of insects. Using historical weather data, we used hindcasting to develop a chronology of insect activity on the Bathurst range from 1957 to 2008. Oestrid presence and mosquito and black fly activity levels were explained by temperature. Wind speed, light intensity, barometric pressure, relative humidity, vegetation, topography, location, time of day, and growing degree-days also affected mosquito and black fly levels. High predictive ability of all models justified the use of weather to index insect activity. Retrospective analyses indicated conditions favoring mosquito activity declined since the late 1950s, while predicted black fly and oestrid activity increased. Our indices can be used as monitoring tools to gauge potential changes in insect harassment due to climate change at scales relevant to caribou herds.

  19. Hemispheric ozone variability indices derived from satellite observations and comparison to a coupled chemistry-climate model

    Directory of Open Access Journals (Sweden)

    T. Erbertseder

    2006-01-01

    Full Text Available Total column ozone is used to trace the dynamics of the lower and middle stratosphere which is governed by planetary waves. In order to analyse the planetary wave activity a Harmonic Analysis is applied to global multi-year total ozone observations from the Total Ozone Monitoring Spectrometer (TOMS. As diagnostic variables we introduce the hemispheric ozone variability indices one and two. They are defined as the hemispheric means of the amplitudes of the zonal waves number one and two, respectively, as traced by the total ozone field. The application of these indices as a simple diagnostic for the evaluation of coupled chemistry-climate models (CCMs is demonstrated by comparing results of the CCM ECHAM4.L39(DLR/CHEM (hereafter: E39/C against satellite observations. It is quantified to what extent a multi-year model simulation of E39/C (representing "2000" climate conditions is able to reproduce the zonal and hemispheric planetary wave activity derived from TOMS data (1996–2004, Version 8. Compared to the reference observations the hemispheric ozone variability indices one and two of E39/C are too high in the Northern Hemisphere and too low in the Southern Hemisphere. In the Northern Hemisphere, where the agreement is generally better, E39/C produces too strong a planetary wave one activity in winter and spring and too high an interannual variability. For the Southern Hemisphere we reveal that the indices from observations and model differ significantly during the ozone hole season. The indices are used to give reasons for the late formation of the Antarctic ozone hole, the insufficient vortex elongation and eventually the delayed final warming in E39/C. In general, the hemispheric ozone variability indices can be regarded as a simple and robust diagnostic to quantify model-observation differences concerning planetary wave activity. It allows a first-guess on how the dynamics is represented in a model simulation before applying costly and more

  20. Indicators for Assessing Climate Change Resilience Resulting from Emplacement of Green Infrastructure Projects Across an Urban Landscape

    Science.gov (United States)

    Parish, E. S.; Omitaomu, O.; Sylvester, L.; Nugent, P.

    2015-12-01

    Many U.S. cities are exploring the potential of using green infrastructure (e.g., porous pavements, green roofs, street planters) to reduce urban storm water runoff, which can be both be a nuisance and costly to treat. While tools exist to measure local runoff changes resulting from individual green infrastructure (GI) projects, most municipalities currently have no method of analyzing the collective impact of GI projects on urban stormwater systems under future rainfall scenarios and impervious surface distribution patterns. Using the mid-sized city of Knoxville, Tennessee as a case study, we propose a set of indicators that can be used to monitor and analyze the collective effects of GI emplacement on urban storm water runoff volumes as well as to quantify potential co-benefits of GI projects (e.g., urban heat island reduction, reduced stream scouring) under different climate projection ensembles and population growth scenarios. These indicators are intended to help the city prioritize GI projects as opportunities arise, as well as to track the effectiveness of GI implementation over time. We explore the aggregation of these indicators across different spatial scales (e.g., plot, neighborhood, watershed, city) in order to assess potential changes in climate change resilience resulting from the collective implementation of GI projects across an urban landscape.

  1. Investigation of temperature and its indices under climate change scenarios over different regions of Rajasthan state in India

    Science.gov (United States)

    Sharma, Aditya; Sharma, Devesh; Panda, S. K.; Dubey, Swatantra Kumar; Pradhan, Rajani K.

    2018-02-01

    The ongoing increases in concentrations of atmospheric greenhouse gas will most likely affect global climate for the rest of this century. Global warming brings a huge provocation to society and human beings. Single extreme events and increased climate variability have a greater impact than long-term changes in the mean of climatic variables. This study analyzed the temperature projections for Rajasthan state, India using data obtain from two General Circulation Models (GFCM21 and HadCM3) for three Intergovernmental Panel on Climate Change (IPCC) Special Range of Emission Scenarios (SRES) A1B, A2, and B1. A 30 years of maximum (Tmax) and minimum (Tmin) temperature for the period 1976-2005 has been obtained from India Meteorological Department (IMD) and by using LARS-WG5 to generate the long-term weather series for three different periods i.e. 2011-2040 (2025s), 2041-2070 (2055s), and 2071-2100 (2085s). Further to determine the changes in extreme temperature events, the data for the baseline period and the future periods was represented by eight extreme temperature indices. Results illustrate that an increase in minimum and the maximum temperature are observed in all the three future periods. The average mean temperature for base period and three future periods over four regions of Rajasthan was observed highest in region 3 which shows an incessantly increased in mean temperature about 2.6 °C i.e. north-east and north-west part of Rajasthan. Two GCMs depicts that the incessant temperatures may be increase in the future and future maximum temperature in all the seasons varies from 2.43 °C to 4.27 °C in the direction from south to north of Rajasthan during 2071-2100. While for minimum temperature, the range of temperature changes varies from 0.23 °C to 1.42 °C from south-east to north-west of Rajasthan during 2011-2040. In the temperature indices, the number of tropical nights (TR20), warmest day (TX90p), warmest night (TN90p) and summer days (SU25) is expected

  2. Recent trends in Inner Asian forest dynamics to temperature and precipitation indicate high sensitivity to climate change

    Science.gov (United States)

    Poulter, B.; Pederson, N.; Liu, H.; Zhu, Z.; D'Arrigo, R.; Ciais, P.; Davi, N.; Frank, D. C.; Leland, C.; Myneni, R.; Piao, S.; Wang, T.

    2012-12-01

    Semi-arid ecosystems play an important role in regulating global climate and their response to climate change will depend on interactions between temperature, precipitation, and CO2. However, in cool-arid environments, precipitation is not the only limitation to forest productivity. For example, interactions between changes in precipitation and air temperature may enhance soil moisture stress while simultaneously extending growing season length, with unclear consequences for net carbon uptake. This presentation evaluates recent trends in productivity and seasonality of forests located in Inner Asia (Mongolia and Northern China) using satellite remote sensing, dendrochronology, and dynamic global vegetation model (DGVM) simulations to quantify the sensitivity of forest dynamics to decadal climate variability and trends. Long-term trends from satellite observations of FPAR between 1982-2010 show a greening of 21% of the region in spring (March, April May), but with 10% of the area 'browning' during summertime (June, July, August), the results of which are corroborated by trends in NPP simulated by the LPJ DGVM. Spring greening trends in FPAR are mainly explained by long-term trends in precipitation whereas summer browning trends are correlated with decreasing precipitation. Tree ring data from 25 sites confirm annual growth increments are mainly limited by summer precipitation (June, July, August) in Mongolia, and spring precipitation in northern China (March, April, May), with relatively weak prior-year lag effects. An ensemble of climate projections from the IPCC CMIP3 models indicates that warming temperatures (spring, summer) are expected to be associated with higher summer precipitation, which combined with CO2 causes large increases in NPP and eventual increase in forest cover in the Mongolian steppe. In the absence of a strong direct CO2 fertilization effect on plant growth (e.g., due to nutrient limitation), water stress or decreased carbon gain from higher

  3. How different proxies record precipitation variability over southeastern South America

    Energy Technology Data Exchange (ETDEWEB)

    Chiessi, Cristiano M; Mulitza, Stefan; Paetzold, Juergen; Wefer, Gerold, E-mail: chiessi@uni-bremen.d [MARUM-Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, 28359 Bremen (Germany)

    2010-03-15

    Detrending natural and anthropogenic components of climate variability is arguably an issue of utmost importance to society. To accomplish this issue, one must rely on a comprehensive understanding of the natural variability of the climate system on a regional level. Here we explore how different proxies (e.g., stalagmite oxygen isotopic composition, pollen percentages, bulk sediment elemental ratios) record Holocene precipitation variability over southeastern South America. We found a general good agreement between the different records both on orbital and centennial time-scales. Dry mid Holocene, and wet late Holocene, Younger Dryas and a period between {approx}9.4 and 8.12 cal kyr BP seem to be pervasive features. Moreover, we show that proxy-specific sensitivity can greatly improve past precipitation reconstructions.

  4. Inter-annual climate variability and zooplankton: applying teleconnection indices to two deep subalpine lakes in Italy

    Directory of Open Access Journals (Sweden)

    Marina Manca

    2014-08-01

    Full Text Available Investigating relation between meteo-climatic indices and between-year variation in Daphnia population density and phenology is crucial for e.g. predicting impact of climate change on lake ecosystem structure and functioning. We tested whether and how two teleconnection indices calculated for the winter period, namely the East Atlantic pattern (EADJF and the Eastern Mediterranean Pattern (EMPDJF were correlated with Daphnia population growth in two Italian subalpine lakes, Garda and Maggiore. We investigated between-lake temporal coherence in: i water temperature within the water layer in which Daphnia is distributed; ii timing of Daphnia initial and spring maximum population density peak and iii the level of Daphnia spring maximum population density peak over an eleven-year period (1998-2008 of unchanged predation pressure by fish and invertebrates, and of common oligotrophy. Between-lake temporal coherence was high for an earlier start, an earlier, and lower, Daphnia population spring density peak after milder winters. Peak density level was coherently, positively correlated with soluble reactive phosphorus (SRP concentration. We hypothesized that Daphnia peak densities were related to atmospheric modes of variability in winter and to the degree of late winter mixing promoting replenishment of algal nutrients into upper water layers and phytoplankton growth, enhancing food availability and Daphnia fecundity, promoting Daphnia peak. 

  5. REMOTELY-SENSED URBAN WET-LANDSCAPES: AN INDICATOR OF COUPLED EFFECTS OF HUMAN IMPACT AND CLIMATE CHANGE

    Directory of Open Access Journals (Sweden)

    W. Ji

    2016-06-01

    Full Text Available This study proposes the concept of urban wet-landscapes (loosely-defined wetlands as against dry-landscapes (mainly impervious surfaces. The study is to examine whether the dynamics of urban wet-landscapes is a sensitive indicator of the coupled effects of the two major driving forces of urban landscape change – human built-up impact and climate (precipitation variation. Using a series of satellite images, the study was conducted in the Kansas City metropolitan area of the United States. A rule-based classification algorithm was developed to identify fine-scale, hidden wetlands that could not be appropriately detected based on their spectral differentiability by a traditional image classification. The spatial analyses of wetland changes were implemented at the scales of metropolitan, watershed, and sub-watershed as well as based on the size of surface water bodies in order to reveal urban wetland change trends in relation to the driving forces. The study identified that wet-landscape dynamics varied in trend and magnitude from the metropolitan, watersheds, to sub-watersheds. The study also found that increased precipitation in the region in the past decades swelled larger wetlands in particular while smaller wetlands decreased mainly due to human development activities. These findings suggest that wet-landscapes, as against the dry-landscapes, can be a more effective indicator of the coupled effects of human impact and climate change.

  6. Munchausen syndrome by proxy: a case report.

    Science.gov (United States)

    Lieder, Holly S; Irving, Sharon Y; Mauricio, Rizalina; Graf, Jeanine M

    2005-01-01

    Munchausen syndrome by proxy is difficult to diagnose unless healthcare providers are astute to its clinical features and management. A case is presented to educate nurses and advanced practice nurses, of the nursing, medical, legal, and social complexities associated with Munchausen syndrome by proxy. This article also provides a brief review of the definition of Munchausen syndrome by proxy, its epidemiology, common features of the perpetrator, implications for healthcare personnel, and the legal and international ramifications of Munchausen syndrome by proxy.

  7. Trends in Extreme Climate Indices for Pará State, Brazil

    Directory of Open Access Journals (Sweden)

    Carlos Antonio Costa dos Santos

    Full Text Available Abstract The present study aimed to analyze trends in air temperature and rainfall for 13 locations in the state of Pará using nonparametric tests. Daily data of maximum and minimum air temperatures and precipitation covering the period 1970-2006, collected by the Instituto Nacional de Meteorologia (INMET have been used. From the results obtained it was observed that the number of warm days and nights per year has increased, thereby providing a significant reduction in the number of cool days and nights in the state. Due to the high space-time variability of precipitation, few localities showed statistically significant trends for indices of extremes dependent on this variable. The days and nights in Belém have been hotter in the last two decades. Therefore, these results are important for future planning of public health and energy for the state of Para, which must adapt to future warming scenarios sectors.

  8. Climate index for the Netherlands - Methodology; Indice climatique Pays-Bas methodologie

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    According to the U.S. Department of Energy, an estimated 25% of the GNP is affected by weather-related events. The variations in temperature - even small ones - can also have long-lasting effects on the operational results of a company. Among other, the Energy supply sector is sensitive to weather risks: a milder or harsher than usual winter leads to a decrease or increase of energy consumption. The price of electricity on power trading facilities like Powernext is especially sensitive to odd changes in temperatures. Powernext and Meteo-France (the French meteorological agency) have joined expertise in order to promote the use of weather indices in term of decision making or underlying of hedging tools to energy actors, end users from any other sector of activity and specialists of the weather risk hedging. The Powernext Weather indices are made from information collected by Meteo-France's main observation network according to the norms of international meteorology, in areas carefully selected. The gross data are submitted to a thorough review allowing the correction of abnormalities and the reconstitution of missing data. Each index is fashioned to take into account the economic activity in the various regions of the country as represented by each region's population. This demographic information represents a fair approximation of the weight of the regional economic activity. This document presents the calculation methodology of average, minimum and maximum weather indexes with the winter and summer regression equations for the different economical regions of the Netherlands. (J.S.)

  9. Shareholder Activism Through the Proxy Process

    NARCIS (Netherlands)

    Renneboog, L.D.R.; Szilagyi, P.G.

    2009-01-01

    This paper provides evidence on the corporate governance role of shareholder-initiated proxy proposals. Previous studies debate over whether activists use proxy proposals to discipline firms or to simply advance their self-serving agendas, and whether proxy proposals are effective at all in

  10. Shareholder Activism through the Proxy Process

    NARCIS (Netherlands)

    Renneboog, L.D.R.; Szilagyi, P.G.

    2009-01-01

    This paper provides evidence on the corporate governance role of shareholderinitiated proxy proposals. Previous studies debate over whether activists use proxy proposals to discipline firms or to simply advance their self-serving agendas, and whether proxy proposals are effective at all in

  11. Olive response to water availability: yield response functions, soil water content indicators and evaluation of adaptability to climate change

    Science.gov (United States)

    Riccardi, Maria; Alfieri, Silvia Maria; Basile, Angelo; Bonfante, Antonello; Menenti, Massimo; Monaco, Eugenia; De Lorenzi, Francesca

    2013-04-01

    Climate evolution, with the foreseen increase of temperature and frequency of drought events during the summer, could cause significant changes in the availability of water resources specially in the Mediterranean region. European countries need to encourage sustainable agriculture practices, reducing inputs, especially of water, and minimizing any negative impact on crop quantity and quality. Olive is an important crop in the Mediterranean region that has traditionally been cultivated with no irrigation and is known to attain acceptable production under dry farming. Therefore this crop will not compete for foreseen reduced water resources. However, a good quantitative knowledge must be available about effects of reduced precipitation and water availability on yield. Yield response functions, coupled with indicators of soil water availability, provide a quantitative description of the cultivar- specific behavior in relation to hydrological conditions. Yield response functions of 11 olive cultivars, typical of Mediterranean environment, were determined using experimental data (unpublished or reported in scientific literature). The yield was expressed as relative yield (Yr); the soil water availability was described by means of different indicators: relative soil water deficit (RSWD), relative evapotranspiration (RED) and transpiration deficit (RTD). Crops can respond nonlinearly to changes in their growing conditions and exhibit threshold responses, so for the yield functions of each olive cultivar both linear regression and threshold-slope models were considered to evaluate the best fit. The level of relative yield attained in rain-fed conditions was identified and defined as the acceptable yield level (Yrrainfed). The value of the indicator (RSWD, RED and RTD) corresponding to Yrrainfed was determined for each cultivar and indicated as the critical value of water availability. The error in the determination of the critical value was estimated. By means of a

  12. Geochemical proxies of North American freshwater routing during the Younger Dryas cold event.

    Science.gov (United States)

    Carlson, Anders E; Clark, Peter U; Haley, Brian A; Klinkhammer, Gary P; Simmons, Kathleen; Brook, Edward J; Meissner, Katrin J

    2007-04-17

    The Younger Dryas cold interval represents a time when much of the Northern Hemisphere cooled from approximately 12.9 to 11.5 kiloyears B.P. The cause of this event, which has long been viewed as the canonical example of abrupt climate change, was initially attributed to the routing of freshwater to the St. Lawrence River with an attendant reduction in Atlantic meridional overturning circulation. However, this mechanism has recently been questioned because current proxies and dating techniques have been unable to confirm that eastward routing with an increase in freshwater flux occurred during the Younger Dryas. Here we use new geochemical proxies (DeltaMg/Ca, U/Ca, and (87)Sr/(86)Sr) measured in planktonic foraminifera at the mouth of the St. Lawrence estuary as tracers of freshwater sources to further evaluate this question. Our proxies, combined with planktonic delta(18)O(seawater) and delta(13)C, confirm that routing of runoff from western Canada to the St. Lawrence River occurred at the start of the Younger Dryas, with an attendant increase in freshwater flux of 0.06 +/- 0.02 Sverdrup (1 Sverdrup = 10(6) m(3).s(-1)). This base discharge increase is sufficient to have reduced Atlantic meridional overturning circulation and caused the Younger Dryas cold interval. In addition, our data indicate subsequent fluctuations in the freshwater flux to the St. Lawrence River of approximately 0.06-0.12 Sverdrup, thus explaining the variability in the overturning circulation and climate during the Younger Dryas.

  13. Max-stable based evaluation of impacts of climate indices on extreme precipitation processes across the Poyang Lake basin, China

    Science.gov (United States)

    Zhang, Qiang; Xiao, Mingzhong; Singh, Vijay P.; Chen, Yongqin David

    2014-11-01

    Monthly precipitation extremes defined by monthly maximum one-day precipitation amount (Rx1day) and maximum consecutive five-day precipitation amount (Rx5day) were analyzed based on daily precipitation data covering a period of 1957 to 2010 across the Poyang Lake basin, the largest freshwater lake basin in the lower Yangtze River basin, China. Based on the max-stable, impacts of El Niño-Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Indian Ocean Dipole (IOD), Pacific Decadal Oscillation (PDO) on the annual and seasonal Rx1day and Rx5day regimes in the Poyang Lake basin were evaluated. Results indicated that annual Rx1day and Rx5day were influenced mainly by the ENSO events a year earlier and the relations between annual Rx1day and Rx5day and ENSO were statistically positive. However, influences of climate indices on the seasonal Rx1day and Rx5day are complicated when compared with the influences on annual Rx1day and Rx5day regimes. ENSO and PDO can enhance the spring Rx1day regime of the subsequent year and the same year, respectively, but IOD weakens spring Rx1day in the same year. In summer, ENSO can enhance Rx1day of the subsequent year. However, Rx1day in summer had a decreasing tendency. IOD and NAO influenced the autumn Rx1day in another way, i.e., IOD decreases autumn Rx1day of the subsequent year; while NAO enhances autumn Rx1day of the same year. Meanwhile, ENSO can amplify the summer Rx1day in terms of variability, while IOD and NAO can, respectively, influence autumn and winter Rx1day in terms of mean. Influences of climate indices on annual and seasonal Rx5day are similar to those on Rx1day. Results of this study are of great theoretical as well as practical merit in terms of evaluation of droughts and floods under the influences of climate indices.

  14. Using aridity indices to describe some climate and soil features in Eastern Europe: a Romanian case study

    Science.gov (United States)

    Paltineanu, C.; Mihailescu, I. F.; Seceleanu, I.; Dragota, C.; Vasenciuc, F.

    2007-11-01

    As a result of climatic change associated with global warming, aridity is an increasing problem in many parts of the world, including south-eastern and southern regions of Romania. This paper clarifies the concept of aridity, and discusses related concepts including indices of aridity, and their influence on some landscape and soil features including climatic water deficit (WD) and the depth to soil carbonates (DC). As used here, WD is calculated as the difference between precipitation sum (P) and the Penman-Monteith reference evapotranspiration sum (ETo-PM) over certain periods. Another three well-known aridity indices are also considered: De Martonne’s index (Iar-DM), Thornthwaite’s index (Iar-TH), the UNESCO (1979) P/ETo-PM ratio index (Iar-P/ETo-PM). WD is as high as -450 mm during the growing season in the most arid, south-eastern and southern regions of Romania, especially in the Dobrogea and Baragan areas. In other regions of Romania, including most of the plains and plateaus where agriculture is an important branch of the economy, WD reaches -100 to -300 mm during the growing season. The above aridity indices were spatially interpolated for specific periods by kriging, to generate relatively homogeneous areas. WD can also be seen as an aridity index which has the advantage of a more accurate quantification of the water supply needed for a reference crop, e.g. grass under standardised conditions, for various geographical regions. WD is significantly correlated with the other aridity indexes and with DC. This paper also examines the risk of aridity spreading, and suggests improvements to the water management system for agriculture in Romania.

  15. Non-stationary flood frequency analysis in continental Spanish rivers, using climate and reservoir indices as external covariates

    Directory of Open Access Journals (Sweden)

    J. López

    2013-08-01

    Full Text Available Recent evidences of the impact of persistent modes of regional climate variability, coupled with the intensification of human activities, have led hydrologists to study flood regime without applying the hypothesis of stationarity. In this study, a framework for flood frequency analysis is developed on the basis of a tool that enables us to address the modelling of non-stationary time series, namely, the "generalized additive models for location, scale and shape" (GAMLSS. Two approaches to non-stationary modelling in GAMLSS were applied to the annual maximum flood records of 20 continental Spanish rivers. The results of the first approach, in which the parameters of the selected distributions were modelled as a function of time only, show the presence of clear non-stationarities in the flood regime. In a second approach, the parameters of the flood distributions are modelled as functions of climate indices (Arctic Oscillation, North Atlantic Oscillation, Mediterranean Oscillation and the Western Mediterranean Oscillation and a reservoir index that is proposed in this paper. The results when incorporating external covariates in the study highlight the important role of interannual variability in low-frequency climate forcings when modelling the flood regime in continental Spanish rivers. Also, with this approach it is possible to properly introduce the impact on the flood regime of intensified reservoir regulation strategies. The inclusion of external covariates permits the use of these models as predictive tools. Finally, the application of non-stationary analysis shows that the differences between the non-stationary quantiles and their stationary equivalents may be important over long periods of time.

  16. NCA-LDAS: A Terrestrial Water Analysis System Enabling Sustained Assessment and Dissemination of National Climate Indicators

    Science.gov (United States)

    Jasinski, M. F.; Kumar, S.; Peters-Lidard, C. D.; Arsenault, K. R.; Beaudoing, H. K.; Bolten, J. D.; Borak, J.; Kempler, S.; Li, B.; Mocko, D. M.; Rodell, M.; Rui, H.; Silberstein, D. S.; Teng, W. L.; Vollmer, B.

    2016-12-01

    The National Climate Assessment - Land Data Assimilation System, or NCA-LDAS, is an integrated terrestrial water analysis system created as an end-to-end enabling tool for sustained assessment and dissemination of terrestrial hydrologic indicators in support of the NCA. The primary features are i) gridded, daily time series of over forty hydrologic variables including terrestrial water and energy balance stores, states and fluxes over the continental U.S. derived from land surface modeling with multivariate satellite data record assimilation (1979-2015), ii) estimated trends of the principal water balance components over a wide range of scales and locations, and iii) public dissemination of all NCA-LDAS model forcings, and input and output data products through dedicated NCA-LDAS and NASA GES-DISC websites. NCA-LDAS supports sustained assessment of our national terrestrial hydrologic climate for improved scientific understanding, and the adaptation and management of water resources and related energy sectors. This presentation provides an overview of the NCA-LDAS system together with an evaluation of the initial release of NCA-LDAS data products and trends using two land surface models; Noah Ver. 3.3 and Catchment Ver. Fortuna 2.5, and a listing of several available pathways for public access and visualization of NCA-LDAS background information and data products.

  17. Micropalaeontological proxies for understanding palaeoclimate

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    rise, climate change are all consequences of increased emission of green house gases. Such environmental problems are economically taxing to every economy. Thus prediction of future climates on the decadal and centennial time-scales helps... in the right management and distribution of resources. Predictive models are derived on the basis of large datasets on past climates, spanning thousands of years, i.e. well beyond the era of instrumental records which exist just for about 150 years...

  18. Analysis of the Joint Link between Extreme Temperatures, Precipitation and Climate Indices in Winter in the Three Hydroclimate Regions of Southern Quebec

    Directory of Open Access Journals (Sweden)

    Ali A. Assani

    2017-04-01

    Full Text Available We analyze the relationship between four climate variables (maximum and minimum extreme temperatures, rainfall and snowfall measured in winter (December to March at 17 stations from 1950 to 2000 in the three hydroclimate regions of southern Quebec, and six seasonal climate indices using canonical correlation analysis (CCA and the copula method. This analysis yielded these major results: (1 extreme temperatures are not correlated with the amount of winter rain or snow in southern Quebec; (2 winter seasonal climate indices show better correlations with climate variables than do fall climate indices; (3 winter extreme temperatures are best correlated (positive correlation with the Atlantic Multidecadal Oscillation (AMO in the eastern region, but show a negative correlation with the Arctic Oscillation (AO in the southwestern region; (4 the total amount of winter snow is best correlated (negative correlation with the Pacific Decadal Oscillation (PDO in the three hydroclimate regions; (5 the total amount of winter rain is best (negatively correlated with PDO in the eastern region, but shows a positive correlation with AO in the southeast region. Finally, the copula method revealed very little change in the dependence between climate indices and climate variables in the three hydroclimate regions.

  19. Arctic Sea Ice Thickness Distribution as an Indicator of Arctic Climate Change - Synthesis of Model Results and Observations

    Science.gov (United States)

    Maslowski, Wieslaw; Clement Kinney, Jaclyn; Jakacki, Jaromir; Osinski, Robert; Zwally, Jay

    2010-05-01

    The Arctic region is an integral part of the Earth's climate system through its influence on global surface energy and moisture fluxes and on atmospheric and oceanic circulation. Within the Arctic, its sea ice cover is possibly the most sensitive indicator of the polar amplified global warming and of the state of Arctic climate system as a whole. Hence changes in Arctic climate and the decline of multi-year sea ice cover have significant ramifications to the entire pan-Arctic region and beyond. Having the recorded average global surface temperature about 0.54°C (0.96°F) above the 20th Century average the decade of 2000-2009 has been the warmest of the 130-year record, with the maximum positive temperatures anomalies in the northern high latitude regions. Satellite records of the Arctic sea ice show a decreasing and accelerating trend in ice extent and concentration since the late 1979, as a result of the global warming. More importantly there is growing evidence that the Arctic sea ice thickness and volume have been decreasing at even faster rate. This means that our knowledge of the Arctic sea ice melt might be significantly biased due to the interpretation of 2-dimensional sea ice extent / concentration records only instead of ice thickness and volume. The rates of recent ice thickness and volume melt derived from our pan-Arctic coupled ice-ocean model results combined with recent remotely sensed data suggest an accelerating negative trend. This trend is robust and lends credence to the postulation that the Arctic not only might but it is likely to be ice-free during the summer in the near future. However, global climate models vary widely in their predictions of warming and the rate of Arctic ice melt, suggesting it may take anywhere from a couple of decades to more than a century to melt most of the summer sea ice cover. Also many regional models are limited in their representation of the rapid Arctic sea ice thinning and volume loss. The inability of models

  20. Appraising timing response of paleoenvironmental proxies to the Bond cycle in the western Mediterranean over the last 20 kyr

    Science.gov (United States)

    Rodrigo-Gámiz, Marta; Martínez-Ruiz, Francisca; Rodríguez-Tovar, Francisco J.; Pardo-Igúzquiza, Eulogio; Ortega-Huertas, Miguel

    2017-07-01

    The timing of climate responses to the Bond cycle is investigated in the western Mediterranean. Periodicities had been previously reported in a marine sediment record from this region spanning the last 20 kyr, and registered by diverse paleoenvironmental proxies, in particular those associated with terrigenous input, redox conditions, productivity, sea surface temperature (SST) and salinity. Further cross-spectral analyses on these time series reveal leads-lags in the 1400 year climate cycle. Considering as reference a terrigenous input proxy (the K/Al ratio), all the paleoenvironmental proxies displayed time shifts varying from ca. 700 year to ca. 350 year. SST and salinity variations show a first leaded response with the inflow of cold and less salty Atlantic waters. Followed by a time lead of 525 year, progresively arid conditions with an increase of eolian dust transport to the area, given by the Zr/Al signal, are observed. The intensification of dust transport could have triggered a latest biological response, lead by 350 year, with an increase of productivity, as suggested by the Ba/Al ratio. Lastly changes in the Mediterranean thermohaline circulation, indicated by a selected redox proxy (the U/Th ratio), are observed. These results support that the oceanic response triggered the atmospheric response to the Bond cycle in the western Mediterranean. Changes in the North Atlantic Oscillation mode and in the Inter-Tropical Convergence Zone migrations with variations in the monsoon activity or Saharan winds system, are considered as main forcing mechanisms, with a complex relationship of the involved phenomena.

  1. Measuring SIP proxy server performance

    CERN Document Server

    Subramanian, Sureshkumar V

    2013-01-01

    Internet Protocol (IP) telephony is an alternative to the traditional Public Switched Telephone Networks (PSTN), and the Session Initiation Protocol (SIP) is quickly becoming a popular signaling protocol for VoIP-based applications. SIP is a peer-to-peer multimedia signaling protocol standardized by the Internet Engineering Task Force (IETF), and it plays a vital role in providing IP telephony services through its use of the SIP Proxy Server (SPS), a software application that provides call routing services by parsing and forwarding all the incoming SIP packets in an IP telephony network.SIP Pr

  2. The death assemblage as a marker for habitat and an indicator of climate change: Georges Bank, surfclams and ocean quahogs

    Science.gov (United States)

    Powell, Eric N.; Kuykendall, Kelsey M.; Moreno, Paula

    2017-06-01

    A comprehensive dataset for the Georges Bank region is used to directly compare the distribution of the death assemblage and the living community at large spatial scales and to assess the application of the death assemblage in tracking changes in species' distributional pattern as a consequence of climate change. Focus is placed on the biomass-dominant clam species of the northwest Atlantic continental shelf: the surfclam Spisula solidissima and the ocean quahog Arctica islandica, for which extensive datasets exist on the distributions of the living population and the death assemblage. For both surfclams and ocean quahogs, the distribution of dead shells, in the main, tracked the distribution of live animals relatively closely. Thus, for both species, the presence of dead shells was a positive indicator of present, recent, or past occupation by live animals. Shell dispersion within habitat was greater for surfclams than for ocean quahogs either due to spatial time averaging, animals not living in all habitable areas all of the time, or parautochthonous redistribution of shell. The regional distribution of dead shell differed from the distribution of live animals, for both species, in a systematic way indicative of range shifts due to climate change. In each case the differential distribution was consistent with warming of the northwest Atlantic. Present-day overlap of live surfclams with live ocean quahogs was consistent with the expectation that the surfclam's range is shifting into deeper water in response to the recent warming trend. The presence of locations devoid of dead shells where live surfclams nevertheless were collected measures the recentness of this event. The presence of dead ocean quahog shells at shallower depths than live ocean quahogs offers good evidence that a range shift has occurred in the past, but prior to the initiation of routine surveys in 1980. Possibly, this range shift tracks initial colonization at the end of the Little Ice Age.

  3. Understanding Climate Change Impacts in a Cholera Endemic Megacity: Disease Trends, Hydroclimatic Indicators and Near Future-Term Projections

    Science.gov (United States)

    Akanda, A. S. S.; Hasan, M. A.; Serman, E. A.; Jutla, A.; Huq, A.; Colwell, R. R.

    2015-12-01

    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. While an endemic trend is getting stronger in the dry season, the post-monsoon season shows increased variability and is epidemic in nature. The pre-monsoon dry season is becoming the dominant cholera season of the year, followed by monsoon flood related propagation in later months of the year. Although the heavily populated and rapidly urbanizing Dhaka region has experienced noticeable shifts in pre monsoon temperature and precipitation patterns and subsequent monsoon variations, to date, there has not been any systematic study on linking the long-term disease trends with observed changes in hydroclimatic indicators. Here, we focus on the past 30-year dynamics of urban cholera prevalence in Dhaka with changes in climatic or anthropogenic forcings to develop projections for the next 30-year period. We focus on the dry and the wet season indicators individually, and develop trends of maximum rainfall intensity, lowest rainfall totals in the pre-monsoon period, number of consecutive dry days, number of wet days, and number of rainy days with greater than 500mm rainfall using a recently developed gridded data product - and compare with regional hydrology, flooding, water usage, changes in distribution systems, population growth and density in urban settlements, and frequency of natural disasters. We then use a bias correction method to develop the next 30 years projections of CMIP5 Regional Climate Model outputs and impacts on cholera prevalence using a probabilistic forecasting approach.

  4. Calibration, validation and application of foraminiferal carbonate based proxies. Reconstructing temperature, salinity and sea water Mg/Ca

    NARCIS (Netherlands)

    Wit, J.C.

    2012-01-01

    The chemistry of the calcite test of foraminifera is often relating to the environmental conditions under which they lived. These so-called proxy-relations are regularly used as a tool to reconstruct past climates. Accuracy of these proxies is, however, often limited due to uncertainties or absence

  5. Climate change indices for Greenland applied directly for other arctic regions - Enhanced and utilized climate information from one high resolution RCM downscaling for Greenland evaluated through pattern scaling and CMIP5

    Science.gov (United States)

    Olesen, M.; Christensen, J. H.; Boberg, F.

    2016-12-01

    Climate change indices for Greenland applied directly for other arctic regions - Enhanced and utilized climate information from one high resolution RCM downscaling for Greenland evaluated through pattern scaling and CMIP5Climate change affects the Greenlandic society both advantageously and disadvantageously. Changes in temperature and precipitation patterns may result in changes in a number of derived society related climate indices, such as the length of growing season or the number of annual dry days or a combination of the two - indices of substantial importance to society in a climate adaptation context.Detailed climate indices require high resolution downscaling. We have carried out a very high resolution (5 km) simulation with the regional climate model HIRHAM5, forced by the global model EC-Earth. Evaluation of RCM output is usually done with an ensemble of downscaled output with multiple RCM's and GCM's. Here we have introduced and tested a new technique; a translation of the robustness of an ensemble of GCM models from CMIP5 into the specific index from the HIRHAM5 downscaling through a correlation between absolute temperatures and its corresponding index values from the HIRHAM5 output.The procedure is basically conducted in two steps: First, the correlation between temperature and a given index for the HIRHAM5 simulation by a best fit to a second order polynomial is identified. Second, the standard deviation from the CMIP5 simulations is introduced to show the corresponding standard deviation of the index from the HIRHAM5 run. The change of specific climate indices due to global warming will then be possible to evaluate elsewhere corresponding to the change in absolute temperature.Results based on selected indices with focus on the future climate in Greenland calculated for the rcp4.5 and rcp8.5 scenarios will be presented.

  6. Constant Flux Proxies and Pleistocene Sediment Accumulation Rates on the Juan de Fuca Ridge in the Northeast Pacific

    Science.gov (United States)

    Middleton, J. L.; Mukhopadhyay, S.; Langmuir, C. H.; Costa, K.; McManus, J. F.; d'Almeida, M.; Huybers, P. J.; Winckler, G.

    2016-12-01

    Mass accumulation rates of marine sediments are often employed to constrain deposition rates of important proxies such as terrigenous dust, carbonate, and biogenic opal to quantitatively examine variations in continental aridity, atmospheric transport, and biologic productivity across changing climatic conditions. However, deposition rates that are estimated using traditional mass accumulation rates calculated from sediment core age models can be subject to bias from lateral sediment transport and limited age model resolution. Constant flux proxies, such as extraterrestrial helium-3 (3HeET) and excess thorium-230 (230ThXS), can be used to calculate vertical sediment accumulation rates that are independent of age model uncertainties and the effects of lateral sediment transport. While a short half-life limits analyses of 230ThXS to the past 500 ka, 3HeET is stable and could be used to constrain sedimentary fluxes during much of the Cenozoic. Despite the vast paleoceanographic potential of constant flux proxies, few studies have directly compared the behavior of 230ThXS and 3HeET using measurements from the same samples. Sediment grain size fractionation and local scavenging effects may differentially bias one or both proxy systems and complicate the interpretation of 230ThXS or 3HeET data. We will present a new record of vertical sediment accumulation rates spanning the past 600 ka in the Northeast Pacific constrained using analyses of both 3HeET and 230ThXS in two sediment cores from cruise AT26-19 on the Juan de Fuca Ridge. Such a record allows for intercomparison of both constant flux proxies in the mid-ocean ridge environment and examination of sedimentary behavior across multiple glacial cycles. The 230ThXS-derived accumulation rates typically range from 0.5 to 2 g cm-2 ka-1 over the past 450 ka, with periods of maximum deposition coinciding with glacial maxima. Preliminary results of samples analyzed with both 3HeET and 230ThXS indicate relative consistency

  7. Technical Note: Probabilistically constraining proxy age–depth models within a Bayesian hierarchical reconstruction model

    Directory of Open Access Journals (Sweden)

    J. P. Werner

    2015-03-01

    Full Text Available Reconstructions of the late-Holocene climate rely heavily upon proxies that are assumed to be accurately dated by layer counting, such as measurements of tree rings, ice cores, and varved lake sediments. Considerable advances could be achieved if time-uncertain proxies were able to be included within these multiproxy reconstructions, and if time uncertainties were recognized and correctly modeled for proxies commonly treated as free of age model errors. Current approaches for accounting for time uncertainty are generally limited to repeating the reconstruction using each one of an ensemble of age models, thereby inflating the final estimated uncertainty – in effect, each possible age model is given equal weighting. Uncertainties can be reduced by exploiting the inferred space–time covariance structure of the climate to re-weight the possible age models. Here, we demonstrate how Bayesian hierarchical climate reconstruction models can be augmented to account for time-uncertain proxies. Critically, although a priori all age models are given equal probability of being correct, the probabilities associated with the age models are formally updated within the Bayesian framework, thereby reducing uncertainties. Numerical experiments show that updating the age model probabilities decreases uncertainty in the resulting reconstructions, as compared with the current de facto standard of sampling over all age models, provided there is sufficient information from other data sources in the spatial region of the time-uncertain proxy. This approach can readily be generalized to non-layer-counted proxies, such as those derived from marine sediments.

  8. Framework for Probabilistic Projections of Energy-Relevant Streamflow Indicators under Climate Change Scenarios for the U.S.

    Energy Technology Data Exchange (ETDEWEB)

    Wagener, Thorsten [Univ. of Bristol (United Kingdom); Mann, Michael [Pennsylvania State Univ., State College, PA (United States); Crane, Robert [Pennsylvania State Univ., State College, PA (United States)

    2014-04-29

    This project focuses on uncertainty in streamflow forecasting under climate change conditions. The objective is to develop easy to use methodologies that can be applied across a range of river basins to estimate changes in water availability for realistic projections of climate change. There are three major components to the project: Empirical downscaling of regional climate change projections from a range of Global Climate Models; Developing a methodology to use present day information on the climate controls on the parameterizations in streamflow models to adjust the parameterizations under future climate conditions (a trading-space-for-time approach); and Demonstrating a bottom-up approach to establishing streamflow vulnerabilities to climate change. The results reinforce the need for downscaling of climate data for regional applications, and further demonstrates the challenges of using raw GCM data to make local projections. In addition, it reinforces the need to make projections across a range of global climate models. The project demonstrates the potential for improving streamflow forecasts by using model parameters that are adjusted for future climate conditions, but suggests that even with improved streamflow models and reduced climate uncertainty through the use of downscaled data, there is still large uncertainty is the streamflow projections. The most useful output from the project is the bottom-up vulnerability driven approach to examining possible climate and land use change impacts on streamflow. Here, we demonstrate an inexpensive and easy to apply methodology that uses Classification and Regression Trees (CART) to define the climate and environmental parameters space that can produce vulnerabilities in the system, and then feeds in the downscaled projections to determine the probability top transitioning to a vulnerable sate. Vulnerabilities, in this case, are defined by the end user.

  9. Novel Quantum Proxy Signature without Entanglement

    Science.gov (United States)

    Xu, Guang-bao

    2015-08-01

    Proxy signature is an important research topic in classic cryptography since it has many application occasions in our real life. But only a few quantum proxy signature schemes have been proposed up to now. In this paper, we propose a quantum proxy signature scheme, which is designed based on quantum one-time pad. Our scheme can be realized easily since it only uses single-particle states. Security analysis shows that it is secure and meets all the properties of a proxy signature, such as verifiability, distinguishability, unforgeability and undeniability.

  10. Skilled Health Personnel Attended Delivery as a Proxy Indicator for ...

    African Journals Online (AJOL)

    BACKGROUND: Several demographic and health surveys in Africa have shown the high prevalence of home delivery, but little is known how strongly skilled person unattended deliveries are associated with maternal and perinatal mortality. The aim of this review was to assess the gross correlation of maternal mortality ...

  11. Using global Climate Impact Indicators to assess water resource availability in a Mediterranean mountain catchment: the Sierra Nevada study case (Spain) in the SWICCA platform

    Science.gov (United States)

    José Pérez-Palazón, María; Pimentel, Rafael; Sáenz de Rodrigáñez, Marta; Gulliver, Zacarias; José Polo, María

    2017-04-01

    Climate services provide water resource managements and users with science-based information on the likely impacts associated to the future climate scenarios. Mountainous areas are especially vulnerable to climate variations due to the expected changes in the snow regime, among others; in Mediterranean regions, this shift involves significant effects on the river flow regime and water resource availability and management. The Guadalfeo River Basin is a 1345 km2 mountainous, coastal catchment in southern Spain, ranging from the Mediterranean Sea coastline to the Sierra Nevada mountains to the north (up to 3450 m a.s.l.) within a 40-km distance. The climate variability adds complexity to this abrupt topography and heterogeneous area. The uncertainty associated to snow occurrence and persistence for the next decades poses a challenge for the current and future water resource uses in the area. The development of easy-to-use local climate indicators and derived decision-making variables is key to assess and face the economic impact of the potential changes. The SWICCA (Service for Water Indicators in Climate Change Adaptation) Platform (http://swicca.climate.copernicus.eu/) has been developed under the Copernicus Climate Change Service (C3S) and provides global climate and hydrology indicators on a Pan-European scale. Different case studies are included to assess the platform development and contents, and analyse the indicators' performance from a proof-of-concept approach that includes end-users feedbacks. The Guadalfeo River Basin is one of these case studies. This work presents the work developed so far to analyse and use the SWICCA Climate Impact Indicators (CIIs) related to river flow in this mountainous area, and the first set of local indicators specifically designed to assess selected end-users on the potential impact associated to different climate scenarios. Different CIIs were extracted from the SWICCA interface and tested against the local information

  12. Investigating and Modelling Effects of Climatically and Hydrologically Indicators on the Urmia Lake Coastline Changes Using Time Series Analysis

    Science.gov (United States)

    Ahmadijamal, M.; Hasanlou, M.

    2017-09-01

    Study of hydrological parameters of lakes and examine the variation of water level to operate management on water resources are important. The purpose of this study is to investigate and model the Urmia Lake water level changes due to changes in climatically and hydrological indicators that affects in the process of level variation and area of this lake. For this purpose, Landsat satellite images, hydrological data, the daily precipitation, the daily surface evaporation and the daily discharge in total of the lake basin during the period of 2010-2016 have been used. Based on time-series analysis that is conducted on individual data independently with same procedure, to model variation of Urmia Lake level, we used polynomial regression technique and combined polynomial with periodic behavior. In the first scenario, we fit a multivariate linear polynomial to our datasets and determining RMSE, NRSME and R² value. We found that fourth degree polynomial can better fit to our datasets with lowest RMSE value about 9 cm. In the second scenario, we combine polynomial with periodic behavior for modeling. The second scenario has superiority comparing to the first one, by RMSE value about 3 cm.

  13. Psychosocial safety climate as a lead indicator of workplace bullying and harassment, job resources, psychological health and employee engagement.

    Science.gov (United States)

    Law, Rebecca; Dollard, Maureen F; Tuckey, Michelle R; Dormann, Christian

    2011-09-01

    Psychosocial safety climate (PSC) is defined as shared perceptions of organizational policies, practices and procedures for the protection of worker psychological health and safety, that stem largely from management practices. PSC theory extends the Job Demands-Resources (JD-R) framework and proposes that organizational level PSC determines work conditions and subsequently, psychological health problems and work engagement. Our sample was derived from the Australian Workplace Barometer project and comprised 30 organizations, and 220 employees. As expected, hierarchical linear modeling showed that organizational PSC was negatively associated with workplace bullying and harassment (demands) and in turn psychological health problems (health impairment path). PSC was also positively associated with work rewards (resources) and in turn work engagement (motivational path). Accordingly, we found that PSC triggered both the health impairment and motivational pathways, thus justifying extending the JD-R model in a multilevel way. Further we found that PSC, as an organization-based resource, moderated the positive relationship between bullying/harassment and psychological health problems, and the negative relationship between bullying/harassment and engagement. The findings provide evidence for a multilevel model of PSC as a lead indicator of workplace psychosocial hazards (high demands, low resources), psychological health and employee engagement, and as a potential moderator of psychosocial hazard effects. PSC is therefore an efficient target for primary and secondary intervention. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. WOOD CELLULAR DENDROCLIMATOLOGY: TESTING NEW PROXIES IN GREAT BASIN BRISTLECONE PINE

    Directory of Open Access Journals (Sweden)

    Emanuele Ziaco

    2016-10-01

    Full Text Available Dendroclimatic proxies can be generated from the analysis of wood cellular structures, allowing for a more complete understanding of the physiological mechanisms that control the climatic response of tree species. Century-long (1870-2013 time series of anatomical parameters were developed for Great Basin bristlecone pine (Pinus longaeva D.K. Bailey by capturing strongly contrasted microscopic images through a Confocal Laser Scanning Microscope. Environmental information embedded in wood anatomical series was analyzed in comparison with ring-width series using measures of empirical signal strength. Response functions were calculated against monthly climatic variables to evaluate climate sensitivity of cellular features (e.g. lumen area; lumen diameter for the period 1950-2013. Calibration-verification tests were used to determine the potential to generate long climate reconstructions from these anatomical proxies. A total of eight tree-ring parameters (two ring-width and six chronologies of xylem anatomical parameters were analyzed. Synchronous variability among samples varied among tree-ring parameters, usually decreasing from ring width to anatomical features. Cellular parameters linked to plant hydraulic performance (e.g. tracheid lumen area and radial lumen diameter showed empirical signal strength similar to ring-width series, while noise was predominant in chronologies of lumen tangential width and cell-wall thickness. Climatic signals were different between anatomical and ring-width chronologies, revealing a positive and temporally stable correlation of tracheid size (i.e. lumen and cell diameter with monthly (i.e. March and seasonal precipitation. In particular, tracheid lumen diameter emerged as a reliable moisture indicator and was then used to reconstruct total March-August precipitation from 1870 to 2013. Wood anatomy holds great potential to refine and expand dendroclimatic records by allowing estimates of plant physiological

  15. Clay Mineralogy and Crystallinity as a Climatic Indicator: Evidence for Both Cold and Temperate Conditions on Early Mars

    Science.gov (United States)

    Horgan, B.; Rutledge, A.; Rampe, E. B.

    2015-01-01

    Surface weathering on Earth is driven by precipitation (rain/snow melt). Here we summarize the influence of climate on minerals produced during surface weathering, based on terrestrial literature and our new laboratory analyses of weathering products from glacial analog sites. By comparison to minerals identified in likely surface environments on Mars, we evaluate the implications for early martian climate.

  16. Developing a reduced-form ensemble of climate change scenarios for Europe and its application to selected impact indicators

    Czech Academy of Sciences Publication Activity Database

    Dubrovský, Martin; Trnka, Miroslav; Holman, I. P.; Svobodová, Eva; Harrison, P. A.

    2015-01-01

    Roč. 128, 3-4 (2015), s. 169-186 ISSN 0165-0009 R&D Projects: GA MŠk(CZ) EE2.3.20.0248 Institutional support: RVO:67179843 Keywords : adaptation * design * climate change * Europe * global climate models Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 3.344, year: 2015

  17. 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

  18. A long-term multi-proxy record of varved sediments highlights climate-induced mixing-regime shift in a large hard-water lake ~5000 years ago

    Directory of Open Access Journals (Sweden)

    Walter Finsinger

    2014-06-01

    Full Text Available The long-term terrestrial and aquatic ecosystem dynamics spanning between approximately 6200 and 4800 cal BP were investigated using pollen, diatoms, pigments, charcoal, and geochemistry from varved sediments collected in a large stratified perialpine lake, Lago Grande di Avigliana, in the Italian Alps. Marked changes were detected in diatom and pigment assemblages and in sediment composition at ~4900 cal BP. Organic matter rapidly increased and diatom assemblages shifted from oligotrophic to oligo-mesotrophic planktonic assemblages suggesting that nutrients increased at that time. Because land cover, erosion, and fire frequency did not change significantly, external nutrient sources were possibly not essential in controlling the lake-ecosystem dynamics. This is also supported by redundancy analysis, which showed that variables explaining significant amounts of variance in the diatom data were not the ones related to changes in the catchment. Instead, the broad coincidence between the phytoplankton dynamics and rising lake-levels, cooler temperatures, and stronger spring winds in the northern Mediterranean borderlands possibly points to the effects of climate change on the nutrient recycling in the lake by means of the control that climate can exert on mixing depth. We hypothesize that the increased P-release rates and higher organic-matter accumulation rates, proceeded by enhanced precipitation of iron sulphides, were possibly caused by deeper and stronger mixing leading to enhanced input of nutrients from the anoxic hypolimnion into the epilimnion. Although we cannot completely rule out the influence of minor land-cover changes due to human activities, it may be hypothesized that climate-induced cumulative effects related to mixing regime and P-recycling from sediments influenced the aquatic-ecosystem dynamics.

  19. Calcium Nodules as a Proxy for Quaternary Paleoclimate Change on China’s Loess Plateau

    Science.gov (United States)

    He, Wenming; He, Hongming; Zhu, Mingyong

    2015-01-01

    Different proxies have been used to investigate Quaternary paleoclimate change. Here, we used weathering of calcium nodules in paleosols on China’s Loess Plateau as a proxy for Quaternary paleoclimate changes to provide an alternative indicator of these changes. Paleosol and carbonate nodules were collected from Luochuan and Lantian counties in Shaanxi Province, China. We found that this approach allowed quantitative reconstruction of temperature, rainfall, soil mineral composition, and the effects of weathering and leaching. The changes in carbonate content in the loess and paleosol sequences were controlled by alternating dry and wet climatic conditions. Nodule formation conditions were directly affected by the leaching and migration of elements. The loess and paleosol sequences developed calcium nodules, and their formation was closely related to the rainfall and leaching characteristics of the paleoclimate. The paleoclimate and soil minerals affected the vegetation types and directly influenced changes in the soil. During formation of the calcium nodules, the surface vegetation evolved slowly, and the number of species and quantity of vegetation both decreased. PMID:26633304

  20. Calcium Nodules as a Proxy for Quaternary Paleoclimate Change on China's Loess Plateau.

    Science.gov (United States)

    He, Wenming; He, Hongming; Zhu, Mingyong

    2015-01-01

    Different proxies have been used to investigate Quaternary paleoclimate change. Here, we used weathering of calcium nodules in paleosols on China's Loess Plateau as a proxy for Quaternary paleoclimate changes to provide an alternative indicator of these changes. Paleosol and carbonate nodules were collected from Luochuan and Lantian counties in Shaanxi Province, China. We found that this approach allowed quantitative reconstruction of temperature, rainfall, soil mineral composition, and the effects of weathering and leaching. The changes in carbonate content in the loess and paleosol sequences were controlled by alternating dry and wet climatic conditions. Nodule formation conditions were directly affected by the leaching and migration of elements. The loess and paleosol sequences developed calcium nodules, and their formation was closely related to the rainfall and leaching characteristics of the paleoclimate. The paleoclimate and soil minerals affected the vegetation types and directly influenced changes in the soil. During formation of the calcium nodules, the surface vegetation evolved slowly, and the number of species and quantity of vegetation both decreased.

  1. Calcium Nodules as a Proxy for Quaternary Paleoclimate Change on China's Loess Plateau.

    Directory of Open Access Journals (Sweden)

    Wenming He

    Full Text Available Different proxies have been used to investigate Quaternary paleoclimate change. Here, we used weathering of calcium nodules in paleosols on China's Loess Plateau as a proxy for Quaternary paleoclimate changes to provide an alternative indicator of these changes. Paleosol and carbonate nodules were collected from Luochuan and Lantian counties in Shaanxi Province, China. We found that this approach allowed quantitative reconstruction of temperature, rainfall, soil mineral composition, and the effects of weathering and leaching. The changes in carbonate content in the loess and paleosol sequences were controlled by alternating dry and wet climatic conditions. Nodule formation conditions were directly affected by the leaching and migration of elements. The loess and paleosol sequences developed calcium nodules, and their formation was closely related to the rainfall and leaching characteristics of the paleoclimate. The paleoclimate and soil minerals affected the vegetation types and directly influenced changes in the soil. During formation of the calcium nodules, the surface vegetation evolved slowly, and the number of species and quantity of vegetation both decreased.

  2. Munchausen Syndrome by Proxy: Identification and Intervention

    Science.gov (United States)

    Walk, Alexandra; Davies, Susan C.

    2010-01-01

    This article discusses the Munchausen syndrome by proxy (MSBP), also known as "factitious disorder by proxy" (FDBP) and fabricated and/or induced illness, which is a mental illness in which a person lies about the physical or mental well-being of a person he/she is responsible for. Most often the dynamic transpires between a mother and her child.…

  3. Comfort with proxy consent to research involving decisionally impaired older adults: do type of proxy and risk-benefit profile matter?

    Science.gov (United States)

    Dubois, Marie-France; Bravo, Gina; Graham, Janice; Wildeman, Sheila; Cohen, Carole; Painter, Karen; Bellemare, Suzanne

    2011-11-01

    Dementia research often requires the participation of people with dementia. Obtaining informed consent is problematic when potential participants lack the capacity to provide it. We investigated comfort with proxy consent to research involving older adults deemed incapable of this decision, and examined if comfort varies with the type of proxy and the study's risk-benefit profile. We surveyed random samples of five relevant groups (older adults, informal caregivers, physicians, researchers in aging, and Research Ethics Board members) from four Canadian provinces. Respondents were presented with scenarios involving four types of proxies (non-assigned, designated in a healthcare advance directive with or without instructions specific to research participation, and court-appointed). Given a series of risk-benefit profiles, respondents indicated whether they were comfortable with proxy consent to research for each scenario. Two percent of the respondents felt proxy consent should never be allowed. In all groups, comfort depended far more on the risk-benefit profile associated with the research scenario than with type of proxy. For research involving little or no risk and potential personal benefits, over 90% of the respondents felt comfortable with substitute consent by a designated or court-appointed proxy while 80% were at ease with a non-assigned proxy. For studies involving serious risks with potentially greater personal benefits, older adults and informal caregivers were less comfortable with proxy consent. A large majority of Canadians are comfortable with proxy consent for low-risk research. Further work is needed to establish what kinds of research are considered to be low risk.

  4. Tracking fluctuations in the intensity of the eastern tropical north Pacific oxygen minimum zone using a multi-proxy approach

    Science.gov (United States)

    Tems, C.

    2015-12-01

    Naturally occurring oxygen minimum zones (OMZs) are permanent midwater features that are associated with highly productive regions of the ocean, key microbial mediated biogeochemical cycling, and the deposition of organic rich sediments. The intensity of OMZs varies on glacial to interglacial time scales, indicating a relationship between the climate system and the expanse of OMZs, however, high-resolution studies tracking the fluctuations of OMZs on a near annual basis are lacking. In the Gulf of California (Pescadero Slope), the eastern tropical north Pacific OMZ impinges on basin slopes depositing laminated, hemipelagic sediments that record useful proxies of OMZ fluctuations. In an OMZ, low O2 content promotes water column denitrification, imparting an elevated 15N/14N isotopic signature on the residual nitrate in the water column. The elevated 15NO3- is upwelled and incorporated into particulate organic mater (POM) during primary production. The exported POM δ15Nsed then reflects the intensity of the regional OMZ at the time it was deposited. The Pescadero Slope record shows distinct temporal fluctuations in the δ15Nsed with decadal to multi-decadal and centennial cyclicity over the past 1200 years. The record reveals that the OMZ contracts during warmer climatic periods, including the Medieval Climate Optimum and the Industrial Revolution, and expands during cooler climates, specifically the Little Ice Age. The local mechanisms that are influencing fluctuations in the OMZ are investigated through an analysis of productivity proxies, including weight percent organic carbon and weight percent biogenic silica, and indicate OMZ expansion during periods of high productivity. Local productivity is driven by the intensity in the easterly trade winds in the Pacific, and thus the relationship between regional trade wind intensity and fluctuations in the intensity of the OMZ over the past 160 years will be discussed.

  5. Altitudinal effect of soil glycerol dialkyl glycerol tetraether on the southeastern Tibetan Plateau: availability as a paleoaltitude proxy

    Science.gov (United States)

    Bai, Y.

    2016-12-01

    Tibetan Plateau uplift was an important dynamic factor in global climate change during the Late Cenozoic, which in turn strongly influenced the development of the Asian monsoon system. Recently, the distribution of branched GDGTs (brGDGTs) has been proposed as a new paleoaltitude proxy. However, the suitability and reliability of the MBT'/CBT ratio (i.e., the ratio between the methylation and cyclization indices of branched tetraethers) as a paleoaltitude proxy has not been fully verified. In this study, we present the distribution of bacterial brGDGTs in 88 soils along two vapor transport pathways (comprising four transects) running across the southeastern Tibetan Plateau (SE TP), i.e., the South Himalayan Transect (SH; altitude range 1.66-5.05 km* above sea level (asl), representing the Southern Himalayan airmass), and the Bayi-Lhasa (BL; altitude 3.05-4.97 km asl), Bomi-Bayi (BB; altitude 2.030-4.555 km asl) and Zayu-Bomi (ZB; altitude 1.468-4.8 km asl) transects, together representing the Brahmaputra-Yarlung Zangbo River Valley airmass, to verify the suitability, and examine the reliability, of the MBT'/CBT ratio as a paleoaltitude proxy. MBT'/CBT-derived temperatures and MBT' exhibit a strong relation with altitude (R2=0.84 and R2=0.70, respectively) for all of the sampled localities with neutral and acidic soils, compared to the relation between n-alkane δDwax and altitude (R2=0.78; n=76). These findings have significant implications for using neutral and acidic sediments in paleoaltitude reconstructions. We found that alkaline soils with pH values >7.0 had lower MBT' and MBT'/CBT-derived temperatures, and that the brGDGTs' proxies were greatly optimized, based on separating 6-methyl brGDGTs.

  6. Modification of input datasets for the Ensemble Streamflow Prediction based on large scale climatic indices and weather generator

    Czech Academy of Sciences Publication Activity Database

    Šípek, Václav; Daňhelka, J.

    2015-01-01

    Roč. 528, September (2015), s. 720-733 ISSN 0022-1694 Institutional support: RVO:67985874 Keywords : seasonal forecasting * ESP * large-scale climate * weather generator Subject RIV: DA - Hydrology ; Limnology Impact factor: 3.043, year: 2015

  7. NDVI‐indicated long‐term vegetation dynamics in Mongolia and their response to climate change at biome scale

    National Research Council Canada - National Science Library

    Bao, Gang; Bao, Yuhai; Sanjjava, Amarjargal; Qin, Zhihao; Zhou, Yi; Xu, Guang

    2015-01-01

    ...), and temperature and precipitation data derived from 60 meteorological stations, this study has thoroughly examined vegetation dynamics in Mongolia and their responses to regional climate change at biome scale...

  8. Fossil pigments as indicators of phototrophic response to salinity and climatic change in lakes of Western Canada

    Energy Technology Data Exchange (ETDEWEB)

    Vinebrooke, R. D.; Hall, R. I.; Leavitt, R. [Regina Univ., SK (Canada). Dept. of Biology; Cumming, B. F. [Queen`s Univ., Kingston, ON (Canada). Paleoecological Environmental Assessment and Research Lab

    1998-03-01

    Changes in fossil pigments among 111 saline lakes in British Columbia were quantified and past changes in phototrophic communities in three closed-basin prairie lakes (Antelope Lake, Kenosee Lake and Clearwater Lake) were reconstructed. Using redundancy analysis, it was found that pigment concentrations were greatest in deep stratified lakes but were unaffected by ion concentrations, pH or conductivity. Algal standing crop was correlated only with fossil measures of total algal abundance, however, relative abundance of fossil carotenoids varied with lake chemistry. Increase in salinity caused fucoxanthin to be replaced by lutein-zeaxanthin and diatoxanthin, while alloxanthin and myxoxanthophyll were most commonly found in lakes with low calcium and high dissolved organic carbon content. Post-depositional degradation did not appear to alter the relation between pigment abundance and environmental characteristics. Considered as a whole, these results suggest that in saline lakes, fossil pigments are paleoecological proxies for phototrophic community change. 43 refs., 8 figs.

  9. Long-term forest resilience to climate change indicated by mortality, regeneration, and growth in semiarid southern Siberia.

    Science.gov (United States)

    Xu, Chongyang; Liu, Hongyan; Anenkhonov, Oleg A; Korolyuk, Andrey Yu; Sandanov, Denis V; Balsanova, Larisa D; Naidanov, Bulat B; Wu, Xiuchen

    2017-06-01

    Several studies have documented that regional climate warming and the resulting increase in drought stress have triggered increased tree mortality in semiarid forests with unavoidable impacts on regional and global carbon sequestration. Although climate warming is projected to continue into the future, studies examining long-term resilience of semiarid forests against climate change are limited. In this study, long-term forest resilience was defined as the capacity of forest recruitment to compensate for losses from mortality. We observed an obvious change in long-term forest resilience along a local aridity gradient by reconstructing tree growth trend and disturbance history and investigating postdisturbance regeneration in semiarid forests in southern Siberia. In our study, with increased severity of local aridity, forests became vulnerable to drought stress, and regeneration first accelerated and then ceased. Radial growth of trees during 1900-2012 was also relatively stable on the moderately arid site. Furthermore, we found that smaller forest patches always have relatively weaker resilience under the same climatic conditions. Our results imply a relatively higher resilience in arid timberline forest patches than in continuous forests; however, further climate warming and increased drought could possibly cause the disappearance of small forest patches around the arid tree line. This study sheds light on climate change adaptation and provides insight into managing vulnerable semiarid forests. © 2016 John Wiley & Sons Ltd.

  10. Heinrich event 4 characterized by terrestrial proxies in southwestern Europe

    Directory of Open Access Journals (Sweden)

    J. M. López-García

    2013-05-01

    Full Text Available Heinrich event 4 (H4 is well documented in the North Atlantic Ocean as a cooling event that occurred between 39 and 40 Ka. Deep-sea cores around the Iberian Peninsula coastline have been analysed to characterize the H4 event, but there are no data on the terrestrial response to this event. Here we present for the first time an analysis of terrestrial proxies for characterizing the H4 event, using the small-vertebrate assemblage (comprising small mammals, squamates and amphibians from Terrassa Riera dels Canyars, an archaeo-palaeontological deposit located on the seaboard of the northeastern Iberian Peninsula. This assemblage shows that the H4 event is characterized in northeastern Iberia by harsher and drier terrestrial conditions than today. Our results were compared with other proxies such as pollen, charcoal, phytolith, avifauna and large-mammal data available for this site, as well as with the general H4 event fluctuations and with other sites where H4 and the previous and subsequent Heinrich events (H5 and H3 have been detected in the Mediterranean and Atlantic regions of the Iberian Peninsula. We conclude that the terrestrial proxies follow the same patterns as the climatic and environmental conditions detected by the deep-sea cores at the Iberian margins.

  11. EXTREME WINTERS IN XX–XXI CENTURIES AS INDICATORS OF SNOWINESS AND AVALANCHE HAZARD IN THE PAST AND EXPECTED CLIMATE CHANGE CONDITIONS

    Directory of Open Access Journals (Sweden)

    A. D. Oleynikov

    2012-01-01

    Full Text Available Currently, due to the global climate change and increasing frequency of weather events focus is on prediction of climate extremes. Large-scale meteorological anomalies can cause long-term paralysis of social and economic infrastructure of the major mountain regions and even individual states. In winter periods, these anomalies are associated with prolonged heavy snowfalls and associated with them catastrophic avalanches which cause significant social and economic damage. The climate system maintains a certain momentum during periods of adjustment and transition to other conditions in the ratio of heat and moisture and contains a climate «signal» of the climates of the past and the future. In our view seasonal and yearly extremes perform the role of these indicators, study of which enables for a deeper understanding and appreciation of the real situation of the climate periods related to the modern ones. The paper provides an overview of the criteria for selection of extreme winters. Identification of extremely cold winters during the period of instrumental observation and assessment of their snowiness and avalanche activity done for the Elbrus region, which is a model site for study of the avalanche regime in the Central Caucasus. The studies aim to identify the extreme winters in the Greater Caucasus, assess their frequency of occurrence, characterize the scale and intensity of the avalanche formation. The data obtained can be used to identify winter-analogues in the reconstruction and long-term forecast of avalanches. 

  12. Beyond Standardized Test Scores: An Examination of Leadership and Climate as Leading Indicators of Future Success in the Transformation of Turnaround Schools

    Science.gov (United States)

    May, Judy Jackson; Sanders, Eugene T. W.

    2013-01-01

    Districts throughout the nation are engaged in comprehensive transformation to "turn around" low performing schools. Standardized test scores are used to gauge student achievement; however, academic gains may lag behind leading indicators such as improved school climate and effective leadership. This study examines 16 underperforming…

  13. A quantitative assessment of the contributions of climatic indicators to changes in nutrients and oxygen levels in a shallow reservoir in China

    Science.gov (United States)

    Zhang, Chen; Zhang, Wenna; Liu, Hanan; Gao, Xueping; Huang, Yixuan

    2017-06-01

    Climate change has an indirect effect on water quality in freshwater ecosystems, but it is difficult to assess the contribution of climate change to the complex system. This study explored to what extent climatic indicators (air temperature, wind speed, and rainfall) influence nutrients and oxygen levels in a shallow reservoir, Yuqiao Reservoir, China. The study comprises three parts—describing the temporal trends of climatic indicators and water quality parameters during the period 1992-2011, analyzing the potential impacts of climate on water quality, and finally developing a quantitative assessment to evaluate how climatic factors govern nutrient levels in the reservoir. Our analyses showed that the reservoir experienced substantial cold periods (1992-2001) followed by a warm period (2002-2011). The results showed that increasing air temperature in spring, autumn, and winter and increasing annual wind speed decrease total phosphorus (TP) concentration in the reservoir in spring, summer, and winter. According to the quantitative assessment, the increase in air temperature in spring and winter had a larger contribution to the decrease in TP concentration (47.2 and 64.1%), compared with the influence from decreased wind speed and rainfall. The field data suggest that nutrients decline due to enhanced uptake by macrophytes in years when spring was warmer and the macrophytes started to grow earlier in the season. The increasing wind speed and air temperature in spring also significantly contribute to the increase in dissolved oxygen concentration. This study helps managers to foresee how potential future climate change might influence water quality in similar lake ecosystems.

  14. Relating climatic attributes and water resources allocation: A study using surface water supply and soil moisture indices in the Snake River basin, Idaho

    Science.gov (United States)

    Hoekema, David J.; Sridhar, Venkataramana

    2011-07-01

    Climate change forced by anthropogenic activities has been ongoing since at least the beginning of the industrial revolution. Part of the recent warming in the western United States has been attributed to anthropogenic climate change. This research seeks to answer the basic question of how declining streamflow, increasing temperatures, and fluctuation in precipitation have impacted water resource allocation in the Snake River Plain over the past 35 years (1971-2005). Understanding how changes in climatic attributes have historically impacted water allocation should help water managers better understand how projected climate change may influence allocation. Annual and monthly diversion trends from 62 locations in the Snake River Plain were compared to temperature and precipitation trends at 10 climate stations across the basin. We found a strong trend of declining annual surface water diversions across the study area. Of the 62 diversion points examined, 45 have highly significant decreasing annual diversion trends, while an additional 8 have significant decreasing trends. Despite the annual decline in surface water diversions, April diversions have increased at more than half of the diversion points, with 15 locations showing highly significant trends and an additional 17 showing significant increasing diversion trends. A comparison of diversions to the Surface Water Supply Index indicates that the decline in midseason and late season diversions is mostly caused by decreasing supply in the study period, while a comparison of diversions to Palmer's Z index and the Standardized Precipitation Index indicates that early season diversions are highly correlated to early season moisture anomalies.

  15. Ichthyoplankton Time Series: A Potential Ocean Observing Network to Provide Indicators of Climate Impacts on Fish Communities along the West Coast of North America

    Science.gov (United States)

    Koslow, J. A.; Brodeur, R.; Duffy-Anderson, J. T.; Perry, I.; jimenez Rosenberg, S.; Aceves, G.

    2016-02-01

    Ichthyoplankton time series available from the Bering Sea, Gulf of Alaska and California Current (Oregon to Baja California) provide a potential ocean observing network to assess climate impacts on fish communities along the west coast of North America. Larval fish abundance reflects spawning stock biomass, so these data sets provide indicators of the status of a broad range of exploited and unexploited fish populations. Analyses to date have focused on individual time series, which generally exhibit significant change in relation to climate. Off California, a suite of 24 midwater fish taxa have declined > 60%, correlated with declining midwater oxygen concentrations, and overall larval fish abundance has declined 72% since 1969, a trend based on the decline of predominantly cool-water affinity taxa in response to warming ocean temperatures. Off Oregon, there were dramatic differences in community structure and abundance of larval fishes between warm and cool ocean conditions. Midwater deoxygenation and warming sea surface temperature trends are predicted to continue as a result of global climate change. US, Canadian, and Mexican fishery scientists are now collaborating in a virtual ocean observing network to synthesize available ichthyoplankton time series and compare patterns of change in relation to climate. This will provide regional indicators of populations and groups of taxa sensitive to warming, deoxygenation and potentially other stressors, establish the relevant scales of coherence among sub-regions and across Large Marine Ecosystems, and provide the basis for predicting future climate change impacts on these ecosystems.

  16. Machine Learning Approaches to Drought Monitoring and Assessment through Blending of Multi-sensor Indices for Different Climate Regions

    Science.gov (United States)

    Park, Seonyoung; Im, Jungho; Jang, Eunna; Yoon, Hyunjin; Rhee, Jinyoung

    2014-05-01

    Drought causes a water shortage problem which threats human life as well as affects agricultural resources. Unlike other natural disasters such as floods, earthquakes, and landslides, drought is a slow-moving disaster, which is hard to accurately quantify spatio-temporal starting and ending points of the process. It is also difficult to estimate the damage from drought, because such damage combines social, economic, and environmental components in multi-temporal scales. There are many definitions of drought considering its type, temporal scales and regions. Drought has been actively monitored all over the world using in situ meteorological and climate measurements and satellite remote sensing measurements. There are many drought indices that use in situ measurements collected at weather stations, including z-score, Standard Precipitation Index (SPI), and Palmer Drought Severity Index (PDSI). However, these indices are point-based and limited in covering vast areas to show spatial distribution of drought. Since spatial interpolation is required to estimate spatial distribution of drought from in-situ measurements, uncertainty of drought estimation typically increases where in situ data are limited. Drought monitoring and assessment using satellite products provide an effective way as satellite data cover vast areas at high temporal resolution (e.g., daily). Most of remote sensing-based drought studies have focused on arid regions because satellite products usually well respond to the surface condition of short-term drought in arid regions. While drought often occurs in humid regions, satellite-based drought monitoring of such regions needs further investigation. In this study, remote sensing-based drought monitoring and assessment were evaluated for both arid and humid regions in the United States between 2000 and 2012 focusing on metrological and agricultural drought. Since there is no single indicator that represents complexity and diversity of drought, a total 11

  17. New proxy replacement algorithm for multimedia streaming

    Science.gov (United States)

    Wong, Hau Ling; Lo, Kwok-Tung

    2001-11-01

    Proxy servers play an important role in between servers and clients in various multimedia systems on the Internet. Since proxy servers do not have an infinite-capacity cache for keeping all the continuous media data, the challenge for the replacement policy is to determine which streams should be cached or removed from the proxy server. In this paper, a new proxy replacement algorithm, named the Least Popular Used (LPU) caching algorithm, is proposed for layered encoded multimedia streams in the Internet. The LPU method takes both the short-term and long-term popularity of the video into account in determining the replacement policy. Simulation evaluation shows that our proposed scheme achieves better results than some existing methods in term of the cache efficiency and replacement frequency under both static and dynamic access environments.

  18. 78 FR 70987 - Proxy Advisory Firm Roundtable

    Science.gov (United States)

    2013-11-27

    ... of proxy advisory firm use by investment advisers and institutional investors and potential changes... Special Counsel, Division of Investment Management, at 202-551-6700, or Raymond Be, Special Counsel...

  19. A serial Munchausen syndrome by proxy

    National Research Council Canada - National Science Library

    Esra Unal; Volkan Unal; Ali Gul; Mustafa Celtek; Behzat Diken; Ibrahim Balcioglu

    2017-01-01

    Munchausen syndrome by proxy (MSBP) is a form of child abuse that describes children whose parents or caregivers invent illness stories and substantiate the stories by fabricating false physical signs...

  20. Seizures and Munchausen Syndrome by Proxy

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2002-05-01

    Full Text Available The prevalence, morbidity and mortality, diagnosis and management of cases of fabricated seizures and child abuse (Munchausen syndrome by proxy (MSbp are assessed by pediatricians at the University of Wales College of Medicine, Cardiff, UK.

  1. Munchausen Syndrome by Proxy: A Clinical Vignette

    Science.gov (United States)

    Zylstra, Robert G.; Miller, Karl E.; Stephens, Walter E.

    2000-01-01

    Munchausen syndrome by proxy is the act of one person fabricating or inducing an illness in another to meet his or her own emotional needs through the treatment process. The diagnosis is poorly understood and controversial. We report here the case of a 6-year-old boy who presented with possible pneumonia, nausea, vomiting, and diarrhea and whose mother was suspected of Munchausen syndrome by proxy. PMID:15014581

  2. PENGELOLAAN JARINGAN INTERNET DENGAN PROXY WINGATE

    Directory of Open Access Journals (Sweden)

    Titin Winarti

    2005-01-01

    Full Text Available Proxy adalah bagian dari protokol yang berfungsi sebagai link untuk host tunggal atau sebagai link untuk beberapa host antarajaringan dan jaringan lain. Proxy wingate adalah software yang digunakan untuk berbagi koneksi internet melalui satu alamat IPyang terintegrasi ke internet.

  3. Climatic regions as an indicator of forest coarse and fine woody debris carbon stocks in the United States

    Science.gov (United States)

    Christopher W. Woodall; Greg C. Liknes

    2008-01-01

    Coarse and fine woody debris are substantial forest ecosystem carbon stocks; however, there is a lack of understanding how these detrital carbon stocks vary across forested landscapes. Because forest woody detritus production and decay rates may partially depend on climatic conditions, the accumulation of coarse and fine woody debris carbon stocks in forests may be...

  4. Sources and proxy potential of long chain alkyl diols in lacustrine environments.

    NARCIS (Netherlands)

    Rampen, Sebastiaan W.; Datema, Mariska; Rodrigo-Gámiz, M.; Schouten, Stefan; Reichart, Gert-Jan; Sinninghe Damste, Jaap S.

    2014-01-01

    Long chain 1,13- and 1,15-alkyl diols form the base of a number of recently proposed proxies used for climate reconstruction. However, the sources of these lipids and environmental controls on their distribution are still poorly constrained. We have analyzed the long chain alkyl diol (LCD)

  5. Sources and proxy potential of long chain alkyl diols in lacustrine environments

    NARCIS (Netherlands)

    Rampen, S.; Datema, M.; Rodrigo-Gámiz, M.; Schouten, S.; Reichart, G.-J.; Sinninghe Damsté, J.S.

    2014-01-01

    Long chain 1,13- and 1,15-alkyl diols form the base of a number of recently proposed proxies used for climate reconstruction. However, the sources of these lipids and environmental controls on their distribution are still poorly constrained. We have analyzed the long chain alkyl diol (LCD)

  6. Climatic regions as an indicator of forest coarse and fine woody debris carbon stocks in the United States

    Directory of Open Access Journals (Sweden)

    Liknes Greg C

    2008-06-01

    Full Text Available Abstract Background Coarse and fine woody debris are substantial forest ecosystem carbon stocks; however, there is a lack of understanding how these detrital carbon stocks vary across forested landscapes. Because forest woody detritus production and decay rates may partially depend on climatic conditions, the accumulation of coarse and fine woody debris carbon stocks in forests may be correlated with climate. This study used a nationwide inventory of coarse and fine woody debris in the United States to examine how these carbon stocks vary by climatic regions and variables. Results Mean coarse and fine woody debris forest carbon stocks vary by Köppen's climatic regions across the United States. The highest carbon stocks were found in regions with cool summers while the lowest carbon stocks were found in arid desert/steppes or temperate humid regions. Coarse and fine woody debris carbon stocks were found to be positively correlated with available moisture and negatively correlated with maximum temperature. Conclusion It was concluded with only medium confidence that coarse and fine woody debris carbon stocks may be at risk of becoming net emitter of carbon under a global climate warming scenario as increases in coarse or fine woody debris production (sinks may be more than offset by increases in forest woody detritus decay rates (emission. Given the preliminary results of this study and the rather tenuous status of coarse and fine woody debris carbon stocks as either a source or sink of CO2, further research is suggested in the areas of forest detritus decay and production.

  7. Web proxy auto discovery for the WLCG

    CERN Document Server

    Dykstra, D; Blumenfeld, B; De Salvo, A; Dewhurst, A; Verguilov, V

    2017-01-01

    All four of the LHC experiments depend on web proxies (that is, squids) at each grid site to support software distribution by the CernVM FileSystem (CVMFS). CMS and ATLAS also use web proxies for conditions data distributed through the Frontier Distributed Database caching system. ATLAS & CMS each have their own methods for their grid jobs to find out which web proxies to use for Frontier at each site, and CVMFS has a third method. Those diverse methods limit usability and flexibility, particularly for opportunistic use cases, where an experiment’s jobs are run at sites that do not primarily support that experiment. This paper describes a new Worldwide LHC Computing Grid (WLCG) system for discovering the addresses of web proxies. The system is based on an internet standard called Web Proxy Auto Discovery (WPAD). WPAD is in turn based on another standard called Proxy Auto Configuration (PAC). Both the Frontier and CVMFS clients support this standard. The input into the WLCG system comes from squids regis...

  8. Lithium in Brachiopods - proxy for seawater evolution?

    Science.gov (United States)

    Gaspers, Natalie; Magna, Tomas; Tomasovych, Adam; Henkel, Daniela

    2017-04-01

    Marine biogenic carbonates have the potential to serve as a proxy for evolution of seawater chemistry. In order to compile a record of the past and recent δ7Li in the oceans, foraminifera shells, scleractinian corals and belemnites have been used. However, only a foraminifera-based record appears to more accurately reflect the Li isotope composition of ocean water. At present, this record is available for the Cenozoic with implications for major events during this period of time, including K/T event [1]. A record for the entire Phanerozoic has not yet been obtained. In order to extend this record to the more distant past, Li elemental/isotope systematics of brachiopods were investigated because these marine animals were already present in Early Cambrian oceans and because they are less sensitive to diagenesis-induced modifications due to their shell mineralogy (low-Mg calcite). The preliminary data indicates a species-, temperature- and salinity-independent behavior of Li isotopes in brachiopod shells. Also, no vital effects have been observed for different shell parts. The consistent offset of -4‰ relative to modern seawater is in accordance with experimental data [2]. Further data are now being collected for Cenozoic specimens to more rigorously test brachiopods as possible archives of past seawater in comparison to the existing foraminiferal records. [1] Misra & Froelich (2012) Science 335, 818-823 [2] Marriott et al. (2004) Chem Geol 212, 5-15

  9. Temperature variations in the southern Great Lakes during the last deglaciation: Comparison between pollen and GDGT proxies

    Science.gov (United States)

    Watson, Benjamin I.; Williams, John W.; Russell, James M.; Jackson, Stephen T.; Shane, Linda; Lowell, Thomas V.

    2018-02-01

    Our understanding of deglacial climate history in the southern Great Lakes region of the United States is primarily based upon fossil pollen data, with few independent and multi-proxy climate reconstructions. Here we introduce a new, well-dated fossil pollen record from Stotzel-Leis, OH, and a new deglacial temperature record based on branched glycerol dialkyl glycerol tetraethers (brGDGTs) at Silver Lake, OH. We compare these new data to previously published records and to a regional stack of pollen-based temperature reconstructions from Stotzel-Leis, Silver Lake, and three other well-dated sites. The new and previously published pollen records at Stotzel-Leis are similar, but our new age model brings vegetation events into closer alignment with known climatic events such as the Younger Dryas (YD). brGDGT-inferred temperatures correlate strongly with pollen-based regional temperature reconstructions, with the strongest correlation obtained for a global soil-based brGDGT calibration (r2 = 0.88), lending confidence to the deglacial reconstructions and the use of brGDGT and regional pollen stacks as paleotemperature proxies in eastern North America. However, individual pollen records show large differences in timing, rates, and amplitudes of inferred temperature change, indicating caution with paleoclimatic inferences based on single-site pollen records. From 16.0 to 10.0ka, both proxies indicate that regional temperatures rose by ∼10 °C, roughly double the ∼5 °C estimates for the Northern Hemisphere reported in prior syntheses. Change-point analysis of the pollen stack shows accelerated warming at 14.0 ± 1.2ka, cooling at 12.6 ± 0.4ka, and warming from 11.6 ± 0.5ka into the Holocene. The timing of Bølling-Allerød (B-A) warming and YD onset in our records lag by ∼300-500 years those reported in syntheses of temperature records from the northern mid-latitudes. This discrepancy is too large to be attributed to uncertainties in radiocarbon dating, and

  10. Persistent positive North Atlantic oscillation mode dominated the Medieval Climate Anomaly.

    Science.gov (United States)

    Trouet, Valérie; Esper, Jan; Graham, Nicholas E; Baker, Andy; Scourse, James D; Frank, David C

    2009-04-03

    The Medieval Climate Anomaly (MCA) was the most recent pre-industrial era warm interval of European climate, yet its driving mechanisms remain uncertain. We present here a 947-year-long multidecadal North Atlantic Oscillation (NAO) reconstruction and find a persistent positive NAO during the MCA. Supplementary reconstructions based on climate model results and proxy data indicate a clear shift to weaker NAO conditions into the Little Ice Age (LIA). Globally distributed proxy data suggest that this NAO shift is one aspect of a global MCA-LIA climate transition that probably was coupled to prevailing La Niña-like conditions amplified by an intensified Atlantic meridional overturning circulation during the MCA.

  11. Reconstruction of late Quaternary marine and terrestrial environmental conditions of Northwest Africa and Southeast Australia : a multiple organic proxy study using marine sediments

    NARCIS (Netherlands)

    Alfama Lopes dos Santos, R.

    2012-01-01

    NW Africa and SE Australia are regions which are particularly vulnerable to climate change. In this thesis, organic proxies are used from marine sediment cores to reconstruct past environmental conditions from these areas. In sediments from NW Africa, the UK'37 showed an efficient proxy for sea

  12. Indication of climatically induced natural eutrophication during the early Holocene period, based on annually laminated sediment from Lake Holzmaar, Germany

    OpenAIRE

    C. Brüchmann; Negendank, Jörg F W

    2004-01-01

    A multidisciplinary study is presented for the period from 10,128–9102±10 cal BP from Lake Holzmaar in western Germany. Concurrent signals in sediment chemistry and diatom assemblages are recorded in the varved sediment sequence, and several distinct periods in the lake's response to climatic amelioration during the early Holocene period are revealed. Diatom-based transfer functions were used to estimate the lake's trophic status. In conjunction with high-resolution geochemical analysis, thes...

  13. Predicting young athletes’ motivational indices as a function of their perceptions of the coach- and peer-created climate

    OpenAIRE

    Vazou, Spiridoula; Ntoumanis, Nikos; Duda, Joan L.

    2006-01-01

    Objectives: The purpose of this study was to examine the additive and interactive influence of perceptions of the coach- and peer-created motivational climates (MC) on affective (physical self-worth, enjoyment, trait anxiety) and behavioural (exerted effort as rated by the coach) responses of young athletes. Age and gender differences in athletes’ views regarding these psychological environments were also examined. Design: Cross-sectional; participants responded to a numb...

  14. Relationships between forest fine and coarse woody debris carbon stocks across latitudinal gradients in the United States as an indicator of climate change effects

    Science.gov (United States)

    C.W. Woodall; G.C. Liknes

    2008-01-01

    Coarse and fine woody materials (CWD and FWD) are substantial forest ecosystem carbon (C) stocks. There is a lack of understanding how these detritus C stocks may respond to climate change. This study used a nation-wide inventory of CWD and FWD in the United States to examine how these C stocks vary by latitude. Results indicate that the highest CWD and FWD C stocks...

  15. Millennial reconstructions: what can we learn from limited proxy data?

    Science.gov (United States)

    Annan, J. D.; Hargreaves, J. C.

    2011-12-01

    Reconstructions of the past millennium can help us to understand recent and future climate change, by placing the recent anthropogenically-forced changes in the context of natural variability. Proxy data prior to the instrumental era are, however, extremely limited, which raises the question of how well we can truly hope to understand the past. Until recently, temperature reconstructions over the past millennium have primarily used statistical regression-based methods, however approaches using data assimilation methodology (in which observational data are blended with dynamical climate models) have shown great potential and are being increasingly adopted. However, rigorous validation of these methods has been somewhat limited. Here we will present the results of some investigations into the performance, and the potential, of data assimilation approaches to estimate the climate state. We use a massive ensemble of the LOVECLIM model to generate precise results which (through being formally optimal) may be considered an upper bound on the performance of more realistic approaches. We show that the limited precision and volume of data places a severe constraint on our ability to reliably reconstruct past climate variability, especially prior to the middle of the last millennium.

  16. Cooperative Proxy Caching for Wireless Base Stations

    Directory of Open Access Journals (Sweden)

    James Z. Wang

    2007-01-01

    Full Text Available This paper proposes a mobile cache model to facilitate the cooperative proxy caching in wireless base stations. This mobile cache model uses a network cache line to record the caching state information about a web document for effective data search and cache space management. Based on the proposed mobile cache model, a P2P cooperative proxy caching scheme is proposed to use a self-configured and self-managed virtual proxy graph (VPG, independent of the underlying wireless network structure and adaptive to the network and geographic environment changes, to achieve efficient data search, data cache and date replication. Based on demand, the aggregate effect of data caching, searching and replicating actions by individual proxy servers automatically migrates the cached web documents closer to the interested clients. In addition, a cache line migration (CLM strategy is proposed to flow and replicate the heads of network cache lines of web documents associated with a moving mobile host to the new base station during the mobile host handoff. These replicated cache line heads provide direct links to the cached web documents accessed by the moving mobile hosts in the previous base station, thus improving the mobile web caching performance. Performance studies have shown that the proposed P2P cooperative proxy caching schemes significantly outperform existing caching schemes.

  17. Fine-scale geographic variation in photosynthetic-related traits of Picea glauca seedlings indicates local adaptation to climate.

    Science.gov (United States)

    Benomar, Lahcen; Lamhamedi, Mohammed S; Villeneuve, Isabelle; Rainville, André; Beaulieu, Jean; Bousquet, Jean; Margolis, Hank A

    2015-08-01

    Climate-related variations in functional traits of boreal tree species can result both from physiological acclimation and genetic adaptation of local populations to their biophysical environment. To improve our understanding and prediction of the physiological and growth responses of populations to climate change, we studied the role of climate of seed origin in determining variations in functional traits and its implications for tree improvement programs for a commonly reforested boreal conifer, white spruce (Picea glauca (Moench) Voss). We evaluated growth, root-to-shoot ratio (R/S), specific leaf area (SLA), needle nitrogen (N(mass)), total non-structural carbohydrates (NSC) and photosynthetic traits of 3-year-old seedlings in a greenhouse experiment using seed from six seed orchards (SO) representing the different regions where white spruce is reforested in Québec. Height and total dry mass (TDM) were positively correlated with photosynthetic capacity (A(max)), stomatal conductance (g(s)) and mesophyll conductance (g(m)). Total dry mass, but not height growth, was strongly correlated with latitude of seed origin (SO) and associated climate variables. A(max), g(s), g(m) and more marginally, photosynthetic nitrogen-use efficiency (PNUE) were positively associated with the mean July temperature of the SO, while water use efficiency (WUE) was negatively associated. Maximum rates of carboxylation (V(cmax)), maximum rates of electron transport (J(max)), SLA, N(mass), NSC and R/S showed no pattern. Our results did not demonstrate a higher Amax for northern seed orchards, although this has been previously hypothesized as an adaptation mechanism for maintaining carbon uptake in northern regions. We suggest that gs, gm, WUE and PNUE are the functional traits most associated with fine-scale geographic clines and with the degree of local adaptation of white spruce populations to their biophysical environments. These geographic patterns may reflect in situ adaptive genetic

  18. Holocene moisture and East Asian summer monsoon evolution in the northeastern Tibetan Plateau recorded by Lake Qinghai and its environs: A review of conflicting proxies

    Science.gov (United States)

    Chen, Fahu; Wu, Duo; Chen, Jianhui; Zhou, Aifeng; Yu, Junqing; Shen, Ji; Wang, Sumin; Huang, Xiaozhong

    2016-12-01

    Climatic and environmental changes in the northeastern Tibetan Plateau are controlled by the Asian summer monsoon (ASM) and the westerlies, two key circulation components of the global climate system which directly affect a large human population and associated ecosystems in eastern Asia. During the past few decades, a series of Holocene palaeoclimatic records have been obtained from sediment cores from Lake Qinghai and from various other geological archives in the surrounding area of the northeastern Tibetan Plateau. However, because of uncertainties regarding the sediment chronologies and the climatic significance of the proxies used, the nature of Holocene climatic changes in the region remains unclear and even controversial. Here we review all major classes of the published data from drilled cores from Lake Qinghai, as well as other evidence from lakes and aeolian deposits from surrounding areas, in order to reconstruct changes in moisture patterns and possible summer monsoon evolution in the area during the Holocene. Combining the results of moisture and precipitation proxies such as vegetation history, pollen-based precipitation reconstruction, aeolian activity, lake water depth/lake level changes, salinity and sediment redness, we conclude that moisture and precipitation began to increase in the early Holocene, reached their maximum during the middle Holocene, and decreased during the late Holocene - similar to the pattern of the East Asian summer monsoon (EASM) in northern China. It is clear that the region experienced a relatively dry climate and weak EASM during the early Holocene, as indicated by relatively low tree pollen percentages and fluctuating pollen concentrations; generally low lake levels of Lake Qinghai and the adjacent Lake Hurleg and Lake Toson in the Qaidam Basin; and widely distributed aeolian sand deposition in the Lake Qinghai Basin and the nearby Gonghe Basin to the south, and in the eastern Qaidam Basin to the west. We argue that the

  19. Applying Least Absolute Shrinkage Selection Operator and Akaike Information Criterion Analysis to Find the Best Multiple Linear Regression Models between Climate Indices and Components of Cow's Milk.

    Science.gov (United States)

    Marami Milani, Mohammad Reza; Hense, Andreas; Rahmani, Elham; Ploeger, Angelika

    2016-07-23

    This study focuses on multiple linear regression models relating six climate indices (temperature humidity THI, environmental stress ESI, equivalent temperature index ETI, heat load HLI, modified HLI (HLI new ), and respiratory rate predictor RRP) with three main components of cow's milk (yield, fat, and protein) for cows in Iran. The least absolute shrinkage selection operator (LASSO) and the Akaike information criterion (AIC) techniques are applied to select the best model for milk predictands with the smallest number of climate predictors. Uncertainty estimation is employed by applying bootstrapping through resampling. Cross validation is used to avoid over-fitting. Climatic parameters are calculated from the NASA-MERRA global atmospheric reanalysis. Milk data for the months from April to September, 2002 to 2010 are used. The best linear regression models are found in spring between milk yield as the predictand and THI, ESI, ETI, HLI, and RRP as predictors with p -value < 0.001 and R ² (0.50, 0.49) respectively. In summer, milk yield with independent variables of THI, ETI, and ESI show the highest relation ( p -value < 0.001) with R ² (0.69). For fat and protein the results are only marginal. This method is suggested for the impact studies of climate variability/change on agriculture and food science fields when short-time series or data with large uncertainty are available.

  20. Quantifying the effect of seasonal and vertical habitat tracking on planktonic foraminifera proxies

    Science.gov (United States)

    Jonkers, Lukas; Kučera, Michal

    2017-06-01

    The composition of planktonic foraminiferal (PF) calcite is routinely used to reconstruct climate variability. However, PF ecology leaves a large imprint on the proxy signal: seasonal and vertical habitats of PF species vary spatially, causing variable offsets from annual mean surface conditions recorded by sedimentary assemblages. PF seasonality changes with temperature in a way that minimises the environmental change that individual species experience and it is not unlikely that changes in depth habitat also result from such habitat tracking. While this behaviour could lead to an underestimation of spatial or temporal trends as well as of variability in proxy records, most palaeoceanographic studies are (implicitly) based on the assumption of a constant habitat. Up to now, the effect of habitat tracking on foraminifera proxy records has not yet been formally quantified on a global scale. Here we attempt to characterise this effect on the amplitude of environmental change recorded in sedimentary PF using core top δ18O data from six species. We find that the offset from mean annual near-surface δ18O values varies with temperature, with PF δ18O indicating warmer than mean conditions in colder waters (on average by -0.1 ‰ (equivalent to 0.4 °C) per °C), thus providing a first-order quantification of the degree of underestimation due to habitat tracking. We use an empirical model to estimate the contribution of seasonality to the observed difference between PF and annual mean δ18O and use the residual Δδ18O to assess trends in calcification depth. Our analysis indicates that given an observation-based model parametrisation calcification depth increases with temperature in all species and sensitivity analysis suggests that a temperature-related seasonal habitat adjustment is essential to explain the observed isotope signal. Habitat tracking can thus lead to a significant reduction in the amplitude of recorded environmental change. However, we show that this

  1. Can grass phytoliths and indices be relied on during vegetation and climate interpretations in the eastern Himalayas? Studies from Darjeeling and Arunachal Pradesh, India

    Science.gov (United States)

    Biswas, Oindrila; Ghosh, Ruby; Paruya, Dipak Kumar; Mukherjee, Biswajit; Thapa, Kishore Kumar; Bera, Subir

    2016-02-01

    While documenting the vegetation response to climatic changes in mountains, the use of grass phytolith data relies on the ability of phytolith assemblages or indices to differentiate the elevationally stratified vegetation zones. To infer the potential and limitations of grass phytolith assemblages and indices to reconstruct vegetation vis-à-vis climate in the Himalayan mountain regions, we analyzed phytolith assemblages from 66 dominant grasses and 153 surface soils from four different forest types along the c. 130-4000 m a.s.l. elevation gradients in the Darjeeling and Arunachal Himalayas. Grass short cell phytolith assemblages from modern grasses show significant variability with rising elevation. To test the reliability of the above observation, phytoliths from the soil samples were subjected to linear discriminant analysis (DA). DA classified 85.3% and 92.3% of the sites to their correct forest zones in the Darjeeling and Arunachal Himalayas respectively. Relative abundance of bilobate, cross, short saddle, plateau saddle, rondel and trapeziform types allow discrimination of the phytolith assemblage along the elevation gradient. Canonical correspondence analysis (CCA) on the soil phytolith data further revealed their relationships with the climatic variables. Temperature and evapotranspiration were found to be the most influential for differential distribution of grass phytolith assemblages with rising elevation in the eastern Himalayas. We also tested the reliability of phytolith indices (Ic, Iph and Fs) for tracing the dominance of different grass subfamilies in the eastern Himalayas. Ic proved to be most reliable in discriminating C3/C4 grass along the elevation gradient while Iph and Fs proved to be less reliable. We observed that in the monsoon dominated eastern Himalayas, a little adjustment in Ic index may enhance the accuracy of interpretations. In future studies more precise identification of phytolith sub-types from additional sites in the eastern

  2. A unified proxy for ENSO and PDO variability since 1650

    Directory of Open Access Journals (Sweden)

    S. McGregor

    2010-01-01

    Full Text Available In this manuscript we have attempted to consolidate the common signal in previously defined proxy reconstructions of the El Niño-Southern Oscillation into one individual proxy titled the Unified ENSO Proxy (UEP. While correlating well with the majority of input reconstructions, the UEP provides better representation of observed indices of ENSO, discrete ENSO events and documented historical chronologies of ENSO than any of these input ENSO reconstructions. Further to this, the UEP also provides a means to reconstruct the PDO/IPO multi-decadal variability of the Pacific Ocean as the low-pass filtered UEP displays multi-decadal variability that is consistent with the 20th century variability of the PDO and IPO. The UEP is then used to describe changes in ENSO variability which have occurred since 1650 focusing on changes in ENSOs variance, multi-year ENSO events, PDO-like multi-decadal variability and the effects of volcanic and solar forcing on ENSO. We find that multi-year El Niño events similar to the 1990–1995 event have occurred several times over the last 3 1/2 centuries. Consistent with earlier studies we find that volcanic forcing can induce a statistically significant change in the mean state of ENSO in the year of the eruption and a doubling of the proba