WorldWideScience

Sample records for monsoon climate area

  1. Sensible climates in monsoon Asia.

    Science.gov (United States)

    Ono, H S; Kawamura, T

    1991-06-01

    This study identifies characteristics of the geographical distribution of sensible climates and their diurnal and annual variations, and presents a classification of bioclimates in monsoon Asia by using Kawamura's discomfort index formula. During the hottest month, tropical areas and areas in central and South China are uncomfortable for humans throughout the day and night, and temperate zones in lowlands are uncomfortable during the daytime. Tropical zones are uncomfortable all year long and temperate zones in lowlands are uncomfortable during summer. Four climatic types were distinguished in monsoon Asia. Climatic type I, hyperthermal throughout the year, occurs in the tropics south of latitude 20 degrees N. Climatic type II, hyperthermal in the hottest month and comfortable in the coldest month, extends over latitudes from 20 degrees to 30 degrees N except in the highlands. Climatic type III, hyperthermal in the hottest month and hypothermal in the coldest month, encompasses temperate zones of East Asia and subtropical arid areas of northwestern India. Climatic type V, comfortable in the hottest month and hypothermal in coldest month, occurs near the southeast coast of the Soviet Union and in the highlands of the Himalayas.

  2. Aerosol and monsoon climate interactions over Asia: AEROSOL AND MONSOON CLIMATE INTERACTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhanqing [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Lau, W. K. -M. [Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Ramanathan, V. [Department of Atmospheric and Climate Sciences, University of California, San Diego California USA; Wu, G. [Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing China; Ding, Y. [National Climate Center, China Meteorological Administration, Beijing China; Manoj, M. G. [Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Liu, J. [Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Qian, Y. [Pacific Northwest National Laboratory, Richland Washington USA; Li, J. [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Zhou, T. [Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing China; Fan, J. [Pacific Northwest National Laboratory, Richland Washington USA; Rosenfeld, D. [Institute of Earth Sciences, Hebrew University, Jerusalem Israel; Ming, Y. [Geophysical Fluid Dynamic Laboratory, NOAA, Princeton New Jersey USA; Wang, Y. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena California USA; Huang, J. [College of Atmospheric Sciences, Lanzhou University, Lanzhou China; Wang, B. [Department of Atmospheric Sciences, University of Hawaii, Honolulu Hawaii USA; School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing China; Xu, X. [Chinese Academy of Meteorological Sciences, Beijing China; Lee, S. -S. [Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Cribb, M. [Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park Maryland USA; Zhang, F. [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Yang, X. [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Zhao, C. [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Takemura, T. [Research Institute for Applied Mechanics, Kyushu University, Fukuoka Japan; Wang, K. [State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science, Beijing Normal University, Beijing China; Xia, X. [Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing China; Yin, Y. [School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing China; Zhang, H. [National Climate Center, China Meteorological Administration, Beijing China; Guo, J. [Chinese Academy of Meteorological Sciences, Beijing China; Zhai, P. M. [Chinese Academy of Meteorological Sciences, Beijing China; Sugimoto, N. [National Institute for Environmental Studies, Tsukuba Japan; Babu, S. S. [Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram India; Brasseur, G. P. [Max Planck Institute for Meteorology, Hamburg Germany

    2016-11-15

    Asian monsoons and aerosols have been studied extensively which are intertwined in influencing the climate of Asia. This paper provides a comprehensive review of ample studies on Asian aerosol, monsoon and their interactions. The region is the primary source of aerosol emissions of varies species, influenced by distinct weather and climatic regimes. On continental scale, aerosols reduce surface insolation and weaken the land-ocean thermal contrast, thus inhibiting the development of monsoons. Locally, aerosol radiative effects alter the thermodynamic stability and convective potential of the lower atmosphere leading to reduced temperatures, increased atmospheric stability, and weakened wind and atmospheric circulation. The atmospheric thermodynamic state may also be altered by the aerosol serving as cloud condensation nuclei or ice nuclei. Many mechanisms have been put forth regarding how aerosols modulate the amplitude, frequency, intensity, and phase of numerous monsoon climate variables. A wide range of theoretical, observational, and modeling findings on the Asian monsoon, aerosols, and their interactions are synthesized. A new paradigm is proposed on investigating aerosol-monsoon interactions, in which natural aerosols such as desert dust, black carbon from biomass burning, and biogenic aerosols from vegetation are considered integral components of an intrinsic aerosol-monsoon climate system, subject to external forcings of global warming, anthropogenic aerosols, and land use and change. Future research on aerosol-monsoon interactions calls for an integrated approach and international collaborations based on long-term sustained observations, process measurements, and improved models, as well as using observations to constrain model simulations and projections.

  3. Impact of Climate Change on India's Monsoonal Climate: Present ...

    Indian Academy of Sciences (India)

    Expected Future Changes in Rainfall and Temperature over India under IPCC SRES A1B GHG Scenarios · Expected Future Change in Monsoon Rainfall and Annual Surface Temp for 2020's, 2050's and 2080's · Likely Future Paradox of Monsoon-ENSO Links · High-Resolution Regional Climate Change Scenarios.

  4. The Aerosol-Monsoon Climate System of Asia

    Science.gov (United States)

    Lau, William K. M.; Kyu-Myong, Kim

    2012-01-01

    In Asian monsoon countries such as China and India, human health and safety problems caused by air-pollution are worsening due to the increased loading of atmospheric pollutants stemming from rising energy demand associated with the rapid pace of industrialization and modernization. Meanwhile, uneven distribution of monsoon rain associated with flash flood or prolonged drought, has caused major loss of human lives, and damages in crop and properties with devastating societal impacts on Asian countries. Historically, air-pollution and monsoon research are treated as separate problems. However a growing number of recent studies have suggested that the two problems may be intrinsically intertwined and need to be studied jointly. Because of complexity of the dynamics of the monsoon systems, aerosol impacts on monsoons and vice versa must be studied and understood in the context of aerosol forcing in relationship to changes in fundamental driving forces of the monsoon climate system (e.g. sea surface temperature, land-sea contrast etc.) on time scales from intraseasonal variability (weeks) to climate change ( multi-decades). Indeed, because of the large contributions of aerosols to the global and regional energy balance of the atmosphere and earth surface, and possible effects of the microphysics of clouds and precipitation, a better understanding of the response to climate change in Asian monsoon regions requires that aerosols be considered as an integral component of a fully coupled aerosol-monsoon system on all time scales. In this paper, using observations and results from climate modeling, we will discuss the coherent variability of the coupled aerosol-monsoon climate system in South Asia and East Asia, including aerosol distribution and types, with respect to rainfall, moisture, winds, land-sea thermal contrast, heat sources and sink distributions in the atmosphere in seasonal, interannual to climate change time scales. We will show examples of how elevated

  5. Community level perceptions of the monsoon onset, withdrawal and climatic trends in Bangladesh

    Science.gov (United States)

    Reeve, M. A.; Abu Syed, M. D.; Hossain, P. R.; Maainuddi, G.; Mamnun, N.

    2012-04-01

    A structured questionnaire study was carried out in 6 different regions in Bangladesh in order to give insight into how the different communities define the monsoon. The respondents were asked how they define the monsoon onset and withdrawal, and by how much these can vary from year to year. They were also asked about how they perceive changes in onset and withdrawal dates and total monsoonal rainfall during the past 20 years. Bangladesh is a developing country with a large proportion of the population living in rural areas and employed in the agricultural sector. It is foreseen that these communities will be most affected by changes in the climate. These groups were considered to be the main stakeholders when considering climate change, due to the direct influence the monsoon has on their livelihood and the food supply for the entire nation. Agricultural workers were therefore the main group targeted in this study. The main aim of the study was to create a framework for defining the monsoon in order to increase the usability of results in future impact-related studies. Refining definitions according to the perceptions of the main stakeholders helps to achieve this goal. Results show that rainfall is the main parameter used in defining the monsoon onset and withdrawal. This is possibly intuitive, however the monsoon onset was considered to be considerably earlier than previous scientific studies. This could be due to pre-monsoonal rainfall, however the respondents defined this type of rainfall separately to what they called the monsoon. The monsoon is considered to start earliest in the Sylhet region in northeast Bangladesh.

  6. Evaluation of global climate models for Indian monsoon climatology

    International Nuclear Information System (INIS)

    Kodra, Evan; Ganguly, Auroop R; Ghosh, Subimal

    2012-01-01

    The viability of global climate models for forecasting the Indian monsoon is explored. Evaluation and intercomparison of model skills are employed to assess the reliability of individual models and to guide model selection strategies. Two dominant and unique patterns of Indian monsoon climatology are trends in maximum temperature and periodicity in total rainfall observed after 30 yr averaging over India. An examination of seven models and their ensembles reveals that no single model or model selection strategy outperforms the rest. The single-best model for the periodicity of Indian monsoon rainfall is the only model that captures a low-frequency natural climate oscillator thought to dictate the periodicity. The trend in maximum temperature, which most models are thought to handle relatively better, is best captured through a multimodel average compared to individual models. The results suggest a need to carefully evaluate individual models and model combinations, in addition to physical drivers where possible, for regional projections from global climate models. (letter)

  7. Effect of climate change on seasonal monsoon in Asia and its impact on the variability of monsoon rainfall in Southeast Asia

    Directory of Open Access Journals (Sweden)

    Yen Yi Loo

    2015-11-01

    Full Text Available Global warming and climate change is one of the most extensively researched and discussed topical issues affecting the environment. Although there are enough historical evidence to support the theory that climate change is a natural phenomenon, many research scientists are widely in agreement that the increase in temperature in the 20th century is anthropologically related. The associated effects are the variability of rainfall and cyclonic patterns that are being observed globally. In Southeast Asia the link between global warming and the seasonal atmospheric flow during the monsoon seasons shows varying degree of fuzziness. This study investigates the impact of climate change on the seasonality of monsoon Asia and its effect on the variability of monsoon rainfall in Southeast Asia. The comparison of decadal variation of precipitation and temperature anomalies before the 1970s found general increases which were mostly varying. But beyond the 1970s, global precipitation anomalous showed increases that almost corresponded with increases in global temperature anomalies for the same period. There are frequent changes and a shift westward of the Indian summer monsoon. Although precipitation is observed to be 70% below normal levels, in some areas the topography affects the intensity of rainfall. These shifting phenomenon of other monsoon season in the region are impacting on the variability of rainfall and the onset of monsoons in Southeast Asia and is predicted to delay for 15 days the onset of the monsoon in the future. The variability of monsoon rainfall in the SEA region is observed to be decadal and the frequency and intensity of intermittent flooding of some areas during the monsoon season have serious consequences on the human, financial, infrastructure and food security of the region.

  8. Seasonal behaviour of tidal inlets in a tropical monsoon area

    NARCIS (Netherlands)

    Lam, N.T.; Stive, M.J.F.; Verhagen, H.J.; Wang, Z.B.

    2008-01-01

    Morphodynamics of a tidal inlet system on a micro-tidal coast in a tropical monsoon influenced region is modelled and discussed. Influences of river flow and wave climate on the inlet morphology are investigated with the aid of process-based state-of-the-art numerical models. Seasonal and episodic

  9. Changes of extreme precipitation and nonlinear influence of climate variables over monsoon region in China

    KAUST Repository

    Gao, Tao; Wang, Huixia Judy; Zhou, Tianjun

    2017-01-01

    of precipitation extremes over monsoon regions in China (MRC). However, research on monsoon extremes in China and their associations with climate variables is limited. In this study, we examine the space-time variations of extreme precipitation across the MRC

  10. A mechanism for land-ocean contrasts in global monsoon trends in a warming climate

    Energy Technology Data Exchange (ETDEWEB)

    Fasullo, J. [National Center for Atmospheric Research, CAS/NCAR, Boulder, CO (United States)

    2012-09-15

    A central paradox of the global monsoon record involves reported decreases in rainfall over land during an era in which the global hydrologic cycle is both expected and observed to intensify. It is within this context that this work develops a physical basis for both interpreting the observed record and anticipating changes in the monsoons in a warming climate while bolstering the concept of the global monsoon in the context of shared feedbacks. The global-land monsoon record across multiple reanalyses is first assessed. Trends that in other studies have been taken as real are shown to likely be spurious as a result of changes in the assimilated data streams both prior to and during the satellite era. Nonetheless, based on satellite estimates, robust increases in monsoon rainfall over ocean do exist and a physical basis for this land-ocean contrast remains lacking. To address the contrast's causes, simulated trends are therefore assessed. While projections of total rainfall are inconsistent across models, the robust land-ocean contrast identified in observations is confirmed. A feedback mechanism is proposed rooted in the facts that land areas warm disproportionately relative to ocean, and onshore flow is the chief source of monsoonal moisture. Reductions in lower tropospheric relative humidity over land domains are therefore inevitable and these have direct consequences for the monsoonal convective environment including an increase in the lifting condensation level and a shift in the distribution of convection generally towards less frequent and potentially more intense events. The mechanism is interpreted as an important modulating influence on the ''rich-get-richer'' mechanism. Caveats for regional monsoons exist and are discussed. (orig.)

  11. Assessment of CORDEX-South Asia experiments for monsoonal precipitation over Himalayan region for future climate

    Science.gov (United States)

    Choudhary, A.; Dimri, A. P.

    2018-04-01

    Precipitation is one of the important climatic indicators in the global climate system. Probable changes in monsoonal (June, July, August and September; hereafter JJAS) mean precipitation in the Himalayan region for three different greenhouse gas emission scenarios (i.e. representative concentration pathways or RCPs) and two future time slices (near and far) are estimated from a set of regional climate simulations performed under Coordinated Regional Climate Downscaling Experiment-South Asia (CORDEX-SA) project. For each of the CORDEX-SA simulations and their ensemble, projections of near future (2020-2049) and far future (2070-2099) precipitation climatology with respect to corresponding present climate (1970-2005) over Himalayan region are presented. The variability existing over each of the future time slices is compared with the present climate variability to determine the future changes in inter annual fluctuations of monsoonal mean precipitation. The long-term (1970-2099) trend (mm/day/year) of monsoonal mean precipitation spatially distributed as well as averaged over Himalayan region is analyzed to detect any change across twenty-first century as well as to assess model uncertainty in simulating the precipitation changes over this period. The altitudinal distribution of difference in trend of future precipitation from present climate existing over each of the time slices is also studied to understand any elevation dependency of change in precipitation pattern. Except for a part of the Hindu-Kush area in western Himalayan region which shows drier condition, the CORDEX-SA experiments project in general wetter/drier conditions in near future for western/eastern Himalayan region, a scenario which gets further intensified in far future. Although, a gradually increasing precipitation trend is seen throughout the twenty-first century in carbon intensive scenarios, the distribution of trend with elevation presents a very complex picture with lower elevations

  12. Model Interpretation of Climate Signals: Application to the Asian Monsoon Climate

    Science.gov (United States)

    Lau, William K. M.

    2002-01-01

    This is an invited review paper intended to be published as a Chapter in a book entitled "The Global Climate System: Patterns, Processes and Teleconnections" Cambridge University Press. The author begins with an introduction followed by a primer of climate models, including a description of various modeling strategies and methodologies used for climate diagnostics and predictability studies. Results from the CLIVAR Monsoon Model Intercomparison Project (MMIP) were used to illustrate the application of the strategies to modeling the Asian monsoon. It is shown that state-of-the art atmospheric GCMs have reasonable capability in simulating the seasonal mean large scale monsoon circulation, and response to El Nino. However, most models fail to capture the climatological as well as interannual anomalies of regional scale features of the Asian monsoon. These include in general over-estimating the intensity and/or misplacing the locations of the monsoon convection over the Bay of Bengal, and the zones of heavy rainfall near steep topography of the Indian subcontinent, Indonesia, and Indo-China and the Philippines. The intensity of convection in the equatorial Indian Ocean is generally weaker in models compared to observations. Most important, an endemic problem in all models is the weakness and the lack of definition of the Mei-yu rainbelt of the East Asia, in particular the part of the Mei-yu rainbelt over the East China Sea and southern Japan are under-represented. All models seem to possess certain amount of intraseasonal variability, but the monsoon transitions, such as the onset and breaks are less defined compared with the observed. Evidences are provided that a better simulation of the annual cycle and intraseasonal variability is a pre-requisite for better simulation and better prediction of interannual anomalies.

  13. Climate variability and land cover change over the North American monsoon region (Invited)

    Science.gov (United States)

    Zeng, X.; Scheftic, W. D.; Broxton, P. D.

    2013-12-01

    The North American Monsoon System over Mexico and southwestern United States represents a weather/climate and ecosystem coupled "macrosystem". The weather and climate affect the seasonal and interannual variability of ecosystem, while the ecosystem change affects surface energy, water, and carbon fluxes that, in turn, affect weather and climate. Furthermore, long-term weather/climate data have a much coarser horizontal resolution than the satellite land cover data. Here the North American Regional Reanalysis (NARR) data at 32 km grid spacing will be combined with various satellite remote sensing products at 1 km and/or 8 km resolution from AVHRR, MODIS, and SPOT for the period of 1982 to present. Our analysis includes: a) precipitation, wind, and precipitable water data from NARR to characterize the North American monsoon; b) land cover type, normalized difference vegetation index (NDVI), green vegetation fraction, and leaf-area index (LAI) data to characterize the seasonal and interannual variability of ecosystem; c) assessing the consistency of various satellite products; and d) testing the coherence in the weather/climate and ecosystem variability.

  14. Projected hydrologic changes in monsoon-dominated Himalaya Mountain basins with changing climate and deforestation

    Science.gov (United States)

    Neupane, Ram P.; White, Joseph D.; Alexander, Sara E.

    2015-06-01

    In mountain headwaters, climate and land use changes affect short and long term site water budgets with resultant impacts on landslide risk, hydropower generation, and sustainable agriculture. To project hydrologic change associated with climate and land use changes in the Himalaya Mountains, we used the Soil and Water Assessment Tool (SWAT) calibrated for the Tamor and Seti River basins located at eastern and western margins of Nepal. Future climate change was modeled using averaged temperature and precipitation for 2080 derived from Special Report on Emission Scenarios (SRES) (B1, A1B and A2) of 16 global circulation models (GCMs). Land use change was modeled spatially and included expansion of (1) agricultural land, (2) grassland, and (3) human settlement area that were produced by considering existing land use with projected changes associated with viability of elevation and slope characteristics of the basins capable of supporting different land use type. From these simulations, higher annual stream discharge was found for all GCM-derived scenarios compared to a baseline simulation with maximum increases of 13 and 8% in SRES-A2 and SRES-A1B for the Tamor and Seti basins, respectively. On seasonal basis, we assessed higher precipitation during monsoon season in all scenarios that corresponded with higher stream discharge of 72 and 68% for Tamor and Seti basins, respectively. This effect appears to be geographically important with higher influence in the eastern Tamor basin potentially due to longer and stronger monsoonal period of that region. However, we projected minimal changes in stream discharge for the land use scenarios potentially due to higher water transmission to groundwater reservoirs associated with fractures of the Himalaya Mountains rather than changes in surface runoff. However, when combined the effects of climate and land use changes, discharge was moderately increased indicating counteracting mechanisms of hydrologic yield in these mountains

  15. Climate and land use controls over terrestrial water use efficiency in monsoon Asia.

    Science.gov (United States)

    Hanqin Tian; Chaoqun Lu; Guangsheng Chen; Xiaofeng Xu; Mingliang Liu; et al

    2011-01-01

    Much concern has been raised regarding how and to what extent climate change and intensive human activities have altered water use efficiency (WUE, amount of carbon uptake per unit of water use) in monsoon Asia. By using a process-based ecosystem model [dynamic land ecosystem model (DLEM)], we examined effects of climate change, land use/cover change, and land...

  16. Changes of extreme precipitation and nonlinear influence of climate variables over monsoon region in China

    KAUST Repository

    Gao, Tao

    2017-07-19

    The El Niño-Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), North Atlantic Oscillation (NAO), Atlantic Multidecadal Oscillation (AMO) and Pacific decadal oscillation (PDO) are well understood to be major drivers for the variability of precipitation extremes over monsoon regions in China (MRC). However, research on monsoon extremes in China and their associations with climate variables is limited. In this study, we examine the space-time variations of extreme precipitation across the MRC, and assess the time-varying influences of the climate drivers using Bayesian dynamic linear regression and their combined nonlinear effects through fitting generalized additive models. Results suggest that the central-east and south China is dominated by less frequent but more intense precipitation. Extreme rainfalls show significant positive trends, coupled with a significant decline of dry spells, indicating an increasing chance of occurrence of flood-induced disasters in the MRC during 1960–2014. Majority of the regional indices display some abrupt shifts during the 1990s. The influences of climate variables on monsoon extremes exhibit distinct interannual or interdecadal variations. IOD, ENSO and AMO have strong impacts on monsoon and extreme precipitation, especially during the 1990s, which is generally consistent with the abrupt shifts in precipitation regimes around this period. Moreover, ENSO mainly affects moderate rainfalls and dry spells, while IOD has a more significant impact on precipitation extremes. These findings could be helpful for improving the forecasting of monsoon extremes in China and the evaluations of climate models.

  17. Identification of tipping elements of the Indian Summer Monsoon using climate network approach

    Science.gov (United States)

    Stolbova, Veronika; Surovyatkina, Elena; Kurths, Jurgen

    2015-04-01

    Spatial and temporal variability of the rainfall is a vital question for more than one billion of people inhabiting the Indian subcontinent. Indian Summer Monsoon (ISM) rainfall is crucial for India's economy, social welfare, and environment and large efforts are being put into predicting the Indian Summer Monsoon. For predictability of the ISM, it is crucial to identify tipping elements - regions over the Indian subcontinent which play a key role in the spatial organization of the Indian monsoon system. Here, we use climate network approach for identification of such tipping elements of the ISM. First, we build climate networks of the extreme rainfall, surface air temperature and pressure over the Indian subcontinent for pre-monsoon, monsoon and post-monsoon seasons. We construct network of extreme rainfall event using observational satellite data from 1998 to 2012 from the Tropical Rainfall Measuring Mission (TRMM 3B42V7) and reanalysis gridded daily rainfall data for a time period of 57 years (1951-2007) (Asian Precipitation Highly Resolved Observational Data Integration Towards the Evaluation of Water Resources, APHRODITE). For the network of surface air temperature and pressure fields, we use re-analysis data provided by the National Center for Environmental Prediction and National Center for Atmospheric Research (NCEP/NCAR). Second, we filter out data by coarse-graining the network through network measures, and identify tipping regions of the ISM. Finally, we compare obtained results of the network analysis with surface wind fields and show that occurrence of the tipping elements is mostly caused by monsoonal wind circulation, migration of the Intertropical Convergence Zone (ITCZ) and Westerlies. We conclude that climate network approach enables to select the most informative regions for the ISM, providing realistic description of the ISM dynamics with fewer data, and also help to identify tipping regions of the ISM. Obtained tipping elements deserve a

  18. Future projection of mean and variability of the Asian Summer Monsoon and Indian Ocean Climate systems

    Energy Technology Data Exchange (ETDEWEB)

    Annamalai, H. [Univ. of Hawaii, Honolulu, HI (United States)

    2014-09-15

    The overall goal of this project is to assess the ability of the CMIP3/5 models to simulate the Indian-Ocean monsoon systems. The PI along with post-docs investigated research issues ranging from synoptic systems to long-term trends over the Asian monsoon region. The PI applied diagnostic tools such as moist static energy (MSE) to isolate: the moist and radiative processes responsible for extended monsoon breaks over South Asia, precursors in the ENSO-monsoon association, reasons for the drying tendency over South Asia and the possible effect on tropical Indian Ocean climate anomalies influencing certain aspects of ENSO characteristics. By diagnosing various observations and coupled model simulations, we developed working hypothesis and tested them by carrying out sensitivity experiments with both linear and nonlinear models. Possible physical and dynamical reasons for model sensitivities were deduced. On the teleconnection front, the ability of CMIP5 models in representing the monsoon-desert mechanism was examined recently. Further more, we have applied a suite of diagnostics and have performed an in depth analysis on CMIP5 integrations to isolate the possible reasons for the ENSO-monsoon linkage or lack thereof. The PI has collaborated with Dr. K.R. Sperber of PCMDI and other CLIVAR Asian-Australian monsoon panel members in understanding the ability of CMIP3/5 models in capturing monsoon and its spectrum of variability. The objective and process-based diagnostics aided in selecting models that best represent the present-day monsoon and its variability that are then employed for future projections. Two major highlights were an invitation to write a review on present understanding monsoons in a changing climate in Nature Climate Change, and identification of an east-west shift in observed monsoon rainfall (more rainfall over tropical western Pacific and drying tendency over South Asia) in the last six decades and attributing that shift to SST rise over the tropical

  19. Diagnosis of the Asian summer monsoon variability and the climate prediction of monsoon precipitation via physical decomposition

    Science.gov (United States)

    Lim, Young-Kwon

    This study investigates the space-time evolution of the dominant modes that constitute the Asian summer monsoon (ASM), and, as an ultimate goal, the climate prediction of the ASM rainfall. Precipitation and other synoptic variables during the prominent life cycle of the ASM (May 21 to September 17) are used to show the detailed features of dominant modes, which are identified as the seasonal cycle, the ISO defined by the 40--50 day intraseasonal oscillation including the Madden-Julian oscillation, and the El Nino mode. The present study reveals that the ISO is the second largest component of the ASM rainfall variation. Correlation analysis indicates that ISO explains a larger fraction of the variance of the observed precipitation (without climatology) than the ENSO mode. The dominant ISO signal faithfully explains the northward propagation of the ISO toward the Asian continent causing intraseasonal active/break periods. The interannual variation of the ISO strength suggests that the ENSO exerts some influence on the ISO. The composite convective ISO anomaly and Kelvin-Rossby wave response over the Indian Ocean shows that the ISO tends to be stronger during the early stage of the ASM than normal in El Nino (La Nina) years, indicating greater (smaller) possibility of ISO-related extreme rainfall over India, Bangladesh, and the Bay of Bengal. The ENSO mode reveals that the following factors affect the evolution of the ASM system in El Nino (La Nina) years. (1) The anomalous sea surface temperature and sea level pressure over the Indian Ocean during the early stage of the ASM weaken (enhance) the meridional pressure gradient. (2) As a result, the westerly jet and the ensuing moisture transport toward India and the Bay of Bengal become weak (strong) and delayed (expedited), providing a less (more) favorable condition for regional monsoon onsets. (3) The Walker circulation anomaly results in an enhanced subsidence (ascent) and drought (flood) over the Maritime continent

  20. A model perspective on orbital forcing of monsoons and Mediterranean climate using EC-Earth

    NARCIS (Netherlands)

    Bosmans, J.H.C.

    2014-01-01

    This thesis focuses on orbitally forced changes of monsoons and Mediterranean climate. Changes in the shape of the Earths orbit around the Sun and its rotational axis govern the seasonal and latitudinal distribution of incoming solar radiation on time scales of thousands to millions of years. The

  1. From monsoon to marine productivity in the Arabian Sea: insights from glacial and interglacial climates

    Science.gov (United States)

    Le Mézo, Priscilla; Beaufort, Luc; Bopp, Laurent; Braconnot, Pascale; Kageyama, Masa

    2017-07-01

    The current-climate Indian monsoon is known to boost biological productivity in the Arabian Sea. This paradigm has been extensively used to reconstruct past monsoon variability from palaeo-proxies indicative of changes in surface productivity. Here, we test this paradigm by simulating changes in marine primary productivity for eight contrasted climates from the last glacial-interglacial cycle. We show that there is no straightforward correlation between boreal summer productivity of the Arabian Sea and summer monsoon strength across the different simulated climates. Locally, productivity is fuelled by nutrient supply driven by Ekman dynamics. Upward transport of nutrients is modulated by a combination of alongshore wind stress intensity, which drives coastal upwelling, and by a positive wind stress curl to the west of the jet axis resulting in upward Ekman pumping. To the east of the jet axis there is however a strong downward Ekman pumping due to a negative wind stress curl. Consequently, changes in coastal alongshore stress and/or curl depend on both the jet intensity and position. The jet position is constrained by the Indian summer monsoon pattern, which in turn is influenced by the astronomical parameters and the ice sheet cover. The astronomical parameters are indeed shown to impact wind stress intensity in the Arabian Sea through large-scale changes in the meridional gradient of upper-tropospheric temperature. However, both the astronomical parameters and the ice sheets affect the pattern of wind stress curl through the position of the sea level depression barycentre over the monsoon region (20-150° W, 30° S-60° N). The combined changes in monsoon intensity and pattern lead to some higher glacial productivity during the summer season, in agreement with some palaeo-productivity reconstructions.

  2. Changes in the Asian monsoon climate during 1700-1850 induced by preindustrial cultivation.

    Science.gov (United States)

    Takata, Kumiko; Saito, Kazuyuki; Yasunari, Tetsuzo

    2009-06-16

    Preindustrial changes in the Asian summer monsoon climate from the 1700s to the 1850s were estimated with an atmospheric general circulation model (AGCM) using historical global land cover/use change data reconstructed for the last 300 years. Extended cultivation resulted in a decrease in monsoon rainfall over the Indian subcontinent and southeastern China and an associated weakening of the Asian summer monsoon circulation. The precipitation decrease in India was marked and was consistent with the observational changes derived from examining the Himalayan ice cores for the concurrent period. Between the 1700s and the 1850s, the anthropogenic increases in greenhouse gases and aerosols were still minor; also, no long-term trends in natural climate variations, such as those caused by the ocean, solar activity, or volcanoes, were reported. Thus, we propose that the land cover/use change was the major source of disturbances to the climate during that period. This report will set forward quantitative examination of the actual impacts of land cover/use changes on Asian monsoons, relative to the impact of greenhouse gases and aerosols, viewed in the context of global warming on the interannual, decadal, and centennial time scales.

  3. ENSO, IOD and Indian Summer Monsoon in NCEP climate forecast system

    Energy Technology Data Exchange (ETDEWEB)

    Pokhrel, Samir; Chaudhari, H.S.; Saha, Subodh K.; Dhakate, Ashish; Yadav, R.K.; Salunke, Kiran; Mahapatra, S.; Rao, Suryachandra A. [Indian Institute of Tropical Meteorology, Pashan, Pune (India)

    2012-11-15

    El Nino-Southern Oscillation (ENSO), Indian Ocean Dipole (IOD) and Indian Summer Monsoon rainfall features are explored statistically and dynamically using National Centers for Environment Prediction (NCEP) Climate Forecast System (CFSv1) freerun in relation to observations. The 100 years of freerun provides a sufficiently long homogeneous data set to find out the mean state, periodicity, coherence among these climatic events and also the influence of ENSO and IOD on the Indian monsoon. Differences in the occurrence of seasonal precipitation between the observations and CFS freerun are examined as a coupled ocean-atmosphere system. CFS simulated ENSO and IOD patterns and their associated tropical Walker and regional Hadley circulation in pure ENSO (PEN), pure IOD (PIO) and coexisting ENSO-IOD (PEI) events have some similarity to the observations. PEN composites are much closer to the observation as compared to PIO and PEI composites, which suggest a better ENSO prediction and its associated teleconnections as compared to IOD and combined phenomenon. Similar to the observation, the model simulation also show that the decrease in the Indian summer monsoon rainfall during ENSO phases is associated with a descending motion of anomalous Walker circulation and the increase in the Indian summer monsoon rainfall during IOD phase is associated with the ascending branch of anomalous regional Hadley circulation. During co-existing ENSO and IOD years, however, the fate of Indian summer monsoon is dictated by the combined influence of both of them. The shift in the anomalous descending and ascending branches of the Walker and Hadley circulation may be somewhat attributed to the cold (warm) bias over eastern (western) equatorial Indian Ocean basin, respectively in the model. This study will be useful for identifying some of the limitations of the CFS model and consequently it will be helpful in improving the model to unravel the realistic coupled ocean-atmosphere interactions

  4. Climatic Changes and Evaluation of Their Effects on Agriculture in Asian Monsoon Region- A project of GRENE-ei programs in Japan

    Science.gov (United States)

    Mizoguchi, M.; Matsumoto, J.; Takahashi, H. G.; Tanaka, K.; Kuwagata, T.

    2015-12-01

    It is important to predict climate change correctly in regional scale and to build adaptation measures and mitigation measures in the Asian monsoon region where more than 60 % of the world's population are living. The reliability of climate change prediction model is evaluated by the reproducibility of past climate in general. However, because there are many developing countries in the Asian monsoon region, adequate documentations of past climate which are needed to evaluate the climate reproducibility have not been prepared. In addition, at present it is difficult to get information on wide-area agricultural meteorological data which affect the growth of agricultural crops when considering the impact on agriculture of climate. Therefore, we have started a research project entitled "Climatic changes and evaluation of their effects on agriculture in Asian monsoon region (CAAM)" under the research framework of the Green Network of Excellence (GRENE) for the Japanese fiscal years from 2011 to 2015 supported by the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT). This project aims to improve the reliability of future climate prediction and to develop the information platform which will be useful to design adaptation and mitigation strategies in agriculture against the predicted climatic changes in Asian monsoon regions. What is GRENE?Based on the new growth strategy which was approved by the Cabinet of Japan in June 2010, Green Network of Excellence program (GRENE) has started under MEXT from FY 2011. The objectives of this program are that the domestic leading universities work together strategically and promote a comprehensive human resource development and research of the highest level in the world while sharing research resources and research goals. In the field of environmental information, it is required that universities and research institutions, which are working on issues such as adaptation to climate change, cooperate to

  5. Failure of CMIP5 climate models in simulating post-1950 decreasing trend of Indian monsoon

    Science.gov (United States)

    Saha, Anamitra; Ghosh, Subimal; Sahana, A. S.; Rao, E. P.

    2014-10-01

    Impacts of climate change on Indian Summer Monsoon Rainfall (ISMR) and the growing population pose a major threat to water and food security in India. Adapting to such changes needs reliable projections of ISMR by general circulation models. Here we find that, majority of new generation climate models from Coupled Model Intercomparison Project phase5 (CMIP5) fail to simulate the post-1950 decreasing trend of ISMR. The weakening of monsoon is associated with the warming of Southern Indian Ocean and strengthening of cyclonic formation in the tropical western Pacific Ocean. We also find that these large-scale changes are not captured by CMIP5 models, with few exceptions, which is the reason of this failure. Proper representation of these highlighted geophysical processes in next generation models may improve the reliability of ISMR projections. Our results also alert the water resource planners to evaluate the CMIP5 models before using them for adaptation strategies.

  6. Interdecadal modulation of El Niño teleconnection on monsoon Asia climate over the past five centuries

    Science.gov (United States)

    Li, J.; Xie, S. P.

    2017-12-01

    The El Niño influence on monsoon Asia climate weakened during the mid-20th century and strenthened substantially after the late 1970s. Exploring the nature of such an interdecadal variation is constrained by short instrumental records. Here we synthesize the Indo-Pacific tree-rings and coral records to reconstruct monsoon Asia temperature and moisture change during the past five centuries, and show that the interdecadal modulation of El Niño teleconnection on monsoon Asia climate is a robust feature beyond the instrumenal era. Comparison with proxy El Niño records indicates that the El Niño-monsoon Asia climate teleconnection is controlled by interdecadal changes in ENSO variance, with strong (weak) teleconnection in periods of high (low) variance, respectively.

  7. Indian monsoon variations during three contrasting climatic periods: the Holocene, Heinrich Stadial 2 and the last interglacial-glacial transition

    Science.gov (United States)

    Zorzi, Coralie; Fernanda Sanchez Goñi, Maria; Anupama, Krishnamurthy; Prasad, Srinivasan; Hanquiez, Vincent; Johnson, Joel; Giosan, Liviu

    2016-04-01

    In contrast to the East Asian and African monsoons the Indian monsoon is still poorly documented throughout the last climatic cycle (last 135,000 years). Pollen analysis from two marine sediment cores (NGHP-01-16A and NGHP-01-19B) collected from the offshore Godavari and Mahanadi basins, both located in the Core Monsoon Zone (CMZ) reveals changes in Indian summer monsoon variability and intensity during three contrasting climatic periods: the Holocene, the Heinrich Stadial (HS) 2 and the Marine Isotopic Stage (MIS) 5/4 during the ice sheet growth transition. During the first part of the Holocene between 11,300 and 4,200 cal years BP, characterized by high insolation (minimum precession, maximum obliquity), the maximum extension of the coastal forest and mangrove reflects high monsoon rainfall. This climatic regime contrasts with that of the second phase of the Holocene, from 4,200 cal years BP to the present, marked by the development of drier vegetation in a context of low insolation (maximum precession, minimum obliquity). The historical period in India is characterized by an alternation of strong and weak monsoon centennial phases that may reflect the Medieval Climate Anomaly and the Little Ice Age, respectively. During the HS 2, a period of low insolation and extensive iceberg discharge in the North Atlantic Ocean, vegetation was dominated by grassland and dry flora indicating pronounced aridity as the result of a weak Indian summer monsoon. The MIS 5/4 glaciation, also associated with low insolation but moderate freshwater fluxes, was characterized by a weaker reduction of the Indian summer monsoon and a decrease of seasonal contrast as recorded by the expansion of dry vegetation and the development of Artemisia, respectively. Our results support model predictions suggesting that insolation changes control the long term trend of the Indian monsoon precipitation, but its millennial scale variability and intensity are instead modulated by atmospheric

  8. Dominance of climate warming effects on recent drying trends over wet monsoon regions

    Science.gov (United States)

    Park, Chang-Eui; Jeong, Su-Jong; Ho, Chang-Hoi; Park, Hoonyoung; Piao, Shilong; Kim, Jinwon; Feng, Song

    2017-09-01

    Understanding changes in background dryness over land is key information for adapting to climate change because of its critical socioeconomic consequences. However, causes of continental dryness changes remain uncertain because various climate parameters control dryness. Here, we verify dominant climate variables determining dryness trends over continental eastern Asia, which is characterized by diverse hydroclimate regimes ranging from arid to humid, by quantifying the relative effects of changes in precipitation, solar radiation, wind speed, surface air temperature, and relative humidity on trends in the aridity index based on observed data from 189 weather stations for the period of 1961-2010. Before the early 1980s (1961-1983), change in precipitation is a primary condition for determining aridity trends. In the later period (1984-2010), the dominant climate parameter for aridity trends varies according to the hydroclimate regime. Drying trends in arid regions are mostly explained by reduced precipitation. In contrast, the increase in potential evapotranspiration due to increased atmospheric water-holding capacity, a secondary impact of warming, works to increase aridity over the humid monsoon region despite an enhanced water supply and relatively less warming. Our results show significant drying effects of warming over the humid monsoon region in recent decades; this also supports the drying trends over warm and water-sufficient regions in future climate.

  9. Dominance of climate warming effects on recent drying trends over wet monsoon regions

    Directory of Open Access Journals (Sweden)

    C.-E. Park

    2017-09-01

    Full Text Available Understanding changes in background dryness over land is key information for adapting to climate change because of its critical socioeconomic consequences. However, causes of continental dryness changes remain uncertain because various climate parameters control dryness. Here, we verify dominant climate variables determining dryness trends over continental eastern Asia, which is characterized by diverse hydroclimate regimes ranging from arid to humid, by quantifying the relative effects of changes in precipitation, solar radiation, wind speed, surface air temperature, and relative humidity on trends in the aridity index based on observed data from 189 weather stations for the period of 1961–2010. Before the early 1980s (1961–1983, change in precipitation is a primary condition for determining aridity trends. In the later period (1984–2010, the dominant climate parameter for aridity trends varies according to the hydroclimate regime. Drying trends in arid regions are mostly explained by reduced precipitation. In contrast, the increase in potential evapotranspiration due to increased atmospheric water-holding capacity, a secondary impact of warming, works to increase aridity over the humid monsoon region despite an enhanced water supply and relatively less warming. Our results show significant drying effects of warming over the humid monsoon region in recent decades; this also supports the drying trends over warm and water-sufficient regions in future climate.

  10. Prominent Midlatitude Circulation Signature in High Asia's Surface Climate During Monsoon

    Science.gov (United States)

    Mölg, Thomas; Maussion, Fabien; Collier, Emily; Chiang, John C. H.; Scherer, Dieter

    2017-12-01

    High Asia has experienced strong environmental changes in recent decades, as evident in records of glaciers, lakes, tree rings, and vegetation. The multiscale understanding of the climatic drivers, however, is still incomplete. In particular, few systematic assessments have evaluated to what degree, if at all, the midlatitude westerly circulation modifies local surface climates in the reach of the Indian Summer Monsoon. This paper shows that a southward shift of the upper-tropospheric westerlies contributes significantly to climate variability in the core monsoon season (July-September) by two prominent dipole patterns at the surface: cooling in the west of High Asia contrasts with warming in the east, while moist anomalies in the east and northwest occur with drying along the southwestern margins. Circulation anomalies help to understand the dipoles and coincide with shifts in both the westerly wave train and the South Asian High, which imprint on air mass advection and local energy budgets. The relation of the variabilities to a well-established index of midlatitude climate dynamics allows future research on climate proxies to include a fresh hypothesis for the interpretation of environmental changes.

  11. On the climate model simulation of Indian monsoon low pressure systems and the effect of remote disturbances and systematic biases

    Science.gov (United States)

    Levine, Richard C.; Martin, Gill M.

    2018-06-01

    Monsoon low pressure systems (LPS) are synoptic-scale systems forming over the Indian monsoon trough region, contributing substantially to seasonal mean summer monsoon rainfall there. Many current global climate models (GCMs), including the Met Office Unified Model (MetUM), show deficient rainfall in this region, much of which has previously been attributed to remote systematic biases such as excessive equatorial Indian Ocean (EIO) convection, while also substantially under-representing LPS and associated rainfall as they travel westwards across India. Here the sources and sensitivities of LPS to local, remote and short-timescale forcing are examined, in order to understand the poor representation in GCMs. An LPS tracking method is presented using TRACK feature tracking software for comparison between re-analysis data-sets, MetUM GCM and regional climate model (RCM) simulations. RCM simulations, at similar horizontal resolution to the GCM and forced with re-analysis data at the lateral boundaries, are carried out with different domains to examine the effects of remote biases. The results suggest that remote biases contribute significantly to the poor simulation of LPS in the GCM. As these remote systematic biases are common amongst many current GCMs, it is likely that GCMs are intrinsically capable of representing LPS, even at relatively low resolution. The main problem areas are time-mean excessive EIO convection and poor representation of precursor disturbances transmitted from the Western Pacific. The important contribution of the latter is established using RCM simulations forced by climatological 6-hourly lateral boundary conditions, which also highlight the role of LPS in moving rainfall from steep orography towards Central India.

  12. Aerosol-Water Cycle Interaction: A New Challenge in Monsoon Climate Research

    Science.gov (United States)

    Lau, William K. M.

    2006-01-01

    Long recognized as a major environmental hazard, aerosol is now known to have strong impacts on both regional and global climate. It has been estimated that aerosol may reduce by up to 10% of the seasonal mean solar radiation reaching the earth surface, producing a global cooling effect that opposes global warming (Climate Change 2001). This means that the potential perils that humans have committed to global warming may be far greater than what we can detect at the present. As a key component of the Earth climate system, the water cycle is profoundly affected by the presence of aerosols in the atmosphere. Through the so-called "direct effect", aerosol scatters and/or absorbs solar radiation, thus cooling the earth surface and changing the horizontal and vertical radiational heating contrast in the atmosphere. The heating contrast drives anomalous atmospheric circulation, resulting in changes in convection, clouds, and rainfall. Another way aerosol can affect the water cycle is through the so-called "indirect effects", whereby aerosol increases the number of cloud condensation nuclei, prolongs life time of clouds, and inhibits the growth of cloud drops to raindrops. This leads to more clouds, and increased reflection of solar radiation, and further cooling at the earth surface. In monsoon regions, the response of the water cycle to aerosol forcing is especially complex, not only because of presence of diverse mix of aerosol species with vastly different radiative properties, but also because the monsoon is strongly influenced by ocean and land surface processes, land use, land change, as well as regional and global greenhouse warming effects. Thus, sorting out the impacts of aerosol forcing, and interaction with the monsoon water cycle is a very challenging problem. In this talk, I will offer some insights into how aerosols may impact the Asian monsoon based on preliminary results from satellite observations and climate model experiments. Specifically, I will

  13. Late Holocene monsoon climate as evidenced by proxy records from a lacustrine sediment sequence in western Guangdong, South China

    Science.gov (United States)

    Zhong, Wei; Cao, jiayuan; Xue, Jibin; Ouyang, Jun; Tang, Xiaohong; Yin, Huanling; Liao, Congyun; Long, Kun

    2014-02-01

    The study of a 300-cm-thick exposed lacustrine sediment section in the Hedong village in Zhaoqing area which is located in sub-tropical west Guangdong Province in South China, demonstrates that the lacustrine sedimentary sequence possibly contains evidence for exploring variation of Asian monsoon climate. Multi-proxy records, including the humification intensity, total organic carbon, and grain size fractions, reveal a general trend towards dry and cold conditions in the late Holocene that this is because of a decrease in solar insolation on an orbital scale. Three intensified Asian summer monsoon (ASM) intervals (˜3300-3000 cal yr BP, ˜2600-1600 cal yr BP, and ˜900-600 cal yr BP), and three weakened ASM intervals (˜4000-3300 cal yr BP, ˜3000-2600 cal yr BP, and ˜1600-900 cal yr BP) are identified. Our humification record (HDcal) shows a good correlation on multi-centennial scale with the tree ring Δ14C record, a proxy of solar activity. A spectral analysis of HDcal reveals four significant cycles, i.e., ˜1250 yr, 300 yr, 110 yr, and 70 yr, and most of these cycles are related to the solar activity. Our findings indicate that solar output and oceanic-atmospheric circulation probably have influenced the late Holocene climate variability in the study region.

  14. Future projections of active-break spells of Indian summer monsoon in a climate change perspective

    Science.gov (United States)

    Sudeepkumar, B. L.; Babu, C. A.; Varikoden, Hamza

    2018-02-01

    The effect of global climate change on Indian summer monsoon has been analysed with special emphasis on active-break cycle. The changes in intensity and duration of active and break monsoon conditions towards the end of the century are studied by using 850 hPa zonal circulations. The analysis is carried out using twenty year climatology of historical period (1986-2005) and future projections (2080-2099) simulated as part of Coupled Model Intercomparison Project phase 5 (CMIP5). Models are compared with NCEP/NCAR reanalysis data. The models that effectively capture the circulation pattern of monsoon (JJAS) are considered for assessing the future climate in RCP 4.5 scenario. They are CanESM2, CNRM-CM5, GFDL-ESM2M, MIROC5 and MPI-ESM-LR. During the southwest monsoon period, the ensemble mean of models projects a strengthening of the wind speed towards north (north of 15°N) and weakening to the southern region (especially south of 12°N) which facilitates wetting of northern Indian regions and drying of southern peninsular regions. In the case of active-break conditions, the active spells are found to be strengthening over northern India and weakening over the peninsular India, the break spells intensify over southern tip of peninsular India indicating intense breaks. Increased propensity of short intense active days and decreased propensity of long active days are also projected by the models. The number of break spells does not show any significant changes.

  15. Holocene climatic fluctuations and periodic changes in the Asian southwest monsoon region

    Science.gov (United States)

    Zhang, Wenxiang; Niu, Jie; Ming, Qingzhong; Shi, Zhengtao; Lei, Guoliang; Huang, Linpei; Long, Xian'e.; Chang, Fengqin

    2018-05-01

    Climatic changes in the Asian southwest monsoon (ASWM) during the Holocene have become a topic of recent studies. It is important to understand the patterns and causes of Holocene climatic changes and their relationship with global changes. Based on the climate proxies and wavelet analysis of Lugu Lake in the ASWM region, the climatic fluctuations and periodic changes in the ASWM region during the Holocene have been reconstructed with a high-precision chronology. The results indicate the intensification of ASWM began to increase with Northern Hemisphere low-latitude solar insolation (LSI) and solar activity during the early Holocene, and gradually decreased during the late Holocene, exhibiting an apparent synchrony with numerous records of ASWM region. Meanwhile, an apparent 1000-a quasi-periodic signal is present in the environment proxies, and it demonstrates that the environmental change in the ASWM region has been driven mainly by LSI and solar activity.

  16. Trends and variations of pH and hardness in a typical semi-arid river in a monsoon climate region during 1985-2009.

    Science.gov (United States)

    Hao, Shaonan; Li, Xuyong; Jiang, Yan; Zhao, Hongtao; Yang, Lei

    2016-09-01

    The rapid growth of urbanization and industrialization, along with dramatic climate change, has strongly influenced hydrochemical characteristics in recent decades in China and thus could cause the variation of pH and general total hardness of a river. To explore such variations and their potential influencing factors in a river of the monsoon climate region, we analyzed a long-term monitoring dataset of pH, SO4 (2-), NOx, general total hardness (GH), Mg(2+), Ca(2+), and Cl(-) in surface water and groundwater in the Luan River basin from 1985 to 2009. The nonparametric Seasonal Kendall trend test was used to test the long-term trends of pH and GH. Relationship between the affecting factors, pH and GH were discussed. Results showed that pH showed a decreasing trend and that GH had an increasing trend in the long-term. Seasonal variation of pH and GH was mainly due to the typical monsoon climate. Results of correlation analysis showed that the unit area usage amounts of chemical fertilizer, NO3 (-), and SO4 (2-) were negatively correlated with pH in groundwater. In addition, mining activity affected GH spatial variation. Acid deposition, drought, and increasing the use of chemical fertilizers would contribute to the acidification trend, and mining activities would affect the spatial variation of GH. Variations of precipitation and runoff in semi-arid monsoon climate areas had significant influences on the pH and GH. Our findings implied that human activities played a critical role in river acidification in the semi-arid monsoon climate region of northern China.

  17. Role of aerosols on the Indian Summer Monsoon variability, as simulated by state-of-the-art global climate models

    Science.gov (United States)

    Cagnazzo, Chiara; Biondi, Riccardo; D'Errico, Miriam; Cherchi, Annalisa; Fierli, Federico; Lau, William K. M.

    2016-04-01

    Recent observational and modeling analyses have explored the interaction between aerosols and the Indian summer monsoon precipitation on seasonal-to-interannual time scales. By using global scale climate model simulations, we show that when increased aerosol loading is found on the Himalayas slopes in the premonsoon period (April-May), intensification of early monsoon rainfall over India and increased low-level westerly flow follow, in agreement with the elevated-heat-pump (EHP) mechanism. The increase in rainfall during the early monsoon season has a cooling effect on the land surface that may also be amplified through solar dimming (SD) by more cloudiness and aerosol loading with subsequent reduction in monsoon rainfall over India. We extend this analyses to a subset of CMIP5 climate model simulations. Our results suggest that 1) absorbing aerosols, by influencing the seasonal variability of the Indian summer monsoon with the discussed time-lag, may act as a source of predictability for the Indian Summer Monsoon and 2) if the EHP and SD effects are operating also in a number of state-of-the-art climate models, their inclusion could potentially improve seasonal forecasts.

  18. Performance of Regional Climate Model in Simulating Monsoon Onset Over Indian Subcontinent

    Science.gov (United States)

    Bhatla, R.; Mandal, B.; Verma, Shruti; Ghosh, Soumik; Mall, R. K.

    2018-06-01

    The performance of various Convective Parameterization Schemes (CPSs) of Regional Climate Model version 4.3 (RegCM-4.3) for simulation of onset phase of Indian summer monsoon (ISM) over Kerala was studied for the period of 2001-2010. The onset date and its associated spatial variation were simulated using RegCM-4.3 four core CPS, namely Kuo, Tiedtke, Emanuel and Grell; and with two mixed convection schemes Mix98 (Emanuel over land and Grell over ocean) and Mix99 (Grell over land and Emanuel over ocean) on the basis of criteria given by the India Meteorological Department (IMD) (Pai and Rajeevan in Indian summer monsoon onset: variability and prediction. National Climate Centre, India Meteorological Department, 2007). It has been found that out of six CPS, two schemes, namely Tiedtke and Mix99 simulated the onset date properly. The onset phase is characterized with several transition phases of atmosphere. Therefore, to study the thermal response or the effect of different sea surface temperature (SST), namely ERA interim (ERSST) and weekly optimal interpolation (OI_WK SST) on Indian summer monsoon, the role of two different types of SST has been used to investigate the simulated onset date. In addition, spatial atmospheric circulation pattern during onset phase were analyzed using reanalyze dataset of ERA Interim (EIN15) and National Oceanic and Atmospheric Administration (NOAA), respectively, for wind and outgoing long-wave radiation (OLR) pattern. Among the six convective schemes of RegCM-4.3 model, Tiedtke is in good agreement with actual onset dates and OI_WK SST forcing is better for simulating onset of ISM over Kerala.

  19. Prediction of summer monsoon rainfall over India using the NCEP climate forecast system

    Energy Technology Data Exchange (ETDEWEB)

    Pattanaik, D.R. [India Meteorological Department (IMD), New Delhi (India); Kumar, Arun [Climate Prediction Center, National Centre for Environmental Prediction (NCEP)/NWS/NOAA, Camp Springs, MD (United States)

    2010-03-15

    The performance of a dynamical seasonal forecast system is evaluated for the prediction of summer monsoon rainfall over the Indian region during June to September (JJAS). The evaluation is based on the National Centre for Environmental Prediction's (NCEP) climate forecast system (CFS) initialized during March, April and May and integrated for a period of 9 months with a 15 ensemble members for 25 years period from 1981 to 2005. The CFS's hindcast climatology during JJAS of March (lag-3), April (lag-2) and May (lag-1) initial conditions show mostly an identical pattern of rainfall similar to that of verification climatology with the rainfall maxima (one over the west-coast of India and the other over the head Bay of Bengal region) well simulated. The pattern correlation between verification and forecast climatology over the global tropics and Indian monsoon region (IMR) bounded by 50 E-110 E and 10 S-35 N shows significant correlation coefficient (CCs). The skill of simulation of broad scale monsoon circulation index (Webster and Yang; WY index) is quite good in the CFS with highly significant CC between the observed and predicted by the CFS from the March, April and May forecasts. High skill in forecasting El Nino event is also noted for the CFS March, April and May initial conditions, whereas, the skill of the simulation of Indian Ocean Dipole is poor and is basically due to the poor skill of prediction of sea surface temperature (SST) anomalies over the eastern equatorial Indian Ocean. Over the IMR the skill of monsoon rainfall forecast during JJAS as measured by the spatial Anomaly CC between forecast rainfall anomaly and the observed rainfall anomaly during 1991, 1994, 1997 and 1998 is high (almost of the order of 0.6), whereas, during the year 1982, 1984, 1985, 1987 and 1989 the ACC is only around 0.3. By using lower and upper tropospheric forecast winds during JJAS over the regions of significant CCs as predictors for the All India Summer Monsoon

  20. Decline and poleward shift in Indian summer monsoon synoptic activity in a warming climate

    Science.gov (United States)

    Sandeep, S.; Ajayamohan, R. S.; Boos, William R.; Sabin, T. P.; Praveen, V.

    2018-03-01

    Cyclonic atmospheric vortices of varying intensity, collectively known as low-pressure systems (LPS), travel northwest across central India and produce more than half of the precipitation received by that fertile region and its ˜600 million inhabitants. Yet, future changes in LPS activity are poorly understood, due in part to inadequate representation of these storms in current climate models. Using a high-resolution atmospheric general circulation model that realistically simulates the genesis distribution of LPS, here we show that Indian monsoon LPS activity declines about 45% by the late 21st century in simulations of a business-as-usual emission scenario. The distribution of LPS genesis shifts poleward as it weakens, with oceanic genesis decreasing by ˜60% and continental genesis increasing by ˜10%; over land the increase in storm counts is accompanied by a shift toward lower storm wind speeds. The weakening and poleward shift of the genesis distribution in a warmer climate are confirmed and attributed, via a statistical model, to the reduction and poleward shift of low-level absolute vorticity over the monsoon region, which in turn are robust features of most coupled model projections. The poleward shift in LPS activity results in an increased frequency of extreme precipitation events over northern India.

  1. Simulation skill of APCC set of global climate models for Asian summer monsoon rainfall variability

    Science.gov (United States)

    Singh, U. K.; Singh, G. P.; Singh, Vikas

    2015-04-01

    The performance of 11 Asia-Pacific Economic Cooperation Climate Center (APCC) global climate models (coupled and uncoupled both) in simulating the seasonal summer (June-August) monsoon rainfall variability over Asia (especially over India and East Asia) has been evaluated in detail using hind-cast data (3 months advance) generated from APCC which provides the regional climate information product services based on multi-model ensemble dynamical seasonal prediction systems. The skill of each global climate model over Asia was tested separately in detail for the period of 21 years (1983-2003), and simulated Asian summer monsoon rainfall (ASMR) has been verified using various statistical measures for Indian and East Asian land masses separately. The analysis found a large variation in spatial ASMR simulated with uncoupled model compared to coupled models (like Predictive Ocean Atmosphere Model for Australia, National Centers for Environmental Prediction and Japan Meteorological Agency). The simulated ASMR in coupled model was closer to Climate Prediction Centre Merged Analysis of Precipitation (CMAP) compared to uncoupled models although the amount of ASMR was underestimated in both models. Analysis also found a high spread in simulated ASMR among the ensemble members (suggesting that the model's performance is highly dependent on its initial conditions). The correlation analysis between sea surface temperature (SST) and ASMR shows that that the coupled models are strongly associated with ASMR compared to the uncoupled models (suggesting that air-sea interaction is well cared in coupled models). The analysis of rainfall using various statistical measures suggests that the multi-model ensemble (MME) performed better compared to individual model and also separate study indicate that Indian and East Asian land masses are more useful compared to Asia monsoon rainfall as a whole. The results of various statistical measures like skill of multi-model ensemble, large spread

  2. SST and OLR relationship during Indian summer monsoon: a coupled climate modelling perspective

    Science.gov (United States)

    Chaudhari, Hemantkumar S.; Hazra, Anupam; Pokhrel, Samir; Chakrabarty, Chandrima; Saha, Subodh Kumar; Sreenivas, P.

    2018-04-01

    The study mainly investigates sea surface temperature (SST) and outgoing longwave radiation (OLR) relationships in coupled climate model. To support the analysis, high-level cloud and OLR relationship is also investigated. High-level cloud and OLR relationship depicts significant negative correlation over the entire monsoon regime. Coupled climate model is able to produce the same. SST and OLR relationship in observation also depicts significant negative relationship, in particular, over the Equatorial Eastern Indian Ocean (EIO) region. Climate Forecast System version 2 (CFSv2) is able to portray the negative relationship over EIO region; however, it is underestimated as compared to observation. Significant negative correlations elucidate that local SSTs regulate the convection and further it initiates Bjerknes feedback in the central Indian Ocean. It connotes that SST anomalies during monsoon period tend to be determined by oceanic forcing. The heat content of the coastal Bay of Bengal shows highest response to EIO SST by a lag of 1 month. It suggests that the coastal region of the Bay of Bengal is marked by coastally trapped Kelvin waves, which might have come from EIO at a time lag of 1 month. Sea surface height anomalies, depth at 20 °C isotherms and depth at 26 isotherms also supports the above hypothesis. Composite analysis based on EIO index and coupled climate model sensitivity experiments also suggest that the coastal Bay of Bengal region is marked by coastally trapped Kelvin waves, which are propagated from EIO at a time lag of 1 month. Thus, SST and OLR relationship pinpoints that the Bay of Bengal OLR (convection) is governed by local ocean-atmospheric coupling, which is influenced by the delayed response from EIO brought forward through oceanic planetary waves at a lag of 1 month. These results have utmost predictive value for seasonal and extended range forecasting. Thus, OLR and SST relationship can constitute a pivotal role in investigating the

  3. The Asian-Australian Monsoon and El Niño-Southern Oscillation in the NCAR Climate System Model*.

    Science.gov (United States)

    Meehl, Gerald A.; Arblaster, Julie M.

    1998-06-01

    Features associated with the Asian-Australian monsoon system and El Niño-Southern Oscillation (ENSO) are described in the National Center for Atmospheric Research (NCAR) global coupled Climate System Model (CSM). Simulation characteristics are compared with a version of the atmospheric component of the CSM, the NCAR CCM3, run with time-evolving SSTs from 1950 to 1994, and with observations. The CSM is shown to represent most major features of the monsoon system in terms of mean climatology, interannual variability, and connections to the tropical Pacific. This includes a representation of the Southern Oscillation links between strong Asian-Australian monsoons and associated negative SST anomalies in the eastern equatorial Pacific. The equatorial SST gradient across the Pacific in the CSM is shown to be similar to the observed with somewhat cooler mean SSTs across the entire Pacific by about 1°-2°C. The seasonal cycle of SSTs in the eastern equatorial Pacific has the characteristic signature seen in the observations of relatively warmer SSTs propagating westward in the first half of the year followed by the reestablishment of the cold tongue with relatively colder SSTs propagating westward in the second half of the year. Like other global coupled models, the propagation is similar to the observed but with the establishment of the relatively warmer water in the first half of the year occurring about 1-2 months later than observed. The seasonal cycle of precipitation in the tropical eastern Pacific is also similar to other global coupled models in that there is a tendency for a stronger-than-observed double ITCZ year round, particularly in northern spring, but with a well-reproduced annual maximum of ITCZ strength north of the equator in the second half of the year. Time series of area-averaged SSTs for the NINO3 region in the eastern equatorial Pacific show that the CSM is producing about 60% of the amplitude of the observed variability in that region, consistent

  4. Prediction of Monthly Summer Monsoon Rainfall Using Global Climate Models Through Artificial Neural Network Technique

    Science.gov (United States)

    Nair, Archana; Singh, Gurjeet; Mohanty, U. C.

    2018-01-01

    The monthly prediction of summer monsoon rainfall is very challenging because of its complex and chaotic nature. In this study, a non-linear technique known as Artificial Neural Network (ANN) has been employed on the outputs of Global Climate Models (GCMs) to bring out the vagaries inherent in monthly rainfall prediction. The GCMs that are considered in the study are from the International Research Institute (IRI) (2-tier CCM3v6) and the National Centre for Environmental Prediction (Coupled-CFSv2). The ANN technique is applied on different ensemble members of the individual GCMs to obtain monthly scale prediction over India as a whole and over its spatial grid points. In the present study, a double-cross-validation and simple randomization technique was used to avoid the over-fitting during training process of the ANN model. The performance of the ANN-predicted rainfall from GCMs is judged by analysing the absolute error, box plots, percentile and difference in linear error in probability space. Results suggest that there is significant improvement in prediction skill of these GCMs after applying the ANN technique. The performance analysis reveals that the ANN model is able to capture the year to year variations in monsoon months with fairly good accuracy in extreme years as well. ANN model is also able to simulate the correct signs of rainfall anomalies over different spatial points of the Indian domain.

  5. North American Monsoon Response to Eemian Climate Forcings and its Effect on Rocky Mountain Forests

    Science.gov (United States)

    Insel, N.; Berkelhammer, M. B.

    2017-12-01

    The key to recognizing and predicting future changes in regional climate and ecosystems lies in understanding the causes and characteristics of paleovariations. The Last Interglacial (LIG: 130-116 ka) is the most recent period in Earth history when temperatures are believed to have exceeded those of today. In this study, we are focusing on the response of the North American monsoon (NAM) to shifts in orbital forcings during LIG. In particular, we are using regional climate model (RegCM) simulations under LIG (115ka, 125 ka and 135 ka) and modern forcings to evaluate changes in the strength, timing, duration, and amount of moisture transported from different sources during the NAM season. Understanding these variations is critical to forecast seasonal supply of water to the southwestern U.S. under current warming conditions. In addition, cellulose extracted stable isotopes from Rocky Mountain Eemian wood samples provides both a tool to diagnose the model simulations and to evaluate the response of western U.S. tree species to changes in temperature and moisture availability. Our preliminary results indicate enhanced summer precipitation, wind shifts and changes in NAM characteristics in response to increased Northern Hemisphere insolation. The following features were observed: (1) The NAM strengthens and extends slightly more northward during the Eemian due to a shift in upper-level divergence. (2) The onset and duration of the NAM seems to be similar between modern and Eemian simulations. (3) Consistent with modern observations, simulations suggest a western NAM region in Arizona that receives most of its monsoonal moisture from the Gulf of California, while the eastern NAM region in New Mexico obtains most of its summer rains from the Gulf of Mexico. In the Eemian, we see a spatial shift from more depleted to more enriched source waters throughout the monsoon season. These changes in the summer climate are confirmed by the tree ring isotope data, which show a

  6. quantitative precipitation forecasts during the Indian Summer Monsoon

    Indian Academy of Sciences (India)

    65

    the Indian Summer Monsoon: Contiguous Rain Area (CRA) Approach ... 1Centre for Australian Weather and Climate Research, Melbourne, Australia ... are evaluated over India using the Contiguous Rainfall Area (CRA) verification technique.

  7. Divergent influences of the Greenland and Antarctica climates on the Asian monsoon during a stadial to interstadial cycle

    Science.gov (United States)

    Duan, Fucai; Wang, Yongjin; Liao, Zebo; Chen, Shitao; Zhang, Weihong; Shao, Qingfeng

    2018-06-01

    Despite the links of Asian monsoon with climates at high northern and southern latitudes, it remains unclear that at which time and to what extent the Asian monsoon variation is dominated by one of the two drivers throughout a Greenland Stadial (GS) to Greenland Interstadial (GI) cycle. Here we provide a Chinese stalagmite δ18O record to study their teleconnections throughout the GS-6 to GI-5.2 cycle. The resemblance between the stalagmite and Greenland records, in timing, duration and abruptness of GI-5.2, supports that the occurrence and termination of GIs are paced by the northern driving force. During the intervals of GI-5.2 and GS-6, however, the Asian monsoon fluctuated concomitantly with variation in temperature over Antarctica, instead of over Greenland. This covariation indicates dominant influences of the Antarctic climate during the climatically stable intervals of stadials and interstadials. This study updates our knowledge on mechanical dynamics of the Asian monsoon change and global climate change throughout a GS to GI cycle.

  8. Representation of the West African Monsoon System in the aerosol-climate model ECHAM6-HAM2

    Science.gov (United States)

    Stanelle, Tanja; Lohmann, Ulrike; Bey, Isabelle

    2017-04-01

    The West African Monsoon (WAM) is a major component of the global monsoon system. The temperature contrast between the Saharan land surface in the North and the sea surface temperature in the South dominates the WAM formation. The West African region receives most of its precipitation during the monsoon season between end of June and September. Therefore the existence of the monsoon is of major social and economic importance. We discuss the ability of the climate model ECHAM6 as well as the coupled aerosol climate model ECHAM6-HAM2 to simulate the major features of the WAM system. The north-south temperature gradient is reproduced by both model versions but all model versions fail in reproducing the precipitation amount south of 10° N. A special focus is on the representation of the nocturnal low level jet (NLLJ) and the corresponding enhancement of low level clouds (LLC) at the Guinea Coast, which are a crucial factor for the regional energy budget. Most global climate models have difficulties to represent these features. The pure climate model ECHAM6 is able to simulate the existence of the NLLJ and LLC, but the model does not represent the pronounced diurnal cycle. Overall, the representation of LLC is worse in the coupled model. We discuss the model behaviors on the basis of outputted temperature and humidity tendencies and try to identify potential processes responsible for the model deficiencies.

  9. The representation of low-level clouds during the West African monsoon in weather and climate models

    Science.gov (United States)

    Kniffka, Anke; Hannak, Lisa; Knippertz, Peter; Fink, Andreas

    2016-04-01

    The West African monsoon is one of the most important large-scale circulation features in the tropics and the associated seasonal rainfalls are crucial to rain-fed agriculture and water resources for hundreds of millions of people. However, numerical weather and climate models still struggle to realistically represent salient features of the monsoon across a wide range of scales. Recently it has been shown that substantial errors in radiation and clouds exist in the southern parts of West Africa (8°W-8°E, 5-10°N) during summer. This area is characterised by strong low-level jets associated with the formation of extensive ultra-low stratus clouds. Often persisting long after sunrise, these clouds have a substantial impact on the radiation budget at the surface and thus the diurnal evolution of the planetary boundary layer (PBL). Here we present some first results from a detailed analysis of the representation of these clouds and the associated PBL features across a range of weather and climate models. Recent climate model simulations for the period 1991-2010 run in the framework of the Year of Tropical Convection (YOTC) offer a great opportunity for this analysis. The models are those used for the latest Assessment Report of the Intergovernmental Panel on Climate Change, but for YOTC the model output has a much better temporal resolution, allowing to resolve the diurnal cycle, and includes diabatic terms, allowing to much better assess physical reasons for errors in low-level temperature, moisture and thus cloudiness. These more statistical climate model analyses are complemented by experiments using ICON (Icosahedral non-hydrostatic general circulation model), the new numerical weather prediction model of the German Weather Service and the Max Planck Institute for Meteorology. ICON allows testing sensitivities to model resolution and numerical schemes. These model simulations are validated against (re-)analysis data, satellite observations (e.g. CM SAF cloud and

  10. Equilibrium climate response of the East Asian summer monsoon to forcing of anthropogenic aerosol species

    Science.gov (United States)

    Wang, Zhili; Wang, Qiuyan; Zhang, Hua

    2017-12-01

    We used an online aerosol-climate model to study the equilibrium climate response of the East Asian summer monsoon (EASM) to increases in anthropogenic emissions of sulfate, organic carbon, and black carbon aerosols from 1850 to 2000. Our results show that each of these aerosol species has a different effect on the EASM as a result of changes in the local sea-land thermal contrast and atmospheric circulation. The increased emission of sulfate aerosol leads to a decrease in the thermal contrast between the land and ocean, a southward shift of the East Asian subtropical jet, and significant northerly wind anomalies at 850 hPa over eastern China and the ambient oceans, markedly dampening the EASM. An increase in organic carbon aerosol results in pronounced surface cooling and the formation of an anomalous anticyclone over the oceans north of 30°N. These effects cause a slight increase in the sea-land thermal contrast and southerly flow anomalies to the west of the anticyclonic center, strengthening the northern EASM. An increase in organic carbon emission decreases the sea-land thermal contrast over southern China, which weakens the southern EASM. The response of the summer 850-hPa winds and rainfall over the East Asian monsoon region to an increase in black carbon emission is generally consistent with the response to an increase in organic carbon. The increase in black carbon emission leads to a strengthening of the northern EASM north of 35°N and a slight weakening of the southern EASM south of 35°N. The simulated response of the EASM to the increase in black carbon emission is unchanged when the emission of black carbon is scaled up by five times its year 2000 levels, although the intensities of the response is enhanced. The increase in sulfate emission primarily weakens the EASM, whereas the increases in black carbon and organic carbon emissions mitigate weakening of the northern EASM.

  11. Characterization and source identification of nitrogen in a riverine system of monsoon-climate region, China.

    Science.gov (United States)

    Yuan, Jie; Li, Siyue; Han, Xi; Chen, Qiuyang; Cheng, Xiaoli; Zhang, Quanfa

    2017-08-15

    There are increasing concerns in nitrogen (N) pollution worldwide, especially in aquatic ecosystems, and thus quantifying its sources in waterways is critical for pollution prevention and control. In this study, we investigated the spatio-temporal variabilities of inorganic N concentration (i.e., NO 3 - , NH 4 + ) and total dissolved N (TDN) and identified their sources in waters and suspended matters using an isotopical approach in the Jinshui River, a river with a length of 87km in the monsoon-climate region of China. The spatio-temporal inorganic N concentrations differed significantly along the longitudinal gradient in the river network. The NO 3 - , NH 4 + and TDN concentrations ranged from 0.02 to 1.12mgl -1 , 0.03 to 4.28mgl -1 , and 0.33 to 2.78mgl -1 , respectively. The 15 N tracing studies demonstrated that N in suspended organic matter was in the form of suspended particulate nitrogen (SPN) and was primarily from atmospheric deposition and agricultural fertilizer. In contrast, N in stream waters was mainly in the form of nitrate and was from atmospheric deposition, fertilizers, soil, and sewage. Meanwhile, both δ 15 N-SPN and δ 15 N-NO 3 - peaked in the rainy season (i.e., July) because of higher terrigenous sources via rain runoff, demonstrating the dominant diffusive N sources in the catchment. Thus, our results could provide critical information on N pollution control and sustainable watershed management of the riverine ecosystem in monsoon-climate region. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. The 9.2 ka event in Asian summer monsoon area: the strongest millennial scale collapse of the monsoon during the Holocene

    Science.gov (United States)

    Zhang, Wenchao; Yan, Hong; Dodson, John; Cheng, Peng; Liu, Chengcheng; Li, Jianyong; Lu, Fengyan; Zhou, Weijian; An, Zhisheng

    2018-04-01

    Numerous Holocene paleo-proxy records exhibit a series of centennial-millennial scale rapid climatic events. Unlike the widely acknowledged 8.2 ka climate anomaly, the likelihood of a significant climate excursion at around 9.2 cal ka BP, which has been notably recognized in some studies, remains to be fully clarified in terms of its magnitude and intensity, as well as its characteristics and spatial distributions in a range of paleoclimatic records. In this study, a peat sediment profile from the Dajiuhu Basin in central China was collected with several geochemical proxies and a pollen analysis carried out to help improve understanding of the climate changes around 9.2 cal ka BP. The results show that the peat development was interrupted abruptly at around 9.2 cal ka BP, when the chemical weathering strength decreased and the tree-pollen declined. This suggests that a strong drier regional climatic event occurred at around 9.2 cal ka BP in central China, which was, in turn, probably connected to the rapid 9.2 ka climate event co-developing worldwide. In addition, based on the synthesis of our peat records and the other Holocene hydrological records from Asian summer monsoon (ASM) region, we further found that the 9.2 ka event probably constituted the strongest abrupt collapse of the Asian monsoon system during the full Holocene interval. The correlations between ASM and the atmospheric 14C production rate, the North Atlantic drift ice records and Greenland temperature indicated that the weakened ASM event at around 9.2 cal ka BP could be interpreted by the co-influence of external and internal factors, related to the changes of the solar activity and the Atlantic Meridional Overturning Circulation (AMOC).

  13. Emergent properties of climate-vegetation feedbacks in the North American Monsoon Macrosystem

    Science.gov (United States)

    Mathias, A.; Niu, G.; Zeng, X.

    2012-12-01

    The ability of ecosystems to adapt naturally to climate change and associated disturbances (e.g. wildfires, spread of invasive species) is greatly affected by the stability of feedback interactions between climate and vegetation. In order to study climate-vegetation interactions, such as CO2 and H2O exchange in the North American Monsoon System (NAMS), we plan to couple a community land surface model (NoahMP or CLM) used in regional climate models (WRF) with an individual based, spatially explicit vegetation model (ECOTONE). Individual based modeling makes it possible to link individual plant traits with properties of plant communities. Community properties, such as species composition and species distribution arise from dynamic interactions of individual plants with each other, and with their environment. Plants interact with each other through intra- and interspecific competition for resources (H2O, nitrogen), and the outcome of these interactions depends on the properties of the plant community and the environment itself. In turn, the environment is affected by the resulting change in community structure, which may have an impact on the drivers of climate change. First, we performed sensitivity tests of ECOTONE to assess its ability to reproduce vegetation distribution in the NAMS. We compared the land surface model and ECOTONE with regard to their capability to accurately simulate soil moisture, CO2 flux and above ground biomass. For evaluating the models we used the eddy-correlation sensible and latent heat fluxes, CO2 flux and observations of other climate and environmental variables (e.g. soil temperature and moisture) from the Santa Rita experimental range. The model intercomparison helped us understand the advantages and disadvantages of each model, providing us guidance for coupling the community land surface model (NoahMP or CLM) with ECOTONE.

  14. Predicting Monsoonal-Driven Stream Discharge and Sediment Yield in Himalaya Mountain Basins with Changing Climate and Deforestation

    Science.gov (United States)

    Neupane, R. P.; White, J. D.

    2014-12-01

    Short and long term effects of site water availability impacts the spectrum of management outcomes including landslide risk, hydropower generation, and sustainable agriculture in mountain systems heavily influenced by climate and land use changes. Climate change and land use may predominantly affect the hydrologic cycle of mountain basins as soil precipitation interception is affected by land cover. Using the Soil and Water Assessment Tool, we estimated stream discharge and sediment yield associated with climate and land use changes for two Himalaya basins located at eastern and western margins of Nepal that included drainages of the Tamor and Seti Rivers. Future climate change was modeled using average output of temperature and precipitation changes derived from Special Report on Emission Scenarios (B1, A1B & A2) of 16 global circulation models for 2080 as meteorological inputs into SWAT. Land use change was modeled spatially and included 1) deforestation, 2) expansion of agricultural land, and 3) increased human settlement that were produced by considering current land use with projected changes associated with viability of elevation and slope characteristics of the basins capable of supporting different land use types. We found higher annual stream discharge in all GCM-derived scenarios compared to the baseline with maximum increases of 13 and 8% in SRES-A2 and SRES-A1B for the Tamor and Seti basins, respectively. With 7% of original forest land removed, sediment yield for Tamor basin was estimated to be 65% higher, but increased to 124% for the SRES-B1 scenario. For the Seti basin, 4% deforestation yielded 33% more sediment for the SRES-A1B scenario. Our results indicated that combined effects of future, intensified monsoon rainfall with deforestation lead to dramatic potential for increased stream discharge and sediment yield as rainfall on steep slopes with thin exposed soils increases surface runoff and soil erosion in the Himalayas. This effect appears to

  15. Creating Dynamically Downscaled Seasonal Climate Forecast and Climate Change Projection Information for the North American Monsoon Region Suitable for Decision Making Purposes

    Science.gov (United States)

    Castro, C. L.; Dominguez, F.; Chang, H.

    2010-12-01

    Current seasonal climate forecasts and climate change projections of the North American monsoon are based on the use of course-scale information from a general circulation model. The global models, however, have substantial difficulty in resolving the regional scale forcing mechanisms of precipitation. This is especially true during the period of the North American Monsoon in the warm season. Precipitation is driven primarily due to the diurnal cycle of convection, and this process cannot be resolve in coarse-resolution global models that have a relatively poor representation of terrain. Though statistical downscaling may offer a relatively expedient method to generate information more appropriate for the regional scale, and is already being used in the resource decision making processes in the Southwest U.S., its main drawback is that it cannot account for a non-stationary climate. Here we demonstrate the use of a regional climate model, specifically the Weather Research and Forecast (WRF) model, for dynamical downscaling of the North American Monsoon. To drive the WRF simulations, we use retrospective reforecasts from the Climate Forecast System (CFS) model, the operational model used at the U.S. National Center for Environmental Prediction, and three select “well performing” IPCC AR 4 models for the A2 emission scenario. Though relatively computationally expensive, the use of WRF as a regional climate model in this way adds substantial value in the representation of the North American Monsoon. In both cases, the regional climate model captures a fairly realistic and reasonable monsoon, where none exists in the driving global model, and captures the dominant modes of precipitation anomalies associated with ENSO and the Pacific Decadal Oscillation (PDO). Long-term precipitation variability and trends in these simulations is considered via the standardized precipitation index (SPI), a commonly used metric to characterize long-term drought. Dynamically

  16. Representation of monsoon intraseasonal oscillations in regional climate model: sensitivity to convective physics

    KAUST Repository

    Umakanth, U.

    2015-11-07

    The aim of the study is to evaluate the performance of regional climate model (RegCM) version 4.4 over south Asian CORDEX domain to simulate seasonal mean and monsoon intraseasonal oscillations (MISOs) during Indian summer monsoon. Three combinations of Grell (G) and Emanuel (E) cumulus schemes namely, RegCM-EG, RegCM-EE and RegCM-GE have been used. The model is initialized at 1st January, 2000 for a 13-year continuous simulation at a spatial resolution of 50 km. The models reasonably simulate the seasonal mean low level wind pattern though they differ in simulating mean precipitation pattern. All models produce dry bias in precipitation over Indian land region except in RegCM-EG where relatively low value of dry bias is observed. On seasonal scale, the performance of RegCM-EG is more close to observation though it fails at intraseasonal time scales. In wave number-frequency spectrum, the observed peak in zonal wind (850 hPa) at 40–50 day scale is captured by all models with a slight change in amplitude, however, the 40–50 day peak in precipitation is completely absent in RegCM-EG. The space–time characteristics of MISOs are well captured by RegCM-EE over RegCM-GE, however it fails to show the eastward propagation of the convection across the Maritime Continent. Except RegCM-EE all other models completely underestimates the moisture advection from Equatorial Indian Ocean onto Indian land region during life-cycle of MISOs. The characteristics of MISOs are studied for strong (SM) and weak (WM) monsoon years and the differences in model performances are analyzed. The wavelet spectrum of rainfall over central India denotes that, the SM years are dominated by high frequency oscillations (period <20 days) whereas little higher periods (>30 days) along with dominated low periods (<20 days) observed during WM years. During SM, RegCM-EE is dominated with high frequency oscillations (period <20 days) whereas in WM, RegCM-EE is dominated with periods >20

  17. Late Holocene vegetation and climate change on the southeastern Tibetan Plateau: Implications for the Indian Summer Monsoon and links to the Indian Ocean Dipole

    Science.gov (United States)

    Li, Kai; Liu, Xingqi; Wang, Yongbo; Herzschuh, Ulrike; Ni, Jian; Liao, Mengna; Xiao, Xiayun

    2017-12-01

    The Indian Summer Monsoon (ISM) is one of the most important climate systems, whose variability and driving mechanisms are of broad interest for academic and societal communities. Here, we present a well-dated high-resolution pollen analysis from a 4.82-m long sediment core taken from Basomtso, in the southeastern Tibetan Plateau (TP), which depicts the regional climate changes of the past millennium. Our results show that subalpine coniferous forest was dominant around Basomtso from ca. 867 to ca. 750 cal. yr BP, indicating a warm and semi-humid climate. The timberline in the study area significantly decreased from ca. 750 to ca. 100 cal. yr BP, and a cold climate, corresponding to the Little Ice Age (LIA) prevailed. Since ca. 100 cal. yr BP, the vegetation type changed to forest-meadow with rising temperatures and moisture. Ordination analysis reveals that the migration of vegetation was dominated by regional temperatures and then by moisture. Further comparisons between the Basomtso pollen record and the regional temperature reconstructions underscore the relevance of the Basomtso record from the southeastern TP for regional and global climatologies. Our pollen based moisture reconstruction demonstrates the strong multicentennial-scale link to ISM variability, providing solid evidence for the increase of monsoonal strengths over the past four centuries. Spectral analysis indicates the potential influence of solar forcing. However, a closer relationship has been observed between multicentennial ISM variations and Indian Ocean sea surface temperature anomalies (SSTs), suggesting that the variations in monsoonal precipitation over the southeastern TP are probably driven by the Indian Ocean Dipole on the multicentennial scale.

  18. Daily modes of South Asian summer monsoon variability in the NCEP climate forecast system

    Energy Technology Data Exchange (ETDEWEB)

    Achuthavarier, Deepthi; Krishnamurthy, V. [George Mason University, Department of Atmospheric, Oceanic and Earth Sciences, Fairfax, VA (United States); Institute of Global Environment and Society, Center for Ocean-Land-Atmosphere Studies, Calverton, MD (United States)

    2011-05-15

    The leading modes of daily variability of the Indian summer monsoon in the climate forecast system (CFS), a coupled general circulation model, of the National Centers for Environmental Predictions (NCEP) are examined. The space-time structures of the daily modes are obtained by applying multi-channel singular spectrum analysis (MSSA) on the daily anomalies of rainfall. Relations of the daily modes to intraseasonal and interannual variability of the monsoon are investigated. The CFS has three intraseasonal oscillations with periods around 106, 57 and 30 days with a combined variance of 7%. The 106-day mode has spatial structure and propagation features similar to the northeastward propagating 45-day mode in the observations except for its longer period. The 57-day mode, despite being in the same time scale as of the observations has poor eastward propagation. The 30-day mode is northwestward propagating and is similar to its observational counterpart. The 106-day mode is specific to the model and should not be mistaken for a new scale of variability in observations. The dominant interannual signal is related to El Nino-Southern Oscillation (ENSO), and, unlike in the observations, has maximum variance in the eastern equatorial Indian Ocean. Although the Indian Ocean Dipole (IOD) mode was not obtained as a separate mode in the rainfall, the ENSO signal has good correlations with the dipole variability, which, therefore, indicates the dominance of ENSO in the model. The interannual variability is largely determined by the ENSO signal over the regions where it has maximum variance. The interannual variability of the intraseasonal oscillations is smaller in comparison. (orig.)

  19. Progress Towards Achieving the Challenge of Indian Summer Monsoon Climate Simulation in a Coupled Ocean-Atmosphere Model

    Science.gov (United States)

    Hazra, Anupam; Chaudhari, Hemantkumar S.; Saha, Subodh Kumar; Pokhrel, Samir; Goswami, B. N.

    2017-10-01

    Simulation of the spatial and temporal structure of the monsoon intraseasonal oscillations (MISOs), which have effects on the seasonal mean and annual cycle of Indian summer monsoon (ISM) rainfall, remains a grand challenge for the state-of-the-art global coupled models. Biases in simulation of the amplitude and northward propagation of MISOs and related dry rainfall bias over ISM region in climate models are limiting the current skill of monsoon prediction. Recent observations indicate that the convective microphysics of clouds may be critical in simulating the observed MISOs. The hypothesis is strongly supported by high fidelity in simulation of the amplitude and space-time spectra of MISO by a coupled climate model, when our physically based modified cloud microphysics scheme is implemented in conjunction with a modified new Simple Arakawa Schubert (nSAS) convective parameterization scheme. Improved simulation of MISOs appears to have been aided by much improved simulation of the observed high cloud fraction and convective to stratiform rain fractions and resulted into a much improved simulation of the ISM rainfall, monsoon onset, and the annual cycle.

  20. Assessment of two versions of regional climate model in simulating the Indian Summer Monsoon over South Asia CORDEX domain

    Science.gov (United States)

    Pattnayak, K. C.; Panda, S. K.; Saraswat, Vaishali; Dash, S. K.

    2018-04-01

    This study assess the performance of two versions of Regional Climate Model (RegCM) in simulating the Indian summer monsoon over South Asia for the period 1998 to 2003 with an aim of conducting future climate change simulations. Two sets of experiments were carried out with two different versions of RegCM (viz. RegCM4.2 and RegCM4.3) with the lateral boundary forcings provided from European Center for Medium Range Weather Forecast Reanalysis (ERA-interim) at 50 km horizontal resolution. The major updates in RegCM4.3 in comparison to the older version RegCM4.2 are the inclusion of measured solar irradiance in place of hardcoded solar constant and additional layers in the stratosphere. The analysis shows that the Indian summer monsoon rainfall, moisture flux and surface net downward shortwave flux are better represented in RegCM4.3 than that in the RegCM4.2 simulations. Excessive moisture flux in the RegCM4.2 simulation over the northern Arabian Sea and Peninsular India resulted in an overestimation of rainfall over the Western Ghats, Peninsular region as a result of which the all India rainfall has been overestimated. RegCM4.3 has performed well over India as a whole as well as its four rainfall homogenous zones in reproducing the mean monsoon rainfall and inter-annual variation of rainfall. Further, the monsoon onset, low-level Somali Jet and the upper level tropical easterly jet are better represented in the RegCM4.3 than RegCM4.2. Thus, RegCM4.3 has performed better in simulating the mean summer monsoon circulation over the South Asia. Hence, RegCM4.3 may be used to study the future climate change over the South Asia.

  1. South American climate during the Last Glacial Maximum: Delayed onset of the South American monsoon

    Science.gov (United States)

    Cook, K. H.; Vizy, E. K.

    2006-01-01

    The climate of the Last Glacial Maximum (LGM) over South America is simulated using a regional climate model with 60-km resolution, providing a simulation that is superior to those available from global models that do not resolve the topography and regional-scale features of the South American climate realistically. LGM conditions on SST, insolation, vegetation, and reduced atmospheric CO2 on the South American climate are imposed together and individually. Remote influences are not included. Annual rainfall is 25-35% lower in the LGM than in the present day simulation throughout the Amazon basin. A primary cause is a 2-3 month delay in the onset of the rainy season, so that the dry season is about twice as long as in the present day. The delayed onset occurs because the low-level inflow from the tropical Atlantic onto the South American continent is drier than in the present day simulation due to reduced evaporation from cooler surface waters, and this slows the springtime buildup of moist static energy that is needed to initiate convection. Once the monsoon begins in the Southern Hemisphere, LGM rainfall rates are similar to those in the present day. In the Northern Hemisphere, however, rainfall is lower throughout the (shortened) rainy season. Regional-scale structure includes slight precipitation increases in the Nordeste region of Brazil and along the eastern foothills of the Andes, and a region in the center of the Amazon basin that does not experience annual drying. In the Andes Mountains, the signal is complicated, with regions of significant rainfall increases adjacent to regions with reduced precipitation.

  2. Do differences in future sulfate emission pathways matter for near-term climate? A case study for the Asian monsoon

    Science.gov (United States)

    Bartlett, Rachel E.; Bollasina, Massimo A.; Booth, Ben B. B.; Dunstone, Nick J.; Marenco, Franco; Messori, Gabriele; Bernie, Dan J.

    2018-03-01

    Anthropogenic aerosols could dominate over greenhouse gases in driving near-term hydroclimate change, especially in regions with high present-day aerosol loading such as Asia. Uncertainties in near-future aerosol emissions represent a potentially large, yet unexplored, source of ambiguity in climate projections for the coming decades. We investigated the near-term sensitivity of the Asian summer monsoon to aerosols by means of transient modelling experiments using HadGEM2-ES under two existing climate change mitigation scenarios selected to have similar greenhouse gas forcing, but to span a wide range of plausible global sulfur dioxide emissions. Increased sulfate aerosols, predominantly from East Asian sources, lead to large regional dimming through aerosol-radiation and aerosol-cloud interactions. This results in surface cooling and anomalous anticyclonic flow over land, while abating the western Pacific subtropical high. The East Asian monsoon circulation weakens and precipitation stagnates over Indochina, resembling the observed southern-flood-northern-drought pattern over China. Large-scale circulation adjustments drive suppression of the South Asian monsoon and a westward extension of the Maritime Continent convective region. Remote impacts across the Northern Hemisphere are also generated, including a northwestward shift of West African monsoon rainfall induced by the westward displacement of the Indian Ocean Walker cell, and temperature anomalies in northern midlatitudes linked to propagation of Rossby waves from East Asia. These results indicate that aerosol emissions are a key source of uncertainty in near-term projection of regional and global climate; a careful examination of the uncertainties associated with aerosol pathways in future climate assessments must be highly prioritised.

  3. The Preboreal-like Asian monsoon climate in the early last interglacial period recorded from the Dark Cave, Southwest China

    Science.gov (United States)

    Jiang, Xiuyang; He, Yaoqi; Wang, Xiaoyan; Sun, Xiaoshuang; Hong, Hui; Liu, Juan; Yu, Tsai-Luen; Li, Zhizhong; Shen, Chuan-Chou

    2017-08-01

    Transitions of glacial-interglacial cycles are critical periods for Quaternary climate shifts. Here, we present new, decadal resolution Asian summer monsoon (ASM) record from three stalagmites obtained from the Dark Cave in southwestern China over 130-114 thousand years ago (ka, before CE 1950). Chronology was anchored by 28 230Th dates with typical uncertainties of ±0.3-1.0 kyr, allowing an assessment of timing and transition of climate changes during the onset and end of the last interglacial. An agreement between this new and previous stalagmite δ18O records supports that summer insolation predominates orbital-scale ASM evolution. A 2-3 kyr-long gradually increasing ASM period, analogous to the classical Preboreal episode in the early Holocene, follows the termination of a weak monsoon interval at 129.0 ± 0.8 ka. This finding suggests a strong influence of high-latitude ice-sheet dynamics on Asian monsoonal conditions during the early interglacial period. An abrupt end of the marine isotope stage 5e at 118.8 ± 0.6 ka was probably caused by the internal climate system threshold effects.

  4. Rainfall variability, climate change and regionalization in the African monsoon region

    International Nuclear Information System (INIS)

    Fontaine, Bernard; Roucou, Pascal; Vigaud, Nicolas; Camara, Moctar; Konare, Abdourahamane; Sanda, Seidou Ibrah; Diedhiou, Arona; Janicot, Serge

    2012-01-01

    This summary recalls some results at the end of the AMMA international experiment (2003-2010) in terms of variability of the African monsoon at the intra-seasonal to multi-decadal scales and of climate prospective. The results confirmed the weight of surface temperatures and marine tele-connections for inter-annual and decadal fluctuations and stressed the importance of atmospheric variability. They also described the dominant modes of intra-seasonal variability as their interactions with the surface. Several hypotheses involving memory effects related to soil water and vegetation, particularly in boreal spring and autumn have also been made. Prospective analysis from model output suggests rainfall surplus around 2050 over the Eastern-central Sahel and relative deficit to the West. Phase 2 of AMMA (2010-2020) will focus more on aspects that have a high social impact in direct collaboration with meteorological services predictability, prediction scores, operational indicators, evaluation of the part of anthropogenic forcing in the current and future variations. (authors)

  5. Synchronicity of the East Asian Summer Monsoon variability and Northern Hemisphere climate change since the last deglaciation

    OpenAIRE

    T. Shinozaki; M. Uchida; K. Minoura; M. Kondo; S. F. Rella; Y. Shibata

    2011-01-01

    Understanding of the mechanism of the East Asian Summer Monsoon (EASM) is required for the prediction of climate change in East Asia in a scenario of modern global warming. In this study, we present high-resolution climate records from peat sediments in Northeast Japan to reconstruct the EASM variability based on peat bulk cellulose δ13C since the last deglaciation. We used a 8.8 m long peat sediment core collected from the Tashiro Bog, Northeast Japan. Based ...

  6. The role of the Asian winter monsoon in the rapid propagation of abrupt climate changes during the last deglaciation

    Science.gov (United States)

    Chu, Guoqiang; Sun, Qing; Zhu, Qingzeng; Shan, Yabing; Shang, Wenyu; Ling, Yuan; Su, Youliang; Xie, Manman; Wang, Xishen; Liu, Jiaqi

    2017-12-01

    High-resolution temperature records spanning the last deglaciation from low latitudes are scarce; however, they are important for understanding the rapid propagation of abrupt climate events throughout the Northern Hemisphere and the tropics. Here, we present a branched GDGTs-based temperature reconstruction from the sediments of Maar Lake Huguangyan in tropical China. The record reveals that the mean temperature during the Oldest Dryas was 17.8 °C, which was followed by a two-step increase of 2-3 °C to the Bølling-Allerød, a decrease to 19.8 °C during the Younger Dryas, and a rapid warming at the onset of the Holocene. The Oldest Dryas was about 2 °C warmer than the Younger Dryas. The reconstructed temperature was weighted towards the wintertime since the lake is monomictic and the mixing process in winter supplies nutrients from the lake bottom to the entire water column, greatly promoting biological productivity. In addition, the winter-biased temperature changes observed in the study are more distinctive than the summer-biased temperature records from extra-tropical regions of East Asia. This implies that the temperature decreases during abrupt climatic events were mainly a winter phenomenon. Within the limits of the dating uncertainties, the broadly similar pattern of winter-weighted temperature change observed in both tropical Lake Huguangyan and in Greenland ice cores indicates the occurrence of tightly-coupled interactions between high latitude ice sheets and land areas in the tropics. We suggest that the winter monsoon (especially cold surges) could play an important role in the rapid transmission of the temperature signal from the Arctic to the tropics.

  7. East Asian winter monsoon forecasting schemes based on the NCEP's climate forecast system

    Science.gov (United States)

    Tian, Baoqiang; Fan, Ke; Yang, Hongqing

    2017-12-01

    The East Asian winter monsoon (EAWM) is the major climate system in the Northern Hemisphere during boreal winter. In this study, we developed two schemes to improve the forecasting skill of the interannual variability of the EAWM index (EAWMI) using the interannual increment prediction method, also known as the DY method. First, we found that version 2 of the NCEP's Climate Forecast System (CFSv2) showed higher skill in predicting the EAWMI in DY form than not. So, based on the advantage of the DY method, Scheme-I was obtained by adding the EAWMI DY predicted by CFSv2 to the observed EAWMI in the previous year. This scheme showed higher forecasting skill than CFSv2. Specifically, during 1983-2016, the temporal correlation coefficient between the Scheme-I-predicted and observed EAWMI was 0.47, exceeding the 99% significance level, with the root-mean-square error (RMSE) decreased by 12%. The autumn Arctic sea ice and North Pacific sea surface temperature (SST) are two important external forcing factors for the interannual variability of the EAWM. Therefore, a second (hybrid) prediction scheme, Scheme-II, was also developed. This scheme not only involved the EAWMI DY of CFSv2, but also the sea-ice concentration (SIC) observed the previous autumn in the Laptev and East Siberian seas and the temporal coefficients of the third mode of the North Pacific SST in DY form. We found that a negative SIC anomaly in the preceding autumn over the Laptev and the East Siberian seas could lead to a significant enhancement of the Aleutian low and East Asian westerly jet in the following winter. However, the intensity of the winter Siberian high was mainly affected by the third mode of the North Pacific autumn SST. Scheme-I and Scheme-II also showed higher predictive ability for the EAWMI in negative anomaly years compared to CFSv2. More importantly, the improvement in the prediction skill of the EAWMI by the new schemes, especially for Scheme-II, could enhance the forecasting skill of

  8. 8000-year monsoonal record from Himalaya revealing reinforcement of tropical and global climate systems since mid-Holocene.

    Science.gov (United States)

    Srivastava, Pradeep; Agnihotri, Rajesh; Sharma, Deepti; Meena, Narendra; Sundriyal, Y P; Saxena, Anju; Bhushan, Ravi; Sawlani, R; Banerji, Upasana S; Sharma, C; Bisht, P; Rana, N; Jayangondaperumal, R

    2017-11-06

    We provide the first continuous Indian Summer Monsoon (ISM) climate record for the higher Himalayas (Kedarnath, India) by analyzing a 14 C-dated peat sequence covering the last ~8000 years, with ~50 years temporal resolution. The ISM variability inferred using various proxies reveal striking similarity with the Greenland ice core (GISP2) temperature record and rapid denitrification changes recorded in the sediments off Peru. The Kedarnath record provides compelling evidence for a reorganization of the global climate system taking place at ~5.5 ka BP possibly after sea level stabilization and the advent of inter-annual climate variability governed by the modern ENSO phenomenon. The ISM record also captures warm-wet and cold-dry conditions during the Medieval Climate Anomaly and Little Ice Age, respectively.

  9. Effect of Floodplain Inundation on River Pollution in Taiwan's Strong Monsoonal Climate

    Science.gov (United States)

    Hester, E. T.; Lin, A. Y. C.

    2017-12-01

    River-floodplain interaction provides important benefits such as flood mitigation, provision of ecological habitat, and improved water quality. Human actions have historically reduced such interaction and associated benefits by diking, floodplain fill, and river regulation. In response, floodplain restoration has become popular in North America and Europe, but is less practiced in Asia. In Taiwan, unusually strong monsoons and steep terrain alter floodplain dynamics relative to elsewhere around the world, and provide a unique environment for floodplain management. We used numerical models of flow, transport, and reaction in river channels and floodplains to quantify the effect of river-floodplain interaction on water quality in Taiwan's strong monsoon and high topographic relief. We conducted sensitivity analyses of parameters such as river slope, monsoon severity, reservoir operation mode, degree of floodplain reconnection, contaminant reaction rate, and contaminant reaction type on floodplain connectivity and contaminant mitigation. We found significant differences in floodplain hydraulics and residence times in Taiwan's steep monsoonal environment relative to the shallower non-monsoonal environment typical of the eastern USA, with significant implications for water quality. For example, greater flashiness of floodplain inundation in Taiwan provides greater challenges for reconnecting sufficient floodplain volume to handle monsoonal runoff. Yet longer periods when floodplains are reliably dry means that such lands may have greater value for seasonal use such as parks or agriculture. The potential for floodplain restoration in Taiwan is thus significant, but qualitatively different than in the eastern USA.

  10. GIS development to monitor climate change and its geohydrological consequences on non-monsoon crop pattern in Himalaya

    Science.gov (United States)

    Rawat, Pradeep K.

    2014-09-01

    The main objective of the study was to assess climate change and its geohydrological impacts on non-monsoon crop pattern at watershed level through GIS development on climate informatics, land use informatics, hydro-informatics and agro-informatics. The Dabka watershed constitutes a part of the Kosi Basin in densely populated Lesser Himalaya, India in district Nainital has been selected for the case illustration. This reconnaissance study analyzed the climatic database for last three decades (1982-2012) and estimates that the average temperature and evaporation loss have been rising with the rate of 0.07 °C/yr and 4.03 mm/yr respectively whereas the average rainfall has been decreasing with the rate of 0.60 mm/yr. These rates of climate change increasing with mounting elevations. Consequently the existing microclimatic zones (sub-tropical, temperate and moist temperate) shifting towards higher altitudes and affecting the favorable conditions of the land use pattern and decreased the eco-friendly forest and vegetation cover. The land use degradation and high rate of deforestation (0.22 km2 or 1.5%/yr) leads to accelerate several hydrological problems during non-monsoon period (i.e. decreasing infiltration capacity of land surface, declining underground water level, drying up natural perennial springs and streams, decreasing irrigation water availability etc.). In order to that the non-monsoon crops yield has been decreasing with the rate of 0.60% each year as the results suggest that the average crop yield is just about 58 q/ha whereas twenty five to thirty year back it was recorded about 66 q/ha which is about 12% higher (8 q/ha) than existing yield. On the other hand the population increasing with the growth rate of 2% each year. Therefore, decreasing crop yield and increasing population raised food deficiency problem and the people adopting other occupations which ultimately affecting rural livelihood of the Himalaya.

  11. Aspect of ECMWF downscaled Regional Climate Modeling in simulating Indian summer monsoon rainfall and dependencies on lateral boundary conditions

    Science.gov (United States)

    Ghosh, Soumik; Bhatla, R.; Mall, R. K.; Srivastava, Prashant K.; Sahai, A. K.

    2018-03-01

    Climate model faces considerable difficulties in simulating the rainfall characteristics of southwest summer monsoon. In this study, the dynamical downscaling of European Centre for Medium-Range Weather Forecast's (ECMWF's) ERA-Interim (EIN15) has been utilized for the simulation of Indian summer monsoon (ISM) through the Regional Climate Model version 4.3 (RegCM-4.3) over the South Asia Co-Ordinated Regional Climate Downscaling EXperiment (CORDEX) domain. The complexities of model simulation over a particular terrain are generally influenced by factors such as complex topography, coastal boundary, and lack of unbiased initial and lateral boundary conditions. In order to overcome some of these limitations, the RegCM-4.3 is employed for simulating the rainfall characteristics over the complex topographical conditions. For reliable rainfall simulation, implementations of numerous lower boundary conditions are forced in the RegCM-4.3 with specific horizontal grid resolution of 50 km over South Asia CORDEX domain. The analysis is considered for 30 years of climatological simulation of rainfall, outgoing longwave radiation (OLR), mean sea level pressure (MSLP), and wind with different vertical levels over the specified region. The dependency of model simulation with the forcing of EIN15 initial and lateral boundary conditions is used to understand the impact of simulated rainfall characteristics during different phases of summer monsoon. The results obtained from this study are used to evaluate the activity of initial conditions of zonal wind circulation speed, which causes an increase in the uncertainty of regional model output over the region under investigation. Further, the results showed that the EIN15 zonal wind circulation lacks sufficient speed over the specified region in a particular time, which was carried forward by the RegCM output and leads to a disrupted regional simulation in the climate model.

  12. Climatic change in Mediterranean area

    International Nuclear Information System (INIS)

    Manos, A.

    1991-01-01

    United Nations Environmental Program (UNEP) studies on forecasted greenhouse climatic effects on the Mediterranean coastal and marine ecosystems and regional socio-economic framework have indicated the need for a concerted plan of protective and remedial action. The studies considered rises of 1.5 degrees in ambient temperature and 20 centimeters in sea level occurring before the year 2025. A regional, as opposed to a global area, study approach was adopted since the severity of climatic effects is expected to vary greatly from one part of the world to another. The specific areas investigated were the Po River Delta and Venezia Lagoon in Italy, the Nile Delta, Camargue, the Ebro Delta, the Tunisian National Park area, and the Thermaicos Gulf in Greece. The rise in average temperature is expected to negatively effect Mediterranean agricultural production and the coastal and marine ecosystems due to prolonged periods of drought and exceptional rainfall. It is suggested that a system of dikes be constructed to protect the coastal areas which are heavily dependent on tourism and agriculture

  13. Climatic differences and similarities between Indian and East Asian Monsoon regions of China over the last millennium: a perspective based mainly on stalagmite records.

    Directory of Open Access Journals (Sweden)

    Ming Tan

    2007-07-01

    Full Text Available Cave sediments, especially stalagmites, have been providing absolute dated climate records that can extend from the present to over 500,000 years ago. Based on the reconstructed temperature time series, a comprehensive overview of the climatic differences and similarities between the Indian and the East Asian Monsoon regions of China over the last millennium is presented. Evidence from accurately dated and high-resolution records including stalagmites, ice cores and tree rings show that there was a “Medieval Warm Period” (around 1000 to 1400 AD in north and east China where climate is dominated by the East Asian monsoon; whilst no such interval is evident in the records including stalagmites and ice cores from southwest China where climate is dominated by the Indian monsoon. However, both regions underwent a significant cooling during the Little Ice Age (around the mid 1500s to the 1800s. The result achieved here may allow a possibility of distinguishing the boundary between Indian monsoon and East Asian monsoon regions over the last millennium with increase of climate records, especially stalagmites that are mostly suitable for accurate U/Th dating and/or lamina counting.

  14. Relevance of Indian Summer Monsoon and its Tropical Indo-Pacific Climate Drivers for the Kharif Crop Production

    Science.gov (United States)

    Amat, Hemadri Bhusan; Karumuri, Ashok

    2017-12-01

    While the Indian agriculture has earlier been dependent on the Indian summer monsoon rainfall (ISMR), a multifold increase in irrigation and storage facilities raise a question whether the ISMR is still as relevant. We revisit this question using the latest observational climate datasets as well as the crop production data and find that the ISMR is still relevant for the Kharif crop production (KCP). In addition, in the recent changes in the tropical Indo-Pacific driver evolutions and frequency, particularly more frequent occurrence of the ENSO Modokis in place of the canonical ENSOs, we carry out a correlation analysis to estimate the impact of the various Indo-Pacific climate drivers on the rainfall of individual Indian states for the period 1998-2013, for which crop production data for the most productive Indian states, namely West Bengal, Odisha, United Andhra Pradesh (UAP), Haryana, Punjab, Karnataka, Kerala, Madhya Pradesh, Bihar and Uttar Pradesh are available. The results suggest that the KCP of the respective states are significantly correlated with the summer monsoon rainfall at the 95-99% confidence levels. Importantly, we find that the NINO 3.4 and ENSO Modoki indices have a statistically significant correlation with the KCP of most of the Indian states, particularly in states such as UAP and Karnataka, through induction of anomalous local convergence/divergence, well beyond the equatorial Indian Ocean. The KCP of districts in UAP also has a significant response to all the climate drivers, having implication for prediction of local crop yield.

  15. An abrupt centennial-scale drought event and mid-holocene climate change patterns in monsoon marginal zones of East Asia.

    Directory of Open Access Journals (Sweden)

    Yu Li

    Full Text Available The mid-latitudes of East Asia are characterized by the interaction between the Asian summer monsoon and the westerly winds. Understanding long-term climate change in the marginal regions of the Asian monsoon is critical for understanding the millennial-scale interactions between the Asian monsoon and the westerly winds. Abrupt climate events are always associated with changes in large-scale circulation patterns; therefore, investigations into abrupt climate changes provide clues for responses of circulation patterns to extreme climate events. In this paper, we examined the time scale and mid-Holocene climatic background of an abrupt dry mid-Holocene event in the Shiyang River drainage basin in the northwest margin of the Asian monsoon. Mid-Holocene lacustrine records were collected from the middle reaches and the terminal lake of the basin. Using radiocarbon and OSL ages, a centennial-scale drought event, which is characterized by a sand layer in lacustrine sediments both from the middle and lower reaches of the basin, was absolutely dated between 8.0-7.0 cal kyr BP. Grain size data suggest an abrupt decline in lake level and a dry environment in the middle reaches of the basin during the dry interval. Previous studies have shown mid-Holocene drought events in other places of monsoon marginal zones; however, their chronologies are not strong enough to study the mechanism. According to the absolutely dated records, we proposed a new hypothesis that the mid-Holocene dry interval can be related to the weakening Asian summer monsoon and the relatively arid environment in arid Central Asia. Furthermore, abrupt dry climatic events are directly linked to the basin-wide effective moisture change in semi-arid and arid regions. Effective moisture is affected by basin-wide precipitation, evapotranspiration, lake surface evaporation and other geographical settings. As a result, the time scales of the dry interval could vary according to locations due to

  16. Sedimentology and geomorphology analysis of coastal area along pantai penarik, terengganu before and during northeast monsoon season

    Science.gov (United States)

    Yusoff, Tengku Ahmad Imran Ku; Shaufi Sokiman, Mohamad

    2017-10-01

    This research is conducted to understand the sedimentology and morphological change before and during the northeast monsoon at the east coast of peninsular Malaysia. The increase in wind speed, wave energy and rainfall during the northeast monsoon are believed to causes the coastal erosion to increase during the season. Rapid development along the east coast area might disrupt the sediments distribution which can increase the coastal erosion rate every year. The understanding on the sediments distribution, erosion and deposition as well as the morphological change can help to figure out if the coastal erosion can affect the infrastructure in the future. The result of the study can show the necessity to perform mitigation or any required action toward the problem that might happen

  17. Possible teleconnections between East and South Asian summer monsoon precipitation in projected future climate change

    Science.gov (United States)

    Woo, Sumin; Singh, Gyan Prakash; Oh, Jai-Ho; Lee, Kyoung-Min

    2018-01-01

    The present paper examined the teleconnections between two huge Asian summer monsoon components (South and East Asia) during three time slices in future: near-(2010-2039), mid-(2040-2069) and far-(2070-2100) futures under the RCP4.5 and RCP8.5 scenarios. For this purpose, a high-resolution atmospheric general circulation model is used and integrated at 40 km horizontal resolution. To get more insight into the relationships between the two Asian monsoon components, we have studied the spatial displaying correlation coefficients (CCs) pattern of precipitation over the entire Asian monsoon region with that of South Asia and three regions of East Asia (North China, Korea-Japan and Southern China) separately during the same three time slices. The possible factors responsible for these teleconnections are explored by using mean sea level pressure (MSLP) and wind fields at 850 hPa. The CC pattern of precipitation over South Asia shows an in-phase relationship with North China and an out-of-phase relationship with Korea-Japan, while precipitation variations over Korea-Japan and Southern China exhibit an out-of-phase relationship with South Asia. The CCs analysis between the two Asian blocks during different time slices shows the strongest CCs during the near and far future with the RCP8.5 scenario. The CC pattern of precipitation over Korea-Japan and Southern China with the wind (at 850 hPa) and MSLP fields indicate that the major parts of the moisture over Korea-Japan gets transported from the west Pacific along the western limb of NPSH, while the moisture over Southern China comes from the Bay of Bengal and South China Seas for good monsoon activity.

  18. Climate change threatens European conservation areas

    DEFF Research Database (Denmark)

    Bastos Araujo, Miguel; Alagador, Diogo; Cabeza, Mar

    2011-01-01

    Europe has the world's most extensive network of conservation areas. Conservation areas are selected without taking into account the effects of climate change. How effectively would such areas conserve biodiversity under climate change? We assess the effectiveness of protected areas and the Natura...... 2000 network in conserving a large proportion of European plant and terrestrial vertebrate species under climate change. We found that by 2080, 58 ± 2.6% of the species would lose suitable climate in protected areas, whereas losses affected 63 ± 2.1% of the species of European concern occurring...

  19. Probabilistic Near and Far-Future Climate Scenarios of Precipitation and Surface Temperature for the North American Monsoon Region Under a Weighted CMIP5-GCM Ensemble Approach.

    Science.gov (United States)

    Montero-Martinez, M. J.; Colorado, G.; Diaz-Gutierrez, D. E.; Salinas-Prieto, J. A.

    2017-12-01

    It is well known the North American Monsoon (NAM) region is already a very dry region which is under a lot of stress due to the lack of water resources on multiple locations of the area. However, it is very interesting that even under those conditions, the Mexican part of the NAM region is certainly the most productive in Mexico from the agricultural point of view. Thus, it is very important to have realistic climate scenarios for climate variables such as temperature, precipitation, relative humidity, radiation, etc. This study tries to tackle that problem by generating probabilistic climate scenarios using a weighted CMIP5-GCM ensemble approach based on the Xu et al. (2010) technique which is on itself an improved method from the better known Reliability Ensemble Averaging algorithm of Giorgi and Mearns (2002). In addition, it is compared the 20-plus GCMs individual performances and the weighted ensemble versus observed data (CRU TS2.1) by using different metrics and Taylor diagrams. This study focuses on probabilistic results reaching a certain threshold given the fact that those types of products could be of potential use for agricultural applications.

  20. The Eocene climate of China, the early elevation of the Tibetan Plateau and the onset of the Asian Monsoon.

    Science.gov (United States)

    Wang, Qing; Spicer, Robert A; Yang, Jian; Wang, Yu-Fei; Li, Cheng-Sen

    2013-12-01

    Eocene palynological samples from 37 widely distributed sites across China were analysed using co-existence approach to determine trends in space and time for seven palaeoclimate variables: Mean annual temperature, mean annual precipitation, mean temperature of the warmest month, mean temperature of the coldest month, mean annual range of temperature, mean maximum monthly precipitation and mean minimum monthly precipitation. Present day distributions and observed climates within China of the nearest living relatives of the fossil forms were used to find the range of a given variable in which a maximum number of taxa can coexist. Isotherm and isohyet maps for the early, middle and late Eocene were constructed. These illustrate regional changing patterns in thermal and precipitational gradients that may be interpreted as the beginnings of the modern Asian Monsoon system, and suggest that the uplift of parts of the Tibetan Plateau appear to have taken place by the middle to late Eocene. © 2013 John Wiley & Sons Ltd.

  1. The West African monsoon: Contribution of the AMMA multidisciplinary programme to the study of a regional climate system.

    Science.gov (United States)

    Lebel, T.; Janicot, S.; Redelsperger, J. L.; Parker, D. J.; Thorncroft, C. D.

    2015-12-01

    The AMMA international project aims at improving our knowledge and understanding of the West African monsoon and its variability with an emphasis on daily-to-interannual timescales. AMMA is motivated by an interest in fundamental scientific issues and by the societal need for improved prediction of the WAM and its impacts on water resources, health and food security for West African nations. The West African monsoon (WAM) has a distinctive annual cycle in rainfall that remains a challenge to understand and predict. The location of peak rainfall, which resides in the Northern Hemisphere throughout the year, moves from the ocean to the land in boreal spring. Around the end of June there is a rapid shift in the location of peak rainfall between the coast and around 10°N where it remains until about the end of August. In September the peak rainfall returns equatorward at a relatively steady pace and is located over the ocean again by November. The fact that the peak rainfall migrates irregularly compared to the peak solar heating is due to the interactions that occur between the land, the atmosphere and the ocean. To gain a better understanding of this complex climate system, a large international research programme was launched in 2002, the biggest of its kind into environment and climate ever attempted in Africa. AMMA has involved a comprehensive field experiment bringing together ocean, land and atmospheric measurements, on timescales ranging from hourly and daily variability up to the changes in seasonal activity over a number of years. This presentation will focus on the description of the field programme and its accomplishments, and address some key questions that have been recently identified to form the core of AMMA-Phase 2.

  2. Deficiencies and possibilities for long-lead coupled climate prediction of the Western North Pacific-East Asian summer monsoon

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sun-Seon; Ha, Kyung-Ja [Pusan National University, Division of Earth Environmental System, Busan (Korea, Republic of); Lee, June-Yi; Wang, Bin [University of Hawaii, Department of Meteorology and International Pacific Research Center, Honolulu, HI (United States); Schemm, Jae Kyung E. [Climate Prediction Center/NCEP, Camp Springs, MD (United States)

    2011-03-15

    Long-lead prediction of waxing and waning of the Western North Pacific (WNP)-East Asian (EA) summer monsoon (WNP-EASM) precipitation is a major challenge in seasonal time-scale climate prediction. In this study, deficiencies and potential for predicting the WNP-EASM precipitation and circulation one or two seasons ahead were examined using retrospective forecast data for the 26-year period of 1981-2006 from two operational couple models which are the National Centers for Environmental Prediction (NCEP) Climate Forecast System (CFS) and the Bureau of Meteorology Research Center (BMRC) Predictive Ocean-Atmosphere Model for Australia (POAMA). While both coupled models have difficulty in predicting summer mean precipitation anomalies over the region of interest, even for a 0-month lead forecast, they are capable of predicting zonal wind anomalies at 850 hPa several months ahead and, consequently, satisfactorily predict summer monsoon circulation indices for the EA region (EASMI) and for the WNP region (WNPSMI). It should be noted that the two models' multi-model ensemble (MME) reaches 0.40 of the correlation skill for the EASMI with a January initial condition and 0.75 for the WNPSMI with a February initial condition. Further analysis indicates that prediction reliability of the EASMI is related not only to the preceding El Nino and Southern Oscillation (ENSO) but also to simultaneous local SST variability. On other hand, better prediction of the WNPSMI is accompanied by a more realistic simulation of lead-lag relationship between the index and ENSO. It should also be noted that current coupled models have difficulty in capturing the interannual variability component of the WNP-EASM system which is not correlated with typical ENSO variability. To improve the long-lead seasonal prediction of the WNP-EASM precipitation, a statistical postprocessing was developed based on the multiple linear regression method. The method utilizes the MME prediction of the EASMI and

  3. Sensitivity studies on the impacts of Tibetan Plateau snowpack pollution on the Asian hydrological cycle and monsoon climate

    Science.gov (United States)

    Qian, Y.; Flanner, M.; Leung, R.; Wang, W.

    2012-04-01

    The Tibetan Plateau (TP) has long been identified to be critical in regulating the Asian monsoon climate and hydrological cycle. In this modeling study a series of numerical experiments with a global climate model are designed to simulate radiative effect of black carbon (BC) and dust in snow, and to assess the relative impacts of anthropogenic CO2 and carbonaceous particles in the atmosphere and snow on the snowpack over the TP and subsequent impacts on the Asian monsoon climate and hydrological cycle. Simulations results show a large BC content in snow over the TP, especially the southern slope. Because of the high aerosol content in snow and large incident solar radiation in the low latitude and high elevation, the TP exhibits the largest surface radiative flux changes induced by aerosols (e.g. BC, Dust) in snow compared to any other snow-covered regions in the world. Simulation results show that the aerosol-induced snow albedo perturbations generate surface radiative flux changes of 5-25 W m-2 during spring, with a maximum in April or May. BC-in-snow increases the surface air temperature by around 1.0oC averaged over the TP and reduces spring snowpack over the TP more than pre-industrial to present CO2 increase and carbonaceous particles in the atmosphere. As a result, runoff increases during late winter and early spring but decreases during late spring and early summer (i.e. a trend toward earlier melt dates). The snowmelt efficacy, defined as the snowpack reduction per unit degree of warming induced by the forcing agent, is 1-4 times larger for BC-in-snow than CO2 increase during April-July, indicating that BC-in-snow more efficiently accelerates snowmelt because the increased net solar radiation induced by reduced albedo melts the snow more efficiently than snow melt due to warming in the air. The TP also influences the South (SAM) and East (EAM) Asian monsoon through its dynamical and thermal forcing. Simulation results show that during boreal spring

  4. Sensitivity studies on the impacts of Tibetan Plateau snowpack pollution on the Asian hydrological cycle and monsoon climate

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Yun; Flanner, M G; Leung, Lai-Yung R; Wang, Weiguo

    2011-03-02

    The Tibetan Plateau (TP), the highest and largest plateau in the world, has long been identified to be critical in regulating the Asian monsoon climate and hydrological cycle. The snowpack and glaciers over the TP provide fresh water to billions of people in Asian countries, but the TP glaciers have been retreating extensively at a speed faster than any other part of the world. In this study a series of experiments with a global climate model are designed to simulate black carbon (BC) and dust in snow and their radiative forcing and to assess the relative impacts of anthropogenic CO2 and carbonaceous particles in the atmosphere and snow, respectively, on the snowpack over the TP, as well as their subsequent impacts on the Asian monsoon climate and hydrological cycle. Results show a large BC content in snow over the TP, especially the southern slope, with concentration larger than 100 µk/kg. Because of the high aerosol content in snow and large incident solar radiation in the low latitude and high elevation, the TP exhibits the largest surface radiative forcing induced by aerosols (e.g. BC, Dust) in snow compared to other snow-covered regions in the world. The aerosol-induced snow albedo perturbations generate surface radiative forcing of 5-25 W m-2 during spring, with a maximum in April or May. BC-in-snow increases the surface air temperature by around 1.0°C averaged over the TP and reduces snowpack over the TP more than that induced by pre-industrial to present CO2 increase and carbonaceous particles in the atmosphere during spring. As a result, runoff increases during late winter and early spring but decreases during late spring and early summer (i.e. a trend toward earlier melt dates). The snowmelt efficacy, defined as the snowpack reduction per unit degree of warming induced by the forcing agent, is 1-4 times larger for BC-in-snow than CO2 increase during April-July, indicating that BC-in-snow more efficiently

  5. A climate model study of an intense Asian Monsoon in a La Niña-like climate of MIS-13

    Science.gov (United States)

    Karami, M. P.; Berger, A.; Herold, N.; Yin, Q. Z.

    2012-04-01

    Studying the paleo-monsoon during past interglacials is a valuable approach to improve our understanding of the monsoon system in present-day and future climates. We focus on Marine Isotopic stage 13 (MIS-13; ~0.5 Ma) which was a relatively cool interglacial, but with a paradoxically intense monsoonal precipitation over eastern and southern Asia. Our main goal is to understand the physics-based mechanism driving the intense monsoon, specifically the East Asian Summer Monsoon (EASM), during MIS-13. We applied both an intermediate complexity model (LOVECLIM) as well as fully coupled general circulation models (HadCM3 and CCSM3) to simulate pre-industrial and MIS-13 climates. The boundary conditions for MIS-13 were chosen for 506 ka with Northern-Hemisphere (NH) summer at perihelion and a CO2 concentration of 240 ppm. For pre-industrial, NH-winter occurring at perihelion and a CO2 concentration of 280 ppm were prescribed. Preliminary analysis of the model results shows different atmospheric and oceanic features in MIS-13 compared to the pre-industrial which could affect the EASM. The Northern Pacific Subtropical High (NPSH), which is an important factor in controlling the EASM, strengthened and extended to the northwest in MIS-13 partially due to cooling of the central Pacific Ocean. This in turn brought more moisture from the Central Pacific to the EASM-region and caused a northwestward shift and bending of the low-level jet along East Asia. The change in the low-level jet subsequently increased the meridional wind velocity at 850 mbar in the EASM-region providing more moisture from the tropical Pacific and Indian Oceans. In addition, higher sea-surface temperature in the Indian Ocean during MIS-13 further increased the source of moisture for the EASM. The Asian low, which is another component of the EASM-system, also shifted eastward moving the rain band northward. Moreover, it was found that MIS-13 had a dominant La Niña condition in the tropical Pacific. La Ni

  6. Exploring recent and projected climate change in a steep monsoonal catchment in the middle Himalaya through innovative synthesis of local observations, gridded datasets and community engagement

    Science.gov (United States)

    Forsythe, Nathan; Pritchard, Davis; Tiwari, Prakash; Fowler, Hayley; Kumaun, Bhagwati

    2016-04-01

    Under the auspices of an "Innovation Partnerships" programme research exchange grant jointly funded by the India Department of Science and Technology and the British Council, Kumaun University and Newcastle University have been collaboratively exploring the recorded historical and projected future climate change implications for a case study catchment, the Ramgad river, in the Kumaon Lesser Himalaya (Uttarakhand state, India). This work weaves together diverse research strands with the aim of producing a coherent thorough characterisation of the impacts of recent/on-going and likely climate evolution on local communities. Participatory research activities in multiple villages in the case study catchment have yielded a consistent narrative of changes posed by the increasingly erratic monsoonal rainfall as well as upward displacement and replacement crops in their historical elevation ranges due to temperature change. Multi-decadal climate records from both local observations and global meteorological records reveal a more complex picture with strong seasonal asymmetry of changes in both temperature and precipitation: a) trend analysis shows mild weakening of the early phase (May, July) but strengthen in the later stages (August, September); b) temperature trends show much stronger warming in late winter and early spring (February to April) than the rest of the year with additional asymmetry in both sign and magnitude of change between individual components (Tmax, Tmin) of the diurnal temperature cycle. On-going research seeks to associate this asymmetry with causal mechanisms (cloud radiative effect, atmospheric circulation). Analysis of historical records will provide the basis for validation and assessment of individual regional climate model projections from the CORDEX South Asia domain ensemble. For the terraced agricultural communities of the Kumaon Himalaya, the most directly consequential effects of climate variability and change are impacts on crop yields

  7. Decadal shifts of East Asian summer monsoon in a climate model free of explicit GHGs and aerosols

    Science.gov (United States)

    Lin, Renping; Zhu, Jiang; Zheng, Fei

    2016-12-01

    The East Asian summer monsoon (EASM) experienced decadal transitions over the past few decades, and the associated "wetter-South-drier-North" shifts in rainfall patterns in China significantly affected the social and economic development in China. Two viewpoints stand out to explain these decadal shifts, regarding the shifts either a result of internal variability of climate system or that of external forcings (e.g. greenhouse gases (GHGs) and anthropogenic aerosols). However, most climate models, for example, the Atmospheric Model Intercomparison Project (AMIP)-type simulations and the Coupled Model Intercomparison Project (CMIP)-type simulations, fail to simulate the variation patterns, leaving the mechanisms responsible for these shifts still open to dispute. In this study, we conducted a successful simulation of these decadal transitions in a coupled model where we applied ocean data assimilation in the model free of explicit aerosols and GHGs forcing. The associated decadal shifts of the three-dimensional spatial structure in the 1990s, including the eastward retreat, the northward shift of the western Pacific subtropical high (WPSH), and the south-cool-north-warm pattern of the upper-level tropospheric temperature, were all well captured. Our simulation supports the argument that the variations of the oceanic fields are the dominant factor responsible for the EASM decadal transitions.

  8. Last Glacial Maximum to Holocene climate evolution controlled by sea-level change, Leeuwin Current, and Australian Monsoon in the Northwestern Australia

    Science.gov (United States)

    Ishiwa, T.; Yokoyama, Y.; McHugh, C.; Reuning, L.; Gallagher, S. J.

    2017-12-01

    The transition from cold to warm conditions during the last deglaciation influenced climate variability in the Indian Ocean and Pacific as a result of submerge of continental shelf and variations in the Indonesian Throughflow and Australian Monsoon. The shallow continental shelf (Program Expedition 356 Indonesian Throughflow drilled in the northwestern Australian shallow continental shelf and recovered an interval from the Last Glacial Maximum to Holocene in Site U1461. Radiocarbon dating on macrofossils, foraminifera, and bulk organic matter provided a precise age-depth model, leading to high-resolved paleoclimate reconstruction. X-ray elemental analysis results are interpreted as an indicator of sedimentary environmental changes. The upper 20-m part of Site U1461 apparently records the climate transition from the LGM to Holocene in the northwestern Australia, which could be associated with sea-level change, Leeuwin Current activity, and the Australian Monsoon.

  9. Real-Time Monitoring of Mountain Conifer Growth Response to Seasonal Climate and the Summer Monsoon in the Great Basin of North America

    Science.gov (United States)

    Strachan, S.; Biondi, F.

    2013-12-01

    Tree rings in the American intermountain west are often used for palaeoclimatic purposes, including reconstructions of precipitation, temperature, and drought. Specific seasonal phenomena such as the North American Monsoon (NAM) are also being identified in tree-ring studies as being related to certain growth features in the rings (such as early-onset 'false' latewood). These relationships have historically been developed using statistical relationships between tree-ring chronologies and regional weather observations. In zones near the periphery of the NAM, summertime precipitation may be more sporadic, yet localized vegetation assemblages in the northern Mojave desert and Great Basin regions indicate that these events are still important for some ecosystems which have established in areas where NAM activity is present. Major shifts in NAM behavior in the past may have been recorded by tree rings, and identifying the specific mechanisms/circumstances by which this occurs is critical for efforts seeking to model ecosystem response to climate changes. By establishing in-situ monitoring of climate/weather, soils, and tree-growth variables in Pinus ponderosa scopulorum and Pinus monophylla zones at study sites in eastern/southern Nevada, we are able to address these issues at very fine spatial and temporal scales. Data from two seasons of monitoring precipitation, solar radiation, air temperature, soil temperature, soil water content, tree sap flow, tree radial distance increment, and hourly imagery are presented. Point dendrometers along with sap flow sensors monitor growth in these ponderosa pine around the clock to help researchers understand tree-ring/climate relationships.

  10. Synchronicity of the East Asian Summer Monsoon variability and Northern Hemisphere climate change since the last deglaciation

    Science.gov (United States)

    Shinozaki, T.; Uchida, M.; Minoura, K.; Kondo, M.; Rella, S. F.; Shibata, Y.

    2011-06-01

    Understanding of the mechanism of the East Asian Summer Monsoon (EASM) is required for the prediction of climate change in East Asia in a scenario of modern global warming. In this study, we present high-resolution climate records from peat sediments in Northeast Japan to reconstruct the EASM variability based on peat bulk cellulose δ13C since the last deglaciation. We used a 8.8 m long peat sediment core collected from the Tashiro Bog, Northeast Japan. Based on 42 14C measurements, the core bottom reaches ~15.5 ka. δ13C, accumulation rate and accumulation flux time-series correlate well to Greenland ice core δ18O variability, suggesting that the climate record in Northeast Japan is linked to global climate changes. The δ13C record at Tashiro Bog and other paleo-EASM records at Northeast and Southern China consistently demonstrate that hydrological environments were spatially different in mid-high and mid-low latitude regions over the last 15.5 kyr. During global cooling (warming) periods, mid-high and mid-low latitude regions were characterized by wet (dry) and dry (wet) environments, respectively. We suggest that these climatic patterns are related to the migration of the EASM-related rain belt during global climate changes, as a consequence of variations in intensity and location of both the Intertropical Convergence Zone (ITCZ) and the Western Pacific Subtropical High (STH). The location of the rain belt largely influences the East Asian hydrological environment. Our δ13C time-series are characterized by a 1230 yr throughout the Holocene and a 680 yr periodicity during the early Holocene. The 1230 yr periodicity is in agreement with North Atlantic ice-rafted debris (IRD) events, suggesting a teleconnection between the Northeast Japan and the North Atlantic during the Holocene. In addition, it is the first evidence that the Bond events were recorded in terrestrial sediment in Japan. On the other hand, the 680 yr periodicity between 10.0 and 8.0 kyr is

  11. Transport of short-lived climate forcers/pollutants (SLCF/P) to the Himalayas during the South Asian summer monsoon onset

    International Nuclear Information System (INIS)

    Cristofanelli, P; Putero, D; Landi, T C; Marinoni, A; Duchi, R; Calzolari, F; Bonasoni, P; Adhikary, B; Stocchi, P; Verza, G; Vuillermoz, E; Laj, P; Kang, S; Ming, J

    2014-01-01

    Over the course of six years (2006–2011), equivalent black carbon (eqBC), coarse aerosol mass (PM 1–10 ), and surface ozone (O 3 ), observed during the monsoon onset period at the Nepal Climate Observatory–Pyramid WMO/GAW Global Station (NCO-P, 5079 m a.s.l.), were analyzed to investigate events characterized by a significant increase in these short-lived climate forcers/pollutants (SLCF/P). These events occurred during periods characterized by low (or nearly absent) rain precipitation in the central Himalayas, and they appeared to be related to weakening stages (or ‘breaking’) of the South Asian summer monsoon system. As revealed by the combined analysis of atmospheric circulation, air-mass three-dimensional back trajectories, and satellite measurements of atmospheric aerosol loading, surface open fire, and tropospheric NO x , the large amount of SLCF/P reaching the NCO-P appeared to be related to natural (mineral dust) and anthropogenic emissions occurring within the PBL of central Pakistan (i.e., Thar Desert), the Northwestern Indo-Gangetic plain, and the Himalayan foothills. The systematic occurrence of these events appeared to represent the most important source of SLCF/P inputs into the central Himalayas during the summer monsoon onset period, with possible important implications for the regional climate and for hydrological cycles. (letter)

  12. Weakening of the North American monsoon with global warming

    Science.gov (United States)

    Pascale, Salvatore; Boos, William R.; Bordoni, Simona; Delworth, Thomas L.; Kapnick, Sarah B.; Murakami, Hiroyuki; Vecchi, Gabriel A.; Zhang, Wei

    2017-11-01

    Future changes in the North American monsoon, a circulation system that brings abundant summer rains to vast areas of the North American Southwest, could have significant consequences for regional water resources. How this monsoon will change with increasing greenhouse gases, however, remains unclear, not least because coarse horizontal resolution and systematic sea-surface temperature biases limit the reliability of its numerical model simulations. Here we investigate the monsoon response to increased atmospheric carbon dioxide (CO2) concentrations using a 50-km-resolution global climate model which features a realistic representation of the monsoon climatology and its synoptic-scale variability. It is found that the monsoon response to CO2 doubling is sensitive to sea-surface temperature biases. When minimizing these biases, the model projects a robust reduction in monsoonal precipitation over the southwestern United States, contrasting with previous multi-model assessments. Most of this precipitation decline can be attributed to increased atmospheric stability, and hence weakened convection, caused by uniform sea-surface warming. These results suggest improved adaptation measures, particularly water resource planning, will be required to cope with projected reductions in monsoon rainfall in the American Southwest.

  13. Validation of the HIRHAM-Simulated Indian Summer Monsoon Circulation

    Directory of Open Access Journals (Sweden)

    Stefan Polanski

    2010-01-01

    Full Text Available The regional climate model HIRHAM has been applied over the Asian continent to simulate the Indian monsoon circulation under present-day conditions. The model is driven at the lateral and lower boundaries by European reanalysis (ERA40 data for the period from 1958 to 2001. Simulations with a horizontal resolution of 50 km are carried out to analyze the regional monsoon patterns. The focus in this paper is on the validation of the long-term summer monsoon climatology and its variability concerning circulation, temperature, and precipitation. Additionally, the monsoonal behavior in simulations for wet and dry years has been investigated and compared against several observational data sets. The results successfully reproduce the observations due to a realistic reproduction of topographic features. The simulated precipitation shows a better agreement with a high-resolution gridded precipitation data set over the central land areas of India and in the higher elevated Tibetan and Himalayan regions than ERA40.

  14. Application of regional climate models to the Indian winter monsoon over the western Himalayas.

    Science.gov (United States)

    Dimri, A P; Yasunari, T; Wiltshire, A; Kumar, P; Mathison, C; Ridley, J; Jacob, D

    2013-12-01

    The Himalayan region is characterized by pronounced topographic heterogeneity and land use variability from west to east, with a large variation in regional climate patterns. Over the western part of the region, almost one-third of the annual precipitation is received in winter during cyclonic storms embedded in westerlies, known locally as the western disturbance. In the present paper, the regional winter climate over the western Himalayas is analyzed from simulations produced by two regional climate models (RCMs) forced with large-scale fields from ERA-Interim. The analysis was conducted by the composition of contrasting (wet and dry) winter precipitation years. The findings showed that RCMs could simulate the regional climate of the western Himalayas and represent the atmospheric circulation during extreme precipitation years in accordance with observations. The results suggest the important role of topography in moisture fluxes, transport and vertical flows. Dynamical downscaling with RCMs represented regional climates at the mountain or even event scale. However, uncertainties of precipitation scale and liquid-solid precipitation ratios within RCMs are still large for the purposes of hydrological and glaciological studies. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. On unravelling mechanism of interplay between cloud and large scale circulation: a grey area in climate science

    Science.gov (United States)

    De, S.; Agarwal, N. K.; Hazra, Anupam; Chaudhari, Hemantkumar S.; Sahai, A. K.

    2018-04-01

    The interaction between cloud and large scale circulation is much less explored area in climate science. Unfolding the mechanism of coupling between these two parameters is imperative for improved simulation of Indian summer monsoon (ISM) and to reduce imprecision in climate sensitivity of global climate model. This work has made an effort to explore this mechanism with CFSv2 climate model experiments whose cloud has been modified by changing the critical relative humidity (CRH) profile of model during ISM. Study reveals that the variable CRH in CFSv2 has improved the nonlinear interactions between high and low frequency oscillations in wind field (revealed as internal dynamics of monsoon) and modulates realistically the spatial distribution of interactions over Indian landmass during the contrasting monsoon season compared to the existing CRH profile of CFSv2. The lower tropospheric wind error energy in the variable CRH simulation of CFSv2 appears to be minimum due to the reduced nonlinear convergence of error to the planetary scale range from long and synoptic scales (another facet of internal dynamics) compared to as observed from other CRH experiments in normal and deficient monsoons. Hence, the interplay between cloud and large scale circulation through CRH may be manifested as a change in internal dynamics of ISM revealed from scale interactive quasi-linear and nonlinear kinetic energy exchanges in frequency as well as in wavenumber domain during the monsoon period that eventually modify the internal variance of CFSv2 model. Conversely, the reduced wind bias and proper modulation of spatial distribution of scale interaction between the synoptic and low frequency oscillations improve the eastward and northward extent of water vapour flux over Indian landmass that in turn give feedback to the realistic simulation of cloud condensates attributing improved ISM rainfall in CFSv2.

  16. Analyzing the water budget and hydrological characteristics and responses to land use in a monsoonal climate river basin in South China

    Science.gov (United States)

    Wu, Yiping; Chen, Ji

    2013-01-01

    Hydrological models have been increasingly used by hydrologists and water resource managers to understand natural processes and human activities that affect watersheds. In this study, we use the physically based model, Soil and Water Assessment Tool (SWAT), to investigate the hydrological processes in the East River Basin in South China, a coastal area dominated by monsoonal climate. The SWAT model was calibrated using 8-year (1973–1980) record of the daily streamflow at the basin outlet (Boluo station), and then validated using data collected during the subsequent 8 years (1981–1988). Statistical evaluation shows that SWAT can consistently simulate the streamflow of the East River with monthly Nash–Sutcliffe efficiencies of 0.93 for calibration and 0.90 for validation at the Boluo station. We analyzed the model simulations with calibrated parameters, presented the spatiotemporal distribution of the key hydrological components, and quantified their responses to different land uses. Watershed managers can use the results of this study to understand hydrological features and evaluate water resources of the East River in terms of sustainable development and effective management.

  17. Measuring the monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaswamy, V.; Nair, R.R.

    that are constant enough to be used for navigation. But the monsoon also acts as a sign of the climatic times. Although its timing is remarkably regular, the intensity of its effects varies considerably from year to year. On top of natural variations in the strength...

  18. Fire history and climate characteristics during the last millennium of the Great Hinggan Mountains at the monsoon margin in northeastern China

    Science.gov (United States)

    Gao, Chuanyu; He, Jiabao; Zhang, Yan; Cong, Jinxin; Han, Dongxue; Wang, Guoping

    2018-03-01

    The northeastern region of China, at the limit of the summer monsoon, is characterized by the presence of mountains that influenced by the Asian summer monsoon on one side and the westerlies on the other; however, few studies have compared the environmental characteristics on the two sides of these mountains. In this study, two peatland cores from the western and eastern sides of the Great Hinggan Mountains were investigated to better understand the climatic and environmental conditions and the measurements of black carbon (BC) and δ13C-BC were used to reconstruct the fire history and environmental characteristics during the last millennium. Our results showed that the variations in the δ13C-BC values are more sensitive to climate changes than the BC fluxes, and the climate forcing mechanisms differed between the two sides of the mountains. Lower δ13C-BC values around 500 cal yr BP on the western side of the mountains indicated climate conditions were wetter than that on the eastern side, and were influenced by low sea surface temperatures in the North Atlantic Ocean. The region east of the mountains was mainly influenced by the strong Asian summer monsoon, and the decreasing of δ13C-BC values indicated climate conditions became wetter from 250 cal yr BP to the present and were wetter than that on the western side after 150 cal yr BP. Moreover, when one of these two forcing factors weakened and the other strengthened (e.g. from 400 to 150 cal yr BP), climate conditions in these two sides were similar.

  19. On the relationship between Indian summer monsoon withdrawal and Indo-Pacific SST anomalies before and after 1976/1977 climate shift

    Energy Technology Data Exchange (ETDEWEB)

    Sabeerali, C.T.; Rao, Suryachandra A. [Indian Institute of Tropical Meteorology, Pune (India); Ajayamohan, R.S. [University of Victoria, Canadian Centre for Climate Modelling and Analysis, Victoria, BC (Canada); Murtugudde, Raghu [University of Maryland, Earth System Science Interdisciplinary Center, College Park, MD (United States)

    2012-08-15

    A clear shift in the withdrawal dates of the Indian Summer Monsoon is observed in the long term time series of rainfall data. Prior (posterior) to the 1976/1977 climate shift most of the withdrawal dates are associated with a late (an early) withdrawal. As a result, the length of the rainy season (LRS) over the Indian land mass has also undergone similar changes (i.e., longer (shorter) LRS prior (posterior) to the climate shift). In this study, probable reasons for this significant shift in withdrawal dates and the LRS are investigated using reanalysis/observed datasets and also with the help of an atmospheric general circulation model. Reanalysis/observational datasets indicate that prior to the climate shift the sea surface temperature (SST) anomalies in the eastern equatorial Pacific Ocean and the Arabian Sea exerted a strong influence on both the withdrawal and the LRS. After the climate shift, the influence of the eastern equatorial Pacific Ocean SST has decreased and surprisingly, the influence of the Arabian Sea SST is almost non-existent. On the other hand, the influence of the southeastern equatorial Indian Ocean has increased significantly. It is observed that the upper tropospheric temperature gradient over the dominant monsoon region has decreased and the relative influence of the Indian Ocean SST variability on the withdrawal of the Indian Summer Monsoon has increased in the post climate shift period. Sensitivity experiments with the contrasting SST patterns on withdrawal dates and the LRS in the pre- and post- climate shift scenarios, confirm the observational evidences presented above. (orig.)

  20. Summer monsoon circulation and precipitation over the tropical Indian Ocean during ENSO in the NCEP climate forecast system

    Science.gov (United States)

    Chowdary, J. S.; Chaudhari, H. S.; Gnanaseelan, C.; Parekh, Anant; Suryachandra Rao, A.; Sreenivas, P.; Pokhrel, S.; Singh, P.

    2014-04-01

    This study investigates the El Niño Southern Oscillation (ENSO) teleconnections to tropical Indian Ocean (TIO) and their relationship with the Indian summer monsoon in the coupled general circulation model climate forecast system (CFS). The model shows good skill in simulating the impact of El Niño over the Indian Oceanic rim during its decay phase (the summer following peak phase of El Niño). Summer surface circulation patterns during the developing phase of El Niño are more influenced by local Sea Surface Temperature (SST) anomalies in the model unlike in observations. Eastern TIO cooling similar to that of Indian Ocean Dipole (IOD) is a dominant model feature in summer. This anomalous SST pattern therefore is attributed to the tendency of the model to simulate more frequent IOD events. On the other hand, in the model baroclinic response to the diabatic heating anomalies induced by the El Niño related warm SSTs is weak, resulting in reduced zonal extension of the Rossby wave response. This is mostly due to weak eastern Pacific summer time SST anomalies in the model during the developing phase of El Niño as compared to observations. Both eastern TIO cooling and weak SST warming in El Niño region combined together undermine the ENSO teleconnections to the TIO and south Asia regions. The model is able to capture the spatial patterns of SST, circulation and precipitation well during the decay phase of El Niño over the Indo-western Pacific including the typical spring asymmetric mode and summer basin-wide warming in TIO. The model simulated El Niño decay one or two seasons later, resulting long persistent warm SST and circulation anomalies mainly over the southwest TIO. In response to the late decay of El Niño, Ekman pumping shows two maxima over the southern TIO. In conjunction with this unrealistic Ekman pumping, westward propagating Rossby waves display two peaks, which play key role in the long-persistence of the TIO warming in the model (for more than a

  1. Helsinki Metropolitan Area Climate Change Adaptation Strategy

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-07-01

    The Helsinki Metropolitan Area Climate Change Adaptation Strategy has been prepared in close cooperation with the four cities of the metropolitan area (Helsinki, Espoo, Vantaa and Kauniainen), the Helsinki Region Environmental Services Authority HSY and other municipal, regional and state level organisations. In the strategy, strategic starting points and policies with which the metropolitan area prepares for the consequences of climate change, are compiled. The Helsinki Metropolitan Area adaptation strategy concentrates on the adaptation of the built and urban environment to the changing climate. The vision of the strategy is climate proof city - the future is built now. The strategy aims to (1) assess the impacts of climate change in the area, (2) prepare for the impacts of climate change and to extreme weather events and (3) to reduce the vulnerabilities of the area to climate variability and change. The target is to secure the well-being of the citizens and the functioning of the cities also in the changing climate conditions. The preparation of the adaptation strategy started in 2009 by producing the background studies. They include the regional climate and sea level scenarios, modelling of river floods in climate change conditions and a survey of climate change impacts in the region. Also, existing programmes, legislation, research and studies concerning adaptation were collected. The background studies are published in a report titled 'The Helsinki metropolitan area climate is changing - Adaptation strategy background studies' (in Finnish) (HSY 2010). HSY coordinated the strategy preparation. The work was carried out is close cooperation with the experts of the metropolitan area cities, regional emergency services, Ministry of the Environment, Helsinki Region Transport Authority and other regional organisations. The strategy work has had a steering group that consists of representatives of the cities and other central cooperation partners. The

  2. Recent change of the global monsoon precipitation (1979-2008)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bin [University of Hawaii at Manoa, Department of Meteorology, Honolulu, HI (United States); University of Hawaii at Manoa, International Pacific Research Center, Honolulu, HI (United States); Liu, Jian [Chinese Academy of Sciences, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Nanjing (China); Kim, Hyung-Jin [Japan Agency for Marine-Earth Science and Technology, Research Institute for Global Change, Yokohama, Kanagawa (Japan); Webster, Peter J. [Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, GA (United States); Yim, So-Young [University of Hawaii at Manoa, International Pacific Research Center, Honolulu, HI (United States)

    2012-09-15

    The global monsoon (GM) is a defining feature of the annual variation of Earth's climate system. Quantifying and understanding the present-day monsoon precipitation change are crucial for prediction of its future and reflection of its past. Here we show that regional monsoons are coordinated not only by external solar forcing but also by internal feedback processes such as El Nino-Southern Oscillation (ENSO). From one monsoon year (May to the next April) to the next, most continental monsoon regions, separated by vast areas of arid trade winds and deserts, vary in a cohesive manner driven by ENSO. The ENSO has tighter regulation on the northern hemisphere summer monsoon (NHSM) than on the southern hemisphere summer monsoon (SHSM). More notably, the GM precipitation (GMP) has intensified over the past three decades mainly due to the significant upward trend in NHSM. The intensification of the GMP originates primarily from an enhanced east-west thermal contrast in the Pacific Ocean, which is coupled with a rising pressure in the subtropical eastern Pacific and decreasing pressure over the Indo-Pacific warm pool. While this mechanism tends to amplify both the NHSM and SHSM, the stronger (weaker) warming trend in the NH (SH) creates a hemispheric thermal contrast, which favors intensification of the NHSM but weakens the SHSM. The enhanced Pacific zonal thermal contrast is largely a result of natural variability, whilst the enhanced hemispherical thermal contrast is likely due to anthropogenic forcing. We found that the enhanced global summer monsoon not only amplifies the annual cycle of tropical climate but also promotes directly a ''wet-gets-wetter'' trend pattern and indirectly a ''dry-gets-drier'' trend pattern through coupling with deserts and trade winds. The mechanisms recognized in this study suggest a way forward for understanding past and future changes of the GM in terms of its driven mechanisms. (orig.)

  3. Contrasting sedimentation patterns in two semi-enclosed mesotidal bays along the west and south coasts of Korea controlled by their orientation to the regional monsoon climate

    Science.gov (United States)

    Hong, Seok Hwi; Chun, Seung Soo; Chang, Tae Soo; Jang, Dae Geon

    2017-08-01

    Sedimentation patterns of tidal flats along the Korean west coast have long been known to be largely controlled by the monsoon climate. On the other hand, much less is known about the effect of the monsoon on sedimentation in coastal embayments with mouths of different geographic orientations. Good examples are Hampyeong and Yeoja bays along the west and south coasts, respectively. Both have narrow entrances, but their mouths open toward the northwest and the south, respectively. With mean tidal ranges of 3.46 and 3.2 m, respectively, the two bays experience similar tidal regimes and are hence excellent candidates to compare the effect of different exposure to the same regional monsoon climate on their respective sediment distribution patterns. The winter monsoon, in particular, is characterized by strong northwesterly winds that directly impact the west coast, but blow offshore along the south coast. For the purpose of this study, surficial sediment samples were collected from intertidal and subtidal flats of the two bays, both in summer and winter. Grain-size analyses were carried out by sieving (sand fraction) and Sedigraph (mud fraction). In the case of Yeoja Bay, the sediments consist mostly of mud (mean grain sizes of 5.4 to 8.8 phi). Seasonal changes are very subtle, the sediments being slightly coarser in summer when silt-dominated sediments are supplied by two streams to the northern parts of the bay in response to heavy rainfall. With the exception of the deeper tidal channels, Yeoja Bay is characterized by a thick mud blanket the year round, which is modulated by processes associated with the summer monsoon that predominantly blows from the east. Textural parameters suggest severely restricted sediment mixing on the subtidal and intertidal flats, the overall low energy situation preventing sands from reaching the tidal flats. The sediments of Hampyeong Bay, by contrast, are characterized by a distinct shoreward fining trend. Mean grain sizes average

  4. Similar speleothem δ18O signals indicating diverging climate variations in inland central Asia and monsoonal south Asia during the Holocene

    Science.gov (United States)

    Jin, Liya; Zhang, Xiaojian

    2017-04-01

    High-resolution and precisely dated speleothem oxygen isotope (δ18O) records from Asia have provided key evidence for past monsoonal changes. It is found that δ18O records of stalagmites from Kesang Cave (42°52'N, 81°45'E, Xinjiang, China) in inland central Asia were very similar to those from Qunf Cave (17°10'N, 54°18'E, southern Oman) in South Asia, shifting from light to heavy throughout the Holocene, which was regarded as a signal that strong Asian summer monsoon (ASM) may have intruded into the Kesang Cave site and/or adjacent areas in inland central Asia to produce heavy rainfall during the high insolation times (e.g. the early Holocene). However, this is in contrast to conclusions based on other Holocene proxy records and modeling simulations, showing a persistent wetting trend in arid central Asia during the Holocene with a dryer condition in the early Holocene and the wettest condition in the late Holocene. With an analysis of model-proxy data comparison, we revealed a possible physical mechanism responsible for the Holocene evolution of moisture/precipitation in Asian summer monsoon (ASM)-dominated regions and that in the inland central Asia. It is revealed that a recurrent circumglobal teleconnection (CGT) pattern in the summertime mid-latitude circulation of the Northern Hemisphere was closely related to the ASM and the climate of inland central Asia, acting as a bridge linking the ASM to insolation, high-latitude forcing (North Atlantic sea surface temperature (SST)), and low-latitude forcing (tropical Ocean SST). Also, the CGT influence speleothem δ18O values in South Asia via its effect on the amount of precipitation. In addition, the moisture source from the Indian Ocean is associated with relatively high δ18O values compared with that from the North Atlantic Ocean, leading to increased precipitation δ18O values. Hence, the CGT has probably been the key factor responsible for the in-phase relationship in speleothem δ18O values (Kesang Cave

  5. Sub-seasonal behaviour of Asian summer monsoon under a changing climate: assessments using CMIP5 models

    Science.gov (United States)

    Sooraj, K. P.; Terray, Pascal; Xavier, Prince

    2016-06-01

    Numerous global warming studies show the anticipated increase in mean precipitation with the rising levels of carbon dioxide concentration. However, apart from the changes in mean precipitation, the finer details of daily precipitation distribution, such as its intensity and frequency (so called daily rainfall extremes), need to be accounted for while determining the impacts of climate changes in future precipitation regimes. Here we examine the climate model projections from a large set of Coupled Model Inter-comparison Project 5 models, to assess these future aspects of rainfall distribution over Asian summer monsoon (ASM) region. Our assessment unravels a north-south rainfall dipole pattern, with increased rainfall over Indian subcontinent extending into the western Pacific region (north ASM region, NASM) and decreased rainfall over equatorial oceanic convergence zone over eastern Indian Ocean region (south ASM region, SASM). This robust future pattern is well conspicuous at both seasonal and sub-seasonal time scales. Subsequent analysis, using daily rainfall events defined using percentile thresholds, demonstrates that mean rainfall changes over NASM region are mainly associated with more intense and more frequent extreme rainfall events (i.e. above 95th percentile). The inference is that there are significant future changes in rainfall probability distributions and not only a uniform shift in the mean rainfall over the NASM region. Rainfall suppression over SASM seems to be associated with changes involving multiple rainfall events and shows a larger model spread, thus making its interpretation more complex compared to NASM. Moisture budget diagnostics generally show that the low-level moisture convergence, due to stronger increase of water vapour in the atmosphere, acts positively to future rainfall changes, especially for heaviest rainfall events. However, it seems that the dynamic component of moisture convergence, associated with vertical motion, shows a

  6. SUNYA Regional Climate Model Simulations of East Asia Summer Monsoon: Effects of Cloud Vertical Structure on the Surface Energy Balance

    Directory of Open Access Journals (Sweden)

    Wei Gong and Wei-Chyung Wang

    2007-01-01

    Full Text Available We used the State University of New York at Albany (SUNYA regional climate model to study the effect of cloud vertical distribution in affecting the surface energy balance of the East Asia summer monsoon (EASM. Simulations were conducted for the summers of 1988 and 1989, during which large contrast in the intra-seasonal cloud radiative forcing (CRF was observed at the top of the atmosphere. The model results indicate that both the high and low clouds are persistent throughout the summer months in both years. Because of large cloud water, low clouds significantly reduce the solar radiation flux reaching the surface, which nevertheless still dominate the surface energy balance, accounting for more than 50% of the surface heating. The low clouds also contribute significantly the downward longwave radiation to the surface with values strongly dependent on the cloud base temperature. The presence of low clouds effectively decreases the temperature and moisture gradients near surface, resulting in a substantial decrease in the sensible and latent heat fluxes from surface, which partially compensate the decrease of the net radiative cooling of the surface. For example, in the two days, May 8 and July 11 of 1988, the total cloud cover of 80% is simulated, but the respective low cloud cover (water was 63% (114 gm-2 and 22% (21 gm-2. As a result, the downward solar radiation is smaller by 161 Wm-2 in May 8. On the other hand, the cloud temperature was _ lower, yielding 56 Wm-2 smaller downward longwave radiation. The near surface temperature and gradient is more than _ smaller (and moisture gradient, leading to 21 and 81 Wm-2 smaller sensible heat and latent heat fluxes. It is also demonstrated that the model is capable to reproduce the intraseasonal variation of shortwave CRF, and catches the relationship between total cloud cover and SW CRF. The model results show the dominance of high cloud on the regional mean longwave CRF and low cloud on the intra

  7. Species richness, area and climate correlates

    DEFF Research Database (Denmark)

    Nogues, David Bravo; Bastos Araujo, Miguel

    2006-01-01

    affects: (1) the selection of climate variables entering a species richness model; and (2) the accuracy of models in predicting species richness in unsampled grid cells. Location Western Europe. Methods Models are developed for European plant, breeding bird, mammal and herptile species richness using...... seven climate variables. Generalized additive models are used to relate species richness, climate and area. Results We found that variation in the grid cell area was large (50 × 50 km: 8-3311 km2; 220 × 220: 193-55,100 km2), but this did not affect the selection of variables in the models. Similarly...... support the assumption that variation in near-equal area cells may be of second-order importance for models explaining or predicting species richness in relation to climate, although there is a possibility that drops in accuracy might increase with grid cell size. The results are, however, contingent...

  8. Reproductive performance of Matou goat under sub-tropical monsoonal climate of Central China.

    Science.gov (United States)

    Moaeen-ud-Din, M; Yand, L G; Chen, S L; Zhang, Z R; Xiao, J Z; Wen, Q Y; Dai, M

    2008-01-01

    The aim of the current study was to estimate reproductive parameters of Matou goat to evaluate a meat breed. Data on 2,560 kids from 1,197 kidding records of 638 does and on puberty of 546 females kids were collected from farmer household herds of Matou goats in six counties of Shiye city under Hubei Province in China. Statistical analyses on puberty, estrus, gestation length (GL), litter size (LS) and survival rate (SR) of kids at puberty were performed with software Genstat 5 (Release 3.1) by using descriptive statistics and regression models. The results showed that age at puberty of female kids was 108.4+/-19.1 days while estrus duration and cycle averaged 58.6+/-15.9 hours and 19.7+/-1.5 days respectively. Gestation length (GL) and litter size (LS) averaged 150+/-7.4 days and 2.14+/-0.9 respectively with 90.8% of survival rate (SR) of kids. GL was unassociated with parity, but delayed as LS increased. SR of kids at birth differed remarkably among parity 1 to 5, decreased significantly at parity 6 to 7, and then increased at 8th parity. In Matou goat over all twinning and triplet percentage was 45.4 percent and 16.3 percent whereas percentage of single birth was 27.4 percent. As twins and triplets birth rate is considerably higher in Matou goat so, this breed can be recommended to other parts of China and the world having similar climatic conditions.

  9. Forecasting Monsoon Precipitation Using Artificial Neural Networks

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper explores the application of Artificial Intelligent (AI) techniques for climate forecast. It pres ents a study on modelling the monsoon precipitation forecast by means of Artificial Neural Networks (ANNs). Using the historical data of the total amount of summer rainfall over the Delta Area of Yangtze River in China, three ANNs models have been developed to forecast the monsoon precipitation in the corre sponding area one year, five-year, and ten-year forward respectively. Performances of the models have been validated using a 'new' data set that has not been exposed to the models during the processes of model development and test. The experiment results are promising, indicating that the proposed ANNs models have good quality in terms of the accuracy, stability and generalisation ability.

  10. A climate change-induced threat to the ecological resilience of a subtropical monsoon evergreen broad-leaved forest in Southern China.

    Science.gov (United States)

    Zhou, Guoyi; Peng, Changhui; Li, Yuelin; Liu, Shizhong; Zhang, Qianmei; Tang, Xuli; Liu, Juxiu; Yan, Junhua; Zhang, Deqiang; Chu, Guowei

    2013-04-01

    Recent studies have suggested that tropical forests may not be resilient against climate change in the long term, primarily owing to predicted reductions in rainfall and forest productivity, increased tree mortality, and declining forest biomass carbon sinks. These changes will be caused by drought-induced water stress and ecosystem disturbances. Several recent studies have reported that climate change has increased tree mortality in temperate and boreal forests, or both mortality and recruitment rates in tropical forests. However, no study has yet examined these changes in the subtropical forests that account for the majority of China's forested land. In this study, we describe how the monsoon evergreen broad-leaved forest has responded to global warming and drought stress using 32 years of data from forest observation plots. Due to an imbalance in mortality and recruitment, and changes in diameter growth rates between larger and smaller trees and among different functional groups, the average DBH of trees and forest biomass have decreased. Sap flow measurements also showed that larger trees were more stressed than smaller trees by the warming and drying environment. As a result, the monsoon evergreen broad-leaved forest community is undergoing a transition from a forest dominated by a cohort of fewer and larger individuals to a forest dominated by a cohort of more and smaller individuals, with a different species composition, suggesting that subtropical forests are threatened by their lack of resilience against long-term climate change. © 2012 Blackwell Publishing Ltd.

  11. Radiolarian abundance - A monsoon proxy responding to the Earth`s orbital forcing: Inferences on the mid-Brunhes climate shift

    Digital Repository Service at National Institute of Oceanography (India)

    Gupta, S.M.

    stream_size 32348 stream_content_type text/plain stream_name Earth_Sci_India_2_1.pdf.txt stream_source_info Earth_Sci_India_2_1.pdf.txt Content-Encoding UTF-8 Content-Type text/plain; charset=UTF-8 Gupta http://www....earthscienceindia.info/Gupta.htm 1 of 8 1/28/2009 3:14 PM Earth Science India Vol.2 (I),January, 2009, pp. 1-20 http://www.earthscienceindia.info/ Radiolarian abundance - a monsoon proxy responding to the Earth’s orbital forcing: Inferences on the mid-Brunhes climate shift Shyam...

  12. Global monsoons in the mid-Holocene and oceanic feedback

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Z.; Kutzbach, J. [Center for Climatic Research, University of Wisconsin-Madison, 1225 W. Dayton Street, Madison, WI 53706 (United States); Harrison, S.P. [Max Planck Institute for Biogeochemistry, P.O. Box 100164, 07701 Jena (Germany); Otto-Bliesner, B. [National Center for Atmospheric Research, PO Box 3000, Boulder, CO 80307 (United States)

    2004-03-01

    The response of the six major summer monsoon systems (the North American monsoon, the northern Africa monsoon, the Asia monsoon, the northern Australasian monsoon, the South America monsoon and the southern Africa monsoon) to mid-Holocene orbital forcing has been investigated using a coupled ocean-atmosphere general circulation model (FOAM), with the focus on the distinct roles of the direct insolation forcing and oceanic feedback. The simulation result is also found to compare well with the NCAR CSM. The direct effects of the change in insolation produce an enhancement of the Northern Hemisphere monsoons and a reduction of the Southern Hemisphere monsoons. Ocean feedbacks produce a further enhancement of the northern Africa monsoon and the North American monsoon. However, ocean feedbacks appear to weaken the Asia monsoon, although the overall effect (direct insolation forcing plus ocean feedback) remains a strengthened monsoon. The impact of ocean feedbacks on the South American and southern African monsoons is relatively small, and therefore these regions, especially the South America, experienced a reduced monsoon regime compared to present. However, there is a strong ocean feedback on the northern Australian monsoon that negates the direct effects of orbital changes and results in a strengthening of austral summer monsoon precipitation in this region. A new synthesis is made for mid-Holocene paleoenvironmental records and is compared with the model simulations. Overall, model simulations produce changes in regional climates that are generally consistent with paleoenvironmental observations. (orig.)

  13. Is precipitation a predictor of mortality in Bangladesh? A multi-stratified analysis in a South Asian monsoon climate.

    Science.gov (United States)

    Burkart, Katrin; Kinney, Patrick

    2016-05-15

    While numerous studies have assessed the association between temperature and mortality in various locations, few have addressed the relationship between precipitation and mortality. Given the high amounts of rainfall in many tropical monsoon areas and the often seasonally pronounced differences, there might be a potentially strong impact on health outcomes and death. In this study, we investigated the association between precipitation and daily death counts in Bangladesh from 2003 to 2007 using regression models with a quasipoisson distribution adjusting for long-term time and seasonal trends, day of the month, age and perceived temperature. Effects were assessed for all ages, the elderly and by gender. During the dry season a sharp increase in death risk was found at very high precipitation amounts which are most likely to be cyclone-related. This cyclone effect was most pronounced for females at the immediate day with an increase of 18.7% (3.8-35.6%) in non-external cause mortality per mm precipitation above 5mm. At longer lags we found a negative association between precipitation and mortality indicating some kind of dry effect which was more pronounced for the elderly with a mortality increase of 4.4% (2.6-6.2%) per mm decrease in precipitation. During the rainy season, we observed a protective effect of rainfall which was strongest during periods of seasonally high equivalent temperatures with a decrease in mortality of 4.0% (2.3-5.6%) per mm increase in precipitation on the immediate day. The observed associations between precipitation and mortality differed by season, age and gender. Generally, a strong short-term increase in mortality was associated with cyclonic activity during the dry season, while ongoing low rainfall seemed to have an adverse impact at higher lags. During the rainy season, precipitation seemed to mitigate heat effects. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Orbitally-paced variations of water availability in the SE Asian Monsoon region following the Miocene Climate Transition

    Science.gov (United States)

    Heitmann, Emma O.; Ji, Shunchuan; Nie, Junsheng; Breecker, Daniel O.

    2017-09-01

    Middle Miocene Earth had several boundary conditions similar to those predicted for future Earth including similar atmospheric pCO2 and substantial Antarctic ice cover but no northern hemisphere ice sheets. We describe a 12 m outcrop of the terrestrial Yanwan Section in the Tianshui Basin, Gansu, China, following the Miocene Climate Transition (13.9-13.7 Ma). It consists of ∼25 cm thick CaCO3-cemented horizons that overprint siltstones every ∼1 m. We suggest that stacked soils developed in siltstones under a seasonal climate with a fluctuating water table, evidenced by roots, clay films, mottling, presence of CaCO3 nodules, and stacked carbonate nodule δ13 C and δ18 O profiles that mimic modern soils. We suggest that the CaCO3-cemented horizons are capillary-fringe carbonates that formed in an arid climate with a steady water table and high potential evapotranspiration rates (PET), evidenced by sharp upper and basal contacts, micrite, sparite, and root-pore cements. The CaCO3 of the cemented horizons and the carbonate nodules have similar mean δ18 O and δ13 C values but the cements have significantly smaller variance in δ13 C and δ18 O values and a different δ18 O versus δ13 C slope, supporting the conclusion that these carbonates are from different populations. The magneto-stratigraphic age model indicates obliquity pacing of the arid conditions required to form the CaCO3-cemented horizons suggesting an orbital control on water availability. We suggest two possible drivers for the obliquity pacing of arid conditions: 1) variability in the cross-equatorial pressure gradient that controls summer monsoon (ASM) strength and is influenced by obliquity-paced variations of Antarctic ice volume and 2) variability in Western Pacific Ocean-East Asian continent pressure gradient controlled by the 25-45°N meridional insolation gradient. We also suggest that variations in aridity were influenced by variations in PET and sensible heating of the regional land

  15. Month-to-month variability of Indian summer monsoon rainfall in 2016: role of the Indo-Pacific climatic conditions

    Science.gov (United States)

    Chowdary, Jasti S.; Srinivas, G.; Du, Yan; Gopinath, K.; Gnanaseelan, C.; Parekh, Anant; Singh, Prem

    2018-03-01

    Indian summer monsoon (ISM) rainfall during 2016 exhibited a prominent month-to-month fluctuations over India, with below normal rainfall in June and August and above normal rainfall in July. The factors determining the month-to-month fluctuations in ISM rainfall during 2016 are investigated with main focus on the Indo-Pacific climatic anomalies. Warm sea surface temperature (SST) anomalies associated with super El Niño 2015 disappeared by early summer 2016 over the central and eastern Pacific. On the other hand, negative Indian Ocean dipole (IOD) like SST anomaly pattern over the equatorial Indian Ocean and anomalous anticyclonic circulation over the western North Pacific (WNP) are reported in summer 2016 concurrently with decaying El Niño/developing La Niña phase. Observations revealed that the low rainfall over central north India in June is due to moisture divergence caused by the westward extension of ridge corresponding to WNP anticyclone and subsidence induced by local Hadley cell partly related to negative IOD. Low level convergence of southeasterly wind from Bay of Bengal associated with weak WNP anticyclone and northwesterly wind corresponding to anticyclonic circulation over the northwest India remarkably contributed to positive rainfall in July over most of the Indian subcontinent. While reduced rainfall over the Indian subcontinent in August 2016 is associated with the anomalous moisture transport from ISM region to WNP region, in contrast to July, due to local cyclogenesis corroborated by number of tropical cyclones in the WNP. In addition to this, subsidence related to strong convection supported by cyclonic circulation over the WNP also resulted in low rainfall over the ISM region. Coupled General Circulation model sensitivity experiments confirmed that strong convective activities associated with cyclonic circulation over the WNP is primarily responsible for the observed negative ISM rainfall anomalies in August 2016. It is noted that the Indo

  16. Reliability of shell carbon isotope composition of different land snail species as a climate proxy: A case study in the monsoon region of China

    Science.gov (United States)

    Bao, Rui; Sheng, Xuefen; Teng, Henry H.; Ji, Junfeng

    2018-05-01

    Carbon isotope compositions of land snail shells (δ13Cshell) are shown to be indicative of local climate conditions. However, it is largely unknown how the responses of δ13Cshell to climatic factors changes amongst different species. In this study, we collected 3 species of land snail shells across the East Asian monsoon region of China to explore the overall relationship between δ13Cshell as well as the response of individual species to the regional climate. Results show that, whereas all species collectively can provide a consensus relation between δ13Cshell and local climatic factors such as temperature and precipitation; the response of individual species to the fluctuations of these factors is not uniform. Specifically, while the southerly species Bradybaena similaris exhibits robust δ13Cshell - mean precipitation correlation in both linearity and sensitivity, a common northerly species, Cathaica fasciola, only finds limited utility as a climate indicator, particularly for precipitation. Meanwhile, the south-central species Acusta ravida appears to be able to faithfully record past climate conditions despite showing a wider distribution and a broader habitat. Such species-dependent nature in the relations between δ13Cshell and local climatic factors can be attributed to the effect of ingested carbonate and variations in eco-physiological factors of different species, and is expected to be widespread, suggesting the need to be taken into consideration for future studies.

  17. Why do global climate models struggle to represent low-level clouds in the West African summer monsoon?

    Science.gov (United States)

    Knippertz, Peter; Hannak, Lisa; Fink, Andreas H.; Kniffka, Anke; Pante, Gregor

    2017-04-01

    Climate models struggle to realistically represent the West African monsoon (WAM), which hinders reliable future projections and the development of adequate adaption measures. Low-level clouds over southern West Africa (5-10°N, 8°W-8°E) during July-September are an integral part of the WAM through their effect on the surface energy balance and precipitation, but their representation in climate models has so far received little attention. These clouds usually form during the night near the level of the nocturnal low-level jet ( 950 hPa), thicken and spread until the mid-morning ( 09 UTC), and then break up and rise in the course of the day, typically to about 850 hPa. The low thermal contrast to the surface and the frequent presence of obscuring higher-level clouds make detection of the low-level clouds from space rather challenging. Here we use 30 years of output from 18 models participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5) as well as 20 years of output from 8 models participating in the Year of Tropical Convection (YoTC) experiments to identify cloud biases and their causes. A great advantage of the YoTC dataset is the 6-hourly output frequency, which allows an analysis of the diurnal cycle, and the availability of temperature and moisture tendencies from parameterized processes such as convection, radiation and boundary-layer turbulence. A comparison to earlier analyses based on CMIP3 output reveals rather limited improvements with regard to the represenation of low-level cloud and winds. Compared to ERA-Interim re-analyses, which shows satisfactory agreement with surface observations, many of the CMIP5 and YoTC models still have large biases in low-level cloudiness of both signs and a tendency to too high elevation and too weak diurnal cycles. At the same time, these models tend to have too strong low-level jets, the impact of which is unclear due to concomitant effects on temperature and moisture advection as well as turbulent

  18. Individual species-area relationship of woody plant communities in a heterogeneous subtropical monsoon rainforest.

    Science.gov (United States)

    Tsai, Cheng-Han; Lin, Yi-Ching; Wiegand, Thorsten; Nakazawa, Takefumi; Su, Sheng-Hsin; Hsieh, Chih-Hao; Ding, Tzung-Su

    2015-01-01

    The spatial structure of species richness is often characterized by the species-area relationship (SAR). However, the SAR approach rarely considers the spatial variability of individual plants that arises from species interactions and species' habitat associations. Here, we explored how the interactions of individual plants of target species influence SAR patterns at a range of neighborhood distances. We analyzed the data of 113,988 woody plants of 110 species from the Fushan Forest Dynamics Plot (25 ha), northern Taiwan, which is a subtropical rainforest heavily influenced by typhoons. We classified 34 dominant species into 3 species types (i.e., accumulator, repeller, or no effect) by testing how the individual species-area relationship (i.e., statistics describing how neighborhood species richness changes around individuals) of target species departs (i.e., positively, negatively, or with no obvious trend) from a null model that accounts for habitat association. Deviation from the null model suggests that the net effect of species' interactions increases (accumulate) or decreases (repel) neighborhood species richness. We found that (i) accumulators were dominant at small interaction distances (30 m); (iii) repellers were rarely detected; and (iv) large-sized and abundant species tended to be accumulators. The findings suggest that positive species interactions have the potential to accumulate neighborhood species richness, particularly through size- and density-dependent mechanisms. We hypothesized that the frequently disturbed environment of this subtropical rainforest (e.g., typhoon-driven natural disturbances such as landslides, soil erosion, flooding, and windthrow) might create the spatial heterogeneity of species richness and promote positive species interactions.

  19. Possible connection between the East Asian summer monsoon and a swing of the haze-fog-prone area in eastern China

    Science.gov (United States)

    Liu, Qian; Cao, Ziqi; Sheng, Lifang; Diao, Yina; Wang, Wencai; Zhou, Yang; Qiu, Jingyi

    2018-05-01

    The summer monsoon has recently been hypothesized to influence haze-fog events over China, but the detailed processes involved have yet to be determined. In the present study, we found that the haze-fog-prone area swings over eastern China during boreal summer (May to September), coinciding with the movement of the subtropical monsoon convergence belt (hereinafter referred to simply as the "convergence belt"). Further investigation showed that the convergence belt modulates the spatial distribution of the haze-fog-prone area by altering the regional atmospheric conditions. When the warm and wet summer monsoon air mass pushes northwards and meets with cold air, a frontal zone (namely, the convergence belt) forms. The ascent of warm and wet air along the front strengthens the atmospheric stability ahead of the frontal zone, while the descent of cold and dry air weakens the vertical diffusion at the same place. These processes result in an asymmetric distribution of haze-fog along the convergence belt. Based on the criterion of absolute stability and downdraft, these atmospheric conditions favorable for haze-fog are able to identify 57-79% of haze-fog-prone stations, and the anticipation accuracy is 61-71%. After considering the influence of air pollutants on haze-fog occurrence, the anticipation accuracy rises to 78-79%. Our study reveals a connection between local haze-fog weather phenomena and regional atmospheric conditions and large-scale circulation, and demonstrates one possible mechanism for how the summer monsoon influences the distribution of haze-fog in eastern China.

  20. Non-stationary analysis of dry spells in monsoon season of Senegal River Basin using data from Regional Climate Models (RCMs)

    Science.gov (United States)

    Giraldo Osorio, J. D.; García Galiano, S. G.

    2012-07-01

    SummaryThe Senegal River Basin, located in West Africa, has been affected by several droughts since the end of the 1960s. In its valley, which is densely populated and highly vulnerable to climate variability and water availability, agricultural activities provide the livelihood for thousands of people. Increasing the knowledge about plausible trends of drought events will allow to improve the adaptation and mitigation measures in order to build "adaptive capacity" to climate change in West Africa. An innovative methodology for the non-stationary analysis of droughts events, which allows the prediction of regional trends associated to several return periods, is presented. The analyses were based on Regional Climate Models (RCMs) provided by the European ENSEMBLES project for West Africa, together with observed data. A non-stationary behaviour of the annual series of maximum length of dry spells (AMDSL) in the monsoon season is reflected in temporal changes in mean and variance. The non-stationary nature of hydrometeorological series, due to climate change and anthropogenic activities, is the main criticism to traditional frequency analysis. Therefore, in this paper, the modelling tool GAMLSS (Generalized Additive Models for Location, Scale and Shape), is applied to develop regional probability density functions (pdfs) fitted to AMDSL series for the monsoon season in the Senegal River Basin. The skills of RCMs in the representation of maximum length of dry spells observed for the period 1970-1990, are evaluated considering observed data. Based on the results obtained, a first selection of the RCMs with which to apply GAMLSS to the AMDSL series identified, for the time period 1970-2050, is made. The results of GAMLSS analysis exhibit divergent trends, with different value ranges for parameters of probability distributions being detected. Therefore, in the second stage of the paper, regional pdfs are constructed using bootstrapping distributions based on probabilistic

  1. Role of Ocean Initial Conditions to Diminish Dry Bias in the Seasonal Prediction of Indian Summer Monsoon Rainfall: A Case Study Using Climate Forecast System

    Science.gov (United States)

    Koul, Vimal; Parekh, Anant; Srinivas, G.; Kakatkar, Rashmi; Chowdary, Jasti S.; Gnanaseelan, C.

    2018-03-01

    Coupled models tend to underestimate Indian summer monsoon (ISM) rainfall over most of the Indian subcontinent. Present study demonstrates that a part of dry bias is arising from the discrepancies in Oceanic Initial Conditions (OICs). Two hindcast experiments are carried out using Climate Forecast System (CFSv2) for summer monsoons of 2012-2014 in which two different OICs are utilized. With respect to first experiment (CTRL), second experiment (AcSAL) differs by two aspects: usage of high-resolution atmospheric forcing and assimilation of only ARGO observed temperature and salinity profiles for OICs. Assessment of OICs indicates that the quality of OICs is enhanced due to assimilation of actual salinity profiles. Analysis reveals that AcSAL experiment showed 10% reduction in the dry bias over the Indian land region during the ISM compared to CTRL. This improvement is consistently apparent in each month and is highest for June. The better representation of upper ocean thermal structure of tropical oceans at initial stage supports realistic upper ocean stability and mixing. Which in fact reduced the dominant cold bias over the ocean, feedback to air-sea interactions and land sea thermal contrast resulting better representation of monsoon circulation and moisture transport. This reduced bias of tropospheric moisture and temperature over the Indian land mass and also produced better tropospheric temperature gradient over land as well as ocean. These feedback processes reduced the dry bias in the ISM rainfall. Study concludes that initializing the coupled models with realistic OICs can reduce the underestimation of ISM rainfall prediction.

  2. Simulation of the anthropogenic aerosols over South Asia and their effects on Indian summer monsoon

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Zhenming [Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Beijing (China); National Climate Center, Beijing (China); Graduate University of Chinese Academy of Sciences, Beijing (China); Kang, Shichang [Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Beijing (China); Chinese Academy of Sciences, State Key Laboratory of Cryospheric Science, Lanzhou (China); Zhang, Dongfeng [Shanxi Meteorological Bureau, Taiyuan (China); Zhu, Chunzi [Nanjing University of Information Science Technology, College of Atmospheric Science, Nanjing (China); Wu, Jia; Xu, Ying [National Climate Center, Beijing (China)

    2011-05-15

    A regional climate model coupled with a chemistry-aerosol model is employed to simulate the anthropogenic aerosols including sulfate, black carbon and organic carbon and their direct effect on climate over South Asia. The model is driven by the NCAR/NCEP re-analysis data. Multi-year simulations with half, normal and double emission fluxes are conducted. Results show that the model performs well in reproducing present climate over the region. Simulations of the aerosol optical depth and surface concentration of aerosols are also reasonable although to a less extent. The negative radiative forcing is found at the top of atmosphere and largely depended on emission concentration. Surface air temperature decreases by 0.1-0.5 C both in pre-monsoon and monsoon seasons. The range and intensity of cooling areas enlarge while aerosol emission increases. Changes in precipitation are between -25 and 25%. Different diversifications of rainfall are showed with three emission scenarios. The changes of precipitation are consistent with varieties of monsoon onset dates in pre-monsoon season. In the regions of increasing precipitation, monsoon onset is advanced and vice versa. In northeast India and Myanmar, aerosols lead the India summer monsoon onset advancing 1-2 pentads, and delaying by 1-2 pentads in central and southeast India. These changes are mainly caused by the anomaly of local Hadley circulations and enhancive precipitation. Tibetan Plateau played a crucial role in the circulation changes. (orig.)

  3. Seasonal phytoplankton blooms associated with monsoonal influences and coastal environments in the sea areas either side of the Indochina Peninsula

    Science.gov (United States)

    Tang, Dan Ling; Kawamura, Hiroshi; Shi, Ping; Takahashi, Wataru; Guan, Lei; Shimada, Teruhisa; Sakaida, Futoki; Isoguchi, Osamu

    2006-03-01

    The Gulf of Thailand (GoT) is a semienclosed sea on the west and southwest side of the Indochina Peninsula and connects with the near-coastal waters of the South China Sea (SCS) on the east and northeast side of the Malay Peninsula. The objective of the present study is to understand dynamic features of the phytoplankton biology in the GoT and the nearby SCS, on both sides of the Indochina Peninsula, using remote-sensing measurements of chlorophyll-a (Chl a), sea surface temperature (SST), and surface vector winds obtained during the period from September 1997 to March 2003. Results show that seasonal variations of the phytoplankton blooms are primarily controlled by the monsoonal winds and related coastal environments. The GoT and the near-coastal SCS have a peak in the averaged monthly Chl a in December and January, which is associated with the winter northeaster monsoon. The near-coastal SCS have another big peak in the averaged monthly Chl a in summer (July to September), which is associated with the summer southwest monsoon. The offshore bloom in the GoT occurs in its southern part and enhances the December-January peak of averaged monthly Chl a. By contrast, the offshore bloom in the nearby SCS is observed northeast of the Peninsula, and represents the primary source of the July-September peak Chl a. Here the coastal upwelling associated with the offshore Ekman transport caused by the coastal surface winds parallel to the Vietnam east coast gives physical conditions favorable to the development of offshore phytoplankton blooms. The Mekong River discharge waters flow in different directions, depending on the monsoon winds, and contributes to seasonal blooms on both sides of the Peninsula.

  4. Relationship between summer monsoon rainfall and cyclogenesis ...

    Indian Academy of Sciences (India)

    relationship between Indian Ocean Dipole Mode. Index (IODMI) and the ... 2013) in the cyclogenesis over north Indian Ocean ..... Indian summer monsoon; J. Climate 17 3141–3155. ... Murakami H, Wang B and Kitoh A 2011 Future change.

  5. Assessment of the performance of CORDEX-South Asia experiments for monsoonal precipitation over the Himalayan region during present climate: part I

    Science.gov (United States)

    Ghimire, S.; Choudhary, A.; Dimri, A. P.

    2018-04-01

    Analysis of regional climate simulations to evaluate the ability of 11 Coordinated Regional Climate Downscaling Experiment in South Asia experiments (CORDEX-South Asia) along with their ensemble to produce precipitation from June to September (JJAS) over the Himalayan region have been carried out. These suite of 11 combinations come from 6 regional climate models (RCMs) driven with 10 initial and boundary conditions from different global climate models and are collectively referred here as 11 CORDEX South Asia experiments. All the RCMs use a similar domain and are having similar spatial resolution of 0.44° ( 50 km). The set of experiments are considered to study precipitation sensitivity associated with the Indian summer monsoon (ISM) over the study region. This effort is made as ISM plays a vital role in summertime precipitation over the Himalayan region which acts as driver for the sustenance of habitat, population, crop, glacier, hydrology etc. In addition, so far the summer monsoon precipitation climatology over the Himalayan region has not been studied with the help of CORDEX data. Thus this study is initiated to evaluate the ability of the experiments and their ensemble in reproducing the characteristics of summer monsoon precipitation over Himalayan region, for the present climate (1970-2005). The precipitation climatology, annual precipitation cycles and interannual variabilities from each simulation have been assessed against the gridded observational dataset: Asian Precipitation-Highly Resolved Observational Data Integration Towards the Evaluation of Water Resources for the given time period. Further, after the selection of the better performing experiment the frequency distribution of precipitation was also studied. In this study, an approach has also been made to study the degree of agreement among individual experiments as a way to quantify the uncertainty among them. The experiments though show a wide variation among themselves and individually over

  6. Mapping urban climate zones and quantifying climate behaviors - An application on Toulouse urban area (France)

    Energy Technology Data Exchange (ETDEWEB)

    Houet, Thomas, E-mail: thomas.houet@univ-tlse2.fr [GEODE UMR 5602 CNRS, Universite de Toulouse, 5 allee Antonio Machado, 31058 Toulouse Cedex (France); Pigeon, Gregoire [Centre National de Recherches Meteorologiques, Meteo-France/CNRM-GAME, 42 avenue Coriolis, 31057 Toulouse Cedex (France)

    2011-08-15

    Facing the concern of the population to its environment and to climatic change, city planners are now considering the urban climate in their choices of planning. The use of climatic maps, such Urban Climate Zone-UCZ, is adapted for this kind of application. The objective of this paper is to demonstrate that the UCZ classification, integrated in the World Meteorological Organization guidelines, first can be automatically determined for sample areas and second is meaningful according to climatic variables. The analysis presented is applied on Toulouse urban area (France). Results show first that UCZ differentiate according to air and surface temperature. It has been possible to determine the membership of sample areas to an UCZ using landscape descriptors automatically computed with GIS and remote sensed data. It also emphasizes that climate behavior and magnitude of UCZ may vary from winter to summer. Finally we discuss the influence of climate data and scale of observation on UCZ mapping and climate characterization. - Highlights: > We proposed a method to map Urban Climate Zones and quantify their climate behaviors. > UCZ is an expert-based classification and is integrated in the WMO guidelines. > We classified 26 sample areas and quantified climate behaviors in winter/summer. > Results enhance urban heat islands and outskirts are surprisingly hottest in summer. > Influence of scale and climate data on UCZ mapping and climate evaluation is discussed. - This paper presents an automated approach to classify sample areas in a UCZ using landscape descriptors and demonstrate that climate behaviors of UCZ differ.

  7. Impact of Rice Paddy Areas Decrease on Local Climate over Taiwan

    Science.gov (United States)

    Lo, M. H.; Wen, W. H.; Chen, C. C.

    2014-12-01

    Agricultural irrigation practice is one of the important anthropogenic processes in the land surface modeling. Irrigation can decrease local surface temperature with alternating surface energy partitioning. Rice paddy is the major food crop in Asian monsoon region and rice is grown under flooded conditions during the growing season; hence, the rice paddy can be considered as an open water body, which has more impacts on the surface energy budget than other cropland does. In this study, we explore how the rice paddy area changes affect Taiwan's regional climate from both observational data and numerical modeling exercise. The Weather Research and Forecasting (WRF) model is utilized to explore impacts of rice paddy area changes on the regional climate, and energy and water budget changes. In addition, temperature datasets from six automatic weather stations in the northern Taiwan and two stations in the southern Taiwan are analyzed in this study to explore how the Daily Temperature Range (DTR) changes with the decreased rice paddy areas. Previous studies show that due to the urban heat island effect, aerosol direct and indirect effects, and global warming, the DTR has decreased in the past 4 decades observed from most of the weather stations around Taiwan. However, the declined rice paddy area may increase the DTR with higher Bowen ratio during the daytime. Preliminary results show that DTR is decreased in weather stations near the urban area, but increased in weather stations near fallow areas in the past 20 years. It shows that different land use changes may have opposite impacts on local and regional climate.

  8. Riverine CO2 supersaturation and outgassing in a subtropical monsoonal mountainous area (Three Gorges Reservoir Region) of China

    Science.gov (United States)

    Li, Siyue; Ni, Maofei; Mao, Rong; Bush, Richard T.

    2018-03-01

    Rivers are an important source of CO2 to the atmosphere, however, mountainous rivers and streams with high emission rates are not well studied particularly in China. We report the first detailed investigation on monsoonal mountainous rivers in the Three Gorges Reservoir (TGR) region, with a focus on the riverine CO2 partial pressure (pCO2), CO2 degassing and their potential controls. The pCO2 levels ranged from 50 to 6019 μatm with averages of 1573 (SD. ±1060) in dry Autumn and 1276 (SD. ±1166) μatm in wet Summer seasons. 94% of samples were supersaturated with CO2 with respect to the atmospheric equilibrium (410 μatm). Monsoonal precipitation controlled pCO2 seasonality, with both the maximal and minimal levels occurring in the wet season, and showing the overall effects of dilution. Riverine pCO2 could be predicted better in the dry season using pH, DO% and DTP, whereas pH and DOC were better predictors in the wet season. We conclude that in-situ respiration of allochthonous organic carbon, rather than photosynthesis, resulted in negative relationships between pCO2 and DO and pH, and thus CO2 supersaturation. Photosynthetic primary production was effectively limited by rapid flow velocity and short residence time. The estimated water-to-air CO2 emission rate in the TGR rivers was 350 ± 319 in the Autumn and lower, yet more variable at 326 ± 439 mmol/m2/d in Summer. Our calculated CO2 areal fluxes were in the upper-level magnitude of published data, demonstrating the importance of mountainous rivers and streams as a global greenhouse gas source, and urgency for more detailed studies on CO2 degassing, to address a global data gap for these environments.

  9. The monsoon system: Land–sea breeze or the ITCZ?

    Indian Academy of Sciences (India)

    Sulochana Gadgil

    2018-01-27

    Jan 27, 2018 ... ocean contrast is one of the main drivers of the monsoon rainfall, in the 5th Assessment Report of the Inter-governmental Panel on Climate Change. (IPCC Climate Change 2013), the likely enhance- ment of monsoon rainfall has been attributed to increased land–sea contrast, and more abundant.

  10. Temporal derivative of Total Solar Irradiance and anomalous Indian summer monsoon: An empirical evidence for a Sun–climate connection

    Digital Repository Service at National Institute of Oceanography (India)

    Agnihotri, R.; Dutta, K.; Soon, W.

    and Solar-Terrestrial Physics 73 (2011) 1980–1987 1985 a factor of 5–10 times larger than the top of the atmosphere forcing. Several other researchers have also carefully evaluated and highlighted the complex pathways and processes that may be involved... irradiance and the variance of ENSO variability. Hence, a meaningful study of Sun– climate relation must involve not only careful consideration of the solar forcing factors, but also the proper measures for the local and regional climatic responses...

  11. Investigating the impact of global climatic and landuse changes on groundwater resources in hard rock areas of South India

    Science.gov (United States)

    Ferrant, S.; Perrin, J.; Marechal, J.; Dewandel, B.; Aulong, S.; Ahmed, S.

    2010-12-01

    In most parts of India, and particularly in South India, groundwater levels are hazardously declining, while agricultural groundwater use is increasing. The current issue is to address the probable evolution of water table levels in relation with climate and agricultural changes. The aim of the SHIVA-ANR project (http://www.shiva-anr.org) is to provide some indicators of the water availability at the village scale to evaluate the vulnerability of farmers facing global changes. This study focuses on a particularly water stressed semi-arid area of South India characterized by hard rock geology with naturally low recharge capacity and limited surface water availability. The study catchment is located in the agricultural area of the Kudaliar river watershed (980km^2) located 50 km north of Hyderabad, India. It is composed of about 120 villages. Socio economic surveys have been carried out at the village scale to evaluate the present socio-economic situation of farmers. It also provides more details on various cultural and irrigation practices at this scale. The landuse has been evaluated by remote sensing with two satellite images, one after monsoon (October 2009), and the other during dry season (March 2010). Groundwater-irrigated rice paddies represent about 10% of the area, whereas rainfed crop (corn and cotton) represent about 45%. Numerous small tanks (reservoir) situated on the river network define a water harvesting system of 2% of the catchment area which captures surface runoff during monsoon. No discharges data are available at the outlet, as the river is dry most of the year. A hydro-geological survey has been carried out to provide a map of aquifer thickness and the general state of the groundwater level before and after monsoon. The Soil Water Assessment Tool model (SWAT) has been calibrated to assess the water budget of the agricultural catchment under present conditions. Soil parameters calibration is made first on seasonal groundwater recharge for

  12. Impact assessment of El Nino and La Nina episodes on local/regional monsoon rainfall in India

    International Nuclear Information System (INIS)

    Singh, Sureuder; Rao, V.U.M.; Shigh, Diwan

    2002-08-01

    Large scale atmospheric circulation's and climatic anomalies have been shown to have a significant impact on seasonal weather over many parts of the world. In the present paper an attempt has been made to examine regional monsoon dynamics in relation with El Nino and La Nina episodes. The investigation was earned out for the meteorological sub- division's comprising the areas of Haryana, Delhi and Chandigarh in India. The monthly monsoon rainfall data of different locations in the region and corresponding data on El Nino and La Nina episodes for the period of 30 years (1970-99) were used for this investigation. During the El Nino episodes, various locations experienced excess rainfall in monsoon ranged between 11 and 22 percent. Under the influence of La Nina episodes, the probability of excess monsoon rainfall at different locations in the sub-division ranged between 13 and 25 percent. However, many locations viz., Hisar, Bhiwani, Gurgaon, Delhi and Chandigarh received deficient monsoon rainfall which was contrary to the global belief of the association between SST anomalies and rainfall distribution. No significant association was observed between El Nino and La Nina and monsoon rainfall at different locations in the entire sub-division. However, there was a strong relationship between these SST anomalies and all India monsoon rainfall over the period under study (1970-99). (author)

  13. Monsoon and cyclone induced wave climate over the near shore waters off Puduchery, south western Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Glejin, J.; SanilKumar, V.; Nair, T.M.B.

    . Reanalysis data, NCEP / NCAR (Kalnay et al. 1996), provided by the NOAA-CIRES Climate Diagnostics Center, Boulder, Colorado at http://www.cdc.noaa.gov/ at 10 m height with a temporal resolution of 6 hour intervals is used to analyze the wind pattern...

  14. Climate change under a scenario near 1.5 °C of global warming: monsoon intensification, ocean warming and steric sea level rise

    Directory of Open Access Journals (Sweden)

    J. Schewe

    2011-03-01

    Full Text Available We present climatic consequences of the Representative Concentration Pathways (RCPs using the coupled climate model CLIMBER-3α, which contains a statistical-dynamical atmosphere and a three-dimensional ocean model. We compare those with emulations of 19 state-of-the-art atmosphere-ocean general circulation models (AOGCM using MAGICC6. The RCPs are designed as standard scenarios for the forthcoming IPCC Fifth Assessment Report to span the full range of future greenhouse gas (GHG concentrations pathways currently discussed. The lowest of the RCP scenarios, RCP3-PD, is projected in CLIMBER-3α to imply a maximal warming by the middle of the 21st century slightly above 1.5 °C and a slow decline of temperatures thereafter, approaching today's level by 2500. We identify two mechanisms that slow down global cooling after GHG concentrations peak: The known inertia induced by mixing-related oceanic heat uptake; and a change in oceanic convection that enhances ocean heat loss in high latitudes, reducing the surface cooling rate by almost 50%. Steric sea level rise under the RCP3-PD scenario continues for 200 years after the peak in surface air temperatures, stabilizing around 2250 at 30 cm. This contrasts with around 1.3 m of steric sea level rise by 2250, and 2 m by 2500, under the highest scenario, RCP8.5. Maximum oceanic warming at intermediate depth (300–800 m is found to exceed that of the sea surface by the second half of the 21st century under RCP3-PD. This intermediate-depth warming persists for centuries even after surface temperatures have returned to present-day values, with potential consequences for marine ecosystems, oceanic methane hydrates, and ice-shelf stability. Due to an enhanced land-ocean temperature contrast, all scenarios yield an intensification of monsoon rainfall under global warming.

  15. Modeling sensitivity study of the possible impact of snow and glaciers developing over Tibetan Plateau on Holocene African-Asian summer monsoon climate

    Directory of Open Access Journals (Sweden)

    L. Jin

    2009-08-01

    Full Text Available The impacts of various scenarios of a gradual snow and glaciers developing over the Tibetan Plateau on climate change in Afro-Asian monsoon region and other regions during the Holocene (9 kyr BP–0 kyr BP are studied by using the Earth system model of intermediate complexity, CLIMBER-2. The simulations show that the imposed snow and glaciers over the Tibetan Plateau in the mid-Holocene induce global summer temperature decreases over most of Eurasia but in the Southern Asia temperature response is opposite. With the imposed snow and glaciers, summer precipitation decreases strongly in North Africa and South Asia as well as northeastern China, while it increases in Southeast Asia and the Mediterranean. For the whole period of Holocene (9 kyr BP–0 kyr BP, the response of vegetation cover to the imposed snow and glaciers cover over the Tibetan Plateau is not synchronous in South Asia and in North Africa, showing an earlier and a more rapid decrease in vegetation cover in North Africa from 9 kyr BP to 6 kyr BP while it has only minor influence on that in South Asia until 5 kyr BP. The precipitation decreases rapidly in North Africa and South Asia while it decreases slowly or unchanged during 6 kyr BP to 0 kyr BP with imposed snow and glacier cover over the Tibetan Plateau. The different scenarios of snow and glacier developing over the Tibetan Plateau would result in differences in variation of temperature, precipitation and vegetation cover in North Africa, South Asia and Southeast Asia. The model results suggest that the development of snow and ice cover over Tibetan Plateau represents an additional important climate feedback, which amplify orbital forcing and produces a significant synergy with the positive vegetation feedback.

  16. Inadvertent weather modification urban areas - lessons for global climate change

    Energy Technology Data Exchange (ETDEWEB)

    Changnon, S A [Illinois State Water Survey, Champaign, IL (USA)

    1992-05-01

    Large metropolitan areas in North America, home to 65% of the USA's population, have created major changes in their climates over the past 150 years. The rate and amount of the urban climate change approximate those being predicted globally using climate models. Knowledge of urban weather and climate modification holds lessons for the global climate change issue. First, adjustments to urban climate changes can provide guidance for adjusting to global change. A second lesson relates to the difficulty but underscores the necessity of providing scientifically credible proof of change within the noise of natural climatic variability. The evolution of understanding about how urban conditions influence weather reveals several unexpected outcomes, particularly relating to precipitation changes. These suggest that similar future surprises can be expected in a changed global climate, a third lesson. In-depth studies of how urban climate changes affected the hydrologic cycle, the regional economy, and human activities were difficult because of data problems, lack of impact methodology, and necessity for multidisciplinary investigations. Similar impact studies for global climate change will require diverse scientific talents and funding commitments adequate to measure the complexity of impacts and human adjustments. Understanding the processes whereby urban areas and other human activities have altered the atmosphere and changed clouds and precipitation regionally appears highly relevant to the global climate-change issue. Scientific and governmental policy development needs to recognize an old axiom that became evident in the studies of inadvertent urban and regional climate change and their behavioural implications: Think globally but act locally. Global climate change is an international issue, and the atmosphere must be treated globally. But the impacts and the will to act and adjust will occur regionally.

  17. Inadvertent weather modification urban areas - lessons for global climate change

    International Nuclear Information System (INIS)

    Changnon, S.A.

    1992-01-01

    Large metropolitan areas in North America, home to 65% of the USA's population, have created major changes in their climates over the past 150 years. The rate and amount of the urban climate change approximate those being predicted globally using climate models. Knowledge of urban weather and climate modification holds lessons for the global climate change issue. First, adjustments to urban climate changes can provide guidance for adjusting to global change. A second lesson relates to the difficulty but underscores the necessity of providing scientifically credible proof of change within the noise of natural climatic variability. The evolution of understanding about how urban conditions influence weather reveals several unexpected outcomes, particularly relating to precipitation changes. These suggest that similar future surprises can be expected in a changed global climate, a third lesson. In-depth studies of how urban climate changes affected the hydrologic cycle, the regional economy, and human activities were difficult because of data problems, lack of impact methodology, and necessity for multidisciplinary investigations. Similar impact studies for global climate change will require diverse scientific talents and funding commitments adequate to measure the complexity of impacts and human adjustments. Understanding the processes whereby urban areas and other human activities have altered the atmosphere and changed clouds and precipitation regionally appears highly relevant to the global climate-change issue. Scientific and governmental policy development needs to recognize an old axiom that became evident in the studies of inadvertent urban and regional climate change and their behavioural implications: Think globally but act locally. Global climate change is an international issue, and the atmosphere must be treated globally. But the impacts and the will to act and adjust will occur regionally

  18. Climate change and the water cycle in newly irrigated areas.

    Science.gov (United States)

    Abrahão, Raphael; García-Garizábal, Iker; Merchán, Daniel; Causapé, Jesús

    2015-02-01

    Climate change is affecting agriculture doubly: evapotranspiration is increasing due to increments in temperature while the availability of water resources is decreasing. Furthermore, irrigated areas are expanding worldwide. In this study, the dynamics of climate change impacts on the water cycle of a newly irrigated watershed are studied through the calculation of soil water balances. The study area was a 752-ha watershed located on the left side of the Ebro river valley, in Northeast Spain. The soil water balance procedures were carried out throughout 1827 consecutive days (5 years) of hydrological and agronomical monitoring in the study area. Daily data from two agroclimatic stations were used as well. Evaluation of the impact of climate change on the water cycle considered the creation of two future climate scenarios for comparison: 2070 decade with climate change and 2070 decade without climate change. The main indicators studied were precipitation, irrigation, reference evapotranspiration, actual evapotranspiration, drainage from the watershed, and irrigation losses. The aridity index was also applied. The results represent a baseline scenario in which adaptation measures may be included and tested to reduce the impacts of climate change in the studied area and other similar areas.

  19. The Indian Monsoon

    Indian Academy of Sciences (India)

    The word 'monsoon' is derived from the Arabic word 'mausam' for season and the distinguishing attribute of ... lance, the word monsoon is used for the rainfall in the rainy season. In this article, I discuss the ..... [1] C S Ramage, Monsoon meteorology, International Geophysics Series,. Academic Press, San Diego, California ...

  20. The climate and flood risk potential of northern areas of Pakistan

    International Nuclear Information System (INIS)

    Awan, S.A.

    2002-01-01

    The extreme floods in northern parts of Pakistan are caused by glacier lake outbursts and Dam-Breaks following landslides, which block river valleys. Geographically glacier dams in mountain rivers and valleys have occurred from the east-western and west-western Karakuram ranges and in the lesser Karakuram range floods which arise from Karakuram precipitation and temperature of various region pose greater problem, as these floods are neither homogeneous nor stationary. These floods arise from various generating mechanisms i. e. generated by melting of snow and glacier and those generated from the monsoon rainfall and dam-breaks following landslide into the river and out burst of glacier lake. The estimation of present and future risk of flooding at sites in northern Pakistan requires an understanding, of the climate, which provides, the generating mechanism of floods. Climates are extremely variable and depend op broad global circulation patterns and local topographic influences. The variables of the climate are studied using available data, with emphasis on temperature and precipitation Spatial Co-relation in northern area stations have been conducted to find Co-relation Co-efficient, using regression analysis. This is spread over intra seasonal and inter station comparison. The time series analysis of the climatic variables has been conducted to examine geographically and statistically the trend in their behaviour. This may be reflected in the hydrological regime of glaciers and rivers and it can cause non linear flood series through changes in any one of the flood generating mechanism. The climate feed-back mechanism has been discussed, which are practically important because they assist seasonal prediction of climate and flow in the Indus. Additionally if climate warming is causing an upward Trend in winter and spring temperature and reduction in snowfall, the effect might be felt more widely over the region. The non-linear changes with elevation and differences

  1. Asian Eocene monsoons as revealed by leaf architectural signatures

    Science.gov (United States)

    Spicer, Robert A.; Yang, Jian; Herman, Alexei B.; Kodrul, Tatiana; Maslova, Natalia; Spicer, Teresa E. V.; Aleksandrova, Galina; Jin, Jianhua

    2016-09-01

    The onset and development of the Asian monsoon systems is a topic that has attracted considerable research effort but proxy data limitations, coupled with a diversity of definitions and metrics characterizing monsoon phenomena, have generated much debate. Failure of geological proxies to yield metrics capable of distinguishing between rainfall seasonality induced by migrations of the Inter-tropical Convergence Zone (ITCZ) from that attributable to topographically modified seasonal pressure reversals has frustrated attempts to understand mechanisms underpinning monsoon development and dynamics. Here we circumvent the use of such single climate parameter metrics in favor of detecting directly the distinctive attributes of different monsoon regimes encoded in leaf fossils. Leaf form adapts to the prevailing climate, particularly under the extreme seasonal stresses imposed by monsoons, so it is likely that fossil leaves carry a unique signature of past monsoon regimes. Leaf form trait spectra obtained from fossils from Eocene basins in southern China were compared with those seen in modern leaves growing under known climate regimes. The fossil leaf trait spectra, including those derived from previously published fossil floras from northwestern India, were most similar to those found in vegetation exposed to the modern Indonesia-Australia Monsoon (I-AM), which is largely a product of seasonal migrations of the ITCZ. The presence of this distinctive leaf physiognomic signature suggests that although a monsoon climate existed in Eocene time across southern Asia the characteristics of the modern topographically-enhanced South Asia Monsoon had yet to develop. By the Eocene leaves in South Asia had become well adapted to an I-AM type regime across many taxa and points to the existence of a pervasive monsoon climate prior to the Eocene. No fossil trait spectra typical of exposure to the modern East Asia monsoon were seen, suggesting the effects of this system in southern

  2. Gridded daily Indian monsoon rainfall for 14 seasons: Merged ...

    Indian Academy of Sciences (India)

    Indian monsoon is an important component of earth's climate system. Daily rainfall data for longer period is vital to study components and processes related to Indian monsoon. Daily observed gridded rainfall data covering both land and adjoining oceanic regions are required for numerical model vali- dation and model ...

  3. Biotic and Climatic Velocity Identify Contrasting Areas of Vulnerability to Climate Change

    Science.gov (United States)

    Carroll, Carlos; Lawler, Joshua J.; Roberts, David R.; Hamann, Andreas

    2015-01-01

    Metrics that synthesize the complex effects of climate change are essential tools for mapping future threats to biodiversity and predicting which species are likely to adapt in place to new climatic conditions, disperse and establish in areas with newly suitable climate, or face the prospect of extirpation. The most commonly used of such metrics is the velocity of climate change, which estimates the speed at which species must migrate over the earth’s surface to maintain constant climatic conditions. However, “analog-based” velocities, which represent the actual distance to where analogous climates will be found in the future, may provide contrasting results to the more common form of velocity based on local climate gradients. Additionally, whereas climatic velocity reflects the exposure of organisms to climate change, resultant biotic effects are dependent on the sensitivity of individual species as reflected in part by their climatic niche width. This has motivated development of biotic velocity, a metric which uses data on projected species range shifts to estimate the velocity at which species must move to track their climatic niche. We calculated climatic and biotic velocity for the Western Hemisphere for 1961–2100, and applied the results to example ecological and conservation planning questions, to demonstrate the potential of such analog-based metrics to provide information on broad-scale patterns of exposure and sensitivity. Geographic patterns of biotic velocity for 2954 species of birds, mammals, and amphibians differed from climatic velocity in north temperate and boreal regions. However, both biotic and climatic velocities were greatest at low latitudes, implying that threats to equatorial species arise from both the future magnitude of climatic velocities and the narrow climatic tolerances of species in these regions, which currently experience low seasonal and interannual climatic variability. Biotic and climatic velocity, by approximating

  4. Mapping urban climate zones and quantifying climate behaviors--an application on Toulouse urban area (France).

    Science.gov (United States)

    Houet, Thomas; Pigeon, Grégoire

    2011-01-01

    Facing the concern of the population to its environment and to climatic change, city planners are now considering the urban climate in their choices of planning. The use of climatic maps, such Urban Climate Zone‑UCZ, is adapted for this kind of application. The objective of this paper is to demonstrate that the UCZ classification, integrated in the World Meteorological Organization guidelines, first can be automatically determined for sample areas and second is meaningful according to climatic variables. The analysis presented is applied on Toulouse urban area (France). Results show first that UCZ differentiate according to air and surface temperature. It has been possible to determine the membership of sample areas to an UCZ using landscape descriptors automatically computed with GIS and remote sensed data. It also emphasizes that climate behavior and magnitude of UCZ may vary from winter to summer. Finally we discuss the influence of climate data and scale of observation on UCZ mapping and climate characterization. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. The effect of El-Niño on South Asian Monsoon and agricultural production

    Science.gov (United States)

    Mukherjee, A.

    2015-12-01

    Mukherjee A, Wang S.Y.Abstract:The South Asian Monsoon has a prominent and significant impact on South Asian countries like India, Bangladesh, Nepal, Pakistan, Sri Lanka and it is one of the most studied phenomena in the world. The monsoon is historically known to be influenced by El Niño-Southern Oscillation (ENSO). The inter-annual and inter-decadal variability of seasonal precipitation over India strongly depends upon the ENSO phasing. The average southwest monsoon rainfall received during the years with El Niño was found to be less compared to normal years and the average rainfall during the northeast monsoon is higher in coastal Andhra Pradesh. ENSO is anti-correlated with Indian summer monsoon (ISM). The last prominent effect of ENSO on India's monsoon occurred in 2009 with 23% reduction in annual rainfall, reducing summer sown crops such as rice, sugar cane etc. and pushing up food prices. Climatic resources endowment plays a major role in planning agricultural production in tropical and sub-tropical environment especially under rain-fed agriculture, and so contingent crop planning drawn on this relationship would help to mitigate the effects of ENSO episodes in the region. The unexplored area in this domain of research is the changes in the frequency and intensity of ENSO due to global warming and its impact on ENSO prediction and agricultural management practices. We analyze the last 30 years datasets of Pacific SST, and precipitation and air temperature over Southeast Asia to examine the evolution of ENSO teleconnections with ISM, as well as making estimates of drought indices such as Palmer Drought Severity Index. This research can lead toward better crop management strategies in the South Asian monsoon region.

  6. Microplankton biomass and diversity in the Vietnamese upwelling area during SW monsoon under normal conditions and after an ENSO event

    DEFF Research Database (Denmark)

    Loick-Wilde, Natalie; Bombar, Deniz; Doan, Hai Nhu

    2017-01-01

    to show how climatological-driven changes can have a significant influence on the distribution of microplankton communities and their biomass via its impact on nutrient concentrations in the water column. The first summer in July 2003 followed a weak El-Nino Southern Oscillation (ENSO) event...... (10–20 µm) prevailed ubiquitously during reduced upwelling. During normal upwelling, the diatom Rhizosolenia sp. dominated the cell-carbon biomass in the silicate poor upwelling waters. Trichodesmium erythraeum dominated in the Mekong-influenced and nutrient depleted offshore waters, where it co......Investigating microplankton biomass and diversity under different climatological conditions is key to the understanding of cascading effects of climate change on nutrient cycles and biological productivity. Here we have used data collected during two contrasting summers along the coast of Viet Nam...

  7. Climate change and protected area policy and planning in Canada

    Energy Technology Data Exchange (ETDEWEB)

    Scott, D. [Canada Research Chairs, Ottawa, ON (Canada); Waterloo Univ., ON (Canada). Dept. of Geography; Lemieux, C. [Waterloo Univ., ON (Canada). Dept. of Geography

    2005-10-01

    Challenges concerning climate change for agencies involved the management of Canada's protected areas were reviewed. Most protected areas have been designed to represent specific natural features, species and ecological communities, and are the most common and most important strategy for biodiversity conservation. It remains undecided whether adaptation should be a matter of responding to climate change as it manifests, or whether initiatives should be taken in advance to anticipate the potential effects of climate change. There are growing concerns that emergency adaptation will be less effective and more costly than anticipatory or precautionary adaptation over the long-term. Species extinction could result. It was noted that the northward shift of species from the United States will meet Parks Canada's existing definition of alien species in need of management interventions. The conservation objectives of individual protected areas would also be affected by projected biome and species changes, particularly as each of Canada's national parks is responsible for protecting ecosystems representative of the natural region within which it is located. All 6 vegetation change scenarios examined in a recent study projected the eventual loss of boreal forest in the Prince Albert National Park, suggesting that the park's current mandate to protect the ecological integrity of the area would no longer be viable. An overview of the policy and planning implications of climate change for protected areas in Canada was presented using examples from national and provincial park systems. A portfolio of climate change adaptation options in conservation literature was reviewed. Recommended strategies included system planning and policy development; active, adaptive ecosystem management; research and monitoring; and capacity building and awareness. It was concluded that governments will need to make major new investments in protected area establishment, personnel

  8. Joint influence of the Indo-Pacific Warm Pool and Northern Arabian Sea Temperatures on the Indian Summer Monsoon in a Global Climate Model Simulation

    Science.gov (United States)

    Befort, Daniel J.; Leckebusch, Gregor C.; Cubasch, Ulrich

    2016-04-01

    Proxy-based studies confirmed that the Indian Summer Monsoon (ISM) shows large variations during the Holocene. These changes might be explained by changes in orbital conditions and solar insolation but are also thought to be associated to changes in oceanic conditions, e.g. over the Indo-Pacific-Warm-Pool region. However, due to the nature of these (proxy-based) analyses no conclusion about atmospheric circulation changes during dry and wet epochs are possible. Here, a fully-coupled global climate simulation (AOGCM) covering the past 6000 years is analysed regarding ISM variability. Several dry and wet epochs are found, the most striking around 2ka BP (dry) and 1.7ka BP (wet). As only orbital parameters change during integration, we expect these "shorter-term" changes to be associated with changes in oceanic conditions. During 1.7ka BP the sea surface temperatures (SST) over the Northern Arabian Sea (NARAB) are significantly warmer compared to 2ka BP, whereas cooler conditions are found over the western Pacific Ocean. Additionally, significant differences are found over large parts of the North Atlantic. To explain in how far these different ocean basins are responsible for anomalous conditions during 1.7ka BP, several sensitivity experiments with changed SST/SIC conditions are carried out. It is found that neither the SST's in the Pacific nor in the Indian Ocean are able to reproduce the anomalous rainfall and atmospheric circulation patterns during 1.7ka on its own. Instead, anomalous dry conditions during 2ka BP and wet conditions during 1.7ka BP are associated with a shift of the Indo-Pacific-Warm-Pool (IPWP) and simultaneous anomalous sea-surface temperatures over the NARAB region. Eventually, it is tested in how far this hypothesis holds true for other dry and wet events in the AOGCM data during the whole 6000 years. In general, a shift of the IPWP without anomalous SST conditions over the NARAB region (and vice versa) is not sufficient to cause long

  9. Unusual rainfall shift during monsoon period of 2010 in Pakistan ...

    African Journals Online (AJOL)

    Arslan

    2013-09-04

    Sep 4, 2013 ... Key words: Indus River, monsoon, flooding in 2010, rainfall pattern, Climate ... data was plotted in excel sheet with upper and lower limits defined .... Houze Jr, Rasmussen R, Medina K, Brodzik S, Romatschke SU (2011).

  10. Dinoflagellates in a mesotrophic, tropical environment influenced by monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    DeCosta, P.M.; Anil, A.C.; Patil, J.S.; Hegde, S.; DeSilva, M.S.; Chourasia, M.

    The changes in dinoflagellate community structure in both e the water column and sediment in a mesotrophic, tropical port environment were investigated in this study. Since the South West Monsoon (SWM) is the main source of climatic variation...

  11. The Indian Monsoon

    Indian Academy of Sciences (India)

    user

    and led to the expectation that the impact of the monsoon on the ... a lead time of 10 days to a month for rainfall, temperature, etc., ... trying to predict, such as clouds or a monsoon depression (in ... occur because (i) the models are not perfect (involving many ... ally at many centres in the world, long-range predictions are.

  12. The Indian Monsoon

    Indian Academy of Sciences (India)

    Pacific Oceans, on subseasonal scales of a few days and on an interannual scale. ... over the Indian monsoon zone2 (Figure 3) during the summer monsoon .... each 500 km ×500 km grid over the equatorial Indian Ocean, Bay of Bengal and ...

  13. Influence of savanna fire on Australian monsoon season precipitation and circulation as simulated using a distributed computing environment

    Science.gov (United States)

    Lynch, Amanda H.; Abramson, David; Görgen, Klaus; Beringer, Jason; Uotila, Petteri

    2007-10-01

    Fires in the Australian savanna have been hypothesized to affect monsoon evolution, but the hypothesis is controversial and the effects have not been quantified. A distributed computing approach allows the development of a challenging experimental design that permits simultaneous variation of all fire attributes. The climate model simulations are distributed around multiple independent computer clusters in six countries, an approach that has potential for a range of other large simulation applications in the earth sciences. The experiment clarifies that savanna burning can shape the monsoon through two mechanisms. Boundary-layer circulation and large-scale convergence is intensified monotonically through increasing fire intensity and area burned. However, thresholds of fire timing and area are evident in the consequent influence on monsoon rainfall. In the optimal band of late, high intensity fires with a somewhat limited extent, it is possible for the wet season to be significantly enhanced.

  14. The roles of natural areas in a changing climate

    International Nuclear Information System (INIS)

    Pollard, D.F.W.

    1991-01-01

    Natural areas are protected sites which are integral parts of a systematic network representing the diversity of natural environments. They are relatively undisturbed by man, selected according to ecological criteria, have assured permanency, are set aside mainly for scientific and educational purposes, and harbor genetic materials of value to society. In the Pacific Northwest, natural areas have been established by the United States Forest Service and the British Columbia Ministry of the Environment and include national parks, wilderness areas, wildlife refuges, and wild rivers. A change in climate will undoubtedly create a mismatch between climatic regions and vegetation and wildlife occupying them. The distribution of plant and animal species will change. Species and communities that will be most affected by climatic change include those at the contracting periphery of the species range, genetically impoverished or highly sensitive species, annual plants, and Arctic and coastal communities. Most species will disperse from existing locations, with variable and unpredictable results. It is conceivable that natural areas will evolve from their current role as refuges to a new role as centers of diversity from which genes migrate into a changing world. Natural areas also serve as a base for biomonitoring of long-term environmental changes and for assessing effects of interventions such as acid precipitation. 32 refs

  15. Changes in observed climate extremes in global urban areas

    International Nuclear Information System (INIS)

    Mishra, Vimal; Ganguly, Auroop R; Nijssen, Bart; Lettenmaier, Dennis P

    2015-01-01

    Climate extremes have profound implications for urban infrastructure and human society, but studies of observed changes in climate extremes over the global urban areas are few, even though more than half of the global population now resides in urban areas. Here, using observed station data for 217 urban areas across the globe, we show that these urban areas have experienced significant increases (p-value <0.05) in the number of heat waves during the period 1973–2012, while the frequency of cold waves has declined. Almost half of the urban areas experienced significant increases in the number of extreme hot days, while almost 2/3 showed significant increases in the frequency of extreme hot nights. Extreme windy days declined substantially during the last four decades with statistically significant declines in about 60% in the urban areas. Significant increases (p-value <0.05) in the frequency of daily precipitation extremes and in annual maximum precipitation occurred at smaller fractions (17 and 10% respectively) of the total urban areas, with about half as many urban areas showing statistically significant downtrends as uptrends. Changes in temperature and wind extremes, estimated as the result of a 40 year linear trend, differed for urban and non-urban pairs, while changes in indices of extreme precipitation showed no clear differentiation for urban and selected non-urban stations. (letter)

  16. Assessing Climate Change Impacts on Wildfire Exposure in Mediterranean Areas.

    Science.gov (United States)

    Lozano, Olga M; Salis, Michele; Ager, Alan A; Arca, Bachisio; Alcasena, Fermin J; Monteiro, Antonio T; Finney, Mark A; Del Giudice, Liliana; Scoccimarro, Enrico; Spano, Donatella

    2017-10-01

    We used simulation modeling to assess potential climate change impacts on wildfire exposure in Italy and Corsica (France). Weather data were obtained from a regional climate model for the period 1981-2070 using the IPCC A1B emissions scenario. Wildfire simulations were performed with the minimum travel time fire spread algorithm using predicted fuel moisture, wind speed, and wind direction to simulate expected changes in weather for three climatic periods (1981-2010, 2011-2040, and 2041-2070). Overall, the wildfire simulations showed very slight changes in flame length, while other outputs such as burn probability and fire size increased significantly in the second future period (2041-2070), especially in the southern portion of the study area. The projected changes fuel moisture could result in a lengthening of the fire season for the entire study area. This work represents the first application in Europe of a methodology based on high resolution (250 m) landscape wildfire modeling to assess potential impacts of climate changes on wildfire exposure at a national scale. The findings can provide information and support in wildfire management planning and fire risk mitigation activities. © 2016 Society for Risk Analysis.

  17. Did Aboriginal vegetation burning affect the Australian summer monsoon?

    Science.gov (United States)

    Balcerak, Ernie

    2011-08-01

    For thousands of years, Aboriginal Australians burned forests, creating grasslands. Some studies have suggested that in addition to changing the landscape, these burning practices also affected the timing and intensity of the Australian summer monsoon. Different vegetation types can alter evaporation, roughness, and surface reflectivity, leading to changes in the weather and climate. On the basis of an ensemble of experiments with a global climate model, Notaro et al. conducted a comprehensive evaluation of the effects of decreased vegetation cover on the summer monsoon in northern Australia. They found that although decreased vegetation cover would have had only minor effects during the height of the monsoon season, during the premonsoon season, burning-induced vegetation loss would have caused significant decreases in precipitation and increases in temperature. Thus, by burning forests, Aboriginals altered the local climate, effectively extending the dry season and delaying the start of the monsoon season. (Geophysical Research Letters, doi:10.1029/2011GL047774, 2011)

  18. Understanding the Unusual 2017 Monsoon and Floods in South Asia

    Science.gov (United States)

    Akanda, A. S.; Palash, W.; Hasan, M. A.; Nusrat, F.

    2017-12-01

    Driven primarily by the South Asian Monsoon, the Ganges-Brahmaputra-Meghna (GBM) river basin system collectively drains intense precipitation for an area of more than 1.5 million square kilometers during the wet summer season. Bangladesh, being the lowest riparian country in the system, experiences recurrent floods and immense suffering to its population. The 2017 monsoon season was quite unusual in terms of the characteristics of the precipitation received in the basin. The monsoon was spread out over a much larger time span (April-October) compared to the average monsoon season (June-September). Although the monsoon does not typically start until June in Bangladesh, the 2017 season started much earlier in April with unusually heavy precipitation in the Meghna basin region and caused major damage to agriculture in northeastern Bangladesh. The rainfall continued in several record-breaking pulses, compared to the typical one or two large waves. One of the largest pulses occurred in early August with very high in intensity and volume, causing ECMWF to issue a major warning about widespread flooding in Bangladesh, Northern India, and Eastern Nepal. This record flood event impacted over 40 million people in the above regions, causing major damage to life and infrastructure. Although the Brahmaputra rose above the danger level several times this season, the Ganges was unusually low, thus sparing downstream areas from disastrous floods. However, heavy precipitation continued until October, causing urban flooding in Dhaka and Chittagong - and worsening sanitation and public health conditions in southern Bangladesh - currently undergoing a terrible humanitarian crisis involving Rohingya refugees from the Myanmar. Despite marked improvement in flood forecasting systems in recent years, the 2017 floods identified critical gaps in our understanding of the flooding phenomena and limitations of dissemination in these regions. In this study, we investigate 1) the unusual

  19. Glacial to Holocene swings of the Australian-Indonesian monsoon

    Science.gov (United States)

    Mohtadi, Mahyar; Oppo, Delia W.; Steinke, Stephan; Stuut, Jan-Berend W.; de Pol-Holz, Ricardo; Hebbeln, Dierk; Lückge, Andreas

    2011-08-01

    The Australian-Indonesian monsoon is an important component of the climate system in the tropical Indo-Pacific region. However, its past variability, relation with northern and southern high-latitude climate and connection to the other Asian monsoon systems are poorly understood. Here we present high-resolution records of monsoon-controlled austral winter upwelling during the past 22,000 years, based on planktic foraminiferal oxygen isotopes and faunal composition in a sedimentary archive collected offshore southern Java. We show that glacial-interglacial variations in the Australian-Indonesian winter monsoon were in phase with the Indian summer monsoon system, consistent with their modern linkage through cross-equatorial surface winds. Likewise, millennial-scale variability of upwelling shares similar sign and timing with upwelling variability in the Arabian Sea. On the basis of element composition and grain-size distribution as precipitation-sensitive proxies in the same archive, we infer that (austral) summer monsoon rainfall was highest during the Bølling-Allerød period and the past 2,500 years. Our results indicate drier conditions during Heinrich Stadial 1 due to a southward shift of summer rainfall and a relatively weak Hadley cell south of the Equator. We suggest that the Australian-Indonesian summer and winter monsoon variability were closely linked to summer insolation and abrupt climate changes in the northern hemisphere.

  20. Climate change, species-area curves and the extinction crisis.

    Science.gov (United States)

    Lewis, Owen T

    2006-01-29

    An article published in the journal Nature in January 2004-in which an international team of biologists predicted that climate change would, by 2050, doom 15-37% of the earth's species to extinction-attracted unprecedented, worldwide media attention. The predictions conflict with the conventional wisdom that habitat change and modification are the most important causes of current and future extinctions. The new extinction projections come from applying a well-known ecological pattern, the species-area relationship (SAR), to data on the current distributions and climatic requirements of 1103 species. Here, I examine the scientific basis to the claims made in the Nature article. I first highlight the potential and pitfalls of using the SAR to predict extinctions in general. I then consider the additional complications that arise when applying SAR methods specifically to climate change. I assess the extent to which these issues call into question predictions of extinctions from climate change relative to other human impacts, and highlight a danger that conservation resources will be directed away from attempts to slow and mitigate the continuing effects of habitat destruction and degradation, particularly in the tropics. I suggest that the most useful contributions of ecologists over the coming decades will be in partitioning likely extinctions among interacting causes and identifying the practical means to slow the rate of species loss.

  1. Climate projections in the Hornsund area, Southern Spitsbergen

    Directory of Open Access Journals (Sweden)

    Osuch Marzena

    2016-09-01

    Full Text Available The aim of this study was to provide an estimation of climate variability in the Hornsund area in Southern Spitsbergen in the period 1976-2100. The climatic variables were obtained from the Polar-CORDEX initiative in the form of time series of daily air temperature and precipitation derived from four global circulation models (GCMs following representative concentration pathways (RCP RCP 4.5 and RCP 8.5 emission scenarios. In the first stage of the analysis, simulations for the reference period from 1979 to 2005 were compared with observations at the Polish Polar Station Hornsund from the same period of time. In the second step, climatic projections were derived and monthly and annual means/sums were analysed as climatic indices. Following the standard methods of trend analysis, the changes of these indices over three time periods - the reference period 1976-2005, the near-future period 2021-2050, and far-future period 2071-2100 - were examined. The projections of air temperature were consistent. All analysed climate models simulated an increase of air temperature with time. Analyses of changes at a monthly scale indicated that the largest increases were estimated for winter months (more than 11°C for the far future using the RCP 8.5 scenario. The analyses of monthly and annual sums of precipitation also indicated increasing tendencies for changes with time, with the differences between mean monthly sums of precipitation for the near future and the reference period similar for each months. In the case of changes between far future and reference periods, the highest increases were projected for the winter months.

  2. Climate change considerations for the Port Hope area initiative

    International Nuclear Information System (INIS)

    Kirklady, J.; Morassutti, M.; Tamm, J.; Coutts, P.; Chambers, D.

    2006-01-01

    The Port Hope Area Initiative (PHAI) is a community-based program intended to develop a safe and long-term (approximately 500 years) solution for the management of historic low-level radioactive waste (LLRW) that has been present in the Port Hope area for many years. The PHAI undertakings involve the construction and management of two Long-Term Low-Level Radioactive Waste Management Facilities (referred to as the LTWMFs) in Port Hope and in Port Granby. These undertakings are currently undergoing detailed examination through the Environmental Screening process under the Canadian Environmental Assessment Act. The purpose of the study described in this paper was to provide information necessary to satisfy the requirements of the Scope of Environmental Assessment for the Port Hope and Port Granby Projects. In particular, the purpose of the study was to satisfy the requirements to evaluate greenhouse gas (GHG) emissions from the proposed PHAI initiatives and to evaluate the potential effect of climate change parameters on the two Projects. The Port Hope and Port Granby Projects will contribute to Ontario's GHG emission inventory due to vehicle exhaust from excavation equipment and haul trucks during the construction phase of the LTWMFs. The construction phase of the Projects is of relatively short duration, and the contribution of GHGs from each Project was determined to be insignificant compared to Ontario's GHG emissions from the Construction and Transportations sectors. The proposed project elements associated with the Port Hope and Port Granby Projects were each evaluated with respect to potential sensitivities to future change in climate parameters. Considering the potential changes to climate, a screening analysis of each element of the LTWMFs was undertaken. Because it is considered likely that the current design level storms will be exceeded within the next 500 years, it was determined that the storm water management system was potentially sensitive to changes

  3. Climate services for an urban area (Baia Mare City, Romania) with a focus on climate extremes

    Science.gov (United States)

    Sima, Mihaela; Micu, Dana; Dragota, Carmen-Sofia; Mihalache, Sorin

    2013-04-01

    The Baia Mare Urban System is located in the north-western part of Romania, with around 200,000 inhabitants and represents one of the most important former mining areas in the country, whose socioeconomic profile and environmental conditions have greatly changed over the last 20 years during the transition and post-transition period. Currently the mining is closed in the area, but the historical legacy of this activity has implications in terms of economic growth, social and cultural developments and environmental quality. Baia Mare city lies in an extended depression, particularly sheltered by the mountain and hilly regions located in the north and respectively, in the south-south-eastern part of it, which explains the high frequency of calm conditions and low airstream channeling occurrences. This urban system has a typically moderate temperate-continental climate, subject to frequent westerly airflows (moist), which moderate the thermal regime (without depicting severe extremes, both positive and negative) and enhance the precipitation one (entailing a greater frequency of wet extremes). During the reference period (1971-2000), the climate change signal in the area is rather weak and not statistically significant. However, since the mid 1980s, the warming signal became more evident from the observational data (Baia Mare station), showing a higher frequency of dry spells and positive extremes. The modelling experiments covering the 2021-2050 time horizon using regional (RM5.1/HadRM3Q0/RCA3) and global (ARPEGE/HadCM3Q0/BCM/ECHAM5) circulation models carried out within the ECLISE FP7 project suggest an ongoing temperature rise, associated to an intensification of temperature and precipitation extremes. In this context, the aim of this study was to evaluate how the local authorities consider and include climate change in their activity, as well as in the development plans (e.g. territorial, economic and social development plans). Individual interviews have been

  4. Recent trends in pre-monsoon daily temperature extremes over India

    Indian Academy of Sciences (India)

    e-mail: kotha@tropmet.res.in. Extreme climate and weather events are increasingly being recognized as key aspects of climate change. Pre-monsoon season ... change in day-to-day magnitude of fluctuations of pre-monsoon maximum and minimum tempera- tures. ... by high exceedence counts during drought periods.

  5. Energetics and monsoon bifurcations

    Science.gov (United States)

    Seshadri, Ashwin K.

    2017-01-01

    Monsoons involve increases in dry static energy (DSE), with primary contributions from increased shortwave radiation and condensation of water vapor, compensated by DSE export via horizontal fluxes in monsoonal circulations. We introduce a simple box-model characterizing evolution of the DSE budget to study nonlinear dynamics of steady-state monsoons. Horizontal fluxes of DSE are stabilizing during monsoons, exporting DSE and hence weakening the monsoonal circulation. By contrast latent heat addition (LHA) due to condensation of water vapor destabilizes, by increasing the DSE budget. These two factors, horizontal DSE fluxes and LHA, are most strongly dependent on the contrast in tropospheric mean temperature between land and ocean. For the steady-state DSE in the box-model to be stable, the DSE flux should depend more strongly on the temperature contrast than LHA; stronger circulation then reduces DSE and thereby restores equilibrium. We present conditions for this to occur. The main focus of the paper is describing conditions for bifurcation behavior of simple models. Previous authors presented a minimal model of abrupt monsoon transitions and argued that such behavior can be related to a positive feedback called the `moisture advection feedback'. However, by accounting for the effect of vertical lapse rate of temperature on the DSE flux, we show that bifurcations are not a generic property of such models despite these fluxes being nonlinear in the temperature contrast. We explain the origin of this behavior and describe conditions for a bifurcation to occur. This is illustrated for the case of the July-mean monsoon over India. The default model with mean parameter estimates does not contain a bifurcation, but the model admits bifurcation as parameters are varied.

  6. Centennial- to decadal-scale monsoon precipitation variations in the upper Hanjiang River region, China over the past 6650 years

    Science.gov (United States)

    Tan, Liangcheng; Cai, Yanjun; Cheng, Hai; Edwards, Lawrence R.; Gao, Yongli; Xu, Hai; Zhang, Haiwei; An, Zhisheng

    2018-01-01

    The upper Hanjiang River region is the recharge area of the middle route of South-to-North Water Transfer Project. The region is under construction of the Hanjiang-Weihe River Water Transfer Project in China. Monsoon precipitation variations in this region are critical to water resource and security of China. In this study, high-resolution monsoon precipitation variations were reconstructed in the upper Hanjiang River region over the past 6650 years from δ18O and δ13C records of four stalagmites in Xianglong cave. The long term increasing trend of stalagmite δ18O record since the middle Holocene is consistent with other speleothem records from monsoonal China. This trend follows the gradually decreasing Northern Hemisphere summer insolation, which indicates that solar insolation may control the orbital-scale East Asian summer monsoon (EASM) variations. Despite the declined EASM intensity since the middle Holocene, local precipitation may not have decreased remarkably, as revealed by the δ13C records. A series of centennial- to decadal-scale cyclicity was observed, with quasi-millennium-, quasi-century-, 57-, 36- and 22-year cycles by removing the long-term trend of stalagmite δ18O record. Increased monsoon precipitation during periods of 4390-3800 a BP, 3590-2960 a BP, 2050-1670 a BP and 1110-790 a BP had caused four super-floods in the upper reach of Hanjiang River. Dramatically dry climate existed in this region during the 5.0 ka and 2.8 ka events, coinciding with notable droughts in other regions of monsoonal China. Remarkably intensified and southward Westerly jet, together with weakened summer monsoon, may delay the onset of rainy seasons, resulting in synchronous decreasing of monsoon precipitation in China during the two events. During the 4.2 ka event and the Little Ice Age, the upper Hanjiang River region was wet, which was similar to the climate conditions in central and southern China, but was the opposite of drought observed in northern China. We

  7. Quantitative Study of Green Area for Climate Sensitive Terraced Housing Area Design in Malaysia

    International Nuclear Information System (INIS)

    Yeo, O T S; Saito, K; Said, I

    2014-01-01

    Neighbourhood plays a significant role in peoples' daily lives. Nowadays, terraced housing is common in Malaysia, and green areas in the neighborhood are not used to their maximum. The aim of the research is to quantify the types of green area that are most efficient for cooling the environment for thermal comfort and mitigation of Urban Heat Island. Spatial and environmental inputs are manipulated for the simulation using Geographic Information System (GIS) integrated with computational microclimate simulation. The outcome of this research is a climate sensitive housing environment model framework on the green area to solve the problem of Urban Heat Island

  8. Predictor-Year Subspace Clustering Based Ensemble Prediction of Indian Summer Monsoon

    Directory of Open Access Journals (Sweden)

    Moumita Saha

    2016-01-01

    Full Text Available Forecasting the Indian summer monsoon is a challenging task due to its complex and nonlinear behavior. A large number of global climatic variables with varying interaction patterns over years influence monsoon. Various statistical and neural prediction models have been proposed for forecasting monsoon, but many of them fail to capture variability over years. The skill of predictor variables of monsoon also evolves over time. In this article, we propose a joint-clustering of monsoon years and predictors for understanding and predicting the monsoon. This is achieved by subspace clustering algorithm. It groups the years based on prevailing global climatic condition using statistical clustering technique and subsequently for each such group it identifies significant climatic predictor variables which assist in better prediction. Prediction model is designed to frame individual cluster using random forest of regression tree. Prediction of aggregate and regional monsoon is attempted. Mean absolute error of 5.2% is obtained for forecasting aggregate Indian summer monsoon. Errors in predicting the regional monsoons are also comparable in comparison to the high variation of regional precipitation. Proposed joint-clustering based ensemble model is observed to be superior to existing monsoon prediction models and it also surpasses general nonclustering based prediction models.

  9. Monsoon onset over Kerala and pre monsoon rainfall peak

    Digital Repository Service at National Institute of Oceanography (India)

    RameshKumar, M.R.; Shenoi, S.S.C.; Shankar, D.

    and the monsoon onset date over Kerala was found to be 0.72, which was statistically significant. Thus, as is felt that the pre monsoon rainfall estimate from the satellite data can be used for predicting the monsoon onset over Kerala coast. The results...

  10. Variation in the Asian monsoon intensity and dry-wet conditions since the Little Ice Age in central China revealed by an aragonite stalagmite

    Science.gov (United States)

    Yin, J.-J.; Yuan, D.-X.; Li, H.-C.; Cheng, H.; Li, T.-Y.; Edwards, R. L.; Lin, Y.-S.; Qin, J.-M.; Tang, W.; Zhao, Z.-Y.; Mii, H.-S.

    2014-10-01

    This paper focuses on the climate variability in central China since AD 1300, involving: (1) a well-dated, 1.5-year resolution stalagmite δ18O record from Lianhua Cave, central China (2) links of the δ18O record with regional dry-wet conditions, monsoon intensity, and temperature over eastern China (3) correlations among drought events in the Lianhua record, solar irradiation, and ENSO (El Niño-Southern Oscillation) variation. We present a highly precise, 230Th / U-dated, 1.5-year resolution δ18O record of an aragonite stalagmite (LHD1) collected from Lianhua Cave in the Wuling Mountain area of central China. The comparison of the δ18O record with the local instrumental record and historical documents indicates that (1) the stalagmite δ18O record reveals variations in the summer monsoon intensity and dry-wet conditions in the Wuling Mountain area. (2) A stronger East Asian summer monsoon (EASM) enhances the tropical monsoon trough controlled by ITCZ (Intertropical Convergence Zone), which produces higher spring quarter rainfall and isotopically light monsoonal moisture in the central China. (3) The summer quarter/spring quarter rainfall ratio in central China can be a potential indicator of the EASM strength: a lower ratio corresponds to stronger EASM and higher spring rainfall. The ratio changed from 1 after 1950, reflecting that the summer quarter rainfall of the study area became dominant under stronger influence of the Northwestern Pacific High. Eastern China temperatures varied with the solar activity, showing higher temperatures under stronger solar irradiation, which produced stronger summer monsoons. During Maunder, Dalton and 1900 sunspot minima, more severe drought events occurred, indicating a weakening of the summer monsoon when solar activity decreased on decadal timescales. On an interannual timescale, dry conditions in the study area prevailed under El Niño conditions, which is also supported by the spectrum analysis. Hence, our record

  11. On the relationship between Indian monsoon withdrawal and Iran's fall precipitation onset

    Science.gov (United States)

    Babaeian, Iman; Rezazadeh, Parviz

    2017-09-01

    Indian monsoon is the most prominent of the world's monsoon systems which primarily affects synoptic patterns of India and adjacent countries such as Iran in interaction with large-scale weather systems. In this article, the relationship between the withdrawal date of the Indian monsoon and the onset of fall precipitation in Iran has been studied. Data included annual time series of withdrawal dates of the Indian monsoon prepared by the Indian Institute for Tropical Meteorology, and time series of the first date of 25 mm accumulated precipitation over Iran's synoptic weather stations in a 10-day period which is the basis for the cultivation date. Both time series were considered in Julian calendar with the starting date on August 1. The studied period is 1960-2014 which covers 55 years of data from 36 meteorological stations in Iran. By classifying the withdrawal dates of the Indian monsoon in three stages of late, normal, and early withdrawals, its relation with the onset of fall precipitation in western, southwestern, southern, eastern, central, and northern regions of Iran was studied. Results demonstrated that in four out of the six mentioned regions, the late withdrawal of the Indian monsoon postpones the onset of fall precipitation over Iran. No significant relation was found between the onset of fall precipitation in central region of Iran and the monsoon's withdrawal date. In the western, southwestern, southern, and eastern regions of Iran, the late monsoon delays the onset of fall's precipitation; while in the south Caspian Sea coastal area, it causes the early onset of autumnal precipitation. The lag in onset of fall precipitation in Iran which is coordinated with the late withdrawal of monsoon is accompanied with prolonged subtropical high settling over Iran's plateau that prevents the southward movement of polar jet frontal systems. Such conditions enhance northerly wind currents over the Caspian Sea which, in turn, increase the precipitation in Caspian

  12. Climate influences the leaf area/sapwood area ratio in Scots pine.

    Science.gov (United States)

    Mencuccini, M; Grace, J

    1995-01-01

    We tested the hypothesis that the leaf area/sapwood area ratio in Scots pine (Pinus sylvestris L.) is influenced by site differences in water vapor pressure deficit of the air (D). Two stands of the same provenance were selected, one in western Scotland and one in eastern England, so that effects resulting from age, genetic variability, density and fertility were minimized. Compared with the Scots pine trees at the cooler and wetter site in Scotland, the trees at the warmer and drier site in England produced less leaf area per unit of conducting sapwood area both at a stem height of 1.3 m and at the base of the live crown, whereas stem permeability was similar at both sites. Also, trees at the drier site had less leaf area per unit branch cross-sectional area at the branch base than trees at the wetter site. For each site, the average values for leaf area, sapwood area and permeability were used, together with values of transpiration rates at different D, to calculate average stem water potential gradients. Changes in the leaf area/sapwood area ratio acted to maintain a similar water potential gradient in the stems of trees at both sites despite climatic differences between the sites.

  13. Climatic and non-climatic drivers of spatiotemporal maize-area dynamics across the northern limit for maize production

    DEFF Research Database (Denmark)

    Odgaard, Mette Vestergaard; Bøcher, Peder Klith; Dalgaard, Tommy

    2011-01-01

    It is expected that the ongoing anthropogenic climate change will drive changes in agricultural production and its geographic distribution. Here, we assess the extent to which climate change is already driving spatiotemporal dynamics in maize production in Denmark. We use advanced spatial...... regression modeling with multi-model averaging to assess the extent to which the recent spatiotemporal dynamics of the maize area in Denmark are driven by climate (temperature as represented by maize heating units [MHU] and growing-season precipitation), climate change and non-climatic factors (cattle...... cultivation and cattle farming, probably reflecting a change to a more favorable climate for maize cultivation: in the beginning of the study period, northern areas were mostly too cold for maize cultivation, irrespective of cattle density, but this limitation has been diminishing as climate has warmed...

  14. Effects of large-scale deforestation on precipitation in the monsoon regions: remote versus local effects.

    Science.gov (United States)

    Devaraju, N; Bala, Govindasamy; Modak, Angshuman

    2015-03-17

    In this paper, using idealized climate model simulations, we investigate the biogeophysical effects of large-scale deforestation on monsoon regions. We find that the remote forcing from large-scale deforestation in the northern middle and high latitudes shifts the Intertropical Convergence Zone southward. This results in a significant decrease in precipitation in the Northern Hemisphere monsoon regions (East Asia, North America, North Africa, and South Asia) and moderate precipitation increases in the Southern Hemisphere monsoon regions (South Africa, South America, and Australia). The magnitude of the monsoonal precipitation changes depends on the location of deforestation, with remote effects showing a larger influence than local effects. The South Asian Monsoon region is affected the most, with 18% decline in precipitation over India. Our results indicate that any comprehensive assessment of afforestation/reforestation as climate change mitigation strategies should carefully evaluate the remote effects on monsoonal precipitation alongside the large local impacts on temperatures.

  15. Tropical and Monsoonal Studies.

    Science.gov (United States)

    1988-01-01

    Duiing the cold surge event the balance of the 200 mb zonal momentum budget is between the zonal advecton of momentum and the coriolis, aceration ...over the South China Sea in the Malaysia ACKNOWLEDGEMENTS region during the winter monsoon, December 1973. Pure AppL Geophys., 115, 1303-1334. We wish

  16. The Indian Monsoon

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 13; Issue 3. The Indian Monsoon - Links to Cloud systems over the Tropical Oceans. Sulochana Gadgil. Series Article Volume 13 Issue 3 March 2008 pp 218-235. Fulltext. Click here to view fulltext PDF. Permanent link:

  17. Foretelling the Monsoon

    Indian Academy of Sciences (India)

    Relation between the continental TCZ and the TCZ over Equatorial Indian Ocean · Understanding year-to year (interannual) variation of the monsoon · Slide 40 · IMPACT OF EL NINO/LA NINA · Slide 42 · Variation of ISMR anomalies ( i.e. difference from the average value) normalized by std. deviation from 1979-2004.

  18. San Francisco Bay Area Rapid Transit District (BART) climate change adaptation assessment pilot.

    Science.gov (United States)

    2013-12-01

    The objective of this pilot study was to evaluate the impacts of climate change on the San Francisco Bay Area Rapid Transit District : (BART) infrastructure and to develop and implement adaptation strategies against those impacts. Climate change haza...

  19. The Summer Monsoon of 1987.

    Science.gov (United States)

    Krishnamurti, T. N.; Bedi, H. S.; Subramaniam, M.

    1989-04-01

    In this paper we have examined the evolution of a number of parameters we believe were important for our understanding of the drought over India during the summer of 1987. The list of parameters includes monthly means or anomalies of the following fields: sea surface temperatures, divergent circulations, outgoing longwave radiation, streamfunction of the lower and upper troposphere, and monthly precipitation (expressed as a percentage departure from a long-term mean). The El Niño related warm sea surface temperature anomaly and a weaker warm sea surface temperature anomaly over the equatorial Indian Ocean provide sustained convection, as reflected by the negative values of the outgoing longwave radiation. With the seasonal heating, a pronounced planetary-scale divergent circulation evolved with a center along the western Pacific Ocean. The monsoonal divergent circulation merged with that related to the El Niño, maintaining most of the heavy rainfall activity between the equatorial Pacific Ocean and east Asia. Persistent convective activity continued south of India during the entire monsoon season. Strong Hadley type overturnings with rising motions over these warm SST anomaly regions and descent roughly near 20° to 25°S was evident as early as April 1987. The subtropical high pressure areas near 20° to 25°S showed stronger than normal circulations. This was revealed by the presence of a counterclockwise streamfunction anomaly at 850 mb during April 1987. With the seasonal heating, this anomaly moved northwards and was located over the Arabian Sea and India. This countermonsoon circulation anomaly at the low levels was associated with a weaker than normal Somali jet and Arabian Sea circulation throughout this summer. The monsoon remained active along northeast India, Bangladesh, northern lndochina, and central China during the summer monsoon season. This was related to the eastward shift of the divergent circulation. An eastward shift of the upper tropospheric

  20. Climate change assessment for Mediterranean agricultural areas by statistical downscaling

    Directory of Open Access Journals (Sweden)

    L. Palatella

    2010-07-01

    Full Text Available In this paper we produce projections of seasonal precipitation for four Mediterranean areas: Apulia region (Italy, Ebro river basin (Spain, Po valley (Italy and Antalya province (Turkey. We performed the statistical downscaling using Canonical Correlation Analysis (CCA in two versions: in one case Principal Component Analysis (PCA filter is applied only to predictor and in the other to both predictor and predictand. After performing a validation test, CCA after PCA filter on both predictor and predictand has been chosen. Sea level pressure (SLP is used as predictor. Downscaling has been carried out for the scenarios A2 and B2 on the basis of three GCM's: the CCCma-GCM2, the Csiro-MK2 and HadCM3. Three consecutive 30-year periods have been considered. For Summer precipitation in Apulia region we also use the 500 hPa temperature (T500 as predictor, obtaining comparable results. Results show different climate change signals in the four areas and confirm the need of an analysis that is capable of resolving internal differences within the Mediterranean region. The most robust signal is the reduction of Summer precipitation in the Ebro river basin. Other significative results are the increase of precipitation over Apulia in Summer, the reduction over the Po-valley in Spring and Autumn and the increase over the Antalya province in Summer and Autumn.

  1. Prediction of monsoon rainfall with a nested grid mesoscale limited ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    At the India Meteorological Department (IMD), New Delhi, a 12-level limited area ... namurti et al (1995, 1998) noted that the Florida .... intensifies into monsoon depression giving rise to .... available to us on rainfall over the sea is the INSAT.

  2. Study of aerosol direct and indirect effects and auto-conversion processes over the West African monsoon region using a regional climate model

    Science.gov (United States)

    Salah, Zeinab; Shalaby, Ahmed; Steiner, Allison L.; Zakey, Ashraf S.; Gautam, Ritesh; Abdel Wahab, Mohamed M.

    2018-02-01

    This study assesses the direct and indirect effects of natural and anthropogenic aerosols (e.g., black carbon and sulfate) over West and Central Africa during the West African monsoon (WAM) period (June-July-August). We investigate the impacts of aerosols on the amount of cloudiness, the influences on the precipitation efficiency of clouds, and the associated radiative forcing (direct and indirect). Our study includes the implementation of three new formulations of auto-conversion parameterization [namely, the Beheng (BH), Tripoli and Cotton (TC) and Liu and Daum (R6) schemes] in RegCM4.4.1, besides the default model's auto-conversion scheme (Kessler). Among the new schemes, BH reduces the precipitation wet bias by more than 50% over West Africa and achieves a bias reduction of around 25% over Central Africa. Results from detailed sensitivity experiments suggest a significant path forward in terms of addressing the long-standing issue of the characteristic wet bias in RegCM. In terms of aerosol-induced radiative forcing, the impact of the various schemes is found to vary considerably (ranging from -5 to -25 W m-2).

  3. Transient coupling relationships of the Holocene Australian monsoon

    Science.gov (United States)

    McRobie, F. H.; Stemler, T.; Wyrwoll, K.-H.

    2015-08-01

    The northwest Australian summer monsoon owes a notable degree of its interannual variability to interactions with other regional monsoon systems. Therefore, changes in the nature of these relationships may contribute to variability in monsoon strength over longer time scales. Previous attempts to evaluate how proxy records from the Indonesian-Australian monsoon region correspond to other records from the Indian and East Asian monsoon regions, as well as to El Niño-related proxy records, have been qualitative, relying on 'curve-fitting' methods. Here, we seek a quantitative approach for identifying coupling relationships between paleoclimate proxy records, employing statistical techniques to compute the interdependence of two paleoclimate time series. We verify the use of complex networks to identify coupling relationships between modern climate indices. This method is then extended to a set of paleoclimate proxy records from the Asian, Australasian and South American regions spanning the past 9000 years. The resulting networks demonstrate the existence of coupling relationships between regional monsoon systems on millennial time scales, but also highlight the transient nature of teleconnections during this period. In the context of the northwest Australian summer monsoon, we recognise a shift in coupling relationships from strong interhemispheric links with East Asian and ITCZ-related proxy records in the mid-Holocene to significantly weaker coupling in the later Holocene. Although the identified links cannot explain the underlying physical processes leading to coupling between regional monsoon systems, this method provides a step towards understanding the role that changes in teleconnections play in millennial-to orbital-scale climate variability.

  4. The Monsoon Erosion Pump and the Indian Monsoon since Eocene

    Science.gov (United States)

    Giosan, L.

    2017-12-01

    Lack of consensus on the Neogene establishment and evolution of the Indian Monsoon is remarkable after half a century of research. Conflicting interpretations point toward the possibility of periodic decoupling between monsoon winds and monsoon precipitation. Here I introduce the concept of a monsoon erosion pump based on terrestrial and oceanic records reconstructed from recent NGHP and IODP drilling and spanning the last 34 million years in the Bay of Bengal, Arabian and Andaman Seas. From millennial to orbital to tectonic timescales, these records suggest that vegetation land cover interacts and modulates the regime of erosion and weathering under perennial but variable monsoonal rain conditions. Under this new proposed paradigm the Indian monsoon exhibits two distinct flavours during the Neogene that can be largely explained by its heartbeat, or astronomical forcing, mediated by the global glacial state and interacting with the paleogeography of South Asia.

  5. Vegetation Variability And Its Effect On Monsoon Rainfall Over South East Asia: Observational and Modeling Results

    Science.gov (United States)

    Sarkar, S.; Peters-Lidard, C.; Chiu, L.; Kafatos, M.

    2005-12-01

    Increasing population and urbanization have created stress on developing nations. The quickly shifting patterns of vegetation change in different parts of the world have given rise to the pertinent question of feedback on the climate prevailing on local to regional scales. It is now known with some certainty, that vegetation changes can affect the climate by influencing the heat and water balance. The hydrological cycle particularly is susceptible to changes in vegetation. The Monsoon rainfall forms a vital link in the hydrological cycle prevailing over South East Asia This work examines the variability of vegetation over South East Asia and assesses its impact on the monsoon rainfall. We explain the role of changing vegetation and show how this change has affected the heat and energy balance. We demonstrate the role of vegetation one season earlier in influencing rainfall intensity over specific areas in South East Asia and show the ramification of vegetation change on the summer rainfall behavior. The vegetation variability study specifically focuses on India and China, two of the largest and most populous nations. We have done an assessment to find out the key meteorological and human induced parameters affecting vegetation over the study area through a spatial analysis of monthly NDVI values. This study highlights the role of monsoon rainfall, regional climate dynamics and large scale human induced pollution to be the crucial factors governing the vegetation and vegetation distribution. The vegetation is seen to follow distinct spatial patterns that have been found to be crucial in its eventual impact on monsoon rainfall. We have carried out a series of sensitivity experiments using a land surface hydrologic modeling scheme. The vital energy and water balance parameters are identified and the daily climatological cycles are examined for possible change in behavior for different boundary conditions. It is found that the change from native deciduous forest

  6. Decadal Monsoon-ENSO Relationships Reexamined

    Science.gov (United States)

    Yun, Kyung-Sook; Timmermann, Axel

    2018-02-01

    The strength of the El Niño-Southern Oscillation (ENSO)-Indian summer monsoon rainfall (ISMR) relationship shows considerable decadal fluctuations, which have been previously linked to low-frequency climatic processes such as shifts in ENSO's center of action or the Atlantic Multidecadal Oscillation. However, random variability can also cause similar variations in the relationship between climate phenomena. Here we propose a statistical test to determine whether the observed time-evolving correlations between ENSO and ISMR are different from those expected from a simple stochastic null hypothesis model. The analysis focuses on the time evolution of moving correlations, their expected variance, and probabilities for rapid transitions. The results indicate that the time evolution of the observed running correlation between these climate modes is indistinguishable from a system in which the ISMR signal can be expressed as a stochastically perturbed ENSO signal. This challenges previous deterministic interpretations. Our results are further corroborated by the analysis of climate model simulations.

  7. Precipitation stable isotope records from the northern Hengduan Mountains in China capture signals of the winter India-Burma Trough and the Indian Summer Monsoon

    Science.gov (United States)

    Yu, Wusheng; Tian, Lide; Yao, Tandong; Xu, Baiqing; Wei, Feili; Ma, Yaoming; Zhu, Haifeng; Luo, Lun; Qu, Dongmei

    2017-11-01

    This project reports results of the first precipitation stable isotope (δ18 O and δD) time series produced for Qamdo in the northern Hengduan Mountains in the southeastern Tibetan Plateau. The data showed that the fluctuations of precipitation stable isotopes at Qamdo during the different seasons revealed various moisture sources. The westerlies and local recycling moisture dominated at the study area before the pre-monsoon and after the post-monsoon seasons, which resulted in similar trends of both precipitation stable isotopes and temperature. The marine moisture was transported to the northern Hengduan Mountains by the winter India-Burma Trough combined with convection. Consequently, stable isotopes in subsequent precipitation were occasionally observed to decrease suddenly. However, δ18 O and δD values of precipitation at Qamdo were lower during the monsoon period and the duration of those low values was longer because of the effects of the Indian Summer Monsoon and the strengthening convection. Our findings indicate that the effects of seasonal precipitation differences caused by various climate systems, including the winter India-Burma Trough and Indian Summer Monsoon, need to be considered when attempting to interpret tree-ring and ice core records for the Hengduan Mountains.

  8. A Holocene Record of Monsoon Intensity From Speleothems in Flores, Indonesia

    Science.gov (United States)

    Griffiths, M. L.; Drysdale, R.; Gagan, M.; Ayliffe, L.; Zhao, J.; St. Pierre, E.; Hantoro, W.; Suwargadi, B.

    2007-12-01

    , correspond with higher (lower) δ13C values. An exception to this correlation is the abrupt shift towards higher δ13C values at approximately 1500 years BP, which does not correspond with the sunspot trend. This result may be indicative of a major volcanic eruption or the clearing of vegetation by modern humans; metal tools were introduced into the area just prior to this change. Given the lack of accurately dated palaeoclimate time series from the Australasian region, there is an urgent need for high-resolution records covering periods of known environmental change. Results from our study will contribute to a better understanding of tropical palaeoclimates and help scientists gain a clearer understanding of the mechanisms driving the changes in the Australasian monsoon system during the Holocene. Lastly, following the recent discovery of the `Hobbit' in a cave just a short distance from Liang Luar, there is scope for studying climatic conditions for the region around the time of the Hobbit's demise.

  9. Improving the interpretability of climate landscape metrics: An ecological risk analysis of Japan's Marine Protected Areas.

    Science.gov (United States)

    García Molinos, Jorge; Takao, Shintaro; Kumagai, Naoki H; Poloczanska, Elvira S; Burrows, Michael T; Fujii, Masahiko; Yamano, Hiroya

    2017-10-01

    Conservation efforts strive to protect significant swaths of terrestrial, freshwater and marine ecosystems from a range of threats. As climate change becomes an increasing concern, these efforts must take into account how resilient-protected spaces will be in the face of future drivers of change such as warming temperatures. Climate landscape metrics, which signal the spatial magnitude and direction of climate change, support a convenient initial assessment of potential threats to and opportunities within ecosystems to inform conservation and policy efforts where biological data are not available. However, inference of risk from purely physical climatic changes is difficult unless set in a meaningful ecological context. Here, we aim to establish this context using historical climatic variability, as a proxy for local adaptation by resident biota, to identify areas where current local climate conditions will remain extant and future regional climate analogues will emerge. This information is then related to the processes governing species' climate-driven range edge dynamics, differentiating changes in local climate conditions as promoters of species range contractions from those in neighbouring locations facilitating range expansions. We applied this approach to assess the future climatic stability and connectivity of Japanese waters and its network of marine protected areas (MPAs). We find 88% of Japanese waters transitioning to climates outside their historical variability bounds by 2035, resulting in large reductions in the amount of available climatic space potentially promoting widespread range contractions and expansions. Areas of high connectivity, where shifting climates converge, are present along sections of the coast facilitated by the strong latitudinal gradient of the Japanese archipelago and its ocean current system. While these areas overlap significantly with areas currently under significant anthropogenic pressures, they also include much of the MPA

  10. Areas of climate stability of species ranges in the Brazilian Cerrado

    DEFF Research Database (Denmark)

    Terribile, Levi Carina; Lima-Ribeiro, Matheus Souza; Bastos Araujo, Miguel

    2012-01-01

    uncertainties and to identify climatically stable areas, working with Cerrado tree species as a model organism. Ecological niche models were generated for 18 Cerrado tree species and their potential distributions were projected into past and future. Analyses of the sources of uncertainties in ensembles...... continuous climatically stable area was identified, which should be considered as a potential improvement for spatial prioritization for conservation....

  11. Indian Summer Monsoon Rainfall: Implications of Contrasting Trends in the Spatial Variability of Means and Extremes

    Science.gov (United States)

    Ghosh, Subimal; Vittal, H.; Sharma, Tarul; Karmakar, Subhankar; Kasiviswanathan, K. S.; Dhanesh, Y.; Sudheer, K. P.; Gunthe, S. S.

    2016-01-01

    India’s agricultural output, economy, and societal well-being are strappingly dependent on the stability of summer monsoon rainfall, its variability and extremes. Spatial aggregate of intensity and frequency of extreme rainfall events over Central India are significantly increasing, while at local scale they are spatially non-uniform with increasing spatial variability. The reasons behind such increase in spatial variability of extremes are poorly understood and the trends in mean monsoon rainfall have been greatly overlooked. Here, by using multi-decadal gridded daily rainfall data over entire India, we show that the trend in spatial variability of mean monsoon rainfall is decreasing as exactly opposite to that of extremes. The spatial variability of extremes is attributed to the spatial variability of the convective rainfall component. Contrarily, the decrease in spatial variability of the mean rainfall over India poses a pertinent research question on the applicability of large scale inter-basin water transfer by river inter-linking to address the spatial variability of available water in India. We found a significant decrease in the monsoon rainfall over major water surplus river basins in India. Hydrological simulations using a Variable Infiltration Capacity (VIC) model also revealed that the water yield in surplus river basins is decreasing but it is increasing in deficit basins. These findings contradict the traditional notion of dry areas becoming drier and wet areas becoming wetter in response to climate change in India. This result also calls for a re-evaluation of planning for river inter-linking to supply water from surplus to deficit river basins. PMID:27463092

  12. Indian Summer Monsoon Rainfall: Implications of Contrasting Trends in the Spatial Variability of Means and Extremes.

    Directory of Open Access Journals (Sweden)

    Subimal Ghosh

    Full Text Available India's agricultural output, economy, and societal well-being are strappingly dependent on the stability of summer monsoon rainfall, its variability and extremes. Spatial aggregate of intensity and frequency of extreme rainfall events over Central India are significantly increasing, while at local scale they are spatially non-uniform with increasing spatial variability. The reasons behind such increase in spatial variability of extremes are poorly understood and the trends in mean monsoon rainfall have been greatly overlooked. Here, by using multi-decadal gridded daily rainfall data over entire India, we show that the trend in spatial variability of mean monsoon rainfall is decreasing as exactly opposite to that of extremes. The spatial variability of extremes is attributed to the spatial variability of the convective rainfall component. Contrarily, the decrease in spatial variability of the mean rainfall over India poses a pertinent research question on the applicability of large scale inter-basin water transfer by river inter-linking to address the spatial variability of available water in India. We found a significant decrease in the monsoon rainfall over major water surplus river basins in India. Hydrological simulations using a Variable Infiltration Capacity (VIC model also revealed that the water yield in surplus river basins is decreasing but it is increasing in deficit basins. These findings contradict the traditional notion of dry areas becoming drier and wet areas becoming wetter in response to climate change in India. This result also calls for a re-evaluation of planning for river inter-linking to supply water from surplus to deficit river basins.

  13. Climate model performance and change projection for freshwater fluxes: Comparison for irrigated areas in Central and South Asia

    Directory of Open Access Journals (Sweden)

    Shilpa M. Asokan

    2016-03-01

    Full Text Available Study region: The large semi-arid Aral Region in Central Asia and the smaller tropical Mahanadi River Basin (MRB in India. Study focus: Few studies have so far evaluated the performance of the latest generation of global climate models on hydrological basin scales. We here investigate the performance and projections of the global climate models in the Coupled Model Intercomparison Project, Phase 5 (CMIP5 for freshwater fluxes and their changes in two regional hydrological basins, which are both irrigated but of different scale and with different climate. New hydrological insights for the region: For precipitation in both regions, model accuracy relative to observations has remained the same or decreased in successive climate model generations until and including CMIP5. No single climate model out-performs other models across all key freshwater variables in any of the investigated basins. Scale effects are not evident from global model application directly to freshwater assessment for the two basins of widely different size. Overall, model results are less accurate and more uncertain for freshwater fluxes than for temperature, and particularly so for model-implied water storage changes. Also, the monsoon-driven runoff seasonality in MRB is not accurately reproduced. Model projections agree on evapotranspiration increase in both regions until the climatic period 2070–2099. This increase is fed by precipitation increase in MRB and by runoff water (thereby decreasing runoff in the Aral Region. Keywords: CMIP5 global climate models, Hydro-climate, Freshwater change, Central Asia, South Asia, Monsoon driven seasonality

  14. Climate change, habitat loss, protected areas and the climate adaptation potential of species in mediterranean ecosystems worldwide.

    Directory of Open Access Journals (Sweden)

    Kirk R Klausmeyer

    Full Text Available Mediterranean climate is found on five continents and supports five global biodiversity hotspots. Based on combined downscaled results from 23 atmosphere-ocean general circulation models (AOGCMs for three emissions scenarios, we determined the projected spatial shifts in the mediterranean climate extent (MCE over the next century. Although most AOGCMs project a moderate expansion in the global MCE, regional impacts are large and uneven. The median AOGCM simulation output for the three emissions scenarios project the MCE at the end of the 21(st century in Chile will range from 129-153% of its current size, while in Australia, it will contract to only 77-49% of its current size losing an area equivalent to over twice the size of Portugal. Only 4% of the land area within the current MCE worldwide is in protected status (compared to a global average of 12% for all biome types, and, depending on the emissions scenario, only 50-60% of these protected areas are likely to be in the future MCE. To exacerbate the climate impact, nearly one third (29-31% of the land where the MCE is projected to remain stable has already been converted to human use, limiting the size of the potential climate refuges and diminishing the adaptation potential of native biota. High conversion and low protection in projected stable areas make Australia the highest priority region for investment in climate-adaptation strategies to reduce the threat of climate change to the rich biodiversity of the mediterranean biome.

  15. Protected area networks and savannah bird biodiversity in the face of climate change and land degradation.

    Science.gov (United States)

    Beale, Colin M; Baker, Neil E; Brewer, Mark J; Lennon, Jack J

    2013-08-01

    The extent to which climate change might diminish the efficacy of protected areas is one of the most pressing conservation questions. Many projections suggest that climate-driven species distribution shifts will leave protected areas impoverished and species inadequately protected while other evidence suggests that intact ecosystems within protected areas will be resilient to change. Here, we tackle this problem empirically. We show how recent changes in distribution of 139 Tanzanian savannah bird species are linked to climate change, protected area status and land degradation. We provide the first evidence of climate-driven range shifts for an African bird community. Our results suggest that the continued maintenance of existing protected areas is an appropriate conservation response to the challenge of climate and environmental change. © 2013 John Wiley & Sons Ltd/CNRS.

  16. Testing a flexible method to reduce false monsoon onsets.

    Directory of Open Access Journals (Sweden)

    Mathew Alexander Stiller-Reeve

    Full Text Available To generate information about the monsoon onset and withdrawal we have to choose a monsoon definition and apply it to data. One problem that arises is that false monsoon onsets can hamper our analysis, which is often alleviated by smoothing the data in time or space. Another problem is that local communities or stakeholder groups may define the monsoon differently. We therefore aim to develop a technique that reduces false onsets for high-resolution gridded data, while also being flexible for different requirements that can be tailored to particular end-users. In this study, we explain how we developed our technique and demonstrate how it successfully reduces false onsets and withdrawals. The presented results yield improved information about the monsoon length and its interannual variability. Due to this improvement, we are able to extract information from higher resolution data sets. This implies that we can potentially get a more detailed picture of local climate variations that can be used in more local climate application projects such as community-based adaptations.

  17. Global monsoon precipitation responses to large volcanic eruptions

    Science.gov (United States)

    Liu, Fei; Chai, Jing; Wang, Bin; Liu, Jian; Zhang, Xiao; Wang, Zhiyuan

    2016-01-01

    Climate variation of global monsoon (GM) precipitation involves both internal feedback and external forcing. Here, we focus on strong volcanic forcing since large eruptions are known to be a dominant mechanism in natural climate change. It is not known whether large volcanoes erupted at different latitudes have distinctive effects on the monsoon in the Northern Hemisphere (NH) and the Southern Hemisphere (SH). We address this issue using a 1500-year volcanic sensitivity simulation by the Community Earth System Model version 1.0 (CESM1). Volcanoes are classified into three types based on their meridional aerosol distributions: NH volcanoes, SH volcanoes and equatorial volcanoes. Using the model simulation, we discover that the GM precipitation in one hemisphere is enhanced significantly by the remote volcanic forcing occurring in the other hemisphere. This remote volcanic forcing-induced intensification is mainly through circulation change rather than moisture content change. In addition, the NH volcanic eruptions are more efficient in reducing the NH monsoon precipitation than the equatorial ones, and so do the SH eruptions in weakening the SH monsoon, because the equatorial eruptions, despite reducing moisture content, have weaker effects in weakening the off-equatorial monsoon circulation than the subtropical-extratropical volcanoes do. PMID:27063141

  18. Global monsoon precipitation responses to large volcanic eruptions.

    Science.gov (United States)

    Liu, Fei; Chai, Jing; Wang, Bin; Liu, Jian; Zhang, Xiao; Wang, Zhiyuan

    2016-04-11

    Climate variation of global monsoon (GM) precipitation involves both internal feedback and external forcing. Here, we focus on strong volcanic forcing since large eruptions are known to be a dominant mechanism in natural climate change. It is not known whether large volcanoes erupted at different latitudes have distinctive effects on the monsoon in the Northern Hemisphere (NH) and the Southern Hemisphere (SH). We address this issue using a 1500-year volcanic sensitivity simulation by the Community Earth System Model version 1.0 (CESM1). Volcanoes are classified into three types based on their meridional aerosol distributions: NH volcanoes, SH volcanoes and equatorial volcanoes. Using the model simulation, we discover that the GM precipitation in one hemisphere is enhanced significantly by the remote volcanic forcing occurring in the other hemisphere. This remote volcanic forcing-induced intensification is mainly through circulation change rather than moisture content change. In addition, the NH volcanic eruptions are more efficient in reducing the NH monsoon precipitation than the equatorial ones, and so do the SH eruptions in weakening the SH monsoon, because the equatorial eruptions, despite reducing moisture content, have weaker effects in weakening the off-equatorial monsoon circulation than the subtropical-extratropical volcanoes do.

  19. Asian monsoons in a late Eocene greenhouse world.

    Science.gov (United States)

    Licht, A; van Cappelle, M; Abels, H A; Ladant, J-B; Trabucho-Alexandre, J; France-Lanord, C; Donnadieu, Y; Vandenberghe, J; Rigaudier, T; Lécuyer, C; Terry, D; Adriaens, R; Boura, A; Guo, Z; Soe, Aung Naing; Quade, J; Dupont-Nivet, G; Jaeger, J-J

    2014-09-25

    The strong present-day Asian monsoons are thought to have originated between 25 and 22 million years (Myr) ago, driven by Tibetan-Himalayan uplift. However, the existence of older Asian monsoons and their response to enhanced greenhouse conditions such as those in the Eocene period (55-34 Myr ago) are unknown because of the paucity of well-dated records. Here we show late Eocene climate records revealing marked monsoon-like patterns in rainfall and wind south and north of the Tibetan-Himalayan orogen. This is indicated by low oxygen isotope values with strong seasonality in gastropod shells and mammal teeth from Myanmar, and by aeolian dust deposition in northwest China. Our climate simulations support modern-like Eocene monsoonal rainfall and show that a reinforced hydrological cycle responding to enhanced greenhouse conditions counterbalanced the negative effect of lower Tibetan relief on precipitation. These strong monsoons later weakened with the global shift to icehouse conditions 34 Myr ago.

  20. Deglaciation in the tropical Indian Ocean driven by interplay between the regional monsoon and global teleconnections

    Digital Repository Service at National Institute of Oceanography (India)

    Saraswat, R.; Lea, D.W.; Nigam, R.; Mackensen, A.; Naik, Dinesh K.

    High resolution climate records of the ice age terminations from monsoon-dominated regions reveal the interplay of regional and global driving forces. Speleothem records from Chinese caves indicate that glacial terminations were interrupted...

  1. Monsoonal reversal of remote sensing biases in latent heat flux over eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Muraleedharan, P.M.; Pankajakshan, T.; Sathe, P.V.; Murty, V.S.N.; Santosh, K.R.

    The Arabian Sea is a unique basin where a number of atmospheric and oceanographic processes occur due to the contrasting climatic conditions, which it experiences. The drastic monsoonal variability occurring in the boundary layer adversely affects...

  2. Climate Influence on Emerging Risk Areas for Rift Valley Fever Epidemics in Tanzania.

    Science.gov (United States)

    Mweya, Clement N; Mboera, Leonard E G; Kimera, Sharadhuli I

    2017-07-01

    Rift Valley Fever (RVF) is a climate-related arboviral infection of animals and humans. Climate is thought to represent a threat toward emerging risk areas for RVF epidemics globally. The objective of this study was to evaluate influence of climate on distribution of suitable breeding habitats for Culex pipiens complex, potential mosquito vector responsible for transmission and distribution of disease epidemics risk areas in Tanzania. We used ecological niche models to estimate potential distribution of disease risk areas based on vectors and disease co-occurrence data approach. Climatic variables for the current and future scenarios were used as model inputs. Changes in mosquito vectors' habitat suitability in relation to disease risk areas were estimated. We used partial receiver operating characteristic and the area under the curves approach to evaluate model predictive performance and significance. Habitat suitability for Cx. pipiens complex indicated broad-scale potential for change and shift in the distribution of the vectors and disease for both 2020 and 2050 climatic scenarios. Risk areas indicated more intensification in the areas surrounding Lake Victoria and northeastern part of the country through 2050 climate scenario. Models show higher probability of emerging risk areas spreading toward the western parts of Tanzania from northeastern areas and decrease in the southern part of the country. Results presented here identified sites for consideration to guide surveillance and control interventions to reduce risk of RVF disease epidemics in Tanzania. A collaborative approach is recommended to develop and adapt climate-related disease control and prevention strategies.

  3. Characteristics of monsoon waves off Uran, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Nayak, B.U.; Chandramohan, P.; Mandal, S.

    's and the spectral methods for determining various wave parameters. Monsoon wave climate was stronger with the occurrence of the highest significant wave height of 2.45 m and the corresponding maximum wave height of 3.9 m in July. Significant wave height varied from...

  4. Simulation of Indian summer monsoon using the Japan ...

    Indian Academy of Sciences (India)

    Simulation of Indian summer monsoon using the Japan Meteorological Agency's seasonal ensemble prediction system. Kailas Sonawane1,∗. , O P Sreejith1, D R Pattanaik1,. Mahendra Benke1, Nitin Patil2 and D S Pai1. 1India Meteorological Department, Pune 411 005, India. 2Interdisciplinary Programme in Climate ...

  5. Late Quaternary climatic changes in the Ross Sea area, Antarctica

    International Nuclear Information System (INIS)

    Brambati, A.; Melis, R.; Quaia, T.; Salvi, G.

    2002-01-01

    Ten cores from the Ross Sea continental margin were investigated to detect Late Quaternary climatic changes. Two main climatic cycles over the last 300,000 yr (isotope stages 1-8) were recognised in cores from the continental slope, whereas minor fluctuations over the last 30,000 yr were found in cores from the continental shelf. The occurrence of calcareous taxa within the Last Glacial interval and their subsequent disappearance reveal a general raising of the CCD during the last climatic cycle. In addition, periodical trends of c. 400, c. 700, and c. 1400 yr determined on calcareous foraminifers from sediments of the Joides Basin, indicate fluctuations of the Ross Ice Shelf between 15 and 30 ka BP. (author). 24 refs., 5 figs

  6. Modelling Monsoons: Understanding and Predicting Current and Future Behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Turner, A; Sperber, K R; Slingo, J M; Meehl, G A; Mechoso, C R; Kimoto, M; Giannini, A

    2008-09-16

    The global monsoon system is so varied and complex that understanding and predicting its diverse behaviour remains a challenge that will occupy modellers for many years to come. Despite the difficult task ahead, an improved monsoon modelling capability has been realized through the inclusion of more detailed physics of the climate system and higher resolution in our numerical models. Perhaps the most crucial improvement to date has been the development of coupled ocean-atmosphere models. From subseasonal to interdecadal timescales, only through the inclusion of air-sea interaction can the proper phasing and teleconnections of convection be attained with respect to sea surface temperature variations. Even then, the response to slow variations in remote forcings (e.g., El Nino-Southern Oscillation) does not result in a robust solution, as there are a host of competing modes of variability that must be represented, including those that appear to be chaotic. Understanding the links between monsoons and land surface processes is not as mature as that explored regarding air-sea interactions. A land surface forcing signal appears to dominate the onset of wet season rainfall over the North American monsoon region, though the relative role of ocean versus land forcing remains a topic of investigation in all the monsoon systems. Also, improved forecasts have been made during periods in which additional sounding observations are available for data assimilation. Thus, there is untapped predictability that can only be attained through the development of a more comprehensive observing system for all monsoon regions. Additionally, improved parameterizations - for example, of convection, cloud, radiation, and boundary layer schemes as well as land surface processes - are essential to realize the full potential of monsoon predictability. Dynamical considerations require ever increased horizontal resolution (probably to 0.5 degree or higher) in order to resolve many monsoon features

  7. Scale-dependent complementarity of climatic velocity and environmental diversity for identifying priority areas for conservation under climate change.

    Science.gov (United States)

    Carroll, Carlos; Roberts, David R; Michalak, Julia L; Lawler, Joshua J; Nielsen, Scott E; Stralberg, Diana; Hamann, Andreas; Mcrae, Brad H; Wang, Tongli

    2017-11-01

    As most regions of the earth transition to altered climatic conditions, new methods are needed to identify refugia and other areas whose conservation would facilitate persistence of biodiversity under climate change. We compared several common approaches to conservation planning focused on climate resilience over a broad range of ecological settings across North America and evaluated how commonalities in the priority areas identified by different methods varied with regional context and spatial scale. Our results indicate that priority areas based on different environmental diversity metrics differed substantially from each other and from priorities based on spatiotemporal metrics such as climatic velocity. Refugia identified by diversity or velocity metrics were not strongly associated with the current protected area system, suggesting the need for additional conservation measures including protection of refugia. Despite the inherent uncertainties in predicting future climate, we found that variation among climatic velocities derived from different general circulation models and emissions pathways was less than the variation among the suite of environmental diversity metrics. To address uncertainty created by this variation, planners can combine priorities identified by alternative metrics at a single resolution and downweight areas of high variation between metrics. Alternately, coarse-resolution velocity metrics can be combined with fine-resolution diversity metrics in order to leverage the respective strengths of the two groups of metrics as tools for identification of potential macro- and microrefugia that in combination maximize both transient and long-term resilience to climate change. Planners should compare and integrate approaches that span a range of model complexity and spatial scale to match the range of ecological and physical processes influencing persistence of biodiversity and identify a conservation network resilient to threats operating at

  8. Simulation of Crop Growth and Water-Saving Irrigation Scenarios for Lettuce: A Monsoon-Climate Case Study in Kampong Chhnang, Cambodia

    Directory of Open Access Journals (Sweden)

    Pinnara Ket

    2018-05-01

    Full Text Available Setting up water-saving irrigation strategies is a major challenge farmers face, in order to adapt to climate change and to improve water-use efficiency in crop productions. Currently, the production of vegetables, such as lettuce, poses a greater challenge in managing effective water irrigation, due to their sensitivity to water shortage. Crop growth models, such as AquaCrop, play an important role in exploring and providing effective irrigation strategies under various environmental conditions. The objectives of this study were (i to parameterise the AquaCrop model for lettuce (Lactuca sativa var. crispa L. using data from farmers’ fields in Cambodia, and (ii to assess the impact of two distinct full and deficit irrigation scenarios in silico, using AquaCrop, under two contrasting soil types in the Cambodian climate. Field observations of biomass and canopy cover during the growing season of 2017 were used to adjust the crop growth parameters of the model. The results confirmed the ability of AquaCrop to correctly simulate lettuce growth. The irrigation scenario analysis suggested that deficit irrigation is a “silver bullet” water saving strategy that can save 20–60% of water compared to full irrigation scenarios in the conditions of this study.

  9. Projected change in East Asian summer monsoon by dynamic downscaling: Moisture budget analysis

    Science.gov (United States)

    Jung, Chun-Yong; Shin, Ho-Jeong; Jang, Chan Joo; Kim, Hyung-Jin

    2015-02-01

    The summer monsoon considerably affects water resource and natural hazards including flood and drought in East Asia, one of the world's most densely populated area. In this study, we investigate future changes in summer precipitation over East Asia induced by global warming through dynamical downscaling with the Weather Research and Forecast model. We have selected a global model from the Coupled Model Intercomparison Project Phase 5 based on an objective evaluation for East Asian summer monsoon and applied its climate change under Representative Concentration Pathway 4.5 scenario to a pseudo global warming method. Unlike the previous studies that focused on a qualitative description of projected precipitation changes over East Asia, this study tried to identify the physical causes of the precipitation changes by analyzing a local moisture budget. Projected changes in precipitation over the eastern foothills area of Tibetan Plateau including Sichuan Basin and Yangtze River displayed a contrasting pattern: a decrease in its northern area and an increase in its southern area. A local moisture budget analysis indicated the precipitation increase over the southern area can be mainly attributed to an increase in horizontal wind convergence and surface evaporation. On the other hand, the precipitation decrease over the northern area can be largely explained by horizontal advection of dry air from the northern continent and by divergent wind flow. Regional changes in future precipitation in East Asia are likely to be attributed to different mechanisms which can be better resolved by regional dynamical downscaling.

  10. Adaptation to climate change in urban areas: climate-greening London, Rotterdam, and Toronto

    NARCIS (Netherlands)

    Mees, H.L.P.; Driessen, P.P.J.

    2011-01-01

    This article aims to gain insight into the governance capacity of cities to adapt to climate change through urban green planning, which we will refer to as climate-greening. The use of green space is considered a no-regrets adaptation strategy, since it not only absorbs rainfall and

  11. Northern protected areas will become important refuges for biodiversity tracking suitable climates.

    Science.gov (United States)

    Berteaux, Dominique; Ricard, Marylène; St-Laurent, Martin-Hugues; Casajus, Nicolas; Périé, Catherine; Beauregard, Frieda; de Blois, Sylvie

    2018-03-15

    The Northern Biodiversity Paradox predicts that, despite its globally negative effects on biodiversity, climate change will increase biodiversity in northern regions where many species are limited by low temperatures. We assessed the potential impacts of climate change on the biodiversity of a northern network of 1,749 protected areas spread over >600,000 km 2 in Quebec, Canada. Using ecological niche modeling, we calculated potential changes in the probability of occurrence of 529 species to evaluate the potential impacts of climate change on (1) species gain, loss, turnover, and richness in protected areas, (2) representativity of protected areas, and (3) extent of species ranges located in protected areas. We predict a major species turnover over time, with 49% of total protected land area potentially experiencing a species turnover >80%. We also predict increases in regional species richness, representativity of protected areas, and species protection provided by protected areas. Although we did not model the likelihood of species colonising habitats that become suitable as a result of climate change, northern protected areas should ultimately become important refuges for species tracking climate northward. This is the first study to examine in such details the potential effects of climate change on a northern protected area network.

  12. Ecoclimatic indicators to study climate suitability of areas for the cultivation of specific crops

    Science.gov (United States)

    Caubel, J.; Garcia de Cortazar Atauri, I.; Cufi, J.; Huard, F.; Launay, M.; Ripoche, D.; Graux, A.; deNoblet, N.

    2013-12-01

    Climatic conditions play a fundamental role in the suitability of geographical areas for cropping. In the context of climate change, we could expect changes in overall climatic conditions and so, on the suitability for cropping. Therefore, assessing the future climate suitability of areas for cropping is decisive for anticipating agriculture in a given area. Moreover, it is crucial to have access to the split up information concerning the effect of climate on the achievement of the main ecophysiological processes and cultural practices taking place during the crop cycle. In this way, stakeholders can envisage land use adaptations under climate change conditions, such as changes in cultural practices or development of new varieties for example. We proposed an aggregation tool of ecoclimatic indicators to design evaluation trees of climate suitability of areas for cropping, GETARI (Generic Evaluation Tool of Ecoclimatic Indicators). It calculates an overall climate suitability index at the annual scale, from a designed evaluation tree. This aggregation tool allows to characterize climate suitability according to crop ecophysiology, grain/fruit quality or crop management. GETARI proposes the major ecophysiological processes and cultural practices taking place during phenological periods, together with the climatic effects that are known to affect their achievement. The climatic effects on the ecophysiological processes (or cultural practices) during phenological periods 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. Those indices of suitability are normalized and aggregated according to aggregation rules in order to compute an overall climate index. In order to illustrate how GETARI can be used, we designed evaluation trees in order to study the climate suitability for maize cropping regarding

  13. Variation in the Asian monsoon intensity and dry-wet condition since the Little Ice Age in central China revealed by an aragonite stalagmite

    Science.gov (United States)

    Yin, J.-J.; Yuan, D.-X.; Li, H.-C.; Cheng, H.; Li, T.-Y.; Edwards, R. L.; Lin, Y.-S.; Qin, J.-M.; Tang, W.; Zhao, Z.-Y.; Mii, H.-S.

    2014-04-01

    Highlight: this paper focuses on the climate variability in central China since 1300 AD, involving: 1. A well-dated, 1.5 year resolution stalagmite δ18O record from Lianhua Cave, central China; 2. Links of the δ18O record with regional dry-wet condition, monsoon intensity, and temperature over eastern China; 3. Correlations among drought events in the Lianhua record, solar irradiation, and ENSO index. We present a highly precisely 230Th/U dated, 1.5 year resolution δ18O record of an aragonite stalagmite (LHD1) collected from Lianhua Cave in Wuling mountain area of central China. The comparison of the δ18O record with the local instrumental record and historical documents exhibits at least 15 drought events in the Wuling mountain and adjacent areas during the Little Ice Age, in which some of them were corresponding to megadrought events in the broad Asian monsoonal region of China. Thus, the stalagmite δ18O record reveals variations in the summer monsoon precipitation and dry-wet condition in Wuling mountain area. The eastern China temperature varied with the solar activity, showing higher temperature under stronger solar irradiation which produces stronger summer monsoon. During Maunder, Dalton and 1900 sunspot minima, more severe drought events occurred, indicating weakening of the summer monsoon when solar activity decreased on decadal time scales. On interannual time scale, dry conditions in the studying area were prevailing under El Niño condition, which is also supported by the spectrum analysis. Hence, our record illustrates the linkage of Asian summer monsoon precipitation to solar irradiation and ENSO: wetter condition under stronger summer monsoon during warm periods and vice versa; During cold periods, the Walker circulation will shift toward central Pacific under El Niño condition, resulting further weakening of Asian summer monsoon. However, the δ18O of LHD1 record is positively correlated with temperature after ~1940 AD which is opposite to the

  14. Impact of climate change on the stream flow of the lower Brahmaputra: Trends in high and low flows based on discharge-weighted ensemble modelling

    NARCIS (Netherlands)

    Gain, A.K.; Immerzeel, W.W.; Sperna Weiland, F.C.; Bierkens, M.F.P.

    2011-01-01

    Climate change is likely to have significant effects on the hydrology. The Ganges-Brahmaputra river basin is one of the most vulnerable areas in the world as it is subject to the combined effects of glacier melt, extreme monsoon rainfall and sea level rise. To what extent climate change will impact

  15. Water in Urban Areas in a Climate Change Perspective

    DEFF Research Database (Denmark)

    Arnbjerg-Nielsen, Karsten

    2012-01-01

    Climatic changes will influence the water cycle substantially. This will have an immediate impact on the performance of urban water infrastructure. A case study from Roskilde shows that assuming an increase in design intensities of 40 % over a 100 year horizon will lead to increased cost of indiv......Climatic changes will influence the water cycle substantially. This will have an immediate impact on the performance of urban water infrastructure. A case study from Roskilde shows that assuming an increase in design intensities of 40 % over a 100 year horizon will lead to increased cost...... of individual very extreme events (e.g. more than 100 years) of approximately 70 % and a 900 % increase in the expected annual losses due to floods. Other case studies in Denmark show smaller impacts, but still very significant increased annual costs compared to the present state. This calls for systematic...

  16. The rise of the Himalaya enforced the diversification of SE Asian ferns by altering the monsoon regimes

    Directory of Open Access Journals (Sweden)

    Wang Li

    2012-11-01

    Full Text Available Abstract Background The rise of high mountain chains is widely seen as one of the factors driving rapid diversification of land plants and the formation of biodiversity hotspots. Supporting evidence was reported for the impact of the rapid rise of the Andean mountains but this hypothesis has so far been less explored for the impact of the “roof of the world”. The formation of the Himalaya, and especially the rise of the Qinghai–Tibetan Plateau in the recent 20 million years, altered the monsoon regimes that dominate the current climates of South East Asia. Here, we infer the hypothesis that the rise of Himalaya had a strong impact on the plant diversity in the biodiversity hotspot of the Southwest Chinese Mountains. Results Our analyses of the diversification pattern of the derived fern genus Lepisorus recovered evidence for changes in plant diversity that correlated with the strengthening of South East Asian monsoon. Southwest China or Southwest China and Japan was recovered as the putative area of origin of Lepisorus and enhancing monsoon regime were found to shape the early diversification of the genus as well as subsequent radiations during the late Miocene and Pliocene. Conclusions We report new evidence for a coincidence of plant diversification and changes of the climate caused by the uplift of the Himalaya. These results are discussed in the context of the impact of incomplete taxon sampling, uncertainty of divergence time estimates, and limitations of current methods used to assess diversification rates.

  17. The rise of the Himalaya enforced the diversification of SE Asian ferns by altering the monsoon regimes.

    Science.gov (United States)

    Wang, Li; Schneider, Harald; Zhang, Xian-Chun; Xiang, Qiao-Ping

    2012-11-09

    The rise of high mountain chains is widely seen as one of the factors driving rapid diversification of land plants and the formation of biodiversity hotspots. Supporting evidence was reported for the impact of the rapid rise of the Andean mountains but this hypothesis has so far been less explored for the impact of the "roof of the world". The formation of the Himalaya, and especially the rise of the Qinghai-Tibetan Plateau in the recent 20 million years, altered the monsoon regimes that dominate the current climates of South East Asia. Here, we infer the hypothesis that the rise of Himalaya had a strong impact on the plant diversity in the biodiversity hotspot of the Southwest Chinese Mountains. Our analyses of the diversification pattern of the derived fern genus Lepisorus recovered evidence for changes in plant diversity that correlated with the strengthening of South East Asian monsoon. Southwest China or Southwest China and Japan was recovered as the putative area of origin of Lepisorus and enhancing monsoon regime were found to shape the early diversification of the genus as well as subsequent radiations during the late Miocene and Pliocene. We report new evidence for a coincidence of plant diversification and changes of the climate caused by the uplift of the Himalaya. These results are discussed in the context of the impact of incomplete taxon sampling, uncertainty of divergence time estimates, and limitations of current methods used to assess diversification rates.

  18. Dirtier Air from a Weaker Monsoon

    Science.gov (United States)

    Chin, Mian

    2012-01-01

    The level of air pollution in China has much increased in the past decades, causing serious health problems. Among the main pollutants are aerosols, also known as particulate matter: tiny, invisible particles that are suspended in the air. These particles contribute substantially to premature mortality associated with cardiopulmonary diseases and lung cancer1. The increase of the aerosol level in China has been commonly attributed to the fast rise in pollutant emissions from the rapid economic development in the region. However, writing in Geophysical Research Letters, Jianlei Zhu and colleagues2 tell a different side of the story: using a chemical transport model and observation data, they show that the decadal scale weakening of the East Asian summer monsoon has also contributed to the increase of aerosol concentrations in China. The life cycle of atmospheric aerosols starts with its emission or formation in the atmosphere. Some aerosol components such as dust, soot and sea salt are emitted directly as particles to the atmosphere, but others are formed there by way of photochemical reactions. For example, sulphate and nitrate aerosols are produced from their respective precursor gases, sulphur dioxide and nitrogen oxides. Aerosol particles can be transported away from their source locations by winds or vertical motion of the air. Eventually, they are removed from the atmosphere by means of dry deposition and wet scavenging by precipitation. Measurements generally show that aerosol concentrations over Asia are lowest during the summer monsoon season3, because intense rainfall efficiently removes them from the air. The East Asian summer monsoon extends over subtropics and mid-latitudes. Its rainfall tends to concentrate in rain belts that stretch out for many thousands of kilometres and affect China, Korea, Japan and the surrounding area. Observations suggest that the East Asian summer monsoon circulation and precipitation have been in decline since the 1970s4. In

  19. Multi-Site and Multi-Variables Statistical Downscaling Technique in the Monsoon Dominated Region of Pakistan

    Science.gov (United States)

    Khan, Firdos; Pilz, Jürgen

    2016-04-01

    South Asia is under the severe impacts of changing climate and global warming. The last two decades showed that climate change or global warming is happening and the first decade of 21st century is considered as the warmest decade over Pakistan ever in history where temperature reached 53 0C in 2010. Consequently, the spatio-temporal distribution and intensity of precipitation is badly effected and causes floods, cyclones and hurricanes in the region which further have impacts on agriculture, water, health etc. To cope with the situation, it is important to conduct impact assessment studies and take adaptation and mitigation remedies. For impact assessment studies, we need climate variables at higher resolution. Downscaling techniques are used to produce climate variables at higher resolution; these techniques are broadly divided into two types, statistical downscaling and dynamical downscaling. The target location of this study is the monsoon dominated region of Pakistan. One reason for choosing this area is because the contribution of monsoon rains in this area is more than 80 % of the total rainfall. This study evaluates a statistical downscaling technique which can be then used for downscaling climatic variables. Two statistical techniques i.e. quantile regression and copula modeling are combined in order to produce realistic results for climate variables in the area under-study. To reduce the dimension of input data and deal with multicollinearity problems, empirical orthogonal functions will be used. Advantages of this new method are: (1) it is more robust to outliers as compared to ordinary least squares estimates and other estimation methods based on central tendency and dispersion measures; (2) it preserves the dependence among variables and among sites and (3) it can be used to combine different types of distributions. This is important in our case because we are dealing with climatic variables having different distributions over different meteorological

  20. Efficient transport of tropospheric aerosol into the stratosphere via the Asian summer monsoon anticyclone

    Science.gov (United States)

    Yu, Pengfei; Rosenlof, Karen H.; Liu, Shang; Telg, Hagen; Thornberry, Troy D.; Rollins, Andrew W.; Portmann, Robert W.; Bai, Zhixuan; Ray, Eric A.; Duan, Yunjun; Pan, Laura L.; Toon, Owen B.; Bian, Jianchun; Gao, Ru-Shan

    2017-07-01

    An enhanced aerosol layer near the tropopause over Asia during the June-September period of the Asian summer monsoon (ASM) was recently identified using satellite observations. Its sources and climate impact are presently not well-characterized. To improve understanding of this phenomenon, we made in situ aerosol measurements during summer 2015 from Kunming, China, then followed with a modeling study to assess the global significance. The in situ measurements revealed a robust enhancement in aerosol concentration that extended up to 2 km above the tropopause. A climate model simulation demonstrates that the abundant anthropogenic aerosol precursor emissions from Asia coupled with rapid vertical transport associated with monsoon convection leads to significant particle formation in the upper troposphere within the ASM anticyclone. These particles subsequently spread throughout the entire Northern Hemispheric (NH) lower stratosphere and contribute significantly (˜15%) to the NH stratospheric column aerosol surface area on an annual basis. This contribution is comparable to that from the sum of small volcanic eruptions in the period between 2000 and 2015. Although the ASM contribution is smaller than that from tropical upwelling (˜35%), we find that this region is about three times as efficient per unit area and time in populating the NH stratosphere with aerosol. With a substantial amount of organic and sulfur emissions in Asia, the ASM anticyclone serves as an efficient smokestack venting aerosols to the upper troposphere and lower stratosphere. As economic growth continues in Asia, the relative importance of Asian emissions to stratospheric aerosol is likely to increase.

  1. Increase in quantity and quality of suitable areas for invasive species as climate changes.

    Science.gov (United States)

    Bertelsmeier, Cleo; Luque, Gloria M; Courchamp, Franck

    2013-12-01

    As climatically suitable range projections become increasingly used to assess distributions of species, we recommend systematic assessments of the quality of habitat in addition to the classical binary classification of habitat. We devised a method to assess occurrence probability, captured by a climatic suitability index, through which we could determine variations in the quality of potential habitat. This relative risk assessment circumvents the use of an arbitrary suitability threshold. We illustrated our method with 2 case studies on invasive ant species. We estimated invasion potential of the destroyer ant (Monomorium destructor) and the European fire ant (Myrmica rubra) on a global scale currently and by 2080 with climate change. We found that 21.1% of the world's landmass currently has a suitable climate for the destroyer ant and 16% has a suitable climate for European fire ant. Our climatic suitability index showed that both ant species would benefit from climate change, but in different ways. The size of the potential distribution increased by 35.8% for the destroyer ant. Meanwhile, the total area of potential distribution remained the same for the European fire ant (>0.05%), but the level of climatic suitability within this range increased greatly and led to an improvement in habitat quality (i.e., of invasive species' establishment likelihood). Either through quantity or quality of suitable areas, both invasive ant species are likely to increase the extent of their invasion in the future, following global climate change. Our results show that species may increase their range if either more areas become suitable or if the available areas present improved suitability. Studies in which an arbitrary suitability threshold was used may overlook changes in area quality within climatically suitable areas and as a result reach incorrect predictions. Incremento de la Cantidad y Calidad de Áreas Idóneas para Especies Invasoras a Medida que Cambia el Clima.

  2. Comparison of two down-scaling methods for climate study and climate change on the mountain areas in France

    International Nuclear Information System (INIS)

    Piazza, Marie; Page, Christian; Sanchez-Gomez, Emilia; Terray, Laurent; Deque, Michel

    2013-01-01

    Mountain regions are highly vulnerable to climate change and are likely to be among the areas most impacted by global warming. But climate projections for the end of the 21. century are developed with general circulation models of climate, which do not present a sufficient horizontal resolution to accurately evaluate the impacts of warming on these regions. Several techniques are then used to perform a spatial down-scaling (on the order of 10 km). There are two categories of down-scaling methods: dynamical methods that require significant computational resources for the achievement of regional climate simulations at high resolution, and statistical methods that require few resources but an observation dataset over a long period and of good quality. In this study, climate simulations of the global atmospheric model ARPEGE projections over France are down-scaled according to a dynamical method, performed with the ALADIN-Climate regional model, and a statistical method performed with the software DSClim developed at CERFACS. The two down-scaling methods are presented and the results on the climate of the French mountains are evaluated for the current climate. Both methods give similar results for average snowfall. However extreme events of total precipitation (droughts, intense precipitation events) are largely underestimated by the statistical method. Then, the results of both methods are compared for two future climate projections, according to the greenhouse gas emissions scenario A1B of IPCC. The two methods agree on fewer frost days, a significant decrease in the amounts of solid precipitation and an average increase in the percentage of dry days of more than 10%. The results obtained on Corsica are more heterogeneous but they are questionable because the reduced spatial domain is probably not very relevant regarding statistical sampling. (authors)

  3. Global warming and South Indian monsoon rainfall-lessons from the Mid-Miocene.

    Science.gov (United States)

    Reuter, Markus; Kern, Andrea K; Harzhauser, Mathias; Kroh, Andreas; Piller, Werner E

    2013-04-01

    Precipitation over India is driven by the Indian monsoon. Although changes in this atmospheric circulation are caused by the differential seasonal diabatic heating of Asia and the Indo-Pacific Ocean, it is so far unknown how global warming influences the monsoon rainfalls regionally. Herein, we present a Miocene pollen flora as the first direct proxy for monsoon over southern India during the Middle Miocene Climate Optimum. To identify climatic key parameters, such as mean annual temperature, warmest month temperature, coldest month temperature, mean annual precipitation, mean precipitation during the driest month, mean precipitation during the wettest month and mean precipitation during the warmest month the Coexistence Approach is applied. Irrespective of a ~ 3-4 °C higher global temperature during the Middle Miocene Climate Optimum, the results indicate a modern-like monsoonal precipitation pattern contrasting marine proxies which point to a strong decline of Indian monsoon in the Himalaya at this time. Therefore, the strength of monsoon rainfall in tropical India appears neither to be related to global warming nor to be linked with the atmospheric conditions over the Tibetan Plateau. For the future it implies that increased global warming does not necessarily entail changes in the South Indian monsoon rainfall.

  4. Indian monsoon variability on millennial-orbital timescales.

    Science.gov (United States)

    Kathayat, Gayatri; Cheng, Hai; Sinha, Ashish; Spötl, Christoph; Edwards, R Lawrence; Zhang, Haiwei; Li, Xianglei; Yi, Liang; Ning, Youfeng; Cai, Yanjun; Lui, Weiguo Lui; Breitenbach, Sebastian F M

    2016-04-13

    The Indian summer monsoon (ISM) monsoon is critical to billions of people living in the region. Yet, significant debates remain on primary ISM drivers on millennial-orbital timescales. Here, we use speleothem oxygen isotope (δ(18)O) data from Bittoo cave, Northern India to reconstruct ISM variability over the past 280,000 years. We find strong coherence between North Indian and Chinese speleothem δ(18)O records from the East Asian monsoon domain, suggesting that both Asian monsoon subsystems exhibit a coupled response to changes in Northern Hemisphere summer insolation (NHSI) without significant temporal lags, supporting the view that the tropical-subtropical monsoon variability is driven directly by precession-induced changes in NHSI. Comparisons of the North Indian record with both Antarctic ice core and sea-surface temperature records from the southern Indian Ocean over the last glacial period do not suggest a dominant role of Southern Hemisphere climate processes in regulating the ISM variability on millennial-orbital timescales.

  5. THE EFFECTS OF CLIMATIC VARIABLES AND CROP AREA ON MAIZE YIELD AND VARIABILITY IN GHANA

    Directory of Open Access Journals (Sweden)

    Henry De-Graft Acquah

    2012-10-01

    Full Text Available Climate change tends to have negative effects on crop yield through its influence on crop production. Understanding the relationship between climatic variables and crop area on the mean and variance of crop yield will facilitate development of appropriate policies to cope with climate change. This paper examines the effects of climatic variables and crop area on the mean and variance of maize yield in Ghana. The Just and Pope stochastic production function using the Cobb-Douglas functional form was employed. The results show that average maize yield is positively related to crop area and negatively related to rainfall and temperature. Furthermore, increase in crop area and temperature will enlarge maize yield variability while rainfall increase will decrease the variability in maize yield.

  6. Changing Climate, Challenging Choices: Identifying and Evaluating Climate Change Adaptation Options for Protected Areas Management in Ontario, Canada

    Science.gov (United States)

    Lemieux, Christopher J.; Scott, Daniel J.

    2011-10-01

    Climate change will pose increasingly significant challenges to managers of parks and other forms of protected areas around the world. Over the past two decades, numerous scientific publications have identified potential adaptations, but their suitability from legal, policy, financial, internal capacity, and other management perspectives has not been evaluated for any protected area agency or organization. In this study, a panel of protected area experts applied a Policy Delphi methodology to identify and evaluate climate change adaptation options across the primary management areas of a protected area agency in Canada. The panel identified and evaluated one hundred and sixty five (165) adaptation options for their perceived desirability and feasibility. While the results revealed a high level of agreement with respect to the desirability of adaptation options and a moderate level of capacity pertaining to policy formulation and management direction, a perception of low capacity for implementation in most other program areas was identified. A separate panel of senior park agency decision-makers used a multiple criterion decision-facilitation matrix to further evaluate the institutional feasibility of the 56 most desirable adaptation options identified by the initial expert panel and to prioritize them for consideration in a climate change action plan. Critically, only two of the 56 adaptation options evaluated by senior decision-makers were deemed definitely implementable, due largely to fiscal and internal capacity limitations. These challenges are common to protected area agencies in developed countries and pervade those in developing countries, revealing that limited adaptive capacity represents a substantive barrier to biodiversity conservation and other protected area management objectives in an era of rapid climate change.

  7. Winter/Summer Monsoon Experiment

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Winter/Summer Monsoon Experiment (MONEX) was conducted during the First Global GARP (Global Atmospheric Research Program) Experiment (FGGE). An international...

  8. Sustainability Challenges from Climate Change and Air Conditioning Use in Urban Areas

    OpenAIRE

    Lundgren, Karin; Kjellström, Tord

    2013-01-01

    Global climate change increases heat loads in urban areas causing health and productivity risks for millions of people. Inhabitants in tropical and subtropical urban areas are at especial risk due to high population density, already high temperatures, and temperature increases due to climate change. Air conditioning is growing rapidly, especially in South and South-East Asia due to income growth and the need to protect from high heat exposures. Studies have linked increased total hourly elect...

  9. Projected impacts of climate change on a continent-wide protected area network

    DEFF Research Database (Denmark)

    Hole, David G; Willis, Stephen G; Pain, Deborah J

    2009-01-01

    Despite widespread concern, the continuing effectiveness of networks of protected areas under projected 21st century climate change is uncertain. Shifts in species' distributions could mean these resources will cease to afford protection to those species for which they were originally established...... species). Persistence of suitable climate space across the network as a whole, however, is notably high, with 88-92% of priority species retaining suitable climate space in >or= 1 IBA(s) in which they are currently found. Only 7-8 priority species lose climatic representation from the network. Hence......, despite the likelihood of significant community disruption, we demonstrate that rigorously defined networks of protected areas can play a key role in mitigating the worst impacts of climate change on biodiversity....

  10. Sustainability Challenges from Climate Change and Air Conditioning Use in Urban Areas

    Directory of Open Access Journals (Sweden)

    Karin Lundgren

    2013-07-01

    Full Text Available Global climate change increases heat loads in urban areas causing health and productivity risks for millions of people. Inhabitants in tropical and subtropical urban areas are at especial risk due to high population density, already high temperatures, and temperature increases due to climate change. Air conditioning is growing rapidly, especially in South and South-East Asia due to income growth and the need to protect from high heat exposures. Studies have linked increased total hourly electricity use to outdoor temperatures and humidity; modeled future predictions when facing additional heat due to climate change, related air conditioning with increased street level heat and estimated future air conditioning use in major urban areas. However, global and localized studies linking climate variables with air conditioning alone are lacking. More research and detailed data is needed looking at the effects of increasing air conditioning use, electricity consumption, climate change and interactions with the urban heat island effect. Climate change mitigation, for example using renewable energy sources, particularly photovoltaic electricity generation, to power air conditioning, and other sustainable methods to reduce heat exposure are needed to make future urban areas more climate resilient.

  11. Monsoon Rainfall and Landslides in Nepal

    Science.gov (United States)

    Dahal, R. K.; Hasegawa, S.; Bhandary, N. P.; Yatabe, R.

    2009-12-01

    A large number of human settlements on the Nepal Himalayas are situated either on old landslide mass or on landslide-prone areas. As a result, a great number of people are affected by large- and small-scale landslides all over the Himalayas especially during monsoon periods. In Nepal, only in the half monsoon period (June 10 to August 15), 70, 50 and 68 people were killed from landslides in 2007, 2008 and 2009, respectively. In this context, this paper highlights monsoon rainfall and their implications in the Nepal Himalaya. In Nepal, monsoon is major source of rainfall in summer and approximately 80% of the annual total rainfall occurs from June to September. The measured values of mean annual precipitation in Nepal range from a low of approximately 250 mm at area north of the Himalaya to many areas exceeding 6,000 mm. The mean annual rainfall varying between 1500 mm and 2500 mm predominate over most of the country. In Nepal, the daily distribution of precipitation during rainy season is also uneven. Sometime 10% of the total annual precipitation can occur in a single day. Similarly, 50% total annual rainfall also can occur within 10 days of monsoon. This type of uneven distribution plays an important role in triggering many landslides in Nepal. When spatial distribution of landslides was evaluated from record of more than 650 landslides, it is found that more landslides events were concentrated at central Nepal in the area of high mean annual rainfall. When monsoon rainfall and landslide relationship was taken into consideration, it was noticed that a considerable number of landslides were triggered in the Himalaya by continuous rainfall of 3 to 90 days. It has been noticed that continuous rainfall of few days (5 days or 7 days or 10 days) are usually responsible for landsliding in the Nepal Himalaya. Monsoon rains usually fall with interruptions of 2-3 days and are generally characterized by low intensity and long duration. Thus, there is a strong role of

  12. Predicting onset and withdrawal of Indian Summer Monsoon in 2016: results of Tipping elements approach

    Science.gov (United States)

    Surovyatkina, Elena; Stolbova, Veronika; Kurths, Jurgen

    2017-04-01

    started to decrease, and after two days meteorological stations reported 'No rain' in the EG and also in areas located across the subcontinent in the direction from the North Pakistan to the Bay of Bengal. Hence, the date of monsoon withdrawal - October 10-th, predicted 70 days in advance, lies within our prediction interval. Our results show that our method allows predicting a future monsoon, and not only retrospectively or hindcast. In 2016 we predicted of the onset and withdrawal dates of the Southwest monsoon over the Eastern Ghats region in Central India for 40 and 70 days in advance respectively. Our general framework for predicting spatial-temporal critical transitions is applicable for systems of different nature. It allows predicting future from observational data only, when the model of a transition does not exist yet. [1] Stolbova, V., E. Surovyatkina, B. Bookhagen, and J. Kurths (2016): Tipping elements of the Indian monsoon: Prediction of onset and withdrawal. Geophys. Res. Lett., 43, 1-9. [2]https://www.pik-potsdam.de/news/press-releases/indian-monsoon-novel-approach-allows-early-forecasting?set_language=en [3] https://www.pik-potsdam.de/kontakt/pressebuero/fotos/monsoon-withdrawal/view

  13. Circumglobal wave train and the summer monsoon over northwestern India and Pakistan: the explicit role of the surface heat low

    Energy Technology Data Exchange (ETDEWEB)

    Saeed, Sajjad [Max Planck Institute for Meteorology, Hamburg (Germany); International Max Planck Research School on Earth System Modeling, Hamburg (Germany); Pakistan Meteorological Department, Islamabad (Pakistan); Mueller, Wolfgang A.; Hagemann, Stefan; Jacob, Daniela [Max Planck Institute for Meteorology, Hamburg (Germany)

    2011-09-15

    This study examines the influence of the mid-latitude circulation on the surface heat low (HL) and associated monsoon rainfall over northwestern India and Pakistan using the ERA40 data and high resolution (T106L31) climate model ECHAM5 simulation. Special emphasis is given to the surface HL which forms over Pakistan and adjoining areas of India, Iran and Afghanistan during the summer season. A heat low index (HLI) is defined to depict the surface HL. The HLI displays significant correlations with the upper level mid-latitude circulation over western central Asia and low level monsoon circulation over Arabian Sea and acts as a bridge connecting the mid-latitude wave train to the Indian summer monsoon. A time-lagged singular value decomposition analysis reveals that the eastward propagation of the mid-latitude circumglobal wave train (CGT) influences the surface pressure anomalies over the Indian domain. The largest low (negative) pressure anomalies over the western parts of the HL region (i.e., Iran and Afghanistan) occur in conjunction with the upper level anomalous high that develops over western-central Asia during the positive phase of the CGT. The composite analysis also reveals a significant increase in the low pressure anomalies over Iran and Afghanistan during the positive phase of CGT. The westward increasing low pressure anomalies with its north-south orientation provokes enormous north-south pressure gradient (lower pressure over land than over sea). This in turn enables the moist southerly flow from the Arabian Sea to penetrate farther northward over northwestern India and Pakistan. A monsoon trough like conditions develops over northwestern India and Pakistan where the moist southwesterly flow from the Arabian Sea and the Persian Gulf converge. The convergence in association with the orographic uplifting expedites convection and associated precipitation over northwestern India and Pakistan. The high resolution climate model ECHAM5 simulation also

  14. Comparative Study of Monsoon Rainfall Variability over India and the Odisha State

    Directory of Open Access Journals (Sweden)

    K C Gouda

    2017-10-01

    Full Text Available Indian summer monsoon (ISM plays an important role in the weather and climate system over India. The rainfall during monsoon season controls many sectors from agriculture, food, energy, and water, to the management of disasters. Being a coastal province on the eastern side of India, Odisha is one of the most important states affected by the monsoon rainfall and associated hydro-meteorological systems. The variability of monsoon rainfall is highly unpredictable at multiple scales both in space and time. In this study, the monsoon variability over the state of Odisha is studied using the daily gridded rainfall data from India Meteorological Department (IMD. A comparative analysis of the behaviour of monsoon rainfall at a larger scale (India, regional scale (Odisha, and sub-regional scale (zones of Odisha is carried out in terms of the seasonal cycle of monsoon rainfall and its interannual variability. It is seen that there is no synchronization in the seasonal monsoon category (normal/excess/deficit when analysed over large (India and regional (Odisha scales. The impact of El Niño, La Niña, and the Indian Ocean Dipole (IOD on the monsoon rainfall at both scales (large scale and regional scale is analysed and compared. The results show that the impact is much more for rainfall over India, but it has no such relation with the rainfall over Odisha. It is also observed that there is a positive (negative relation of the IOD with the seasonal monsoon rainfall variability over Odisha (India. The correlation between the IAV of monsoon rainfall between the large scale and regional scale was found to be 0.46 with a phase synchronization of 63%. IAV on a sub-regional scale is also presented.

  15. International and European law on protected areas and climate change: need for adaptation or implementation?

    Science.gov (United States)

    Cliquet, A

    2014-10-01

    The protection and management of protected areas must be adapted to the effects of climate change. An important question is if the law on protected areas is capable of dealing with the required changes. In general, both international nature conventions and European Union nature conservation law do not contain any specific provisions on climate change and protected areas. Attention has been paid to this link in non-binding decisions and policy documents. In order to adapt the law to increased dynamics from climate change, more flexibility is needed. This flexibility should not be understood as "legal" flexibility, in the sense of the weakening nature conservation provisions. Scientific uncertainties on the effects of climate change might conflict with the need for legal certainties. In order to adapt to the effects of climate change, the two crucial elements are the strengthening of core protected areas and connectivity between the core areas. At the international level, both elements can be found in non-binding documents. International law enables the required adaptation; however, it often lacks concrete obligations. A stronger legal framework can be found at the level of the European Union. The Birds and Habitats Directives contain sufficient tools to deal with the effects of climate change. The Directives have been insufficiently implemented so far. Especially the central goals of reaching a favorable conservation status and connectivity measures need to be addressed much more in the future.

  16. Assessing climate change-robustness of protected area management plans-The case of Germany.

    Science.gov (United States)

    Geyer, Juliane; Kreft, Stefan; Jeltsch, Florian; Ibisch, Pierre L

    2017-01-01

    Protected areas are arguably the most important instrument of biodiversity conservation. To keep them fit under climate change, their management needs to be adapted to address related direct and indirect changes. In our study we focus on the adaptation of conservation management planning, evaluating management plans of 60 protected areas throughout Germany with regard to their climate change-robustness. First, climate change-robust conservation management was defined using 11 principles and 44 criteria, which followed an approach similar to sustainability standards. We then evaluated the performance of individual management plans concerning the climate change-robustness framework. We found that climate change-robustness of protected areas hardly exceeded 50 percent of the potential performance, with most plans ranking in the lower quarter. Most Natura 2000 protected areas, established under conservation legislation of the European Union, belong to the sites with especially poor performance, with lower values in smaller areas. In general, the individual principles showed very different rates of accordance with our principles, but similarly low intensity. Principles with generally higher performance values included holistic knowledge management, public accountability and acceptance as well as systemic and strategic coherence. Deficiencies were connected to dealing with the future and uncertainty. Lastly, we recommended the presented principles and criteria as essential guideposts that can be used as a checklist for working towards more climate change-robust planning.

  17. Assessing climate change-robustness of protected area management plans—The case of Germany

    Science.gov (United States)

    Geyer, Juliane; Kreft, Stefan; Jeltsch, Florian; Ibisch, Pierre L.

    2017-01-01

    Protected areas are arguably the most important instrument of biodiversity conservation. To keep them fit under climate change, their management needs to be adapted to address related direct and indirect changes. In our study we focus on the adaptation of conservation management planning, evaluating management plans of 60 protected areas throughout Germany with regard to their climate change-robustness. First, climate change-robust conservation management was defined using 11 principles and 44 criteria, which followed an approach similar to sustainability standards. We then evaluated the performance of individual management plans concerning the climate change-robustness framework. We found that climate change-robustness of protected areas hardly exceeded 50 percent of the potential performance, with most plans ranking in the lower quarter. Most Natura 2000 protected areas, established under conservation legislation of the European Union, belong to the sites with especially poor performance, with lower values in smaller areas. In general, the individual principles showed very different rates of accordance with our principles, but similarly low intensity. Principles with generally higher performance values included holistic knowledge management, public accountability and acceptance as well as systemic and strategic coherence. Deficiencies were connected to dealing with the future and uncertainty. Lastly, we recommended the presented principles and criteria as essential guideposts that can be used as a checklist for working towards more climate change-robust planning. PMID:28982187

  18. What drives the global summer monsoon over the past millennium?

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jian [Chinese Academy of Sciences, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Nanjing (China); Wang, Bin [University of Hawaii at Manoa, Department of Meteorology, Honolulu, HI (United States); University of Hawaii at Manoa, International Pacific Research Center, Honolulu, HI (United States); Yim, So-Young; Lee, June-Yi [University of Hawaii at Manoa, International Pacific Research Center, Honolulu, HI (United States); Jhun, Jong-Ghap [Seoul National University, School of Earth and Environmental Sciences/Research Institute of Oceanography, Seoul (Korea, Republic of); Ha, Kyung-Ja [Pusan National University, Division of Earth Environmental System, Busan (Korea, Republic of)

    2012-09-15

    The global summer monsoon precipitation (GSMP) provides a fundamental measure for changes in the annual cycle of the climate system and hydroclimate. We investigate mechanisms governing decadal-centennial variations of the GSMP over the past millennium with a coupled climate model's (ECHO-G) simulation forced by solar-volcanic (SV) radiative forcing and greenhouse gases (GHG) forcing. We show that the leading mode of GSMP is a forced response to external forcing on centennial time scale with a globally uniform change of precipitation across all monsoon regions, whereas the second mode represents internal variability on multi-decadal time scale with regional characteristics. The total amount of GSMP varies in phase with the global mean temperature, indicating that global warming is accompanied by amplification of the annual cycle of the climate system. The northern hemisphere summer monsoon precipitation (NHSMP) responds to GHG forcing more sensitively, while the southern hemisphere summer monsoon precipitation (SHSMP) responds to the SV radiative forcing more sensitively. The NHSMP is enhanced by increased NH land-ocean thermal contrast and NH-minus-SH thermal contrast. On the other hand, the SHSMP is strengthened by enhanced SH subtropical highs and the east-west mass contrast between Southeast Pacific and tropical Indian Ocean. The strength of the GSMP is determined by the factors controlling both the NHSMP and SHSMP. Intensification of GSMP is associated with (a) increased global land-ocean thermal contrast, (b) reinforced east-west mass contrast between Southeast Pacific and tropical Indian Ocean, and (c) enhanced circumglobal SH subtropical highs. The physical mechanisms revealed here will add understanding of future change of the global monsoon. (orig.)

  19. Late Holocene anti-phase change in the East Asian summer and winter monsoons

    Science.gov (United States)

    Kang, Shugang; Wang, Xulong; Roberts, Helen M.; Duller, Geoff A. T.; Cheng, Peng; Lu, Yanchou; An, Zhisheng

    2018-05-01

    Changes in East Asian summer and winter monsoon intensity have played a pivotal role in the prosperity and decline of society in the past, and will be important for future climate scenarios. However, the phasing of changes in the intensity of East Asian summer and winter monsoons on millennial and centennial timescales during the Holocene is unclear, limiting our ability to understand the factors driving past and future changes in the monsoon system. Here, we present a high resolution (up to multidecadal) loess record for the last 3.3 ka from the southern Chinese Loess Plateau that clearly demonstrates the relationship between changes in the intensity of the East Asian summer and winter monsoons, particularly at multicentennial scales. At multimillennial scales, the East Asian summer monsoon shows a steady weakening, while the East Asian winter monsoon intensifies continuously. At multicentennial scales, a prominent ∼700-800 yr cycle in the East Asian summer and winter monsoon intensity is observed, and here too the two monsoons are anti-phase. We conclude that multimillennial changes are driven by Northern Hemisphere summer insolation, while multicentennial changes can be correlated with solar activity and changing strength of the Atlantic meridional overturning circulation.

  20. Benchmark analysis of forecasted seasonal temperature over different climatic areas

    Science.gov (United States)

    Giunta, G.; Salerno, R.; Ceppi, A.; Ercolani, G.; Mancini, M.

    2015-12-01

    From a long-term perspective, an improvement of seasonal forecasting, which is often exclusively based on climatology, could provide a new capability for the management of energy resources in a time scale of just a few months. This paper regards a benchmark analysis in relation to long-term temperature forecasts over Italy in the year 2010, comparing the eni-kassandra meteo forecast (e-kmf®) model, the Climate Forecast System-National Centers for Environmental Prediction (CFS-NCEP) model, and the climatological reference (based on 25-year data) with observations. Statistical indexes are used to understand the reliability of the prediction of 2-m monthly air temperatures with a perspective of 12 weeks ahead. The results show how the best performance is achieved by the e-kmf® system which improves the reliability for long-term forecasts compared to climatology and the CFS-NCEP model. By using the reliable high-performance forecast system, it is possible to optimize the natural gas portfolio and management operations, thereby obtaining a competitive advantage in the European energy market.

  1. Reforecasting the 1972-73 ENSO Event and the Monsoon Drought Over India

    Science.gov (United States)

    Shukla, J.; Huang, B.; Shin, C. S.

    2016-12-01

    This paper presents the results of reforcasting the 1972-73 ENSO event and the Indian summer monsoon drought using the National Centers for Environmental Prediction (NCEP) Climate Forecast System, version 2 (CFSv2), initialized with the Eu­ropean Centre for Medium-Range Weather Forecasts (ECMWF) global ocean reanalysis version 4, and observation-based land and atmosphere reanalyses. The results of this paper demonstrate that if the modern day climate models were available during the 1970's, even with the limited observations at that time, it should have been possible to predict the 1972-73 ENSO event and the associated monsoon drought. These results further suggest the necessity of continuing to develop realistic models of the climate system for accurate and reliable seasonal predictions. This paper also presents a comparison of the 1972-73 El Niño reforecast with the 1997-98 case. As the strongest event during 1958-78, the 1972-73 El Niño is distinguished from the 1997-98 one by its early termination. Initialized in the spring season, the forecast system predicted the onset and development of both events reasonably well, although the reforecasts underestimate the ENSO peaking magnitudes. On the other hand, the reforecasts initialized in spring and fall of 1972 persistently predicted lingering wind and SST anomalies in the eastern equatorial Pacific during the spring of 1973. Initialized in fall of 1997, the reforecast also grossly overestimates the peaking westerly wind and warm SST anomalies in the 1997-98 El Niño.In 1972-73, both the Eastern Pacific SST anomalies (for example Nino 3 Index) and the summer monsoon drought over India and the adjoining areas were predicted remarkably well. In contrast, the Eastern Pacific SST anomalies for the 1997-98 event were predicted well, but the normal summer monsoon rainfall over India of 1997 was not predicted by the model. This case study of the 1972-73 event is part of a larger, comprehensive reforecast project

  2. Changes in the in-phase relationship between the Indian and subsequent Australian summer monsoons during the past five decades

    Directory of Open Access Journals (Sweden)

    J.-Y. Yu

    2007-10-01

    Full Text Available This study examines the decadal changes in the in-phase relationship between Indian summer monsoon and the subsequent Australian summer monsoon using observational data from 1950–2005. The in-phase relationship is the tendency for a strong Indian summer monsoon to be followed by a strong Australian summer monsoon and vice versa. It is found that the in-phase relationship was weak during the late 1950s and early 1960s, strengthened to a maximum in the early 1970s just before the 1976/77 Pacific climate shift, then declined until the late 1990s. Pacific SST anomalies are noticed to have strong persistence from boreal to austral summer, providing the memory to connect the Indian and subsequent Australian summer monsoon. The simultaneous correlation between the Pacific SST anomalies and the Indian summer monsoon is always strong. It is the weakening and strengthening of the simultaneous correlation between the Australian summer monsoon and the Pacific SST anomalies that contributes to the decadal variations of the in-phase monsoon relation. This study suggests that the interaction between the Australian monsoon and the Pacific Ocean is crucial to tropical climate variability and has experienced significant changes over the past five decades.

  3. Pleistocene Indian Monsoon Rainfall Variability

    Science.gov (United States)

    Yirgaw, D. G.; Hathorne, E. C.; Giosan, L.; Collett, T. S.; Sijingeo, A. V.; Nath, B. N.; Frank, M.

    2014-12-01

    The past variability of the Indian Monsoon is mostly known from records of wind strength over the Arabian Sea. Here we investigate proxies for fresh water input and runoff in a region of strong monsoon precipitation that is a major moisture source for the east Asian Monsoon. A sediment core obtained by the IODP vessel JOIDES Resolution and a gravity core from the Alcock Seamount complex in the Andaman Sea are used to examine the past monsoon variability on the Indian sub-continent and directly over the ocean. The current dataset covers the last glacial and deglacial but will eventually provide a Pleistocene record. We utilise the ecological habitats of G. sacculifer and N. dutertrei to investigate the freshwater-induced stratification with paired Mg/Ca and δ18O analyses to estimate seawater δ18O (δ18Osw). During the last 60 kyrs, Ba/Ca ratios and δ18Osw values generally agree well between the two cores and suggest the weakest surface runoff and monsoon during the LGM and strongest monsoon during the Holocene. The difference in δ18O between the species, interpreted as a proxy for upper ocean stratification, implies stratification developed around 37 ka and remained relatively constant during the LGM, deglacial and Holocene. To investigate monsoon variability for intervals in the past, single shell Mg/Ca and δ18O analyses have been conducted. Mg/Ca ratios from individual shells of N. dutertrei suggest relatively small changes in temperature. However, individual N. dutertrei δ18O differ greatly between the mid-Holocene and samples from the LGM and a nearby core top. The mid-Holocene individuals have a greater range and large skew towards negative values indicating greater fresh water influence.

  4. The Indian Monsoon

    Indian Academy of Sciences (India)

    2006-06-23

    Jun 23, 2006 ... of the climate over our region, its seasonal variation and impact on agriculture have .... tuned to this rhythmic variation of their environment. ... Analysis of the daily rainfall data available at India Meteorologi- cal Department ...

  5. Potential modulations of pre-monsoon aerosols during El Niño: impact on Indian summer monsoon

    Science.gov (United States)

    Fadnavis, S.; Roy, Chaitri; Sabin, T. P.; Ayantika, D. C.; Ashok, K.

    2017-10-01

    The potential role of aerosol loading on the Indian summer monsoon rainfall during the El Niño years are examined using satellite-derived observations and a state of the art fully interactive aerosol-chemistry-climate model. The Aerosol Index (AI) from TOMS (1978-2005) and Aerosol Optical Depth (AOD) from MISR spectroradiometer (2000-2010) indicate a higher-than-normal aerosol loading over the Indo-Gangetic plain (IGP) during the pre-monsoon season with a concurrent El Niño. Sensitivity experiments using ECHAM5-HAMMOZ climate model suggests that this enhanced loading of pre-monsoon absorbing aerosols over the Indo-Gangetic plain can reduce the drought during El Niño years by invoking the `Elevated-Heat-Pump' mechanism through an anomalous aerosol-induced warm core in the atmospheric column. This anomalous heating upshot the relative strengthening of the cross-equatorial moisture inflow associated with the monsoon and eventually reduces the severity of drought during El Niño years. The findings are subject to the usual limitations such as the uncertainties in observations, and limited number of El Niño years (during the study period).

  6. Natural areas as a basis for assessing ecosystem vulnerability to climate change

    Science.gov (United States)

    Margaret H. Massie; Todd M. Wilson; Anita T. Morzillo; Emilie B. Henderson

    2016-01-01

    There are more than 580 natural areas in Oregon and Washington managed by 20 federal, state, local, and private agencies and organizations. This natural areas network is unparalleled in its representation of the diverse ecosystems found in the Pacific Northwest, and could prove useful for monitoring long-term ecological responses to climate change. Our objectives were...

  7. Risk to a Changing Climate in the Mexico City Metropolitan Area

    Science.gov (United States)

    Vargas, N. D.

    2016-12-01

    The issue of climate change has dominated the atmospheric sciences agenda in recent decades. The concern about an increase in climate related disasters, mainly in large population centers, has led to ask whether they are mainly due to changes in climate or in vulnerability.The Mexico City Metropolitan Area (MCMA) is an example of megalopolis under high climate risk, where floods, landslides, health problems, high air pollution events, socioeconomic droughts are becoming important environmental and social problems. As urbanization spreads and population increases exposure to natural hazards increases, and so the magnitude of risk to a changing climate and the negative impacts. Since the late nineteenth century, in the MCMA an average maximum temperature could be around 22°C, whereas today it is about 24.5ºC. That is, the increase in the average temperature in Mexico City is around 3°C in a hundred years. But there are areas where an increase in the average temperature is similar in only thirty years. The heating rate of the city can vary depending on the change in land use. Areas that conserve forested regions in the process of urbanization tend to warm less than areas where the transformation into concrete and cement is almost complete. Thus, the climate of the MCMA shows important changes mainly in relation to land use changes. Global warming and natural climate variability were also analyzed as possible forcing factors of the observed warming by comparing low frequency variations in local temperature and indices for natural forcing. The hydrological cycle of the MCMA has also changed with urbanization. The "bubble of hot air" over the urban area has more capacity to hold moisture now than before the UHI. However, the increased risk to floods, heat or drought appears to be related not only to more frequent intense climatic hazards induced by the urbanization effect. This process also induces increased vulnerability to a changing climate. The establishment of

  8. Effects of increased CO{sub 2} levels on monsoons

    Energy Technology Data Exchange (ETDEWEB)

    Cherchi, Annalisa; Masina, Simona; Navarra, Antonio [Centro Euro-Mediterraneo per i Cambiamenti Climatici and Istituto Nazionale di Geofisica e Vulcanologia, Bologna (Italy); Alessandri, Andrea [Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna (Italy)

    2011-07-15

    Increased atmospheric carbon dioxide concentration provided warmer atmospheric temperature and higher atmospheric water vapor content, but not necessarily more precipitation. A set of experiments performed with a state-of-the-art coupled general circulation model forced with increased atmospheric CO{sub 2} concentration (2, 4 and 16 times the present-day mean value) were analyzed and compared with a control experiment to evaluate the effect of increased CO{sub 2} levels on monsoons. Generally, the monsoon precipitation responses to CO{sub 2} forcing are largest if extreme concentrations of carbon dioxide are used, but they are not necessarily proportional to the forcing applied. In fact, despite a common response in terms of an atmospheric water vapor increase to the atmospheric warming, two out of the six monsoons studied simulate less or equal summer mean precipitation in the 16 x CO{sub 2} experiment compared to the intermediate sensitivity experiments. The precipitation differences between CO{sub 2} sensitivity experiments and CTRL have been investigated specifying the contribution of thermodynamic and purely dynamic processes. As a general rule, the differences depending on the atmospheric moisture content changes (thermodynamic component) are large and positive, and they tend to be damped by the dynamic component associated with the changes in the vertical velocity. However, differences are observed among monsoons in terms of the role played by other terms (like moisture advection and evaporation) in shaping the precipitation changes in warmer climates. The precipitation increase, even if weak, occurs despite a weakening of the mean circulation in the monsoon regions (''precipitation-wind paradox''). In particular, the tropical east-west Walker circulation is reduced, as found from velocity potential analysis. The meridional component of the monsoon circulation is changed as well, with larger (smaller) meridional (vertical) scales. (orig.)

  9. Managing for climate change on protected areas: An adaptive management decision making framework.

    Science.gov (United States)

    Tanner-McAllister, Sherri L; Rhodes, Jonathan; Hockings, Marc

    2017-12-15

    Current protected area management is becoming more challenging with advancing climate change and current park management techniques may not be adequate to adapt for effective management into the future. The framework presented here provides an adaptive management decision making process to assist protected area managers with adapting on-park management to climate change. The framework sets out a 4 step process. One, a good understanding of the park's context within climate change. Secondly, a thorough understanding of the park management systems including governance, planning and management systems. Thirdly, a series of management options set out as an accept/prevent change style structure, including a systematic assessment of those options. The adaptive approaches are defined as acceptance of anthropogenic climate change impact and attempt to adapt to a new climatic environment or prevention of change and attempt to maintain current systems under new climatic variations. Last, implementation and monitoring of long term trends in response to ecological responses to management interventions and assessing management effectiveness. The framework addresses many issues currently with park management in dealing with climate change including the considerable amount of research focussing on 'off-reserve' strategies, and threats and stress focused in situ park management. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Climate variability and impacts on east African livestock herders: The Maasai of Ngorongoro Conservation Area, Tanzania

    OpenAIRE

    Galvin, K.A.; Thornton, P.K.; Boone, R.B.; Sunderland, J.

    2004-01-01

    Metadata only record East African pastoral adaptation and vulnerability to climate variability and climate change is assessed, using data from decision-making processes and ecological data of the Maasai of Ngorongoro Conservation Area as an example. The paper uses integrated modeling, linking PHEWS, a household model, to SAVANNA, an ecosystem model to look at the effects of drought and a series of wet years on the well-being of Maasai pastoralists. Model results suggest that the ecosystem ...

  11. New climate-proof cropping systems in dry areas of the Mediterranean region

    DEFF Research Database (Denmark)

    Jacobsen, Sven-Erik

    2014-01-01

    severe consequences of climate changes, under influence of multiple abiotic stresses. These stresses are becoming even more pronounced under changing climate, resulting in drier conditions, increasing temperatures and greater variability, causing desertification. This topic has been addressed in the EU...... FP7 project entitled 'Sustainable water use securing food production in dry areas of the Mediterranean region (SWUP-MED)' working on climate-proof cropping systems in Morocco, Syria, Turkey and southern Europe, collaborating with UK, Denmark and Australia. The results are valid for other parts...

  12. Identifying Effective Strategies for Climate Change Education: The Coastal Areas Climate Change Education (CACCE) Partnership Audiences and Activities

    Science.gov (United States)

    Ryan, J. G.; Feldman, A.; Muller-Karger, F. E.; Gilbes, F.; Stone, D.; Plank, L.; Reynolds, C. J.

    2011-12-01

    Many past educational initiatives focused on global climate change have foundered on public skepticism and disbelief. Some key reasons for these past failures can be drawn directly from recognized best practices in STEM education - specifically, the necessity to help learners connect new knowledge with their own experiences and perspectives, and the need to create linkages with issues or concerns that are both important for and relevant to the audiences to be educated. The Coastal Areas Climate Change Education (CACCE) partnership has sought to follow these tenets as guiding principles in identifying critical audiences and developing new strategies for educating the public living in the low-lying coastal areas of Florida and the Caribbean on the realities, risks, and adaptation and mitigation strategies for dealing with the regional impacts of global climate change. CACCE is currently focused on three key learner audiences: a) The formal education spectrum, targeting K-12 curricula through middle school marine science courses, and student and educator audiences through coursework and participatory research strategies engaging participants in a range of climate-related investigations. b) Informal science educators and outlets, in particular aquaria and nature centers, as an avenue toward K-12 teacher professional development as well as for public education. c) Regional planning, regulatory and business professionals focused on the built environment along the coasts, many of whom require continuing education to maintain licensing and/or other professional certifications. Our current activities are focused on bringing together an effective set of educational, public- and private-sector partners to target the varied needs of these audiences in Florida and the U.S. Caribbean, and tailoring an educational plan aimed at these stakeholder audiences that starts with the regionally and topically relevant impacts of climate change, and strategies for effective adaptation and

  13. Climate Change Impacts on Ecosystem Services in High Mountain Areas: A Literature Review

    Directory of Open Access Journals (Sweden)

    Ignacio Palomo

    2017-05-01

    Full Text Available High mountain areas are experiencing some of the earliest and greatest impacts of climate change. However, knowledge on how climate change impacts multiple ecosystem services that benefit different stakeholder groups remains scattered in the literature. This article presents a review of the literature on climate change impacts on ecosystem services benefiting local communities and tourists in high mountain areas. Results show a lack of studies focused on the global South, especially where there are tropical glaciers, which are likely to be the first to disappear. Climate change impacts can be classified as impacts on food and feed, water availability, natural hazards regulation, spirituality and cultural identity, aesthetics, and recreation. In turn, climate change impacts on infrastructure and accessibility also affect ecosystem services. Several of these impacts are a direct threat to the lives of mountain peoples, their livelihoods and their culture. Mountain tourism is experiencing abrupt changes too. The magnitude of impacts make it necessary to strengthen measures to adapt to climate change in high mountain areas.

  14. Circulation characteristics of a monsoon depression during ...

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    ciated with organized convective processes in a monsoon depression. The objective is to ..... the errors are large and the performance of the high-resolution ... Ramage C S 1971 Monsoon meteorology (London: Academic. Press) 45–46.

  15. On breaks of the Indian monsoon

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    quadrapole is a basic feature of weak spells of the intraseasonal variation over the Asia-west Pacific region. ... (Earth Planet. Sci.), 112 .... be useful to define the break monsoon (and active ... monsoon zone, different scientists have used the.

  16. Flood risk and climate change in the Rotterdam area, The Netherlands: Enhancing citizen's climate risk perceptions and prevention responses despite skepticism

    OpenAIRE

    de Boer, J.; Botzen, W.J.W.; Terpstra, T.

    2016-01-01

    Effective communication about climate change and related risks is complicated by the polarization between “climate alarmists” and “skeptics.” This paper provides insights for the design of climate risk communication strategies by examining how the interplay between climate change and flood risk communication affects citizens’ risk perceptions and responses. The study is situated in a delta area with substantial geographic variations in the occurrence and potential impact of flood risk, which ...

  17. Effect of increasing greenhouse gases on Indian monsoon rainfall as downscaled from the ECHAM coupled model

    International Nuclear Information System (INIS)

    Singh, S.V.; Storch, H.V.

    1994-01-01

    It is more or less accepted that the increasing anthropogenic gases will result in global warming through the greenhouse effect. The major influence of this will be felt in the form of ice melts and rising sea levels. The influence on regional climates like monsoons is not very clear. Since the monsoons arise due to surface heating, one would expect that global warming will lead to more vigorous monsoons. The expected change in a climate parameter can be studied by analyzing the historical data and then extrapolating in time. Alternatively, one can use the state-of-the-art coupled GCMs which are able to simulate the earth's climate with reasonable accuracy. Both methods have some limitations. The first method cannot adequately consider the nonlinearity, and the second method may not be efficient for regional scales. So that the projections can be trusted, the regional features should be well simulated. None of the current models are able to simulate the Indian monsoon satisfactorily. Therefore it is desirable to infer the expected change in monsoons from other large and near global scale features which are better simulated. This approach, which depends on the concurrent association between a large-scale modeled feature and a regional scale, is known as downscaling, after Storch et al., and is adopted here to project the Indian monsoon rainfall for the next 100 years from the ECHAM T21 coupled model

  18. [Responses of vegetation changes to climatic variations in Panxi area based on the MODIS multispectral data].

    Science.gov (United States)

    Shao, Huai-Yong; Wu, Jin-Hui; Liu, Meng; Yang, Wu-Nian

    2014-01-01

    It is an important research area to quantitatively studying the relationship between global climatic change and vegetation change based on the remote sensing technology. Panxi area is the ecological barrier of the upper reaches of the Yangtze River, and it is essential for the stability of the ecological environment of Sichuan as well as that of the whole China. The present article analyzes the vegetation change in 2001-2008 and the relationship between vegetation change and climatic variations of Panxi area, based on MODIS multispectral data and meteorological data. The results indicate that NDVI is positively correlated with temperature and precipitation. The precipitation is the major factor that affects the change of vegetation in the Panxi region and the trend of NDVI is similar with autumn precipitation; while at the same time the influence of climate has a one-month-time-lag.

  19. Future changes in Asian summer monsoon precipitation extremes as inferred from 20-km AGCM simulations

    Science.gov (United States)

    Lui, Yuk Sing; Tam, Chi-Yung; Lau, Ngar-Cheung

    2018-04-01

    This study examines the impacts of climate change on precipitation extremes in the Asian monsoon region during boreal summer, based on simulations from the 20-km Meteorological Research Institute atmospheric general circulation model. The model can capture the summertime monsoon rainfall, with characteristics similar to those from Tropical Rainfall Measuring Mission and Asian Precipitation-Highly-Resolved Observational Data Integration Towards Evaluation. By comparing the 2075-2099 with the present-day climate simulations, there is a robust increase of the mean rainfall in many locations due to a warmer climate. Over southeastern China, the Baiu rainband, Bay of Bengal and central India, extreme precipitation rates are also enhanced in the future, which can be inferred from increases of the 95th percentile of daily precipitation, the maximum accumulated precipitation in 5 consecutive days, the simple daily precipitation intensity index, and the scale parameter of the fitted gamma distribution. In these regions, with the exception of the Baiu rainband, most of these metrics give a fractional change of extreme rainfall per degree increase of the lower-tropospheric temperature of 5 to 8.5% K-1, roughly consistent with the Clausius-Clapeyron relation. However, over the Baiu area extreme precipitation change scales as 3.5% K-1 only. We have also stratified the rainfall data into those associated with tropical cyclones (TC) and those with other weather systems. The AGCM gives an increase of the accumulated TC rainfall over southeastern China, and a decrease in southern Japan in the future climate. The latter can be attributed to suppressed TC occurrence in southern Japan, whereas increased accumulated rainfall over southeastern China is due to more intense TC rain rate under global warming. Overall, non-TC weather systems are the main contributor to enhanced precipitation extremes in various locations. In the future, TC activities over southeastern China tend to further

  20. Non-linear regime shifts in Holocene Asian monsoon variability: potential impacts on cultural change and migratory patterns

    Science.gov (United States)

    Donges, J. F.; Donner, R. V.; Marwan, N.; Breitenbach, S. F. M.; Rehfeld, K.; Kurths, J.

    2015-05-01

    The Asian monsoon system is an important tipping element in Earth's climate with a large impact on human societies in the past and present. In light of the potentially severe impacts of present and future anthropogenic climate change on Asian hydrology, it is vital to understand the forcing mechanisms of past climatic regime shifts in the Asian monsoon domain. Here we use novel recurrence network analysis techniques for detecting episodes with pronounced non-linear changes in Holocene Asian monsoon dynamics recorded in speleothems from caves distributed throughout the major branches of the Asian monsoon system. A newly developed multi-proxy methodology explicitly considers dating uncertainties with the COPRA (COnstructing Proxy Records from Age models) approach and allows for detection of continental-scale regime shifts in the complexity of monsoon dynamics. Several epochs are characterised by non-linear regime shifts in Asian monsoon variability, including the periods around 8.5-7.9, 5.7-5.0, 4.1-3.7, and 3.0-2.4 ka BP. The timing of these regime shifts is consistent with known episodes of Holocene rapid climate change (RCC) and high-latitude Bond events. Additionally, we observe a previously rarely reported non-linear regime shift around 7.3 ka BP, a timing that matches the typical 1.0-1.5 ky return intervals of Bond events. A detailed review of previously suggested links between Holocene climatic changes in the Asian monsoon domain and the archaeological record indicates that, in addition to previously considered longer-term changes in mean monsoon intensity and other climatic parameters, regime shifts in monsoon complexity might have played an important role as drivers of migration, pronounced cultural changes, and the collapse of ancient human societies.

  1. The Indian Monsoon

    Indian Academy of Sciences (India)

    mathematical models of interactive populations. ... The most important facet of weather and climate in a tropical region such as ... dense cloud with considerable vertical extent,· in the form of. - . ... almost unhampered to the surface of the earth where it is ..... when effects of entrainment of the surrounding air due to viscos-.

  2. Meteorological results of monsoon-88 Expedition (pre-monsoon period)

    Digital Repository Service at National Institute of Oceanography (India)

    Sadhuram, Y.; Krishnamurthy, L.; Babu, M.T.

    Mean atmospheric circulation, moisture budget and net heat exchange were studied during a pre-monsoon period (18th March to 3rd May, 1988), making use of the data collected on board "Akademik Korolev" in the central equatorial and southern Arabian...

  3. Surface temperature pattern of the Indian Ocean before summer monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Gopinathan, C.K.; Rao, D.P.

    , suggests that the position of the warmer areas in the Bay of Bengal in May is an indicator of the subsequent summer rainfall over India. The statistical method adopted for the long range forcasting of the Indian summer monsoon gives very little...

  4. Disconnects Between Audiences, Resources, and Initiatives: Key Findings of the Coastal Areas Climate Change Education Partnership

    Science.gov (United States)

    Muller-Karger, F. E.; Ryan, J. G.; Feldman, A.; Gilbes, F.; Trotz, M.; McKayle, C.; Stone, D.; Plank, L.; Meisels, G.; Peterson, M.; Reynolds, C. J.

    2012-12-01

    The Coastal Areas Climate Change Education (CACCE) Partnership focused on defining a plan for effective education on climate change and its salient issues in coastal communities Florida and the US Caribbean territories. The approach included assessing perceptions and needs of stakeholders, evaluating the nature of available educational and information resources, and establishing a partnership that includes the public and professional organizations most relevant in planning and in addressing the resiliency of coastal communities. Information gathering activities included surveys among K-12 educators and students on climate change perceptions and current classroom activities in both Florida and the Caribbean territories; surveys of professional urban and land-use planners across Florida regarding their understanding of related in their professional practice; and conducting an inventory of relevant educational materials and information resources. Survey results showed a range of misperceptions about climate change, its causes and its likely impacts. At present, students and teachers in high and middle schools show poor understanding of climate science, and minimal time is spent in instruction on climate change in science courses in Florida and Puerto Rico schools. Also, there has to be professional development efforts and access to rich instructional content in a continuum spanning schools and professional communities including planners (which we surveyed). Architects and engineers are communities that also need to be surveyed and included in future efforts. A major obstacle to efforts at providing continuing education for planners and municipal officials is the lack of consensus on and access to regionally-specific scientific data regarding climate impacts and the relevant instructional content. It is difficult for professionals to prepare for climate change if they cannot define impacts in the Florida-Caribbean region and its coastal urban areas. Across over 1000

  5. General circulation and climate changes in the Mid-European area

    International Nuclear Information System (INIS)

    Schubert, S.; Hupfer, P.

    1992-01-01

    The long-term changes in the frequency distribution of weather patterns ('Grosswetterlage') are closely related to recent climate variations in the investigation area. However, this simple recording of weather pattern frequency changes is not enough for the complete explanation of the climatic changes which took place in our century in central Europe. One of the causes is the large variability of the weather for identical flow directions. In the case of weather situations which are linked to a low cloudiness degree, especially the temperature is strongly dependent on the duration of the 'Grosswetterlage'. Also when viewed from a long-term view, the climatic characteristics of the GWL air masses are by no means constant. If one considers the course of climate elements under identical circulation conditions, it is found that the average weather sometimes varied considerably in the course of the century although the general flow direction was the same. (orig./KW) [de

  6. Effects of volcanic eruptions on China's monsoon precipitation over the past 700 years

    Science.gov (United States)

    Zhuo, Z.; Gao, C.

    2013-12-01

    illustrates the effectiveness of MADA in reflecting China's hydrological condition during the summer monsoon season. On the other hand, with only SH injection, north and east china turn to wet in the eruption year and show a southward movement of the wettest areas, when compared to NH injection more than 2×Pinatubo. This spatial difference may shed some light on the possible effects stratospheric geoengineering may have on China's precipitation. References: Cook, E. R., et al. (2010), Asian Monsoon Failure and Megadrought During the Last Millennium, Science, 328(5977), 486-489. Crowley, T. J., and M. B. Unterman (2013), Technical details concerning development of a 1200 yr proxy index for global volcanism, Earth System Science Data, 5(1), 187-197. Gao, C. C., et al. (2008), Volcanic forcing of climate over the past 1500 years: An improved ice core-based index for climate models, J Geophys Res, 113(D23111D23).

  7. Apparent Trends in Productivity of Monsoon Asia from 1982 to 2002

    Science.gov (United States)

    Alexandrov, G. A.; Yamagata, Y.

    2005-12-01

    The rapid economic growth of Monsoon Asia raises concerns about the future of carbon stored in the terrestrial ecosystems of the region, especially in connection with climate change. The regional carbon budget for 1980s suggests that Monsoon Asia as a whole acted as source [Tian et al., 2003], although some parts of the region acted as sink. Here we provide some evidence from satellite data that productivity of the region changed in the manner that suggests similar conclusion. Comparing the period 1982-1992 and the period 1992-2002, we found that the productivity of the territory generally decreased in the forest zone and increased in the non-forest zone of the region. The productivity of a territory strongly depends on the area covered with photosynthetically active vegetation (PAV) and, therefore, we introduce a grid variable, FPAV, which stands for the fraction of a grid cell covered with PAV. (Grid, here, means geographic grid of half-degree resolution.) Deciduous plants are leafless during the dormant season, and so FPAV may vary on seasonal basis. The amplitude enlarges with the ratio between deciduous and evergreen species. The minimal value of FPAV gives the fraction of a grid cell covered with evergreen vegetation. The maximal value gives the fraction of the cell that covered either with deciduous or evergreen vegetation and, thus, tells us which fraction of the cell is vegetated. The changes in FPAV were tracked by using monthly values of AVHRR-NDVI for the period from July 1981 to December 2002 that were recently compiled into a public data set, so called GIMMS-NDVI [see Slayback et al., 2003 and references therein]. We calculated average monthly values of GIMMS-NDVI for two 11-year periods: from 1982 to 1992 and from 1992 to 2002, and used them to evaluate the trends in productivity of the region, characterized by the product of FPAVmax and Pn, where Pn is net primary production of potential natural vegetation, calculated by using TsuBiMo-model, FPAVmax

  8. Detection of the Coupling between Vegetation Leaf Area and Climate in a Multifunctional Watershed, Northwestern China

    Directory of Open Access Journals (Sweden)

    Lu Hao

    2016-12-01

    Full Text Available Accurate detection and quantification of vegetation dynamics and drivers of observed climatic and anthropogenic change in space and time is fundamental for our understanding of the atmosphere–biosphere interactions at local and global scales. This case study examined the coupled spatial patterns of vegetation dynamics and climatic variabilities during the past three decades in the Upper Heihe River Basin (UHRB, a complex multiple use watershed in arid northwestern China. We apply empirical orthogonal function (EOF and singular value decomposition (SVD analysis to isolate and identify the spatial patterns of satellite-derived leaf area index (LAI and their close relationship with the variability of an aridity index (AI = Precipitation/Potential Evapotranspiration. Results show that UHRB has become increasingly warm and wet during the past three decades. In general, the rise of air temperature and precipitation had a positive impact on mean LAI at the annual scale. At the monthly scale, LAI variations had a lagged response to climate. Two major coupled spatial change patterns explained 29% and 41% of the LAI dynamics during 1983–2000 and 2001–2010, respectively. The strongest connections between climate and LAI were found in the southwest part of the basin prior to 2000, but they shifted towards the north central area afterwards, suggesting that the sensitivity of LAI to climate varied over time, and that human disturbances might play an important role in altering LAI patterns. At the basin level, the positive effects of regional climate warming and precipitation increase as well as local ecological restoration efforts overwhelmed the negative effects of overgrazing. The study results offer insights about the coupled effects of climatic variability and grazing on ecosystem structure and functions at a watershed scale. Findings from this study are useful for land managers and policy makers to make better decisions in response to climate

  9. 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.

  10. Asian monsoon variability, cyclicities, and forcing mechanisms

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.

    in monsoonal intensity from 5 to 2Ma. Uplift of the Himalayas and the Tibetan Plateau occurred coeval with the increase in strength of the Asian Monsoon between 9.5 and 5Ma. Variability of monsoon on glacial and interglacial time scale Multi proxy based... in the Western Ghats of India 131 Fig. 3. Multi proxy monsoon reconstructions show that summer monsoon strength was stronger during interglacials (shaded intervals) as compared to glacials 0 2 4 6 8 10 12 14 16 18 20 0 100 200 300 400 0 50...

  11. Multi-decadal modulation of the El Nino-Indian monsoon relationship by Indian Ocean variability

    International Nuclear Information System (INIS)

    Ummenhofer, Caroline C; Sen Gupta, Alexander; Li Yue; Taschetto, Andrea S; England, Matthew H

    2011-01-01

    The role of leading modes of Indo-Pacific climate variability is investigated for modulation of the strength of the Indian summer monsoon during the period 1877-2006. In particular, the effect of Indian Ocean conditions on the relationship between the El Nino-Southern Oscillation (ENSO) and the Indian monsoon is explored. Using an extended classification for ENSO and Indian Ocean dipole (IOD) events for the past 130 years and reanalyses, we have expanded previous interannual work to show that variations in Indian Ocean conditions modulate the ENSO-Indian monsoon relationship also on decadal timescales. El Nino events are frequently accompanied by a significantly reduced Indian monsoon and widespread drought conditions due to anomalous subsidence associated with a shift in the descending branch of the zonal Walker circulation. However, for El Nino events that co-occur with positive IOD (pIOD) events, Indian Ocean conditions act to counter El Nino's drought-inducing subsidence by enhancing moisture convergence over the Indian subcontinent, with an average monsoon season resulting. Decadal modulations of the frequency of independent and combined El Nino and pIOD events are consistent with a strengthened El Nino-Indian monsoon relationship observed at the start of the 20th century and the apparent recent weakening of the El Nino-Indian monsoon relationship.

  12. Multi-decadal modulation of the El Nino-Indian monsoon relationship by Indian Ocean variability

    Energy Technology Data Exchange (ETDEWEB)

    Ummenhofer, Caroline C; Sen Gupta, Alexander; Li Yue; Taschetto, Andrea S; England, Matthew H, E-mail: c.ummenhofer@unsw.edu.au [Climate Change Research Centre, University of New South Wales, Sydney (Australia)

    2011-07-15

    The role of leading modes of Indo-Pacific climate variability is investigated for modulation of the strength of the Indian summer monsoon during the period 1877-2006. In particular, the effect of Indian Ocean conditions on the relationship between the El Nino-Southern Oscillation (ENSO) and the Indian monsoon is explored. Using an extended classification for ENSO and Indian Ocean dipole (IOD) events for the past 130 years and reanalyses, we have expanded previous interannual work to show that variations in Indian Ocean conditions modulate the ENSO-Indian monsoon relationship also on decadal timescales. El Nino events are frequently accompanied by a significantly reduced Indian monsoon and widespread drought conditions due to anomalous subsidence associated with a shift in the descending branch of the zonal Walker circulation. However, for El Nino events that co-occur with positive IOD (pIOD) events, Indian Ocean conditions act to counter El Nino's drought-inducing subsidence by enhancing moisture convergence over the Indian subcontinent, with an average monsoon season resulting. Decadal modulations of the frequency of independent and combined El Nino and pIOD events are consistent with a strengthened El Nino-Indian monsoon relationship observed at the start of the 20th century and the apparent recent weakening of the El Nino-Indian monsoon relationship.

  13. Expansion of Protected Areas under Climate Change: An Example of Mountainous Tree Species in Taiwan

    Directory of Open Access Journals (Sweden)

    Wei-Chih Lin

    2014-11-01

    Full Text Available Tree species in mountainous areas are expected to shift their distribution upward in elevation in response to climate change, calling for a potential redesign of existing protected areas. This study aims to predict whether or not the distributions of two high-mountain tree species, Abies (Abies kawakamii and Tsuga (Tsuga chinensis var. formosana, will significantly shift upward due to temperature change, and whether current protected areas will be suitable for conserving these species. Future temperature change was projected for 15 different future scenarios produced from five global climate models. Shifts in Abies and Tsuga distributions were then predicted through the use of species distribution models (SDMs which included occurrence data of Abies and Tsuga, as well as seasonal temperature, and elevation. The 25 km × 25 km downscaled General Circulation Model (GCMs data for 2020–2039 produced by the Taiwan Climate Change Projection and Information Platform was adopted in this study. Habitat suitability in the study area was calculated using maximum entropy model under different climatic scenarios. A bootstrap method was applied to assess the parameter uncertainty of the maximum entropy model. In comparison to the baseline projection, we found that there are significant differences in suitable habitat distributions for Abies and Tsuga under seven of the 15 scenarios. The results suggest that mountainous ecosystems will be substantially impacted by climate change. We also found that the uncertainty originating from GCMs and the parameters of the SDM contribute most to the overall level of variability in species distributions. Finally, based on the uncertainty analysis and the shift in habitat suitability, we applied systematic conservation planning approaches to identify suitable areas to add to Taiwan’s protected area network.

  14. Regional climate models downscaling in the Alpine area with multimodel superensemble

    Directory of Open Access Journals (Sweden)

    D. Cane

    2013-05-01

    Full Text Available The climatic scenarios show a strong signal of warming in the Alpine area already for the mid-XXI century. The climate simulations, however, even when obtained with regional climate models (RCMs, are affected by strong errors when compared with observations, due both to their difficulties in representing the complex orography of the Alps and to limitations in their physical parametrization. Therefore, the aim of this work is to reduce these model biases by using a specific post processing statistic technique, in order to obtain a more suitable projection of climate change scenarios in the Alpine area. For our purposes we used a selection of regional climate models (RCMs runs which were developed in the framework of the ENSEMBLES project. They were carefully chosen with the aim to maximise the variety of leading global climate models and of the RCMs themselves, calculated on the SRES scenario A1B. The reference observations for the greater Alpine area were extracted from the European dataset E-OBS (produced by the ENSEMBLES project, which have an available resolution of 25 km. For the study area of Piedmont daily temperature and precipitation observations (covering the period from 1957 to the present were carefully gridded on a 14 km grid over Piedmont region through the use of an optimal interpolation technique. Hence, we applied the multimodel superensemble technique to temperature fields, reducing the high biases of RCMs temperature field compared to observations in the control period. We also proposed the application of a brand new probabilistic multimodel superensemble dressing technique, already applied to weather forecast models successfully, to RCMS: the aim was to estimate precipitation fields, with careful description of precipitation probability density functions conditioned to the model outputs. This technique allowed for reducing the strong precipitation overestimation, arising from the use of RCMs, over the Alpine chain and to

  15. Dynamics in Protected Areas and Domesticated Landscapes Caused by Climate Change and Anthropogenic Use

    Science.gov (United States)

    Hartter, J.; Ryan, S.; Stampone, M.; Chapman, C.

    2009-12-01

    Climate change, a key factor of concern for conservation, has important biological and social implications. Africa’s Albertine Rift is an area of extremely high endemic biodiversity and is classed as a world conservation priority. However, natural areas are represented by a chain of protected forest areas in a matrix of intensive smallholder agriculture and dense human settlements. Kibale National Park in western Uganda has become an island of forest surrounded by intensive small-scale agriculture and is the only remaining large area of mid-altitude forest remaining in Albertine Rift Region and East Africa. Increased temperature and precipitation over recent decades has been observed by scientists and local farmers, however, to date, rigorous analysis of local climate data and the impact of climate change on local resources does not exist. Moreover, local farmers report that some crops die or ripen too early because of increased precipitation. Conservation biologists and park managers are concerned that changes in tree phenology and primary productivity will alter wildlife feeding preferences and ranges leading to more human-wildlife conflict. Understanding the impact of local and regional climate change and variation within the social, conservation, and geographic context is necessary to construct informed management plans and to maintain positive park-people relationships. This paper describes our first attempt to fully integrate multiple temporal and spatial datasets, and our progress in developing an interdisciplinary framework to study social and ecological relationships in the Kibale landscape. We examine historical in situ climate data and proxy climate information derived from remotely sensed satellite-borne imagery in our preliminary analyses. Our goal is to link these data with both pre-existing imagery analyses and tree community composition and phenology data from 39 years of ongoing research to identify the pattern, trajectory, and drivers of local

  16. Regional climate models downscaling in the Alpine area with multimodel superensemble

    Science.gov (United States)

    Cane, D.; Barbarino, S.; Renier, L. A.; Ronchi, C.

    2013-05-01

    The climatic scenarios show a strong signal of warming in the Alpine area already for the mid-XXI century. The climate simulations, however, even when obtained with regional climate models (RCMs), are affected by strong errors when compared with observations, due both to their difficulties in representing the complex orography of the Alps and to limitations in their physical parametrization. Therefore, the aim of this work is to reduce these model biases by using a specific post processing statistic technique, in order to obtain a more suitable projection of climate change scenarios in the Alpine area. For our purposes we used a selection of regional climate models (RCMs) runs which were developed in the framework of the ENSEMBLES project. They were carefully chosen with the aim to maximise the variety of leading global climate models and of the RCMs themselves, calculated on the SRES scenario A1B. The reference observations for the greater Alpine area were extracted from the European dataset E-OBS (produced by the ENSEMBLES project), which have an available resolution of 25 km. For the study area of Piedmont daily temperature and precipitation observations (covering the period from 1957 to the present) were carefully gridded on a 14 km grid over Piedmont region through the use of an optimal interpolation technique. Hence, we applied the multimodel superensemble technique to temperature fields, reducing the high biases of RCMs temperature field compared to observations in the control period. We also proposed the application of a brand new probabilistic multimodel superensemble dressing technique, already applied to weather forecast models successfully, to RCMS: the aim was to estimate precipitation fields, with careful description of precipitation probability density functions conditioned to the model outputs. This technique allowed for reducing the strong precipitation overestimation, arising from the use of RCMs, over the Alpine chain and to reproduce well the

  17. Future climate and wildfire: ecosystem projections of area burned in the western US

    Science.gov (United States)

    Littell, J. S.; Duffy, P.; Battisti, D. S.; McKenzie, D.; Peterson, D. L.

    2010-12-01

    The area burned by fire in ecosystems of the western United States has been closely linked to climate in the paleoecological record and in the modern record. Statistical models of area burned show that the climatic controls on area burned vary with vegetation type (Littell et al. 2009). In more arid or systems (grasslands, shrublands, woodlands), antecedent climatic controls on fire were associated first with the production of fuels and secondarily with drought in the year of fire. These relationships typically manifested as wetter and sometimes cooler conditions in the seasons prior to the fire season. Area burned in forest ecosystems and some woodlands was primarily associated with drought conditions, specifically increased temperature and decreased precipitation in the year of fire and the seasons leading up to the fire season. These climatic controls indicate the role of climate in drying existing fuels. Statistical fire models trained on the late 20th century for ecoprovinces in the West would be useful for projecting area burned, at least until vegetation type conversion driven by climate and disturbance occurs. To that end, we used ~ 2.5 degree gridded future climate fields derived for a multi-GCM ensemble of 1C and 2C temperature increase forcing to develop future ecoprovince monthly and seasonal average temperature and associated precipitation and used these as predictors in statistical fire models of future projected area burned. We also conducted modeling scenarios with the ensemble temperature increase paired with historical precipitation. Most ecoprovinces had increases in area burned, with a range of ~ 67% to over 600% . Ecoprovinces that are primarily sensitive to precipitation changes exhibit smaller increases than those most sensitive to temperature (forest systems). We also developed exceedance probabilities. Some ecoprovinces show large increases in area burned but low exceedance probabilities, suggest that the area burned is concentrated more

  18. Climate change impact on fire probability and severity in Mediterranean areas

    Science.gov (United States)

    Bachisio Arca; Grazia Pellizzaro; Pierpaolo Duce; Michele Salis; Valentina Bacciu; Donatella Spano; Alan Ager; Mark Finney

    2010-01-01

    Fire is one of the most significant threats for the Mediterranean forested areas. Global change may increase the wildland fire risk due to the combined effect of air temperature and humidity on fuel status, and the effect of wind speed on fire behaviour. This paper investigated the potential effect of the climate changes predicted for the Mediterranean basin by a...

  19. Regional Spectral Model simulations of the summertime regional climate over Taiwan and adjacent areas

    Science.gov (United States)

    Ching-Teng Lee; Ming-Chin Wu; Shyh-Chin Chen

    2005-01-01

    The National Centers for Environmental Prediction (NCEP) regional spectral model (RSM) version 97 was used to investigate the regional summertime climate over Taiwan and adjacent areas for June-July-August of 1990 through 2000. The simulated sea-level-pressure and wind fields of RSM1 with 50-km grid space are similar to the reanalysis, but the strength of the...

  20. Climate change impacts on extreme temperature mortality in select metropolitan areas of the United States

    Science.gov (United States)

    Projected mortality from climate change-driven impacts on extremely hot and cold days increases significantly over the 21st century in a large group of United States Metropolitan Statistical Areas. Increases in projected mortality from more hot days are greater than decreases in ...

  1. Sensitivity of burned area in Europe to climate change, atmospheric CO2 levels, and demography

    DEFF Research Database (Denmark)

    Wu, Minchao; Knorr, Wolfgang; Thonicke, Kirsten

    2015-01-01

    model. Applying a range of future projections that combine different scenarios for climate changes, enhanced CO2 concentrations, and population growth, we investigated the individual and combined effects of these drivers on the total area and regions affected by fire in the 21st century. The two models...

  2. Regional relationships between climate and wildfire-burned area in the interior West, USA

    Science.gov (United States)

    Brandon M. Collins; Philip N. Omi; Phillip L. Chapman

    2006-01-01

    Recent studies have linked the Atlantic Multtidecadal Oscillation (AMO) and the Pacific Decadal Oscillation (PDO) with drought occurrence in the interior United States. This study evaluates the influence of AM0 and PDO phases on interannual relationships between climate and wildfire-burned area during the 20th century. Palmer's Drought Severity Index (PDSI) is...

  3. AMS 14 C dating controlled records of monsoon and Indonesian throughflow variability from the eastern Indian Ocean of the past 32,000 years

    Science.gov (United States)

    Li, Z. Y.; Chen, M. T.; Shi, X.; Liu, S.; Wang, H.

    2015-12-01

    Zi-Ye Li a, Min-Te Chen b, Hou-Jie Wang a, Sheng-Fa Liu c, Xue-Fa Shi ca College of Marine Geosciences, Ocean University of China, Qingdao 266100, P.R. Chinab Institute of Applied Geosciences, National Taiwan Ocean University, Keelung, Taiwan 20224, ROCc First Institute of Oceanography, SOA, Qingdao 266100, P.R. China Indonesian throughflow (ITF) is one of the most important currents responsible for transporting heat and moisture from the western Pacific to the Indian Oceans. The ITF is also well-known as effectively in modulating the global climate change with the interactions among ENSO and Asian monsoons. Here we present an AMS 14C dating controlled sea surface temperature (SST) record from core SO184-10043 (07°18.57'S, 105°03.53'E), which was retrieved from 2171m water depth at a north-south depression located at the southeastern offshore area of Sumatera in the eastern Indian Ocean. Based on our high-resolution SST using Mg/Ca analyses based on planktonic foraminifera shells of Globigerinoides ruber and alkenone index, U k'37-SST, oxygen isotope stratigraphy, and AMC 14C age-controls, our records show that, during the past 32,000 years, the SSTs were decreased which imply weaker ITF during Marine Isotope Stage (MIS) 2 and 3. The weaker UTF may respond to strengthened northeast monsoon during the boreal winter. During 21 to 15ka, the southeast monsoon had been stronger and the northeast monsoon was relatively weaker. During 15 to 8ka, rapid sea level rising may allow the opening of the gateways in the Makassar Strait and Lombok Strait that may have further strengthened the ITF. During the early Holocene, the northeast and southeast monsoons seem to be both strengthened. We will discuss the implications of the hydrographic variability and their age uncertainties in this paper during the meeting.

  4. Ecological strategies in california chaparral: Interacting effects of soils, climate, and fire on specific leaf area

    Science.gov (United States)

    Anacker, Brian; Rajakaruna, Nishanta; Ackerly, David; Harrison, Susan; Keeley, Jon E.; Vasey, Michael

    2011-01-01

    Background: High values of specific leaf area (SLA) are generally associated with high maximal growth rates in resource-rich conditions, such as mesic climates and fertile soils. However, fire may complicate this relationship since its frequency varies with both climate and soil fertility, and fire frequency selects for regeneration strategies (resprouting versus seeding) that are not independent of resource-acquisition strategies. Shared ancestry is also expected to affect the distribution of resource-use and regeneration traits.Aims: We examined climate, soil, and fire as drivers of community-level variation in a key functional trait, SLA, in chaparral in California.Methods: We quantified the phylogenetic, functional, and environmental non-independence of key traits for 87 species in 115 plots.Results: Among species, SLA was higher in resprouters than seeders, although not after phylogeny correction. Among communities, mean SLA was lower in harsh interior climates, but in these climates it was higher on more fertile soils and on more recently burned sites; in mesic coastal climates, mean SLA was uniformly high despite variation in soil fertility and fire history.Conclusions: We conclude that because important correlations exist among both species traits and environmental filters, interpreting the functional and phylogenetic structure of communities may require an understanding of complex interactive effects.

  5. Monsoon effect simulation on typhoon rainfall potential - Typhoon Morakot (2009

    Directory of Open Access Journals (Sweden)

    Yi-Ling Chang

    2017-01-01

    Full Text Available A record breaking extreme precipitation event produced 3000 mm day-1 of accumulated rainfall over southern Taiwan in August 2009. The interactions between Typhoon Morakot and the prevailing southwesterly (SW monsoon are the primary mechanism for this heavy precipitation during 5 - 13 August 2009. This extreme precipitation could be produced by the abundant moisture from the SW monsoon associated with the interaction between typhoon and monsoon wind fields, leading to severe property damage. The accurate mapping of extreme precipitation caused from the interaction between a monsoon and typhoon is critical for early warning in Taiwan. This study simulates the heavy rainfall event is based on the Weather Research and Forecast system model (WRF using the three nested domain configuration. Using data assimilation with a virtual meteorological field using the 3D-Var system, such as wind field to alter the SW monsoon strength in the initial condition, the impacts of intensified convergence and water vapor content on the accumulated rainfall are analyzed to quantize the intensification of typhoon rainfall potential. The results showed a positive correlation between the enhanced precipitation and the intensity of low-level wind speed convergence as well as water vapor content. For the Typhoon Morakot case study the rainfall for could attain approximately 2 × 104 mm at 6 hours interval in the southern Taiwan area when 10 × 10-6 s-1 convergence intensified at 850 hPa level around the southern part of the Taiwan Strait. These results suggest that low-level wind speed, convergence and water vapor content play key roles in the typhoon rainfall potential coupled with the SW monsoon.

  6. Modelling plant invasion pathways in protected areas under climate change: implication for invasion management

    Directory of Open Access Journals (Sweden)

    C.-J. Wang

    2017-12-01

    Full Text Available Global climate change may enable invasive plant species (IPS to invade protected areas (PAs, but plant invasion on a global scale has not yet been explicitly addressed. Here, we mapped the potential invasion pathways for IPS in PAs across the globe and explored potential factors determining the pathways of plant invasion under climate change. We used species distribution modelling to estimate the suitable habitats of 386 IPS and applied a corridor analysis to compute the potential pathways of IPS in PAs under climate change. Subsequently, we analysed the potential factors affecting the pathways in PAs. According to our results, the main potential pathways of IPS in PAs are in Europe, eastern Australia, New Zealand, southern Africa, and eastern regions of South America and are strongly influenced by changes in temperature and precipitation. Protected areas can play an important role in preventing and controlling the spread of IPS under climate change. This is due to the fact that measures are taken to monitor climate change in detail, to provide effective management near or inside PAs, and to control the introduction of IPS with a high capacity for natural dispersal. A review of conservation policies in PAs is urgently needed.

  7. The East Asian Atmospheric Water Cycle and Monsoon Circulation in the Met Office Unified Model

    Science.gov (United States)

    Rodríguez, José M.; Milton, Sean F.; Marzin, Charline

    2017-10-01

    In this study the low-level monsoon circulation and observed sources of moisture responsible for the maintenance and seasonal evolution of the East Asian monsoon are examined, studying the detailed water budget components. These observational estimates are contrasted with the Met Office Unified Model (MetUM) climate simulation performance in capturing the circulation and water cycle at a variety of model horizontal resolutions and in fully coupled ocean-atmosphere simulations. We study the role of large-scale circulation in determining the hydrological cycle by analyzing key systematic errors in the model simulations. MetUM climate simulations exhibit robust circulation errors, including a weakening of the summer west Pacific Subtropical High, which leads to an underestimation of the southwesterly monsoon flow over the region. Precipitation and implied diabatic heating biases in the South Asian monsoon and Maritime Continent region are shown, via nudging sensitivity experiments, to have an impact on the East Asian monsoon circulation. By inference, the improvement of these tropical biases with increased model horizontal resolution is hypothesized to be a factor in improvements seen over East Asia with increased resolution. Results from the annual cycle of the hydrological budget components in five domains show a good agreement between MetUM simulations and ERA-Interim reanalysis in northern and Tibetan domains. In simulations, the contribution from moisture convergence is larger than in reanalysis, and they display less precipitation recycling over land. The errors are closely linked to monsoon circulation biases.

  8. Estimating future burned areas under changing climate in the EU-Mediterranean countries.

    Science.gov (United States)

    Amatulli, Giuseppe; Camia, Andrea; San-Miguel-Ayanz, Jesús

    2013-04-15

    The impacts of climate change on forest fires have received increased attention in recent years at both continental and local scales. It is widely recognized that weather plays a key role in extreme fire situations. It is therefore of great interest to analyze projected changes in fire danger under climate change scenarios and to assess the consequent impacts of forest fires. In this study we estimated burned areas in the European Mediterranean (EU-Med) countries under past and future climate conditions. Historical (1985-2004) monthly burned areas in EU-Med countries were modeled by using the Canadian Fire Weather Index (CFWI). Monthly averages of the CFWI sub-indices were used as explanatory variables to estimate the monthly burned areas in each of the five most affected countries in Europe using three different modeling approaches (Multiple Linear Regression - MLR, Random Forest - RF, Multivariate Adaptive Regression Splines - MARS). MARS outperformed the other methods. Regression equations and significant coefficients of determination were obtained, although there were noticeable differences from country to country. Climatic conditions at the end of the 21st Century were simulated using results from the runs of the regional climate model HIRHAM in the European project PRUDENCE, considering two IPCC SRES scenarios (A2-B2). The MARS models were applied to both scenarios resulting in projected burned areas in each country and in the EU-Med region. Results showed that significant increases, 66% and 140% of the total burned area, can be expected in the EU-Med region under the A2 and B2 scenarios, respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Assessing the level of spatial homogeneity of the agronomic Indian monsoon onset

    Science.gov (United States)

    Fitzpatrick, Rory G. J.; Parker, Douglas J.; Willetts, Peter D.

    2016-11-01

    Over monsoon regions, such as the Indian subcontinent, the local onset of persistent rainfall is a crucial event in the annual climate for agricultural planning. Recent work suggested that local onset dates are spatially coherent to a practical level over West Africa; a similar assessment is undertaken here for the Indian subcontinent. Areas of coherent onset, defined as local onset regions or LORs, exist over the studied region. These LORs are significant up to the 95% confidence interval and are primarily clustered around the Arabian Sea (adjacent to and extending over the Western Ghats), the Monsoon Trough (north central India), and the Bay of Bengal. These LORs capture regions where synoptic scale controls of onset may be present and identifiable. In other regions, the absence of LORs is indicative of regions where local and stochastic factors may dominate onset. A potential link between sea surface temperature anomalies and LOR variability is presented. Finally, Kerala, which is often used as a representative onset location, is not contained within an LOR suggesting that variability here may not be representative of wider onset variability.

  10. The sensitivity of the Indian summer monsoon to a global warming of 2 C with respect to pre-industrial times

    Energy Technology Data Exchange (ETDEWEB)

    May, Wilhelm [Danish Meteorological Institute, Danish Climate Centre, Copenhagen (Denmark)

    2011-11-15

    In this study the potential future changes in different aspects of the Indian summer monsoon associated with a global warming of 2 C with respect to pre-industrial times are assessed, focussing on the role of the different mechanisms leading to these changes. In addition, these changes as well as the underlying mechanisms are compared to the corresponding changes associated with a markedly stronger global warming exceeding 4.5 C, associated with the widely used SRES A1B scenario. The study is based on two sets of four ensemble simulations with the ECHAM5/MPI-OM coupled climate model, each starting from different initial conditions. In one set of simulations (2020-2200), greenhouse gas concentrations and sulphate aerosol load have been prescribed in such a way that the simulated global warming does not exceed 2 C with respect to pre-industrial times. In the other set of simulations (1860-2200), greenhouse gas concentrations and sulphate aerosol load have been prescribed according to observations until 2000 and according to the SRES A1B scenario after 2000. The study reveals marked changes in the Indian summer monsoon associated with a global warming of 2 C with respect to pre-industrial conditions, namely an intensification of the summer monsoon precipitation despite a weakening of the large-scale monsoon circulation. The increase in the monsoon rainfall is related to a variety of different mechanisms, with the intensification of the atmospheric moisture transport into the Indian region as the most important one. The weakening of the large-scale monsoon circulation is mainly caused by changes in the Walker circulation with large-scale divergence (convergence) in the lower (upper) troposphere over the Indian Ocean in response to enhanced convective activity over the Indian Ocean and the central and eastern Pacific and reduced convective activity over the western tropical Pacific. These changes in the Walker circulation induce westerly (easterly) wind anomalies at

  11. Climate Prediction Center

    Science.gov (United States)

    Weather Service NWS logo - Click to go to the NWS home page Climate Prediction Center Home Site Map News Organization Enter Search Term(s): Search Search the CPC Go NCEP Quarterly Newsletter Climate Highlights U.S Climate-Weather El Niño/La Niña MJO Blocking AAO, AO, NAO, PNA Climatology Global Monsoons Expert

  12. Climate Change and its Impacts on Tourism and Livelihood in Manaslu Conservation Area, Nepal

    Science.gov (United States)

    K C, A.

    2016-12-01

    The Hindukush Himalayan region including Nepal, a country reliant on tourism, is particularly sensitive to climate change. However, there are considerable gaps in research regarding tourism, livelihood and climate change in Nepal. The present research assesses the impact of climate change on tourism and livelihood in the Manaslu Conservation Area (MCA) of Nepal. Seventy-six households were interviewed followed by three focus group discussions and five key informant interviews. The empirical data collected at the site are complemented by secondary scientific data on climate and tourism. Correlation, regression, descriptive and graphical analysis was carried out for the presentation and analysis of data. Local people perceived that temperature and rainfall have been increasing in the study site as a result of climate change. It was also verified by the observed scientific data of temperature and precipitation. Socioeconomic variables such as marital status, size of household, education and landholding status had positive effect on tourism participation while livestock-holding status and occupation of the household had negative effect on tourism participation. Number of visitors is increasing in MCA in recent years, and tourism participation is helping local people to earn more money and improve their living standard. Till the date, there is positive impact of climate change on tourism sector in the study area. But, unfavorable weather change phenomena, intense rainfall and snowfall, melting of snow, occurrence of hydrological and climatic hazards and increase in temperature may have adverse impact on the tourism and livelihood in the mountainous area. Such type of adverse impact of climate change and tourism is already experienced in the case of Annapurna region and Mt. Everest region as tourist were trapped and affected by unfavorable weather change phenomena. In response to gradually warming temperature and decreasing snowfall, there seems an urgent need for

  13. Climate change and its impact on the Crn Drim Catchment Area In Macedonia

    International Nuclear Information System (INIS)

    Todorovik, Oliviia; Aleksovska, Nina; Rikaloska, Gorica

    2004-01-01

    In this paper it will be presented the overview of the climate change and climate regimes of the world in general according different scenarios in the latest assessment (the 3d Report published in 2001) of the Intergovernmental Panel on Climate Change (IPCC) and its impact on the Crn Drim catchment area in Macedonia.This analysis and interpretation only provides a preliminary investigation into climate change and how it will affect Ohrid and Prespa lake system as a part of Crn Drim catchment area, which is already attacked by the climate changed. From the climatological aspect two elements: temperature and rainfall, will be' calculated and their expected changes over the century in the same area. Dates used in these analyses are from the Hydro meteorological Service of Republic of Macedonia archives In the graphs are shown changes in average seasonal climate for the period around the 2080s, relative to 1961-1990 climate. Results are shown for the SRES A2 scenario, which assumes a future world of fairly conventional energy development, i.e., continuing dependence on fossil carbon fuels. The projections for average seasonal climate for temperature and precipitation are estimated and shown separately for two seasons: winter and summer. The estimated values are compared with annual mean global worming for the 2080s,-and for the SRES A2 scenario, as calculated by the IPCC (a value of about 3.2 o C). The results show rate of worming greater in summer than in winter for Ohrid Lake as well as for Prespa Lake. Concerning the precipitation, it increases slightly in winter and decreases substantially in summer, by around 30 per cent. As the conclusion it is obviously that the temperature will rise in all Crn Drim catchment area with implications for increasing water temperature and water quality, which would be degraded by higher water temperature. This will increase evaporation and as the results can be expected water level decreasing. Also, higher temperatures and heat

  14. Biodiversity Areas under Threat: Overlap of Climate Change and Population Pressures on the World's Biodiversity Priorities.

    Science.gov (United States)

    Aukema, Juliann E; Pricope, Narcisa G; Husak, Gregory J; Lopez-Carr, David

    2017-01-01

    Humans and the ecosystem services they depend on are threatened by climate change. Places with high or growing human population as well as increasing climate variability, have a reduced ability to provide ecosystem services just as the need for these services is most critical. A spiral of vulnerability and ecosystem degradation often ensues in such places. We apply different global conservation schemes as proxies to examine the spatial relation between wet season precipitation, population change over three decades, and natural resource conservation. We pose two research questions: 1) Where are biodiversity and ecosystem services vulnerable to the combined effects of climate change and population growth? 2) Where are human populations vulnerable to degraded ecosystem services? Results suggest that globally only about 20% of the area between 50 degrees latitude North and South has experienced significant change-largely wetting-in wet season precipitation. Approximately 40% of rangelands and 30% of rainfed agriculture lands have experienced significant precipitation changes, with important implications for food security. Over recent decades a number of critical conservation areas experienced high population growth concurrent with significant wetting or drying (e.g. the Horn of Africa, Himalaya, Western Ghats, and Sri Lanka), posing challenges not only for human adaptation but also to the protection and sustenance of biodiversity and ecosystem services. Identifying areas of climate and population risk and their overlap with conservation priorities can help to target activities and resources that promote biodiversity and ecosystem services while improving human well-being.

  15. Heat-stress increase under climate change twice as large in cities as in rural areas

    Science.gov (United States)

    Wouters, Hendrik; De Ridder, Koen; Poelmans, Lien; Willems, Patrick; Brouwers, Johan; Hosseinzadehtalaei, Parisa; Tabari, Hossein; Vanden Broucke, Sam; van Lipzig, Nicole P. M.; Demuzere, Matthias

    2017-04-01

    Urban areas, being warmer than their surroundings, are particularly vulnerable to global warming and associated increases in extreme temperatures. Yet ensemble climate-model projections are generally performed on a scale that is too coarse to represent the evolution of temperatures in cities. Here, for the first time, we combine a 35-year convection-permitting climate model integrations with information from an ensemble of general circulation models to assess heat stress in a typical densely populated mid-latitude maritime region. We show that the heat-stress increase for the mid-21st century is twice as large in cities compared to their surrounding rural areas. The exacerbation is driven by the urban heat island itself, its concurrence with heatwaves, and urban expansion. Cities experience a heat-stress multiplication by a factor 1.4 and 15 depending on the scenario. Remarkably, the future heat-stress surpasses everywhere the urban hot spots of today. Our novel insights exemplify the need to combine information from climate models, acting on different scales, for climate-change risk assessment in heterogeneous regions. Moreover, these results highlight the necessity for adaptation to increasing heat stress, especially in urban areas.

  16. Biodiversity Areas under Threat: Overlap of Climate Change and Population Pressures on the World's Biodiversity Priorities.

    Directory of Open Access Journals (Sweden)

    Juliann E Aukema

    Full Text Available Humans and the ecosystem services they depend on are threatened by climate change. Places with high or growing human population as well as increasing climate variability, have a reduced ability to provide ecosystem services just as the need for these services is most critical. A spiral of vulnerability and ecosystem degradation often ensues in such places. We apply different global conservation schemes as proxies to examine the spatial relation between wet season precipitation, population change over three decades, and natural resource conservation. We pose two research questions: 1 Where are biodiversity and ecosystem services vulnerable to the combined effects of climate change and population growth? 2 Where are human populations vulnerable to degraded ecosystem services? Results suggest that globally only about 20% of the area between 50 degrees latitude North and South has experienced significant change-largely wetting-in wet season precipitation. Approximately 40% of rangelands and 30% of rainfed agriculture lands have experienced significant precipitation changes, with important implications for food security. Over recent decades a number of critical conservation areas experienced high population growth concurrent with significant wetting or drying (e.g. the Horn of Africa, Himalaya, Western Ghats, and Sri Lanka, posing challenges not only for human adaptation but also to the protection and sustenance of biodiversity and ecosystem services. Identifying areas of climate and population risk and their overlap with conservation priorities can help to target activities and resources that promote biodiversity and ecosystem services while improving human well-being.

  17. Rapid climatic shifts and its influence on ancient civilisations: Evidence from marine records

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.

    The southwest (SW) monsoon system in the Arabian Sea exerts a strong influence upon the climatic conditions in South and Southeast Asia and the associated monsoon rainfall has a great impact on the socio-economic and agricultural development...

  18. Evaluation of CFSV2 Forecast Skill for Indian Summer Monsoon Sub-Seasonal Characteristics

    Science.gov (United States)

    S, S. A.; Ghosh, S.

    2015-12-01

    Prediction of sub seasonal monsoon characteristics of Indian Summer Monsoon (ISM) is highly crucial for agricultural planning and water resource management. The Climate forecast System version 2 (CFS V2), the state of the art coupled climate model developed by NCEP, is currently being employed for the seasonal and extended range forecasts of ISM. Even though CFSV2 is a fully coupled ocean- atmosphere- land model with advanced physics, increased resolution and refined initialisation, its ISM forecasts, in terms of seasonal mean and variability needs improvement. Numerous works have been done for verifying the CFSV2 forecasts in terms of the seasonal mean, its mean and variability, active and break spells, and El Nino Southern Oscillation (ENSO) - monsoon interactions. Most of these works are based on either rain fall strength or rainfall based indices. Here we evaluate the skill of CFS v2 model in forecasting the various sub seasonal features of ISM, viz., the onset and withdrawal days of monsoon that are determined using circulation based indices, the Monsoon Intra Seasonal Oscillations (MISO), and Indian Ocean and Pacific Ocean sea surface temperatures. The MISO index, we use here, is based on zonal wind at 850 hPa and Outgoing Long wave Radiation (OLR) anomalies. With this work, we aim at assessing the skill of the model in simulating the large scale circulation patterns and their variabilities within the monsoon season. Variabilities in these large scale circulation patterns are primarily responsible for the variabilities in the seasonal monsoon strength and its temporal distribution across the season. We find that the model can better forecast the large scale circulation and than the actual precipitation. Hence we suggest that seasonal rainfall forecasts can be improved by the statistical downscaling of CFSV2 forecasts by incorporating the established relationships between the well forecasted large scale variables and monsoon precipitation.

  19. Seasonally asymmetric transition of the Asian monsoon in response to ice age boundary conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, Hiroaki; Kuroki, Harumitsu; Kamae, Youichi [University of Tsukuba, Graduate School of Life and Environmental Sciences, Tsukuba, Ibaraki (Japan); Ohba, Masamichi [Central Research Institute of Electric Power Industry, Environmental Science Research Laboratory, Abiko (Japan)

    2011-12-15

    Modulation of a monsoon under glacial forcing is examined using an atmosphere-ocean coupled general circulation model (AOGCM) following the specifications established by Paleoclimate Modelling Intercomparison Project phase 2 (PMIP2) to understand the air-sea-land interaction under different climate forcing. Several sensitivity experiments are performed in response to individual changes in the continental ice sheet, orbital parameters, and sea surface temperature (SST) in the Last Glacial Maximum (LGM: 21 ka) to evaluate the driving mechanisms for the anomalous seasonal evolution of the monsoon. Comparison of the model results in the LGM with the pre-industrial (PI) simulation shows that the Arabian Sea and Bay of Bengal are characterized by enhancement of pre-monsoon convection despite a drop in the SST encompassing the globe, while the rainfall is considerably suppressed in the subsequent monsoon period. In the LGM winter relative to the PI, anomalies in the meridional temperature gradient (MTG) between the Asian continents minus the tropical oceans become positive and are consistent with the intensified pre-monsoon circulation. The enhanced MTG anomalies can be explained by a decrease in the condensation heating relevant to the suppressed tropical convection as well as positive insolation anomalies in the higher latitude, showing an opposing view to a warmer future climate. It is also evident that a latitudinal gradient in the SST across the equator plays an important role in the enhancement of pre-monsoon rainfall. As for the summer, the sensitivity experiments imply that two ice sheets over the northern hemisphere cools the air temperature over the Asian continent, which is consistent with the reduction of MTG involved in the attenuated monsoon. The surplus pre-monsoon convection causes a decrease in the SST through increased heat loss from the ocean surface; in other words, negative ocean feedback is also responsible for the subsequent weakening of summer

  20. GMMIP (v1.0) contribution to CMIP6: Global Monsoons Model Inter-comparison Project

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Tianjun; Turner, Andrew G.; Kinter, James L.; Wang, Bin; Qian, Yun; Chen, Xiaolong; Wu, Bo; Wang, Bin; Liu, Bo; Zou, Liwei; He, Bian

    2016-10-10

    The Global Monsoons Model Inter-comparison Project (GMMIP) has been endorsed by the panel of Coupled Model Inter-comparison Project (CMIP) as one of the participating model inter-comparison projects (MIPs) in the sixth phase of CMIP (CMIP6). The focus of GMMIP is on monsoon climatology, variability, prediction and projection, which is relevant to four of the “Grand Challenges” proposed by the World Climate Research Programme. At present, 21 international modeling groups are committed to joining GMMIP. This overview paper introduces the motivation behind GMMIP and the scientific questions it intends to answer. Three tiers of experiments, of decreasing priority, are designed to examine (a) model skill in simulating the climatology and interannual-to-multidecadal variability of global monsoons forced by the sea surface temperature during historical climate period; (b) the roles of the Interdecadal Pacific Oscillation and Atlantic Multidecadal Oscillation in driving variations of the global and regional monsoons; and (c) the effects of large orographic terrain on the establishment of the monsoons. The outputs of the CMIP6 Diagnostic, Evaluation and Characterization of Klima experiments (DECK), “historical” simulation and endorsed MIPs will also be used in the diagnostic analysis of GMMIP to give a comprehensive understanding of the roles played by different external forcings, potential improvements in the simulation of monsoon rainfall at high resolution and reproducibility at decadal timescales. The implementation of GMMIP will improve our understanding of the fundamental physics of changes in the global and regional monsoons over the past 140 years and ultimately benefit monsoons prediction and projection in the current century.

  1. Cyclone trends constrain monsoon variability during late Oligocene sea level highstands (Kachchh Basin, NW India)

    Science.gov (United States)

    Reuter, M.; Piller, W. E.; Harzhauser, M.; Kroh, A.

    2013-09-01

    Climate change has an unknown impact on tropical cyclones and the Asian monsoon. Herein we present a sequence of fossil shell beds from the shallow-marine Maniyara Fort Formation (Kachcch Basin) as a recorder of tropical cyclone activity along the NW Indian coast during the late Oligocene warming period (~ 27-24 Ma). Proxy data providing information about the atmospheric circulation dynamics over the Indian subcontinent at this time are important since it corresponds to a major climate reorganization in Asia that ends up with the establishment of the modern Asian monsoon system at the Oligocene-Miocene boundary. The vast shell concentrations are comprised of a mixture of parautochthonous and allochthonous assemblages indicating storm-generated sediment transport from deeper to shallow water during third-order sea level highstands. Three distinct skeletal assemblages were distinguished, each recording a relative storm wave base. (1) A shallow storm wave base is shown by nearshore molluscs, reef corals and Clypeaster echinoids; (2) an intermediate storm wave base depth is indicated by lepidocyclinid foraminifers, Eupatagus echinoids and corallinacean algae; and (3) a deep storm wave base is represented by an Amussiopecten bivalve-Schizaster echinoid assemblage. These wave base depth estimates were used for the reconstruction of long-term tropical storm intensity during the late Oligocene. The development and intensification of cyclones over the recent Arabian Sea is primarily limited by the atmospheric monsoon circulation and strength of the associated vertical wind shear. Therefore, since the topographic boundary conditions for the Indian monsoon already existed in the late Oligocene, the reconstructed long-term cyclone trends were interpreted to reflect monsoon variability during the initiation of the Asian monsoon system. Our results imply an active monsoon over the Eastern Tethys at ~ 26 Ma followed by a period of monsoon weakening during the peak of the late

  2. Towards a New Policy for Climate Adaptive Water Management in Flanders: The Concept of Signal Areas

    Directory of Open Access Journals (Sweden)

    Peter De Smedt

    2014-05-01

    Full Text Available In Flanders, the Government has recently established an innovative policy framework to preserve the water storage capacity in flood-prone areas. In this context, the concept of ‘Signal Areas’ (signaalgebieden has been created. These areas are still undeveloped areas with a hard planning destination (residential and industrial areas located in flood-prone areas. The framework outlines in what way one needs to deal with the flood risk in these areas. The intention is to work with tailor-made solutions for each separate area. For this purpose, a comprehensive tool-box is available, such as land reparcelling, spatial destination or zoning swapping (bestemmingsruil, regulations regarding appropriate construction methods and land use in urban planning regulations or in public utility servitudes, and the application of a sharpened Water Test. The final objective is to create an efficacious, area-oriented adaptation strategy for climate-proof spatial planning. In this contribution, the author will provide an insight into the legal design of the above-mentioned concepts and instruments, how they can contribute to a stronger linkage between water management and spatial planning and therefore to a solid climate change adaptation strategy, as well as the factors of success and failure of this new policy framework.

  3. Hunza Landslide and Monsoon Flooding in Pakistan Call for International Attention to Transboundary Natural Hazards

    Science.gov (United States)

    Kargel, J. S.; Fink, W.; Furfaro, R.; Leonard, G. J.; Patterson, M.; Glims, Gaphaz

    2010-12-01

    Two major disasters in Pakistan and innumerable lesser disasters throughout the Himalaya-Karakoram region in 2010 highlight geologic events and extreme weather (perhaps climate change) in affecting the well being of whole nations and commerce and relations between nations. Two chief events in Pakistan include the Jan. 4 rockslide into the Hunza River and the subsequent formation of a natural dam lake (Lake Gojal); and the monsoon precipitation-fed flooding across the Indus Basin. The first event severed Pakistan’s major land link with China. The second event devastated Pakistan’s national land-based transportation infrastructure and agriculture and displaced millions of people. In a country plagued by monsoon-driven floods, the lack of catastrophic breakout of Lake Gojal is welcome. Satellite-based monitoring shows the spillway to be eroding more rapidly (but not alarmingly) under August’s monsoon peak flow. Similar events have occurred before in the region and will occur again. These mega-events in Pakistan should be an alert for all of South Asia, as climate change increases or shifts the hazard environment, encroaching development and urbanization increases the vulnerabilities, and as improved capacity for trans-national commerce breaks down the Himalayan barrier and both promotes new opportunities and possible conflicts. 2010's natural mega-calamities in Pakistan and widespread landsliding and flooding elsewhere in South Asia underscores the subcontinent’s need for a thorough field-, remote sensing-, and modeling-based assessment of the disaster potential related to landslides, glacier surges, extreme monsoon precipitation events, natural glacier and landslide dam lake outbursts, and unseasonal snow melting. The Himalayan-Karakoram region is remarkable for its heterogeneous responses to climate change. For instance, some areas are undergoing rapid glacier recession and stagnation; others are undergoing glacier growth. We take the instance of the

  4. Monsoon oscillations regulate fertility of the Red Sea

    KAUST Repository

    Raitsos, Dionysios E.

    2015-02-16

    Tropical ocean ecosystems are predicted to become warmer, more saline, and less fertile in a future Earth. The Red Sea, one of the warmest and most saline environments in the world, may afford insights into the function of the tropical ocean ecosystem in a changing planet. We show that the concentration of chlorophyll and the duration of the phytoplankton growing season in the Red Sea are controlled by the strength of the winter Arabian monsoon (through horizontal advection of fertile waters from the Indian Ocean). Furthermore, and contrary to expectation, in the last decade (1998-2010) the winter Red Sea phytoplankton biomass has increased by 75% during prolonged positive phases of the Multivariate El Niño-Southern Oscillation Index. A new mechanism is reported, revealing the synergy of monsoon and climate in regulating Red Sea greenness. © 2015 The Authors.

  5. Monsoon oscillations regulate fertility of the Red Sea

    KAUST Repository

    Raitsos, Dionysios E.; Yi, Xing; Platt, Trevor; Racault, Marie-Fanny; Brewin, Robert J. W.; Pradhan, Yaswant; Papadopoulos, Vassilis P.; Sathyendranath, Shubha; Hoteit, Ibrahim

    2015-01-01

    Tropical ocean ecosystems are predicted to become warmer, more saline, and less fertile in a future Earth. The Red Sea, one of the warmest and most saline environments in the world, may afford insights into the function of the tropical ocean ecosystem in a changing planet. We show that the concentration of chlorophyll and the duration of the phytoplankton growing season in the Red Sea are controlled by the strength of the winter Arabian monsoon (through horizontal advection of fertile waters from the Indian Ocean). Furthermore, and contrary to expectation, in the last decade (1998-2010) the winter Red Sea phytoplankton biomass has increased by 75% during prolonged positive phases of the Multivariate El Niño-Southern Oscillation Index. A new mechanism is reported, revealing the synergy of monsoon and climate in regulating Red Sea greenness. © 2015 The Authors.

  6. Climate variations of Central Asia on orbital to millennial timescales.

    Science.gov (United States)

    Cheng, Hai; Spötl, Christoph; Breitenbach, Sebastian F M; Sinha, Ashish; Wassenburg, Jasper A; Jochum, Klaus Peter; Scholz, Denis; Li, Xianglei; Yi, Liang; Peng, Youbing; Lv, Yanbin; Zhang, Pingzhong; Votintseva, Antonina; Loginov, Vadim; Ning, Youfeng; Kathayat, Gayatri; Edwards, R Lawrence

    2016-11-11

    The extent to which climate variability in Central Asia is causally linked to large-scale changes in the Asian monsoon on varying timescales remains a longstanding question. Here we present precisely dated high-resolution speleothem oxygen-carbon isotope and trace element records of Central Asia's hydroclimate variability from Tonnel'naya cave, Uzbekistan, and Kesang cave, western China. On orbital timescales, the supra-regional climate variance, inferred from our oxygen isotope records, exhibits a precessional rhythm, punctuated by millennial-scale abrupt climate events, suggesting a close coupling with the Asian monsoon. However, the local hydroclimatic variability at both cave sites, inferred from carbon isotope and trace element records, shows climate variations that are distinctly different from their supra-regional modes. Particularly, hydroclimatic changes in both Tonnel'naya and Kesang areas during the Holocene lag behind the supra-regional climate variability by several thousand years. These observations may reconcile the apparent out-of-phase hydroclimatic variability, inferred from the Holocene lake proxy records, between Westerly Central Asia and Monsoon Asia.

  7. Online Time Series Analysis of Land Products over Asia Monsoon Region via Giovanni

    Science.gov (United States)

    Shen, Suhung; Leptoukh, Gregory G.; Gerasimov, Irina

    2011-01-01

    Time series analysis is critical to the study of land cover/land use changes and climate. Time series studies at local-to-regional scales require higher spatial resolution, such as 1km or less, data. MODIS land products of 250m to 1km resolution enable such studies. However, such MODIS land data files are distributed in 10ox10o tiles, due to large data volumes. Conducting a time series study requires downloading all tiles that include the study area for the time period of interest, and mosaicking the tiles spatially. This can be an extremely time-consuming process. In support of the Monsoon Asia Integrated Regional Study (MAIRS) program, NASA GES DISC (Goddard Earth Sciences Data and Information Services Center) has processed MODIS land products at 1 km resolution over the Asia monsoon region (0o-60oN, 60o-150oE) with a common data structure and format. The processed data have been integrated into the Giovanni system (Goddard Interactive Online Visualization ANd aNalysis Infrastructure) that enables users to explore, analyze, and download data over an area and time period of interest easily. Currently, the following regional MODIS land products are available in Giovanni: 8-day 1km land surface temperature and active fire, monthly 1km vegetation index, and yearly 0.05o, 500m land cover types. More data will be added in the near future. By combining atmospheric and oceanic data products in the Giovanni system, it is possible to do further analyses of environmental and climate changes associated with the land, ocean, and atmosphere. This presentation demonstrates exploring land products in the Giovanni system with sample case scenarios.

  8. Herbarium specimens, photographs, and field observations show Philadelphia area plants are responding to climate change.

    Science.gov (United States)

    Panchen, Zoe A; Primack, Richard B; Anisko, Tomasz; Lyons, Robert E

    2012-04-01

    The global climate is changing rapidly and is expected to continue changing in coming decades. Studying changes in plant flowering times during a historical period of warming temperatures gives us a way to examine the impacts of climate change and allows us to predict further changes in coming decades. The Greater Philadelphia region has a long and rich history of botanical study and documentation, with abundant herbarium specimens, field observations, and botanical photographs from the mid-1800s onward. These extensive records also provide an opportunity to validate methodologies employed by other climate change researchers at a different biogeographical area and with a different group of species. Data for 2539 flowering records from 1840 to 2010 were assessed to examine changes in flowering response over time and in relation to monthly minimum temperatures of 28 Piedmont species native to the Greater Philadelphia region. Regression analysis of the date of flowering with year or with temperature showed that, on average, the Greater Philadelphia species studied are flowering 16 d earlier over the 170-yr period and 2.7 d earlier per 1°C rise in monthly minimum temperature. Of the species studied, woody plants with short flowering duration are the best indicators of a warming climate. For monthly minimum temperatures, temperatures 1 or 2 mo prior to flowering are most significantly correlated with flowering time. Studies combining herbarium specimens, photographs, and field observations are an effective method for detecting the effects of climate change on flowering times.

  9. Simulation of Land-Cover Change in Taipei Metropolitan Area under Climate Change Impact

    International Nuclear Information System (INIS)

    Huang, Kuo-Ching; Huang, Thomas C C

    2014-01-01

    Climate change causes environment change and shows up on land covers. Through observing the change of land use, researchers can find out the trend and potential mechanism of the land cover change. Effective adaptation policies can affect pattern of land cover change and may decrease the risks of climate change impacts. By simulating land use dynamics with scenario settings, this paper attempts to explore the relationship between climate change and land-cover change through efficient adaptation polices. It involves spatial statistical model in estimating possibility of land-cover change, cellular automata model in modeling land-cover dynamics, and scenario analysis in response to adaptation polices. The results show that, without any control, the critical eco-areas, such as estuarine areas, will be destroyed and people may move to the vulnerable and important economic development areas. In the other hand, under the limited development condition for adaptation, people migration to peri-urban and critical eco-areas may be deterred

  10. Adaptive Effectiveness of Irrigated Area Expansion in Mitigating the Impacts of Climate Change on Crop Yields in Northern China

    Directory of Open Access Journals (Sweden)

    Tianyi Zhang

    2017-05-01

    Full Text Available To improve adaptive capacity and further strengthen the role of irrigation in mitigating climate change impacts, the Chinese government has planned to expand irrigated areas by 4.4% by the 2030s. Examining the adaptive potential of irrigated area expansion under climate change is therefore critical. Here, we assess the effects of irrigated area expansion on crop yields based on county-level data during 1980–2011 in northern China and estimate climate impacts under irrigated area scenarios in the 2030s. Based on regression analysis, there is a statistically significant effect of irrigated area expansion on reducing negative climate impacts. More irrigated areas indicate less heat and drought impacts. Irrigated area expansion will alleviate yield reduction by 0.7–0.8% in the future but associated yield benefits will still not compensate for greater adverse climate impacts. Yields are estimated to decrease by 4.0–6.5% under future climate conditions when an additional 4.4% of irrigated area is established, and no fundamental yield increase with an even further 10% or 15% expansion of irrigated area is predicted. This finding suggests that expected adverse climate change risks in the 2030s cannot be mitigated by expanding irrigated areas. A combination of this and other adaptation programs is needed to guarantee grain production under more serious drought stresses in the future.

  11. The Impact of Climate Change in Rainfall Erosivity Index on Humid Mudstone Area

    Science.gov (United States)

    Yang, Ci-Jian; Lin, Jiun-Chuan

    2017-04-01

    It has been quite often pointed out in many relevant studies that climate change may result in negative impacts on soil erosion. Then, humid mudstone area is highly susceptible to climate change. Taiwan has extreme erosion in badland area, with annual precipitation over 2000 mm/y which is a considerably 3 times higher than other badland areas around the world, and with around 9-13 cm/y in denudation rate. This is the reason why the Erren River, a badland dominated basin has the highest mean sediment yield in the world, over 105 t km2 y. This study aims to know how the climate change would affect soil erosion from the source in the Erren River catchment. Firstly, the data of hourly precipitation from 1992 to 2016 are used to establish the regression between rainfall erosivity index (R, one of component for USLE) and precipitation. Secondly, using the 10 climate change models (provide form IPCC AR5) simulates the changes of monthly precipitation in different scenario from 2017 to 2216, and then over 200 years prediction R values can be use to describe the tendency of soil erosion in the future. The results show that (1) the relationship between rainfall erosion index and precipitation has high correction (>0.85) during 1992-2016. (2) From 2017 to 2216, 7 scenarios show that annual rainfall erosion index will increase over 2-18%. In contrast, the others will decrease over 7-14%. Overall, the variations of annual rainfall erosion index fall in the range of -14 to 18%, but it is important to pay attention to the variation of annual rainfall erosion index in extreme years. These fall in the range of -34 to 239%. This explains the extremity of soil erosion will occur easily in the future. Keywords: Climate Change, Mudstone, Rainfall Erosivity Index, IPCC AR5

  12. Enhancement of vegetation-rainfall feedbacks on the Australian summer monsoon by the Madden-Julian Oscillation

    Science.gov (United States)

    Notaro, Michael

    2018-01-01

    A regional climate modeling analysis of the Australian monsoon system reveals a substantial modulation of vegetation-rainfall feedbacks by the Madden Julian Oscillation (MJO), both of which operate at similar sub-seasonal time scales, as evidence that the intensity of land-atmosphere interactions is sensitive to the background atmospheric state. Based on ensemble experiments with imposed modification of northern Australian leaf area index (LAI), the atmospheric responses to LAI anomalies are composited for negative and positive modes of the propagating MJO. In the regional climate model (RCM), northern Australian vegetation feedbacks are characterized by evapotranspiration (ET)-driven rainfall responses, with the moisture feedback mechanism dominating over albedo and roughness feedback mechanisms. During November-April, both Tropical Rainfall Measuring Mission and RCM data reveal MJO's pronounced influence on rainfall patterns across northern Australia, tropical Indian Ocean, Timor Sea, Arafura Sea, and Gulf of Carpentaria, with the MJO dominating over vegetation feedbacks in terms of regulating monsoon rainfall variability. Convectively-active MJO phases support an enhancement of positive vegetation feedbacks on monsoon rainfall. While the MJO imposes minimal regulation of ET responses to LAI anomalies, the vegetation feedback-induced responses in precipitable water, cloud water, and rainfall are greatly enhanced during convectively-active MJO phases over northern Australia, which are characterized by intense low-level convergence and efficient precipitable water conversion. The sub-seasonal response of vegetation-rainfall feedback intensity to the MJO is complex, with significant enhancement of rainfall responses to LAI anomalies in February during convectively-active MJO phases compared to minimal modulation by the MJO during prior and subsequent calendar months.

  13. Seasonal modulation of the Asian summer monsoon between the Medieval Warm Period and Little Ice Age: a multi model study

    Science.gov (United States)

    Kamae, Youichi; Kawana, Toshi; Oshiro, Megumi; Ueda, Hiroaki

    2017-12-01

    Instrumental and proxy records indicate remarkable global climate variability over the last millennium, influenced by solar irradiance, Earth's orbital parameters, volcanic eruptions and human activities. Numerical model simulations and proxy data suggest an enhanced Asian summer monsoon during the Medieval Warm Period (MWP) compared to the Little Ice Age (LIA). Using multiple climate model simulations, we show that anomalous seasonal insolation over the Northern Hemisphere due to a long cycle of orbital parameters results in a modulation of the Asian summer monsoon transition between the MWP and LIA. Ten climate model simulations prescribing historical radiative forcing that includes orbital parameters consistently reproduce an enhanced MWP Asian monsoon in late summer and a weakened monsoon in early summer. Weakened, then enhanced Northern Hemisphere insolation before and after June leads to a seasonally asymmetric temperature response over the Eurasian continent, resulting in a seasonal reversal of the signs of MWP-LIA anomalies in land-sea thermal contrast, atmospheric circulation, and rainfall from early to late summer. This seasonal asymmetry in monsoon response is consistently found among the different climate models and is reproduced by an idealized model simulation forced solely by orbital parameters. The results of this study indicate that slow variation in the Earth's orbital parameters contributes to centennial variability in the Asian monsoon transition.[Figure not available: see fulltext.

  14. Economic Impacts of Climate Change on Winter Tourism: Challenges for Ski Area Operators

    Science.gov (United States)

    Damm, A.; Köberl, J.; Prettenthaler, F.; Töglhofer, C.

    2012-04-01

    Increasing temperatures and snow scarce winter seasons pose a big challenge for the winter tourism industry. Changing natural snow reliability influences tourism demand and ski area operators are faced with an enhanced need of technical snow production. The goal of the present research work is to analyze the economic effects of technical snow production under future climate conditions. Snowmaking as an adaptation strategy to climate change impacts on the ski tourism industry is already taken into consideration in several studies from a scientific perspective concerning snowmaking potentials under future climate conditions and the impacts on ski season length (e.g. Scott et al. 2003; Scott & McBoyle 2007; Hennessy et al. 2008; Steiger 2010). A few studies considered economic aspects of technical snowmaking (e.g. Teich et al. 2007; Gonseth 2008). However, a detailed analysis of the costs and benefits of snowmaking under future climate and snow conditions based on sophisticated climate and snow models has not been carried out yet. The present study addresses the gap of knowledge concerning the economic profitability of prospective snowmaking requirements under future climate scenarios. We carry out a detailed cost-revenue analysis of snowmaking under current and future climate conditions for a case study site in Styria (Austria) using dynamic investment models. The starting point of all economic calculations is the daily demand for artificial snow that determines the requirements for additional snowmaking investments and additional operating costs. The demand for artificial snow is delivered by the snow cover model AMUNDSEN (see Strasser et al. 2011) and is driven by four climate scenarios. Apart from future climate conditions the profitability of snowmaking depends on changes in costs and visitor numbers. The results of a ski tourism demand model analyzing daily visitor numbers and their dependencies of prevailing weather conditions enter the cost-revenue analysis of

  15. Climatic data for the Cottonwood Lake area, Stutsman County, North Dakota 1982

    Science.gov (United States)

    Sturrock, A.M.; Hanson, B.A.; Scarborough, J.L.; Winter, T.C.

    1986-01-01

    Research on the hydrology of the Cottonwood Lake area, Stutsman County, North Dakota, includes study of evaporation. Presented here are those climatic data needed for energy-budget and mass-transfer evaporation studies, including: water-surface temperature, sediment temperature dry-bulb and wet-bulb air temperatures, vapor pressure at and above the water surface, wind speed, and short- and long-wave radiation. Data were collected at raft and land stations.

  16. Climatic data for the Cottonwood Lake area, Stutsman County, North Dakota, 1983

    Science.gov (United States)

    Sturrock, A.M.; Hanson, B.A.; Scarborough, J.L.; Winter, T.C.

    1987-01-01

    Research on the hydrology of the Cottonwood Lake area, Stutsman County, North Dakota, includes study of evaporation. Climatic data needed for energy-budget and mass-transfer evaporation studies that were collected during 1983 include water-surface temperature, sediment temperature, dry-bulb and wet-bulb air temperature, vapor pressure at and above the water surface, wind speed, and short-and long-wave radiation. Data are collected at raft and land stations. (USGS)

  17. Climate change in urban areas. Green and water storage in relation to soils

    International Nuclear Information System (INIS)

    Dirven-van Breemen, E.M.; Claessens, J.W.; Hollander, A.

    2011-08-01

    One of the possible effects of climate change in urban areas is an increased frequency of periods of extreme heat and extreme rainfall events. Public green areas provide shadow and therefore have a cooling effect during periods of extreme heat. Sufficient water storage capacity of the soil may reduce the overburdening of the public water system during extreme rainfall events. Governments do well by taking measures for climate-proofing of their towns. Also citizens may contribute to these climate issues. Governments and citizens should realize that investing in climate-proofing of their towns at this moment will pay off in the future. These are the outcomes of an inventory carried out by the National Institute for Public Health and the Environment, RIVM, ordered by the ministry of Infrastructure and the Environment. With measures for public green areas and water storage capacity local governments should link with other policy areas like infrastructure, public health, safety and sustainability. An example of more public green is a green infrastructure like parks and public gardens. An other advantage of public green is the unsealed soil; that is the soil not covered by roads, buildings, etc. The presence of unsealed soil increases the possibility for water infiltration. For favorable water storage local governments may construct wadis that prevent public water systems for being overburdened by extreme rainfall events. A wadi is a lowering of the surface level mostly covered with plants. During heavy rainfall the wadi is flooded, due to rainwater from the roofs of the surrounding buildings which drains away to the wadi. Citizens may construct green roofs or city gardens with unsealed soil. To promote this, subsidies for private initiatives are an additional boost. [nl

  18. Protected areas offer refuge from invasive species spreading under climate change

    Czech Academy of Sciences Publication Activity Database

    Gallardo, B.; Aldridge, D.; González-Moreno, P.; Pergl, Jan; Pizarro, M.; Pyšek, Petr; Thuiller, W.; Yesson, C.; Vila, M.

    2017-01-01

    Roč. 23, č. 12 (2017), s. 5331-5343 ISSN 1354-1013 R&D Projects: GA ČR GB14-36079G Grant - others:AV ČR(CZ) AP1002; COST(XE) TD1209 Program:Akademická prémie - Praemium Academiae; FA Institutional support: RVO:67985939 Keywords : climate change * protected areas * invasions Subject RIV: EH - Ecology, Behaviour OBOR OECD: Entomology Impact factor: 8.502, year: 2016

  19. Biodiversity and Phytosociological Studies of Upstream and Downstream Riparian Areas of Pakistan: Special Reference to Taunsa Wildlife Sanctuary and Keti Shah Forests

    International Nuclear Information System (INIS)

    Arfeen, R. Z.; Saleem, A.; Mirza, S. N.; Tayyab, H. M.; Akmal, M.; Afzal, O.

    2015-01-01

    Pakistan riparian zone mostly belongs to Sindh and Punjab provinces and prone to climatic problems and anthropogenic activities. The research was conduct to estimate and compare the structure and composition of riverine floral diversity in low riparian zone of River Indus. The data was collected from Keti Shah forest and Taunsa wildlife sanctuary. Total 14259 plants/individuals were recorded, which belong to 54 plant species with 18 different families. In Taunsa pre-monsoon survey, total 30 plant species were found with 4476 plants from 16 different families. In Taunsa post-monsoon survey total 3348 individuals were recorded from 20 plant species and 9 families. Similarly, in Keti Shah forest, total 3975 individual were recorded from 22 species and 11 families during the pre-monsoon season and 2460 plants were recorded in post-monsoon season, belonging to 16 species and 10 families. These species mostly belong to Fabaceae, Poaceae, Cyperaceae and Asclepiadaceae. Different phytosociological parameters indicate Tamarix dioca, Cynodon dactylon, Desmostachya bipinnata, Imperata cylindrica, Fimbristylis hispidula, Acacia nilotica, Phragmites karka, Tamarix sp. and Saccharum bengalense as dominant species. The biodiversity in upstream and downstream areas were rich in pre-monsoon season in comparison to post-monsoon season in surveyed areas. This study is useful for management of the area in the future as conservation strategies can be made through considering the adaptive tree species in future plantation and endangered species can be conserved. (author)

  20. Heavy Rainfall Associated with a Monsoon Depression in South China: Structure Analysis

    Institute of Scientific and Technical Information of China (English)

    JIANG Jianying; JIANG Jixi; BU Yalin; LIU Nianqing

    2008-01-01

    A heavy rainfall associated with the deepening of a monsoon depression happened in the summer of 2005.This process was first diagnostically analyzed and the 3D structure of the monsoon depression was discussed,then this structure was compared with those of the monsoon depression in South Asia and the low vortex in the Meiyu front. The results showed that the heavy rainfall directly resulted from a monsoon depression in South China, and the large-scale environment provided a favorable background for the deepening of the monsoon depression. The 3D structure of the monsoon depression was as follows. In the horizontal direction,there existed a convective cloud band to the south of the monsoon depression, which lay in a convectively instable area, with a relatively strong ascending motion in the mid and low levels of the troposphere, and the ascending motion matched well with a moist tongue, a convergence area, and a band of positive vorticity in the mid and low levels of the troposphere. In the vertical direction, the depression had an obviously cyclonic circulation in the mid and low levels of the troposphere, but no circulation from above 300 hPa. The monsoon depression corresponded to convergence and positive vorticity in the low levels, but to divergence and negative vortieity in the upper levels. The upward draft of the depression could reach the upper levels of the troposphere in the west of the depression, while the descending motion lay in the east. There was a low-level jet to the south of the depression, while the upper-level jet was not obvious. The depression was vertically warm in the upper levels and cold in the low levels, and the axis of the depression tilted southeastward with height, whose characteristics were different not only from the monsoon depression in South Asia but also from the low vortex in the Meiyu front.

  1. The northwestern Indian Ocean during the monsoons of 1979: distribution, abundance, and feeding of zooplankton

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.L.

    1982-01-01

    Upwelling induced by the separation of the Somali Current from the coast of east Africa is associated with low surface temperatures, high concentrations of nitrate, and blooms of phytoplankton. Coefficients of concordance, based upon 17 taxa of zooplankton collected at 33 stations in the southwest monsoon and 15 stations in the northeast monsoon, were consistently larger for the southwest monsoon and indicative of a general response of the zooplankton in the northwestern Indian Ocean. The largest coefficients of concordance in the southwest monsoon were among adult females of Paracalanus denudatus, Paracalanus parvus, and Paracalanus aculeatus and of Calanoides carinatus and Eucalanus spp. Coefficients of concordance among copepodids of six taxa had a trend similar to adult females in the southwest monsoon. During the southwest monsoon, total biomass of zooplankton was significantly greater within areas of upwelling than outside; adult females and copepodids of C. carinatus and Eucalanus spp. were significantly more abundant within the upwelling regions, along with adult females of Clausocalanus furcatus and Clausocalanus minor. The upwelling regions, which are associated with a reproductively active population of the large-bodied C. carinatus, are the primary features affecting distributions of zooplankton during the southwest monsoon and the main difference between monsoons. The ontogenetic migration of C. carinatus is essentially an annual life-history strategy and therefore on the same temporal scale as the reversals in the monsoonal winds and associated upwelling. The ability of C. carinatus to ingest readily the diatoms that dominate the upwelling regions and to store lipid is crucial to its dominance of the areas of upwelling both in numbers and biomass.

  2. Climate Change and its Impacts on Tourism and Livelihood in Manaslu Conservation Area, Nepal

    Science.gov (United States)

    K C, A.

    2017-12-01

    The Hindukush Himalayan region including Nepal, a country reliant on tourism, is particularly sensitive to climate change. It had impact on different sectors of the environment including tourism and livelihood. There are very few researches focused on tourism, livelihood and climate change in Nepal. The present research assesses the impact of climate change on tourism and livelihood in the Manaslu Conservation Area (MCA) of Nepal. In this study, the empirical data collected at the field was complemented by secondary data on climate and tourism. For primary data collection, seventy-six households were interviewed followed by three focus group discussions and five key informant interviews. Correlation, regression and graphical analysis was carried out for the presentation of data. Local people perceived that temperature and rainfall have been increasing in the study site as a result of climate change. Change in usual pattern of temperature and rainfall had affected tourism sector. Socioeconomic variables such as marital status, size of household, education and landholding status had positive effect on tourism participation while livestock-holding status and occupation of the household had negative effect on tourism participation. Number of visitors is increasing in MCA in recent years, and tourism participation is helping local people to earn more money and improve their living standard. In response to gradually warming temperature and decreasing snowfall, there seems an urgent need for tourism promotional activities in the study area. Also awareness and education related to tourism, gender empowerment of women, advertisement and publicity on tourism promotion, adequate subsidy and training on ecotourism and skill development trainings on handicraft are recommended.

  3. Regional impact of climate on Japanese encephalitis in areas located near the three gorges dam.

    Directory of Open Access Journals (Sweden)

    Yuntao Bai

    Full Text Available BACKGROUND: In this study, we aim to identify key climatic factors that are associated with the transmission of Japanese encephalitis virus in areas located near the Three Gorges Dam, between 1997 and 2008. METHODS: We identified three geographical regions of Chongqing, based on their distance from the Three Gorges Dam. Collectively, the three regions consisted of 12 districts from which study information was collected. Zero-Inflated Poisson Regression models were run to identify key climatic factors of the transmission of Japanese encephalitis virus for both the whole study area and for each individual region; linear regression models were conducted to examine the fluctuation of climatic variables over time during the construction of the Three Gorges Dam. RESULTS: Between 1997 and 2008, the incidence of Japanese encephalitis decreased throughout the entire city of Chongqing, with noticeable variations taking place in 2000, 2001 and 2006. The eastern region, which is closest to the Three Gorges Dam, suffered the highest incidence of Japanese encephalitis, while the western region experienced the lowest incidence. Linear regression models revealed that there were seasonal fluctuations of climatic variables during this period. Zero-Inflated Poisson Regression models indicated a significant positive association between temperature (with a lag of 1 and 3 months and Japanese encephalitis incidence, and a significant negative association between rainfall (with a lag of 0 and 4 months and Japanese encephalitis incidence. CONCLUSION: The spatial and temporal trends of Japanese encephalitis incidence that occurred in the City of Chongqing were associated with temperature and rainfall. Seasonal fluctuations of climatic variables during this period were also observed. Additional studies that focus on long-term data collection are needed to validate the findings of this study and to further explore the effects of the Three Gorges Dam on Japanese

  4. Distributional patterns of anemophilous tree pollen indicating the pathways of Indian monsoon through Qinghai–Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    Zhi-Yong Zhang

    2017-10-01

    Full Text Available The distribution pattern of vegetation on Qinghai–Tibetan Plateau is fundamentally influenced by the plateau climate, which is mainly controlled by Indian monsoon during summer. The long distance transportation of pollen (mostly anemophilous taxa produced by trees on the plateau has been recorded by modern pollen samples in previous studies, and hypothesized to be a good indicator of monsoon dynamics. Here we use 270 surface pollen samples from Qinghai–Tibetan Plateau to test the distribution patterns of the anemophilous tree pollen. Meanwhile factors related to Indian monsoon affecting pollen transportation are simulated and analyzed. Results show that depositional patterns of anemophilous tree pollen, especially Abies, Pinus, Quercus and Betula are completely controlled by the pathways of Indian monsoon. This is reflected by climatic indicators of the atmospheric pressure pattern over June–July–August, by the precipitation pattern over June–July–August and by the topographic feature of the plateau. The spatial interpolation of thin plate spline results also display two depositional centers (ca. 30°N, 95°E and 30°N, 105°E of the anemophilous tree pollen. In contrast to previous conclusion that pollen distributional pattern is determined by mean annual precipitation, we argue that Indian monsoon is the essential controller because of the synchronization between timing of monsoon wind and timing of plants flowering. Our finding strongly suggests that distributional pattern of anemophilous tree pollen on the plateau is a good proxy of Indian monsoon.

  5. Climate adaptation in NVE's areas of responsibility - Strategy 2010 - 2014; Klimatilpasning innen NVEs ansvarsomraader - Strategi 2010 - 2014

    Energy Technology Data Exchange (ETDEWEB)

    Hamarsland, Arne T. (ed.)

    2010-09-15

    NVE has developed a comprehensive climate change strategies within their areas of responsibility. There is a systematic review of how a future climate change will affect NVE management areas; how to meet challenges, vulnerabilities, opportunities and proposals for adaptation measures. Climate adaptation is a dynamic process. It is therefore necessary to follow up the work continuously and correct direction at regular intervals. Climate change adaptation strategy of adaptation measures is a foundation and a direction sensor in NVE's business planning. (AG)

  6. Regional trends in early-monsoon rainfall over Vietnam and CCSM4 attribution

    Science.gov (United States)

    Li, R.; Wang, S. S.-Y.; Gillies, R. R.; Buckley, B. M.; Yoon, J.-H.; Cho, C.

    2018-04-01

    The analysis of precipitation trends for Vietnam revealed that early-monsoon precipitation has increased over the past three decades but to varying degrees over the northern, central and southern portions of the country. Upon investigation, it was found that the change in early-monsoon precipitation is associated with changes in the low-level cyclonic airflow over the South China Sea and Indochina that is embedded in the large-scale atmospheric circulation associated with a "La Niña-like" anomalous sea surface temperature pattern with warming in the western Pacific and Indian Oceans and cooling in the eastern Pacific. The Community Climate System Model version 4 (CCSM4) was subsequently used for an attribution analysis. Over northern Vietnam an early-monsoon increase in precipitation is attributed to changes in both greenhouse gases and natural forcing. For central Vietnam, the observed increase in early-monsoon precipitation is reproduced by the simulation forced with greenhouse gases. However, over southern Vietnam the early-monsoon precipitation increase is less definitive where aerosols were seen to be preponderant but natural forcing through the role of the Interdecadal Pacific Oscillation may well be a factor that is not resolved by CCSM4. Increased early-monsoonal precipitation over the coastal lowland and deltas has the potential to amplify economic and human losses.

  7. A vigorous Mesoamerican monsoon during the Last Glacial Maximum driven by orbital and oceanic forcing

    Science.gov (United States)

    Lachniet, M. S.; Asmerom, Y.; Bernal, J. P.; Polyak, V.; Vazquez-Selem, L. V.

    2012-12-01

    The external forcings on global monsoon strength include summer orbital insolation and ocean circulation changes, both of which are key control knobs on Earth's climate. However, few records of the North American Monsoon (NAM) are available to test its sensitivity to variations in the precession-dominated insolation signal and Atlantic Meridional Overturning Circulation (AMOC) for the Last Glacial Maximum (LGM; 21 ± 3 cal ka BP) and deglacial periods. In particular, well-dated and high-resolution records from the southern sector of the NAM, referred to informally as the Mesoamerican monsoon to distinguish it from the more northerly 'core' NAM, are needed to better elucidate paleoclimate change in North America. Here, we present a 22 ka (ka = kilo years) rainfall history from absolutely-dated speleothems from tropical southwestern Mexico that documents a vigorous LGM summer monsoon, in contradiction to previous interpretations, and that the monsoon collapsed during the Heinrich stadial 1 and Younger Dryas cold events. We conclude that a strong Mesoamerican monsoon requires both a large ocean-to-land temperature contrast, driven as today by summer insolation, and a proximal latitudinal position of the Intertropical Convergence Zone, forced by active AMOC.

  8. Mineralogical evidence of reduced East Asian summer monsoon rainfall on the Chinese loess plateau during the early Pleistocene interglacials

    Science.gov (United States)

    Meng, Xianqiang; Liu, Lianwen; Wang, Xingchen T.; Balsam, William; Chen, Jun; Ji, Junfeng

    2018-03-01

    The East Asian summer monsoon (EASM) is an important component of the global climate system. A better understanding of EASM rainfall variability in the past can help constrain climate models and better predict the response of EASM to ongoing global warming. The warm early Pleistocene, a potential analog of future climate, is an important period to study EASM dynamics. However, existing monsoon proxies for reconstruction of EASM rainfall during the early Pleistocene fail to disentangle monsoon rainfall changes from temperature variations, complicating the comparison of these monsoon records with climate models. Here, we present three 2.6 million-year-long EASM rainfall records from the Chinese Loess Plateau (CLP) based on carbonate dissolution, a novel proxy for rainfall intensity. These records show that the interglacial rainfall on the CLP was lower during the early Pleistocene and then gradually increased with global cooling during the middle and late Pleistocene. These results are contrary to previous suggestions that a warmer climate leads to higher monsoon rainfall on tectonic timescales. We propose that the lower interglacial EASM rainfall during the early Pleistocene was caused by reduced sea surface temperature gradients across the equatorial Pacific, providing a testable hypothesis for climate models.

  9. An Assessment of Monsoon Triggered Landslides in Western Nepal

    Science.gov (United States)

    Sudan Acharya, Madhu

    2010-05-01

    Due to heavy monsoon rain, rugged topography and very young mountains, frequent slope failures and soil erosion are very common in Nepal but in most of cases the natural slopes are disturbed by men to construct a road through it and the situation further aggravated by the Monsoon rain. Summer usually tests the disaster response capacity of Nepal, when the monsoons trigger water induced disasters. This year Nepal's Western regions were most severely affected by floods and landslides. Every year, sadly, it is the same story of mostly poor people living in remote villages succumbing to landslides and flooding and those who survive facing hardships brought on by the disaster. The tail end of the monsoon in October has triggered flood and landslides in Nepal which affected a total of 14 districts in the mid and far-west regions, of which Kailali, Bardiya, Banke, Dadeldhura, Accham and Kanchapur district are most affected. The affected areas are geographically scattered and remote, and are therefore difficult to access. In this year (2009), flood and landslides have claimed 62 lives, affecting more than 152,000 individuals from 27,000 families. More than 4,000 families are displaced and are taking shelter in schools, open space and forest areas with no protection from the external elements. In the above context the prevention and mitigation measures for landslides is a great challenge for Nepal. Nepal has been investing its huge amount of resources to stabilize landslides and roadside slope failures, still then it has become unmanageable during Monsoon time. Considering the above facts, an assessment of landslides which were occurred during the Monsoon (July-October 2009), along Khodpe - Jhota - Chainpur road in far western region of Nepal has been carried out based on the field observation of various landslides. The paper presents the causes and mechanisms of failures of different landslides which are mostly triggered by Monsoon rain. It also suggests some low cost

  10. Climate change and protection: Recent experiences within planning of the area of cultural and natural heritage

    Directory of Open Access Journals (Sweden)

    Crnčević Tijana

    2015-01-01

    Full Text Available The aim of the paper is to provide an insight into the current legal and other regulatory frameworks that introduces problems of climate change into planning practice of natural and cultural heritage, with special emphasis on the situation in the Republic of Serbia. Further, an overview of the selected case studies of natural and cultural heritage from the UNESCO World Heritage List for which were done studies of the impacts of climate change is included. The results indicate that the legal frameworks as well as actual practice are promoting the development of the ecological networks (the network of areas NATURA 2000 and landscape protection. This applies also to the planning practice in Serbia, where the planning of ecological corridors, habitat networking and other measures, provide responses to climate change. One of the conclusions of this paper is pointing out the necessity of increasing the level of protection of natural and cultural heritage within preserving the authenticity and improving flexibility or adaptability to climate change.

  11. Signals of Climate Change in Butterfly Communities in a Mediterranean Protected Area

    Science.gov (United States)

    Zografou, Konstantina; Kati, Vassiliki; Grill, Andrea; Wilson, Robert J.; Tzirkalli, Elli; Pamperis, Lazaros N.; Halley, John M.

    2014-01-01

    The European protected-area network will cease to be efficient for biodiversity conservation, particularly in the Mediterranean region, if species are driven out of protected areas by climate warming. Yet, no empirical evidence of how climate change influences ecological communities in Mediterranean nature reserves really exists. Here, we examine long-term (1998–2011/2012) and short-term (2011–2012) changes in the butterfly fauna of Dadia National Park (Greece) by revisiting 21 and 18 transects in 2011 and 2012 respectively, that were initially surveyed in 1998. We evaluate the temperature trend for the study area for a 22-year-period (1990–2012) in which all three butterfly surveys are included. We also assess changes in community composition and species richness in butterfly communities using information on (a) species’ elevational distributions in Greece and (b) Community Temperature Index (calculated from the average temperature of species' geographical ranges in Europe, weighted by species' abundance per transect and year). Despite the protected status of Dadia NP and the subsequent stability of land use regimes, we found a marked change in butterfly community composition over a 13 year period, concomitant with an increase of annual average temperature of 0.95°C. Our analysis gave no evidence of significant year-to-year (2011–2012) variability in butterfly community composition, suggesting that the community composition change we recorded is likely the consequence of long-term environmental change, such as climate warming. We observe an increased abundance of low-elevation species whereas species mainly occurring at higher elevations in the region declined. The Community Temperature Index was found to increase in all habitats except agricultural areas. If equivalent changes occur in other protected areas and taxonomic groups across Mediterranean Europe, new conservation options and approaches for increasing species’ resilience may have to be

  12. Signals of climate change in butterfly communities in a Mediterranean protected area.

    Science.gov (United States)

    Zografou, Konstantina; Kati, Vassiliki; Grill, Andrea; Wilson, Robert J; Tzirkalli, Elli; Pamperis, Lazaros N; Halley, John M

    2014-01-01

    The European protected-area network will cease to be efficient for biodiversity conservation, particularly in the Mediterranean region, if species are driven out of protected areas by climate warming. Yet, no empirical evidence of how climate change influences ecological communities in Mediterranean nature reserves really exists. Here, we examine long-term (1998-2011/2012) and short-term (2011-2012) changes in the butterfly fauna of Dadia National Park (Greece) by revisiting 21 and 18 transects in 2011 and 2012 respectively, that were initially surveyed in 1998. We evaluate the temperature trend for the study area for a 22-year-period (1990-2012) in which all three butterfly surveys are included. We also assess changes in community composition and species richness in butterfly communities using information on (a) species' elevational distributions in Greece and (b) Community Temperature Index (calculated from the average temperature of species' geographical ranges in Europe, weighted by species' abundance per transect and year). Despite the protected status of Dadia NP and the subsequent stability of land use regimes, we found a marked change in butterfly community composition over a 13 year period, concomitant with an increase of annual average temperature of 0.95°C. Our analysis gave no evidence of significant year-to-year (2011-2012) variability in butterfly community composition, suggesting that the community composition change we recorded is likely the consequence of long-term environmental change, such as climate warming. We observe an increased abundance of low-elevation species whereas species mainly occurring at higher elevations in the region declined. The Community Temperature Index was found to increase in all habitats except agricultural areas. If equivalent changes occur in other protected areas and taxonomic groups across Mediterranean Europe, new conservation options and approaches for increasing species' resilience may have to be devised.

  13. Signals of climate change in butterfly communities in a Mediterranean protected area.

    Directory of Open Access Journals (Sweden)

    Konstantina Zografou

    Full Text Available The European protected-area network will cease to be efficient for biodiversity conservation, particularly in the Mediterranean region, if species are driven out of protected areas by climate warming. Yet, no empirical evidence of how climate change influences ecological communities in Mediterranean nature reserves really exists. Here, we examine long-term (1998-2011/2012 and short-term (2011-2012 changes in the butterfly fauna of Dadia National Park (Greece by revisiting 21 and 18 transects in 2011 and 2012 respectively, that were initially surveyed in 1998. We evaluate the temperature trend for the study area for a 22-year-period (1990-2012 in which all three butterfly surveys are included. We also assess changes in community composition and species richness in butterfly communities using information on (a species' elevational distributions in Greece and (b Community Temperature Index (calculated from the average temperature of species' geographical ranges in Europe, weighted by species' abundance per transect and year. Despite the protected status of Dadia NP and the subsequent stability of land use regimes, we found a marked change in butterfly community composition over a 13 year period, concomitant with an increase of annual average temperature of 0.95°C. Our analysis gave no evidence of significant year-to-year (2011-2012 variability in butterfly community composition, suggesting that the community composition change we recorded is likely the consequence of long-term environmental change, such as climate warming. We observe an increased abundance of low-elevation species whereas species mainly occurring at higher elevations in the region declined. The Community Temperature Index was found to increase in all habitats except agricultural areas. If equivalent changes occur in other protected areas and taxonomic groups across Mediterranean Europe, new conservation options and approaches for increasing species' resilience may have to be

  14. Monsoonal response to mid-holocene orbital forcing in a high resolution GCM

    Directory of Open Access Journals (Sweden)

    J. H. C. Bosmans

    2012-04-01

    Full Text Available In this study, we use a sophisticated high-resolution atmosphere-ocean coupled climate model, EC-Earth, to investigate the effect of Mid-Holocene orbital forcing on summer monsoons on both hemispheres. During the Mid-Holocene (6 ka, there was more summer insolation on the Northern Hemisphere than today, which intensified the meridional temperature and pressure gradients. Over North Africa, monsoonal precipitation is intensified through increased landward monsoon winds and moisture advection as well as decreased moisture convergence over the oceans and more convergence over land compared to the pre-industrial simulation. Precipitation also extends further north as the ITCZ shifts northward in response to the stronger poleward gradient of insolation. This increase and poleward extent is stronger than in most previous ocean-atmosphere GCM simulations. In north-westernmost Africa, precipitation extends up to 35° N. Over tropical Africa, internal feedbacks completely overcome the direct warming effect of increased insolation. We also find a weakened African Easterly Jet. Over Asia, monsoonal precipitation during the Mid-Holocene is increased as well, but the response is different than over North-Africa. There is more convection over land at the expense of convection over the ocean, but precipitation does not extend further northward, monsoon winds over the ocean are weaker and the surrounding ocean does not provide more moisture. On the Southern Hemisphere, summer insolation and the poleward insolation gradient were weaker during the Mid-Holocene, resulting in a reduced South American monsoon through decreased monsoon winds and less convection, as well as an equatorward shift in the ITCZ. This study corroborates the findings of paleodata research as well as previous model studies, while giving a more detailed account of Mid-Holocene monsoons.

  15. Characteristics of monsoonal circulation over the western Pacific

    Energy Technology Data Exchange (ETDEWEB)

    Shen, J; Chen, E

    1980-01-01

    In this article the meteorological observations on ships four times daily in the area between 0 to 46/sup 0/N, 90 to 155/sup 0/E has been utilized. The grid 2 x 2 degrees along coastal waters, and 5 x 5 degrees over the open sea have been used. Here the monsoon currents over the western Pacific are calculated and analyzed and a brief discussion is given. The following three criteria were obtained: (1) The monsoon current over the western Pacific between winter and summer changed almost in opposite directions with April and October being the transitional months. In general the wind direction change from summer to winter went from the coastal waters to the open sea. (2) After the discussion about the duration and the prevailing wind directions, the following was determined: during the winter monsoon period, the 25/sup 0/N latitudinal line may be regarded as the boundary from October to March when the winter wind directions inclined N (NW or N) to the north of that line; but to the south of it NE winds prevailed. However, the durations were quite different in different regions, ranging from five to nine months. Owing to the topographic influence of the Taiwan Strait, the duration of the NE wind lasted nine months. The 25/sup 0/N line may also be applied for summer monsoons; over the eastern open ocean from the Gulf of the Bohai Sea and the Japanese islands the southerly winds lasted about nine months, but in the Taiwan Strait they lasted only two months. (3) During the winter monsoon period, the region of strong winds which encircled the continent was over the open ocean to the east of the Japanese islands and the Philippines. However, it was not as near to the shore line as in the winter season, and the frequency of strong winds was somewhat more on the southern side of the 25/sup 0/N line.

  16. Developing a Climate-Induced Social Vulnerability Index for Urban Areas: A Case Study of East Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    Omitaomu, Olufemi A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Carvalhaes, Thomaz M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-09-01

    Census American Community Survey 2008-2012 data are used to construct a spatially explicit Climate-Induced Social Vulnerability Index (CSVI) for the East Tennessee area. This CSVI is a combination of a Social Vulnerability Index (SVI) and a Climate Index. A method is replicated and adapted to derive a custom SVI by Census tract for the counties participating in the East Tennessee Index, and a Climate Index is developed for the same area based on indicators for climate hazards. The resulting datasets are exported as a raster to be integrated and combined within the Urban Climate Adaptation Tool (Urban-CAT) to act as an indicator for communities which may be differentially vulnerable to changes in climate. Results for the SVI are mapped separately from the complete CSVI in this document as results for the latter are in development.

  17. Monsoon and primary acute angle closure in malaysia.

    Science.gov (United States)

    Ch'ng, T W; Mosavi, S A A; Noor Azimah, A A; Azlan, N Z; Azhany, Y; Liza-Sharmini, A T

    2013-10-01

    Acute angle closure (AAC) without prompt treatment may lead to optic neuropathy. Environmental factor such as climate change may precipitate pupillary block, the possible mechanism of AAC. To determine the association of northeast monsoon and incidence of AAC in Malaysia. A retrospective study was conducted on AAC patients admitted to two main tertiary hospitals in Kelantan, Malaysia between January 2001 and December 2011. The cumulative number of rainy day, amount of rain, mean cloud cover and 24 hours mean humidity at the estimated day of attack were obtained from the Department of Meteorology, Malaysia. A total 73 cases of AAC were admitted with mean duration of 4.1SD 2.0 days. More than half have previous history of possibility of AAC. There was higher incidence of AAC during the northeast monsoon (October to March). There was also significant correlation of number of rainy day (r=0.718, pclimate as the potential risk factor. Prompt treatment to arrest pupillary block and reduction of the intraocular pressure is important to prevent potential glaucomatous damage. Public awareness of AAC and accessibility to treatment should be part of preparation to face the effect of northeast monsoon.

  18. Application of Social Vulnerability Indicators to Climate Change for the Southwest Coastal Areas of Taiwan

    Directory of Open Access Journals (Sweden)

    Chin-Cheng Wu

    2016-12-01

    Full Text Available The impact of climate change on the coastal zones of Taiwan not only affects the marine environment, ecology, and human communities whose economies rely heavily on marine activities, but also the sustainable development of national economics. The southwest coast is known as the area most vulnerable to climate change; therefore, this study aims to develop indicators to assess social vulnerability in this area of Taiwan using the three dimensions of susceptibility, resistance, and resilience. The modified Delphi method was used to develop nine criteria and 26 indexes in the evaluation, and the analytic hierarchy process method was employed to evaluate the weight of each indicator based on the perspectives of experts collected through questionnaire surveys. The results provide important information pertaining to the vulnerability of the most susceptive regions, the lowest-resistance areas, and the least resilient townships on the southwest coast. The most socially vulnerable areas are plotted based on the present analysis. Experts can consider the vulnerability map provided here when developing adaptation policies. It should be kept in mind that improving the capacities of resistance and resilience is more important than reducing susceptibility in Taiwan.

  19. An integrated method for assessing climate-related risks and adaptation alternatives in urban areas

    Directory of Open Access Journals (Sweden)

    Yvonne Andersson-Sköld

    2015-01-01

    Full Text Available The urban environment is a complex structure with interlinked social, ecological and technical structures. Global warming is expected to have a broad variety of impacts, which will add to the complexity. Climate changes will force adaptation, to reduce climate-related risks. Adaptation measures can address one aspect at the time, or aim for a holistic approach to avoid maladaptation. This paper presents a systematic, integrated approach for assessing alternatives for reducing the risks of heat waves, flooding and air pollution in urban settings, with the aim of reducing the risk of maladaptation. The study includes strategies covering different spatial scales, and both the current climate situation and the climate predicted under climate change scenarios. The adaptation strategies investigated included increasing vegetation; selecting density, height and colour of buildings; and retreat or resist (defend against sea-level rise. Their effectiveness was assessed with regard to not only flooding, heat stress and air quality but also with regard to resource use, emissions to air (incl. GHG, soil and water, and people’s perceptions and vulnerability. The effectiveness of the strategies were ranked on a common scale (from −3 to 3 in an integrated assessment. Integrated assessments are recommended, as they help identify the most sustainable solutions, but to reduce the risk of maladaptation they require experts from a variety of disciplines. The most generally applicable recommendation, derived from the integrated assessment here, taking into account both expertise from different municipal departments, literature surveys, life cycle assessments and publics perceptions, is to increase the urban greenery, as it contributes to several positive aspects such as heat stress mitigation, air quality improvement, effective storm-water and flood-risk management, and it has several positive social impacts. The most favourable alternative was compact, mid

  20. 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

    The meteorological measurements at high-elevations of the Himalayan range are scarce due to the harsh conditions of these environments which limit the suitable maintenance of weather stations. As a consequence, the meager knowledge on how the climate is changed in the last decades at Himalayan high-elevations sets a serious limit upon the interpretation of relationships between causes and recent observed effects on the cryosphere. Although the glaciers masses reduction in Himalaya is currently sufficiently well described, how changes in climate drivers (precipitation and temperature) have influenced the melting and shrinkage processes are less clear. Consequently, the uncertainty related to the recent past amplifies when future forecasts are done, both for climate and impacts. In this context, a substantial body of research has already demonstrated the high sensitivity of lakes and ponds to climate. Some climate-related signals are highly visible and easily measurable in lakes. For example, climate-driven fluctuations in lake surface area have been observed in many remote sites. On interior Tibetan Plateau the lake growth since the late 1990s is mainly attributed to increased regional precipitation and weakened evaporation. Differently, other authors attribute at the observed increases of lake surfaces at the enhanced glacier melting. In our opinion these divergences found in literature are due to the type of glacial lakes considered in the study and in particular their relationship with glaciers. In general, in Himalaya three types of glacial lakes can be distinguished: (i) lakes that are not directly connected with glaciers, but that may have a glacier located in their basin (unconnected glacial lakes); (ii) supraglacial lakes, which develop on the surface of the glacier downstream; or (iii) proglacial lakes, which are moraine-dammed lakes that are in contact with the glacier front. Some of these lakes store large quantities of water and are susceptible to GLOFs

  1. The Neolithization of Northern Black Sea area in the context of climate changes

    Directory of Open Access Journals (Sweden)

    Nadezhda Kotova

    2009-12-01

    Full Text Available The neolithisation of the Pontic steppe was a long process, with four stages which were associated with climate changes. It began c. 7500 calBC, with early animal husbandry in the western Azov Sea area. The beginning of the second stage was connected with an arid climate (7000–6900 calBC and the origin of the Rakushechny Yar culture in the Lower Don region. The third stage (6500–6300 calBC occurred during a humid period. Besides animal husbandry, the steppe population borrowed the first pottery from the Rakushechny Yar culture. The fourth phase (6300–6000 calBC was connected with extreme aridity and the neolithisation of the modern forest-steppe and forest zones of Ukraine and Russia.

  2. Study of climate change related to deforestation in the Xishuangbanna area, Yunnan, China

    International Nuclear Information System (INIS)

    Chungcheng Li; Cong Lai

    1991-01-01

    The analysis of the results of deforestation and the meteorological data of the Xinshuangbanna region of China shows that there are possible relations between the deforestation and climate change. With the forest area decreased by 33% during the past 30 years, the climate of this region has also been changed. The annual mean temperature has been increased by 0.7C, of which the increase is 0.97C in the dry season and 0.53C in the wet season. Together with the annual temperature increase the temperature variations have also been increased, which has resulted in more frequent low temperature damage to the local plantation agriculture. The relative humidity decreased by 3% annually; and the annual precipitation also decreased, with a decrease in the wet season of 6.8% and an increase in the dry season of 20.8%

  3. Analysis of Compound Water Hazard in Coastal Urbanized Areas under the Future Climate

    Science.gov (United States)

    Shibuo, Y.; Taniguchi, K.; Sanuki, H.; Yoshimura, K.; Lee, S.; Tajima, Y.; Koike, T.; Furumai, H.; Sato, S.

    2017-12-01

    Several studies indicate the increased frequency and magnitude of heavy rainfalls as well as the sea level rise under the future climate, which implies that coastal low-lying urbanized areas may experience increased risk against flooding. In such areas, where river discharge, tidal fluctuation, and city drainage networks altogether influence urban inundation, it is necessary to consider their potential interference to understand the effect of compound water hazard. For instance, pump stations cannot pump out storm water when the river water level is high, and in the meantime the river water level shall increase when it receives pumped water from cities. At the further downstream, as the tidal fluctuation regulates the water levels in the river, it will also affect the functionality of pump stations and possible inundation from rivers. In this study, we estimate compound water hazard in the coastal low-lying urbanized areas of the Tsurumi river basin under the future climate. We developed the seamlessly integrated river, sewerage, and coastal hydraulic model that can simulate river water levels, water flow in sewerage network, and inundation from the rivers and/or the coast to address the potential interference issue. As a forcing, the pseudo global warming method, which applies the changes in GCM anomaly to re-analysis data, is employed to produce ensemble typhoons to drive the seamlessly integrated model. The results show that heavy rainfalls caused by the observed typhoon generally become stronger under the pseudo global climate condition. It also suggests that the coastal low-lying areas become extensively inundated if the onset of river flooding and storm surge coincides.

  4. Analysis and mapping of present and future drought conditions over Greek areas with different climate conditions

    Science.gov (United States)

    Paparrizos, Spyridon; Maris, Fotios; Weiler, Markus; Matzarakis, Andreas

    2018-01-01

    Estimation of drought in a certain temporal and spatial scale is crucial in climate change studies. The current study targets on three agricultural areas widespread in Greece, Ardas River Basin in Northeastern Greece, Sperchios River Basin in Central Greece, and Geropotamos River Basin in Crete Island in South Greece that are characterized by diverse climates as they are located in various regions. The objective is to assess the spatiotemporal variation of drought conditions prevailing in these areas. The Standardized Precipitation Index (SPI) was used to identify and assess the present and future drought conditions. Future simulated data were derived from a number of Regional Climatic Models (RCMs) from the ENSEMBLES European Project. The analysis was performed for the future periods of 2021-2050 and 2071-2100, implementing A1B and B1 scenarios. The spatial analysis of the drought conditions was performed using a combined downscaling technique and the Ordinary Kriging. The Mann-Kendall test was implemented for trend investigation. During both periods and scenarios, drought conditions will tend to be more severe in the upcoming years. The decrease of the SPI values in the Sperchios River Basin is expected to be the strongest, as it is the only study area that will show a negative balance (in SPI values), regarding the drought conditions. For the Ardas and the Geropotamos River Basins, a great increase of the drought conditions will occur during the 2021-2050 period, while for 2071-2100 period, the decrease will continue but it will be tempered. Nevertheless, the situation in all study areas according to the SPI classification is characterized as "Near-normal", in terms of drought conditions.

  5. Variations of the Indian summer monsoon over the Mio-Pliocene recorded in the Bengal Fan (IODP Exp354): implications for the evolution of the terrestrial biosphere.

    Science.gov (United States)

    Galy, Valier; Feakins, Sarah; Karkabi, Elias; Ponton, Camilo; Galy, Albert; France-Lanord, Christian

    2017-04-01

    A pressing challenge in climate research is understanding the temporal evolution of the Indian monsoon system; its response to global and regional climatic controls (including warming); as well as implications in terms of vegetation (C4 expansion), erosion of the Himalaya and carbon sequestration in the Bengal Fan. Studies on climate dynamics have recently offered new insights into the mechanistic controls on the monsoon: the tectonic boundary of the Himalaya is implicated as the major control on Indian summer monsoon dynamics today. Since this region has been uplifted since at least the late Oligocene, it is possible to test the response of monsoon precipitation to global and regional climate change, and also understand feedbacks on the climate system via carbon sequestration in the Bengal Fan. The evidence for monsoon intensity changes across the Miocene and Pliocene is currently incomplete given temporal uncertainty and diagenesis in terrestrial records; biases in the records reconstructed from the distal fan; and conflicting evidence from wind speed and aridity metrics for a stronger or weaker monsoon. Our alternative approach is therefore to study the basin-wide hydrological changes recorded in a multi-proxy, multi-site study of the marine sediments of the Bengal Fan recovered during IODP expedition 354. In turbiditic sediments of Himalayan origin, the late Miocene C4 expansion was found in all three long records recovered during expedition 354 (i.e. at sites U1451, U1450 and U1455, from East to West) based on stable carbon isotope composition of terrestrial leaf-wax compounds. Cores from sites U1455 (a reoccupation of DSDP Leg 22 Site 218) provide the highest resolution record of the C4 transition, which appears to occur abruptly within a relatively continuous series of turbiditic sequences. Bio- and magneto-stratigraphic dating of these records by members of Expedition 354 science party is underway and will provide the best stratigraphic constraint of the C4

  6. Mechanism of ENSO influence on the South Asian monsoon rainfall in global model simulations

    Science.gov (United States)

    Joshi, Sneh; Kar, Sarat C.

    2018-02-01

    Coupled ocean atmosphere global climate models are increasingly being used for seasonal scale simulation of the South Asian monsoon. In these models, sea surface temperatures (SSTs) evolve as coupled air-sea interaction process. However, sensitivity experiments with various SST forcing can only be done in an atmosphere-only model. In this study, the Global Forecast System (GFS) model at T126 horizontal resolution has been used to examine the mechanism of El Niño-Southern Oscillation (ENSO) forcing on the monsoon circulation and rainfall. The model has been integrated (ensemble) with observed, climatological and ENSO SST forcing to document the mechanism on how the South Asian monsoon responds to basin-wide SST variations in the Indian and Pacific Oceans. The model simulations indicate that the internal variability gets modulated by the SSTs with warming in the Pacific enhancing the ensemble spread over the monsoon region as compared to cooling conditions. Anomalous easterly wind anomalies cover the Indian region both at 850 and 200 hPa levels during El Niño years. The locations and intensity of Walker and Hadley circulations are altered due to ENSO SST forcing. These lead to reduction of monsoon rainfall over most parts of India during El Niño events compared to La Niña conditions. However, internally generated variability is a major source of uncertainty in the model-simulated climate.

  7. Deep learning for predicting the monsoon over the homogeneous regions of India

    Science.gov (United States)

    Saha, Moumita; Mitra, Pabitra; Nanjundiah, Ravi S.

    2017-06-01

    Indian monsoon varies in its nature over the geographical regions. Predicting the rainfall not just at the national level, but at the regional level is an important task. In this article, we used a deep neural network, namely, the stacked autoencoder to automatically identify climatic factors that are capable of predicting the rainfall over the homogeneous regions of India. An ensemble regression tree model is used for monsoon prediction using the identified climatic predictors. The proposed model provides forecast of the monsoon at a long lead time which supports the government to implement appropriate policies for the economic growth of the country. The monsoon of the central, north-east, north-west, and south-peninsular India regions are predicted with errors of 4.1%, 5.1%, 5.5%, and 6.4%, respectively. The identified predictors show high skill in predicting the regional monsoon having high variability. The proposed model is observed to be competitive with the state-of-the-art prediction models.

  8. The Global Monsoon as Seen through the Divergent Atmospheric Circulation.

    Science.gov (United States)

    Trenberth, Kevin E.; Stepaniak, David P.; Caron, Julie M.

    2000-11-01

    20% of the variance, features relatively shallow but vigorous overturning with the maximum vertical velocities near 800 mb, outflow from 750 to 350 mb, and inflow peaking at 925 mb. It is especially strong over Africa where the shallow, mostly meridional overturning migrates back and forth across the equator with the seasons. It influences the Middle East, has a signature over Australia, and is also an important component of the overturning in the tropical eastern Pacific and Atlantic, and thus of the convergence zones in these regions.The relationship of the global monsoon to the regional monsoons is described over six zonal sectors: Africa, Australia-Asia, North America, South America, and the Pacific and Atlantic Oceans. Only the two ocean areas do not undergo a seasonal reversal required for monsoons, although they have direct overturning cells and they nevertheless participate in the global monsoon through the changes in large-scale overturning. The regional meridional cross sections highlight the importance of the shallow overturning cell in lower-troposphere monsoon activity. The steadiness of the overturning circulation is determined by comparing the signal of the seasonal mean vertical motions at 500 mb with the standard deviation of the transient daily variations. Locations where this signal exceeds 60% of the daily noise correspond closely with the regional centers of the monsoon.

  9. Characteristics of monsoon low level jet (MLLJ)

    Indian Academy of Sciences (India)

    Temperature and wind data are used to describe variation in the strength of the Monsoon Low Level Jet (MLLJ) from an active phase of the monsoon to a break phase. Also estimated are the characteristics of turbulence above and below MLLJ.

  10. Predicting Nitrate Transport under Future Climate Scenarios beneath the Nebraska Management Systems Evaluation Area (MSEA) site

    Science.gov (United States)

    Li, Y.; Akbariyeh, S.; Gomez Peña, C. A.; Bartlet-Hunt, S.

    2017-12-01

    Understanding the impacts of future climate change on soil hydrological processes and solute transport is crucial to develop appropriate strategies to minimize adverse impacts of agricultural activities on groundwater quality. The goal of this work is to evaluate the direct effects of climate change on the fate and transport of nitrate beneath a center-pivot irrigated corn field in Nebraska Management Systems Evaluation Area (MSEA) site. Future groundwater recharge rate and actual evapotranspiration rate were predicted based on an inverse modeling approach using climate data generated by Weather Research and Forecasting (WRF) model under the RCP 8.5 scenario, which was downscaled from global CCSM4 model to a resolution of 24 by 24 km2. A groundwater flow model was first calibrated based on historical groundwater table measurement and was then applied to predict future groundwater table in the period 2057-2060. Finally, predicted future groundwater recharge rate, actual evapotranspiration rate, and groundwater level, together with future precipitation data from WRF, were used in a three-dimensional (3D) model, which was validated based on rich historic data set collected from 1993-1996, to predict nitrate concentration in soil and groundwater from the year 2057 to 2060. Future groundwater recharge was found to be decreasing in the study area compared to average groundwater recharge data from the literature. Correspondingly, groundwater elevation was predicted to decrease (1 to 2 ft) over the five years of simulation. Predicted higher transpiration data from climate model resulted in lower infiltration of nitrate concentration in subsurface within the root zone.

  11. Quantitative Holocene climatic reconstructions for the lower Yangtze region of China

    Science.gov (United States)

    Li, Jianyong; Dodson, John; Yan, Hong; Wang, Weiming; Innes, James B.; Zong, Yongqiang; Zhang, Xiaojian; Xu, Qinghai; Ni, Jian; Lu, Fengyan

    2018-02-01

    Quantitative proxy-based and high-resolution palaeoclimatic datasets are scarce for the lower reaches of the Yangtze River (LYR) basin. This region is in a transitional vegetation zone which is climatologically sensitive; and as a birthplace for prehistorical civilization in China, it is important to understand how palaeoclimatic dynamics played a role in affecting cultural development in the region. We present a pollen-based and regionally-averaged Holocene climatic twin-dataset for mean total annual precipitation (PANN) and mean annual temperature (TANN) covering the last 10,000 years for the LYR region. This is based on the technique of weighted averaging-partial least squares regression to establish robust calibration models for obtaining reliable climatic inferences. The pollen-based reconstructions generally show an early Holocene climatic optimum with both abundant monsoonal rainfall and warm thermal conditions, and a declining pattern of both PANN and TANN values in the middle to late Holocene. The main driving forces behind the Holocene climatic changes in the LYR area are likely summer solar insolation associated with tropical or subtropical macro-scale climatic circulations such as the Intertropical Convergence Zone (ITCZ), Western Pacific Subtropical High (WPSH), and El Niño/Southern Oscillation (ENSO). Regional multi-proxy comparisons indicate that the Holocene variations in precipitation and temperature for the LYR region display an in-phase relationship with other related proxy records from southern monsoonal China and the Indian monsoon-influenced regions, but are inconsistent with the Holocene moisture or temperature records from northern monsoonal China and the westerly-dominated region in northwestern China. Overall, our comprehensive palaeoclimatic dataset and models may be significant tools for understanding the Holocene Asian monsoonal evolution and for anticipating its future dynamics in eastern Asia.

  12. Prediction of monthly rainfall on homogeneous monsoon regions of India based on large scale circulation patterns using Genetic Programming

    Science.gov (United States)

    Kashid, Satishkumar S.; Maity, Rajib

    2012-08-01

    SummaryPrediction of Indian Summer Monsoon Rainfall (ISMR) is of vital importance for Indian economy, and it has been remained a great challenge for hydro-meteorologists due to inherent complexities in the climatic systems. The Large-scale atmospheric circulation patterns from tropical Pacific Ocean (ENSO) and those from tropical Indian Ocean (EQUINOO) are established to influence the Indian Summer Monsoon Rainfall. The information of these two large scale atmospheric circulation patterns in terms of their indices is used to model the complex relationship between Indian Summer Monsoon Rainfall and the ENSO as well as EQUINOO indices. However, extracting the signal from such large-scale indices for modeling such complex systems is significantly difficult. Rainfall predictions have been done for 'All India' as one unit, as well as for five 'homogeneous monsoon regions of India', defined by Indian Institute of Tropical Meteorology. Recent 'Artificial Intelligence' tool 'Genetic Programming' (GP) has been employed for modeling such problem. The Genetic Programming approach is found to capture the complex relationship between the monthly Indian Summer Monsoon Rainfall and large scale atmospheric circulation pattern indices - ENSO and EQUINOO. Research findings of this study indicate that GP-derived monthly rainfall forecasting models, that use large-scale atmospheric circulation information are successful in prediction of All India Summer Monsoon Rainfall with correlation coefficient as good as 0.866, which may appears attractive for such a complex system. A separate analysis is carried out for All India Summer Monsoon rainfall for India as one unit, and five homogeneous monsoon regions, based on ENSO and EQUINOO indices of months of March, April and May only, performed at end of month of May. In this case, All India Summer Monsoon Rainfall could be predicted with 0.70 as correlation coefficient with somewhat lesser Correlation Coefficient (C.C.) values for different

  13. Does SW Monsoon Influence Total Suspended Matter Flux into the Arabian Sea?

    Digital Repository Service at National Institute of Oceanography (India)

    Raghavan, B.R.; Chauhan, O.S.

    Seasonal enhancement in the flux of total suspended matter (TSM) has been attributed to climatology of the SW monsoon (SWM) in time-series trap experiments conducted in the Arabian Sea. To determine the influence of climate on TSM flux, synoptic...

  14. Decoupled warming and monsoon precipitation in East Asia over the last deglaciation

    NARCIS (Netherlands)

    Peterse, F.; Prins, M.A.; Beets, C.J.; Troelstra, S.R.; Zheng, H.B.; Gu, Z.Y.; Schouten, S.; Sinninghe Damsté, J.S.

    2011-01-01

    Our understanding of the continental climate development in East Asia is mainly based on loess-paleosol sequences and summer monsoon precipitation reconstructions based on oxygen isotopes (delta O-18) of stalagmites from several Chinese caves. Based on these records, it is thought that East Asian

  15. Impact of East Asian Summer Monsoon on Surface Ozone Pattern in China

    Science.gov (United States)

    Li, Shu; Wang, Tijian; Huang, Xing; Pu, Xi; Li, Mengmeng; Chen, Pulong; Yang, Xiu-Qun; Wang, Minghuai

    2018-01-01

    Tropospheric ozone plays a key role in regional and global atmospheric and climate systems. In East Asia, ozone can be affected both in concentration level and spatial pattern by typical monsoon climate. This paper uses three different indices to identify the strength of East Asian summer monsoon (EASM) and explores the possible impact of EASM intensity on the ozone pattern through synthetic and process analysis. The difference in ozone between three strong and three weak monsoon years was analyzed using the simulations from regional climate model RegCM4-Chem. It was found that EASM intensity can significantly influence the spatial distribution of ozone in the lower troposphere. When EASM is strong, ozone in the eastern part of China (28°N - 42° N) is reduced, but the inverse is detected in the north and south. The surface ozone difference ranges from -7 to 7 ppbv during the 3 months (June to August) of the EASM, with the most obvious difference in August. Difference of the 3 months' average ozone ranges from -3.5 to 4 ppbv. Process analysis shows that the uppermost factor controlling ozone level during summer monsoon seasons is the chemistry process. Interannual variability of EASM can impact the spatial distribution of ozone through wind in the lower troposphere, cloud cover, and downward shortwave radiation, which affect the transport and chemical formation of ozone. The phenomenon should be addressed when considering the interaction between ozone and the climate in East Asia region.

  16. Breeding in the monsoon : semi-annual reproduction in the Seychelles warbler (Acrocephalus sechellensis)

    NARCIS (Netherlands)

    Komdeur, Jan; Daan, Serge

    2005-01-01

    Despite the absence of pronounced changes in day length, there is considerable climatological seasonality in the tropics. Its expression can be complex like in the monsoon climate of the Indian Ocean Islands. The land mass distribution on both sides of the equator leads to seasonal changes in

  17. The abrupt onset of the modern South Asian monsoon winds

    Digital Repository Service at National Institute of Oceanography (India)

    Betzler, C.; Eberli, G.P.; Kroon, D.; Wright, J.D.; Swart, P.K.; Nath, B.N.; Alvarez-Zarikian, C.A.; Alonso-Garcia, M.; Bialik, O.M.; Blattler, C.L.; Guo, J.; Haffen, S.; Horozal, S.; Inoue, M.; Jovane, L.; Lanci, L.; Laya, J.C.; Mee, A.L.H.; Ludmann, T.; Nakakuni, M.; Niino, K.; Petruny, L.M.; Pratiwi, S.D.; Reijmer, J.J.G.; Reolid, J.; Slagle, A.L.; Sloss, C.R.; Su, X.; Yao, Z.; Young, J.R.

    :29838 | DOI: 10.1038/srep29838 www.nature.com/scientificreports The abrupt onset of the modern South Asian Monsoon winds Christian Betzler1, Gregor P. Eberli2, Dick Kroon3, James D. Wright4, Peter K. Swart2, Bejugam Nagender Nath5, Carlos A. Alvarez....betzler@uni-hamburg.de) Received: 25 April 2016 accepted: 21 June 2016 Published: 20 July 2016 OPEN www.nature.com/scientificreports/ 2Scientific RepoRts | 6:29838 | DOI: 10.1038/srep29838 control, and we propose that the post Miocene Climate Optimum cooling, together...

  18. Differential and enhanced response to climate forcing in diarrheal disease due to rotavirus across a megacity of the developing world.

    Science.gov (United States)

    Martinez, Pamela P; King, Aaron A; Yunus, Mohammad; Faruque, A S G; Pascual, Mercedes

    2016-04-12

    The role of climate forcing in the population dynamics of infectious diseases has typically been revealed via retrospective analyses of incidence records aggregated across space and, in particular, over whole cities. Here, we focus on the transmission dynamics of rotavirus, the main diarrheal disease in infants and young children, within the megacity of Dhaka, Bangladesh. We identify two zones, the densely urbanized core and the more rural periphery, that respond differentially to flooding. Moreover, disease seasonality differs substantially between these regions, spanning variation comparable to the variation from tropical to temperate regions. By combining process-based models with an extensive disease surveillance record, we show that the response to climate forcing is mainly seasonal in the core, where a more endemic transmission resulting from an asymptomatic reservoir facilitates the response to the monsoons. The force of infection in this monsoon peak can be an order of magnitude larger than the force of infection in the more epidemic periphery, which exhibits little or no postmonsoon outbreak in a pattern typical of nearby rural areas. A typically smaller peak during the monsoon season nevertheless shows sensitivity to interannual variability in flooding. High human density in the core is one explanation for enhanced transmission during troughs and an associated seasonal monsoon response in this diarrheal disease, which unlike cholera, has not been widely viewed as climate-sensitive. Spatial demographic, socioeconomic, and environmental heterogeneity can create reservoirs of infection and enhance the sensitivity of disease systems to climate forcing, especially in the populated cities of the developing world.

  19. Detecting human impacts on the flora, fauna, and summer monsoon of Pleistocene Australia

    Directory of Open Access Journals (Sweden)

    G. H. Miller

    2007-08-01

    Full Text Available The moisture balance across northern and central Australia is dominated by changes in the strength of the Australian Summer Monsoon. Lake-level records that record changes in monsoon strength on orbital timescales are most consistent with a Northern Hemisphere insolation control on monsoon strength, a result consistent with recent modeling studies. A weak Holocene monsoon relative to monsoon strength 65–60 ka, despite stronger forcing, suggests a changed monsoon regime after 60 ka. Shortly after 60 ka humans colonized Australia and all of Australia's largest mammals became extinct. Between 60 and 40 ka Australian climate was similar to present and not changing rapidly. Consequently, attention has turned toward plausible human mechanisms for the extinction, with proponents for over-hunting, ecosystem change, and introduced disease. To differentiate between these options we utilize isotopic tracers of diet preserved in eggshells of two large, flightless birds to track the status of ecosystems before and after human colonization. More than 800 dated eggshells of the Australian emu (Dromaius novaehollandiae, an opportunistic, dominantly herbivorous feeder, provide a 140-kyr dietary reconstruction that reveals unprecedented reduction in the bird's food resources about 50 ka, coeval in three distant regions. These data suggest a tree/shrub savannah with occasionally rich grasslands was converted abruptly to the modern desert scrub. The diet of the heavier, extinct Genyornis newtoni, derived from >550 dated eggshells, was more restricted than in co-existing Dromaius, implying a more specialized feeding strategy. We suggest that generalist feeders, such as Dromaius, were able to adapt to a changed vegetation regime, whereas more specialized feeders, such as Genyornis, became extinct. We speculate that ecosystem collapse across arid and semi-arid zones was a consequence of systematic burning by early humans

  20. Tectonic uplift-influenced monsoonal changes promoted hominin occupation of the Luonan Basin: Insights from a loess-paleosol sequence, eastern Qinling Mountains, central China

    Science.gov (United States)

    Fang, Qian; Hong, Hanlie; Zhao, Lulu; Furnes, Harald; Lu, Huayu; Han, Wen; Liu, Yao; Jia, Zhuoyue; Wang, Chaowen; Yin, Ke; Algeo, Thomas J.

    2017-08-01

    Quaternary soil deposits from northern and southern China are distinctly different, reflecting variability of the East Asian monsoon north and south of the Qinling Mountains. Coeval sediments from the transitional climatic zone of central China, which are little studied to date, have the potential to improve our understanding of Quaternary monsoon changes and associated influences on hominin occupation of this region. Here, we investigate in detail a well-preserved and continuous Quaternary loess-paleosol sequence (Shangbaichuan) from the Luonan Basin, using a variety of weathering indices including major and trace element ratios, clay mineralogy, and Fe-oxide mineralogy. The whole-rock samples display similar rare earth element patterns characterized by upper continental crustal ratios: (La/Yb)N ≈ 9.5 and Eu/Eu* ≈ 0.65. Elemental data such as (La/Yb)N, La/Th and Eu/Eu* ratios show a high degree of homogeneity, suggesting that dust in the source region may have been thoroughly mixed and recycled, resulting in all samples having a uniform initial composition. Indices for pedogenic weathering such as Na/K, Ba/Sr, Rb/Sr, CIA, CIW, CPA, PIA, kaolinite/illite, (kaolinite + smectite)/illite, and hematite/(hematite + goethite) exhibit similar secular trends and reveal a four-stage accumulation history. The indices also indicate that the climate was warmer and wetter during the most recent interglacial stage, compared with coeval environments of the Chinese Loess Plateau. Secular changes in weathering intensity can be related to stepwise uplift of the Qinling Mountains and variation in East Asian monsoon intensity, both of which played significant roles in controlling climate evolution in the Luonan Basin. Furthermore, intensified aridity and winter monsoon strength in dust source areas, as evidenced by mineralogic and geochemical changes, may have been due to the mid-Pleistocene climate transition. Based on temporal correlation of warmer and wetter climatic conditions

  1. Climate Change and Human Occupation in Denmark and Syria

    DEFF Research Database (Denmark)

    Schrøder, Niels; Jensen, Gitte; Limborg, Magnus

    2007-01-01

    the main changes in human activities in the areas. It also confirms that the climatic histories of the sites are closely correlated - with strong ties to global causes of climate change. The NAO (North Atlantic Oscillation) caused contrasting rainfall conditions in Denmark and Levant. Over a period of one......Classical sites for studies of human occupation and climatic changes in Denmark and Syria - have been re-examined. A detailed geological/geophysical mapping of selected sites and geochemical /palynological analysis of cores/profiles confirms that climate change has been the decisive factor behind....... The changes in human occupation in Syria and in Denmark both seems to correlate with the proxies of climate change esp. the change from Atlantic to Subboreal around 4000BC, the change from Subboreal to Subatlantic around 500 BC are marked in as well the climate record and archaeological records (monsoon...

  2. Objective spatiotemporal proxy-model comparisons of the Asian monsoon for the last millennium

    Science.gov (United States)

    Anchukaitis, K. J.; Cook, E. R.; Ammann, C. M.; Buckley, B. M.; D'Arrigo, R. D.; Jacoby, G.; Wright, W. E.; Davi, N.; Li, J.

    2008-12-01

    The Asian monsoon system can be studied using a complementary proxy/simulation approach which evaluates climate models using estimates of past precipitation and temperature, and which subsequently applies the best understanding of the physics of the climate system as captured in general circulation models to evaluate the broad-scale dynamics behind regional paleoclimate reconstructions. Here, we use a millennial-length climate field reconstruction of monsoon season summer (JJA) drought, developed from tree- ring proxies, with coupled climate simulations from NCAR CSM1.4 and CCSM3 to evaluate the cause of large- scale persistent droughts over the last one thousand years. Direct comparisons are made between the external forced response within the climate model and the spatiotemporal field reconstruction. In order to identify patterns of drought associated with internal variability in the climate system, we use a model/proxy analog technique which objectively selects epochs in the model that most closely reproduce those observed in the reconstructions. The concomitant ocean-atmosphere dynamics are then interpreted in order to identify and understand the internal climate system forcing of low frequency monsoon variability. We examine specific periods of extensive or intensive regional drought in the 15th, 17th, and 18th centuries, many of which are coincident with major cultural changes in the region.

  3. Calculation of climate factors as an additional criteria to determine agriculturally less favoured areas

    Directory of Open Access Journals (Sweden)

    Tjaša POGAČAR

    2016-04-01

    Full Text Available Climate factors that are proposed to determine agriculturally less favoured areas (LFA in Slovenia were analyzed for the period 1981–2010. Following the instructions of European Commission prepared by Joint Research Centre (JRC 30-years averages of low air temperatures criteria (the vegetation period duration and sums of effective air temperatures and aridity criteria (aridity index AI have to be calculated. Calculations were additionally done using Slovenian Environment Agency (ARSO method, which is slightly different when determining temperature thresholds. Only hilly areas are below the LFA low air temperatures threshold with the lowest located meteorological station in Rateče. According to aridity criteria no area in Slovenia is below the threshold, so meteorological water balance was also examined. Average water balance in the period 1981–2010 was in most of locations lower than in the period 1971–2000. Climate change impacts are already expressed as trend presence in time series of studied variables, so it is recommended to calculate trends and take them into account or to perform regular iterations of calculations.

  4. Coastal Climate Change Education, Mitigation, and Adaptation in the Natural and Built Environments: Progress of the Coastal Areas Climate Change Education Partnership

    Science.gov (United States)

    Feldman, A.; Herman, B.; Vernaza-Hernández, V.; Ryan, J. G.; Muller-Karger, F. E.; Gilbes, F.

    2011-12-01

    The Coastal Area Climate Change Education (CACCE) Partnership, funded by the National Science Foundation, seeks to develop new ways to educate citizens about global climate change. The core themes are sea level rise and impacts of climate change in the southeastern United States and the Caribbean Sea. CACCE focuses on helping partners, educators, students, and the general public gain a fundamental and working understanding of the interrelation among the natural environment, built environment, and social aspects in the context of climate change in coastal regions. To this end, CACCE's objectives reported here include: 1) defining the current state of awareness, perceptions, and literacy about the impacts of climate change; and 2) testing a model of transdisciplinary research and learning as a means of training a new generation of climate professionals. Objective one is met in part by CACCE survey efforts that reveal Florida and Puerto Rico secondary science teachers hold many non-scientific views about climate change and climate change science and provide inadequate instruction about climate change. Associated with objective two are five Multiple Outcome Interdisciplinary Research and Learning (MOIRL) pilot projects underway in schools in Florida and Puerto Rico. In the CACCE Partnership the stakeholders include: students (K-16 and graduate); teachers and education researchers; informal science educators; scientists and engineers; business and industry; policy makers; and community members. CACCE combines interdisciplinary research with action research and community-based participatory research in a way that is best described as "transdisciplinary". Learning occurs in all spheres of interactions among stakeholders as they engage in scientific, educational, community and business activities through their legitimate peripheral participation in research communities of practice. We will describe the process of seeking and building partnerships, and call for a dialogue

  5. Ensemble forecasting shifts in climatically suitable areas for Tropidacris cristata (Orthoptera: Acridoidea: Romaleidae)

    DEFF Research Database (Denmark)

    Diniz, J.A.F.; Nabout, J.C.; Bini, L.M.

    2010-01-01

    niche models, four AOGCMs and two emission scenarios. Combinations of these effects (50 cross-validations for each of the 15 subsets of the environmental variables) were used to estimate and map the occurrence frequencies (EOF) across all analyses. A three-way anova was used to partition and map...... the sources of variation. 3. The projections for 2080 show that the range edges of the species are likely to remain approximately constant, but shifts in maximum EOF are forecasted. Suitable climatic conditions tend to disappear from central areas of Amazon, although this depends on the AOGCM and the niche...

  6. NOAA Climate Data Record (CDR) of Leaf Area Index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), Version 4

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains gridded daily Leaf Area Index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) derived from the NOAA Climate Data...

  7. Air Pollutants, Climate, and the Prevalence of Pediatric Asthma in Urban Areas of China

    Directory of Open Access Journals (Sweden)

    Juanjuan Zhang

    2016-01-01

    Full Text Available Background. Prevalence of childhood asthma varies significantly among regions, while its reasons are not clear yet with only a few studies reporting relevant causes for this variation. Objective. To investigate the potential role of city-average levels of air pollutants and climatic factors in order to distinguish differences in asthma prevalence in China and explain their reasons. Methods. Data pertaining to 10,777 asthmatic patients were obtained from the third nationwide survey of childhood asthma in China’s urban areas. Annual mean concentrations of air pollutants and other climatic factors were obtained for the same period from several government departments. Data analysis was implemented with descriptive statistics, Pearson correlation coefficient, and multiple regression analysis. Results. Pearson correlation analysis showed that the situation of childhood asthma was strongly linked with SO2, relative humidity, and hours of sunshine (p<0.05. Multiple regression analysis indicated that, among the predictor variables in the final step, SO2 was found to be the most powerful predictor variable amongst all (β=-19.572, p < 0.05. Furthermore, results had shown that hours of sunshine (β = -0.014, p < 0.05 was a significant component summary predictor variable. Conclusion. The findings of this study do not suggest that air pollutants or climate, at least in terms of children, plays a major role in explaining regional differences in asthma prevalence in China.

  8. Multi-scale connectivity and graph theory highlight critical areas for conservation under climate change

    Science.gov (United States)

    Dilts, Thomas E.; Weisberg, Peter J.; Leitner, Phillip; Matocq, Marjorie D.; Inman, Richard D.; Nussear, Ken E.; Esque, Todd C.

    2016-01-01

    Conservation planning and biodiversity management require information on landscape connectivity across a range of spatial scales from individual home ranges to large regions. Reduction in landscape connectivity due changes in land-use or development is expected to act synergistically with alterations to habitat mosaic configuration arising from climate change. We illustrate a multi-scale connectivity framework to aid habitat conservation prioritization in the context of changing land use and climate. Our approach, which builds upon the strengths of multiple landscape connectivity methods including graph theory, circuit theory and least-cost path analysis, is here applied to the conservation planning requirements of the Mohave ground squirrel. The distribution of this California threatened species, as for numerous other desert species, overlaps with the proposed placement of several utility-scale renewable energy developments in the American Southwest. Our approach uses information derived at three spatial scales to forecast potential changes in habitat connectivity under various scenarios of energy development and climate change. By disentangling the potential effects of habitat loss and fragmentation across multiple scales, we identify priority conservation areas for both core habitat and critical corridor or stepping stone habitats. This approach is a first step toward applying graph theory to analyze habitat connectivity for species with continuously-distributed habitat, and should be applicable across a broad range of taxa.

  9. Multiscale connectivity and graph theory highlight critical areas for conservation under climate change.

    Science.gov (United States)

    Dilt, Thomas E; Weisberg, Peter J; Leitner, Philip; Matocq, Marjorie D; Inman, Richard D; Nussear, Kenneth E; Esque, Todd C

    2016-06-01

    Conservation planning and biodiversity management require information on landscape connectivity across a range of spatial scales from individual home ranges to large regions. Reduction in landscape connectivity due changes in land use or development is expected to act synergistically with alterations to habitat mosaic configuration arising from climate change. We illustrate a multiscale connectivity framework to aid habitat conservation prioritization in the context of changing land use and climate. Our approach, which builds upon the strengths of multiple landscape connectivity methods, including graph theory, circuit theory, and least-cost path analysis, is here applied to the conservation planning requirements of the Mohave ground squirrel. The distribution of this threatened Californian species, as for numerous other desert species, overlaps with the proposed placement of several utility-scale renewable energy developments in the American southwest. Our approach uses information derived at three spatial scales to forecast potential changes in habitat connectivity under various scenarios of energy development and climate change. By disentangling the potential effects of habitat loss and fragmentation across multiple scales, we identify priority conservation areas for both core habitat and critical corridor or stepping stone habitats. This approach is a first step toward applying graph theory to analyze habitat connectivity for species with continuously distributed habitat and should be applicable across a broad range of taxa.

  10. Monitoring the Impact of Climate Change on Soil Salinity in Agricultural Areas Using Ground and Satellite Sensors

    Science.gov (United States)

    Changes in climatic patterns have had dramatic influence on agricultural areas worldwide, particularly in irrigated arid-zone agricultural areas subjected to recurring drought, such as California’s San Joaquin Valley (SJV), or areas receiving above average rainfall for a decade or more, such as Minn...

  11. Harvested area gaps in China between 1981 and 2010: effects of climatic and land management factors

    Science.gov (United States)

    Yu, Qiangyi; van Vliet, Jasper; Verburg, Peter H.; You, Liangzhi; Yang, Peng; Wu, Wenbin

    2018-04-01

    Previous analyses have shown that cropland in China is intensifying, leading to an increase in crop production. However, these output measures leave the potential for further intensification largely unassessed. This study uses the harvested area gap (HAG), which expresses the amount of harvested area that can be gained if all existing cropland is harvested as frequently as possible, according to their potential limit for multi-cropping. Specifically, we calculate the HAG and changes in the HAG in China between 1981 and 2010. We further assess how climatic and land management factors affect these changes. We find that in China the HAG decreases between the 1980s and the 1990s, and subsequently increases between the 1990s and the 2000s, resulting in a small net increase for the entire study period. The initial decrease in the HAG is the result of an increase in the average multi-cropping index throughout the country, which is larger than the increase in the potential multi-cropping index as a result of the changed climatic factors. The subsequent increase in the HAG is the result of a decrease in average multi-cropping index throughout the country, in combination with a stagnant potential. Despite the overall increase in harvested area in China, many regions, e.g. Northeast and Lower Yangtze, are characterized by an increased HAG, indicating their potential for further increasing the multi-cropping index. The study demonstrates the application of the HAG as a method to identify areas where the harvested area can increase to increase crop production, which is currently underexplored in scientific literature.

  12. Co-evolution of hydrological components under climate change scenarios in the Mediterranean area

    Energy Technology Data Exchange (ETDEWEB)

    Viola, F., E-mail: francesco.viola77@unipa.it; Francipane, A.; Caracciolo, D.; Pumo, D.; La Loggia, G.; Noto, L.V.

    2016-02-15

    ABSTRACT: The Mediterranean area is historically characterized by high human pressure on water resources. Today, while climate is projected to be modified in the future, through precipitation decrease and temperature increase, that jointly and non-linearly may affect runoff, concerns about water availability are increasing. For these reasons, quantitative assessment of future modifications in the mean annual water availability are important; likewise, the description of the future interannual variability of some hydrological components such as runoff and evapotranspiration are highly wished for water management and ecosystems dynamics analyses. This study investigates at basin spatial scale future runoff and evapotranspiration, exploring their probability density functions and their interdependence as functions of climatic changes. In order to do that, a parsimonious conceptual lumped model is here used. The model is forced by different future climate scenarios, generated through a weather generator based on a stochastic downscaling of an ensemble of General Circulation Models (GCMs) realizations. The use of the adopted hydrological model, under reliable stochastic future climate scenarios, allows to project future values of evapotranspiration and runoff in a probabilistic framework and, at the same time, the evaluation of their bivariate frequency distributions for changes through the Multivariate Kernel Density Estimation method. As a case study, a benchmark Mediterranean watershed has been proposed (Imera Meridionale, Italy). Results suggest a radical shift and shape modification of the annual runoff and evapotranspiration probability density functions. Possible implications and impacts on water resources management are here addressed and discussed. - Highlights: • This study investigates at basin spatial scale future runoff and evapotranspiration. • A simple conceptual hydrological model and GCMs realizations have been coupled. • Radical shift and shape

  13. Assessing the impacts of climate change on rice yields in the main rice areas of China

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Fengmei [College of Earth Sciences, The Graduate University of the Chinese Academy of Sciences, 19A, Yuquan Road, Beijing, 100049 (China); Xu, Yinglong; Lin, Erda [Agricultural Environment and Sustainable Development Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081 (China); Yokozawa, Masayuki [National Institute for Agro-environmental Sciences, Tsukuba 305-8604 (Japan); Zhang, Jiahua [Chinese Academy of Meteorological Sciences, Beijing, 100081 (China)

    2007-02-15

    This paper assesses the impact of climate change on irrigated rice yield using B2 climate change scenario from the Regional Climate Model (RCM) and CERES-rice model during 2071--2090. Eight typical rice stations ranging in latitude, longitude, and elevation that are located in the main rice ecological zones of China are selected for impact assessment. First, Crop Estimation through Resource and Environment Synthesis (CERES)-rice model is validated using farm experiment data in selected stations. The simulated results represent satisfactorily the trend of flowering duration and yields. The deviation of simulation within {+-} 10% of observed flowering duration and {+-} 15% of observed yield. Second, the errors of the outputs of RCM due to the difference of topography between station point and grid point is corrected. The corrected output of the RCM used for simulating rice flowering duration and yield is more reliable than the not corrected. Without CO2 direct effect on crop, the results from the assessment explore that B2 climate change scenario would have a negative impact on rice yield at most rice stations and have little impacts at Fuzhou and Kunming. To find the change of inter-annual rice yield, a preliminary assessment is made based on comparative cumulative probability at low and high yield and the coefficient variable of yield between the B2 scenario and baseline. Without the CO2 direct effect on rice yield, the result indicates that frequency for low yield would increase and it reverses for high yield, and the variance for rice yield would increase. It is concluded that high frequency at low yield and high variances of rice yield could pose a threat to rice yield at most selected stations in the main rice areas of China. With the CO2 direct effect on rice yield, rice yield increase in all selected stations.

  14. Co-evolution of hydrological components under climate change scenarios in the Mediterranean area

    International Nuclear Information System (INIS)

    Viola, F.; Francipane, A.; Caracciolo, D.; Pumo, D.; La Loggia, G.; Noto, L.V.

    2016-01-01

    ABSTRACT: The Mediterranean area is historically characterized by high human pressure on water resources. Today, while climate is projected to be modified in the future, through precipitation decrease and temperature increase, that jointly and non-linearly may affect runoff, concerns about water availability are increasing. For these reasons, quantitative assessment of future modifications in the mean annual water availability are important; likewise, the description of the future interannual variability of some hydrological components such as runoff and evapotranspiration are highly wished for water management and ecosystems dynamics analyses. This study investigates at basin spatial scale future runoff and evapotranspiration, exploring their probability density functions and their interdependence as functions of climatic changes. In order to do that, a parsimonious conceptual lumped model is here used. The model is forced by different future climate scenarios, generated through a weather generator based on a stochastic downscaling of an ensemble of General Circulation Models (GCMs) realizations. The use of the adopted hydrological model, under reliable stochastic future climate scenarios, allows to project future values of evapotranspiration and runoff in a probabilistic framework and, at the same time, the evaluation of their bivariate frequency distributions for changes through the Multivariate Kernel Density Estimation method. As a case study, a benchmark Mediterranean watershed has been proposed (Imera Meridionale, Italy). Results suggest a radical shift and shape modification of the annual runoff and evapotranspiration probability density functions. Possible implications and impacts on water resources management are here addressed and discussed. - Highlights: • This study investigates at basin spatial scale future runoff and evapotranspiration. • A simple conceptual hydrological model and GCMs realizations have been coupled. • Radical shift and shape

  15. Climate warming, marine protected areas and the ocean-scale integrity of coral reef ecosystems.

    Directory of Open Access Journals (Sweden)

    Nicholas A J Graham

    Full Text Available Coral reefs have emerged as one of the ecosystems most vulnerable to climate variation and change. While the contribution of a warming climate to the loss of live coral cover has been well documented across large spatial and temporal scales, the associated effects on fish have not. Here, we respond to recent and repeated calls to assess the importance of local management in conserving coral reefs in the context of global climate change. Such information is important, as coral reef fish assemblages are the most species dense vertebrate communities on earth, contributing critical ecosystem functions and providing crucial ecosystem services to human societies in tropical countries. Our assessment of the impacts of the 1998 mass bleaching event on coral cover, reef structural complexity, and reef associated fishes spans 7 countries, 66 sites and 26 degrees of latitude in the Indian Ocean. Using Bayesian meta-analysis we show that changes in the size structure, diversity and trophic composition of the reef fish community have followed coral declines. Although the ocean scale integrity of these coral reef ecosystems has been lost, it is positive to see the effects are spatially variable at multiple scales, with impacts and vulnerability affected by geography but not management regime. Existing no-take marine protected areas still support high biomass of fish, however they had no positive affect on the ecosystem response to large-scale disturbance. This suggests a need for future conservation and management efforts to identify and protect regional refugia, which should be integrated into existing management frameworks and combined with policies to improve system-wide resilience to climate variation and change.

  16. Assessing the impacts of climate change on rice yields in the main rice areas of China

    International Nuclear Information System (INIS)

    Yao, Fengmei; Xu, Yinglong; Lin, Erda; Yokozawa, Masayuki; Zhang, Jiahua

    2007-01-01

    This paper assesses the impact of climate change on irrigated rice yield using B2 climate change scenario from the Regional Climate Model (RCM) and CERES-rice model during 2071--2090. Eight typical rice stations ranging in latitude, longitude, and elevation that are located in the main rice ecological zones of China are selected for impact assessment. First, Crop Estimation through Resource and Environment Synthesis (CERES)-rice model is validated using farm experiment data in selected stations. The simulated results represent satisfactorily the trend of flowering duration and yields. The deviation of simulation within ± 10% of observed flowering duration and ± 15% of observed yield. Second, the errors of the outputs of RCM due to the difference of topography between station point and grid point is corrected. The corrected output of the RCM used for simulating rice flowering duration and yield is more reliable than the not corrected. Without CO2 direct effect on crop, the results from the assessment explore that B2 climate change scenario would have a negative impact on rice yield at most rice stations and have little impacts at Fuzhou and Kunming. To find the change of inter-annual rice yield, a preliminary assessment is made based on comparative cumulative probability at low and high yield and the coefficient variable of yield between the B2 scenario and baseline. Without the CO2 direct effect on rice yield, the result indicates that frequency for low yield would increase and it reverses for high yield, and the variance for rice yield would increase. It is concluded that high frequency at low yield and high variances of rice yield could pose a threat to rice yield at most selected stations in the main rice areas of China. With the CO2 direct effect on rice yield, rice yield increase in all selected stations

  17. Climate warming, marine protected areas and the ocean-scale integrity of coral reef ecosystems.

    Science.gov (United States)

    Graham, Nicholas A J; McClanahan, Tim R; MacNeil, M Aaron; Wilson, Shaun K; Polunin, Nicholas V C; Jennings, Simon; Chabanet, Pascale; Clark, Susan; Spalding, Mark D; Letourneur, Yves; Bigot, Lionel; Galzin, René; Ohman, Marcus C; Garpe, Kajsa C; Edwards, Alasdair J; Sheppard, Charles R C

    2008-08-27

    Coral reefs have emerged as one of the ecosystems most vulnerable to climate variation and change. While the contribution of a warming climate to the loss of live coral cover has been well documented across large spatial and temporal scales, the associated effects on fish have not. Here, we respond to recent and repeated calls to assess the importance of local management in conserving coral reefs in the context of global climate change. Such information is important, as coral reef fish assemblages are the most species dense vertebrate communities on earth, contributing critical ecosystem functions and providing crucial ecosystem services to human societies in tropical countries. Our assessment of the impacts of the 1998 mass bleaching event on coral cover, reef structural complexity, and reef associated fishes spans 7 countries, 66 sites and 26 degrees of latitude in the Indian Ocean. Using Bayesian meta-analysis we show that changes in the size structure, diversity and trophic composition of the reef fish community have followed coral declines. Although the ocean scale integrity of these coral reef ecosystems has been lost, it is positive to see the effects are spatially variable at multiple scales, with impacts and vulnerability affected by geography but not management regime. Existing no-take marine protected areas still support high biomass of fish, however they had no positive affect on the ecosystem response to large-scale disturbance. This suggests a need for future conservation and management efforts to identify and protect regional refugia, which should be integrated into existing management frameworks and combined with policies to improve system-wide resilience to climate variation and change.

  18. Wet scavenging of organic and elemental carbon during summer monsoon and winter monsoon seasons

    Science.gov (United States)

    Sonwani, S.; Kulshrestha, U. C.

    2017-12-01

    In the era of rapid industrialization and urbanization, atmospheric abundance of carbonaceous aerosols is increasing due to more and more fossil fuel consumption. Increasing levels of carbonaceous content have significant adverse effects on air quality, human health and climate. The present study was carried out at Delhi covering summer monsoon (July -Sept) and winter monsoon (Dec-Jan) seasons as wind and other meteorological factors affect chemical composition of precipitation in different manner. During the study, the rainwater and PM10 aerosols were collected in order to understand the scavenging process of elemental and organic carbon. The Rain water samples were collected on event basis. PM10 samples were collected before rain (PR), during rain (DR) and after rain (AR) during 2016-2017. The collected samples were analysed by the thermal-optical reflectance method using IMPROVE-A protocol. In PM10, the levels of organic carbon (OC) and its fractions (OC1, OC2, OC3 and OC4) were found significantly lower in the AR samples as compared to PR and DR samples. A significant positive correlation was noticed between scavenging ratios of organic carbon and rain intensity indicating an efficient wet removal of OC. In contrast to OCs, the levels of elemental carbon and its fractions (EC1, EC2, and EC3) in AR were not distinct during PR and DR. The elemental carbon showed very week correlation with rain intensity in Delhi region which could be explained on the basis of hydrophobic nature of freshly emitted carbon soot. The detailed results will be discussed during the conference.

  19. Performance of ALADIN-Climate/CZ over the area of the Czech Republic in comparison with ENSEMBLES regional climate models

    Czech Academy of Sciences Publication Activity Database

    Crhová, L.; Holtanova, E.; Kalvová, J.; Farda, Aleš

    2014-01-01

    Roč. 58, č. 1 (2014), s. 148-169 ISSN 0039-3169 R&D Projects: GA MŽP(CZ) SP/1A6/108/07 Institutional support: RVO:67179843 Keywords : regional climate model * climate model performance * Taylor diagram * skill score Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 0.806, year: 2014

  20. Regime shift of Indian summer monsoon rainfall to a persistent arid state: external forcing versus internal variability

    Science.gov (United States)

    Srivastava, Ankur; Pradhan, Maheswar; Goswami, B. N.; Rao, Suryachandra A.

    2017-11-01

    The high propensity of deficient monsoon rainfall over the Indian sub-continent in the recent 3 decades (seven deficient monsoons against 3 excess monsoon years) compared to the prior 3 decades has serious implications on the food and water resources in the country. Motivated by the need to understand the high occurrence of deficient monsoon during this period, we examine the change in predictability of the Indian summer monsoon (ISM) and its teleconnections with Indo-Pacific sea surface temperatures between the two periods. The shift in the tropical climate in the late 1970s appears to be one of the major reasons behind this. We find an increased predictability of the ISM in the recent 3 decades owing to reduced `internal' interannual variability (IAV) due to the high-frequency modes, while the `external' IAV arising from the low-frequency modes has remained largely the same. The Indian Ocean Dipole-ISM teleconnection has become positive during the monsoon season in the recent period thereby compensating for the weakened ENSO-ISM teleconnection. The central Pacific El-Niño and the Indian Ocean (IO) warming during the recent 3 decades are working together to realise enhanced ascending motion in the equatorial IO between 70°E and 100°E, preconditioning the Indian monsoon system prone to a deficient state.

  1. Effects of high latitude protected areas on bird communities under rapid climate change.

    Science.gov (United States)

    Santangeli, Andrea; Rajasärkkä, Ari; Lehikoinen, Aleksi

    2017-06-01

    Anthropogenic climate change is rapidly becoming one of the main threats to biodiversity, along with other threats triggered by human-driven land-use change. Species are already responding to climate change by shifting their distributions polewards. This shift may create a spatial mismatch between dynamic species distributions and static protected areas (PAs). As protected areas represent one of the main pillars for preserving biodiversity today and in the future, it is important to assess their contribution in sheltering the biodiversity communities, they were designated to protect. A recent development to investigate climate-driven impacts on biological communities is represented by the community temperature index (CTI). CTI provides a measure of the relative temperature average of a community in a specific assemblage. CTI value will be higher for assemblages dominated by warm species compared with those dominated by cold-dwelling species. We here model changes in the CTI of Finnish bird assemblages, as well as changes in species densities, within and outside of PAs during the past four decades in a large boreal landscape under rapid change. We show that CTI has markedly increased over time across Finland, with this change being similar within and outside PAs and five to seven times slower than the temperature increase. Moreover, CTI has been constantly lower within than outside of PAs, and PAs still support communities, which show colder thermal index than those outside of PAs in the 1970s and 1980s. This result can be explained by the higher relative density of northern species within PAs than outside. Overall, our results provide some, albeit inconclusive, evidence that PAs may play a role in supporting the community of northern species. Results also suggest that communities are, however, shifting rapidly, both inside and outside of PAs, highlighting the need for adjusting conservation measures before it is too late. © 2016 John Wiley & Sons Ltd.

  2. Large-scale overview of the summer monsoon over West Africa during the AMMA field experiment in 2006

    Directory of Open Access Journals (Sweden)

    S. Janicot

    2008-09-01

    Full Text Available The AMMA (African Monsoon Multidisciplinary Analysis program is dedicated to providing a better understanding of the West African monsoon and its influence on the physical, chemical and biological environment regionally and globally, as well as relating variability of this monsoon system to issues of health, water resources, food security and demography for West African nations. Within this framework, an intensive field campaign took place during the summer of 2006 to better document specific processes and weather systems at various key stages of this monsoon season. This campaign was embedded within a longer observation period that documented the annual cycle of surface and atmospheric conditions between 2005 and 2007. The present paper provides a large and regional scale overview of the 2006 summer monsoon season, that includes consideration of of the convective activity, mean atmospheric circulation and synoptic/intraseasonal weather systems, oceanic and land surface conditions, continental hydrology, dust concentration and ozone distribution. The 2006 African summer monsoon was a near-normal rainy season except for a large-scale rainfall excess north of 15° N. This monsoon season was also characterized by a 10-day delayed onset compared to climatology, with convection becoming developed only after 10 July. This onset delay impacted the continental hydrology, soil moisture and vegetation dynamics as well as dust emission. More details of some less-well-known atmospheric features in the African monsoon at intraseasonal and synoptic scales are provided in order to promote future research in these areas.

  3. Environmental Resources of Selected Areas of Hawaii: Climate, Ambient Air Quality, and Noise (DRAFT)

    Energy Technology Data Exchange (ETDEWEB)

    Lombardi, D.A.; Blasing, T.J.; Easterly, C.E.; Hamilton, C.B.

    1994-06-01

    This report has been prepared to make available and archive background scientific data and related information on climate, ambient air quality, and ambient noise levels collected during the preparation of the environmental impact statement (EIS) for Phases 3 and 4 of the Hawaii Geothermal Project (HGP) as defined by the state of hawaii in its April 1989 proposal to Congress. The US Department of Energy (DOE) published a notice in the Federal Register on May 17, 1994 withdrawing its Notice of Intent of February 14, 1992, to prepare the HGP-EIS. Since the state of Hawaii is no longer pursuing or planning to pursue the HGP, DOE considers the project to be terminated. The report presents a general description of the climate and air quality for the islands of Hawaii (henceforth referred to as Hawaii), Maui, and Oahu. It also presents a literature review as baseline information on the health effects of hydrogen sulfide. the scientific background data and related information is being made available for use by others in conducting future scientific research in these areas. This report describes the environmental resources present in the areas studied (i.e., the affected environment) and does not represent an assessment of environmental impacts.

  4. Environmental resources of selected areas of Hawaii: Climate, ambient air quality, and noise

    Energy Technology Data Exchange (ETDEWEB)

    Lombardi, D.A.; Blasing, T.J.; Easterly, C.E.; Reed, R.M. [Oak Ridge National Lab., TN (United States); Hamilton, C.B. [Univ. of Tennessee, Knoxville, TN (United States)

    1995-03-01

    This report has been prepared to make available and archive background scientific data and related information on climate, ambient air quality, and ambient noise levels collected during the preparation of the environmental impact statement (EIS) for Phases 3 and 4 of the Hawaii Geothermal Project (HGP) as defined by the state of Hawaii in its April 1989 proposal to Congress. The US Department of Energy (DOE) published a notice withdrawing its Notice of Intent to prepare the HGP-EIS. Since the state of Hawaii is no longer pursuing or planning to pursue the HGP, DOE considers the project to be terminated. The report presents a general description of the climate add air quality for the islands of Hawaii (henceforth referred to as Hawaii), Maui and Oahu. It also presents a literature review as baseline information on the health effects of sulfide. The scientific background data and related information is being made available for use by others in conducting future scientific research in these areas. This report describes the environmental resources present in the areas studied (i.e., the affected environment) and does not represent an assessment of environmental impacts.

  5. Spatiotemporal Variations of Extreme Precipitation under a Changing Climate in the Three Gorges Reservoir Area (TGRA

    Directory of Open Access Journals (Sweden)

    Mingquan Lü

    2018-01-01

    Full Text Available The Three Gorges Dam (TGD is one of the largest hydroelectric projects in the world. Monitoring the spatiotemporal distribution of extreme precipitation offers valuable information for adaptation and mitigation strategies and reservoir management schemes. This study examined variations in extreme precipitation over the Three Gorges Reservoir area (TGRA in China to investigate the potential role of climate warming and Three Gorges Reservoir (TGR. The trends in extreme precipitation over the TGRA were investigated using the iterative-based Mann–Kendall (MK test and Sen’s slope estimator, based on weather station daily data series and TRMM (Tropical Rainfall Measuring Mission data series. The mean and density distribution of extreme precipitation indices between pre-dam and post-dam, pre-1985 and post-1985, and near and distant reservoir area were assessed by the Mann–Whitney test and the Kolmogorov–Smirnov test. The ratio of extreme precipitation to non-extreme precipitation became larger. The precipitation was characterized by increases in heavy precipitation as well as decreases in light and moderate rain. Comparing extreme precipitation indices between pre-1985 (cooling and post-1985 (warming indicated extreme precipitation has changed to become heavier. Under climate warming, the precipitation amount corresponding to more than the 95th percentile increased at the rate of 6.48%/°C. Results from comparing extreme precipitation for the pre- and post-dam, near reservoir area (NRA and away from the reservoir area (ARA imply an insignificant role of the TGR on rainfall extremes over the TGRA. Moreover, the impoundment of TGR did not exert detectable impacts on the surface relative humidity (RH and water vapor pressure (WP.

  6. Observational Analysis of Two Contrasting Monsoon Years

    Science.gov (United States)

    Karri, S.; Ahmad, R.; Sujata, P.; Jose, S.; Sreenivas, G.; Maurya, D. K.

    2014-11-01

    The Indian summer monsoon rainfall contributes about 75 % of the total annual rainfall and exhibits considerable interannual variations. The agricultural economy of the country depends mainly on the monsoon rainfall. The long-range forecast of the monsoon rainfall is, therefore of significant importance in agricultural planning and other economic activities of the country. There are various parameters which influence the amount of rainfall received during the monsoon. Some of the important parameters considered by the Indian Meteorological Department (IMD) for the study of monsoon are Outgoing Longwave Radiation (OLR), moisture content of the atmosphere, zonal wind speed, low level vorticity, pressure gradient etc. Compared to the Long Period Average (LPA) value of rain fall, the country as a whole received higher amount of rainfall in June, 2013 (34 % more than LPA). The same month showed considerable decrease next year as the amount of rainfall received was around 43 % less compared to LPA. This drastic difference of monsoon prompted to study the behaviour of some of the monsoon relevant parameters. In this study we have considered five atmospheric parameters as the indicators of monsoon behaviour namely vertical relative humidity, OLR, aerosol optical depth (AOD), wind at 850 hPa and mean sea level pressure (MSLP). In the initial analysis of weekly OLR difference for year 2013 and 2014 shows positive values in the month of May over north-western parts of India (region of heat low). This should result in a weaker monsoon in 2014. This is substantiated by the rainfall data received for various stations over India. Inference made based on the analysis of RH profiles coupled with AOD values is in agreement with the rainfall over the corresponding stations.

  7. Correlation and anti-correlation of the East Asian summer and winter monsoons during the last 21,000 years.

    Science.gov (United States)

    Wen, Xinyu; Liu, Zhengyu; Wang, Shaowu; Cheng, Jun; Zhu, Jiang

    2016-06-22

    Understanding the past significant changes of the East Asia Summer Monsoon (EASM) and Winter Monsoon (EAWM) is critical for improving the projections of future climate over East Asia. One key issue that has remained outstanding from the paleo-climatic records is whether the evolution of the EASM and EAWM are correlated. Here, using a set of long-term transient simulations of the climate evolution of the last 21,000 years, we show that the EASM and EAWM are positively correlated on the orbital timescale in response to the precessional forcing, but are anti-correlated on millennial timescales in response to North Atlantic melt water forcing. The relation between EASM and EAWM can differ dramatically for different timescales because of the different response mechanisms, highlighting the complex dynamics of the East Asian monsoon system and the challenges for future projection.

  8. Origins of the Asian-Australian monsoons related to Cenozoic plate movement and Tibetan Plateau uplift - A modeling study

    Science.gov (United States)

    Liu, X.; Dong, B.; Yin, Z. Y.; Smith, R. S.; Guo, Q.

    2017-12-01

    The origin of monsoon is a subject that has attracted much attention in the scientific community and even today it is still controversial. According to geological records, there is conflicting evidence regarding the timings of establishment of the monsoon climates in South Asia, East Asia, and northern Australia. Additionally, different explanations for the monsoon origins have been derived from various numerical simulations. To further investigate the origin and evolution of the Asian and Australian monsoons, we designed a series of numerical experiments using a coupled atmospheric-oceanic general circulation model. Since the Indian-Australian plate has shifted its position significantly during the Cenozoic, together with the large-scale uplift of the Tibetan Plateau (TP), in these experiments we considered the configurations of ocean-land masses and large topographic features based on geological evidence of plate motion and TP uplift in 5 typical Cenozoic geological periods: mid-Paleocene ( 60Ma), late-Eocene ( 40Ma), late-Oligocene ( 25Ma), late-Miocene ( 10Ma), and present day. These experiments allowed us to examine the combined effects of the changes in the land-ocean configuration due to plate movement and TP uplift, they also provided insight into the effects of the high CO2 levels during the Eocene. The simulations revealed that during the Paleocene, the Indian Subcontinent was still positioned in the Southern Hemisphere (SH) and, therefore, its climate behaved as the SH tropical monsoon. By the late Eocene, it moved into the tropical Northern Hemisphere, which allowed the establishment of the South Asian monsoon. In contrast, the East Asian and Australian monsoon did not exist in the late Oligocene. These monsoon systems were established in the Miocene and then enhanced thereafter. Establishments of the low-latitude monsoons in South Asia and Australia were entirely determined by the position of the Indian-Australian plate and not related to the TP uplift

  9. Monsoon rainfall behaviour in recent times on local/regional scale in India

    International Nuclear Information System (INIS)

    Singh, Surender; Rao, V.U.M.; Singh, Diwan

    2002-08-01

    An attempt has been made here to investigate the local/regional monsoon rainfall behaviour in the meteorological sub-division no. 13 comprising the areas of Haryana, Delhi and Chandigarh in India. The monthly monsoon rainfall data of 30 years (1970-99) of different locations in the region were used for the investigation. All locations except Delhi received more rainfall in monsoon season during the decade (1990-99) showing general increasing trend in the rainfall behaviour in recent times. The mean monsoon rainfall at various locations ranged between 324.8 mm at Sirsa and 974.9 mm at Chandigarh. The major amount of monsoon rainfall occurred during the month of July and August in the entire region. Monthly mean rainfall ranged between 37.5 to 144.9 mm (June), 130.6 to 298.2 mm (July), 92.6 to 313.6 mm (August) and 44.0 to 149.4mm (September) at different locations. All the locations in the region exhibited overall increasing trend in monsoon rainfall over the period under study. All locations in the region received their lowest monsoon rainfall in the year 1987 which was a drought year and the season's rainfall ranged between 56.1 mm (Sirsa) and 290.0 mm (Delhi) during this year. Many of the locations observed clusters of fluctuations in their respective monsoon rainfall. The statistical summaries of historical data series (1970-99) gave rainfall information on various time scale. Such information acquires value through its influence on the decision making of the ultimate users. (author)

  10. Quantifying pollution transport from the Asian monsoon anticyclone into the lower stratosphere

    Directory of Open Access Journals (Sweden)

    F. Ploeger

    2017-06-01

    Full Text Available Pollution transport from the surface to the stratosphere within the Asian monsoon circulation may cause harmful effects on stratospheric chemistry and climate. Here, we investigate air mass transport from the monsoon anticyclone into the stratosphere using a Lagrangian chemistry transport model. We show how two main transport pathways from the anticyclone emerge: (i into the tropical stratosphere (tropical pipe, and (ii into the Northern Hemisphere (NH extratropical lower stratosphere. Maximum anticyclone air mass fractions reach around 5 % in the tropical pipe and 15 % in the extratropical lowermost stratosphere over the course of a year. The anticyclone air mass fraction correlates well with satellite hydrogen cyanide (HCN and carbon monoxide (CO observations, confirming that pollution is transported deep into the tropical stratosphere from the Asian monsoon anticyclone. Cross-tropopause transport occurs in a vertical chimney, but with the pollutants transported quasi-horizontally along isentropes above the tropopause into the tropics and NH.

  11. Mapping forests in monsoon Asia with ALOS PALSAR 50-m mosaic images and MODIS imagery in 2010.

    Science.gov (United States)

    Qin, Yuanwei; Xiao, Xiangming; Dong, Jinwei; Zhang, Geli; Roy, Partha Sarathi; Joshi, Pawan Kumar; Gilani, Hammad; Murthy, Manchiraju Sri Ramachandra; Jin, Cui; Wang, Jie; Zhang, Yao; Chen, Bangqian; Menarguez, Michael Angelo; Biradar, Chandrashekhar M; Bajgain, Rajen; Li, Xiangping; Dai, Shengqi; Hou, Ying; Xin, Fengfei; Moore, Berrien

    2016-02-11

    Extensive forest changes have occurred in monsoon Asia, substantially affecting climate, carbon cycle and biodiversity. Accurate forest cover maps at fine spatial resolutions are required to qualify and quantify these effects. In this study, an algorithm was developed to map forests in 2010, with the use of structure and biomass information from the Advanced Land Observation System (ALOS) Phased Array L-band Synthetic Aperture Radar (PALSAR) mosaic dataset and the phenological information from MODerate Resolution Imaging Spectroradiometer (MOD13Q1 and MOD09A1) products. Our forest map (PALSARMOD50 m F/NF) was assessed through randomly selected ground truth samples from high spatial resolution images and had an overall accuracy of 95%. Total area of forests in monsoon Asia in 2010 was estimated to be ~6.3 × 10(6 )km(2). The distribution of evergreen and deciduous forests agreed reasonably well with the median Normalized Difference Vegetation Index (NDVI) in winter. PALSARMOD50 m F/NF map showed good spatial and areal agreements with selected forest maps generated by the Japan Aerospace Exploration Agency (JAXA F/NF), European Space Agency (ESA F/NF), Boston University (MCD12Q1 F/NF), Food and Agricultural Organization (FAO FRA), and University of Maryland (Landsat forests), but relatively large differences and uncertainties in tropical forests and evergreen and deciduous forests.

  12. Investigating extreme flood response to Holocene palaeoclimate in the Chinese monsoonal zone: A palaeoflood case study from the Hanjiang River

    Science.gov (United States)

    Guo, Yongqiang; Huang, Chun Chang; Pang, Jiangli; Zha, Xiaochun; Zhou, Yali; Wang, Longsheng; Zhang, Yuzhu; Hu, Guiming

    2015-06-01

    Palaeoflood events recorded by slackwater deposits (SWDs) were investigated extensively by sedimentological criteria of palaeohydrology along the upper Hanjiang River valley. Modern flood SWDs were collected for comparison with palaeoflood SWD in the same reaches. Three typical palaeoflood SWDs were observed within Holocene loess-soil blanket on the first river terrace land. The grain size distributions of palaeoflood SWDs are similar to modern flood SWDs, whereas they are different from eolian loess and soil. Palaeoflood SWD lies in three major pedo-stratigraphic boundaries (TS/L0, L0/S0, and S0/Lt) in the Holocene loess-soil profiles. The chronology of three palaeoflood episodes was established by OSL dating and pedo-stratigraphic correlation with the well-dated Holocene loess-soil profiles in the upper Hanjiang River basin. Holocene palaeoflood events were dated to 9500-8500, 3200-2800, and 1800-1700 a B.P., respectively. Palaeoflood discharges were estimated by the palaeoflood model (i.e., slope-area method and step-backwater method). The highest discharges are 51,680-53,950 m3 s- 1 at the 11,500-time scale in the Xunyang reach of the upper Hanjiang River valley. Holocene extraordinary hydroclimatic events in the Hanjiang River often result from abnormal atmospheric circulations from Southwest monsoons in the Chinese monsoonal zone. These results provide a regional expression of extreme flood response to Holocene palaeoclimate to understand the effects of global climatic variations on the river system dynamics.

  13. Summer moisture changes in the Lake Qinghai area on the northeastern Tibetan Plateau recorded from a meadow section over the past 8400 yrs

    Science.gov (United States)

    Li, Xiangzhong; Liu, Xiangjun; He, Yuxin; Liu, Weiguo; Zhou, Xin; Wang, Zheng

    2018-02-01

    Holocene climatic and environmental changes on the northeastern Tibetan Plateau (TP) have been widely discussed based on the climatic records from sedimentary cores. However, differences in the reconstructed climatic history from various studies in this region still exist, probably due to influence of climatic proxies from multiple factors and the chronological uncertainties in lacustrine sediments. Here we present records of terrestrial plant δ13C, soil color and total organic carbon content over the past 8400 years from a well-dated meadow section on the northeastern TP. The terrestrial plant δ13C value serves as a good summer precipitation/moisture indicator in the studied region. Soil color property and TOC content are also able to disentangle the moisture evolution history. All the data show much wet climates at 8400-7400 cal yr BP, dry climates at 7400-6000 cal yr BP and then wet conditions with fluctuation at 6000-3200 cal yr BP. Late Holocene moisture appears to be comparable with moist conditions from 6000 to 3200 cal yr BP. By further comparing the climatic variations in the Lake Qinghai area with records of the reconstructed summer temperature and the Asian Monsoon precipitation, we believe that the pattern of moisture/precipitation evolution in the Lake Qinghai area was not completely consistent with regions around Lake Qinghai, probably due to complicated interaction between the East Asian Summer Monsoon and the Indian Summer Monsoon.

  14. Climate Variability and Industrial-Suburban Heat Environment in a Mediterranean Area

    Directory of Open Access Journals (Sweden)

    Giuseppina A. Giorgio

    2017-05-01

    Full Text Available The Urban Heat Island (UHI phenomenon prevalently concerns industrialized countries. It consists of a significant increase in temperatures, especially in industrialized and urbanized areas, in particular, during extreme warm periods like summer. This paper explores the climate variability of temperatures in two stations located in Matera city (Southern Italy, evaluating the increase in temperatures from 1988 to 2015. Moreover, the Corine Land Covers (1990–2000–2006–2012 were used in order to investigate the effect of land use on temperatures. The results obtained confirm the prevalence of UHI phenomena for industrialized areas, highlighting the proposal that the spreading of settlements may further drive these effects on the microclimate. In particular, the presence of industrial structures, even in rural areas, shows a clear increase in summer maximum temperatures. This does not occur in the period before 2000, probably due to the absence of the industrial settlement. On the contrary, from 2000 to 2015, changes are not relevant, but the maximum temperatures have always been higher than in the suburban area (station localized in green zone during daylight hours.

  15. Present and future assessment of growing degree days over selected Greek areas with different climate conditions

    Science.gov (United States)

    Paparrizos, Spyridon; Matzarakis, Andreas

    2017-10-01

    The determination of heat requirements in the first developing phases of plants has been expressed as Growing Degree Days (GDD). The current study focuses on three selected study areas in Greece that are characterised by different climatic conditions due to their location and aims to assess the future variation and spatial distribution of Growing Degree Days (GDD) and how these can affect the main cultivations in the study areas. Future temperature data were obtained and analysed by the ENSEMBLES project. The analysis was performed for the future periods 2021-2050 and 2071-2100 with the A1B and B1 scenarios. Spatial distribution was performed using a combination of dynamical and statistical downscaling technique through ArcGIS 10.2.1. The results indicated that for all the future periods and scenarios, the GDD are expected to increase. Furthermore, the increase in the Sperchios River basin will be the highest, followed by the Ardas and the Geropotamos River basins. Moreover, the cultivation period will be shifted from April-October to April-September which will have social, economical and environmental benefits. Additionally, the spatial distribution indicated that in the upcoming years the existing cultivations can find favourable conditions and can be expanded in mountainous areas as well. On the other hand, due to the rough topography that exists in the study areas, the wide expansion of the existing cultivations into higher altitudes is unaffordable. Nevertheless, new more profitable cultivations can be introduced which can find propitious conditions in terms of GDD.

  16. The Guayas Estuary and sea level corrections to calculate flooding areas for climate change scenarios

    Science.gov (United States)

    Moreano, H. R.; Paredes, N.

    2011-12-01

    The Guayas estuary is the inner area of the Gulf of Guayaquil, it holds a water body of around 5000 km2 and the Puna island divides the water flow in two main streams : El Morro and Estero Salado Channel (length: 90 Km.) and Jambeli and Rio Guayas Channel (length: 125km.). The geometry of the estuarine system with the behavior of the tidal wave (semidiurnal) makes tidal amplitude higher at the head than at the mouth, whereas the wave crest at the head is delayed from one and a half to two hours from that at the mouth and sea level recorded by gages along the estuary are all different because of the wave propagation and mean sea level (msl) calculated for each gage show differences with that of La Libertad which is the base line for all altitudes on land (zero level). A leveling and calculations were made to correct such differences in a way that all gages (msl) records were linked to La Libertad and this in turn allowed a better estimates of flooding areas and draw them on topographic maps where zero level corresponds to the mean sea level at La Libertad. The procedure and mathematical formulation could be applied to any estuary or coastal area and it is a useful tool to calculate such areas especially when impacts are on people or capital goods and related to climate change scenarios.

  17. Hybrid insolation forcing of Pliocene monsoon dynamics in West Africa

    Directory of Open Access Journals (Sweden)

    R. R. Kuechler

    2018-01-01

    Full Text Available The Pliocene is regarded as a potential analogue for future climate with conditions generally warmer-than-today and higher-than-preindustrial atmospheric CO2 levels. Here we present the first orbitally resolved records of continental hydrology and vegetation changes from West Africa for two Pliocene time intervals (5.0–4.6 Ma, 3.6–3.0 Ma, which we compare with records from the last glacial cycle (Kuechler et al., 2013. Our results indicate that changes in local insolation alone are insufficient to explain the full degree of hydrologic variations. Generally two modes of interacting insolation forcings are observed: during eccentricity maxima, when precession was strong, the West African monsoon was driven by summer insolation; during eccentricity minima, when precession-driven variations in local insolation were minimal, obliquity-driven changes in the summer latitudinal insolation gradient became dominant. This hybrid monsoonal forcing concept explains orbitally controlled tropical climate changes, incorporating the forcing mechanism of latitudinal gradients for the Pliocene, which probably increased in importance during subsequent Northern Hemisphere glaciations.

  18. Water erosion on areas planted to potato in Tucumán by climate change.

    Science.gov (United States)

    Rios Caceres, Arq. Estela Alejandra; Rios, Victor Hugo; Lucena, Valeria; Guyot, Elia

    Climate changes, monitored by experts from all over the world, have been a matter of con-sciousness raising about the impacts global warming will have on all areas of interest on the planet. The foreseeable direct impacts expected from this evidence are clear: fewer water reserves for agricultural, industrial and urban use; acceleration of desertification processess; destruction of freshwater ecosystems; ecosystem modification due to a drop in rainfall and an increase in temperature to the north of the XI. Region; disappearance of large areas of snow and ice; severe erosion of unprotected basins; reduced water availability for plants in non irrigated land, due to an increase in rain fall intensity. Climate changes demand from the Argentine society a much greater effort than it has been made up to now to mitigate the impacts on our territory and its inhabitants. Potato crop is of a great economic importance in the agricultural GDP of the province of Tucumán (4th place), the geographic location of its production area a is a fragile agro-ecosystem and for this reason the management of water erosion problems is essential. Therefore the aim of this work is to improve potatoe crop irrigation management through information from satellites combined with farm practice. The digital terrain model was obtained from ASTER images. Irrigation practices were followed by an irrigation management software (FAO) and satellite image processing (ENVI). Preliminary results of this experience enabled, through a multi temporal study, the observation of the evolution of crops and irriga-tion practices rescheduling for next season reducing detected water erosion and economically optimizing productivity.

  19. Integrated analysis of present and future responses of precipitation over selected Greek areas with different climate conditions

    Science.gov (United States)

    Paparrizos, Spyridon; Maris, Fotios; Matzarakis, Andreas

    2016-03-01

    The assessment of future precipitation variations prevailing in an area is essential for the research regarding climate and climate change. The current paper focuses on 3 selected areas in Greece that present different climatic characteristics due to their location and aims to assess and compare the future variation of annual and seasonal precipitation. Future precipitation data from the ENSEMBLES anthropogenic climate-change (ACC) global simulations and the Climate version of the Local Model (CLM) were obtained and analyzed. The climate simulations were performed for the future periods 2021-2050 and 2071-2100 under the A1B and B1 scenarios. Mann-Kendall test was applied to investigate possible trends. Spatial distribution of precipitation was performed using a combination of dynamic and statistical downscaling techniques and Kriging method within ArcGIS 10.2.1. The results indicated that for both scenarios, reference periods and study areas, precipitation is expected to be critically decreased. Additionally, Mann-Kendall test application showed a strong downward trend for every study area. Furthermore, the decrease in precipitation for the Ardas River basin characterized by the continental climate will be tempered, while in the Sperchios River basin it will be smoother due to the influence of some minor climatic variations in the basins' springs in the highlands where milder conditions occur. Precipitation decrease in the Geropotamos River basin which is characterized by Mediterranean climate will be more vigorous. B1 scenario appeared more optimistic for the Ardas and Sperchios River basins, while in the Geropotamos River basin, both applied scenarios brought similar results, in terms of future precipitation response.

  20. The role of potential vorticity anomalies in the Somali Jet on Indian Summer Monsoon Intraseasonal Variability

    Science.gov (United States)

    Rai, P.; Joshi, M.; Dimri, A. P.; Turner, A. G.

    2018-06-01

    The climate of the Indian subcontinent is dominated by rainfall arising from the Indian summer monsoon (ISM) during June to September. Intraseasonal variability during the monsoon is characterized by periods of heavy rainfall interspersed by drier periods, known as active and break events respectively. Understanding and predicting such events is of vital importance for forecasting human impacts such as water resources. The Somali Jet is a key regional feature of the monsoon circulation. In the present study, we find that the spatial structure of Somali Jet potential vorticity (PV) anomalies varies considerably during active and break periods. Analysis of these anomalies shows a mechanism whereby sea surface temperature (SST) anomalies propagate north/northwestwards through the Arabian Sea, caused by a positive feedback loop joining anomalies in SST, convection, modification of PV by diabatic heating and mixing in the atmospheric boundary layer, wind-stress curl, and ocean upwelling processes. The feedback mechanism is consistent with observed variability in the coupled ocean-atmosphere system on timescales of approximately 20 days. This research suggests that better understanding and prediction of monsoon intraseasonal variability in the South Asian monsoon may be gained by analysis of the day-to-day dynamical evolution of PV in the Somali Jet.

  1. Simulation of monsoon intraseasonal variability in NCEP CFSv2 and its role on systematic bias

    Science.gov (United States)

    Goswami, Bidyut B.; Deshpande, Medha; Mukhopadhyay, P.; Saha, Subodh K.; Rao, Suryachandra A.; Murthugudde, Raghu; Goswami, B. N.

    2014-11-01

    We have evaluated the simulation of Indian summer monsoon and its intraseasonal oscillations in the National Centers for Environmental Prediction climate forecast system model version 2 (CFSv2). The dry bias over the Indian landmass in the mean monsoon rainfall is one of the major concerns. In spite of this dry bias, CFSv2 shows a reasonable northward propagation of convection at intraseasonal (30-60 day) time scale. In order to document and understand this dry bias over the Indian landmass in CFSv2 simulations, a two pronged investigation is carried out on the two major facets of Indian summer monsoon: one, the air-sea interactions and two, the large scale vertical heating structure in the model. Our analysis shows a possible bias in the co-evolution of convection and sea surface temperature in CFSv2 over the equatorial Indian Ocean. It is also found that the simulated large scale vertical heat source (Q1) and moisture sink (Q2) over the Indian region are biased relative to observational estimates. Finally, this study provides a possible explanation for the dry precipitation bias over the Indian landmass in the simulated mean monsoon on the basis of the biases associated with the simulated ocean-atmospheric processes and the vertical heating structure. This study also throws some light on the puzzle of CFSv2 exhibiting a reasonable northward propagation at the intraseasonal time scale (30-60 day) despite a drier monsoon over the Indian land mass.

  2. The role of potential vorticity anomalies in the Somali Jet on Indian Summer Monsoon Intraseasonal Variability

    Science.gov (United States)

    Rai, P.; Joshi, M.; Dimri, A. P.; Turner, A. G.

    2017-08-01

    The climate of the Indian subcontinent is dominated by rainfall arising from the Indian summer monsoon (ISM) during June to September. Intraseasonal variability during the monsoon is characterized by periods of heavy rainfall interspersed by drier periods, known as active and break events respectively. Understanding and predicting such events is of vital importance for forecasting human impacts such as water resources. The Somali Jet is a key regional feature of the monsoon circulation. In the present study, we find that the spatial structure of Somali Jet potential vorticity (PV) anomalies varies considerably during active and break periods. Analysis of these anomalies shows a mechanism whereby sea surface temperature (SST) anomalies propagate north/northwestwards through the Arabian Sea, caused by a positive feedback loop joining anomalies in SST, convection, modification of PV by diabatic heating and mixing in the atmospheric boundary layer, wind-stress curl, and ocean upwelling processes. The feedback mechanism is consistent with observed variability in the coupled ocean-atmosphere system on timescales of approximately 20 days. This research suggests that better understanding and prediction of monsoon intraseasonal variability in the South Asian monsoon may be gained by analysis of the day-to-day dynamical evolution of PV in the Somali Jet.

  3. Dependence of Indian monsoon rainfall on moisture fluxes across the Arabian Sea and the impact of coupled model sea surface temperature biases

    Energy Technology Data Exchange (ETDEWEB)

    Levine, Richard C. [Met Office Hadley Centre, Devon (United Kingdom); Turner, Andrew G. [University of Reading, NCAS-Climate, Department of Meteorology, Reading (United Kingdom)

    2012-06-15

    The Arabian Sea is an important moisture source for Indian monsoon rainfall. The skill of climate models in simulating the monsoon and its variability varies widely, while Arabian Sea cold sea surface temperature (SST) biases are common in coupled models and may therefore influence the monsoon and its sensitivity to climate change. We examine the relationship between monsoon rainfall, moisture fluxes and Arabian Sea SST in observations and climate model simulations. Observational analysis shows strong monsoons depend on moisture fluxes across the Arabian Sea, however detecting consistent signals with contemporaneous summer SST anomalies is complicated in the observed system by air/sea coupling and large-scale induced variability such as the El Nino-Southern Oscillation feeding back onto the monsoon through development of the Somali Jet. Comparison of HadGEM3 coupled and atmosphere-only configurations suggests coupled model cold SST biases significantly reduce monsoon rainfall. Idealised atmosphere-only experiments show that the weakened monsoon can be mainly attributed to systematic Arabian Sea cold SST biases during summer and their impact on the monsoon-moisture relationship. The impact of large cold SST biases on atmospheric moisture content over the Arabian Sea, and also the subsequent reduced latent heat release over India, dominates over any enhancement in the land-sea temperature gradient and results in changes to the mean state. We hypothesize that a cold base state will result in underestimation of the impact of larger projected Arabian Sea SST changes in future climate, suggesting that Arabian Sea biases should be a clear target for model development. (orig.)

  4. Integrative assessment of climate change for fast-growing urban areas: Measurement and recommendations for future research

    Science.gov (United States)

    Haase, Dagmar; Volk, Martin

    2017-01-01

    Over the 20th century, urbanization has substantially shaped the surface of Earth. With population rapidly shifting from rural locations towards the cities, urban areas have dramatically expanded on a global scale and represent crystallization points of social, cultural and economic assets and activities. This trend is estimated to persist for the next decades, and particularly the developing countries are expected to face rapid urban growth. The management of this growth will require good governance strategies and planning. By threatening the livelihoods, assets and health as foundations of human activities, another major global change contributor, climate change, became an equally important concern of stakeholders. Based on the climate trends observed over the 20th century, and a spatially explicit model of urbanization, this paper investigates the impacts of climate change in relation to different stages of development of urban areas, thus evolving a more integrated perspective on both processes. As a result, an integrative measure of climate change trends and impacts is proposed and estimated for urban areas worldwide. We show that those areas facing major urban growth are to a large extent also hotspots of climate change. Since most of these hotspots are located in the Global South, we emphasize the need for stakeholders to co-manage both drivers of global change. The presented integrative perspective is seen as a starting point to foster such co-management, and furthermore as a means to facilitate communication and knowledge exchange on climate change impacts. PMID:29232695

  5. Climatic drivers of trait assembly in woody plants in Japan

    Czech Academy of Sciences Publication Activity Database

    Shiono, T.; Kusumoto, B.; Maeshiro, R.; Fujii, S. J.; Götzenberger, Lars; de Bello, Francesco; Kubota, Y.

    2015-01-01

    Roč. 42, č. 6 (2015), s. 1176-1186 ISSN 0305-0270 Institutional support: RVO:67985939 Keywords : climate seasonality * functional diversity * monsoon climate Subject RIV: EH - Ecology, Behaviour Impact factor: 3.997, year: 2015

  6. Modeling the Influences of Aerosols on Pre-Monsoon Circulation and Rainfall over Southeast Asia

    Science.gov (United States)

    Lee, D.; Sud, Y. C.; Oreopoulos, L.; Kim, K.-M.; Lau, W. K.; Kang, I.-S.

    2014-01-01

    We conduct several sets of simulations with a version of NASA's Goddard Earth Observing System, version 5, (GEOS-5) Atmospheric Global Climate Model (AGCM) equipped with a two-moment cloud microphysical scheme to understand the role of biomass burning aerosol (BBA) emissions in Southeast Asia (SEA) in the pre-monsoon period of February-May. Our experiments are designed so that both direct and indirect aerosol effects can be evaluated. For climatologically prescribed monthly sea surface temperatures, we conduct sets of model integrations with and without biomass burning emissions in the area of peak burning activity, and with direct aerosol radiative effects either active or inactive. Taking appropriate differences between AGCM experiment sets, we find that BBA affects liquid clouds in statistically significantly ways, increasing cloud droplet number concentrations, decreasing droplet effective radii (i.e., a classic aerosol indirect effect), and locally suppressing precipitation due to a deceleration of the autoconversion process, with the latter effect apparently also leading to cloud condensate increases. Geographical re-arrangements of precipitation patterns, with precipitation increases downwind of aerosol sources are also seen, most likely because of advection of weakly precipitating cloud fields. Somewhat unexpectedly, the change in cloud radiative effect (cloud forcing) at surface is in the direction of lesser cooling because of decreases in cloud fraction. Overall, however, because of direct radiative effect contributions, aerosols exert a net negative forcing at both the top of the atmosphere and, perhaps most importantly, the surface, where decreased evaporation triggers feedbacks that further reduce precipitation. Invoking the approximation that direct and indirect aerosol effects are additive, we estimate that the overall precipitation reduction is about 40% due to the direct effects of absorbing aerosols, which stabilize the atmosphere and reduce

  7. Climate change effects on extreme flows of water supply area in Istanbul: utility of regional climate models and downscaling method.

    Science.gov (United States)

    Kara, Fatih; Yucel, Ismail

    2015-09-01

    This study investigates the climate change impact on the changes of mean and extreme flows under current and future climate conditions in the Omerli Basin of Istanbul, Turkey. The 15 regional climate model output from the EU-ENSEMBLES project and a downscaling method based on local implications from geophysical variables were used for the comparative analyses. Automated calibration algorithm is used to optimize the parameters of Hydrologiska Byråns Vattenbalansavdel-ning (HBV) model for the study catchment using observed daily temperature and precipitation. The calibrated HBV model was implemented to simulate daily flows using precipitation and temperature data from climate models with and without downscaling method for reference (1960-1990) and scenario (2071-2100) periods. Flood indices were derived from daily flows, and their changes throughout the four seasons and year were evaluated by comparing their values derived from simulations corresponding to the current and future climate. All climate models strongly underestimate precipitation while downscaling improves their underestimation feature particularly for extreme events. Depending on precipitation input from climate models with and without downscaling the HBV also significantly underestimates daily mean and extreme flows through all seasons. However, this underestimation feature is importantly improved for all seasons especially for spring and winter through the use of downscaled inputs. Changes in extreme flows from reference to future increased for the winter and spring and decreased for the fall and summer seasons. These changes were more significant with downscaling inputs. With respect to current time, higher flow magnitudes for given return periods will be experienced in the future and hence, in the planning of the Omerli reservoir, the effective storage and water use should be sustained.

  8. A tripolar pattern as an internal mode of the East Asian summer monsoon

    Science.gov (United States)

    Hirota, Nagio; Takahashi, Masaaki

    2012-11-01

    A tripolar anomaly pattern with centers located around the Philippines, China/Japan, and East Siberia dominantly appears in climate variations of the East Asian summer monsoon. In this study, we extracted this pattern as the first mode of a singular value decomposition (SVD1) over East Asia. The squared covariance fraction of SVD1 was 59 %, indicating that this pattern can be considered a dominant pattern of climate variations. Moreover, the results of numerical experiments suggested that the structure is also a dominant pattern of linear responses, even if external forcing is distributed homogeneously over the Northern Hemisphere. Thus, the tripolar pattern can be considered an internal mode that is characterized by the internal atmospheric processes. In this pattern, the moist processes strengthen the circulation anomalies, the dynamical energy conversion supplies energy to the anomalies, and the Rossby waves propagate northward in the lower troposphere and southeastward in the upper troposphere. These processes are favorable for the pattern to have large amplitude and to influence a large area.

  9. A tripolar pattern as an internal mode of the East Asian summer monsoon

    Energy Technology Data Exchange (ETDEWEB)

    Hirota, Nagio; Takahashi, Masaaki [University of Tokyo, Atmosphere and Ocean Research Institute, Chiba (Japan)

    2012-11-15

    A tripolar anomaly pattern with centers located around the Philippines, China/Japan, and East Siberia dominantly appears in climate variations of the East Asian summer monsoon. In this study, we extracted this pattern as the first mode of a singular value decomposition (SVD1) over East Asia. The squared covariance fraction of SVD1 was 59 %, indicating that this pattern can be considered a dominant pattern of climate variations. Moreover, the results of numerical experiments suggested that the structure is also a dominant pattern of linear responses, even if external forcing is distributed homogeneously over the Northern Hemisphere. Thus, the tripolar pattern can be considered an internal mode that is characterized by the internal atmospheric processes. In this pattern, the moist processes strengthen the circulation anomalies, the dynamical energy conversion supplies energy to the anomalies, and the Rossby waves propagate northward in the lower troposphere and southeastward in the upper troposphere. These processes are favorable for the pattern to have large amplitude and to influence a large area. (orig.)

  10. Lakes or wetlands? A comment on 'The middle Holocene climatic records from Arabia: Reassessing lacustrine environments, shift of ITCZ in Arabian Sea, and impacts of the southwest Indian and African monsoons' by Enzel et al.

    Science.gov (United States)

    Engel, Max; Matter, Albert; Parker, Adrian G.; Parton, Ash; Petraglia, Michael D.; Preston, Gareth W.; Preusser, Frank

    2017-01-01

    Enzel et al. (2015) reassess sedimentary records of Early to Mid-Holocene lake sites in Arabia based on a reinterpretation of published multiproxy data and a qualitative analysis of satellite imagery. The authors conclude that these sites represent palaeo-wetland environments rather than palaeolakes and that the majority of the Arabian Peninsula experienced no or, if at all, only a very minor increase of rainfall at that time mainly due to eastward expansion of the East African Summer Monsoon. We disagree with their reassessment and identify several cases where unequivocal evidence for early Late Pleistocene and Early to Mid-Holocene perennial lake environments in Arabia, lasting for centuries to millennia, was neglected by Enzel et al. (2015). Here we summarize findings which indicate the presence of lakes from the sites of Jubbah, Tayma, Mundafan (all Saudi Arabia), Wahalah, Awafi (both UAE), and the Wahiba Sands (Oman), supported by evidence including occurrence of barnacle colonies in living position, remnant bioclastic shoreline deposits, undisturbed varve formation, shallowing-up lacustrine sequences, various aquatic freshwater, brackish and saline micro- and macrofossils, such as ichnofaunal remains, which are the result of prolonged field-based research. While the precise depth, hydrology and ecology of these water bodies is still not entirely resolved, their perennial nature is indicative of a markedly increased precipitation regime, which, in combination with more abundant groundwater and increased spring outflow in terminal basins fed by charged aquifers, was sufficient to overcome evaporative losses. The palaeolakes' influence on sustaining prehistoric populations is corroborated by the presence of rich archaeological evidence.

  11. Climate

    International Nuclear Information System (INIS)

    Fellous, J.L.

    2005-02-01

    This book starts with a series of about 20 preconceived ideas about climate and climatic change and analyses each of them in the light of the present day knowledge. Using this approach, it makes a status of the reality of the climatic change, of its causes and of the measures to be implemented to limit its impacts and reduce its most harmful consequences. (J.S.)

  12. Effects of Climate Change on the Yield and Cropping Area of Major Food Crops: A Case of Bangladesh

    Directory of Open Access Journals (Sweden)

    Md. Ruhul Amin

    2015-01-01

    Full Text Available The crops that we grow for food need specific climatic conditions to show better performance in view of economic yield. A changing climate could have both beneficial and harmful effects on crops. Keeping the above view in mind, this study is undertaken to investigate the impacts of climate change (viz. changes in maximum temperature, minimum temperature, rainfall, humidity and sunshine on the yield and cropping area of four major food crops (viz. Aus rice, Aman rice, Boro rice and wheat in Bangladesh. Heteroskedasticity and autocorrelation consistent standard error (HAC and feasible generalized least square (FGLS methods were used to determine the climate-crop interrelations using national level time series data for the period of 1972–2010. Findings revealed that the effects of all the climate variables have had significant contributions to the yield and cropping area of major food crops with distinct variation among them. Maximum temperature statistically significantly affected all the food crops’ yield except Aus rice. Maximum temperature also insignificantly affected cropping area of all the crops. Minimum temperature insignificantly affected Aman rice but benefited other three crops’ yield and cropping area. Rainfall significantly benefitted cropping area of Aus rice, but significantly affected both yield and cropping area of Aman rice. Humidity statistically positively contributed to the yield of Aus and Aman rice but, statistically, negatively influenced the cropping area of Aus rice. Sunshine statistically significantly benefitted only Boro rice yield. Overall, maximum temperature adversely affected yield and cropping area of all the major food crops and rainfall severely affected Aman rice only. Concerning the issue of climate change and ensuring food security, the respective authorities thus should give considerable attention to the generation, development and extension of drought (all major food crops and flood (particularly Aman

  13. Potential effects of climate change on riparian areas, wetlands, and groundwater-dependent ecosystems in the Blue Mountains, Oregon, USA

    Directory of Open Access Journals (Sweden)

    Kathleen A. Dwire

    2018-04-01

    Full Text Available Riparian areas, wetlands, and groundwater-dependent ecosystems, which are found at all elevations throughout the Blue Mountains, comprise a small portion of the landscape but have high conservation value because they provide habitat for diverse flora and fauna. The effects of climate change on these special habitats may be especially profound, due to altered snowpack and hydrologic regimes predicted to occur in the near future. The functionality of many riparian areas is currently compromised by water diversions and livestock grazing, which reduces their resilience to additional stresses that a warmer climate may bring. Areas associated with springs and small streams will probably experience near-term changes, and some riparian areas and wetlands may decrease in size over time. A warmer climate and reduced soil moisture could lead to a transition from riparian hardwood species to more drought tolerant conifers and shrubs. Increased frequency and spatial extent of wildfire spreading from upland forests could also affect riparian species composition. The specific effects of climate change will vary, depending on local hydrology (especially groundwater, topography, streamside microclimates, and current conditions and land use. Keywords: Climate change, Groundwater-dependent ecosystems, Riparian areas, Springs, Wetlands

  14. Arctic sea ice area changes in CMIP3 and CMIP5 climate models’ ensembles

    Directory of Open Access Journals (Sweden)

    V. A. Semenov

    2017-01-01

    Full Text Available The shrinking Arctic sea ice cover observed during the last decades is probably the clearest manifestation of ongoing climate change. While climate models in general reproduce the sea ice retreat in the Arctic during the 20th century and simulate further sea ice area loss during the 21st century in response to anthropogenic forcing, the models suffer from large biases and the results exhibit considerable spread. Here, we compare results from the two last generations of climate models, CMIP3 and CMIP5, with respect to total and regional Arctic sea ice change. Different characteristics of sea ice area (SIA in March and September have been analysed for the Entire Arctic, Central Arctic and Barents Sea. Further, the sensitivity of SIA to changes in Northern Hemisphere (NH temperature is investigated and dynamical links between SIA and some atmospheric variability modes are assessed.CMIP3 (SRES A1B and CMIP5 (RCP8.5 models not only simulate a coherent decline of the Arctic SIA but also depict consistent changes in the SIA seasonal cycle. The spatial patterns of SIC variability improve in CMIP5 ensemble, most noticeably in summer when compared to HadISST1 data. A better simulation of summer SIA in the Entire Arctic by CMIP5 models is accompanied by a slightly increased bias for winter season in comparison to CMIP3 ensemble. SIA in the Barents Sea is strongly overestimated by the majority of CMIP3 and CMIP5 models, and projected SIA changes are characterized by a high uncertainty. Both CMIP ensembles depict a significant link between the SIA and NH temperature changes indicating that a part of inter-ensemble SIA spread comes from different temperature sensitivity to anthropogenic forcing. The results suggest that, in general, a sensitivity of SIA to external forcing is enhanced in CMIP5 models. Arctic SIA interannual variability in the end of the 20th century is on average well simulated by both ensembles. To the end of the 21st century, September

  15. Improving preparedness of farmers to Climate Variability: A case study of Vidarbha region of Maharashtra, India

    Science.gov (United States)

    Swami, D.; Parthasarathy, D.; Dave, P.

    2016-12-01

    A key objective of the ongoing research is to understand the risk and vulnerability of agriculture and farming communities with respect to multiple climate change attributes, particularly monsoon variability and hydrology such as ground water availability. Climate Variability has always been a feature affecting Indian agriculture but the nature and characteristics of this variability is not well understood. Indian monsoon patterns are highly variable and most of the studies focus on larger domain such as Central India or Western coast (Ghosh et al., 2009) but district level analysis is missing i.e. the linkage between agriculture and climate variables at finer scale has not been investigated comprehensively. For example, Eastern Vidarbha region in Maharashtra is considered as one of the most agriculturally sensitive region in India, where every year a large number of farmers commit suicide. The main reasons for large number of suicides are climate related stressors such as droughts, hail storms, and monsoon variability aggravated with poor socio-economic conditions. Present study has tried to explore the areas in Vidarbha region of Maharashtra where famers and crop productivity, specifically cotton, sorghum, is highly vulnerable to monsoon variability, hydrological and socio-economic variables which are further modelled to determine the maximal contributing factor towards crops and farmers' vulnerability. After analysis using primary and secondary data, it will aid in decision making regarding field operations such as time of sowing, harvesting and irrigation requirements by optimizing the cropping pattern with climatic, hydrological and socio-economic variables. It also suggests the adaptation strategies to farmers regarding different types of cropping and water harvesting practices, optimized dates and timings for harvesting, sowing, water and nutrient requirements of particular crops according to the specific region. Primarily along with secondary analysis

  16. Monsoon-facilitated characteristics and transport of atmospheric mercury at a high-altitude background site in southwestern China

    Directory of Open Access Journals (Sweden)

    H. Zhang

    2016-10-01

    Full Text Available To better understand the influence of monsoonal climate and transport of atmospheric mercury (Hg in southwestern China, measurements of total gaseous mercury (TGM, defined as the sum of gaseous elemental mercury, GEM, and gaseous oxidized mercury, GOM, particulate bound mercury (PBM and GOM were carried out at Ailaoshan Station (ALS, 2450 m a.s.l. in southwestern China from May 2011 to May 2012. The mean concentrations (± SD for TGM, GOM and PBM were 2.09 ± 0.63, 2.2 ± 2.3 and 31.3 ± 28.4 pg m−3, respectively. TGM showed a monsoonal distribution pattern with relatively higher concentrations (2.22 ± 0.58 ng m−3, p  =  0.021 during the Indian summer monsoon (ISM, from May to September and the east Asia summer monsoon (EASM, from May to September periods than that (1.99 ± 0.66 ng m−3 in the non-ISM period. Similarly, GOM and PBM concentrations were higher during the ISM period than during the non-ISM period. This study suggests that the ISM and the EASM have a strong impact on long-range and transboundary transport of Hg between southwestern China and south and southeast Asia. Several high TGM events were accompanied by the occurrence of northern wind during the ISM period, indicating anthropogenic Hg emissions from inland China could rapidly increase TGM levels at ALS due to strengthening of the EASM. Most of the TGM and PBM events occurred at ALS during the non-ISM period. Meanwhile, high CO concentrations were also observed at ALS, indicating that a strong south tributary of westerlies could have transported Hg from south and southeast Asia to southwestern China during the non-ISM period. The biomass burning in southeast Asia and anthropogenic Hg emissions from south Asia are thought to be the source of atmospheric Hg in remote areas of southwestern China during the non-ISM period.

  17. Global Warming: The Instability of Desert Climate is Enhancing in the Northwest Area in China: A Case Study in the Desert Area in Northwestern China

    OpenAIRE

    Zhao-Feng Chang; Shu-Juan Zhu; Fu-Gui Han; Sheng-Nnian Zhong; Qiang-Qiang Wang; Jian-Hui Zhang

    2013-01-01

    To disclose the relation between the sandstorms change and the temperature changes, a case study in the desert area in northwestern china is investigated. The results showed that: the instability of climate in Minqin desert area is enhancing in the arid desert region in northwest China. Mainly as follows: Variation the annual extreme maximum temperature increasing. Variation of extreme minimum temperature also an increasing trend. Average visibility of sandstorms significantly reduced and the...

  18. Simulation of the Indian summer monsoon onset-phase rainfall using a regional model

    KAUST Repository

    Srinivas, C. V.

    2015-09-11

    This study examines the ability of the Advanced Research WRF (ARW) regional model to simulate Indian summer monsoon (ISM) rainfall climatology in different climate zones during the monsoon onset phase in the decade 2000–2009. The initial and boundary conditions for ARW are provided from the NCEP/NCAR Reanalysis Project (NNRP) global reanalysis. Seasonal onset-phase rainfall is compared with corresponding values from 0.25° IMD (India Meteorological Department) rainfall and NNRP precipitation data over seven climate zones (perhumid, humid, dry/moist, subhumid, dry/moist, semiarid and arid) of India to see whether dynamical downscaling using a regional model yields advantages over just using large-scale model predictions. Results show that the model could simulate the onset phase in terms of progression and distribution of rainfall in most zones (except over the northeast) with good correlations and low error metrics. The observed mean onset dates and their variability over different zones are well reproduced by the regional model over most climate zones. It has been found that the ARW performed similarly to the reanalysis in most zones and improves the onset time by 1 to 3 days in zones 4 and 7, in which the NNRP shows a delayed onset compared to the actual IMD onset times. The variations in the onset-phase rainfall during the below-normal onset (June negative) and above-normal onset (June positive) phases are well simulated. The slight underestimation of onset-phase rainfall in the northeast zone could be due to failure in resolving the wide extent of topographic variations and the associated multiscale interactions in that zone. Spatial comparisons showed improvement of pentad rainfall in both space and quantity in ARW simulations over NNRP data, as evident from a wider eastward distribution of pentad rainfall over the Western Ghats, central and eastern India, as in IMD observations. While NNRP under-represented the high pentad rainfall over northeast, east and

  19. Simulation of the Indian summer monsoon onset-phase rainfall using a regional model

    Directory of Open Access Journals (Sweden)

    C. V. Srinivas

    2015-09-01

    Full Text Available This study examines the ability of the Advanced Research WRF (ARW regional model to simulate Indian summer monsoon (ISM rainfall climatology in different climate zones during the monsoon onset phase in the decade 2000–2009. The initial and boundary conditions for ARW are provided from the NCEP/NCAR Reanalysis Project (NNRP global reanalysis. Seasonal onset-phase rainfall is compared with corresponding values from 0.25° IMD (India Meteorological Department rainfall and NNRP precipitation data over seven climate zones (perhumid, humid, dry/moist, subhumid, dry/moist, semiarid and arid of India to see whether dynamical downscaling using a regional model yields advantages over just using large-scale model predictions. Results show that the model could simulate the onset phase in terms of progression and distribution of rainfall in most zones (except over the northeast with good correlations and low error metrics. The observed mean onset dates and their variability over different zones are well reproduced by the regional model over most climate zones. It has been found that the ARW performed similarly to the reanalysis in most zones and improves the onset time by 1 to 3 days in zones 4 and 7, in which the NNRP shows a delayed onset compared to the actual IMD onset times. The variations in the onset-phase rainfall during the below-normal onset (June negative and above-normal onset (June positive phases are well simulated. The slight underestimation of onset-phase rainfall in the northeast zone could be due to failure in resolving the wide extent of topographic variations and the associated multiscale interactions in that zone. Spatial comparisons showed improvement of pentad rainfall in both space and quantity in ARW simulations over NNRP data, as evident from a wider eastward distribution of pentad rainfall over the Western Ghats, central and eastern India, as in IMD observations. While NNRP under-represented the high pentad rainfall over

  20. Impact of Climate Variability on the Coastal Areas of Argentina and ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Existing information on the geomorphological, social and economic impact of climate ... and assess the impact of climate change in relation to land use regulations and ... IDRC joins more than 800 international delegates at the Resilient Cities ...

  1. Impacts of half a degree additional warming on the Asian summer monsoon rainfall characteristics

    Science.gov (United States)

    Lee, Donghyun; Min, Seung-Ki; Fischer, Erich; Shiogama, Hideo; Bethke, Ingo; Lierhammer, Ludwig; Scinocca, John F.

    2018-04-01

    This study investigates the impacts of global warming of 1.5 °C and 2.0 °C above pre-industrial conditions (Paris Agreement target temperatures) on the South Asian and East Asian monsoon rainfall using five atmospheric global climate models participating in the ‘Half a degree Additional warming, Prognosis and Projected Impacts’ (HAPPI) project. Mean and extreme precipitation is projected to increase under warming over the two monsoon regions, more strongly in the 2.0 °C warmer world. Moisture budget analysis shows that increases in evaporation and atmospheric moisture lead to the additional increases in mean precipitation with good inter-model agreement. Analysis of daily precipitation characteristics reveals that more-extreme precipitation will have larger increase in intensity and frequency responding to the half a degree additional warming, which is more clearly seen over the South Asian monsoon region, indicating non-linear scaling of precipitation extremes with temperature. Strong inter-model relationship between temperature and precipitation intensity further demonstrates that the increased moisture with warming (Clausius-Clapeyron relation) plays a critical role in the stronger intensification of more-extreme rainfall with warming. Results from CMIP5 coupled global climate models under a transient warming scenario confirm that half a degree additional warming would bring more frequent and stronger heavy precipitation events, exerting devastating impacts on the human and natural system over the Asian monsoon region.

  2. Robust features of future climate change impacts on sorghum yields in West Africa

    International Nuclear Information System (INIS)

    Sultan, B; Guan, K; Lobell, D B; Kouressy, M; Biasutti, M; Piani, C; Hammer, G L; McLean, G

    2014-01-01

    West Africa is highly vulnerable to climate hazards and better quantification and understanding of the impact of climate change on crop yields are urgently needed. Here we provide an assessment of near-term climate change impacts on sorghum yields in West Africa and account for uncertainties both in future climate scenarios and in crop models. Towards this goal, we use simulations of nine bias-corrected CMIP5 climate models and two crop models (SARRA-H and APSIM) to evaluate the robustness of projected crop yield impacts in this area. In broad agreement with the full CMIP5 ensemble, our subset of bias-corrected climate models projects a mean warming of +2.8 °C in the decades of 2031–2060 compared to a baseline of 1961–1990 and a robust change in rainfall in West Africa with less rain in the Western part of the Sahel (Senegal, South-West Mali) and more rain in Central Sahel (Burkina Faso, South-West Niger). Projected rainfall deficits are concentrated in early monsoon season in the Western part of the Sahel while positive rainfall changes are found in late monsoon season all over the Sahel, suggesting a shift in the seasonality of the monsoon. In response to such climate change, but without accounting for direct crop responses to CO 2 , mean crop yield decreases by about 16–20% and year-to-year variability increases in the Western part of the Sahel, while the eastern domain sees much milder impacts. Such differences in climate and impacts projections between the Western and Eastern parts of the Sahel are highly consistent across the climate and crop models used in this study. We investigate the robustness of impacts for different choices of cultivars, nutrient treatments, and crop responses to CO 2 . Adverse impacts on mean yield and yield variability are lowest for modern cultivars, as their short and nearly fixed growth cycle appears to be more resilient to the seasonality shift of the monsoon, thus suggesting shorter season varieties could be considered a

  3. Robust features of future climate change impacts on sorghum yields in West Africa

    Science.gov (United States)

    Sultan, B.; Guan, K.; Kouressy, M.; Biasutti, M.; Piani, C.; Hammer, G. L.; McLean, G.; Lobell, D. B.

    2014-10-01

    West Africa is highly vulnerable to climate hazards and better quantification and understanding of the impact of climate change on crop yields are urgently needed. Here we provide an assessment of near-term climate change impacts on sorghum yields in West Africa and account for uncertainties both in future climate scenarios and in crop models. Towards this goal, we use simulations of nine bias-corrected CMIP5 climate models and two crop models (SARRA-H and APSIM) to evaluate the robustness of projected crop yield impacts in this area. In broad agreement with the full CMIP5 ensemble, our subset of bias-corrected climate models projects a mean warming of +2.8 °C in the decades of 2031-2060 compared to a baseline of 1961-1990 and a robust change in rainfall in West Africa with less rain in the Western part of the Sahel (Senegal, South-West Mali) and more rain in Central Sahel (Burkina Faso, South-West Niger). Projected rainfall deficits are concentrated in early monsoon season in the Western part of the Sahel while positive rainfall changes are found in late monsoon season all over the Sahel, suggesting a shift in the seasonality of the monsoon. In response to such climate change, but without accounting for direct crop responses to CO2, mean crop yield decreases by about 16-20% and year-to-year variability increases in the Western part of the Sahel, while the eastern domain sees much milder impacts. Such differences in climate and impacts projections between the Western and Eastern parts of the Sahel are highly consistent across the climate and crop models used in this study. We investigate the robustness of impacts for different choices of cultivars, nutrient treatments, and crop responses to CO2. Adverse impacts on mean yield and yield variability are lowest for modern cultivars, as their short and nearly fixed growth cycle appears to be more resilient to the seasonality shift of the monsoon, thus suggesting shorter season varieties could be considered a potential

  4. Climate trends in a specific Mediterranean viticultural area between 1950 and 2006

    Directory of Open Access Journals (Sweden)

    Frédéric Laget

    2008-09-01

    Significance and impact of study: Climate is a major factor in vine cultivation and in the understanding of viticultural terroirs and wine typicality. The climate trends observed over a 50-year period are discussed in the viticultural context of a Mediterranean region. However, the interaction between climate change and technical progress in viticulture and oenology complicate the analysis over the time frame under consideration.

  5. Climate Change Anticipation on Supporting Capacity of Fishing Environment in the Coastal Area of Tanjungmas Semarang City

    Science.gov (United States)

    Sari, Indah Kurniasih Wahyu; Hadi, Sudharto P.

    2018-02-01

    Climate change is no longer a debate about its existence but already a problem shared between communities, between agencies, between countries even global for handling serious because so many aspects of life and the environment is affected, especially for communities in coastal environments This climate change is a threat to the Earth, because it can affect all aspects of life and will damage the balance of life of Earth Climate change happens slowly in a fairly long period of time and it is a change that is hard to avoid. These Phenomena will give effect to the various facets of life. Semarang as areas located to Java and bordering the Java Sea are at high risk exposed to the impacts of climate change Also not a few residents of the city of Semarang who settled in the northern part of the city of Semarang and also have a livelihood as farmers/peasants and fishermen Many industrial centers or attractions that are prone to impacted by climate change. Thus, the anticipation of climate change on resources support neighborhood of fishermen in the coastal area of Tanjungmas Semarang interesting for further review. This study aims to find out more the influence of climate change on the environment of fishing identify potential danger due to the impacts of climate change on coastal areas of Tanjungmas Semarang The research was conducted through surveys, interviews and field observation without a list of questions to obtain primary and secondary data As for the analysis undertaken, namely the analysis of climate change on the coastal environment, the analysis of productivity of fishermen as well as the analysis of the likelihood of disaster risk at the coast due to climate change. From the results of the study the occurrence of sea rise as one of the indicators of climate change in the coastal City of Semarang to reach 0.8 mm/year and average soil degradation that ranged between 5 - 12 cm/year cause most coastal communities as well as the social life of the agricultural

  6. Age and area predict patterns of species richness in pumice rafts contingent on oceanic climatic zone encountered.

    Science.gov (United States)

    Velasquez, Eleanor; Bryan, Scott E; Ekins, Merrick; Cook, Alex G; Hurrey, Lucy; Firn, Jennifer

    2018-05-01

    The theory of island biogeography predicts that area and age explain species richness patterns (or alpha diversity) in insular habitats. Using a unique natural phenomenon, pumice rafting, we measured the influence of area, age, and oceanic climate on patterns of species richness. Pumice rafts are formed simultaneously when submarine volcanoes erupt, the pumice clasts breakup irregularly, forming irregularly shaped pumice stones which while floating through the ocean are colonized by marine biota. We analyze two eruption events and more than 5,000 pumice clasts collected from 29 sites and three climatic zones. Overall, the older and larger pumice clasts held more species. Pumice clasts arriving in tropical and subtropical climates showed this same trend, where in temperate locations species richness (alpha diversity) increased with area but decreased with age. Beta diversity analysis of the communities forming on pumice clasts that arrived in different climatic zones showed that tropical and subtropical clasts transported similar communities, while species composition on temperate clasts differed significantly from both tropical and subtropical arrivals. Using these thousands of insular habitats, we find strong evidence that area and age but also climatic conditions predict the fundamental dynamics of species richness colonizing pumice clasts.

  7. Coefficient of variation for use in crop area classification across multiple climates

    Science.gov (United States)

    Whelen, Tracy; Siqueira, Paul

    2018-05-01

    In this study, the coefficient of variation (CV) is introduced as a unitless statistical measurement for the classification of croplands using synthetic aperture radar (SAR) data. As a measurement of change, the CV is able to capture changing backscatter responses caused by cycles of planting, growing, and harvesting, and thus is able to differentiate these areas from a more static forest or urban area. Pixels with CV values above a given threshold are classified as crops, and below the threshold are non-crops. This paper uses cross-polarized L-band SAR data from the ALOS PALSAR satellite to classify eleven regions across the United States, covering a wide range of major crops and climates. Two separate sets of classification were done, with the first targeting the optimum classification thresholds for each dataset, and the second using a generalized threshold for all datasets to simulate a large-scale operationalized situation. Overall accuracies for the first phase of classification ranged from 66%-81%, and 62%-84% for the second phase. Visual inspection of the results shows numerous possibilities for improving the classifications while still using the same classification method, including increasing the number and temporal frequency of input images in order to better capture phenological events and mitigate the effects of major precipitation events, as well as more accurate ground truth data. These improvements would make the CV method a viable tool for monitoring agriculture throughout the year on a global scale.

  8. The Use of Woodland Products to Cope with Climate Variability in Communal Areas in Zimbabwe

    Directory of Open Access Journals (Sweden)

    Lotte S. Woittiez

    2013-12-01

    Full Text Available Common lands provide smallholder farmers in Africa with firewood, timber, and feed for livestock, and they are used to complement human diets through the collection of edible nontimber forest products (NTFPs. Farmers have developed coping mechanisms, which they deploy at times of climatic shocks. We aimed to analyze the importance of NTFPs in times of drought and to identify options that could increase the capacity to adapt to climate change. We used participatory techniques, livelihood analysis, observations, and measurements to quantify the use of NTFPs. Communities recognized NTFPs as a mechanism to cope with crop failure. We estimated that indigenous fruits contributed to approximately 20% of the energy intake of wealthier farmers and to approximately 40% of the energy intake of poor farmers in years of inadequate rainfall. Farmers needed to invest a considerable share of their time to collect wild fruits from deforested areas. They recognized that the effectiveness of NTFPs as an adaptation option had become threatened by severe deforestation and by illegal harvesting of fruits by urban traders. Farmers indicated the need to plan future land use to (1 intensify crop production, (2 cultivate trees for firewood, (3 keep orchards of indigenous fruit trees, and (4 improve the quality of grazing lands. Farmers were willing to cultivate trees and to organize communal conservation of indigenous fruits trees. Through participatory exercises, farmers elaborated maps, which were used during land use discussions. The process led to prioritization of pressing land use problems and identification of the support needed: fast-growing trees for firewood, inputs for crop production, knowledge on the cultivation of indigenous fruit trees, and clear regulations and compliance with rules for extraction of NTFPs. Important issues that remain to be addressed are best practices for regeneration and conservation, access rules and implementation, and the

  9. Early warning signal for dengue outbreaks and identification of high risk areas for dengue fever in Colombia using climate and non-climate datasets.

    Science.gov (United States)

    Lee, Jung-Seok; Carabali, Mabel; Lim, Jacqueline K; Herrera, Victor M; Park, Il-Yeon; Villar, Luis; Farlow, Andrew

    2017-07-10

    Dengue has been prevalent in Colombia with high risk of outbreaks in various locations. While the prediction of dengue epidemics will bring significant benefits to the society, accurate forecasts have been a challenge. Given competing health demands in Colombia, it is critical to consider the effective use of the limited healthcare resources by identifying high risk areas for dengue fever. The Climate Risk Factor (CRF) index was constructed based upon temperature, precipitation, and humidity. Considering the conditions necessary for vector survival and transmission behavior, elevation and population density were taken into account. An Early Warning Signal (EWS) model was developed by estimating the elasticity of the climate risk factor function to detect dengue epidemics. The climate risk factor index was further estimated at the smaller geographical unit (5 km by 5 km resolution) to identify populations at high risk. From January 2007 to December 2015, the Early Warning Signal model successfully detected 75% of the total number of outbreaks 1 ~ 5 months ahead of time, 12.5% in the same month, and missed 12.5% of all outbreaks. The climate risk factors showed that populations at high risk are concentrated in the Western part of Colombia where more suitable climate conditions for vector mosquitoes and the high population level were observed compared to the East. This study concludes that it is possible to detect dengue outbreaks ahead of time and identify populations at high risk for various disease prevention activities based upon observed climate and non-climate information. The study outcomes can be used to minimize potential societal losses by prioritizing limited healthcare services and resources, as well as by conducting vector control activities prior to experiencing epidemics.

  10. Distribution of coccolithophores as a potential proxy in paleoceanography: The case of the Oman Sea monsoonal pattern

    Directory of Open Access Journals (Sweden)

    Mojtahedin Elham

    2015-02-01

    Full Text Available High abundances of coccoliths have been observed in surface sediment samples from near the coasts of the Oman Sea in February 2011. At the end of the NE monsoon, the locally observed high Gephyrocapsa oceanica production is hypothesized to respond to local injections of nutrient-rich deep water into the surface water due to sea-surface cooling leading to convection. The most abundant coccolithophore species are G. oceanica followed by Emiliania huxleyi, Helicosphaera carteri, Calcidiscus leptoporus. Some species, such as Gephyrocapsa muellerae, Gephyrocapsa ericsonii, Umbilicosphaera sibogae, Umbellosphaera tenuis and Florisphaera profunda, are rare. The G. oceanica suggested a prevalence of upwelling conditions or high supply of nutrients in the Oman Sea (especially West Jask at the end of the NE monsoon. E. huxleyi showed low relative abundances at the end of the NE monsoon. Due to the location of the Oman Sea in low latitudes with high temperatures, we have observed low abundances of G. muellerae in the study area. Additionally, we have identified low abundances of G. ericsonii at the end of the NE monsoon. Helicosphaera carteri showed a clear negative response with decreasing amounts (relative abundances at the end of the NE monsoon. C. leptoporus, U. sibogae and U. tenuis have very low relative abundances in the NE monsoon and declined extremely at the end of the NE monsoon. F. profunda, which is known to inhabit the lower photic zone (<100 m depht was rarely observed in the samples.

  11. Distribution of coccolithophores as a potential proxy in paleoceanography: The case of the Oman Sea monsoonal pattern

    Science.gov (United States)

    Mojtahedin, Elham; Hadavi, Fatemeh; Lak, Razyeh

    2015-02-01

    High abundances of coccoliths have been observed in surface sediment samples from near the coasts of the Oman Sea in February 2011. At the end of the NE monsoon, the locally observed high Gephyrocapsa oceanica production is hypothesized to respond to local injections of nutrient-rich deep water into the surface water due to sea-surface cooling leading to convection. The most abundant coccolithophore species are G. oceanica followed by Emiliania huxleyi, Helicosphaera carteri, Calcidiscus leptoporus. Some species, such as Gephyrocapsa muellerae, Gephyrocapsa ericsonii, Umbilicosphaera sibogae, Umbellosphaera tenuis and Florisphaera profunda, are rare. The G. oceanica suggested a prevalence of upwelling conditions or high supply of nutrients in the Oman Sea (especially West Jask) at the end of the NE monsoon. E. huxleyi showed low relative abundances at the end of the NE monsoon. Due to the location of the Oman Sea in low latitudes with high temperatures, we have observed low abundances of G. muellerae in the study area. Additionally, we have identified low abundances of G. ericsonii at the end of the NE monsoon. Helicosphaera carteri showed a clear negative response with decreasing amounts (relative abundances) at the end of the NE monsoon. C. leptoporus, U. sibogae and U. tenuis have very low relative abundances in the NE monsoon and declined extremely at the end of the NE monsoon. F. profunda, which is known to inhabit the lower photic zone (<100 m depht) was rarely observed in the samples.

  12. The Abrupt Onset of the Modern South Asian Monsoon Winds (iodp Exp. 359)

    Science.gov (United States)

    Betzler, C.; Eberli, G. P.; Kroon, D.; Wright, J. D.; Swart, P. K.; Nath, B. N.; Reijmer, J.; Alvarez Zarikian, C. A.

    2016-12-01

    The South Asian Monson (SAM) is one of the most extreme features in Earth's climate system, yet its initiation and variations are not well established. The SAM is a seasonal reversal of winds accompanied by changes in precipitation with heavy rain during the summer monsoon. It is one of the most intense annually recurring climatic elements and of immense importance in supplying moisture to the Indian subcontinent thus affecting human population and vegetation, as well as marine biota in the surrounding seas. The seasonal precipitation change is one of the SAM elements most noticed on land, whereas the reversal of the wind regime is the dominating driver of circulation in the central and northern Indian Ocean realm. New data acquired during International Ocean Discovery Program Expedition 359 from the Inner Sea of the Maldives provide a previously unread archive that reveals an abrupt onset of the SAM-linked ocean circulation pattern and its relationship to the long term Neogene climate cooling. In particular it registers ocean current fluctuations and changes of intermediate water mass properties for the last 25 myrs that are directly related to the monsoon. Dating the deposits of SAM wind-driven currents yields an age of 12.9 Ma indicating an abrupt SAM onset, over a short period of 300 kyrs. This coincided with the Indian Ocean Oxygen Minimum Zone expansion as revealed by geochemical tracers and the onset of upwelling reflected by the sediment's content of sedimentary organic matter. A weaker `proto-monsoon' existed between 12.9 and 25 Ma, as mirrored by the sedimentary signature of dust influx. Abrupt SAM initiation favors a strong influence of climate in addition to the tectonic control, and we propose that the post Miocene Climate Optimum cooling, together with increased continentalization and establishment of the bipolar ocean circulation, i.e. the beginning of the modern world, shifted the monsoon over a threshold towards the modern system.

  13. Synchronous multi-decadal climate variability of the whole Pacific areas revealed in tree rings since 1567

    Science.gov (United States)

    Fang, Keyan; Cook, Edward; Guo, Zhengtang; Chen, Deliang; Ou, Tinghai; Zhao, Yan

    2018-02-01

    Oceanic and atmospheric patterns play a crucial role in modulating climate variability from interannual to multi-decadal timescales by causing large-scale co-varying climate changes. The brevity of the existing instrumental records hinders the ability to recognize climate patterns before the industrial era, which can be alleviated using proxies. Unfortunately, proxy based reconstructions of oceanic and atmospheric modes of the past millennia often have modest agreements with each other before the instrumental period, raising questions about the robustness of the reconstructions. To ensure the stability of climate signals in proxy data through time, we first identified tree-ring datasets from distant regions containing coherent variations in Asia and North America, and then interpreted their climate information. We found that the multi-decadal covarying climate patterns of the middle and high latitudinal regions around the northern Pacific Ocean agreed quite well with the climate reconstructions of the tropical and southern Pacific areas. This indicates a synchronous variability at the multi-decadal timescale of the past 430 years for the entire Pacific Ocean. This pattern is closely linked to the dominant mode of the Pacific sea surface temperature (SST) after removing the warming trend. This Pacific multi-decadal SST variability resembles the Interdecadal Pacific Oscillation.

  14. The Diurnal Cycle of the Boundary Layer, Convection, Clouds, and Surface Radiation in a Coastal Monsoon Environment (Darwin Australia)

    Energy Technology Data Exchange (ETDEWEB)

    May, Peter T.; Long, Charles N.; Protat, Alain

    2012-08-01

    The diurnal variation of convection and associated cloud and radiative properties remains a significant issue in global NWP and climate models. This study analyzes observed diurnal variability of convection in a coastal monsoonal environment examining the interaction of convective rain clouds, their associated cloud properties, and the impact on the surface radiation and corresponding boundary layer structure during periods where convection is suppressed or active on the large scale. The analysis uses data from the Tropical Warm Pool International Cloud Experiment (TWP-ICE) as well as routine measurements from the Australian Bureau of Meteorology and the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program. Both active monsoonal and large-scale suppressed (buildup and break) conditions are examined and demonstrate that the diurnal variation of rainfall is much larger during the break periods and the spatial distribution of rainfall is very different between the monsoon and break regimes. During the active monsoon the total net radiative input to the surface is decreased by more than 3 times the amount than during the break regime - this total radiative cloud forcing is found to be dominated by the shortwave (SW) cloud effects because of the much larger optical thicknesses and persistence of long-lasting anvils and cirrus cloud decks associated with the monsoon regime. These differences in monsoon versus break surface radiative energy contribute to low-level air temperature differences in the boundary layer over the land surfaces.

  15. Impacts of interannual variation of the East Asian winter monsoon on aerosol concentrations over eastern China

    Science.gov (United States)

    Zhu, J.; Liao, H.; Li, J.; Feng, J.

    2012-04-01

    China has been experiencing increased concentrations of aerosols, commonly attributed to the large increases in emissions associated with the rapid economic development. We apply a global three-dimensional Goddard Earth Observing System chemical transport model (GEOS-Chem) driven by the NASA/GEOS-4 assimilated meteorological data to quantify the impacts of East Asian winter monsoon (EAWM) on the aerosol concentrations over eastern China. We found that the simulated aerosol concentrations over eastern China have strong interannual variation and negative correlations with the strength of EAWM. Model results show that, accounting for sulfate, nitrate, ammonium, black carbon, and organic carbon aerosols, the winter surface layer PM2.5 concentration averaged over eastern China (110°-125°E, 20°-45°N) can be 17.97% (4.78 µg m-3) higher in the weak monsoon years than that in the strong monsoon years. Regionally, the weakening of EAWM is shown to be able to increase PM2.5 concentration in the middle and lower reach of the Yellow River by 12 µg m-3. This point indicates that climate change associated with variation of EAWM has an essential influence on worsening air quality over eastern China. The possible causes of higher aerosol concentrations in the weak monsoon years may be attributed to the changing in wind fields and planetary boundary layer height between the weak and strong monsoon years. Sensitivity studies are performed to identify the role of chemical reaction associated with temperature and humidity on the higher aerosol concentrations in the weak monsoon years over eastern China.

  16. Role of cold surge and MJO on rainfall enhancement over indonesia during east asian winter monsoon

    Science.gov (United States)

    Fauzi, R. R.; Hidayat, R.

    2018-05-01

    Intensity of precipitation in Indonesia is influenced by convection and propagation of southwest wind. Objective of this study is to analyze the relationship between cold surge and the phenomenon of intra-seasonal climate variability Madden-julian Oscillation (MJO) for affecting precipitation in Indonesia. The data used for identifying the occurrence of cold surge are meridional wind speed data from the ERA-Interim. In addition, this study also used RMM1 and RMM2 index data from Bureau of Meteorology (BOM) for identifying MJO events. The results showed that during East Asian Winter Monsoon (EAWM) in 15 years (2000-2015), there are 362 cold surge events, 186 MJO events, and 113 cold surge events were associated with MJO events. The spread of cold surge can penetrate to equator and brought mass of water vapor that causes dominant precipitation in the Indonesian Sea up to 50-75% from climatological precipitation during EAWM. The MJO convection activity that moves from west to east also increases precipitation, but the distribution of rainfall is wider than cold surge, especially in Eastern Indonesia. MJO and cold surge simultaneously can increase rainfall over 100-150% in any Indonesian region that affected by MJO and cold surge events. The mechanism of heavy rainfall is illustrated by high activity of moisture transport in areas such as Java Sea and coastal areas of Indonesia.

  17. Transport of sulfonamide antibiotics in crop fields during monsoon season.

    Science.gov (United States)

    Park, Jong Yol; Ruidisch, Marianne; Huwe, Bernd

    2016-11-01

    Previous studies have documented the occurrence of veterinary sulfonamide antibiotics in groundwater and rivers located far from pollution sources, although their transport and fate is relatively unknown. In mountainous agricultural fields, the transport behaviour can be influenced by climate, slope and physico-chemical properties of the sulfonamides. The objective of this research is to describe the transport behaviour of three sulfonamide antibiotics (sulfamethoxazole, sulfadimethoxine and sulfamethazine) in sloped agricultural fields located in the Haean catchment, South Korea. During dry and monsoon seasons, a solute transport experiment was conducted in two typical sandy loam agricultural fields after application of antibiotics and potassium bromide as conservative tracers. Field measurement and modelling revealed that frequency and amount of runoff generation indicate a relation between slope and rain intensity during monsoon season. Since the steepness of slope influenced partitioning of precipitation between runoff and subsurface flow, higher loss of sulfonamide antibiotics and bromide by runoff was observed at the steeper sloped field. Bromide on topsoil rapidly infiltrated at high infiltration rates. On the contrary, the sulfonamides were relatively retarded in the upper soil layer due to adsorption onto soil particles. Presence of furrows and ridges affected the distribution of sulfonamide antibiotics in the subsurface due to gradient from wetter furrows to drier ridges induced by topography. Modelling results with HydroGeoSphere matched with background studies that describe physico-chemical properties of the sulfonamides interaction between soil and the antibiotic group, solute transport through vadose zone and runoff generation by storm events.

  18. Response of the Asian summer monsoons to idealized precession and obliquity forcing in a set of GCMs

    Science.gov (United States)

    Bosmans, J. H. C.; Erb, M. P.; Dolan, A. M.; Drijfhout, S. S.; Tuenter, E.; Hilgen, F. J.; Edge, D.; Pope, J. O.; Lourens, L. J.

    2018-05-01

    We examine the response of the Indian and East Asian summer monsoons to separate precession and obliquity forcing, using a set of fully coupled high-resolution models for the first time: EC-Earth, GFDL CM2.1, CESM and HadCM3. We focus on the effect of insolation changes on monsoon precipitation and underlying circulation changes, and find strong model agreement despite a range of model physics, parameterization, and resolution. Our results show increased summer monsoon precipitation at times of increased summer insolation, i.e. minimum precession and maximum obliquity, accompanied by a redistribution of precipitation and convection from ocean to land. Southerly monsoon winds over East Asia are strengthened as a consequence of an intensified land-sea pressure gradient. The response of the Indian summer monsoon is less straightforward. Over south-east Asia low surface pressure is less pronounced and winds over the northern Indian Ocean are directed more westward. An Indian Ocean Dipole pattern emerges, with increased precipitation and convection over the western Indian Ocean. Increased temperatures occur during minimum precession over the Indian Ocean, but not during maximum obliquity when insolation is reduced over the tropics and southern hemisphere during northern hemisphere summer. Evaporation is reduced over the northern Indian Ocean, which together with increased precipitation over the western Indian Ocean dampens the increase of monsoonal precipitation over the continent. The southern tropical Indian Ocean as well as the western tropical Pacific (for precession) act as a moisture source for enhanced monsoonal precipitation. The models are in closest agreement for precession-induced changes, with more model spread for obliquity-induced changes, possibly related to a smaller insolation forcing. Our results indicate that a direct response of the Indian and East Asian summer monsoons to insolation forcing is possible, in line with speleothem records but in

  19. Extended Range Prediction of Indian Summer Monsoon: Current status

    Science.gov (United States)

    Sahai, A. K.; Abhilash, S.; Borah, N.; Joseph, S.; Chattopadhyay, R.; S, S.; Rajeevan, M.; Mandal, R.; Dey, A.

    2014-12-01

    The main focus of this study is to develop forecast consensus in the extended range prediction (ERP) of monsoon Intraseasonal oscillations using a suit of different variants of Climate Forecast sy