Science.gov

Sample records for climate extremes alter

  1. Recent climate extremes alter alpine lake ecosystems

    PubMed Central

    Parker, Brian R.; Vinebrooke, Rolf D.; Schindler, David W.

    2008-01-01

    Here, we show that alpine lake ecosystems are responsive to interannual variation in climate, based on long-term limnological and meteorological data from the Canadian Rockies. In the 2000s, in years with colder winter temperatures, higher winter snowfall, later snowmelt, shorter ice-free seasons, and dryer summers, relative to the 1990s, alpine lakes became clearer, warmer, and mixed to deeper depths. Further, lakes became more dilute and nutrient-poor, the latter leading to significant declines in total phytoplankton biomass. However, increased concentrations of dissolved organic carbon in lake water stimulated the appearance of small mixotrophic algal species, partially offsetting the decline in autotrophic phytoplankton biomass and increasing algal species richness. The climate regime in the 2000s altered the physical, chemical, and biological character and the function of high-elevation aquatic ecosystems. Forecasts of increased climatic variability in the future pose serious ramifications for both the biodiversity and ecosystem function of high-elevation lakes. PMID:18725641

  2. Assessing Regional Scale Variability in Extreme Value Statistics Under Altered Climate Scenarios

    SciTech Connect

    Brunsell, Nathaniel; Mechem, David; Ma, Chunsheng

    2015-02-20

    Recent studies have suggested that low-frequency modes of climate variability can significantly influence regional climate. The climatology associated with extreme events has been shown to be particularly sensitive. This has profound implications for droughts, heat waves, and food production. We propose to examine regional climate simulations conducted over the continental United States by applying a recently developed technique which combines wavelet multi–resolution analysis with information theory metrics. This research is motivated by two fundamental questions concerning the spatial and temporal structure of extreme events. These questions are 1) what temporal scales of the extreme value distributions are most sensitive to alteration by low-frequency climate forcings and 2) what is the nature of the spatial structure of variation in these timescales? The primary objective is to assess to what extent information theory metrics can be useful in characterizing the nature of extreme weather phenomena. Specifically, we hypothesize that (1) changes in the nature of extreme events will impact the temporal probability density functions and that information theory metrics will be sensitive these changes and (2) via a wavelet multi–resolution analysis, we will be able to characterize the relative contribution of different timescales on the stochastic nature of extreme events. In order to address these hypotheses, we propose a unique combination of an established regional climate modeling approach and advanced statistical techniques to assess the effects of low-frequency modes on climate extremes over North America. The behavior of climate extremes in RCM simulations for the 20th century will be compared with statistics calculated from the United States Historical Climatology Network (USHCN) and simulations from the North American Regional Climate Change Assessment Program (NARCCAP). This effort will serve to establish the baseline behavior of climate extremes, the

  3. An extreme climatic event alters marine ecosystem structure in a global biodiversity hotspot

    NASA Astrophysics Data System (ADS)

    Wernberg, Thomas; Smale, Dan A.; Tuya, Fernando; Thomsen, Mads S.; Langlois, Timothy J.; de Bettignies, Thibaut; Bennett, Scott; Rousseaux, Cecile S.

    2013-01-01

    Extreme climatic events, such as heat waves, are predicted to increase in frequency and magnitude as a consequence of global warming but their ecological effects are poorly understood, particularly in marine ecosystems. In early 2011, the marine ecosystems along the west coast of Australia--a global hotspot of biodiversity and endemism--experienced the highest-magnitude warming event on record. Sea temperatures soared to unprecedented levels and warming anomalies of 2-4°C persisted for more than ten weeks along >2,000km of coastline. We show that biodiversity patterns of temperate seaweeds, sessile invertebrates and demersal fish were significantly different after the warming event, which led to a reduction in the abundance of habitat-forming seaweeds and a subsequent shift in community structure towards a depauperate state and a tropicalization of fish communities. We conclude that extreme climatic events are key drivers of biodiversity patterns and that the frequency and intensity of such episodes have major implications for predictive models of species distribution and ecosystem structure, which are largely based on gradual warming trends.

  4. Climate Extremes and Society

    NASA Astrophysics Data System (ADS)

    Mote, Philip

    2009-10-01

    In October 2005, as the United States still was reeling from Hurricane Katrina in August and as the alphabet was too short to contain all of that year's named Atlantic tropical storms (Hurricane Wilma was forming near Jamaica), a timely workshop in Bermuda focused on climate extremes and society (see Eos, 87(3), 25, 17 January 2006). This edited volume, which corresponds roughly to the presentations given at that workshop, offers a fascinating look at the critically important intersection of acute climate stress and human vulnerabilities. A changing climate affects humans and other living things not through the variable that most robustly demonstrates the role of rising greenhouse gases—globally averaged temperature—but through local changes, especially changes in extremes. The first part of this book, “Defining and modeling the nature of weather and climate extremes,” focuses on natural science. The second part, “Impacts of weather and climate extremes,” focuses on societal impacts and responses, emphasizing an insurance industry perspective because a primary sponsor of the workshop was the Risk Prediction Initiative, whose aim is to “support scientific research on topics of interest to its sponsors” (p. 320).

  5. Societal Impacts of Climate Extremes

    NASA Astrophysics Data System (ADS)

    Cutter, S. L.

    2011-12-01

    Direct economic losses from weather and climate-sensitive perils in the US are on the rise averaging more than $10billion annually during the past 50 years, a very conservative estimate. Starting in the 1990s and continuing today, crop and property losses from climate extremes are escalating, especially those related to hurricanes/ tropical storms and floods. The pattern for hazard-related mortality is less clear. However, as the US lacks a comprehensive inventory or database of natural hazard losses, these figures are rough estimates. This paper examines the temporal and spatial pattern of losses from climate-sensitive hazards for the US over the past fifty years. It illustrates that how and what you measure matters in the loss calculus (dollars or deaths, insured versus uninsured losses, impacts, or costs, or extreme versus non extreme events). The paper also examines the geographic variability in losses and the differential burdens of climate hazard losses on people and places in the U.S. The paper concludes with two questions: How can the nation reduce losses from climate-sensitive hazards when we don't know how much and where such losses occur? Furthermore, how can policy makers and practitioners assess the effectiveness of any hazard or disaster risk reduction policy when we lack the fundamental baseline of losses against which to measure progress?

  6. Weather Climate Interactions and Extreme Events in the Climate System

    NASA Astrophysics Data System (ADS)

    Redmond, K. T.

    2014-12-01

    The most pronounced local impacts of climate change would occur in association with extreme weather events superimposed on the altered climate. Thus a major thrust of recent efforts in the climate community has been to assess how extreme regional events such as cold air outbreaks, heat waves, tropical cyclones, floods, droughts, and severe weather might change with the climate. Many of these types of events are poorly simulated in climate models because of insufficient spatial resolution and insufficient quality parameterization of sub grid scale convection and radiation processes. This talk summarizes examples selected from those discussed below of how weather and climate events can be interconnected so that the physics of natural climate and weather phenomena depend on each other, thereby complicating our ability to simulate extreme events. A major focus of the chapter is on the Madden Julian oscillation (MJO), which is associated with alternating eastward-moving planetary scale regions of enhanced and suppressed moist deep convection favoring warm pool regions in the tropics. The MJO modulates weather events around the world and influences the evolution of interannual climate variability. We first discuss how the MJO evolves together with the seasonal cycle, the El Niño/southern oscillation (ENSO), and the extratropical circulation, then continue with a case study illustration of how El Niño is intrinsically coupled to intraseasonal and synoptic weather events such as the MJO and westerly wind bursts. This interconnectedness in the system implies that modeling many types of regional extreme weather events requires more than simply downscaling coarse climate model signals to nested regional models because extreme outcomes in a region can depend on poorly simulated extreme weather in distant parts of the world. The authors hope that an improved understanding of these types of interactions between signals across scales of time and space will ultimately yield

  7. Weather Climate Interactions and Extreme Events in the Climate System

    NASA Astrophysics Data System (ADS)

    Roundy, P. E.

    2015-12-01

    The most pronounced local impacts of climate change would occur in association with extreme weather events superimposed on the altered climate. Thus a major thrust of recent efforts in the climate community has been to assess how extreme regional events such as cold air outbreaks, heat waves, tropical cyclones, floods, droughts, and severe weather might change with the climate. Many of these types of events are poorly simulated in climate models because of insufficient spatial resolution and insufficient quality parameterization of sub grid scale convection and radiation processes. This talk summarizes examples selected from those discussed below of how weather and climate events can be interconnected so that the physics of natural climate and weather phenomena depend on each other, thereby complicating our ability to simulate extreme events. A major focus of the chapter is on the Madden Julian oscillation (MJO), which is associated with alternating eastward-moving planetary scale regions of enhanced and suppressed moist deep convection favoring warm pool regions in the tropics. The MJO modulates weather events around the world and influences the evolution of interannual climate variability. We first discuss how the MJO evolves together with the seasonal cycle, the El Niño/southern oscillation (ENSO), and the extratropical circulation, then continue with a case study illustration of how El Niño is intrinsically coupled to intraseasonal and synoptic weather events such as the MJO and westerly wind bursts. This interconnectedness in the system implies that modeling many types of regional extreme weather events requires more than simply downscaling coarse climate model signals to nested regional models because extreme outcomes in a region can depend on poorly simulated extreme weather in distant parts of the world. The authors hope that an improved understanding of these types of interactions between signals across scales of time and space will ultimately yield

  8. Will extreme climatic events facilitate biological invasions?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Extreme climatic events, such as intense heat waves, hurricanes, floods and droughts, can dramatically affect ecological and evolutionary processes, and more extreme events are projected with ongoing climate change. However, the implications of these events for biological invasions, which themselves...

  9. Streamflow response to increasing precipitation extremes altered by forest management

    NASA Astrophysics Data System (ADS)

    Kelly, Charlene N.; McGuire, Kevin J.; Miniat, Chelcy Ford; Vose, James M.

    2016-04-01

    Increases in extreme precipitation events of floods and droughts are expected to occur worldwide. The increase in extreme events will result in changes in streamflow that are expected to affect water availability for human consumption and aquatic ecosystem function. We present an analysis that may greatly improve current streamflow models by quantifying the impact of the interaction between forest management and precipitation. We use daily long-term data from paired watersheds that have undergone forest harvest or species conversion. We find that interactive effects of climate change, represented by changes in observed precipitation trends, and forest management regime, significantly alter expected streamflow most often during extreme events, ranging from a decrease of 59% to an increase of 40% in streamflow, depending upon management. Our results suggest that vegetation might be managed to compensate for hydrologic responses due to climate change to help mitigate effects of extreme changes in precipitation.

  10. The timing of anthropogenic emergence in simulated climate extremes

    NASA Astrophysics Data System (ADS)

    King, Andrew D.; Donat, Markus G.; Fischer, Erich M.; Hawkins, Ed; Alexander, Lisa V.; Karoly, David J.; Dittus, Andrea J.; Lewis, Sophie C.; Perkins, Sarah E.

    2015-09-01

    Determining the time of emergence of climates altered from their natural state by anthropogenic influences can help inform the development of adaptation and mitigation strategies to climate change. Previous studies have examined the time of emergence of climate averages. However, at the global scale, the emergence of changes in extreme events, which have the greatest societal impacts, has not been investigated before. Based on state-of-the-art climate models, we show that temperature extremes generally emerge slightly later from their quasi-natural climate state than seasonal means, due to greater variability in extremes. Nevertheless, according to model evidence, both hot and cold extremes have already emerged across many areas. Remarkably, even precipitation extremes that have very large variability are projected to emerge in the coming decades in Northern Hemisphere winters associated with a wettening trend. Based on our findings we expect local temperature and precipitation extremes to already differ significantly from their previous quasi-natural state at many locations or to do so in the near future. Our findings have implications for climate impacts and detection and attribution studies assessing observed changes in regional climate extremes by showing whether they will likely find a fingerprint of anthropogenic climate change.

  11. Climate extremes and climate change: The Russian heat wave and other climate extremes of 2010

    NASA Astrophysics Data System (ADS)

    Trenberth, Kevin E.; Fasullo, John T.

    2012-09-01

    A global perspective is developed on a number of high impact climate extremes in 2010 through diagnostic studies of the anomalies, diabatic heating, and global energy and water cycles that demonstrate relationships among variables and across events. Natural variability, especially ENSO, and global warming from human influences together resulted in very high sea surface temperatures (SSTs) in several places that played a vital role in subsequent developments. Record high SSTs in the Northern Indian Ocean in May 2010, the Gulf of Mexico in August 2010, the Caribbean in September 2010, and north of Australia in December 2010 provided a source of unusually abundant atmospheric moisture for nearby monsoon rains and flooding in Pakistan, Colombia, and Queensland. The resulting anomalous diabatic heating in the northern Indian and tropical Atlantic Oceans altered the atmospheric circulation by forcing quasi-stationary Rossby waves and altering monsoons. The anomalous monsoonal circulations had direct links to higher latitudes: from Southeast Asia to southern Russia, and from Colombia to Brazil. Strong convection in the tropical Atlantic in northern summer 2010 was associated with a Rossby wave train that extended into Europe creating anomalous cyclonic conditions over the Mediterranean area while normal anticyclonic conditions shifted downstream where they likely interacted with an anomalously strong monsoon circulation, helping to support the persistent atmospheric anticyclonic regime over Russia. This set the stage for the "blocking" anticyclone and associated Russian heat wave and wild fires. Attribution is limited by shortcomings in models in replicating monsoons, teleconnections and blocking.

  12. Extreme Rainfall Events Over Southern Africa: Assessment of a Climate Model to Reproduce Daily Extremes

    NASA Astrophysics Data System (ADS)

    Williams, C.; Kniveton, D.; Layberry, R.

    2007-12-01

    It is increasingly accepted that any possible climate change will not only have an influence on mean climate but may also significantly alter climatic variability. This issue is of particular importance for environmentally vulnerable regions such as southern Africa. The subcontinent is considered especially vulnerable extreme events, due to a number of factors including extensive poverty, disease and political instability. Rainfall variability and the identification of rainfall extremes is a function of scale, so high spatial and temporal resolution data are preferred to identify extreme events and accurately predict future variability. The majority of previous climate model verification studies have compared model output with observational data at monthly timescales. In this research, the assessment of a state-of-the-art climate model to simulate climate at daily timescales is carried out using satellite derived rainfall data from the Microwave Infra-Red Algorithm (MIRA). This dataset covers the period from 1993-2002 and the whole of southern Africa at a spatial resolution of 0.1 degree longitude/latitude. Once the model's ability to reproduce extremes has been assessed, idealised regions of SST anomalies are used to force the model, with the overall aim of investigating the ways in which SST anomalies influence rainfall extremes over southern Africa. In this paper, results from sensitivity testing of the UK Meteorological Office Hadley Centre's climate model's domain size are firstly presented. Then simulations of current climate from the model, operating in both regional and global mode, are compared to the MIRA dataset at daily timescales. Thirdly, the ability of the model to reproduce daily rainfall extremes will be assessed, again by a comparison with extremes from the MIRA dataset. Finally, the results from the idealised SST experiments are briefly presented, suggesting associations between rainfall extremes and both local and remote SST anomalies.

  13. The Pace of Perceivable Extreme Climate Change

    NASA Astrophysics Data System (ADS)

    Tan, X.; Gan, T. Y.

    2015-12-01

    When will the signal of obvious changes in extreme climate emerge over climate variability (Time of Emergence, ToE) is a key question for planning and implementing measures to mitigate the potential impact of climate change to natural and human systems that are generally adapted to potential changes from current variability. We estimated ToEs for the magnitude, duration and frequency of global extreme climate represented by 24 extreme climate indices (16 for temperature and 8 for precipitation) with different thresholds of the signal-to-noise (S/N) ratio based on projections of CMIP5 global climate models under RCP8.5 and RCP4.5 for the 21st century. The uncertainty of ToE is assessed by using 3 different methods to calculate S/N for each extreme index. Results show that ToEs of the projected extreme climate indices based on the RCP4.5 climate scenarios are generally projected to happen about 20 years later than that for the RCP8.5 climate scenarios. Under RCP8.5, the projected magnitude, duration and frequency of extreme temperature on Earth will all exceed 2 standard deviations by 2100, and the empirical 50th percentile of the global ToE for the frequency and magnitude of hot (cold) extreme are about 2040 and 2054 (2064 and 2054) for S/N > 2, respectively. The 50th percentile of global ToE for the intensity of extreme precipitation is about 2030 and 2058 for S/N >0.5 and S/N >1, respectively. We further evaluated the exposure of ecosystems and human societies to the pace of extreme climate change by determining the year of ToE for various extreme climate indices projected to occur over terrestrial biomes, marine realms and major urban areas with large populations. This was done by overlaying terrestrial, ecoregions and population maps with maps of ToE derived, to extract ToEs for these regions. Possible relationships between GDP per person and ToE are also investigated by relating the mean ToE for each country and its average value of GDP per person.

  14. Have Large Dams Altered Extreme Precipitation Patterns?

    NASA Astrophysics Data System (ADS)

    Hossain, Faisal; Jeyachandran, Indumathi; Pielke, Roger

    2009-12-01

    Dams and their impounded waters are among the most common civil infrastructures, with a long heritage of modern design and operations experience. In particular, large dams, defined by the International Commission on Large Dams (ICOLD) as having a height greater than 15 meters from the foundation and holding a reservoir volume of more than 3 million cubic meters, have the potential to vastly transform local climate, landscapes, regional economics, and urbanization patterns. In the United States alone, about 75,000 dams are capable of storing a volume of water equaling almost 1 year's mean runoff of the nation [Graf, 1999]. The World Commission on Dams (WCD) reports that at least 45,000 large dams have been built worldwide since the 1930s. These sheer numbers raise the question of the extent to which large dams and their impounded waters alter patterns that would have been pervasive had the dams not been built.

  15. Climate extremes and the carbon cycle (Invited)

    NASA Astrophysics Data System (ADS)

    Reichstein, M.; Bahn, M.; Ciais, P.; Mahecha, M. D.; Seneviratne, S. I.; Zscheischler, J.

    2013-12-01

    The terrestrial biosphere is a key component of the global carbon cycle and its carbon balance is strongly influenced by climate. Ongoing environmental changes are thought to increase global terrestrial carbon uptake. But evidence is mounting that rare climate extremes can lead to a decrease in ecosystem carbon stocks and therefore have the potential to negate the expected increase in terrestrial carbon uptake. Here we explore the mechanisms and impacts of climate extremes on the terrestrial carbon cycle, and propose a pathway to improve our understanding of present and future impacts of climate extremes on the terrestrial carbon budget. In addition to direct impact on the carbon fluxes of photosynthesis and respiration via extreme temperature and (or) drought, effects of extreme events may also lead to lagged responses, such as wildfires triggered by heat waves and droughts, or pest and pathogen outbreaks following wind-throw caused by heavy storms, reduced plant health due to drought stress or due to less frequent cold extremes in presently cold regions. One extreme event can potentially override accumulated previous carbon sinks, as shown by the Western European 2003 heat wave.. Extreme events have the potential to affect the terrestrial ecosystem carbon balance through a single factor, or as a combination of factors. Climate extremes can cause carbon losses from accumulated stocks, as well as long-lasting impacts on (e.g. lagged effects) on plant growth and mortality, extending beyond the duration of the extreme event itself. The sensitivity of terrestrial ecosystems and their carbon balance to climate change and extreme events varies according to the type of extreme, the climatic region, the land cover, and the land management. Extreme event impacts are very relevant in forests due to the importance of lagged and memory effects on tree growth and mortality, the longevity of tree species, the large forest carbon stocks and their vulnerability, as well as the

  16. Rainfall variability and extremes over southern Africa: assessment of a climate model to reproduce daily extremes

    NASA Astrophysics Data System (ADS)

    Williams, C.; Kniveton, D.; Layberry, R.

    2009-04-01

    It is increasingly accepted that that any possible climate change will not only have an influence on mean climate but may also significantly alter climatic variability. A change in the distribution and magnitude of extreme rainfall events (associated with changing variability), such as droughts or flooding, may have a far greater impact on human and natural systems than a changing mean. This issue is of particular importance for environmentally vulnerable regions such as southern Africa. The subcontinent is considered especially vulnerable to and ill-equipped (in terms of adaptation) for extreme events, due to a number of factors including extensive poverty, famine, disease and political instability. Rainfall variability and the identification of rainfall extremes is a function of scale, so high spatial and temporal resolution data are preferred to identify extreme events and accurately predict future variability. The majority of previous climate model verification studies have compared model output with observational data at monthly timescales. In this research, the assessment of ability of a state of the art climate model to simulate climate at daily timescales is carried out using satellite derived rainfall data from the Microwave Infra-Red Algorithm (MIRA). This dataset covers the period from 1993-2002 and the whole of southern Africa at a spatial resolution of 0.1 degree longitude/latitude. The ability of a climate model to simulate current climate provides some indication of how much confidence can be applied to its future predictions. In this paper, simulations of current climate from the UK Meteorological Office Hadley Centre's climate model, in both regional and global mode, are firstly compared to the MIRA dataset at daily timescales. This concentrates primarily on the ability of the model to simulate the spatial and temporal patterns of rainfall variability over southern Africa. Secondly, the ability of the model to reproduce daily rainfall extremes will

  17. Stochastic trajectories of succession initiated by extreme climatic events.

    PubMed

    Kreyling, J; Jentsch, A; Beierkuhnlein, C

    2011-08-01

    Deterministic or rule-based succession is expected under homogeneous biotic and abiotic starting conditions. Effects of extreme climatic events such as drought, however, may alter these assembly rules by adding stochastic elements. We monitored the succession of species composition of 30 twin grassland communities with identical biotic and abiotic starting conditions in an initially sown diversity gradient between 1 and 16 species over 13 years. The stochasticity of succession, measured as the synchrony in the development of the species compositions of the twin plots, was strongly altered by the extreme warm and dry summer of 2003. Moreover, it was independent from past and present plant diversity and neighbourhood species compositions. Extreme climatic events can induce stochastic effects in community development and therefore impair predictability even under homogeneous abiotic conditions. Stochastic events may result in lasting shifts of community composition, as well as adverse and unforeseeable effects on the stability of ecological services.

  18. Interactions of Mean Climate Change and Climate Variability on Food Security Extremes

    NASA Technical Reports Server (NTRS)

    Ruane, Alexander C.; McDermid, Sonali; Mavromatis, Theodoros; Hudson, Nicholas; Morales, Monica; Simmons, John; Prabodha, Agalawatte; Ahmad, Ashfaq; Ahmad, Shakeel; Ahuja, Laj R.

    2015-01-01

    Recognizing that climate change will affect agricultural systems both through mean changes and through shifts in climate variability and associated extreme events, we present preliminary analyses of climate impacts from a network of 1137 crop modeling sites contributed to the AgMIP Coordinated Climate-Crop Modeling Project (C3MP). At each site sensitivity tests were run according to a common protocol, which enables the fitting of crop model emulators across a range of carbon dioxide, temperature, and water (CTW) changes. C3MP can elucidate several aspects of these changes and quantify crop responses across a wide diversity of farming systems. Here we test the hypothesis that climate change and variability interact in three main ways. First, mean climate changes can affect yields across an entire time period. Second, extreme events (when they do occur) may be more sensitive to climate changes than a year with normal climate. Third, mean climate changes can alter the likelihood of climate extremes, leading to more frequent seasons with anomalies outside of the expected conditions for which management was designed. In this way, shifts in climate variability can result in an increase or reduction of mean yield, as extreme climate events tend to have lower yield than years with normal climate.C3MP maize simulations across 126 farms reveal a clear indication and quantification (as response functions) of mean climate impacts on mean yield and clearly show that mean climate changes will directly affect the variability of yield. Yield reductions from increased climate variability are not as clear as crop models tend to be less sensitive to dangers on the cool and wet extremes of climate variability, likely underestimating losses from water-logging, floods, and frosts.

  19. Effects of Extreme Climate on Mediterranean Societies

    NASA Astrophysics Data System (ADS)

    Xoplaki, Elena

    2009-04-01

    Climate Extremes During Recent Millennia and Their Impact on Mediterranean Societies; Athens, Greece, 13-16 September 2008; Climatic extremes in the past few thousand years have severely affected societies throughout the Mediterranean region and have changed the outcome of historical events in some instances. Climatic extremes—droughts, floods, prolonged cold and heat—affect society in a variety of ways, operating through famine, disease, and social upheaval. These topics were discussed at an interdisciplinary symposium at the National and Kapodistrian University, in Greece, that brought together climatologists, paleoclimatologists, anthropologists, geologists, archaeologists, and historians working in the greater Mediterranean region.

  20. Extreme climatic events in a changing climate: a review

    NASA Astrophysics Data System (ADS)

    Beniston, M.

    2003-04-01

    While changes in the long-term mean state of climate will have many important consequences on numerous environmental, social, and economic sectors, the most significant impacts of climatic change are likely to come about from shifts in the intensity and frequency of extreme weather events. Indeed, insurance costs resulting from extreme weather events have been steadily increasing over the last two decades, in response to both population pressures in regions that are at risk, but also because of the frequency and severity of certain forms of extremes. Regions now safe from catastrophic wind storms, heat waves, and floods could suddenly become vulnerable. The associated damage costs would consequently be extremely high. It seems appropriate, therefore, considering the environmental, human and economic costs exerted by extreme climatic events, to address the problem of whether there may be significant shifts in extremes of wind, precipitation or temperature in a changing global climate. In order to achieve these goals, the level of current scientific understanding and the availability of computational resources now enable numerical modeling techniques to be applied to this problem area. Examples will be given of particular numerical simulations of extreme events that have affected Western Europe and the alpine region in recent years. These simulations and impacts studies will be compared to observed events and trends during the 20th century, where adequate data is available to assess the manner in which certain forms of extreme events have changed, in part as a response to the global warming observed over the last 100 years.

  1. Historical influence of irrigation on climate extremes

    NASA Astrophysics Data System (ADS)

    Thiery, Wim; Davin, Edouard L.; Lawrence, Dave; Hauser, Mathias; Seneviratne, Sonia I.

    2016-04-01

    Land irrigation is an essential practice sustaining global food production and many regional economies. During the last decades, irrigation amounts have been growing rapidly. Emerging scientific evidence indicates that land irrigation substantially affects mean climate conditions in different regions of the world. However, a thorough understanding of the impact of irrigation on extreme climatic conditions, such as heat waves, droughts or intense precipitation, is currently still lacking. In this context, we aim to assess the historical influence of irrigation on the occurrence of climate extremes. To this end, two simulations are conducted over the period 1910-2010 with a state-of-the-art global climate model (the Community Earth System Model, CESM): a control simulation including all major anthropogenic and natural external forcings except for irrigation and a second experiment with transient irrigation enabled. The two simulations are evaluated for their ability to represent (i) hot, dry and wet extremes using the HadEX2 and ERA-Interim datasets as a reference, and (ii) latent heat fluxes using LandFlux-EVAL. Assuming a linear combination of climatic responses to different forcings, the difference between both experiments approximates the influence of irrigation. We will analyse the impact of irrigation on a number of climate indices reflecting the intensity and duration of heat waves. Thereby, particular attention is given to the role of soil moisture changes in modulating climate extremes. Furthermore, the contribution of individual biogeophysical processes to the total impact of irrigation on hot extremes is quantified by application of a surface energy balance decomposition technique to the 90th and 99th percentile surface temperature changes.

  2. Climate extremes in the amazon basin

    NASA Astrophysics Data System (ADS)

    Marengo, José; Mendes, David

    2010-05-01

    Changes in extreme weather and climate events have significant impacts and are among the most serious challenges to society in coping with a changing climate (CCSP, 2008). Indeed, according to IPCC AR4, confidence has increased that some extremes will become more frequent, more widespread and/or more intense during the 21st century . Until recently, there had been little published work on rainfall extremes in South America, and emphasis has been given to the La Plata Basin, where data coverage is much better. In this study, we use the indices of extremes derived by the WMO and used for the IPCC AR4 applied to 100 stations in Amazon Basin for the period from 1971 to 2005, with focus on rainfall extremes. The quality control involved carefully evaluating numerous detailed graphs of daily data to detect evidence of possible quality issues with the data as well as statistically identifying outliers. Each outlier or potential data problem was manually validated using metadata information of our climate data.

  3. An 'extreme' future for estuaries? Effects of extreme climatic events on estuarine water quality and ecology.

    PubMed

    Wetz, Michael S; Yoskowitz, David W

    2013-04-15

    Recent climate observations suggest that extreme climatic events (ECE; droughts, floods, tropical cyclones, heat waves) have increased in frequency and/or intensity in certain world regions, consistent with climate model projections that account for man's influence on the global climate system. A synthesis of existing literature is presented and shows that ECE affect estuarine water quality by altering: (1) the delivery and processing of nutrients and organic matter, (2) physical-chemical properties of estuaries, and (3) ecosystem structure and function. From the standpoint of estuarine scientists and resource managers, a major scientific challenge will be to project the estuarine response to ECE that will co-occur with other important environmental changes (i.e., natural climate variability, global warming, sea level rise, eutrophication), as this will affect the provisioning of important ecosystem services provided by estuaries.

  4. Extreme Weather in a Changing Climate

    NASA Astrophysics Data System (ADS)

    Wuebbles, D. J.

    2015-12-01

    It is a real honor for me to get the opportunity to pay homage to Steve Schneider and his extensive accomplishments. I also treasured his friendship. Steve was known for being a great communicator and for his expertise in climate policy and solutions, along with being an outstanding scientist with many contributions to understanding the Earth's climate system. One of the major challenges today to all of these areas is the changing trends in extreme weather under a changing climate. My focus in this presentation is to examine these issues by drawing on new research from my own team at Illinois. For example, climate change amplification in the Arctic has raised questions regarding its potential effects on extreme weather at mid-latitudes, especially the United States. In our studies, we find a statistically significant relationship between summer sea ice north of Alaska and geopotential height anomalies in the north Pacific during subsequent winter and spring months. The frequency of these semi-persistent height anomalies exhibits a long-term upward trend that amplify the jet stream off the West Coast of the U.S., driving more persistent precipitation patterns over certain regions of the United States, specifically in the West and Midwest parts of the country. Our results suggest that as sea ice in the Arctic north of Alaska continues to decrease, a more persistent ridge will form in areas adjacent to this location and affect storm tracks over the continental United States. In other studies, we are examining the effects of the changing climate on trends in extreme events throughout the continental U.S. We are also investigating changes in historical severe convective weather over the United States using reanalysis data, the NEXRAD/in situ gauge Climate Data Record (CDR) data set, and storm reports. After analyzing the ability of global climate models to represent the observed trends in severe-thunderstorm environments, projected future trends are also to be analyzed.

  5. Rainfall variability and extremes over southern Africa: Assessment of a climate model to reproduce daily extremes

    NASA Astrophysics Data System (ADS)

    Williams, C. J. R.; Kniveton, D. R.; Layberry, R.

    2009-04-01

    It is increasingly accepted that that any possible climate change will not only have an influence on mean climate but may also significantly alter climatic variability. A change in the distribution and magnitude of extreme rainfall events (associated with changing variability), such as droughts or flooding, may have a far greater impact on human and natural systems than a changing mean. This issue is of particular importance for environmentally vulnerable regions such as southern Africa. The subcontinent is considered especially vulnerable to and ill-equipped (in terms of adaptation) for extreme events, due to a number of factors including extensive poverty, famine, disease and political instability. Rainfall variability and the identification of rainfall extremes is a function of scale, so high spatial and temporal resolution data are preferred to identify extreme events and accurately predict future variability. The majority of previous climate model verification studies have compared model output with observational data at monthly timescales. In this research, the assessment of ability of a state of the art climate model to simulate climate at daily timescales is carried out using satellite derived rainfall data from the Microwave Infra-Red Algorithm (MIRA). This dataset covers the period from 1993-2002 and the whole of southern Africa at a spatial resolution of 0.1 degree longitude/latitude. The ability of a climate model to simulate current climate provides some indication of how much confidence can be applied to its future predictions. In this paper, simulations of current climate from the UK Meteorological Office Hadley Centre's climate model, in both regional and global mode, are firstly compared to the MIRA dataset at daily timescales. This concentrates primarily on the ability of the model to simulate the spatial and temporal patterns of rainfall variability over southern Africa. Secondly, the ability of the model to reproduce daily rainfall extremes will

  6. Microhabitats reduce animal's exposure to climate extremes.

    PubMed

    Scheffers, Brett R; Edwards, David P; Diesmos, Arvin; Williams, Stephen E; Evans, Theodore A

    2014-02-01

    Extreme weather events, such as unusually hot or dry conditions, can cause death by exceeding physiological limits, and so cause loss of population. Survival will depend on whether or not susceptible organisms can find refuges that buffer extreme conditions. Microhabitats offer different microclimates to those found within the wider ecosystem, but do these microhabitats effectively buffer extreme climate events relative to the physiological requirements of the animals that frequent them? We collected temperature data from four common microhabitats (soil, tree holes, epiphytes, and vegetation) located from the ground to canopy in primary rainforests in the Philippines. Ambient temperatures were monitored from outside of each microhabitat and from the upper forest canopy, which represent our macrohabitat controls. We measured the critical thermal maxima (CTmax ) of frog and lizard species, which are thermally sensitive and inhabit our microhabitats. Microhabitats reduced mean temperature by 1-2 °C and reduced the duration of extreme temperature exposure by 14-31 times. Microhabitat temperatures were below the CTmax of inhabitant frogs and lizards, whereas macrohabitats consistently contained lethal temperatures. Microhabitat temperatures increased by 0.11-0.66 °C for every 1 °C increase in macrohabitat temperature, and this nonuniformity in temperature change influenced our forecasts of vulnerability for animal communities under climate change. Assuming uniform increases of 6 °C, microhabitats decreased the vulnerability of communities by up to 32-fold, whereas under nonuniform increases of 0.66 to 3.96 °C, microhabitats decreased the vulnerability of communities by up to 108-fold. Microhabitats have extraordinary potential to buffer climate and likely reduce mortality during extreme climate events. These results suggest that predicted changes in distribution due to mortality and habitat shifts that are derived from macroclimatic samples and that assume

  7. Precipitation extremes with climate variability and change

    NASA Astrophysics Data System (ADS)

    Ganguly, A. R.

    2011-12-01

    Significant gaps exist in our understanding of hydro-meteorological processes in the context of climate variability or change. However, despite the uncertainties, developing relatively credible insights for precipitation extremes at scales relevant for hydrology is necessary and may be possible. Statistical analyses of observed and model-simulated precipitation data, particularly methods based on extreme value theory, have demonstrated the potential to yield new insights. Specifically, a delineation of the impacts of global climate change versus regional changes in land use or urbanization may be possible and could be important for policy-makers. Precipitation extremes have known dependence on variables like sea surface temperatures, atmospheric temperature profiles and wind velocities, some of which may be better predicted than precipitation from models, exhibit less variability in observations and may not be as subject to thresholds and intermittences in either models or observations. Thus, leveraging the information content in these auxiliary variables through data mining or network science based approaches, especially if the techniques are informed by process understanding at multiple scales, may help improve regional projections of precipitation and corresponding extremes. Enhanced regional projections of precipitation and their extremes can help drive models of hydrology and hence better inform water managers, especially at scales that matter for water resources planning or managing hydraulic infrastructures. A combination of physics-based models, data-guided mathematical approaches, and quantitative techniques informed by conceptual process understanding, may be a way forward to understand the possible consequences of climate variability and global or regional change on precipitation extremes. Examples and case studies are presented from the published literature and from ongoing research.

  8. Impacts of Irrigation on Daily Extremes in the Coupled Climate System

    NASA Technical Reports Server (NTRS)

    Puma, Michael J.; Cook, Benjamin I.; Krakauer, Nir; Gentine, Pierre; Nazarenka, Larissa; Kelly, Maxwell; Wada, Yoshihide

    2014-01-01

    Widespread irrigation alters regional climate through changes to the energy and water budgets of the land surface. Within general circulation models, simulation studies have revealed significant changes in temperature, precipitation, and other climate variables. Here we investigate the feedbacks of irrigation with a focus on daily extremes at the global scale. We simulate global climate for the year 2000 with and without irrigation to understand irrigation-induced changes. Our simulations reveal shifts in key climate-extreme metrics. These findings indicate that land cover and land use change may be an important contributor to climate extremes both locally and in remote regions including the low-latitudes.

  9. On the response of European phenology to Extreme Climate Events

    NASA Astrophysics Data System (ADS)

    Guido, C.; Gobron, N.

    2012-12-01

    Extreme Climate Events are expected to alter carbon cycle processes, with implications for ecosystems and feedback to regional and global climate. Hence, understanding the interactions between Extreme Climate Events and vegetation dynamics is essential for improved climate prediction. In this work, the authors analyze carbon cycle dynamics over the European domain using Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) derived from Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data (1997-2002) and MERIS (2003-2011) at ~1 km resolution. As part of this analysis, six phenological metrics were defined from FAPAR measurement to characterize the ecosystem response to climate and anthropogenic forcing at the land surface. Based on phenological metrics analysis, the inter-annual vegetation variations, their dependence on drought and heat waves, and the presence of long-term trends were detected. In addition, the authors have assessed Rain Use Efficiency (RUE), represented by the ratio of annual sum FAPAR and annual rainfall, and the correlation between FAPAR, precipitation and temperature anomalies over the same time period. Climate anomalies largely explain the recent anomalies of FAPAR- and consequently of carbon cycle. Hence, well-defined large scale patterns of RUE and phenological metrics are discernible: the large scale drought that struck Europe in year 2003 has a distinct signature, as well as the continuous positive anomaly during summer 2002 (due to intense rainfall) is well-depicted.

  10. Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts.

    PubMed

    Frank, Dorothea; Reichstein, Markus; Bahn, Michael; Thonicke, Kirsten; Frank, David; Mahecha, Miguel D; Smith, Pete; van der Velde, Marijn; Vicca, Sara; Babst, Flurin; Beer, Christian; Buchmann, Nina; Canadell, Josep G; Ciais, Philippe; Cramer, Wolfgang; Ibrom, Andreas; Miglietta, Franco; Poulter, Ben; Rammig, Anja; Seneviratne, Sonia I; Walz, Ariane; Wattenbach, Martin; Zavala, Miguel A; Zscheischler, Jakob

    2015-08-01

    Extreme droughts, heat waves, frosts, precipitation, wind storms and other climate extremes may impact the structure, composition and functioning of terrestrial ecosystems, and thus carbon cycling and its feedbacks to the climate system. Yet, the interconnected avenues through which climate extremes drive ecological and physiological processes and alter the carbon balance are poorly understood. Here, we review the literature on carbon cycle relevant responses of ecosystems to extreme climatic events. Given that impacts of climate extremes are considered disturbances, we assume the respective general disturbance-induced mechanisms and processes to also operate in an extreme context. The paucity of well-defined studies currently renders a quantitative meta-analysis impossible, but permits us to develop a deductive framework for identifying the main mechanisms (and coupling thereof) through which climate extremes may act on the carbon cycle. We find that ecosystem responses can exceed the duration of the climate impacts via lagged effects on the carbon cycle. The expected regional impacts of future climate extremes will depend on changes in the probability and severity of their occurrence, on the compound effects and timing of different climate extremes, and on the vulnerability of each land-cover type modulated by management. Although processes and sensitivities differ among biomes, based on expert opinion, we expect forests to exhibit the largest net effect of extremes due to their large carbon pools and fluxes, potentially large indirect and lagged impacts, and long recovery time to regain previous stocks. At the global scale, we presume that droughts have the strongest and most widespread effects on terrestrial carbon cycling. Comparing impacts of climate extremes identified via remote sensing vs. ground-based observational case studies reveals that many regions in the (sub-)tropics are understudied. Hence, regional investigations are needed to allow a global

  11. Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts

    PubMed Central

    Frank, Dorothea; Reichstein, Markus; Bahn, Michael; Thonicke, Kirsten; Frank, David; Mahecha, Miguel D; Smith, Pete; van der Velde, Marijn; Vicca, Sara; Babst, Flurin; Beer, Christian; Buchmann, Nina; Canadell, Josep G; Ciais, Philippe; Cramer, Wolfgang; Ibrom, Andreas; Miglietta, Franco; Poulter, Ben; Rammig, Anja; Seneviratne, Sonia I; Walz, Ariane; Wattenbach, Martin; Zavala, Miguel A; Zscheischler, Jakob

    2015-01-01

    Extreme droughts, heat waves, frosts, precipitation, wind storms and other climate extremes may impact the structure, composition and functioning of terrestrial ecosystems, and thus carbon cycling and its feedbacks to the climate system. Yet, the interconnected avenues through which climate extremes drive ecological and physiological processes and alter the carbon balance are poorly understood. Here, we review the literature on carbon cycle relevant responses of ecosystems to extreme climatic events. Given that impacts of climate extremes are considered disturbances, we assume the respective general disturbance-induced mechanisms and processes to also operate in an extreme context. The paucity of well-defined studies currently renders a quantitative meta-analysis impossible, but permits us to develop a deductive framework for identifying the main mechanisms (and coupling thereof) through which climate extremes may act on the carbon cycle. We find that ecosystem responses can exceed the duration of the climate impacts via lagged effects on the carbon cycle. The expected regional impacts of future climate extremes will depend on changes in the probability and severity of their occurrence, on the compound effects and timing of different climate extremes, and on the vulnerability of each land-cover type modulated by management. Although processes and sensitivities differ among biomes, based on expert opinion, we expect forests to exhibit the largest net effect of extremes due to their large carbon pools and fluxes, potentially large indirect and lagged impacts, and long recovery time to regain previous stocks. At the global scale, we presume that droughts have the strongest and most widespread effects on terrestrial carbon cycling. Comparing impacts of climate extremes identified via remote sensing vs. ground-based observational case studies reveals that many regions in the (sub-)tropics are understudied. Hence, regional investigations are needed to allow a global

  12. Detecting Extreme Events in Gridded Climate Data

    SciTech Connect

    Ramachandra, Bharathkumar; Gadiraju, Krishna; Vatsavai, Raju; Kaiser, Dale Patrick; Karnowski, Thomas Paul

    2016-01-01

    Detecting and tracking extreme events in gridded climatological data is a challenging problem on several fronts: algorithms, scalability, and I/O. Successful detection of these events will give climate scientists an alternate view of the behavior of different climatological variables, leading to enhanced scientific understanding of the impacts of events such as heat and cold waves, and on a larger scale, the El Nin o Southern Oscillation. Recent advances in computing power and research in data sciences enabled us to look at this problem with a different perspective from what was previously possible. In this paper we present our computationally efficient algorithms for anomalous cluster detection on climate change big data. We provide results on detection and tracking of surface temperature and geopotential height anomalies, a trend analysis, and a study of relationships between the variables. We also identify the limitations of our approaches, future directions for research and alternate approaches.

  13. Improving the Accuracy of Estimation of Climate Extremes

    NASA Astrophysics Data System (ADS)

    Zolina, Olga; Detemmerman, Valery; Trenberth, Kevin E.

    2010-12-01

    Workshop on Metrics and Methodologies of Estimation of Extreme Climate Events; Paris, France, 27-29 September 2010; Climate projections point toward more frequent and intense weather and climate extremes such as heat waves, droughts, and floods, in a warmer climate. These projections, together with recent extreme climate events, including flooding in Pakistan and the heat wave and wildfires in Russia, highlight the need for improved risk assessments to help decision makers and the public. But accurate analysis and prediction of risk of extreme climate events require new methodologies and information from diverse disciplines. A recent workshop sponsored by the World Climate Research Programme (WCRP) and hosted at United Nations Educational, Scientific and Cultural Organization (UNESCO) headquarters in France brought together, for the first time, a unique mix of climatologists, statisticians, meteorologists, oceanographers, social scientists, and risk managers (such as those from insurance companies) who sought ways to improve scientists' ability to characterize and predict climate extremes in a changing climate.

  14. Is climate change modifying precipitation extremes?

    NASA Astrophysics Data System (ADS)

    Montanari, Alberto; Papalexiou, Simon Michael

    2016-04-01

    The title of the present contribution is a relevant question that is frequently posed to scientists, technicians and managers of local authorities. Although several research efforts were recently dedicated to rainfall observation, analysis and modelling, the above question remains essentially unanswered. The question comes from the awareness that the frequency of floods and the related socio-economic impacts are increasing in many countries, and climate change is deemed to be the main trigger. Indeed, identifying the real reasons for the observed increase of flood risk is necessary in order to plan effective mitigation and adaptation strategies. While mitigation of climate change is an extremely important issue at the global level, at small spatial scales several other triggers may interact with it, therefore requiring different mitigation strategies. Similarly, the responsibilities of administrators are radically different at local and global scales. This talk aims to provide insights and information to address the question expressed by its title. High resolution and long term rainfall data will be presented, as well as an analysis of the frequency of their extremes and its progress in time. The results will provide pragmatic indications for the sake of better planning flood risk mitigation policies.

  15. Impact of climatic extremity upon human health

    SciTech Connect

    Miah, M.A.; Samad, M.A.

    1997-12-31

    The extreme climate generated in the wake of the shortage of the supply of natural water in the lower Ganges basin has triggered a number of environmental diseases in the lower Ganges basin. In the wake of improper sanitation conditions for the scarcity of water, water-borne diseases like cholera, diarrhea, hepatitis, etc., break out and take out the lives of victims. Further, the development of the dry climate has favored an increased amount of suspended particulate matter in the air. The result is the prevalent problem of asthma which is even worse than the water-borne diseases. Almost one in every four families living in this city has an asthma patient. The worst is that more than 10% of the families have three asthma patients. And, most of the elderly asthma patients suffer from diabetes and high blood pressure at the same time. The wide spread of asthma is thought to be related to the triggering allergic action suffered by patients due to the presence of excess particulate matter in the air. More than 50% of the population suffer from nasal allergy, sinusitis, and chronic bronchitis. The suspended particles are mostly fine grains of sands and carbon. The cleanest air (usually, after a heavy rainfall) contains at least one gm of particulate matter in every 2,039 cubic meter of air. An average man will inhale about 1.11 million gallons of air per year which amounts to about 2 gm of particulate matter per year. Additionally, during the dry months, major duststorms appear a couple of times with an uplift of half a million kg of dust in air over about 810 square km each time. The paper will focus on water scarcity, the climatic extremity, suspended particulate matter, the outbreaks of water-borne and the prevalent respiratory diseases, and suggestions to mitigate human sufferings.

  16. Climate Teleconnections, Weather Extremes, and Vector-Borne Disease Outbreaks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fluctuations in climate lead to extremes in temperature, rainfall, flooding, and droughts. These climate extremes create ideal ecological conditions that promote mosquito-borne disease transmission that impact global human and animal health. One well known driver of such global scale climate fluctua...

  17. Altered States of Consciousness during an Extreme Ritual.

    PubMed

    Lee, Ellen M; Klement, Kathryn R; Ambler, James K; Loewald, Tonio; Comber, Evelyn M; Hanson, Sarah A; Pruitt, Bria; Sagarin, Brad J

    2016-01-01

    Extreme rituals (body-piercing, fire-walking, etc.) are anecdotally associated with altered states of consciousness-subjective alterations of ordinary mental functioning (Ward, 1984)-but empirical evidence of altered states using both direct and indirect measures during extreme rituals in naturalistic settings is limited. Participants in the "Dance of Souls", a 3.5-hour event during which participants received temporary piercings with hooks or weights attached to the piercings and danced to music provided by drummers, responded to measures of two altered states of consciousness. Participants also completed measures of positive and negative affect, salivary cortisol (a hormone associated with stress), self-reported stress, sexual arousal, and intimacy. Both pierced participants (pierced dancers) and non-pierced participants (piercers, piercing assistants, observers, drummers, and event leaders) showed evidence of altered states aligned with transient hypofrontality (Dietrich, 2003; measured with a Stroop test) and flow (Csikszentmihalyi, 1990; Csikszentmihalyi & Csikszentmihalyi, 1990; measured with the Flow State Scale). Both pierced and non-pierced participants also reported decreases in negative affect and psychological stress and increases in intimacy from before to after the ritual. Pierced and non-pierced participants showed different physiological reactions, however, with pierced participants showing increases in cortisol and non-pierced participants showing decreases from before to during the ritual. Overall, the ritual appeared to induce different physiological effects but similar psychological effects in focal ritual participants (i.e., pierced dancers) and in participants adopting other roles. PMID:27175897

  18. Altered States of Consciousness during an Extreme Ritual

    PubMed Central

    Loewald, Tonio; Comber, Evelyn M.; Hanson, Sarah A.; Pruitt, Bria

    2016-01-01

    Extreme rituals (body-piercing, fire-walking, etc.) are anecdotally associated with altered states of consciousness—subjective alterations of ordinary mental functioning (Ward, 1984)—but empirical evidence of altered states using both direct and indirect measures during extreme rituals in naturalistic settings is limited. Participants in the “Dance of Souls”, a 3.5-hour event during which participants received temporary piercings with hooks or weights attached to the piercings and danced to music provided by drummers, responded to measures of two altered states of consciousness. Participants also completed measures of positive and negative affect, salivary cortisol (a hormone associated with stress), self-reported stress, sexual arousal, and intimacy. Both pierced participants (pierced dancers) and non-pierced participants (piercers, piercing assistants, observers, drummers, and event leaders) showed evidence of altered states aligned with transient hypofrontality (Dietrich, 2003; measured with a Stroop test) and flow (Csikszentmihalyi, 1990; Csikszentmihalyi & Csikszentmihalyi, 1990; measured with the Flow State Scale). Both pierced and non-pierced participants also reported decreases in negative affect and psychological stress and increases in intimacy from before to after the ritual. Pierced and non-pierced participants showed different physiological reactions, however, with pierced participants showing increases in cortisol and non-pierced participants showing decreases from before to during the ritual. Overall, the ritual appeared to induce different physiological effects but similar psychological effects in focal ritual participants (i.e., pierced dancers) and in participants adopting other roles. PMID:27175897

  19. Climatic extremes improve predictions of spatial patterns of tree species

    USGS Publications Warehouse

    Zimmermann, N.E.; Yoccoz, N.G.; Edwards, T.C.; Meier, E.S.; Thuiller, W.; Guisan, A.; Schmatz, D.R.; Pearman, P.B.

    2009-01-01

    Understanding niche evolution, dynamics, and the response of species to climate change requires knowledge of the determinants of the environmental niche and species range limits. Mean values of climatic variables are often used in such analyses. In contrast, the increasing frequency of climate extremes suggests the importance of understanding their additional influence on range limits. Here, we assess how measures representing climate extremes (i.e., interannual variability in climate parameters) explain and predict spatial patterns of 11 tree species in Switzerland. We find clear, although comparably small, improvement (+20% in adjusted D2, +8% and +3% in cross-validated True Skill Statistic and area under the receiver operating characteristics curve values) in models that use measures of extremes in addition to means. The primary effect of including information on climate extremes is a correction of local overprediction and underprediction. Our results demonstrate that measures of climate extremes are important for understanding the climatic limits of tree species and assessing species niche characteristics. The inclusion of climate variability likely will improve models of species range limits under future conditions, where changes in mean climate and increased variability are expected.

  20. Interpreting the Climatic Effects on Xylem Functional Traits in Two Mediterranean Oak Species: The Role of Extreme Climatic Events.

    PubMed

    Rita, Angelo; Borghetti, Marco; Todaro, Luigi; Saracino, Antonio

    2016-01-01

    In the Mediterranean region, the widely predicted rise in temperature, change in the precipitation pattern, and increase in the frequency of extreme climatic events are expected to alter the shape of ecological communities and to affect plant physiological processes that regulate ecosystem functioning. Although change in the mean values are important, there is increasing evidence that plant distribution, survival, and productivity respond to extremes rather than to the average climatic condition. The present study aims to assess the effects of both mean and extreme climatic conditions on radial growth and functional anatomical traits using long-term tree-ring time series of two co-existing Quercus spp. from a drought-prone site in Southern Italy. In particular, this is the first attempt to apply the Generalized Additive Model for Location, Scale, and Shape (GAMLSS) technique and Bayesian modeling procedures to xylem traits data set, with the aim of (i) detecting non-linear long-term responses to climate and (ii) exploring relationships between climate extreme and xylem traits variability in terms of probability of occurrence. This study demonstrates the usefulness of long-term xylem trait chronologies as records of environmental conditions at annual resolution. Statistical analyses revealed that most of the variability in tree-ring width and specific hydraulic conductivity might be explained by cambial age. Additionally, results highlighted appreciable relationships between xylem traits and climate variability more than tree-ring width, supporting also the evidence that the plant hydraulic traits are closely linked to local climate extremes rather than average climatic conditions. We reported that the probability of extreme departure in specific hydraulic conductivity (Ks) rises at extreme values of Standardized Precipitation Index (SPI). Therefore, changing frequency or intensity of extreme events might overcome the adaptive limits of vascular transport, resulting

  1. Interpreting the Climatic Effects on Xylem Functional Traits in Two Mediterranean Oak Species: The Role of Extreme Climatic Events.

    PubMed

    Rita, Angelo; Borghetti, Marco; Todaro, Luigi; Saracino, Antonio

    2016-01-01

    In the Mediterranean region, the widely predicted rise in temperature, change in the precipitation pattern, and increase in the frequency of extreme climatic events are expected to alter the shape of ecological communities and to affect plant physiological processes that regulate ecosystem functioning. Although change in the mean values are important, there is increasing evidence that plant distribution, survival, and productivity respond to extremes rather than to the average climatic condition. The present study aims to assess the effects of both mean and extreme climatic conditions on radial growth and functional anatomical traits using long-term tree-ring time series of two co-existing Quercus spp. from a drought-prone site in Southern Italy. In particular, this is the first attempt to apply the Generalized Additive Model for Location, Scale, and Shape (GAMLSS) technique and Bayesian modeling procedures to xylem traits data set, with the aim of (i) detecting non-linear long-term responses to climate and (ii) exploring relationships between climate extreme and xylem traits variability in terms of probability of occurrence. This study demonstrates the usefulness of long-term xylem trait chronologies as records of environmental conditions at annual resolution. Statistical analyses revealed that most of the variability in tree-ring width and specific hydraulic conductivity might be explained by cambial age. Additionally, results highlighted appreciable relationships between xylem traits and climate variability more than tree-ring width, supporting also the evidence that the plant hydraulic traits are closely linked to local climate extremes rather than average climatic conditions. We reported that the probability of extreme departure in specific hydraulic conductivity (Ks) rises at extreme values of Standardized Precipitation Index (SPI). Therefore, changing frequency or intensity of extreme events might overcome the adaptive limits of vascular transport, resulting

  2. Interpreting the Climatic Effects on Xylem Functional Traits in Two Mediterranean Oak Species: The Role of Extreme Climatic Events

    PubMed Central

    Rita, Angelo; Borghetti, Marco; Todaro, Luigi; Saracino, Antonio

    2016-01-01

    In the Mediterranean region, the widely predicted rise in temperature, change in the precipitation pattern, and increase in the frequency of extreme climatic events are expected to alter the shape of ecological communities and to affect plant physiological processes that regulate ecosystem functioning. Although change in the mean values are important, there is increasing evidence that plant distribution, survival, and productivity respond to extremes rather than to the average climatic condition. The present study aims to assess the effects of both mean and extreme climatic conditions on radial growth and functional anatomical traits using long-term tree-ring time series of two co-existing Quercus spp. from a drought-prone site in Southern Italy. In particular, this is the first attempt to apply the Generalized Additive Model for Location, Scale, and Shape (GAMLSS) technique and Bayesian modeling procedures to xylem traits data set, with the aim of (i) detecting non-linear long-term responses to climate and (ii) exploring relationships between climate extreme and xylem traits variability in terms of probability of occurrence. This study demonstrates the usefulness of long-term xylem trait chronologies as records of environmental conditions at annual resolution. Statistical analyses revealed that most of the variability in tree-ring width and specific hydraulic conductivity might be explained by cambial age. Additionally, results highlighted appreciable relationships between xylem traits and climate variability more than tree-ring width, supporting also the evidence that the plant hydraulic traits are closely linked to local climate extremes rather than average climatic conditions. We reported that the probability of extreme departure in specific hydraulic conductivity (Ks) rises at extreme values of Standardized Precipitation Index (SPI). Therefore, changing frequency or intensity of extreme events might overcome the adaptive limits of vascular transport, resulting

  3. Extreme hydrometeorological events and climate change predictions in Europe

    NASA Astrophysics Data System (ADS)

    Millán, Millán M.

    2014-10-01

    Field meteorological data collected in several European Commission projects (from 1974 to 2011) were re-analysed in the context of a perceived reduction in summer storms around the Western Mediterranean Basin (WMB). The findings reveal some hitherto overlooked processes that raise questions about direct impacts on European hydrological cycles, e.g., extreme hydrometeorological events, and about the role of feedbacks on climate models and climate predictions. For instance, the summer storms are affected by land-use changes along the coasts and mountain slopes. Their loss triggers a chain of events that leads to an Accumulation Mode (AM) where water vapour and air pollutants (ozone) become stacked in layers, up to 4000(+) m, over the WMB. The AM cycle can last 3-5 consecutive days, and recur several times each month from mid May to late August. At the end of each cycle the accumulated water vapour can feed Vb track events and generate intense rainfall and summer floods in Central Europe. Venting out of the water vapour that should have precipitated within the WMB increases the salinity of the sea and affects the Atlantic-Mediterranean Salinity valve at Gibraltar. This, in turn, can alter the tracks of Atlantic Depressions and their frontal systems over Atlantic Europe. Another effect is the greenhouse heating by water vapour and photo-oxidants (e.g., O3) when layered over the Basin during the AM cycle. This increases the Sea Surface Temperature (SST), and the higher SST intensifies torrential rain events over the Mediterranean coasts in autumn. All these processes raise research questions that must be addressed to improve the meteorological forecasting of extreme events, as well as climate model predictions.

  4. Public perceptions of climate change and extreme weather events

    NASA Astrophysics Data System (ADS)

    Bruine de Bruin, W.; Dessai, S.; Morgan, G.; Taylor, A.; Wong-Parodi, G.

    2013-12-01

    Climate experts face a serious communication challenge. Public debate about climate change continues, even though at the same time people seem to complain about extreme weather events becoming increasingly common. As compared to the abstract concept of ';climate change,' (changes in) extreme weather events are indeed easier to perceive, more vivid, and personally relevant. Public perception research in different countries has suggested that people commonly expect that climate change will lead to increases in temperature, and that unseasonably warm weather is likely to be interpreted as evidence of climate change. However, relatively little is known about whether public concerns about climate change may also be driven by changes in other types of extreme weather events, such as exceptional amounts of precipitation or flooding. We therefore examined how perceptions of and personal experiences with changes in these specific weather events are related to public concerns about climate change. In this presentation, we will discuss findings from two large public perception surveys conducted in flood-prone Pittsburgh, Pennsylvania (US) and with a national sample in the UK, where extreme flooding has recently occurred across the country. Participants completed questions about their perceptions of and experiences with specific extreme weather events, and their beliefs about climate change. We then conducted linear regressions to predict individual differences in climate-change beliefs, using perceptions of and experiences with specific extreme weather events as predictors, while controlling for demographic characteristics. The US study found that people (a) perceive flood chances to be increasing over the decades, (b) believe climate change to play a role in increases in future flood chances, and (c) would interpret future increases in flooding as evidence for climate change. The UK study found that (a) UK residents are more likely to perceive increases in ';wet' events such

  5. Combined effects of extreme climatic events and elevation on nutritional quality and herbivory of Alpine plants.

    PubMed

    Leingärtner, Annette; Hoiss, Bernhard; Krauss, Jochen; Steffan-Dewenter, Ingolf

    2014-01-01

    Climatic extreme events can cause the shift or disruption of plant-insect interactions due to altered plant quality, e.g. leaf carbon to nitrogen ratios, and phenology. However, the response of plant-herbivore interactions to extreme events and climatic gradients has been rarely studied, although climatic extremes will increase in frequency and intensity in the future and insect herbivores represent a highly diverse and functionally important group. We set up a replicated climate change experiment along elevational gradients in the German Alps to study the responses of three plant guilds and their herbivory by insects to extreme events (extreme drought, advanced and delayed snowmelt) versus control plots under different climatic conditions on 15 grassland sites. Our results indicate that elevational shifts in CN (carbon to nitrogen) ratios and herbivory depend on plant guild and season. CN ratios increased with altitude for grasses, but decreased for legumes and other forbs. In contrast to our hypotheses, extreme climatic events did not significantly affect CN ratios and herbivory. Thus, our study indicates that nutritional quality of plants and antagonistic interactions with insect herbivores are robust against seasonal climatic extremes. Across the three functional plant guilds, herbivory increased with nitrogen concentrations. Further, increased CN ratios indicate a reduction in nutritional plant quality with advancing season. Although our results revealed no direct effects of extreme climatic events, the opposing responses of plant guilds along elevation imply that competitive interactions within plant communities might change under future climates, with unknown consequences for plant-herbivore interactions and plant community composition.

  6. Biodiversity increases the resistance of ecosystem productivity to climate extremes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It remains unclear whether biodiversity buffers ecosystems against extreme climate events, which are becoming increasingly frequent worldwide. Although early results suggested that biodiversity might provide both resistance and resilience (sensu rapid recovery) of ecosystem productivity to drought, ...

  7. Climate change impacts on hydrological extremes in Central Europe

    NASA Astrophysics Data System (ADS)

    Fokko Hattermann, Fred; Huang, Shaochun; Kundzewicz, Zbigniew W.; Hoffmann, Peter

    2016-04-01

    An increase of hydro-climatic extremes can be observed worldwide and is challenging national and regional risk management and adaptation plans. Our study presents and discusses possible trends in climate drivers and hydro-climatic extremes in Europe observed and under future climate conditions. In a case study for Germany, impacts of different regional climate scenario ensembles are compared. To this end, a hydrological model was applied to transform the scenarios data into river runoff for more than 5000 river reaches in Germany. Extreme Value Distributions have been fitted to the hydrographs of the river reaches to derive the basic flood statistics. The results for each river reach have been linked to related damage functions as provided by the German Insurance Association considering damages on buildings and small enterprises. The robust result is that under scenario conditions a significant increase in flood related losses can be expected in Germany, while also the number of low flow events may rise.

  8. Extreme wind climate in the Czech Republic

    NASA Astrophysics Data System (ADS)

    Pop, L.; Hanslian, D.; Jiri, H.

    2011-12-01

    Extreme wind events belong to the most damaging weather-related hazards in Czech Republic. Therefore a complex survey is performed to exploit the wind data available over the period of industrial measurements in Czech Republic for extreme wind analysis. The object of the survey is to find the limitations of wind data available, to analyze the conditions for extreme wind events and to try to enhance the knowledge about the statistical behavior of extreme wind. The data quality showed itself as a major issue. The homogeneity of extreme wind data is broken in many cases as the extreme wind values are highly dependent on the measuring instrumentation and changes in neighborhood. It also may be difficult to distinguish between correct high wind data and erroneous values. The individual analysis and quality assessment of wind data used in extremal analysis is therefore essential. There are generally two basic groups of extreme wind events typical in the Czech Republic and generally over the mid-latitudes: The "convective" events (can be also called as "squalls") are primarily initiated by deep convection, whereas the primary cause for "non-convective" (synoptic) events is large-scale pressure gradient. The subject is, however, a bit more complex, as the pressure gradient inducing high wind in higher atmospheric levels or wind shear can be a significant factor in convective events; on the other hand, convection may increase wind speeds in otherwise "non-convective" synoptic-scale windstorms. In addition, there are some special phenomena that should be treated individually: the physical principle and climatological behavior (frequency, magnitude and area affected) of tornadoes make them very different from common convective straight winds; this is in lesser scale also the case of "foehn" or "bora" effects belonging to non-convective events. These effects, however, do not play major role over the Czech Republic. In Czech Republic, the overall impact of convective and non

  9. Integrating Science and Engineering to Reduce Vulnerability to Climate Extremes

    NASA Astrophysics Data System (ADS)

    Jones, Mari R.; Holland, Greg J.; Done, James M.

    2013-12-01

    How does our built environment make society vulnerable to climate extremes such as flooding? What knowledge is required by engineering designers and risk managers to address the associated risks? How can engineering/scientific approaches be adapted to reduce vulnerability to weather and climate extremes? These were some of the key questions posed during a recent workshop at the National Center for Atmospheric Research (NCAR), which was attended by climate scientists, civil engineering practitioners, and governmental departments. Engineering design encompasses a broad range of applications; to focus discussions, this workshop targeted the specific theme of water resources.

  10. Extreme warm temperatures alter forest phenology and productivity in Europe.

    PubMed

    Crabbe, Richard A; Dash, Jadu; Rodriguez-Galiano, Victor F; Janous, Dalibor; Pavelka, Marian; Marek, Michal V

    2016-09-01

    Recent climate warming has shifted the timing of spring and autumn vegetation phenological events in the temperate and boreal forest ecosystems of Europe. In many areas spring phenological events start earlier and autumn events switch between earlier and later onset. Consequently, the length of growing season in mid and high latitudes of European forest is extended. However, the lagged effects (i.e. the impact of a warm spring or autumn on the subsequent phenological events) on vegetation phenology and productivity are less explored. In this study, we have (1) characterised extreme warm spring and extreme warm autumn events in Europe during 2003-2011, and (2) investigated if direct impact on forest phenology and productivity due to a specific warm event translated to a lagged effect in subsequent phenological events. We found that warmer events in spring occurred extensively in high latitude Europe producing a significant earlier onset of greening (OG) in broadleaf deciduous forest (BLDF) and mixed forest (MF). However, this earlier OG did not show any significant lagged effects on autumnal senescence. Needleleaf evergreen forest (NLEF), BLDF and MF showed a significantly delayed end of senescence (EOS) as a result of extreme warm autumn events; and in the following year's spring phenological events, OG started significantly earlier. Extreme warm spring events directly led to significant (p=0.0189) increases in the productivity of BLDF. In order to have a complete understanding of ecosystems response to warm temperature during key phenological events, particularly autumn events, the lagged effect on the next growing season should be considered. PMID:27152990

  11. Extreme warm temperatures alter forest phenology and productivity in Europe.

    PubMed

    Crabbe, Richard A; Dash, Jadu; Rodriguez-Galiano, Victor F; Janous, Dalibor; Pavelka, Marian; Marek, Michal V

    2016-09-01

    Recent climate warming has shifted the timing of spring and autumn vegetation phenological events in the temperate and boreal forest ecosystems of Europe. In many areas spring phenological events start earlier and autumn events switch between earlier and later onset. Consequently, the length of growing season in mid and high latitudes of European forest is extended. However, the lagged effects (i.e. the impact of a warm spring or autumn on the subsequent phenological events) on vegetation phenology and productivity are less explored. In this study, we have (1) characterised extreme warm spring and extreme warm autumn events in Europe during 2003-2011, and (2) investigated if direct impact on forest phenology and productivity due to a specific warm event translated to a lagged effect in subsequent phenological events. We found that warmer events in spring occurred extensively in high latitude Europe producing a significant earlier onset of greening (OG) in broadleaf deciduous forest (BLDF) and mixed forest (MF). However, this earlier OG did not show any significant lagged effects on autumnal senescence. Needleleaf evergreen forest (NLEF), BLDF and MF showed a significantly delayed end of senescence (EOS) as a result of extreme warm autumn events; and in the following year's spring phenological events, OG started significantly earlier. Extreme warm spring events directly led to significant (p=0.0189) increases in the productivity of BLDF. In order to have a complete understanding of ecosystems response to warm temperature during key phenological events, particularly autumn events, the lagged effect on the next growing season should be considered.

  12. Statistics of extreme events with application to climate

    SciTech Connect

    Abarbanel, H.; Koonin, S.; Levine, H.; MacDonald, G.; Rothaus, O.

    1992-01-10

    The statistical theory of extreme events is applied to observed global average temperature records and to simplified models of climate. Both hands of records exhibit behavior in the tails of the distribution that would be expected from a random variable having a a normal distribution. A simple nonlinear model of climate due to Lorenz is used to demonstrate that the physical dimensions of the underlying attractor, determined by applicable conservation laws, limits the range of extremes. These limits are not reached in either observed series or in more complex models of climate. The effect of a shift in mean on the frequency of extremes is discussed with special reference to possible thresholds for damage to climate variability.

  13. Mekong River flow and hydrological extremes under climate change

    NASA Astrophysics Data System (ADS)

    Phi Hoang, Long; Lauri, Hannu; Kummu, Matti; Koponen, Jorma; van Vliet, Michelle T. H.; Supit, Iwan; Leemans, Rik; Kabat, Pavel; Ludwig, Fulco

    2016-07-01

    Climate change poses critical threats to water-related safety and sustainability in the Mekong River basin. Hydrological impact signals from earlier Coupled Model Intercomparison Project phase 3 (CMIP3)-based assessments, however, are highly uncertain and largely ignore hydrological extremes. This paper provides one of the first hydrological impact assessments using the CMIP5 climate projections. Furthermore, we model and analyse changes in river flow regimes and hydrological extremes (i.e. high-flow and low-flow conditions). In general, the Mekong's hydrological cycle intensifies under future climate change. The scenario's ensemble mean shows increases in both seasonal and annual river discharges (annual change between +5 and +16 %, depending on location). Despite the overall increasing trend, the individual scenarios show differences in the magnitude of discharge changes and, to a lesser extent, contrasting directional changes. The scenario's ensemble, however, shows reduced uncertainties in climate projection and hydrological impacts compared to earlier CMIP3-based assessments. We further found that extremely high-flow events increase in both magnitude and frequency. Extremely low flows, on the other hand, are projected to occur less often under climate change. Higher low flows can help reducing dry season water shortage and controlling salinization in the downstream Mekong Delta. However, higher and more frequent peak discharges will exacerbate flood risks in the basin. Climate-change-induced hydrological changes will have important implications for safety, economic development, and ecosystem dynamics and thus require special attention in climate change adaptation and water management.

  14. Observed and Projected Climate Extremities in Chennai Metropolitan Area

    NASA Astrophysics Data System (ADS)

    Anushiya, j.; Andimuthu, R.

    2013-12-01

    Analyses of observed climate throughout world revealed some significant changes in the extremes. Any change in the frequency or severity of extreme climate events would have profound impacts on the resilience of nature and society. It is thus very important to analyze extreme events to reliably monitor and detect climate change. Chennai is the fourth largest metropolis in India and one of the fastest growing economic and Industrial growth centers in South Asia. Population has grown rapidly in the last 20 years due to its major industrialization and tremendous growth. Already Chennai's day and night time Temperature shows an increasing trend. The past incidence of catastrophic flooding was observed in the city due to heavy rains associated with depressions and cyclonic storm lead floods in major rivers. After 2000, the incidents were reported repeatedly. The effort has made in this study to find the observed climate extremities over the past years and in the future. For observed changes, IMD gridded data set, and station data are used. Future high resolution climate scenarios (0.220x0.220) are developed through RCM using PRECIS. The boundary data have provided by the UK Met office. The selected members are simulated under the A1B scenario (a mid range emission scenario) for a continuous run till 2100. Climate indices listed by Expert Team (ET) on Climate Change Detection and Indices (ETCCDI) by the CLIVAR are considered in this study. The indices were obtained using the software package RClimDex. Kendall's tau based slope estimator has been used to find the significance lavel. The results shows the significant increasing tendency of warm days (TX90P) in the past and in future. The trends in extreme wet days (R99P) are also increased. The growth in population, urban and industrial area, economic activities, depletion of natural resources along with changing climate are forced to develop the infrastructure includes climate friendly policies to adopt and to ensure the

  15. Can quantile mapping improve precipitation extremes from regional climate models?

    NASA Astrophysics Data System (ADS)

    Tani, Satyanarayana; Gobiet, Andreas

    2015-04-01

    The ability of quantile mapping to accurately bias correct regard to precipitation extremes is investigated in this study. We developed new methods by extending standard quantile mapping (QMα) to improve the quality of bias corrected extreme precipitation events as simulated by regional climate model (RCM) output. The new QM version (QMβ) was developed by combining parametric and nonparametric bias correction methods. The new nonparametric method is tested with and without a controlling shape parameter (Qmβ1 and Qmβ0, respectively). Bias corrections are applied on hindcast simulations for a small ensemble of RCMs at six different locations over Europe. We examined the quality of the extremes through split sample and cross validation approaches of these three bias correction methods. This split-sample approach mimics the application to future climate scenarios. A cross validation framework with particular focus on new extremes was developed. Error characteristics, q-q plots and Mean Absolute Error (MAEx) skill scores are used for evaluation. We demonstrate the unstable behaviour of correction function at higher quantiles with QMα, whereas the correction functions with for QMβ0 and QMβ1 are smoother, with QMβ1 providing the most reasonable correction values. The result from q-q plots demonstrates that, all bias correction methods are capable of producing new extremes but QMβ1 reproduces new extremes with low biases in all seasons compared to QMα, QMβ0. Our results clearly demonstrate the inherent limitations of empirical bias correction methods employed for extremes, particularly new extremes, and our findings reveals that the new bias correction method (Qmß1) produces more reliable climate scenarios for new extremes. These findings present a methodology that can better capture future extreme precipitation events, which is necessary to improve regional climate change impact studies.

  16. Climate Change, Extreme Weather Events, and Human Health Implications in the Asia Pacific Region.

    PubMed

    Hashim, Jamal Hisham; Hashim, Zailina

    2016-03-01

    The Asia Pacific region is regarded as the most disaster-prone area of the world. Since 2000, 1.2 billion people have been exposed to hydrometeorological hazards alone through 1215 disaster events. The impacts of climate change on meteorological phenomena and environmental consequences are well documented. However, the impacts on health are more elusive. Nevertheless, climate change is believed to alter weather patterns on the regional scale, giving rise to extreme weather events. The impacts from extreme weather events are definitely more acute and traumatic in nature, leading to deaths and injuries, as well as debilitating and fatal communicable diseases. Extreme weather events include heat waves, cold waves, floods, droughts, hurricanes, tropical cyclones, heavy rain, and snowfalls. Globally, within the 20-year period from 1993 to 2012, more than 530 000 people died as a direct result of almost 15 000 extreme weather events, with losses of more than US$2.5 trillion in purchasing power parity.

  17. Weather Extremes, Climate Change and Adaptive Governance

    NASA Astrophysics Data System (ADS)

    Veland, S.; Lynch, A. H.

    2014-12-01

    Human societies have become a geologic agent of change, and with this is an increasing awareness of the environment risks that confront human activities and values. More frequent and extreme hydroclimate events, anomalous tropical cyclone seasons, heat waves and droughts have all been documented, and many rigorously attributed to fossil fuel emissions (e.g. DeGaetano 2009; Hoyos et al. 2006). These extremes, however, do not register themselves in the abstract - they occur in particular places, affecting particular populations and ecosystems (Turner et al. 2003). This can be considered to present a policy window to decrease vulnerability and enhance emergency management. However, the asymmetrical character of these events may lead some to treat remote areas or disenfranchised populations as capable of absorbing the environmental damage attributable to the collective behavior of those residing in wealthy, populous, industrialized societies (Young 1989). Sound policies for adaptation to changing extremes must take into account the multiple interests and resource constraints for the populations affected and their broader contexts. Minimizing vulnerability to weather extremes is only one of many interests in human societies, and as noted, this interest competes with the others for limited time, attention, funds and other resources. Progress in reducing vulnerability also depends on policy that integrates the best available local and scientific knowledge and experience elsewhere. This improves the chance that each policy will succeed, but there are no guarantees. Each policy must be recognized as a matter of trial and error to some extent; surprises are inevitable. Thus each policy should be designed to fail gracefully if it fails, to learn from the experience, and to leave resources sufficient to implement the lessons learned. Overall policy processes must be quasi-evolutionary, avoiding replication without modification of failed policies and building on the successes

  18. Evaluating wind extremes in CMIP5 climate models

    NASA Astrophysics Data System (ADS)

    Kumar, Devashish; Mishra, Vimal; Ganguly, Auroop R.

    2015-07-01

    Wind extremes have consequences for renewable energy sectors, critical infrastructures, coastal ecosystems, and insurance industry. Considerable debates remain regarding the impacts of climate change on wind extremes. While climate models have occasionally shown increases in regional wind extremes, a decline in the magnitude of mean and extreme near-surface wind speeds has been recently reported over most regions of the Northern Hemisphere using observed data. Previous studies of wind extremes under climate change have focused on selected regions and employed outputs from the regional climate models (RCMs). However, RCMs ultimately rely on the outputs of global circulation models (GCMs), and the value-addition from the former over the latter has been questioned. Regional model runs rarely employ the full suite of GCM ensembles, and hence may not be able to encapsulate the most likely projections or their variability. Here we evaluate the performance of the latest generation of GCMs, the Coupled Model Intercomparison Project phase 5 (CMIP5), in simulating extreme winds. We find that the multimodel ensemble (MME) mean captures the spatial variability of annual maximum wind speeds over most regions except over the mountainous terrains. However, the historical temporal trends in annual maximum wind speeds for the reanalysis data, ERA-Interim, are not well represented in the GCMs. The historical trends in extreme winds from GCMs are statistically not significant over most regions. The MME model simulates the spatial patterns of extreme winds for 25-100 year return periods. The projected extreme winds from GCMs exhibit statistically less significant trends compared to the historical reference period.

  19. Climatic Extremes and Food Grain Production in India

    NASA Astrophysics Data System (ADS)

    A, A.; Mishra, V.

    2015-12-01

    Climate change is likely to affect food and water security in India. India has witnessed tremendous growth in its food production after the green revolution. However, during the recent decades the food grain yields were significantly affected by the extreme climate and weather events. Air temperature and associated extreme events (number of hot days and hot nights, heat waves) increased significantly during the last 50 years in the majority of India. More remarkably, a substantial increase in mean and extreme temperatures was observed during the winter season in India. On the other hand, India witnessed extreme flood and drought events that have become frequent during the past few decades. Extreme rainfall during the non-monsoon season adversely affected the food grain yields and results in tremendous losses in several parts of the country. Here we evaluate the changes in hydroclimatic extremes and its linkage with the food grain production in India. We use observed food grain yield data for the period of 1980-2012 at district level. We understand the linkages between food grain yield and crop phenology obtained from the high resolution leaf area index and NDVI datasets from satellites. We used long-term observed data of daily precipitation and maximum and minimum temperatures to evaluate changes in the extreme events. We use statistical models to develop relationships between crop yields, mean and extreme temperatures for various crops to understand the sensitivity of these crops towards changing climatic conditions. We find that some of the major crop types and predominant crop growing areas have shown a significant sensitivity towards changes in extreme climatic conditions in India.

  20. Contrasting responses of mean and extreme snowfall to climate change.

    PubMed

    O'Gorman, Paul A

    2014-08-28

    Snowfall is an important element of the climate system, and one that is expected to change in a warming climate. Both mean snowfall and the intensity distribution of snowfall are important, with heavy snowfall events having particularly large economic and human impacts. Simulations with climate models indicate that annual mean snowfall declines with warming in most regions but increases in regions with very low surface temperatures. The response of heavy snowfall events to a changing climate, however, is unclear. Here I show that in simulations with climate models under a scenario of high emissions of greenhouse gases, by the late twenty-first century there are smaller fractional changes in the intensities of daily snowfall extremes than in mean snowfall over many Northern Hemisphere land regions. For example, for monthly climatological temperatures just below freezing and surface elevations below 1,000 metres, the 99.99th percentile of daily snowfall decreases by 8% in the multimodel median, compared to a 65% reduction in mean snowfall. Both mean and extreme snowfall must decrease for a sufficiently large warming, but the climatological temperature above which snowfall extremes decrease with warming in the simulations is as high as -9 °C, compared to -14 °C for mean snowfall. These results are supported by a physically based theory that is consistent with the observed rain-snow transition. According to the theory, snowfall extremes occur near an optimal temperature that is insensitive to climate warming, and this results in smaller fractional changes for higher percentiles of daily snowfall. The simulated changes in snowfall that I find would influence surface snow and its hazards; these changes also suggest that it may be difficult to detect a regional climate-change signal in snowfall extremes.

  1. TECA: A Parallel Toolkit for Extreme Climate Analysis

    SciTech Connect

    Prabhat, Mr; Ruebel, Oliver; Byna, Surendra; Wu, Kesheng; Li, Fuyu; Wehner, Michael; Bethel, E. Wes

    2012-03-12

    We present TECA, a parallel toolkit for detecting extreme events in large climate datasets. Modern climate datasets expose parallelism across a number of dimensions: spatial locations, timesteps and ensemble members. We design TECA to exploit these modes of parallelism and demonstrate a prototype implementation for detecting and tracking three classes of extreme events: tropical cyclones, extra-tropical cyclones and atmospheric rivers. We process a modern TB-sized CAM5 simulation dataset with TECA, and demonstrate good runtime performance for the three case studies.

  2. Impacts of climate extremes on activity sectors stakeholders' perspective

    NASA Astrophysics Data System (ADS)

    Kundzewicz, Z. W.; Giannakopoulos, C.; Schwarb, M.; Stjernquist, I.; Schlyter, P.; Szwed, M.; Palutikof, J.

    2008-06-01

    Significant changes in the climatic system have been observed, which may be attributed to human-enhanced greenhouse effect. Even stronger changes are projected for the future, impacting in an increasing way on human activity sectors. The present contribution, prepared in the framework of the MICE (Modelling the Impact of Climate Extremes) Project of the European Union, reviews how climate change may impact on winter tourism in the Alpine region, intense precipitation and flood potential in central Europe, forest damage in Scandinavia and beach holidays in the Mediterranean coast. Impacts are likely to be serious and largely adverse. Due to a lack of adequate information and lack of broadly accepted and reliable mathematical models describing the impact of changes in climate extremes on these activity sectors, it has been found useful to use expert judgement based impact assessment. Accordingly, regional mini-workshops were organized serving as platforms for communication between scientists and stakeholders, vehicles for dissemination of the state-of-the-art of the scientific understanding and for learning stakeholders’ view on extreme events, their impacts and the preparedness system. Stakeholders had the opportunity to react to the scientific results and to reflect on their perception of the likely impacts of projected changes in extremes on relevant activity sectors and the potential to adapt and avert adverse consequences. The results reported in this paper present the stakeholders’ suggestions for essential information on different extreme event impacts and their needs from science.

  3. Biodiversity increases the resistance of ecosystem productivity to climate extremes.

    PubMed

    Isbell, Forest; Craven, Dylan; Connolly, John; Loreau, Michel; Schmid, Bernhard; Beierkuhnlein, Carl; Bezemer, T Martijn; Bonin, Catherine; Bruelheide, Helge; de Luca, Enrica; Ebeling, Anne; Griffin, John N; Guo, Qinfeng; Hautier, Yann; Hector, Andy; Jentsch, Anke; Kreyling, Jürgen; Lanta, Vojtěch; Manning, Pete; Meyer, Sebastian T; Mori, Akira S; Naeem, Shahid; Niklaus, Pascal A; Polley, H Wayne; Reich, Peter B; Roscher, Christiane; Seabloom, Eric W; Smith, Melinda D; Thakur, Madhav P; Tilman, David; Tracy, Benjamin F; van der Putten, Wim H; van Ruijven, Jasper; Weigelt, Alexandra; Weisser, Wolfgang W; Wilsey, Brian; Eisenhauer, Nico

    2015-10-22

    It remains unclear whether biodiversity buffers ecosystems against climate extremes, which are becoming increasingly frequent worldwide. Early results suggested that the ecosystem productivity of diverse grassland plant communities was more resistant, changing less during drought, and more resilient, recovering more quickly after drought, than that of depauperate communities. However, subsequent experimental tests produced mixed results. Here we use data from 46 experiments that manipulated grassland plant diversity to test whether biodiversity provides resistance during and resilience after climate events. We show that biodiversity increased ecosystem resistance for a broad range of climate events, including wet or dry, moderate or extreme, and brief or prolonged events. Across all studies and climate events, the productivity of low-diversity communities with one or two species changed by approximately 50% during climate events, whereas that of high-diversity communities with 16-32 species was more resistant, changing by only approximately 25%. By a year after each climate event, ecosystem productivity had often fully recovered, or overshot, normal levels of productivity in both high- and low-diversity communities, leading to no detectable dependence of ecosystem resilience on biodiversity. Our results suggest that biodiversity mainly stabilizes ecosystem productivity, and productivity-dependent ecosystem services, by increasing resistance to climate events. Anthropogenic environmental changes that drive biodiversity loss thus seem likely to decrease ecosystem stability, and restoration of biodiversity to increase it, mainly by changing the resistance of ecosystem productivity to climate events.

  4. Biodiversity increases the resistance of ecosystem productivity to climate extremes.

    PubMed

    Isbell, Forest; Craven, Dylan; Connolly, John; Loreau, Michel; Schmid, Bernhard; Beierkuhnlein, Carl; Bezemer, T Martijn; Bonin, Catherine; Bruelheide, Helge; de Luca, Enrica; Ebeling, Anne; Griffin, John N; Guo, Qinfeng; Hautier, Yann; Hector, Andy; Jentsch, Anke; Kreyling, Jürgen; Lanta, Vojtěch; Manning, Pete; Meyer, Sebastian T; Mori, Akira S; Naeem, Shahid; Niklaus, Pascal A; Polley, H Wayne; Reich, Peter B; Roscher, Christiane; Seabloom, Eric W; Smith, Melinda D; Thakur, Madhav P; Tilman, David; Tracy, Benjamin F; van der Putten, Wim H; van Ruijven, Jasper; Weigelt, Alexandra; Weisser, Wolfgang W; Wilsey, Brian; Eisenhauer, Nico

    2015-10-22

    It remains unclear whether biodiversity buffers ecosystems against climate extremes, which are becoming increasingly frequent worldwide. Early results suggested that the ecosystem productivity of diverse grassland plant communities was more resistant, changing less during drought, and more resilient, recovering more quickly after drought, than that of depauperate communities. However, subsequent experimental tests produced mixed results. Here we use data from 46 experiments that manipulated grassland plant diversity to test whether biodiversity provides resistance during and resilience after climate events. We show that biodiversity increased ecosystem resistance for a broad range of climate events, including wet or dry, moderate or extreme, and brief or prolonged events. Across all studies and climate events, the productivity of low-diversity communities with one or two species changed by approximately 50% during climate events, whereas that of high-diversity communities with 16-32 species was more resistant, changing by only approximately 25%. By a year after each climate event, ecosystem productivity had often fully recovered, or overshot, normal levels of productivity in both high- and low-diversity communities, leading to no detectable dependence of ecosystem resilience on biodiversity. Our results suggest that biodiversity mainly stabilizes ecosystem productivity, and productivity-dependent ecosystem services, by increasing resistance to climate events. Anthropogenic environmental changes that drive biodiversity loss thus seem likely to decrease ecosystem stability, and restoration of biodiversity to increase it, mainly by changing the resistance of ecosystem productivity to climate events. PMID:26466564

  5. Future climate projections of extreme precipitation and temperature distributions by using an Extreme Value Theory non-stationary model

    NASA Astrophysics Data System (ADS)

    Casati, B.; Lefaivre, L.

    2009-04-01

    Extreme weather events can cause large damages and losses, and have high societal and economical impacts. Climate model integrations predict increases in both frequency and intensity of extreme events under enhanced greenhouse conditions. Better understanding of the capabilities of climate models in representing the present climate extremes, joint with the analysis of the future climate projections for extreme events, can help to forewarn society from future high-impact events, and possibly better develop adaptation strategies. Extreme Value Theory (EVT) provides a well established and robust framework to analyse the behaviour of extreme weather events for the present climate and future projections. In this study a non-stationary model for Generalised Extreme Value (GEV) distributions is used to analyse the trend of the distributions of extreme precipitation and temperatures, in the context of a changing climate. The analysis is performed for the climate projections of the Canadian Regional Climate Model (CRCM), under a SRES A2 emission scenario, for annual, seasonal and monthly extremes, for 12 regions characterised by different climatologies over the North American domain. Significant positive trends for the location of the distributions are found in most regions, indicating an expected increase in extreme value intensities, whereas the scale (variability) and shape (tail values) of the extreme distributions seem not to vary significantly. Extreme events, such as intense convective precipitation, are often associated to small-scale features. The enhanced resolution of Regional Climate Models enables to better represent such extreme events, with respect to Global Climate Models. However the resolution of these models is sometimes still too coarse to reproduce realistic extremes. To address this representativeness issue, statistical downscaling of the CRCM projections is performed. The downscaling relation is obtained by comparing the GEV distributions for the CRCM

  6. Impacts of Climate Change on the Climate Extremes of the Middle East

    NASA Astrophysics Data System (ADS)

    Turp, M. Tufan; Collu, Kamil; Deler, F. Busra; Ozturk, Tugba; Kurnaz, M. Levent

    2016-04-01

    The Middle East is one of the most vulnerable regions to the impacts of climate change. Because of the importance of the region and its vulnerability to global climate change, the studies including the investigation of projected changes in the climate of the Middle East play a crucial role in order to struggle with the negative effects of climate change. This research points out the relationship between the climate change and climate extremes indices in the Middle East and it investigates the changes in the number of extreme events as described by the joint CCl/CLIVAR/JCOMM Expert Team (ET) on Climate Change Detection and Indices (ETCCDI). As part of the study, the regional climate model (RegCM4.4) of the Abdus Salam International Centre for Theoretical Physics (ICTP) is run to obtain future projection data. This research has been supported by Boǧaziçi University Research Fund Grant Number 10421.

  7. A Weather climate change Impact Study at Extreme Resolution (WISER)

    NASA Astrophysics Data System (ADS)

    Gadian, A.; Burton, R.; Bruyere, C. L.; Done, J.; Tye, M. R.; Holland, G. J.; Thielen, J.; Blyth, A. M.

    2014-12-01

    Understanding and simulation of weather scale processes is required to understand extremes in the rapidly changing climate. The resolution required to include meso-scale features, is still out of the reach of climate model resolution, and this project attempts to include the important meso-scale features. WISER (Weather climate change Impact Study at Extreme Resolution) is a regional climate study to use a numerical weather model (WRF), in a channel formulation (+/- 68 degrees latitude) at a resolution of 20 km at the equator reducing to 9 km at the Northern and Southern boundaries. The inner domain nested regional model at a resolution of 3-4 km over Western Europe aims at resolving the larger convective scale precipitation events statistically. (see figure for geometrical domain set up). The outer domain is driven by ERA interim climate reanalysis global fields for recent decades 1989-2001; the nested inner domain d02 is driven by the outer domain. The inner model climatological statistics are compared with observations and with those from the outer domain, with particular reference for the statistical convective precipitation extremes. The extremes of the pdfs are shown to be better represented by the increase in resolution and suggest that this could be a tool useful in examining the likely extremes in future climates. The data also provides an assessment of the uncertainty in the precipitation extremes and an alternative approach to ownscaling. The overall aim is to examine statistical changes in(a) general precipitation over western Europe and the UK,(b) in quantity and frequency of severe and hazardous convective rainfall events. The future work-plan is(i) to complete simulations for the decade 1989-2000 driven by ERA-Interim reanalysis data(ii) to complete simulations for the same decade with boundary CESM/CAM climate model data to compute offset and bias corrections(iii) to complete climate scenarios for decadal periods, 2020-2030 initially and later 2050

  8. Changes in the variability of extreme climate events in Latvia

    NASA Astrophysics Data System (ADS)

    Avotniece, Zanita; Lizuma, Lita; Briede, Agrita; Klavins, Maris

    2015-04-01

    Recent changes in the mean values of surface air temperature and precipitation have led to significant local changes in hazardous and extreme events in many parts of the world, including the Northern Europe and Latvia. The observed trends in the changes of such extreme climate events indicate that extremes associated with high temperatures and precipitation are becoming more frequent in Latvia, however not much is known about the changes in variability of these extreme events. This study investigated the long-term trends and variability of extreme temperature and precipitation events as defined by the ECA&D in 10 meteorological observation stations in Latvia over the period 1925-2012. In order to detect and study the changes in variability and anomalies of extreme events, a comparison of three different time scales was performed: 1931-1960, 1961-1990,1981-2010. The results of the analysis revealed steady changes in some extremes while others have experienced a significant change in variability in the most recent 30-year period. Due to the specifics in the spatial distribution of extreme events, the results show differences in the behaviour of extreme events over the country.

  9. Climate change and hydrological extremes in Belgian catchments

    NASA Astrophysics Data System (ADS)

    Baguis, P.; Roulin, E.; Willems, P.; Ntegeka, V.

    2010-07-01

    In this study we focus our attention on the climate change impacts on the hydrological balance in Belgium. There are two main rivers in the country, the Scheldt and the Meuse, supplied with water almost exclusively by precipitation. With the climate change projected by climate models for the end of the current century, one would expect that the hydrological regime of the rivers may be affected mainly through the changes in precipitation patterns and the increased potential evapotranspiration (PET) due to increased temperature throughout the year. We examine the hydrology of two important tributaries of the rivers Scheldt and Meuse, the Gete and the Ourthe, respectively. Our analysis is based on simulations with the SCHEME hydrological model and on climate change data from the European PRUDENCE project. Two emission scenarios are considered, the SRES A2 and B2 scenarios, and the perturbation (or delta) method is used in order to assess the climate change signal at monthly time scale and provide appropriate input time series for the hydrological simulations. The ensemble of climate change scenarios used allows us to estimate the combined model and scenario uncertainty in the streamflow calculations, inherent to this kind of analysis. In this context, we also analyze extreme river flows using two probability distribution families, allowing us to quantify the shift of the extremes under climate change conditions.

  10. Improving Predictions and Management of Hydrological Extremes through Climate Services

    NASA Astrophysics Data System (ADS)

    van den Hurk, Bart; Wijngaard, Janet; Pappenberger, Florian; Bouwer, Laurens; Weerts, Albrecht; Buontempo, Carlo; Doescher, Ralf; Manez, Maria; Ramos, Maria-Helena; Hananel, Cedric; Ercin, Ertug; Hunink, Johannes; Klein, Bastian; Pouget, Laurent; Ward, Philip

    2016-04-01

    The EU Roadmap on Climate Services can be seen as a result of convergence between the society's call for "actionable research", and the climate research community providing tailored data, information and knowledge. However, although weather and climate have clearly distinct definitions, a strong link between weather and climate services exists that is not explored extensively. Stakeholders being interviewed in the context of the Roadmap consider climate as a far distant long term feature that is difficult to consider in present-day decision taking, which is dominated by daily experience with handling extreme events. It is argued that this experience is a rich source of inspiration to increase society's resilience to an unknown future. A newly started European research project, IMPREX, is built on the notion that "experience in managing current day weather extremes is the best learning school to anticipate consequences of future climate". This paper illustrates possible ways to increase the link between information and services addressing weather and climate time scales by discussing the underlying concepts of IMPREX and its expected outcome.

  11. Increasing impacts of climate extremes on critical infrastructures in Europe

    NASA Astrophysics Data System (ADS)

    Forzieri, Giovanni; Bianchi, Alessandra; Feyen, Luc; Silva, Filipe Batista e.; Marin, Mario; Lavalle, Carlo; Leblois, Antoine

    2016-04-01

    The projected increases in exposure to multiple climate hazards in many regions of Europe, emphasize the relevance of a multi-hazard risk assessment to comprehensively quantify potential impacts of climate change and develop suitable adaptation strategies. In this context, quantifying the future impacts of climatic extremes on critical infrastructures is crucial due to their key role for human wellbeing and their effects on the overall economy. Critical infrastructures describe the existing assets and systems that are essential for the maintenance of vital societal functions, health, safety, security, economic or social well-being of people, and the disruption or destruction of which would have a significant impact as a result of the failure to maintain those functions. We assess the direct damages of heat and cold waves, river and coastal flooding, droughts, wildfires and windstorms to energy, transport, industry and social infrastructures in Europe along the 21st century. The methodology integrates in a coherent framework climate hazard, exposure and vulnerability components. Overall damage is expected to rise up to 38 billion €/yr, ten time-folds the current climate damage, with drastic variations in risk scenarios. Exemplificative are drought and heat-related damages that could represent 70% of the overall climate damage in 2080s versus the current 12%. Many regions, prominently Southern Europe, will likely suffer multiple stresses and systematic infrastructure failures due to climate extremes if no suitable adaptation measures will be taken.

  12. Identifying causal effects of climate extremes on societies

    NASA Astrophysics Data System (ADS)

    Hsiang, S. M.

    2015-12-01

    We discuss recent advances in the application of quasi-experimental techniques to identify causal effects of climate extremes on human societies using historical data. Results identifying effects on economic productivity, violence, migration, and global trade will be discussed. We will discuss how these statistical findings can be applied to calibrate modeling exercises and areas for future research.

  13. Climate Change and Extreme Weather Impacts on Salt Marsh Plants

    EPA Science Inventory

    Regional assessments of climate change impacts on New England demonstrate a clear rise in rainfall over the past century. The number of extreme precipitation events (i.e., two or more inches of rain falling during a 48-hour period) has also increased over the past few decades. ...

  14. Assessing Extremes Climatology Using NWS Local Climate Analysis Tool

    NASA Astrophysics Data System (ADS)

    Timofeyeva, M. M.; Hollingshead, A.; Hilderbrand, D.; Mayes, B.; Hartley, T.; Kempf McGavock, N. M.; Lau, E.; Olenic, E. A.; Motta, B.; Bunge, R.; Brown, L. E.; Fritsch, F.

    2010-12-01

    tornadoes, flash floods, storminess, extreme weather events, etc. LCAT will expand the suite of NWS climate products. The LCAT development utilizes NWS Operations and Services Improvement Process (OSIP) to document the field and user requirements, develop solutions, and prioritize resources. OSIP is a five work-stage process separated by four gate reviews. LCAT is currently at work-stage three: Research Demonstration and Solution Analysis. Gate 1 and 2 reviews identified LCAT as a high strategic priority project with a very high operational need. The Integrated Working Team, consisting of NWS field representatives, assists in tool function design and identification of LCAT operational deployment support.

  15. Assessment of a climate model to reproduce rainfall variability and extremes over Southern Africa

    NASA Astrophysics Data System (ADS)

    Williams, C. J. R.; Kniveton, D. R.; Layberry, R.

    2010-01-01

    It is increasingly accepted that any possible climate change will not only have an influence on mean climate but may also significantly alter climatic variability. A change in the distribution and magnitude of extreme rainfall events (associated with changing variability), such as droughts or flooding, may have a far greater impact on human and natural systems than a changing mean. This issue is of particular importance for environmentally vulnerable regions such as southern Africa. The sub-continent is considered especially vulnerable to and ill-equipped (in terms of adaptation) for extreme events, due to a number of factors including extensive poverty, famine, disease and political instability. Rainfall variability and the identification of rainfall extremes is a function of scale, so high spatial and temporal resolution data are preferred to identify extreme events and accurately predict future variability. The majority of previous climate model verification studies have compared model output with observational data at monthly timescales. In this research, the assessment of ability of a state of the art climate model to simulate climate at daily timescales is carried out using satellite-derived rainfall data from the Microwave Infrared Rainfall Algorithm (MIRA). This dataset covers the period from 1993 to 2002 and the whole of southern Africa at a spatial resolution of 0.1° longitude/latitude. This paper concentrates primarily on the ability of the model to simulate the spatial and temporal patterns of present-day rainfall variability over southern Africa and is not intended to discuss possible future changes in climate as these have been documented elsewhere. Simulations of current climate from the UK Meteorological Office Hadley Centre's climate model, in both regional and global mode, are firstly compared to the MIRA dataset at daily timescales. Secondly, the ability of the model to reproduce daily rainfall extremes is assessed, again by a comparison with

  16. Projections of African drought extremes in CORDEX regional climate simulations

    NASA Astrophysics Data System (ADS)

    Gbobaniyi, Emiola; Nikulin, Grigory; Jones, Colin; Kjellström, Erik

    2013-04-01

    We investigate trends in drought extremes for different climate regions of the African continent over a combined historical and future period 1951-2100. Eight CMIP5 coupled atmospheric global climate models (CanESM2, CNRM-CM5, HadGEM2-ES, NorESM1-M, EC-EARTH, MIROC5, GFDL-ESM2M and MPI-ESM-LR) under two forcing scenarios, the relative concentration pathways (RCP) 4.5 and 8.5, with spatial resolution varying from about 1° to 3° are downscaled to 0.44° resolution by the Rossby Centre (SMHI) regional climate model RCA4. We use data from the ensuing ensembles of CORDEX-Africa regional climate simulations to explore three drought indices namely: standardized precipitation index (SPI), moisture index (MI) and difference in precipitation and evaporation (P-E). Meteorological and agricultural drought conditions are assessed in our analyses and a climate change signal is obtained for the SPI by calculating gamma functions for future SPI with respect to a baseline present climate. Results for the RCP4.5 and RCP8.5 scenarios are inter-compared to assess uncertainties in the future projections. We show that there is a pronounced sensitivity to the choice of forcing GCM which indicates that assessments of future drought conditions in Africa would benefit from large model ensembles. We also note that the results are sensitive to the choice of drought index. We discuss both spatial and temporal variability of drought extremes for different climate zones of Africa and the importance of the ensemble mean. Our study highlights the usefulness of CORDEX simulations in identifying possible future impacts of climate at local and regional scales.

  17. Altered dynamics of forest recovery under a changing climate.

    PubMed

    Anderson-Teixeira, Kristina J; Miller, Adam D; Mohan, Jacqueline E; Hudiburg, Tara W; Duval, Benjamin D; Delucia, Evan H

    2013-07-01

    Forest regeneration following disturbance is a key ecological process, influencing forest structure and function, species assemblages, and ecosystem-climate interactions. Climate change may alter forest recovery dynamics or even prevent recovery, triggering feedbacks to the climate system, altering regional biodiversity, and affecting the ecosystem services provided by forests. Multiple lines of evidence - including global-scale patterns in forest recovery dynamics; forest responses to experimental manipulation of CO2 , temperature, and precipitation; forest responses to the climate change that has already occurred; ecological theory; and ecosystem and earth system models - all indicate that the dynamics of forest recovery are sensitive to climate. However, synthetic understanding of how atmospheric CO2 and climate shape trajectories of forest recovery is lacking. Here, we review these separate lines of evidence, which together demonstrate that the dynamics of forest recovery are being impacted by increasing atmospheric CO2 and changing climate. Rates of forest recovery generally increase with CO2 , temperature, and water availability. Drought reduces growth and live biomass in forests of all ages, having a particularly strong effect on seedling recruitment and survival. Responses of individual trees and whole-forest ecosystems to CO2 and climate manipulations often vary by age, implying that forests of different ages will respond differently to climate change. Furthermore, species within a community typically exhibit differential responses to CO2 and climate, and altered community dynamics can have important consequences for ecosystem function. Age- and species-dependent responses provide a mechanism by which climate change may push some forests past critical thresholds such that they fail to recover to their previous state following disturbance. Altered dynamics of forest recovery will result in positive and negative feedbacks to climate change. Future research

  18. Climate, extreme heat, and electricity demand in California

    SciTech Connect

    Miller, N.L.; Hayhoe, K.; Jin, J.; Auffhammer, M.

    2008-04-01

    Climate projections from three atmosphere-ocean climate models with a range of low to mid-high temperature sensitivity forced by the Intergovernmental Panel for Climate Change SRES higher, middle, and lower emission scenarios indicate that, over the 21st century, extreme heat events for major cities in heavily air-conditioned California will increase rapidly. These increases in temperature extremes are projected to exceed the rate of increase in mean temperature, along with increased variance. Extreme heat is defined here as the 90 percent exceedance probability (T90) of the local warmest summer days under the current climate. The number of extreme heat days in Los Angeles, where T90 is currently 95 F (32 C), may increase from 12 days to as many as 96 days per year by 2100, implying current-day heat wave conditions may last for the entire summer, with earlier onset. Overall, projected increases in extreme heat under the higher A1fi emission scenario by 2070-2099 tend to be 20-30 percent higher than those projected under the lower B1 emission scenario, ranging from approximately double the historical number of days for inland California cities (e.g. Sacramento and Fresno), up to four times for previously temperate coastal cities (e.g. Los Angeles, San Diego). These findings, combined with observed relationships between high temperature and electricity demand for air-conditioned regions, suggest potential shortfalls in transmission and supply during T90 peak electricity demand periods. When the projected extreme heat and peak demand for electricity are mapped onto current availability, maintaining technology and population constant only for demand side calculations, we find the potential for electricity deficits as high as 17 percent. Similar increases in extreme heat days are suggested for other locations across the U.S. southwest, as well as for developing nations with rapidly increasing electricity demands. Electricity response to recent extreme heat events, such

  19. Case studies of extreme climatic events in the Amazon basin

    NASA Technical Reports Server (NTRS)

    Marengo, Jose A.; Hastenrath, Stefan

    1993-01-01

    The present exploration of climate-anomaly mechanisms, on the basis of surface-climatological and hydrological series, as well as upper-air and satellite observations, gives attention to the March-April rainy season peak in northern Amazonia. While the moderately wet year 1986 exhibited a far-southerly location of the Atlantic near-equatorial trough, and an embedded intertropical convergence zone (ITCZ), the extremely dry El Nino year 1983 featured a more northerly ITCZ. Major mechanisms of extreme rainfall events are synthesized on the basis of these analyses.

  20. Extreme events due to human-induced climate change.

    PubMed

    Mitchell, John F B; Lowe, Jason; Wood, Richard A; Vellinga, Michael

    2006-08-15

    A recent assessment by the intergovernmental panel on climate change concluded that the Earth's climate would be 2-6 degrees C warmer than in the pre-industrial era by the end of the twenty-first century, due to human-induced increases in greenhouse gases. In the absence of other changes, this would lead to the warmest period on Earth for at least the last 1000 years, and probably the last 100,000 years. The large-scale warming is expected to be accompanied by increased frequency and/or intensity of extreme events, such as heatwaves, heavy rainfall, storms and coastal flooding. There are also several possibilities that this large change could initiate nonlinear climate responses which lead to even more extreme and rapid (on the time-scale of decades) climate change, including the collapse of the ocean 'conveyor belt' circulation, the collapse of major ice sheets or the release of large amounts of methane in high latitudes leading to further global warming. Although these catastrophic events are much more speculative than the direct warming due to increased greenhouse gases, their potential impacts are great and therefore should be included in any risk assessment of the impacts of anthropogenic climate change.

  1. Understanding the role of compound events in climate extremes

    NASA Astrophysics Data System (ADS)

    Leonard, Michael; Westra, Seth; Phatak, Aloke; Lambert, Martin; van den Hurk, Bart; McInness, Kathleen; Risby, James; Schuster, Sandra; Jakob, Doerte; Stafford-Smith, Mark

    2013-04-01

    Climate variables give rise to hazards such as cyclones, floods and fires where an extreme impact is the result of a combination of variables rather than any one variable being in an extreme state in isolation. The combination of variables is termed a compound event and the nature of any given compound event will depend upon the variety of physical variables, the range of spatial and temporal scales over which they are linked, the strength of dependence between processes, and the interest of the stakeholder in defining the impact. Modelling compound events is a large, complex and inter-disciplinary undertaking and to facilitate this task influence diagrams are proposed for better defining, mapping, analysing, modelling and communicating the behaviour of the compound event. Ultimately, the greater appreciation of compound events will lead to greater insight and a changed perspective on how impact risks are associated with climate related hazards.

  2. Extreme events evaluation over African cities with regional climate simulations

    NASA Astrophysics Data System (ADS)

    Bucchignani, Edoardo; Mercogliano, Paola; Simonis, Ingo; Engelbrecht, Francois

    2013-04-01

    The warming of the climate system in recent decades is evident from observations and is mainly related to the increase of anthropogenic greenhouse gas concentrations (IPCC, 2012). Given the expected climate change conditions on the African continent, as underlined in different publications, and their associated socio-economic impacts, an evaluation of the specific effects on some strategic African cities on the medium and long-term is of crucial importance with regard to the development of adaptation strategies. Assessments usually focus on averages climate properties rather than on variability or extremes, but often these last ones have more impacts on the society than averages values. Global Coupled Models (GCM) are generally used to simulate future climate scenarios as they guarantee physical consistency between variables; however, due to the coarse spatial resolution, their output cannot be used for impact studies on local scales, which makes necessary the generation of higher resolution climate change data. Regional Climate Models (RCM) describe better the phenomena forced by orography or by coastal lines, or that are related to convection. Therefore they can provide more detailed information on climate extremes that are hard to study and even harder to predict because they are, by definition, rare and obey different statistical laws. The normal bias of the RCM to represent the local climatology is reduced using adequate statistical techniques based on the comparison of the simulated results with long observational time series. In the framework of the EU-FP7 CLUVA (Climate Change and Urban Vulnerability in Africa) project, regional projections of climate change at high resolution (about 8 km), have been performed for selected areas surrounding five African cities. At CMCC, the regional climate model COSMO-CLM has been employed: it is a non-hydrostatic model. For each domain, two simulations have been performed, considering the RCP4.5 and RCP8.5 emission

  3. Scenarios of daily extreme precipitation under climate change

    NASA Astrophysics Data System (ADS)

    Michael, Hofstätter; Christoph, Matulla; Jiafeng, Wang

    2010-05-01

    Daily extreme precipitation events under climate change conditions are the focus of research in our study. Such events can have considerable impacts on wealth and society by causing floodings or mudslides for example. In our study we used daily records of precipitation at 50 stations over Austria covering the period 1963-2006. To calculate the adequate timeseries for the future considering IPCC's climate change scenarios A1B and B1, we applied the analog method. Daily fields of Sea Level Pressure from the NCAR/NCEP1 Reanalysis within the region of Europe (20W-35E/30S-65N), served as the prime predictor between local scale observations and climate simulations out of the MPI-ECHAM5 model. Several return values were determined by fitting a GEV distribution to the timeseries consisting of the three most extreme, declustered events per year. The results reveal that future changes of 20y-return values are within +/-20% for most stations, whereby the signal of change is stronger for the first period (2007-2050) as compared to the later one (2051-2094). This is valid for both IPCC scenarios. We conclude, that even in the relatively small area of Austria both the sign and rate of change in future extreme precipitation, offers a clear diversity among climatological regions. This implies an important aspect for forthcoming studies.

  4. Climate extremes in Malaysia and the equatorial South China Sea

    NASA Astrophysics Data System (ADS)

    Salahuddin, Ahmed; Curtis, Scott

    2011-08-01

    The southern extent of the South China Sea (SCS) is an important natural resource epicenter for Malaysia which experiences climate extremes. This paper documents the variability of extremes in the equatorial SCS through selected ground-based observations of precipitation in Malaysia and ship-based observations of wind data in the Maritime Continent region, to elucidate the interrelationship between precipitation variability over Malaysia and wind variability over the ocean. The data have been carefully inspected and analyzed, and related to the real-time multivariate Madden-Julian Oscillation (MJO) time series. The analysis suggests that the northeast or boreal winter monsoon dominates extreme rainfall in eastern Malaysian cities. Further, the west coast of Peninsular Malaysia and Borneo Malaysia are affected by the MJO differently than the east coast of Peninsular Malaysia. From the wind analysis we found that average zonal wind is westerly from May to September and easterly from November to April. When the active (convective) phase of the MJO is centered over the Maritime Continent, the strong westerly wind bursts are more frequent in the South China Sea. While more investigation is needed, these results suggest that the status of the Madden-Julian Oscillation can be used to help forecast climate extremes in areas of Malaysia.

  5. Financial market response to extreme events indicating climatic change

    NASA Astrophysics Data System (ADS)

    Anttila-Hughes, J. K.

    2016-05-01

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

  6. Climate extremes and the carbon cycle - a review using an integrated approach with regional examples for forests & native ecosystems -

    NASA Astrophysics Data System (ADS)

    Frank, D.; Reichstein, M.; Bahn, M.; Beer, C.; Ciais, P.; Mahecha, M.; Seneviratne, S. I.; Smith, P.; van Oijen, M.; Walz, A.

    2012-04-01

    The terrestrial carbon cycle provides an important biogeochemical feedback to climate and is itself particularly susceptible to extreme climate events. Climate extremes can override any (positive) effects of mean climate change as shown in European and recent US-American heat waves and dry spells. They can impact the structure, composition, and functioning of terrestrial ecosystems and have the potential to cause rapid carbon losses from accumulated stocks. We review how climate extremes like severe droughts, heat waves, extreme precipitation or storms can cause direct impacts on the CO2 fluxes [e.g. due to extreme temperature and/ or drought events] as well as lagged impacts on the carbon cycle [e.g. via an increased fire risk, or disease outbreaks and pest invasions]. The relative impact of the different climate extremes varies according to climate region and vegetation type. We present lagged effects on plant growth (and mortality) in the year(s) following an extreme event and their impacts on the carbon sequestration of forests and natural ecosystems. Comprehensive regional or even continental quantification with regard to extreme events is missing, and especially compound extreme events, the role of lagged effects and aspects of the return frequency are not studied enough. In a case study of a Mediterranean ecosystem we illustrate that the response of the net carbon balance at ecosystem level to regional climate change is hard to predict as interacting and partly compensating processes are affected and several processes which have the ability to substantially alter the carbon balance are not or not sufficiently represented in state-of-the-art biogeochemical models.

  7. Quantifying uncertainties in projections of climate extremes — a perturbed land surface parameter experiment

    NASA Astrophysics Data System (ADS)

    Fischer, Erich; Lawrence, David; Sanderson, Ben

    2010-05-01

    Changes in frequency, intensity and duration of climate extremes have socio-economic impacts that reach far beyond the effects of rising global mean temperatures. We explore changes in climate extremes in response to a doubling of CO2 and corresponding uncertainties using a perturbed physics ensemble. Based on NCAR CCSM 3.5 with a mixed-layer ocean, a 108 member ensemble experiment is performed by perturbing five poorly constrained land surface model parameters individually and in all possible combinations. While the ensemble range of climate sensitivity is found to be substantially smaller than in corresponding atmospheric ensembles, temperature variability changes are highly sensitive to land surface parameter changes. These variability changes have strong implications for the tails of the temperature distribution, the extreme events. Consequently uncertainties of cold and heat extremes induced by poorly constrained land surface parameters are very large. Furthermore, simple land surface parameter perturbations regionally alter the sign of the precipitation response to increased greenhouse gas concentrations. Projections of droughts and heavy rainfall events are highly sensitive to land surface parameters.

  8. Antarctic climate change: extreme events disrupt plastic phenotypic response in Adélie penguins.

    PubMed

    Lescroël, Amélie; Ballard, Grant; Grémillet, David; Authier, Matthieu; Ainley, David G

    2014-01-01

    In the context of predicted alteration of sea ice cover and increased frequency of extreme events, it is especially timely to investigate plasticity within Antarctic species responding to a key environmental aspect of their ecology: sea ice variability. Using 13 years of longitudinal data, we investigated the effect of sea ice concentration (SIC) on the foraging efficiency of Adélie penguins (Pygoscelis adeliae) breeding in the Ross Sea. A 'natural experiment' brought by the exceptional presence of giant icebergs during 5 consecutive years provided unprecedented habitat variation for testing the effects of extreme events on the relationship between SIC and foraging efficiency in this sea-ice dependent species. Significant levels of phenotypic plasticity were evident in response to changes in SIC in normal environmental conditions. Maximum foraging efficiency occurred at relatively low SIC, peaking at 6.1% and decreasing with higher SIC. The 'natural experiment' uncoupled efficiency levels from SIC variations. Our study suggests that lower summer SIC than currently observed would benefit the foraging performance of Adélie penguins in their southernmost breeding area. Importantly, it also provides evidence that extreme climatic events can disrupt response plasticity in a wild seabird population. This questions the predictive power of relationships built on past observations, when not only the average climatic conditions are changing but the frequency of extreme climatic anomalies is also on the rise.

  9. Antarctic climate change: extreme events disrupt plastic phenotypic response in Adélie penguins.

    PubMed

    Lescroël, Amélie; Ballard, Grant; Grémillet, David; Authier, Matthieu; Ainley, David G

    2014-01-01

    In the context of predicted alteration of sea ice cover and increased frequency of extreme events, it is especially timely to investigate plasticity within Antarctic species responding to a key environmental aspect of their ecology: sea ice variability. Using 13 years of longitudinal data, we investigated the effect of sea ice concentration (SIC) on the foraging efficiency of Adélie penguins (Pygoscelis adeliae) breeding in the Ross Sea. A 'natural experiment' brought by the exceptional presence of giant icebergs during 5 consecutive years provided unprecedented habitat variation for testing the effects of extreme events on the relationship between SIC and foraging efficiency in this sea-ice dependent species. Significant levels of phenotypic plasticity were evident in response to changes in SIC in normal environmental conditions. Maximum foraging efficiency occurred at relatively low SIC, peaking at 6.1% and decreasing with higher SIC. The 'natural experiment' uncoupled efficiency levels from SIC variations. Our study suggests that lower summer SIC than currently observed would benefit the foraging performance of Adélie penguins in their southernmost breeding area. Importantly, it also provides evidence that extreme climatic events can disrupt response plasticity in a wild seabird population. This questions the predictive power of relationships built on past observations, when not only the average climatic conditions are changing but the frequency of extreme climatic anomalies is also on the rise. PMID:24489657

  10. Antarctic Climate Change: Extreme Events Disrupt Plastic Phenotypic Response in Adélie Penguins

    PubMed Central

    Lescroël, Amélie; Ballard, Grant; Grémillet, David; Authier, Matthieu; Ainley, David G.

    2014-01-01

    In the context of predicted alteration of sea ice cover and increased frequency of extreme events, it is especially timely to investigate plasticity within Antarctic species responding to a key environmental aspect of their ecology: sea ice variability. Using 13 years of longitudinal data, we investigated the effect of sea ice concentration (SIC) on the foraging efficiency of Adélie penguins (Pygoscelis adeliae) breeding in the Ross Sea. A ‘natural experiment’ brought by the exceptional presence of giant icebergs during 5 consecutive years provided unprecedented habitat variation for testing the effects of extreme events on the relationship between SIC and foraging efficiency in this sea-ice dependent species. Significant levels of phenotypic plasticity were evident in response to changes in SIC in normal environmental conditions. Maximum foraging efficiency occurred at relatively low SIC, peaking at 6.1% and decreasing with higher SIC. The ‘natural experiment’ uncoupled efficiency levels from SIC variations. Our study suggests that lower summer SIC than currently observed would benefit the foraging performance of Adélie penguins in their southernmost breeding area. Importantly, it also provides evidence that extreme climatic events can disrupt response plasticity in a wild seabird population. This questions the predictive power of relationships built on past observations, when not only the average climatic conditions are changing but the frequency of extreme climatic anomalies is also on the rise. PMID:24489657

  11. Hydrological extremes and their agricultural impacts under a changing climate in Texas

    NASA Astrophysics Data System (ADS)

    Lee, K.; Gao, H.; Huang, M.; Sheffield, J.

    2015-12-01

    With the changing climate, hydrologic extremes (such as floods, droughts, and heat waves) are becoming more frequent and intensified. Such changes in extreme events are expected to affect agricultural production and food supplies. This study focuses on the State of Texas, which has the largest farm area and the highest value of livestock production in the U.S. The objectives are two-fold: First, to investigate the climatic impact on the occurrence of future hydrologic extreme events; and second, to evaluate the effects of the future extremes on agricultural production. The Variable Infiltration Capacity (VIC) model, which is calibrated and validated over Texas river basins during the historical period, is employed for this study. The VIC model is forced by the statistically downscaled climate projections from the Coupled Model Intercomparison Project Phase 5 (CMIP5) model ensembles at a spatial resolution of 1/8°. The CMIP5 projections contain four different scenarios in terms of Representative Concentration Pathway (RCP) (i.e. 2.6, 4.5, 6.0 and 8.5 w/m2). To carry out the analysis, VIC outputs forced by the CMIP5 model scenarios over three 30-year periods (1970-1999, 2020-2049 and 2070-2099) are first evaluated to identify how the frequency and the extent of the extreme events will be altered in the ten Texas major river basins. The results suggest that a significant increase in the number of extreme events will occur starting in the first half of the 21st century in Texas. Then, the effects of the predicted hydrologic extreme events on the irrigation water demand are investigated. It is found that future changes in water demand vary by crop type and location, with an east-to-west gradient. The results are expected to contribute to future water management and planning in Texas.

  12. Climate Extremes and Land-Use Change: Effects on Ecosystem Processes and Services

    NASA Astrophysics Data System (ADS)

    Bahn, Michael; Erb, Karlheinz; Hasibeder, Roland; Mayr, Stefan; Niedertscheider, Maria; Oberhuber, Walter; Tappeiner, Ulrike; Tasser, Erich; Viovy, Nicolas; Wieser, Gerhard

    2016-04-01

    Extreme climatic events, in particular droughts and heatwaves, have significant impacts on ecosystem carbon and water cycles and a range of related ecosystem services. It is expected that in the coming decades the return intervals and severities of extreme droughts will increase substantially and may result in the passing of thresholds of ecosystem functioning, potentially causing legacy effects, which are so far poorly understood. Observational evidence suggests that different land cover types (forest, grassland) are differently influenced by extreme drought, but there is a lack of knowledge whether and how future, increasingly severe climate extremes will affect their concurrent and lagged responses, as well as land-use decisions determining future shifts in land cover. The ClimLUC project aims to understand how extreme summer drought affects carbon and water dynamics of mountain ecosystems under different land uses, and to analyse implications for ecosystem service provisioning. Overall, we hypothesize that land-use change alters the effects of extreme summer drought on ecosystem processes and the related services, grassland responding more rapidly and strongly but being more resilient to extreme drought than forest. To address the aims and hypotheses, we will 1) test experimentally how (a) a managed, (b) an abandoned mountain grassland and (c) an adjacent subalpine forest respond to a progressive extreme drought and will analyse threshold responses of carbon and water dynamics and their implications for ecosystem services (timber and fodder production, carbon sequestration, water provisioning); 2) quantify carry-over effects of the extreme event on ecosystem processes and services; 3) project and attribute future carbon and water cycle responses to extreme drought and related socio-economic changes, based on a process-based dynamic general vegetation model; 4) analyse the interrelation between land-use changes and the occurrence and severity of past and future

  13. Analysis of climate variability in mainland Portugal using a combined Climate Extremes Index

    NASA Astrophysics Data System (ADS)

    Espírito Santo, Fátima; de Lima, Isabel P.

    2014-05-01

    Monitoring changes in climate extremes is important because of their potential severe impacts on the environment and the society. Due to its geographical situation, mainland Portugal shows important spatial gradients in precipitation and air temperature and is prone to the occurrence of extreme weather and climate events, such as heat waves, droughts and floods. Thus, there is a need to understand regional specificities in the changes of occurrence of these events in the territory that could require special attention in the prospect of operational climate change adaptation and mitigation measures, to be adopted at the regional scale. For this purpose, a modified combined Climate Extremes Index (CEI) is proposed here, for mainland Portugal. This index consists of five component indicators of air temperature and precipitation extremes and was developed to measure the percentage of area affected by these extremes. Therefore, we use this index to analyse changes in the fraction of the country experiencing extremes (cold, hot, dry, wet), at the annual and seasonal scales, after 1941. At the annual scale, results show an increase in the extent of hot and dry extremes and a decrease in the extent of cold and wet extremes over the whole country, although only the results obtained for the air temperature are statistically significant. Since the mid-1970s, the fraction of the area of mainland Portugal experiencing maximum and minimum temperatures much above normal has increased significantly. An increasing trend in the area experiencing drought conditions and with a much greater-than-normal number of dry days is also noted in the last decades. At the seasonal scale, spring, summer and winter show a significant increase in the extent of hot extremes and a decrease in the extent of cold extremes. For all seasons, the fraction of the area experiencing drought conditions increased, whereas in spring and autumn the fraction of the area experiencing wet conditions decreased. In

  14. Global trends in extreme precipitation: climate models versus observations

    NASA Astrophysics Data System (ADS)

    Asadieh, B.; Krakauer, N. Y.

    2015-02-01

    Precipitation events are expected to become substantially more intense under global warming, but few global comparisons of observations and climate model simulations are available to constrain predictions of future changes in precipitation extremes. We present a systematic global-scale comparison of changes in historical (1901-2010) annual-maximum daily precipitation between station observations (compiled in HadEX2) and the suite of global climate models contributing to the fifth phase of the Coupled Model Intercomparison Project (CMIP5). We use both parametric and non-parametric methods to quantify the strength of trends in extreme precipitation in observations and models, taking care to sample them spatially and temporally in comparable ways. We find that both observations and models show generally increasing trends in extreme precipitation since 1901, with the largest changes in the deep tropics. Annual-maximum daily precipitation (Rx1day) has increased faster in the observations than in most of the CMIP5 models. On a global scale, the observational annual-maximum daily precipitation has increased by an average of 5.73 mm over the last 110 years, or 8.5% in relative terms. This corresponds to an increase of 10% K-1 in global warming since 1901, which is larger than the average of climate models, with 8.3% K-1. The average rate of increase in extreme precipitation per K of warming in both models and observations is higher than the rate of increase in atmospheric water vapor content per K of warming expected from the Clausius-Clapeyron equation. We expect our findings to help inform assessments of precipitation-related hazards such as flooding, droughts and storms.

  15. Attribution of extreme weather and climate events overestimated by unreliable climate simulations

    NASA Astrophysics Data System (ADS)

    Bellprat, Omar; Doblas-Reyes, Francisco

    2016-03-01

    Event attribution aims to estimate the role of an external driver after the occurrence of an extreme weather and climate event by comparing the probability that the event occurs in two counterfactual worlds. These probabilities are typically computed using ensembles of climate simulations whose simulated probabilities are known to be imperfect. The implications of using imperfect models in this context are largely unknown, limited by the number of observed extreme events in the past to conduct a robust evaluation. Using an idealized framework, this model limitation is studied by generating large number of simulations with variable reliability in simulated probability. The framework illustrates that unreliable climate simulations are prone to overestimate the attributable risk to climate change. Climate model ensembles tend to be overconfident in their representation of the climate variability which leads to systematic increase in the attributable risk to an extreme event. Our results suggest that event attribution approaches comprising of a single climate model would benefit from ensemble calibration in order to account for model inadequacies similarly as operational forecasting systems.

  16. Space based observations for monitoring extreme weather and climate events

    SciTech Connect

    Rao, P.K.

    1996-12-31

    Observations are essential for monitoring, understanding, and predicting the potential for extreme weather and climate events. These events occur on all time and spatial scales. Current NOAA operational satellites have a unique capability of providing many of the observations that are critical for monitoring these events. These observations and derived geophysical quantities can also be used for diagnostics and prediction purposes. Extreme weather conditions such as severe thunderstorms and flash floods, occur very quickly, may last for a short time, and create a considerable amount of damage. Advance warnings of the order of a few minutes are needed to alert the public so they may take adequate precautions. Some extreme weather conditions such as tropical storms (hurricanes) may last for days, and in order to predict the exact track, intensity of the storm and forecast the land fall, frequent observations are critical. Examples of satellite data that are obtained from the NOAA satellites are presented to demonstrate their ability to monitor the extreme weather phenomena. Examples of extreme climate conditions are droughts over continents and the annual depletion of ozone over the Antarctic. Data derived from NOAA satellites were used to monitor the severe drought over Texas and Southwestern U.S.A. in early 1996. Similar data are being used by other countries to monitor the drought in their regions. The development of the ozone hole over the Antarctic during the last fifteen years has been a major scientific and environmental concern. Data from NOAA operational satellites have been extensively used to show the yearly development and dissipation of the ozone hole during the Southern Hemisphere springtime.

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

    PubMed

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

    2014-12-01

    extreme events can also alter the ecosystem succession process, even resulting in an alternative trajectory. All of these findings could improve our understanding of the impacts of climate change on the provision of ecosystem functions and services and can also provide a basis for policy makers to apply adaptive measures to overcome the unfavorable influence of climate change.

  18. Urban climate effects on extreme temperatures in Madison, Wisconsin, USA

    NASA Astrophysics Data System (ADS)

    Schatz, Jason; Kucharik, Christopher J.

    2015-09-01

    As climate change increases the frequency and intensity of extreme heat, cities and their urban heat island (UHI) effects are growing, as are the urban populations encountering them. These mutually reinforcing trends present a growing risk for urban populations. However, we have limited understanding of urban climates during extreme temperature episodes, when additional heat from the UHI may be most consequential. We observed a historically hot summer and historically cold winter using an array of up to 150 temperature and relative humidity sensors in and around Madison, Wisconsin, an urban area of population 402 000 surrounded by lakes and a rural landscape of agriculture, forests, wetlands, and grasslands. In the summer of 2012 (third hottest since 1869), Madison’s urban areas experienced up to twice as many hours ⩾32.2 °C (90 °F), mean July TMAX up to 1.8 °C higher, and mean July TMIN up to 5.3 °C higher than rural areas. During a record setting heat wave, dense urban areas spent over four consecutive nights above the National Weather Service nighttime heat stress threshold of 26.7 °C (80 °F), while rural areas fell below 26.7 °C nearly every night. In the winter of 2013-14 (coldest in 35 years), Madison’s most densely built urban areas experienced up to 40% fewer hours ⩽-17.8 °C (0 °F), mean January TMAX up to 1 °C higher, and mean January TMIN up to 3 °C higher than rural areas. Spatially, the UHI tended to be most intense in areas with higher population densities. Temporally, both daytime and nighttime UHIs tended to be slightly more intense during more-extreme heat days compared to average summer days. These results help us understand the climates for which cities must prepare in a warming, urbanizing world.

  19. Climate Change, Extreme Weather Events, and Human Health Implications in the Asia Pacific Region.

    PubMed

    Hashim, Jamal Hisham; Hashim, Zailina

    2016-03-01

    The Asia Pacific region is regarded as the most disaster-prone area of the world. Since 2000, 1.2 billion people have been exposed to hydrometeorological hazards alone through 1215 disaster events. The impacts of climate change on meteorological phenomena and environmental consequences are well documented. However, the impacts on health are more elusive. Nevertheless, climate change is believed to alter weather patterns on the regional scale, giving rise to extreme weather events. The impacts from extreme weather events are definitely more acute and traumatic in nature, leading to deaths and injuries, as well as debilitating and fatal communicable diseases. Extreme weather events include heat waves, cold waves, floods, droughts, hurricanes, tropical cyclones, heavy rain, and snowfalls. Globally, within the 20-year period from 1993 to 2012, more than 530 000 people died as a direct result of almost 15 000 extreme weather events, with losses of more than US$2.5 trillion in purchasing power parity. PMID:26377857

  20. Extreme Rivers for Future Climates - Simulation Using Spatial Weather Generator

    NASA Astrophysics Data System (ADS)

    Kuchar, Leszek; Kosierb, Ryszard; Iwański, Sławomir; Jelonek, Leszek

    2014-05-01

    -80 years. The probability distribution of the extreme river flow gives detailed information on the moment characteristics, confidence intervals and critical values. It is an important tool for a decision support system. In case of extreme daily flow in the Kaczawa River, the catchment shows significant changes depending on the climate change scenario and time to lead. REFERENCES Iwanski, S. and L. Kuchar (2003). Spatial generation of daily meteorological data. Acta Scientiarum Polonorum - Formatio Circumiectu, 2(1): 113-121 (in Polish). Katz, R.W. (1996). Use of conditional stochastic models to generate climate change scenarios. Clim. Change, 35: 397-414. Walpole R.E., Myers R.H., Myers S.L. and K. Ye (2002). Probability and statistics for engineers and scientists. Prentice Hall, 7th Ed., New Jersey.

  1. Land cover change drives climate extremes and aridity in non-Amazonian South America

    NASA Astrophysics Data System (ADS)

    Larsen, J.; Salazar, A.; Mcalpine, C. A.; Syktus, J.; Katzfey, J.

    2015-12-01

    Increasing evidence is showing the relevance of land cover change on the regional mean climate. However, the mechanisms that explain these interactions remain a challenge in land - atmosphere interactions science. This challenge is particularly significant in understanding the role of vegetation change on climate extremes and aridity, which has been barely addressed by the literature. In this paper we focus on this gap by investigating the effects of land use and land cover change on selected climate extremes indices and aridity in non-Amazonian South America over an area of about 3 million km2. We run a 3 ensemble climate model nudged with the ERA-Interim reanalysis and stretched to 25 km resolution for present (year 2005) land cover relative to realistic historic vegetation distribution. The most important results of this experiment are that the degree of change in vegetation structure determines whether extreme daytime temperatures will increase or decrease, particularly during the dry season. This is because a large change in surface roughness promotes increased wind speeds and heat advection, whereas a small change in surface roughness does not increase wind and can increase heat build-up in the atmosphere since the sensible heat flux also increases. We also put these results in a wider context of land surface - atmospheric feedbacks by looking at the corresponding change in aridity (precipitation / potential evapotranspiration). This shows the processes that drive the changes in temperature extremes also determine whether significant changes in aridity occur, since all the change in aridity can be prescribed to changes in potential evaporation, or atmospheric water demand. We propose a conceptual model of the mechanisms that explain these alterations which is an advance in understanding land-atmosphere interactions and provides evidence of the main mechanisms responsible of changes in the feedbacks because of changes in natural vegetation.

  2. Urban Heat Island phenomenon in extreme continental climate (Astana, Kazakhstan)

    NASA Astrophysics Data System (ADS)

    Konstantinov, Pavel; Akhmetova, Alina

    2015-04-01

    Urban Heat Island (UHI) phenomenon is well known in scientific literature since first half of the 19th century [1]. By now a wide number of world capitals is described from climatological point of view, especially in mid-latitudes. In beginning of XXI century new studies focus on heat island of tropical cities. However dynamics UHI in extreme continental climates is insufficiently investigated, due to the fact that there isn't large cities in Europe and Northern America within that climate type. In this paper we investigate seasonal and diurnal dynamics UHI intensity for Astana, capital city of Kazakhstan (population larger than 835 000 within the city) including UHI intensity changes on different time scales. Now (since 1998) Astana is the second coldest capital city in the world after Ulaanbaatar, Mongolia [3] For this study we use the UHI investigation technology, described in [2]. According to this paper, we selected three stations: one located into city in high and midrise buildings area (including extensive lowrise and high-energy industrial - LCZ classification) and two others located in rural site (sparsely built or open-set and lightweight lowrise according LCZ classification). Also these stations must be close by distance (less than 100 km) and altitude. Therefore, first for Astana city were obtained numerical evaluations for UHI climate dynamics, UHI dependence of synoptic situations and total UHI climatology on monthly and daily averages. References: 1.Howard, L. (1833) The Climate of London, Deduced from Meteorological Observations. Volume 2, London. 2.Kukanova E.A., Konstantinov P.I. An urban heat islands climatology in Russia and linkages to the climate change In Geophysical Research Abstracts, volume 16 of EGU General Assembly, pages EGU2014-10833-1, Germany, 2014. Germany. 3.www.pogoda.ru.net

  3. Cyclones and extreme windstorm events over Europe under climate change: Global and regional climate model diagnostics

    NASA Astrophysics Data System (ADS)

    Leckebusch, G. C.; Ulbrich, U.

    2003-04-01

    More than any changes of the climate system mean state conditions, the development of extreme events may influence social, economic and legal aspects of our society. This linkage results from the impact of extreme climate events (natural hazards) on environmental systems which again are directly linked to human activities. Prominent examples from the recent past are the record breaking rainfall amounts of August 2002 in central Europe which produced widespread floodings or the wind storm Lothar of December 1999. Within the MICE (Modelling the Impact of Climate Extremes) project framework an assessment of the impact of changes in extremes will be done. The investigation is carried out for several different impact categories as agriculture, energy use and property damage. Focus is laid on the diagnostics of GCM and RCM simulations under different climate change scenarios. In this study we concentrate on extreme windstorms and their relationship to cyclone activity in the global HADCM3 as well as in the regional HADRM3 model under two climate change scenarios (SRESA2a, B2a). In order to identify cyclones we used an objective algorithm from Murry and Simmonds which was widely tested under several different conditions. A slight increase in the occurrence of systems is identified above northern parts of central Europe for both scenarios. For more severe systems (core pressure < 990 hPa) we find an increase for western Europe. Strong wind events can be defined via different percentile values of the windspeed (e.g. above the 95 percentile). By this means the relationship between strong wind events and cyclones is also investigated. For several regions (e.g. Germany, France, Spain) a shift to more deep cyclones connected with an increasing number of strong wind events is found.

  4. Extreme Weather Events and Interconnected Infrastructures: Toward More Comprehensive Climate Change Planning

    DOE PAGES

    Wilbanks, Thomas J.; Fernandez, Steven J.; Allen, Melissa R.

    2015-06-23

    The President s Climate Change Action Plan calls for the development of better science, data, and tools for climate preparedness. Many of the current questions about preparedness for extreme weather events in coming decades are, however, difficult to answer with assets that have been developed by climate science to answer longer-term questions about climate change. Capacities for projecting exposures to climate-related extreme events, along with their implications for interconnected infrastructures, are now emerging.

  5. Bayesian analysis for extreme climatic events: A review

    NASA Astrophysics Data System (ADS)

    Chu, Pao-Shin; Zhao, Xin

    2011-11-01

    This article reviews Bayesian analysis methods applied to extreme climatic data. We particularly focus on applications to three different problems related to extreme climatic events including detection of abrupt regime shifts, clustering tropical cyclone tracks, and statistical forecasting for seasonal tropical cyclone activity. For identifying potential change points in an extreme event count series, a hierarchical Bayesian framework involving three layers - data, parameter, and hypothesis - is formulated to demonstrate the posterior probability of the shifts throughout the time. For the data layer, a Poisson process with a gamma distributed rate is presumed. For the hypothesis layer, multiple candidate hypotheses with different change-points are considered. To calculate the posterior probability for each hypothesis and its associated parameters we developed an exact analytical formula, a Markov Chain Monte Carlo (MCMC) algorithm, and a more sophisticated reversible jump Markov Chain Monte Carlo (RJMCMC) algorithm. The algorithms are applied to several rare event series: the annual tropical cyclone or typhoon counts over the central, eastern, and western North Pacific; the annual extremely heavy rainfall event counts at Manoa, Hawaii; and the annual heat wave frequency in France. Using an Expectation-Maximization (EM) algorithm, a Bayesian clustering method built on a mixture Gaussian model is applied to objectively classify historical, spaghetti-like tropical cyclone tracks (1945-2007) over the western North Pacific and the South China Sea into eight distinct track types. A regression based approach to forecasting seasonal tropical cyclone frequency in a region is developed. Specifically, by adopting large-scale environmental conditions prior to the tropical cyclone season, a Poisson regression model is built for predicting seasonal tropical cyclone counts, and a probit regression model is alternatively developed toward a binary classification problem. With a non

  6. Relating Regional Arctic Sea Ice and climate extremes over Europe

    NASA Astrophysics Data System (ADS)

    Ionita-Scholz, Monica; Grosfeld, Klaus; Lohmann, Gerrit; Scholz, Patrick

    2016-04-01

    The potential increase of temperature extremes under climate change is a major threat to society, as temperature extremes have a deep impact on environment, hydrology, agriculture, society and economy. Hence, the analysis of the mechanisms underlying their occurrence, including their relationships with the large-scale atmospheric circulation and sea ice concentration, is of major importance. At the same time, the decline in Arctic sea ice cover during the last 30 years has been widely documented and it is clear that this change is having profound impacts at regional as well as planetary scale. As such, this study aims to investigate the relation between the autumn regional sea ice concentration variability and cold winters in Europe, as identified by the numbers of cold nights (TN10p), cold days (TX10p), ice days (ID) and consecutive frost days (CFD). We analyze the relationship between Arctic sea ice variation in autumn (September-October-November) averaged over eight different Arctic regions (Barents/Kara Seas, Beaufort Sea, Chukchi/Bering Seas, Central Arctic, Greenland Sea, Labrador Sea/Baffin Bay, Laptev/East Siberian Seas and Northern Hemisphere) and variations in atmospheric circulation and climate extreme indices in the following winter season over Europe using composite map analysis. Based on the composite map analysis it is shown that the response of the winter extreme temperatures over Europe is highly correlated/connected to changes in Arctic sea ice variability. However, this signal is not symmetrical for the case of high and low sea ice years. Moreover, the response of temperatures extreme over Europe to sea ice variability over the different Arctic regions differs substantially. The regions which have the strongest impact on the extreme winter temperature over Europe are: Barents/Kara Seas, Beaufort Sea, Central Arctic and the Northern Hemisphere. For the years of high sea ice concentration in the Barents/Kara Seas there is a reduction in the number

  7. How shorter black carbon lifetime alters its climate effect.

    PubMed

    Hodnebrog, Øivind; Myhre, Gunnar; Samset, Bjørn H

    2014-01-01

    Black carbon (BC), unlike most aerosol types, absorbs solar radiation. However, the quantification of its climate impact is uncertain and presently under debate. Recently, attention has been drawn both to a likely underestimation of global BC emissions in climate models, and an overestimation of BC at high altitudes. Here we show that doubling present day BC emissions in a model simulation, while reducing BC lifetime based on observational evidence, leaves the direct aerosol effect of BC virtually unchanged. Increased emissions, together with increased wet removal that reduces the lifetime, yields modelled BC vertical profiles that are in strongly improved agreement with recent aircraft observations. Furthermore, we explore the consequences of an altered BC profile in a global circulation model, and show that both the vertical profile of BC and rapid climate adjustments need to be taken into account in order to assess the total climate impact of BC. PMID:25255429

  8. How shorter black carbon lifetime alters its climate effect.

    PubMed

    Hodnebrog, Øivind; Myhre, Gunnar; Samset, Bjørn H

    2014-09-25

    Black carbon (BC), unlike most aerosol types, absorbs solar radiation. However, the quantification of its climate impact is uncertain and presently under debate. Recently, attention has been drawn both to a likely underestimation of global BC emissions in climate models, and an overestimation of BC at high altitudes. Here we show that doubling present day BC emissions in a model simulation, while reducing BC lifetime based on observational evidence, leaves the direct aerosol effect of BC virtually unchanged. Increased emissions, together with increased wet removal that reduces the lifetime, yields modelled BC vertical profiles that are in strongly improved agreement with recent aircraft observations. Furthermore, we explore the consequences of an altered BC profile in a global circulation model, and show that both the vertical profile of BC and rapid climate adjustments need to be taken into account in order to assess the total climate impact of BC.

  9. Drought, deluge and declines: the impact of precipitation extremes on amphibians in a changing climate

    USGS Publications Warehouse

    Walls, Susan C.; Barichivich, William J.; Brown, Mary E.

    2013-01-01

    The Class Amphibia is one of the most severely impacted taxa in an on-going global biodiversity crisis. Because amphibian reproduction is tightly associated with the presence of water, climatic changes that affect water availability pose a particularly menacing threat to both aquatic and terrestrial-breeding amphibians. We explore the impacts that one facet of climate change—that of extreme variation in precipitation—may have on amphibians. This variation is manifested principally as increases in the incidence and severity of both drought and major storm events. We stress the need to consider not only total precipitation amounts but also the pattern and timing of rainfall events. Such rainfall “pulses” are likely to become increasingly more influential on amphibians, especially in relation to seasonal reproduction. Changes in reproductive phenology can strongly influence the outcome of competitive and predatory interactions, thus potentially altering community dynamics in assemblages of co-existing species. We present a conceptual model to illustrate possible landscape and metapopulation consequences of alternative climate change scenarios for pond-breeding amphibians, using the Mole Salamander, Ambystoma talpoideum, as an example. Although amphibians have evolved a variety of life history strategies that enable them to cope with environmental uncertainty, it is unclear whether adaptations can keep pace with the escalating rate of climate change. Climate change, especially in combination with other stressors, is a daunting challenge for the persistence of amphibians and, thus, the conservation of global biodiversity.

  10. Drought, deluge and declines: the impact of precipitation extremes on amphibians in a changing climate.

    PubMed

    Walls, Susan C; Barichivich, William J; Brown, Mary E

    2013-03-11

    The Class Amphibia is one of the most severely impacted taxa in an on-going global biodiversity crisis. Because amphibian reproduction is tightly associated with the presence of water, climatic changes that affect water availability pose a particularly menacing threat to both aquatic and terrestrial-breeding amphibians. We explore the impacts that one facet of climate change-that of extreme variation in precipitation-may have on amphibians. This variation is manifested principally as increases in the incidence and severity of both drought and major storm events. We stress the need to consider not only total precipitation amounts but also the pattern and timing of rainfall events. Such rainfall "pulses" are likely to become increasingly more influential on amphibians, especially in relation to seasonal reproduction. Changes in reproductive phenology can strongly influence the outcome of competitive and predatory interactions, thus potentially altering community dynamics in assemblages of co-existing species. We present a conceptual model to illustrate possible landscape and metapopulation consequences of alternative climate change scenarios for pond-breeding amphibians, using the Mole Salamander, Ambystoma talpoideum, as an example. Although amphibians have evolved a variety of life history strategies that enable them to cope with environmental uncertainty, it is unclear whether adaptations can keep pace with the escalating rate of climate change. Climate change, especially in combination with other stressors, is a daunting challenge for the persistence of amphibians and, thus, the conservation of global biodiversity.

  11. Drought, Deluge and Declines: The Impact of Precipitation Extremes on Amphibians in a Changing Climate

    PubMed Central

    Walls, Susan C.; Barichivich, William J.; Brown, Mary E.

    2013-01-01

    The Class Amphibia is one of the most severely impacted taxa in an on-going global biodiversity crisis. Because amphibian reproduction is tightly associated with the presence of water, climatic changes that affect water availability pose a particularly menacing threat to both aquatic and terrestrial-breeding amphibians. We explore the impacts that one facet of climate change—that of extreme variation in precipitation—may have on amphibians. This variation is manifested principally as increases in the incidence and severity of both drought and major storm events. We stress the need to consider not only total precipitation amounts but also the pattern and timing of rainfall events. Such rainfall “pulses” are likely to become increasingly more influential on amphibians, especially in relation to seasonal reproduction. Changes in reproductive phenology can strongly influence the outcome of competitive and predatory interactions, thus potentially altering community dynamics in assemblages of co-existing species. We present a conceptual model to illustrate possible landscape and metapopulation consequences of alternative climate change scenarios for pond-breeding amphibians, using the Mole Salamander, Ambystoma talpoideum, as an example. Although amphibians have evolved a variety of life history strategies that enable them to cope with environmental uncertainty, it is unclear whether adaptations can keep pace with the escalating rate of climate change. Climate change, especially in combination with other stressors, is a daunting challenge for the persistence of amphibians and, thus, the conservation of global biodiversity. PMID:24832668

  12. Drought, deluge and declines: the impact of precipitation extremes on amphibians in a changing climate.

    PubMed

    Walls, Susan C; Barichivich, William J; Brown, Mary E

    2013-01-01

    The Class Amphibia is one of the most severely impacted taxa in an on-going global biodiversity crisis. Because amphibian reproduction is tightly associated with the presence of water, climatic changes that affect water availability pose a particularly menacing threat to both aquatic and terrestrial-breeding amphibians. We explore the impacts that one facet of climate change-that of extreme variation in precipitation-may have on amphibians. This variation is manifested principally as increases in the incidence and severity of both drought and major storm events. We stress the need to consider not only total precipitation amounts but also the pattern and timing of rainfall events. Such rainfall "pulses" are likely to become increasingly more influential on amphibians, especially in relation to seasonal reproduction. Changes in reproductive phenology can strongly influence the outcome of competitive and predatory interactions, thus potentially altering community dynamics in assemblages of co-existing species. We present a conceptual model to illustrate possible landscape and metapopulation consequences of alternative climate change scenarios for pond-breeding amphibians, using the Mole Salamander, Ambystoma talpoideum, as an example. Although amphibians have evolved a variety of life history strategies that enable them to cope with environmental uncertainty, it is unclear whether adaptations can keep pace with the escalating rate of climate change. Climate change, especially in combination with other stressors, is a daunting challenge for the persistence of amphibians and, thus, the conservation of global biodiversity. PMID:24832668

  13. Changes in weather and climate extremes over Korea and possible causes: A review

    NASA Astrophysics Data System (ADS)

    Min, Seung-Ki; Son, Seok-Woo; Seo, Kyong-Hwan; Kug, Jong-Seong; An, Soon-Il; Choi, Yong-Sang; Jeong, Jee-Hoon; Kim, Baek-Min; Kim, Ji-Won; Kim, Yeon-Hee; Lee, June-Yi; Lee, Myong-In

    2015-05-01

    Weather and climate extremes exert devastating influence on human society and ecosystem around the world. Recent observations show increase in frequency and intensity of climate extremes around the world including East Asia. In order to assess current status of the observed changes in weather and climate extremes and discuss possible mechanisms, this study provides an overview of recent analyses on such extremes over Korea and East Asia. It is found that the temperature extremes over the Korean Peninsula exhibit long-term warming trends with more frequent hot events and less frequent cold events, along with sizeable interannual and decadal variabilities. The comprehensive review on the previous literature further suggests that the weather and climate extremes over East Asia can be affected by several climate factors of external and internal origins. It has been assessed that greenhouse warming leads to increase in warm extremes and decrease in cold extremes over East Asia, but recent Arctic sea-ice melting and associated warming tends to bring cold snaps to East Asia during winter. Internal climate variability such as tropical intraseasonal oscillation and El Niño-Southern Oscillation can also exert considerable impacts on weather and climate extremes over Korea and East Asia. It is, however, noted that our current understanding is far behind to estimate the effect of these climate factors on local weather and climate extremes in a quantitative sense.

  14. Sea Extremes: Integrated impact assessment in coastal climate adaptation

    NASA Astrophysics Data System (ADS)

    Sorensen, Carlo; Knudsen, Per; Broge, Niels; Molgaard, Mads; Andersen, Ole

    2016-04-01

    We investigate effects of sea level rise and a change in precipitation pattern on coastal flooding hazards. Historic and present in situ and satellite data of water and groundwater levels, precipitation, vertical ground motion, geology, and geotechnical soil properties are combined with flood protection measures, topography, and infrastructure to provide a more complete picture of the water-related impact from climate change at an exposed coastal location. Results show that future sea extremes evaluated from extreme value statistics may, indeed, have a large impact. The integrated effects from future storm surges and other geo- and hydro-parameters need to be considered in order to provide for the best protection and mitigation efforts, however. Based on the results we present and discuss a simple conceptual model setup that can e.g. be used for 'translation' of regional sea level rise evidence and projections to concrete impact measures. This may be used by potentially affected stakeholders -often working in different sectors and across levels of governance, in a common appraisal of the challenges faced ahead. The model may also enter dynamic tools to evaluate local impact as sea level research advances and projections for the future are updated.

  15. Dynamical downscaling of present climate extremal episodes for the BINGO research site of Cyprus

    NASA Astrophysics Data System (ADS)

    Zittis, George; Hadjinicolaou, Panos; Bruggeman, Adriana; Camera, Corrado; Lelieveld, Jos

    2016-04-01

    Besides global warming, climate change is expected to cause alterations in precipitation amounts and distribution than can be linked to extreme events such as floods or prolonged droughts. This will have a significant impact in strategic societal sectors that base their activities on water resources. While the global climate projections inform us about the long-term and weather forecasts can give useful information only for a few days or weeks, decision-makers and end-users also need guidance on inter-annual to decadal time scales. In this context, the BINGO (Bringing INnovation to onGOing water management - a better future under climate change) H2020 project aims both at reducing the uncertainty of near-term climate predictions and developing response strategies in order to better manage the remaining uncertainty. One of the project's main objectives is to develop improved decadal predictions, in adequate spatiotemporal scales, with a specific focus on extreme precipitation events. The projected rainfall will be eventually used to drive hydrological impact models. BINGO focuses on research sites that encompass river basins, watersheds and urban areas of six European countries including Norway, Cyprus, Germany, Portugal, The Netherlands and Spain. In this study we present the dynamical downscaling of the ERA-Interim dataset for validation purposes and for the research site of Cyprus. Five extreme rainfall periods were identified from the observed precipitation archives and were simulated in very high horizontal resolutions (4~1 km) using the WRF limited area atmospheric model. To optimize the performance of the model we have tested a combination of three cumulus and five microphysics parameterization schemes that resulted in 15 simulations for each extreme precipitation event. The model output was compared with daily or hourly (where available) representative rain gauge data. A set of statistical metrics was applied in order to objectively select the best

  16. Key ecological responses to nitrogen are altered by climate change

    USGS Publications Warehouse

    Greaver, T.L.; Clark, C.M.; Compton, J.E.; Vallano, D.; Talhelm, A. F.; Weaver, C.P.; Band, L.E.; Baron, J. S.; Davidson, E.A.; Tague, C.L.; Felker-Quinn, E.; Lynch, J.A.; Herrick, J.D.; Liu, L.; Goodale, C.L.; Novak, K. J.; Haeuber, R. A.

    2016-01-01

    Climate change and anthropogenic nitrogen deposition are both important ecological threats. Evaluating their cumulative effects provides a more holistic view of ecosystem vulnerability to human activities, which would better inform policy decisions aimed to protect the sustainability of ecosystems. Our knowledge of the cumulative effects of these stressors is growing, but we lack an integrated understanding. In this Review, we describe how climate change alters key processes in terrestrial and freshwater ecosystems related to nitrogen cycling and availability, and the response of ecosystems to nitrogen addition in terms of carbon cycling, acidification and biodiversity.

  17. Key ecological responses to nitrogen are altered by climate change

    NASA Astrophysics Data System (ADS)

    Greaver, T. L.; Clark, C. M.; Compton, J. E.; Vallano, D.; Talhelm, A. F.; Weaver, C. P.; Band, L. E.; Baron, J. S.; Davidson, E. A.; Tague, C. L.; Felker-Quinn, E.; Lynch, J. A.; Herrick, J. D.; Liu, L.; Goodale, C. L.; Novak, K. J.; Haeuber, R. A.

    2016-09-01

    Climate change and anthropogenic nitrogen deposition are both important ecological threats. Evaluating their cumulative effects provides a more holistic view of ecosystem vulnerability to human activities, which would better inform policy decisions aimed to protect the sustainability of ecosystems. Our knowledge of the cumulative effects of these stressors is growing, but we lack an integrated understanding. In this Review, we describe how climate change alters key processes in terrestrial and freshwater ecosystems related to nitrogen cycling and availability, and the response of ecosystems to nitrogen addition in terms of carbon cycling, acidification and biodiversity.

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

    NASA Astrophysics Data System (ADS)

    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

  19. GCMs-based spatiotemporal evolution of climate extremes during the 21st century in China

    NASA Astrophysics Data System (ADS)

    Li, Jianfeng; Zhang, Qiang; Chen, Yongqin David; Singh, Vijay P.

    2013-10-01

    Changes in the hydrological cycle being caused by human-induced global warming are triggering variations in observed spatiotemporal distributions of precipitation and temperature extremes, and hence in droughts and floods across China. Evaluation of future climate extremes based on General Circulation Models (GCMs) outputs will be of great importance in scientific management of water resources and agricultural activities. In this study, five precipitation extreme and five temperature extreme indices are defined. This study analyzes daily precipitation and temperature data for 1960-2005 from 529 stations in China and outputs of GCMs from the Coupled Model Intercomparison Project Phase 3 (CMIP3) and Phase 5 (CMIP5). Downscaling methods, based on QQ-plot and transfer functions, are used to downscale GCMs outputs to the site scale. Performances of GCMs in simulating climate extremes were evaluated using the Taylor diagram. Results showed that: (1) the multimodel CMIP5 ensemble performs the best in simulating observed extreme conditions; (2) precipitation processes are intensifying with increased frequency and intensity across entire China. The southwest China, however, is dominated by lengthening maximum consecutive dry days and also more heavy precipitation extremes; (3) warming processes continue with increasing warm nights, decreasing frost days, and lengthening heat waves during the 21st century; (4) changes in precipitation and temperature extremes exhibit larger changing magnitudes under RCP85 scenario; (5) for the evolution of changes in extremes, in most cases, the spatial pattern keeps the same, even though changing rates vary. In some cases, area with specific changing properties extends or shrinks gradually. The directions of trends may alter during the evolution; and (6) changes under RCP85 become more and more pronounced as time elapses. Under the peak-and-decline RCP26, changes in some cases do not decrease correspondingly during 2070-2099 even though the

  20. Cosmic Rays, the Black Pole and Extreme Climate.

    NASA Astrophysics Data System (ADS)

    Ely, J.

    2001-04-01

    The Magnetic Coupling Model predicts many climate anomalies due to solar oscillations (from gravitational torque impulses), galactic cosmic ray modulations, etc, back thru the Pleistocene. A major process in this era is Hale cycle reconnection of solar and galactic B, causing strong recurring "Cirrus Holes." These: shift pressure centers, making drought cycles, record floods, etc; disguised global warming (causing disunity on its reality) by high contrast (deglaciating) climate in the northern hemisphere in alternate sunspot cycles. Fossil fuel CO2 ended major ice ages and risks imminent rapid (decade) CO2 runaway via sea surface exchange (see refs: Ely, Session A8, APS Mtg March 2001; Bette Hileman, Chem Eng News 9, Apr 24, 2000; Ely, Proc. IEEE Conf. Oceans '91, 3: 1658-1665, 1991) Polar regions warm much more in summer than the global averages and now, having lost snow cover, in the Arctic radiate as a black body in winter becoming extremely cold. Hence, altho the record highest average first quarter year US temperature was in April 2000, the most severe US winter ever recorded began in Nov, due to polar breakthrough. Using fossil fuel to survive the winter, hastens the 6m sea level rise.

  1. Climate change and the impact of extreme temperatures on aviation

    NASA Astrophysics Data System (ADS)

    Coffel, E.; Horton, R.

    2014-12-01

    Weather is the most significant factor affecting aircraft operations, accounting for 70-80% of passenger delays and costing airlines hundreds of millions of dollars per year in lost revenue. Temperature and airport elevation significantly influence the maximum allowable takeoff weight of an aircraft by changing the surface air density and thus the lift produced at a given speed. For a given runway length, airport elevation, and aircraft type there is a temperature threshold above which the airplane cannot take off at its maximum weight and thus must be weight restricted. The number of summer days necessitating weight restriction has increased since 1980 along with the observed increase in surface temperature. Climate change is projected to increase mean temperatures at all airports and significantly increase the frequency and severity of extreme heat events at some. These changes will negatively affect aircraft performance, leading to increased weight restrictions especially at airports with short runways and little room to expand. For a Boeing 737-800 aircraft, we find that the number of weight restriction days between May and September will increase by 50-100% at four major airports in the United States by 2050-2070 under the RCP8.5 high emissions scenario. These performance reductions may have a significant economic effect on the airline industry, leading to lower profits and higher passenger fares. Increased weight restrictions have previously been identified as potential impacts of climate change, but this study is the first to quantify the effect of higher temperatures on commercial aviation.

  2. Cascading effects of climate extremes on vertebrate fauna through changes to low-latitude tree flowering and fruiting phenology.

    PubMed

    Butt, Nathalie; Seabrook, Leonie; Maron, Martine; Law, Bradley S; Dawson, Terence P; Syktus, Jozef; McAlpine, Clive A

    2015-09-01

    Forest vertebrate fauna provide critical services, such as pollination and seed dispersal, which underpin functional and resilient ecosystems. In turn, many of these fauna are dependent on the flowering phenology of the plant species of such ecosystems. The impact of changes in climate, including climate extremes, on the interaction between these fauna and flora has not been identified or elucidated, yet influences on flowering phenology are already evident. These changes are well documented in the mid to high latitudes. However, there is emerging evidence that the flowering phenology, nectar/pollen production, and fruit production of long-lived trees in tropical and subtropical forests are also being impacted by changes in the frequency and severity of climate extremes. Here, we examine the implications of these changes for vertebrate fauna dependent on these resources. We review the literature to establish evidence for links between climate extremes and flowering phenology, elucidating the nature of relationships between different vertebrate taxa and flowering regimes. We combine this information with climate change projections to postulate about the likely impacts on nectar, pollen and fruit resource availability and the consequences for dependent vertebrate fauna. The most recent climate projections show that the frequency and intensity of climate extremes will increase during the 21st century. These changes are likely to significantly alter mass flowering and fruiting events in the tropics and subtropics, which are frequently cued by climate extremes, such as intensive rainfall events or rapid temperature shifts. We find that in these systems the abundance and duration of resource availability for vertebrate fauna is likely to fluctuate, and the time intervals between episodes of high resource availability to increase. The combined impact of these changes has the potential to result in cascading effects on ecosystems through changes in pollinator and seed

  3. Climate change impacts on extreme events in the United States: an uncertainty analysis

    EPA Science Inventory

    Extreme weather and climate events, such as heat waves, droughts and severe precipitation events, have substantial impacts on ecosystems and the economy. However, future climate simulations display large uncertainty in mean changes. As a result, the uncertainty in future changes ...

  4. Impacts of forced and unforced climate variability on extreme floods using a large climate ensemble

    NASA Astrophysics Data System (ADS)

    Martel, Jean-Luc; Brissette, François; Chen, Jie

    2016-04-01

    Frequency analysis has been widely used for the inference of flood magnitude and rainfall intensity required in engineering design. However, this inference is based on the concept of stationarity. How accurate is it when taking into account climate variability (i.e. both internal- and externally-forced variabilities)? Even in the absence of human-induced climate change, the short temporal horizon of the historical records renders this task extremely difficult to accomplish. To overcome this situation, large ensembles of simulations from a single climate model can be used to assess the impact of climate variability on precipitation and streamflow extremes. Thus, the objective of this project is to determine the reliability of return period estimates using the CanESM2 large ensemble. The spring flood annual maxima metric over snowmelt-dominated watersheds was selected to take into account the limits of global circulation models to properly simulate convective precipitation. The GR4J hydrological model coupled with the CemaNeige snow model was selected and calibrated using gridded observation datasets on snowmelt-dominated watersheds in Quebec, Canada. Using the hydrological model, streamflows were simulated using bias corrected precipitation and temperature data from the 50 members of CanESM2. Flood frequency analyses on the spring flood annual maxima were then computed using the Gumbel distribution with a 90% confidence interval. The 20-year return period estimates were then compared to assess the impact of natural climate variability over the 1971-2000 return period. To assess the impact of global warming, this methodology was then repeated for three time slices: reference period (1971-2000), near future (2036-2065) and far future (2071-2100). Over the reference period results indicate that the relative error between the return period estimates of two members can be up to 25%. Regarding the near future and far future periods, natural climate variability of extreme

  5. Climate extremes indices in the CMIP5 multimodel ensemble: Part 2. Future climate projections

    NASA Astrophysics Data System (ADS)

    Sillmann, J.; Kharin, V. V.; Zwiers, F. W.; Zhang, X.; Bronaugh, D.

    2013-03-01

    This study provides an overview of projected changes in climate extremes indices defined by the Expert Team on Climate Change Detection and Indices (ETCCDI). The temperature- and precipitation-based indices are computed with a consistent methodology for climate change simulations using different emission scenarios in the Coupled Model Intercomparison Project Phase 3 (CMIP3) and Phase 5 (CMIP5) multimodel ensembles. We analyze changes in the indices on global and regional scales over the 21st century relative to the reference period 1981-2000. In general, changes in indices based on daily minimum temperatures are found to be more pronounced than in indices based on daily maximum temperatures. Extreme precipitation generally increases faster than total wet-day precipitation. In regions, such as Australia, Central America, South Africa, and the Mediterranean, increases in consecutive dry days coincide with decreases in heavy precipitation days and maximum consecutive 5 day precipitation, which indicates future intensification of dry conditions. Particularly for the precipitation-based indices, there can be a wide disagreement about the sign of change between the models in some regions. Changes in temperature and precipitation indices are most pronounced under RCP8.5, with projected changes exceeding those discussed in previous studies based on SRES scenarios. The complete set of indices is made available via the ETCCDI indices archive to encourage further studies on the various aspects of changes in extremes.

  6. Riparian responses to extreme climate and land-use change scenarios.

    PubMed

    Fernandes, Maria Rosário; Segurado, Pedro; Jauch, Eduardo; Ferreira, Maria Teresa

    2016-11-01

    Climate change will induce alterations in the hydrological and landscape patterns with effects on riparian ecotones. In this study we assess the combined effect of an extreme climate and land-use change scenario on riparian woody structure and how this will translate into a future risk of riparian functionality loss. The study was conducted in the Tâmega catchment of the Douro basin. Boosted Regression Trees (BRTs) were used to model two riparian landscape indicators related with the degree of connectivity (Mean Width) and complexity (Area Weighted Mean Patch Fractal Dimension). Riparian data were extracted by planimetric analysis of high spatial-resolution Word Imagery Layer (ESRI). Hydrological, climatic and land-use variables were obtained from available datasets and generated with process-based modeling using current climate data (2008-2014), while also considering the high-end RCP8.5 climate-change and "Icarus" socio-economic scenarios for the 2046-2065 time slice. Our results show that hydrological and land-use changes strongly influence future projections of riparian connectivity and complexity, albeit to diverse degrees and with differing effects. A harsh reduction in average flows may impair riparian zones while an increase in extreme rain events may benefit connectivity by promoting hydrologic dynamics with the surrounding floodplains. The expected increase in broad-leaved woodlands and mixed forests may enhance the riparian galleries by reducing the agricultural pressure on the area in the vicinity of the river. According to our results, 63% of river segments in the Tâmega basin exhibited a moderate risk of functionality loss, 16% a high risk, and 21% no risk. Weaknesses and strengths of the method are highlighted and results are discussed based on a resilience perspective with regard to riparian ecosystems. PMID:27341115

  7. Riparian responses to extreme climate and land-use change scenarios.

    PubMed

    Fernandes, Maria Rosário; Segurado, Pedro; Jauch, Eduardo; Ferreira, Maria Teresa

    2016-11-01

    Climate change will induce alterations in the hydrological and landscape patterns with effects on riparian ecotones. In this study we assess the combined effect of an extreme climate and land-use change scenario on riparian woody structure and how this will translate into a future risk of riparian functionality loss. The study was conducted in the Tâmega catchment of the Douro basin. Boosted Regression Trees (BRTs) were used to model two riparian landscape indicators related with the degree of connectivity (Mean Width) and complexity (Area Weighted Mean Patch Fractal Dimension). Riparian data were extracted by planimetric analysis of high spatial-resolution Word Imagery Layer (ESRI). Hydrological, climatic and land-use variables were obtained from available datasets and generated with process-based modeling using current climate data (2008-2014), while also considering the high-end RCP8.5 climate-change and "Icarus" socio-economic scenarios for the 2046-2065 time slice. Our results show that hydrological and land-use changes strongly influence future projections of riparian connectivity and complexity, albeit to diverse degrees and with differing effects. A harsh reduction in average flows may impair riparian zones while an increase in extreme rain events may benefit connectivity by promoting hydrologic dynamics with the surrounding floodplains. The expected increase in broad-leaved woodlands and mixed forests may enhance the riparian galleries by reducing the agricultural pressure on the area in the vicinity of the river. According to our results, 63% of river segments in the Tâmega basin exhibited a moderate risk of functionality loss, 16% a high risk, and 21% no risk. Weaknesses and strengths of the method are highlighted and results are discussed based on a resilience perspective with regard to riparian ecosystems.

  8. Carbon cycle extremes during the 21st century in CMIP5 models: Future evolution and attribution to climatic drivers

    NASA Astrophysics Data System (ADS)

    Zscheischler, Jakob; Reichstein, Markus; von Buttlar, Jannis; Mu, Mingquan; Randerson, James T.; Mahecha, Miguel D.

    2014-12-01

    Climate extremes such as droughts and heat waves affect terrestrial ecosystems and may alter local carbon budgets. However, it still remains uncertain to what degree extreme impacts in the carbon cycle influence the carbon cycle-climate feedback both today and the near future. Here we analyze spatiotemporally contiguous negative extreme anomalies in gross primary production (GPP) and net ecosystem production (NEP) in model output of the Coupled Model Intercomparison Project Phase 5 (CMIP5) ensemble and investigate their future development and attribution to climatic drivers. We find that relative to the overall increase in global carbon uptake, negative extremes in GPP and NEP lose importance toward the end of the 21st century. This effect can be related to elevated CO2 concentrations and higher amounts of available water at the global scale, partially mitigating the impacts of droughts and heat waves, respectively. Overall, based on CMIP5 models, we hypothesize that terrestrial ecosystems might be more resilient against future climate extremes than previously thought. Future work will have to further scrutinize these results considering that various biological and biogeochemical feedbacks are not yet integrated within Earth system models.

  9. The spatial distribution of extreme climate events, another climate inequity for the world’s most vulnerable people

    NASA Astrophysics Data System (ADS)

    Green, Donna

    2016-09-01

    Does the climate change signal emerge equally from internal climate variability across the globe? If not, are there particular locations where temperature extremes might disproportionately affect specific populations? The letter by Harrington et al (2016 Environ. Res. Lett. 11 055007) argues that people living in low latitude countries, which contain the majority of the world’s poorest people, are—and will continue to be—disproportionately affected by increases in temperature extremes. Due to differences in expertise of climate scientists, and climate impact and adaptation scientists, few climate extreme event analyses are spatially disaggregated and linked to local populations’ socio-economic characteristics. The research presented in this letter begins to bridge this gap by providing evidence of inequitable spatial impacts from climate extremes on the world’s poorest people.

  10. Adaptive thermoregulation in endotherms may alter responses to climate change.

    PubMed

    Boyles, Justin G; Seebacher, Frank; Smit, Ben; McKechnie, Andrew E

    2011-11-01

    Climate change is one of the major issues facing natural populations and thus a focus of recent research has been to predict the responses of organisms to these changes. Models are becoming more complex and now commonly include physiological traits of the organisms of interest. However, endothermic species have received less attention than have ectotherms in these mechanistic models. Further, it is not clear whether responses of endotherms to climate change are modified by variation in thermoregulatory characteristics associated with phenotypic plasticity and/or adaptation to past selective pressures. Here, we review the empirical data on thermal adaptation and acclimatization in endotherms and discuss how those factors may be important in models of responses to climate change. We begin with a discussion of why thermoregulation and thermal sensitivity at high body temperatures should be co-adapted. Importantly, we show that there is, in fact, considerable variation in the ability of endotherms to tolerate high body temperatures and/or high environmental temperatures, but a better understanding of this variation will likely be critical for predicting responses to future climatic scenarios. Next, we discuss why variation in thermoregulatory characteristics should be considered when modeling the effects of climate change on heterothermic endotherms. Finally, we review some biophysical and biochemical factors that will limit adaptation and acclimation in endotherms. We consider both long-term, directional climate change and short-term (but increasingly common) anomalies in climate such as extreme heat waves and we suggest areas of important future research relating to both our basic understanding of endothermic thermoregulation and the responses of endotherms to climate change.

  11. Evaluation of multiple regional climate models for summer climate extremes over East Asia

    NASA Astrophysics Data System (ADS)

    Park, Changyong; Min, Seung-Ki; Lee, Donghyun; Cha, Dong-Hyun; Suh, Myoung-Seok; Kang, Hyun-Suk; Hong, Song-You; Lee, Dong-Kyou; Baek, Hee-Jeong; Boo, Kyung-On; Kwon, Won-Tae

    2016-04-01

    In this study, five regional climate models (RCMs) participating in the CORDEX-East Asia project (HadGEM3-RA, RegCM4, SNU-MM5, SNU-WRF, and YSU-RSM) are evaluated in terms of their performances in simulating the climatology of summer extremes in East Asia. Seasonal maxima of daily mean temperature and precipitation are analyzed using the generalized extreme value method. RCMs show systematic bias patterns in both seasonal means and extremes. A cold bias is located along the coast, whereas a warm bias occurs in northern China. Overall, wet bias occurs in East Asia, but with a substantial dry bias centered in South Korea. This dry bias appears to be related to the colder ocean surface around South Korea, positioning the monsoonal front further south compared to observations. Taylor diagram analyses reveal that the models simulate temperature means more accurately compared to extremes because of the higher spatial correlation, whereas precipitation extremes are simulated better than their means because of the higher spatial variability. The latter implies that extreme rainfall events can be captured more accurately by RCMs compared to the driving GCM despite poorer simulation of mean rainfall. Inter-RCM analysis indicates a close relationship between the means and extremes in terms of model skills, but it does not show a clear relationship between temperature and precipitation. Sub-regional analysis largely supports the mean-extreme skill relationship. Analyses of frequency and intensity distributions of daily data for three selected sub-regions suggest that overall shifts of temperature distribution and biases in moderate-heavy precipitations contribute importantly to the seasonal mean biases.

  12. The potential impacts of climate variability and change on health impacts of extreme weather events in the United States.

    PubMed Central

    Greenough, G; McGeehin, M; Bernard, S M; Trtanj, J; Riad, J; Engelberg, D

    2001-01-01

    Extreme weather events such as precipitation extremes and severe storms cause hundreds of deaths and injuries annually in the United States. Climate change may alter the frequency, timing, intensity, and duration of these events. Increases in heavy precipitation have occurred over the past century. Future climate scenarios show likely increases in the frequency of extreme precipitation events, including precipitation during hurricanes, raising the risk of floods. Frequencies of tornadoes and hurricanes cannot reliably be projected. Injury and death are the direct health impacts most often associated with natural disasters. Secondary effects, mediated by changes in ecologic systems and public health infrastructure, also occur. The health impacts of extreme weather events hinge on the vulnerabilities and recovery capacities of the natural environment and the local population. Relevant variables include building codes, warning systems, disaster policies, evacuation plans, and relief efforts. There are many federal, state, and local government agencies and nongovernmental organizations involved in planning for and responding to natural disasters in the United States. Future research on health impacts of extreme weather events should focus on improving climate models to project any trends in regional extreme events and as a result improve public health preparedness and mitigation. Epidemiologic studies of health effects beyond the direct impacts of disaster will provide a more accurate measure of the full health impacts and will assist in planning and resource allocation. PMID:11359686

  13. The potential impacts of climate variability and change on health impacts of extreme weather events in the United States.

    PubMed

    Greenough, G; McGeehin, M; Bernard, S M; Trtanj, J; Riad, J; Engelberg, D

    2001-05-01

    Extreme weather events such as precipitation extremes and severe storms cause hundreds of deaths and injuries annually in the United States. Climate change may alter the frequency, timing, intensity, and duration of these events. Increases in heavy precipitation have occurred over the past century. Future climate scenarios show likely increases in the frequency of extreme precipitation events, including precipitation during hurricanes, raising the risk of floods. Frequencies of tornadoes and hurricanes cannot reliably be projected. Injury and death are the direct health impacts most often associated with natural disasters. Secondary effects, mediated by changes in ecologic systems and public health infrastructure, also occur. The health impacts of extreme weather events hinge on the vulnerabilities and recovery capacities of the natural environment and the local population. Relevant variables include building codes, warning systems, disaster policies, evacuation plans, and relief efforts. There are many federal, state, and local government agencies and nongovernmental organizations involved in planning for and responding to natural disasters in the United States. Future research on health impacts of extreme weather events should focus on improving climate models to project any trends in regional extreme events and as a result improve public health preparedness and mitigation. Epidemiologic studies of health effects beyond the direct impacts of disaster will provide a more accurate measure of the full health impacts and will assist in planning and resource allocation.

  14. (When and where) Do extreme climate events trigger extreme ecosystem responses? - Development and initial results of a holistic analysis framework

    NASA Astrophysics Data System (ADS)

    Hauber, Eva K.; Donner, Reik V.

    2015-04-01

    In the context of ongoing climate change, extremes are likely to increase in magnitude and frequency. One of the most important consequences of these changes is that the associated ecological risks and impacts are potentially rising as well. In order to better anticipate and understand these impacts, it therefore becomes more and more crucial to understand the general connection between climate extremes and the response and functionality of ecosystems. Among other region of the world, Europe presents an excellent test case for studies concerning the interaction between climate and biosphere, since it lies in the transition region between cold polar and warm tropical air masses and thus covers a great variety of different climatic zones and associated terrestrial ecosystems. The large temperature differences across the continent make this region particularly interesting for investigating the effects of climate change on biosphere-climate interactions. However, previously used methods for defining an extreme event typically disregard the necessity of taking seasonality as well as seasonal variance appropriately into account. Furthermore, most studies have focused on the impacts of individual extreme events instead of considering a whole inventory of extremes with their respective spatio-temporal extents. In order to overcome the aforementioned research gaps, this work introduces a new approach to studying climate-biosphere interactions associated with extreme events, which comprises three consecutive steps: (1) Since Europe exhibits climatic conditions characterized by marked seasonality, a novel method is developed to define extreme events taking into account the seasonality in all quantiles of the probability distribution of the respective variable of interest. This is achieved by considering kernel density estimates individually for each observation date during the year, including the properly weighted information from adjacent dates. By this procedure, we obtain

  15. Increasing climate extremes under global warming - What is the driving force?

    NASA Astrophysics Data System (ADS)

    Yoon, J.; Wang, S. Y.; Gillies, R. R.; Hipps, L.; Kravitz, B.; Rasch, P. J.

    2015-12-01

    More climate extreme events have occurred in recent years, including the continual development of extreme drought in California, the severe cold winters in the eastern U.S. since 2014, 2015 Washington drought, and excessive wildfire events over Alaska in 2015. These have been casually attributed to global warming. However, a need for further understanding of mechanisms responsible for climate extremes is growing. In this presentation, we'll use sets of climate model simulation that designed to identify the role of the oceanic feedback in increasing climate extremes under global warming. One is with a fully coupled climate model forced by 1% ramping CO2, and the other is with an atmosphere only model forced by the same CO2 forcing. By contrasting these two, an importance of the oceanic feedback in increasing climate extremes under global warming can be diagnosed.

  16. Resolution dependence of simulated extreme wave climate in the North Atlantic in a changing climate.

    NASA Astrophysics Data System (ADS)

    Timmermans, B.; Stone, D. A.; Wehner, M. F.; Krishnan, H.

    2015-12-01

    Recent studies have investigated how regional and global wave climate may change in a warmer world. The approach is often to project wave climate by using output from atmospheric circulation models, either as input to statistical downscaling methods that determine the resulting waves, or as forcing for numerical wind-wave models. An important influence on the wave climate is the frequency and intensity of tropical cyclones, but to date, many atmospheric models have been run at resolutions too low (~1.0 degree) to accurately reproduce such phenomenon, which in turn has lead to poor predictions of waves in affected regions. Tropical cyclones therefore remain an important source of uncertainty in projections of wave climate. However, output from recent high resolution simulations (~0.25 degree) of atmospheric circulation shows considerable improvement in the model's ability to simulate tropical cyclones. In order to investigate the importance of this issue on projections of waves, we present results of the analysis of wave climate in the North Atlantic, by forcing the global wave model, Wavewatch III, with both low and high resolution output from the Community Atmosphere Model 5.1, under atmospheric conditions of both the early 1990s, and conditions with a 2 degree increase in sea surface temperature and increased atmospheric CO2. Extremes of the wave climatology in the North Atlantic are examined and the consequences for the U.S. eastern seaboard are discussed.

  17. Pilot system on extreme climate monitoring and early warning for long range forecast in Korea

    NASA Astrophysics Data System (ADS)

    Cho, K.; Park, B. K.; E-hyung, P.; Gong, Y.; Kim, H. K.; Park, S.; Min, S. K.; Yoo, H. D.

    2015-12-01

    Recently, extreme weather/climate events such as heat waves, flooding/droughts etc. have been increasing in frequency and intensity under climate change over the world. Also, they can have substantial impacts on ecosystem and human society (agriculture, health, and economy) of the affected regions. According to future projections of climate, extreme weather and climate events in Korea are expected to occure more frequently with stronger intensity over the 21st century. For the better long range forecast, it is also fundamentally ruquired to develop a supporting system in terms of extreme weather and climate events including forequency and trend. In this context, the KMA (Korea Meteorological Administration) has recently initiated a development of the extreme climate monintoring and early warning system for long range forecast, which consists of three sub-system components; (1) Real-time climate monitoring system, (2) Ensemble prediction system, and (3) Mechanism analysis and display system for climate extremes. As a first step, a pilot system has been designed focusing on temperature extremes such heat waves and cold snaps using daily, monthly and seasonal observations and model prediction output on the global, regional and national levels. In parallel, the skills of the KMA long range prediction system are being evaluated comprehensively for weather and climate extremes, for which varous case studies are conducted to better understand the observed variations of extrem climates and responsible mechanisms and also to assess predictability of the ensemble prediction system for extremes. Details in the KMA extreme climate monitoring and early warning system will be intorduced and some preliminary results will be discussed for heat/cold waves in Korea.

  18. The Climatology of Climate Extremes in the World's Major Growing Regions

    NASA Astrophysics Data System (ADS)

    Troy, T.; Zhu, X.

    2015-12-01

    A stable food supply is increasingly important as global populations grow and climate variability and extremes affect crop yields. It is therefore critical to quantify the occurrence of extremes in major growing regions globally to understand the vulnerability of the global food supply to climate. First, we grid the GHCN historical climate data and evaluate the effect of gridding on estimation of agriculturally relevant climate extremes, such as heat waves, consecutive dry days, and precipitation intensity. We find that the differences between gridded indices and the raw station indices are small, mostly less than 10%. We then evaluate the climatology of climate extremes and the probability of concurrent extremes, both within one growing region and across multiple regions globally. We find that the correlation of two precipitation or temperature related indices are quite strong, such that the probability of another extreme occurring increases given the occurrence of one extreme. These results provide estimations of the global food supply's vulnerability to climate variability and extremes, which is critical for planning in the coming decades with projections of more frequent and more intense climate extremes.

  19. 21st Century Changes in Precipitation Extremes Over the United States: Can Climate Analogues Help or Hinder?

    NASA Astrophysics Data System (ADS)

    Gao, X.; Schlosser, C. A.

    2013-12-01

    Global warming is expected to alter the frequency and/or magnitude of extreme precipitation events. Such changes could have substantial ecological, economic, and sociological consequences. However, climate models in general do not correctly reproduce the frequency and intensity distribution of precipitation, especially at the regional scale. In this study, gridded data from a dense network of surface precipitation gauges and a global atmospheric analysis at a coarser scale are combined to develop a diagnostic framework for the large-scale meteorological conditions (i.e. flow features, moisture supply) that dominate during extreme precipitation. Such diagnostic framework is first evaluated with the late 20th century simulations from an ensemble of climate models participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5), and is found to produce more consistent (and less uncertain) total and interannaul number of extreme days with the observations than the model-based precipitation over the south-central United States and the Western United States examined in this study. The framework is then applied to the CMIP5 multi-model projections for two radiative forcing scenarios (Representative Concentration Pathways 4.5 and 8.5) to assess the potential future changes in the probability of precipitation extremes over the same study regions. We further analyze the accompanying circulation features and their changes that may be responsible for shifts in extreme precipitation in response to changed climate. The results from this study may guide hazardous weather watches and help society develop adaptive strategies for preventing catastrophic losses.

  20. Graceful Failure, Engineering, and Planning for Extremes: The Engineering for Climate Extremes Partnership (ECEP)

    NASA Astrophysics Data System (ADS)

    Bruyere, C. L.; Tye, M. R.; Holland, G. J.; Done, J.

    2015-12-01

    Graceful failure acknowledges that all systems will fail at some level and incorporates the potential for failure as a key component of engineering design, community planning, and the associated research and development. This is a fundamental component of the ECEP, an interdisciplinary partnership bringing together scientific, engineering, cultural, business and government expertise to develop robust, well-communicated predictions and advice on the impacts of weather and climate extremes in support of decision-making. A feature of the partnership is the manner in which basic and applied research and development is conducted in direct collaboration with the end user. A major ECEP focus is the Global Risk and Resilience Toolbox (GRRT) that is aimed at developing public-domain, risk-modeling and response data and planning system in support of engineering design, and community planning and adaptation activities. In this presentation I will outline the overall ECEP and GRIP activities, and expand on the 'graceful failure' concept. Specific examples for direct assessment and prediction of hurricane impacts and damage potential will be included.

  1. Climate impacts on extreme energy consumption of different types of buildings.

    PubMed

    Li, Mingcai; Shi, Jun; Guo, Jun; Cao, Jingfu; Niu, Jide; Xiong, Mingming

    2015-01-01

    Exploring changes of building energy consumption and its relationships with climate can provide basis for energy-saving and carbon emission reduction. Heating and cooling energy consumption of different types of buildings during 1981-2010 in Tianjin city, was simulated by using TRNSYS software. Daily or hourly extreme energy consumption was determined by percentile methods, and the climate impact on extreme energy consumption was analyzed. The results showed that days of extreme heating consumption showed apparent decrease during the recent 30 years for residential and large venue buildings, whereas days of extreme cooling consumption increased in large venue building. No significant variations were found for the days of extreme energy consumption for commercial building, although a decreasing trend in extreme heating energy consumption. Daily extreme energy consumption for large venue building had no relationship with climate parameters, whereas extreme energy consumption for commercial and residential buildings was related to various climate parameters. Further multiple regression analysis suggested heating energy consumption for commercial building was affected by maximum temperature, dry bulb temperature, solar radiation and minimum temperature, which together can explain 71.5 % of the variation of the daily extreme heating energy consumption. The daily extreme cooling energy consumption for commercial building was only related to the wet bulb temperature (R2= 0.382). The daily extreme heating energy consumption for residential building was affected by 4 climate parameters, but the dry bulb temperature had the main impact. The impacts of climate on hourly extreme heating energy consumption has a 1-3 hour delay in all three types of buildings, but no delay was found in the impacts of climate on hourly extreme cooling energy consumption for the selected buildings.

  2. Climate impacts on extreme energy consumption of different types of buildings.

    PubMed

    Li, Mingcai; Shi, Jun; Guo, Jun; Cao, Jingfu; Niu, Jide; Xiong, Mingming

    2015-01-01

    Exploring changes of building energy consumption and its relationships with climate can provide basis for energy-saving and carbon emission reduction. Heating and cooling energy consumption of different types of buildings during 1981-2010 in Tianjin city, was simulated by using TRNSYS software. Daily or hourly extreme energy consumption was determined by percentile methods, and the climate impact on extreme energy consumption was analyzed. The results showed that days of extreme heating consumption showed apparent decrease during the recent 30 years for residential and large venue buildings, whereas days of extreme cooling consumption increased in large venue building. No significant variations were found for the days of extreme energy consumption for commercial building, although a decreasing trend in extreme heating energy consumption. Daily extreme energy consumption for large venue building had no relationship with climate parameters, whereas extreme energy consumption for commercial and residential buildings was related to various climate parameters. Further multiple regression analysis suggested heating energy consumption for commercial building was affected by maximum temperature, dry bulb temperature, solar radiation and minimum temperature, which together can explain 71.5 % of the variation of the daily extreme heating energy consumption. The daily extreme cooling energy consumption for commercial building was only related to the wet bulb temperature (R2= 0.382). The daily extreme heating energy consumption for residential building was affected by 4 climate parameters, but the dry bulb temperature had the main impact. The impacts of climate on hourly extreme heating energy consumption has a 1-3 hour delay in all three types of buildings, but no delay was found in the impacts of climate on hourly extreme cooling energy consumption for the selected buildings. PMID:25923205

  3. Climate extremes in the Pacific: improving seasonal prediction of tropical cyclones and extreme ocean temperatures to improve resilience

    NASA Astrophysics Data System (ADS)

    Kuleshov, Y.; Jones, D.; Spillman, C. M.

    2012-04-01

    Climate change and climate extremes have a major impact on Australia and Pacific Island countries. Of particular concern are tropical cyclones and extreme ocean temperatures, the first being the most destructive events for terrestrial systems, while the latter has the potential to devastate ocean ecosystems through coral bleaching. As a practical response to climate change, under the Pacific-Australia Climate Change Science and Adaptation Planning program (PACCSAP), we are developing enhanced web-based information tools for providing seasonal forecasts for climatic extremes in the Western Pacific. Tropical cyclones are the most destructive weather systems that impact on coastal areas. Interannual variability in the intensity and distribution of tropical cyclones is large, and presently greater than any trends that are ascribable to climate change. In the warming environment, predicting tropical cyclone occurrence based on historical relationships, with predictors such as sea surface temperatures (SSTs) now frequently lying outside of the range of past variability meaning that it is not possible to find historical analogues for the seasonal conditions often faced by Pacific countries. Elevated SSTs are the primary trigger for mass coral bleaching events, which can lead to widespread damage and mortality on reef systems. Degraded coral reefs present many problems, including long-term loss of tourism and potential loss or degradation of fisheries. The monitoring and prediction of thermal stress events enables the support of a range of adaptive and management activities that could improve reef resilience to extreme conditions. Using the climate model POAMA (Predictive Ocean-Atmosphere Model for Australia), we aim to improve accuracy of seasonal forecasts of tropical cyclone activity and extreme SSTs for the regions of Western Pacific. Improved knowledge of extreme climatic events, with the assistance of tailored forecast tools, will help enhance the resilience and

  4. Climate variability and extremes, interacting with nitrogen storage, amplify eutrophication risk

    NASA Astrophysics Data System (ADS)

    Lee, Minjin; Shevliakova, Elena; Malyshev, Sergey; Milly, P. C. D.; Jaffé, Peter R.

    2016-07-01

    Despite 30 years of basin-wide nutrient-reduction efforts, severe hypoxia continues to be observed in the Chesapeake Bay. Here we demonstrate the critical influence of climate variability, interacting with accumulated nitrogen (N) over multidecades, on Susquehanna River dissolved nitrogen (DN) loads, known precursors of the hypoxia in the Bay. We used the process model LM3-TAN (Terrestrial and Aquatic Nitrogen), which is capable of capturing both seasonal and decadal-to-century changes in vegetation-soil-river N storage, and produced nine scenarios of DN-load distributions under different short-term scenarios of climate variability and extremes. We illustrate that after 1 to 3 yearlong dry spells, the likelihood of exceeding a threshold DN load (56 kt yr-1) increases by 40 to 65% due to flushing of N accumulated throughout the dry spells and altered microbial processes. Our analyses suggest that possible future increases in climate variability/extremes—specifically, high precipitation occurring after multiyear dry spells—could likely lead to high DN-load anomalies and hypoxia.

  5. Climate extremes can drive biological assemblages to early successional stages compared to several mild disturbances.

    PubMed

    Sanz-Lázaro, Carlos

    2016-01-01

    Extreme climatic events have a major role in the structuring of biological communities, and their occurrence is expected to increase due to climate change. Here I use a manipulative approach to test the effects of extreme storm events on rocky mid-shore assemblages. This study shows that an extreme storm can cause more negative effects than several mild storms, primarily by bringing the biological assemblages towards early stages of succession. This finding contrasts with the effects of clustering of climatic events due to climate change, which are expected to mitigate its ecological impacts. Thus, the ecological consequences of climatic events that are influenced by climate change may have contrasting effects depending on the features that are considered. These results have relevant implications in the forecasting of the ecological consequences of climate change and should be considered when designing measures to mitigate its effects.

  6. Climate extremes can drive biological assemblages to early successional stages compared to several mild disturbances.

    PubMed

    Sanz-Lázaro, Carlos

    2016-01-01

    Extreme climatic events have a major role in the structuring of biological communities, and their occurrence is expected to increase due to climate change. Here I use a manipulative approach to test the effects of extreme storm events on rocky mid-shore assemblages. This study shows that an extreme storm can cause more negative effects than several mild storms, primarily by bringing the biological assemblages towards early stages of succession. This finding contrasts with the effects of clustering of climatic events due to climate change, which are expected to mitigate its ecological impacts. Thus, the ecological consequences of climatic events that are influenced by climate change may have contrasting effects depending on the features that are considered. These results have relevant implications in the forecasting of the ecological consequences of climate change and should be considered when designing measures to mitigate its effects. PMID:27527612

  7. Climate extremes can drive biological assemblages to early successional stages compared to several mild disturbances

    PubMed Central

    Sanz-Lázaro, Carlos

    2016-01-01

    Extreme climatic events have a major role in the structuring of biological communities, and their occurrence is expected to increase due to climate change. Here I use a manipulative approach to test the effects of extreme storm events on rocky mid-shore assemblages. This study shows that an extreme storm can cause more negative effects than several mild storms, primarily by bringing the biological assemblages towards early stages of succession. This finding contrasts with the effects of clustering of climatic events due to climate change, which are expected to mitigate its ecological impacts. Thus, the ecological consequences of climatic events that are influenced by climate change may have contrasting effects depending on the features that are considered. These results have relevant implications in the forecasting of the ecological consequences of climate change and should be considered when designing measures to mitigate its effects. PMID:27527612

  8. Perturbing a Stochastic Weather Generator with Different Climate Change Signals to Assess Extreme Precipitation under Influence of Climate Change at Urban Scales

    NASA Astrophysics Data System (ADS)

    Sørup, H. J.; Christensen, O. B.; Arnbjerg-Nielsen, K.; Mikkelsen, P. S.

    2013-12-01

    In recent years, urban flooding has occurred in Denmark due to very short lived local extreme precipitation events. Several of these floods have been among the most severe experienced to date. Climate change is expected to alter the frequency of extreme precipitation events causing floods, but in general climate models are poor in representing extreme precipitation events. The current study demonstrates how the Spatio-Temporal Neyman-Scott Rectangular Pulses weather generator can be applied at urban scale and how it can be used for statistical downscaling by perturbation with a climate change signal. The weather generator is fitted to data from a dense network of high resolution tipping bucket rain gauges in and around Copenhagen. The weather generator is validated by its ability to reproduce realistic extreme precipitation statistics. The model reproduces intensity-duration-frequency statistics down to the one-hour time scale satisfactorily. It furthermore reproduces realistic spatial correlation patterns at the extreme rain event level when output is sampled on a 2-km grid. For downscaling, perturbation with a climate change signal obtained from four different regional climate model simulations has been analyzed. The analyzed data sets originates from two regional climate model (RCM) runs from the European ENSEMBLES project (RACMO/ECHAM and HIRHAM/ECHAM, A1B scenario and 25 km spatial scale) and two RCM runs just for southern Scandinavia performed by the Danish Meteorological Institute (both HIRHAM/EC-EARTH, rcp 4.5 and rcp 8.5 scenarios and 8 km spatial scale). The data sets are all at one-hour time resolution. All data sets result in markedly different perturbation schemes for the weather generator. The downscaled time series are analyzed in accordance to the validation procedure and change factors for the extremes are derived as a function of return period. Despite different perturbation schemes both A1B scenario model runs and the rcp 4.5 scenario model run

  9. Modeling Shasta Dam operations to regulate temperatures for Chinook salmon under extreme climate and climate change

    NASA Astrophysics Data System (ADS)

    Dai, A.; Saito, L.; Sapin, J. R.; Rajagopalan, B.; Hanna, R. B.; Kauneckis, D. L.

    2014-12-01

    Chinook salmon populations have declined significantly after the construction of Shasta Dam on the Sacramento River in 1945 prevented them from spawning in the cold waters upstream. In 1994, the winter-run Chinook were listed under the Endangered Species Act and 3 years later the US Bureau of Reclamation began operating a temperature control device (TCD) on the dam that allows for selective withdrawal for downstream temperature control to promote salmon spawning while also maximizing power generation. However, dam operators are responsible to other interests that depend on the reservoir for water such as agriculture, municipalities, industry, and recreation. An increase in temperatures due to climate change may place additional strain on the ability of dam operations to maintain spawning habitat for salmon downstream of the dam. We examined the capability of Shasta Dam to regulate downstream temperatures under extreme climates and climate change by using stochastically generated streamflow, stream temperature, and weather inputs with a two-dimensional CE-QUAL-W2 model under several operational options. Operation performance was evaluated using degree days and cold pool volume (volume of water below a temperature threshold). Model results indicated that a generalized operations release schedule, in which release elevations varied over the year to match downstream temperature targets, performed best overall in meeting temperature targets while preserving cold pool volume. Releasing all water out the bottom throughout the year tended to meet temperature targets at the expense of depleting the cold pool, and releasing all water out uppermost gates preserved the cold pool, but released water that was too warm during the critical spawning period. With higher air temperatures due to climate change, both degree day and cold pool volume metrics were worse than baseline conditions, which suggests that Chinook salmon may be more negatively affected under climate change.

  10. Estimating changes in temperature extremes from millennial-scale climate simulations using generalized extreme value (GEV) distributions

    NASA Astrophysics Data System (ADS)

    Huang, Whitney K.; Stein, Michael L.; McInerney, David J.; Sun, Shanshan; Moyer, Elisabeth J.

    2016-07-01

    Changes in extreme weather may produce some of the largest societal impacts of anthropogenic climate change. However, it is intrinsically difficult to estimate changes in extreme events from the short observational record. In this work we use millennial runs from the Community Climate System Model version 3 (CCSM3) in equilibrated pre-industrial and possible future (700 and 1400 ppm CO2) conditions to examine both how extremes change in this model and how well these changes can be estimated as a function of run length. We estimate changes to distributions of future temperature extremes (annual minima and annual maxima) in the contiguous United States by fitting generalized extreme value (GEV) distributions. Using 1000-year pre-industrial and future time series, we show that warm extremes largely change in accordance with mean shifts in the distribution of summertime temperatures. Cold extremes warm more than mean shifts in the distribution of wintertime temperatures, but changes in GEV location parameters are generally well explained by the combination of mean shifts and reduced wintertime temperature variability. For cold extremes at inland locations, return levels at long recurrence intervals show additional effects related to changes in the spread and shape of GEV distributions. We then examine uncertainties that result from using shorter model runs. In theory, the GEV distribution can allow prediction of infrequent events using time series shorter than the recurrence interval of those events. To investigate how well this approach works in practice, we estimate 20-, 50-, and 100-year extreme events using segments of varying lengths. We find that even using GEV distributions, time series of comparable or shorter length than the return period of interest can lead to very poor estimates. These results suggest caution when attempting to use short observational time series or model runs to infer infrequent extremes.

  11. Managing the Risks of Extreme Events and Disasters in a Changing Climate: Lessons for Adaptation to Climate Change (Invited)

    NASA Astrophysics Data System (ADS)

    Mastrandrea, M.; Field, C. B.; Mach, K. J.; Barros, V.

    2013-12-01

    The IPCC Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation, published in 2012, integrates expertise in climate science, disaster risk reduction, and adaptation to inform discussions on how to reduce and manage the risks of extreme events and disasters in a changing climate. Impacts and the risks of disasters are determined by the interaction of the physical characteristics of weather and climate events with the vulnerability of exposed human society and ecosystems. The Special Report evaluates the factors that make people and infrastructure vulnerable to extreme events, trends in disaster losses, recent and future changes in the relationship between climate change and extremes, and experience with a wide range of options used by institutions, organizations, and communities to reduce exposure and vulnerability, and improve resilience, to climate extremes. Actions ranging from incremental improvements in governance and technology to more transformational changes are assessed. The Special Report provides a knowledge base that is also relevant to the broader context of managing the risks of climate change through mitigation, adaptation, and other responses, assessed in the IPCC's Fifth Assessment Report (AR5), to be completed in 2014. These themes include managing risks through an iterative process involving learning about risks and the effectiveness of responses, employing a portfolio of actions tailored to local circumstances but with links from local to global scales, and considering additional benefits of actions such as improving livelihoods and well-being. The Working Group II contribution to the AR5 also examines the ways that extreme events and their impacts contribute to understanding of vulnerabilities and adaptation deficits in the context of climate change, the extent to which impacts of climate change are experienced through changes in the frequency and severity of extremes as opposed to mean changes

  12. Responses of greenhouse gas fluxes to climate extremes in a semiarid grassland

    NASA Astrophysics Data System (ADS)

    Li, Linfeng; Fan, Wenyu; Kang, Xiaoming; Wang, Yanfen; Cui, Xiaoyong; Xu, Chengyuan; Griffin, Kevin L.; Hao, Yanbin

    2016-10-01

    Climate extremes are expected to increase in frequency and intensity as a consequence of anthropogenic climate change attributed to the rise of atmospheric concentrations of greenhouse gases (GHGs). However, studies on the impacts of climate extremes on terrestrial ecosystems are limited. Here, we experimentally imposed extreme drought and a heat wave (∼60-year recurrence) to investigate their effects on GHGs fluxes of a semiarid grassland in China. We estimated a 16% and 38% percent reduction in net ecosystem CO2 uptake caused by the heat wave and drought respectively, but via different mechanisms. Drought reduced gross ecosystem productively (GEP) and to a lower extent ecosystem respiration (ER). By contrast, the simulated heat wave suppressed only GEP while ER remained stable. The climate extremes also created a legacy effect on GEP and NEE lasting until the end of the growing season, whereas ER recovered immediately. Although CH4 and N2O fluxes were unaffected by the heat wave, drought promoted CH4 uptake and suppressed N2O emission during the treatment period. The effect of drought on GHGs fluxes generally overwhelmed that of the heat wave treatment, and there were no interactive effects of these two types of climate extremes. Our results showed that responses of ecosystem GHGs exchange to climate extremes are strongly regulated by soil moisture status. In conclusion, future amplification of climate extremes could decrease the sink for GHGs, especially CO2, in this semiarid grasslands.

  13. Interactive effects of elevation, species richness and extreme climatic events on plant-pollinator networks.

    PubMed

    Hoiss, Bernhard; Krauss, Jochen; Steffan-Dewenter, Ingolf

    2015-11-01

    Plant-pollinator interactions are essential for the functioning of terrestrial ecosystems, but are increasingly affected by global change. The risks to such mutualistic interactions from increasing temperature and more frequent extreme climatic events such as drought or advanced snow melt are assumed to depend on network specialization, species richness, local climate and associated parameters such as the amplitude of extreme events. Even though elevational gradients provide valuable model systems for climate change and are accompanied by changes in species richness, responses of plant-pollinator networks to climatic extreme events under different environmental and biotic conditions are currently unknown. Here, we show that elevational climatic gradients, species richness and experimentally simulated extreme events interactively change the structure of mutualistic networks in alpine grasslands. We found that the degree of specialization in plant-pollinator networks (H2') decreased with elevation. Nonetheless, network specialization increased after advanced snow melt at high elevations, whereas changes in network specialization after drought were most pronounced at sites with low species richness. Thus, changes in network specialization after extreme climatic events depended on climatic context and were buffered by high species richness. In our experiment, only generalized plant-pollinator networks changed in their degree of specialization after climatic extreme events. This indicates that contrary to our assumptions, network generalization may not always foster stability of mutualistic interaction networks.

  14. Changing climate cues differentially alter zooplankton dormancy dynamics across latitudes.

    PubMed

    Jones, Natalie T; Gilbert, Benjamin

    2016-03-01

    In seasonal climates, dormancy is a common strategy that structures biodiversity and is necessary for the persistence of many species. Climate change will likely alter dormancy dynamics in zooplankton, the basis of aquatic food webs, by altering two important hatching cues: mean temperatures during the ice-free season, and mean day length when lakes become ice free. Theory suggests that these changes could alter diversity, hatchling abundances and phenology within lakes, and that these responses may diverge across latitudes due to differences in optimal hatching cues and strategies. To examine the role of temperature and day length on hatching dynamics, we collected sediment from 25 lakes across a 1800 km latitudinal gradient and exposed sediment samples to a factorial combination of two photoperiods (12 and 16 h) and two temperatures (8 and 12 °C) representative of historical southern (short photoperiod, warm) and northern (long photoperiod, cool) lake conditions. We tested whether sensitivity to these hatching cues varies by latitudinal origin and differs among taxa. Higher temperatures advanced phenology for all taxa, and these advances were greatest for cladocerans followed by copepods and rotifers. Although phenology differed among taxa, the effect of temperature did not vary with latitude. The latitudinal origin of the egg bank influenced egg abundance and hatchling abundance and diversity, with these latter effects varying with taxa, temperature and photoperiod. Copepod hatchling abundances peaked at mid-latitudes in the high temperature and long photoperiod treatments, whereas hatchling abundances of other zooplankton were greatest at low latitudes and high temperature. The overall diversity of crustacean zooplankton (copepods and cladocerans) also reflected distinct responses of each taxa to our treatments, with the greatest diversity occurring at mid-latitudes (~56 °N) in the shorter photoperiod treatment. Our results demonstrate that hatching cues

  15. Effects of Climate Change on Extreme Streamflow Risks in the Olympic National Park

    NASA Astrophysics Data System (ADS)

    Tohver, I. M.; Lee, S.; Hamlet, A.

    2011-12-01

    Conventionally, natural resource management practices are designed within the framework that past conditions serve as a baseline for future conditions. However, the warmer future climate projected for the Pacific Northwest will alter the region's flood and low flow risks, posing considerable challenges to resource managers in the Olympic National Forest (ONF) and Olympic National Park (ONP). Shifts in extreme streamflow will influence two key management objectives in the ONF and ONP: the protection of wildlife and the maintenance of road infrastructure. The ONF is charged with managing habitat for species listed under the Endangered Species Act (ESA), and with maintaining the network of forest roads and culverts. Climate-induced increases in flood severity will introduce additional challenges in road and culvert design. Furthermore, the aging road infrastructure and more extreme summer low flows will compromise aquatic habitats, intrinsic to the health of threatened and endangered fish species listed under the ESA. Current practice uses estimates of Q100 (or the peak flow with an estimated 100 year return frequency) as the standard metric for stream crossing design. Simple regression models relating annual precipitation and basin area to Q100 are used in the design process. Low flow estimates are based on historical streamflow data to calculate the 7-day consecutive lowest flow with a 10-year return interval, or 7Q10. Under the projections a changing climate, these methods for estimating extreme flows are ill equipped to capture the complex and spatially varying effects of seasonal changes in temperature, precipitation, and snowpack on extreme flow risk. As an alternative approach, this study applies a physically-based hydrologic model to estimate historical and future flood risk at 1/16th degree (latitude/longitude) resolution (about 32 km2). We downscaled climate data derived from 10 global climate models to use as input for the Variable Infiltration Capacity

  16. Recent Advances in Regional Climate System Modeling and ClimateChange Analyses of Extreme Heat

    SciTech Connect

    Miller, Norman L.

    2004-09-24

    During the period May 2003 to May 2004, there were two CEC/PIER funded primary research activities by the Atmosphere and Ocean Sciences Group/Earth Science Division at LBNL. These activities are the implementation and testing of the National Center for Atmospheric Research Community Land Model (CLM) into MM5, and the analysis of extreme heat days under a new set of climate simulations. The new version of MM5,MM5-CLM, has been tested for a 90 day snowmelt period in the northwestern U.S. Results show that this new code upgrade, as compared to the MM5-NOAH, has improved snowmelt, temperature, and precipitation when compared to observations. These are due in part to a subgrid scheme,advanced snow processes, and advanced vegetation. The climate change analysis is the upper and lower IPCC Special Report on Emission Scenarios, representing fossil fuel intensive and energy conserving future emission scenarios, and medium and low sensitivity Global Climate Models. Results indicate that California cities will see increases in the number of heat wave and temperature threshold days from two to six times.These results may be viewed as potential outcomes based on today's decisions on emissions.

  17. Simulated trends of extreme climate indices for the Carpathian basin using outputs of different regional climate models

    NASA Astrophysics Data System (ADS)

    Pongracz, R.; Bartholy, J.; Szabo, P.; Pieczka, I.; Torma, C. S.

    2009-04-01

    Regional climatological effects of global warming may be recognized not only in shifts of mean temperature and precipitation, but in the frequency or intensity changes of different climate extremes. Several climate extreme indices are analyzed and compared for the Carpathian basin (located in Central/Eastern Europe) following the guidelines suggested by the joint WMO-CCl/CLIVAR Working Group on climate change detection. Our statistical trend analysis includes the evaluation of several extreme temperature and precipitation indices, e.g., the numbers of severe cold days, winter days, frost days, cold days, warm days, summer days, hot days, extremely hot days, cold nights, warm nights, the intra-annual extreme temperature range, the heat wave duration, the growing season length, the number of wet days (using several threshold values defining extremes), the maximum number of consecutive dry days, the highest 1-day precipitation amount, the greatest 5-day rainfall total, the annual fraction due to extreme precipitation events, etc. In order to evaluate the future trends (2071-2100) in the Carpathian basin, daily values of meteorological variables are obtained from the outputs of various regional climate model (RCM) experiments accomplished in the frame of the completed EU-project PRUDENCE (Prediction of Regional scenarios and Uncertainties for Defining EuropeaN Climate change risks and Effects). Horizontal resolution of the applied RCMs is 50 km. Both scenarios A2 and B2 are used to compare past and future trends of the extreme climate indices for the Carpathian basin. Furthermore, fine-resolution climate experiments of two additional RCMs adapted and run at the Department of Meteorology, Eotvos Lorand University are used to extend the trend analysis of climate extremes for the Carpathian basin. (1) Model PRECIS (run at 25 km horizontal resolution) was developed at the UK Met Office, Hadley Centre, and it uses the boundary conditions from the HadCM3 GCM. (2) Model Reg

  18. Climate Extreme Effects on the Chemical Composition of Temperate Grassland Species under Ambient and Elevated CO2: A Comparison of Fructan and Non-Fructan Accumulators

    PubMed Central

    Zinta, Gaurav; Van den Ende, Wim; Janssens, Ivan A.; Asard, Han

    2014-01-01

    Elevated CO2 concentrations and extreme climate events, are two increasing components of the ongoing global climatic change factors, may alter plant chemical composition and thereby their economic and ecological characteristics, e.g. nutritional quality and decomposition rates. To investigate the impact of climate extremes on tissue quality, four temperate grassland species: the fructan accumulating grasses Lolium perenne, Poa pratensis, and the nitrogen (N) fixing legumes Medicago lupulina and Lotus corniculatus were subjected to water deficit at elevated temperature (+3°C), under ambient CO2 (392 ppm) and elevated CO2 (620 ppm). As a general observation, the effects of the climate extreme were larger and more ubiquitous in combination with elevated CO2. The imposed climate extreme increased non-structural carbohydrate and phenolics in all species, whereas it increased lignin in legumes and decreased tannins in grasses. However, there was no significant effect of climate extreme on structural carbohydrates, proteins, lipids and mineral contents and stoichiometric ratios. In combination with elevated CO2, climate extreme elicited larger increases in fructan and sucrose content in the grasses without affecting the total carbohydrate content, while it significantly increased total carbohydrates in legumes. The accumulation of carbohydrates in legumes was accompanied by higher activity of sucrose phosphate synthase, sucrose synthase and ADP-Glc pyrophosphorylase. In the legumes, elevated CO2 in combination with climate extreme reduced protein, phosphorus (P) and magnesium (Mg) contents and the total element:N ratio and it increased phenol, lignin, tannin, carbon (C), nitrogen (N) contents and C:N, C:P and N:P ratios. On the other hand, the tissue composition of the fructan accumulating grasses was not affected at this level, in line with recent views that fructans contribute to cellular homeostasis under stress. It is speculated that quality losses will be less

  19. Climate extreme effects on the chemical composition of temperate grassland species under ambient and elevated CO2: a comparison of fructan and non-fructan accumulators.

    PubMed

    AbdElgawad, Hamada; Peshev, Darin; Zinta, Gaurav; Van den Ende, Wim; Janssens, Ivan A; Asard, Han

    2014-01-01

    Elevated CO2 concentrations and extreme climate events, are two increasing components of the ongoing global climatic change factors, may alter plant chemical composition and thereby their economic and ecological characteristics, e.g. nutritional quality and decomposition rates. To investigate the impact of climate extremes on tissue quality, four temperate grassland species: the fructan accumulating grasses Lolium perenne, Poa pratensis, and the nitrogen (N) fixing legumes Medicago lupulina and Lotus corniculatus were subjected to water deficit at elevated temperature (+3°C), under ambient CO2 (392 ppm) and elevated CO2 (620 ppm). As a general observation, the effects of the climate extreme were larger and more ubiquitous in combination with elevated CO2. The imposed climate extreme increased non-structural carbohydrate and phenolics in all species, whereas it increased lignin in legumes and decreased tannins in grasses. However, there was no significant effect of climate extreme on structural carbohydrates, proteins, lipids and mineral contents and stoichiometric ratios. In combination with elevated CO2, climate extreme elicited larger increases in fructan and sucrose content in the grasses without affecting the total carbohydrate content, while it significantly increased total carbohydrates in legumes. The accumulation of carbohydrates in legumes was accompanied by higher activity of sucrose phosphate synthase, sucrose synthase and ADP-Glc pyrophosphorylase. In the legumes, elevated CO2 in combination with climate extreme reduced protein, phosphorus (P) and magnesium (Mg) contents and the total element:N ratio and it increased phenol, lignin, tannin, carbon (C), nitrogen (N) contents and C:N, C:P and N:P ratios. On the other hand, the tissue composition of the fructan accumulating grasses was not affected at this level, in line with recent views that fructans contribute to cellular homeostasis under stress. It is speculated that quality losses will be less

  20. Climate extreme effects on the chemical composition of temperate grassland species under ambient and elevated CO2: a comparison of fructan and non-fructan accumulators.

    PubMed

    AbdElgawad, Hamada; Peshev, Darin; Zinta, Gaurav; Van den Ende, Wim; Janssens, Ivan A; Asard, Han

    2014-01-01

    Elevated CO2 concentrations and extreme climate events, are two increasing components of the ongoing global climatic change factors, may alter plant chemical composition and thereby their economic and ecological characteristics, e.g. nutritional quality and decomposition rates. To investigate the impact of climate extremes on tissue quality, four temperate grassland species: the fructan accumulating grasses Lolium perenne, Poa pratensis, and the nitrogen (N) fixing legumes Medicago lupulina and Lotus corniculatus were subjected to water deficit at elevated temperature (+3°C), under ambient CO2 (392 ppm) and elevated CO2 (620 ppm). As a general observation, the effects of the climate extreme were larger and more ubiquitous in combination with elevated CO2. The imposed climate extreme increased non-structural carbohydrate and phenolics in all species, whereas it increased lignin in legumes and decreased tannins in grasses. However, there was no significant effect of climate extreme on structural carbohydrates, proteins, lipids and mineral contents and stoichiometric ratios. In combination with elevated CO2, climate extreme elicited larger increases in fructan and sucrose content in the grasses without affecting the total carbohydrate content, while it significantly increased total carbohydrates in legumes. The accumulation of carbohydrates in legumes was accompanied by higher activity of sucrose phosphate synthase, sucrose synthase and ADP-Glc pyrophosphorylase. In the legumes, elevated CO2 in combination with climate extreme reduced protein, phosphorus (P) and magnesium (Mg) contents and the total element:N ratio and it increased phenol, lignin, tannin, carbon (C), nitrogen (N) contents and C:N, C:P and N:P ratios. On the other hand, the tissue composition of the fructan accumulating grasses was not affected at this level, in line with recent views that fructans contribute to cellular homeostasis under stress. It is speculated that quality losses will be less

  1. Application of data on climate extremes for the southwestern United States

    NASA Astrophysics Data System (ADS)

    Redmond, K. T.; Fleishman, E.; Cayan, D. R.; Daudert, B.; Gershunov, A.

    2015-12-01

    We are improving the scientific capacity to evaluate responses of natural resources to climate extremes. We also are enhancing a platform for derivation of and access to customized climate information for the full extent or any subset of the southwestern United States. Extreme climate can have substantial effects on species, ecological and evolutionary processes, and the health of visitors to public lands. We are working with federal and state managers and with researchers who collaborate with decision-makers to use data on climate extremes to inform resource management. Current applications include sudden oak death, estuarine management, and fine-resolution manipulation of montane vegetation. To facilitate practical use of data on climate extremes, we are screening global climate models on the basis of their realism in representing natural regional patterns and extremes of temperature and precipitation, including those driven by El Niño and La Niña. We are assessing how well each model represents different climate elements. We also are delivering point and gridded observations and downscaled model projections, all at daily and 6 km resolution, on past and future climate extremes. Additionally, we are using the downscaled outputs to drive a hydrologic model and derive multiple probabilistic measures of water availability, flood, and drought. Moreover, we are extending the capacity of the Southwest Climate and Environmental Information Collaborative (SCENIC; wrcc.dri.edu/csc/scenic), a product developed by the Western Regional Climate Center, to provide access to diverse observed and simulated data on regional weather and climate, particularly on extremes.

  2. Plant-soil interactions and soil carbon dynamics under climate extremes

    NASA Astrophysics Data System (ADS)

    Bahn, Michael

    2016-04-01

    Climate extremes have been suggested to increase significantly in intensity and frequency in the coming decades, and may influence ecosystem processes and the carbon cycle more profoundly than gradual climate warming. While there is a growing understanding of plant-soil interactions in extreme environments and from lab experiments, we still know very little about how such interactions affect soil carbon dynamics in real-world ecosystems exposed to climate extremes. In this talk I will give a brief overview of the topic and will present evidence from in-situ experiments on plant-soil interactions and their consequences for soil carbon dynamics under severe drought.

  3. Impacts of ocean albedo alteration on Arctic sea ice restoration and Northern Hemisphere climate

    DOE PAGES

    Cvijanovic, Ivana; Caldeira, Ken; MacMartin, Douglas G.

    2015-04-01

    The Arctic Ocean is expected to transition into a seasonally ice-free state by mid-century, enhancing Arctic warming and leading to substantial ecological and socio-economic challenges across the Arctic region. It has been proposed that artificially increasing high latitude ocean albedo could restore sea ice, but the climate impacts of such a strategy have not been previously explored. Motivated by this, we investigate the impacts of idealized high latitude ocean albedo changes on Arctic sea ice restoration and climate. In our simulated 4xCO₂ climate, imposing surface albedo alterations over the Arctic Ocean leads to partial sea ice recovery and a modestmore » reduction in Arctic warming. With the most extreme ocean albedo changes, imposed over the area 70°–90°N, September sea ice cover stabilizes at ~40% of its preindustrial value (compared to ~3% without imposed albedo modifications). This is accompanied by an annual mean Arctic surface temperature decrease of ~2 °C but no substantial global mean temperature decrease. Imposed albedo changes and sea ice recovery alter climate outside the Arctic region too, affecting precipitation distribution over parts of the continental United States and Northeastern Pacific. For example, following sea ice recovery, wetter and milder winter conditions are present in the Southwest United States while the East Coast experiences cooling. We conclude that although ocean albedo alteration could lead to some sea ice recovery, it does not appear to be an effective way of offsetting the overall effects of CO₂ induced global warming.« less

  4. Impacts of ocean albedo alteration on Arctic sea ice restoration and Northern Hemisphere climate

    SciTech Connect

    Cvijanovic, Ivana; Caldeira, Ken; MacMartin, Douglas G.

    2015-04-01

    The Arctic Ocean is expected to transition into a seasonally ice-free state by mid-century, enhancing Arctic warming and leading to substantial ecological and socio-economic challenges across the Arctic region. It has been proposed that artificially increasing high latitude ocean albedo could restore sea ice, but the climate impacts of such a strategy have not been previously explored. Motivated by this, we investigate the impacts of idealized high latitude ocean albedo changes on Arctic sea ice restoration and climate. In our simulated 4xCO₂ climate, imposing surface albedo alterations over the Arctic Ocean leads to partial sea ice recovery and a modest reduction in Arctic warming. With the most extreme ocean albedo changes, imposed over the area 70°–90°N, September sea ice cover stabilizes at ~40% of its preindustrial value (compared to ~3% without imposed albedo modifications). This is accompanied by an annual mean Arctic surface temperature decrease of ~2 °C but no substantial global mean temperature decrease. Imposed albedo changes and sea ice recovery alter climate outside the Arctic region too, affecting precipitation distribution over parts of the continental United States and Northeastern Pacific. For example, following sea ice recovery, wetter and milder winter conditions are present in the Southwest United States while the East Coast experiences cooling. We conclude that although ocean albedo alteration could lead to some sea ice recovery, it does not appear to be an effective way of offsetting the overall effects of CO₂ induced global warming.

  5. Are Extremes of Consumption in Eating Disorders Related to an Altered Balance between Reward and Inhibition?

    PubMed Central

    Wierenga, Christina E.; Ely, Alice; Bischoff-Grethe, Amanda; Bailer, Ursula F.; Simmons, Alan N.; Kaye, Walter H.

    2014-01-01

    The primary defining characteristic of a diagnosis of an eating disorder (ED) is the “disturbance of eating or eating-related behavior that results in the altered consumption or absorption of food” (DSM V; American Psychiatric Association, 2013). There is a spectrum, ranging from those who severely restrict eating and become emaciated on one end to those who binge and overconsume, usually accompanied by some form of compensatory behaviors, on the other. How can we understand reasons for such extremes of food consummatory behaviors? Recent work on obesity and substance use disorders has identified behaviors and neural pathways that play a powerful role in human consummatory behaviors. That is, corticostriatal limbic and dorsal cognitive neural circuitry can make drugs and food rewarding, but also engage self-control mechanisms that may inhibit their use. Importantly, there is considerable evidence that alterations of these systems also occur in ED. This paper explores the hypothesis that an altered balance of reward and inhibition contributes to altered extremes of response to salient stimuli, such as food. We will review recent studies that show altered sensitivity to reward and punishment in ED, with evidence of altered activity in corticostriatal and insula processes with respect to monetary gains or losses, and tastes of palatable foods. We will also discuss evidence for a spectrum of extremes of inhibition and dysregulation behaviors in ED supported by studies suggesting that this is related to top-down self-control mechanisms. The lack of a mechanistic understanding of ED has thwarted efforts for evidence-based approaches to develop interventions. Understanding how ED behavior is encoded in neural circuits would provide a foundation for developing more specific and effective treatment approaches. PMID:25538579

  6. Synergy of extreme drought and shrub invasion reduce ecosystem functioning and resilience in water-limited climates.

    PubMed

    Caldeira, Maria C; Lecomte, Xavier; David, Teresa S; Pinto, Joaquim G; Bugalho, Miguel N; Werner, Christiane

    2015-10-13

    Extreme drought events and plant invasions are major drivers of global change that can critically affect ecosystem functioning and alter ecosystem-atmosphere exchange. Invaders are expanding worldwide and extreme drought events are projected to increase in frequency and intensity. However, very little is known on how these drivers may interact to affect the functioning and resilience of ecosystems to extreme events. Using a manipulative shrub removal experiment and the co-occurrence of an extreme drought event (2011/2012) in a Mediterranean woodland, we show that native shrub invasion and extreme drought synergistically reduced ecosystem transpiration and the resilience of key-stone oak tree species. Ecosystem transpiration was dominated by the water use of the invasive shrub Cistus ladanifer, which further increased after the extreme drought event. Meanwhile, the transpiration of key-stone tree species decreased, indicating a competitive advantage in favour of the invader. Our results suggest that in Mediterranean-type climates the invasion of water spending species and projected recurrent extreme drought events may synergistically cause critical drought tolerance thresholds of key-stone tree species to be surpassed, corroborating observed higher tree mortality in the invaded ecosystems. Ultimately, this may shift seasonally water limited ecosystems into less desirable alternative states dominated by water spending invasive shrubs.

  7. Synergy of extreme drought and shrub invasion reduce ecosystem functioning and resilience in water-limited climates

    PubMed Central

    Caldeira, Maria C.; Lecomte, Xavier; David, Teresa S.; Pinto, Joaquim G.; Bugalho, Miguel N.; Werner, Christiane

    2015-01-01

    Extreme drought events and plant invasions are major drivers of global change that can critically affect ecosystem functioning and alter ecosystem-atmosphere exchange. Invaders are expanding worldwide and extreme drought events are projected to increase in frequency and intensity. However, very little is known on how these drivers may interact to affect the functioning and resilience of ecosystems to extreme events. Using a manipulative shrub removal experiment and the co-occurrence of an extreme drought event (2011/2012) in a Mediterranean woodland, we show that native shrub invasion and extreme drought synergistically reduced ecosystem transpiration and the resilience of key-stone oak tree species. Ecosystem transpiration was dominated by the water use of the invasive shrub Cistus ladanifer, which further increased after the extreme drought event. Meanwhile, the transpiration of key-stone tree species decreased, indicating a competitive advantage in favour of the invader. Our results suggest that in Mediterranean-type climates the invasion of water spending species and projected recurrent extreme drought events may synergistically cause critical drought tolerance thresholds of key-stone tree species to be surpassed, corroborating observed higher tree mortality in the invaded ecosystems. Ultimately, this may shift seasonally water limited ecosystems into less desirable alternative states dominated by water spending invasive shrubs. PMID:26461978

  8. Synergy of extreme drought and shrub invasion reduce ecosystem functioning and resilience in water-limited climates

    NASA Astrophysics Data System (ADS)

    Caldeira, Maria C.; Lecomte, Xavier; David, Teresa S.; Pinto, Joaquim G.; Bugalho, Miguel N.; Werner, Christiane

    2015-10-01

    Extreme drought events and plant invasions are major drivers of global change that can critically affect ecosystem functioning and alter ecosystem-atmosphere exchange. Invaders are expanding worldwide and extreme drought events are projected to increase in frequency and intensity. However, very little is known on how these drivers may interact to affect the functioning and resilience of ecosystems to extreme events. Using a manipulative shrub removal experiment and the co-occurrence of an extreme drought event (2011/2012) in a Mediterranean woodland, we show that native shrub invasion and extreme drought synergistically reduced ecosystem transpiration and the resilience of key-stone oak tree species. Ecosystem transpiration was dominated by the water use of the invasive shrub Cistus ladanifer, which further increased after the extreme drought event. Meanwhile, the transpiration of key-stone tree species decreased, indicating a competitive advantage in favour of the invader. Our results suggest that in Mediterranean-type climates the invasion of water spending species and projected recurrent extreme drought events may synergistically cause critical drought tolerance thresholds of key-stone tree species to be surpassed, corroborating observed higher tree mortality in the invaded ecosystems. Ultimately, this may shift seasonally water limited ecosystems into less desirable alternative states dominated by water spending invasive shrubs.

  9. Synergy of extreme drought and shrub invasion reduce ecosystem functioning and resilience in water-limited climates.

    PubMed

    Caldeira, Maria C; Lecomte, Xavier; David, Teresa S; Pinto, Joaquim G; Bugalho, Miguel N; Werner, Christiane

    2015-01-01

    Extreme drought events and plant invasions are major drivers of global change that can critically affect ecosystem functioning and alter ecosystem-atmosphere exchange. Invaders are expanding worldwide and extreme drought events are projected to increase in frequency and intensity. However, very little is known on how these drivers may interact to affect the functioning and resilience of ecosystems to extreme events. Using a manipulative shrub removal experiment and the co-occurrence of an extreme drought event (2011/2012) in a Mediterranean woodland, we show that native shrub invasion and extreme drought synergistically reduced ecosystem transpiration and the resilience of key-stone oak tree species. Ecosystem transpiration was dominated by the water use of the invasive shrub Cistus ladanifer, which further increased after the extreme drought event. Meanwhile, the transpiration of key-stone tree species decreased, indicating a competitive advantage in favour of the invader. Our results suggest that in Mediterranean-type climates the invasion of water spending species and projected recurrent extreme drought events may synergistically cause critical drought tolerance thresholds of key-stone tree species to be surpassed, corroborating observed higher tree mortality in the invaded ecosystems. Ultimately, this may shift seasonally water limited ecosystems into less desirable alternative states dominated by water spending invasive shrubs. PMID:26461978

  10. The impact of climate extremes on US agricultural production and the buffering impacts of irrigation

    NASA Astrophysics Data System (ADS)

    Troy, Tara J.; Kipgen, Chinpihoi; Pal, Indrani

    2014-05-01

    In recent years, droughts and floods have occurred over many of the major growing regions of the world, resulting in decreased agricultural production and increased global food prices. Many climate projections call for more frequent extreme events, which could have significant impacts on agricultural yields and water resources in irrigated agricultural regions. In order to better understand the potential impact of climate extremes and the spatial heterogeneity of those impacts, we examine the associations between climate and irrigated and rain fed crop yields, focusing on four main staple crops: wheat, rice, soy, and maize. Because the United States has high spatial resolution data for both yields and weather variables, the analysis focuses on the impact of multiple extremes over these four crops in the US using statistical methods that do not require any assumptions of functional relationships between yields and weather variables. Irrigated and rain fed agricultural yields are analyzed separately to understand the role irrigation plays either as a buffering against climate variability and extremes such as drought, heat waves, and extended dry spells or a mechanism that leads to varied relationships between extremes of climate and yield fluctuations. These results demonstrate that irrigation has varying effects depending on the region, growing season timing, crop type, and type of climate extreme. This work has important implications for future planning of the coupled water-food system and its vulnerabilities to climate.

  11. Impact of Climate Change on extreme flows across Great Britain: a comparison of extreme value distributions and uncertainty assessment.

    NASA Astrophysics Data System (ADS)

    Collet, Lila; Beevers, Lindsay; Prudhomme, Christel

    2016-04-01

    Floods are the most common and widely distributed natural risk to life and property worldwide, causing over £6B worth of damage to the UK since 2000. Climate projections are predicted to result in the increase of UK properties at risk from flooding. It thus becomes urgent to assess the possible impact of these changes on extreme high flows in particular, and evaluate the uncertainties related to these projections. This paper aims to assess the changes in extreme runoff for the 1:100 year return period event across Great Britain as a result of climate change. It is based on the Future Flow database and analyses daily runoff over 1961-2098 for 281 gauging stations. The Generalized Extreme Value (GEV) and Generalized Pareto (GP) distribution functions are automatically fitted for 11 climate-change ensembles over the baseline (1961-1990) and the 2080s (2069-2098) for each gauging station. The analysis evaluates the uncertainty related to the Extreme Value (EV) distributions, and the uncertainty related to the climate model parameterization. Then it assesses return levels with combined uncertainties across Great Britain for both EV distributions. Ultimately, this work gives a national picture of extreme flows assessed by the two methods and allows a direct comparison between them. Results show that the GP distribution computes higher runoff estimates than the GEV distribution. Generally, the uncertainties associated with both distributions are similar, but the GP computes significantly higher uncertainties for stations in the south and southeast of England. From the baseline to the 2080s horizon, the GEV distribution shows variable runoff trends across Great Britain, while the GP distribution shows an increasing trend of return level estimate and uncertainties, especially in the northeast and southeast of England. The lowest climate model and extreme value uncertainty is generally seen across the west coast of Great Britain. In terms of uncertainty, with the GEV

  12. Impacts of Climate Extremes on Gross Primary Productivity at Multiple Spatial Scales

    NASA Astrophysics Data System (ADS)

    Kim, Soyoun; Ryu, Youngryel; Jiang, Chongya

    2016-04-01

    Climate extreme events have made significant impacts on terrestrial carbon cycles. Recent studies on detection and attribution of climate extreme events and their impact on carbon cycles used coarse spatial resolution data such as 0.5 degree. The coarse resolution data might miss important climate extremes and their impacts on GPP. To fill this research gap, we use a new global GPP product derived from a process-based model, the Breathing Earth System Simulator (BESS). The BESS takes full advantages of MODIS/AVHRR land and atmosphere products, providing global GPP product in 1 km resolution from 2000 to 2015 and 1/12 degree resolution from 1982 to 1999. We first integrate the BESS GPP products to 0.5 degree (1982-2015) and apply the method of Zscheischler et al. (2013). To test the impacts of spatial resolutions on detecting extreme events, we enhance spatial resolutions of the BESS GPP from 0.5 degree to 0.25, 0.125, and 1/12 degrees and quantify the variations of areas which experienced climate extremes. We subsequently investigate hotspot regions where the extremes occur using fine resolution GPP data at 1/12 degree (1982-2015), then analyze the causes of the extreme events that substantially decreased GPP by using precipitation, air temperature, and frost. This study could improve the understanding of the relationship between climate extremes and the carbon cycle at multiple spatial scales.

  13. Climate Change Extreme Events: Meeting the Information Needs of Water Resource Managers

    NASA Astrophysics Data System (ADS)

    Quay, R.; Garfin, G. M.; Dominguez, F.; Hirschboeck, K. K.; Woodhouse, C. A.; Guido, Z.; White, D. D.

    2013-12-01

    Information about climate has long been used by water managers to develop short term and long term plans and strategies for regional and local water resources. Inherent within longer term forecasts is an element of uncertainty, which is particularly evident in Global Climate model results for precipitation. For example in the southwest estimates in the flow of the Colorado River based on GCM results indicate changes from 120% or current flow to 60%. Many water resource managers are now using global climate model down scaled estimates results as indications of potential climate change as part of that planning. They are addressing the uncertainty within these estimates by using an anticipatory planning approach looking at a range of possible futures. One aspect of climate that is important for such planning are estimates of future extreme storm (short term) and drought (long term) events. However, the climate science of future possible changes in extreme events is less mature than general climate change science. At a recent workshop among climate scientists and water managers in the southwest, it was concluded the science of climate change extreme events is at least a decade away from being robust enough to be useful for water managers in their water resource management activities. However, it was proposed that there are existing estimates and records of past flooding and drought events that could be combined with general climate change science to create possible future events. These derived events could be of sufficient detail to be used by water resource managers until such time that the science of extreme events is able to provide more detailed estimates. Based on the results of this workshop and other work being done by the Decision Center for a Desert City at Arizona State University and the Climate Assessment for the Southwest center at University of Arizona., this article will 1) review what are the extreme event data needs of Water Resource Managers in the

  14. Does Nudging Squelch the Extremes in Regional Climate Modeling?

    EPA Science Inventory

    An important question in regional climate downscaling is whether to constrain (nudge) the interior of the limited-area domain toward the larger-scale driving fields. Prior research has demonstrated that interior nudging can increase the skill of regional climate predictions origin...

  15. Impacts of different climate change regimes and extreme climatic events on an alpine meadow community

    PubMed Central

    Alatalo, Juha M.; Jägerbrand, Annika K.; Molau, Ulf

    2016-01-01

    Climate variability is expected to increase in future but there exist very few experimental studies that apply different warming regimes on plant communities over several years. We studied an alpine meadow community under three warming regimes over three years. Treatments consisted of (a) a constant level of warming with open-top chambers (ca. 1.9 °C above ambient), (b) yearly stepwise increases in warming (increases of ca. 1.0, 1.9 and 3.5 °C), and (c) pulse warming, a single first-year pulse event of warming (increase of ca. 3.5 °C). Pulse warming and stepwise warming was hypothesised to cause distinct first-year and third-year effects, respectively. We found support for both hypotheses; however, the responses varied among measurement levels (whole community, canopy, bottom layer, and plant functional groups), treatments, and time. Our study revealed complex responses of the alpine plant community to the different experimentally imposed climate warming regimes. Plant cover, height and biomass frequently responded distinctly to the constant level of warming, the stepwise increase in warming and the extreme pulse-warming event. Notably, we found that stepwise warming had an accumulating effect on biomass, the responses to the different warming regimes varied among functional groups, and the short-term perturbations had negative effect on species richness and diversity PMID:26888225

  16. Impacts of different climate change regimes and extreme climatic events on an alpine meadow community.

    PubMed

    Alatalo, Juha M; Jägerbrand, Annika K; Molau, Ulf

    2016-02-18

    Climate variability is expected to increase in future but there exist very few experimental studies that apply different warming regimes on plant communities over several years. We studied an alpine meadow community under three warming regimes over three years. Treatments consisted of (a) a constant level of warming with open-top chambers (ca. 1.9 °C above ambient), (b) yearly stepwise increases in warming (increases of ca. 1.0, 1.9 and 3.5 °C), and (c) pulse warming, a single first-year pulse event of warming (increase of ca. 3.5 °C). Pulse warming and stepwise warming was hypothesised to cause distinct first-year and third-year effects, respectively. We found support for both hypotheses; however, the responses varied among measurement levels (whole community, canopy, bottom layer, and plant functional groups), treatments, and time. Our study revealed complex responses of the alpine plant community to the different experimentally imposed climate warming regimes. Plant cover, height and biomass frequently responded distinctly to the constant level of warming, the stepwise increase in warming and the extreme pulse-warming event. Notably, we found that stepwise warming had an accumulating effect on biomass, the responses to the different warming regimes varied among functional groups, and the short-term perturbations had negative effect on species richness and diversity.

  17. Impacts of different climate change regimes and extreme climatic events on an alpine meadow community

    NASA Astrophysics Data System (ADS)

    Alatalo, Juha M.; Jägerbrand, Annika K.; Molau, Ulf

    2016-02-01

    Climate variability is expected to increase in future but there exist very few experimental studies that apply different warming regimes on plant communities over several years. We studied an alpine meadow community under three warming regimes over three years. Treatments consisted of (a) a constant level of warming with open-top chambers (ca. 1.9 °C above ambient), (b) yearly stepwise increases in warming (increases of ca. 1.0, 1.9 and 3.5 °C), and (c) pulse warming, a single first-year pulse event of warming (increase of ca. 3.5 °C). Pulse warming and stepwise warming was hypothesised to cause distinct first-year and third-year effects, respectively. We found support for both hypotheses; however, the responses varied among measurement levels (whole community, canopy, bottom layer, and plant functional groups), treatments, and time. Our study revealed complex responses of the alpine plant community to the different experimentally imposed climate warming regimes. Plant cover, height and biomass frequently responded distinctly to the constant level of warming, the stepwise increase in warming and the extreme pulse-warming event. Notably, we found that stepwise warming had an accumulating effect on biomass, the responses to the different warming regimes varied among functional groups, and the short-term perturbations had negative effect on species richness and diversity

  18. Why climate change will invariably alter selection pressures on phenology

    PubMed Central

    Gienapp, Phillip; Reed, Thomas E.; Visser, Marcel E.

    2014-01-01

    The seasonal timing of lifecycle events is closely linked to individual fitness and hence, maladaptation in phenological traits may impact population dynamics. However, few studies have analysed whether and why climate change will alter selection pressures and hence possibly induce maladaptation in phenology. To fill this gap, we here use a theoretical modelling approach. In our models, the phenologies of consumer and resource are (potentially) environmentally sensitive and depend on two different but correlated environmental variables. Fitness of the consumer depends on the phenological match with the resource. Because we explicitly model the dependence of the phenologies on environmental variables, we can test how differential (heterogeneous) versus equal (homogeneous) rates of change in the environmental variables affect selection on consumer phenology. As expected, under heterogeneous change, phenotypic plasticity is insufficient and thus selection on consumer phenology arises. However, even homogeneous change leads to directional selection on consumer phenology. This is because the consumer reaction norm has historically evolved to be flatter than the resource reaction norm, owing to time lags and imperfect cue reliability. Climate change will therefore lead to increased selection on consumer phenology across a broad range of situations. PMID:25165771

  19. Why climate change will invariably alter selection pressures on phenology.

    PubMed

    Gienapp, Phillip; Reed, Thomas E; Visser, Marcel E

    2014-10-22

    The seasonal timing of lifecycle events is closely linked to individual fitness and hence, maladaptation in phenological traits may impact population dynamics. However, few studies have analysed whether and why climate change will alter selection pressures and hence possibly induce maladaptation in phenology. To fill this gap, we here use a theoretical modelling approach. In our models, the phenologies of consumer and resource are (potentially) environmentally sensitive and depend on two different but correlated environmental variables. Fitness of the consumer depends on the phenological match with the resource. Because we explicitly model the dependence of the phenologies on environmental variables, we can test how differential (heterogeneous) versus equal (homogeneous) rates of change in the environmental variables affect selection on consumer phenology. As expected, under heterogeneous change, phenotypic plasticity is insufficient and thus selection on consumer phenology arises. However, even homogeneous change leads to directional selection on consumer phenology. This is because the consumer reaction norm has historically evolved to be flatter than the resource reaction norm, owing to time lags and imperfect cue reliability. Climate change will therefore lead to increased selection on consumer phenology across a broad range of situations.

  20. Climate Extremes Events and their Connection with Runoff in the Yellow River Basin

    NASA Astrophysics Data System (ADS)

    Hu, Caihong; Lei, Deyi; He, Huli; Wang, Jijun

    2016-04-01

    This study analyzes the temporal and spatial distribution of runoff and their relationship with the extreme values of eight climate indices, based on observational data from 143 meteorological stations and 6 hydrological stations across the basin. The eight core indices selected from the STARDEX projects reflect rather moderate extremes. Statistics methods and GIS technology were be used for analysis on the relationship and distribution characteristics. We analyzed the reason of runoff change and the relationship between the climate extreme events and observed runoff from six hydrological stations. Our results show that the annual and seasonal runoff showed obviously decrease tendency. Sharp decreases of runoff in six hydrological stations occurred in the late 1980s and 1990s. It can be seen that the decrease in runoff was caused by climate change, increased demands for water supply, land use change, etc. And the difference between the magnitude of the increasing and decreasing trends for different indices at different stations suggests that the climate extremes and environment change resulted in a decrease in runoff. The results also show that the shortage of water resources will become more pronounced in the Yellow River Basin with the increased occurrence of climate extremes. The results presented here will help to improve our understanding of the changes to climate extremes, and provide a basis for further investigation.

  1. Detection and Attribution of Simulated Climatic Extreme Events and Impacts: High Sensitivity to Bias Correction

    NASA Astrophysics Data System (ADS)

    Sippel, S.; Otto, F. E. L.; Forkel, M.; Allen, M. R.; Guillod, B. P.; Heimann, M.; Reichstein, M.; Seneviratne, S. I.; Kirsten, T.; Mahecha, M. D.

    2015-12-01

    Understanding, quantifying and attributing the impacts of climatic extreme events and variability is crucial for societal adaptation in a changing climate. However, climate model simulations generated for this purpose typically exhibit pronounced biases in their output that hinders any straightforward assessment of impacts. To overcome this issue, various bias correction strategies are routinely used to alleviate climate model deficiencies most of which have been criticized for physical inconsistency and the non-preservation of the multivariate correlation structure. We assess how biases and their correction affect the quantification and attribution of simulated extremes and variability in i) climatological variables and ii) impacts on ecosystem functioning as simulated by a terrestrial biosphere model. Our study demonstrates that assessments of simulated climatic extreme events and impacts in the terrestrial biosphere are highly sensitive to bias correction schemes with major implications for the detection and attribution of these events. We introduce a novel ensemble-based resampling scheme based on a large regional climate model ensemble generated by the distributed weather@home setup[1], which fully preserves the physical consistency and multivariate correlation structure of the model output. We use extreme value statistics to show that this procedure considerably improves the representation of climatic extremes and variability. Subsequently, biosphere-atmosphere carbon fluxes are simulated using a terrestrial ecosystem model (LPJ-GSI) to further demonstrate the sensitivity of ecosystem impacts to the methodology of bias correcting climate model output. We find that uncertainties arising from bias correction schemes are comparable in magnitude to model structural and parameter uncertainties. The present study consists of a first attempt to alleviate climate model biases in a physically consistent way and demonstrates that this yields improved simulations of

  2. Hydrologic regime alteration of a Mediterranean catchment under climate change projection

    NASA Astrophysics Data System (ADS)

    Sellami, Haykel; Benabdallah, Sihem; La Jeunesse, Isabelle; Herrmann, Frank; Vanclooster, Marnik

    2014-05-01

    Most of the climate models projections for the Mediterranean basin have showed that the region will likely to experience a general tendency towards drier climate conditions with decreases in total precipitation, increases in temperature, alterations in the rainfall extreme events and droughts frequency (IPCC, 2007; Giorgi and Lionello, 2008; López-Moreno et al., 2011). The region is already suffering from water resources scarcity and vulnerability which are expected to amplify in the next century (Ludwig et al., 2011; Schneider et al., 2013). Therefore, assessing the impact of climate change on the hydrologic regime of Mediterranean catchments is with a major concern not only to scientist but also to water resources policy makers and general public. However, most of the climate change impact studies focus on the flow regime on global or regional scale rather than on the catchment scale which is more useful and more appropriate to guide practical mitigation and adaptation policy. This is because hydro-climate modeling at the local scale is confronted to the variability in climate, topography, geology, lack of observations and anthropogenic activities within the catchment. Furthermore, it is well recognized that hydrological and climate models forecasts are always affected with uncertainty making the assessment of climate change impact on Mediterranean catchment hydrology more challenging. This work aims to assess the impact of climate change on a Mediterranean catchment located in North Africa (the Chiba catchment in northeast Tunisia) through a conjunctive use of physically based hydrological model (SWAT) driven with four climate models*. Quantification of the impact of climate change has been conducted by means of the Indicators of Hydrologic Alteration (Richter et al., 1996) which are also ecologically meaningful. By comparing changes in these indicators in the reference period (1971-2000) to the projected ones in the future (2041-2070), it was possible to draw

  3. Establishment and performance of an experimental green roof under extreme climatic conditions.

    PubMed

    Klein, Petra M; Coffman, Reid

    2015-04-15

    Green roofs alter the surface energy balance and can help in mitigating urban heat islands. However, the cooling of green roofs due to evapotranspiration strongly depends on the climatic conditions, and vegetation type and density. In the Southern Central Plains of the United States, extreme weather events, such as high winds, heat waves and drought conditions pose challenges for successful implementation of green roofs, and likely alter their standard performance. The National Weather Center Experimental Green Roof, an interdisciplinary research site established in 2010 in Norman, OK, aimed to investigate the ecological performance and surface energy balance of green roof systems. Starting in May 2010, 26 months of vegetation studies were conducted and the radiation balance, air temperature, relative humidity, and buoyancy fluxes were monitored at two meteorological stations during April-October 2011. The establishment of a vegetative community trended towards prairie plant dominance. High mortality of succulents and low germination of grasses and herbaceous plants contributed to low vegetative coverage. In this condition succulent diversity declined. Bouteloua gracilis and Delosperma cooperi showed typological dominance in harsh climatic conditions, while Sedum species experienced high mortality. The plant community diversified through volunteers such as Euphorbia maculate and Portulaca maculate. Net radiation measured at a green-roof meteorological station was higher than at a control station over the original, light-colored roofing material. These findings indicate that the albedo of the green roof was lower than the albedo of the original roofing material. The low vegetative coverage during the heat and drought conditions in 2011, which resulted in the dark substrate used in the green roof containers being exposed, likely contributed to the low albedo values. Nevertheless, air temperatures and buoyancy fluxes were often lower over the green roof indicating

  4. Establishment and performance of an experimental green roof under extreme climatic conditions.

    PubMed

    Klein, Petra M; Coffman, Reid

    2015-04-15

    Green roofs alter the surface energy balance and can help in mitigating urban heat islands. However, the cooling of green roofs due to evapotranspiration strongly depends on the climatic conditions, and vegetation type and density. In the Southern Central Plains of the United States, extreme weather events, such as high winds, heat waves and drought conditions pose challenges for successful implementation of green roofs, and likely alter their standard performance. The National Weather Center Experimental Green Roof, an interdisciplinary research site established in 2010 in Norman, OK, aimed to investigate the ecological performance and surface energy balance of green roof systems. Starting in May 2010, 26 months of vegetation studies were conducted and the radiation balance, air temperature, relative humidity, and buoyancy fluxes were monitored at two meteorological stations during April-October 2011. The establishment of a vegetative community trended towards prairie plant dominance. High mortality of succulents and low germination of grasses and herbaceous plants contributed to low vegetative coverage. In this condition succulent diversity declined. Bouteloua gracilis and Delosperma cooperi showed typological dominance in harsh climatic conditions, while Sedum species experienced high mortality. The plant community diversified through volunteers such as Euphorbia maculate and Portulaca maculate. Net radiation measured at a green-roof meteorological station was higher than at a control station over the original, light-colored roofing material. These findings indicate that the albedo of the green roof was lower than the albedo of the original roofing material. The low vegetative coverage during the heat and drought conditions in 2011, which resulted in the dark substrate used in the green roof containers being exposed, likely contributed to the low albedo values. Nevertheless, air temperatures and buoyancy fluxes were often lower over the green roof indicating

  5. Hydrologic Response to Climate Variability, Climate Change, and Climate Extreme in the U.S.: Climate Model Evaluation and Projections

    SciTech Connect

    Leung, Lai R.; Qian, Yun

    2005-08-01

    Water resources are sensitive to climate variability and change; predictions of seasonal to interannual climate variations and projections of long-term climate trends can provide significant values in managing water resources. This study examines the control (1975–1995) and future (1995–2100) climate simulated by a global climate model (GCM) and a regional climate simulation driven by the GCM control simulation for the U.S. Comparison of the regional climate simulation with observations across 13 subregions showed that the simulation captured the seasonality and the distributions of precipitation rate quite well. The GCM control and climate change simulations showed that, as a result of a 1% increase in greenhouse gas concentrations per year, there will be a warming of 2–3°C across the U.S. from 2000 to 2100. Although precipitation is not projected to change during this century, the warming trend will increase evapotranspiration to reduce annual basin mean runoff over five subregions along the coastal and south-central U.S.

  6. Extreme climatic events change the dynamics and invasibility of semi-arid annual plant communities.

    PubMed

    Jiménez, Milagros A; Jaksic, Fabian M; Armesto, Juan J; Gaxiola, Aurora; Meserve, Peter L; Kelt, Douglas A; Gutiérrez, Julio R

    2011-12-01

    Extreme climatic events represent disturbances that change the availability of resources. We studied their effects on annual plant assemblages in a semi-arid ecosystem in north-central Chile. We analysed 130 years of precipitation data using generalised extreme-value distribution to determine extreme events, and multivariate techniques to analyse 20 years of plant cover data of 34 native and 11 exotic species. Extreme drought resets the dynamics of the system and renders it susceptible to invasion. On the other hand, by favouring native annuals, moderately wet events change species composition and allow the community to be resilient to extreme drought. The probability of extreme drought has doubled over the last 50 years. Therefore, investigations on the interaction of climate change and biological invasions are relevant to determine the potential for future effects on the dynamics of semi-arid annual plant communities.

  7. A multivariate extreme wave and storm surge climate emulator based on weather patterns

    NASA Astrophysics Data System (ADS)

    Rueda, A.; Camus, P.; Tomás, A.; Vitousek, S.; Méndez, F. J.

    2016-08-01

    Coastal floods often coincide with large waves, storm surge and tides. Thus, joint probability methods are needed to properly characterize extreme sea levels. This work introduces a statistical downscaling framework for multivariate extremes that relates the non-stationary behavior of coastal flooding events to the occurrence probability of daily weather patterns. The proposed method is based on recently-developed weather-type methods to predict extreme events (e.g., significant wave height, mean wave period, surge level) from large-scale sea-level pressure fields. For each weather type, variables of interest are modeled using Generalized Extreme Value (GEV) distributions and a Gaussian copula for modelling the interdependence between variables. The statistical dependence between consecutive days is addressed by defining a climate-based extremal index for each weather type. This work allows attribution of extreme events to specific weather conditions, enhancing the knowledge of climate-driven coastal flooding.

  8. A plant’s perspective of extremes: Terrestrial plant responses to changing climatic variability

    PubMed Central

    Reyer, C.; Leuzinger, S.; Rammig, A.; Wolf, A.; Bartholomeus, R. P.; Bonfante, A.; de Lorenzi, F.; Dury, M.; Gloning, P.; Abou Jaoudé, R.; Klein, T.; Kuster, T. M.; Martins, M.; Niedrist, G.; Riccardi, M.; Wohlfahrt, G.; de Angelis, P.; de Dato, G.; François, L.; Menzel, A.; Pereira, M.

    2013-01-01

    We review observational, experimental and model results on how plants respond to extreme climatic conditions induced by changing climatic variability. Distinguishing between impacts of changing mean climatic conditions and changing climatic variability on terrestrial ecosystems is generally underrated in current studies. The goals of our review are thus (1) to identify plant processes that are vulnerable to changes in the variability of climatic variables rather than to changes in their mean, and (2) to depict/evaluate available study designs to quantify responses of plants to changing climatic variability. We find that phenology is largely affected by changing mean climate but also that impacts of climatic variability are much less studied but potentially damaging. We note that plant water relations seem to be very vulnerable to extremes driven by changes in temperature and precipitation and that heatwaves and flooding have stronger impacts on physiological processes than changing mean climate. Moreover, interacting phenological and physiological processes are likely to further complicate plant responses to changing climatic variability. Phenological and physiological processes and their interactions culminate in even more sophisticated responses to changing mean climate and climatic variability at the species and community level. Generally, observational studies are well suited to study plant responses to changing mean climate, but less suitable to gain a mechanistic understanding of plant responses to climatic variability. Experiments seem best suited to simulate extreme events. In models, temporal resolution and model structure are crucial to capture plant responses to changing climatic variability. We highlight that a combination of experimental, observational and /or modeling studies have the potential to overcome important caveats of the respective individual approaches. PMID:23504722

  9. Deciphering landscape complexity to predict (non)linear responses to extreme climatic events

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Extreme events are increasing in frequency and magnitude for many landscapes globally. Ecologically, most of the focus on extreme climatic events has been on effects of either short-term pulses (floods, freezes) or long-term drought. Multi-year increases in precipitation are also occurring with litt...

  10. Providing the Larger Climate Context During Extreme Weather - Lessons from Local Television News

    NASA Astrophysics Data System (ADS)

    Woods, M.; Cullen, H. M.

    2015-12-01

    Local television weathercasters, in their role as Station Scientists, are often called upon to educate viewers about the science and impacts of climate change. Climate Central supports these efforts through its Climate Matters program. Launched in 2010 with support from the National Science Foundation, the program has grown into a network that includes more than 245 weathercasters from across the country and provides localized information on climate and ready-to-use, broadcast quality graphics and analyses in both English and Spanish. This presentation will focus on discussing best practices for integrating climate science into the local weather forecast as well as advances in the science of extreme event attribution. The Chief Meteorologist at News10 (Sacramento, CA) will discuss local news coverage of the ongoing California drought, extreme weather and climate literacy.

  11. Climate Impact Reporter: A New Tool for Archiving and Displaying Climate-related Impacts to Extreme Events

    NASA Astrophysics Data System (ADS)

    Umphlett, N.; Shulski, M.; Lahowetz, J.; Sorensen, W.

    2014-12-01

    The High Plains Regional Climate Center (HPRCC) has been providing users with custom climate services for over 25 years. Stakeholder needs in the High Plains Region have evolved over time from simple data requests to inquiries about the impacts of various climate-related events. At this time, climate impacts may be reported in numerous locations such as newspapers, scholarly journals, and extension articles. In order to meet the increasing demand for climate impact information, HPRCC is beta-testing an online tool which synthesizes, archives, and displays impacts related to extreme climate events from multiple sources. The tool is intended to fulfill the needs of two general types of users - those who need a place to archive climate impact information and those seeking such information. As such, there are two main components to the tool: 1) a back-end interface where an impact information database is populated and 2) a front-end interface where users may browse the impacts. On the front-end, users can select an area (i.e. river basin, state, county warning area) and search for climate-related impacts within that area. Key impacts include the following sectors: agriculture, ecosystems, energy, human health, society, transportation, and water resources. In this regard, information can also be useful for future National Climate Assessment activities. Ultimately, an understanding of impacts to extreme events by sector will provide critical information for improved decision-making and adaptation strategies.

  12. Potential Impacts of Climate Change on Extreme Rainfall Events over Three Coastal Cities in Africa

    NASA Astrophysics Data System (ADS)

    Abiodun, Babatunde J.; Adegoke, Jimmy; Abatan, Abayomi

    2016-04-01

    This study examines the potential impacts of climate change on the characteristics extreme events over three coastal cities in Africa (Lagos, Cape Town and Cairo), with a focus on widespread extreme events (WERE) over the cities. An ensemble of regional climate model (RCA4) simulations, forced with CMIP5 (http://cmip-pcmdi.llnl.gov/cmip5) models under two climate scenarios (RCP 4.5 and RCP 8.5), were analyzed for the study. All the simulations were obtained from CORDEX (www.cordex.org). In this study, we used 95th percentile of daily rainfall as the threshold of extreme events and the simultaneous occurrence of extreme events over 50 % of the city area as widespread extreme events (WERE). The RCA ensemble gives a realistic simulation of seasonal and intra-seasonal variability of extreme rainfall events over the cities. The model ensemble projects an increase in the intensity and frequency of grid-point extreme rainfall events, but a decrease in the frequency of the WEREs over the cities in the future (2031 - 2065). The magnitudes of the changes are higher for RCP 8.5 than for RCP 4.5. The associated changes in the atmospheric circulations will be discussed at the conference. The result of this study has application in minimizing the vulnerabilities of these coastal cities to climate change impacts.

  13. Altered Acer Rubrum Fecundity Induced By Chemical Climate Change

    NASA Astrophysics Data System (ADS)

    Deforest, J. L.; Peters, A.

    2014-12-01

    Red maple (Acer rubrum L.) is becoming the most dominating tree in North American eastern deciduous forests. Concurrently, human activities have altered the chemical climate of terrestrial ecosystems via acidic deposition, which increases the available of nitrogen (N), while decreasing phosphorus (P) availability. Once a minor forest component prior to European settlement, the abundance of red maple may be a symptom of the modern age. The current paradigm explaining red maple's rise to prominence concerns fire suppression that excludes competitors. However, this still does not explain why red maple is unique compared to other functionally similar trees. The objective of this study was to investigate the interactive influence of acid rain mitigation on the fecundity of red maple. Objectives were achieved by measuring flowering, seed production, germination, and growth from red maple on plots that have been experimentally manipulated to increase soil pH, P, or both in three unglaciated eastern deciduous hardwood forests. At least 50% of the red maple population is seed bearing in our control soils, however the median percent of seed-bearing trees declined to zero when mitigating soils from acidic deposition. This can be explained by the curious fact that red maple is polygamodioecious, or has labile sex-expression, in which an individual tree can change its sex-expression in response to the environment. Furthermore, seed-bearing trees in the mitigated plots grew less, produced less seeds, and germinated at lower rates than their counterparts in control soils. Our results provide evidence that chemical climate change could be the primary contributing factor accelerating the dominance of red maple in eastern North American forests. Our observations can provide a boarder conceptual framework for understanding how nutrient limitations can be applied beyond plant productivity towards explaining distribution changes in vegetation.

  14. Life stage influences the resistance and resilience of black mangrove forests to winter climate extremes

    USGS Publications Warehouse

    Osland, Michael J.; Day, Richard H.; From, Andrew S.; McCoy, Megan L.; McLeod, Jennie L.; Kelleway, Jeffrey

    2015-01-01

    In subtropical coastal wetlands on multiple continents, climate change-induced reductions in the frequency and intensity of freezing temperatures are expected to lead to the expansion of woody plants (i.e., mangrove forests) at the expense of tidal grasslands (i.e., salt marshes). Since some ecosystem goods and services would be affected by mangrove range expansion, there is a need to better understand mangrove sensitivity to freezing temperatures as well as the implications of changing winter climate extremes for mangrove-salt marsh interactions. In this study, we investigated the following questions: (1) how does plant life stage (i.e., ontogeny) influence the resistance and resilience of black mangrove (Avicennia germinans) forests to freezing temperatures; and (2) how might differential life stage responses to freeze events affect the rate of mangrove expansion and salt marsh displacement due to climate change? To address these questions, we quantified freeze damage and recovery for different life stages (seedling, short tree, and tall tree) following extreme winter air temperature events that occurred near the northern range limit of A. germinans in North America. We found that life stage affects black mangrove forest resistance and resilience to winter climate extremes in a nonlinear fashion. Resistance to winter climate extremes was high for tall A. germinans trees and seedlings, but lowest for short trees. Resilience was highest for tall A. germinans trees. These results suggest the presence of positive feedbacks and indicate that climate-change induced decreases in the frequency and intensity of extreme minimum air temperatures could lead to a nonlinear increase in mangrove forest resistance and resilience. This feedback could accelerate future mangrove expansion and salt marsh loss at rates beyond what would be predicted from climate change alone. In general terms, our study highlights the importance of accounting for differential life stage responses and

  15. Identification of Climate Change with Generalized Extreme Value (GEV) Distribution Approach

    NASA Astrophysics Data System (ADS)

    Rahayu, Anita

    2013-04-01

    Some events are difficult to avoid and gives considerable influence to humans and the environment is extreme weather and climate change. Many of the problems that require knowledge about the behavior of extreme values and one of the methods used are the Extreme Value Theory (EVT). EVT used to draw up reliable systems in a variety of conditions, so as to minimize the risk of a major disaster. There are two methods for identifying extreme value, Block Maxima with Generalized Extreme Value (GEV) distribution approach and Peaks over Threshold (POT) with Generalized Pareto Distribution (GPD) approach. This research in Indramayu with January 1961-December 2003 period, the method used is Block Maxima with GEV distribution approach. The result showed that there is no climate change in Indramayu with January 1961-December 2003 period.

  16. Adapting to extreme climates: raising animals in hot and arid ecosystems in Australia.

    PubMed

    Seo, S Niggol

    2015-05-01

    This paper provides an analysis of adaptation to extreme climate changes using the Australian animal husbandry data. The paper finds that farmers have adapted to a hot and arid climate regime through animal husbandry. The number of sheep vastly increases into arid ecosystems while the number of beef cattle does not decline in high temperatures. In the future climate system in which Australia becomes hotter and more arid, we predict that farmers will increase by large percentages the numbers of beef cattle and/or sheep owned in order to adapt to a highly unfavorable climate condition, especially into the arid ecosystems. This paper shows how humanity has adapted to climate extremes taking into account changing ecosystems.

  17. Adapting to extreme climates: raising animals in hot and arid ecosystems in Australia

    NASA Astrophysics Data System (ADS)

    Seo, S. Niggol

    2015-05-01

    This paper provides an analysis of adaptation to extreme climate changes using the Australian animal husbandry data. The paper finds that farmers have adapted to a hot and arid climate regime through animal husbandry. The number of sheep vastly increases into arid ecosystems while the number of beef cattle does not decline in high temperatures. In the future climate system in which Australia becomes hotter and more arid, we predict that farmers will increase by large percentages the numbers of beef cattle and/or sheep owned in order to adapt to a highly unfavorable climate condition, especially into the arid ecosystems. This paper shows how humanity has adapted to climate extremes taking into account changing ecosystems.

  18. Multiple climate cooling prior to Sturtian glaciations: Evidence from chemical index of alteration of sediments in South China

    PubMed Central

    Huang, Jing; Feng, Lianjun; Lu, Dingbiao; Zhang, Qirui; Sun, Tao; Chu, Xuelei

    2014-01-01

    Investigation of climatic conditions prior to the Sturtian glaciations is critical to understanding the trigger mechanism for the series of Neoproterozoic global glaciations. In this study, we report high-resolution chemical index of alteration (CIA) records in the sediments of South China prior to the Sturtian glaciation (820~720 Ma). Our results showed there occurred multiple climate cooling before the Sturtian glaciations in South China: (1) a series of episodic and possibly global climate cooling periods from ca. 750 Ma to 725 Ma, which also caused some diachronous regional glaciations; (2) a permanent climate cooling period between ca. 800 Ma and 770 Ma, probably contemporaneous to the global “Bitter Springs stage” δ13C negative excursion; (3) a climate cooling period between ca. 815 Ma and 810 Ma. The three stages of climate cooling are also supported by their correspondence to previously reported extremely low δ18O records of igneous/metamorphic minerals from South China. These climate cooling periods also coincide with the magmatism and rifting events in South China. We argue that tectonic movements were the primary control on the climate cooling before the Neoproterozoic global glaciations. PMID:25359610

  19. Multiple climate cooling prior to Sturtian glaciations: Evidence from chemical index of alteration of sediments in South China

    NASA Astrophysics Data System (ADS)

    Huang, Jing; Feng, Lianjun; Lu, Dingbiao; Zhang, Qirui; Sun, Tao; Chu, Xuelei

    2014-10-01

    Investigation of climatic conditions prior to the Sturtian glaciations is critical to understanding the trigger mechanism for the series of Neoproterozoic global glaciations. In this study, we report high-resolution chemical index of alteration (CIA) records in the sediments of South China prior to the Sturtian glaciation (820~720 Ma). Our results showed there occurred multiple climate cooling before the Sturtian glaciations in South China: (1) a series of episodic and possibly global climate cooling periods from ca. 750 Ma to 725 Ma, which also caused some diachronous regional glaciations; (2) a permanent climate cooling period between ca. 800 Ma and 770 Ma, probably contemporaneous to the global ``Bitter Springs stage'' δ13C negative excursion; (3) a climate cooling period between ca. 815 Ma and 810 Ma. The three stages of climate cooling are also supported by their correspondence to previously reported extremely low δ18O records of igneous/metamorphic minerals from South China. These climate cooling periods also coincide with the magmatism and rifting events in South China. We argue that tectonic movements were the primary control on the climate cooling before the Neoproterozoic global glaciations.

  20. Effects of climate variability and extreme events on components of the carbon balance in Europe during 1961-2100

    NASA Astrophysics Data System (ADS)

    Beer, Christian; Carvalhais, Nuno; Ciais, Philippe; Balkovic, Juraj; Davin, Edouard; Kato, Tomomichi; Kuhnert, Matthias; Lardy, Romain; Laperche, Sylvain; Martin, Raphaël; van Oijen, Marcel; Rammig, Anja; Rolinski, Susanne; Seneviratne, Sonia; Smith, Pete; Thonicke, Kirsten; van der Velde, Marijn; Vieli, Barla; Viovy, Nicolas; Reichstein, Markus

    2013-04-01

    Regional climate models project a change in the annual and seasonal mean of meteorological variables in Europe until the end of the century, e. g. mean air temperature is predicted to dramatically increase until 2100. At the same time, the shape of the probability distribution of meteorological variables will change, leading to an altered variability of meteorological variables and frequency of extreme events. Today, the isolated effects of changing variance versus changing mean of meteorological drivers on ecosystem processes, such as gross primary production, autotrophic and heterotrophic respiration, evapotranspiration, mortality and disturbances have not been quantified at a continental or global scale. We contribute to such quantification from a theoretical, mechanistic modelling point of view by artificial modelling experiments using state-of-the-art generic (LPJmL, ORCHIDEE, JSBACH, CLM) and sectorial (BASFOR, DailyDayCent, PASIM) ecosystem models that has been performed in the EU FP7 project CARBO-Extreme. Using a control climate data set (CNTL) based on the WATCH forcing data and bias-corrected ECMWF ERA-Interim reanalysis data, factorial model experiments with transient/constant climate and atmospheric [CO2] concentration have been performed.Then, these factorial experiments were repeated using a climate dataset in which climate variables hold the same long-term seasonal and annual mean but show much reduced short-term variability ("reduced variability"). Analysis of the resulting carbon and water balance estimations for Europe during 1961-2100 enabled disentangling direct effects of temperature or radiation variability from effects of general climate variability and effects of a trend in mean climate conditions on ecosystem functions. Generally, reduced variability in short-wave radiation increased the annual gross primary production due to the concave shape of the light response curve of photosynthesis. Therefore, net primary production is also

  1. Global impacts of hydrological and climatic extremes on vegetation (SAT-EX)

    NASA Astrophysics Data System (ADS)

    Depoorter, M.; Waegeman, W.; Verhoest, N.; Regnier, P.; Friedlingstein, P.; Dolman, A. J.; de Jeu, R.; Dorigo, W.; Miralles, D. G.

    2014-12-01

    Global warming is expected to increase the frequency and severity of droughts, extreme precipitation events and heatwaves. Recent studies have underlined the critical impacts of these extremes on the terrestrial carbon cycle, particularly on the dynamics of vegetation. Yet, the latest IPCC report reveals large uncertainties in extremes trends and biomass impacts. Conversely, new advances in satellite Earth observation have led to the recent development of consistent global historical records of crucial environmental and climatic variables - like surface soil moisture, soil water storage, terrestrial evaporation or vegetation water content. These datasets provide alternative means to unravel the processes driving past climate extremes, uncover the spatiotemporal scales at which these extremes operate and understand their impact on terrestrial biomass. The SAT-EX project (funded by BELSPO) recently raised with the purpose of exploring the potential of the state-of-art remote sensing datasets to study the causes and consequences of the spatiotemporal changes in wet, dry and warm spells over the past three decades. Core methodologies involve the analysis of satellite-based climate extreme indices and vegetation characteristics through a novel combination of machine learning methods and fingerprint identification approaches. First results will show how droughts, heatwaves and extreme rain events have changed in frequency and intensity since the '80s, and attribute these changes to on-going processes like the widening of the tropical belt, ocean-atmospheric teleconnections, the intensification of land-atmospheric feedbacks or the overall rise in greenhouse gasses (and expected acceleration of the hydrological cycle). At the same time, our analyses will uncover the effects of climate extremes on large-scale vegetation dynamics. Further phases in the project will involve the evaluation of IPCC Earth System Models on the basis of their skill to reproduce the effects of

  2. Global impacts of hydrological and climatic extremes on vegetation (SAT-EX)

    NASA Astrophysics Data System (ADS)

    van Eck, Christel Melissa; Waegeman, Willem; Papagiannopoulou, Christina; Verhoest, Niko; Depoorter, Mathieu; Regnier, Pierre; Friedlingstein, Pierre; Dolman, A. Johannes; de Jeu, Richard; Dorigo, Wouter; Miralles, Diego G.

    2015-04-01

    Global warming is expected to increase the frequency and severity of droughts, extreme precipitation events and heatwaves. Recent studies have underlined the critical impacts of these extremes on the terrestrial carbon cycle, particularly on the dynamics of vegetation. Yet, the latest IPCC report reveals large uncertainties in extremes trends and biomass impacts. Conversely, new advances in satellite Earth observation have led to the recent development of consistent global historical records of crucial environmental and climatic variables - like surface soil moisture, soil water storage, terrestrial evaporation or vegetation water content. These datasets provide alternative means to unravel the processes driving past climate extremes, uncover the spatiotemporal scales at which these extremes operate and understand their impact on terrestrial biomass. The SAT-EX project (funded by BELSPO) recently raised with the purpose of exploring the potential of the state-of-art remote sensing datasets to study the causes and consequences of the spatiotemporal changes in wet, dry and warm spells over the past three decades. Core methodologies involve the analysis of satellite-based climate extreme indices and vegetation characteristics through a novel combination of machine learning methods, fingerprint identification approaches, and spatio-temporal clustering. First results will show how droughts, heatwaves and extreme rain events have changed in frequency and intensity since the '80s, and attribute these changes to on-going processes like the widening of the tropical belt, ocean-atmospheric teleconnections, the intensification of land-atmospheric feedbacks or the overall rise in greenhouse gasses (and expected acceleration of the hydrological cycle). A specific focus will be given on large-scale vegetation response to climate extremes throughout our analyses. Further phases in the project will involve the evaluation of IPCC Earth System Models on the basis of their skill to

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

    NASA Astrophysics Data System (ADS)

    Zarekarizi, Mahkameh; Rana, Arun; Moradkhani, Hamid

    2016-04-01

    Recently research has focused on the influence of climate indices on precipitation extremes. In the current study, we present the analysis of the precipitation-based extremes in Columbia River Basin (CRB) in the Pacific North-West USA. We first analyzed the precipitation-based extreme indices using statistically downscaled past and future climate projections from ten GCMs. Seven different precipitation-based indices that help inform about the flood duration/intensity are used in the study. These indices would give firsthand information on spatial and temporal scales for different service sectors including energy, agriculture, forestry etc. in the area. Temporally, historical and future projections are analyzed over the whole CRB using ten CMIP5 models. For each scenario, we have mapped out these indices over the area to see the spatial variation of past and future extremes. The analysis shows that high values of extreme indices are clustered in either western or southern parts of the basin while northern part of the basin is experiencing high increase in the indices in future scenarios. Here we focus our attention on evaluating the relation of these extreme and climate indices in historical period to understand which climate indices have more impact on extremes over CRB. Various climate indices are evaluated for their relationship using Principal Component Analysis (PCA) and Singular Value Decomposition (SVD). Results indicated that, out of fifteen climate indices used in the study, CRB is being most affected negatively by East Pacific (EP), Western Pacific Index (WP), Eastern Asia (EA) and North Atlantic Oscillation (NAO).

  4. The link between convective organization and extreme precipitation in a warming climate

    NASA Astrophysics Data System (ADS)

    Pendergrass, Angeline

    2016-04-01

    The rate of increase of extreme precipitation in response to global warming varies dramatically across simulations of warming with different climate models, particularly over the tropical oceans, for reasons that have yet to be established. Here, we propose one possible mechanism: changing organization of convection with climate. Recently, self-organization of convection has been studied in global radiative-convective equilibrium climate model simulations. We analyze a set of 20 simulations forced by fixed SSTs at 2 degree increments from 287 to 307 K with the Community Atmosphere Model version 5 (CAM5). In these simulations, a transition from unorganized to organized convection occurs at just over 300 K. Precipitation extremes increase steadily with warming before and after the transition from unorganized to organized states, but at the transition the change in extreme precipitation is much larger. We develop a metric for convective organization in conjunction with the characteristics of extreme precipitation events (defined as events with precipitation over a percentile threshold of daily rainfall accumulation): the number of events, their area, their lifetime, and their mean rainfall, and use this to explore the connection between extreme precipitation and organization. We also apply this metric to CMIP5 simulations to evaluate whether our mechanism has bearing on the range of tropical ocean extreme precipitation response across this set of comprehensive climate models.

  5. Exposure and Figure Out of Climate Induced Alterations in the Wetlands of Banglades

    NASA Astrophysics Data System (ADS)

    Siddiquee, S. A.; Rahman, M. Z.

    2015-12-01

    Unique geographic location and geo-morphological conditions of Bangladesh have made the wetlands of this country one of the most vulnerable to climate change. Wetland plays a crucial role in maintaining the ecological balance of ecosystems and cultural figures and which occupy around 50% of the area. Drought, excessive temperature, mountain snowfields and glaciers melting, riverbank erosion, salinity intrusion, flashflood, storm surges, higher water temperatures, precipitation anomalies, coastal cyclones, seasonal anomalies and extremes are main threats to the wetland ecosystem. Enhanced UV-B radiation and increased summer precipitation will significantly increase dissolved organic carbon concentrations altering major biogeochemical cycles and also will result into the expansion of range for many invasive aquatic weeds. Generally, rising temperature will lower water quality through a fall in oxygen concentrations, release of phosphorus from sediments, increased thermal stability, and altered mixing patterns. As a result biodiversity is getting degraded, many species of flora and fauna are getting threatened, and wetland-based ecosystem is getting degenerated. At the same time, the living conditions of local people are deteriorating as livelihoods, socioeconomic institutions, and extensive cultural values as well. For conserving and managing wetlands technology, legislation, educational knowledge, action plan strategy and restoration practices are required. In order to address the human needs in the changing climate community-based adaptation approaches and wetland restoration, practices had been taken in almost every type of wetlands in Bangladesh. Therefore, Bangladesh now needs a comprehensive strategy and integrated system combining political, economic, social, technological approaches and institutional supports to address sustainable wetland restoration, conservation and the newly added crisis, climate change.

  6. Multimodel ensemble projections of future climate extreme changes in the Haihe River Basin, China

    NASA Astrophysics Data System (ADS)

    Wang, Weiguang; Shao, Quanxi; Yang, Tao; Yu, Zhongbo; Xing, Wanqiu; Zhao, Cuiping

    2014-11-01

    Exploring the characteristic of the extreme climatic events, especially future projection is considerably important in assessing the impacts of climatic change on hydrology and water resources system. We investigate the future patterns of climate extremes (2001-2099) in the Haihe River Basin (HRB) derived from Coupled General Circulation Model (CGCM) multimodel ensemble projections using the Bayesian Model Average (BMA) approach, under a range of emission scenarios. The extremes are depicted by three extreme temperature indices (i.e., frost days (FD), growing season length (GSL), and T min >90th percentile (TN90)) and five extreme precipitation indices (i.e., consecutive dry days (CDD), precipitation ≥10 mm (R10), maximum 5-day precipitation total (R5D), precipitation >95th percentile (R95T), and simple daily intensity index (SDII)). The results indicate frost days display negative trend over the HRB in the 21st century, particularly in the southern basin. Moreover, a greater season length and more frequent warm nights are also projected in the basin. The decreasing CDD, together with the increasing R10, R5D, R95T, and SDII in the 21st century indicate that the extreme precipitation events will increase in their intensity and frequency in the basin. Meanwhile, the changes of all eight extremes climate indices under A2 and A1B scenarios are more pronounced than in B1. The results will be of practical significance in mitigation of the detrimental effects of variations of climatic extremes and improve the regional strategy for water resource and eco-environment management, particularly for the HRB characterized by the severe water shortages and fragile ecological environment.

  7. Climate change effects on extreme flows of water supply area in Istanbul: utility of regional climate models and downscaling method.

    PubMed

    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. Hydrologic regime alteration of a Mediterranean catchment under climate change projection

    NASA Astrophysics Data System (ADS)

    Sellami, Haykel; Benabdallah, Sihem; La Jeunesse, Isabelle; Herrmann, Frank; Vanclooster, Marnik

    2014-05-01

    Most of the climate models projections for the Mediterranean basin have showed that the region will likely to experience a general tendency towards drier climate conditions with decreases in total precipitation, increases in temperature, alterations in the rainfall extreme events and droughts frequency (IPCC, 2007; Giorgi and Lionello, 2008; López-Moreno et al., 2011). The region is already suffering from water resources scarcity and vulnerability which are expected to amplify in the next century (Ludwig et al., 2011; Schneider et al., 2013). Therefore, assessing the impact of climate change on the hydrologic regime of Mediterranean catchments is with a major concern not only to scientist but also to water resources policy makers and general public. However, most of the climate change impact studies focus on the flow regime on global or regional scale rather than on the catchment scale which is more useful and more appropriate to guide practical mitigation and adaptation policy. This is because hydro-climate modeling at the local scale is confronted to the variability in climate, topography, geology, lack of observations and anthropogenic activities within the catchment. Furthermore, it is well recognized that hydrological and climate models forecasts are always affected with uncertainty making the assessment of climate change impact on Mediterranean catchment hydrology more challenging. This work aims to assess the impact of climate change on a Mediterranean catchment located in North Africa (the Chiba catchment in northeast Tunisia) through a conjunctive use of physically based hydrological model (SWAT) driven with four climate models*. Quantification of the impact of climate change has been conducted by means of the Indicators of Hydrologic Alteration (Richter et al., 1996) which are also ecologically meaningful. By comparing changes in these indicators in the reference period (1971-2000) to the projected ones in the future (2041-2070), it was possible to draw

  9. Interannual to millennial variability of climate extreme indices over Europe: evidence from high resolution proxy data

    NASA Astrophysics Data System (ADS)

    Rimbu, Norel; Ionita, Monica; Lohmann, Gerrit

    2016-04-01

    Interannual to millennial time scale variability of precipitation (R20mm, Rx5day, R95pTOT), cold (TN10p, CSDI and CFD), heat (TX90p and WSDI) and drought (CDD) extreme climate indices is investigated using long-term observational and proxy records. We detect significant correlations between these indices and various high resolution proxy records like lake sediments from southern Germany, stable oxygen isotopes from Greenland ice cores and stable oxygen isotopes from Red Sea corals during observational period. The analysis of long-term reanalysis data in combination with extreme climate indices and proxy data reveals that distinct atmospheric circulation patterns explain most of the identified relationships. In particular, we show that a sediment record from southern Germany (lake Ammersee), which records flood frequency of River Ammer during the last 5500 years, is related to a wave-train atmospheric circulation pattern with a pronounced negative center over western Europe. We show that high frequency of River Ammer floods is related not only to high frequency of extreme precipitation events (R95p) in the Ammer region but also with significant positive anomalies of various extreme temperature indices (TX90p and TXx) over northeastern Europe. Such extreme temperatures are forced by cloudiness anomaly pattern associated with flood related atmospheric circulation pattern. Based on this record we discuss possible interannual to millennial scale variations of extreme precipitation and temperature indices over Europe during the last 5500 years. Coherent variations of extreme precipitation and temperature indices over Europe and stable oxygen isotopes from Greenland ice cores and northern Red Sea corals during observational period are related to atmospheric blocking variability in the North Atlantic region. Possible variations of climate extreme indices during different time slices of the Holocene period and their implications for future extreme climate variability are

  10. Influence of climate variability versus change at multi-decadal time scales on hydrological extremes

    NASA Astrophysics Data System (ADS)

    Willems, Patrick

    2014-05-01

    Recent studies have shown that rainfall and hydrological extremes do not randomly occur in time, but are subject to multidecadal oscillations. In addition to these oscillations, there are temporal trends due to climate change. Design statistics, such as intensity-duration-frequency (IDF) for extreme rainfall or flow-duration-frequency (QDF) relationships, are affected by both types of temporal changes (short term and long term). This presentation discusses these changes, how they influence water engineering design and decision making, and how this influence can be assessed and taken into account in practice. The multidecadal oscillations in rainfall and hydrological extremes were studied based on a technique for the identification and analysis of changes in extreme quantiles. The statistical significance of the oscillations was evaluated by means of a non-parametric bootstrapping method. Oscillations in large scale atmospheric circulation were identified as the main drivers for the temporal oscillations in rainfall and hydrological extremes. They also explain why spatial phase shifts (e.g. north-south variations in Europe) exist between the oscillation highs and lows. Next to the multidecadal climate oscillations, several stations show trends during the most recent decades, which may be attributed to climate change as a result of anthropogenic global warming. Such attribution to anthropogenic global warming is, however, uncertain. It can be done based on simulation results with climate models, but it is shown that the climate model results are too uncertain to enable a clear attribution. Water engineering design statistics, such as extreme rainfall IDF or peak or low flow QDF statistics, obviously are influenced by these temporal variations (oscillations, trends). It is shown in the paper, based on the Brussels 10-minutes rainfall data, that rainfall design values may be about 20% biased or different when based on short rainfall series of 10 to 15 years length, and

  11. Extreme climate event trends: The data mining and evaluation of the A1FI scenario for 2000-2100

    NASA Astrophysics Data System (ADS)

    Erickson, D. J.; Ganguly, A.; Steinhaeuser, K.; Branstetter, M.; Oglesby, R.; Hoffman, F.; Buja, L.

    2008-12-01

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

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

    SciTech Connect

    Erickson III, David J; Ganguly, Auroop R; Steinhaeuser, Karsten J K; Branstetter, Marcia L; Oglesby, Robert; Hoffman, Forrest M; Buja, Lawrence

    2008-01-01

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

  13. Global warming and changes in risk of concurrent climate extremes: Insights from the 2014 California drought

    NASA Astrophysics Data System (ADS)

    AghaKouchak, Amir; Cheng, Linyin; Mazdiyasni, Omid; Farahmand, Alireza

    2014-12-01

    Global warming and the associated rise in extreme temperatures substantially increase the chance of concurrent droughts and heat waves. The 2014 California drought is an archetype of an event characterized by not only low precipitation but also extreme high temperatures. From the raging wildfires, to record low storage levels and snowpack conditions, the impacts of this event can be felt throughout California. Wintertime water shortages worry decision-makers the most because it is the season to build up water supplies for the rest of the year. Here we show that the traditional univariate risk assessment methods based on precipitation condition may substantially underestimate the risk of extreme events such as the 2014 California drought because of ignoring the effects of temperature. We argue that a multivariate viewpoint is necessary for assessing risk of extreme events, especially in a warming climate. This study discusses a methodology for assessing the risk of concurrent extremes such as droughts and extreme temperatures.

  14. Do climate extreme events foster violent civil conflicts? A coincidence analysis

    NASA Astrophysics Data System (ADS)

    Schleussner, Carl-Friedrich; Donges, Jonathan F.; Donner, Reik V.

    2014-05-01

    Civil conflicts promoted by adverse environmental conditions represent one of the most important potential feedbacks in the global socio-environmental nexus. While the role of climate extremes as a triggering factor is often discussed, no consensus is yet reached about the cause-and-effect relation in the observed data record. Here we present results of a rigorous statistical coincidence analysis based on the Munich Re Inc. extreme events database and the Uppsala conflict data program. We report evidence for statistically significant synchronicity between climate extremes with high economic impact and violent conflicts for various regions, although no coherent global signal emerges from our analysis. Our results indicate the importance of regional vulnerability and might aid to identify hot-spot regions for potential climate-triggered violent social conflicts.

  15. Changing Climate Extremes in the Northeast: CMIP5 Simulations and Projections

    NASA Astrophysics Data System (ADS)

    Thibeault, J. M.; Seth, A.

    2013-12-01

    Extreme climate events are known to have severe impacts on human and natural systems. As greenhouse warming progresses, a major concern is the potential for an increase in the frequency and intensity of extreme events. The Northeast (defined as the Northeast US, southern Quebec, and southeastern Ontario) is sensitive to climate extremes. The region is prone to flooding and drought, which poses challenges for infrastructure and water resource management, and increases risks to agriculture and forests. Extreme heat can be dangerous to human health, especially in the large urban centers of the Northeast. Annual average temperatures have steadily increased since the 1970s, accompanied by more frequent extremely hot weather, a longer growing season, and fewer frost days. Heavy precipitation events have become more frequent in recent decades. This research examines multi-model projections of annual and monthly extreme indices for the Northeast, using extreme indices computed by the Expert Team on Climate Change Detection and Indices (ETCCDI) for twenty-three global climate models participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5) for the 20th century historical and RCP8.5 experiments. Model simulations are compared to HadEX2 and ERA-interim gridded observations. CMIP5 simulations are consistent with observations - conditions in the Northeast are already becoming warmer and wetter. Projections indicate significant shifts toward warmer and wetter conditions by the middle century (2041-2070). Most indices are projected to be largely outside their late 20th century ranges by the late century (2071-2099). These results provide important information to stakeholders developing plans to lessen the adverse impacts of a warmer and wetter climate in the Northeast.

  16. Vulnerability and resilience of European ecosystems towards extreme climatic events: The ecosystem perspective

    NASA Astrophysics Data System (ADS)

    Thonicke, Kirsten; Rolinski, Susanne; Walz, Ariane; von Bloh, Werner; van Oijen, Marcel; Davin, Edouard; Vieli, Barla; Kato, Tomomichi; Beer, Christian

    2014-05-01

    Extremes of meteorological events may but do not have to cause damages in ecosystems. Climate change is expected to have a strong impact on the resilience and stability of ecosystems worldwide. So far, the impacts of trends and extremes of physical drivers on ecosystems have generally been studied regardless of the extremeness of the ecosystem response. We base our analysis on a Probabilistic Risk Assessment concept of Van Oijen et al. (2013) quantifying the vulnerability of vegetation dynamics in relation to the extremeness of meteorological drivers such as temperature, precipitation or drought indices. Here, the definition of extreme, hazardous weather conditions is based on the ecosystem response. Instead of searching for extreme meteorological events, we define extreme ecosystem responses in terms of threshold levels of carbon uptake, and search for the meteorological conditions which are responsible. Having defined hazardous events in this way, we quantify the vulnerability or resilience of ecosystems to such hazards. We apply this approach on results of different vegetation models (such as LPJmL, Orchidee, JSBACH or CLM4) and the forest model BASFOR using climatic input for Europe from the WATCH-ERAI-REMO climate dataset with the SRES A1B emission scenario. Our results show that under current climatic conditions, the southern part of Europe already suffers severe heat and drought stress which is reflected in our approach by vulnerability values being high for precipitation, relatively high for the SPEI index, moderately high for temperature and quite high for the consecutive dry days. Thus, hazard occurrence is frequent enough to determine ecosystem vulnerability but this depends on the definition of the threshold of hazardous ecosystem responses. Vulnerability values in the Mediterranean increase towards the end of the 21st century for all models indicating that a tipping point towards drought damages has been reached for the chosen climate scenario.

  17. Quantifying the influence of observed global warming on the probability of unprecedented extreme climate events

    NASA Astrophysics Data System (ADS)

    Diffenbaugh, N. S.; Rajaratnam, B.; Charland, A.; Haugen, M.; Horton, D. E.; Singh, D.; Swain, D. L.; Tsiang, M.

    2014-12-01

    Now that observed global warming has been clearly attributed to human activities, there has been increasing interest in the extent to which that warming has influenced the occurrence and severity of individual extreme climate events. However, although trends in the extremes of the seasonal- and daily-scale distributions of climate records have been analyzed for many years, quantifying the contribution of observed global warming to individual events that are unprecedented in the observed record presents a particular scientific challenge. We will describe a modified method for leveraging observations and large climate model ensembles to quantify the influence of observed global warming on the probability of unprecedented extreme events. In this approach, we first diagnose the causes of the individual event in order to understand which climate processes to target in the probability quantification. We then use advanced statistical techniques to quantify the uncertainty in the return period of the event in the observed record. We then use large ensembles of climate model simulations to quantify the distribution of return period ratios between the current level of climate forcing and the pre-industrial climate forcing. We will compare the structure of this approach to other approaches that exist in the literature. We will then examine a set of individual extreme events that have been analyzed in the literature, and compare the results of our approach with those that have been previously published. We will conclude with a discussion of the observed agreement and disagreement between the different approaches, including implications for interpretation of the role of human forcing in shaping unprecedented extreme events.

  18. Web-based Visual Analytics for Extreme Scale Climate Science

    SciTech Connect

    Steed, Chad A; Evans, Katherine J; Harney, John F; Jewell, Brian C; Shipman, Galen M; Smith, Brian E; Thornton, Peter E; Williams, Dean N.

    2014-01-01

    In this paper, we introduce a Web-based visual analytics framework for democratizing advanced visualization and analysis capabilities pertinent to large-scale earth system simulations. We address significant limitations of present climate data analysis tools such as tightly coupled dependencies, ineffi- cient data movements, complex user interfaces, and static visualizations. Our Web-based visual analytics framework removes critical barriers to the widespread accessibility and adoption of advanced scientific techniques. Using distributed connections to back-end diagnostics, we minimize data movements and leverage HPC platforms. We also mitigate system dependency issues by employing a RESTful interface. Our framework embraces the visual analytics paradigm via new visual navigation techniques for hierarchical parameter spaces, multi-scale representations, and interactive spatio-temporal data mining methods that retain details. Although generalizable to other science domains, the current work focuses on improving exploratory analysis of large-scale Community Land Model (CLM) and Community Atmosphere Model (CAM) simulations.

  19. Climate Change Impacts on US Precipitation Extremes and Consequences for Hydraulic Infrastructures and Water Resources

    NASA Astrophysics Data System (ADS)

    Pal, S.; Kumar, D.; Mishra, V.; Ganguly, A. R.

    2013-12-01

    Precipitation extremes in the conterminous United States are expected to intensify and grow more frequent with climate change. However, translating this climate insight to metrics relevant for hydraulic infrastructures or water resources remains a challenge. The primary issue is one of scale, which in turn may ultimately stem from the space-time variability in, and our lack of understanding of, fine-scale precipitation processes. Here we examine the hypothesis that credible metrics for civil engineers and hydrologists can be obtained through extreme value analysis of regional climate model simulations. Specifically, we develop intensity-duration-frequency (IDF) curves from the North American Regional Climate Change Assessment Program (NARCCAP) simulations, and characterize uncertainties by comparing with observations. We attempt to understand the nature of the insights, if any, that can be extracted despite the uncertainties.

  20. The immediate and prolonged effects of climate extremes on soil respiration in a mesic grassland

    NASA Astrophysics Data System (ADS)

    Hoover, David L.; Knapp, Alan K.; Smith, Melinda D.

    2016-04-01

    The predicted increase in the frequency and intensity of climate extremes is expected to impact terrestrial carbon fluxes to the atmosphere, potentially changing ecosystems from carbon sinks to sources, with positive feedbacks to climate change. As the second largest terrestrial carbon flux, soil CO2 efflux or soil respiration (Rs) is strongly influenced by soil temperature and moisture. Thus, climate extremes such as heat waves and extreme drought should have substantial impacts on Rs. We investigated the effects of such climate extremes on growing season Rs in a mesic grassland by experimentally imposing 2 years of extreme drought combined with midsummer heat waves. After this 2 year period, we continued to measure Rs during a recovery year. Two consecutive drought years reduced Rs by about 25% each growing season; however, when normal rainfall returned during the recovery year, formerly droughted plots had higher rates of Rs than control plots (up to +17%). The heat wave treatments had no effect on Rs, alone or when combined with drought, and during the growing season, soil moisture was the primary driver of Rs with little evidence for Rs temperature sensitivity. When compared to aboveground net primary production, growing season Rs was much less sensitive to drought but was more responsive postdrought. These results are consistent with the hypothesis that ecosystems become sources of CO2 during drought because carbon inputs (production) are decreased relatively more than outputs (respiration). Moreover, stimulation of Rs postdrought may lengthen the time required for net carbon exchange to return to predrought levels.

  1. Climate change impacts on hydrological extremes (floods, low flows) along catchments in the Scheldt river basin

    NASA Astrophysics Data System (ADS)

    Ntegeka, Victor; Willems, Patrick; Baguis, Pierre; Roulin, Emmanuel; Vansteenkiste, Thomas; Holvoet, Katijn

    2010-05-01

    The potential climate change impacts on hydrological extremes (floods and low flows) have been investigated for rivers in highly urbanized catchments in the Scheldt river basin in Belgium. Results of 31 simulations with 11 Regional Climate Models (RCMs) from the EU PRUDENCE project were statistically analyzed for both the control period 1961-1990 and the scenario period 2071-2100. The more recent ENSEMBLES RCMs were not included because a cursory analysis showed somewhat higher biases for rainfall which was consistent with other detailed findings. The PRUDENCE RCM simulations were transformed into tailored climate change scenarios for rainfall and potential evapotranspiration to facilitate the hydrological impact study. The hydrological impacts were investigated by means of combined hydrological-hydraulic models; both lumped conceptual models, and spatially distributed and detailed physically-based models were considered. The performance of these models in predicting extreme high and low flow statistics has been validated through hydrological time series techniques and statistical extreme value analysis. Given that the hydrological model uncertainty is less than the climate model uncertainty, it was found necessary to apply an ensemble of climate models. The accuracy of the RCM simulations in describing rainfall extremes was assessed for the control period using frequency analysis techniques. The range of projected changes in the daily extremes and the range of projected changes in the number of wet days for rainfall were statistically downscaled (to the hourly time scale) using a quantile perturbation method. The quantile perturbation method is a variant of the quantile mapping technique commonly applied in climate modeling for bias removal. The method essentially extracts the quantile perturbations from the high resolution RCMs and then applies the perturbations to observed series. The use of quantile perturbations is particularly relevant for reflecting the

  2. Extreme Events in China under Climate Change: Uncertainty and related impacts (CSSP-FOREX)

    NASA Astrophysics Data System (ADS)

    Leckebusch, Gregor C.; Befort, Daniel J.; Hodges, Kevin I.

    2016-04-01

    Suitable adaptation strategies or the timely initiation of related mitigation efforts in East Asia will strongly depend on robust and comprehensive information about future near-term as well as long-term potential changes in the climate system. Therefore, understanding the driving mechanisms associated with the East Asian climate is of major importance. The FOREX project (Fostering Regional Decision Making by the Assessment of Uncertainties of Future Regional Extremes and their Linkage to Global Climate System Variability for China and East Asia) focuses on the investigation of extreme wind and rainfall related events over Eastern Asia and their possible future changes. Here, analyses focus on the link between local extreme events and their driving weather systems. This includes the coupling between local rainfall extremes and tropical cyclones, the Meiyu frontal system, extra-tropical teleconnections and monsoonal activity. Furthermore, the relation between these driving weather systems and large-scale variability modes, e.g. NAO, PDO, ENSO is analysed. Thus, beside analysing future changes of local extreme events, the temporal variability of their driving weather systems and related large-scale variability modes will be assessed in current CMIP5 global model simulations to obtain more robust results. Beyond an overview of FOREX itself, first results regarding the link between local extremes and their steering weather systems based on observational and reanalysis data are shown. Special focus is laid on the contribution of monsoonal activity, tropical cyclones and the Meiyu frontal system on the inter-annual variability of the East Asian summer rainfall.

  3. Attributing human mortality during extreme heat waves to anthropogenic climate change

    NASA Astrophysics Data System (ADS)

    Mitchell, Daniel; Heaviside, Clare; Vardoulakis, Sotiris; Huntingford, Chris; Masato, Giacomo; Guillod, Benoit P.; Frumhoff, Peter; Bowery, Andy; Wallom, David; Allen, Myles

    2016-07-01

    It has been argued that climate change is the biggest global health threat of the 21st century. The extreme high temperatures of the summer of 2003 were associated with up to seventy thousand excess deaths across Europe. Previous studies have attributed the meteorological event to the human influence on climate, or examined the role of heat waves on human health. Here, for the first time, we explicitly quantify the role of human activity on climate and heat-related mortality in an event attribution framework, analysing both the Europe-wide temperature response in 2003, and localised responses over London and Paris. Using publicly-donated computing, we perform many thousands of climate simulations of a high-resolution regional climate model. This allows generation of a comprehensive statistical description of the 2003 event and the role of human influence within it, using the results as input to a health impact assessment model of human mortality. We find large-scale dynamical modes of atmospheric variability remain largely unchanged under anthropogenic climate change, and hence the direct thermodynamical response is mainly responsible for the increased mortality. In summer 2003, anthropogenic climate change increased the risk of heat-related mortality in Central Paris by ∼70% and by ∼20% in London, which experienced lower extreme heat. Out of the estimated ∼315 and ∼735 summer deaths attributed to the heatwave event in Greater London and Central Paris, respectively, 64 (±3) deaths were attributable to anthropogenic climate change in London, and 506 (±51) in Paris. Such an ability to robustly attribute specific damages to anthropogenic drivers of increased extreme heat can inform societal responses to, and responsibilities for, climate change.

  4. Areas of potential suitability and survival of Dendroctonus valens in China under extreme climate warming scenario.

    PubMed

    He, S Y; Ge, X Z; Wang, T; Wen, J B; Zong, S X

    2015-08-01

    The areas in China with climates suitable for the potential distribution of the pest species red turpentine beetle (RTB) Dendroctonus valens LeConte (Coleoptera: Scolytidae) were predicted by CLIMEX based on historical climate data and future climate data with warming estimated. The model used a historical climate data set (1971-2000) and a simulated climate data set (2010-2039) provided by the Tyndall Centre for Climate Change (TYN SC 2.0). Based on the historical climate data, a wide area was available in China with a suitable climate for the beetle in which every province might contain suitable habitats for this pest, particularly all of the southern provinces. The northern limit of the distribution of the beetle was predicted to reach Yakeshi and Elunchun in Inner Mongolia, and the western boundary would reach to Keerkezi in Xinjiang Province. Based on a global-warming scenario, the area with a potential climate suited to RTB in the next 30 years (2010-2039) may extend further to the northeast. The northern limit of the distribution could reach most parts of south Heilongjiang Province, whereas the western limit would remain unchanged. Combined with the tendency for RTB to spread, the variation in suitable habitats within the scenario of extreme climate warming and the multiple geographical elements of China led us to assume that, within the next 30 years, RTB would spread towards the northeast, northwest, and central regions of China and could be a potentially serious problem for the forests of China.

  5. Local impact analysis of climate change on precipitation extremes: are high-resolution climate models needed for realistic simulations?

    NASA Astrophysics Data System (ADS)

    Tabari, Hossein; De Troch, Rozemien; Giot, Olivier; Hamdi, Rafiq; Termonia, Piet; Saeed, Sajjad; Brisson, Erwan; Van Lipzig, Nicole; Willems, Patrick

    2016-09-01

    This study explores whether climate models with higher spatial resolutions provide higher accuracy for precipitation simulations and/or different climate change signals. The outputs from two convection-permitting climate models (ALARO and CCLM) with a spatial resolution of 3-4 km are compared with those from the coarse-scale driving models or reanalysis data for simulating/projecting daily and sub-daily precipitation quantiles. Validation of historical design precipitation statistics derived from intensity-duration-frequency (IDF) curves shows a better match of the convection-permitting model results with the observations-based IDF statistics compared to the driving GCMs and reanalysis data. This is the case for simulation of local sub-daily precipitation extremes during the summer season, while the convection-permitting models do not appear to bring added value to simulation of daily precipitation extremes. Results moreover indicate that one has to be careful in assuming spatial-scale independency of climate change signals for the delta change downscaling method, as high-resolution models may show larger changes in extreme precipitation. These larger changes appear to be dependent on the timescale, since such intensification is not observed for daily timescales for both the ALARO and CCLM models.

  6. Analysis of the Impact of Climate Change on Extreme Hydrological Events in California

    NASA Astrophysics Data System (ADS)

    Ashraf Vaghefi, Saeid; Abbaspour, Karim C.

    2016-04-01

    Estimating magnitude and occurrence frequency of extreme hydrological events is required for taking preventive remedial actions against the impact of climate change on the management of water resources. Examples include: characterization of extreme rainfall events to predict urban runoff, determination of river flows, and the likely severity of drought events during the design life of a water project. In recent years California has experienced its most severe drought in recorded history, causing water stress, economic loss, and an increase in wildfires. In this paper we describe development of a Climate Change Toolkit (CCT) and demonstrate its use in the analysis of dry and wet periods in California for the years 2020-2050 and compare the results with the historic period 1975-2005. CCT provides four modules to: i) manage big databases such as those of Global Climate Models (GCMs), ii) make bias correction using observed local climate data , iii) interpolate gridded climate data to finer resolution, and iv) calculate continuous dry- and wet-day periods based on rainfall, temperature, and soil moisture for analysis of drought and flooding risks. We used bias-corrected meteorological data of five GCMs for extreme CO2 emission scenario rcp8.5 for California to analyze the trend of extreme hydrological events. The findings indicate that frequency of dry period will increase in center and southern parts of California. The assessment of the number of wet days and the frequency of wet periods suggests an increased risk of flooding in north and north-western part of California, especially in the coastal strip. Keywords: Climate Change Toolkit (CCT), Extreme Hydrological Events, California

  7. Communicating Climate Uncertainties: Challenges and Opportunities Related to Spatial Scales, Extreme Events, and the Warming 'Hiatus'

    NASA Astrophysics Data System (ADS)

    Casola, J. H.; Huber, D.

    2013-12-01

    Many media, academic, government, and advocacy organizations have achieved sophistication in developing effective messages based on scientific information, and can quickly translate salient aspects of emerging climate research and evolving observations. However, there are several ways in which valid messages can be misconstrued by decision makers, leading them to inaccurate conclusions about the risks associated with climate impacts. Three cases will be discussed: 1) Issues of spatial scale in interpreting climate observations: Local climate observations may contradict summary statements about the effects of climate change on larger regional or global spatial scales. Effectively addressing these differences often requires communicators to understand local and regional climate drivers, and the distinction between a 'signal' associated with climate change and local climate 'noise.' Hydrological statistics in Missouri and California are shown to illustrate this case. 2) Issues of complexity related to extreme events: Climate change is typically invoked following a wide range of damaging meteorological events (e.g., heat waves, landfalling hurricanes, tornadoes), regardless of the strength of the relationship between anthropogenic climate change and the frequency or severity of that type of event. Examples are drawn from media coverage of several recent events, contrasting useful and potentially confusing word choices and frames. 3) Issues revolving around climate sensitivity: The so-called 'pause' or 'hiatus' in global warming has reverberated strongly through political and business discussions of climate change. Addressing the recent slowdown in warming yields an important opportunity to raise climate literacy in these communities. Attempts to use recent observations as a wedge between climate 'believers' and 'deniers' is likely to be counterproductive. Examples are drawn from Congressional testimony and media stories. All three cases illustrate ways that decision

  8. Secular environmental precursors to Early Toarcian (Jurassic) extreme climate changes

    NASA Astrophysics Data System (ADS)

    Suan, Guillaume; Mattioli, Emanuela; Pittet, Bernard; Lécuyer, Christophe; Suchéras-Marx, Baptiste; Duarte, Luís Vítor; Philippe, Marc; Reggiani, Letizia; Martineau, François

    2010-02-01

    The Early Toarcian Oceanic Anoxic Event (T-OAE), about 183 myr ago, was a global event of environmental and carbon cycle perturbations, which deeply affected both marine biota and carbonate production. Nevertheless, the long-term environmental conditions prevailing prior to the main phase of marine extinction and carbonate production crisis remain poorly understood. Here we present a ˜ 8 myr-long record of Early Pliensbachian-Middle Toarcian environmental changes from the Lusitanian Basin, Portugal, in order to address the long-term paleoclimatic evolution that ultimately led to carbonate production and biotic crises during the T-OAE. Paleotemperature estimates derived from the oxygen isotope compositions of well-preserved brachiopod shells from two different sections reveal a pronounced ˜ 5 °C cooling in the Late Pliensbachian ( margaritatus- spinatum ammonite Zones boundary). This cooling event is followed by a marked ˜ 7-10 °C seawater warming in the Early Toarcian that, after a second cooling event in the mid- polymorphum Zone, culminates during the T-OAE. Calcium carbonate (CaCO 3) contents, the amount of nannofossil calcite and the mean size of the major pelagic carbonate producer Schizosphaerella, all largely covary with paleotemperatures, indicating a coupling between climatic conditions and both pelagic and neritic CaCO 3 production. Furthermore, the cooling and warming episodes coincided with major marine regressions and transgressions, respectively, suggesting that the growth and decay of ice caps may have exerted a strong control on sea-level fluctuations throughout the studied time interval. This revised chronology of environmental changes shows important similarities with Neogene and Paleozoic episodes of deglacial black shale formation, and thus prompts the reevaluation of ice sheet dynamics as a possible agent of Mesozoic events of extinction and organic-rich sedimentation.

  9. Impacts of Climate Change On The Occurrence of Extreme Events: The Mice Project

    NASA Astrophysics Data System (ADS)

    Palutikof, J. P.; Mice Team

    It is widely accepted that climate change due to global warming will have substan- tial impacts on the natural environment, and on human activities. Furthermore, it is increasingly recognized that changes in the severity and frequency of extreme events, such as windstorm and flood, are likely to be more important than changes in the average climate. The EU-funded project MICE (Modelling the Impacts of Climate Extremes) commenced in January 2002. It seeks to identify the likely changes in the occurrence of extremes of rainfall, temperature and windstorm due to global warm- ing, using information from climate models as a basis, and to study the impacts of these changes in selected European environments. The objectives are: a) to evaluate, by comparison with gridded and station observations, the ability of climate models to successfully reproduce the occurrence of extremes at the required spatial and temporal scales. b) to analyse model output with respect to future changes in the occurrence of extremes. Statistical analyses will determine changes in (i) the return periods of ex- tremes, (ii) the joint probability of extremes (combinations of damaging events such as windstorm followed by heavy rain), (iii) the sequential behaviour of extremes (whether events are well-separated or clustered) and (iv) the spatial patterns of extreme event occurrence across Europe. The range of uncertainty in model predictions will be ex- plored by analysing changes in model experiments with different spatial resolutions and forcing scenarios. c) to determine the impacts of the predicted changes in extremes occurrence on selected activity sectors: agriculture (Mediterranean drought), commer- cial forestry and natural forest ecosystems (windstorm and flood in northern Europe, fire in the Mediterranean), energy use (temperature extremes), tourism (heat stress and Mediterranean beach holidays, changes in the snow pack and winter sports ) and civil protection/insurance (windstorm and flood

  10. Plant adaptation to extreme environments: the example of Cistus salviifolius of an active geothermal alteration field.

    PubMed

    Bartoli, Giacomo; Bottega, Stefania; Forino, Laura M C; Ciccarelli, Daniela; Spanò, Carmelina

    2014-02-01

    Cistus salviifolius is able to colonise one of the most extreme active geothermal alteration fields in terms of both soil acidity and hot temperatures. The analyses of morpho-functional and physiological characters, investigated in leaves of plants growing around fumaroles (G leaves) and in leaves developed by the same plants after transfer into growth chamber under controlled conditions (C leaves) evidenced the main adaptive traits developed by this pioneer plant in a stressful environment. These traits involved leaf shape and thickness, mesophyll compactness, stomatal and trichome densities, chloroplast size. Changes of functional and physiological traits concerned dry matter content, peroxide and lipid peroxidation, leaf area, relative water and pigment contents. A higher reducing power and antioxidant enzymatic activity were typical of G leaves. Though the high levels of stress parameters, G leaves showed stress-induced specific morphogenic and physiological responses putatively involved in their surviving in active geothermal habitats.

  11. Plant adaptation to extreme environments: the example of Cistus salviifolius of an active geothermal alteration field.

    PubMed

    Bartoli, Giacomo; Bottega, Stefania; Forino, Laura M C; Ciccarelli, Daniela; Spanò, Carmelina

    2014-02-01

    Cistus salviifolius is able to colonise one of the most extreme active geothermal alteration fields in terms of both soil acidity and hot temperatures. The analyses of morpho-functional and physiological characters, investigated in leaves of plants growing around fumaroles (G leaves) and in leaves developed by the same plants after transfer into growth chamber under controlled conditions (C leaves) evidenced the main adaptive traits developed by this pioneer plant in a stressful environment. These traits involved leaf shape and thickness, mesophyll compactness, stomatal and trichome densities, chloroplast size. Changes of functional and physiological traits concerned dry matter content, peroxide and lipid peroxidation, leaf area, relative water and pigment contents. A higher reducing power and antioxidant enzymatic activity were typical of G leaves. Though the high levels of stress parameters, G leaves showed stress-induced specific morphogenic and physiological responses putatively involved in their surviving in active geothermal habitats. PMID:24581804

  12. Improving plot- and regional-scale crop models for simulating impacts of climate variability and extremes

    NASA Astrophysics Data System (ADS)

    Tao, F.; Rötter, R.

    2013-12-01

    Many studies on global climate report that climate variability is increasing with more frequent and intense extreme events1. There are quite large uncertainties from both the plot- and regional-scale models in simulating impacts of climate variability and extremes on crop development, growth and productivity2,3. One key to reducing the uncertainties is better exploitation of experimental data to eliminate crop model deficiencies and develop better algorithms that more adequately capture the impacts of extreme events, such as high temperature and drought, on crop performance4,5. In the present study, in a first step, the inter-annual variability in wheat yield and climate from 1971 to 2012 in Finland was investigated. Using statistical approaches the impacts of climate variability and extremes on wheat growth and productivity were quantified. In a second step, a plot-scale model, WOFOST6, and a regional-scale crop model, MCWLA7, were calibrated and validated, and applied to simulate wheat growth and yield variability from 1971-2012. Next, the estimated impacts of high temperature stress, cold damage, and drought stress on crop growth and productivity based on the statistical approaches, and on crop simulation models WOFOST and MCWLA were compared. Then, the impact mechanisms of climate extremes on crop growth and productivity in the WOFOST model and MCWLA model were identified, and subsequently, the various algorithm and impact functions were fitted against the long-term crop trial data. Finally, the impact mechanisms, algorithms and functions in WOFOST model and MCWLA model were improved to better simulate the impacts of climate variability and extremes, particularly high temperature stress, cold damage and drought stress for location-specific and large area climate impact assessments. Our studies provide a good example of how to improve, in parallel, the plot- and regional-scale models for simulating impacts of climate variability and extremes, as needed for

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

    EPA Science Inventory

    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 ...

  14. Simulating the effect of climate extremes on groundwater flow through a lakebed

    USGS Publications Warehouse

    Virdi, Makhan L.; Lee, Terrie M.; Swancar, Amy; Niswonger, Richard G.

    2012-01-01

    Groundwater exchanges with lakes resulting from cyclical wet and dry climate extremes maintain lake levels in the environment in ways that are not well understood, in part because they remain difficult to simulate. To better understand the atypical groundwater interactions with lakes caused by climatic extremes, an original conceptual approach is introduced using MODFLOW-2005 and a kinematic-wave approximation to variably saturated flow that allows lake size and position in the basin to change while accurately representing the daily lake volume and three-dimensional variably saturated groundwater flow responses in the basin. Daily groundwater interactions are simulated for a calibrated lake basin in Florida over a decade that included historic wet and dry departures from the average rainfall. The divergent climate extremes subjected nearly 70% of the maximum lakebed area and 75% of the maximum shoreline perimeter to both groundwater inflow and lake leakage. About half of the lakebed area subject to flow reversals also went dry. A flow-through pattern present for 73% of the decade caused net leakage from the lake 80% of the time. Runoff from the saturated lake margin offset the groundwater deficit only about half of that time. A centripetal flow pattern present for 6% of the decade was important for maintaining the lake stage and generated 30% of all net groundwater inflow. Pumping effects superimposed on dry climate extremes induced the least frequent but most cautionary flow pattern with leakage from over 90% of the actual lakebed area.

  15. Predictions of extreme precipitation and sea-level rise under climate change.

    PubMed

    Senior, C A; Jones, R G; Lowe, J A; Durman, C F; Hudson, D

    2002-07-15

    Two aspects of global climate change are particularly relevant to river and coastal flooding: changes in extreme precipitation and changes in sea level. In this paper we summarize the relevant findings of the IPCC Third Assessment Report and illustrate some of the common results found by the current generation of coupled atmosphere-ocean general circulation models (AOGCMs), using the Hadley Centre models. Projections of changes in extreme precipitation, sea-level rise and storm surges affecting the UK will be shown from the Hadley Centre regional models and the Proudman Oceanographic Laboratory storm-surge model. A common finding from AOGCMs is that in a warmer climate the intensity of precipitation will increase due to a more intense hydrological cycle. This leads to reduced return periods (i.e. more frequent occurrences) of extreme precipitation in many locations. The Hadley Centre regional model simulates reduced return periods of extreme precipitation in a number of flood-sensitive areas of the UK. In addition, simulated changes in storminess and a rise in average sea level around the UK lead to reduced return periods of extreme high coastal water events. The confidence in all these results is limited by poor spatial resolution in global coupled models and by uncertainties in the physical processes in both global and regional models, and is specific to the climate change scenario used. PMID:12804251

  16. Climate change and health in Israel: adaptation policies for extreme weather events.

    PubMed

    Green, Manfred S; Pri-Or, Noemie Groag; Capeluto, Guedi; Epstein, Yoram; Paz, Shlomit

    2013-01-01

    Climatic changes have increased the world-wide frequency of extreme weather events such as heat waves, cold spells, floods, storms and droughts. These extreme events potentially affect the health status of millions of people, increasing disease and death. Since mitigation of climate change is a long and complex process, emphasis has recently been placed on the measures required for adaptation. Although the principles underlying these measures are universal, preparedness plans and policies need to be tailored to local conditions. In this paper, we conducted a review of the literature on the possible health consequences of extreme weather events in Israel, where the conditions are characteristic of the Mediterranean region. Strong evidence indicates that the frequency and duration of several types of extreme weather events are increasing in the Mediterranean Basin, including Israel. We examined the public health policy implications for adaptation to climate change in the region, and proposed public health adaptation policy options. Preparedness for the public health impact of increased extreme weather events is still relatively limited and clear public health policies are urgently needed. These include improved early warning and monitoring systems, preparedness of the health system, educational programs and the living environment. Regional collaboration should be a priority.

  17. Climate change and health in Israel: adaptation policies for extreme weather events

    PubMed Central

    2013-01-01

    Climatic changes have increased the world-wide frequency of extreme weather events such as heat waves, cold spells, floods, storms and droughts. These extreme events potentially affect the health status of millions of people, increasing disease and death. Since mitigation of climate change is a long and complex process, emphasis has recently been placed on the measures required for adaptation. Although the principles underlying these measures are universal, preparedness plans and policies need to be tailored to local conditions. In this paper, we conducted a review of the literature on the possible health consequences of extreme weather events in Israel, where the conditions are characteristic of the Mediterranean region. Strong evidence indicates that the frequency and duration of several types of extreme weather events are increasing in the Mediterranean Basin, including Israel. We examined the public health policy implications for adaptation to climate change in the region, and proposed public health adaptation policy options. Preparedness for the public health impact of increased extreme weather events is still relatively limited and clear public health policies are urgently needed. These include improved early warning and monitoring systems, preparedness of the health system, educational programs and the living environment. Regional collaboration should be a priority. PMID:23805950

  18. Predictions of extreme precipitation and sea-level rise under climate change.

    PubMed

    Senior, C A; Jones, R G; Lowe, J A; Durman, C F; Hudson, D

    2002-07-15

    Two aspects of global climate change are particularly relevant to river and coastal flooding: changes in extreme precipitation and changes in sea level. In this paper we summarize the relevant findings of the IPCC Third Assessment Report and illustrate some of the common results found by the current generation of coupled atmosphere-ocean general circulation models (AOGCMs), using the Hadley Centre models. Projections of changes in extreme precipitation, sea-level rise and storm surges affecting the UK will be shown from the Hadley Centre regional models and the Proudman Oceanographic Laboratory storm-surge model. A common finding from AOGCMs is that in a warmer climate the intensity of precipitation will increase due to a more intense hydrological cycle. This leads to reduced return periods (i.e. more frequent occurrences) of extreme precipitation in many locations. The Hadley Centre regional model simulates reduced return periods of extreme precipitation in a number of flood-sensitive areas of the UK. In addition, simulated changes in storminess and a rise in average sea level around the UK lead to reduced return periods of extreme high coastal water events. The confidence in all these results is limited by poor spatial resolution in global coupled models and by uncertainties in the physical processes in both global and regional models, and is specific to the climate change scenario used.

  19. Projected changes in climate extremes over Qatar and the Arabian Gulf region

    NASA Astrophysics Data System (ADS)

    Kundeti, K.; Kanikicharla, K. K.; Al sulaiti, M.; Khulaifi, M.; Alboinin, N.; Kito, A.

    2015-12-01

    The climate of the State of Qatar and the adjacent region is dominated by subtropical dry, hot desert climate with low annual rainfall, very high temperatures in summer and a big difference between maximum and minimum temperatures, especially in the inland areas. The coastal areas are influenced by the Arabian Gulf, and have lower maximum, but higher minimum temperatures and a higher moisture percentage in the air. The global warming can have profound impact on the mean climate as well as extreme weather events over the Arabian Peninsula that may affect both natural and human systems significantly. Therefore, it is important to assess the future changes in the seasonal/annual mean of temperature and precipitation and also the extremes in temperature and wind events for a country like Qatar. This study assesses the performance of the Coupled Model Inter comparison Project Phase 5 (CMIP5) simulations in present and develops future climate scenarios. The changes in climate extremes are assessed for three future periods 2016-2035, 2046-2065 and 2080-2099 with respect to 1986-2005 (base line) under two RCPs (Representative Concentrate Pathways) - RCP4.5 and RCP8.5. We analyzed the projected changes in temperature and precipitation extremes using several indices including those that capture heat stress. The observations show an increase in warm extremes over many parts in this region that are generally well captured by the models. The results indicate a significant change in frequency and intensity of both temperature and precipitation extremes over many parts of this region which may have serious implications on human health, water resources and the onshore/offshore infrastructure in this region. Data from a high-resolution (20km) AGCM simulation from Meteorological Research Institute of Japan Meteorological Agency for the present (1979-2003) and a future time slice (2075-2099) corresponding to RCP8.5 have also been utilized to assess the impact of climate change on

  20. Population exposure to heat-related extremes: Demographic change vs climate change

    NASA Astrophysics Data System (ADS)

    Jones, B.; O'Neill, B. C.; Tebaldi, C.; Oleson, K. W.

    2014-12-01

    Extreme heat events are projected to increase in frequency and intensity in the coming decades [1]. The physical effects of extreme heat on human populations are well-documented, and anticipating changes in future exposure to extreme heat is a key component of adequate planning/mitigation [2, 3]. Exposure to extreme heat depends not only on changing climate, but also on changes in the size and spatial distribution of the human population. Here we focus on systematically quantifying exposure to extreme heat as a function of both climate and population change. We compare exposure outcomes across multiple global climate and spatial population scenarios, and characterize the relative contributions of each to population exposure to extreme heat. We consider a 2 x 2 matrix of climate and population output, using projections of heat extremes corresponding to RCP 4.5 and RCP 8.5 from the NCAR community land model, and spatial population projections for SSP 3 and SSP 5 from the NCAR spatial population downscaling model. Our primary comparison is across RCPs - exposure outcomes from RCP 4.5 versus RCP 8.5 - paying particular attention to how variation depends on the choice of SSP in terms of aggregate global and regional exposure, as well as the spatial distribution of exposure. We assess how aggregate exposure changes based on the choice of SSP, and which driver is more important, population or climate change (i.e. does that outcome vary more as a result of RCP or SSP). We further decompose the population component to analyze the contributions of total population change, migration, and changes in local spatial structure. Preliminary results from a similar study of the US suggests a four-to-six fold increase in total exposure by the latter half of the 21st century. Changes in population are as important as changes in climate in driving this outcome, and there is regional variation in the relative importance of each. Aggregate population growth, as well as redistribution of

  1. Climate change impacts on rainfall extremes and urban drainage: state-of-the-art review

    NASA Astrophysics Data System (ADS)

    Willems, Patrick; Olsson, Jonas; Arnbjerg-Nielsen, Karsten; Beecham, Simon; Pathirana, Assela; Bülow Gregersen, Ida; Madsen, Henrik; Nguyen, Van-Thanh-Van

    2013-04-01

    Under the umbrella of the IWA/IAHR Joint Committee on Urban Drainage, the International Working Group on Urban Rainfall (IGUR) has reviewed existing methodologies for the analysis of long-term historical and future trends in urban rainfall extremes and their effects on urban drainage systems, due to anthropogenic climate change. Current practises have several limitations and pitfalls, which are important to be considered by trend or climate change impact modellers and users of trend/impact results. The review considers the following aspects: Analysis of long-term historical trends due to anthropogenic climate change: influence of data limitation, instrumental or environmental changes, interannual variations and longer term climate oscillations on trend testing results. Analysis of long-term future trends due to anthropogenic climate change: by complementing empirical historical data with the results from physically-based climate models, dynamic downscaling to the urban scale by means of Limited Area Models (LAMs) including explicitly small-scale cloud processes; validation of RCM/GCM results for local conditions accounting for natural variability, limited length of the available time series, difference in spatial scales, and influence of climate oscillations; statistical downscaling methods combined with bias correction; uncertainties associated with the climate forcing scenarios, the climate models, the initial states and the statistical downscaling step; uncertainties in the impact models (e.g. runoff peak flows, flood or surcharge frequencies, and CSO frequencies and volumes), including the impacts of more extreme conditions than considered during impact model calibration and validation. Implications for urban drainage infrastructure design and management: upgrading of the urban drainage system as part of a program of routine and scheduled replacement and renewal of aging infrastructure; how to account for the uncertainties; flexible and sustainable solutions

  2. Expected climate change impacts on extreme flows in Vietnam: The limits of bias correction techniques

    NASA Astrophysics Data System (ADS)

    Laux, Patrick; Dang, Thinh; Kunstmann, Harald

    2016-04-01

    We investigate possible impacts of climate change on future floods in the VuGia-ThuBon river basin, central Vietnam using a multi-model climate ensemble. An ensemble of regional climate projections (SRES) derived from different combinations of global and regional climate models in combination with different emission scenarios are used. In order to correct for the biases between the modelled climate variables and the observations, different bias correction techniques such as linear scaling, local intensity scaling, and quantile mapping are applied to the RCM outputs. Bias-corrected and raw climate data are then used as input for the fully distributed hydrological water balance model WaSIM-ETH to reproduce discharge data at NongSon station. Annual maximum discharges are extracted from the modeled daily series from the control period (1980-1999) and the future periods 2011-2030, 2031-2050, and 2080-2099 for subsequent extreme frequency analyses. To derive flood frequency curves for the four time periods, the generalized extreme value probability distribution is fitted to the data. Our analysis shows that actually none of the bias correction approaches applied to the control runs of simulated precipitation data can satisfactorily correct their distributions towards those of the observations. Therefore, this study builds further on the delta change approach, which adjusts the observed extreme values by the derived signals from the hydrological simulations fed by raw future climate projections. Adjusted return periods of e.g. HQ100 values are calculated based on the delta change method. The results inhibit a remarkable variation among the different climate scenarios in representing extreme values. Results show that MRI-MRI, ECHAM3-REMO, HadCMQ10-HadRM3P and HadCMQ13-HadRM3P models always exhibit a positive signal for all considered time slices and climate change scenarios. On the other hand, CCSM-MM5 frequently shows a negative signal for all time slices. On average, an

  3. Can dynamically downscaled climate model outputs improve projections of extreme precipitation events?

    NASA Astrophysics Data System (ADS)

    Wobus, C. W.; Reynolds, L.; Jones, R.; Horton, R. M.; Smith, J. B.; Fries, J. S.; Tryby, M.; Spero, T.; Nolte, C. G.

    2015-12-01

    Many of the storms that generate damaging floods are caused by locally intense, sub-daily precipitation, yet the spatial and temporal resolution of the most widely available climate model outputs are both too coarse to simulate these events. Thus there is often a disconnect between the nature of the events that cause damaging floods and the models used to project how climate change might influence their magnitude. This could be a particular problem when developing scenarios to inform future stormwater management options under future climate scenarios. In this study we sought to close this gap, using sub-daily outputs from the Weather Research and Forecasting model (WRF) from each of the nine climate regions in the United States. Specifically, we asked 1) whether WRF outputs projected consistent patterns of change for sub-daily and daily precipitation extremes; and 2) whether this dynamically downscaled model projected different magnitudes of change for 3-hourly vs 24-hourly extreme events. We extracted annual maximum values for 3-hour through 24-hour precipitation totals from an 11-year timeseries of hindcast (1995-2005) and mid-century (2045-2055) climate, and calculated the direction and magnitude of change for 3-hour and 24-hour extreme events over this timeframe. The model results project that the magnitude of both 3-hour and 24-hour events will increase over most regions of the United States, but there was no clear or consistent difference in the relative magnitudes of change for sub-daily vs daily events.

  4. [Extreme Climatic Events in the Altai Republic According to Dendrochronological Data].

    PubMed

    Barinov, V V; Myglan, V S; Nazarov, A N; Vaganov, E A; Agatova, A R; Nepop, R K

    2016-01-01

    The results of dating of extreme climatic events by damage to the anatomical structure and missing tree rings of the Siberian larch in the upper forest boundary of the Altai Republic are given. An analysis of the spatial distribution of the revealed dates over seven plots (Kokcy, Chind, Ak-ha, Jelo, Tute, Tara, and Sukor) allowed us to distinguish the extreme events on interregional (1700, 1783, 1788, 1812, 1814, 1884), regional (1724, 1775, 1784, 1835, 1840, 1847, 1850, 1852, 1854, 1869, 1871, 1910, 1917, 1927, 1938, 1958, 1961), and local (1702, 1736, 1751, 1785, 1842, 1843,1874, 1885, 1886, 1919, 2007, and 2009) scales. It was shown that the events of an interregional scale correspond with the dates of major volcanic eruptions (Grimsvotn, Lakagigar, Etna, Awu, Tambora, Soufriere St. Vinsent, Mayon, and Krakatau volcanos) and extreme climatic events, crop failures, lean years, etc., registered in historical sources. PMID:27396180

  5. [Extreme Climatic Events in the Altai Republic According to Dendrochronological Data].

    PubMed

    Barinov, V V; Myglan, V S; Nazarov, A N; Vaganov, E A; Agatova, A R; Nepop, R K

    2016-01-01

    The results of dating of extreme climatic events by damage to the anatomical structure and missing tree rings of the Siberian larch in the upper forest boundary of the Altai Republic are given. An analysis of the spatial distribution of the revealed dates over seven plots (Kokcy, Chind, Ak-ha, Jelo, Tute, Tara, and Sukor) allowed us to distinguish the extreme events on interregional (1700, 1783, 1788, 1812, 1814, 1884), regional (1724, 1775, 1784, 1835, 1840, 1847, 1850, 1852, 1854, 1869, 1871, 1910, 1917, 1927, 1938, 1958, 1961), and local (1702, 1736, 1751, 1785, 1842, 1843,1874, 1885, 1886, 1919, 2007, and 2009) scales. It was shown that the events of an interregional scale correspond with the dates of major volcanic eruptions (Grimsvotn, Lakagigar, Etna, Awu, Tambora, Soufriere St. Vinsent, Mayon, and Krakatau volcanos) and extreme climatic events, crop failures, lean years, etc., registered in historical sources.

  6. Projected changes of extreme precipitation over Contiguous United States with Nested regional climate model (NRCM)

    NASA Astrophysics Data System (ADS)

    Wang, J.

    2013-12-01

    Extreme weather events have already significantly influenced North America. During 2005-2011, the extreme events have increased by 250 %, from four or fewer events occurring in 2005, while 14 events occurring in 2011 (www.ncdc.noaa.gov/billions/). In addition, extreme rainfall amounts, frequency, and intensity were all expected to increase under greenhouse warming scenarios (Wehner 2005; Kharin et al. 2007; Tebaldi et al. 2006). Global models are powerful tools to investigate the climate and climate change on large scales. However, such models do not represent local terrain and mesoscale weather systems well owing to their coarse horizontal resolution (150-300 km). To capture the fine-scale features of extreme weather events, regional climate models (RCMs) with a more realistic representation of the complex terrain and heterogeneous land surfaces are needed (Mass et al. 2002). This study uses the Nested Regional Climate model (NRCM) to perform regional scale climate simulations on a 12-km × 12-km high resolution scale over North America (including Alaska; with 600 × 515 grid cells at longitude and latitude), known as CORDEX_North America, instead of small regions as studied previously (eg., Dominguez et al. 2012; Gao et al. 2012). The performance and the biases of the NRCM extreme precipitation calculations (2000-2010) have been evaluated with PRISM precipitation (Daly et al. 1997) by Wang and Kotamarthi (2013): the NRCM replicated very well the monthly amount of extreme precipitation with less than 3% overestimation over East CONUS, and the frequency of extremes over West CONUS and upper Mississippi River Basin. The Representative Concentration Pathway (RCP) 8.5 and RCP 4.5 from the new Community Earth System Model version 1.0 (CESM v1.0) are dynamically downscaled to predict the extreme rainfall events at the end-of-century (2085-2095) and to explore the uncertainties of future extreme precipitation induced by different scenarios over distinct regions. We have

  7. Spatiotemporal variability of extreme precipitation in Shaanxi province under climate change

    NASA Astrophysics Data System (ADS)

    Jiang, Rengui; Xie, Jiancang; Zhao, Yong; He, Hailong; He, Guohua

    2016-09-01

    Extreme climate index is one of the useful tools to monitor and detect climate change. The primary objective of this study is to provide a more comprehensively the changes in extreme precipitation between the periods of 1954-1983 and 1984-2013 in Shaanxi province under climate change, which will hopefully provide a scientific understanding of the precipitation-related natural hazards such as flood and drought. Daily precipitation from 34 surface meteorological stations were used to calculated 13 extreme precipitation indices (EPIs) generated by the joint World Meteorological Organization Commission for Climatology (CCI)/World Climate Research Programme (WCRP) project on Climate Variability and Predictability (CLIVAR) expect Team on climate change Detection, Monitoring and Indices (ETCCDMI). Two periods including 1954-1983 and 1984-2013 were selected and five types of precipitation days (R10mm-R100mm) were defined, to provide more evidences of climate change impacts on the extreme precipitation events, and specially, to investigate the changes in different types of precipitation days. The EPIs were generated using RClimRex software, and the trends were analyzed using Mann-Kendall nonparametric test and Sen's slope estimator. The relationships between the EPIs and the impacts of climate anomalies on typical EPIs were investigated using correlation and composite analysis. The mainly results include: 1) Thirteen EPIs, except consecutive dry day (CDD), were positive trends dominated for the period of 1984-2013, but the trends were not obvious for the period of 1954-1983. Most of the trends were not statistically significant at 5 % significance level. 2) The spatial distributions of stations that exhibited positive and negative trends were scattered. However, the stations that had negative trends mainly distributed in the north of Shaanxi province, and the stations that had positive trends mainly located in the south. 3) The percentage of stations that had positive

  8. Bias-corrected regional climate projections of extreme rainfall in south-east Australia

    NASA Astrophysics Data System (ADS)

    Evans, Jason P.; Argueso, D.; Olson, R.; Di Luca, A.

    2016-09-01

    This study presents future changes in extreme precipitation as projected within the New South Wales and Australian Capital Territory Regional Climate Modelling (NARCliM) project's regional climate ensemble for south-east Australia. Model performance, independence and projected future changes were considered when designing the ensemble. We applied a quantile mapping bias correction to the climate model outputs based on theoretical distribution functions, and the implications of this for the projected precipitation extremes is investigated. Precipitation extremes are quantified using several indices from the Expert Team on Climate Change Detection and Indices set of indices. The bias correction was successful in removing most of the magnitude bias in extreme precipitation but does not correct biases in the length of maximum wet and dry spells. The bias correction also had a relatively small effect on the projected future changes. Across a range of metrics, robust increases in the magnitude of precipitation extreme indices are found. While these increases are often in-line with a continuation of the trends present over the last century, they are not found to be statistically significant within the ensemble as a whole. The length of the maximum consecutive wet spell is projected to remain at present-day levels, while the length of the maximum dry spell is projected to increase into the future. The combination of longer dry spells and increases in extreme precipitation magnitude indicate an important change in the character of the precipitation time series. This could have considerable hydrological implications since changes in the sequencing of events can be just as important as changes in event magnitude for hydrological impacts.

  9. Toward enhanced understanding and projections of climate extremes using physics-guided data mining techniques

    NASA Astrophysics Data System (ADS)

    Ganguly, A. R.; Kodra, E. A.; Banerjee, A.; Boriah, S.; Chatterjee, S.; Chatterjee, S.; Choudhary, A.; Das, D.; Faghmous, J.; Ganguli, P.; Ghosh, S.; Hayhoe, K.; Hays, C.; Hendrix, W.; Fu, Q.; Kawale, J.; Kumar, D.; Kumar, V.; Liess, S.; Mawalagedara, R.; Mithal, V.; Oglesby, R.; Salvi, K.; Snyder, P. K.; Steinhaeuser, K.; Wang, D.; Wuebbles, D.

    2014-02-01

    Extreme events such as heat waves, cold spells, floods, droughts, tropical cyclones, and tornadoes have potentially devastating impacts on natural and engineered systems, and human communities, worldwide. Stakeholder decisions about critical infrastructures, natural resources, emergency preparedness and humanitarian aid typically need to be made at local to regional scales over seasonal to decadal planning horizons. However, credible climate change attribution and reliable projections at more localized and shorter time scales remain grand challenges. Long-standing gaps include inadequate understanding of processes such as cloud physics and ocean-land-atmosphere interactions, limitations of physics-based computer models, and the importance of intrinsic climate system variability at decadal horizons. Meanwhile, the growing size and complexity of climate data from model simulations and remote sensors increases opportunities to address these scientific gaps. This perspectives article explores the possibility that physically cognizant mining of massive climate data may lead to significant advances in generating credible predictive insights about climate extremes and in turn translating them to actionable metrics and information for adaptation and policy. Specifically, we propose that data mining techniques geared towards extremes can help tackle the grand challenges in the development of interpretable climate projections, predictability, and uncertainty assessments. To be successful, scalable methods will need to handle what has been called "Big Data" to tease out elusive but robust statistics of extremes and change from what is ultimately small data. Physically-based relationships (where available) and conceptual understanding (where appropriate) are needed to guide methods development and interpretation of results. Such approaches may be especially relevant in situations where computer models may not be able to fully encapsulate current process understanding, yet the

  10. Toward enhanced understanding and projections of climate extremes using physics-guided data mining techniques

    NASA Astrophysics Data System (ADS)

    Ganguly, A. R.; Kodra, E. A.; Agrawal, A.; Banerjee, A.; Boriah, S.; Chatterjee, Sn.; Chatterjee, So.; Choudhary, A.; Das, D.; Faghmous, J.; Ganguli, P.; Ghosh, S.; Hayhoe, K.; Hays, C.; Hendrix, W.; Fu, Q.; Kawale, J.; Kumar, D.; Kumar, V.; Liao, W.; Liess, S.; Mawalagedara, R.; Mithal, V.; Oglesby, R.; Salvi, K.; Snyder, P. K.; Steinhaeuser, K.; Wang, D.; Wuebbles, D.

    2014-07-01

    Extreme events such as heat waves, cold spells, floods, droughts, tropical cyclones, and tornadoes have potentially devastating impacts on natural and engineered systems and human communities worldwide. Stakeholder decisions about critical infrastructures, natural resources, emergency preparedness and humanitarian aid typically need to be made at local to regional scales over seasonal to decadal planning horizons. However, credible climate change attribution and reliable projections at more localized and shorter time scales remain grand challenges. Long-standing gaps include inadequate understanding of processes such as cloud physics and ocean-land-atmosphere interactions, limitations of physics-based computer models, and the importance of intrinsic climate system variability at decadal horizons. Meanwhile, the growing size and complexity of climate data from model simulations and remote sensors increases opportunities to address these scientific gaps. This perspectives article explores the possibility that physically cognizant mining of massive climate data may lead to significant advances in generating credible predictive insights about climate extremes and in turn translating them to actionable metrics and information for adaptation and policy. Specifically, we propose that data mining techniques geared towards extremes can help tackle the grand challenges in the development of interpretable climate projections, predictability, and uncertainty assessments. To be successful, scalable methods will need to handle what has been called "big data" to tease out elusive but robust statistics of extremes and change from what is ultimately small data. Physically based relationships (where available) and conceptual understanding (where appropriate) are needed to guide methods development and interpretation of results. Such approaches may be especially relevant in situations where computer models may not be able to fully encapsulate current process understanding, yet the

  11. Assessing extreme values for water management purposes in the context of climate change

    NASA Astrophysics Data System (ADS)

    Kallache, M.

    2012-04-01

    Extreme events are often defined as rare events, for example floods or heavy precipitation events. Then very extreme events cannot be counted any more, and the use of a theoretical distribution to extrapolate to yet not observed quantiles is a general approach. Extreme value theory (EVT) deals with the specific characteristics of extreme values, for example their asymmetric distribution, and provides according theoretical distributions. In hydrology, the use of EVT has a long tradition. A prominent example is the estimation of 100-year flood return levels for water management purposes. It is likely that changes to hydrological extremes due to climate change will have a great impact on human society in the future: Temperature increase might amplify the occurrence of heavy precipitation events due to an increased water-holding capacity of the atmosphere. On the other hand, regions, which are already vulnerable to water stress, might have to cope with an intensification of droughts. The adequate description of the characteristics of extreme hydrological events and their changes is thus a core element of risk assessment and water management. In this talk, examples of the use of EVT to assess hydrological extremes are given. Results for flood occurrence in Southern Germany and droughts in Central Spain will be presented. A focus will be set on the treatment of temporal or spatial evolving extremes, and the assessment of future changes.

  12. Climate Resiliency Planning: Making Extreme Event Science Useful for Managers and Planners in Northern Nevada

    NASA Astrophysics Data System (ADS)

    McCarthy, M.; Kenneston, A.; Wall, T. U.; Brown, T. J.; Redmond, K. T.

    2014-12-01

    Effective climate resiliency planning at the regional level requires extensive interactive dialogue among climate scientists, emergency managers, public health officials, urban planners, social scientists, and policy makers. Engaging federal, tribal, state, local governments and private sector business and infrastructure owners/operators in defining, assessing and characterizing the impacts of extreme events allows communities to understand how different events "break the system" forcing local communities to seek support and resources from state/federal governments and/or the private sector and what actions can be taken proactively to mitigate consequences and accelerate recovery. The Washoe County Regional Resiliency Study was prepared in response to potential climate variability related impacts specific to the Northern Nevada Region. The last several decades have seen dramatic growth in the region, coupled with increased resource demands that have forced local governments to consider how those impacts will affect the region and may, in turn, impact the region's ability to provide essential services. The Western Regional Climate Center of the Desert Research Institute provided a synthesis of climate studies with predictions regarding plausible changes in the local climate of Northern California and Nevada for the next 50 years. In general, these predictions indicate that the region's climate is undergoing a gradual shift, which will primarily affect the frequency, amount, and form of precipitation in the Sierra Nevada and Great Basin. Changes in water availability and other extreme events may have serious and long lasting effects in the Northern Nevada Region, and create a variety of social, environmental and economic concerns. A range of extreme events were considered including Adverse Air Quality, Droughts, Floods, Heat Waves, High Wind, Structure Fires, Wildland Fires, and Major Winter Storms. Due to the complexity of our climate systems, and the difficulty in

  13. The historical impact of climate extremes on global agricultural production and trade

    NASA Astrophysics Data System (ADS)

    Troy, T. J.; Pal, I.; Block, P. J.; Lall, U.

    2011-12-01

    How does climate variability at interannual time scales impact the volume and prices of key agricultural products on the global market? Do concurrent climate shocks in major breadbaskets of the world have serious impacts on global stocks and food prices? To what extent may irrigated agriculture or food storage buffer such impacts? Is there evidence of such impacts and/or buffering in the publicly available historical data? This talk explores these questions through empirical data analysis. During the past two years, we have seen drought in China, Europe, and Russia and floods in the United States and Australia. In this study, we examine the relationship between climate and crop yields, focusing on three main grain staples: wheat, rice, and maize. To do this, we use global production, trade, and stock data from the Food and Agricultural Organization and the United States Department of Agriculture for agriculture information and gridded observations of temperature and precipitation from 1960 through 2008. We focus on the impact of climate shocks (extreme temperatures, drought, and floods) on the agricultural production for the top exporting countries and quantify how these shocks propagate through the country's exports, imports, and grain stocks in order to understand the effect climate variability and extremes have on global food security. The ability to forecast these climate shocks at seasonal to longer lead times would significantly improve our ability to cope with perturbations in the global food supply, and we evaluate the ability of current models to produce skillful seasonal forecasts over the major grain producing regions.

  14. Key ecological responses to nitrogen are altered by climate change

    EPA Science Inventory

    Here we review the effects of nitrogen and climate (e.g. temperature and precipitation) on four aspects of ecosystem structure and function including hydrologic-coupled nitrogen cycling, carbon cycling, acidification and biodiversity.

  15. Extreme climate, rather than population history, explains mid-facial morphology of Northern Asians.

    PubMed

    Evteev, Andrej; Cardini, Andrea L; Morozova, Irina; O'Higgins, Paul

    2014-03-01

    Previous studies have examined mid-facial cold adaptation among either widely dispersed and genetically very diverse groups of humans isolated for tens of thousands of years, or among very closely related groups spread over climatically different regions. Here we present a study of one East Asian and seven North Asian populations in which we examine the evidence for convergent adaptations of the mid-face to a very cold climate. Our findings indicate that mid-facial morphology is strongly associated with climatic variables that contrast the temperate climate of East Asians and the very cold and dry climate of North Asians. This is also the case when either maxillary or nasal cavity measurements are considered alone. The association remains significant when mtDNA distances among populations are taken into account. The morphological contrasts between populations are consistent with physiological predictions and prior studies of mid-facial cold adaptation in more temperate regions, but among North Asians there appear to be some previously undescribed morphological features that might be considered as adaptive to extreme cold. To investigate this further, analyses of the seven North Asian populations alone suggest that mid-facial morphology remains strongly associated with climate, particularly winter precipitation, contrasting coastal Arctic and continental climates. However, the residual covariation among North Asian mid-facial morphology and climate when genetic distances are considered, is not significant. These findings point to modern adaptations to extreme climate that might be relevant to our understanding of the mid-facial morphology of fossil hominins that lived during glaciations.

  16. Analysis of Extreme Events in Regional Climate Model Simulations for the Pacific Northwest using weatherathome

    NASA Astrophysics Data System (ADS)

    Mera, R. J.; Mote, P.; Weber, J.

    2011-12-01

    One of the most prominent impacts of climate change over the Pacific Northwest is the potential for an elevated number of extreme precipitation events over the region. Planning for natural hazards such as increasing number of floods related to high-precipitation events have, in general, focused on avoiding development in floodplains and conditioning development to withstand inundation with a minimum of losses. Nationwide, the Federal Emergency Management Agency (FEMA) estimates that about one quarter of its payments cover damage that has occurred outside mapped floodplains. It is clear that traditional flood-based planning will not be sufficient to predict and avoid future losses resulting from climate-related hazards such as high-precipitation events. In order to address this problem, the present study employs regional climate model output for future climate change scenarios to aid with the development of a map-based inventory of future hazard risks that can contribute to the development of a "planning-scale" decision support system for the Oregon Department of Land Conservation and Development (DLCD). Climate model output is derived from the climateprediction.net (CPDN) weatherathome project, an innovative climate science experiment that utilizes volunteer computers from users worldwide to produce hundreds of thousands superensembles of regional climate simulations of the Western United States climate from 1950 to 2050. The spatial and temporal distribution of extreme weather events are analyzed for the Pacific Northwest to diagnose the model's capabilities as an input for map products such as impacts on hydrology. Special attention is given to intensity and frequency of Atmospheric River events in historical and future climate contexts.

  17. Air quality extremes and trends over the United States: Effects of regional climate

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Song, Y.; Loadholt, J.; Zhang, H.; Park, T.; Deng, Y.; Zhang, Y.

    2014-12-01

    We apply a suite of analysis methods, including statistical distribution and correlation, empirical orthogonal function (EOF), linear inverse modeling (LIM), and historical modeling using regional air quality and global chemistry-climate models, to analyze surface ozone (since 1980) and PM2.5 (since 2000) measurements from EPA observation networks. The overarching goal is to understand how regional climate and weather systems affect air quality trends and extreme events. Previous studies documented high or geographically specific ozone episodes and identified contributions from anticyclone, transport, or sub-decadal to decadal time scale patterns pertinent to the events. Here, an ensemble analysis of all events from single day to multi-day episodes in the past three decades places all episodes into a continuum of time and geospatial coordinates. Inter-annual patterns linked to source concentrations and seasonal transport are evident, but anomalies such as unseasonable and persistent anticyclones to winter events over snow cover can also be identified. Overlapping events between ozone and temperature extremes are identified. They tend to occur in eastern and western coast regions with significant local variability. The occurrence frequency of overlapping events decreased from 1980s to 2000s. PM2.5 extreme showed more sensitivity to extreme temperature than drought index. When being divided by two periods (2000-2004 and 2005-2009), the second period had more extreme PM events at lower temperature in winter time. An EOF analysis was conducted to examine how regional and hemispheric climate variability affects the ozone extreme events. A question explored here is how well EOF analysis that links ozone concentrations to climate variables explains the temporal and geospatial variability of extreme ozone events (days and episodes >= 75 ppbv). The seasonal change in controlling weather systems plays a key role in how regional climate affects air quality. We also show the

  18. Understanding the link between aridity and hydrological extremes: Lessons from hyper-arid climates

    NASA Astrophysics Data System (ADS)

    Molini, Annalisa

    2016-04-01

    Precipitation over arid and hyper-arid regions represents "per se" an extreme event, often resulting in surface-hydrologic impacts comparatively more catastrophic than in temperate climates. The spatio-temporal distribution of precipitation through arid climates is in fact characterized by intense and short-lived patterns and intimately related to the local availability of water and energy. However - given the scarcity of data and the limited number of research contributions analyzing rain extremes in hyper arid environments - is still an open question whether rainfall sporadically falling on hyper-arid regions, and in particular its convective component, presents peculiar features connected with the endemically water-limited regime of these regions. If so, understanding the link between aridity and rainfall variability could turn out a precious tool to investigate not only the climate of arid regions but also more global trends of precipitation under global warming and aridification. In this contribution we analyze the connection between rainfall variability, its temporal scaling laws and aridity in a climatological prospective. Through a wide dataset of precipitation time series covering most Continental US (CONUS) we explore the local dependence of classic intermittency measures on aridity, finding evidence of a well-defined variability patterns across a wide range of water-limited climates. We also explore the connection between different intermittency features of arid climates as contrasted with "wet" regions and briefly discuss the links between clustering, water-availability thresholds and hydro-climatic extremes. Our findings provide a framework to better understand the link between intermittency, rainfall scaling and climate in water-limited regions of the world, with possible extension to global aridification studies.

  19. Managing the risks of extreme events and disasters to advance climate change adaptation. Special report of the Intergovernmental Panel on Climate Change (IPCC)

    SciTech Connect

    Field, C.B.; Barros, V.; Stocker, T.F.

    2012-07-01

    This Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX) has been jointly coordinated by Working Groups I (WGI) and II (WGII) of the Intergovernmental Panel on Climate Change (IPCC). The report focuses on the relationship between climate change and extreme weather and climate events, the impacts of such events, and the strategies to manage the associated risks. This Special Report, in particular, contributes to frame the challenge of dealing with extreme weather and climate events as an issue in decision making under uncertainty, analyzing response in the context of risk management. The report consists of nine chapters, covering risk management; observed and projected changes in extreme weather and climate events; exposure and vulnerability to as well as losses resulting from such events; adaptation options from the local to the international scale; the role of sustainable development in modulating risks; and insights from specific case studies. (LN)

  20. Data informatics for the Detection, Characterization, and Attribution of Climate Extremes

    NASA Astrophysics Data System (ADS)

    Collins, W.; Wehner, M. F.; O'Brien, T. A.; Paciorek, C. J.; Krishnan, H.; Johnson, J. N.; Prabhat, M.

    2015-12-01

    The potential for increasing frequency and intensity of extremephenomena including downpours, heat waves, and tropical cyclonesconstitutes one of the primary risks of climate change for society andthe environment. The challenge of characterizing these risks is thatextremes represent the "tails" of distributions of atmosphericphenomena and are, by definition, highly localized and typicallyrelatively transient. Therefore very large volumes of observationaldata and projections of future climate are required to quantify theirproperties in a robust manner. Massive data analytics are required inorder to detect individual extremes, accumulate statistics on theirproperties, quantify how these statistics are changing with time, andattribute the effects of anthropogenic global warming on thesestatistics. We describe examples of the suite of techniques the climate communityis developing to address these analytical challenges. The techniquesinclude massively parallel methods for detecting and trackingatmospheric rivers and cyclones; data-intensive extensions togeneralized extreme value theory to summarize the properties ofextremes; and multi-model ensembles of hindcasts to quantify theattributable risk of anthropogenic influence on individual extremes.We conclude by highlighting examples of these methods developed by ourCASCADE (Calibrated and Systematic Characterization, Attribution, andDetection of Extremes) project.

  1. Will climate change increase the risk for critical infrastructure failures in Europe due to extreme precipitation?

    NASA Astrophysics Data System (ADS)

    Nissen, Katrin; Ulbrich, Uwe

    2016-04-01

    An event based detection algorithm for extreme precipitation is applied to a multi-model ensemble of regional climate model simulations. The algorithm determines extent, location, duration and severity of extreme precipitation events. We assume that precipitation in excess of the local present-day 10-year return value will potentially exceed the capacity of the drainage systems that protect critical infrastructure elements. This assumption is based on legislation for the design of drainage systems which is in place in many European countries. Thus, events exceeding the local 10-year return value are detected. In this study we distinguish between sub-daily events (3 hourly) with high precipitation intensities and long-duration events (1-3 days) with high precipitation amounts. The climate change simulations investigated here were conducted within the EURO-CORDEX framework and exhibit a horizontal resolution of approximately 12.5 km. The period between 1971-2100 forced with observed and scenario (RCP 8.5 and RCP 4.5) greenhouse gas concentrations was analysed. Examined are changes in event frequency, event duration and size. The simulations show an increase in the number of extreme precipitation events for the future climate period over most of the area, which is strongest in Northern Europe. Strength and statistical significance of the signal increase with increasing greenhouse gas concentrations. This work has been conducted within the EU project RAIN (Risk Analysis of Infrastructure Networks in response to extreme weather).

  2. Developing research about extreme events and impacts to support international climate policy

    NASA Astrophysics Data System (ADS)

    Otto, Friederike; James, Rachel; Parker, Hannah; Boyd, Emily; Jones, Richard; Allen, Myles; Mitchell, Daniel; Cornforth, Rosalind

    2015-04-01

    Climate change is expected to have some of its most significant impacts through changes in the frequency and severity of extreme events. There is a pressing need for policy to support adaptation to changing climate risks, and to deal with residual loss and damage from climate change. In 2013, the Warsaw International Mechanism was established by the United Nations Framework Convention on Climate Change (UNFCCC) to address loss and damage in developing countries. Strategies to help vulnerable regions cope with losses from extreme events will presumably require information about the influence of anthropogenic forcing on extreme weather. But what kind of scientific evidence will be most useful for the Warsaw Mechanism? And how can the scientific communities working on extreme events and impacts develop their research to support the advance of this important policy? As climate scientists conducting probabilistic event attribution studies, we have been working with social scientists to investigate these questions. Our own research seeks to examine the role of external drivers, including greenhouse gas emissions, on the risk of extreme weather events such as heatwaves, flooding, and drought. We use large ensembles of climate models to compute the probability of occurrence of extreme events under current conditions and in a world which might have been without anthropogenic interference. In cases where the models are able to simulate extreme weather, the analysis allows for conclusions about the extent to which climate change may have increased, decreased, or made no change to the risk of the event occurring. These results could thus have relevance for the UNFCCC negotiations on loss and damage, and we have been communicating with policymakers and observers to the policy process to better understand how we can develop our research to support their work; by attending policy meetings, conducting interviews, and using a participatory game developed with the Red Cross

  3. Climate Central World Weather Attribution (WWA) project: Real-time extreme weather event attribution analysis

    NASA Astrophysics Data System (ADS)

    Haustein, Karsten; Otto, Friederike; Uhe, Peter; Allen, Myles; Cullen, Heidi

    2015-04-01

    Extreme weather detection and attribution analysis has emerged as a core theme in climate science over the last decade or so. By using a combination of observational data and climate models it is possible to identify the role of climate change in certain types of extreme weather events such as sea level rise and its contribution to storm surges, extreme heat events and droughts or heavy rainfall and flood events. These analyses are usually carried out after an extreme event has occurred when reanalysis and observational data become available. The Climate Central WWA project will exploit the increasing forecast skill of seasonal forecast prediction systems such as the UK MetOffice GloSea5 (Global seasonal forecasting system) ensemble forecasting method. This way, the current weather can be fed into climate models to simulate large ensembles of possible weather scenarios before an event has fully emerged yet. This effort runs along parallel and intersecting tracks of science and communications that involve research, message development and testing, staged socialization of attribution science with key audiences, and dissemination. The method we employ uses a very large ensemble of simulations of regional climate models to run two different analyses: one to represent the current climate as it was observed, and one to represent the same events in the world that might have been without human-induced climate change. For the weather "as observed" experiment, the atmospheric model uses observed sea surface temperature (SST) data from GloSea5 (currently) and present-day atmospheric gas concentrations to simulate weather events that are possible given the observed climate conditions. The weather in the "world that might have been" experiments is obtained by removing the anthropogenic forcing from the observed SSTs, thereby simulating a counterfactual world without human activity. The anthropogenic forcing is obtained by comparing the CMIP5 historical and natural simulations

  4. Analysis of climate change effects on extreme precipitation for the area of Sicily (Italy)

    NASA Astrophysics Data System (ADS)

    Forestieri, Angelo; Fowler, Hayley; Lo Conti, Francesco; Noto, Leonardo

    2016-04-01

    In this study possible effects of the climate change on the extreme precipitation events have been analyzed by means of the CORDEX (Coordinated Regional climate Downscaling Experiment) data, a WCRP-sponsored program for the study of climate change effects at regional scales. In particular, some models runs from the EURO-CORDEX and the MED-CORDEX, i.e., two branch of the main project, have been exploited for the analysis of possible effects on extreme rainfall for the area of Sicily (Italy). In order to improve the reliability of reference data retrieved from the CORDEX datasets, a bias correction procedure based on hystorical measurements has been designed. Moreover, a simple cascade temporal downscaling procedure, has been applied for the derivation of sub-daily data. Results highlight that mean annual precipitation for the period 2006-2050 shows a reduction of the average total precipitation for both scenarios, rcp8.5 more than rcp4.5. The precipitation for the shorter durations has shown an increase respect to higher durations. This behaviour is confirmed by many works of the scientific community, which underline this trend. Therefore, results report the indications that in this area the up to date climate predictions are congruent with future scenarios characterized by a decrease of the total amount of precipitation with an increase of the extreme rainfall events.

  5. Climate Change and Fetal Health: The Impacts of Exposure to Extreme Temperatures in New York City

    NASA Technical Reports Server (NTRS)

    Ngo, Nicole S.; Horton, Radley M.

    2015-01-01

    Background: Climate change is projected to increase the frequency, intensity, and duration of heat waves while reducing cold extremes, yet few studies have examined the relationship between temperature and fetal health. Objectives: We estimate the impacts of extreme temperatures on birth weight and gestational age in Manhattan, a borough in New York City, and explore differences by socioeconomic status (SES). Methods: We combine average daily temperature from 1985 to 2010 with birth certificate data in Manhattan for the same time period. We then generate 33 downscaled climate model time series to project impacts on fetal health. Results: We find exposure to an extra day where average temperature 25 F and 85 F during pregnancy is associated with a 1.8 and 1.7 g (respectively) reduction in birth weight, but the impact varies by SES, particularly for extreme heat, where teen mothers seem most vulnerable. We find no meaningful, significant effect on gestational age. Using projections of temperature from these climate models, we project average net reductions in birth weight in the 2070- 2099 period of 4.6 g in the business-as-usual scenario. Conclusions: Results suggest that increasing heat events from climate change could adversely impact birth weight and vary by SES.

  6. Climate Change Impact on Hydrological Extremes: Preliminary Results from the Polish-Norwegian Project

    NASA Astrophysics Data System (ADS)

    Romanowicz, Renata J.; Bogdanowicz, Ewa; Debele, Sisay E.; Doroszkiewicz, Joanna; Hisdal, Hege; Lawrence, Deborah; Meresa, Hadush K.; Napiórkowski, Jarosław J.; Osuch, Marzena; Strupczewski, Witold G.; Wilson, Donna; Wong, Wai Kwok

    2016-04-01

    This paper presents the background, objectives, and preliminary outcomes from the first year of activities of the Polish-Norwegian project CHIHE (Climate Change Impact on Hydrological Extremes). The project aims to estimate the influence of climate changes on extreme river flows (low and high) and to evaluate the impact on the frequency of occurrence of hydrological extremes. Eight "twinned" catchments in Poland and Norway serve as case studies. We present the procedures of the catchment selection applied in Norway and Poland and a database consisting of near-natural ten Polish and eight Norwegian catchments constructed for the purpose of climate impact assessment. Climate projections for selected catchments are described and compared with observations of temperature and precipitation available for the reference period. Future changes based on those projections are analysed and assessed for two periods, the near future (2021-2050) and the far-future (2071-2100). The results indicate increases in precipitation and temperature in the periods and regions studied both in Poland and Norway.

  7. Impacts of climate change on rainfall extremes and urban drainage systems: a review.

    PubMed

    Arnbjerg-Nielsen, K; Willems, P; Olsson, J; Beecham, S; Pathirana, A; Bülow Gregersen, I; Madsen, H; Nguyen, V-T-V

    2013-01-01

    A review is made of current methods for assessing future changes in urban rainfall extremes and their effects on urban drainage systems, due to anthropogenic-induced climate change. The review concludes that in spite of significant advances there are still many limitations in our understanding of how to describe precipitation patterns in a changing climate in order to design and operate urban drainage infrastructure. Climate change may well be the driver that ensures that changes in urban drainage paradigms are identified and suitable solutions implemented. Design and optimization of urban drainage infrastructure considering climate change impacts and co-optimizing these with other objectives will become ever more important to keep our cities habitable into the future.

  8. Adaptation Strategies of Soil and Water Conservation in Taiwan for Extreme Climate

    NASA Astrophysics Data System (ADS)

    Huang, Wen-Cheng; Lin, Cheng-Yu; Hsieh, Ting-Ju

    2016-04-01

    Due to global climate change, the impact caused by extreme climate has become more and more compelling. In Taiwan, the total rainfall stays in the same level, but it brings along changes to rain types. The rainfall with high recurrence interval happens frequently, leading to soil loss of slope-land, and it may further result in flooding and sediment hazards. Although Taiwan is a small island, the population density is ranked at the second highest around the world. Moreover, third-fourth of Taiwan is slope-land, so the soil and water conservation is rather important. This study is based on the international trend analysis approach to review the related researches worldwide and 264 research projects in Taiwan. It indicates that under the pressure of extreme climate and social economic changes, it has higher possibility of slope-land to face the impacts from extreme rainfall events, and meanwhile, the carrying capacity of slope-land is decreasing. The experts' brainstorming meetings were held three times, and it concluded the current problems of soil and water conservation and the goal in 2025 for sustainable resources. Also, the 20-year weather data set was adopted to screen out 3 key watersheds with the potential of flooding (Puzih River Watershed), droughts (Xindian River Watershed), and sediment hazards (Chishan River Watershed) according to the moisture index, and further, to propose countermeasures in order to realize the goal in 2025, which is "regarding to climate and socioeconomic changes, it is based on multiple use to manage watershed resources for avoiding disasters and sustaining soil and water conservation." Keyword: Extreme climate, International trend analysis, Brainstorming, Key watershed

  9. Back to the Future -Precipitation Extremes, Climate Variability, Environmental Planning and Adaptation

    NASA Astrophysics Data System (ADS)

    Barros, A. P.

    2008-12-01

    --"The last major climatic oscillation peak was about 1856, or 74 years ago. Practically all of our important railroad and public highway work has been done since that time. Most of our parks systems driveways, and roads of all type for auto travel, in the various States, have been completed within the past 30 years, namely, beginning at the very lowest point of our climatic swing (1900-1910). There is every reason to believe, therefore, as the next 20 years comes on apace, we will witness considerable damage to work done during the past regime of weather."-- Schuman, 1931 At the beginning of the 21st century, as at the beginning of the 20th century, the fundamental question is whether the nation is more prepared for natural disasters today than it was eight decades ago. Indeed, the question is whether the best science, engineering and policy tools are in place to prepare for and respond to extreme events. Changes in the risk and magnitude of extreme precipitation events rank among the most studied impacts, and indicators (symptoms) of climatic variations. Extreme precipitation translates generally into extreme flooding, landslides, collapse of lifeline infrastructure, and the breakdown of public health services among others. In approaching the problem of quantifying the risk and magnitude of extreme precipitation events, there are two major challenges: 1) it is difficult to characterize "observed" (20th century) conditions due to the lack of long-term observations - i.e., short and incomplete historical records; and 2) it is difficult to characterize "predicted" (21st century) conditions due to the lack of skill of precipitation forecasts at spatial and temporal scales meaningful for impact studies, and the short-duration of climate model simulations themselves. The first challenge translates in estimating the probability of occurrence (rare) and magnitude (very large) of events that may have not happened yet. The second challenge is that of quantifying

  10. Climate engineering of vegetated land for hot extremes mitigation: An Earth system model sensitivity study

    NASA Astrophysics Data System (ADS)

    Wilhelm, Micah; Davin, Edouard L.; Seneviratne, Sonia I.

    2015-04-01

    Various climate engineering schemes have been proposed as a way to curb anthropogenic climate change. Land climate engineering schemes aiming to reduce the amount of solar radiation absorbed at the surface by changes in land surface albedo have been considered in a limited number of investigations. However, global studies on this topic have generally focused on the impacts on mean climate rather than extremes. Here we present the results of a series of transient global climate engineering sensitivity experiments performed with the Community Earth System Model over the time period 1950-2100 under historical and Representative Concentration Pathway 8.5 scenarios. Four sets of experiments are performed in which the surface albedo over snow-free vegetated grid points is increased respectively by 0.05, 0.10, 0.15, and 0.20. The simulations show a preferential cooling of hot extremes relative to mean temperatures throughout the Northern midlatitudes during boreal summer under the late twentieth century conditions. Two main mechanisms drive this response: On the one hand, a stronger efficacy of the albedo-induced radiative forcing on days with high incoming shortwave radiation and, on the other hand, enhanced soil moisture-induced evaporative cooling during the warmest days relative to the control simulation due to accumulated soil moisture storage and reduced drying. The latter effect is dominant in summer in midlatitude regions and also implies a reduction of summer drought conditions. It thus constitutes another important benefit of surface albedo modifications in reducing climate change impacts. The simulated response for the end of the 21st century conditions is of the same sign as that for the end of the twentieth century conditions but indicates an increasing absolute impact of land surface albedo increases in reducing mean and extreme temperatures under enhanced greenhouse gas forcing.

  11. Assessing the impact of future climate extremes on the US corn and soybean production

    NASA Astrophysics Data System (ADS)

    Jin, Z.

    2015-12-01

    Future climate changes will place big challenges to the US agricultural system, among which increasing heat stress and precipitation variability were the two major concerns. Reliable prediction of crop productions in response to the increasingly frequent and severe extreme climate is a prerequisite for developing adaptive strategies on agricultural risk management. However, the progress has been slow on quantifying the uncertainty of computational predictions at high spatial resolutions. Here we assessed the risks of future climate extremes on the US corn and soybean production using the Agricultural Production System sIMulator (APSIM) model under different climate scenarios. To quantify the uncertainty due to conceptual representations of heat, drought and flooding stress in crop models, we proposed a new strategy of algorithm ensemble in which different methods for simulating crop responses to those extreme climatic events were incorporated into the APSIM. This strategy allowed us to isolate irrelevant structure differences among existing crop models but only focus on the process of interest. Future climate inputs were derived from high-spatial-resolution (12km × 12km) Weather Research and Forecasting (WRF) simulations under Representative Concentration Pathways 4.5 (RCP 4.5) and 8.5 (RCP 8.5). Based on crop model simulations, we analyzed the magnitude and frequency of heat, drought and flooding stress for the 21st century. We also evaluated the water use efficiency and water deficit on regional scales if farmers were to boost their yield by applying more fertilizers. Finally we proposed spatially explicit adaptation strategies of irrigation and fertilizing for different management zones.

  12. Evaluation of Multiple Regional Climate Models for Summer Extremes of Temperature and Precipitation over East Asia

    NASA Astrophysics Data System (ADS)

    Park, Changyong; Min, Seung-Ki

    2014-05-01

    The regional climate models (RCMs) have been widely used to generate more detailed information in space and time of climate patterns produced by the global climate models (GCMs). Recently the international collaborative effort has been set up as the CORDEX (Coordinated Regional Climate Downscaling Experiment) project which covers several regional domains including East Asia. In this study, five RCMs (HadGEM3-RA, RegCM4, SNU-MM5, SNU-WRF, and YSU-RSM) participating in the CORDEX-East Asia project are evaluated in terms of their skills at simulating climatology of summer extremes. We examine bias and RMSE and conduct a Taylor diagram analysis using seasonal maxima of daily mean temperature and daily precipitation amount over the East Asia land area from 'historical' experiments of individual RCMs and their multi-model ensemble means (MME). The APHRODITE (Asian Precipitation-Highly-Resolved Observational Data Integration Toward Evaluation) datasets on 0.5° x 0.5° grids are used as observations. Results show similar systematic bias patterns between seasonal means and extremes. A cold bias is found along the coast while a warm bias occurs in the northern China. Overall wet bias appears in East Asia but there is a substantial dry bias in South Korea. This dry bias appears related to be a cold SST (sea surface temperature) around South Korea, positioning the monsoonal front (Changma) further south than observations. Taylor diagram analyses show that temperature has better skill in means than in extremes because of higher spatial correlation whereas precipitation exhibits better skill in extremes than in means due to better spatial variability. The latter implies that extreme rainfall events may be better captured although seasonal mean precipitation tends to be overestimated by RCMs. The model performances between mean and extreme are found to be closely related, but not clearly between temperature and precipitation. Temperatures are always better simulated than

  13. Large-scale Agroecosytem's Resiliency to Extreme Hydrometeorological and Climate Extreme Events in the Missouri River Basin

    NASA Astrophysics Data System (ADS)

    Munoz-Arriola, F.; Smith, K.; Corzo, G.; Chacon, J.; Carrillo-Cruz, C.

    2015-12-01

    A major challenge for water, energy and food security relies on the capability of agroecosyststems and ecosystems to adapt to a changing climate and land use changes. The interdependency of these forcings, understood through our ability to monitor and model processes across scales, indicate the "depth" of their impact on agroecosystems and ecosystems, and consequently our ability to predict the system's ability to return to a "normal" state. We are particularly interested in explore two questions: (1) how hydrometeorological and climate extreme events (HCEs) affect sub-seasonal to interannual changes in evapotranspiration and soil moisture? And (2) how agroecosystems recover from the effect of such events. To address those questions we use the land surface hydrologic Variable Infiltration Capacity (VIC) model and the Moderate Resolution Imaging Spectrometer-Leaf Area Index (MODIS-LAI) over two time spans (1950-2013 using a seasonal fixed LAI cycle) and 2001-2013 (an 8-day MODIS-LAI). VIC is forced by daily/16th degree resolution precipitation, minimum and maximum temperature, and wind speed. In this large-scale experiment, resiliency is defined by the capacity of a particular agroecosystem, represented by a grid cell's ET, SM, and LAI to return to a historical average. This broad, yet simplistic definition will contribute to identify the possible components and their scales involved in agroecosystems and ecosystems capacity to adapt to the incidence of HCEs and technologies used to intensify agriculture and diversify their use for food and energy production. Preliminary results show that dynamical changes in land use, tracked by MODIS data, require larger time spans to address properly the influence of technologic improvements in crop production as well as the competition for land for biofuel vs. food production. On the other hand, fixed seasonal changes in land use allow us just to identify hydrologic changes mainly due to climate variability.

  14. Variability of carbon and water fluxes following climate extremes over a tropical forest in southwestern Amazonia.

    PubMed

    Zeri, Marcelo; Sá, Leonardo D A; Manzi, Antônio O; Araújo, Alessandro C; Aguiar, Renata G; von Randow, Celso; Sampaio, Gilvan; Cardoso, Fernando L; Nobre, Carlos A

    2014-01-01

    The carbon and water cycles for a southwestern Amazonian forest site were investigated using the longest time series of fluxes of CO2 and water vapor ever reported for this site. The period from 2004 to 2010 included two severe droughts (2005 and 2010) and a flooding year (2009). The effects of such climate extremes were detected in annual sums of fluxes as well as in other components of the carbon and water cycles, such as gross primary production and water use efficiency. Gap-filling and flux-partitioning were applied in order to fill gaps due to missing data, and errors analysis made it possible to infer the uncertainty on the carbon balance. Overall, the site was found to have a net carbon uptake of ≈5 t C ha(-1) year(-1), but the effects of the drought of 2005 were still noticed in 2006, when the climate disturbance caused the site to become a net source of carbon to the atmosphere. Different regions of the Amazon forest might respond differently to climate extremes due to differences in dry season length, annual precipitation, species compositions, albedo and soil type. Longer time series of fluxes measured over several locations are required to better characterize the effects of climate anomalies on the carbon and water balances for the whole Amazon region. Such valuable datasets can also be used to calibrate biogeochemical models and infer on future scenarios of the Amazon forest carbon balance under the influence of climate change. PMID:24558378

  15. Variability of carbon and water fluxes following climate extremes over a tropical forest in southwestern Amazonia.

    PubMed

    Zeri, Marcelo; Sá, Leonardo D A; Manzi, Antônio O; Araújo, Alessandro C; Aguiar, Renata G; von Randow, Celso; Sampaio, Gilvan; Cardoso, Fernando L; Nobre, Carlos A

    2014-01-01

    The carbon and water cycles for a southwestern Amazonian forest site were investigated using the longest time series of fluxes of CO2 and water vapor ever reported for this site. The period from 2004 to 2010 included two severe droughts (2005 and 2010) and a flooding year (2009). The effects of such climate extremes were detected in annual sums of fluxes as well as in other components of the carbon and water cycles, such as gross primary production and water use efficiency. Gap-filling and flux-partitioning were applied in order to fill gaps due to missing data, and errors analysis made it possible to infer the uncertainty on the carbon balance. Overall, the site was found to have a net carbon uptake of ≈5 t C ha(-1) year(-1), but the effects of the drought of 2005 were still noticed in 2006, when the climate disturbance caused the site to become a net source of carbon to the atmosphere. Different regions of the Amazon forest might respond differently to climate extremes due to differences in dry season length, annual precipitation, species compositions, albedo and soil type. Longer time series of fluxes measured over several locations are required to better characterize the effects of climate anomalies on the carbon and water balances for the whole Amazon region. Such valuable datasets can also be used to calibrate biogeochemical models and infer on future scenarios of the Amazon forest carbon balance under the influence of climate change.

  16. Variability of Carbon and Water Fluxes Following Climate Extremes over a Tropical Forest in Southwestern Amazonia

    PubMed Central

    Zeri, Marcelo; Sá, Leonardo D. A.; Manzi, Antônio O.; Araújo, Alessandro C.; Aguiar, Renata G.; von Randow, Celso; Sampaio, Gilvan; Cardoso, Fernando L.; Nobre, Carlos A.

    2014-01-01

    The carbon and water cycles for a southwestern Amazonian forest site were investigated using the longest time series of fluxes of CO2 and water vapor ever reported for this site. The period from 2004 to 2010 included two severe droughts (2005 and 2010) and a flooding year (2009). The effects of such climate extremes were detected in annual sums of fluxes as well as in other components of the carbon and water cycles, such as gross primary production and water use efficiency. Gap-filling and flux-partitioning were applied in order to fill gaps due to missing data, and errors analysis made it possible to infer the uncertainty on the carbon balance. Overall, the site was found to have a net carbon uptake of ≈5 t C ha−1 year−1, but the effects of the drought of 2005 were still noticed in 2006, when the climate disturbance caused the site to become a net source of carbon to the atmosphere. Different regions of the Amazon forest might respond differently to climate extremes due to differences in dry season length, annual precipitation, species compositions, albedo and soil type. Longer time series of fluxes measured over several locations are required to better characterize the effects of climate anomalies on the carbon and water balances for the whole Amazon region. Such valuable datasets can also be used to calibrate biogeochemical models and infer on future scenarios of the Amazon forest carbon balance under the influence of climate change. PMID:24558378

  17. Climate Variability and Weather Extremes: Model-Simulated and Historical Data. Chapter 9

    NASA Technical Reports Server (NTRS)

    Schubert, Siegfried D.; Lim, Young-Kwon

    2012-01-01

    Extremes in weather and climate encompass a wide array of phenomena including tropical storms, mesoscale convective systems, snowstorms, floods, heat waves, and drought. Understanding how such extremes might change in the future requires an understanding of their past behavior including their connections to large-scale climate variability and trends. Previous studies suggest that the most robust findings concerning changes in short-term extremes are those that can be most directly (though not completely) tied to the increase in the global mean temperatures. These include the findings that (IPCC 2007): There has been a widespread reduction in the number of frost days in mid-latitude regions in recent decades, an increase in the number of warm extremes, particularly warm nights, and a reduction in the number of cold extremes, particularly cold nights. For North America in particular (CCSP SAP 3.3, 2008): There are fewer unusually cold days during the last few decades. The last 10 years have seen a lower number of severe cold waves than for any other 10-year period in the historical record that dates back to 1895. There has been a decrease in the number of frost days and a lengthening of the frost-free season, particularly in the western part of North America. Other aspects of extremes such as the changes in storminess have a less clear signature of long term change, with considerable interannual, and decadal variability that can obscure any climate change signal. Nevertheless, regarding extratropical storms (CCSP SAP 3.3, 2008): The balance of evidence suggests that there has been a northward shift in the tracks of strong low pressure systems (storms) in both the North Atlantic and North Pacific basins. For North America: Regional analyses suggest that there has been a decrease in snowstorms in the South and lower Midwest of the United States, and an increase in snowstorms in the upper Midwest and Northeast. Despite the progress already made, our understanding of the

  18. Hydrologic Extremes in a changing climate: how much information can regional climate models provide?

    SciTech Connect

    Lettenmaier, Dennis P.

    2012-08-14

    We proposed to identify a set of about 10 urban areas across the western U.S., and hourly precipitation data within each of these areas, which were extracted from the NCDC TD 3240. We also proposed to analyze the annual maximum series of precipitation extremes simulated for NARCCAP (using Reanalysis boundary forcing) for the grid cells close to station data, and to compare the distributions of annual maximum precipitation for accumulation intervals ranging from one to 28 hours. Recognizing that there may inevitably be differences between the station data and RCM grid cell values, we proposed to examine the scale dependence in the distributions of extremes.

  19. Ecosystem resilience despite large-scale altered hydro climatic conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Climate change is predicted to increase both drought frequency and duration, and when coupled with substantial warming, will establish a new hydroclimatological paradigm for many regions. Large-scale, warm droughts have recently impacted North America, Africa, Europe, Amazonia, and Australia result...

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

    NASA Astrophysics Data System (ADS)

    Aziz, F.

    2015-12-01

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

  1. Precipitation extremes over La Plata Basin - Review and new results from observations and climate simulations

    NASA Astrophysics Data System (ADS)

    Cavalcanti, I. F. A.; Carril, A. F.; Penalba, O. C.; Grimm, A. M.; Menéndez, C. G.; Sanchez, E.; Cherchi, A.; Sörensson, A.; Robledo, F.; Rivera, J.; Pántano, V.; Bettolli, L. M.; Zaninelli, P.; Zamboni, L.; Tedeschi, R. G.; Dominguez, M.; Ruscica, R.; Flach, R.

    2015-04-01

    Monthly and daily precipitation extremes over La Plata Basin (LPB) are analyzed in the framework of the CLARIS-LPB Project. A review of the studies developed during the project and results of additional research are presented and discussed. Specific aspects of analysis are focused on large-scale versus local processes impacts on the intensity and frequency of precipitation extremes over LPB, and on the assessment of specific wet and dry spell indices and their changed characteristics in future climate scenarios. The analysis is shown for both available observations of precipitation in the region and ad-hoc global and regional models experiments. The Pacific, Indian and Atlantic Oceans can all impact precipitation intensity and frequency over LPB. In particular, considering the Pacific sector, different types of ENSO events (i.e. canonical vs Modoki or East vs Central) have different influences. Moreover, model projections indicate an increase in the frequency of precipitation extremes over LPB during El Niño and La Ninã events in future climate. Local forcings can also be important for precipitation extremes. Here, the feedbacks between soil moisture and extreme precipitation in LPB are discussed based on hydric conditions in the region and model sensitivity experiments. Concerning droughts, it was found that they were more frequent in the western than in the eastern sector of LPB during the period of 1962-2008. On the other hand, observations and model experiments agree in that the monthly wet extremes were more frequent than the dry extremes in the northern and southern LPB sectors during the period 1979-2001, with higher frequency in the south.

  2. Attributing Human Mortality During Extreme Heat Waves to Anthropogenic Climate Change

    NASA Astrophysics Data System (ADS)

    Mitchell, D.; Heaviside, C.; Vardoulakis, S.; Huntingford, C.; Masato, G.; Guillod, B. P.; Frumhoff, P. C.; Bowery, A.; Allen, M. R.

    2015-12-01

    Climate change is the biggest global health threat of the 21st century (Costello et al, 2009; Watts et al, 2015). Perhaps one of the clearest examples of this is the summer heat wave of 2003, which saw up to seventy thousand excess deaths across Europe (Robine et al, 2007). The extreme temperatures are now thought to be significantly enhanced due to anthropogenic climate change (Stott et al, 2004; Christidis et al, 2015). Here, we consider not only the Europe-wide temperature response of the heat wave, but the localised response using a high-resolution regional model simulating 2003 climate conditions thousands of times. For the first time, by employing end-to-end attribution, we attribute changes in mortality to the increased radiative forcing from climate change, with a specific focus on London and Paris. We show that in both cities, a sizable proportion of the excess mortality can be attributed to human emissions. With European heat waves projected to increase into the future, these results provide a worrying reality for what may lie ahead. Christidis, Nikolaos, Gareth S. Jones, and Peter A. Stott. "Dramatically increasing chance of extremely hot summers since the 2003 European heatwave." Nature Climate Change (2014). Costello, Anthony, et al. "Managing the health effects of climate change: lancet and University College London Institute for Global Health Commission." The Lancet 373.9676 (2009): 1693-1733. Stott, Peter A., Dáithí A. Stone, and Myles R. Allen. "Human contribution to the European heatwave of 2003." Nature 432.7017 (2004): 610-614 Watts, N., et al. "Health and climate change: policy responses to protect public health." Lancet. 2015.

  3. Variability of extreme climate events in the territory and water area of Russia

    NASA Astrophysics Data System (ADS)

    Serykh, Ilya; Kostianoy, Andrey

    2016-04-01

    The Fourth (2007) and Fifth (2014) Assessment Reports on Climate Change of the Intergovernmental Panel on Climate Change (IPCC) state that in the XXI century, climate change will be accompanied by an increase in the frequency, intensity and duration of extreme nature events such as: extreme precipitation and extreme high and low air temperatures. All these will lead to floods, droughts, fires, shallowing of rivers, lakes and water reservoirs, desertification, dust storms, melting of glaciers and permafrost, algal bloom events in the seas, lakes and water reservoirs. In its turn, these events will lead to chemical and biological contamination of water, land and air. These events will result in a deterioration of quality of life, significant financial loss due to damage to the houses, businesses, roads, agriculture, forestry, tourism, and in many cases they end in loss of life. These predictions are confirmed by the results of the studies presented in the RosHydromet First (2008) and Second (2014) Assessment Reports on Climate Change and its Consequences in Russian Federation. Scientists predictions have been repeatedly confirmed in the last 15 years - floods in Novorossiysk (2002), Krymsk and Gelendzhik (2012), the Far East (2013), heat waves in 2010, unusually cold winter (February) of 2012 and unusually warm winter of 2013/2014 in the European territory of Russia. In this regard, analysis and forecasting of extreme climate events associated with climate change in the territory of Russia are an extremely important task. This task is complicated by the fact that modern atmospheric models used by IPCC and RosHydromet badly reproduce and predict the intensity of precipitation. We are analyzing meteorological reanalysis data (NCEP/NCAR, 20th Century Reanalysis, ERA-20C, JRA-55) and satellite data (NASA and AVISO) on air, water and land temperature, rainfall, wind speed and cloud cover, water levels in seas and lakes, index of vegetation over the past 30-60 years

  4. Understanding the Impacts of Climate and Hydrologic Extremes on Diarrheal Diseases in Southwestern Amazon

    NASA Astrophysics Data System (ADS)

    Fonseca, P. A. M.

    2015-12-01

    Bacterial diarrheal diseases have a high incidence rate during and after flooding episodes. In the Brazilian Amazon, flood extreme events have become more frequent, leading to high incidence rates for infant diarrhea. In this study we aimed to find a statistical association between rainfall, river levels and diarrheal diseases in children under 5, in the river Acre basin, in the State of Acre (Brazil). We also aimed to identify the time-lag and annual season of extreme rainfall and flooding in different cities in the water basin. The results using Tropical Rainfall Measuring Mission (TRMM) Satellite rainfall data show robustness of these estimates against observational stations on-ground. The Pearson coefficient correlation results (highest 0.35) indicate a time-lag, up to 4 days in three of the cities in the water-basin. In addition, a correlation was also tested between monthly accumulated rainfall and the diarrheal incidence during the rainy season (DJF). Correlation results were higher, especially in Acrelândia (0.7) and Brasiléia and Epitaciolândia (0.5). The correlation between water level monthly averages and diarrheal diseases incidence was 0.3 and 0.5 in Brasiléia and Epitaciolândia. The time-lag evidence found in this paper is critical to inform stakeholders, local populations and civil defense authorities about the time available for preventive and adaptation measures between extreme rainfall and flooding events in vulnerable cities. This study was part of a pilot application in the state of Acre of the PULSE-Brazil project (http://www.pulse-brasil.org/tool/), an interface of climate, environmental and health data to support climate adaptation. The next step of this research is to expand the analysis to other climate variables on diarrheal diseases across the whole Brazilian Amazon Basin and estimate the relative risk (RR) of a child getting sick. A statistical model will estimate RR based on the observed values and seasonal forecasts (higher

  5. Potential Geomorphic Consequences of Wave Climate Alterations along Cuspate Coastlines

    NASA Astrophysics Data System (ADS)

    Johnson, J.; Moore, L. J.; Ells, K. D.; Murray, A.

    2012-12-01

    While much attention has been given to the effects of sea level rise on coastal environments, changes in wave climate (in response to predicted increases in tropical storm intensity) may also significantly impact coastal areas in the future. Characterized by rapid alongshore shifts in shoreline orientation, cuspate coastlines are particularly sensitive to changes in wave climate and thus represent the best type of coastline for detecting initial responses to changing wave conditions. Previous work indicates that Cape Hatteras and Cape Lookout, NC have become increasingly asymmetric in response to an increase in Atlantic summer wave heights identified by Komar and Allen (2007). Here, we contrast historic and recent patterns of erosion and accretion for areas surrounding Cape Fear, NC and Fishing Point, VA to determine if a similar coastline response can be detected for a location heavily impacted by shoreline stabilization efforts and a location experiencing a less-pronounced trend of increasing wave energy, respectively. We obtained shorelines from NOAA, the USGS, and the North Carolina Department of Natural Resources and used the Digital Shoreline Analysis System (DSAS) to calculate shoreline change rates for historic (pre-1975) and recent (post-1975) time periods. The 1975 breakpoint was chosen to correspond with the timing of reported increases in hurricane-generated (summer) wave heights. Initial results suggest that the influence of shoreline stabilization efforts (primarily beach nourishment, one jetty and a few groins) has overwhelmed any wave-climate change response that may otherwise have been detectable surrounding Cape Fear, NC. Preliminary results for Fishing Point, VA indicate no discernible wave-climate related trend in shoreline change, suggesting that wave climate changes have not been of a significant magnitude to significantly influence patterns of erosion and accretion along this stretch of coastline. Coastline Evolution Model (CEM) simulations

  6. Evaluating regional climate models for simulating sub-daily rainfall extremes

    NASA Astrophysics Data System (ADS)

    Cortés-Hernández, Virginia Edith; Zheng, Feifei; Evans, Jason; Lambert, Martin; Sharma, Ashish; Westra, Seth

    2016-09-01

    Sub-daily rainfall extremes are of significant societal interest, with implications for flash flooding and the design of urban stormwater systems. It is increasingly recognised that extreme subdaily rainfall will intensify as a result of global temperature increases, with regional climate models (RCMs) representing one of the principal lines of evidence on the likely magnitude and spatiotemporal characteristics of these changes. To evaluate the ability of RCMs to simulate subdaily extremes, it is common to compare the simulated statistical characteristics of the extreme rainfall events with those from observational records. While such analyses are important, they provide insufficient insight into whether the RCM reproduces the correct underlying physical processes; in other words, whether the model "gets the right answers for the right reasons". This paper develops a range of metrics to assess the performance of RCMs in capturing the physical mechanisms that produce extreme rainfall. These metrics include the diurnal and seasonal cycles, relationship between rainfall intensity and temperature, temporal scaling, and the spatial structure of extreme rainfall events. We evaluate a high resolution RCM—the Weather Research Forecasting model—over the Greater Sydney region, using three alternative parametrization schemes. The model shows consistency with the observations for most of the proposed metrics. Where differences exist, these are dependent on both the rainfall duration and model parameterization strategy. The use of physically meaningful performance metrics not only enhances the confidence in model simulations, but also provides better diagnostic power to assist with future model improvement.

  7. The analyses of extreme climate events over China based on CMIP5 historical and future simulations

    NASA Astrophysics Data System (ADS)

    Yang, S.; Dong, W.; Feng, J.; Chou, J.

    2013-12-01

    The extreme climate events have a serious influence on human society. Based on observations and 12 simulations from Coupled Model Intercomparison Project Phase 5 (CMIP5), Climatic extremes and their changes over china in history and future scenarios of three Representative Concentration Pathways (RCPs) are analyzed. Because of the background of global warming, in observations, the frost days (FD) and low-temperature threshold days (TN10P) have decreasing trend, and summer days (SU), high-temperature threshold days (TX90P), the heavy precipitation days (R20) and contribution of heavy precipitation days (P95T) show an increasing trend. Most coupled models can basically simulate main characteristics of most extreme indexes. The models reproduce the mean FD and TX90P value best and can give basic trends of the FD, TN10P, SU and TX90P. High correlation coefficients between simulated results and observation are found in FD, SU and P95T. For FD and SU index, most of the models have good ability to capture the spatial differences between the mean state of the 1986-2005 and 1961-1980 periods, but for other indexes, most of models' simulation ability for spatial disparity are not so satisfactory and have to be promoted. Under the high emission scenario of RCP8.5, the century-scale linear changes of Multi-Model Ensembles (MME) for FD, SU, TN10P, TX90P, R20 and P95T are -46.9, 46.0, -27.1, 175.4, 2.9 days and 9.9%, respectively. Due to the complexities of physical process parameterizations and the limitation of forcing data, a large uncertainty still exists in the simulations of climatic extremes. Fig.1 Observed and modeled multi-year average for each index (Dotted line: observation) Table1. Extreme index definition

  8. Influences of extreme weather, climate and pesticide use on invertebrates in cereal fields over 42 years.

    PubMed

    Ewald, Julie A; Wheatley, Christopher J; Aebischer, Nicholas J; Moreby, Stephen J; Duffield, Simon J; Crick, Humphrey Q P; Morecroft, Michael B

    2015-11-01

    Cereal fields are central to balancing food production and environmental health in the face of climate change. Within them, invertebrates provide key ecosystem services. Using 42 years of monitoring data collected in southern England, we investigated the sensitivity and resilience of invertebrates in cereal fields to extreme weather events and examined the effect of long-term changes in temperature, rainfall and pesticide use on invertebrate abundance. Of the 26 invertebrate groups examined, eleven proved sensitive to extreme weather events. Average abundance increased in hot/dry years and decreased in cold/wet years for Araneae, Cicadellidae, adult Heteroptera, Thysanoptera, Braconidae, Enicmus and Lathridiidae. The average abundance of Delphacidae, Cryptophagidae and Mycetophilidae increased in both hot/dry and cold/wet years relative to other years. The abundance of all 10 groups usually returned to their long-term trend within a year after the extreme event. For five of them, sensitivity to cold/wet events was lowest (translating into higher abundances) at locations with a westerly aspect. Some long-term trends in invertebrate abundance correlated with temperature and rainfall, indicating that climate change may affect them. However, pesticide use was more important in explaining the trends, suggesting that reduced pesticide use would mitigate the effects of climate change. PMID:26149473

  9. Has the Temperature Climate of the United States Become More Extreme?

    NASA Astrophysics Data System (ADS)

    Stevens, L. E.; Kunkel, K.; Vose, R. S.; Knight, R. W.

    2014-12-01

    Extreme heat has affected parts of the United States during recent summers, particularly 2011 and 2012. Severe cold has also occurred in recent years. This has created a perception that the temperature climate of the U.S. has become more extreme. Is this the case? We address this question by computing probability distribution functions (PDFs) for each season and evaluating temporal changes for the 20th and early 21st centuries using a new gridded monthly temperature data set. We examine changes in the mean, width, and shape of the PDFs for seven U.S. regions, as defined in the third National Climate Assessment. During the past 2-3 decades, there has been a shift toward more frequent very warm months, but this has been accompanied by a decrease in the occurrence of very cold months. Thus, overall we determine that the temperature climate of the U.S. has not become more extreme. The 1930s were an earlier period of frequent very warm months, but this was primarily a result of very warm daytime temperatures, while the occurrence of months with very high nighttime temperatures was not unusually large during that period. There are important regional variations in these results. In particular, the shift to more frequent very warm months is not predominant in the southeast U.S. annually or in parts of the central U.S. in the summer. This lack of warming is a feature of daytime maximum temperature, not nighttime minimum temperature.

  10. Influences of extreme weather, climate and pesticide use on invertebrates in cereal fields over 42 years.

    PubMed

    Ewald, Julie A; Wheatley, Christopher J; Aebischer, Nicholas J; Moreby, Stephen J; Duffield, Simon J; Crick, Humphrey Q P; Morecroft, Michael B

    2015-11-01

    Cereal fields are central to balancing food production and environmental health in the face of climate change. Within them, invertebrates provide key ecosystem services. Using 42 years of monitoring data collected in southern England, we investigated the sensitivity and resilience of invertebrates in cereal fields to extreme weather events and examined the effect of long-term changes in temperature, rainfall and pesticide use on invertebrate abundance. Of the 26 invertebrate groups examined, eleven proved sensitive to extreme weather events. Average abundance increased in hot/dry years and decreased in cold/wet years for Araneae, Cicadellidae, adult Heteroptera, Thysanoptera, Braconidae, Enicmus and Lathridiidae. The average abundance of Delphacidae, Cryptophagidae and Mycetophilidae increased in both hot/dry and cold/wet years relative to other years. The abundance of all 10 groups usually returned to their long-term trend within a year after the extreme event. For five of them, sensitivity to cold/wet events was lowest (translating into higher abundances) at locations with a westerly aspect. Some long-term trends in invertebrate abundance correlated with temperature and rainfall, indicating that climate change may affect them. However, pesticide use was more important in explaining the trends, suggesting that reduced pesticide use would mitigate the effects of climate change.

  11. Influence of Climate Extremes and Land Use on Fecal Contamination of Shallow Tubewells in Bangladesh.

    PubMed

    Wu, Jianyong; Yunus, Mohammad; Islam, Md Sirajul; Emch, Michael

    2016-03-01

    Climate extremes in conjunction with some land use practices are expected to have large impacts on water quality. However, the impacts of land use and climate change on fecal contamination of groundwater has not been well characterized. This work quantifies the influences of extreme weather events and land use practices on Escherichia coli presence and concentration in groundwater from 125 shallow wells, a dominant drinking water resource in rural Bangladesh, monitored over a 17 month period. The results showed that E. coli presence was significantly associated with the number of heavy rain days, developed land and areas with more surface water. These variables also had significant impacts on E. coli concentration, with risk ratios of 1.38 (95% CI = 1.16, 1.65), 1.07 (95% CI: 1.05, 1.09), and 1.02 (95% CI = 1.01, 1.03), respectively. Significant synergistic effects on E. coli presence and concentration were observed when land use and weather variables were combined. The findings suggest that climate extremes and land use practices, particularly urbanization, might promote fecal contamination of shallow well water, thus increasing the risk of diarrheal diseases.

  12. Influence of Climate Extremes and Land Use on Fecal Contamination of Shallow Tubewells in Bangladesh.

    PubMed

    Wu, Jianyong; Yunus, Mohammad; Islam, Md Sirajul; Emch, Michael

    2016-03-01

    Climate extremes in conjunction with some land use practices are expected to have large impacts on water quality. However, the impacts of land use and climate change on fecal contamination of groundwater has not been well characterized. This work quantifies the influences of extreme weather events and land use practices on Escherichia coli presence and concentration in groundwater from 125 shallow wells, a dominant drinking water resource in rural Bangladesh, monitored over a 17 month period. The results showed that E. coli presence was significantly associated with the number of heavy rain days, developed land and areas with more surface water. These variables also had significant impacts on E. coli concentration, with risk ratios of 1.38 (95% CI = 1.16, 1.65), 1.07 (95% CI: 1.05, 1.09), and 1.02 (95% CI = 1.01, 1.03), respectively. Significant synergistic effects on E. coli presence and concentration were observed when land use and weather variables were combined. The findings suggest that climate extremes and land use practices, particularly urbanization, might promote fecal contamination of shallow well water, thus increasing the risk of diarrheal diseases. PMID:26844955

  13. Quantifying the US Crop Yield in Response to Extreme Climatic Events from 1948 to 2013

    NASA Astrophysics Data System (ADS)

    Jin, Z.; Zhuang, Q.

    2014-12-01

    The increasingly frequent and severe extreme climatic events (ECEs) under climate changes will negatively affect crop productivity and threat the global food security. Reliable forecast of crop yields response to those ECEs is a prerequisite for developing strategies on agricultural risk management. However, the progress of quantifying such responses with ecosystem models has been slow. In this study, we first review existing algorithms of yields response to ECEs among major crops (i.e., Corn, Wheat and Soybean) for the United States from a set of process-based crop models. These algorithms are aggregated into four categories of ECEs: drought, heavy precipitation, extreme heat, and frost. Species-specific ECEs thresholds as tipping point of crop yield response curve are examined. Four constraint scalar functions derived for each category of ECEs are then added to an agricultural ecosystem model, CLM-AG, respectively. The revised model is driven by NCEP/NCAR reanalysis data from 1948 to 2013 to estimate the US major crop yields, and then evaluated with county-level yield statistics from the National Agricultural Statistics Service (NASS). We also include MODIS NPP product as a reference for the period 2001-2013. Our study will help to identify gaps in capturing yield response to ECEs with contemporary crop models, and provide a guide on developing the new generation of crop models to account for the effects of more future extreme climate events.

  14. Using Dynamically Downscaled Climate Model Outputs to Inform Projections of Extreme Precipitation Events

    NASA Technical Reports Server (NTRS)

    Wobus, Cameron; Reynolds, Lara; Jones, Russell; Horton, Radley; Smith, Joel; Fries, J. Stephen; Tryby, Michael; Spero, Tanya; Nolte, Chris

    2015-01-01

    Many of the storms that generate damaging floods are caused by locally intense, sub-daily precipitation, yet the spatial and temporal resolution of the most widely available climate model outputs are both too coarse to simulate these events. Thus there is often a disconnect between the nature of the events that cause damaging floods and the models used to project how climate change might influence their magnitude. This could be a particular problem when developing scenarios to inform future storm water management options under future climate scenarios. In this study we sought to close this gap, using sub-daily outputs from the Weather Research and Forecasting model (WRF) from each of the nine climate regions in the United States. Specifically, we asked 1) whether WRF outputs projected consistent patterns of change for sub-daily and daily precipitation extremes; and 2) whether this dynamically downscaled model projected different magnitudes of change for 3-hourly vs 24-hourly extreme events. We extracted annual maximum values for 3-hour through 24-hour precipitation totals from an 11-year time series of hindcast (1995-2005) and mid-century (2045-2055) climate, and calculated the direction and magnitude of change for 3-hour and 24-hour extreme events over this timeframe. The model results project that the magnitude of both 3-hour and 24-hour events will increase over most regions of the United States, but there was no clear or consistent difference in the relative magnitudes of change for sub-daily vs daily events.

  15. Resolving the life cycle alters expected impacts of climate change.

    PubMed

    Levy, Ofir; Buckley, Lauren B; Keitt, Timothy H; Smith, Colton D; Boateng, Kwasi O; Kumar, Davina S; Angilletta, Michael J

    2015-08-22

    Recent models predict contrasting impacts of climate change on tropical and temperate species, but these models ignore how environmental stress and organismal tolerance change during the life cycle. For example, geographical ranges and extinction risks have been inferred from thermal constraints on activity during the adult stage. Yet, most animals pass through a sessile embryonic stage before reaching adulthood, making them more susceptible to warming climates than current models would suggest. By projecting microclimates at high spatio-temporal resolution and measuring thermal tolerances of embryos, we developed a life cycle model of population dynamics for North American lizards. Our analyses show that previous models dramatically underestimate the demographic impacts of climate change. A predicted loss of fitness in 2% of the USA by 2100 became 35% when considering embryonic performance in response to hourly fluctuations in soil temperature. Most lethal events would have been overlooked if we had ignored thermal stress during embryonic development or had averaged temperatures over time. Therefore, accurate forecasts require detailed knowledge of environmental conditions and thermal tolerances throughout the life cycle.

  16. Resolving the life cycle alters expected impacts of climate change

    PubMed Central

    Levy, Ofir; Buckley, Lauren B.; Keitt, Timothy H.; Smith, Colton D.; Boateng, Kwasi O.; Kumar, Davina S.; Angilletta, Michael J.

    2015-01-01

    Recent models predict contrasting impacts of climate change on tropical and temperate species, but these models ignore how environmental stress and organismal tolerance change during the life cycle. For example, geographical ranges and extinction risks have been inferred from thermal constraints on activity during the adult stage. Yet, most animals pass through a sessile embryonic stage before reaching adulthood, making them more susceptible to warming climates than current models would suggest. By projecting microclimates at high spatio-temporal resolution and measuring thermal tolerances of embryos, we developed a life cycle model of population dynamics for North American lizards. Our analyses show that previous models dramatically underestimate the demographic impacts of climate change. A predicted loss of fitness in 2% of the USA by 2100 became 35% when considering embryonic performance in response to hourly fluctuations in soil temperature. Most lethal events would have been overlooked if we had ignored thermal stress during embryonic development or had averaged temperatures over time. Therefore, accurate forecasts require detailed knowledge of environmental conditions and thermal tolerances throughout the life cycle. PMID:26290072

  17. Decision-support tools for Extreme Weather and Climate Events in the Northeast United States

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Lowery, M.; Whelchel, A.

    2013-12-01

    Decision-support tools were assessed for the 2013 National Climate Assessment technical input document, "Climate Change in the Northeast, A Sourcebook". The assessment included tools designed to generate and deliver actionable information to assist states and highly populated urban and other communities in assessment of climate change vulnerability and risk, quantification of effects, and identification of adaptive strategies in the context of adaptation planning across inter-annual, seasonal and multi-decadal time scales. State-level adaptation planning in the Northeast has generally relied on qualitative vulnerability assessments by expert panels and stakeholders, although some states have undertaken initiatives to develop statewide databases to support vulnerability assessments by urban and local governments, and state agencies. The devastation caused by Superstorm Sandy in October 2012 has raised awareness of the potential for extreme weather events to unprecedented levels and created urgency for action, especially in coastal urban and suburban communities that experienced pronounced impacts - especially in New Jersey, New York and Connecticut. Planning approaches vary, but any adaptation and resiliency planning process must include the following: - Knowledge of the probable change in a climate variable (e.g., precipitation, temperature, sea-level rise) over time or that the climate variable will attain a certain threshold deemed to be significant; - Knowledge of intensity and frequency of climate hazards (past, current or future events or conditions with potential to cause harm) and their relationship with climate variables; - Assessment of climate vulnerabilities (sensitive resources, infrastructure or populations exposed to climate-related hazards); - Assessment of relative risks to vulnerable resources; - Identification and prioritization of adaptive strategies to address risks. Many organizations are developing decision-support tools to assist in the urban

  18. Modelling hydrological extremes under non-stationary conditions using climate covariates

    NASA Astrophysics Data System (ADS)

    Vasiliades, Lampros; Galiatsatou, Panagiota; Loukas, Athanasios

    2013-04-01

    Extreme value theory is a probabilistic theory that can interpret the future probabilities of occurrence of extreme events (e.g. extreme precipitation and streamflow) using past observed records. Traditionally, extreme value theory requires the assumption of temporal stationarity. This assumption implies that the historical patterns of recurrence of extreme events are static over time. However, the hydroclimatic system is nonstationary on time scales that are relevant to extreme value analysis, due to human-mediated and natural environmental change. In this study the generalized extreme value (GEV) distribution is used to assess nonstationarity in annual maximum daily rainfall and streamflow timeseries at selected meteorological and hydrometric stations in Greece and Cyprus. The GEV distribution parameters (location, scale, and shape) are specified as functions of time-varying covariates and estimated using the conditional density network (CDN) as proposed by Cannon (2010). The CDN is a probabilistic extension of the multilayer perceptron neural network. Model parameters are estimated via the generalized maximum likelihood (GML) approach using the quasi-Newton BFGS optimization algorithm, and the appropriate GEV-CDN model architecture for the selected meteorological and hydrometric stations is selected by fitting increasingly complicated models and choosing the one that minimizes the Akaike information criterion with small sample size correction. For all case studies in Greece and Cyprus different formulations are tested with combinational cases of stationary and nonstationary parameters of the GEV distribution, linear and non-linear architecture of the CDN and combinations of the input climatic covariates. Climatic indices such as the Southern Oscillation Index (SOI), which describes atmospheric circulation in the eastern tropical pacific related to El Niño Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO) index that varies on an interdecadal

  19. Intense precipitation extremes in a warmer climate: results from CMIP5 models

    NASA Astrophysics Data System (ADS)

    scoccimarro, enrico; gualdi, silvio; bellucci, alessio; zampieri, matteo; navarra, antonio

    2013-04-01

    In this work the authors investigate possible changes in the intensity of extreme precipitation events under a warmer climate, using the results of a set of 20 climate models taking part to the Coupled Model Intercomparison Project phase 5 effort (CMIP5). Future changes are evaluated as the epoch difference between the last four decades of the 21st and the 20th Century assuming the Representative Concentration Pathway RCP8.5 scenario. As a measure of the intensity associated with extreme precipitation events, we use the difference between the 99th and the 90th percentiles. Despite a slight tendency to underestimate the observed extreme precipitation intensity, the considered CMIP5 models well represent the observed patterns during both summer and winter seasons for the 1997-2005 period. Future changes in average precipitation are consistent with previous findings based on CMIP3 models. CMIP5 models show a projected increase for the end of the twenty-first century of the intensity of the extreme precipitations, particularly pronounced over India, South East Asia, Indonesia and Central Africa during boreal summer, as well as over South America and the southern Africa during boreal winter. These changes are consistent with a strong increase of the column integrated water content availability over the afore mentioned regions.

  20. Preface: Impacts of extreme climate events and disturbances on carbon dynamics

    NASA Astrophysics Data System (ADS)

    Xiao, Jingfeng; Liu, Shuguang; Stoy, Paul C.

    2016-06-01

    The impacts of extreme climate events and disturbances (ECE&D) on the carbon cycle have received growing attention in recent years. This special issue showcases a collection of recent advances in understanding the impacts of ECE&D on carbon cycling. Notable advances include quantifying how harvesting activities impact forest structure, carbon pool dynamics, and recovery processes; observed drastic increases of the concentrations of dissolved organic carbon and dissolved methane in thermokarst lakes in western Siberia during a summer warming event; disentangling the roles of herbivores and fire on forest carbon dioxide flux; direct and indirect impacts of fire on the global carbon balance; and improved atmospheric inversion of regional carbon sources and sinks by incorporating disturbances. Combined, studies herein indicate several major research needs. First, disturbances and extreme events can interact with one another, and it is important to understand their overall impacts and also disentangle their effects on the carbon cycle. Second, current ecosystem models are not skillful enough to correctly simulate the underlying processes and impacts of ECE&D (e.g., tree mortality and carbon consequences). Third, benchmark data characterizing the timing, location, type, and magnitude of disturbances must be systematically created to improve our ability to quantify carbon dynamics over large areas. Finally, improving the representation of ECE&D in regional climate/earth system models and accounting for the resulting feedbacks to climate are essential for understanding the interactions between climate and ecosystem dynamics.

  1. Influence and predictive capacity of climate anomalies on daily to decadal extremes in canopy photosynthesis.

    PubMed

    Desai, Ankur R

    2014-02-01

    Significant advances have been made over the past decades in capabilities to simulate diurnal and seasonal variation of leaf-level and canopy-scale photosynthesis in temperate and boreal forests. However, long-term prediction of future forest productivity in a changing climate may be more dependent on how climate and biological anomalies influence extremes in interannual to decadal variability of canopy ecosystem carbon exchanges. These exchanges can differ markedly from leaf level responses, especially owing to the prevalence of long lags in nutrient and water cycling. Until recently, multiple long-term (10+ year) high temporal frequency (daily) observations of canopy exchange were not available to reliably assess this claim. An analysis of one of the longest running North American eddy covariance flux towers reveals that single climate variables do not adequately explain carbon exchange anomalies beyond the seasonal timescale. Daily to weekly lagged anomalies of photosynthesis positively autocorrelate with daily photosynthesis. This effect suggests a negative feedback in photosynthetic response to climate extremes, such as anomalies in evapotranspiration and maximum temperature. Moisture stress in the prior season did inhibit photosynthesis, but mechanisms are difficult to assess. A complex interplay of integrated and lagged productivity and moisture-limiting factors indicate a critical role of seasonal thresholds that limit growing season length and peak productivity. These results lead toward a new conceptual framework for improving earth system models with long-term flux tower observations.

  2. Robust inferences on climate change patterns of precipitation extremes in the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    de Melo-Gonçalves, Paulo; Rocha, Alfredo; Santos, João A.

    2016-08-01

    grid points where a significant climate change is found with a predefined low uncertainty. Results highlight the importance of taking into account the spread across an ensemble of climate simulations when making inferences on climate change from the ensemble-mean or ensemble-median. This is specially true for climate projections of extreme indices such CDD and R95T. For PRCTOT, a decrease in annual precipitation over the entire peninsula is projected, specially in the north and northwest where it can decrease down to 400 mm by the middle of the 21st century. This decrease is expected to occur throughout the year except in winter. Annual CDD is projected to increase till the middle of the 21st century overall the peninsula, reaching more than three weeks in the southwest. This increase is projected to occur in summer and spring. For Rx5day, a decrease is projected to occur during spring and autumn in the major part of the peninsula, and during summer in northern Iberia. Finally, R95T is projected to decrease around 20% in northern Iberia in summer, and around 15% in the south-southwest in autumn.

  3. Impact of parameter uncertainty on extreme flow simulation in SWAT model under climate change

    NASA Astrophysics Data System (ADS)

    Zhang, Xujie; Xu, Yue-Ping; Ma, Chong; Gao, Xichao

    2013-04-01

    Climate change affects hydrology and water resources significantly, including extreme flows. There are, however, large uncertainties in hydrological analysis. In this paper, the SWAT (Soil and Water Assessment Tool) model was used to evaluate the impact of climate change on extreme flows in Lanjiang catchment, one sub-basin of Qiantang River Basin, East China. This hydrological model was set up and calibrated carefully. The original parameters were replaced by aggregate parameters to reduce the computation effort. The SUFI-2 (Sequential Uncertainty Fitting Ver. 2) method was employed to estimate model parameters and analyze the uncertainties. Three future emission scenarios A1B, A2 and B2 were chosen to investigate the uncertainty in climate change projections, and a regional climate model PRECIS (Providing REgional Climates for Impacts Studies) was applied to downscale the General Circulation Model (GCM) outputs. The downscaled precipitation and temperature were put into SWAT model to simulate future flows in the period 2011-2040. Finally, extreme flows and their uncertainties were analyzed using the Generalized Pareto (GPA) distribution, and the results were compared with those using Pearson type III (PE3) and Generalized Extreme-value (GEV) distributions. The SWAT model calibration and validation results indicate that SWAT model has a good performance in Lanjiang catchment. The simulated annual discharge of Lanxi station shows an increasing trend in the baseline period (1961-1990), while a decreasing trend under both A2 and B2 scenarios, which means there may be less water resources available in this area in the period 2011-2040. The simulated future extreme flows show that, according to the GPA distribution, the design discharges in small return periods under A1B, A2 and B2 scenarios are possibly larger than those in the baseline period, while the design discharges in large return periods will be possibly smaller than that in the baseline period. The design

  4. Modeling climate change induced hydrological extremes in the Kafue River Basin in Southern Africa

    NASA Astrophysics Data System (ADS)

    Ngongondo, C.; Li, L.; Gong, L.; Xu, C.-Y.

    2012-04-01

    Climate change impact projections in southern Africa suggest significant declines in flows in the major river basins. However, impacts of climate change on hydrological extremes (floods) in the region remain a grey area despite the threat they pose to human life and property. In this study, the impacts of climate change on extreme flows in the upper Kafue River basin, a major tributary of the Zambezi River, were investigated. Catchment hydrography was determined using the Hydro1k at a spatial resolution of 1 km resulting in an approximate registered area of 23,000 km2. The daily global WASMOD-M model was calibrated and validated during 1971 to 2001 with the WATCH Forcing Data (WFD) against observed discharge at Machiya gauging station from the Gridded River Discharge Data Centre(GRDC). Future climate change scenarios for extreme flows were derived by forcing the model with outputs from three GCM's (ECHAM, CMCC3 and IPSL) under the IPCC's SRES A2 and B1 scenarios from 2020 to 2100 at daily timescale. During calibration and validation, the NS coefficient value was above 0.80 and the Pearson correlation coefficient between observed and simulated flows of 0.9, suggesting acceptable model performance. Current and future extremes for each scenario were analyzed using the Peak Over Threshold (POT) analysis fitted to the Generalised Pareto Distribution (GPA), which provided less RMSE values as compared to Annual Maximum Series (AMS) fitted to the Generalized Extreme Value (GEV) distribution. The results show considerable departures from the reference period extremes for most of GCM scenarios considered, with both the A2 and B1 scenarios of the IPSL resulting in higher projected flows as compared to the other two models. On average, floods with return periods T=5,10,50,100,1000 years increased from Q (m3 s-1) = 626.6, 673.9, 767.1, 802.3, 903.7 during the reference period to Q (m3s-1) = 793.5, 873.4, 1046.2, 1119.2, 1364.8 respectively. The approach in our study has a

  5. Climate Change Altered Disturbance Regimes in High Elevation Pine Ecosystems

    NASA Astrophysics Data System (ADS)

    Logan, J. A.

    2004-12-01

    Insects in aggregate are the greatest cause of forest disturbance. Outbreaks of both native and exotic insects can be spectacular events in both their intensity and spatial extent. In the case of native species, forest ecosystems have co-evolved (or at least co-adapted) in ways that incorporate these disturbances into the normal cycle of forest maturation and renewal. The time frame of response to changing climate, however, is much shorter for insects (typically one year) than for their host forests (decades or longer). As a result, outbreaks of forest insects, particularly bark beetles, are occurring at unprecedented levels throughout western North America, resulting in the loss of biodiversity and potentially entire ecosystems. In this talk, I will describe one such ecosystem, the whitebark pine association at high elevations in the north-central Rocky Mountains of the United States. White bark pines are keystone species, which in consort with Clark's nutcracker, build entire ecosystems at high elevations. These ecosystems provide valuable ecological services, including the distribution and abundance of water resources. I will briefly describe the keystone nature of whitebark pine and the historic role of mountain pine beetle disturbance in these ecosystems. The mountain pine beetle is the most important outbreak insect in forests of the western United States. Although capable of spectacular outbreak events, in historic climate regimes, outbreak populations were largely restricted to lower elevation pines; for example, lodgepole and ponderosa pines. The recent series of unusually warm years, however, has allowed this insect to expand its range into high elevation, whitebark pine ecosystems with devastating consequences. The aspects of mountain pine beetle thermal ecology that has allowed it to capitalize so effectively on a warming climate will be discussed. A model that incorporates critical thermal attributes of the mountain pine beetle's life cycle was

  6. Tackling air pollution and extreme climate changes in China: Implementing the Paris climate change agreement.

    PubMed

    Tambo, Ernest; Duo-Quan, Wang; Zhou, Xiao-Nong

    2016-10-01

    China still depends on coal for more than 60% of its power despite big investments in the process of shifting to nuclear, solar and wind power renewable energy resources alignment with Paris climate change agreement (Paris CCA). Chinese government through the Communist Party Central Committee (CPCC) ascribes great importance and commitment to Paris CCA legacy and history landmark implementation at all levels. As the world's biggest carbon dioxide emitter, China has embarked on "SMART" pollution and climate changes programs and measures to reduce coal-fired power plants to less than 50% in the next five years include: new China model of energy policies commitment on CO2 and greenhouse gas emissions reductions to less than 20% non-fossil energy use by 2030 without undermining their economic growth, newly introduced electric vehicles transportation benefits, interactive and sustained air quality index (AQI) monitoring systems, decreasing reliance on fossil fuel economic activities, revision of energy price reforms and renewable energy to less energy efficient technologies development. Furthermore, ongoing CPCC improved environmental initiatives, implemented strict regulations and penalties on local companies and firms' pollution production management, massive infrastructures such as highways to reduce CO2 expansion of seven regional emissions trading markets and programs for CO2 emissions and other pollutants are being documented. Maximizing on the centralized nature of the China's government, implemented Chinese pollution, climate changes mitigation and adaptation initiatives, "SMART" strategies and credible measures are promising. A good and practical example is the interactive and dynamic website and database covering 367 Chinese cities and providing real time information on environmental and pollution emissions AQI. Also, water quality index (WQI), radiation and nuclear safety monitoring and management systems over time and space. These are ongoing Chinese

  7. Tackling air pollution and extreme climate changes in China: Implementing the Paris climate change agreement.

    PubMed

    Tambo, Ernest; Duo-Quan, Wang; Zhou, Xiao-Nong

    2016-10-01

    China still depends on coal for more than 60% of its power despite big investments in the process of shifting to nuclear, solar and wind power renewable energy resources alignment with Paris climate change agreement (Paris CCA). Chinese government through the Communist Party Central Committee (CPCC) ascribes great importance and commitment to Paris CCA legacy and history landmark implementation at all levels. As the world's biggest carbon dioxide emitter, China has embarked on "SMART" pollution and climate changes programs and measures to reduce coal-fired power plants to less than 50% in the next five years include: new China model of energy policies commitment on CO2 and greenhouse gas emissions reductions to less than 20% non-fossil energy use by 2030 without undermining their economic growth, newly introduced electric vehicles transportation benefits, interactive and sustained air quality index (AQI) monitoring systems, decreasing reliance on fossil fuel economic activities, revision of energy price reforms and renewable energy to less energy efficient technologies development. Furthermore, ongoing CPCC improved environmental initiatives, implemented strict regulations and penalties on local companies and firms' pollution production management, massive infrastructures such as highways to reduce CO2 expansion of seven regional emissions trading markets and programs for CO2 emissions and other pollutants are being documented. Maximizing on the centralized nature of the China's government, implemented Chinese pollution, climate changes mitigation and adaptation initiatives, "SMART" strategies and credible measures are promising. A good and practical example is the interactive and dynamic website and database covering 367 Chinese cities and providing real time information on environmental and pollution emissions AQI. Also, water quality index (WQI), radiation and nuclear safety monitoring and management systems over time and space. These are ongoing Chinese

  8. Temporal Fluctuations in Weather and Climate Extremes That Cause Economic and Human Health Impacts: A Review.

    NASA Astrophysics Data System (ADS)

    Kunkel, Kenneth E.; Pielke, Roger A., Jr.; Changnon, Stanley A.

    1999-06-01

    This paper reviews recent work on trends during this century in societal impacts (direct economic losses and fatalities) in the United States from extreme weather conditions and compares those with trends of associated atmospheric phenomena. Most measures of the economic impacts of weather and climate extremes over the past several decades reveal increasing losses. But trends in most related weather and climate extremes do not show comparable increases with time. This suggests that increasing losses are primarily due to increasing vulnerability arising from a variety of societal changes, including a growing population in higher risk coastal areas and large cities, more property subject to damage, and lifestyle and demographic changes subjecting lives and property to greater exposure.Flood damages and fatalities have generally increased in the last 25 years. While some have speculated that this may be due in part to a corresponding increase in the frequency of heavy rain events, the climate contribution to the observed impacts trends remains to be quantified. There has been a steady increase in hurricane losses. However, when changes in population, inflation, and wealth are considered, there is instead a downward trend. This is consistent with observations of trends in hurricane frequency and intensity. Increasing property losses due to thunderstorm-related phenomena (winds, hail, tornadoes) are explained entirely by changes in societal factors, consistent with the observed trends in the thunderstorm phenomena. Winter storm damages have increased in the last 10-15 years and this appears to be partially due to increases in the frequency of intense nor'easters. There is no evidence of changes in drought-related losses (although data are poor) and no apparent trend in climatic drought frequency. There is also no evidence of changes in the frequency of intense heat or cold waves.

  9. Connecting differential responses of native and invasive riparian plants to climate change and environmental alteration.

    PubMed

    Flanagan, Neal E; Richardson, Curtis J; Ho, Mengchi

    2015-04-01

    Climate change is predicted to impact river systems in the southeastern United States through alterations of temperature, patterns of precipitation and hydrology. Future climate scenarios for the southeastern United States predict (1) surface water temperatures will warm in concert with air temperature, (2) storm flows will increase and base flows will decrease, and (3) the annual pattern of synchronization between hydroperiod and water temperature will be altered. These alterations are expected to disturb floodplain plant communities, making them more vulnerable to establishment of invasive species. The primary objective of this study is to evaluate whether native and invasive riparian plant assemblages respond differently to alterations of climate and land use. To study the response of riparian wetlands to watershed and climate alterations, we utilized an existing natural experiment imbedded in gradients of temperature and hydrology-found among dammed and undammed rivers. We evaluated a suite of environmental variables related to water temperature, hydrology, watershed disturbance, and edaphic conditions to identify the strongest predictors of native and invasive species abundances. We found that native species abundance is strongly influenced by climate-driven variables such as temperature and hydrology, while invasive species abundance is more strongly influenced by site-specific factors such as land use and soil nutrient availability. The patterns of synchronization between plant phenology, annual hydrographs, and annual water temperature cycles may be key factors sustaining the viability of native riparian plant communities. Our results demonstrate the need to understand the interactions between climate, land use, and nutrient management in maintaining the species diversity of riparian plant communities. Future climate change is likely to result in diminished competitiveness of native plant species, while the competitiveness of invasive species will increase

  10. Connecting differential responses of native and invasive riparian plants to climate change and environmental alteration.

    PubMed

    Flanagan, Neal E; Richardson, Curtis J; Ho, Mengchi

    2015-04-01

    Climate change is predicted to impact river systems in the southeastern United States through alterations of temperature, patterns of precipitation and hydrology. Future climate scenarios for the southeastern United States predict (1) surface water temperatures will warm in concert with air temperature, (2) storm flows will increase and base flows will decrease, and (3) the annual pattern of synchronization between hydroperiod and water temperature will be altered. These alterations are expected to disturb floodplain plant communities, making them more vulnerable to establishment of invasive species. The primary objective of this study is to evaluate whether native and invasive riparian plant assemblages respond differently to alterations of climate and land use. To study the response of riparian wetlands to watershed and climate alterations, we utilized an existing natural experiment imbedded in gradients of temperature and hydrology-found among dammed and undammed rivers. We evaluated a suite of environmental variables related to water temperature, hydrology, watershed disturbance, and edaphic conditions to identify the strongest predictors of native and invasive species abundances. We found that native species abundance is strongly influenced by climate-driven variables such as temperature and hydrology, while invasive species abundance is more strongly influenced by site-specific factors such as land use and soil nutrient availability. The patterns of synchronization between plant phenology, annual hydrographs, and annual water temperature cycles may be key factors sustaining the viability of native riparian plant communities. Our results demonstrate the need to understand the interactions between climate, land use, and nutrient management in maintaining the species diversity of riparian plant communities. Future climate change is likely to result in diminished competitiveness of native plant species, while the competitiveness of invasive species will increase

  11. Feedbacks between climate change, surface processes, and extreme convective precipitation events (Invited)

    NASA Astrophysics Data System (ADS)

    Galewsky, J.

    2009-12-01

    In a classic 1951 paper, Luna Leopold showed that the ratio of rainfall extrema to rainfall averages increases as the climate becomes more arid. This line of thinking has influenced much geomorphology research, but the basic meteorological mechanisms involved remain unknown. The potential for drought to increase both precipitation intensity and slope erodibility, which further decreases soil and vegetation cover, suggests the potential for previously unrecognized feedbacks between climate and landscape dynamics in semi-arid regions. The modeling framework used here is similar to that used for studies of oceanic radiative-convective equilibrium but uses surface sensible and latent heat fluxes derived from GCM projections of future climate change for the American Southwest. The model is run for 30 days until an equilibrium is established between radiative cooling and convective heating in the atmosphere. Prelimary analysis based on extreme value theory shows potentially important changes in the characteristics of convection over semi-arid landscapes as a result of projected anthropogenic climate change. The concept of an equilibrium convective ensemble, and its sensitivity to changing surface processes, may thus be a useful complement to geomorphic studies of landscape-climate interactions.

  12. Late Cretaceous Climate, Vegetation and Ocean Interactions: AN Earth System Approach to Modeling AN Extreme Climate

    NASA Astrophysics Data System (ADS)

    Deconto, Robert Michael

    The Campanian age of the Late Cretaceous was warm, with no evidence for permanent or seasonal sea ice at high latitudes. Sea level was high, creating extensive epicontinental and shallow shelf seas. Very low meridional thermal gradients existed in the oceans and on land. Campanian (80 Ma) climate and vegetation have been simulated using GENESIS (Global ENvironmental and Ecological Simulation of Interactive Systems) Version 2.0 and EVE (Equilibrium Vegetation Ecology model), developed by the Climate Change Research section of the Climate and Global Dynamics division at NCAR (National Center for Atmospheric Research). GENESIS is a comprehensive Earth system model, requiring high resolution (2^circ by 2^circ) solid earth boundary condition data as input for paleoclimate simulations. Boundary condition data define certain prescribed global fields such as the distribution of land-sea-ice, topography, orographic roughness, and soil texture, as well as atmospheric chemistry, the solar constant, and orbital parameters that define the latitudinal distribution of solar insolation. A comprehensive, high resolution paleogeography has been reconstructed for the Campanian. The paleogeography, based on a new global plate tectonic model, provides the framework for the solid earth boundary conditions used in the paleoclimate simulation. Because terrestrial ecosystems influence global climate by affecting the exchange of energy, water and momentum between the land surface and the atmosphere, the distribution of global vegetation should be included in pre-Quaternary paleoclimate simulations. However, reconstructing global vegetation distributions from the fossil record is difficult. EVE predicts the equilibrium state of plant community structure as a function of climate and fundamental ecological principles. The model has been modified to reproduce a vegetation distribution based on life forms that existed in the Late Cretaceous. EVE has been applied as a fully interactive component

  13. Climate change alters ecological strategies of soil bacteria.

    PubMed

    Evans, Sarah E; Wallenstein, Matthew D

    2014-02-01

    The timing and magnitude of rainfall events are expected to change in future decades, resulting in longer drought periods and larger rainfall events. Although microbial community composition and function are both sensitive to changes in rainfall, it is unclear whether this is because taxa adopt strategies that maximise fitness under new regimes. We assessed whether bacteria exhibited phylogenetically conserved ecological strategies in response to drying-rewetting, and whether these strategies were altered by historical exposure to experimentally intensified rainfall patterns. By clustering relative abundance patterns, we identified three discrete ecological strategies and found that tolerance to drying-rewetting increased with exposure to intensified rainfall patterns. Changes in strategy were primarily due to changes in community composition, but also to strategy shifts within taxa. These moisture regime-selected ecological strategies may be predictable from disturbance history, and are likely to be linked to traits that influence the functional potential of microbial communities.

  14. Simulation of Extreme Surface Winds by Regional Climate Models in the NARCCAP Archive

    NASA Astrophysics Data System (ADS)

    Hatteberg, R.; Takle, E. S.

    2011-12-01

    Surface winds play a significant role in many natural processes as well as providing a very important ecological service for many human activities. Surface winds ventilate pollutants and heat from our cities, contribute to pollination for our crops, and regulate the fluxes of heat, moisture, and carbon dioxide from the earth's surface. Many environmental models such as biogeochemical models, crop models, lake models, pollutant transport models, etc., use surface winds as a key variable. Studies of the impacts of climate change and climate variability on a wide range of natural systems and coupled human-natural systems frequently need information on how surface wind speeds will change as greenhouse gas concentrations in the earth's atmosphere change. We have studied the characteristics of extreme winds - both high winds and low winds - created by regional climate models (RCMs) in the NARCCAP archives. We evaluated the capabilities of five RCMs forced by NCEP reanalysis data as well as global climate model (GCM) data for contemporary and future scenario climates to capture the observed statistical distribution of surface winds, both high-wind events and low-wind conditions. Our domain is limited to the Midwest (37°N to 49°N, -82°W to -101°W) with the Great Lakes masked out, which eliminates orographic effects that may contribute to regional circulations. The majority of this study focuses on the warm seasonal in order to examine derechos on the extreme high end and air pollution and plant processes on the low wind speed end. To examine extreme high winds we focus on derechos, which are long-lasting convectively driven extreme wind events that frequently leave a swath of damage extending across multiple states. These events are unusual in that, despite their relatively small spatial scale, they can persist for hours or even days, drawing energy from well-organized larger mesoscale or synoptic scale processes. We examine the ability of NARCCAP RCMs to reproduce

  15. Analysis of Extreme Heat in Historical and Projected Climate Simulations for Regional Climate Planning Purposes in the U.S.

    NASA Astrophysics Data System (ADS)

    Geil, K.; Zeng, X.; McMahan, B.; Ferguson, D. B.

    2015-12-01

    The U.S. National Climate Assessment (NCA) states that global climate models predict more extreme temperatures and more frequent, intense, and longer heat waves on a regional basis as global temperatures rise throughout the 21st century, but a thorough test of whether these models can simulate observed heat metrics and trends over the historical period was not included in the assessment. Understanding the capabilities of climate models over the historical period is crucial to assessing our confidence in their predictive ability at regional scales. Our work fills this research gap by evaluating the performance of Coupled Model Intercomparison Phase 5 (CMIP5) models as compared to observational data using multiple heat metrics. Our metrics are targeted for the southwest United States, but our regional analysis covers the entire continental U.S. and Alaska using 7 of the regions delineated by the NCA. The heat metrics include heat wave and cold wave frequency, intensity, and duration, overnight low temperatures, onset and length of the hot season, and human heat stress. For the best performing models, we compute the same heat metrics for the RCP scenarios. In addition to presenting the results of our CMIP5 historical and RCP analyses, we also describe how our results may be applied to the benefit of our community in Southern Arizona as a case study. Our research will be used by NOAA's Climate Assessment for the Southwest (CLIMAS) and by an interdisciplinary collaborative team of researchers from the University of Arizona working with an electric utility to integrate climate information into their strategic planning.

  16. Potential future increase in extreme one-hour precipitation events over Europe due to climate change.

    PubMed

    Larsen, A N; Gregersen, I B; Christensen, O B; Linde, J J; Mikkelsen, P S

    2009-01-01

    In this study the potential increase of extreme precipitation in a future warmer European climate has been examined. Output from the regional climate model (RCM) HIRHAM4 covering Europe has been analysed for two periods, a control period 1961-1990 and a scenario 2071-2100, the latter following the IPCC scenario A2. The model has a resolution of about 12 km, which is unique compared with existing RCM studies that typically operate at 25-50 km scale, and make the results relevant to hydrological phenomena occurring at the spatial scale of the infrastructure designed to drain off rainfall in large urban areas. Extreme events with one- and 24-hour duration were extracted using the Partial Duration Series approach, a Generalized Pareto Distribution was fitted to the data and T-year events for return periods from 2 to 100 years were calculated for the control and scenario period in model cells across Europe. The analysis shows that there will be an increase of the intensity of extreme events generally in Europe; Scandinavia will experience the highest increase and southern Europe the lowest. A 20 year 1-hour precipitation event will for example become a 4 year event in Sweden and a 10 year event in Spain. Intensities for short durations and high return periods will increase the most, which implies that European urban drainage systems will be challenged in the future.

  17. Climate change and probabilistic scenario of streamflow extremes in a cryospheric alpine region

    NASA Astrophysics Data System (ADS)

    Yang, Tao; Gao, Cheng

    2015-04-01

    Future projections of streamflow extremes are of paramount significance in assessing the climate impacts on social and natural systems, particularly for the Himalayan alpine region in the Tibetan Plateau known as the Asian Water Tower. This study strives to quantify the uncertainties from different sources in simulating future extreme flows and seeks to construct reliable scenarios of future extreme flows for the headwater catchment of the Yellow River Basin in the 21st century. The results can be formulated as follows: (1) The revised snow model based on a daily active temperature method is superior to the commonly used degree-day method in simulating snowmelt processes. (2) In general, hydrological models contribute more uncertainties than the downscaling methods in high flow and low flow over the cryospheric alpine regions characterized by the snow-rainfall induced runoff processes under most scenarios. Meanwhile, impacts to uncertainty vary with time. (3) The ultimate probability of high-flow exhibits a downward trend in future by using an unconditional method, whereas positive changes in probability of low-flow are projected. The method in the work includes a variety of influence from different contributing factors (e.g. downscaling models, hydrological models, model parameters, and their simulation skills) on streamflow projection, therefore can offer more information (i.e. different percentiles of flow and uncertainty ranges) for future water resources planning compared with the purely deterministic approaches. Hence, the results are beneficial to boost our current methodologies of climate impact research in the Himalayan alpine zone.

  18. Climate change and probabilistic scenario of streamflow extremes in an alpine region

    NASA Astrophysics Data System (ADS)

    Yang, Tao; Wang, Xiaoyan; Yu, Zhongbo; Krysanova, Valentina; Chen, Xi; Schwartz, Franklin W.; Sudicky, Edward A.

    2014-07-01

    Future projections of streamflow extremes are of paramount significance in assessing the climate impacts on social and natural systems, particularly for the Himalayan alpine region in the Tibetan Plateau known as the Asian water tower. This study strives to quantify the uncertainties from different sources in simulating future extreme flows and seeks to construct reliable scenarios of future extreme flows for the headwater catchment of the Yellow River Basin in the 21st century. The results can be formulated as follows: (1) The revised snow model based on a daily active temperature method is superior to the commonly used degree-day method in simulating snowmelt processes. (2) In general, hydrological models contribute more uncertainties than the downscaling methods in high flow and low flow over the cryospheric alpine regions characterized by the snow-rainfall-induced runoff processes under most scenarios. Meanwhile, impacts to uncertainty vary with time. (3) The ultimate probability of high flow exhibits a downward trend in future by using an unconditional method, whereas positive changes in the probability of low flow are projected. The method in the work includes a variety of influence from different contributing factors (e.g., downscaling models, hydrological models, model parameters, and their simulation skills) on streamflow projection, therefore can offer more information (i.e., different percentiles of flow and uncertainty ranges) for future water resource planning compared with the purely deterministic approaches. Hence, the results are beneficial to boost our current methodologies of climate impact research in the Himalayan alpine zone.

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

    NASA Astrophysics Data System (ADS)

    Schulz, Karsten; Bernhardt, Matthias

    2016-04-01

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

  20. Release of Mercury Mine Tailings from Mine Impacted Watersheds by Extreme Events Resulting from Climate Change

    NASA Astrophysics Data System (ADS)

    Rytuba, J. J.

    2015-12-01

    An increase in intensity and frequency of extreme events resulting from climate change is expected to result in extreme precipitation events on both regional and local scales. Extreme precipitation events have the potential to mobilize large volumes of mercury (Hg) mine tailings in watersheds where tailings reside in the floodplain downstream from historic Hg mines. The California Hg mineral belt produced one third of the worlds Hg from over 100 mines from the 1850's to 1972. In the absence of environmental regulations, tailings were disposed of into streams adjacent to the mines in order to have them transported from the mine site during storm events. Thus most of the tailings no longer reside at the mine site. Addition of tailings to the streams resulted in stream aggradation, increased over-bank flow, and deposition of tailings in the floodplain for up to 25 kms downstream from the mines. After cessation of mining, the decrease in tailings entering the streams resulted in degradation, incision of the streams into the floodplain, and inability of the streams to access the floodplain. Thus Hg tailings have remained stored in the floodplain since cessation of mining. Hg phases in these tailings consist of cinnabar, metacinnabar and montroydite based on EXAFS analysis. Size analysis indicates that Hg phases are fine grained, less than 1 um. The last regional scale extreme precipitation events to effect the entire area of the California Hg mineral belt were the ARkStorm events of 1861-1862 that occurred prior to large scale Hg mining. Extreme regional ARkStorm precipitation events as well as local summer storms, such as the July 2006 flood in the Clear Creek Hg mining district, are expected to increase in frequency and have the potential to remobilize the large volume of tailings stored in floodplain deposits. Although Hg mine remediation has decreased Hg release from mine sites in a period of benign climate, no remediation efforts have addressed the large source of

  1. Attributing regional effects of the 2014 Jordanian extreme drought to external climate drivers

    NASA Astrophysics Data System (ADS)

    Bergaoui, Karim; Mitchell, Dann; Zaaboul, Rashyd; Otto, Friederike; McDonnell, Rachael; Dadson, Simon; Allen, Myles

    2015-04-01

    Throughout 2014, the regions of Jordan, Israel, Lebanon and Syria have experienced a persistent draught with clear impacts on the local populations. In this study we perform an extreme event attribution analysis of how such a draught has changed under climate change, with a specific focus on the flow rate of the Upper Jordan river and the water level of Lake Tiberious (AKA the Sea of Galilee). Both of which hold major societal, political and religious importance. To perform the analysis we make use of distributed computing power to run thousands of modelled years of 2014 with slightly different initial conditions. We use an atmosphere only model (HadAM3p) with a nested 50 km regional model covering Africa and the Middle East. The 50 km model atmospheric variables will be used directly to force offline our 1 km LIS surface model. Two separate experiments and simulations are performed, 1. for all known climate forcings that are present in 2014, and 2. for a naturalised 2014 scenario where we assume humans never impacted the climate. We perform sensitivity analyses on the observed precipitation over the regions of interest, and determine that the TRMM data is in good agreement with station data obtained from the Jordanian Ministry of Water. Using a combination of the TRMM and model data we are able to make clear statements on the attribution of a 2014-like extreme draught event to human causal factors.

  2. Preface: Monitoring and modelling to guide coastal adaptation to extreme storm events in a changing climate

    NASA Astrophysics Data System (ADS)

    Brown, J. M.; Ciavola, P.; Masselink, G.; McCall, R.; Plater, A. J.

    2016-02-01

    Storms across the globe and their associated consequences in coastal zones (flooding and erosion), combined with the long-term geomorphic evolution of our coastlines, are a threat to life and assets, both socioeconomic and environmental. In a changing climate, with a rising global sea level, potentially changing patterns in storm tracks and storminess, and rising population density and pressures on the coastal zone, the future risk of coastal storm impacts is likely to increase. Coastal managers and policy makers therefore need to make effective and timely decisions on the use of resources for the immediate and longer Research focused on "monitoring and modelling to guide coastal adaptation to extreme storm events in a changing climate" is becoming more common; its goal is to provide science-based decision support for effective adaptation to the consequences of storm impacts, both now and under future climate scenarios at the coast. The growing transfer of information between the science community and end-users is enabling leading research to have a greater impact on the socioeconomic resilience of coastal communities. This special issue covers recent research activities relating to coastal hazard mapping in response to extreme events, economic impacts of long-term change, coastal processes influencing management decisions and the development of online decision support tools.

  3. Assessment of extreme precipitation events over Amazon simulated by global climate models from HIGEM family

    NASA Astrophysics Data System (ADS)

    Custodio, M. D. S.; Ambrizzi, T.; Da Rocha, R.

    2015-12-01

    The increased horizontal resolution of climate models aims to improve the simulations accuracy and to understand the non-linear processes during interactions between different spatial scales within the climate system. Up to this moment, these interactions did not have a good representation on low horizontal resolution GCMs. The variations of extreme climatic events had been described and analyzed in the scientific literature. In a scenario of global warming it is necessary understanding and explaining extreme events and to know if global models may represent these events. The purpose of this study was to understand the impact of the horizontal resolution in high resolution coupled and atmospheric global models of HiGEM project in simulating atmospheric patterns and processes of interaction between spatial scales. Moreover, evaluate the performance of coupled and uncoupled versions of the High-Resolution Global Environmental Model in capturing the signal of interannual and intraseasonal variability of precipitation over Amazon region. The results indicated that the grid refinement and ocean-atmosphere coupling contributes to a better representation of seasonal patterns, both precipitation and temperature, on the Amazon region. Besides, the climatic models analyzed represent better than other models (regional and global) the climatic characteristics of this region. This indicates a breakthrough in the development of high resolution climate models. Both coupled and uncoupled models capture the observed signal of the ENSO and MJO oscillations, although with reversed phase in some cases. The interannual variability analysis showed that coupled simulations intensify the impact of the ENSO in the Amazon. In the intraseasonal scale, although the simulations intensify this signal, the coupled models present larger similarities with observations than the atmospheric models for the extremes of precipitation. The simulation of ENSO in GCMs can be attributed to their high

  4. Air pollution may alter efforts to mitigate climate change

    NASA Astrophysics Data System (ADS)

    Yassaa, Noureddine

    2016-02-01

    Renewable energy, considered in the past as a mitigation option to climate change by reducing carbon emission, is now becoming a source of energy security and competing fossil fuels in many areas of the world. According to recent reports (e.g., IEA, IRENA, REN21), renewable energy has reached in 2014 a historical record of power generation capacity. With 1712 GW installed capacity in 2014, renewable energy represents 27.7% of the world's power generating capacity. Solar photovoltaic (PV) energy, conversion of solar light to electricity through solar panels, has increased to reach 177 GW mostly due to the political engagement for the deployment of renewable through targeted programs and the decrease of PV panels prize in the market (roughly 80% decrease since 2008 according to IRENA's report). Concentrated Solar Power (CSP), reaching a total capacity of 4.4 GW in 2014 (REN21 Report), is also demonstrating a clear growth and progresses have been made with regards to the efficiency, the storage capacity and the cost. In order to reduce the energy consumption and carbon emissions, water solar heaters are being installed in the rooftop of households and a total capacity of 406 GW thermal was recorded in 2014 (REN21 Report).

  5. Recent advances on reconstruction of climate and extreme events in China for the past 2000 year

    NASA Astrophysics Data System (ADS)

    Zheng, Jingyun; Hao, Zhixin; Ge, Quansheng; Liu, Yang

    2016-04-01

    The study of regional climate changes for past 2000 year could present spatial pattern of climate variation and various historical analogues for the sensitivity and operation of the climate system (e.g., the modulations of internal variability, feedbacks and teleconnections, abrupt changes and regional extreme events, etc.) from inter-annual to centennial scales and provide the knowledge to predict and project climate in the near future. China is distinguished by a prominent monsoon climate in east, continental arid climate in northwest and high land cold climate in Qinghai-Tibetan Plateau located at southwest. The long history of civilization and the variety of climate in China provides an abundant and well-dated documentary records and a wide range of natural archives (e.g., tree-ring, ice core, stalagmite, varved lake sediment, etc.) for high-resolution paleoclimate reconstruction. This paper presented a review of recent advances on reconstruction of climate and extreme events in China for the past 2000 years. In recent 10 years, there were many new high-resolution paleoclimatic reconstructions reported in China, e.g., the annual and decadal resolution series of temperature and precipitation in eastern China derived from historical documents, in western China derived from tree-ring and other natural archives. These new reconstructions provided more proxies and better spatial coverage to understand the characteristics of climate change over China and the uncertainty of regional reconstructions, as well as to reconstruct the high-resolution temperature series and the spatial pattern of precipitation change for whole China in the past millenniums by synthesizing the multi-proxy together. The updated results show that, in China, the warm intervals for the past 2000 years were in AD 1-200, AD 551-760, AD 951-1320, and after AD 1921; as well as the cold intervals were in AD 201-350, AD 441-530, AD 781-950, and AD 1321-1920. The extreme cold winters occurred in periods

  6. Will Global Climate Change Alter Fundamental Human Immune Reactivity: Implications for Child Health?

    PubMed

    Swaminathan, Ashwin; Lucas, Robyn M; Harley, David; McMichael, Anthony J

    2014-11-11

    The human immune system is an interface across which many climate change sensitive exposures can affect health outcomes. Gaining an understanding of the range of potential effects that climate change could have on immune function will be of considerable importance, particularly for child health, but has, as yet, received minimal research attention. We postulate several mechanisms whereby climate change sensitive exposures and conditions will subtly impair aspects of the human immune response, thereby altering the distribution of vulnerability within populations-particularly for children-to infection and disease. Key climate change-sensitive pathways include under-nutrition, psychological stress and exposure to ambient ultraviolet radiation, with effects on susceptibility to infection, allergy and autoimmune diseases. Other climate change sensitive exposures may also be important and interact, either additively or synergistically, to alter health risks. Conducting directed research in this area is imperative as the potential public health implications of climate change-induced weakening of the immune system at both individual and population levels are profound. This is particularly relevant for the already vulnerable children of the developing world, who will bear a disproportionate burden of future adverse environmental and geopolitical consequences of climate change.

  7. Will Global Climate Change Alter Fundamental Human Immune Reactivity: Implications for Child Health?

    PubMed Central

    Swaminathan, Ashwin; Lucas, Robyn M.; Harley, David; McMichael, Anthony J.

    2014-01-01

    The human immune system is an interface across which many climate change sensitive exposures can affect health outcomes. Gaining an understanding of the range of potential effects that climate change could have on immune function will be of considerable importance, particularly for child health, but has, as yet, received minimal research attention. We postulate several mechanisms whereby climate change sensitive exposures and conditions will subtly impair aspects of the human immune response, thereby altering the distribution of vulnerability within populations—particularly for children—to infection and disease. Key climate change-sensitive pathways include under-nutrition, psychological stress and exposure to ambient ultraviolet radiation, with effects on susceptibility to infection, allergy and autoimmune diseases. Other climate change sensitive exposures may also be important and interact, either additively or synergistically, to alter health risks. Conducting directed research in this area is imperative as the potential public health implications of climate change-induced weakening of the immune system at both individual and population levels are profound. This is particularly relevant for the already vulnerable children of the developing world, who will bear a disproportionate burden of future adverse environmental and geopolitical consequences of climate change. PMID:27417487

  8. Aerosol effect on climate extremes in Europe under different future scenarios

    NASA Astrophysics Data System (ADS)

    Sillmann, J.; Pozzoli, L.; Vignati, E.; Kloster, S.; Feichter, J.

    2013-05-01

    This study investigates changes in extreme temperature and precipitation events under different future scenarios of anthropogenic aerosol emissions (i.e., SO2 and black and organic carbon) simulated with an aerosol-climate model (ECHAM5-HAM) with focus on Europe. The simulations include a maximum feasible aerosol reduction (MFR) scenario and a current legislation emission (CLEmod) scenario where Europe implements the MFR scenario, but the rest of the world follows the current legislation scenario and a greenhouse gas scenario. The strongest changes relative to the year 2000 are projected for the MFR scenario, in which the global aerosol reduction greatly enforces the general warming effect due to greenhouse gases and results in significant increases of temperature and precipitation extremes in Europe. Regional warming effects can also be identified from aerosol reductions under the CLEmodscenario. This becomes most obvious in the increase of the hottest summer daytime temperatures in Northern Europe.

  9. Geomorphological records of extreme floods and their relationship to decadal-scale climate change

    NASA Astrophysics Data System (ADS)

    Foulds, S. A.; Griffiths, H. M.; Macklin, M. G.; Brewer, P. A.

    2014-07-01

    Extreme rainfall and flood events in steep upland catchments leave geomorphological traces of their occurrence in the form of boulder berms, debris cones, and alluvial fans. Constraining the age of these features is critical to understanding (i) landscape evolution in response to past, present, and future climate changes; and (ii) the magnitude-frequency of extreme, ungauged floods in small upland catchments. This research focuses on the Cambrian Mountains of Wales, UK, where lichenometric dating of geomorphological features and palaeohydrological reconstructions is combined with climatological data and documentary flood records. Our new data from Wales highlight a distinct flood-rich period between 1900 and 1960, similar to many other UK lichen-dated records. However, this study sheds new light on the underlying climatic controls on upland flooding in small catchments. Although floods can occur in any season, their timing is best explained by the Summer North Atlantic Oscillation (SNAO) and shifts between negative (wetter than average conditions with regular cyclonic flow and flooding) and positive phases (drier than average conditions with less frequent cyclonic flow and flooding), which vary from individual summers to decadal and multidecadal periods. Recent wet summer weather, flooding, and boulder-berm deposition in the UK (2007-2012) are related to a pronounced negative phase shift of the SNAO. There is also increasing evidence that recent summer weather extremes in the mid-latitudes may be related to Arctic amplification and rapid sea ice loss. If this is the case, continuing and future climate change is likely to mean that (i) unusual weather patterns become more frequent; and (ii) upland UK catchments will experience heightened flood risk and significant geomorphological changes.

  10. An Assessment of Direct and Indirect Economic Losses of Climatic Extreme Events

    NASA Astrophysics Data System (ADS)

    Otto, C.; Willner, S. N.; Wenz, L.; Levermann, A.

    2015-12-01

    Risk of extreme weather events like storms, heat extremes, and floods has already risen due to anthropogenic climate change and is likely to increase further under future global warming. Additionally, the structure of the global economy has changed importantly in the last decades. In the process of globalization, local economies have become more and more interwoven forming a complex network. Together with a trend towards lean production, this has resulted in a strong dependency of local manufacturers on global supply and value added chains, which may render the economic network more vulnerable to climatic extremes; outages of local manufacturers trigger indirect losses, which spread along supply chains and can even outstrip direct losses. Accordingly, in a comprehensive climate risk assessment these inter-linkages should be considered. Here, we present acclimate, an agent based dynamic damage propagation model. Its agents are production and consumption sites, which are interlinked by economic flows accounting for the complexity as well as the heterogeneity of the global supply network. Assessing the economic response on the timescale of the adverse event, the model permits to study temporal and spatial evolution of indirect production losses during the disaster and in the subsequent recovery phase of the economy. In this study, we focus on the dynamic economic resilience defined here as the ratio of direct to total losses. This implies that the resilience of the system under consideration is low if the high indirect losses are high. We find and assess a nonlinear dependence of the resilience on the disaster size. Further, we analyze the influence of the network structure upon resilience and discuss the potential of warehousing as an adaptation option.

  11. Using a High-Resolution Global Climate Model to Simulate Extreme Extratropical Cyclones

    NASA Astrophysics Data System (ADS)

    Catalano, A. J.; Kapnick, S. B.; Broccoli, A. J.

    2015-12-01

    Extreme coastal storms devastate heavily populated areas around the world. Our understanding of exposure to extreme storms is limited due to the short duration of the observational record, which causes difficulty in assessing their true probability of occurrence. Global climate models provide a means of simulating a much larger sample of extreme events, allowing for better resolution of the tail of the distribution. Both tropical and extratropical cyclones (ETCs) occur over the northwestern Atlantic Ocean, and the risks associated with ETCs can be just as severe as those associated with tropical storms (e.g. high winds, storm surge). Therefore, we examine the ability of a high-resolution coupled atmosphere-ocean general circulation model (GFDL FLOR) to realistically simulate extreme ETCs in the northwestern Atlantic Ocean. We analyze similarities between results from a long (i.e. multi-century) FLOR simulation and several atmospheric reanalysis products. After considering differences in spatial and temporal resolution, results indicate that atmospheric measures of ETC intensity are comparable to those diagnosed from reanalyses. The full 1500-year simulation provides a higher frequency of the strongest intensity measures over the northwestern Atlantic Ocean compared with reanalyses. This illustrates that the larger number of realizations in the simulation provides a better opportunity to sample the tail of the ETC distribution. We further investigate the realism of simulated ETCs by using a tracking algorithm to conduct quantitative comparisons of feature, track, cyclogenesis, and cyclolysis densities of simulated ETC subsamples with storms from recent history (using reanalyses).

  12. Impact of climate extremes on flowering dates of four shrub species

    NASA Astrophysics Data System (ADS)

    Siegmund, Jonatan; Wiedermann, Marc; Donges, Jonathan; Donner, Reik

    2016-04-01

    Ongoing climate change is known to cause an increase in frequency and amplitude of local temperature and precipitation extremes in central Europe. While gradual changes in the climatological conditions are known to strongly influence plant flowering dates, the question arises if and how extremes specifically impact the timing of this important phenological phase. In this study, we systematically quantify simultaneities between meteorological extremes and the timing of flowering of four shrub species across Germany by means of event coincidence analysis, a novel statistical tool that allows assessing whether or not two types of events exhibit similar sequences of occurrences. Additionally we perform a superimposed epoch analysis in order to investigate the impact of different magnitudes of extremes and to assess possible long term influences. Our systematic investigation supports previous findings of experimental studies by highlighting the impact of early spring temperatures on the flowering of wildlife plants. In addition, we find statistically significant indications for some long-term relations reaching back to the previous year.

  13. A climate-based multivariate extreme emulator of met-ocean-hydrological events for coastal flooding

    NASA Astrophysics Data System (ADS)

    Camus, Paula; Rueda, Ana; Mendez, Fernando J.; Tomas, Antonio; Del Jesus, Manuel; Losada, Iñigo J.

    2015-04-01

    Atmosphere-ocean general circulation models (AOGCMs) are useful to analyze large-scale climate variability (long-term historical periods, future climate projections). However, applications such as coastal flood modeling require climate information at finer scale. Besides, flooding events depend on multiple climate conditions: waves, surge levels from the open-ocean and river discharge caused by precipitation. Therefore, a multivariate statistical downscaling approach is adopted to reproduce relationships between variables and due to its low computational cost. The proposed method can be considered as a hybrid approach which combines a probabilistic weather type downscaling model with a stochastic weather generator component. Predictand distributions are reproduced modeling the relationship with AOGCM predictors based on a physical division in weather types (Camus et al., 2012). The multivariate dependence structure of the predictand (extreme events) is introduced linking the independent marginal distributions of the variables by a probabilistic copula regression (Ben Ayala et al., 2014). This hybrid approach is applied for the downscaling of AOGCM data to daily precipitation and maximum significant wave height and storm-surge in different locations along the Spanish coast. Reanalysis data is used to assess the proposed method. A commonly predictor for the three variables involved is classified using a regression-guided clustering algorithm. The most appropriate statistical model (general extreme value distribution, pareto distribution) for daily conditions is fitted. Stochastic simulation of the present climate is performed obtaining the set of hydraulic boundary conditions needed for high resolution coastal flood modeling. References: Camus, P., Menéndez, M., Méndez, F.J., Izaguirre, C., Espejo, A., Cánovas, V., Pérez, J., Rueda, A., Losada, I.J., Medina, R. (2014b). A weather-type statistical downscaling framework for ocean wave climate. Journal of

  14. Altered dynamics of broad-leaved tree species in a Chinese subtropical montane mixed forest: the role of an anomalous extreme 2008 ice storm episode

    PubMed Central

    Ge, Jielin; Xiong, Gaoming; Wang, Zhixian; Zhang, Mi; Zhao, Changming; Shen, Guozhen; Xu, Wenting; Xie, Zongqiang

    2015-01-01

    Extreme climatic events can trigger gradual or abrupt shifts in forest ecosystems via the reduction or elimination of foundation species. However, the impacts of these events on foundation species' demography and forest dynamics remain poorly understood. Here we quantified dynamics for both evergreen and deciduous broad-leaved species groups, utilizing a monitoring permanent plot in a subtropical montane mixed forest in central China from 2001 to 2010 with particular relevance to the anomalous 2008 ice storm episode. We found that both species groups showed limited floristic alterations over the study period. For each species group, size distribution of dead individuals approximated a roughly irregular and flat shape prior to the ice storm and resembled an inverse J-shaped distribution after the ice storm. Furthermore, patterns of mortality and recruitment displayed disequilibrium behaviors with mortality exceeding recruitment for both species groups following the ice storm. Deciduous broad-leaved species group accelerated overall diameter growth, but the ice storm reduced evergreen small-sized diameter growth. We concluded that evergreen broad-leaved species were more susceptible to ice storms than deciduous broad-leaved species, and ice storm events, which may become more frequent with climate change, might potentially threaten the perpetuity of evergreen-dominated broad-leaved forests in this subtropical region in the long term. These results underscore the importance of long-term monitoring that is indispensible to elucidate causal links between forest dynamics and climatic perturbations. PMID:25897387

  15. Altered dynamics of broad-leaved tree species in a Chinese subtropical montane mixed forest: the role of an anomalous extreme 2008 ice storm episode.

    PubMed

    Ge, Jielin; Xiong, Gaoming; Wang, Zhixian; Zhang, Mi; Zhao, Changming; Shen, Guozhen; Xu, Wenting; Xie, Zongqiang

    2015-04-01

    Extreme climatic events can trigger gradual or abrupt shifts in forest ecosystems via the reduction or elimination of foundation species. However, the impacts of these events on foundation species' demography and forest dynamics remain poorly understood. Here we quantified dynamics for both evergreen and deciduous broad-leaved species groups, utilizing a monitoring permanent plot in a subtropical montane mixed forest in central China from 2001 to 2010 with particular relevance to the anomalous 2008 ice storm episode. We found that both species groups showed limited floristic alterations over the study period. For each species group, size distribution of dead individuals approximated a roughly irregular and flat shape prior to the ice storm and resembled an inverse J-shaped distribution after the ice storm. Furthermore, patterns of mortality and recruitment displayed disequilibrium behaviors with mortality exceeding recruitment for both species groups following the ice storm. Deciduous broad-leaved species group accelerated overall diameter growth, but the ice storm reduced evergreen small-sized diameter growth. We concluded that evergreen broad-leaved species were more susceptible to ice storms than deciduous broad-leaved species, and ice storm events, which may become more frequent with climate change, might potentially threaten the perpetuity of evergreen-dominated broad-leaved forests in this subtropical region in the long term. These results underscore the importance of long-term monitoring that is indispensible to elucidate causal links between forest dynamics and climatic perturbations.

  16. Climate change. Six centuries of variability and extremes in a coupled marine-terrestrial ecosystem.

    PubMed

    Black, Bryan A; Sydeman, William J; Frank, David C; Griffin, Daniel; Stahle, David W; García-Reyes, Marisol; Rykaczewski, Ryan R; Bograd, Steven J; Peterson, William T

    2014-09-19

    Reported trends in the mean and variability of coastal upwelling in eastern boundary currents have raised concerns about the future of these highly productive and biodiverse marine ecosystems. However, the instrumental records on which these estimates are based are insufficiently long to determine whether such trends exceed preindustrial limits. In the California Current, a 576-year reconstruction of climate variables associated with winter upwelling indicates that variability increased over the latter 20th century to levels equaled only twice during the past 600 years. This modern trend in variance may be unique, because it appears to be driven by an unprecedented succession of extreme, downwelling-favorable, winter climate conditions that profoundly reduce productivity for marine predators of commercial and conservation interest. PMID:25237100

  17. The Challenges from Extreme Climate Events for Sustainable Development in Amazonia: the Acre State Experience

    NASA Astrophysics Data System (ADS)

    Araújo, M. D. N. M.

    2015-12-01

    In the past ten years Acre State, located in Brazil´s southwestern Amazonia, has confronted sequential and severe extreme events in the form of droughts and floods. In particular, the droughts and forest fires of 2005 and 2010, the 2012 flood within Acre, the 2014 flood of the Madeira River which isolated Acre for two months from southern Brazil, and the most severe flooding throughout the state in 2015 shook the resilience of Acrean society. The accumulated costs of these events since 2005 have exceeded 300 million dollars. For the last 17 years, successive state administrations have been implementing a socio-environmental model of development that strives to link sustainable economic production with environmental conservation, particularly for small communities. In this context, extreme climate events have interfered significantly with this model, increasing the risks of failure. The impacts caused by these events on development in the state have been exacerbated by: a) limitations in monitoring; b) extreme events outside of Acre territory (Madeira River Flood) affecting transportation systems; c) absence of reliable information for decision-making; and d) bureaucratic and judicial impediments. Our experience in these events have led to the following needs for scientific input to reduce the risk of disasters: 1) better monitoring and forecasting of deforestation, fires, and hydro-meteorological variables; 2) ways to increase risk perception in communities; 3) approaches to involve more effectively local and regional populations in the response to disasters; 4) more accurate measurements of the economic and social damages caused by these disasters. We must improve adaptation to and mitigation of current and future extreme climate events and implement a robust civil defense, adequate to these new challenges.

  18. Climate engineering of vegetated land for hot extremes mitigation: an ESM sensitivity study

    NASA Astrophysics Data System (ADS)

    Wilhelm, Micah; Davin, Edouard; Seneviratne, Sonia

    2014-05-01

    Mitigation efforts to reduce anthropogenic climate forcing have thus far proven inadequate, as evident from accelerating greenhouse gas emissions. Many subtropical and mid-latitude regions are expected to experience longer and more frequent heat waves and droughts within the next century. This increased occurrence of weather extremes has important implications for human health, mortality and for socio-economic factors including forest fires, water availability and agricultural production. Various solar radiation management (SRM) schemes that attempt to homogeneously counter the anthropogenic forcing have been examined with different Earth System Models (ESM). Land climate engineering schemes have also been investigated which reduces the amount of solar radiation that is absorbed at the surface. However, few studies have investigated their effects on extremes but rather on mean climate response. Here we present the results of a series of climate engineering sensitivity experiments performed with the Community Earth System Model (CESM) version 1.0.2 at 2°-resolution. This configuration entails 5 fully coupled model components responsible for simulating the Earth's atmosphere, land, land-ice, ocean and sea-ice that interact through a central coupler. Historical and RCP8.5 scenarios were performed with transient land-cover changes and prognostic terrestrial Carbon/Nitrogen cycles. Four sets of experiments are performed in which surface albedo over snow-free vegetated grid points is increased by 0.5, 0.10, 0.15 and 0.20. The simulations show a strong preferential cooling of hot extremes throughout the Northern mid-latitudes during boreal summer. A strong linear scaling between the cooling of extremes and additional surface albedo applied to the land model is observed. The strongest preferential cooling is found in southeastern Europe and the central United States, where increases of soil moisture and evaporative fraction are the largest relative to the control

  19. Assessment of extreme precipitation events over Amazon simulated by global climate models from HIGEM family.

    NASA Astrophysics Data System (ADS)

    Custodio, Maria; Ambrizzi, Tercio; da Rocha, Rosmeri

    2015-04-01

    The variations of extreme climatic events had been described and analyzed in the scientific literature. Both extremes of precipitation and temperature until now are not well represented by regional or global climate models. Additionally, it is important to characterize possible changes in extreme events. The only certainty is that the extreme events such as heat waves, floods, droughts, or storms may imply in severe societal and economical impacts, since they cause significant damage to agriculture, ecology and infrastructure, injury, and loss of life. Therefore, in a scenario of global warming it is necessary understanding and explaining extreme events and to know if global models may represent these events. The South America (SA) climate is characterized by different precipitation regimes and its variability has large influences of the large scale phenomena in the interanual (El Niño South Oscilation - ENSO) and intraseasonal (Maden Julian Oscilation - MJO) timescales. Normally, the AGCM and CGM use low horizontal resolution and present difficult in the representation of these low frequency variability phenomena. The goal of this work is to evaluate the performance of coupled and uncoupled versions of the High-Resolution Global Environmental Model, which will be denominated NUGEM (~60 Km), HiGEM (~90 km) and HadGEM (~135 km) and NUGAM (~60 Km), HiGAM (~90 Km) and HadGAM (~135 Km), respectively, in capturing the signal of interannual and intraseasonal variability of precipitation over Amazon. Basically we want discuss the impact of sea surface temperature in the annual cycle of atmospheric variables. The precipitation time-series were filtered on the interanual (period > 365 days) and intraseasonal (30-90 days) timescales using the Fast Fourier Transform (FFT). The occurrence of extreme precipitation events were analyzed in Amazon region. The criterion for selection of extremes was based on the quartiles of rainfall anomalies in the bands of interest. Both

  20. Cyclone and Anticyclone Activities Impact Eurasian Surface Climate and Cause Extreme Cold Events ?

    NASA Astrophysics Data System (ADS)

    Lu, C.; Zhang, X.; Guan, Z.; Wang, Z.; Qin, Y.

    2014-12-01

    Extreme cold winter weather events have more frequently occurred during recent decades over the Eurasian continent, in conjunction with the rapidly warming Arctic. Although various contributing factors have been examined, including changes in the atmospheric circulation, increase in meridional span of jet stream fluctuation, and anomalous snow and sea ice forcing, it still remains unclear how internally or externally altered large-scale atmospheric dynamics has driven daily-based extreme cold events. In this study, we further investigated variability of and changes in extratropical storm tracks and anticyclones and their resultant dynamic and thermodynamic role in causing extreme cold weathers over Eurasia. The major approach employed is a modified automated cyclone and anticyclone identification and tracking algorithm. Our results reinforced our previous finding that storms have weakened and anticyclones have intensified over Eurasia during 1978/79-2011/2012 winter seasons. Corresponding to these long-term changes, anomalous high pressure occurred over the Ural area, providing fundamental dynamic setting favoring occurrence of blocking events. As a consequence, polar cold air was advected southward to the midlatitude, causing extreme cold events. Along with this dynamic process, snow cover also extended southward to reduce surface absorption of downwelling shortwave radiation and further the cooling process. Barents-Kara sea ice forcing was examined to identify underlying physical mechanisms for changes in storm tracks and anticyclone activities.

  1. Extreme vulnerability of smallholder farmers to agricultural risks and climate change in Madagascar

    PubMed Central

    Harvey, Celia A.; Rakotobe, Zo Lalaina; Rao, Nalini S.; Dave, Radhika; Razafimahatratra, Hery; Rabarijohn, Rivo Hasinandrianina; Rajaofara, Haingo; MacKinnon, James L.

    2014-01-01

    Across the tropics, smallholder farmers already face numerous risks to agricultural production. Climate change is expected to disproportionately affect smallholder farmers and make their livelihoods even more precarious; however, there is limited information on their overall vulnerability and adaptation needs. We conducted surveys of 600 households in Madagascar to characterize the vulnerability of smallholder farmers, identify how farmers cope with risks and explore what strategies are needed to help them adapt to climate change. Malagasy farmers are particularly vulnerable to any shocks to their agricultural system owing to their high dependence on agriculture for their livelihoods, chronic food insecurity, physical isolation and lack of access to formal safety nets. Farmers are frequently exposed to pest and disease outbreaks and extreme weather events (particularly cyclones), which cause significant crop and income losses and exacerbate food insecurity. Although farmers use a variety of risk-coping strategies, these are insufficient to prevent them from remaining food insecure. Few farmers have adjusted their farming strategies in response to climate change, owing to limited resources and capacity. Urgent technical, financial and institutional support is needed to improve the agricultural production and food security of Malagasy farmers and make their livelihoods resilient to climate change. PMID:24535397

  2. The importance of interacting climate modes on Australia’s contribution to global carbon cycle extremes

    PubMed Central

    Cleverly, James; Eamus, Derek; Luo, Qunying; Restrepo Coupe, Natalia; Kljun, Natascha; Ma, Xuanlong; Ewenz, Cacilia; Li, Longhui; Yu, Qiang; Huete, Alfredo

    2016-01-01

    The global carbon cycle is highly sensitive to climate-driven fluctuations of precipitation, especially in the Southern Hemisphere. This was clearly manifested by a 20% increase of the global terrestrial C sink in 2011 during the strongest sustained La Niña since 1917. However, inconsistencies exist between El Niño/La Niña (ENSO) cycles and precipitation in the historical record; for example, significant ENSO–precipitation correlations were present in only 31% of the last 100 years, and often absent in wet years. To resolve these inconsistencies, we used an advanced temporal scaling method for identifying interactions amongst three key climate modes (El Niño, the Indian Ocean dipole, and the southern annular mode). When these climate modes synchronised (1999–2012), drought and extreme precipitation were observed across Australia. The interaction amongst these climate modes, more than the effect of any single mode, was associated with large fluctuations in precipitation and productivity. The long-term exposure of vegetation to this arid environment has favoured a resilient flora capable of large fluctuations in photosynthetic productivity and explains why Australia was a major contributor not only to the 2011 global C sink anomaly but also to global reductions in photosynthetic C uptake during the previous decade of drought. PMID:26976754

  3. Sensitivity of hydrological extremes in climate and land use changes in Belgium

    NASA Astrophysics Data System (ADS)

    Baguis, P.; Roulin, E.

    2009-04-01

    In the present work we analyze, through hydrological modeling, the impacts of climate change on the hydrological extremes in Belgium. The study is carried out for the river Meuse and Scheldt basins in Belgium using the SCHEME hydrological model. The climate change scenarios considered in the analysis have been derived for Belgium from the results of Regional Climate Model simulations that have been performed in the context of the European PRUDENCE project. These simulations are based on the A2 and B2 SRES scenarios. Our approach involves in particular calculation of potential evapotranspiration from all simulations in the PRUDENCE database, based on the Penman equation, as part of the input for the SCHEME model. Furthermore, we consider the hydrological impact of non-meteorological changes and especially of land use changes. Several possibilities of land use in the future are considered in the context of a sensitivity analysis. In both cases of climate and land use change scenarios, the variation in the total streamflow and in the frequency of exceedance of certain thresholds is analyzed.

  4. Extreme vulnerability of smallholder farmers to agricultural risks and climate change in Madagascar.

    PubMed

    Harvey, Celia A; Rakotobe, Zo Lalaina; Rao, Nalini S; Dave, Radhika; Razafimahatratra, Hery; Rabarijohn, Rivo Hasinandrianina; Rajaofara, Haingo; Mackinnon, James L

    2014-04-01

    Across the tropics, smallholder farmers already face numerous risks to agricultural production. Climate change is expected to disproportionately affect smallholder farmers and make their livelihoods even more precarious; however, there is limited information on their overall vulnerability and adaptation needs. We conducted surveys of 600 households in Madagascar to characterize the vulnerability of smallholder farmers, identify how farmers cope with risks and explore what strategies are needed to help them adapt to climate change. Malagasy farmers are particularly vulnerable to any shocks to their agricultural system owing to their high dependence on agriculture for their livelihoods, chronic food insecurity, physical isolation and lack of access to formal safety nets. Farmers are frequently exposed to pest and disease outbreaks and extreme weather events (particularly cyclones), which cause significant crop and income losses and exacerbate food insecurity. Although farmers use a variety of risk-coping strategies, these are insufficient to prevent them from remaining food insecure. Few farmers have adjusted their farming strategies in response to climate change, owing to limited resources and capacity. Urgent technical, financial and institutional support is needed to improve the agricultural production and food security of Malagasy farmers and make their livelihoods resilient to climate change.

  5. Physically Based Simulation of Potential Effects of Carbon Dioxide Altered Climates on Groundwater Recharge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increased concentrations of atmospheric carbon-dioxide (CO2) will alter regional rainfall and potential evapotranspiration regimes that drive groundwater recharge. Improved methods are needed for assessing the potential sensitivities of the soil-water-vegetation system to climate change. This study ...

  6. Trend of climate extremes in North America: A comparison between dynamically downscaled CMIP3 and CMIP5 simulations

    NASA Astrophysics Data System (ADS)

    Castro, C. L.; Chang, H. I.; Mearns, L. O.; Bukovsky, M. S.

    2015-12-01

    Ascertaining the impact of anthropogenically-influenced climate change on climate extremes is of high priority for civil infrastructure and water resource planning. The current future projections based on IPCC models, for example as documented in the recent Climate Change Assessment for the Southwest, indicate a declining trend in precipitation with a warming climate, with associated dramatic reductions in streamflow in the Colorado River basin. However, inconsistent precipitation trends are projected by individual IPCC global climate models (i.e. Sheffield et al. 2013, Bukovsky et al., 2013). The North American Monsoon interannual variability is partly controlled by warm season atmospheric teleconnections emanating from the western tropical Pacific, related to the El Niño Southern Oscillation (ENSO) and Pacific Decadal Variability (PDV). Departure from the ensemble mean approach for long-term climate projection analysis, a physics-based methodology is designed to analyze the relationship between climate extremes and the large scale forcing (Chang et al. 2015). Analysis from the observational record and downscaled CMIP3 regional climate runs has shown intensifying warm season precipitation and temperature extremes following the natural variability of large scale forcing. We will utilize the ongoing community effort in dynamically downscaling the CMIP5 climate projection datasets, part of the North American Coordinated Regional Climate Downscaling Experiment (NA-CORDEX), and compare with the previous generation of CMIP3 downscaled products for future climate assessment. We aim to examine the difference in large scale forcing from different generations of the CMIP models, and the related impact on regional scale climate extreme characteristics.

  7. The impacts of altered tropical cyclone activity on climate mitigation strategies

    NASA Astrophysics Data System (ADS)

    Fisk, J. P.; Hurtt, G. C.; LePage, Y.; Patel, P.; Chini, L. P.; Thomson, A. M.; Clarke, L.; Calvin, K. V.; Wise, M.; Chambers, J. Q.; Negron Juarez, R. I.

    2012-12-01

    There is growing evidence that anthropogenic climate change may alter patterns of tropical cyclone frequency, intensity and spatial distribution, which in turn will alter the carbon balance of terrestrial systems in the large regions impacted by these storms. Recent studies project up to a doubling of major storms (Saffir-Simpson Scale 3-5) over the next century. Single large storms have been shown to be capable of causing committed carbon emissions equivalent to the annual U.S. carbon sink. These changes have the potential to affect climate mitigation strategies, most of which rely on maintaining or enhancing the terrestrial carbon sink to restrain the accumulation of atmospheric greenhouse gases. Altered patterns of disturbances and the resulting changes to the carbon balance of terrestrial systems could impact the magnitude of emissions to mitigate, the economic value of ecosystem carbon storage, and thus future land-use patterns, food prices and energy technology. Here we investigate the potential consequences of altered tropical cyclone activity on climate mitigation strategies using a fully integrated model (iED) that links advanced ecological and socio-economic models. The model combines the regional integrated assessment algorithms of the Global Change Assessment Model (GCAM), with the climate- sensitive ecosystem and carbon modeling in the Ecosystem Demography (ED) model, and the land-use mapping algorithms of the Global Land-use Model (GLM). We explore a range of scenarios of altered future tropical cyclone frequency, intensity and spatial pattern, the resulting effects on the terrestrial carbon balance, and the coupled effects on the food and energy sector under a range of future climate mitigation goals.

  8. The effects of climate change and extreme wildfire events on runoff erosion over a mountain watershed

    NASA Astrophysics Data System (ADS)

    Gould, Gregory K.; Liu, Mingliang; Barber, Michael E.; Cherkauer, Keith A.; Robichaud, Peter R.; Adam, Jennifer C.

    2016-05-01

    Increases in wildfire occurrence and severity under an altered climate can substantially impact terrestrial ecosystems through enhancing runoff erosion. Improved prediction tools that provide high resolution spatial information are necessary for location-specific soil conservation and watershed management. However, quantifying the magnitude of soil erosion and its interactions with climate, hydrological processes, and fire occurrences across a large region (>10,000 km2) is challenging because of the large computational requirements needed to capture the fine-scale complexities of the land surface that govern erosion. We apply the physically-based coupled Variable Capacity Infiltration-Water Erosion Prediction Project (VIC-WEPP) model to study how wildfire occurrences can enhance soil erosion in a future climate over a representative watershed in the northern Rocky Mountains - the Salmon River Basin (SRB) in central Idaho. While the VIC model simulates hydrologic processes at larger scales, the WEPP model simulates erosion at the hillslope scale by sampling representative hillslopes. VIC-WEPP model results indicate that SRB streamflow will have an earlier shift in peak flow by one to two months under future climate scenarios in response to a declining snowpack under warming temperatures. The magnitude of peak flow increases with each higher severity fire scenario; and under the highest fire severity, the peak flow is shifted even earlier, exacerbating the effects of climate change. Similarly, sediment yield also increases with higher fire severities for both historical and future climates. Sediment yield is more sensitive to fire occurrence than to climate change by one to two orders of magnitude, which is not unexpected given that our fire scenarios were applied basin wide as worst case scenarios. In reality, fires only occur over portions of the basin in any given year and subsequent years' vegetation regrowth reduces erosion. However, the effects of climate

  9. The influence of altering push force effectiveness on upper extremity demand during wheelchair propulsion.

    PubMed

    Rankin, Jeffery W; Kwarciak, Andrew M; Mark Richter, W; Neptune, Richard R

    2010-10-19

    Manual wheelchair propulsion has been linked to a high incidence of overuse injury and pain in the upper extremity, which may be caused by the high load requirements and low mechanical efficiency of the task. Previous studies have suggested that poor mechanical efficiency may be due to a low effective handrim force (i.e. applied force that is not directed tangential to the handrim). As a result, studies attempting to reduce upper extremity demand have used various measures of force effectiveness (e.g., fraction effective force, FEF) as a guide for modifying propulsion technique, developing rehabilitation programs and configuring wheelchairs. However, the relationship between FEF and upper extremity demand is not well understood. The purpose of this study was to use forward dynamics simulations of wheelchair propulsion to determine the influence of FEF on upper extremity demand by quantifying individual muscle stress, work and handrim force contributions at different values of FEF. Simulations maximizing and minimizing FEF resulted in higher average muscle stresses (23% and 112%) and total muscle work (28% and 71%) compared to a nominal FEF simulation. The maximal FEF simulation also shifted muscle use from muscles crossing the elbow to those at the shoulder (e.g., rotator cuff muscles), placing greater demand on shoulder muscles during propulsion. The optimal FEF value appears to represent a balance between increasing push force effectiveness to increase mechanical efficiency and minimize upper extremity demand. Thus, care should be taken in using force effectiveness as a metric to reduce upper extremity demand.

  10. Climate-driven ground-level ozone extreme in the fall over the Southeast United States

    PubMed Central

    Wang, Yuhang

    2016-01-01

    Ground-level ozone is adverse to human and vegetation health. High ground-level ozone concentrations usually occur over the United States in the summer, often referred to as the ozone season. However, observed monthly mean ozone concentrations in the southeastern United States were higher in October than July in 2010. The October ozone average in 2010 reached that of July in the past three decades (1980–2010). Our analysis shows that this extreme October ozone in 2010 over the Southeast is due in part to a dry and warm weather condition, which enhances photochemical production, air stagnation, and fire emissions. Observational evidence and modeling analysis also indicate that another significant contributor is enhanced emissions of biogenic isoprene, a major ozone precursor, from water-stressed plants under a dry and warm condition. The latter finding is corroborated by recent laboratory and field studies. This climate-induced biogenic control also explains the puzzling fact that the two extremes of high October ozone both occurred in the 2000s when anthropogenic emissions were lower than the 1980s and 1990s, in contrast to the observed decreasing trend of July ozone in the region. The occurrences of a drying and warming fall, projected by climate models, will likely lead to more active photochemistry, enhanced biogenic isoprene and fire emissions, an extension of the ozone season from summer to fall, and an increase of secondary organic aerosols in the Southeast, posing challenges to regional air quality management. PMID:27551089

  11. Climate-driven ground-level ozone extreme in the fall over the Southeast United States.

    PubMed

    Zhang, Yuzhong; Wang, Yuhang

    2016-09-01

    Ground-level ozone is adverse to human and vegetation health. High ground-level ozone concentrations usually occur over the United States in the summer, often referred to as the ozone season. However, observed monthly mean ozone concentrations in the southeastern United States were higher in October than July in 2010. The October ozone average in 2010 reached that of July in the past three decades (1980-2010). Our analysis shows that this extreme October ozone in 2010 over the Southeast is due in part to a dry and warm weather condition, which enhances photochemical production, air stagnation, and fire emissions. Observational evidence and modeling analysis also indicate that another significant contributor is enhanced emissions of biogenic isoprene, a major ozone precursor, from water-stressed plants under a dry and warm condition. The latter finding is corroborated by recent laboratory and field studies. This climate-induced biogenic control also explains the puzzling fact that the two extremes of high October ozone both occurred in the 2000s when anthropogenic emissions were lower than the 1980s and 1990s, in contrast to the observed decreasing trend of July ozone in the region. The occurrences of a drying and warming fall, projected by climate models, will likely lead to more active photochemistry, enhanced biogenic isoprene and fire emissions, an extension of the ozone season from summer to fall, and an increase of secondary organic aerosols in the Southeast, posing challenges to regional air quality management.

  12. Assessing the Land-Ocean Interaction under Extreme Climate Change Condition - a Modeling Approach

    NASA Astrophysics Data System (ADS)

    Yang, Z.; Wang, T.; Leung, R.; Balaguru, K.; Hibbard, K. A.

    2011-12-01

    Many modeling applications, at global and regional scales, have demonstrated that numerical models are useful tools to quantify the uncertainty and the interactions between natural physical and biogeochemical processes and human activities in coastal regions. A regional integrated assessment modeling framework to investigate the interactions of agriculture and land use, coastal ecological issues, energy supply and effects of climate changes is under development by Pacific Northwest National Laboratory (PNNL), with specific application to the Gulf of Mexico. The Gulf is vulnerable to the direct impacts of climate changes, such as sea level rise, hurricane-induced storm surge and extreme floods due to high precipitation and river run-off. This presentation will focus on the coastal modeling aspect of this integrated modeling approach. An unstructured-grid finite volume coastal ocean model, which has the capability of simulating coastal circulation, wave and storm surges, sediment transport and biogeochemical processes, is applied to simulate hurricane storm surges and extreme flood events in the coastal region of Gulf of Mexico. Specifically, storm surge along the US Southeast coasts and freshwater plume in the Mississippi Delta were simulated and compared to observations. Numerical sensitivity studies with boundary conditions and forcing indicated the urgent need of a real observation network as well as the importance of accurate model predictions at regional scales to drive the model at smaller scales. The implication of natural pressures, such as storm surge and flooding to biogeochemical processes and marine ecosystem will be discussed.

  13. Climate-driven ground-level ozone extreme in the fall over the Southeast United States.

    PubMed

    Zhang, Yuzhong; Wang, Yuhang

    2016-09-01

    Ground-level ozone is adverse to human and vegetation health. High ground-level ozone concentrations usually occur over the United States in the summer, often referred to as the ozone season. However, observed monthly mean ozone concentrations in the southeastern United States were higher in October than July in 2010. The October ozone average in 2010 reached that of July in the past three decades (1980-2010). Our analysis shows that this extreme October ozone in 2010 over the Southeast is due in part to a dry and warm weather condition, which enhances photochemical production, air stagnation, and fire emissions. Observational evidence and modeling analysis also indicate that another significant contributor is enhanced emissions of biogenic isoprene, a major ozone precursor, from water-stressed plants under a dry and warm condition. The latter finding is corroborated by recent laboratory and field studies. This climate-induced biogenic control also explains the puzzling fact that the two extremes of high October ozone both occurred in the 2000s when anthropogenic emissions were lower than the 1980s and 1990s, in contrast to the observed decreasing trend of July ozone in the region. The occurrences of a drying and warming fall, projected by climate models, will likely lead to more active photochemistry, enhanced biogenic isoprene and fire emissions, an extension of the ozone season from summer to fall, and an increase of secondary organic aerosols in the Southeast, posing challenges to regional air quality management. PMID:27551089

  14. Climatic extreme events combine with impacts of gradual climate change: recent evidence from the Andes and the Alps

    NASA Astrophysics Data System (ADS)

    Huggel, Christian; Giráldez, Claudia; Haeberli, Wilfried; Schneider, Demian; Frey, Holger; Schaub, Yvonne; Cochachin, Alejo; Portocarrero, Cesar; García, Javier; Guillén Ludeña, Sebastián; Rohrer, Mario; McArdell, Brian

    2013-04-01

    In high-mountain areas climatic extreme events can combine with effects of gradual climate change to form cascading processes, occasionally resulting in major disasters. Heavy precipitation events thereby evolve into mass movement processes such as landslides, avalanches and debris flows that can devastate urban areas at the foot of mountains. The transformation and interaction of processes are complex and often not sufficiently understood or difficult to predict, and thus more research is needed. Of particular concern are landslide impacts into existing or new glacier lakes from destabilized mountain flanks in relation with glacier retreat and permafrost degradation. Here we analyze a number of recent events in the Andes of Peru and compare them with observations in the Alps in Europe. In southern Peru debris flow events that were among the largest recent ones worldwide remained largely unstudied although they destroyed entire towns and important traffic and energy infrastructure. We used a combination of field work, satellite images, satellite rainfall data and available meteorological stations as well as numerical modeling to reconstruct origin, type and effect of these events. Large sediment deposits resulting from deglaciation processes represent a key factor, and were mobilized by heavy rainfall events. Tens of millions of m3 sediment were transported downstream in single events, with compound effects on downstream river systems causing destruction and inundation. Other recent events in Peru underline the importance of a cascade of process interaction, with ice avalanches impacting glacier lakes, triggering flood waves and debris flows that travel downstream and eventually impact urban areas. In the Alps recent observations indicate an increase of occurrence of complex compound processes with short-term climatic events overprinting on longer-term effects of gradual climate change (e.g. from glacier retreat and permafrost degradation). Especially important are

  15. Robust Estimation of Precipitation Extremes from Short-Period Regional Climate Downscales

    NASA Astrophysics Data System (ADS)

    Apling, D.; Darmenova, K.; Higgins, G. J.

    2011-12-01

    The US Southwest is likely to experience significant changes in precipitation patterns in coming decades as a result of regional climate change. One serious issue is to better understand extreme precipitation events, which affect infrastructure planning, and human life and safety management. Extreme precipitation events are characterized by the maximum expectation of accumulated precipitation over a short time period, which has a long-period return over some number of years; e.g., the 100-year return of daily precipitation. These measures are statistics drawn from Extreme Value Theory, and can be challenging to accurately and reliably estimate for short data sets. Regional Climate Models (RCM) are often run for shorter decadal periods, both to economize on computational expense, and to characterize specific decadal time bands. In each case, one needs robust statistical estimation algorithms to accurately and reliably retrieve the precipitation recurrence statistics. To produce these important decision-aiding products, we added several processes to an otherwise conventional Peaks Over Threshold technique operating on the combined grid-scale and cumuliform precipitation outputs from our 12 kilometer Weather Research and Forecasting (WRF) downscale of the National Centers for Environmental Prediction (NCEP) reanalysis fields for the ten year period of 2000-2009 over the Southwest US. These processes included interleaved sub-year intermediate aggregations, correlated sample corrections, distributional tail feature extraction, and trimmed set tail fitting with jackknife error estimation. The process resulted in estimated 100-year return 24-hour accumulated precipitation expectations with accompanying error bounds, which compare well to established historical precipitation statistics.

  16. Climate Change Alters Seedling Emergence and Establishment in an Old-Field Ecosystem

    SciTech Connect

    Classen, Aimee T; Norby, Richard J; Campany, Courtney E; Sides, Katherine E; Weltzin, Jake

    2010-01-01

    In shaping how ecosystems respond to climatic change, ecosystem structure can dominate over physiological responses of individuals, especially under conditions of multiple, simultaneous changes in environmental factors. Ecological succession drives large-scale changes in ecosystem structure over time, but the mechanisms whereby climatic change alters succession remain unresolved. Here, we investigate effects of atmospheric and climatic change on seedling establishment, recognizing that small shifts in seedling establishment of different species may have long-term repercussions on the transition of fields to forests in the future. Our 4-year experiment in an old-field ecosystem revealed that response of seedling emergence to different combinations of atmospheric CO2 concentration, air temperature, and soil moisture depends on seed phenology, the timing of seed arrival into an ecosystem. We conclude that seed phenology is an important plant trait that can shape, and help predict, the trajectories of ecosystems under climatic change.

  17. Magnitude of extreme heat waves in present climate and their projection in a warming world

    NASA Astrophysics Data System (ADS)

    Russo, Simone; Dosio, Alessandro; Graversen, Rune G.; Sillmann, Jana; Carrao, Hugo; Dunbar, Martha B.; Singleton, Andrew; Montagna, Paolo; Barbola, Paulo; Vogt, Jürgen V.

    2014-11-01

    An extreme heat wave occurred in Russia in the summer of 2010. It had serious impacts on humans and natural ecosystems, it was the strongest recorded globally in recent decades and exceeded in amplitude and spatial extent the previous hottest European summer in 2003. Earlier studies have not succeeded in comparing the magnitude of heat waves across continents and in time. This study introduces a new Heat Wave Magnitude Index that can be compared over space and time. The index is based on the analysis of daily maximum temperature in order to classify the strongest heat waves that occurred worldwide during the three study periods 1980-1990, 1991-2001, and 2002-2012. In addition, multimodel ensemble outputs from the Coupled Model Intercomparison Project Phase 5 are used to project future occurrence and severity of heat waves, under different Representative Concentration Pathways, adopted by the Intergovernmental Panel on Climate Change for its Fifth Assessment Report (AR5). Results show that the percentage of global area affected by heat waves has increased in recent decades. Moreover, model predictions reveal an increase in the probability of occurrence of extreme and very extreme heat waves in the coming years, in particular, by the end of this century, under the most severe IPCC AR5 scenario, events of the same severity as that in Russia in the summer of 2010 will become the norm and are projected to occur as often as every 2 years for regions such as southern Europe, North America, South America, Africa, and Indonesia.

  18. Whole-system responses of experimental plant communities to climate extremes imposed in different seasons.

    PubMed

    De Boeck, Hans J; Dreesen, Freja E; Janssens, Ivan A; Nijs, Ivan

    2011-02-01

    • Discrete climate events such as heat waves and droughts can have a disproportionate impact on ecosystems relative to the temporal scale over which they occur. Research oriented towards (extreme) events rather than (gradual) trends is therefore urgently needed. • Here, we imposed heat waves and droughts (50-yr return time) in a full factorial design on experimental plant communities in spring, summer or autumn. Droughts were created by removing the controlled water table (rainout shelters prevented precipitation), while heat waves were imposed with infrared heaters. • Measurements of whole-system CO(2) exchange, growth and biomass production revealed multiple interactions between treatments and the season in which they occurred. Heat waves had only small and transient effects, with infrared imaging showing little heat stress because of transpirational cooling. If heat waves were combined with drought, negative effects observed in single factor drought treatments were exacerbated through intensified soil drying, and heat stress in summer. Plant recovery from stress differed, affecting the biomass yield. • In conclusion, the timing of extreme events is critical regarding their impact, and synergisms between heat waves and drought aggravate the negative effects of these extremes on plant growth and functioning.

  19. A vulnerability tool for adapting water and aquatic resources to climate change and extremes on the Shoshone National Forest, Wyoming

    NASA Astrophysics Data System (ADS)

    Rice, J.; Joyce, L. A.; Armel, B.; Bevenger, G.; Zubic, R.

    2011-12-01

    Climate change introduces a significant challenge for land managers and decision makers managing the natural resources that provide many benefits from forests. These benefits include water for urban and agricultural uses, wildlife habitat, erosion and climate control, aquifer recharge, stream flows regulation, water temperature regulation, and cultural services such as outdoor recreation and aesthetic enjoyment. The Forest Service has responded to this challenge by developing a national strategy for responding to climate change (the National Roadmap for Responding to Climate Change, July 2010). In concert with this national strategy, the Forest Service's Westwide Climate Initiative has conducted 4 case studies on individual Forests in the western U.S to develop climate adaptation tools. Western National Forests are particularly vulnerable to climate change as they have high-mountain topography, diversity in climate and vegetation, large areas of water limited ecosystems, and increasing urbanization. Information about the vulnerability and capacity of resources to adapt to climate change and extremes is lacking. There is an urgent need to provide customized tools and synthesized local scale information about the impacts to resources from future climate change and extremes, as well as develop science based adaptation options and strategies in National Forest management and planning. The case study on the Shoshone National Forest has aligned its objectives with management needs by developing a climate extreme vulnerability tool that guides adaptation options development. The vulnerability tool determines the likely degree to which native Yellowstone cutthroat trout and water availability are susceptible to, or unable to cope with adverse effects of climate change extremes. We spatially categorize vulnerability for water and native trout resources using exposure, sensitivity, and adaptive capacity indicators that use minimum and maximum climate and GIS data. Results

  20. Climate Change and Health Risks from Extreme Heat and Air Pollution in the Eastern United States

    NASA Astrophysics Data System (ADS)

    Limaye, V.; Vargo, J.; Harkey, M.; Holloway, T.; Meier, P.; Patz, J.

    2013-12-01

    Climate change is expected to exacerbate health risks from exposure to extreme heat and air pollution through both direct and indirect mechanisms. Directly, warmer ambient temperatures promote biogenic emissions of ozone precursors and favor the formation of ground-level ozone, while an anticipated increase in the frequency of stagnant air masses will allow fine particulates to accumulate. Indirectly, warmer summertime temperatures stimulate energy demand and exacerbate polluting emissions from the electricity sector. Thus, while technological adaptations such as air conditioning can reduce risks from exposures to extreme heat, they can trigger downstream damage to air quality and public health. Through an interdisciplinary modeling effort, we quantify the impacts of climate change on ambient temperatures, summer energy demand, air quality, and public health. The first phase of this work explores how climate change will directly impact the burden of heat-related mortality. Climatic patterns, demographic trends, and epidemiologic risk models suggest that populations in the eastern United States are likely to experience an increasing heat stress mortality burden in response to rising summertime air temperatures. We use North American Regional Climate Change Assessment Program modeling data to estimate mid-century 2-meter air temperatures and humidity across the eastern US from June-August, and quantify how long-term changes in actual and apparent temperatures from present-day will affect the annual burden of heat-related mortality across this region. With the US Environmental Protection Agency's Environmental Benefits Mapping and Analysis Program, we estimate health risks using concentration-response functions, which relate temperature increases to changes in annual mortality rates. We compare mid-century summertime temperature data, downscaled using the Weather Research and Forecasting model, to 2007 baseline temperatures at a 12 km resolution in order to estimate

  1. Alterations in flowering strategies and sexual allocation of Caragana stenophylla along a climatic aridity gradient

    PubMed Central

    Xie, Lina; Guo, Hongyu; Ma, Chengcang

    2016-01-01

    Plant can alter reproductive strategies for adaptation to different environments. However, alterations in flowering strategies and sexual allocation for the same species growing in different environments still remain unclear. We examined the sexual reproduction parameters of Caragana stenophylla across four climatic zones from semi-arid, arid, very arid, to intensively arid zones in the Inner Mongolia Steppe, China. Under the relatively favorable climatic conditions of semi-arid zone, C. stenophylla took a K-strategy for flowering (fewer but bigger flowers, and higher seed set). In contrast, under the harsher climatic conditions of intensively arid zone, C. stenophylla took an r-strategy for flowering (more but smaller flowers, and lower seed set). In arid and very arid zones, C. stenophylla exhibited intermediate flowering strategies between K- and r-strategies. In semi-arid, arid and very arid zones, sexual allocation and sexual allocation efficiency (SAE) of C. stenophylla were high, and the population recruitment might be mainly through sexual reproduction; in intensively arid zone, however, sexual allocation and SAE were very low, seed production was very limited, and clonal reproduction might compensate for the decrease in sexual reproduction. Our results suggested that C. stenophylla adapted to the climatic aridity gradient by alterations in flowering strategies and reproductive allocation. PMID:27628093

  2. Alterations in flowering strategies and sexual allocation of Caragana stenophylla along a climatic aridity gradient.

    PubMed

    Xie, Lina; Guo, Hongyu; Ma, Chengcang

    2016-01-01

    Plant can alter reproductive strategies for adaptation to different environments. However, alterations in flowering strategies and sexual allocation for the same species growing in different environments still remain unclear. We examined the sexual reproduction parameters of Caragana stenophylla across four climatic zones from semi-arid, arid, very arid, to intensively arid zones in the Inner Mongolia Steppe, China. Under the relatively favorable climatic conditions of semi-arid zone, C. stenophylla took a K-strategy for flowering (fewer but bigger flowers, and higher seed set). In contrast, under the harsher climatic conditions of intensively arid zone, C. stenophylla took an r-strategy for flowering (more but smaller flowers, and lower seed set). In arid and very arid zones, C. stenophylla exhibited intermediate flowering strategies between K- and r-strategies. In semi-arid, arid and very arid zones, sexual allocation and sexual allocation efficiency (SAE) of C. stenophylla were high, and the population recruitment might be mainly through sexual reproduction; in intensively arid zone, however, sexual allocation and SAE were very low, seed production was very limited, and clonal reproduction might compensate for the decrease in sexual reproduction. Our results suggested that C. stenophylla adapted to the climatic aridity gradient by alterations in flowering strategies and reproductive allocation. PMID:27628093

  3. Changing precipitation extremes in a warming climate: A basis for design flood estimation

    NASA Astrophysics Data System (ADS)

    Wasko, Conrad; Sharma, Ashish

    2016-04-01

    The potential for increasing intensity of future rainfall events has significant implications for flooding and the design of infrastructure. However the questions of how precipitation will change in the future, how important these changes are to flooding, and how engineers incorporate these changes into hydrologic design remain as open questions. In the absence of reliable point based estimates of how precipitation will change, many studies investigate the historical relationship between rainfall intensity and temperature as a proxy for what may happen in a warmer climate. Much of the research to date has focussed on changing precipitation intensity, however, temporal and spatial patterns of precipitation are just as important. Here we link higher temperatures to changes in temporal and spatial patterns of extreme precipitation events. We show, using observed high quality precipitation records from Australia covering all major climatic zones, that storms are intensifying in both time and space resulting in a greater potential for flooding especially in urban locales around the world. Given that precipitation and antecedent conditions are changing, and, the impacts to flooding are significant, methods of incorporating these changes in catchment modelling are required. Continuous simulation offers a natural flexibility to incorporate the many correlated changes in precipitation that may occur in a future climate. An argument for such a framework using existing continuous simulation alternatives is articulated in concluding this presentation.

  4. Trend analysis of extreme climate indices using simulated temperature and precipitation time series for the Carpathian basin

    NASA Astrophysics Data System (ADS)

    Pongracz, R.; Bartholy, J.; Szabo, P.; Kovacs, G.

    2009-09-01

    Global warming may be recognized both in shifts of regional mean climate, and also, in the frequency and intensity changes of different climate extremes. Several climate extreme indices are analyzed and compared for the Carpathian basin (located in Central/Eastern Europe) following the guidelines suggested by the joint WMO-CCl/CLIVAR Working Group on climate change detection. Our statistical trend analysis includes the evaluation of several extreme temperature and precipitation indices using different threshold values. In order to evaluate the expected trends (by 2071-2100 relative to the 1961-1990 reference period) in the Carpathian basin, daily values of meteorological variables are obtained from the outputs of various regional climate model (RCM) experiments accomplished in the frame of the completed EU-project PRUDENCE (Prediction of Regional scenarios and Uncertainties for Defining EuropeaN Climate change risks and Effects). Horizontal resolution of the applied RCMs is 50 km. Two emission scenarios (A2 and B2) are used to compare past and future simulated values of the extreme climate indices for the Carpathian basin. Furthermore, fine-resolution climate experiments of two additional RCMs adapted and run at the Department of Meteorology, Eotvos Lorand University are used to extend the trend analysis of climate extremes for the Carpathian basin. (1) Model PRECIS (run at 25 km horizontal resolution) was developed at the UK Met Office, Hadley Centre, and it uses the boundary conditions from the HadCM3 GCM. (2) Model RegCM3 (run at 10 km horizontal resolution) was developed by Giorgi et al. and it is available from the ICTP (International Centre for Theoretical Physics). Analysis of the simulated daily temperature datasets suggests that the detected regional warming is expected to continue in the 21st century. Cold temperature extremes are projected to decrease while warm extremes tend to increase significantly. Expected changes of annual precipitation indices are

  5. Predicted responses of arctic and alpine ecosystems to altered seasonality under climate change.

    PubMed

    Ernakovich, Jessica G; Hopping, Kelly A; Berdanier, Aaron B; Simpson, Rodney T; Kachergis, Emily J; Steltzer, Heidi; Wallenstein, Matthew D

    2014-10-01

    Global climate change is already having significant impacts on arctic and alpine ecosystems, and ongoing increases in temperature and altered precipitation patterns will affect the strong seasonal patterns that characterize these temperature-limited systems. The length of the potential growing season in these tundra environments is increasing due to warmer temperatures and earlier spring snow melt. Here, we compare current and projected climate and ecological data from 20 Northern Hemisphere sites to identify how seasonal changes in the physical environment due to climate change will alter the seasonality of arctic and alpine ecosystems. We find that although arctic and alpine ecosystems appear similar under historical climate conditions, climate change will lead to divergent responses, particularly in the spring and fall shoulder seasons. As seasonality changes in the Arctic, plants will advance the timing of spring phenological events, which could increase plant nutrient uptake, production, and ecosystem carbon (C) gain. In alpine regions, photoperiod will constrain spring plant phenology, limiting the extent to which the growing season can lengthen, especially if decreased water availability from earlier snow melt and warmer summer temperatures lead to earlier senescence. The result could be a shorter growing season with decreased production and increased nutrient loss. These contrasting alpine and arctic ecosystem responses will have cascading effects on ecosystems, affecting community structure, biotic interactions, and biogeochemistry.

  6. Polar endoliths - an anti-correlation of climatic extremes and microbial biodiversity

    NASA Astrophysics Data System (ADS)

    Cockell, Charles S.; McKay, Christopher P.; Omelon, Christopher

    2002-10-01

    We examined the environmental stresses experienced by cyanobacteria living in endolithic gneissic habitats in the Haughton impact structure, Devon Island, Canadian High Arctic (75° N) and compared them with the endolithic habitat at the opposite latitude in the Dry Valleys of Antarctica (76° S). In the Arctic during the summer, there is a period for growth of approximately 2.5 months when temperatures rise above freezing. During this period, freeze thaw can occur during the diurnal cycle, but freeze thaw excursions are rare within higher-frequency temperature changes on the scale of minutes, in contrast with the Antarctic Dry Valleys. In the Arctic location rainfall of approximately 3 mm can occur in a single day and provides moisture for endolithic organisms for several days afterwards. This rainfall is an order of magnitude higher than that received in the Dry Valleys over 1 year. In the Dry Valleys, endolithic communities may potentially receive higher levels of ultraviolet radiation than the Arctic location because ozone depletion is more extreme. The less extreme environmental stresses experienced in the Arctic are confirmed by the presence of substantial epilithic growth, in contrast to the Dry Valleys. Despite the more extreme conditions experienced in the Antarctic location, the diversity of organisms within the endolithic habitat, which includes lichen and eukaryotic algal components, is higher than observed at the Arctic location, where genera of cyanobacteria dominate. The lower biodiversity in the Arctic may reflect the higher water flow through the rocks caused by precipitation and the more heterogeneous physical structure of the substrate. The data illustrate an instance in which extreme climate is anti-correlated with microbial biological diversity.

  7. Impacts of climate change on precipitation and discharge extremes through the use of statistical downscaling approaches in a Mediterranean basin.

    PubMed

    Piras, Monica; Mascaro, Giuseppe; Deidda, Roberto; Vivoni, Enrique R

    2016-02-01

    Mediterranean region is characterized by high precipitation variability often enhanced by orography, with strong seasonality and large inter-annual fluctuations, and by high heterogeneity of terrain and land surface properties. As a consequence, catchments in this area are often prone to the occurrence of hydrometeorological extremes, including storms, floods and flash-floods. A number of climate studies focused in the Mediterranean region predict that extreme events will occur with higher intensity and frequency, thus requiring further analyses to assess their effect at the land surface, particularly in small- and medium-sized watersheds. In this study, climate and hydrologic simulations produced within the Climate Induced Changes on the Hydrology of Mediterranean Basins (CLIMB) EU FP7 research project were used to analyze how precipitation extremes propagate into discharge extremes in the Rio Mannu basin (472.5km(2)), located in Sardinia, Italy. The basin hydrologic response to climate forcings in a reference (1971-2000) and a future (2041-2070) period was simulated through the combined use of a set of global and regional climate models, statistical downscaling techniques, and a process based distributed hydrologic model. We analyzed and compared the distribution of annual maxima extracted from hourly and daily precipitation and peak discharge time series, simulated by the hydrologic model under climate forcing. For this aim, yearly maxima were fit by the Generalized Extreme Value (GEV) distribution using a regional approach. Next, we discussed commonality and contrasting behaviors of precipitation and discharge maxima distributions to better understand how hydrological transformations impact propagation of extremes. Finally, we show how rainfall statistical downscaling algorithms produce more reliable forcings for hydrological models than coarse climate model outputs.

  8. Analyses of climate and extreme indices in Central and Eastern Europe within the CECILIA project

    NASA Astrophysics Data System (ADS)

    Hirschi, M.; Boberg, F.; Christensen, O. B.; Seneviratne, S. I.; Stepanek, P.; Wp4 Members, Cecilia

    2009-04-01

    The EU-project CECILIA (Central and Eastern Europe Climate Change Impact and VulnerabiLIty Assessment) aims at delivering a climate change impacts and vulnerability assessment in targeted areas of Central and Eastern Europe. This region appears particularly vulnerable with regard to future changes in extremes (Christensen and Christensen 2003, Schär et al. 2004), likely due to regional specificities such as highly varying topography and continentality, and due to changes in soil moisture content (Seneviratne et al. 2006). In the project, emphasis is given to applications of regional climate modeling studies at a resolution of 10 km for local impact studies in key sectors of the region. The project includes the analysis of extreme weather events in present day and future climate in the target region. For this purpose, an extensive list of precipitation and temperature indices was defined. Observational data used for the indices calculation comes from the European Climate Assessment & Dataset project (ECA&D, Klein Tank et al. 2002), from the ENSEMBLES gridded observations (E-Obs, Haylock et al. 2008), and from station data of the local partners in Central and Eastern Europe. Moreover, the same indices were calculated consistently for a selection of pre-existing RCM datasets (PRUDENCE, ENSEMBLES), and for the CECILIA driving models. Later on, the 10 km high-resolution climate simulations from CECILIA will be included in the analysis. Here we focus on the analysis of a selection of temperature indices, and on the validation of the model-derived indices with the observations. Generally, the spatial agreement between the models and the observations is very good for mean, maximum and minimum temperature (both in terms of the spatial variability and the spatial correlation). The spread between the models is larger for the daily temperature range, with most models showing larger spatial variability compared to the observations. When it comes to heat and cold wave indices

  9. Gender and occupational perspectives on adaptation to climate extremes in the Afram Plains of Ghana

    USGS Publications Warehouse

    Codjoe, Samuel N.A.; Atidoh, Lucy K.; Burkett, Virginia

    2012-01-01

    Although sub-Saharan Africa does not contribute significantly to greenhouse gas emissions, significant adverse impacts of climate change are anticipated in this region. Countries in West Africa, which are heavily dependent on rain-fed agriculture, are projected to experience more frequent and intense droughts, altered rainfall patterns and increases in temperature through the end of this century. Changes in hydrology and temperature are likely to affect crop yields, thereby placing pressure on scarce resources in a region that is characterised by limited social, political, technical and financial resources. The success with which communities cope with the impacts of climate change is influenced by existing conditions, forces and characteristics which are peculiar to each of these communities. This paper assesses the preferred adaptation strategies during floods and droughts of males and females in three different occupations (farming, fishing, and charcoal production). Findings are based upon an analysis of focus group discussions and a ranking of preferred adaptation options in three communities in the Afram Plains of Ghana. Assessments of this nature should aid in the selection and implementation of adaptation options for communities and households, which is the level at which climate change adaptation is likely to occur in West Africa.

  10. Tree growth and forest ecosystem functioning in Eurasia under extreme climate conditions

    NASA Astrophysics Data System (ADS)

    Saurer, Matthias; Kirdyanov, Alexander; Prokushkin, Anatoly; Bryukhanova, Marina; Knorre, Anastasia; Nasyrov, Muhtor; Frank, David; Treydte, Kerstin; Sidorova, Olga; Siegwolf, Rolf

    2013-04-01

    The main goal of this study is to improve our understanding of the influence of a changing climate on trees in extreme conditions by a detailed analysis of the factors controlling tree-ring growth. We investigated forest ecosystems in regions that are very sensitive to climatic changes and where rapid and dramatic environmental and climatic changes are on-going, namely, the high latitude permafrost region in Central Siberia (Russia), the semi-arid dry areas in Central Asia (Uzbekistan) and high-altitude sites in the Alps (Switzerland). Tree-ring parameters studied were ring-width, density, cell number and structure and the ratio of carbon and oxygen isotopes. An important aspect of the work was the characterization of seasonal growth and water supply of trees. Intra-seasonal dynamics of tree-ring formation was correlated with monitored environmental factors, such as air and soil temperature and moisture, permafrost depth and the isotope composition of soil water, of precipitation, and of stream water. Intra-annual and long-term variability of the main tree-ring parameters were compared for the different regions. The results obtained help us to understand better tree-physiological processes valid under contrasting environmental conditions. For instance, the relationship between the onset of cell division in the cambium and the thermo-hydrological soil regime was used to determine the period of the year with the highest influence on the start of tree-ring formation. Seasonally resolved oxygen isotope depth profiles of soil water and concurrent xylem and leaf water measurements show the importance of time-lags between precipitation, leaf processes and growth. The data obtained are important for improving tree-ring growth models and estimating future tree growth under climate change. Funding: SNF SCOPES IZ73Z0_128035

  11. Atmospheric Extremes in a Changing Climate: A Strategy for Improved Understanding Driven by International Security Concerns

    NASA Astrophysics Data System (ADS)

    Davis, A. B.; Kao, C. J.

    2001-05-01

    critical threshold crossing. So extreme atmospheric phenomena are of the essence yet they are poorly understood, even in a steady climate, because they challenge both dynamical modelers and statisticians. The authors will describe a preliminary proposal to harness some of the unique human, computational and observational resources at LANL that could lead to a significant breakthrough in our understanding of extreme weather mechanisms and how they relate to climate and climate change. If implemented, this program could open new relationships between the laboratory and presently unsuspecting client-agencies such as FEMA, CDC, EPA, State Department, and so on.

  12. Role of Soils in Hydrologic Response to Climate Extremes and Land Use Change

    NASA Astrophysics Data System (ADS)

    Scanlon, B. R.; Zhang, Z.; Save, H.; Reedy, R. C.; Faunt, C. C.

    2015-12-01

    Increasing demand for water in response to growing global population underscores the need to better understand linkages and feedbacks between land surface processes and water resources to manage water resources more sustainably. Here we examine the role of soils on hydrologic response to climate extremes and land use change using field scale and remote sensing data at point to basin scales in the U.S. High Plains and California Central Valley. In the U.S. High Plains, soil-textural variations make the difference between sustainable water resources related to coarse-grained soils in the northern High Plains and groundwater mining associated with fine-grained soils in much of the central and southern High Plains. Field data show dynamic response of water resources to droughts and land use change in the northern High Plains with limited response in much of the central and southern High Plains. Soil profiles provide a key to the past by archiving system response to environmental changes in subsurface soil physics and environmental tracer data. Areas with coarse-grained soils are vulnerable to reduced recharge during droughts and increased recharge with land use change from perennial to annual vegetation whereas fine-grained soils are generally insensitive to these stresses. GRACE satellite monitoring of total water storage variations in response to recent droughts is consistent with these spatial variations in soils across the High Plains and hydrologic response to droughts.In the California Central Valley, coarse grained soils in alluvial basins result in dynamic hydrologic responses to climate extremes. GRACE satellite data show marked depletion in total water storage in response to recent droughts reflecting groundwater and surface reservoir storage declines consistent with regional groundwater modeling and monitoring data. The coarse alluvial soils typical of much of the region facilitate managed aquifer recharge in depleted aquifers to complement surface reservoir

  13. Changes in climate extremes and their impacts on the natural physical environment: An overview of the IPCC SREX report

    NASA Astrophysics Data System (ADS)

    Seneviratne, S. I.; Nicholls, N.; Easterling, D.; Goodess, C. M.; Kanae, S.; Kossin, J.; Luo, Y.; Marengo, J.; McInnes, K.; Rahimi, M.; Reichstein, M.; Sorteberg, A.; Vera, C.; Zhang, X.

    2012-04-01

    In April 2009, the Intergovernmental Panel on Climate Change (IPCC) decided to prepare a new special report with involvement of the UN International Strategy for Disaster Reduction (ISDR) on the topic "Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation" (SREX, http://ipcc-wg2.gov/SREX/). This special report reviews the scientific literature on past and projected changes in weather and climate extremes, and the relevance of such changes to disaster risk reduction and climate change adaptation. The SREX Summary for Policymakers was approved at an IPCC Plenary session on November 14-18, 2011, and the full report is planned for release in February 2012. This presentation will provide an overview on the structure and contents of the SREX, focusing on Chapter 3: "Changes in climate extremes and their impacts on the natural physical environment" [1]. It will in particular present the main findings of the chapter, including differences between the SREX's conclusions and those of the IPCC Fourth Assessment of 2007, and the implications of this new assessment for disaster risk reduction. Finally, aspects relevant to impacts on the biogeochemical cycles will also be addressed. [1] Seneviratne, S.I., N. Nicholls, D. Easterling, C.M. Goodess, S. Kanae, J. Kossin, Y. Luo, J. Marengo, K. McInnes, M. Rahimi, M. Reichstein, A. Sorteberg, C. Vera, and X. Zhang, 2012: Changes in climate extremes and their impacts on the natural physical environment. In: Intergovernmental Panel on Climate Change Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation [Field, C. B., Barros, V., Stocker, T.F., Qin, D., Dokken, D., Ebi, K.L., Mastrandrea, M. D., Mach, K. J., Plattner, G.-K., Allen, S. K., Tignor, M. and P. M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA

  14. Weather and Climatic Drivers of Extreme Flooding Events over the Midwest of the United States

    NASA Astrophysics Data System (ADS)

    Robertson, A. W.; Lall, U.; Kushnir, Y.; Nakamura, J.

    2012-12-01

    There is an urgent need to better understand how partly predictable modes of climate variability impact the probability of flood events in space and time, across multiple time scales, from weekly to seasonal, interannual and beyond. Climate undergoes natural fluctuations through persistent and oscillatory regimes at intraseasonal (e.g., the 30--60 day Madden Julian Oscillation, MJO), interannual (e.g., the El Niño-Southern Oscillation, ENSO) timescales, as well as decadal and longer (e.g., the Pacific Decadal Oscillation, PDO), and as a function of anthropogenic changes of the atmosphere and land surface. This multi-timescale climatic evolution modulates the ``odds'' for local precipitation and soil moisture events, and hence for floods. An outstanding scientific challenge is to develop predictive probabilistic climate information of flood likelihood across these time scales, and to determine in which regions/basins or time-windows of opportunity such information may be of potential practical value. Using the Midwest of the United States as a case study, we present an analysis of daily circulation regimes derived from reanalysis wind data using a K-means cluster analysis for the March--May season, from which we infer relationships between flooding events and circulation regimes, as well as relationships between these regimes and climate variations throughout the 20th century on interdecadal, interannual, as well as intraseasonal timescales. The results of this work illustrate how typical and recurrent synoptic daily circulation patterns that drive enhanced southerly fluxes of moisture from the Gulf of Mexico are preferentially associated with extreme floods over the U.S. Midwest during the spring season, and how these same geopotential height patterns tend to occur more frequently during the La Niña phase of ENSO and certain phases of the MJO. The seasonality of flood occurrence as a function of latitude and longitude within the Midwest is tied to the seasonality

  15. The Response of Different Audiences to Place-based Communication about the Role of Climate Change in Extreme Weather Events

    NASA Astrophysics Data System (ADS)

    Halperin, A.; Walton, P.

    2015-12-01

    As the science of extreme event attribution grows, there is an increasing need to understand how the public responds to this type of climate change communication. Extreme event attribution has the unprecedented potential to locate the effects of climate change in the here and now, but there is little information about how different facets of the public might respond to these local framings of climate change. Drawing on theories of place attachment and psychological distance, this paper explores how people with different beliefs and values shift their willingness to mitigate and adapt to climate change in response to local or global communication of climate change impacts. Results will be presented from a recent survey of over 600 Californians who were each presented with one of three experimental conditions: 1) a local framing of the role of climate change in the California drought 2) a global framing of climate change and droughts worldwide, or 3) a control condition of no text. Participants were categorized into groups based on their prior beliefs about climate change according to the Six Americas classification scheme (Leiserowitz et al., 2011). The results from the survey in conjunction with qualitative results from follow-up interviews shed insight into the importance of place in communicating climate change for people in each of the Six Americas. Additional results examine the role of gender and political affiliation in mediating responses to climate change communication. Despite research that advocates unequivocally for local framing of climate change, this study offers a more nuanced perspective of under which circumstances extreme event attribution might be an effective tool for changing behaviors. These results could be useful for scientists who wish to gain a better understanding of how their event attribution research is perceived or for educators who want to target their message to audiences where it could have the most impact.

  16. Predicted climate change alters the indirect effect of predators on an ecosystem process.

    PubMed

    Lensing, Janet R; Wise, David H

    2006-10-17

    Changes in rainfall predicted to occur with global climate change will likely alter rates of leaf-litter decomposition through direct effects on primary decomposers. In a field experiment replicated at two sites, we show that altered rainfall may also change how cascading trophic interactions initiated by arthropod predators in the leaf litter indirectly influence litter decomposition. On the drier site there was no interaction between rainfall and the indirect effect of predators on decomposition. In contrast, on the moister site spiders accelerated the disappearance rate of deciduous leaf litter under low rainfall, but had no, or possibly a negative, indirect effect under high rainfall. Thus, changes resulting from the more intense hydrological cycle expected to occur with climate change will likely influence how predators indirectly affect an essential ecosystem process. PMID:17023538

  17. Generating extreme weather event sets from very large ensembles of regional climate models

    NASA Astrophysics Data System (ADS)

    Massey, Neil; Guillod, Benoit; Otto, Friederike; Allen, Myles; Jones, Richard; Hall, Jim

    2015-04-01

    Generating extreme weather event sets from very large ensembles of regional climate models Neil Massey, Benoit P. Guillod, Friederike E. L. Otto, Myles R. Allen, Richard Jones, Jim W. Hall Environmental Change Institute, University of Oxford, Oxford, UK Extreme events can have large impacts on societies and are therefore being increasingly studied. In particular, climate change is expected to impact the frequency and intensity of these events. However, a major limitation when investigating extreme weather events is that, by definition, only few events are present in observations. A way to overcome this issue it to use large ensembles of model simulations. Using the volunteer distributed computing (VDC) infrastructure of weather@home [1], we run a very large number (10'000s) of RCM simulations over the European domain at a resolution of 25km, with an improved land-surface scheme, nested within a free-running GCM. Using VDC allows many thousands of climate model runs to be computed. Using observations for the GCM boundary forcings we can run historical "hindcast" simulations over the past 100 to 150 years. This allows us, due to the chaotic variability of the atmosphere, to ascertain how likely an extreme event was, given the boundary forcings, and to derive synthetic event sets. The events in these sets did not actually occur in the observed record but could have occurred given the boundary forcings, with an associated probability. The event sets contain time-series of fields of meteorological variables that allow impact modellers to assess the loss the event would incur. Projections of events into the future are achieved by modelling projections of the sea-surface temperature (SST) and sea-ice boundary forcings, by combining the variability of the SST in the observed record with a range of warming signals derived from the varying responses of SSTs in the CMIP5 ensemble to elevated greenhouse gas (GHG) emissions in three RCP scenarios. Simulating the future with a

  18. Changes in large-scale climate alter spatial synchrony of aphid pests

    NASA Astrophysics Data System (ADS)

    Sheppard, Lawrence W.; Bell, James R.; Harrington, Richard; Reuman, Daniel C.

    2016-06-01

    Spatial synchrony, the tendency of distant populations to fluctuate similarly, is a major concern in ecology. Except in special circumstances, researchers historically had difficulty identifying drivers of synchrony in field systems. Perhaps for this reason, the possibility that changes in large-scale climatic drivers may modify synchrony, thereby impacting ecosystems and human concerns, has been little examined. Here, we use wavelets to determine environmental drivers of phenological synchrony across Britain for 20 aphid species, most major crop pests. Consistently across species, changes in drivers produced large changes in aphid synchrony. Different drivers acted on different timescales: using a new wavelet analogue of the Moran theorem, we show that on long timescales (>4 years), 80% of synchrony in aphid first flights is due to synchrony in winter climate; but this explanation accounts for less short-timescale (<=4 years) synchrony. Changes in aphid synchrony over time also differed by timescale: long-timescale synchrony fell from before 1993 to after, caused by similar changes in winter climate; whereas short-timescale synchrony increased. Shifts in winter climate are attributable to the North Atlantic Oscillation, an important climatic phenomenon, so effects described here may influence other taxa. This study documents a new way that climatic changes influence populations, through altered Moran effects.

  19. Stationary Wave Interference and its Relation to Tropical Convection and Climate Extremes

    NASA Astrophysics Data System (ADS)

    Feldstein, S. B.; Goss, M.; Lee, S.

    2015-12-01

    The impact of interference between transient eddies and the climatological stationary eddies is examined with ERA-Interim Reanalysis data. Composite calculations show that constructive interference during winter occurs about one week after enhanced Warm Pool convection, and is followed by the excitation of the positive phase of the Pacific/North American teleconnection pattern, an increase in surface air temperature over much of the extratropical Northern Hemisphere, along with a reduction of sea ice in the Barents and Kara Seas, a deceleration of the stratospheric polar vortex, and the excitation of the negative phase of the Arctic Oscillation. This surface warming does occur without prior Warm Pool convection, but it is enhanced and prolonged when constructive interference occurs in concert with the convection. This suggests that climate extremes may be more likely to occur when particular processes, such as Warm Pool convection and constructive interference, occur together. Opposite features are observed when there is destructive interference. To further investigate the influence of tropical convection, a series of idealized multi-level primitive equation model calculations is performed. The model's heating profiles are determined from composite CMAP precipitation anomalies for La Niña and El Niño months, and for MJO phase 1 and phase 5. As in the atmosphere, the model calculations find extratropical 300-hPa geopotential height anomalies of opposite sign for MJO phase 1 and El Nino heating, even though the heating profiles closely resemble each other. (Analogous results were found for MJO phase 5 and La Nina.) The model was also run with individual heating anomalies in key geographic locations. The results suggest that the extratropical response to both ENSO and MJO convective heating anomalies can be understood as arising from the competing influences of Warm Pool and central Pacific tropical convection. These results allude to the possibility that the

  20. Impact of past and future climate variability and extreme events on carbon loss in European arable agriculture

    NASA Astrophysics Data System (ADS)

    Balkovic, Juraj; van der Velde, Marijn; Khabarov, Nikolay; Beer, Christian

    2013-04-01

    Predictions of climate models suggest an increase in climate variability and an increased probability in the occurrence of extreme weather events during this century. The expected increase in variability of meteorological variables such as temperature and precipitation will impact the productive functions as well as the ecosystem services agricultural systems provide, including the storage of soil organic carbon. Here we use a methodology and specifically tailored climate datasets that were developed in the EU FP7 CARBO-Extreme project to analyze the effect of increased climate variability on long term soil organic carbon sequestration, erosion and crop production in Europe. We quantified the changing impact of extreme events on carbon dynamics and soil organic carbon loss from agricultural soil cultivated with wheat, barley, maize and rye in Europe for the period from 1900-2100. In separate simulations we specifically address the potential losses of soil carbon associated with erosion. We further characterized the effect of CO2 fertilization on crop growth. Preliminary results indicate a growing contribution of extreme weather generally lowering biomass production and crop yields in Europe, albeit with regional variations. This decrease will lead to a relatively lower input of organic matter into the soil and generally lower soil organic carbon stocks. Yet, in areas characterized by relatively drier conditions the decomposition of organic material and thus heterotrophic transpiration is reduced which can result in a net accumulation of soil organic matter. Finally, we attempted to identify the cropland area susceptible to increased carbon loss due to climate extremes by unraveling the relative contribution of the combined spatial fingerprint of physiographic characteristics and climate extremes over Europe.

  1. Agroclimatic potential in central Siberia in an altered 21st century climate

    NASA Astrophysics Data System (ADS)

    Soja, A.; Tchebakova, N.; Parfenova, E.; Lysanova, G.

    2012-04-01

    The largest temperature increases are currently found in Northern Hemishpere upper latitudes, and this is where temperature increases from climate change are predicted to be the greatest in the future. Alteration of boreal and Arctic landscapes is already apparent, particularly in Siberia. In this work, we will explore the current spatial and temporal patterns of agriculture potential in Siberia and then investigate potential future agriculture dynamics. Humans have traditionally cultivated steppe and forest-steppe on fertile soils for agriculture. It is predicted that forests will move northwards in a warmer climate and be replaced by forest-steppe and steppe ecosystems. Climate change impacts on agriculture in south-central Siberia are analyzed based on the hypothesis that agriculture in traditionally cold Siberia may benefit from warming. Simple models are used to determine crop range and regression models are constructed to determine crop yield, and these are applied to climate change scenarios for various time frames: pre-1960, 1960-1990, 1990-2010 using historic data and for 2020 and 2080 using HadCM3 B1 and A2 projections. From 50 to 85% of central Siberia is predicted to be climatically suitable for agriculture by the end of the century, and only soil potential would limit crop advance and expansion to the north. Crop production could increase twofold. Future climatic resources in Siberia would provide potential growth for a variety of crops that previously did not exist on these lands. Traditional Siberian crops could gradually shift as far as 500 km northwards (about 50-70 km per decade) within suitable soil conditions, and new crops, nonexistent today, may be introduced in the dry south that would necessitate irrigation. Agriculture in central Siberia would likely benefit from climate warming but would also result in different feedbacks to the atmosphere and climate systems, in terms of an altered landscape albedo, substantially modified hydrological

  2. What Can The Engineering for Climate Extremes Partnership Do For Global Resilience?

    NASA Astrophysics Data System (ADS)

    Bruyere, C. L.; Tye, M. R.; Holland, G. J.

    2015-12-01

    ECEP is an interdisciplinary partnership that brings together academia, industry, commerce, societal groups and government to develop robust, well-communicated predictions and advice on the impacts of weather and climate extremes using cutting-edge science. A feature of the partnership is the manner in which basic and applied research and development is conducted in direct collaboration with the end user. ECEP was formally launched at the AGU Fall Meeting in December 2014, and has gained rapid momentum in the subsequent year. Integral to the ECEP approach to resilience is the concept of 'Graceful Failure'. By acknowledging that all designs will fail at some level, and instead adopting flexible designs that combine engineering or network strengths with a plan for efficient, systematic failure and avoid delayed recovery. Such an approach enables optimal planning for both known and future scenarios, and their assessed uncertainty. This presentation will use the Boulder and North Colorado floods of September 2013 as a case study of how Graceful Failure improves resilience to extreme weather.

  3. Alpine climate alters the relationships between leaf and root morphological traits but not chemical traits.

    PubMed

    Geng, Yan; Wang, Liang; Jin, Dongmei; Liu, Huiying; He, Jin-Sheng

    2014-06-01

    Leaves and fine roots are among the most important and dynamic components of terrestrial ecosystems. To what extent plants synchronize their resource capture strategies above- and belowground remains uncertain. Existing results of trait relationships between leaf and root showed great inconsistency, which may be partly due to the differences in abiotic environmental conditions such as climate and soil. Moreover, there is currently little evidence on whether and how the stringent environments of high-altitude alpine ecosystems alter the coordination between above- and belowground. Here we measured six sets of analogous traits for both leaves and fine roots of 139 species collected from Tibetan alpine grassland and Mongolian temperate grassland. N, P and N:P ratio of leaves and fine roots were positively correlated, independent of biogeographic regions, phylogenetic affiliation or climate. In contrast, leaves and fine roots seem to regulate morphological traits more independently. The specific leaf area (SLA)-specific root length (SRL) correlation shifted from negative at sites under low temperature to positive at warmer sites. The cold climate of alpine regions may impose different constraints on shoots and roots, selecting simultaneously for high SLA leaves for rapid C assimilation during the short growing season, but low SRL roots with high physical robustness to withstand soil freezing. In addition, there might be more community heterogeneity in cold soils, resulting in multidirectional strategies of root in resource acquisition. Thus our results demonstrated that alpine climate alters the relationships between leaf and root morphological but not chemical traits.

  4. Assessment of climate change impact on hydrological extremes in two source regions of the Nile River Basin

    NASA Astrophysics Data System (ADS)

    Taye, M. T.; Ntegeka, V.; Ogiramoi, N. P.; Willems, P.

    2011-01-01

    The potential impact of climate change was investigated on the hydrological extremes of Nyando River and Lake Tana catchments, which are located in two source regions of the Nile River basin. Climate change scenarios were developed for rainfall and potential evapotranspiration (ETo), considering 17 General Circulation Model (GCM) simulations to better understand the range of possible future change. They were constructed by transferring the extracted climate change signals to the observed series using a frequency perturbation downscaling approach, which accounts for the changes in rainfall extremes. Projected changes under two future SRES emission scenarios A1B and B1 for the 2050s were considered. Two conceptual hydrological models were calibrated and used for the impact assessment. Their difference in simulating the flows under future climate scenarios was also investigated. The results reveal increasing mean runoff and extreme peak flows for Nyando catchment for the 2050s while unclear trend is observed for Lake Tana catchment for mean volumes and high/low flows. The hydrological models for Lake Tana catchment, however, performed better in simulating the hydrological regimes than for Nyando, which obviously also induces a difference in the reliability of the extreme future projections for both catchments. The unclear impact result for Lake Tana catchment implies that the GCM uncertainty is more important for explaining the unclear trend than the hydrological models uncertainty. Nevertheless, to have a better understanding of future impact, hydrological models need to be verified for their credibility of simulating extreme flows.

  5. Future hydrological extremes: the uncertainty from multiple global climate and global hydrological models

    NASA Astrophysics Data System (ADS)

    Giuntoli, I.; Vidal, J.-P.; Prudhomme, C.; Hannah, D. M.

    2015-05-01

    Projections of changes in the hydrological cycle from global hydrological models (GHMs) driven by global climate models (GCMs) are critical for understanding future occurrence of hydrological extremes. However, uncertainties remain large and need to be better assessed. In particular, recent studies have pointed to a considerable contribution of GHMs that can equal or outweigh the contribution of GCMs to uncertainty in hydrological projections. Using six GHMs and five GCMs from the ISI-MIP multi-model ensemble, this study aims: (i) to assess future changes in the frequency of both high and low flows at the global scale using control and future (RCP8.5) simulations by the 2080s, and (ii) to quantify, for both ends of the runoff spectrum, GCMs and GHMs contributions to uncertainty using a two-way ANOVA. Increases are found in high flows for northern latitudes and in low flows for several hotspots. Globally, the largest source of uncertainty is associated with GCMs, but GHMs are the greatest source in snow-dominated regions. More specifically, results vary depending on the runoff metric, the temporal (annual and seasonal) and regional scale of analysis. For instance, uncertainty contribution from GHMs is higher for low flows than it is for high flows, partly owing to the different processes driving the onset of the two phenomena (e.g. the more direct effect of the GCMs' precipitation variability on high flows). This study provides a comprehensive synthesis of where future hydrological extremes are projected to increase and where the ensemble spread is owed to either GCMs or GHMs. Finally, our results underline the need for improvements in modelling snowmelt and runoff processes to project future hydrological extremes and the importance of using multiple GCMs and GHMs to encompass the uncertainty range provided by these two sources.

  6. The impact of an extreme case of irrigation on the southeastern United States climate

    NASA Astrophysics Data System (ADS)

    Selman, Christopher; Misra, Vasubandhu

    2016-05-01

    The impacts of irrigation on southeast United States diurnal climate are investigated using simulations from a regional climate model. An extreme case is assumed, wherein irrigation is set to 100 % of field capacity over the growing season of May through October. Irrigation is applied to the root zone layers of 10-40 and 40-100 cm soil layers only. It is found that in this regime there is a pronounced decrease in monthly averaged temperatures in irrigated regions across all months. In non-irrigated areas a slight warming is simulated. Diurnal maximum temperatures in irrigated areas warm, while diurnal minimum temperatures cool. The daytime warming is attributed to an increase in shortwave flux at the surface owing to diminished low cloud cover. Nighttime and daily mean cooling result as a consequence repartitioning of energy into latent heat flux over sensible heat flux, and of a higher net downward ground heat flux. Excess heat is transported into the deep soil layer, preventing a rapidly intensifying positive feedback loop. Both diurnal and monthly average precipitations are reduced over irrigated areas at a magnitude and spatial pattern similar to one another. Due to the excess moisture availability, evaporation is seen to increase, but this is nearly balanced by a corresponding reduction in sensible heat flux. Concomitant with additional moisture availability is an increase in both transient and stationary moisture flux convergences. However, despite the increase, there is a large-scale stabilization of the atmosphere stemming from a cooled surface.

  7. Climate change alters plant biogeography in Mediterranean prairies along the West Coast, USA.

    PubMed

    Pfeifer-Meister, Laurel; Bridgham, Scott D; Reynolds, Lorien L; Goklany, Maya E; Wilson, Hannah E; Little, Chelsea J; Ferguson, Aryana; Johnson, Bart R

    2016-02-01

    Projected changes in climate are expected to have widespread effects on plant community composition and diversity in coming decades. However, multisite, multifactor climate manipulation studies that have examined whether observed responses are regionally consistent and whether multiple climate perturbations are interdependent are rare. Using such an experiment, we quantified how warming and increased precipitation intensity affect the relative dominance of plant functional groups and diversity across a broad climate gradient of Mediterranean prairies. We implemented a fully factorial climate manipulation of warming (+2.5-3.0 °C) and increased wet-season precipitation (+20%) at three sites across a 520-km latitudinal gradient in the Pacific Northwest, USA. After seeding with a nearly identical mix of native species at all sites, we measured plant community composition (i.e., cover, richness, and diversity), temperature, and soil moisture for 3 years. Warming and the resultant drying of soils altered plant community composition, decreased native diversity, and increased total cover, with warmed northern communities becoming more similar to communities further south. In particular, after two full years of warming, annual cover increased and forb cover decreased at all sites mirroring the natural biogeographic pattern. This suggests that the extant climate gradient of increasing heat and drought severity is responsible for a large part of the observed biogeographic pattern of increasing annual invasion in US West Coast prairies as one moves further south. Additional precipitation during the rainy season did little to relieve drought stress and had minimal effects on plant community composition. Our results suggest that the projected increase in drought severity (i.e., hotter, drier summers) in Pacific Northwest prairies may lead to increased invasion by annuals and a loss of forbs, similar to what has been observed in central and southern California, resulting in

  8. Characterizing phenological vegetation dynamics amidst extreme climate variability in Australia with MODIS VI data

    NASA Astrophysics Data System (ADS)

    Broich, M.; Huete, A. R.; Xuanlon, M.; Davies, K.; Restrepo-Coupe, N.; Ratana, P.

    2012-12-01

    Australia's climate is extremely variable with inter-annual rainfall at any given site varying by 5- or 6-fold or more, across the continent. In addition to such inter-annual variability, there can be significant intra-annual variability, especially in monsoonal Australia (e.g. the wet tropical savannas) and Mediterranean climates in SW Australia where prolonged dry seasons occur each year. This presents unique challenges to the characterization of seasonal dynamics with satellite datasets. In contrast to annual reoccurring temperature-driven phenology of northern hemisphere mid-latitudes, vegetation dynamics of the vast and dry Australian interior are poorly quantified by existing remote sensing products. For example, in the current global-based MODIS phenology product, central Australia is covered by ~30% fill values for any given year. Two challenges are specific to Australian landscapes: first, the difficulty of characterizing seasonality of rainfall-driven ecosystems in interior Australia where duration and magnitude of green-up and brown down cycles show high inter annual variability; second, modeling two phenologic layers, the trees and the grass in savannas were the trees are evergreen but the herbaceous understory varies with rainfall. Savannas cover >50% of Australia. Australia's vegetation and climate are different from other continents. A MODIS phenology product capable of characterizing vegetation dynamics across the continent is being developed in this research as part of the AusCover national expert network aiming to provide Australian biophysical remote sensing data time-series and continental-scale map products. These products aim to support the Terrestrial Ecosystem Research Network (TERN) serving ecosystem research in Australia. The MODIS land surface product for Australia first searches the entire time series of each Climate Modeling Grid pixel for low-high-low extreme point sequences. A double logistic function is then fit to each of these

  9. Influence of altered low cloud parameterizations for seasonal variation of Arctic cloud amount on climate feedbacks

    NASA Astrophysics Data System (ADS)

    Kim, Yoojin; Choi, Yong-Sang; Kim, Baek-Min; Kim, Hyerim

    2015-12-01

    This study investigates the alteration of climate feedbacks due to overestimated wintertime low-level cloud amount bias over the Arctic region (60°N-90°N) in a climate model. The climate feedback was quantitatively examined through radiative kernels that are pre-calculated radiative responses of climate variables to doubling of carbon dioxide concentration in NCAR Community Atmosphere Model version 3 (CAM3). Climate models have various annual cycle of the Arctic cloud amount at the low-level particularly with large uncertainty in winter and CAM3 may tend to overestimate the Arctic low-level cloud. In this study, the seasonal variation of low-level cloud amount was modified by reducing the wintertime cloud amount by up to 35 %, and then compared with the original without seasonal variation. Thus, we investigate how that bias may affect climate feedbacks and the projections of future Arctic warming. The results show that the decrease in low-level cloud amount slightly affected the radiation budgets because of a small amount of incident solar insolation in winter, but considerably changed water vapor and temperature profiles. Consequently, the most distinctive was decreases in water vapor feedback and contribution of heat transport (by -0.20 and -0.55 W m-2 K-1, respectively) and increases in the lapse rate feedback and cloud feedback (by 0.13 and 0.58 W m-2 K-1, respectively) during winter in this model experiment. This study suggests that the change in Arctic cloud amount effectively reforms the contributions of individual climate feedbacks to Arctic climate system and leads to opposing effects on different feedbacks, which cancel out in the model.

  10. Influence of altered low cloud parameterizations for seasonal variation of Arctic cloud amount on climate feedbacks

    NASA Astrophysics Data System (ADS)

    Kim, Yoojin; Choi, Yong-Sang; Kim, Baek-Min; Kim, Hyerim

    2016-09-01

    This study investigates the alteration of climate feedbacks due to overestimated wintertime low-level cloud amount bias over the Arctic region (60°N-90°N) in a climate model. The climate feedback was quantitatively examined through radiative kernels that are pre-calculated radiative responses of climate variables to doubling of carbon dioxide concentration in NCAR Community Atmosphere Model version 3 (CAM3). Climate models have various annual cycle of the Arctic cloud amount at the low-level particularly with large uncertainty in winter and CAM3 may tend to overestimate the Arctic low-level cloud. In this study, the seasonal variation of low-level cloud amount was modified by reducing the wintertime cloud amount by up to 35 %, and then compared with the original without seasonal variation. Thus, we investigate how that bias may affect climate feedbacks and the projections of future Arctic warming. The results show that the decrease in low-level cloud amount slightly affected the radiation budgets because of a small amount of incident solar insolation in winter, but considerably changed water vapor and temperature profiles. Consequently, the most distinctive was decreases in water vapor feedback and contribution of heat transport (by -0.20 and -0.55 W m-2 K-1, respectively) and increases in the lapse rate feedback and cloud feedback (by 0.13 and 0.58 W m-2 K-1, respectively) during winter in this model experiment. This study suggests that the change in Arctic cloud amount effectively reforms the contributions of individual climate feedbacks to Arctic climate system and leads to opposing effects on different feedbacks, which cancel out in the model.

  11. Study of Extreme Hydrometeorological Events under Consideration of Climate Change in terms of Flood Protection Design Standard

    NASA Astrophysics Data System (ADS)

    Lin, B.-Z.

    2012-04-01

    common frequencies to rare frequencies. Probable Maximum Precipitation (PMP) is defined as the greatest depth of precipitation for a given duration meteorologically possible for a design watershed or a given storm area at a particular location at a particular time of year, with no allowance made for long-term climate trends (WMO, 2009). The PMP has been widely used by many hydrologists to determine the probable maximum flood (PMF) critical to the design of a variety of hydrological structures and other high profile infrastructures such as nuclear power-generation station with respect to flood-protection, for which a high level safety is required. What is the impact of climate change on PMP estimation? Actually, in the definition of PMP, there is "no allowance made for long-term climate trends" (WMO, 2009). However, when people are talking about impact of climate change on PMP estimation, two things may be taken into account practically: (1) To affect the precipitable water as a result of increase of SST; (2) Effect on the selection of the transposed storm because more extreme storms would occur due to climate change and more potential candidates to be used for storm transposition. The occurrence of a severe rainfall storm could alter the PMP estimates. A good example is the lashing of the Typhoon Morakot of 8 - 10 Aug. 2009 on Taiwan Island that set up new rainfall picture. What is the effect of topography on rainfall is another big issue in PMP estimation. Many observations of precipitation in mountainous areas show a general increase in precipitation with elevation. Practically, the effect of topography on rainfall should be taken into account in PMP estimation and implemented by the storm separation technique. The Step-Duration-Orographic-Intensification-Factor (SDOIF) Method, which was developed based on statistics analysis of extreme rainfalls in the storm area, can practically be used as storm separation technique to decouple the Morakot storm rainfalls into two

  12. A spatial assessment framework for evaluating flood risk under extreme climates.

    PubMed

    Chen, Yun; Liu, Rui; Barrett, Damian; Gao, Lei; Zhou, Mingwei; Renzullo, Luigi; Emelyanova, Irina

    2015-12-15

    Australian coal mines have been facing a major challenge of increasing risk of flooding caused by intensive rainfall events in recent years. In light of growing climate change concerns and the predicted escalation of flooding, estimating flood inundation risk becomes essential for understanding sustainable mine water management in the Australian mining sector. This research develops a spatial multi-criteria decision making prototype for the evaluation of flooding risk at a regional scale using the Bowen Basin and its surroundings in Queensland as a case study. Spatial gridded data, including climate, hydrology, topography, vegetation and soils, were collected and processed in ArcGIS. Several indices were derived based on time series of observations and spatial modeling taking account of extreme rainfall, evapotranspiration, stream flow, potential soil water retention, elevation and slope generated from a digital elevation model (DEM), as well as drainage density and proximity extracted from a river network. These spatial indices were weighted using the analytical hierarchy process (AHP) and integrated in an AHP-based suitability assessment (AHP-SA) model under the spatial risk evaluation framework. A regional flooding risk map was delineated to represent likely impacts of criterion indices at different risk levels, which was verified using the maximum inundation extent detectable by a time series of remote sensing imagery. The result provides baseline information to help Bowen Basin coal mines identify and assess flooding risk when making adaptation strategies and implementing mitigation measures in future. The framework and methodology developed in this research offers the Australian mining industry, and social and environmental studies around the world, an effective way to produce reliable assessment on flood risk for managing uncertainty in water availability under climate change.

  13. Food Prices and Climate Extremes: A Model of Global Grain Price Variability with Storage

    NASA Astrophysics Data System (ADS)

    Otto, C.; Schewe, J.; Frieler, K.

    2015-12-01

    Extreme climate events such as droughts, floods, or heat waves affect agricultural production in major cropping regions and therefore impact the world market prices of staple crops. In the last decade, crop prices exhibited two very prominent price peaks in 2007-2008 and 2010-2011, threatening food security especially for poorer countries that are net importers of grain. There is evidence that these spikes in grain prices were at least partly triggered by actual supply shortages and the expectation of bad harvests. However, the response of the market to supply shocks is nonlinear and depends on complex and interlinked processes such as warehousing, speculation, and trade policies. Quantifying the contributions of such different factors to short-term price variability remains difficult, not least because many existing models ignore the role of storage which becomes important on short timescales. This in turn impedes the assessment of future climate change impacts on food prices. Here, we present a simple model of annual world grain prices that integrates grain stocks into the supply and demand functions. This firstly allows us to model explicitly the effect of storage strategies on world market price, and thus, for the first time, to quantify the potential contribution of trade policies to price variability in a simple global framework. Driven only by reported production and by long--term demand trends of the past ca. 40 years, the model reproduces observed variations in both the global storage volume and price of wheat. We demonstrate how recent price peaks can be reproduced by accounting for documented changes in storage strategies and trade policies, contrasting and complementing previous explanations based on different mechanisms such as speculation. Secondly, we show how the integration of storage allows long-term projections of grain price variability under climate change, based on existing crop yield scenarios.

  14. A spatial assessment framework for evaluating flood risk under extreme climates.

    PubMed

    Chen, Yun; Liu, Rui; Barrett, Damian; Gao, Lei; Zhou, Mingwei; Renzullo, Luigi; Emelyanova, Irina

    2015-12-15

    Australian coal mines have been facing a major challenge of increasing risk of flooding caused by intensive rainfall events in recent years. In light of growing climate change concerns and the predicted escalation of flooding, estimating flood inundation risk becomes essential for understanding sustainable mine water management in the Australian mining sector. This research develops a spatial multi-criteria decision making prototype for the evaluation of flooding risk at a regional scale using the Bowen Basin and its surroundings in Queensland as a case study. Spatial gridded data, including climate, hydrology, topography, vegetation and soils, were collected and processed in ArcGIS. Several indices were derived based on time series of observations and spatial modeling taking account of extreme rainfall, evapotranspiration, stream flow, potential soil water retention, elevation and slope generated from a digital elevation model (DEM), as well as drainage density and proximity extracted from a river network. These spatial indices were weighted using the analytical hierarchy process (AHP) and integrated in an AHP-based suitability assessment (AHP-SA) model under the spatial risk evaluation framework. A regional flooding risk map was delineated to represent likely impacts of criterion indices at different risk levels, which was verified using the maximum inundation extent detectable by a time series of remote sensing imagery. The result provides baseline information to help Bowen Basin coal mines identify and assess flooding risk when making adaptation strategies and implementing mitigation measures in future. The framework and methodology developed in this research offers the Australian mining industry, and social and environmental studies around the world, an effective way to produce reliable assessment on flood risk for managing uncertainty in water availability under climate change. PMID:26318687

  15. Recovery dynamics and invasibility of herbaceous plant communities after exposure to fifty-year climate extremes in different seasons

    NASA Astrophysics Data System (ADS)

    Dreesen, F. E.; De Boeck, H. J.; Janssens, I. A.; Nijs, I.

    2013-10-01

    Disturbance events such as climatic extremes may enhance the invasibility of plant communities, through the creation of gaps and the associated local increase in available resources. In this study, experimental herbaceous communities consisting of three species were subjected to 50 yr extreme drought and/or heat events, in spring, summer or autumn. In the year of the induced extremes, species mortality and end-of-season biomass were examined. In two subsequent years without further disturbances, establishment of new species was recorded. The drought and drought + heat extremes in summer and autumn induced greater plant mortality compared with the heat extremes in those seasons and compared with all extremes applied in spring, in all three originally planted species. Recovery in terms of biomass towards the end of the growing season, however, was species-specific. The dominant species, the nitrogen fixer Trifolium repens, recovered poorly from the drought and drought + heat extremes which governed the community response. Community biomass, which was heavily affected by the drought and especially by the drought + heat events in summer and autumn, reached control values already one year later. Invasibility was increased in the communities that underwent the drought + heat extremes in the first year following the extreme events, but no longer in the second year. During the two years of invasion, the community composition changed, but independently of the type and impact of the extreme event. In short, the extreme climate events greatly affected the survival and productivity of the species, modified the species composition and dominance patterns, and increased the invasibility of our plant communities. However, none of these community properties seemed to be affected in the long term, as the induced responses faded out after one or two years.

  16. Wearing a Wetsuit Alters Upper Extremity Motion during Simulated Surfboard Paddling

    PubMed Central

    Nessler, J. A.; Silvas, M.; Carpenter, S.; Newcomer, S. C.

    2015-01-01

    Surfers often wear wetsuits while paddling in the ocean. This neoprene covering may be beneficial to upper extremity movement by helping to improve proprioceptive acuity, or it may be detrimental by providing increased resistance. The purpose of this study was to evaluate the effects of wearing a wetsuit on muscle activation, upper extremity motion, heart rate, and oxygen consumption during simulated surfboard paddling in the laboratory. Twelve male, recreational surfers performed two paddling trials at a constant workload on a swim bench ergometer both with and without a wetsuit. Kinematic data and EMG were acquired from the right arm via motion capture, and oxygen consumption and heart rate were recorded with a metabolic cart and heart rate monitor. Wearing a wetsuit had no significant effect on oxygen consumption or heart rate. A significant increase in EMG activation was observed for the middle deltoid but not for any of the other shoulder muscle evaluated. Finally, approximate entropy and estimates of the maximum Lyapunov exponent increased significantly for vertical trajectory of the right wrist (i.e. stroke height) when a wetsuit was worn. These results suggest that a 2mm wetsuit has little effect on the energy cost of paddling at lower workloads but does affect arm motion. These changes may be the result of enhanced proprioceptive acuity due to mechanical compression from the wetsuit. PMID:26551321

  17. Climate Change: A New Metric to Measure Changes in the Frequency of Extreme Temperatures using Record Data

    NASA Technical Reports Server (NTRS)

    Munasinghe, L.; Jun, T.; Rind, D. H.

    2012-01-01

    Consensus on global warming is the result of multiple and varying lines of evidence, and one key ramification is the increase in frequency of extreme climate events including record high temperatures. Here we develop a metric- called "record equivalent draws" (RED)-based on record high (low) temperature observations, and show that changes in RED approximate changes in the likelihood of extreme high (low) temperatures. Since we also show that this metric is independent of the specifics of the underlying temperature distributions, RED estimates can be aggregated across different climates to provide a genuinely global assessment of climate change. Using data on monthly average temperatures across the global landmass we find that the frequency of extreme high temperatures increased 10-fold between the first three decades of the last century (1900-1929) and the most recent decade (1999-2008). A more disaggregated analysis shows that the increase in frequency of extreme high temperatures is greater in the tropics than in higher latitudes, a pattern that is not indicated by changes in mean temperature. Our RED estimates also suggest concurrent increases in the frequency of both extreme high and extreme low temperatures during 2002-2008, a period when we observe a plateauing of global mean temperature. Using daily extreme temperature observations, we find that the frequency of extreme high temperatures is greater in the daily minimum temperature time-series compared to the daily maximum temperature time-series. There is no such observable difference in the frequency of extreme low temperatures between the daily minimum and daily maximum.

  18. Impacts on cropping systems of present and future extreme events assessed with various regional climate models in the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Ruiz-Ramos, M.; Gallardo, C.; Sánchez, E.; Mínguez, M. I.

    2009-04-01

    Climate variability and extreme events in particular, are expected to increase with climate change. Several types of extreme processes, such as freezing, heat or cold waves, droughts or heavy precipitation situations are of special relevance for agricultural impacts. Not only the frequency and intensity of these events but also their timing compared to the crop development will determine their impact. Mediterranean agriculture has been reported to present important climate change impacts with related high uncertainty. In this work, crop simulation models of maize and wheat were applied in several agricultural locations of the Iberian Peninsula using climate data from a group of regional climate models (RCMs) participating in the European Project PRUDENCE. The objective was to analyze the effect of extreme events in agriculture in future climate (A2 IPCC SRES scenario for 2070-2100) in relation to current conditions (1960-1990). The use of several RCMs allows for one uncertainty evaluation associated to these processes. The analysis enabled identifying periods with maximum and minimum probability of risk related to crop development, and will help to design adaptation strategies in cropping systems to match minimum risk periods.

  19. Climatic and biotic extreme events moderate long-term responses of above- and belowground sub-Arctic heathland communities to climate change.

    PubMed

    Bokhorst, Stef; Phoenix, Gareth K; Berg, Matty P; Callaghan, Terry V; Kirby-Lambert, Christopher; Bjerke, Jarle W

    2015-11-01

    Climate change impacts are not uniform across the Arctic region because interacting factors causes large variations in local ecosystem change. Extreme climatic events and population cycles of herbivores occur simultaneously against a background of gradual climate warming trends and can redirect ecosystem change along routes that are difficult to predict. Here, we present the results from sub-Arctic heath vegetation and its belowground micro-arthropod community in response to the two main drivers of vegetation damage in this region: extreme winter warming events and subsequent outbreaks of the defoliating autumnal moth caterpillar (Epirrita autumnata). Evergreen dwarf shrub biomass decreased (30%) following extreme winter warming events and again by moth caterpillar grazing. Deciduous shrubs that were previously exposed to an extreme winter warming event were not affected by the moth caterpillar grazing, while those that were not exposed to warming events (control plots) showed reduced (23%) biomass from grazing. Cryptogam cover increased irrespective of grazing or winter warming events. Micro-arthropods declined (46%) following winter warming but did not respond to changes in plant community. Extreme winter warming and caterpillar grazing suppressed the CO2 fluxes of the ecosystem. Evergreen dwarf shrubs are disadvantaged in a future sub-Arctic with more stochastic climatic and biotic events. Given that summer warming may further benefit deciduous over evergreen shrubs, event and trend climate change may both act against evergreen shrubs and the ecosystem functions they provide. This is of particular concern given that Arctic heath vegetation is typically dominated by evergreen shrubs. Other components of the vegetation showed variable responses to abiotic and biotic events, and their interaction indicates that sub-Arctic vegetation response to multiple pressures is not easy to predict from single-factor responses. Therefore, while biotic and climatic events may

  20. Climatic and biotic extreme events moderate long-term responses of above- and belowground sub-Arctic heathland communities to climate change.

    PubMed

    Bokhorst, Stef; Phoenix, Gareth K; Berg, Matty P; Callaghan, Terry V; Kirby-Lambert, Christopher; Bjerke, Jarle W

    2015-11-01

    Climate change impacts are not uniform across the Arctic region because interacting factors causes large variations in local ecosystem change. Extreme climatic events and population cycles of herbivores occur simultaneously against a background of gradual climate warming trends and can redirect ecosystem change along routes that are difficult to predict. Here, we present the results from sub-Arctic heath vegetation and its belowground micro-arthropod community in response to the two main drivers of vegetation damage in this region: extreme winter warming events and subsequent outbreaks of the defoliating autumnal moth caterpillar (Epirrita autumnata). Evergreen dwarf shrub biomass decreased (30%) following extreme winter warming events and again by moth caterpillar grazing. Deciduous shrubs that were previously exposed to an extreme winter warming event were not affected by the moth caterpillar grazing, while those that were not exposed to warming events (control plots) showed reduced (23%) biomass from grazing. Cryptogam cover increased irrespective of grazing or winter warming events. Micro-arthropods declined (46%) following winter warming but did not respond to changes in plant community. Extreme winter warming and caterpillar grazing suppressed the CO2 fluxes of the ecosystem. Evergreen dwarf shrubs are disadvantaged in a future sub-Arctic with more stochastic climatic and biotic events. Given that summer warming may further benefit deciduous over evergreen shrubs, event and trend climate change may both act against evergreen shrubs and the ecosystem functions they provide. This is of particular concern given that Arctic heath vegetation is typically dominated by evergreen shrubs. Other components of the vegetation showed variable responses to abiotic and biotic events, and their interaction indicates that sub-Arctic vegetation response to multiple pressures is not easy to predict from single-factor responses. Therefore, while biotic and climatic events may

  1. Species-specific fine root biomass distribution alters competition in mixed forests under climate change

    NASA Astrophysics Data System (ADS)

    Reyer, Christopher; Gutsch, Martin; Lasch, Petra; Suckow, Felicitas; Sterck, Frank; Mohren, Frits

    2010-05-01

    The importance of mixed forests in European silviculture has increased due to forest conversion policies and multifunctional forest management. Concurrently, evidences for substantial impacts of climate change on forest ecosystems accumulate. Projected drier and warmer conditions alter the water relations of tree species, their growth and ultimately their inter-specific competition in mixed stands. Process-based models are scientific tools to study the impact of climate change on and to deepen the understanding of the functioning of these systems based on ecological mechanisms. They allow for long-term, stand-level studies of forest dynamics which could only be addressed with great difficulty in an experimental or empirical setup. We used the process-based forest model 4C to simulate inter-specific competition in mixed stands of Douglas-fir (Pseudotsuga menziesii) and Common beech (Fagus sylvatica) as well as Scots pine (Pinus sylvestris) and Sessile / Pedunculate oak (Quercus petraea and Quercus robur) under a) historical climate for model verification and b) under climate change scenario realizations of the climate model STAR 2.0 in Brandenburg, Germany. Some of the climate change scenario realizations feature a substantially drier and warmer summer climate which decreases the climatic water balance during the growing season. We assumed species-specific fine root biomass distributions which feature broadleaved fine roots in deeper soil layers and coniferous fine roots in upper soil layers according to several root excavation studies from mixed stands. The stands themselves were constructed from yield tables of the contributing species. The model verification provided good results for the basal area predictions under the historical climate. Under climate change, the number of days when the tree water demand exceeded the soil water supply was higher for the coniferous species than for broadleaved species. Furthermore, after 45 simulation years the basal area

  2. Evidence for altered upper extremity muscle synergies in chronic stroke survivors with mild and moderate impairment

    PubMed Central

    Roh, Jinsook; Rymer, William Z.; Beer, Randall F.

    2015-01-01

    Previous studies indicate that motor coordination may be achieved by assembling task-dependent combinations of a few muscle synergies, defined here as fixed patterns of activation across a set of muscles. Our recent study of severely impaired chronic stroke survivors showed that some muscle synergies underlying isometric force generation at the hand are altered in the affected arm. However, whether similar alterations are evident in stroke survivors with lesser impairment remains unclear. Accordingly, we examined muscle synergies underlying spatial patterns of elbow and shoulder muscle activation recorded during an isometric force target matching protocol performed by 16 chronic stroke survivors, evenly divided across mild and moderate impairment levels. We applied non-negative matrix factorization to identify the muscle synergies and compared their structure across groups, including previously collected data from six age-matched control subjects and eight severely impaired stroke survivors. For all groups, EMG spatial patterns were well explained by task-dependent combinations of only a few (typically 4) muscle synergies. Broadly speaking, elbow-related synergies were conserved across stroke survivors, regardless of impairment level. In contrast, the shoulder-related synergies of some stroke survivors with mild and moderate impairment differed from controls, in a manner similar to severely impaired subjects. Cluster analysis of pooled synergies for the 30 subjects identified seven distinct clusters (synergies). Subsequent analysis confirmed that the incidences of three elbow-related synergies were independent of impairment level, while the incidences of four shoulder-related synergies were systematically correlated with impairment level. Overall, our results suggest that alterations in the shoulder muscle synergies underlying isometric force generation appear prominently in mild and moderate stroke, as in most cases of severe stroke, in an impairment level

  3. Extraction and use of historical extreme climate databases for nuclear power plants safety assessment

    NASA Astrophysics Data System (ADS)

    Hamdi, Yasser; Bertin, Xavier; Bardet, Lise; Duluc, Claire-Marie; Rebour, Vincent

    2015-04-01

    Safety assessments of nuclear power plants (NPPs) related to natural hazards are a matter of major interest to the nuclear community in France and many European countries. Over the past fewer decades, France has experienced many of these events such as heat waves (2003 and 2006), heavy snowstorms (1958, 1990 and 1992), storms which have given rise to heavy rain and severe floods (1992, 1999, 2010), strong straight-line wind and extreme marine surges (1987, 1999 and 2010) much larger than the other local observations (outliers). These outliers had clearly illustrated the potential to underestimate the extreme surges calculated with the current statistical methods. The estimation of extreme surges then requires the use of a statistical analysis approach having a more solid theoretical framework and using more reliable databases for the assessment of hazards to design NPPs to low or extremely low probabilities of failure. These databases can be produced by collecting historical information (HI) about severe climatic events occurred over short and long timescales. As a matter of fact, natural hazards such as heat waves, droughts, floods, severe storms and snowstorms have affected France and many European countries since the dawn of time. These events would have been such horrific experiences that if they really occurred, there would be unmistakable traces of them. They must have left clues. These catastrophic events have been unforgettably engraved in people's minds and many of them have been traced in archives and history textbooks. The oldest events have certainly left clues and traces somewhere in the geological layers of the earth or elsewhere. The construction of the historical databases and developing probabilistic approaches capable of integrating them correctly is highly challenging for the scientific community (Translating these geological clues to historical data to build historical databases that can be used by the statistical models is a different

  4. The ClimaGrowing Footprint of Climate Change: Can Systems Built Today Cope with Tomorrow's Weather Extremes?

    SciTech Connect

    Kintner-Meyer, Michael CW; Kraucunas, Ian P.

    2013-07-11

    This article describes how current climate conditions--with increasingly extreme storms, droughts, and heat waves and their ensuing effects on water quality and levels--are adding stress to an already aging power grid. Moreover, it explains how evaluations of said grid, built upon past weather patterns, are inaqeduate for measuring if the nation's energy systems can cope with future climate changes. The authors make the case for investing in the development of robust, integrated electricity planning tools that account for these climate change factors as a means for enhancing electricity infrastructure resilience.

  5. Development of National Future Extreme Heat Scenario to Enable the Assessment of Climate Impacts on Public Health

    NASA Technical Reports Server (NTRS)

    Quattrochi, Dale A.; Cresson, William L.; Al-Hamdan, Mohammad Z.; Estes, Maurice G.

    2013-01-01

    The project's emphasis is on providing assessments of the magnitude, frequency and geographic distribution of EHEs to facilitate public health studies. We focus on the daily to weekly time scales on which EHEs occur, not on decadal-scale climate changes. There is, however, a very strong connection between air temperature patterns at the two time scales and long-term climatic changes will certainly alter the frequency of EHEs.

  6. Extreme climatic events drive mammal irruptions: regression analysis of 100-year trends in desert rainfall and temperature

    PubMed Central

    Greenville, Aaron C; Wardle, Glenda M; Dickman, Chris R

    2012-01-01

    Extreme climatic events, such as flooding rains, extended decadal droughts and heat waves have been identified increasingly as important regulators of natural populations. Climate models predict that global warming will drive changes in rainfall and increase the frequency and severity of extreme events. Consequently, to anticipate how organisms will respond we need to document how changes in extremes of temperature and rainfall compare to trends in the mean values of these variables and over what spatial scales the patterns are consistent. Using the longest historical weather records available for central Australia – 100 years – and quantile regression methods, we investigate if extreme climate events have changed at similar rates to median events, if annual rainfall has increased in variability, and if the frequency of large rainfall events has increased over this period. Specifically, we compared local (individual weather stations) and regional (Simpson Desert) spatial scales, and quantified trends in median (50th quantile) and extreme weather values (5th, 10th, 90th, and 95th quantiles). We found that median and extreme annual minimum and maximum temperatures have increased at both spatial scales over the past century. Rainfall changes have been inconsistent across the Simpson Desert; individual weather stations showed increases in annual rainfall, increased frequency of large rainfall events or more prolonged droughts, depending on the location. In contrast to our prediction, we found no evidence that intra-annual rainfall had become more variable over time. Using long-term live-trapping records (22 years) of desert small mammals as a case study, we demonstrate that irruptive events are driven by extreme rainfalls (>95th quantile) and that increases in the magnitude and frequency of extreme rainfall events are likely to drive changes in the populations of these species through direct and indirect changes in predation pressure and wildfires. PMID:23170202

  7. Interannual variability in associations between seasonal climate, weather, and extremes: wintertime temperature over the Southwestern United States

    NASA Astrophysics Data System (ADS)

    Guirguis, Kristen; Gershunov, Alexander; Cayan, Daniel R.

    2015-12-01

    Temperature variability in the Southwest US is investigated using skew-normal probability distribution functions (SN PDFs) fitted to observed wintertime daily maximum temperature records. These PDFs vary significantly between years, with important geographical differences in the relationship between the central tendency and tails, revealing differing linkages between weather and climate. The warmest and coldest extremes do not necessarily follow the distribution center. In some regions one tail of the distribution shows more variability than does the other. For example, in California the cold tail is more variable while the warm tail remains relatively stable, so warm years are associated with fewer cold extremes but not necessarily more warm extremes. The opposite relationship is seen in the Great Plains. Changes in temperature PDFs are conditioned by different phases of El Niño-La Niña (ENSO) and the Pacific decadal oscillation (PDO). In the Southern Great Plains, La Niña and/or negative PDO are associated with generally warmer conditions. However, in terms of extremes, while the warm tails become thicker and longer, the cool tails are not impacted—extremely warm days become more frequent but extremely cool days are not less frequent. In contrast, in coastal California, La Niña or negative PDO bring generally cooler conditions with more/stronger cold extremes but the warm extreme probability is not significantly affected. These results could have implications for global warming. If a rigid shift of the whole range occurs, then warm years are not necessarily a good analogue for a warmer climate. If global warming instead brings regional changes more aligned with a preferred state of dominant climate variability modes, then we may see asymmetric changes in the tails of local temperature PDFs.

  8. Regional and Household Adaptation Strategies to Climate Extremes: the Case Study of the Beava River Basin, the Czech Republic

    NASA Astrophysics Data System (ADS)

    Duží, Barbora; Stojanov, Robert; Vikhrov, Dmytro

    2013-04-01

    We investigate regional and household adaptation strategies in the region affected by climate extremes, focusing on floods occurrence during past 15 years period. The main research question is: What is the overall state of adaptation measurements to climate extremes on the Bečva river basin? Target area is located along upper and middle part of the Bečva river basin in the east of the Czech Republic. The main theoretical concepts draw from differentiations between coping/adaptation strategies to climate extremes and theory of focusing event as a starter of changes in attention and agenda of problem solution. We apply mixed empirical research and case study approach. First we use qualitative research to serve as an initial entrance to the issue, to find out the perception of adaptation progress and preparedness to climate extremes on regional level. We conducted deep interviews (N=20) with relevant stakeholders. We proceed with quantitative research through the conducting face-to face questionnaires with household residents (N=305) in no, low and no risk area in relation to flood occurrence. We designed set of questions to find out relation among experiences with flood, the level of damages and applied emergency and adaptation measurements.

  9. Water-Borne Diseases and Extreme Weather Events in Cambodia: Review of Impacts and Implications of Climate Change

    PubMed Central

    Davies, Grace I.; McIver, Lachlan; Kim, Yoonhee; Hashizume, Masahiro; Iddings, Steven; Chan, Vibol

    2014-01-01

    Cambodia is prone to extreme weather events, especially floods, droughts and typhoons. Climate change is predicted to increase the frequency and intensity of such events. The Cambodian population is highly vulnerable to the impacts of these events due to poverty; malnutrition; agricultural dependence; settlements in flood-prone areas, and public health, governance and technological limitations. Yet little is known about the health impacts of extreme weather events in Cambodia. Given the extremely low adaptive capacity of the population, this is a crucial knowledge gap. A literature review of the health impacts of floods, droughts and typhoons in Cambodia was conducted, with regional and global information reviewed where Cambodia-specific literature was lacking. Water-borne diseases are of particular concern in Cambodia, in the face of extreme weather events and climate change, due to, inter alia, a high pre-existing burden of diseases such as diarrhoeal illness and a lack of improved sanitation infrastructure in rural areas. A time-series analysis under quasi-Poisson distribution was used to evaluate the association between floods and diarrhoeal disease incidence in Cambodian children between 2001 and 2012 in 16 Cambodian provinces. Floods were significantly associated with increased diarrhoeal disease in two provinces, while the analysis conducted suggested a possible protective effect from toilets and piped water. Addressing the specific, local pre-existing vulnerabilities is vital to promoting population health resilience and strengthening adaptive capacity to extreme weather events and climate change in Cambodia. PMID:25546280

  10. Water-borne diseases and extreme weather events in Cambodia: review of impacts and implications of climate change.

    PubMed

    Davies, Grace I; McIver, Lachlan; Kim, Yoonhee; Hashizume, Masahiro; Iddings, Steven; Chan, Vibol

    2014-12-23

    Cambodia is prone to extreme weather events, especially floods, droughts and typhoons. Climate change is predicted to increase the frequency and intensity of such events. The Cambodian population is highly vulnerable to the impacts of these events due to poverty; malnutrition; agricultural dependence; settlements in flood-prone areas, and public health, governance and technological limitations. Yet little is known about the health impacts of extreme weather events in Cambodia. Given the extremely low adaptive capacity of the population, this is a crucial knowledge gap. A literature review of the health impacts of floods, droughts and typhoons in Cambodia was conducted, with regional and global information reviewed where Cambodia-specific literature was lacking. Water-borne diseases are of particular concern in Cambodia, in the face of extreme weather events and climate change, due to, inter alia, a high pre-existing burden of diseases such as diarrhoeal illness and a lack of improved sanitation infrastructure in rural areas. A time-series analysis under quasi-Poisson distribution was used to evaluate the association between floods and diarrhoeal disease incidence in Cambodian children between 2001 and 2012 in 16 Cambodian provinces. Floods were significantly associated with increased diarrhoeal disease in two provinces, while the analysis conducted suggested a possible protective effect from toilets and piped water. Addressing the specific, local pre-existing vulnerabilities is vital to promoting population health resilience and strengthening adaptive capacity to extreme weather events and climate change in Cambodia.

  11. Modelling the increased frequency of extreme sea levels in the Ganges-Brahmaputra-Meghna delta due to sea level rise and other effects of climate change.

    PubMed

    Kay, S; Caesar, J; Wolf, J; Bricheno, L; Nicholls, R J; Saiful Islam, A K M; Haque, A; Pardaens, A; Lowe, J A

    2015-07-01

    Coastal flooding due to storm surge and high tides is a serious risk for inhabitants of the Ganges-Brahmaputra-Meghna (GBM) delta, as much of the land is close to sea level. Climate change could lead to large areas of land being subject to increased flooding, salinization and ultimate abandonment in West Bengal, India, and Bangladesh. IPCC 5th assessment modelling of sea level rise and estimates of subsidence rates from the EU IMPACT2C project suggest that sea level in the GBM delta region may rise by 0.63 to 0.88 m by 2090, with some studies suggesting this could be up to 0.5 m higher if potential substantial melting of the West Antarctic ice sheet is included. These sea level rise scenarios lead to increased frequency of high water coastal events. Any effect of climate change on the frequency and severity of storms can also have an effect on extreme sea levels. A shelf-sea model of the Bay of Bengal has been used to investigate how the combined effect of sea level rise and changes in other environmental conditions under climate change may alter the frequency of extreme sea level events for the period 1971 to 2099. The model was forced using atmospheric and oceanic boundary conditions derived from climate model projections and the future scenario increase in sea level was applied at its ocean boundary. The model results show an increased likelihood of extreme sea level events through the 21st century, with the frequency of events increasing greatly in the second half of the century: water levels that occurred at decadal time intervals under present-day model conditions occurred in most years by the middle of the 21st century and 3-15 times per year by 2100. The heights of the most extreme events tend to increase more in the first half of the century than the second. The modelled scenarios provide a case study of how sea level rise and other effects of climate change may combine to produce a greatly increased threat to life and property in the GBM delta by the end

  12. Modelling the increased frequency of extreme sea levels in the Ganges-Brahmaputra-Meghna delta due to sea level rise and other effects of climate change.

    PubMed

    Kay, S; Caesar, J; Wolf, J; Bricheno, L; Nicholls, R J; Saiful Islam, A K M; Haque, A; Pardaens, A; Lowe, J A

    2015-07-01

    Coastal flooding due to storm surge and high tides is a serious risk for inhabitants of the Ganges-Brahmaputra-Meghna (GBM) delta, as much of the land is close to sea level. Climate change could lead to large areas of land being subject to increased flooding, salinization and ultimate abandonment in West Bengal, India, and Bangladesh. IPCC 5th assessment modelling of sea level rise and estimates of subsidence rates from the EU IMPACT2C project suggest that sea level in the GBM delta region may rise by 0.63 to 0.88 m by 2090, with some studies suggesting this could be up to 0.5 m higher if potential substantial melting of the West Antarctic ice sheet is included. These sea level rise scenarios lead to increased frequency of high water coastal events. Any effect of climate change on the frequency and severity of storms can also have an effect on extreme sea levels. A shelf-sea model of the Bay of Bengal has been used to investigate how the combined effect of sea level rise and changes in other environmental conditions under climate change may alter the frequency of extreme sea level events for the period 1971 to 2099. The model was forced using atmospheric and oceanic boundary conditions derived from climate model projections and the future scenario increase in sea level was applied at its ocean boundary. The model results show an increased likelihood of extreme sea level events through the 21st century, with the frequency of events increasing greatly in the second half of the century: water levels that occurred at decadal time intervals under present-day model conditions occurred in most years by the middle of the 21st century and 3-15 times per year by 2100. The heights of the most extreme events tend to increase more in the first half of the century than the second. The modelled scenarios provide a case study of how sea level rise and other effects of climate change may combine to produce a greatly increased threat to life and property in the GBM delta by the end

  13. Impacts of