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. Climatic Extremes Significantly Alter Carbon Fluxes in Time and Space

    NASA Astrophysics Data System (ADS)

    Chen, J.; Ouyan, Z.; John, R.; Chu, H.; Zenone, T.; Deal, M.; Gottgens, J.

    2012-12-01

    It has been increasingly evident that climatic extremes play crucial roles in the magnitudes and directions of carbon fluxes. However, significantly less is known about how these effects may change across multiple time and spatial scales. Here we used several databases collected from eddy-covariance (EC) towers and MODIS to understand these effects for: 1) long-term influences at an oak opening site (i.e. single site); 2) a cluster of EC fluxes from the Maumee watershed (i.e. different ecosystem types under the same climate); 3) several agricultural systems in the Midwest (i.e., same ecosystem among different climates); and 4) long term EVI, ET, GPP and LST (2000-2011) impacts across the Mongolia Plateau. We employed various wavelet analyses (transform, variance, coherency, and cross-wavelet) for the temporal data while an anomaly index was calculated for the spatial data on the plateau. As expected, the occurrences of extreme events and their influences varied greatly by year, but all produced significant and lasting effects on NEE, ER and, particularly on GEP. Three different ecosystems in the Maumee Watershed responded differently in magnitude/direction to the same climate anomaly (e.g. 2012 warmest March on record). Both the beginning time and magnitude of the NEE oscillation of the daily period at Oak Openings and the marshland were influenced by the unusual high March temperature, but the cropland ecosystem was less influenced because crops were not sown until the end of spring. Similarly, crops in different climates responded differently to the similar extremes. Across the broader spatiotemporal scales, we found that the forest biome more resistant to climatic extremes than the grassland and desert biomes on Mongolia Plateau. Frequency distributions of standardized anomalies of EVI during 2000-2010 showed that a number of the positively skewed years were more common in the desert biome compared to grasslands and forests. Positively skewed drought years

  3. 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

  4. CO2 and H2O fluxes in different ecosystems altered uniquely by similar climatic extremes

    NASA Astrophysics Data System (ADS)

    Chu, H.; Chen, J.; Ouyang, Z.; Deal, M.; John, R.; Gottgens, J.

    2012-12-01

    Using flux measurements at three contrasting ecosystems under similar climatic conditions, we examined the responses of an oak savanna (OO), freshwater marsh (ML), and cropland (CL) in the Maumee watershed in Northwest Ohio to an extremely warm winter and spring. The 2012 winter (Dec 1st to Feb 28th) was recorded as one of the warmest (averaged ~0.3 °C) and snowless (16 days with ground snow cover) winters in the past 50 years (-3.1 °C and 34 days) in the region. This was followed by a warmer spring (11.1 °C, compared to 50-yr average of 8.9 °C) that triggered early leaf emergence. The ecosystem CO2 and H2O water fluxes measured with eddy covariance towers from July 2010 to July 2012 were used to quantify responses to these extremes. The start of growing season (SGS) was ~7 and ~10 days earlier in OO and CL in 2012 than in 2011, respectively, but ~5 days later in ML. All three sites showed extreme CO2 emission and evapotranspiration (ET) with ML displaying the most dramatic responses (increased 43g C m-2 emission and 88 mm ET from Dec 1st to SGS). The cumulative CO2 emission through the winter to SGS in 2012 were 117, 64, and 119 g C m-2 at OO, ML and CL, respectively, and were higher than those of 2011 (110, 21, and 111 g C m-2). These higher CO2 emissions were compensated by earlier onset of growing season at OO and CL, leading to a CO2 budget of -406 and 61 g C m-2 at the peak of growing season in late July. The CO2 budgets at OO and CL were both elevated in 2012 over the -331 and 87 g C m-2 in 2011. The CO2 budget at ML was 26 g C m-2 starting from Dec 1st, 2011 to late July, 2012, contrasting with -32 g C m-2 in previous year. The cumulative ET through the winter to SGS in 2012 was 74, 218, and 238 mm at OO, ML and CL, respectively, with a cumulative precipitation of 289, 279 and 425 mm. While cumulative precipitation through the winter to SGS was higher in 2011 (344, 296, and 427 mm at OO, ML and CL), the cumulative ET was, in contrast, lower in 2011 (56

  5. 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).

  6. Precipitation Extremes Under Climate Change.

    PubMed

    O'Gorman, Paul A

    The response of precipitation extremes to climate change is considered using results from theory, modeling, and observations, with a focus on the physical factors that control the response. Observations and simulations with climate models show that precipitation extremes intensify in response to a warming climate. However, the sensitivity of precipitation extremes to warming remains uncertain when convection is important, and it may be higher in the tropics than the extratropics. Several physical contributions govern the response of precipitation extremes. The thermodynamic contribution is robust and well understood, but theoretical understanding of the microphysical and dynamical contributions is still being developed. Orographic precipitation extremes and snowfall extremes respond differently from other precipitation extremes and require particular attention. Outstanding research challenges include the influence of mesoscale convective organization, the dependence on the duration considered, and the need to better constrain the sensitivity of tropical precipitation extremes to warming.

  7. Climate Extremes and Forest Carbon Sequestration Capacities

    NASA Astrophysics Data System (ADS)

    Wei, S.; Yi, C.; Hendrey, G. R.; Eaton, T. T.; Liu, H.; Rustic, G. T.; Krakauer, N.; Wang, S.

    2013-12-01

    Several lines of evidence suggest that the warming climate plays a vital role in driving certain types of extreme weather. How these extreme climates affect forest carbon sequestration capacity is unknown. This knowledge gap is critical in understanding positive feedbacks to global warming by changing the amount of carbon that forests can hold. Here, we used a perfect-deficit approach to identify forest canopy photosynthetic capacity (CPC) deficits and analyze how they correlate to climate extremes, based on data measured by the eddy covariance method at 26 forest sites with total of 146 site-years. We found that droughts severely alter the carbon sequestration capacities of evergreen broadleaf forest and deciduous broadleaf forest. In addition, the carbon sequestration capacities of Mediterranean forests are mostly sensitive to climate extremes while that of forests under marine climate are insensitive to climate extremes. Acknowledgements This research was financially supported by PSC-CUNY Award (PSC-CUNY-ENHC-44-83) and National Science Foundation (NSF-DEB-0949637).

  8. 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?

  9. 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

  10. Will extreme climatic events facilitate biological invasions?

    USDA-ARS?s Scientific Manuscript database

    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...

  11. 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.

  12. 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.

  13. Extreme Weather and Climate: Workshop Report

    NASA Technical Reports Server (NTRS)

    Sobel, Adam; Camargo, Suzana; Debucquoy, Wim; Deodatis, George; Gerrard, Michael; Hall, Timothy; Hallman, Robert; Keenan, Jesse; Lall, Upmanu; Levy, Marc; hide

    2016-01-01

    Extreme events are the aspects of climate to which human society is most sensitive. Due to both their severity and their rarity, extreme events can challenge the capacity of physical, social, economic and political infrastructures, turning natural events into human disasters. Yet, because they are low frequency events, the science of extreme events is very challenging. Among the challenges is the difficulty of connecting extreme events to longer-term, large-scale variability and trends in the climate system, including anthropogenic climate change. How can we best quantify the risks posed by extreme weather events, both in the current climate and in the warmer and different climates to come? How can we better predict them? What can we do to reduce the harm done by such events? In response to these questions, the Initiative on Extreme Weather and Climate has been created at Columbia University in New York City (extreme weather.columbia.edu). This Initiative is a University-wide activity focused on understanding the risks to human life, property, infrastructure, communities, institutions, ecosystems, and landscapes from extreme weather events, both in the present and future climates, and on developing solutions to mitigate those risks. In May 2015,the Initiative held its first science workshop, entitled Extreme Weather and Climate: Hazards, Impacts, Actions. The purpose of the workshop was to define the scope of the Initiative and tremendously broad intellectual footprint of the topic indicated by the titles of the presentations (see Table 1). The intent of the workshop was to stimulate thought across disciplinary lines by juxtaposing talks whose subjects differed dramatically. Each session concluded with question and answer panel sessions. Approximately, 150 people were in attendance throughout the day. Below is a brief synopsis of each presentation. The synopses collectively reflect the variety and richness of the emerging extreme event research agenda.

  14. Extreme Weather and Climate: Workshop Report

    NASA Technical Reports Server (NTRS)

    Sobel, Adam; Camargo, Suzana; Debucquoy, Wim; Deodatis, George; Gerrard, Michael; Hall, Timothy; Hallman, Robert; Keenan, Jesse; Lall, Upmanu; Levy, Marc; Orlove, Ben; Rosenzweig, Cynthia; Seager, Richard; Shaman, Jeffrey; Tippett, Michael

    2016-01-01

    Extreme events are the aspects of climate to which human society is most sensitive. Due to both their severity and their rarity, extreme events can challenge the capacity of physical, social, economic and political infrastructures, turning natural events into human disasters. Yet, because they are low frequency events, the science of extreme events is very challenging. Among the challenges is the difficulty of connecting extreme events to longer-term, large-scale variability and trends in the climate system, including anthropogenic climate change. How can we best quantify the risks posed by extreme weather events, both in the current climate and in the warmer and different climates to come? How can we better predict them? What can we do to reduce the harm done by such events? In response to these questions, the Initiative on Extreme Weather and Climate has been created at Columbia University in New York City (extreme weather.columbia.edu). This Initiative is a University-wide activity focused on understanding the risks to human life, property, infrastructure, communities, institutions, ecosystems, and landscapes from extreme weather events, both in the present and future climates, and on developing solutions to mitigate those risks. In May 2015,the Initiative held its first science workshop, entitled Extreme Weather and Climate: Hazards, Impacts, Actions. The purpose of the workshop was to define the scope of the Initiative and tremendously broad intellectual footprint of the topic indicated by the titles of the presentations (see Table 1). The intent of the workshop was to stimulate thought across disciplinary lines by juxtaposing talks whose subjects differed dramatically. Each session concluded with question and answer panel sessions. Approximately, 150 people were in attendance throughout the day. Below is a brief synopsis of each presentation. The synopses collectively reflect the variety and richness of the emerging extreme event research agenda.

  15. Climate change, climatic variation and extreme biological responses

    PubMed Central

    Brereton, Tom; Chapman, Jason W.; Dytham, Calvin; Fox, Richard; Pearce-Higgins, James W.; Roy, David B.; Hill, Jane K.; Thomas, Chris D.

    2017-01-01

    Extreme climatic events could be major drivers of biodiversity change, but it is unclear whether extreme biological changes are (i) individualistic (species- or group-specific), (ii) commonly associated with unusual climatic events and/or (iii) important determinants of long-term population trends. Using population time series for 238 widespread species (207 Lepidoptera and 31 birds) in England since 1968, we found that population ‘crashes’ (outliers in terms of species' year-to-year population changes) were 46% more frequent than population ‘explosions’. (i) Every year, at least three species experienced extreme changes in population size, and in 41 of the 44 years considered, some species experienced population crashes while others simultaneously experienced population explosions. This suggests that, even within the same broad taxonomic groups, species are exhibiting individualistic dynamics, most probably driven by their responses to different, short-term events associated with climatic variability. (ii) Six out of 44 years showed a significant excess of species experiencing extreme population changes (5 years for Lepidoptera, 1 for birds). These ‘consensus years’ were associated with climatically extreme years, consistent with a link between extreme population responses and climatic variability, although not all climatically extreme years generated excess numbers of extreme population responses. (iii) Links between extreme population changes and long-term population trends were absent in Lepidoptera and modest (but significant) in birds. We conclude that extreme biological responses are individualistic, in the sense that the extreme population changes of most species are taking place in different years, and that long-term trends of widespread species have not, to date, been dominated by these extreme changes. This article is part of the themed issue ‘Behavioural, ecological and evolutionary responses to extreme climatic events’. PMID:28483874

  16. Regional Changes in Extreme Climatic Events

    NASA Astrophysics Data System (ADS)

    Bell, J. L.; Sloan, L. C.; Snyder, M. A.

    2002-12-01

    This study focuses on California as a climatically complex region that is vulnerable to changes in water supply and delivery. A regional climate model is employed to assess changes in the frequency and intensity of extreme temperatures and precipitation. Significant increases in daily minimum and maximum temperatures occur with a doubling of atmospheric carbon dioxide concentration. Increases in daily temperatures lead to increases in prolonged heat waves and length of the growing season. Changes in total and extreme precipitation vary by geographic region.

  17. 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.

  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. 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

  20. 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

  1. 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. © 2011 Blackwell Publishing Ltd/CNRS.

  2. Ongoing climatic extreme dynamics in Siberia

    NASA Astrophysics Data System (ADS)

    Gordov, E. P.; Shulgina, T. M.; Okladnikov, I. G.; Titov, A. G.

    2013-12-01

    Ongoing global climate changes accompanied by the restructuring of global processes in the atmosphere and biosphere are strongly pronounced in the Northern Eurasia regions, especially in Siberia. Recent investigations indicate not only large changes in averaged climatic characteristics (Kabanov and Lykosov, 2006, IPCC, 2007; Groisman and Gutman, 2012), but more frequent occurrence and stronger impacts of climatic extremes are reported as well (Bulygina et al., 2007; IPCC, 2012: Climate Extremes, 2012; Oldenborh et al., 2013). This paper provides the results of daily temperature and precipitation extreme dynamics in Siberia for the last three decades (1979 - 2012). Their seasonal dynamics is assessed using 10th and 90th percentile-based threshold indices that characterize frequency, intensity and duration of climatic extremes. To obtain the geographical pattern of these variations with high spatial resolution, the sub-daily temperature data from ECMWF ERA-Interim reanalysis and daily precipitation amounts from APHRODITE JMA dataset were used. All extreme indices and linear trend coefficients have been calculated using web-GIS information-computational platform Climate (http://climate.scert.ru/) developed to support collaborative multidisciplinary investigations of regional climatic changes and their impacts (Gordov et al., 2012). Obtained results show that seasonal dynamics of daily temperature extremes is asymmetric for tails of cold and warm temperature extreme distributions. Namely, the intensity of warming during cold nights is higher than during warm nights, especially at high latitudes of Siberia. The similar dynamics is observed for cold and warm day-time temperatures. Slight summer cooling was observed in the central part of Siberia. It is associated with decrease in warm temperature extremes. In the southern Siberia in winter, we also observe some cooling mostly due to strengthening of the cold temperature extremes. Changes in daily precipitation extremes

  3. Extreme Weather Events and Climate Change Attribution

    SciTech Connect

    Thomas, Katherine

    2016-03-31

    A report from the National Academies of Sciences, Engineering, and Medicine concludes it is now possible to estimate the influence of climate change on some types of extreme events. The science of extreme event attribution has advanced rapidly in recent years, giving new insight to the ways that human-caused climate change can influence the magnitude or frequency of some extreme weather events. This report examines the current state of science of extreme weather attribution, and identifies ways to move the science forward to improve attribution capabilities. Confidence is strongest in attributing types of extreme events that are influenced by climate change through a well-understood physical mechanism, such as, the more frequent heat waves that are closely connected to human-caused global temperature increases, the report finds. Confidence is lower for other types of events, such as hurricanes, whose relationship to climate change is more complex and less understood at present. For any extreme event, the results of attribution studies hinge on how questions about the event's causes are posed, and on the data, modeling approaches, and statistical tools chosen for the analysis.

  4. 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.

  5. 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.

  6. Seasonal Climate Extremes : Mechanism, Predictability and Responses to Global Warming

    NASA Astrophysics Data System (ADS)

    Shongwe, M. E.

    2010-01-01

    energy and dynamic horizontal advection of heat. There is clear evidence that the central North Atlantic Ocean was the major source of energy for the Autumn 2006 extreme event. Within Europe, anomalously high atmospheric water-vapor loading played a significant role through its strong greenhouse effect which resulted in an increase of downwelling infrared flux to the surface. Potential influences and connections between boreal snow cover during the melt season (February--April) and near-surface temperature in the spring season are established. Large amounts of snow act as a precursor to cold spring seasons by altering the coupling between the land and the overlying air through a modification of the surface energy and hydrological processes. In operational numerical models, a snow signal is found to provide some seasonal forecast skill for cold spring seasons in Europe. Changes in the intensity of droughts and floods in Africa in response to global warming are investigated and compared with changes in mean precipitation simulated by an ensemble of climate models selected from the Intergovernmental Panel on Climate Change (IPCC) fourth assessment report (AR4) set. The model simulations are objectively combined using a Bayesian weighting procedure. In southern Africa south of about 15° S, the most robust climate-change signal is a shortening of the main rainfall season. This arises from a delayed onset of seasonal rainfall associated with a reduction in lower-tropospheric moisture advection from the southwestern Indian Ocean. The semi-arid areas closer to the Kalahari desert are projected to become drier, while the wet areas are projected to become wetter. East Africa is projected to get wet in the future climate, much wetter than other regions within the same latitudinal belt. The zonal asymmetry in tropical precipitation increase is associated with a shift towards positive Indian Ocean Zonal Mode (IOZM)-like events via an alteration in the structure of the Eastern

  7. The Engineering for Climate Extremes Partnership

    NASA Astrophysics Data System (ADS)

    Holland, G. J.; Tye, M. R.

    2014-12-01

    Hurricane Sandy and the recent floods in Thailand have demonstrated not only how sensitive the urban environment is to the impact of severe weather, but also the associated global reach of the ramifications. These, together with other growing extreme weather impacts and the increasing interdependence of global commercial activities point towards a growing vulnerability to weather and climate extremes. The Engineering for Climate Extremes Partnership brings academia, industry and government together with the goals encouraging joint activities aimed at developing new, robust, and well-communicated responses to this increasing vulnerability. Integral to the approach is the concept of 'graceful failure' in which flexible designs are adopted that protect against failure by combining engineering or network strengths with a plan for efficient and rapid recovery if and when they fail. Such an approach enables optimal planning for both known future scenarios and their assessed uncertainty.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. Changes in climate extremes indices over Mexico

    NASA Astrophysics Data System (ADS)

    Teufel, B. S.; Mora Rodriguez, J.; Pineda-Martinez, L. F.

    2013-05-01

    There is scientific consensus on the fact that any change in the frequency or intensity of climate extremes (one of the consequences of global climate change) will have a great impact on the environment and on society. There has been an international effort, led by the Expert Team on Climate Change Detection and Indices (ETCCDI), to develop a set of climate extremes indices, so individuals, regions and countries can calculate such indices in the same way, enabling them to be compared across borders. Daily records of temperature and precipitation are required to calculate these climate extremes indices and their behavior over long periods shows if the frequency or intensity of climate extremes has changed. For this work, the full database of the National Meteorological Service of Mexico (Servicio Meteorologico Nacional), which contains data for over 5000 meteorological stations, was used. First, quality control and homogeneity procedures, as recommended by the World Meteorological Organization (WMO), were used to analyze and filter the database, removing erroneous or inconsistent data. The following climate indices were obtained for all stations that met the WMO's criteria for calculating climate normals: - Percentage of days with daily minimum temperatures lower than the 10th percentile. - Percentage of days with daily maximum temperatures lower than the 10th percentile. - Percentage of days with daily minimum temperatures higher than the 90th percentile. - Percentage of days with daily maximum temperatures higher than the 90th percentile. - Percentage of days with daily precipitation above the 95th percentile. - Percentage of days with daily precipitation above the 99th percentile. The results are presented as regionally averaged time series for the period 1930 - 2010. Additionally, the spatial distribution of the magnitude and statistical significance of the changes in the indices is presented. Widespread and statistically significant changes in the temperature

  13. 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.

  14. Attribution of extreme weather and climate-related events.

    PubMed

    Stott, Peter A; Christidis, Nikolaos; Otto, Friederike E L; Sun, Ying; Vanderlinden, Jean-Paul; van Oldenborgh, Geert Jan; Vautard, Robert; von Storch, Hans; Walton, Peter; Yiou, Pascal; Zwiers, Francis W

    2016-01-01

    Extreme weather and climate-related events occur in a particular place, by definition, infrequently. It is therefore challenging to detect systematic changes in their occurrence given the relative shortness of observational records. However, there is a clear interest from outside the climate science community in the extent to which recent damaging extreme events can be linked to human-induced climate change or natural climate variability. Event attribution studies seek to determine to what extent anthropogenic climate change has altered the probability or magnitude of particular events. They have shown clear evidence for human influence having increased the probability of many extremely warm seasonal temperatures and reduced the probability of extremely cold seasonal temperatures in many parts of the world. The evidence for human influence on the probability of extreme precipitation events, droughts, and storms is more mixed. Although the science of event attribution has developed rapidly in recent years, geographical coverage of events remains patchy and based on the interests and capabilities of individual research groups. The development of operational event attribution would allow a more timely and methodical production of attribution assessments than currently obtained on an ad hoc basis. For event attribution assessments to be most useful, remaining scientific uncertainties need to be robustly assessed and the results clearly communicated. This requires the continuing development of methodologies to assess the reliability of event attribution results and further work to understand the potential utility of event attribution for stakeholder groups and decision makers. WIREs Clim Change 2016, 7:23-41. doi: 10.1002/wcc.380 For further resources related to this article, please visit the WIREs website.

  15. Climate Extremes and the Length of Gestation

    PubMed Central

    Basagaña, Xavier; Sartini, Claudio; Figueras, Francesc; Vrijheid, Martine; de Nazelle, Audrey; Sunyer, Jordi; Nieuwenhuijsen, Mark J.

    2011-01-01

    Background: Although future climate is predicted to have more extreme heat conditions, the available evidence on the impact of these conditions on pregnancy length is very scarce and inconclusive. Objectives: We investigated the impact of maternal short-term exposure to extreme ambient heat on the length of pregnancy. Methods: This study was based on a cohort of births that occurred in a major university hospital in Barcelona during 2001–2005. Three indicators of extreme heat conditions based on 1-day exposure to an unusually high heat–humidity index were applied. Each mother was assigned the measures made by the meteorological station closest to maternal residential postcodes. A two-stage analysis was developed to quantify the change in pregnancy length after maternal exposure to extreme heat conditions adjusted for a range of covariates. The second step was repeated for lags 0 (delivery date) to 6 days. Results: We included data from 7,585 pregnant women in our analysis. We estimated a 5-day reduction in average gestational age at delivery after an unusually high heat–humidity index on the day before delivery. Conclusion: Extreme heat was associated with a reduction in the average gestational age of children delivered the next day, suggesting an immediate effect of this exposure on pregnant women. Further studies are required to confirm our findings in different settings. PMID:21659038

  16. 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

  17. 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

  18. 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.

  19. Climate Extreme Events over Northern Eurasia in Changing Climate

    NASA Astrophysics Data System (ADS)

    Bulygina, O.; Korshunova, N. N.; Razuvaev, V. N.; Groisman, P. Y.

    2014-12-01

    During the period of widespread instrumental observations in Northern Eurasia, the annual surface air temperature has increased by 1.5°C. Close to the north in the Arctic Ocean, the late summer sea ice extent has decreased by 40% providing a near-infinite source of water vapor for the dry Arctic atmosphere in the early cold season months. The contemporary sea ice changes are especially visible in the Eastern Hemisphere All these factors affect the change extreme events. Daily and sub-daily data of 940 stations to analyze variations in the space time distribution of extreme temperatures, precipitation, and wind over Russia were used. Changing in number of days with thaw over Russia was described. The total seasonal numbers of days, when daily surface air temperatures (wind, precipitation) were found to be above (below) selected thresholds, were used as indices of climate extremes. Changing in difference between maximum and minimum temperature (DTR) may produce a variety of effects on biological systems. All values falling within the intervals ranged from the lowest percentile to the 5th percentile and from the 95th percentile to the highest percentile for the time period of interest were considered as daily extremes. The number of days, N, when daily temperatures (wind, precipitation, DTR) were within the above mentioned intervals, was determined for the seasons of each year. Linear trends in the number of days were calculated for each station and for quasi-homogeneous climatic regions. Regional analysis of extreme events was carried out using quasi-homogeneous climatic regions. Maps (climatology, trends) are presented mostly for visualization purposes. Differences in regional characteristics of extreme events are accounted for over a large extent of the Russian territory and variety of its physical and geographical conditions. The number of days with maximum temperatures higher than the 95% percentile has increased in most of Russia and decreased in Siberia in

  20. 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.

  1. 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.

  2. Climate teleconnections, weather extremes, and vector-borne disease outbreaks

    USDA-ARS?s Scientific Manuscript database

    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...

  3. Influence of Climate Oscillations on Extreme Precipitation in Texas

    NASA Astrophysics Data System (ADS)

    Bhatia, N.; Singh, V. P.; Srivastav, R. K.

    2016-12-01

    Much research in the field of hydroclimatology is focusing on the impact of climate variability on hydrologic extremes. Recent studies show that the unique geographical location and the enormous areal extent, coupled with extensive variations in climate oscillations, have intensified the regional hydrologic cycle of Texas. The state-wide extreme precipitation events can actually be attributed to sea-surface pressure and temperature anomalies, such as Bermuda High and Jet Streams, which are further triggered by such climate oscillations. This study aims to quantify the impact of five major Atlantic and Pacific Ocean related climate oscillations: (i) Atlantic Multidecadal Oscillation (AMO), (ii) North Atlantic Oscillation (NAO), (iii) Pacific Decadal Oscillation (PDO), (iv) Pacific North American Pattern (PNA), and (v) Southern Oscillation Index (SOI), on extreme precipitation in Texas. Their respective effects will be determined for both climate divisions delineated by the National Climatic Data Centre (NCDC) and climate regions defined by the Köppen Climate Classification System. This study will adopt a weighted correlation approach to attain the robust correlation coefficients while addressing the regionally variable data outliers for extreme precipitation. Further, the variation of robust correlation coefficients across Texas is found to be related to the station elevation, historical average temperature, and total precipitation in the months of extremes. The research will shed light on the relationship between precipitation extremes and climate variability, thus aiding regional water boards in planning, designing, and managing the respective systems as per the future climate change.

  4. Detection and attribution of climate extremes in the observed record

    SciTech Connect

    Easterling, David R.; Kunkel, Kenneth E.; Wehner, Michael F.; Sun, Liqiang

    2016-01-18

    We present an overview of practices and challenges related to the detection and attribution of observed changes in climate extremes. Detection is the identification of a statistically significant change in the extreme values of a climate variable over some period of time. Issues in detection discussed include data quality, coverage, and completeness. Attribution takes that detection of a change and uses climate model simulations to evaluate whether a cause can be assigned to that change. Additionally, we discuss a newer field of attribution, event attribution, where individual extreme events are analyzed for the express purpose of assigning some measure of whether that event was directly influenced by anthropogenic forcing of the climate system.

  5. Research progress of extreme climate and its vegetation response

    NASA Astrophysics Data System (ADS)

    Cui, Xiaolin; Wei, Xiaoqing; Wang, Tao

    2017-08-01

    The IPCC’s fifth assessment report indicates that climate warming is unquestionable, the frequency and intensity of extreme weather events may increase, and extreme weather events can destroy the growth conditions of vegetation that is otherwise in a stable condition. Therefore, it is essential to research the formation of extreme weather events and its ecological response, both in terms scientific development and the needs of societal development. This paper mainly examines these issues from the following aspects: (1) the definition of extreme climate events and the methods of studying the associated response of vegetation; (2) the research progress on extreme climate events and their vegetation response; and (3) the future direction of research on extreme climate and its vegetation response.

  6. 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.

  7. 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

  8. 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

  9. 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

  10. 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.

  11. Multi - Region Analysis of a New Climate Extremes Index

    NASA Astrophysics Data System (ADS)

    Dittus, A. J.; Karoly, D. J.; Lewis, S. C.; Alexander, L. V.

    2014-12-01

    In this study, a new Climate Extremes Index (CEI) is introduced, extending the earlier combined CEI proposed by Karl et al. (1996). It is based on the use of standard extreme indices derived from daily meteorological station data, facilitating the computation of this index and making use of two global gridded extreme indices datasets. The index combines the fraction of area experiencing extreme conditions in daily temperature and daily and annual precipitation, therefore representing a combined measure of extremes. The analysis of this index at the global scale is limited by data availability. In this study, the four continental-scale regions analysed are Europe, North America, Asia and Australia over the period from 1951 to 2010. Additionally, the index is also computed for the entire Northern Hemisphere, corresponding to the first CEI results at the hemispheric scale. Results show statistically significant increases in the percentage area experiencing much above average warm days and nights and much below average cool days and nights for all regions, with the exception of North America for maximum temperature extremes. Increases in the area affected by precipitation extremes are also found for the Northern Hemisphere regions, particularly Europe. This study shows the potential of this new index for climate monitoring and other applications by documenting large-scale changes in the areas experiencing climate extremes. Preliminary detection and attribution results will also be presented using extreme indices computed for the Coupled Model Intercomparison Project Phase 5 climate model simulations (Sillmann et al., 2013). Karl, T. R., R. W. Knight, D. R. Easterling, and R. G. Quayle, 1996: Indices of climate change for the United States. Bull. Amer. Meteor. Soc., 77, 279-292. Sillmann, J., V. V. Kharin, X. Zhang, F. W. Zwiers, and D. Bronaugh (2013), Climate extremes indices in the CMIP5 multimodel ensemble: Part 1. Model evaluation in the present climate, J. Geophys

  12. Overview of the North America Climate Extremes Monitoring (NACEM) System

    NASA Astrophysics Data System (ADS)

    Lawrimore, J. H.; Heim, R. R.

    2007-05-01

    The IPCC Fourth Assessment Report and other climate assessments have documented an increasing trend in temperature and precipitation extremes, including hot days and nights, heavy precipitation events, and area affected by droughts. Extreme weather and climate events such as these often result in significant socioeconomic and environmental costs within affected areas. This reality along with the likelihood that trends toward more frequent and intense extreme events will increase in a warming world has focused attention on programs that can provide information to decision makers responsible for planning, response, and mitigation activities. Several government and university institutions throughout the U.S., Canada, and Mexico have partnered to improve monitoring of extremes across the North American Continent. This effort began in late 2002 with establishment of the North America Drought Monitor (NADM), an operational program for monitoring continent-scale drought conditions on an ongoing basis. Following the NADM, this trilateral partnership initiated development of a web- based climate extremes system to expand the capacity to monitor a wider range of climate extremes. Using daily data from stations across these three countries, the North American Climate Extremes Monitoring (NACEM) system now provides decision makers with the ability to monitor and analyze climate extremes on the continent. The U.S. and Canada are also collaborating in the creation of a near-real time operational component to monitor the occurrence of new daily, monthly, and all-time records for temperature, precipitation, and snowfall as they occur. Parallel development of a North American gridded database of daily temperature and precipitation supports these activities and will soon provide for the analysis of extremes on a regional, country, and continental-scale basis. This presentation will include an overview of the NACEM system and its products, the supporting database, observed changes in

  13. Vulnerability of wheat productivity in Spain to extreme climate indices

    NASA Astrophysics Data System (ADS)

    Rodriguez-Puebla, Concepcion; Hernandez-Barrera, Sara; Gonzalez-Reviriego, Nube; Encinas, Ascension H.

    2013-04-01

    Climate change is one of the major risk for agriculture and it has been reported that statistical values of droughts and temperatures are changing over the Iberian Peninsula. Therefore, we consider of great interest to show results about the potential impacts of temperature, precipitation and extreme climate indices on wheat yield in Spain. First, extreme climate indices derived from daily maximum, minimum temperatures and precipitation are obtained by using E-OBS data over the Iberian Peninsula. Second, we evaluate the relationships between climate indices and wheat productivity. The effects of climate variations on observed wheat is characterized by a model derived from Partial Least Square regression method. This approach is expected to be useful for predicting the impact of climate change on the yield and could be applied for other climate scenarios to learn about the changes in mean and variability of the wheat.

  14. Flight Testing Under Extreme Climatic Conditions

    DTIC Science & Technology

    1988-09-01

    FACILITY .. ........ 33 MCKINLEY CIMATIC LABORATORY .... ............ 34 Climatic Laboratory Description ... ........... 35 Climatic Laboratory...with other changes result- ing from a development program. This assures the availability of a globally effective system in the shortest possible time...procedural changes /improvements implemented and an assessment made of objectives achieved. This assessment sets the stage for preparation of the procedures

  15. Climate extremes: The worst heat waves to come

    NASA Astrophysics Data System (ADS)

    Schär, Christoph

    2016-02-01

    The combination of high temperatures and humidity could, within just a century, result in extreme conditions around the Persian Gulf that are intolerable to humans, if climate change continues unabated.

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

    USDA-ARS?s Scientific Manuscript database

    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, ...

  17. 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.

  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. 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.

  20. 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

  1. Extreme weather and climate events with ecological relevance: a review.

    PubMed

    Ummenhofer, Caroline C; Meehl, Gerald A

    2017-06-19

    Robust evidence exists that certain extreme weather and climate events, especially daily temperature and precipitation extremes, have changed in regard to intensity and frequency over recent decades. These changes have been linked to human-induced climate change, while the degree to which climate change impacts an individual extreme climate event (ECE) is more difficult to quantify. Rapid progress in event attribution has recently been made through improved understanding of observed and simulated climate variability, methods for event attribution and advances in numerical modelling. Attribution for extreme temperature events is stronger compared with other event types, notably those related to the hydrological cycle. Recent advances in the understanding of ECEs, both in observations and their representation in state-of-the-art climate models, open new opportunities for assessing their effect on human and natural systems. Improved spatial resolution in global climate models and advances in statistical and dynamical downscaling now provide climatic information at appropriate spatial and temporal scales. Together with the continued development of Earth System Models that simulate biogeochemical cycles and interactions with the biosphere at increasing complexity, these make it possible to develop a mechanistic understanding of how ECEs affect biological processes, ecosystem functioning and adaptation capabilities. Limitations in the observational network, both for physical climate system parameters and even more so for long-term ecological monitoring, have hampered progress in understanding bio-physical interactions across a range of scales. New opportunities for assessing how ECEs modulate ecosystem structure and functioning arise from better scientific understanding of ECEs coupled with technological advances in observing systems and instrumentation.This article is part of the themed issue 'Behavioural, ecological and evolutionary responses to extreme climatic events

  2. Detection and attribution of climate extremes in the observed record

    DOE PAGES

    Easterling, David R.; Kunkel, Kenneth E.; Wehner, Michael F.; ...

    2016-01-18

    We present an overview of practices and challenges related to the detection and attribution of observed changes in climate extremes. Detection is the identification of a statistically significant change in the extreme values of a climate variable over some period of time. Issues in detection discussed include data quality, coverage, and completeness. Attribution takes that detection of a change and uses climate model simulations to evaluate whether a cause can be assigned to that change. Additionally, we discuss a newer field of attribution, event attribution, where individual extreme events are analyzed for the express purpose of assigning some measure ofmore » whether that event was directly influenced by anthropogenic forcing of the climate system.« less

  3. 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.

  4. 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

  5. The 2015 Oklahoma extreme precipitation: attribution of climate change

    NASA Astrophysics Data System (ADS)

    Nie, J.; Sobel, A. H.; Shaevitz, D.

    2016-12-01

    In a warming climate precipitation extremes increase disproportionally faster than the mean precipitation does. However, there are large uncertainties of the paces of the precipitation extreme increases among General Circulation Models (GCMs) in the tropics and subtropics, largely due to the deficiencies of convective parameterizations. A hierarchy of models, including regional models and cloud resolving models (CRM) with high resolutions to explicitly resolve convection, can provide insights to better constrain the GCM simulations. In this study, we apply a novel CRM modeling approach, the Column Quasi-Geostrophic (CQG) method, to examine responses of precipitation extreme to climate changes. The CQG approach uses a CRM in a relatively small domain with the large-scale vertical motion, which determines vertical advection of temperature and moisture, incorporated using the quasi-geostrophic omega equation. Comparing with other CRM studies that prescribe the large-scale vertical motion, this method allows us to examine the dynamical component of precipitation increases (, to which the GCMs largely disagree with each other) to warming in addition to the thermodynamical component of increases (about 7% per K). We model the 2015 Oklahoma extreme rainfall event with CQG method, with the present climate and two counterfactual environments representing the pre-industry and an even warmer climate. Results are analyzed to attribute the extreme precipitation to climate changes, and to quantify the involved mechanisms.

  6. The role of climate variability in extreme floods in Europe

    NASA Astrophysics Data System (ADS)

    Guimarães Nobre, G.; Jongman, B.; Aerts, J.; Ward, P. J.

    2017-08-01

    Climate variability is shown to be an important driver of spatial and temporal changes in hydrometereological variables in Europe. However, the influence of climate variability on flood damage has received little attention. We investigated the El Niño Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), and the East Atlantic pattern (EA) during their neutral, positive, and negative phases, to understand their relationships with four flood indicators: Occurrence of Extreme Rainfall, Intensity of Extreme Rainfall, Flood Occurrence, and Flood Damage. We found that positive and negative phases of NAO and EA are associated with more (or less) frequent and intense seasonal extreme rainfall over large areas of Europe. The relationship between ENSO and the Occurrence of Extreme Rainfall and Intensity of Extreme Rainfall in Europe is much smaller than the relationship with NAO or EA, but still significant in some regions. We show that Flood Damage and Flood Occurrence have strong links with climate variability, especially in southern and eastern Europe. Therefore, when investigating flooding across Europe, all three indices of climate variability should be considered. Future research should focus on their joint influence on flood risk. The potential inclusion of seasonal forecasts of indices of climate variability could be effective in forecasting flood damage.

  7. Propagation of precipitation extremes into discharge extremes in a changing climate

    NASA Astrophysics Data System (ADS)

    Piras, Monica; Mascaro, Giuseppe; Deidda, Roberto; Vivoni, Enrique R.

    2015-04-01

    Mediterranean basins are characterized by high precipitation variability, which presents strong seasonality, large inter-annual fluctuations and spatial variations during single events, and by wide spatial differences of terrain and surface properties. As a consequence, these catchments are often prone to the occurrence of hydro-meteorological extremes, including storms, floods and flash-floods. Several climate projections in this area predict a general exacerbation of intensity and frequency of extreme events, thus requiring further analyses to evaluate their impact at the land surface, especially in relatively small watersheds. In this study, we used climate and hydrologic simulations produced within the Climate Induced Changes on the Hydrology of Mediterranean Basins (CLIMB) research project to analyze how precipitation extremes propagate into discharge extremes under changing climate conditions in the Rio Mannu basin (472.5 km2), an agricultural watershed located in Sardinia, Italy. The basin response to climate forcings in a reference (1971-2000; REF) and a future (2041-2070; FUT) period was simulated by using four combinations of global and regional climate models (CMs), statistical downscaling techniques, and a process based distributed hydrologic model. We first conducted statistical analyses based on the General Extreme Value (GEV) distribution on precipitation annual maxima at different durations (daily and hourly), extracted from the grids of the four selected CMs. Results show high uncertainties in climate projections, with GEV parameters differing among CMs, REF and FUT periods, and time duration. Subsequently, we fitted the GEV distribution to the series of maximum annual discharge data at daily and hourly duration, simulated by the hydrologic model at distributed basin locations. The analyses reveal that sub-basins characterized by lower slope and dominated by more impermeable soils have higher probabilities of extreme event occurrence than steeper

  8. Changing step width alters lower extremity biomechanics during running.

    PubMed

    Brindle, Richard A; Milner, Clare E; Zhang, Songning; Fitzhugh, Eugene C

    2014-01-01

    Step width is a spatiotemporal parameter that may influence lower extremity biomechanics at the hip and knee joint. The purpose of this study was to determine the biomechanical response of the lower extremity joints to step width changes during running. Lower extremity data from 30 healthy runners, half of them male, were collected during running in three step width conditions: preferred, wide, and narrow. Dependent variables and step width were analyzed using a mixed model ANOVA and pairwise t-tests for post hoc comparisons. Step width was successfully altered in the wide and narrow conditions. Generally, frontal plane peak values decreased as step width increased from narrow to preferred to wide. Peak hip adduction and rearfoot eversion angles decreased as step width increased from narrow to wide. Peak knee abduction moment and knee abduction impulse also decreased as step width increased from narrow to wide. Although men and women ran differently, gender only influenced the effect of step width on peak rearfoot inversion moment. In conclusion, step width influences lower extremity biomechanics in healthy runners. When step width increased from narrow to wide, peak values of frontal plane variables decreased. In addition to previously reported changes at the rearfoot, the hip and knee joint biomechanics were also influenced by changes in step width.

  9. Evaluating wind extremes in CMIP5 climate models

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    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.

  10. 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.

  11. 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.

  12. 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

  13. The Extreme Climate Index: a novel and multi-hazard index for extreme weather events.

    NASA Astrophysics Data System (ADS)

    Cucchi, Marco; Petitta, Marcello; Calmanti, Sandro

    2017-04-01

    In this presentation we introduce the Extreme Climate Index (ECI): an objective, multi-hazard index capable of tracking changes in the frequency or magnitude of extreme weather events in African countries, thus indicating that a shift to a new climate regime is underway in a particular area. This index has been developed in the context of XCF (eXtreme Climate Facilities) project lead by ARC (African Risk Capacity, specialised agency of the African Union), and will be used in the payouts triggering mechanism of an insurance programme against risks related to the increase of frequency and magnitude of extreme weather events due to climate regimes' changes. The main hazards covered by ECI will be extreme dry, wet and heat events, with the possibility of adding region-specific risk events such as tropical cyclones for the most vulnerable areas. It will be based on data coming from consistent, sufficiently long, high quality historical records and will be standardized across broad geographical regions, so that extreme events occurring under different climatic regimes in Africa can be comparable. The first step to construct such an index is to define single hazard indicators. In this first study we focused on extreme dry/wet and heat events, using for their description respectively the well-known SPI (Standardized Precipitation Index) and an index developed by us, called SHI (Standardized Heat-waves Index). The second step consists in the development of a computational strategy to combine these, and possibly other indices, so that the ECI can describe, by means of a single indicator, different types of climatic extremes. According to the methodology proposed in this paper, the ECI is defined by two statistical components: the ECI intensity, which indicates whether an event is extreme or not; the angular component, which represent the contribution of each hazard to the overall intensity of the index. The ECI can thus be used to identify "extremes" after defining a

  14. Perspectives on Extremes as a Climate Scientist and Farmer

    NASA Astrophysics Data System (ADS)

    Grotjahn, R.

    2016-12-01

    The speaker is both a climate scientist whose research emphasizes climate extremes and a small farmer in the most agriculturally productive region in the world. He will share some perspectives about the future of extremes over the United States as they relate to farming. General information will be drawn from the National Climate Assessment (NCA) published in 2014. Different weather-related quantities are useful for different commodities. While plant and animal production are time-integrative, extreme events can cause lasting harm long after the event is over. Animal production, including dairy, is sensitive to combinations of high heat and humidity; lasting impacts include suspended milk production, aborted fetuses, and increased mortality. The rice crop can be devastated by the wrong combination of wind and humidity just before harvest time. Extremes at the bud break, flowering, and nascent fruit stage and greatly reduce the fruit production for the year in tree crops. Saturated soils from heavy rainfall cause major losses to some crops (for example, by fostering pathogen growth), harm water delivery systems, and disrupt timing of field activities (primarily harvest).After an overview of some general issues relating to Agriculture, some extreme weather impacts on specific commodities (primarily dairy and specialty crops, some grains) will be highlighted including quantities relevant to agriculture. Example extreme events economic impacts will be summarized. If there is interest, issues related to water availability and management will be described. Projected extreme event changes over the US will be discussed. Some conclusions will be drawn about: future impacts and possible changes to farming (some are already occurring). Perspectives will be given on including the diverse range of quantities useful to agriculture when developing climate models. As time permits, some personal experiences with climate change and discussing it with fellow farmers will be shared.

  15. 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.

  16. 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.

  17. Genetic and life-history consequences of extreme climate events.

    PubMed

    Vincenzi, Simone; Mangel, Marc; Jesensek, Dusan; Garza, John Carlos; Crivelli, Alain J

    2017-02-08

    Climate change is predicted to increase the frequency and intensity of extreme climate events. Tests on empirical data of theory-based predictions on the consequences of extreme climate events are thus necessary to understand the adaptive potential of species and the overarching risks associated with all aspects of climate change. We tested predictions on the genetic and life-history consequences of extreme climate events in two populations of marble trout Salmo marmoratus that have experienced severe demographic bottlenecks due to flash floods. We combined long-term field and genotyping data with pedigree reconstruction in a theory-based framework. Our results show that after flash floods, reproduction occurred at a younger age in one population. In both populations, we found the highest reproductive variance in the first cohort born after the floods due to a combination of fewer parents and higher early survival of offspring. A small number of parents allowed for demographic recovery after the floods, but the genetic bottleneck further reduced genetic diversity in both populations. Our results also elucidate some of the mechanisms responsible for a greater prevalence of faster life histories after the extreme event. © 2017 The Author(s).

  18. Statistical methods for the analysis of climate extremes

    NASA Astrophysics Data System (ADS)

    Naveau, Philippe; Nogaj, Marta; Ammann, Caspar; Yiou, Pascal; Cooley, Daniel; Jomelli, Vincent

    2005-08-01

    Currently there is an increasing research activity in the area of climate extremes because they represent a key manifestation of non-linear systems and an enormous impact on economic and social human activities. Our understanding of the mean behavior of climate and its 'normal' variability has been improving significantly during the last decades. In comparison, climate extreme events have been hard to study and even harder to predict because they are, by definition, rare and obey different statistical laws than averages. In this context, the motivation for this paper is twofold. Firstly, we recall the basic principles of Extreme Value Theory that is used on a regular basis in finance and hydrology, but it still does not have the same success in climate studies. More precisely, the theoretical distributions of maxima and large peaks are recalled. The parameters of such distributions are estimated with the maximum likelihood estimation procedure that offers the flexibility to take into account explanatory variables in our analysis. Secondly, we detail three case-studies to show that this theory can provide a solid statistical foundation, specially when assessing the uncertainty associated with extreme events in a wide range of applications linked to the study of our climate. To cite this article: P. Naveau et al., C. R. Geoscience 337 (2005).

  19. 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.

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

    NASA Astrophysics Data System (ADS)

    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

    2015-10-01

    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.

  1. 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.

  2. Impacts of Amazon deforestation on regional weather and climate extremes

    NASA Astrophysics Data System (ADS)

    Medvigy, D.; Walko, R. L.; Avissar, R.

    2010-12-01

    Recent deforestation projections estimate that 40% of the Amazon rainforest will be deforested by 2050. Many modeling studies have indicated that deforestation will reduce average rainfall in the Amazon. However, very few studies have investigated the potential for deforestation to change the frequency and intensity of extreme climate and weather events. To fill this gap in our understanding, we use a variable-resolution GCM to investigate how precipitation and temperature extremes throughout South America respond to deforestation. The model’s grid mesh is set up to cover South America and nearby oceans at mesoscale (25 km) resolution, and then to gradually coarsen and cover the rest of the world at 200 km resolution. This approach differs from the two most common current approaches: (1) to use a GCM with too coarse of a resolution to evaluate regional climate extremes, or (2) to use a regional atmospheric model that requires lateral boundary conditions from a GCM or reanalysis. We find that deforestation induces large changes in winter (June-July-August) climate throughout much of South America. Extreme cold events become much more common along the eastern slopes of the Andes. The largest changes were in the western Amazon and, surprisingly, in Argentina, far from the actual deforested area. We also find shifts in precipitation extremes, especially in September-October-November. Such changes in temperature and precipitation extremes have important consequences for agriculture, natural ecosystems, and human society.

  3. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Variable effects of climate on forest growth in relation to climate extremes, disturbance, and forest dynamics.

    PubMed

    Itter, Malcolm S; Finley, Andrew O; D'Amato, Anthony W; Foster, Jane R; Bradford, John B

    2017-06-01

    Changes in the frequency, duration, and severity of climate extremes are forecast to occur under global climate change. The impacts of climate extremes on forest productivity and health remain difficult to predict due to potential interactions with disturbance events and forest dynamics-changes in forest stand composition, density, size and age structure over time. Such interactions may lead to non-linear forest growth responses to climate involving thresholds and lag effects. Understanding how forest dynamics influence growth responses to climate is particularly important given stand structure and composition can be modified through management to increase forest resistance and resilience to climate change. To inform such adaptive management, we develop a hierarchical Bayesian state space model in which climate effects on tree growth are allowed to vary over time and in relation to past climate extremes, disturbance events, and forest dynamics. The model is an important step toward integrating disturbance and forest dynamics into predictions of forest growth responses to climate extremes. We apply the model to a dendrochronology data set from forest stands of varying composition, structure, and development stage in northeastern Minnesota that have experienced extreme climate years and forest tent caterpillar defoliation events. Mean forest growth was most sensitive to water balance variables representing climatic water deficit. Forest growth responses to water deficit were partitioned into responses driven by climatic threshold exceedances and interactions with insect defoliation. Forest growth was both resistant and resilient to climate extremes with the majority of forest growth responses occurring after multiple climatic threshold exceedances across seasons and years. Interactions between climate and disturbance were observed in a subset of years with insect defoliation increasing forest growth sensitivity to water availability. Forest growth was particularly

  5. Variable effects of climate on forest growth in relation to climate extremes, disturbance, and forest dynamics

    USGS Publications Warehouse

    Itter, Malcolm S.; Finley, Andrew O.; D'Amato, Anthony W.; Foster, Jane R.; Bradford, John B.

    2017-01-01

    Changes in the frequency, duration, and severity of climate extremes are forecast to occur under global climate change. The impacts of climate extremes on forest productivity and health remain difficult to predict due to potential interactions with disturbance events and forest dynamics—changes in forest stand composition, density, size and age structure over time. Such interactions may lead to non-linear forest growth responses to climate involving thresholds and lag effects. Understanding how forest dynamics influence growth responses to climate is particularly important given stand structure and composition can be modified through management to increase forest resistance and resilience to climate change. To inform such adaptive management, we develop a hierarchical Bayesian state space model in which climate effects on tree growth are allowed to vary over time and in relation to past climate extremes, disturbance events, and forest dynamics. The model is an important step toward integrating disturbance and forest dynamics into predictions of forest growth responses to climate extremes. We apply the model to a dendrochronology data set from forest stands of varying composition, structure, and development stage in northeastern Minnesota that have experienced extreme climate years and forest tent caterpillar defoliation events. Mean forest growth was most sensitive to water balance variables representing climatic water deficit. Forest growth responses to water deficit were partitioned into responses driven by climatic threshold exceedances and interactions with insect defoliation. Forest growth was both resistant and resilient to climate extremes with the majority of forest growth responses occurring after multiple climatic threshold exceedances across seasons and years. Interactions between climate and disturbance were observed in a subset of years with insect defoliation increasing forest growth sensitivity to water availability. Forest growth was particularly

  6. 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

  7. 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.

  8. 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.

  9. Climatic Alterations of Wetlands: Conservation and Adaptation Practices in Bangladesh

    NASA Astrophysics Data System (ADS)

    Siddiquee, S. A.

    2016-02-01

    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.

  10. 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. ...

  11. 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.

  12. Recent Extremes in European Climate: Assessment, Case Studies and Impacts

    NASA Astrophysics Data System (ADS)

    Yiou, P.; Vautard, R.; D'Andrea, F.; Cattiaux, J.; Naveau, P.; Ciais, P.; Garnier, E.

    2008-12-01

    During the last centuries and up to the present decade, extreme climate events have certainly had larger economic impacts than any trend of temperature in Europe. In addition to an intrinsic scientific interest, their study is thus essential for society. One of the challenges of their investigation is that, depending on their definition, extreme climate events potentially have a behavior that is not connected to the secular temperature trend in a simple fashion. This presentation will review the statistical assessments of extremes in Europe, focusing on surface temperature, precipitation, and their connections with large-scale features of the atmospheric circulation. In particular, the questions of modeling their severity and frequency will be discussed in the first part of the presentation. I will then give two kinds of examples of European climate extremes: summer heatwaves and droughts, and winter warm waves. The mechanisms leading to such phenomena will be explored, and I will examine some of the impacts on the biosphere that were recently observed. In order to provide a long term perspective of those events, examples of historical droughts in France will be presented and connected with proxy records of temperature. It appears that the mechanisms that are favored for present-day climate might still have been valid during the past centuries. To conclude, new challenges for dynamical and statistical modeling will be explored.

  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. EURO4M: monitoring weather and climate extremes in Europe

    NASA Astrophysics Data System (ADS)

    Klein Tank, A. M. G.

    2010-09-01

    This paper presents a new project called EURO4M: European Reanalysis and Observations for Monitoring (www.euro4m.eu), which is funded under the European Union FP7 programme. The ambitious plans in this project will be illustrated by examples from ongoing work and some early results. EURO4M sets out to develop the capacity for, and deliver the best possible and most complete (gridded) climate change time series and monitoring services covering all of Europe. The focus is on weather and climate extremes. Key questions include: What changes in weather and climate extremes do we observe in Europe over recent decades? How certain are we about these changes? Are our monitoring systems adequate to address these questions? EURO4M addresses the situation of fragmentation and scarcity of long-term climate change monitoring information for Europe. The project will extend, in a cost effective manner, European capacity to systematically monitor climate variability and change on a range of space and time scales. It will do so by combining seamlessly two different but complementary approaches: regional observation datasets of GCOS Essential Climate Variables (ECVs) and newly developed regional reanalysis. EURO4M will reach out with innovative and integrated data products and services to policy-makers, researchers, planners and citizens at European, national and local levels. This will directly address the needs of, for instance, the European Environment Agency for their environmental assessment reports - and even provide online reporting during emerging extreme events. EURO4M intends to become Europe's primary source of timely and reliable information about the state of the climate. The project has the potential to evolve into a future GMES service on climate change monitoring that is fully complimentary and supporting the existing operational GMES services. The EURO4M consortium consists of 9 partners from 8 countries. The project will run from 1 April 2010 until 31 March 2014

  15. Impact of an extreme climatic event on community assembly

    PubMed Central

    Thibault, Katherine M.; Brown, James H.

    2008-01-01

    Extreme climatic events are predicted to increase in frequency and magnitude, but their ecological impacts are poorly understood. Such events are large, infrequent, stochastic perturbations that can change the outcome of entrained ecological processes. Here we show how an extreme flood event affected a desert rodent community that has been monitored for 30 years. The flood (i) caused catastrophic, species-specific mortality; (ii) eliminated the incumbency advantage of previously dominant species; (iii) reset long-term population and community trends; (iv) interacted with competitive and metapopulation dynamics; and (v) resulted in rapid, wholesale reorganization of the community. This and a previous extreme rainfall event were punctuational perturbations—they caused large, rapid population- and community-level changes that were superimposed on a background of more gradual trends driven by climate and vegetation change. Captured by chance through long-term monitoring, the impacts of such large, infrequent events provide unique insights into the processes that structure ecological communities. PMID:18303115

  16. Impact of an extreme climatic event on community assembly.

    PubMed

    Thibault, Katherine M; Brown, James H

    2008-03-04

    Extreme climatic events are predicted to increase in frequency and magnitude, but their ecological impacts are poorly understood. Such events are large, infrequent, stochastic perturbations that can change the outcome of entrained ecological processes. Here we show how an extreme flood event affected a desert rodent community that has been monitored for 30 years. The flood (i) caused catastrophic, species-specific mortality; (ii) eliminated the incumbency advantage of previously dominant species; (iii) reset long-term population and community trends; (iv) interacted with competitive and metapopulation dynamics; and (v) resulted in rapid, wholesale reorganization of the community. This and a previous extreme rainfall event were punctuational perturbations-they caused large, rapid population- and community-level changes that were superimposed on a background of more gradual trends driven by climate and vegetation change. Captured by chance through long-term monitoring, the impacts of such large, infrequent events provide unique insights into the processes that structure ecological communities.

  17. Mid-Latitude Circulation and Extremes in a Changing Climate

    SciTech Connect

    Chen, Gang

    2016-08-04

    Mid-latitude extreme weather events are responsible for a large part of climate-related damage. Yet large uncertainties remain in climate model projections of heat waves, droughts, and heavy rain/snow events on regional scales, limiting our ability to effectively use these projections for climate adaptation and mitigation. These uncertainties can be attributed to both the lack of spatial resolution in the models, and to the lack of a dynamical understanding of these extremes. The approach of this project is to relate the fine-scale features to the large scales in current climate simulations, seasonal re-forecasts, and climate change projections in a very wide range of models, including the atmospheric and coupled models of ECMWF over a range of horizontal resolutions (125 to 10 km), aqua-planet configuration of the Model for Prediction Across Scales and High Order Method Modeling Environments (resolutions ranging from 240 km – 7.5 km) with various physics suites, and selected CMIP5 model simulations. The large scale circulation will be quantified both on the basis of the well tested preferred circulation regime approach, and very recently developed measures, the finite amplitude Wave Activity (FAWA) and its spectrum. The fine scale structures related to extremes will be diagnosed following the latest approaches in the literature. The goal is to use the large scale measures as indicators of the probability of occurrence of the finer scale structures, and hence extreme events. These indicators will then be applied to the CMIP5 models and time-slice projections of a future climate.

  18. Compound extremes in a changing climate - a Markov chain approach

    NASA Astrophysics Data System (ADS)

    Sedlmeier, Katrin; Mieruch, Sebastian; Schädler, Gerd; Kottmeier, Christoph

    2016-11-01

    Studies using climate models and observed trends indicate that extreme weather has changed and may continue to change in the future. The potential impact of extreme events such as heat waves or droughts depends not only on their number of occurrences but also on "how these extremes occur", i.e., the interplay and succession of the events. These quantities are quite unexplored, for past changes as well as for future changes and call for sophisticated methods of analysis. To address this issue, we use Markov chains for the analysis of the dynamics and succession of multivariate or compound extreme events. We apply the method to observational data (1951-2010) and an ensemble of regional climate simulations for central Europe (1971-2000, 2021-2050) for two types of compound extremes, heavy precipitation and cold in winter and hot and dry days in summer. We identify three regions in Europe, which turned out to be likely susceptible to a future change in the succession of heavy precipitation and cold in winter, including a region in southwestern France, northern Germany and in Russia around Moscow. A change in the succession of hot and dry days in summer can be expected for regions in Spain and Bulgaria. The susceptibility to a dynamic change of hot and dry extremes in the Russian region will probably decrease.

  19. Extreme developmental temperatures result in morphological abnormalities in painted turtles (Chrysemys picta): a climate change perspective.

    PubMed

    Telemeco, Rory S; Warner, Daniel A; Reida, Molly K; Janzen, Fredric J

    2013-06-01

    Increases in extreme environmental events are predicted to be major results of ongoing global climate change and may impact the persistence of species. We examined the effects of heat and cold waves during embryonic development of painted turtles (Chrysemys picta) in natural nests on the occurrence of abnormal shell morphologies in hatchlings. We found that nests exposed to extreme hot temperatures for >60 h produced more hatchlings with abnormalities than nests exposed to extreme hot temperatures for shorter periods, regardless of whether or not nesting females displayed abnormal morphologies. We observed no effect of extreme cold nest temperatures on the occurrence of hatchlings with abnormalities. Moreover, the frequency of nesting females with abnormal shell morphologies was approximately 2-fold lower than that of their offspring, suggesting that such abnormalities are negatively correlated with survival and fitness. Female turtles could potentially buffer their offspring from extreme heat by altering aspects of nesting behavior, such as choosing shadier nesting sites. We addressed this hypothesis by examining the effects of shade cover on extreme nest temperatures and the occurrence of hatchling abnormalities. While shade cover was negatively correlated with the occurrence of extreme hot nest temperatures, it was not significantly correlated with abnormalities. Therefore, female choice of shade cover does not appear to be a viable target for selection to reduce hatchling abnormalities. Our results suggest that increases in the frequency and intensity of heat waves associated with climate change might perturb developmental programs and thereby reduce the fitness of entire cohorts of turtles.

  20. Abrupt shifts in phenology and vegetation productivity under climate extremes

    NASA Astrophysics Data System (ADS)

    Ma, Xuanlong; Huete, Alfredo; Moran, Susan; Ponce-Campos, Guillermo; Eamus, Derek

    2015-10-01

    Amplification of the hydrologic cycle as a consequence of global warming is predicted to increase climate variability and the frequency and severity of droughts. Recent large-scale drought and flooding over numerous continents provide unique opportunities to understand ecosystem responses to climatic extremes. In this study, we investigated the impacts of the early 21st century extreme hydroclimatic variations in southeastern Australia on phenology and vegetation productivity using Moderate Resolution Imaging Spectroradiometer Enhanced Vegetation Index and Standardized Precipitation-Evapotranspiration Index. Results revealed dramatic impacts of drought and wet extremes on vegetation dynamics, with abrupt between year changes in phenology. Drought resulted in widespread reductions or collapse in the normal patterns of seasonality such that in many cases there was no detectable phenological cycle during drought years. Across the full range of biomes examined, we found semiarid ecosystems to exhibit the largest sensitivity to hydroclimatic variations, exceeding that of arid and humid ecosystems. This result demonstrated the vulnerability of semiarid ecosystems to climatic extremes and potential loss of ecosystem resilience with future mega-drought events. A skewed distribution of hydroclimatic sensitivity with aridity is of global biogeochemical significance because it suggests that current drying trends in semiarid regions will reduce hydroclimatic sensitivity and suppress the large carbon sink that has been reported during recent wet periods (e.g., 2011 La Niña).

  1. Extreme Precipitation and Runoff under Changing Climate in Southern Maine

    SciTech Connect

    Yan, Eugene; Jared, Alissa; Mahat, Vinod; Picel, Mark; Verner, Duane; Wall, Thomas; Moges, Edom M.; Demissie, Yonas K.; Pierce, Julia

    2016-12-01

    The quantification of extreme precipitation events is vitally important for designing and engineering water and flood sensitive infrastructure. Since this kind of infrastructure is usually built to last much longer than 10, 50, or even 100 years, there is great need for statistically sound estimates of the intensity of 10-, 50-, 100-, and 500-year rainstorms and associated floods. The recent assessment indicated that the intensity of the most extreme precipitation events (or the heaviest 1% of all daily events) have increased in every region of the contiguous states since the 1950s (Melillo et al. 2014). The maximum change in precipitation intensity of extreme events occurred in the northeast region reaching 71%. The precipitation extremes can be characterized using intensity-duration-frequency analysis (IDF). However, the current IDFs in this region were developed around the assumption that climate condition remains stationary over the next 50 or 100 years. To better characterize the potential flood risk, this project will (1) develop precipitation IDFs on the basis of both historical observations and future climate projections from dynamic downscaling with Argonne National Laboratory’s (Argonne’s) regional climate model and (2) develop runoff IDFs using precipitation IDFs for the Casco Bay Watershed. IDF development also considers non-stationary distribution models and snowmelt effects that are not incorporated in the current IDFs.

  2. Ecosystem recovery after climatic extremes enhanced by genotypic diversity

    PubMed Central

    Reusch, Thorsten B. H.; Ehlers, Anneli; Hämmerli, August; Worm, Boris

    2005-01-01

    Contemporary climate change is characterized both by increasing mean temperature and increasing climate variability such as heat waves, storms, and floods. How populations and communities cope with such climatic extremes is a question central to contemporary ecology and biodiversity conservation. Previous work has shown that species diversity can affect ecosystem functioning and resilience. Here, we show that genotypic diversity can replace the role of species diversity in a species-poor coastal ecosystem, and it may buffer against extreme climatic events. In a manipulative field experiment, increasing the genotypic diversity of the cosmopolitan seagrass Zostera marina enhanced biomass production, plant density, and faunal abundance, despite near-lethal water temperatures due to extreme warming across Europe. Net biodiversity effects were explained by genotypic complementarity rather than by selection of particularly robust genotypes. Positive effects on invertebrate fauna suggest that genetic diversity has second-order effects reaching higher trophic levels. Our results highlight the importance of maintaining genetic as well as species diversity to enhance ecosystem resilience in a world of increasing uncertainty. PMID:15710890

  3. 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

  4. Extreme weather events in Iran under a changing climate

    NASA Astrophysics Data System (ADS)

    Alizadeh-Choobari, Omid; Najafi, M. S.

    2017-03-01

    Observations unequivocally show that Iran has been rapidly warming over recent decades, which in sequence has triggered a wide range of climatic impacts. Meteorological records of several ground stations across Iran with daily temporal resolution for the period 1951-2013 were analyzed to investigate the climate change and its impact on some weather extremes. Iran has warmed by nearly 1.3° C during the period 1951-2013 (+0.2° per decade), with an increase of the minimum temperature at a rate two times that of the maximum. Consequently, an increase in the frequency of heat extremes and a decrease in the frequency of cold extremes have been observed. The annual precipitation has decreased by 8 mm per decade, causing an expansion of Iran's dry zones. Previous studies have pointed out that warming is generally associated with more frequent heavy precipitation because a warmer air can hold more moisture. Nevertheless, warming in Iran has been associated with more frequent light precipitation, but less frequent moderate, heavy and extremely heavy precipitation. This is because in the subtropical dry zones, a longer time is required to recharge the atmosphere with water vapour in a warmer climate, causing more water vapour to be transported from the subtropics to high latitudes before precipitations forms. In addition, the altitude of the condensation level increases in a warmer climate in subtropical regions, causing an overall decrease of precipitation. We argue that changing in the frequency of heavy precipitation in response to warming varies depending on the geographical location. Warming over the dry subtropical regions is associated with a decrease in the frequency of heavy precipitation, while an increase is expected over both subpolar and tropical regions. The warmer climate has also led to the increase in the frequency of both thunderstorms (driven by convective heating) and dust events over Iran.

  5. 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.

  6. 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.

  7. Influence of the North Atlantic on European climate extremes

    NASA Astrophysics Data System (ADS)

    Prömmel, Kerstin; Cubasch, Ulrich

    2017-04-01

    With the help of simulations performed with the Max Plank Institute for Meteorology Earth System Model (MPI-ESM) we try to understand the processes and mechanisms leading to European climate extremes. These extremes include for example cold, warm or snowy winters. For the analysis of the underlying mechanisms we concentrate on modes like the North Atlantic Oscillation (NAO) and the Atlantic Multi-decadal Variability (AMV), which are supposed to influence each other. The NAO has a strong impact especially on European winter and the changes in minimum temperature are even larger than in maximum temperature. The influence of the spatial resolution of MPI-ESM on the results is also investigated.

  8. 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

  9. 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.

  10. Spatio-temporal dynamics of climatic extreme indices over Siberia

    NASA Astrophysics Data System (ADS)

    Shulgina, Tamara; Gordov, Evgeny; Genina, Elena

    2013-04-01

    Nowadays numerous investigations are aimed at analysis of regional climatic extremes becoming more pronounced under climate change. In particular, obtained results indicate decrease of number of frost days and increase of growing season length over the most part of Siberian territory, and precipitation intensity increases in the northern part of Siberia [1]. To obtain the complete pattern of ongoing changes in climatic extremes the following indices dynamics should be analyzed: percentage of days when minimum/maximum temperature less than 10th percentile, percentage of days minimum/maximum temperature greater than 90th percentile, maximum length of dry/wet spell. Climatic extreme assessments are obtained based on ECMWF ERA Interim Reanalysis and APHRODITE JMA data for the time period from 1979 to 2007. These datasets reproduce the statistics of observed climate features in Siberia more accurately [1]. Modern techniques of mathematical statistics are used for analysis of the temporal and spatial behavior of above mentioned climatic characteristics. Data analysis has been done using computational-geoinformational web-system for analysis of regional climatic change [2]. Surface temperature and precipitation extreme assessments obtained for Siberian territory can help to get a better understanding of current changes in the biosphere and socio-economic aspects. Partial financial support for this research from the Russian Foundation for Basic Research (project 11-05-01190a), SB RAS projects VIII.80.2.1 and 131, and the Russian Federation Ministry of Education and Science grant # 8345 is acknowledged. 1. Shulgina T.M., Genina E.Yu., Gordov E.P. Dynamics of climatic characteristics influencing vegetation in Siberia // Environmental Research Letters, 2011. - DOI: 10.1088/1748-9326/6/4/045210. - 7 p. 2. Evgeny Gordov et al. Development of Information-Computational Infrastructure for Environmental research in Siberia as a baseline component of the Northern Eurasia Earth

  11. Temperature extremes in a changing climate: Drivers and feedbacks (Invited)

    NASA Astrophysics Data System (ADS)

    Seneviratne, S. I.; Davin, E. L.; Hirschi, M.; Mueller, B.; Orlowsky, B.; Orth, R.; Wilhelm, M.

    2013-12-01

    Global warming increases the occurrence probability of hot extremes, and improving the predictability of such events is thus becoming of critical importance (e.g. Seneviratne et al. 2012). This presentation provides an overview of past and projected changes in hot extremes on the global and regional scale, and of the respective drivers and feedbacks responsible for their occurrence. In particular, soil moisture-temperature feedbacks have been identified as major drivers for hot extremes (e.g. Seneviratne et al. 2006, 2010; Hirschi et al. 2011). Recently, a global study (Mueller and Seneviratne 2012) has shown that wide areas of the world display a strong relationship between the number of hot days in the regions' hottest month and preceding precipitation deficits. These findings suggest that effects of soil moisture-temperature coupling are geographically more widespread than commonly assumed, with for instance large hot spots of soil moisture-temperature coupling in the Southern Hemisphere. Further results indicate that this relationship could be better used in the context of seasonal forecasting, allowing an early warning of impending hot summers (Mueller and Seneviratne 2012, Orth and Seneviratne 2013). In addition, the role of soil moisture-climate feedbacks for climate projections will also be discussed (e.g. Orlowsky and Seneviratne 2012; Seneviratne et al., 2013). Finally, we will address the relevance of the identified feedbacks in the context of urban climate, as well as potential relevant impacts of other land-climate interactions (e.g. from modifications in surface albedo). References: Hirschi, M., et al., 2011: Observational evidence for soil-moisture impact on hot extremes in southeastern Europe. Nature Geosci., 4, 17-21, doi:10.1038/ngeo1032. Mueller, B., and S.I. Seneviratne, 2012: Hot days induced by precipitation deficits at the global scale. Proc. Natl Acad. Sci., 109 (31), 12398-12403, doi: 10.1073/pnas.1204330109. Orth, R. and S.I. Seneviratne

  12. Altered lower extremity fracture characteristics in obese pediatric trauma patients.

    PubMed

    Gilbert, Shawn R; MacLennan, Paul A; Backstrom, Ian; Creek, Aaron; Sawyer, Jeffrey

    2015-01-01

    To determine whether there are differences in fracture patterns and femur fracture treatment choices in obese versus nonobese pediatric trauma patients. Prognostic study, retrospective chart review. Two level I pediatric trauma centers. The trauma registries of 2 pediatric hospitals were queried for patients with lower extremity long-bone fractures resulting from blunt trauma. 2858 alerts were examined, and 397 patients had lower extremity fractures. Three hundred thirty-one patients with a total of 394 femur or tibia fractures met the inclusion criteria, and 70 patients (21%) were obese. Weight for age >95th percentile was defined as obese. Radiographs were reviewed, and fractures were classified according the OTA/AO pediatric fracture classification system. Fracture patterns (OTA subsegment), severity, and choice of intervention for femur fractures were the primary outcomes. Overall, obese patients were twice as likely [risk ratio (RR), 2.20; 95% confidence interval (CI), 1.25-3.89] to have fractures involving the physis. Physeal fracture risk was greater for femur fractures (RR, 3.25; 95% CI, 1.35-7.78) than tibia fractures (RR, 1.58; 95% CI, 0.76-3.26). Severity did not differ between groups. Obese patients with femur fractures were more likely to be treated with locked nails. Obese pediatric trauma patients are more likely to sustain fractures involving the physis than nonobese patients. This could be related to intrinsic changes to the physis related to obesity or altered biomechanical forces. This is consistent with the observed relationships between obesity and other conditions affecting the physis including Blount disease and slipped capital femoral epiphysis. Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

  13. Altered lower extremity fracture characteristics in obese pediatric trauma patients

    PubMed Central

    MacLennan, Paul A.; Backstrom, Ian; Creek, Aaron; Sawyer, Jeffrey

    2014-01-01

    Objective To determine whether there are differences in fracture patterns and femur fracture treatment choices in obese vs. non-obese pediatric trauma patients. Design Prognostic study, retrospective chart review. Setting Two level I pediatric trauma centers. Patients The trauma registries of two pediatric hospitals were queried for patients with lower extremity long bone fractures resulting from blunt trauma. 2858 alerts were examined and 397 patients had lower extremity fractures. 331 patients with a total of 394 femur or tibia fractures met inclusion criteria, and 70 patients (21%) were obese. Main Outcome Measurements Weight for age >95th percentile was defined as obese. Radiographs were reviewed and fractures were classified according the OTA/AO pediatric fracture classification system. Fracture patterns (OTA subsegment), severity, and choice of intervention for femur fractures were primary outcomes. Results Overall, obese patients were twice as likely (RR=2.20, 95% CI 1.25–3.89) to have fractures involving the physis. Physeal fracture risk was greater for femur fractures (RR=3.25, 95% CI 1.35–7.78) than tibia fractures (RR=1.58, 95% CI 0.76–3.26). Severity did not differ between groups. Obese patients with femur fractures were more likely to be treated with locked nails. Conclusion Obese pediatric trauma patients are more likely to sustain fractures involving the physis than non-obese patients. This could be related to intrinsic changes to the physis related to obesity, or altered biomechanical forces. This is consistent with the observed relationships between obesity and other conditions affecting the physis including Blount’s and slipped capital femoral epiphysis. PMID:24740109

  14. Statistics of Extreme Events with Application to Climate

    DTIC Science & Technology

    1992-01-01

    costs associated with global warming will be measured in terms of changes in the frequency and intensity of extreme events such as droughts, floods...in climate studies or in discussions of greenhouse warming despite the obvious importance of large deviations from 1 the mean. The theory and...examining 33 7.60 Globa Averaged Temerture Range for Gaussian Distributi, Dew oin Tepertur 6.40 r5-0Sea Surface Temperature - 5.20 4.60 4,00

  15. Potential impacts to freshwater ecosystems caused by flow regime alteration under changing climate conditions in Taiwan

    NASA Astrophysics Data System (ADS)

    Suen, J.-P.

    2008-11-01

    Observed increases in the Earth's surface temperature bring with them associated changes in precipitation and atmospheric moisture that consequentially alter river flow regimes. This paper uses the Indicators of Hydrologic Alteration approach to examine climate-induced flow regime changes that can potentially affect freshwater ecosystems. Analyses of the annual extreme water conditions at 23 gauging stations throughout Taiwan reveal large alterations in recent years; extreme flood and drought events were more frequent in the period after 1991 than from 1961 1990, and the frequency and duration of the flood and drought events also show high fluctuation. Climate change forecasts suggest that such flow regime alterations are going to continue into the foreseeable future. Aquatic organisms not only feel the effects of anthropogenic damage to river systems, but they also face on-going threats of thermal and flow regime alterations associated with climate change. This paper calls attention to the issue, so that water resources managers can take precautionary measures that reduce the cumulative effects from anthropogenic influence and changing climate conditions.

  16. 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

  17. Early benefits of mitigation in risk of regional climate extremes

    NASA Astrophysics Data System (ADS)

    Ciavarella, Andrew; Stott, Peter; Lowe, Jason

    2017-04-01

    Large differences in climate outcomes are projected by the end of this century depending on whether greenhouse gas emissions continue to increase or are reduced sufficiently to limit total warming to below 2 °C (ref. ). However, it is generally thought that benefits of mitigation are hidden by internal climate variability until later in the century. Here we show that if the likelihood of extremely hot seasons is considered, the benefits of mitigation emerge more quickly than previously thought. It takes less than 20 years of emissions reductions in many regions for the likelihood of extreme seasonal warmth to reduce by more than half following initiation of mitigation. Additionally we show that the latest possible date at which the probability of extreme seasonal temperatures will be halved through emissions reductions consistent with the 2 °C target is in the 2040s. Exposure to climate risk is therefore reduced markedly and rapidly with substantial reductions of greenhouse gas emissions, demonstrating that the early mitigation needed to limit eventual warming below potentially dangerous levels benefits societies in the nearer term not just in the longer-term future.

  18. 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

  19. 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.

  20. Impact of climate extremes on wildlife plant flowering over Germany

    NASA Astrophysics Data System (ADS)

    Siegmund, J. F.; Wiedermann, M.; Donges, J. F.; Donner, R. V.

    2015-11-01

    Ongoing climate change is known to cause an increase in the frequency and amplitude of local temperature and precipitation extremes in many regions of the Earth. 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. 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.

  1. Using Atmospheric Circulation Patterns to Detect and Attribute Changes in the Risk of Extreme Climate Events

    NASA Astrophysics Data System (ADS)

    Diffenbaugh, N. S.; Horton, D. E.; Singh, D.; Swain, D. L.; Touma, D. E.; Mankin, J. S.

    2015-12-01

    Because of the high cost of extreme events and the growing evidence that global warming is likely to alter the statistical distribution of climate variables, detection and attribution of changes in the probability of extreme climate events has become a pressing topic for the scientific community, elected officials, and the public. While most of the emphasis has thus far focused on analyzing the climate variable of interest (most often temperature or precipitation, but also flooding and drought), there is an emerging emphasis on applying detection and attribution analysis techniques to the underlying physical causes of individual extreme events. This approach is promising in part because the underlying physical causes (such as atmospheric circulation patterns) can in some cases be more accurately represented in climate models than the more proximal climate variable (such as precipitation). In addition, and more scientifically critical, is the fact that the most extreme events result from a rare combination of interacting causes, often referred to as "ingredients". Rare events will therefore always have a strong influence of "natural" variability. Analyzing the underlying physical mechanisms can therefore help to test whether there have been changes in the probability of the constituent conditions of an individual event, or whether the co-occurrence of causal conditions cannot be distinguished from random chance. This presentation will review approaches to applying detection/attribution analysis to the underlying physical causes of extreme events (including both "thermodynamic" and "dynamic" causes), and provide a number of case studies, including the role of frequency of atmospheric circulation patterns in the probability of hot, cold, wet and dry events.

  2. Tools in Support of Planning for Weather and Climate Extremes

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    A major limitation to planning for weather and climate extremes is the lack of maintained and readily available tools that can provide robust and well-communicated predictions and advice on their impacts. The National Center for Atmospheric Research is facilitating a collaborative international program to develop and support such tools within its Capacity Center for Climate and Weather Extremes aimed at improving community resilience planning and reducing weather and climate impacts. A Global Risk, Resilience and Impacts Toolbox is in development and will provide: A portable web-based interface to process work requests from a variety of users and locations; A sophisticated framework that enables specialized community tools to access a comprehensive database (public and private) of geo-located hazard, vulnerability, exposure, and loss data; A community development toolkit that enables and encourages community tool developments geared towards specific user man­agement and planning needs, and A comprehensive community sup­port facilitated by NCAR utilizing tutorials and a help desk. A number of applications are in development, built off the latest climate science, and in collaboration with private industry and local and state governments. Example applications will be described, including a hurricane damage tool in collaboration with the reinsurance sector, and a weather management tool for the construction industry. These examples will serve as starting points to discuss the broader potential of the toolbox.

  3. Assessing, Modeling, and Monitoring the Impacts of Extreme Climate Events

    NASA Astrophysics Data System (ADS)

    Murnane, Richard J.; Diaz, Henry F.

    2006-01-01

    Extreme weather and climate events provide dramatic content for the news media, and the past few years have supplied plenty of material. The 2004 and 2005 Atlantic hurricane seasons were very active; the United States was struck repeatedly by landfalling major hurricanes. A five-year drought in the southwestern United States was punctuated in 2003 by wildfires in southern California that caused billions of dollars in losses. Ten cyclones of at least tropical storm strength struck Japan in 2004, easily breaking the 1990 and 1993 records of six cyclones each year. Hurricane Catarina was the first recorded hurricane in the South Atlantic. Europe's summer of 2003 saw record-breaking heat that caused tens of thousands of deaths. These events have all been widely publicized, and they naturally raise several questions: Is climate changing, and if so, why? What can we expect in the future? How can we better respond to climate variability regardless of its source?

  4. 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.

  5. Recent droughts and effect of climate change on climate extremes in the East African region.

    NASA Astrophysics Data System (ADS)

    Mekonnen, Z. T.; Gebremichael, M.

    2016-12-01

    East Africa is a region that has been affected by droughts, floods, famine one too many times. 2015 was one of the worst droughts in the region in decades and created a food crisis in the region leading to 15 million people needing food and water assistance. In a region where the climate resilience of the society is low, understanding of the climate and how it's changing is very important. Unfortunately, only a few studies have been done in this area. In this study we looked at the recent droughts in the region and analyzed the trends in relation to historical data. A combination of remote sensing products like TRMM, GPM and MERRA were used in conjunction with gridded observed products like CPC as well as gauge observations to carry out the analysis. The second part of the analysis focused on how climate change will affect the climate extremes in the region focusing on precipitation, temperature and evapotranspiration. 20 selected GCMs from CMIP5 were used at a daily timescale to look at climate extremes. Changes in daily intensity of precipitation, seasonal shifts and total rainfall were analyzed for mid-century and end of the century RCP 6.0 scenario and compared to the historical figures. In addition, daily extreme temperature and evapotranspiration as well seasonal shifts were focuses of this study. Spatial variations were also shown to be important in understanding the changes. Even though studies have shown the total rainfall in the region didn't show a significant change in that region under climate change, seasonal shifts, extreme precipitation, extreme temperatures, prolonged droughts, and increase in evapotranspiration were observed in East Africa. In a region where population is expected to double by mid-century this extreme can put the lives of millions in danger. This study will be followed with another focusing on how these changes in extremes and distribution will affect the water resources in the region specifically the Nile.

  6. 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

  7. 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.

  8. 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.

  9. Potential impacts of land-use on climate variability and extremes

    NASA Astrophysics Data System (ADS)

    Zhang, Huqiang; Li, Yaohui; Gao, Xuejie

    2009-09-01

    This study aims at exploring potential impacts of land-use vegetation change (LUC) on regional climate variability and extremes. Results from a pair of Australian Bureau of Meteorology Research Centre (BMRC) climate model 54-yr (1949-2002) integrations have been analysed. In the model experiments, two vegetation datasets are used, with one representing current vegetation coverage in China and the other approximating its potential coverage without human intervention. The model results show potential impacts of LUC on climate variability and extremes. There are statistically significant changes of surface interannual climate variability simulated by the model. Using different vegetation datasets, significant changes in correlation coefficients between tropical Pacific Niño3.4 SST and precipitation and surface temperature over East Asia are identified, which indicate that changes in vegetation coverage may alter ENSO impacts on regional climate variability. Because of the lack of slowly varying surface processes when forests are removed and less rainfall is received following LUC, the ENSO signal simulated by the model becomes stronger. Results furthermore show that land-use could modulate characteristics of decadal variations in this region. When using current vegetation coverage, the model gives better simulation of observed climate variations in the region than the case using potential vegetation coverage. In addition, results suggest that land-use could be a potential factor contributing to the prolonged drought in central-west China. Changes in local climate extremes, including precipitation and surface temperature maxima and minima, are also identified. Overall, this study has illustrated the importance of further investigation of such important issues in future land-use studies.

  10. Ensemble climate projections of mean and extreme rainfall over Vietnam

    NASA Astrophysics Data System (ADS)

    Raghavan, S. V.; Vu, M. T.; Liong, S. Y.

    2017-01-01

    A systematic ensemble high resolution climate modelling study over Vietnam has been performed using the PRECIS model developed by the Hadley Center in UK. A 5 member subset of the 17-member Perturbed Physics Ensembles (PPE) of the Quantifying Uncertainty in Model Predictions (QUMP) project were simulated and analyzed. The PRECIS model simulations were conducted at a horizontal resolution of 25 km for the baseline period 1961-1990 and a future climate period 2061-2090 under scenario A1B. The results of model simulations show that the model was able to reproduce the mean state of climate over Vietnam when compared to observations. The annual cycles and seasonal averages of precipitation over different sub-regions of Vietnam show the ability of the model in also reproducing the observed peak and magnitude of monthly rainfall. The climate extremes of precipitation were also fairly well captured. Projections of future climate show both increases and decreases in the mean climate over different regions of Vietnam. The analyses of future extreme rainfall using the STARDEX precipitation indices show an increase in 90th percentile precipitation (P90p) over the northern provinces (15-25%) and central highland (5-10%) and over southern Vietnam (up to 5%). The total number of wet days (Prcp) indicates a decrease of about 5-10% all over Vietnam. Consequently, an increase in the wet day rainfall intensity (SDII), is likely inferring that the projected rainfall would be much more severe and intense which have the potential to cause flooding in some regions. Risks due to extreme drought also exist in other regions where the number of wet days decreases. In addition, the maximum 5 day consecutive rainfall (R5d) increases by 20-25% over northern Vietnam but decreases in a similar range over the central and southern Vietnam. These results have strong implications for the management water resources, agriculture, bio diversity and economy and serve as some useful findings to be

  11. 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

  12. Pattern Detection and Extreme Value Analysis on Large Climate Data

    NASA Astrophysics Data System (ADS)

    Prabhat, M.; Byna, S.; Paciorek, C.; Weber, G.; Wu, K.; Yopes, T.; Wehner, M. F.; Ostrouchov, G.; Pugmire, D.; Strelitz, R.; Collins, W.; Bethel, W.

    2011-12-01

    We consider several challenging problems in climate that require quantitative analysis of very large data volumes generated by modern climate simulations. We demonstrate new software capable of addressing these challenges that is designed to exploit petascale platforms using state-of-the-art methods in high performance computing. Atmospheric rivers and Hurricanes are important classes of extreme weather phenomena. Developing analysis tools that can automatically detect these events in large climate datasets can provide us with invaluable information about the frequency of these events. Application of these tools to different climate model outputs can provide us with quality metrics that evaluate whether models produce this important class of phenomena and how the statistics of these events will likely vary in the future. In this work, we present an automatic technique for detecting atmospheric rivers. We use techniques from image processing and topological analysis to extract these features. We implement this technique in a massively parallel fashion on modern supercomputing platforms, and apply the resulting software to both observational data and various models from the CMIP-3 archive. We have successfully completed atmospheric river detections on 1TB of data on 10000 hopper cores in 10 seconds. For hurricane tracking, we have adapted code from GFDL to run in parallel on large datasets. We present results from the application of this code to some recent high resolution CAM5 simulations. Our code is capable of processing 1TB of data in 10 seconds. Extreme value analysis involves statistical techniques for estimating the probability of extreme events and variations in the probabilities over time and space. Because of their rarity, there is a high degree of uncertainty when estimating the behavior of extremes from data at any one location. We are developing a local likelihood approach to borrow strength from multiple locations, with uncertainty estimated using the

  13. Modelling extreme climatic events in Guadalquivir Estuary ( Spain)

    NASA Astrophysics Data System (ADS)

    Delgado, Juan; Moreno-Navas, Juan; Pulido, Antoine; García-Lafuente, Juan; Calero Quesada, Maria C.; García, Rodrigo

    2017-04-01

    Extreme climatic events, such as heat waves and severe storms are predicted to increase in frequency and magnitude as a consequence of global warming but their socio-ecological effects are poorly understood, particularly in estuarine ecosystems. The Guadalquivir Estuary has been anthropologically modified several times, the original salt marshes have been transformed to grow rice and cotton and approximately one-fourth of the total surface of the estuary is now part of two protected areas, one of them is a UNESCO, MAB Biosphere Reserve. The climatic events are most likely to affect Europe in forthcoming decades and a further understanding how these climatic disturbances drive abrupt changes in the Guadalquivir estuary is needed. A barotropic model has been developed to study how severe storm events affects the estuary by conducting paired control and climate-events simulations. The changes in the local wind and atmospheric pressure conditions in the estuary have been studied in detail and several scenarios are obtained by running the model under control and real storm conditions. The model output has been validated with in situ water elevation and good agreement between modelled and real measurements have been obtained. Our preliminary results show that the model demonstrated the capability describe of the tide-surge levels in the estuary, opening the possibility to study the interaction between climatic events and the port operations and food production activities. The barotropic hydrodynamic model provide spatially explicit information on the key variables governing the tide dynamics of estuarine areas under severe climatic scenarios . The numerical model will be a powerful tool in future climate change mitigation and adaptation programs in a complex socio-ecological system.

  14. 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.

  15. Climate, not conflict, explains extreme Middle East dust storm

    NASA Astrophysics Data System (ADS)

    Parolari, Anthony J.; Li, Dan; Bou-Zeid, Elie; Katul, Gabriel G.; Assouline, Shmuel

    2016-11-01

    The recent dust storm in the Middle East (Sepember 2015) was publicized in the media as a sign of an impending ‘Dust Bowl.’ Its severity, demonstrated by extreme aerosol optical depth in the atmosphere in the 99th percentile compared to historical data, was attributed to the ongoing regional conflict. However, surface meteorological and remote sensing data, as well as regional climate model simulations, support an alternative hypothesis: the historically unprecedented aridity played a more prominent role, as evidenced by unusual climatic and meteorological conditions prior to and during the storm. Remotely sensed normalized difference vegetation index demonstrates that vegetation cover was high in 2015 relative to the prior drought and conflict periods, suggesting that agricultural activity was not diminished during that year, thus negating the media narrative. Instead, meteorological simulations using the Weather Research and Forecasting (WRF) model show that the storm was associated with a cyclone and ‘Shamal’ winds, typical for dust storm generation in this region, that were immediately followed by an unusual wind reversal at low levels that spread dust west to the Mediterranean Coast. These unusual meteorological conditions were aided by a significant reduction in the critical shear stress due to extreme dry and hot conditions, thereby enhancing dust availability for erosion during this storm. Concluding, unusual aridity, combined with unique synoptic weather patterns, enhanced dust emission and westward long-range transport across the region, thus generating the extreme storm.

  16. Early Benefits of Mitigation in Risk of Regional Climate Extremes

    NASA Astrophysics Data System (ADS)

    Ciavarella, Andrew; Stott, Peter; Lowe, Jason

    2015-04-01

    Large differences in climate outcomes are projected over the coming century depending on whether greenhouse gas emissions continue on a business as usual path or are substantially reduced following an aggressive mitigation strategy. However, it has previously been claimed that it will take many decades for there to be any significant difference between paths of aggressive mitigation and business as usual with the emergence of differences only seen towards the middle of the century. Here we show that important differences in our exposure to risk of climate extremes in many land regions emerges much more quickly. Without substantial mitigation, in many regions of the world, extreme (one in 20-year) seasonal, regional near surface air temperatures are found to have become more than twice as likely within only 15 years (i.e. by 2030). Therefore our exposure to climate risk is reduced substantially and rapidly with aggressive mitigation. This demonstrates that the benefits of mitigation are realised rapidly and it is not necessary to wait until the middle of the century as has previously been claimed.

  17. 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.

  18. Climate projection of extreme wind speed regime in the Arctic

    NASA Astrophysics Data System (ADS)

    Surkova, Galina; Sokolova, Larisa

    2016-04-01

    Extreme surface wind events over the Arctic (60-90N, 0-360 E) are studied for the modern climate and for its future possible changes on the base of ERA-Interim reanalysis data and CMIP5 scenario RCP8.5. Horizontal surface wind speed (10 m) probability distribution functions in every grid point of reanalysis and models data over the Arctic were evaluated as well as wind speed for 50, 95, 99, 99.9 percentiles (V0.50, V0.95, V0.99, V0.999). At first, changes of V0.50, V0.95, V0.99, V0.999 were studied on the base of ERA-Interim reanalysis for 1981-2010. Results showed regional inhomogenity of wind speed trend intensity. Also, analysis was made for zonal means and separate sectors of the Arctic. To study climate projection of high wind speed there were taken u,v values from CMIP5 numerical experiments for 1961-1990 (Historical) and 2081-2100 (RCP8.5). RCP8.5 scenario was chosen as having the most pronounced response in the climate system, which gave more statistical significance to the calculated trends. Modeled extreme wind speeds for the total Arctic and zonal means show rather good agreement with reanalysis data (compared for decades 1981-1990, 1991-2000). At the same time regional intermodel variability of wind speed is revealed. Trend of extreme surface wind speed in 21 century and for 2081-2100 over the Arctic are analyzed for each model. The study was supported by the Russian Science Foundation (project no. 14-37-00038).

  19. Impact of Climate Change on Extreme Rainfall in France Throughout Trend Detections in Average Climatic Characteristics

    NASA Astrophysics Data System (ADS)

    Cantet, P.; Arnaud, P.

    2008-12-01

    The great interest on climate change during these last years has led to a quasi unanimous conclusion for scientists: the Earth climate changes. An increase of precipitation in the middle and high latitude area of north hemisphere was detected. In order to prevent hydrological risks, it's interesting to know if these global changes lead to an increase of extreme events. Indeed in the hydrologic context, the estimation of return period is primary for hydraulic building dimensioning. When considering problem of fire, urbanisation, hydrological installations, the study of water runoff alone can be misleading. So we must do a preliminary work on rainfall. However climate models have difficulties to represent efficiently extreme events. Moreover classical statistical methods seem to be limited because of the lack of very long series which can lead to a bad estimation of distribution tails. An original approach is applied to estimate impacts of climate change on extreme events in using an hourly rainfall stochastic generator which can be coupled with a rainfall-runoff model. The climate evolution is detected by the generator parameters. These parameters are estimated by an average, and not by extreme values, of climatic characteristics. From daily information of 139 rain gauge stations, evolution of generator parameters has been studied in the metropolitan France between 1960 and 2003. We applied the Poisson-Pareto-Peak-Over-Threshold model and linear trend has been tested by the Maximum Likelihood Ratio test. Parameter evolution has been evaluated from a regional approach in clustering several stations. Changes on average rainfall characteristics are amplified on extremes. The observed trends occur mainly between December and May. Taking into account the climate change doesn't lead to a big change in the quantiles estimation compared to their estimation under a hypothesis of climate stationary. But if observed trends are confirmed in the future, extreme event occurrence

  20. Climate change and the frequency of simultaneous extreme heat events

    NASA Astrophysics Data System (ADS)

    Coffel, E.; Horton, R. M.; de Sherbinin, A. M.

    2016-12-01

    Recent heat waves have caused significant loss of life and economic damage across the world. As climate change progresses throughout the 21st century the frequency, intensity, and duration of these events is expected to increase, likely leading to enhanced societal impacts. Over many regions, there is emerging evidence that the most extreme heat events may be increasing in magnitude at a higher rate than mean temperature. This may be due to soil moisture interactions or changes in large-scale dynamics that could contribute to long-lived hot conditions, allowing for atmospheric heat build-up and even higher temperatures. While an increase in the frequency of simultaneous heat events in different parts of the world is expected due to statistics alone as temperatures rise, there has been relatively little research on concurrent heat extremes, and/or heat extremes of large spatial extent. This study investigates potential physical mechanisms that could enhance or minimize concurrent heat risk, relative to the changes in heat extremes expected due to mean warming alone. In addition, we analyze the statistics of widespread or concurrent heat events and some of their potential impacts in an increasingly economically interconnected world.

  1. When it rains, it pours: future climate extremes and health.

    PubMed

    Patz, Jonathan A; Grabow, Maggie L; Limaye, Vijay S

    2014-01-01

    The accelerating accumulation of greenhouse gases in the Earth's atmosphere is changing global environmental conditions in unprecedented and potentially irreversible ways. Climate change poses a host of challenges to the health of populations through complex direct and indirect mechanisms. The direct effects include an increased frequency of heat waves, rising sea levels that threaten low-lying communities, anticipated extremes in the global hydrologic cycle (droughts, floods, and intense storms), and adverse effects on agricultural production and fisheries due to environmental stressors and changes in land use. Indirectly, climate change is anticipated to threaten health by worsening urban air pollution and increasing rates of infectious (particularly waterborne and vector-borne) disease transmission. To provide a state-of-the-science review on the health consequences of a changing climate. Environmental public health researchers have concluded that, on balance, adverse health outcomes will dominate under these changed climatic conditions. The number of pathways through which climate change can affect the health of populations makes this environmental health threat one of the largest and most formidable of the new century. Geographic location plays an influential role the potential for adverse health effects caused by climate change, and certain regions and populations are more vulnerable than others to expected health effects. Two kinds of strategies are available for responding to climate change: mitigation policies (which aim to reduce greenhouse gas emissions) and adaptation measures (relating to preparedness for anticipated impacts). To better understand and address the complex nature of health risks posed by climate change, interdisciplinary collaboration is critical. Efforts to move beyond our current reliance on fossil fuels to cleaner, more sustainable energy sources may offer some of the greatest health opportunities in more than a century and cobenefits

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

    Treesearch

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

    2016-01-01

    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...

  3. 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.

  4. Tambora and the mackerel year: Phenology and fisheries during an extreme climate event.

    PubMed

    Alexander, Karen E; Leavenworth, William B; Willis, Theodore V; Hall, Carolyn; Mattocks, Steven; Bittner, Steven M; Klein, Emily; Staudinger, Michelle; Bryan, Alexander; Rosset, Julianne; Carr, Benjamin H; Jordaan, Adrian

    2017-01-01

    Global warming has increased the frequency of extreme climate events, yet responses of biological and human communities are poorly understood, particularly for aquatic ecosystems and fisheries. Retrospective analysis of known outcomes may provide insights into the nature of adaptations and trajectory of subsequent conditions. We consider the 1815 eruption of the Indonesian volcano Tambora and its impact on Gulf of Maine (GoM) coastal and riparian fisheries in 1816. Applying complex adaptive systems theory with historical methods, we analyzed fish export data and contemporary climate records to disclose human and piscine responses to Tambora's extreme weather at different spatial and temporal scales while also considering sociopolitical influences. Results identified a tipping point in GoM fisheries induced by concatenating social and biological responses to extreme weather. Abnormal daily temperatures selectively affected targeted fish species-alewives, shad, herring, and mackerel-according to their migration and spawning phenologies and temperature tolerances. First to arrive, alewives suffered the worst. Crop failure and incipient famine intensified fishing pressure, especially in heavily settled regions where dams already compromised watersheds. Insufficient alewife runs led fishers to target mackerel, the next species appearing in abundance along the coast; thus, 1816 became the "mackerel year." Critically, the shift from riparian to marine fisheries persisted and expanded after temperatures moderated and alewives recovered. We conclude that contingent human adaptations to extraordinary weather permanently altered this complex system. Understanding how adaptive responses to extreme events can trigger unintended consequences may advance long-term planning for resilience in an uncertain future.

  5. 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. © 2015 APJPH.

  6. Scaling and Intensification of Extreme Precipitation in High-Resolution Climate Change Simulations

    NASA Astrophysics Data System (ADS)

    Ban, Nikolina; Leutwyler, David; Lüthi, Daniel; Schär, Christoph

    2017-04-01

    Climate change projections of extreme precipitation are of great interest due to hydrological impacts such as droughts, floods, erosion, landslides and debris flows. Despite the trend towards dryer conditions over Europe, many climate simulations project increases of heavy precipitation events, while some theoretical studies have raised the possibility of dramatic increases in hourly events (by up to 14% per degree warming). However, conventional climate models are not suited to assess short-term heavy events due to the need to parameterize deep convection. High-resolution climate models with kilometer-scale grid spacing at which parameterization of convection can be switched off, significantly improve the simulation of heavy precipitation and can alter the climate change signal (e.g., Ban et al., 2015). Here we present decade-long high-resolution climate change simulations at horizontal resolution of 2.2 km over Europe on a computational domain with 1536x1536x60 grid points. These simulations have become feasible with a new version of the COSMO model that runs entirely on Graphics Processing Units. We compare a present-day climate simulation, driven by ERA-Interim reanalysis (Leutwyler at al., 2016), with a Pseudo-Global Warming (PGW) simulation The PGW simulation is driven by the slowly evolving mean seasonal cycle of the climate changes (derived from the CMIP5 model), superimposed on the ERA-Interim reanalysis. With this approach, the resulting changes are due to large scale warming of the atmosphere and due to slow-varying circulation changes. We will present the differences in climate change signal between conventional and high-resolution climate models, and discuss the thermodynamic effects on intensification of extreme precipitation. Ban N., J. Schmidli and C. Schär, 2015: Heavy precipitation in a changing climate: Does short-term summer precipitation increase faster? Geophys. Res. Lett., 42 (4), 1165-1172 Leutwyler, D., D. Lüthi, N. Ban, O. Fuhrer and C

  7. Urbanization, Extreme Climate Hazards and Food, Energy Water Security

    NASA Astrophysics Data System (ADS)

    Romero-Lankao, P.; Davidson, D.; McPhearson, T.

    2016-12-01

    Research is urgently needed that incorporates the interconnected nature of three critical resources supporting our cities: food, energy and water. Cities are increasing demands for food, water and energy resources that in turn stress resource supplies, creating risks of negative impacts to human and ecological wellbeing. Simultaneously, shifts in climatic conditions, including extremes such as floods, heat, and droughts, threaten the sustainable availability of adequate quantities and qualities of food, energy and water (FEW) resources needed for resilient cities and ecosystems. These resource flows cannot be treated in isolation simply because they are interconnected: shifts in food, energy or water dynamics in turn affect the others, affecting the security of the whole - i.e., FEW nexus security. We present a framework to examine the dynamic interactions of urbanization, FEW nexus security and extreme hazard risks, with two overarching research questions: Do existing and emerging actions intended to enhance a population's food, water and energy security have the capacity to ensure FEW nexus security in the face of changing climate and urban development conditions? Can we identify a common set of social, ecological and technological conditions across a diversity of urban-regions that support the emergence of innovations that can lead to structural transformations for FEW nexus security?

  8. 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

  9. 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.

  10. Climate change, extreme weather events, and us health impacts: what can we say?

    PubMed

    Mills, David M

    2009-01-01

    Address how climate change impacts on a group of extreme weather events could affect US public health. A literature review summarizes arguments for, and evidence of, a climate change signal in select extreme weather event categories, projections for future events, and potential trends in adaptive capacity and vulnerability in the United States. Western US wildfires already exhibit a climate change signal. The variability within hurricane and extreme precipitation/flood data complicates identifying a similar climate change signal. Health impacts of extreme events are not equally distributed and are very sensitive to a subset of exceptional extreme events. Cumulative uncertainty in forecasting climate change driven characteristics of extreme events and adaptation prevents confidently projecting the future health impacts from hurricanes, wildfires, and extreme precipitation/floods in the United States attributable to climate change.

  11. Autochthonous Chikungunya Transmission and Extreme Climate Events in Southern France

    PubMed Central

    Roiz, David; Boussès, Philippe; Simard, Frédéric; Paupy, Christophe; Fontenille, Didier

    2015-01-01

    Background Extreme precipitation events are increasing as a result of ongoing global warming, but controversy surrounds the relationship between flooding and mosquito-borne diseases. A common view among the scientific community and public health officers is that heavy rainfalls have a flushing effect on breeding sites, which negatively affects vector populations, thereby diminishing disease transmission. During 2014 in Montpellier, France, there were at least 11 autochthonous cases of chikungunya caused by the invasive tiger mosquito Aedes albopictus in the vicinity of an imported case. We show that an extreme rainfall event increased and extended the abundance of the disease vector Ae. albopictus, hence the period of autochthonous transmission of chikungunya. Methodology/Principal Findings We report results from close monitoring of the adult and egg population of the chikungunya vector Ae. albopictus through weekly sampling over the entire mosquito breeding season, which revealed an unexpected pattern. Statistical analysis of the seasonal dynamics of female abundance in relation to climatic factors showed that these relationships changed after the heavy rainfall event. Before the inundations, accumulated temperatures are the most important variable predicting Ae. albopictus seasonal dynamics. However, after the inundations, accumulated rainfall over the 4 weeks prior to capture predicts the seasonal dynamics of this species and extension of the transmission period. Conclusions/Significance Our empirical data suggests that heavy rainfall events did increase the risk of arbovirus transmission in Southern France in 2014 by favouring a rapid rise in abundance of vector mosquitoes. Further studies should now confirm these results in different ecological contexts, so that the impact of global change and extreme climatic events on mosquito population dynamics and the risk of disease transmission can be adequately understood. PMID:26079620

  12. Extreme climate events counteract the effects of climate and land-use changes in Alpine treelines.

    PubMed

    Barros, Ceres; Guéguen, Maya; Douzet, Rolland; Carboni, Marta; Boulangeat, Isabelle; Zimmermann, Niklaus E; Münkemüller, Tamara; Thuiller, Wilfried

    2017-02-01

    1. Climate change and extreme events, such as drought, threaten ecosystems worldwide and in particular mountain ecosystems, where species often live at their environmental tolerance limits. In the European Alps, plant communities are also influenced by land-use abandonment leading to woody encroachment of subalpine and alpine grasslands. 2. In this study, we explored how the forest-grassland ecotone of Alpine treelines will respond to gradual climate warming, drought events and land-use change in terms of forest expansion rates, taxonomic diversity and functional composition. We used a previously validated dynamic vegetation model, FATE-HD, parameterised for plant communities in the Ecrins National Park in the French Alps. 3. Our results showed that intense drought counteracted the forest expansion at higher elevations driven by land-use abandonment and climate change, especially when combined with high drought frequency (occurring every 2 or less than 2 years). 4. Furthermore, intense and frequent drought accelerated the rates of taxonomic change and resulted in overall higher taxonomic spatial heterogeneity of the ecotone than would be expected under gradual climate and land-use changes only. 5. Synthesis and applications. The results from our model show that intense and frequent drought counteracts forest expansion driven by climate and land-use changes in the forest-grassland ecotone of Alpine treelines. We argue that land-use planning must consider the effects of extreme events, such as drought, as well as climate and land-use changes, since extreme events might interfere with trends predicted under gradual climate warming and agricultural abandonment.

  13. Urban precipitation extremes: How reliable are regional climate models?

    NASA Astrophysics Data System (ADS)

    Mishra, Vimal; Dominguez, Francina; Lettenmaier, Dennis P.

    2012-02-01

    We evaluate the ability of regional climate models (RCMs) that participated in the North American Regional Climate Change Assessment Program (NARCCAP) to reproduce the historical season of occurrence, mean, and variability of 3 and 24-hour precipitation extremes for 100 urban areas across the United States. We show that RCMs with both reanalysis and global climate model (GCM) boundary conditions behave similarly and underestimate 3-hour precipitation maxima across almost the entire U.S. RCMs with both boundary conditions broadly capture the season of occurrence of precipitation maxima except in the interior of the western U.S. and the southeastern U.S. On the other hand, the RCMs do much better in identifying the season of 24-hour precipitation maxima. For mean annual precipitation maxima, regardless of the boundary condition, RCMs consistently show high (low) bias for locations in the western (eastern) U.S. Our results indicate that RCM-simulated 3-hour precipitation maxima at 100-year return period could be considered acceptable for stormwater infrastructure design at less than 12% of the 100 urban areas (regardless of boundary conditions). RCM performance for 24-hour precipitation maxima was slightly better, with performance acceptable for stormwater infrastructure design judged adequate at about 25% of the urban areas.

  14. 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

  15. 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.

  16. 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.

  17. 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

  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. Assessment of climate variability and hydrological alterations in Kaidu Basin

    NASA Astrophysics Data System (ADS)

    Shen, Yan-Jun; Shen, Yanjun; Fink, Manfred; Kralisch, Sven; Brenning, Alexander

    2017-04-01

    Climate change and hydrological alterations are major concerns in a mountain river ecosystem. We provide an essential assessment of climate variability (1961-2011) in Kaidu basin by means of Mann-Kendall test and cumulative anomalies. The Indicator of Hydrologic Alteration (IHA) was further performed to analyze hydrological alterations (1972-2008). Change in the triggering of snowmelt runoff timing was analyzed by the winter/spring snowmelt runoff center time (WSCT). Results reveal that annual precipitation and temperature show an increase tendency, but with a significant trend in winter and summer, respectively, while the discharge reveals significant rises in both annual and seasonal scales. However, all the hydro-meteorological parameters show an obvious increase tendency especially in the mid-1990s. WSCT has a significant decreasing trend and was observed earlier by nearly 10 days in Kaidu Basin. Higher relationship between WSCT with temperatures (March to April, R= - 0.51) and precipitation (February to March, R=0.33) were found that temperature may play a major role in causing the earlier WSCT. Account for the reservoirs influences, the rise rate and monthly flows have increased evidently before and after the reservoirs regulation. Monthly streamflow was found higher in pre-impact (1972-1992) than post-impact period (1993-2008) based on the flow duration curves. Nevertheless, the base flow index displayed no change before and after the impact period. Consequently, both of climate change and reservoir regulation lead to a concentrated streamflow. Research should take this influence into consideration in hydrological analysis and modelling in terms of uncertainties. These findings deepen our understanding of climate change and hydrological alterations in Kaidu basin, and are useful for flood risk regulation, ecological restoration and future hydropower plants. Keywords: Climate change; Spring snowmelt runoff time; WSCT; hydrological alterations; IHA

  20. Climate extremes promote fatal co-infections during canine distemper epidemics in African lions.

    PubMed

    Munson, Linda; Terio, Karen A; Kock, Richard; Mlengeya, Titus; Roelke, Melody E; Dubovi, Edward; Summers, Brian; Sinclair, Anthony R E; Packer, Craig

    2008-06-25

    Extreme climatic conditions may alter historic host-pathogen relationships and synchronize the temporal and spatial convergence of multiple infectious agents, triggering epidemics with far greater mortality than those due to single pathogens. Here we present the first data to clearly illustrate how climate extremes can promote a complex interplay between epidemic and endemic pathogens that are normally tolerated in isolation, but with co-infection, result in catastrophic mortality. A 1994 canine distemper virus (CDV) epidemic in Serengeti lions (Panthera leo) coincided with the death of a third of the population, and a second high-mortality CDV epidemic struck the nearby Ngorongoro Crater lion population in 2001. The extent of adult mortalities was unusual for CDV and prompted an investigation into contributing factors. Serological analyses indicated that at least five "silent" CDV epidemics swept through the same two lion populations between 1976 and 2006 without clinical signs or measurable mortality, indicating that CDV was not necessarily fatal. Clinical and pathology findings suggested that hemoparsitism was a major contributing factor during fatal epidemics. Using quantitative real-time PCR, we measured the magnitude of hemoparasite infections in these populations over 22 years and demonstrated significantly higher levels of Babesia during the 1994 and 2001 epidemics. Babesia levels correlated with mortalities and extent of CDV exposure within prides. The common event preceding the two high mortality CDV outbreaks was extreme drought conditions with wide-spread herbivore die-offs, most notably of Cape buffalo (Syncerus caffer). As a consequence of high tick numbers after the resumption of rains and heavy tick infestations of starving buffalo, the lions were infected by unusually high numbers of Babesia, infections that were magnified by the immunosuppressive effects of coincident CDV, leading to unprecedented mortality. Such mass mortality events may become

  1. Tackling extremes: challenges for ecological and evolutionary research on extreme climatic events.

    PubMed

    Bailey, Liam D; van de Pol, Martijn

    2016-01-01

    Extreme climatic events (ECEs) are predicted to become more frequent as the climate changes. A rapidly increasing number of studies - though few on animals - suggest that the biological consequences of ECEs can be severe. However, ecological research on the impacts of ECEs has been limited by a lack of cohesiveness and structure. ECEs are often poorly defined and have often been confusingly equated with climatic variability, making comparison between studies difficult. In addition, a focus on short-term studies has provided us with little information on the long-term implications of ECEs, and the descriptive and anecdotal nature of many studies has meant it is still unclear what the key research questions are. Synthesizing the current state of work is essential to identify ways to make progress. We conduct a synthesis of the literature and discuss conceptual and practical challenges faced by research on ECEs. We consider three steps to advance research. First, we discuss the importance of choosing an ECE definition and identify the pros and cons of 'climatological' and 'biological' definitions of ECEs. Secondly, we advocate research beyond short-term descriptive studies to address questions concerning the long-term implications of ECEs, focussing on selective pressures and phenotypically plastic responses and how they might differ from responses to a changing climatic mean. Finally, we encourage a greater focus on multi-event studies that help us understand the implications of changing patterns of ECEs, through the combined use of modelling, experimental and observational field studies. This study aims to open a discussion on the definitions, questions and methods currently used to study ECEs, which will lead to a more cohesive approach to future ECE research. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

  2. 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.

  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. 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 ...

  5. Investigating drought using extreme climatic indices over Idaho, USA

    NASA Astrophysics Data System (ADS)

    Sohrabi, M.; Ryu, J.

    2011-12-01

    trends in 46 stations, and 16 and 3 stations show negative and positive significant trends, relatively. Minimum SPI 1, 3, 6 and 12 month time scales indicate 36, 40, 43 and 42 negative trends and 6, 10, 14 and 16 stations out of them have significant trends, respectively. Results of extreme climatic and seasonal indices are completely consistent with that of PDSI and SPI. As such, findings highlight that water shortage in the southern part of Idaho, especially in Snake River basin, likely occurs in the near future possibly due to climate change.

  6. 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

  7. 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.

  8. How much do precipitation extremes change in a warming climate?

    NASA Astrophysics Data System (ADS)

    Shiu, Chein-Jung; Liu, Shaw Chen; Fu, Congbin; Dai, Aiguo; Sun, Ying

    2012-09-01

    Daily data from reanalyses of the European Centre for Medium-Range Weather Forecasts (ECMWF) and the National Centers for Environmental Prediction (NCEP) are analyzed to study changes in precipitation intensity with respect to global mean temperature. The results are in good agreement with those derived from the Global Precipitation Climatology Project (GPCP) data by Liu et al. (2009), providing an independent verification for large changes in the precipitation extremes: about 100% increase for the annual top 10% heavy precipitation and about 20% decrease for the light and moderate precipitation for one degree warming in the global temperature. These changes can substantially increase the risk of floods as well as droughts, thus severely affecting the global ecosystems. Atmospheric models used in the reanalysis mode, with the benefit of observed wind and moisture fields, appear to be capable of realistically simulating the change of precipitation intensity with global temperature. In comparison, coupled climate models are capable of simulating the shape of the change in precipitation intensity, but underestimate the magnitude of the change by about one order of magnitude. The most likely reason of the underestimation is that the typical spatial resolution of climate models is too coarse to resolve atmospheric convection.

  9. 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

  10. 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

  11. 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.

  12. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. 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.

  14. 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.

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

    NASA Astrophysics Data System (ADS)

    Yoon, Jin-Ho

    2017-04-01

    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. 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.

  17. Potential Impacts of Climate Change on Hydrological Extremes Across Europe

    NASA Astrophysics Data System (ADS)

    Donnelly, C.; Dahné, J.; Andersson, J.; Arheimer, B.

    2012-04-01

    Regional scale predictions of floods and droughts are particularly useful for demonstrating to the general public the potential impacts of climate change, for example for the European continent. The E-HYPE pan-European application of the HYPE model was used to simulate hydrological data at a median subbasin resolution of 215 km2 for all of Europe. This data was then used to calculate, at this resolution, a number of drought and flood indices for today's climate and for a small ensemble of bias-corrected regional climate change projections. Indices calculated include the 1 in 10 and 1 in 50 year flood levels, mean annual high water discharge, mean annual low water discharge, number of days per year with hydrological drought and agricultural drought and the intensity of days with agricultural drought. Maps showing the relative changes in these variables for various time periods in the future were then made from the results. These maps may then be used to indicate 'hot-spots' for where hydrological extremes are important today and for where large changes in flood and drought levels or frequency may be expected for a future climate. The E-HYPE model, used to make these predictions, has been evaluated using a large data set of discharge observations (over 800) at independent sites across Europe. The model uses readily available pan-European input data sets and a single parameter set across the entire continent. This homogenous treatment of the model domain means that results from all over Europe are easily comparable. Validation is made to ensure the model simulates discharge volumes and daily variation at each station, but novel for this study is that a validation of the model's ability to capture the drought and flood indices was also made. Although E-HYPE is a large domain model, the high subbasin resolution means that these results are available at high-resolution across Europe. Nevertheless, prediction uncertainty increases with decreasing catchment scale, so this

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. (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

  3. 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.

  4. Climate change alters growing season flux dynamics in mesic grasslands

    NASA Astrophysics Data System (ADS)

    Petrie, Matt D.; Brunsell, Nathaniel A.; Nippert, Jesse B.

    2012-02-01

    Changing climate could affect the functioning of grassland ecosystems through variation in climate forcings and by altering the interactions of forcings with ecological processes. Both the short and long-term effects of changing forcings and ecosystem interactions are a critical part of future impacts to ecosystem ecology and hydrology. To explore these interactions and identify possible characteristics of climate change impacts to mesic grasslands, we employ a low-dimensional modeling framework to assess the IPCC A1B scenario projections for the Central Plains of the United States; forcings include increased precipitation variability, increased potential evaporation, and earlier growing season onset. These forcings are also evaluated by simulations of vegetation photosynthetic capacity to explore the seasonal characteristics of the vegetation carbon assimilation response for species at the Konza Prairie in North Central Kansas, USA. The climate change simulations show decreases in mean annual soil moisture and and carbon assimilation and increased variation in water and carbon fluxes during the growing season. Simulations of the vegetation response show increased variation at the species-level instead of at a larger class scale, with important heterogeneity in how individual species respond to climate forcings. Understanding the drivers and relationships behind these ecosystem responses is important for understanding the likely scale of climate change impacts and for exploring the mechanisms shaping growing season dynamics in grassland ecosystems.

  5. 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.

  6. 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.

  7. Anthropogenic climate change has altered primary productivity in Lake Superior.

    PubMed

    O'Beirne, M D; Werne, J P; Hecky, R E; Johnson, T C; Katsev, S; Reavie, E D

    2017-06-09

    Anthropogenic climate change has the potential to alter many facets of Earth's freshwater resources, especially lacustrine ecosystems. The effects of anthropogenic changes in Lake Superior, which is Earth's largest freshwater lake by area, are not well documented (spatially or temporally) and predicted future states in response to climate change vary. Here we show that Lake Superior experienced a slow, steady increase in production throughout the Holocene using (paleo)productivity proxies in lacustrine sediments to reconstruct past changes in primary production. Furthermore, data from the last century indicate a rapid increase in primary production, which we attribute to increasing surface water temperatures and longer seasonal stratification related to longer ice-free periods in Lake Superior due to anthropogenic climate warming. These observations demonstrate that anthropogenic effects have become a prominent influence on one of Earth's largest, most pristine lacustrine ecosystems.

  8. Anthropogenic climate change has altered primary productivity in Lake Superior

    NASA Astrophysics Data System (ADS)

    O'Beirne, M. D.; Werne, J. P.; Hecky, R. E.; Johnson, T. C.; Katsev, S.; Reavie, E. D.

    2017-06-01

    Anthropogenic climate change has the potential to alter many facets of Earth's freshwater resources, especially lacustrine ecosystems. The effects of anthropogenic changes in Lake Superior, which is Earth's largest freshwater lake by area, are not well documented (spatially or temporally) and predicted future states in response to climate change vary. Here we show that Lake Superior experienced a slow, steady increase in production throughout the Holocene using (paleo)productivity proxies in lacustrine sediments to reconstruct past changes in primary production. Furthermore, data from the last century indicate a rapid increase in primary production, which we attribute to increasing surface water temperatures and longer seasonal stratification related to longer ice-free periods in Lake Superior due to anthropogenic climate warming. These observations demonstrate that anthropogenic effects have become a prominent influence on one of Earth's largest, most pristine lacustrine ecosystems.

  9. Tambora and the mackerel year: Phenology and fisheries during an extreme climate event

    PubMed Central

    Alexander, Karen E.; Leavenworth, William B.; Willis, Theodore V.; Hall, Carolyn; Mattocks, Steven; Bittner, Steven M.; Klein, Emily; Staudinger, Michelle; Bryan, Alexander; Rosset, Julianne; Carr, Benjamin H.; Jordaan, Adrian

    2017-01-01

    Global warming has increased the frequency of extreme climate events, yet responses of biological and human communities are poorly understood, particularly for aquatic ecosystems and fisheries. Retrospective analysis of known outcomes may provide insights into the nature of adaptations and trajectory of subsequent conditions. We consider the 1815 eruption of the Indonesian volcano Tambora and its impact on Gulf of Maine (GoM) coastal and riparian fisheries in 1816. Applying complex adaptive systems theory with historical methods, we analyzed fish export data and contemporary climate records to disclose human and piscine responses to Tambora’s extreme weather at different spatial and temporal scales while also considering sociopolitical influences. Results identified a tipping point in GoM fisheries induced by concatenating social and biological responses to extreme weather. Abnormal daily temperatures selectively affected targeted fish species—alewives, shad, herring, and mackerel—according to their migration and spawning phenologies and temperature tolerances. First to arrive, alewives suffered the worst. Crop failure and incipient famine intensified fishing pressure, especially in heavily settled regions where dams already compromised watersheds. Insufficient alewife runs led fishers to target mackerel, the next species appearing in abundance along the coast; thus, 1816 became the “mackerel year.” Critically, the shift from riparian to marine fisheries persisted and expanded after temperatures moderated and alewives recovered. We conclude that contingent human adaptations to extraordinary weather permanently altered this complex system. Understanding how adaptive responses to extreme events can trigger unintended consequences may advance long-term planning for resilience in an uncertain future. PMID:28116356

  10. Climate Impacts on Extreme Energy Consumption of Different Types of Buildings

    PubMed Central

    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

  11. 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.

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

    PubMed

    Sanz-Lázaro, Carlos

    2016-08-16

    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.

  13. 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

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

    NASA Astrophysics Data System (ADS)

    Sanz-Lázaro, Carlos

    2016-08-01

    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.

  15. Quantifying thermal extremes and biological variation to predict evolutionary responses to changing climate.

    PubMed

    Kingsolver, Joel G; Buckley, Lauren B

    2017-06-19

    Central ideas from thermal biology, including thermal performance curves and tolerances, have been widely used to evaluate how changes in environmental means and variances generate changes in fitness, selection and microevolution in response to climate change. We summarize the opportunities and challenges for extending this approach to understanding the consequences of extreme climatic events. Using statistical tools from extreme value theory, we show how distributions of thermal extremes vary with latitude, time scale and climate change. Second, we review how performance curves and tolerances have been used to predict the fitness and evolutionary responses to climate change and climate gradients. Performance curves and tolerances change with prior thermal history and with time scale, complicating their use for predicting responses to thermal extremes. Third, we describe several recent case studies showing how infrequent extreme events can have outsized effects on the evolution of performance curves and heat tolerance. A key issue is whether thermal extremes affect reproduction or survival, and how these combine to determine overall fitness. We argue that a greater focus on tails-in the distribution of environmental extremes, and in the upper ends of performance curves-is needed to understand the consequences of extreme events.This article is part of the themed issue 'Behavioural, ecological and evolutionary responses to extreme climatic events'. © 2017 The Author(s).

  16. 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

  17. 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.

  18. 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

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

    USGS Publications Warehouse

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

    2016-01-01

    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.

  20. 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.

  1. Environmental parameters altered by climate change affect the activity of soil microorganisms involved in bioremediation.

    PubMed

    Alkorta, Itziar; Epelde, Lur; Garbisu, Carlos

    2017-09-15

    Bioremediation, based on the use of microorganisms to break down pollutants, can be very effective at reducing soil pollution. But the climate change we are now experiencing is bound to have an impact on bioremediation performance, since the activity and degrading abilities of soil microorganisms are dependent on a series of environmental parameters which are themselves being altered by climate change, such as soil temperature, moisture, amount of root exudates, etc. Many climate-induced effects on soil microorganisms occur indirectly through changes in plant growth and physiology derived from increased atmospheric CO2 concentrations and temperatures, the alteration of precipitation patterns, etc., with a concomitant effect on rhizoremediation performance (i.e. the plant-assisted microbial degradation of pollutants in the rhizosphere). But these effects are extremely complex and mediated by processes such as acclimation and adaptation. Besides, soil microorganisms form complex networks of interactions with a myriad of organisms from many taxonomic groups which will also be affected by climate change, further complicating data interpretation. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Knowledge discovery and nonlinear modeling can complement climate model simulations for predictive insights about climate extremes and their impacts

    NASA Astrophysics Data System (ADS)

    Ganguly, A. R.; Steinbach, M.; Kumar, V.

    2009-12-01

    The IPCC AR4 not only provided conclusive evidence about anticipated global warming at century scales, but also indicated with a high level of certainty that the warming is caused by anthropogenic emissions. However, an outstanding knowledge-gap is to develop credible projections of climate extremes and their impacts. Climate extremes are defined in this context as extreme weather and hydrological events, as well as changes in regional hydro-meteorological patterns, especially at decadal scales. While temperature extremes from climate models have relatively better skills, hydrological variables and their extremes have significant shortcomings. Credible projections about tropical storms, sea level rise, coastal storm surge, land glacier melts, and landslides remain elusive. The next generation of climate models is expected to have higher precision. However, their ability to provide more accurate projections of climate extremes remains to be tested. Projections of observed trends into the future may not be reliable in non-stationary environments like climate change, even though functional relationships derived from physics may hold. On the other hand, assessments of climate change impacts which are useful for stakeholders and policy makers depend critically on regional and decadal scale projections of climate extremes. Thus, climate impacts scientists often need to develop qualitative inferences about the not so-well predicted climate extremes based on insights from observations (e.g., increased hurricane intensity) or conceptual understanding (e.g., relation of wildfires to regional warming or drying and hurricanes to SST). However, neither conceptual understanding nor observed trends may be reliable when extrapolating in a non-stationary environment. These urgent societal priorities offer fertile grounds for nonlinear modeling and knowledge discovery approaches. Thus, qualitative inferences on climate extremes and impacts may be transformed into quantitative

  3. 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.

  4. 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

  5. Extreme Weather Events and Interconnected Infrastructures: Toward More Comprehensive Climate Change Planning [Meeting challenges in understanding impacts of extreme weather events on connected infrastructures

    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.

  6. Extreme Weather Events and Interconnected Infrastructures: Toward More Comprehensive Climate Change Planning [Meeting challenges in understanding impacts of extreme weather events on connected infrastructures

    SciTech Connect

    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.

  7. Abrupt shifts in phenology and vegetation productivity under climate extremes

    USDA-ARS?s Scientific Manuscript database

    Amplification of the hydrologic cycle as a consequence of global warming is predicted to increase climate variability and the frequency and severity of droughts. Predicting how ecosystems will be affected by climate change requires not only reliable forecasts of future climate, but also observationa...

  8. 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.

  9. Evaluation of reanalysis climate simulations for the prediction of extreme runoff characteristics

    NASA Astrophysics Data System (ADS)

    Coskun, Mehmet; Samaniego, Luis; Kumar, Rohini

    2010-05-01

    Discharge regimes of river basins are expected to be altered due to possible effects of global warming. For planning and water resources management, it is fundamental to estimate the probability of occurrence of extreme hydrological events such as magnitude and frequency of floods and droughts. So far, it is a matter of debate whether actual Global and Regional Climate Model outputs or their reanalysis products (bias corrected) are able to provide a reasonable estimate of the meteorological variables that are required to force a distributed hydrologic model. In this study, we will evaluate various climate simulations for their reliability to predict extreme runoff characteristics in three German mesoscale river basins with various sizes and hydro-meteorological conditions: Neckar (12 700 km2), Bode (3 300 km2), and Mulde (2 700 km2). Reanalysis of the global atmosphere and surface conditions were obtained from the European Centre for Medium-Range Weather Forecast (ECMWF) Reanalysis (ERA-40) for the period from 1957 to 2002. These data will be used to force a grid based mesoscale hydrologic model calibrated with past meteorological and discharge observations. Several runoff characteristics will be estimated based on daily discharge simulations and then compared with their corresponding estimates derived from daily streamflow observations. Finally, nonparametric statistical test (e.g. Kolmogorov-Smirnov test) and Tukey's depth function will be employed to test two null hypotheses: 1) Meteorological observations and the reanalysis data are realisations from a common generating process, and 2) The probability of occurrence of extreme runoff characteristics obtained from both data sets is similar.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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

  15. Nonstationary Extreme Value Analysis in a Changing Climate: A Software Package

    NASA Astrophysics Data System (ADS)

    Cheng, L.; AghaKouchak, A.; Gilleland, E.

    2013-12-01

    Numerous studies show that climatic extremes have increased substantially in the second half of the 20th century. For this reason, analysis of extremes under a nonstationary assumption has received a great deal of attention. This paper presents a software package developed for estimation of return levels, return periods, and risks of climatic extremes in a changing climate. This MATLAB software package offers tools for analysis of climate extremes under both stationary and non-stationary assumptions. The Nonstationary Extreme Value Analysis (hereafter, NEVA) provides an efficient and generalized framework for analyzing extremes using Bayesian inference. NEVA estimates the extreme value parameters using a Differential Evolution Markov Chain (DE-MC) which utilizes the genetic algorithm Differential Evolution (DE) for global optimization over the real parameter space with the Markov Chain Monte Carlo (MCMC) approach and has the advantage of simplicity, speed of calculation and convergence over conventional MCMC. NEVA also offers the confidence interval and uncertainty bounds of estimated return levels based on the sampled parameters. NEVA integrates extreme value design concepts, data analysis tools, optimization and visualization, explicitly designed to facilitate analysis extremes in geosciences. The generalized input and output files of this software package make it attractive for users from across different fields. Both stationary and nonstationary components of the package are validated for a number of case studies using empirical return levels. The results show that NEVA reliably describes extremes and their return levels.

  16. Climate extremes are associated with invertebrate taxonomic and functional composition in mountain lakes.

    PubMed

    Boersma, Kate S; Nickerson, Avery; Francis, Clinton D; Siepielski, Adam M

    2016-11-01

    Climate change is expected to increase climate variability and the occurrence of extreme climatic events, with potentially devastating effects on aquatic ecosystems. However, little is known about the role of climate extremes in structuring aquatic communities or the interplay between climate and local abiotic and biotic factors. Here, we examine the relative influence of climate and local abiotic and biotic conditions on biodiversity and community structure in lake invertebrates. We sampled aquatic invertebrates and measured environmental variables in 19 lakes throughout California, USA, to test hypotheses of the relationship between climate, local biotic and environmental conditions, and the taxonomic and functional structure of aquatic invertebrate communities. We found that, while local biotic and abiotic factors such as habitat availability and conductivity were the most consistent predictors of alpha diversity, extreme climate conditions such as maximum summer temperature and dry-season precipitation were most often associated with multivariate taxonomic and functional composition. Specifically, sites with high maximum temperatures and low dry-season precipitation housed communities containing high abundances of large predatory taxa. Furthermore, both climate dissimilarity and abiotic dissimilarity determined taxonomic turnover among sites (beta diversity). These findings suggest that while local-scale environmental variables may predict alpha diversity, climatic variability is important to consider when projecting broad-scale aquatic community responses to the extreme temperature and precipitation events that are expected for much of the world during the next century.

  17. Multi-objective Optimization for the Robust Performance of Drinking Water Treatment Plants under Climate Change and Climate Extremes

    NASA Astrophysics Data System (ADS)

    Raseman, W. J.; Kasprzyk, J. R.; Rosario-Ortiz, F.; Summers, R. S.; Stewart, J.; Livneh, B.

    2016-12-01

    To promote public health, the United States Environmental Protection Agency (US EPA), and similar entities around the world enact strict laws to regulate drinking water quality. These laws, such as the Stage 1 and 2 Disinfectants and Disinfection Byproducts (D/DBP) Rules, come at a cost to water treatment plants (WTPs) which must alter their operations and designs to meet more stringent standards and the regulation of new contaminants of concern. Moreover, external factors such as changing influent water quality due to climate extremes and climate change, may force WTPs to adapt their treatment methods. To grapple with these issues, decision support systems (DSSs) have been developed to aid WTP operation and planning. However, there is a critical need to better address long-term decision making for WTPs. In this poster, we propose a DSS framework for WTPs for long-term planning, which improves upon the current treatment of deep uncertainties within the overall potable water system including the impact of climate on influent water quality and uncertainties in treatment process efficiencies. We present preliminary results exploring how a multi-objective evolutionary algorithm (MOEA) search can be coupled with models of WTP processes to identify high-performing plans for their design and operation. This coupled simulation-optimization technique uses Borg MOEA, an auto-adaptive algorithm, and the Water Treatment Plant Model, a simulation model developed by the US EPA to assist in creating the D/DBP Rules. Additionally, Monte Carlo sampling methods were used to study the impact of uncertainty of influent water quality on WTP decision-making and generate plans for robust WTP performance.

  18. Advancing the adaptive capacity of social-ecological systems to absorb climate extremes

    NASA Astrophysics Data System (ADS)

    Thonicke, Kirsten; Bahn, Michael; Bardgett, Richard; Bloemen, Jasper; Chabay, Ilan; Erb, Karlheinz; Giamberini, Mariasilvia; Gingrich, Simone; Lavorel, Sandra; Liehr, Stefan; Rammig, Anja

    2017-04-01

    The recent and projected increases in climate variability and the frequency of climate extremes are posing a profound challenge to society and the biosphere (IPCC 2012, IPCC 2013). Climate extremes can affect natural and managed ecosystems more severely than gradual warming. The ability of ecosystems to resist and recover from climate extremes is therefore of fundamental importance for society, which strongly relies on their ability to supply provisioning, regulating, supporting and cultural services. Society in turn triggers land-use and management decisions that affect ecosystem properties. Thus, ecological and socio-economic conditions are tightly coupled in what has been referred to as the social-ecological system. For ensuring human well-being in the light of climate extremes it is crucial to enhance the resilience of the social-ecological system (SES) across spatial, temporal and institutional scales. Stakeholders, such as resource managers, urban, landscape and conservation planners, decision-makers in agriculture and forestry, as well as natural hazards managers, require an improved knowledge base for better-informed decision making. To date the vulnerability and adaptive capacity of SESs to climate extremes is not well understood and large uncertainties exist as to the legacies of climate extremes on ecosystems and on related societal structures and processes. Moreover, we lack empirical evidence and incorporation of simulated future ecosystem and societal responses to support pro-active management and enhance social-ecological resilience. In our presentation, we outline the major research gaps and challenges to be addressed for understanding and enhancing the adaptive capacity of SES to absorb and adapt to climate extremes, including acquisition and elaboration of long-term monitoring data and improvement of ecological models to better project climate extreme effects and provide model uncertainties. We highlight scientific challenges and discuss

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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.

  4. 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

  5. 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.

  6. Time of Emergence of Climate Extremes in the Pacific Northwest

    NASA Astrophysics Data System (ADS)

    Lynch, C.; Salathe, E. P., Jr.; Snover, A. K.; Yu, R.

    2014-12-01

    The time at which a climate variable emerges from the noise of climate variability, or "time of emergence" (ToE), is explored from a stakeholder-driven perspective. Using both global and statistically downscaled climate model output from the Coupled Model Intercomparison Project phase 5 (CMIP5) and hydrologic model results, management-relevant measures of the climate and environment are analyzed for the Pacific Northwest (PNW), within the broader context of the continental United States. The specific climate variables were selected through meetings with key regional resource managers at federal, state, and local agencies, and generally relate to exceptional events in temperature, precipitation, and streamflow. Uncertainty in ToE calculations is also examined due to three sources: 1) statistical estimation of emergence 2) future emission scenarios (rcp4.5 and rcp8.5) and 3) multi-model ensemble spread. In the PNW, results show that for temperature related climate variables, ToE is likely within the next 50 years, with a strong positive trend, regardless of emission scenario. Precipitation related variables show a much later ToE, with a weak positive signal despite some model disagreement in direction of change. As this data is intended for socio-economic stakeholders in the PNW, a web tool has been designed to allow for visualizing and analyzing ToE for multiple climate variables and the associated probability statistics across the PNW domain. This information will help guide resource managers in the prioritization and timing of climate change adaption activities.

  7. 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...

  8. 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...

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

    NASA Astrophysics Data System (ADS)

    Cvijanovic, I.; MacMartin, D. G.; Caldeira, K.

    2015-12-01

    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. While our model results imply that ocean albedo alteration does not appear to be an effective way of offsetting the overall effects of CO2 induced global warming or achieving full sea ice recovery, we do not exclude that it may represent a possible approach for small-scale (e.g. individual bay or estuary) sea ice restoration.

  10. 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.

  11. 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

  12. 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

  13. Thermal variability alters the impact of climate warming on consumer-resource systems.

    PubMed

    Fey, Samuel B; Vasseur, David A

    2016-07-01

    Thermal variation through space and time are prominent features of ecosystems that influence processes at multiple levels of biological organization. Yet, it remains unclear how populations embedded within biological communities will respond to climate warming in thermally variable environments, particularly as climate change alters existing patterns of thermal spatial and temporal variability. As environmental temperatures increase above historical ranges, organisms may increasingly rely on extreme habitats to effectively thermoregulate. Such locations desirable in their thermal attributes (e.g., thermal refugia) are often suboptimal for resource acquisition (e.g., underground tunnels). Thus, via the expected increase in both mean temperatures and diel thermal variation, climate warming may heighten the trade-off for consumers between behaviors maximizing thermal performance and those maximizing resource acquisition. Here, we integrate behavioral, physiological, and trophic ecology to provide a general framework for understanding how temporal thermal variation, mediated by access to a thermal refugium, alters the response of consumer-resource systems to warming. We use this framework to predict how temporal variation and access to thermal refugia affect the persistence of consumers and resources during climate warming, how the quality of thermal refugia impact consumer-resource systems, and how consumer-resource systems with fast vs. slow ecological dynamics respond to warming. Our results show that the spatial thermal variability provided by refugia can elevate consumer biomass at warmer temperatures despite reducing the fraction of time consumers spend foraging, that temporal variability detrimentally impacts consumers at high environmental temperatures, and that consumer-resource systems with fast ecological dynamics are most vulnerable to climate warming. Thus, incorporating both estimates of thermal variability and species interactions may be necessary to

  14. Climate Extremes Triggered State Shifting of US Great Plains Prairie under Experimental Warming

    NASA Astrophysics Data System (ADS)

    Luo, Y.; Xu, X.; Sherry, R.; Niu, S.; Li, D.; Xia, J.

    2012-04-01

    Ecosystems can exist under multiple stable states. Transition from one stable state to another is usually triggered by perturbations such as climate extremes, which should be large enough to push the ecosystem over a threshold. Ecosystem state changes can alter ecosystem functions and services as dramatically as in Sahara with vegetation changes from tropical forests to grassland and deserts over 6000 years. Thus it is crucial to understand mechanisms underlying ecosystem state changes. State changes of ecosystem vegetation have been well documented in paleo-records and predicted to occur under climate change by dynamic global vegetation models. Paleo-records usually offer broad-scale patterns of ecosystem state changes over time and rarely offer much insight into fundamental mechanisms underlying the state changes. Model predictions may be calibrated against contemporary and paleo vegetation distributions but have not been carefully tested against experimental evidence. The latter, however, is extremely rare largely because global chance experiments are mostly short term. We have observed state shifting of a US Great Plains prairie under long-term experimental warming and clipping treatments. Our analysis of 11-year data from the experiment showed two-stage stimulations of aboveground net primary production (ANPP) with small increases in the first 7 followed by distinctly large increases under experimental warming in comparison with those under control. The two-stage ANPP simulations were corresponded with species reordering with the plant community over time but not related to warming-induced changes in temperature, soil moisture and nitrogen dynamics in the grassland. The state shifting of the grassland under the experimental warming was partly because our experimental site locates in an ecotone between the mixed and tall grass prairies. Under the experimental warming, the prairie was shifting from the mixed prairie as dominated by Schizachyrium scoparium

  15. 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

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

    USDA-ARS?s Scientific Manuscript database

    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...

  17. On the Edge: the Impact of Climate Change, Climate Extremes, and Climate-driven Disturbances on the Food-Energy-Water Nexus in the Colorado River Basin

    NASA Astrophysics Data System (ADS)

    Bennett, K. E.; McDowell, N. G.; Tidwell, V. C.; Xu, C.; Solander, K.; Jonko, A. K.; Wilson, C. J.; Middleton, R. S.

    2016-12-01

    The Colorado River Basin (CRB) is a critical watershed in terms of vulnerability to climate change and supporting the food-energy-water nexus. Climate-driven disturbances in the CRB—including wildfire, drought, and pests—threaten the watershed's ability to reliably support a wide array of ecosystem services while meeting the interrelated demands of the food-energy-water nexus. Our work illustrates future changes for upper Colorado River headwater basins using the Variable Infiltration Capacity hydrologic model driven by downscaled CMIP5 global climate data coupled with pseudo-dynamic vegetation shifts associated with changing fire and drought conditions. We examine future simulated streamflow within the context of an operational model framework to consider the impacts on water operators and managers who rely upon the timely and continual delivery of streamflow. We focus on results for a large case study basin within the CRB—the San Juan River—showing future scenarios where this ecosystem is pushed towards the extremes. Our findings illustrate that landscape change in the CRB cause delayed snowmelt and increased evapotranspiration from shrublands, which leads to increases in the frequency and magnitude of both droughts and floods within disturbed systems. By 2080, coupled climate and landscape change produces a dramatically altered hydrograph resulting in larger peak flows, reduced lower flows, and lower overall streamflow. Operationally, this results in increased future water delivery challenges and lower reservoir storages driven by changes in the headwater basins. Ultimately, our work shows that the already-stressed CRB ecosystem could, in the future, be pushed over a tipping point, significantly impacting the basin's ability to reliably supply water for food, energy, and urban uses.

  18. 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.

  19. 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.

  20. 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

  1. Competition alters tree growth responses to climate at individual and stand scales

    Treesearch

    Kevin Ford; Ian K. Breckheimer; Jerry F. Franklin; James A. Freund; Steve J. Kroiss; Andrew J. Larson; Elinore J. Theobald; Janneke. HilleRisLambers

    2015-01-01

    Understanding how climate affects tree growth is essential for assessing climate change impacts on forests, but is complicated by the effects of competition, which strongly influences growth and could alter how forests respond to climate change. We characterized the joint effects of climate and competition on diameter growth in the mountain forests of Mount Rainier...

  2. Flood mechanisms and flood extremes in a changing climate

    NASA Astrophysics Data System (ADS)

    Berghuijs, Wouter; Woods, Ross

    2017-04-01

    River flooding can have severe societal, economic and environmental consequences. However, limited understanding of the regional differences in flood-generating mechanisms results in poorly understood historical flood trends and uncertain predictions of future flood conditions. To address this issue, we use a simple observation-based approach to decipher the dominant drivers of floods across large geographic regions. The generated process knowledge provides helpful context of the mechanisms that are of main interest when studying the (non)stationarity of flood response. Such assessments of floods trends across large regions always focus on frequently occurring events (e.g. annual peaks), whereas changes in very extreme but rare floods are only studied for a small number of locations that have exceptionally long observational records. Understanding changes in these extreme and rare floods is especially relevant as these events are often most damaging. Utilizing aggregate regional flood information, we show that during recent decades there is a strong decadal variability and an overall increase in both the frequency and magnitude of extreme floods across multiple continents. This observation-based assessment of extreme floods is broadly consistent with model predictions, but also highlights strong decadal variability. Because we mapped regional differences in flood generating mechanisms of more commonly occurring floods, there remains a need to identify the regional and hemispheric drivers that control changes in extreme floods.

  3. 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

  4. Extreme rainfall events can alter inter-annual biomass responses to water and N enrichment

    NASA Astrophysics Data System (ADS)

    Kong, D. L.; Lü, X. T.; Jiang, L. L.; Wu, H. F.; Miao, Y.; Kardol, P.

    2013-12-01

    Water availability has profound effects on plant growth and productivity in temperate and semiarid grasslands. However, it remains unclear how variation of inter-annual precipitation by extreme rainfall events will alter the aboveground and belowground responses of plants, and how these responses may be contingent on N availability. In this study, we examined the interactive effects of inter-annual precipitation variation and N addition on aboveground and live fine root biomass of a semiarid grassland in northern China for two consecutive years (2007 and 2008). Inter-annual variation in precipitation resulting mainly from the occurrence of extreme rainfall events in 2008 significantly affected above- and belowground plant biomass responses to water addition. In addition, variation of inter-annual precipitation by this extreme rainfall event suppressed plant responses to nitrogen addition and reduced the interaction effects between water and nitrogen addition. These effects of inter-annual precipitation fluctuation could be attributed to the negative influence of the extreme rainfall event on soil N and water availability, ultimately reducing plant rainfall use efficiency and nitrogen use efficiency. In conclusion, our results suggest ecosystem responses to water and N enrichment could be altered by inter-annual variation of precipitation regime caused by the naturally occurring extreme rainfall events.

  5. 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.

  6. 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

  7. Temperature extremes and health: impacts of climate variability and change in the United States.

    PubMed

    O'Neill, Marie S; Ebi, Kristie L

    2009-01-01

    We evaluated temperature-related morbidity and mortality for the 2007 U.S. national assessment on impacts of climate change and variability on human health. We assessed literature published since the 2000 national assessment, evaluating epidemiologic studies, surveys, and studies projecting future impacts. Under current climate change projections, heat waves and hot weather are likely to increase in frequency, with the overall temperature distribution shifting away from the colder extremes. Vulnerable subgroups include communities in the northeastern and Midwestern U.S.; urban populations, the poor, the elderly, children, and those with impaired health or limited mobility. Temperature extremes and variability will remain important determinants of health in the United States under climate change. Research needs include estimating exposure to temperature extremes; studying nonfatal temperature-related illness; uniform criteria for reporting heat-related health outcomes; and improving effectiveness of urban heat island reduction and extreme weather response plans.

  8. Time-varying extreme rainfall intensity-duration-frequency curves in a changing climate

    NASA Astrophysics Data System (ADS)

    Sarhadi, Ali; Soulis, Eric D.

    2017-03-01

    Anthropogenic climate change influences the nature and probabilistic behavior of extreme climate phenomena over time. Current infrastructure design of water systems, however, is based on intensity-duration-frequency (IDF) curves that assume extreme precipitation will not significantly change. To sustain the reliability of infrastructure designs in a changing environment, time-varying nonstationary-based IDF curves must replace the static stationary-based IDF curves. This study outlines a fully time varying risk framework using Bayesian Markov chain Monte Carlo techniques to incorporate the impact of different complex nonstationary conditions on the occurrence of extreme precipitation in the Great Lakes area. The results demonstrate the underestimation of the extreme precipitation using stationary assumptions and the importance of updating infrastructure design strategies in a changing climate.

  9. 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

  10. 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

  11. Climatic extreme indices over South America: validation and projections from the Eta RCM

    NASA Astrophysics Data System (ADS)

    Chou, Sin-Chan; de Arruda Lyra, André; Chagas, Diego; Dereczynski, Claudine; Sondermann, Marcely; Regoto, Pedro; Tavares, Priscila

    2017-04-01

    The assessment of the changes of the climatic extreme indices are useful to support impact, vulnerability, and adaptation studies of climate change. Output from global climate models are generally smooth due to the coarse horizontal resolution, generally of a few hundreds of kilometers. The dynamical downscaling of global climate models can reach resolutions of a few kilometers. Regional Climate Model can provide more detail of the underlying surface such as vegetation, topography, etc. In addition, smaller grid size of RCMs allows stronger horizontal gradients and consequently stronger events. Therefore, extreme climatic events are better reproduced at higher resolution. The Eta Regional Climate Model was set up in 20-km resolution over South America to downscale the climate change projections produced by three global climate models, HadGEM2-ES, MIROC5, and Can-ESM, under RCP4.5 and RCP8.5 scenarios. The objective of this work is to assess the changes in the climatic extreme indices over South America. The runs start on 1960 and end in 2100. The baseline period is taken from 1961 until 1990, whereas the projections are shown in three timeslices of thirty years, 2011-2040, 2041-2070, and 2071-2100. Initially, a validation of the indices are carried out by comparing the trends from the three downscaling simulations against the observed trends. The trends of the indices related to temperature extremes are generally well reproduced by the three simulations in the baseline period, whereas the trends related to precipitation extreme indices show that the Eta model run driven by Can-ESM reproduce better the trends. The projections show some mixed trends in the precipitation extremes in some regions. For example, in the western Amazonia and in parts of Southeast Brazil, although the total annual precipitation tends to decrease in all projections, the 99th percentile show increase in the future times slices. The projections of warming trend in the temperature extreme

  12. Non-stationarity of climate extremes: Natural variability and Anthropogenic forcings

    NASA Astrophysics Data System (ADS)

    Mahajan, S.; Evans, K. J.; Branstetter, M. L.; Kovilakam, M.

    2016-12-01

    Climate extremes are the most tangible of societal and economic impacts of climate, warranting a better understanding and quantification of their changing behavior. We analyze the trends and tele-connections of precipitation extremes in a small ensemble (4 realizations) of high-resolution simulations (from the Accelerated Climate Modeling Project [ACME]) and a large ensemble (40 realizations) of low-resolution simulations (from the Community Earth System Model Large Ensemble Project [LENS]). A regionalization framework is applied to improve the sample size of extreme events by using data from neighboring regions with a homogeneous climate. The generalized extreme value theory is used to quantify the statistics and non-stationary behavior of precipitation extremes. The LENS simulations reveal that the trend in the twentieth century is significant in several regions of the world, but the trends are not robust across the simulation ensemble. However, the twenty-first century projections in those simulations forced with RCP 8.5 emissions exhibit a robust increasing trend across the ensemble, suggesting that while natural variability dictated variability of precipitation extremes in the past century, anthropogenic forcing would most likely dominate the variability in the future. Single forcing runs with excessive black carbon aerosol concentrations - replicating nuclear winter scenarios - also suggest a role for aerosols in modulating climate extremes. The computational expense of high-resolution model configurations currently limits the length of the simulation period. ACME baseline high-resolution runs were integrated for the period 1979-2005. We find that such a short duration is not enough to capture trends in precipitation extremes in the observations and thus short high-resolution simulations cannot be properly validated for such trends. However, the high-resolution models are able to improve the simulation of tele-connections of extremes with low

  13. 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.

  14. 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.

  15. Characterizing differences in precipitation regimes of extreme wet and dry years: implications for climate change experiments.

    PubMed

    Knapp, Alan K; Hoover, David L; Wilcox, Kevin R; Avolio, Meghan L; Koerner, Sally E; La Pierre, Kimberly J; Loik, Michael E; Luo, Yiqi; Sala, Osvaldo E; Smith, Melinda D

    2015-02-03

    Climate change is intensifying the hydrologic cycle and is expected to increase the frequency of extreme wet and dry years. Beyond precipitation amount, extreme wet and dry years may differ in other ways, such as the number of precipitation events, event size, and the time between events. We assessed 1614 long-term (100 year) precipitation records from around the world to identify key attributes of precipitation regimes, besides amount, that distinguish statistically extreme wet from extreme dry years. In general, in regions where mean annual precipitation (MAP) exceeded 1000 mm, precipitation amounts in extreme wet and dry years differed from average years by ~40% and 30%, respectively. The magnitude of these deviations increased to >60% for dry years and to >150% for wet years in arid regions (MAP<500 mm). Extreme wet years were primarily distinguished from average and extreme dry years by the presence of multiple extreme (large) daily precipitation events (events >99th percentile of all events); these occurred twice as often in extreme wet years compared to average years. In contrast, these large precipitation events were rare in extreme dry years. Less important for distinguishing extreme wet from dry years were mean event size and frequency, or the number of dry days between events. However, extreme dry years were distinguished from average years by an increase in the number of dry days between events. These precipitation regime attributes consistently differed between extreme wet and dry years across 12 major terrestrial ecoregions from around the world, from deserts to the tropics. Thus, we recommend that climate change experiments and model simulations incorporate these differences in key precipitation regime attributes, as well as amount into treatments. This will allow experiments to more realistically simulate extreme precipitation years and more accurately assess the ecological consequences. © 2015 John Wiley & Sons Ltd.

  16. 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

  17. 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

  18. 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.

  19. Phenological Implications of Warming Temperatures and Extreme Climatic Events

    NASA Astrophysics Data System (ADS)

    Schwartz, Mark D.; Enquist, Carolyn A. F.; Denny, Ellen G.

    2013-03-01

    More than 140 phenology researchers traveled from 6 continents and 21 countries to convene and deliver more than 100 oral presentations and more than 30 posters at the University of Wisconsin-Milwaukee School of Continuing Education Conference Center in downtown Milwaukee at the second interdisciplinary international conference on phenology. The study of recurring plant and animal life-cycle stages, phenology is especially sensitive to variation and change in the environment and climate.

  20. 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).

  1. Assessing Future Projections of Climate Extremes Over the South Central USA

    NASA Astrophysics Data System (ADS)

    Gillson, D. L.; Rosendahl, D. H.; Mullens, E.

    2016-12-01

    Climate extremes (heavy precipitation, drought, heat waves, storms, etc.) can have an adverse effect on several aspects of life including infrastructure, economy, agriculture, and ecosystems. Understanding observed extremes events in the past and being able to determine how well climate models capture these will help to anticipate and plan for the future. The Expert Team on Climate Change and Detection (ETCCDI) have defined and developed a list of 27 core climate extreme indices that measure temperature and precipitation. Previous studied have compared the reliability of global reanalyses in a variety of regions but very few (if any) have done so in the south central USA. This study uses 11 of the climate extreme indices with available monthly data to analyze climate extremes from historical observation-based reanalyses (ERA40, ERA-Interim, NCEP1, NCEP2) as well as historical and future projections of 31 global climate models (GCMs) from the Couple Model Intercomparison Project Phase 5 (CMIP5). We split the south central region into three sub-regions (west central, south central and east central). Results indicated that observation-based reanalyses can be significantly different from one another and therefore result in varying model biases depending on which is used. Model performance is dependent on region, season, and extreme indices, and therefore no single model was found to be best for all situations. Similar models from the same institutions tend to contain similar biases within and across regions. This study also provides future projections that show a possible differentiation between the best and worst performing models.

  2. 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.

  3. Development and assessment of indices to determine stream fish vulnerability to climate change and habitat alteration

    USGS Publications Warehouse

    Sievert, Nicholas A.; Paukert, Craig P.; Tsang, Yin-Phan; Infante, Dana M.

    2016-01-01

    Understanding the future impacts of climate and land use change are critical for long-term biodiversity conservation. We developed and compared two indices to assess the vulnerability of stream fish in Missouri, USA based on species environmental tolerances, rarity, range size, dispersal ability and on the average connectivity of the streams occupied by each species. These two indices differed in how environmental tolerance was classified (i.e., vulnerability to habitat alteration, changes in stream temperature, and changes to flow regimes). Environmental tolerance was classified based on measured species responses to habitat alteration, and extremes in stream temperatures and flow conditions for one index, while environmental tolerance for the second index was based on species’ traits. The indices were compared to determine if vulnerability scores differed by index or state listing status. We also evaluated the spatial distribution of species classified as vulnerable to habitat alteration, changes in stream temperature, and change in flow regimes. Vulnerability scores were calculated for all 133 species with the trait association index, while only 101 species were evaluated using the species response index, because 32 species lacked data to analyze for a response. Scores from the trait association index were greater than the species response index. This is likely due to the species response index's inability to evaluate many rare species, which generally had high vulnerability scores for the trait association index. The indices were consistent in classifying vulnerability to habitat alteration, but varied in their classification of vulnerability due to increases in stream temperature and alterations to flow regimes, likely because extremes in current climate may not fully capture future conditions and their influence on stream fish communities. Both indices showed higher mean vulnerability scores for listed species than unlisted species, which provided a coarse

  4. Sensitivity of UK butterflies to local climatic extremes: which life stages are most at risk?

    PubMed

    McDermott Long, Osgur; Warren, Rachel; Price, Jeff; Brereton, Tom M; Botham, Marc S; Franco, Aldina M A

    2017-01-01

    There is growing recognition as to the importance of extreme climatic events (ECEs) in determining changes in species populations. In fact, it is often the extent of climate variability that determines a population's ability to persist at a given site. This study examined the impact of ECEs on the resident UK butterfly species (n = 41) over a 37-year period. The study investigated the sensitivity of butterflies to four extremes (drought, extreme precipitation, extreme heat and extreme cold), identified at the site level, across each species' life stages. Variations in the vulnerability of butterflies at the site level were also compared based on three life-history traits (voltinism, habitat requirement and range). This is the first study to examine the effects of ECEs at the site level across all life stages of a butterfly, identifying sensitive life stages and unravelling the role life-history traits play in species sensitivity to ECEs. Butterfly population changes were found to be primarily driven by temperature extremes. Extreme heat was detrimental during overwintering periods and beneficial during adult periods and extreme cold had opposite impacts on both of these life stages. Previously undocumented detrimental effects were identified for extreme precipitation during the pupal life stage for univoltine species. Generalists were found to have significantly more negative associations with ECEs than specialists. With future projections of warmer, wetter winters and more severe weather events, UK butterflies could come under severe pressure given the findings of this study.

  5. 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.

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

    PubMed

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

    2014-10-31

    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" δ(13)C 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 δ(18)O 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.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. Optimal adaptation to extreme rainfalls under climate change

    NASA Astrophysics Data System (ADS)

    Rosbjerg, Dan

    2017-04-01

    More intense and frequent rainfalls have increased the number of urban flooding events in recent years, prompting adaptation efforts. Economic optimization is considered an efficient tool to decide on the design level for adaptation. The costs associated with a flooding to the T-year level and the annual capital and operational costs of adapting to this level are described with log-linear relations. The total flooding costs are developed as the expected annual damage of flooding above the T-year level plus the annual capital and operational costs for ensuring no flooding below the T-year level. The value of the return period T that corresponds to the minimum of the sum of these costs will then be the optimal adaptation level. The change in climate, however, is expected to continue in the next century, which calls for expansion of the above model. The change can be expressed in terms of a climate factor (the ratio between the future and the current design level) which is assumed to increase in time. This implies increasing costs of flooding in the future for many places in the world. The optimal adaptation level is found for immediate as well as for delayed adaptation. In these cases the optimum is determined by considering the net present value of the incurred costs during a sufficiently long time span. Immediate as well as delayed adaptation is considered.

  13. Optimal adaptation to extreme rainfalls in current and future climate

    NASA Astrophysics Data System (ADS)

    Rosbjerg, Dan

    2017-01-01

    More intense and frequent rainfalls have increased the number of urban flooding events in recent years, prompting adaptation efforts. Economic optimization is considered an efficient tool to decide on the design level for adaptation. The costs associated with a flooding to the T-year level and the annual capital and operational costs of adapting to this level are described with log-linear relations. The total flooding costs are developed as the expected annual damage of flooding above the T-year level plus the annual capital and operational costs for ensuring no flooding below the T-year level. The value of the return period T that corresponds to the minimum of the sum of these costs will then be the optimal adaptation level. The change in climate, however, is expected to continue in the next century, which calls for expansion of the above model. The change can be expressed in terms of a climate factor (the ratio between the future and the current design level) which is assumed to increase in time. This implies increasing costs of flooding in the future for many places in the world. The optimal adaptation level is found for immediate as well as for delayed adaptation. In these cases, the optimum is determined by considering the net present value of the incurred costs during a sufficiently long time-span. Immediate as well as delayed adaptation is considered.

  14. Evolution of precipitation extremes in two large ensembles of climate simulations

    NASA Astrophysics Data System (ADS)

    Martel, Jean-Luc; Mailhot, Alain; Talbot, Guillaume; Brissette, François; Ludwig, Ralf; Frigon, Anne; Leduc, Martin; Turcotte, Richard

    2017-04-01

    Recent studies project significant changes in the future distribution of precipitation extremes due to global warming. It is likely that extreme precipitation intensity will increase in a future climate and that extreme events will be more frequent. In this work, annual maxima daily precipitation series from the Canadian Earth System Model (CanESM2) 50-member large ensemble (spatial resolution of 2.8°x2.8°) and the Community Earth System Model (CESM1) 40-member large ensemble (spatial resolution of 1°x1°) are used to investigate extreme precipitation over the historical (1980-2010) and future (2070-2100) periods. The use of these ensembles results in respectively 1 500 (30 years x 50 members) and 1200 (30 years x 40 members) simulated years over both the historical and future periods. These large datasets allow the computation of empirical daily extreme precipitation quantiles for large return periods. Using the CanESM2 and CESM1 large ensembles, extreme daily precipitation with return periods ranging from 2 to 100 years are computed in historical and future periods to assess the impact of climate change. Results indicate that daily precipitation extremes generally increase in the future over most land grid points and that these increases will also impact the 100-year extreme daily precipitation. Considering that many public infrastructures have lifespans exceeding 75 years, the increase in extremes has important implications on service levels of water infrastructures and public safety. Estimated increases in precipitation associated to very extreme precipitation events (e.g. 100 years) will drastically change the likelihood of flooding and their extent in future climate. These results, although interesting, need to be extended to sub-daily durations, relevant for urban flooding protection and urban infrastructure design (e.g. sewer networks, culverts). Models and simulations at finer spatial and temporal resolution are therefore needed.

  15. Know your limits? Climate extremes impact the range of Scots pine in unexpected places

    PubMed Central

    Julio Camarero, J.; Gazol, Antonio; Sancho-Benages, Santiago; Sangüesa-Barreda, Gabriel

    2015-01-01

    Background and Aims Although extreme climatic events such as drought are known to modify forest dynamics by triggering tree dieback, the impact of extreme cold events, especially at the low-latitude margin (‘rear edge’) of species distributional ranges, has received little attention. The aim of this study was to examine the impact of one such extreme cold event on a population of Scots pine (Pinus sylvestris) along the species’ European southern rear-edge range limit and to determine how such events can be incorporated into species distribution models (SDMs). Methods A combination of dendrochronology and field observation was used to quantify how an extreme cold event in 2001 in eastern Spain affected growth, needle loss and mortality of Scots pine. Long-term European climatic data sets were used to contextualize the severity of the 2001 event, and an SDM for Scots pine in Europe was used to predict climatic range limits. Key Results The 2001 winter reached record minimum temperatures (equivalent to the maximum European-wide diurnal ranges) and, for trees already stressed by a preceding dry summer and autumn, this caused dieback and large-scale mortality. Needle loss and mortality were particularly evident in south-facing sites, where post-event recovery was greatly reduced. The SDM predicted European Scots pine distribution mainly on the basis of responses to maximum and minimum monthly temperatures, but in comparison with this the observed effects of the 2001 cold event at the southerly edge of the range limit were unforeseen. Conclusions The results suggest that in order to better forecast how anthropogenic climate change might affect future forest distributions, distribution modelling techniques such as SDMs must incorporate climatic extremes. For Scots pine, this study shows that the effects of cold extremes should be included across the entire distribution margin, including the southern ‘rear edge’, in order to avoid biased predictions based solely

  16. Transformation of soil organics under extreme climate events: a project description

    NASA Astrophysics Data System (ADS)

    Blagodatskaya, Evgenia

    2017-04-01

    Recent climate scenarios predict not only continued global warming but also an increased frequency and intensity of extreme climatic events such as strong changes in temperature and precipitation with unusual regional dynamics. Weather anomalies at European territory of Russia are currently revealed as long-term drought and strong showers in summer and as an increased frequency of soil freezing-thawing cycles. Climate extremes totally change biogeochemical processes and elements cycling both at the ecosystem level and at the level of soil profile mainly affecting soil biota. Misbalance in these processes can cause a reduction of soil carbon stock and an increase of greenhouse gases emission. Our project aims to reveal the transformation mechanisms of soil organic matter caused by extreme weather events taking into consideration the role of biotic-abiotic interactions in regulation of formation, maintenance and turnover of soil carbon stock. Our research strategy is based on the novel concept considering extreme climatic events (showers after long-term droughts, soil flooding, freezing-thawing) as abiotic factors initiating a microbial succession. Study on stoichiometric flexibility of plants under climate extremes as well as on resulting response of soil heterotrophs on stoichiometric changes in substrate will be used for experimental prove and further development of the theory of ecological stoichiometry. The results enable us to reveal the mechanisms of biotic - abiotic interactions responsible for the balance between mobilization and stabilization of soil organic matter. Identified mechanisms will form the basis of an ecosystem model enabled to predict the effects of extreme climatic events on biogenic carbon cycle in the biosphere.

  17. Temporal and spatial variations in hydro-climatic extremes in the Lake Victoria basin

    NASA Astrophysics Data System (ADS)

    Mbungu, W.; Ntegeka, V.; Kahimba, F. C.; Taye, M.; Willems, P.

    A study was carried out to investigate variability in long term hydro-climatic extremes in the Lake Victoria basin, East Africa. The study aimed at determining whether the long term historical changes in frequency and magnitude of hydro-climatic extremes are statistically significant, to give more light on the differentiation of climate variability from climate change. Long term extremes for 22 rainfall and 10 river flow gauge stations were examined. The hydro-climatic extremes were aggregated at levels from daily, decadal, to monthly scales defined for two wet seasons in the area, the long rainy season extending from March to May (MAM) and the short rainy season extending from October to December (OND), and time slices of 10 years using a sliding window approach. An empirical statistical technique based on Quantile Perturbation Method (QPM) was used. Quantile perturbations that represent empirical changes for precipitation and river flow extremes were derived. Significant decreasing trends in precipitation were observed in the 1930s, 1970s and 1980s, while significant increasing trends were common in the 1960s, late 1980s, and 1990s to the most recent years (2000-2006). In general, significant trends were dominant in the OND compared to MAM season for precipitation and river flow extremes. Results indicated further that there are differences in geographic location of significant trends in the hydro-climatic variables investigated implying that impacts are not spatially coherent. Areas with significant trends appeared to be concentrated in the North to North eastern parts compared to those in the southern parts of the basin.

  18. Variability in winter climate and winter extremes reduces population growth of an alpine butterfly.

    PubMed

    Roland, Jens; Matter, Stephen F

    2013-01-01

    We examined the long-term, 15-year pattern of population change in a network of 21 Rocky Mountain populations of Parnassius smintheus butterflies in response to climatic variation. We found that winter values of the broadscale climate variable, the Pacific Decadal Oscillation (PDO) index, were a strong predictor of annual population growth, much more so than were endogenous biotic factors related to population density. The relationship between PDO and population growth was nonlinear. Populations declined in years with extreme winter PDO values, when there were either extremely warm or extremely cold sea surface temperatures in the eastern Pacific relative to that in the western Pacific. Results suggest that more variable winters, and more frequent extremely cold or warm winters, will result in more frequent decline of these populations, a pattern exacerbated by the trend for increasingly variable winters seen over the past century.

  19. Large-scale drivers of local precipitation extremes in convection-permitting climate simulations

    NASA Astrophysics Data System (ADS)

    Chan, Steven C.; Kendon, Elizabeth J.; Roberts, Nigel M.; Fowler, Hayley J.; Blenkinsop, Stephen

    2016-04-01

    The Met Office 1.5-km UKV convective-permitting models (CPM) is used to downscale present-climate and RCP8.5 60-km HadGEM3 GCM simulations. Extreme UK hourly precipitation intensities increase with local near-surface temperatures and humidity; for temperature, the simulated increase rate for the present-climate simulation is about 6.5% K**-1, which is consistent with observations and theoretical expectations. While extreme intensities are higher in the RCP8.5 simulation as higher temperatures are sampled, there is a decline at the highest temperatures due to circulation and relative humidity changes. Extending the analysis to the broader synoptic scale, it is found that circulation patterns, as diagnosed by MSLP or circulation type, play an increased role in the probability of extreme precipitation in the RCP8.5 simulation. Nevertheless for both CPM simulations, vertical instability is the principal driver for extreme precipitation.

  20. 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.

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

    NASA Astrophysics Data System (ADS)

    Zarekarizi, Mahkameh; Rana, Arun; Moradkhani, Hamid

    2017-09-01

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

  2. Impacts of climate extremes on gross primary productivity of terrestrial ecosystems in conterminous USA

    NASA Astrophysics Data System (ADS)

    Wu, X.; Xiao, X.; Zhang, Y.; Zhang, G.

    2016-12-01

    By offsetting one-third of anthropogenic carbon emissions, terrestrial carbon uptake mitigates atmospheric CO2 concentration and consequent global warming. However, the current global warming trend is inducing more climate extremes, which in turn cause large changes in terrestrial carbon uptake. Here we report the seasonal and regional anomalies of gross primary productivity (GPP) across the conterminous USA (CONUS) in response to two contrasting climate extremes: the cool and wet 2009 versus the warm and dry 2012. We used the Vegetation Photosynthesis Model (VPM, Xiao et al., 2006), MODIS images and NCEP/NARR climate data to estimate GPP from 2009-2014, and evaluated the VPM-predicted GPP with the estimated GPP from the CO2 eddy flux tower sites (24 sites). We analyze the correlation between the anomalies of the continental GPP and the anomalies of temperature and precipitation. The results show a substantial, negative GPP anomaly in 2009, in addition to the positive GPP anomaly in 2012, which was already reported in a previous study (Wolf et al., 2016). We also found that GPP anomalies of different climate regions in four seasons are controlled by either temperature or precipitation. Our study shows the robustness of the VPM to simulate GPP under the condition of climate extremes, and highlights the need of investigating the impacts of cooling events on the terrestrial carbon cycle. Our finding also suggests that there is no uniform pattern for terrestrial ecosystems responding to climate extremes, and that climate extremes should be studied in a case-by-case, location-based approach.

  3. 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.

  4. 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.

  5. On the use of self-organizing maps for studying climate extremes

    NASA Astrophysics Data System (ADS)

    Gibson, Peter B.; Perkins-Kirkpatrick, Sarah E.; Uotila, Petteri; Pepler, Acacia S.; Alexander, Lisa V.

    2017-04-01

    Understanding how climate extremes are sensitive to a changing climate requires characterization of the physical mechanisms behind such events. For this purpose, the application of self-organizing maps (SOMs) has become popular in the climate science literature. One potential drawback, though not unique to SOMs, is that the background synoptic conditions represented by SOMs may be too generalized to adequately describe the atypical conditions that can co-occur during the extreme event being considered. In this paper, using the Australian region as a case study, we illustrate how the commonly used SOM training procedure can be readily modified to produce both more accurate patterns and patterns that would otherwise occur too rarely to be represented in the SOM. Even with these improvements, we illustrate that without careful treatment, the synoptic conditions that co-occur during some types of extreme events (i.e., heavy rainfall and midlatitudinal cyclone occurrence days) risk being poorly represented by the SOM patterns. In contrast, we find that during Australian heat wave events the circulation is indeed well represented by the SOM patterns and that this application can provide additional insight to composite analysis. While these results should not necessarily discourage researchers seeking to apply SOMs to study climate extremes, they highlight the importance of first critically evaluating the features represented by the SOM. This study has provided a methodological framework for such an evaluation which is directly applicable to other weather typing procedures, regions, and types of extreme events.

  6. Detection of photosynthetic responses of cool-temperate forests following extreme climate events using Bayesian inversion

    NASA Astrophysics Data System (ADS)

    Toda, M.; Knohl, A.; Herbst, M.; Keenan, T. F.; Yokozawa, M.

    2016-12-01

    The increase in extreme climate events associated with ongoing global warming may create severe damage to terrestrial ecosystems, changing plant structure and the eco-physiological functions that regulate ecosystem carbon exchange. However, most damage is usually due to moderate, rather than catastrophic, disturbances. The nature of plant functional responses to such disturbances, and the resulting effects on the terrestrial carbon cycle, remain poorly understood. To unravel the scientific question, tower-based eddy covariance data in the cool-temperate forests were used to constrain plant eco-physiological parameters in a persimoneous ecosystem model that may have affected carbon dynamics following extreme climate events using the statistic Bayesian inversion approach. In the present study, we raised two types of extreme events relevant for cool-temperate regions, i.e. a typhoon with mechanistic foliage destraction and a heat wave with severe drought. With appropriate evaluation of parameter and predictive uncertainties, the inversion analysis shows annual trajectory of activated photosynthetic responses following climate extremes compared the pre-disturbance state in each forest. We address that forests with moderate disturbance show substantial and rapid photosynthetic recovery, enhanced productivity, and, thus, ecosystem carbon exchange, although the effect of extreme climatic events varies depending on the stand successional phase and the type, intensity, timing and legacy of the disturbance.

  7. 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.

  8. Means and extremes: building variability into community-level climate change experiments.

    PubMed

    Thompson, Ross M; Beardall, John; Beringer, Jason; Grace, Mike; Sardina, Paula

    2013-06-01

    Experimental studies assessing climatic effects on ecological communities have typically applied static warming treatments. Although these studies have been informative, they have usually failed to incorporate either current or predicted future, patterns of variability. Future climates are likely to include extreme events which have greater impacts on ecological systems than changes in means alone. Here, we review the studies which have used experiments to assess impacts of temperature on marine, freshwater and terrestrial communities, and classify them into a set of 'generations' based on how they incorporate variability. The majority of studies have failed to incorporate extreme events. In terrestrial ecosystems in particular, experimental treatments have reduced temperature variability, when most climate models predict increased variability. Marine studies have tended to not concentrate on changes in variability, likely in part because the thermal mass of oceans will moderate variation. In freshwaters, climate change experiments have a much shorter history than in the other ecosystems, and have tended to take a relatively simple approach. We propose a new 'generation' of climate change experiments using down-scaled climate models which incorporate predicted changes in climatic variability, and describe a process for generating data which can be applied as experimental climate change treatments. © 2013 John Wiley & Sons Ltd/CNRS.

  9. 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.

  10. Overview and Update of the North America Drought Monitor and North America Climate Extremes Monitoring System

    NASA Astrophysics Data System (ADS)

    Heim, R. R.

    2006-12-01

    The North America Drought Monitor (NADM) is a joint operational drought monitoring activity between scientists and other specialists in the United States, Mexico, and Canada. Like all weather phenomena, drought occurs irrespective of political and international boundaries. The monthly map and narrative product created by this first-of-its-kind effort provides an integrated continental-scale drought assessment tool for decision-makers in all three countries involved in drought monitoring, drought mitigation, and related climate services. The product is prepared by a rotating primary author who utilizes drought indicators which are computed using standard methodologies for stations across the continent, plus national drought monitoring products and feedback from local experts in each of the three countries. The participants include, within the United States: the NOAA National Climatic Data Center, NOAA Climate Prediction Center, USDA Joint Agricultural Weather Facility, and National Drought Mitigation Center; within Mexico: Servicio Meteorologico Nacional/Comision Nacional del Agua; and within Canada: Agriculture and Agrifood Canada and the Meteorological Service of Canada. The NADM is part of a North America Climate Extremes Monitoring (NACEM) system which will monitor and assess climate extremes across the continent. Several climate indicators are currently computed from station daily data to measure (in addition to drought) heavy precipitation, heat waves, and cold waves. Future efforts will add indicators to monitor storm severity and severe weather, including the creation of a North America Climate Extremes Index (NACEI) patterned after the U.S. Climate Extremes Index (USCEI). This presentation will review the history of the NADM/NACEM effort, the data utilized, the indicators computed, and the product preparation and peer review process.

  11. 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.

  12. How do the multiple large-scale climate oscillations trigger extreme precipitation?

    NASA Astrophysics Data System (ADS)

    Shi, Pengfei; Yang, Tao; Xu, Chong-Yu; Yong, Bin; Shao, Quanxi; Li, Zhenya; Wang, Xiaoyan; Zhou, Xudong; Li, Shu

    2017-10-01

    Identifying the links between variations in large-scale climate patterns and precipitation is of tremendous assistance in characterizing surplus or deficit of precipitation, which is especially important for evaluation of local water resources and ecosystems in semi-humid and semi-arid regions. Restricted by current limited knowledge on underlying mechanisms, statistical correlation methods are often used rather than physical based model to characterize the connections. Nevertheless, available correlation methods are generally unable to reveal the interactions among a wide range of climate oscillations and associated effects on precipitation, especially on extreme precipitation. In this work, a probabilistic analysis approach by means of a state-of-the-art Copula-based joint probability distribution is developed to characterize the aggregated behaviors for large-scale climate patterns and their connections to precipitation. This method is employed to identify the complex connections between climate patterns (Atlantic Multidecadal Oscillation (AMO), El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO)) and seasonal precipitation over a typical semi-humid and semi-arid region, the Haihe River Basin in China. Results show that the interactions among multiple climate oscillations are non-uniform in most seasons and phases. Certain joint extreme phases can significantly trigger extreme precipitation (flood and drought) owing to the amplification effect among climate oscillations.

  13. Mitigation of Regional Temperature Extremes with Climate-Effective Land Management

    NASA Astrophysics Data System (ADS)

    Hirsch, Annette; Wilhelm, Micah; Davin, Edouard; Thiery, Wim; Seneviratne, Sonia

    2017-04-01

    Limiting global warming to well below 2 ˚C is an imminent challenge for humanity. However even if this global target can be met, some regions are still likely to experience substantial warming relative to others. Using idealized global climate simulations we examine the potential of land management options in affecting regional climate, with a focus on crop albedo enhancement and irrigation (Climate-effective Land Management). The implementation is performed over all crop regions globally to provide an upper bound. We find that the implementation of both crop albedo enhancement and irrigation can reduce hot temperature extremes by more than 2 ˚C in North America, Eurasia and India over the 21st century relative to a scenario without management application. The efficacy of crop albedo enhancement scales linearly with the magnitude, where a cooling response exceeding 0.5 ˚C was achieved with a large (i.e. ≥ 0.08) change in land surface albedo. We use a surface energy balance decomposition to evaluate regional differences in the response of temperature extremes to Climate-effective Land Management. Regional differences were attributed to the surface energy balance response with temperature changes mostly explained by latent heat flux changes for irrigation and net shortwave radiation changes for crop albedo enhancement. Our results overall demonstrate that regional warming of hot extremes in our climate model can be partially mitigated when using an idealized treatment of Climate-effective Land Management.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. Anticipating Future Extreme Climate Events for Alaska Using Dynamical Downscaling and Quantile Mapping

    NASA Astrophysics Data System (ADS)

    Lader, R.; Walsh, J. E.

    2016-12-01

    Alaska is projected to experience major changes in extreme climate during the 21st century, due to greenhouse warming and exacerbated by polar amplification, wherein the Arctic is warming at twice the rate compared to the Northern Hemisphere. Given its complex topography, Alaska displays extreme gradients of temperature and precipitation. However, global climate models (GCMs), which typically have a spatial resolution on the order of 100km, struggle to replicate these extremes. To help resolve this issue, this study employs dynamically downscaled regional climate simulations and quantile-mapping methodologies to provide a full suite of daily model variables at 20 km spatial resolution for Alaska, from 1970 to 2100. These data include downscaled products of the: ERA-Interim reanalysis from 1979 to 2015, GFDL-CM3 historical from 1970 to 2005, and GFDL-CM3 RCP 8.5 from 2006 to 2100. Due to the limited nature of long-term observations and high-resolution modeling in Alaska, these data enable a broad expansion of extremes analysis. This study uses these data to highlight a subset of the 27 climate extremes indices, previously defined by the Expert Team on Climate Change Detection and Indices, as they pertain to climate change in Alaska. These indices are based on the statistical distributions of daily surface temperature and precipitation and focus on threshold exceedance, and percentiles. For example, the annual number of days with a daily maximum temperature greater than 25°C is anticipated to triple in many locations in Alaska by the end of the century. Climate extremes can also refer to long duration events, such as the record-setting warmth that defined the 2015-16 cold season in Alaska. The downscaled climate model simulations indicate that this past winter will be considered normal by as early as the mid-2040s, if we continue to warm according to the business-as-usual RCP 8.5 emissions scenario. This represents an accelerated warming as compared to projections

  19. Impact of Extreme Climatic Events on the Temperature Regimes in Urban Streams

    NASA Astrophysics Data System (ADS)

    Parchem, C.; Stewart, I. T.

    2016-12-01

    Urban streams provide important aquatic and riparian habitat close to population centers, as well as other ecosystem services such as flood protection, storm water drainage and recreational functions. Yet, they are already greatly impacted by human action through water management, channel modifications, destruction of riparian habitat, and pollution. This has potentially rendered them more vulnerable to the climatic extremes projected from climatic changes. From 2012 - 2016, California has experienced to date the most severe drought since the beginning of weather recordings. The combination of the resulting extremely low stream flows exacerbated by low precipitation, high evaporation rates, and greater human demand on water, with high temperature have increased the temperature regime in urban streams. However, the extent to which urban stream temperatures are impacted by extreme climatic conditions and what role stream morphology, stream flow characteristics, and riparian vegetation play, are not sufficiently understood. For this project, we monitored stream temperature, dissolved oxygen, and flow depth along a network of 18 sites in the Los Gatos Creek, Guadalupe River, and Coyote Creek, located in the urban regions of the southern San Francisco Bay Area. Monitoring sites were distributed from stream headwaters to flood plains and represented a variety of stream environments. We examined the variation in stream temperature and dissolved oxygen with extreme air temperature, extremely low flow conditions, riparian shading, and channel morphology. Our results show that during the recent drought, hourly stream temperatures rose up to 34°C during summer heat waves for sites in the lower stream reaches without riparian shading. By contrast, shaded sites with deeper flows, and minimally affected by water management were able to maintain lower temperatures by several degrees. Understanding the conditions driving the response of urban streams to climatic extremes can aid

  20. Uncertainty Analysis of Climate Change Impact on Extreme Rainfall Events in the Apalachicola River Basin, Florida

    NASA Astrophysics Data System (ADS)

    Wang, D.; Hagen, S.; Bacopoulos, P.

    2011-12-01

    Climate change impact on the rainfall patterns during the summer season (May -- August) at the Apalachicola River basin (Florida Panhandle coast) is assessed using ensemble regional climate models (RCMs). Rainfall data for both baseline and future years (30-year periods) are obtained from North American Regional Climate Change Assessment Program (NARCCAP) where the A2 emission scenario is used. Trend analysis is conducted based on historical rainfall data from three weather stations. Two methods are used to assess the climate change impact on the rainfall intensity-duration-frequency (IDF) curves, i.e., maximum intensity percentile-based method and sequential bias correction and maximum intensity percentile-based method. As a preliminary result from one RCM, extreme rainfall intensity is found to increase significantly with the increase in rainfall intensity increasing more dramatically with closer proximity to the coast. The projected rainfall pattern changes (spatial and temporal, mean and extreme values) provide guidance for developing adaptation and mitigation strategies on water resources management and ecosystem protections. More rainfall events move from July to June during future years for all three stations; in the upstream, the variability of time occurrence of extreme rainfall increases and more extreme events are shown to occur in June and August instead of May. These temporal shifts of extreme rainfall events will increase the probability of simultaneous heavy rainfall in the downstream and upstream in June during which flooding will be enhanced. The uncertainty analysis on the climate change impact on extreme rainfall events will be presented based on the simulations from the ensemble of RCMs.

  1. 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

  2. Relevance of land forcings and feedbacks in the attribution of climate extremes

    NASA Astrophysics Data System (ADS)

    Seneviratne, S. I.; Davin, E.; Greve, P.; Gudmundsson, L.; Hauser, M.; Hirschi, M.; Mueller, B.; Orlowsky, B.; Orth, R.

    2014-12-01

    Land forcings and feedbacks play an important role in the climate system, in particular for the occurrence of climate extremes. Recent investigations have for instance highlighted the impacts of soil moisture-climate interactions for the development of droughts and heat waves (e.g. Seneviratne et al. 2012, Mueller and Seneviratne 2012, Seneviratne et al. 2013, Orlowsky and Seneviratne 2013). In addition, forcing from land use and land cover changes through modified albedo or turbulent fluxes can also affect the temperature variability in summer (Davin et al. 2014). These effects are important for better understanding the relationships between climate forcing and regional climate changes, and appear relevant for a recent discrepancy between trends in global mean temperature vs hot extremes over land (Seneviratne et al. 2014). This presentation will provide an overview on the underlying processes and on possible approaches for their consideration in attribution research. References:- Davin, E.L., S.I. Seneviratne, P. Ciais, A. Olioso, T. Wang, 2014: Preferential cooling of hot extremes from cropland albedo management. Proc. Natl. Acad. Sci., Published ahead of print June 23, 2014.- Mueller, B., and S.I. Seneviratne, 2012: Hot days induced by precipitation deficits at the global scale. Proceedings of the National Academy of Sciences, 109 (31), 12398-12403, doi: 10.1073/pnas.1204330109.- Orlowsky, B., and S.I. Seneviratne, 2013: Elusive drought: Uncertainty in observed trends and short- and long-term CMIP5 projections. Hydr. Earth Syst. Sci., 17, 1765-1781, doi:10.5194/hess-17-1765-2013- Seneviratne, S.I., N. Nicholls, et al., 2012: Changes in climate extremes and their impacts on the natural physical environment. In: Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation [Field, C.B., et al. (eds.)]. A Special Report of Working Groups I and II of the Intergovernmental Panel on Climate Change, pp. 109-230.- Seneviratne, S.I., et al

  3. Towards a Unified Framework in Hydroclimate Extremes Prediction in Changing Climate

    NASA Astrophysics Data System (ADS)

    Moradkhani, H.; Yan, H.; Zarekarizi, M.; Bracken, C.

    2016-12-01

    Spatio-temporal analysis and prediction of hydroclimate extremes are of paramount importance in disaster mitigation and emergency management. The IPCC special report on managing the risks of extreme events and disasters emphasizes that the global warming would change the frequency, severity, and spatial pattern of extremes. In addition to climate change, land use and land cover changes also influence the extreme characteristics at regional scale. Therefore, natural variability and anthropogenic changes to the hydroclimate system result in nonstationarity in hydroclimate variables. In this presentation recent advancements in developing and using Bayesian approaches to account for non-stationarity in hydroclimate extremes are discussed. Also, implications of these approaches in flood frequency analysis, treatment of spatial dependence, the impact of large-scale climate variability, the selection of cause-effect covariates, with quantification of model errors in extreme prediction is explained. Within this framework, the applicability and usefulness of the ensemble data assimilation for extreme flood predictions is also introduced. Finally, a practical and easy to use approach for better communication with decision-makers and emergency managers is presented.

  4. Impacts of a changing climate on a century of extreme flood regime of northwest Australia

    NASA Astrophysics Data System (ADS)

    Rouillard, A.; Skrzypek, G.; Dogramaci, S.; Turney, C.; Grierson, P. F.

    2014-10-01

    Globally, there has been much recent effort to improve understanding of climate change-related shifts in rainfall patterns, variability and extremes. Comparatively little work have focused on how such shifts might be altering hydrological regimes within arid regional basins, where impacts are expected to be most significant. Here, we sought to identify the main hydroclimatic determinants of the strongly episodic flood regime of a large catchment in the semi-arid, subtropical northwest of Australia and to establish the background of hydrologic variability for the region over the last century. We used a monthly sequence of satellite images to quantify surface water expression on the Fortescue Marsh, the largest water feature of inland northwest Australia, from 1988 to 2012. We used this sequence together with instrumental rainfall data to build a multiple linear model and reconstruct monthly history of floods and droughts since 1912. We found that severe and intense regional rainfall events, as well as the sequence of recharge events both within and between years, determine surface water expression on the floodplain (i.e., total rainfall, number of rain days and carried-over inundated area; R2adj = 0.79; p value < 0.001, ERMSP = 56 km2). The most severe inundation (~1000 km2) over the last century was recorded in 2000. The Fortescue Marsh was completely dry for 32% of all years, for periods of up to four consecutive years. Extremely wet years (seven of the 100 years) caused the Marsh to remain inundated for up to 12 months; only 25% of years (9% of all months) had floods of greater than 300 km2. Duration, severity and frequency of inundations between 1999 and 2006 were above average and unprecedented when compared to the last century. While there is high inter-annual variability in the system, changes to the flooding regime over the last 20 years suggest that the wetland will become more persistent in response to increased frequency and intensity of extreme rainfall

  5. Mapping Extreme Heat Vulnerability and Health Outcomes to inform the District of Columbia's Climate Adaptation Plan

    NASA Astrophysics Data System (ADS)

    Declet-Barreto, J.; Wilhelmi, O.; Goggans, A.

    2016-12-01

    In this collaborative engagement, scientists are partnering with the District of Columbia (DC) to develop an extreme heat vulnerability assessment. To do so, we map socio-demographic and built environment indicators of extreme heat vulnerability in Census Tracts in DC neighborhoods. In order to provide information useful for DC public health and urban planning practitioners, we aggregate the indicators into an index of extreme heat vulnerability. We compare the index against heat-related call data from DC's 911 system to better understand the socio-spatial distribution of extreme heat-related health outcomes. Our assessment can help inform the District's Climate Adaptation Plan as well as increase public engagement in reducing vulnerability to extreme heat.

  6. 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

  7. Extremes of temperature, oxygen and blooms in the Baltic sea in a changing climate.

    PubMed

    Neumann, Thomas; Eilola, Kari; Gustafsson, Bo; Müller-Karulis, Bärbel; Kuznetsov, Ivan; Meier, H E Markus; Savchuk, Oleg P

    2012-09-01

    In the future, the Baltic Sea ecosystem will be impacted both by climate change and by riverine and atmospheric nutrient inputs. Multi-model ensemble simulations comprising one IPCC scenario (A1B), two global climate models, two regional climate models, and three Baltic Sea ecosystem models were performed to elucidate the combined effect of climate change and changes in nutrient inputs. This study focuses on the occurrence of extreme events in the projected future climate. Results suggest that the number of days favoring cyanobacteria blooms could increase, anoxic events may become more frequent and last longer, and salinity may tend to decrease. Nutrient load reductions following the Baltic Sea Action Plan can reduce the deterioration of oxygen conditions.

  8. 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

  9. Decreasing spatial dependence in extreme snowfall in the French Alps since 1958 under climate change

    NASA Astrophysics Data System (ADS)

    Nicolet, G.; Eckert, N.; Morin, S.; Blanchet, J.

    2016-07-01

    Whereas changes in magnitude of geophysical extremes under climate change have received significant attention, potential concomitant changes in spatial dependence structures have remained unexplored so far. Here we provide first evidence of such an effect, highlighting a significant trend in the spatial dependence structure of snowfall extremes in the French Alps at decadal time scale. Specifically, we process a comprehensive data set of winter maximum snowfall from all over the French Alps collected in 90 stations from 1958 to 2012. We estimate extremal dependence over 20 year moving estimation windows taking into account possible anisotropy potentially related to orographic effects and/or patterns in atmospheric flows. For each window, we derive a range representing the distance above which extremes are almost independent. We show that snowfall extremes tended to become less spatially dependent over time, with the dependence range reduced roughly by half during the study period. We demonstrate the connection between this trend and local and synoptic climatic variables associated with the current climate change context. In details, the decreasing pattern in extremal dependence is concomitant with a trend toward less harsh winter conditions. It is attributable at first to the increase in temperature and its major control on the snow/rain partitioning. Yet a magnitude effect, with less dependent extremes due to a decrease in intensity of precipitation, also exists. Finally, we show that our results are largely insensitive to the minimal modeling assumptions necessary to our data-based approach. This robustness makes it potentially suitable for various other studies in the field of geophysical extremes.

  10. 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.

  11. 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 ...

  12. 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 ...

  13. Damage Characteristics of Altered and Unaltered Diabases Subjected to Extremely Cold Freeze-Thaw Cycles

    NASA Astrophysics Data System (ADS)

    Luo, Xuedong; Jiang, Nan; Zuo, Changqun; Dai, Zhenwei; Yan, Suntao

    2014-11-01

    Altered and unaltered diabases are commonly deposited on hydrothermally mineralized slopes. To study their damage characteristics during freeze-thaw cycles, they were sampled from Cihai iron ore mine located in an extremely cold region, Xinjiang, China and examined using acoustic and X-ray diffraction experiments to analyze the differences in their main mineral components and explore their damage characteristics under freeze-thaw conditions. Based on the results of these experiments, their damage and degradation patterns were obtained and the evolution of their physical characteristics including the rock mass loss rate ( L F), rock strength loss rate ( R σ ), P-wave velocity loss rate ( V l), and freeze-thaw coefficient ( K f) was analyzed. In addition, two groups of equations were established to characterize the relationships of these physical and mechanical properties of the rock specimens with the number and temperature of freeze-thaw cycles. The results show that the mineral composition of diabase changes during its alteration, showing increased clay and calcite, and the degradation and evolution patterns of the physical and mechanical parameters ( L F, R σ , V l, and K f) of the altered rocks during freeze-thaw cycles are different from those of diabase, with the altered diabase exhibiting greater damage than the diabase.

  14. Uncertainty in projected point precipitation extremes for hydrological impact analysis of climate change

    NASA Astrophysics Data System (ADS)

    Van Uytven, Els; Willems, Patrick

    2017-04-01

    Current trends in the hydro-meteorological variables indicate the potential impact of climate change on hydrological extremes. Therefore, they trigger an increased importance climate adaptation strategies in water management. The impact of climate change on hydro-meteorological and hydrological extremes is, however, highly uncertain. This is due to uncertainties introduced by the climate models, the internal variability inherent to the climate system, the greenhouse gas scenarios and the statistical downscaling methods. In view of the need to define sustainable climate adaptation strategies, there is a need to assess these uncertainties. This is commonly done by means of ensemble approaches. Because more and more climate models and statistical downscaling methods become available, there is a need to facilitate the climate impact and uncertainty analysis. A Climate Perturbation Tool has been developed for that purpose, which combines a set of statistical downscaling methods including weather typing, weather generator, transfer function and advanced perturbation based approaches. By use of an interactive interface, climate impact modelers can apply these statistical downscaling methods in a semi-automatic way to an ensemble of climate model runs. The tool is applicable to any region, but has been demonstrated so far to cases in Belgium, Suriname, Vietnam and Bangladesh. Time series representing future local-scale precipitation, temperature and potential evapotranspiration (PET) conditions were obtained, starting from time series of historical observations. Uncertainties on the future meteorological conditions are represented in two different ways: through an ensemble of time series, and a reduced set of synthetic scenarios. The both aim to span the full uncertainty range as assessed from the ensemble of climate model runs and downscaling methods. For Belgium, for instance, use was made of 100-year time series of 10-minutes precipitation observations and daily

  15. Hydrological Alterations Due to Climate-Induced Regional Vegetation Change

    NASA Astrophysics Data System (ADS)

    White, A. B.; Vivoni, E. R.; Springer, E. P.

    2010-12-01

    An extended, severe drought in the southwestern U.S. from 2000 to 2003 was accompanied by increased temperatures and bark beetle infestations, inducing the large-scale mortality of woody overstory (Pinus edulis). The consequential redistribution of water, radiation, and nutrient availability modified the ecosystem phenology, species composition, and forced the ecosystem to transition into a new state. We hypothesize that the hydrological processes in the ecosystem were also altered due to the mortality. Thus, our objective is to investigate changes in the soil-vegetation-atmosphere continuum at the watershed scale. The Rio Ojo Caliente Basin is a subbasin of the Upper Rio Grande, located mostly in New Mexico, and is approximately 1,000 km2. Examining a remotely-sensed vegetation index (1-km AVHRR NDVI from 1990 to 2006), there is an increasing trend in the NDVI from 1989 to 1999 (pre-mortality period), a decreasing trend from 2000 to 2003 (mortality period), and a dramatic increasing trend from 2004 to 2006 (post-mortality period) in which the NDVI rebounds to nearly pre-mortality magnitudes. This pattern exists across varying spatial scales (plot to watershed to region) and signifies a profound alteration in the ecosystem, for while the vegetation composition was altered to a great degree, the system rapidly returned to a homeostatic state balancing resource supply and use during the post-mortality period. To investigate hydrological changes due to the mortality, we employ a physically-based, distributed hydrologic model, tRIBS (TIN-based Real-Time Integrated Basin Simulator) for the Rio Ojo Caliente Basin. STATSGO 1-km soils data, 10-meter National Elevation Dataset DEMs, Carson National Forest vegetation species data, and MM5-downscaled NCEP/NCAR Reanalysis-I meteorologic data are used as model inputs. A combination of MODIS and AVHRR remote-sensing data, values from the literature, and field data from a long-term, pi {n}on-juniper (PJ) observation site in Los

  16. 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

  17. 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

  18. Precipitation extreme changes exceeding moisture content increases in MIROC and IPCC climate models.

    PubMed

    Sugiyama, Masahiro; Shiogama, Hideo; Emori, Seita

    2010-01-12

    Precipitation extreme changes are often assumed to scale with, or are constrained by, the change in atmospheric moisture content. Studies have generally confirmed the scaling based on moisture content for the midlatitudes but identified deviations for the tropics. In fact half of the twelve selected Intergovernmental Panel on Climate Change (IPCC) models exhibit increases faster than the climatological-mean precipitable water change for high percentiles of tropical daily precipitation, albeit with significant intermodel scatter. Decomposition of the precipitation extreme changes reveals that the variations among models can be attributed primarily to the differences in the upward velocity. Both the amplitude and vertical profile of vertical motion are found to affect precipitation extremes. A recently proposed scaling that incorporates these dynamical effects can capture the basic features of precipitation changes in both the tropics and midlatitudes. In particular, the increases in tropical precipitation extremes significantly exceed the precipitable water change in Model for Interdisciplinary Research on Climate (MIROC), a coupled general circulation model with the highest resolution among IPCC climate models whose precipitation characteristics have been shown to reasonably match those of observations. The expected intensification of tropical disturbances points to the possibility of precipitation extreme increases beyond the moisture content increase as is found in MIROC and some of IPCC models.

  19. 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

    2013-06-27

    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.

  20. 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.

  1. 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

  2. Precipitation extreme changes exceeding moisture content increases in MIROC and IPCC climate models

    PubMed Central

    Sugiyama, Masahiro; Shiogama, Hideo; Emori, Seita

    2010-01-01

    Precipitation extreme changes are often assumed to scale with, or are constrained by, the change in atmospheric moisture content. Studies have generally confirmed the scaling based on moisture content for the midlatitudes but identified deviations for the tropics. In fact half of the twelve selected Intergovernmental Panel on Climate Change (IPCC) models exhibit increases faster than the climatological-mean precipitable water change for high percentiles of tropical daily precipitation, albeit with significant intermodel scatter. Decomposition of the precipitation extreme changes reveals that the variations among models can be attributed primarily to the differences in the upward velocity. Both the amplitude and vertical profile of vertical motion are found to affect precipitation extremes. A recently proposed scaling that incorporates these dynamical effects can capture the basic features of precipitation changes in both the tropics and midlatitudes. In particular, the increases in tropical precipitation extremes significantly exceed the precipitable water change in Model for Interdisciplinary Research on Climate (MIROC), a coupled general circulation model with the highest resolution among IPCC climate models whose precipitation characteristics have been shown to reasonably match those of observations. The expected intensification of tropical disturbances points to the possibility of precipitation extreme increases beyond the moisture content increase as is found in MIROC and some of IPCC models. PMID:20080720

  3. 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

  4. 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

  5. Land use alterations, hydrology and climate alterations analysis approach for water supply guarantee

    NASA Astrophysics Data System (ADS)

    Pereira, V.; Walter, M. T.; Teixeira Filho, J.

    2010-12-01

    The present paper investigates the hydrological land use conversion effects in a watershed that supplies 10 million people in the São Paulo Metropolitan Region of Brazil. The main point of this investigation is to identify, at the regional-scale, how much of the land use conversion from native forest to eucalyptus using a non-ideal tillage system is necessary to change the hydrological conditions. In addition to short and, often incomplete data records, determining cause-and-effect relationships was further complicated by concurrent and systematic changes in precipitation, land use, and discharge. Both minimum low flows following prolonged periods without precipitation and recession-flow analysis showed significant negative trends. During the same period, deforestation increased by 2.4 km2/year and eucalyptus-silviculture activity increased by 2.6 km2/year. The dry and wet seasons and annual discharge decreased significantly (p-value<0.01). The precipitation also decreased significantly (p-value<0.01). However, the evapotranspiration losses, estimated as the difference between annual precipitation and discharge, increased significantly (p-value<0.02). The results showed that the negative trends in all discharge analysis are partially related to decreasing precipitation. The increase evapotranspiration losses, given decreasing precipitation, are most likely related to the increases in silviculture and likely also contributed to decreases in discharge. The results indicate that both climate and land use alterations could have a huge impact in water supply in watersheds.

  6. [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.

  7. Modeling Studies of Climate Impacts and Extreme Events in California Mountain Ecosystems

    NASA Astrophysics Data System (ADS)

    Shupe, J.; Potter, C.; Kramer, M.; Genovese, V.; Gross, P.

    2005-12-01

    This study describes research using the CASA (Carnegie-Ames-Stanford) ecosystem model with HYDRA surface hydrologic model for the state of California to understand the effects of potential land cover and climate events on mountain ecosystems and regional water resources. The models are run at 1-km resolution to capture localized topographic effects at the regional scale. To assess HYDRA's ability to estimate actual water flows in both extreme and non-extreme years, we have compared HYDRA's results with gauge station data throughout the state. Historical predictions for the Northern Coastal Range show that HYDRA's estimate of actual water flow improves as the model progresses downstream within a watershed. Other complex watersheds that display similar characteristics include the Klamath and the San Joaquin Valley. High resolution studies of land cover and surface hydrology are presented for the Central Coast Range of California, which is impacted by extreme events of fire and rapidly changing climate gradients.

  8. Climatic changes of extreme precipitation in Denmark from 1874 to 2100

    NASA Astrophysics Data System (ADS)

    Arnbjerg-Nielsen, Karsten; Bülow Gregersen, Ida; Sunyer, Maria; Madsen, Henrik; Rosbjerg, Dan

    2014-05-01

    During the past 30 years rather dramatic changes in extreme precipitation have been observed in Denmark. These changes are mainly in the frequency of extreme events, but there is also a tendency towards more severe events. Both are considered effects of anthropogenic climate change. The increase in precipitation extremes has led to inundations in most of the larger cities during the last 10 years. The flood in Copenhagen in 2011 implied the second highest damage costs measured in Denmark during the last 100 years. To establish cities that are resilient to pluvial floods robust projections of the frequency and intensity of extreme precipitation events in a changing climate are needed. Additionally, it is equally important to understand the natural variation on which the anthropogenic changes are imposed. This study presents the results of a coordinated effort to estimate the changes and uncertainties in Danish design rainfall. Trends and oscillations are identified in five daily precipitation records from 1874 to present, 83 records from high-resolution rain-gauges from 1979 to present and 18 state-of-the-art climate model simulations. It is shown that the frequency of extreme events in the past has oscillated with a cycle of 25-35 years, a behavior that can in part be explained by sea level pressure differences over the Atlantic. Projections based on the historical observations suggest that precipitation extremes in the Eastern part of Denmark should have been ascending in the last two decades. However, the increase has continued longer than expected and with larger amplitude in the most recent years. This indicates a likely influence from anthropogenic greenhouse gas emissions. With the complex combination of general increase and natural variation several additional years of observation are needed before this hypothesis can be evaluated by statistical means. Extensive analysis of 18 different regional climate model (RCM) simulations shows that anthropogenic

  9. 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

  10. Scaling precipitation extremes with temperature in the Mediterranean: past climate assessment and projection in anthropogenic scenarios

    NASA Astrophysics Data System (ADS)

    Drobinski, Philippe; Silva, Nicolas Da; Panthou, Gérémy; Bastin, Sophie; Muller, Caroline; Ahrens, Bodo; Borga, Marco; Conte, Dario; Fosser, Giorgia; Giorgi, Filippo; Güttler, Ivan; Kotroni, Vassiliki; Li, Laurent; Morin, Efrat; Önol, Bariş; Quintana-Segui, Pere; Romera, Raquel; Torma, Csaba Zsolt

    2016-03-01

    In this study we investigate the scaling of precipitation extremes with temperature in the Mediterranean region by assessing against observations the present day and future regional climate simulations performed in the frame of the HyMeX and MED-CORDEX programs. Over the 1979-2008 period, despite differences in quantitative precipitation simulation across the various models, the change in precipitation extremes with respect to temperature is robust and consistent. The spatial variability of the temperature-precipitation extremes relationship displays a hook shape across the Mediterranean, with negative slope at high temperatures and a slope following Clausius-Clapeyron (CC)-scaling at low temperatures. The temperature at which the slope of the temperature-precipitation extreme relation sharply changes (or temperature break), ranges from about 20 °C in the western Mediterranean to <10 °C in Greece. In addition, this slope is always negative in the arid regions of the Mediterranean. The scaling of the simulated precipitation extremes is insensitive to ocean-atmosphere coupling, while it depends very weakly on the resolution at high temperatures for short precipitation accumulation times. In future climate scenario simulations covering the 2070-2100 period, the temperature break shifts to higher temperatures by a value which is on average the mean regional temperature change due to global warming. The slope of the simulated future temperature-precipitation extremes relationship is close to CC-scaling at temperatures below the temperature break, while at high temperatures, the negative slope is close, but somewhat flatter or steeper, than in the current climate depending on the model. Overall, models predict more intense precipitation extremes in the future. Adjusting the temperature-precipitation extremes relationship in the present climate using the CC law and the temperature shift in the future allows the recovery of the temperature-precipitation extremes

  11. 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

  12. Predicting Ice Sheet and Climate Evolution at Extreme Scales

    SciTech Connect

    Heimbach, Patrick

    2016-02-06

    A main research objectives of PISCEES is the development of formal methods for quantifying uncertainties in ice sheet modeling. Uncertainties in simulating and projecting mass loss from the polar ice sheets arise primarily from initial conditions, surface and basal boundary conditions, and model parameters. In general terms, two main chains of uncertainty propagation may be identified: 1. inverse propagation of observation and/or prior onto posterior control variable uncertainties; 2. forward propagation of prior or posterior control variable uncertainties onto those of target output quantities of interest (e.g., climate indices or ice sheet mass loss). A related goal is the development of computationally efficient methods for producing initial conditions for an ice sheet that are close to available present-day observations and essentially free of artificial model drift, which is required in order to be useful for model projections (“initialization problem”). To be of maximum value, such optimal initial states should be accompanied by “useful” uncertainty estimates that account for the different sources of uncerainties, as well as the degree to which the optimum state is constrained by available observations. The PISCEES proposal outlined two approaches for quantifying uncertainties. The first targets the full exploration of the uncertainty in model projections with sampling-based methods and a workflow managed by DAKOTA (the main delivery vehicle for software developed under QUEST). This is feasible for low-dimensional problems, e.g., those with a handful of global parameters to be inferred. This approach can benefit from derivative/adjoint information, but it is not necessary, which is why it often referred to as “non-intrusive”. The second approach makes heavy use of derivative information from model adjoints to address quantifying uncertainty in high-dimensions (e.g., basal boundary conditions in ice sheet models). The use of local gradient, or

  13. Global crop yield response to extreme heat stress under multiple climate change futures

    NASA Astrophysics Data System (ADS)

    Deryng, Delphine; Conway, Declan; Ramankutty, Navin; Price, Jeff; Warren, Rachel

    2014-03-01

    Extreme heat stress during the crop reproductive period can be critical for crop productivity. Projected changes in the frequency and severity of extreme climatic events are expected to negatively impact crop yields and global food production. This study applies the global crop model PEGASUS to quantify, for the first time at the global scale, impacts of extreme heat stress on maize, spring wheat and soybean yields resulting from 72 climate change scenarios for the 21st century. Our results project maize to face progressively worse impacts under a range of RCPs but spring wheat and soybean to improve globally through to the 2080s due to CO2 fertilization effects, even though parts of the tropic and sub-tropic regions could face substantial yield declines. We find extreme heat stress at anthesis (HSA) by the 2080s (relative to the 1980s) under RCP 8.5, taking into account CO2 fertilization effects, could double global losses of maize yield (ΔY = -12.8 ± 6.7% versus - 7.0 ± 5.3% without HSA), reduce projected gains in spring wheat yield by half (ΔY = 34.3 ± 13.5% versus 72.0 ± 10.9% without HSA) and in soybean yield by a quarter (ΔY = 15.3 ± 26.5% versus 20.4 ± 22.1% without HSA). The range reflects uncertainty due to differences between climate model scenarios; soybean exhibits both positive and negative impacts, maize is generally negative and spring wheat generally positive. Furthermore, when assuming CO2 fertilization effects to be negligible, we observe drastic climate mitigation policy as in RCP 2.6 could avoid more than 80% of the global average yield losses otherwise expected by the 2080s under RCP 8.5. We show large disparities in climate impacts across regions and find extreme heat stress adversely affects major producing regions and lower income countries.

  14. Global crop yield response to extreme heat stress under multiple climate change futures

    NASA Astrophysics Data System (ADS)

    Deryng, D.; Conway, D.; Ramankutty, N.; Price, J.; Warren, R.

    2014-12-01

    Extreme heat stress during the crop reproductive period can be critical for crop productivity. Projected changes in the frequency and severity of extreme climatic events are expected to negatively impact crop yields and global food production. This study applies the global crop model PEGASUS to quantify, for the first time at the global scale, impacts of extreme heat stress on maize, spring wheat and soybean yields resulting from 72 climate change scenarios for the 21st century. Our results project maize to face progressively worse impacts under a range of RCPs but spring wheat and soybean to improve globally through to the 2080s due to CO2 fertilization effects, even though parts of the tropic and sub-tropic regions could face substantial yield declines. We find extreme heat stress at anthesis (HSA) by the 2080s (relative to the 1980s) under RCP 8.5, taking into account CO2 fertilization effects, could double global losses of maize yield (dY = -12.8 ± 6.7% versus -7.0 ± 5.3% without HSA), reduce projected gains in spring wheat yield by half (dY = 34.3 ± 13.5% versus 72.0 ± 10.9% without HSA) and in soybean yield by a quarter (dY = 15.3 ± 26.5% versus 20.4 ± 22.1% without HSA). The range reflects uncertainty due to differences between climate model scenarios; soybean exhibits both positive and negative impacts, maize is generally negative and spring wheat generally positive. Furthermore, when assuming CO2 fertilization effects to be negligible, we observe drastic climate mitigation policy as in RCP 2.6 could avoid more than 80% of the global average yield losses otherwise expected by the 2080s under RCP 8.5. We show large disparities in climate impacts across regions and find extreme heat stress adversely affects major producing regions and lower income countries.

  15. 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.

  16. Wavelet analysis of precipitation extremes over Canadian ecoregions and teleconnections to large-scale climate anomalies

    NASA Astrophysics Data System (ADS)

    Tan, Xuezhi; Gan, Thian Yew; Shao, Dongguo

    2016-12-01

    To detect significant interannual and interdecadal oscillations and their teleconnections to large-scale climate anomalies such as El Niño-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and North Atlantic Oscillation (NAO), monthly and seasonal maximum daily precipitation (MMDP and SMDP) from 131 stations across Canada were analyzed by using variants of wavelet analysis. Interannual (1-8 years) oscillations were found to be more significant than interdecadal (8-30 years) oscillations for all selected stations, and the oscillations are both spatial and time-dependent. Similarly, the significant wavelet coherence and the phase difference between leading principal components of monthly precipitation extremes and climate indices were highly variable in time and in periodicity, and a single climate index explains less than 40% of the total variability. Partial wavelet coherence analysis shows that both ENSO and PDO modulated the interannual variability and PDO modulated the interdecadal variability, of MMDP over Canada. NAO is correlated with the western MMDP at interdecadal scale and the eastern MMDP at interannual scale. The composite analysis shows that precipitation extremes at about three fourths of the stations have been significantly influenced by ENSO and PDO patterns, while about one half of the stations by the NAO patterns. The magnitude of SMDP in extreme El Niño years, and extreme PDO event of positive phase, was mostly lower (higher) over the Canadian Prairies in summer and winter (spring and autumn) than in extreme La Niña years. Overall, the degree of influence of large-scale climate patterns on Canadian precipitation extremes varies by season and by region.

  17. Physics of Extreme Climate Events: Illustration Via Attribution of Two Recent Cases

    NASA Astrophysics Data System (ADS)

    Hoerling, M. P.; Dole, R. M.; Perlwitz, J.; Pegion, K.

    2011-12-01

    Two recent occurrences of extreme climate events are used to explore current scientific understanding of their causes and their predictability; the July 2010 Russian heat wave, and the April 2011 Ohio Valley heavy rains. The analysis combines statistical with physically-based assessments of each in order to provide an overview of the tools and methods that are commonly used in attribution studies. Assessments of extreme events are motivated by basic scientific interest, public interest, decision maker requirements, and policy concerns. First among the climate information required in conducting a rigorous science assessment is an accurate description of what happened. This often involves framing an event within a statistical context that spans historical records. For instance, is a particular heat wave a 1 in 100 year event, and what are its historical analogs? Second is the need to explain why an event happened. This is the basic motivation for attribution science; the process of establishing physical causes for observed climate conditions including an appraisal of plausible mechanisms responsible for such conditions. Of increasing interest is to determine whether factors causing extreme events in the 21st Century are different from those that occurred in the 20th Century. Third among climate information needs is to determine the likelihood of such events happening again. This may involve a statistical appraisal of whether the future occurrences of low-probability extreme events will change due to anthropogenic greenhouse gas forcing. It may also involve a statement of predictability; evaluating the basis for anticipating a particular extreme event. Each of these three issues are addressed using the case study frameworks of the extreme 2010 summer Russian heat wave and the 2011 spring Ohio Valley flooding rains.

  18. Estimating the impact of extreme climatic events on riverine sediment transport: new tools and methods

    NASA Astrophysics Data System (ADS)

    Lajeunesse, E.; Delacourt, C.; Allemand, P.; Limare, A.; Dessert, C.; Ammann, J.; Grandjean, P.

    2010-12-01

    A series of recent works have underlined that the flux of material exported outside of a watershed is dramatically increased during extreme climatic events, such as storms, tropical cyclones and hurricanes [Dadson et al., 2003 and 2004; Hilton et al., 2008]. Indeed the exceptionally high rainfall rates reached during these events trigger runoff and landsliding which destabilize slopes and accumulate a significant amount of sediments in flooded rivers. This observation raises the question of the control that extreme climatic events might exert on the denudation rate and the morphology of watersheds. Addressing this questions requires to measure sediment transport in flooded rivers. However most conventional sediment monitoring technics rely on manned operated measurements which cannot be performed during extreme climatic events. Monitoring riverine sediment transport during extreme climatic events remains therefore a challenging issue because of the lack of instruments and methodologies adapted to such extreme conditions. In this paper, we present a new methodology aimed at estimating the impact of extreme events on sediment transport in rivers. Our approach relies on the development of two instruments. The first one is an in-situ optical instrument, based on a LISST-25X sensor, capable of measuring both the water level and the concentration of suspended matter in rivers with a time step going from one measurement every hour at low flow to one measurement every 2 minutes during a flood. The second instrument is a remote controlled drone helicopter used to acquire high resolution stereophotogrammetric images of river beds used to compute DEMs and to estimate how flash floods impact the granulometry and the morphology of the river. These two instruments were developed and tested during a 1.5 years field survey performed from june 2007 to january 2009 on the Capesterre river located on Basse-Terre island (Guadeloupe archipelago, Lesser Antilles Arc).

  19. 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

  20. 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

  1. Amplification of extreme precipitation response to climate change over Lake Victoria

    NASA Astrophysics Data System (ADS)

    Thiery, Wim; Davin, Edouard; Seneviratne, Sonia; Bedka, Kristopher; van Lipzig, Nicole

    2015-04-01

    Casualties among fishermen operating on Lake Victoria are estimated to amount up to several thousand per year, leading to the dubious distinction of "world's most lethal lake". Most of the casualties are caused by severe thunderstorms occurring at night, when surface winds converge over the lake and trigger deep convection of air masses moistened by the lake. With the climate change induced raise in troposphere temperatures, the frequency and intensity of these extremes are likely to increase. However, up to now only very little is known about the processes underlying this nighttime convection, and how it will be affected by climate change. We examine the impact of climate change on hazardous thunderstorms over Lake Victoria by conducting a set of regional climate model simulations which resolve individual lakes and explicitly compute lake temperatures. The regional climate model COSMO-CLM² is used to dynamically downscale a CORDEX-Africa projection (COSMO-CLM/MPI-ESM-LR) under RCP8.5 to 7 km grid spacing for the periods 1981-2010 and 2071-2100. Based on these high resolution simulations, we project that the increase in extreme precipitation is amplified over Lake Victoria compared to surrounding land area, consistent with projections from the (courser-scale) CORDEX-Africa ensemble. Moreover, the strongest extremes are found to follow the Clausius-Clapeyron scaling over the lake surface only. Finally, we investigate controls on the occurrence of this extreme precipitation in the present-day climate using satellite observations and a dynamical reanalysis downscaling, and detect a strong relationship with antecedent daytime land thunderstorms. Besides supplying moisture, these storms also modify mesoscale circulation in favor of strong over-lake convection the following night. Extending this analysis will make it possible to attribute the projected lake amplification effect to changes in the controlling factors.

  2. 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

  3. The influence of altered lower-extremity kinematics on patellofemoral joint dysfunction: a theoretical perspective.

    PubMed

    Powers, Christopher M

    2003-11-01

    Although patellofemoral pain (PFP) is recognized as being one of the most common disorders of the lower extremity, treatment guidelines and underlying rationales remain vague and controversial. The premise behind most treatment approaches is that PFP is the result of abnormal patellar tracking and/or patellar malalignment. Given as such, interventions typically focus on the joint itself and have traditionally included strengthening the vastus medialis oblique, taping, bracing, soft tissue mobilization, and patellar mobilization. More recently, it has been recognized that the patellofemoral joint and, therefore, PFP may be influenced by the interaction of the segments and joints of the lower extremity. In particular, abnormal motion of the tibia and femur in the transverse and frontal planes may have an effect on patellofemoral joint mechanics. With this in mind, interventions aimed at controlling hip and pelvic motion (proximal stability) and ankle/foot motion (distal stability) may be warranted and should be considered when treating persons with patellofemoral joint dysfunction. The purpose of this paper is to provide a biomechanical overview of how altered lower-extremity mechanics may influence the patellofemoral joint. By addressing these factors, better long-term treatment success and prevention may be achieved.

  4. 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)

  5. 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.

  6. Changes in winter precipitation extremes for the western United States under a warmer climate as simulated by regional climate models

    SciTech Connect

    Dominguez, F; Rivera, E; Lettenmaier, D P; Castro1, and C. L.

    2012-03-01

    We find a consistent and statistically significant increase in the intensity of future extreme winter precipitation events over the western United States, as simulated by an ensemble of regional climatemodels (RCMs) driven by IPCC AR4 global climate models (GCMs). All eight simulations analyzed in this work consistently show an increase in the intensity of extreme winter precipitation with the multi-model mean projecting an area-averaged 12.6% increase in 20-year return period and 14.4% increase in 50-year return period daily precipitation. In contrast with extreme precipitation, the multi-model ensemble shows a decrease in mean winter precipitation of approximately 7.5% in the southwestern US, while the interior west shows less statistically robust increases.

  7. Analysis of extreme climatic features over South America from CLARIS-LPB ensemble of regional climate models for future conditions

    NASA Astrophysics Data System (ADS)

    Sanchez, E.; Zaninelli, P.; Carril, A.; Menendez, C.; Dominguez, M.

    2012-04-01

    An ensemble of seven regional climate models (RCM) included in the European CLARIS-LPB project (A Europe-South America Network for Climate Change Assessment and Impact Studies in La Plata Basin) are used to study how some features related to climatic extremes are projected to be changed by the end of XXIst century. These RCMs are forced by different IPCC-AR4 global climate models (IPSL, ECHAM5 and HadCM3), covering three different 30-year periods: present (1960-1990), near future (2010-2040) and distant future (2070-2100), with 50km of horizontal resolution. These regional climate models have previously been forced with ERA-Interim reanalysis, in a consistent procedure with CORDEX (A COordinated Regional climate Downscaling EXperiment) initiative for the South-America domain. The analysis shows a good agreement among them and the available observational databases to describe the main features of the mean climate of the continent. Here we focus our analysis on some topics of interest related to extreme events, such as the development of diagnostics related to dry-spells length, the structure of the frequency distribution functions over several subregions defined by more or less homogeneous climatic conditions (four sub-basins over the La Plata Basin, the southern part of the Amazon basin, Northeast Brazil, and the South Atlantic Convergence Zone (SACZ)), the structure of the annual cycle and their main features and relation with the length of the seasons, or the frequency of anomalous hot or cold events. One shortcoming that must be considered is the lack of observational databases with both time and spatial frequency to validate model outputs. At the same time, one challenging issue of this study is the regional modelling description of a continent where a huge variety of climates are present, from desert to mountain conditions, and from tropical to subtropical regimes. Another basic objective of this preliminary work is also to obtain a measure of the spread among

  8. 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.

  9. Combining regional climate and national human development scenarios to estimate future vulnerability to extreme climate and weather events

    NASA Astrophysics Data System (ADS)

    Patt, A.; Nussbaumer, P.

    2009-04-01

    Extreme climate and weather events such as droughts, floods, and tropical cyclones account for over 60% of the loss of life, and over 90% of total impacts, from natural disasters. Both observed trends and global climate models (GCMs) suggest that the frequency and intensity of extreme events is increasing, and will continue to increase as a result of climate change. Among planners and policy-makers at both national and international levels there is thus concern that this rise in extreme events will lead to greater losses in the future. Since low levels of development are associated with greater numbers of people killed and needing emergency assistance from natural disasters, the concern is most pronounced for least developed countries. If, however, these countries make substantial improvements in their levels of human development, as leading forecasters suggest may be the case over the coming decades, then their vulnerability to extreme events may fall. In this study, we examine the potential combined effects of increased extreme event frequency and improved levels of human development, to generate scenarios of risk levels into the second half of the century. It is the African continent for which these results may be the most relevant, since it is widely viewed as most vulnerable to increased risks from climate change; we focus on the particular country of Mozambique, which has experienced high losses from droughts, floods, and tropical cyclones in recent decades, and stands out as being among the most vulnerable in Africa. To assess the change in risk levels from the present until 2060, we pull together three pieces of analysis. The first is a statistical analysis of the losses from 1990-2007 from climate-related disasters, using national level data from the Centre for Research on the Epidemiology of Disasters (CRED) and the United Nations. From this analysis, we establish statistical relationships between several drivers of vulnerability—including country size

  10. Local atmospheric decoupling in complex topography alters climate change impacts

    Treesearch

    Christopher Daly; David R. Conklin; Michael H. Unsworth

    2009-01-01

    Cold air drainage and pooling occur in many mountain valleys, especially at night and during winter. Local climate regimes associated with frequent cold air pooling have substantial impacts on species phenology, distribution, and diversity. However, little is known about how the degree and frequency of cold air drainage and pooling will respond to a changing climate....

  11. Extreme waves from tropical cyclones and climate change in the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Appendini, Christian M.; Pedrozo-Acuña, Adrian; Meza-Padilla, Rafael; Torres-Freyermuth, Alec; Cerezo-Mota, Ruth; López-González, José

    2017-04-01

    Tropical cyclones generate extreme waves that represent a risk to infrastructure and maritime activities. The projection of the tropical cyclones derived wave climate are challenged by the short historical record of tropical cyclones, their low occurrence, and the poor wind field resolution in General Circulation Models. In this study we use synthetic tropical cyclones to overcome such limitations and be able to characterize present and future wave climate associated with tropical cyclones in the Gulf of Mexico. Synthetic events derived from the NCEP/NCAR atmospheric reanalysis and the Coupled Model Intercomparison Project Phase 5 models NOAA/GFDL CM3 and UK Met Office HADGEM2-ES, were used to force a third generation wave model to characterize the present and future wave climate under RCP 4.5 and 8.5 escenarios. An increase in wave activity is projected for the future climate, particularly for the GFDL model that shows less bias in the present climate, although some areas are expected to decrease the wave energy. The practical implications of determining the future wave climate is exemplified by means of the 100-year design wave, where the use of the present climate may result in under/over design of structures, since the lifespan of a structure includes the future wave climate period.

  12. Impact of climate change on extreme rainfall events and flood risk in India

    NASA Astrophysics Data System (ADS)

    Guhathakurta, P.; Sreejith, O. P.; Menon, P. A.

    2011-06-01

    The occurrence of exceptionally heavy rainfall events and associated flash floods in many areas during recent years motivate us to study long-term changes in extreme rainfall over India. The analysis of the frequency of rainy days, rain days and heavy rainfall days as well as one-day extreme rainfall and return period has been carried out in this study to observe the impact of climate change on extreme rainfall events and flood risk in India. The frequency of heavy rainfall events are decreasing in major parts of central and north India while they are increasing in peninsular, east and north east India. The study tries to bring out some of the interesting findings which are very useful for hydrological planning and disaster managements. Extreme rainfall and flood risk are increasing significantly in the country except some parts of central India.

  13. Impact of tropical cyclones on modeled extreme wind-wave climate

    NASA Astrophysics Data System (ADS)

    Timmermans, Ben; Stone, Dáithí; Wehner, Michael; Krishnan, Harinarayan

    2017-02-01

    The effect of forcing wind resolution on the extremes of global wind-wave climate are investigated in numerical simulations. Forcing winds from the Community Atmosphere Model at horizontal resolutions of ˜1.0° and ˜0.25° are used to drive Wavewatch III. Differences in extreme wave height are found to manifest most strongly in tropical cyclone (TC) regions, emphasizing the need for high-resolution forcing in those areas. Comparison with observations typically show improvement in performance with increased forcing resolution, with a strong influence in the tail of the distribution, although simulated extremes can exceed observations. A simulation for the end of the 21st century under a RCP 8.5 type emission scenario suggests further increases in extreme wave height in TC regions.

  14. 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

  15. 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

  16. 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.

  17. 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).

  18. The effects of climate change and extreme wildfire events on runoff erosion over a mountain watershed

    Treesearch

    Mingliang Liu; Michael E. Barber; Keith A. Cherkauer; Pete Robichaud; Jennifer C. Adam

    2016-01-01

    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...

  19. Climate change and fetal health: The impacts of exposure to extreme temperatures in New York City.

    PubMed

    Ngo, Nicole S; Horton, Radley M

    2016-01-01

    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. 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). 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. 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 4.6g in the business-as-usual scenario. Results suggest that increasing heat events from climate change could adversely impact birth weight and vary by SES. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. 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.

  1. 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.

  2. 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.

  3. Assessment of the uncertainty in future projection for summer climate extremes over the East Asia

    NASA Astrophysics Data System (ADS)

    Park, Changyong; Min, Seung-Ki; Cha, Dong-Hyun

    2017-04-01

    Future projections of climate extremes in regional and local scales are essential information needed for better adapting to climate changes. However, future projections hold larger uncertainty factors arising from internal and external processes which reduce the projection confidence. Using CMIP5 (Coupled Model Intercomparison Project Phase 5) multi-model simulations, we assess uncertainties in future projections of the East Asian temperature and precipitation extremes focusing on summer. In examining future projection, summer mean and extreme projections of the East Asian temperature and precipitation would be larger as time. Moreover, uncertainty cascades represent wider scenario difference and inter-model ranges with increasing time. A positive mean-extreme relation is found in projections for both temperature and precipitation. For the assessment of uncertainty factors for these projections, dominant uncertainty factors from temperature and precipitation change as time. For uncertainty of mean and extreme temperature, contributions of internal variability and model uncertainty declines after mid-21st century while role of scenario uncertainty grows rapidly. For uncertainty of mean precipitation projections, internal variability is more important than the scenario uncertainty. Unlike mean precipitation, extreme precipitation shows that the scenario uncertainty is expected to be a dominant factor in 2090s. The model uncertainty holds as an important factor for both mean and extreme precipitation until late 21st century. The spatial changes for the uncertainty factors of mean and extreme projections generally are expressed according to temporal changes of the fraction of total variance from uncertainty factors in many grids of the East Asia. ACKNOWLEDGEMENTS The research was supported by the Korea Meteorological Administration Research and Development program under grant KMIPA 2015-2083 and the National Research Foundation of Korea Grant funded by the Ministry of

  4. A spring-summer dichotomy in temperate ecosystem productivity extremes in response to changing climate drivers

    NASA Astrophysics Data System (ADS)

    Sippel, S.; Otto, F. E. L.; Rammig, A.; Reichstein, M.; Mahecha, M. D.

    2016-12-01

    Climate is a major driver of variability and extremes in the functioning of terrestrial ecosystems. A changing climate might thus induce substantial changes in ecosystem carbon and water cycling, often implying previously unseen extreme conditions. However, these ecosystem impacts occur typically through various complex pathways and are thus often not straightforward to quantify, predict or attribute to specific drivers. Here, we demonstrate based on a very large ensemble of process-oriented model simulations, combined with data-driven evidence, that extremes in ecosystem carbon cycling in six eco-physiologically distinct European regions show consistent, but seasonally contrasting trends. In particular, positive and negative carbon cycle anomalies in spring show a consistent trend towards increased gross and net spring carbon uptake. In contrast, negative summer anomalies in gross primary productivity (GPP) and net ecosystem productivity (NEP) show close-to-neutral or negative trends across all six regions (while positive anomalies show partly increasing trends). We show that these contrasting trends imply a partial compensation of drought and heat-induced GPP/NEP reductions in summer by increased carbon uptake in spring. Both empirical evidence and factorial model runs indicate that this apparent `spring-summer dichotomy' is predominantly driven by contrasting responses of European ecosystems to warming. Our findings rely on a very large ensemble of bias-corrected regional climate simulations over Europe. These simulations are used to derive, for each region, an unprecedentedly large ensemble (n=12000 members) of i) process-oriented biosphere model (LPJmL) simulations, and ii) a data-driven proxy of vegetation productivity (the `Fraction of Absorbed Photosynthetic Active Radiation, FPAR'). To disentangle individual climatic drivers of change in the process-oriented and data-driven ensemble, we introduce a simple statistical attribution framework. In conclusion

  5. 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

  6. The effect of climate change on extreme waves in front of the Dutch coast

    NASA Astrophysics Data System (ADS)

    de Winter, Renske C.; Sterl, Andreas; de Vries, Johannes W.; Weber, Susanne L.; Ruessink, Gerben

    2012-08-01

    Coastal safety may be influenced by climate change, as changes in wave conditions (height, period, direction) may increase the vulnerability of dunes and other coastal defences. Dune erosion depends on mean water level, storm surge height and wave conditions. In this paper, we investigate the change in wave conditions in the North Sea in a changing climate. Until now, the effect of climate change on annual maximum wave conditions has been investigated, while events with higher return periods are actually most damaging for the coast (e.g. severe dune erosion). Here, we use the 17-member Ensemble SimulationS of Extreme weather under Non-linear Climate changeE (ESSENCE) change of climate change simulations, to analyse A1b-induced changes in the mean wave climate, the annual maxima and wave conditions with return periods of up to 1:10,000 years in front of the Dutch coast. The mean wave climate is not projected to differ between 1961-1990 and 2071-2100, with both wave height ( H s) and wave period ( T m) remaining unaltered. In the annual maximum conditions, a decrease is projected; especially, the annual T m maximum decreases significantly by 0.3 to 0.6 s over the whole study area. Furthermore, we find that the direction of the annual maximum wave conditions shifts from north and north-west to west and south-west for both H s and T m. This is induced by a similar shift in the direction of the extreme wind speeds. Despite the decrease in annual maximum conditions, the return H s and T m are not projected to change significantly as a result of climate change in front of the Dutch coast for the period 2071-2100 relative to 1961-1990.

  7. How reliable are the estimates of climate variability in extreme precipitation?

    NASA Astrophysics Data System (ADS)

    Zolina, O.; Simmer, C.; Gulev, S.

    2009-09-01

    Existing estimates of climate variability and trends in precipitation extremes are highly uncertain when quantified from daily and higher resolution rain gauge observations. The major sources of uncertainties are associated with the conceptual definition of extreme precipitation, inhomogeneity of different data types and inaccuracy of statistical methods applied for estimation of precipitation extremes. We assess the impact of these uncertainties on climate variability in extreme precipitation over European continent using different collections of European rain gauge data. We try to discriminate the role of changing precipitation totals and varying characteristics of frequency distributions in forming observed changes in precipitation extremes. These two factors have strong seasonal dependence over Europe with winter growth up to 5% per decade being associated with change in precipitation distribution and summer decrease of 3% per decade primarily implied by changes in total. Changes in extreme precipitation in Western Europe are primarily dominated by frequency distribution characteristics while in the Eastern Europe they are closely linked to the changes in totals. Considering limitations of precipitation metrics based on raw data, we argue for the revision of extreme precipitation indices whose applicability is conditioned by the finite number of wet days and propose a set of new indices based on the newly derived distribution of fractional contribution (DFC) of daily precipitation to the total. The extended indices are more stable compared to the routine ones. In winter new set of indices clearly reveals an increasing occurrence of extreme precipitation in Western European Russia (up to 4% per decade) while during summer a downward tendency in the fractional contribution of very wet days is found in Central Western Europe. Newly established indices also allow to better associate European extreme precipitation with the North Atlantic Oscillation and associated

  8. Know your limits? Climate extremes impact the range of Scots pine in unexpected places.

    PubMed

    Julio Camarero, J; Gazol, Antonio; Sancho-Benages, Santiago; Sangüesa-Barreda, Gabriel

    2015-11-01

    Although extreme climatic events such as drought are known to modify forest dynamics by triggering tree dieback, the impact of extreme cold events, especially at the low-latitude margin ('rear edge') of species distributional ranges, has received little attention. The aim of this study was to examine the impact of one such extreme cold event on a population of Scots pine (Pinus sylvestris) along the species' European southern rear-edge range limit and to determine how such events can be incorporated into species distribution models (SDMs). A combination of dendrochronology and field observation was used to quantify how an extreme cold event in 2001 in eastern Spain affected growth, needle loss and mortality of Scots pine. Long-term European climatic data sets were used to contextualize the severity of the 2001 event, and an SDM for Scots pine in Europe was used to predict climatic range limits. The 2001 winter reached record minimum temperatures (equivalent to the maximum European-wide diurnal ranges) and, for trees already stressed by a preceding dry summer and autumn, this caused dieback and large-scale mortality. Needle loss and mortality were particularly evident in south-facing sites, where post-event recovery was greatly reduced. The SDM predicted European Scots pine distribution mainly on the basis of responses to maximum and minimum monthly temperatures, but in comparison with this the observed effects of the 2001 cold event at the southerly edge of the range limit were unforeseen. The results suggest that in order to better forecast how anthropogenic climate change might affect future forest distributions, distribution modelling techniques such as SDMs must incorporate climatic extremes. For Scots pine, this study shows that the effects of cold extremes should be included across the entire distribution margin, including the southern 'rear edge', in order to avoid biased predictions based solely on warmer climatic scenarios. © The Author 2015. Published by

  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. 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.

  11. 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.

  12. Climate changes in temperature and precipitation extremes in an alpine grassland of Central Asia

    NASA Astrophysics Data System (ADS)

    Hu, Zengyun; Li, Qingxiang; Chen, Xi; Teng, Zhidong; Chen, Changchun; Yin, Gang; Zhang, Yuqing

    2016-11-01

    The natural ecosystem in Central Asia is sensitive and vulnerable to the arid and semiarid climate variations, especially the climate extreme events. However, the climate extreme events in this area are still unclear. Therefore, this study analyzed the climate variability in the temperature and precipitation extreme events in an alpine grassland (Bayanbuluk) of Central Asia based on the daily minimum temperature, daily maximum temperature, and daily precipitation from 1958 to 2012. Statistically significant ( p < 0.01) increasing trends were found in the minimum temperature, maximum temperature at annual, and seasonal time scales except the winter maximum temperature. In the seasonal changes, the winter temperature had the largest contribution to the annual warming. Further, there appeared increasing trends for the warm nights and the warm days and decreasing trends for the cool nights and the cool days at a 99 % confidence level. These trends directly resulted in an increasing trend for the growing season length (GSL) which could have positively influence on the vegetation productivity. For the precipitation, it displayed an increasing trend for the annual precipitation although it was not significant. And the summer precipitation had the same variations as the annual precipitation which indicated that the precipitation in summer made the biggest contribution to the annual precipitation than the other three seasons. The winter precipitation had a significant increasing trend (1.49 mm/10a) and a decreasing trend was found in spring. We also found that the precipitation of the very wet days mainly contributes to the annual precipitation with the trend of 4.5 mm/10a. The maximum 1-day precipitation and the heavy precipitation days only had slight increasing trend. A sharp decreasing trend was found before the early 1980s, and then becoming increase for the above three precipitation indexes. The climate experienced a warm-wet abrupt climate change in the 1980s

  13. Key ecological responses to nitrogen are altered by climate ...

    EPA Pesticide Factsheets

    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. Ecosystems are simultaneously exposed to multiple stressors; two dominant drivers threatening ecosystems are anthropogenic nitrogen loading and climate change. Evaluating the cumulative effects of these stressors provides a holistic view of ecosystem vulnerability, which would better inform policy decisions aimed to protect the sustainability of ecosystems. Our current knowledge of the cumulative effects of these stressors is growing, but limited. The goal of this paper is to synthesize the state of scientific knowledge on how ecosystems are affected by the interactions of meteorlogic/climatic factors (e.g., temperature and precipitation) and nitrogen addition. Understanding the interactions of meteorlogic/climatic factors and nitrogen will help to inform how current and projected variability may affect ecosystem response.

  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. 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.

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

    EPA Pesticide Factsheets

    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. Ecosystems are simultaneously exposed to multiple stressors; two dominant drivers threatening ecosystems are anthropogenic nitrogen loading and climate change. Evaluating the cumulative effects of these stressors provides a holistic view of ecosystem vulnerability, which would better inform policy decisions aimed to protect the sustainability of ecosystems. Our current knowledge of the cumulative effects of these stressors is growing, but limited. The goal of this paper is to synthesize the state of scientific knowledge on how ecosystems are affected by the interactions of meteorlogic/climatic factors (e.g., temperature and precipitation) and nitrogen addition. Understanding the interactions of meteorlogic/climatic factors and nitrogen will help to inform how current and projected variability may affect ecosystem response.

  17. 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.

  18. 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

  19. 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

  20. Changes in Large Spatiotemporal Climatic Extreme Events Beyond the Mean Warming Signal

    NASA Astrophysics Data System (ADS)

    Sippel, S.; Mahecha, M. D.; Otto, F. E. L.

    2014-12-01

    Weather and climate extremes impose substantial impacts on human societies and ecosystems. In particular, events that are large in space (areal extent), time (duration) or both are likely to be associated with highly significant consequences. Hence, a better detection, characterization and understanding of such anomalous events is crucial. There is widespread consensus on a global and continental-scale warming trend, which leads to increases in the number, magnitude and frequency of temperature extremes (Hansen et al., 2012). It is less clear, however, if this warming also coincides with a broadening of temperature distributions (Huntingford et al., 2013). Moreover, the question whether other climate variables, such as large-scale precipitation deficits, likewise change, remains largely unanswered (Sheffield et al., 2012; Seneviratne 2012). In this study, we address this issue by investigating the characteristics of large extremes, using an algorithm that detects the n largest spatiotemporally connected climate extremes for any time period. The deployed algorithm detects, depending on the chosen time step and variable, major heat waves, cold spells or droughts. We find a robust increase in the magnitude of large hot temperature extremes on a global and European scale in observations and reanalysis products, whereas the duration and affected area of those extremes does not show any pronounced changes. These results reveal that there is a detectable signal in temperature distributions beyond the mean warming trend, which might imply a structural change in the making of large extreme events. Furthermore, we use the CMIP5 ensemble of models and an ensemble of 100+ members of a regional climate model for Europe (HadRM3P within the weather@home framework[1]) in order to conduct a global and continental-scale analysis of large extreme events in temperature and precipitation. The employment of those model ensembles allows to sample more reliably the tails of the

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. Controlling a hurricane by altering its internal climate

    NASA Astrophysics Data System (ADS)

    Mardhekar, D.

    2010-09-01

    Atmospheric hazards, like the fury of a hurricane, can be controlled by altering its internal climate. The hurricane controlling technique suggested is eco-friendly, compatible with hurricane size, has a sound scientific base and is practically possible. The key factor is a large scale dilution of the hurricane fuel, vapour, in the eye wall and spiral rain bands where condensation causing vapor volume reduction (a new concept which can be explained by Avogadro's law) and latent heat release drive the storm. This can be achieved by installing multiple storage tanks containing dry liquefied air on the onshore and offshore coastal regions and islands, preferably underground, in the usual path of a hurricane. Each storage tank is designed to hold and release dry liquefied air of around 100,000 tons. Satellite tracking of hurricanes can locate the eye wall and the spiral rain bands. The installed storage tanks coming under these areas will rapidly inject dry air in huge quantities thereby diluting the vapour content of the vapour-rich air in the eye wall and in the spiral rain bands. This will result in reduced natural input of vapour-rich air, reduced release of latent heat, reduced formation of the low pressure zone due to condensation and volume reduction of the vapor, expansion of the artificially introduced dry air as it goes up occupying a larger space with the diluted fuel, absorption of energy from the system by low temperature of the artificially introduced air. It will effect considerable condensation of the vapor near the sea surface thus further starving the hurricane of its fuel in its engine. Seeding materials, or microscopic dust as suggested by Dr. Daniel Rosenfeld in large quantities may also be introduced via the flow of the injected dry air in order to enhance the hurricane controlling ability. All the above factors are in favour of retarding the hurricane's wind speed and power. The sudden weakening of hurricane Lili was found to be partially caused

  6. Assessment of climate variations in temperature and precipitation extreme events over Iran

    NASA Astrophysics Data System (ADS)

    Soltani, M.; Laux, P.; Kunstmann, H.; Stan, K.; Sohrabi, M. M.; Molanejad, M.; Sabziparvar, A. A.; Ranjbar SaadatAbadi, A.; Ranjbar, F.; Rousta, I.; Zawar-Reza, P.; Khoshakhlagh, F.; Soltanzadeh, I.; Babu, C. A.; Azizi, G. H.; Martin, M. V.

    2016-11-01

    In this study, changes in the spatial and temporal patterns of climate extreme indices were analyzed. Daily maximum and minimum air temperature, precipitation, and their association with climate change were used as the basis for tracking changes at 50 meteorological stations in Iran over the period 1975-2010. Sixteen indices of extreme temperature and 11 indices of extreme precipitation, which have been quality controlled and tested for homogeneity and missing data, are examined. Temperature extremes show a warming trend, with a large proportion of stations having statistically significant trends for all temperature indices. Over the last 15 years (1995-2010), the annual frequency of warm days and nights has increased by 12 and 14 days/decade, respectively. The number of cold days and nights has decreased by 4 and 3 days/decade, respectively. The annual mean maximum and minimum temperatures averaged across Iran both increased by 0.031 and 0.059 °C/decade. The probability of cold nights has gradually decreased from more than 20 % in 1975-1986 to less than 15 % in 1999-2010, whereas the mean frequency of warm days has increased abruptly between the first 12-year period (1975-1986) and the recent 12-year period (1999-2010) from 18 to 40 %, respectively. There are no systematic regional trends over the study period in total precipitation or in the frequency and duration of extreme precipitation events. Statistically significant trends in extreme precipitation events are observed at less than 15 % of all weather stations, with no spatially coherent pattern of change, whereas statistically significant changes in extreme temperature events have occurred at more than 85 % of all weather stations, forming strongly coherent spatial patterns.

  7. 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.

  8. Precipitation extremes over La Plata Basin – Review and new results from observations and climate simulations

    SciTech Connect

    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.

  9. Impacts of multi-scale solar activity on climate. Part I: Atmospheric circulation patterns and climate extremes

    NASA Astrophysics Data System (ADS)

    Weng, Hengyi

    2012-07-01

    The impacts of solar activity on climate are explored in this two-part study. Based on the principles of atmospheric dynamics, Part I propose an amplifying mechanism of solar impacts on winter climate extremes through changing the atmospheric circulation patterns. This mechanism is supported by data analysis of the sunspot number up to the predicted Solar Cycle 24, the historical surface temperature data, and atmospheric variables of NCEP/NCAR Reanalysis up to the February 2011 for the Northern Hemisphere winters. For low solar activity, the thermal contrast between the low- and high-latitudes is enhanced, so as the mid-latitude baroclinic ultra-long wave activity. The land-ocean thermal contrast is also enhanced, which amplifies the topographic waves. The enhanced mid-latitude waves in turn enhance the meridional heat transport from the low to high latitudes, making the atmospheric "heat engine" more efficient than normal. The jets shift southward and the polar vortex is weakened. The Northern Annular Mode (NAM) index tends to be negative. The mid-latitude surface exhibits large-scale convergence and updrafts, which favor extreme weather/climate events to occur. The thermally driven Siberian high is enhanced, which enhances the East Asian winter monsoon (EAWM). For high solar activity, the mid-latitude circulation patterns are less wavy with less meridional transport. The NAM tends to be positive, and the Siberian high and the EAWM tend to be weaker than normal. Thus the extreme weather/climate events for high solar activity occur in different regions with different severity from those for low solar activity. The solar influence on the midto high-latitude surface temperature and circulations can stand out after removing the influence from the El Niño-Southern Oscillation. The atmospheric amplifying mechanism indicates that the solar impacts on climate should not be simply estimated by the magnitude of the change in the solar radiation over solar cycles when it is

  10. Using Critical Thresholds to Customize Climate Projections of Extreme Events to User Needs and Support Decisions

    NASA Astrophysics Data System (ADS)

    Garfin, G. M.; Petersen, A.; Shafer, M.; MacClune, K.; Hayhoe, K.; Riley, R.; Nasser, E.; Kos, L.; Allan, C.; Stults, M.; LeRoy, S. R.

    2016-12-01

    Many communities in the United States are already vulnerable to extreme events; many of these vulnerabilities are likely to increase with climate change. In order to promote the development of effective community responses to climate change, we tested a participatory process for developing usable climate science, in which our project team worked with decision-makers to identify extreme event parameters and critical thresholds associated with policy development and adaptation actions. Our hypothesis is that conveying climate science and data through user-defined parameters and thresholds will help develop capacity to streamline the use of climate projections in developing strategies and actions, and motivate participation by a variety of preparedness planners. Our team collaborated with urban decision-makers, in departments that included resilience, planning, public works, public health, emergency management, and others, in four cities in the semi-arid south-central plains and intermountain areas of Colorado, New Mexico, Oklahoma, and Texas. Through an iterative process, we homed in on both simple and hybrid indicators for which we could develop credible city-specific projections, to stimulate discussion about adaptation actions; throughout the process, we communicated information about confidence and uncertainty, in order to develop a blend of historic and projected climate data, as appropriate, depending on levels of uncertainty. Our collaborations have resulted in (a) the identification of more than 50 unique indicators and thresholds across the four communities, (b) the development of adaptation action strategies in each community, and (c) the implementation of actions, ranging from a climate leadership training program for city staff members, to a rainwater capture project to improve responses to expected increases in both stormwater runoff and water capture for drought episodes.

  11. Bias-Correction of Extreme Temperatures and Precipitation in NA-CORDEX Regional Climate Model Output

    NASA Astrophysics Data System (ADS)

    McGinnis, S. A.; Mearns, L.

    2016-12-01

    Climate model outputs typically contain significant biases that can hinder their use in impacts analysis. Frequently, these biases are non-linear, and have a greater effect in the tails of the distribution than they do near the mean. Extremes of temperature and precipitation also have a disproportionate effect on the impacts of climate, making it important to understand and correct biases across the entire distribution of values for use in climate change impacts analysis.Analysis of various bias correction methodologies by Teutschbein & Seibert (2012) showed that distribution mapping has the best overall performance. Further work by McGinnis, et al. (2015) has shown that kernel density distribution mapping (KDDM) outperforms other distribution mapping techniques, and that it provides effective correction of extremes that simple mean and variance adjustments cannot.We use KDDM to bias-correct daily minimum and maximum temperatures and precipitation from NA-CORDEX, the North American branch of CORDEX, the COordinated Regional Downscaling EXperiment, which nests high-resolution regional climate models (RCMs) within general circulation models (GCMs) over a limited domain. We bias-correct the model output against the University of Idaho's METDATA high-resolution gridded daily observational dataset (Abatzoglou, 2012). We then examine the resulting changes to the climate change signal in the bulk and in the tails of the distribution of values.The structure of the NA-CORDEX experiment allows us to compare the effects of bias correction on the climate change signal at two different spatial resolutions (25 km and 50 km), for different emissions scenarios (RCP 4.5 and RCP 8.5), and for multiple different combinations of regional climate model and driving global model.

  12. 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.

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

    PubMed Central

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

    2016-01-01

    The desire to use sentinel species as early warning indicators of impending climate change effects on entire ecosystems is attractive, but we need to verify that such approaches have sound biological foundations. A recent large-scale warming event in the North Pacific Ocean of unprecedented magnitude and duration allowed us to evaluate the sentinel status of giant kelp, a coastal foundation species that thrives in cold, nutrient-rich waters and is considered sensitive to warming. Here, we show that giant kelp and the majority of species that associate with it did not presage ecosystem effects of extreme warming off southern California despite giant kelp's expected vulnerability. Our results challenge the general perception that kelp-dominated systems are highly vulnerable to extreme warming events and expose the more general risk of relying on supposed sentinel species that are assumed to be very sensitive to climate change. PMID:27958273

  14. WRF-Cordex simulations for Europe: mean and extreme precipitation for present and future climates

    NASA Astrophysics Data System (ADS)

    Cardoso, Rita M.; Soares, Pedro M. M.; Miranda, Pedro M. A.

    2013-04-01

    The Weather Research and Forecast (WRF-ARW) model, version 3.3.1, was used to perform the European domain Cordex simulations, at 50km resolution. A first simulation, forced by ERA-Interim (1989-2009), was carried out to evaluate the models performance to represent the mean and extreme precipitation in present European climate. This evaluation is based in the comparison of WRF results against the ECAD regular gridded dataset of daily precipitation. Results are comparable to recent studies with other models for the European region, at this resolution. For the same domain a control and a future scenario (RCP8.5) simulation was performed to assess the climate change impact on the mean and extreme precipitation. These regional simulations were forced by EC-EARTH model results, and, encompass the periods from 1960-2006 and 2006-2100, respectively.

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

    PubMed

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

    2016-12-13

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

  17. 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

  18. Projected changes in regional climate extremes arising from Arctic sea ice loss

    NASA Astrophysics Data System (ADS)

    Screen, James A.; Deser, Clara; Sun, Lantao

    2015-08-01

    The decline in Arctic sea ice cover has been widely documented and it is clear that this change is having profound impacts locally. An emerging and highly uncertain area of scientific research, however, is whether such Arctic change has a tangible effect on weather and climate at lower latitudes. Of particular societal relevance is the open question: will continued Arctic sea ice loss make mid-latitude weather more extreme? Here we analyse idealized atmospheric general circulation model simulations, using two independent models, both forced by projected Arctic sea ice loss in the late twenty-first century. We identify robust projected changes in regional temperature and precipitation extremes arising solely due to Arctic sea ice loss. The likelihood and duration of cold extremes are projected to decrease over high latitudes and over central and eastern North America, but to increase over central Asia. Hot extremes are projected to increase in frequency and duration over high latitudes. The likelihood and severity of wet extremes are projected to increase over high latitudes, the Mediterranean and central Asia; and their intensity is projected to increase over high latitudes and central and eastern Asia. The number of dry days over mid-latitude Eurasia and dry spell duration over high latitudes are both projected to decrease. There is closer model agreement for projected changes in temperature extremes than for precipitation extremes. Overall, we find that extreme weather over central and eastern North America is more sensitive to Arctic sea ice loss than over other mid-latitude regions. Our results are useful for constraining the role of Arctic sea ice loss in shifting the odds of extreme weather, but must not be viewed as deterministic projections, as they do not account for drivers other than Arctic sea ice loss.

  19. 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

  20. Hydro-meteorological extreme events caused by climate variability or change and their impacts on infrastructures

    NASA Astrophysics Data System (ADS)

    Ganguly, A. R.

    2008-05-01

    Critical infrastructures and key assets, especially along coastal areas, are vulnerable to sea level rise caused by climate change, and perhaps more importantly, to extremes of precipitation, wind and storm surges, which in turn are likely to be exacerbated by climate change and consequent rise in sea levels. The 2007 IPCC report states that extreme hydro-meteorological events, ranging from heat waves and cold spells to extreme rainfall events or ice storms, are likely to increase in intensity, duration and frequency over the next several decades. While the uncertainties in our current understanding of climate impacts on certain weather extremes like hurricanes may be high, the net damage in the future is expected to increase anyway owing to enhanced stresses caused by population growth and land use changes. The first step is to quantify the expected exacerbation in the intensity- duration-frequency (IDF) of extreme weather and hydrologic events in light of climate change and assess the uncertainties thereof. Climate model projections need to be developed or downscaled at regional to local scales relevant to the scales of such hazards and their impacts on infrastructures and their interdependencies. The second step is to quantify the expected impact on infrastructures caused by the exacerbated hazards. Thus, infrastructures designed to outlast specific return levels of precipitation or wind may be under additional stress if climate change causes the return levels to intensify. The third step is to develop precise and dynamic geospatial risk indices. The risk computations need to consider the IDF of weather or hydrologic hazards, aggregate measures of infrastructure resilience and vulnerability, the consequences of infrastructure damage on population, economy and environment, and the capabilities and measures that can be brought to bear to mitigate the risks. One additional requirement is to investigate specific infrastructures in more depth and quantify the

  1. Climate projections of future extreme events accounting for modelling uncertainties and historical simulation biases

    NASA Astrophysics Data System (ADS)

    Brown, Simon J.; Murphy, James M.; Sexton, David M. H.; Harris, Glen R.

    2014-11-01

    A methodology is presented for providing projections of absolute future values of extreme weather events that takes into account key uncertainties in predicting future climate. This is achieved by characterising both observed and modelled extremes with a single form of non-stationary extreme value (EV) distribution that depends on global mean temperature and which includes terms that account for model bias. Such a distribution allows the prediction of future "observed" extremes for any period in the twenty-first century. Uncertainty in modelling future climate, arising from a wide range of atmospheric, oceanic, sulphur cycle and carbon cycle processes, is accounted for by using probabilistic distributions of future global temperature and EV parameters. These distributions are generated by Bayesian sampling of emulators with samples weighted by their likelihood with respect to a set of observational constraints. The emulators are trained on a large perturbed parameter ensemble of global simulations of the recent past, and the equilibrium response to doubled CO2. Emulated global EV parameters are converted to the relevant regional scale through downscaling relationships derived from a smaller perturbed parameter regional climate model ensemble. The simultaneous fitting of the EV model to regional model data and observations allows the characterisation of how observed extremes may change in the future irrespective of biases that may be present in the regional models simulation of the recent past climate. The clearest impact of a parameter perturbation in this ensemble was found to be the depth to which plants can access water. Members with shallow soils tend to be biased hot and dry in summer for the observational period. These biases also appear to have an impact on the potential future response for summer temperatures with some members with shallow soils having increases for extremes that reduce with extreme severity. We apply this methodology for London, using the

  2. 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