WorldWideScience

Sample records for extreme climatic indices

  1. Financial market response to extreme events indicating climatic change

    Science.gov (United States)

    Anttila-Hughes, J. K.

    2016-05-01

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

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

    Science.gov (United States)

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

    2013-03-01

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

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

    Science.gov (United States)

    Zarekarizi, Mahkameh; Rana, Arun; Moradkhani, Hamid

    2016-04-01

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

  4. Analyses of climate and extreme indices in Central and Eastern Europe within the CECILIA project

    Science.gov (United States)

    Hirschi, M.; Boberg, F.; Christensen, O. B.; Seneviratne, S. I.; Stepanek, P.; Wp4 Members, Cecilia

    2009-04-01

    The EU-project CECILIA (Central and Eastern Europe Climate Change Impact and VulnerabiLIty Assessment) aims at delivering a climate change impacts and vulnerability assessment in targeted areas of Central and Eastern Europe. This region appears particularly vulnerable with regard to future changes in extremes (Christensen and Christensen 2003, Schär et al. 2004), likely due to regional specificities such as highly varying topography and continentality, and due to changes in soil moisture content (Seneviratne et al. 2006). In the project, emphasis is given to applications of regional climate modeling studies at a resolution of 10 km for local impact studies in key sectors of the region. The project includes the analysis of extreme weather events in present day and future climate in the target region. For this purpose, an extensive list of precipitation and temperature indices was defined. Observational data used for the indices calculation comes from the European Climate Assessment & Dataset project (ECA&D, Klein Tank et al. 2002), from the ENSEMBLES gridded observations (E-Obs, Haylock et al. 2008), and from station data of the local partners in Central and Eastern Europe. Moreover, the same indices were calculated consistently for a selection of pre-existing RCM datasets (PRUDENCE, ENSEMBLES), and for the CECILIA driving models. Later on, the 10 km high-resolution climate simulations from CECILIA will be included in the analysis. Here we focus on the analysis of a selection of temperature indices, and on the validation of the model-derived indices with the observations. Generally, the spatial agreement between the models and the observations is very good for mean, maximum and minimum temperature (both in terms of the spatial variability and the spatial correlation). The spread between the models is larger for the daily temperature range, with most models showing larger spatial variability compared to the observations. When it comes to heat and cold wave indices

  5. Max-stable based evaluation of impacts of climate indices on extreme precipitation processes across the Poyang Lake basin, China

    Science.gov (United States)

    Zhang, Qiang; Xiao, Mingzhong; Singh, Vijay P.; Chen, Yongqin David

    2014-11-01

    Monthly precipitation extremes defined by monthly maximum one-day precipitation amount (Rx1day) and maximum consecutive five-day precipitation amount (Rx5day) were analyzed based on daily precipitation data covering a period of 1957 to 2010 across the Poyang Lake basin, the largest freshwater lake basin in the lower Yangtze River basin, China. Based on the max-stable, impacts of El Niño-Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Indian Ocean Dipole (IOD), Pacific Decadal Oscillation (PDO) on the annual and seasonal Rx1day and Rx5day regimes in the Poyang Lake basin were evaluated. Results indicated that annual Rx1day and Rx5day were influenced mainly by the ENSO events a year earlier and the relations between annual Rx1day and Rx5day and ENSO were statistically positive. However, influences of climate indices on the seasonal Rx1day and Rx5day are complicated when compared with the influences on annual Rx1day and Rx5day regimes. ENSO and PDO can enhance the spring Rx1day regime of the subsequent year and the same year, respectively, but IOD weakens spring Rx1day in the same year. In summer, ENSO can enhance Rx1day of the subsequent year. However, Rx1day in summer had a decreasing tendency. IOD and NAO influenced the autumn Rx1day in another way, i.e., IOD decreases autumn Rx1day of the subsequent year; while NAO enhances autumn Rx1day of the same year. Meanwhile, ENSO can amplify the summer Rx1day in terms of variability, while IOD and NAO can, respectively, influence autumn and winter Rx1day in terms of mean. Influences of climate indices on annual and seasonal Rx5day are similar to those on Rx1day. Results of this study are of great theoretical as well as practical merit in terms of evaluation of droughts and floods under the influences of climate indices.

  6. Climate Change Indicators

    Science.gov (United States)

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

  7. EXTREME WINTERS IN XX–XXI CENTURIES AS INDICATORS OF SNOWINESS AND AVALANCHE HAZARD IN THE PAST AND EXPECTED CLIMATE CHANGE CONDITIONS

    Directory of Open Access Journals (Sweden)

    A. D. Oleynikov

    2012-01-01

    Full Text Available Currently, due to the global climate change and increasing frequency of weather events focus is on prediction of climate extremes. Large-scale meteorological anomalies can cause long-term paralysis of social and economic infrastructure of the major mountain regions and even individual states. In winter periods, these anomalies are associated with prolonged heavy snowfalls and associated with them catastrophic avalanches which cause significant social and economic damage. The climate system maintains a certain momentum during periods of adjustment and transition to other conditions in the ratio of heat and moisture and contains a climate «signal» of the climates of the past and the future. In our view seasonal and yearly extremes perform the role of these indicators, study of which enables for a deeper understanding and appreciation of the real situation of the climate periods related to the modern ones. The paper provides an overview of the criteria for selection of extreme winters. Identification of extremely cold winters during the period of instrumental observation and assessment of their snowiness and avalanche activity done for the Elbrus region, which is a model site for study of the avalanche regime in the Central Caucasus. The studies aim to identify the extreme winters in the Greater Caucasus, assess their frequency of occurrence, characterize the scale and intensity of the avalanche formation. The data obtained can be used to identify winter-analogues in the reconstruction and long-term forecast of avalanches. 

  8. Precipitation extremes under climate change

    CERN Document Server

    O'Gorman, Paul A

    2015-01-01

    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...

  9. Changes of reanalysis-derived Northern Hemisphere summer warm extreme indices during 1948-2006 and links with climate variability

    Science.gov (United States)

    Fang, Xingqin; Wang, Anyu; Fong, Soi-kun; Lin, Wenshi; Liu, Ji

    2008-08-01

    Using1948-2006 surface 2 m daily temperature, daily maximum temperature and daily minimum temperature of National Centers for Environmental Prediction (NCEP) reanalysis dataset, summer warm extreme indices, warm days (TG90P), warm-spell days (WSFI), warm day-times (TX90P) and warm nights (TN90P) are calculated for Gaussian grids, a complete Northern Hemisphere (NH) picture of changes of summer warm extremes is presented, and their links with El Niño/La Niña & Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO) and North Atlantic Oscillation (NAO) are also examined in this paper. The results on the NH summer seasonal basis are as follows. Warm days, warm-spell days, warm day-times and warm nights increase at rates of 2.18, 1.23, 2.31 and 2.00 days/decade respectively during 1948-2006. A broader area is exposed to frequent occurrence of warm extremes in the recent 30 years than in the last 30 years. The 59-year long-term upward trend is characterized by a positive trend reversion in the late 1970s, with a slight downward trend in the last 30 years and a rapid upward trend in the recent 30 years, representing the main form of interdecadal variance of NH warm extremes. Warm days, warm-spell days, warm day-times and warm nights increase at rates of 4.53, 3.36, 4.44 and 4.21 days/decade respectively during 1977-2006. During 1948-2006, the largest increasing rate is at central tropical Atlantic and the largest decreasing rate in Mongolia and north China. Significant (level of 0.05) upward trends cover about half of the NH during 1948-2006 and about a third of the NH during 1977-2006 with the very significant upward trends more focused, while very sparse regions have significant downward trends during these two periods. In the recent 30 years, although NH-land summer warms at a faster rate than NH-water, warm extremes on NH-water increase much faster than those on NH-land, the average warm extreme indices and their increasing trends on NH are most modulated by

  10. Weather and Climate Extremes.

    Science.gov (United States)

    1997-09-01

    Antarctica’s highest (New Zealand Antarctic Society, 1974). This extreme exceeded the record of 58°F (14.4°C) that occurred on 20 October 1956 at Esperanza ... Esperanza (also known as Bahia Esperanza , Hope Bay) was in operation from 1945 through the early 1960s. Meteorological/Climatological Factors: This extreme...cm) Location: Grand Ilet, La R’eunion Island [21°00’S, 55°30’E] Date: 26 January 1980 WORLD’S GREATEST 24-HOUR RAINFALL 72 in (182.5 cm

  11. The Pace of Perceivable Extreme Climate Change

    Science.gov (United States)

    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.

  12. Historical influence of irrigation on climate extremes

    Science.gov (United States)

    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.

  13. Assessing Climate Variability using Extreme Rainfall and ...

    African Journals Online (AJOL)

    user1

    As noted by the Bureau of Meteorology, Canada, to examine whether such ... their local climate, a threshold considered extreme in one part of Australia could be ... (extreme frequency); the average intensity of rainfall from extreme events.

  14. Climate as an indicator

    NARCIS (Netherlands)

    Wassink, J.

    2011-01-01

    They both have Delft roots, but their standpoints in the climate discussion are by no means similar: Professor Pier Vellinga worried publicly, whereas Professor Salle Kroonenberg qualified climate change. Strangely enough, they do agree on the solutions. “If you take a long, hard look,” Prof. Vellin

  15. Climate indices for vulnerability assessments

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-08-15

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

  16. Research progress of extreme climate and its vegetation response

    Science.gov (United States)

    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.

  17. Evaluation of climate extremes in the CMIP5 model simulations

    Science.gov (United States)

    Sillmann, J.; Kharin, S.; Zhang, X.; Zwiers, F. W.

    2011-12-01

    Climate extremes manifest an important aspect of natural climate variability and anthropogenic climate change. To minimize human and financial losses caused by extreme events it is important to have reliable projections of their occurrence and intensity. State-of-the-art global climate models represented by the CMIP5 model ensemble are widely used as tools to simulate the present and project the future climate. Thus, it is crucial to get an understanding of how well climate extremes are simulated by these models in the present climate to be able to appraise their usefulness for future projections. We calculated a global set of well-defined indices for climate extremes based on daily temperature and precipitation data with the available CMIP5 models and use the indices to present a first-order evaluation of the model performance in comparison with re-analysis and a gridded observational dataset. We also focus our analysis on regional aspects of the model performance. Some of the indices are based on threshold exceedance, i.e. percentage of days below the 10th or above the 90th percentile of the maximum and minimum temperature. These indices require special attention for model evaluation as by definition the threshold exceedance is approximately 10% for individual models, re-analysis, and observations. We introduce a novel method to evaluate the model performance particular for these indices.

  18. Is climate change modifying precipitation extremes?

    Science.gov (United States)

    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.

  19. Climate extremes and the carbon cycle (Invited)

    Science.gov (United States)

    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. Extreme climate. Blessing and curse

    Energy Technology Data Exchange (ETDEWEB)

    Forst, Michael

    2010-07-01

    While the commercial and banking centre Dubai finds itself dealing with the aftermath of the economic crisis, the conservative neighbour Abu Dhabi is already pursuing ambitious targets - but the climate conditions in the desert states are not always ideal for the utilization of renewable energies. (orig.)

  1. Extreme wind speeds in mixed climates revisited

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Nicholas J.; Ian Harris, R. [Anemos Associates Ltd., 14 The Chestnuts, Hemel Hempstead HP3 0DZ (United Kingdom); Whiting, Richard [Department of Aerospace, University of Bristol, Bristol BS8 1TR (United Kingdom)

    2003-02-01

    The methodology for the analysis of extreme wind speeds in mixed climates originally proposed in 1978 by Gomes and Vickery is updated to take advantage of recent improvements in methodology and available data records. The revised methodology is demonstrated for two sites in Australia: Onslow and Brisbane. This work shows that the observed curvature in the upper tail is due to incomplete convergence to the Fisher-Tippett Type 1 asymptote and is not an indicator of Type 3 behaviour as sometimes supposed. It is also shown that moving from a reference epoch of 1 year to an epoch of 50 years frees the method from most of the rate-dependent assumptions, and simplifies the problem to a single, dominant wind mechanism.

  2. Extreme Weather Events and Climate Change Attribution

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Katherine [National Academy of Sciences, Washington, DC (United States)

    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.

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

    Science.gov (United States)

    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.

  4. Community responses to extreme climatic conditions

    Directory of Open Access Journals (Sweden)

    Frédéric JIGUET, Lluis BROTONS, Vincent DEVICTOR

    2011-06-01

    Full Text Available Species assemblages and natural communities are increasingly impacted by changes in the frequency and severity of extreme climatic events. Here we propose a brief overview of expected and demonstrated direct and indirect impacts of extreme events on animal communities. We show that differential impacts on basic biological parameters of individual species can lead to strong changes in community composition and structure with the potential to considerably modify the functional traits of the community. Sudden disequilibria have even been shown to induce irreversible shifts in marine ecosystems, while cascade effects on various taxonomic groups have been highlighted in Mediterranean forests. Indirect effects of extreme climatic events are expected when event-induced habitat changes (e.g. soil stability, vegetation composition, water flows altered by droughts, floods or hurricanes have differential consequences on species assembled within the communities. Moreover, in increasing the amplitude of trophic mismatches, extreme events are likely to turn many systems into ecological traps under climate change. Finally, we propose a focus on the potential impacts of an extreme heat wave on local assemblages as an empirical case study, analysing monitoring data on breeding birds collected in France. In this example, we show that despite specific populations were differently affected by local temperature anomalies, communities seem to be unaffected by a sudden heat wave. These results suggest that communities are tracking climate change at the highest possible rate [Current Zoology 57 (3: 406–413, 2011].

  5. Community responses to extreme climatic conditions

    Institute of Scientific and Technical Information of China (English)

    Frédéric JIGUET; Lluis BROTONS; Vincent DEVICTOR

    2011-01-01

    Species assemblages and natural communities are increasingly impacted by changes in the frequency and severity of extreme climatic events. Here we propose a brief overview of expected and demonstrated direct and indirect impacts of extreme events on animal communities. We show that differential impacts on basic biological parameters of individual species can lead to strong changes in community composition and structure with the potential to considerably modify the functional traits of the community. Sudden disequilibria have even been shown to induce irreversible shifts in marine ecosystems, while cascade effects on various taxonomic groups have been highlighted in Mediterranean forests. Indirect effects of extreme climatic events are expected when event-induced habitat changes (e.g. Soil stability, vegetation composition, water flows altered by droughts, floods or hurricanes) have differential consequences on species assembled within the communities. Moreover, in increasing the amplitude of trophic mismatches, extreme events are likely to turn many systems into ecological traps under climate change. Finally, we propose a focus on the potential impacts of an extreme heat wave on local assemblages as an empirical case study, analysing monitoring data on breeding birds collected in France. In this example, we show that despite specific populations were differently affected by local temperature anomalies, communities seem to be unaffected by a sudden heat wave. These results suggest that communities are tracking climate change at the highest possible rate.

  6. Observed and Projected Climate Extremities in Chennai Metropolitan Area

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  9. 北京1960-2008年气候变暖及极端气温指数变化特征%Characteristics of Climate Warming and Extreme Temperature Indices in Beijing over 1960-2008

    Institute of Scientific and Technical Information of China (English)

    郑祚芳; 丁海燕; 范水勇

    2011-01-01

    应用均一化逐日气象观测资料,分析了北京地区1960-2008年气候变暖及主要极端气温指数的统计特征.结果表明:近49年来北京年平均气温增温速率约为0.39℃/10a,最高,最低气温变化具有明显的非对称性.霜冻日数和气温年较差呈现下降趋势,暖夜指数及热浪指数呈现上升趋势,除气温年较差外,其他极端气温指数的气候变率均在加大.北京年平均气温及极端气温指数主要存在21年、15~17年及准10年周期特征.年平均气温与极端气温指数之间存在较强相关性,气候变暖突变发生前后某些极端气温指数发生频率表现出明显差异.自1980年起,北京市区极端最高气温及其增温率明显高于近郊和远郊,高温日数市区多于近郊,近郊多于远郊,近、远郊极端最低气温温差高于城、近郊温差.%Using the homogenized temperature data series in the period 1960-2008, the characteristics of climate warming and variations of extreme temperature indices in Beijing were analyzed.Results indicate that the increase rate of annual mean temperature were 0.39℃/10a, and the mean maximum and minimum temperatures changed asymmetrically, indicating that the climate warming were mainly caused by minimum temperature increasing.The climate base state indices of frost days (FD) and extreme temperature range (ETR) declined, warm nights (TN90) and heat wave duration index (HWDI) increased, and most of extreme temperature indices exhibited high variability except for the ETR index.Morlet wavelet transform shows that the main periods for mean annual temperature and extreme temperature indices were about 21, 15-17, and 10 years.There were a close correlation between annual mean temperature and extreme temperature indices.Since 1980, extreme high temperature, and high temperature days have increased more in urban areas than in suburbs and exurbs, while extreme low temperature and low temperature days have decreased more in

  10. Coping with extreme climate events: Institutional flocking

    NARCIS (Netherlands)

    Koppen, van C.S.A.; Mol, A.P.J.; Tatenhove, van J.P.M.

    2010-01-01

    The article explores the governance structures that would be needed to cope with extreme and unpredictable climate change. The impacts on the Netherlands of a Gulf Stream collapse in the Northern Atlantic are taken as a case. This hypothetical situation of serious risks and high uncertainties requir

  11. Coping with extreme climate events: Institutional flocking

    NARCIS (Netherlands)

    Koppen, van C.S.A.; Mol, A.P.J.; Tatenhove, van J.P.M.

    2010-01-01

    The article explores the governance structures that would be needed to cope with extreme and unpredictable climate change. The impacts on the Netherlands of a Gulf Stream collapse in the Northern Atlantic are taken as a case. This hypothetical situation of serious risks and high uncertainties

  12. Climate selection and development of climate indicators

    Energy Technology Data Exchange (ETDEWEB)

    Bowen, W.M.; Moreno, S.; Olsen, A.R.

    1982-09-01

    A climate analysis procedure for selecting climate locations which would represent the variation in climate conditions throughout the United States is documented. Separate energy analysis projects for three building categories were to use the results of the climate location project. The categories are: commercial buildings (including multifamily residences), single family residences, and mobile homes. The overall objectives, approach, and method used for all three categories are presented, then the specific application of the general method to each building category is discussed. Climate selection results, conclusions, recommendations, and limits for each building category are presented within the description of the application of the method for that category. (LEW)

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

    Science.gov (United States)

    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. Climatic indicators of desertification in Basilicata, Italy

    Directory of Open Access Journals (Sweden)

    2005-01-01

    Full Text Available Climate changes such as the increase, in intensity and frequency, of extreme phenomena - hurricanes, thunder storms, flooding, drought -, of temperature and of biodiversity loss can influence land morphogenetic processes and prime a severe decreasing of natural resources such as the desertification. Desertification, that is the progressive loss of large areas of globe removed from human activities, is one of the most urgent problems in the last decades and is a phenomenon occurring on the most part of Mediterranean countries, such as Italy and in particular its Southern area. The most interested areas and regions are: Sicily, Sardinia, Pelage island, Pantelleria, Egadi island, Ustica, Calabria and Basilicata. The National Action Plane against Desertification (in Italian PAN calls for synergy between resources and expertises of Basilicata Regional Office, APAT, ARPAB and research organizations for monitoring the Desertification Status Indicators. ARPAB monitoring Section developed a project to monitor indices and indicators. In this project, we focused on climatology, that is the study of climate and its variability; in particular we characterized rainfalls regimes, homogeneous rainfall areas and extreme rainfall events. Until now, this study produced historical trends of temperature and rainfall, and maps of indicators of desertification, in particular annual maps of aridity, and monthly and quarterly maps of drought. The analysis of the thematic maps of precipitation, drought and aridity gave us the possibility of evaluating the Region Basilicata tendency to the desertification phenomenon and, in particular, by considering the climatic and morphological variability. Concerning the observation periods (80 years of precipitations, 10 years of aridity, last 3 years of drought data the region susceptibility to drought and aridity is higher in the NW and SE areas as compared to the Apennine areas on the NE-SW direction.

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

    Science.gov (United States)

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

    2014-02-01

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

  16. Can a regional climate model reproduce observed extreme temperatures?

    Directory of Open Access Journals (Sweden)

    Peter F. Craigmile

    2013-10-01

    Full Text Available Using output from a regional Swedish climate model and observations from the Swedish synoptic observational network, we compare seasonal minimum temperatures from model output and observations using marginal extreme value modeling techniques. We make seasonal comparisons using generalized extreme value models and empirically estimate the shift in the distribution as a function of the regional climate model values, using the Doksum shift function. Spatial and temporal comparisons over south central Sweden are made by building hierarchical Bayesian generalized extreme value models for the observed minima and regional climate model output. Generally speaking the regional model is surprisingly well calibrated for minimum temperatures. We do detect a problem in the regional model to produce minimum temperatures close to 0◦C. The seasonal spatial effects are quite similar between data and regional model. The observations indicate relatively strong warming, especially in the northern region. This signal is present in the regional model, but is not as strong.

  17. Recent trends of extreme temperature indices for the Iberian Peninsula

    Science.gov (United States)

    Fonseca, D.; Carvalho, M. J.; Marta-Almeida, M.; Melo-Gonçalves, P.; Rocha, A.

    2016-08-01

    Climate change and extreme climate events have a significant impact on societies and ecosystems. As a result, climate change projections, especially related with extreme temperature events, have gained increasing importance due to their impacts on the well-being of the population and ecosystems. However, most studies in the field are based on coarse global climate models (GCMs). In this study, we perform a high resolution downscaling simulation to evaluate recent trends of extreme temperature indices. The model used was Weather Research and Forecast (WRF) forced by MPI-ESM-LR, which has been shown to be one of the more robust models to simulate European climate. The domain used in the simulations includes the Iberian Peninsula and the simulation covers the 1986-2005 period (i.e. recent past). In order to study extreme temperature events, trends were computed using the Theil-Sen method for a set of temperature indexes defined by the Expert Team on Climate Change Detection and Indices (ETCCDI). For this, daily values of minimum and maximum temperatures were used. The trends of the indexes were computed for annual and seasonal values and the Mann-Kendall Trend test was used to evaluate their statistical significance. In order to validate the results, a second simulation, in which WRF was forced by ERA-Interim, was performed. The results suggest an increase in the number of warm days and warm nights, especially during summer and negative trends for cold nights and cold days for the summer and spring. For the winter, contrary to the expected, the results suggest an increase in cold days and cold nights (warming hiatus). This behavior is supported by the WRF simulation forced by ERA-Interim for the autumn days, pointing to an extension of the warming hiatus phenomenon to the remaining seasons. These results should be used with caution since the period used to calculate the trends may not be long enough for this purpose. However, the general sign of trends are similar for

  18. Extreme weather and climate in Europe

    OpenAIRE

    van der Linden, Paul; Dempsey, Peter; Dunn, Robert; Caesar, John; KURNIK Blaz; Dankers, Rutger; Jol, Andre; Kunz, Michael; van Lanen, Henny; Benestad, Rasmus; Parry, Simon; Hilden, Mikael; Marx, Andreas; Mysiak, Jaroslav; Kendon, Lizzie

    2015-01-01

    This report describes the current scientific knowledge of extreme weather and climate events in Europe for the following variables: temperature, precipitation, hail, and drought (with the following types of drought: meteorological, hydrological and soil moisture). The content summarises key literature drawn from peer reviewed journals and other sources (business and government reports), and builds upon the synthesised results presented in international assessments such as IPCC reports. It des...

  19. Climate change and extreme events in weather

    Digital Repository Service at National Institute of Oceanography (India)

    RameshKumar, M.R.

    monsoon and b) tropical cyclones. Basically the climate of India is domi- nated by the south west monsoon season which accounts for about 75% of the annual rainfall. The extreme weather events occur over India are: Floods, Droughts, Tropical Cyclones..., Heat Waves and Cold Waves, Storms Surges, Hail Storms, Thunderstorms, Dust Storms. Floods, droughts and tropical cyclones have specific significance a far as India is concerned. Floods and droughts are the two sides of the weather phenomena...

  20. Recent Changes of Some Observed Climate Extreme Events in Kano

    Directory of Open Access Journals (Sweden)

    Imole Ezekiel Gbode

    2015-01-01

    Full Text Available Observed rainfall and temperature data for the period 1960–2007 were used to examine recent changes of extreme climate over Kano, located in the Sahelian region of Nigeria. The RClimDex software package was employed to generate nine important climate indices as defined by the Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI. For the entire period, the results show a warming trend, an increased number of cool nights, more warm days, and a strong increase in the number of warm spells. The rainfall indices show a slight increase in annual total rainfall, a decrease in the maximum number of consecutive wet days, and a significant increase in the number of extremely wet days. Such changes in climate may result in an increasing demand for domestic energy for cooling and a higher evaporation rate from water bodies and irrigated crop. These findings may give some guidance to politicians and planners in how to best cope with these extreme weather and climate events.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    Science.gov (United States)

    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

  4. Detecting Extreme Events in Gridded Climate Data

    Energy Technology Data Exchange (ETDEWEB)

    Ramachandra, Bharathkumar [North Carolina State University (NCSU), Raleigh; Gadiraju, Krishna [North Carolina State University (NCSU), Raleigh; Vatsavai, Raju [North Carolina State University (NCSU), Raleigh; Kaiser, Dale Patrick [ORNL; Karnowski, Thomas Paul [ORNL

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Gang [Cornell Univ., Ithaca, NY (United States)

    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.

  6. Improving the Accuracy of Estimation of Climate Extremes

    Science.gov (United States)

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

    2010-12-01

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

  7. 北京气候变暖与主要极端气温指数的归因分析%AN ATTRIBUTION ANALYSIS BETWEEN THE CLIMATE WARMING AND EXTREME TEMPERATURE INDICES IN BEIJING IN THE PAST 49 YEARS

    Institute of Scientific and Technical Information of China (English)

    郑祚芳; 张秀丽; 高华

    2012-01-01

    在对资料进行均一化处理的基础上,分析了北京1960-2008年气候变暖及主要极端气温指数的统计特征,并应用格兰杰检验法对其进行归因分析.结果表明:(1)近49 a来北京年平均气温增速约为0.39℃/(10 a),气候增暖具有明显的非对称性.(2)霜冻指数和气温年较差呈下降趋势,降幅为3.9 d/(10 a)和0.8℃/(10 a).生长季指数、暖夜指数及热浪指数则呈上升趋势,增幅平均达3.0 d/(10 a)、0.75%/(10 a)和1.5d/(10 a).(3)北京年平均气温是霜冻指数、生长季指数及暖夜指数发生变化的格兰杰原因.虽然年平均气温与热浪指数在不同滞后期均具强相关性,但是检验表明它们之间并无显著的因果关系,很可能是由于某种原因导致的一种统计上的伪相关现象.%Using the homogenized temperature data series during 1960-2008, the characteristics of climate warming and variation of extreme temperature indices in Beijing are analyzed. By introducing the Granger causality detection algorithm, the relationship between climate warming and extreme temperature indices is studied. The results have the following indication. (1) The increase rate of annual mean temperature is 0.39 ℃/(10 a), and the mean maximum and minimum temperatures change asymmetrically. (2) The decreasing rates of frost days (FD) and extreme temperature range (ETR) are 3.9 d/(10 a) and 0.8 t/(10 a), respecitively. The frequency of growing season length (GSL), warm nights (WN90) and heat wave duration index (HWDI) increase evidently with year, with their increasing rates at 3.0 d/(10 a), 0.75%/(10 a) and 1.5 d/(10 a), respecitively. (3) The Granger causality detection results show that the climate warming is the cause of the variation of FD, GSL and WN90. The existence of causality is very valuable for the forecast of extreme temperature events.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    NARCIS (Netherlands)

    Shongwe, M.E.

    2010-01-01

    Climate extremes are rarely occurring natural phenomena in the climate system. They often pose one of the greatest environmental threats to human and natural systems. Statistical methods are commonly used to investigate characteristics of climate extremes. The fitted statistical properties are often

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

    Science.gov (United States)

    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. Extreme Precipitation and Runoff under Changing Climate in Southern Maine

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Eugene [Argonne National Lab. (ANL), Argonne, IL (United States); Jared, Alissa [Argonne National Lab. (ANL), Argonne, IL (United States); Mahat, Vinod [Argonne National Lab. (ANL), Argonne, IL (United States); Picel, Mark [Argonne National Lab. (ANL), Argonne, IL (United States); Verner, Duane [Argonne National Lab. (ANL), Argonne, IL (United States); Wall, Thomas [Argonne National Lab. (ANL), Argonne, IL (United States); Moges, Edom M. [Washington State Univ., Pullman, WA (United States); Demissie, Yonas K. [Washington State Univ., Pullman, WA (United States); Pierce, Julia [Argonne National Lab. (ANL), Argonne, IL (United States)

    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.

  13. Inter-comparison of statistical downscaling methods for projection of extreme flow indices across Europe

    DEFF Research Database (Denmark)

    Hundecha, Yeshewatesfa; Sunyer Pinya, Maria Antonia; Lawrence, Deborah;

    2016-01-01

    flow indices in most of the catchments. The catchments where the extremes are expected to increase have a rainfall-dominated flood regime. In these catchments, the downscaling methods also project an increase in the extreme precipitation in the seasons when the extreme flows occur. In catchments where...... the flooding is mainly caused by spring/summer snowmelt, the downscaling methods project a decrease in the extreme flows in three of the four catchments considered. A major portion of the variability in the projected changes in the extreme flow indices is attributable to the variability of the climate model......The effect of methods of statistical downscaling of daily precipitation on changes in extreme flow indices under a plausible future climate change scenario was investigated in 11 catchments selected from 9 countries in different parts of Europe. The catchments vary from 67 to 6171km2 in size...

  14. Inter-comparison of statistical downscaling methods for projection of extreme flow indices across Europe

    Science.gov (United States)

    Hundecha, Yeshewatesfa; Sunyer, Maria A.; Lawrence, Deborah; Madsen, Henrik; Willems, Patrick; Bürger, Gerd; Kriaučiūnienė, Jurate; Loukas, Athanasios; Martinkova, Marta; Osuch, Marzena; Vasiliades, Lampros; von Christierson, Birgitte; Vormoor, Klaus; Yücel, Ismail

    2016-10-01

    The effect of methods of statistical downscaling of daily precipitation on changes in extreme flow indices under a plausible future climate change scenario was investigated in 11 catchments selected from 9 countries in different parts of Europe. The catchments vary from 67 to 6171 km2 in size and cover different climate zones. 15 regional climate model outputs and 8 different statistical downscaling methods, which are broadly categorized as change factor and bias correction based methods, were used for the comparative analyses. Different hydrological models were implemented in different catchments to simulate daily runoff. A set of flood indices were derived from daily flows and their changes have been evaluated by comparing their values derived from simulations corresponding to the current and future climate. Most of the implemented downscaling methods project an increase in the extreme flow indices in most of the catchments. The catchments where the extremes are expected to increase have a rainfall-dominated flood regime. In these catchments, the downscaling methods also project an increase in the extreme precipitation in the seasons when the extreme flows occur. In catchments where the flooding is mainly caused by spring/summer snowmelt, the downscaling methods project a decrease in the extreme flows in three of the four catchments considered. A major portion of the variability in the projected changes in the extreme flow indices is attributable to the variability of the climate model ensemble, although the statistical downscaling methods contribute 35-60% of the total variance.

  15. webXTREME: R-based web tool for calculating agroclimatic indices of extreme events

    NARCIS (Netherlands)

    Klein, Tommy; Samourkasidis, Argyrios; Athanasiadis, I.N.; Bellocchi, Gianni; Calanca, Pierluigi

    2017-01-01

    We document the release of webXTREME, a new online tool for the evaluation of indices of climatic extremes (extreme temperatures and aridity) having impact on agricultural production. The tool is globally available and can be operated with either observed weather data or time series representing

  16. Methodology for qualitative uncertainty assessment of climate impact indicators

    Science.gov (United States)

    Otto, Juliane; Keup-Thiel, Elke; Rechid, Diana; Hänsler, Andreas; Pfeifer, Susanne; Roth, Ellinor; Jacob, Daniela

    2016-04-01

    The FP7 project "Climate Information Portal for Copernicus" (CLIPC) is developing an integrated platform of climate data services to provide a single point of access for authoritative scientific information on climate change and climate change impacts. In this project, the Climate Service Center Germany (GERICS) has been in charge of the development of a methodology on how to assess the uncertainties related to climate impact indicators. Existing climate data portals mainly treat the uncertainties in two ways: Either they provide generic guidance and/or express with statistical measures the quantifiable fraction of the uncertainty. However, none of the climate data portals give the users a qualitative guidance how confident they can be in the validity of the displayed data. The need for such guidance was identified in CLIPC user consultations. Therefore, we aim to provide an uncertainty assessment that provides the users with climate impact indicator-specific guidance on the degree to which they can trust the outcome. We will present an approach that provides information on the importance of different sources of uncertainties associated with a specific climate impact indicator and how these sources affect the overall 'degree of confidence' of this respective indicator. To meet users requirements in the effective communication of uncertainties, their feedback has been involved during the development process of the methodology. Assessing and visualising the quantitative component of uncertainty is part of the qualitative guidance. As visual analysis method, we apply the Climate Signal Maps (Pfeifer et al. 2015), which highlight only those areas with robust climate change signals. Here, robustness is defined as a combination of model agreement and the significance of the individual model projections. Reference Pfeifer, S., Bülow, K., Gobiet, A., Hänsler, A., Mudelsee, M., Otto, J., Rechid, D., Teichmann, C. and Jacob, D.: Robustness of Ensemble Climate Projections

  17. Rainfall Variability and the Recent Climate Extremes in Nigeria ...

    African Journals Online (AJOL)

    Weather patterns affecting the country are driven by the northward and southward ... Climatic and statistical analyses were employed to investigate two extreme ... of Nigeria have suffered from inter-annual to seasonal climatic variabilities and ...

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

    Science.gov (United States)

    Espírito Santo, Fátima; de Lima, Isabel P.

    2014-05-01

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

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  1. Influence of Climate Oscillations on Extreme Precipitation in Texas

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  3. Response of Groundwater to Climate Change under Extreme Climate Conditions in North China Plain

    Institute of Scientific and Technical Information of China (English)

    Ying Zhang; Jincui Wang; Jihong Jing; Jichao Sun

    2014-01-01

    The North China Plain (NCP) is one of the water shortage areas of China. Lack of water resources restricted the economic and social development of North China area and resulted in deterio-ration of ecosystem and natural environment. Influenced by the climate change and human activities, the water circulation of NCP was largely changed and the crisis of water resources was aggravated. Therefore, it is important to study the features of the extreme climate and the response mechanism of groundwater to climate change. We analyzed the trend of climate change and extreme climate features in the past 60 years based on the monitoring data of meteorological stations. And then the response characteristics of groundwater to climate change were discussed. The average temperature of NCP was in an obviously upward trend. The overall precipitation variation was in a downward trend. The cli-mate change in this area showed a warming-drying trend. The intensity of extreme precipitation dis-played a trend of declining and then increasing from north to south as well as declining from eastern coastal plain to the piedmont plain. Grey correlation degree analysis indicated that groundwater depth had a close relationship with precipitation and human activities in NCP. The response of groundwater level to precipitation differed from the piedmont alluvial-pluvial plain to the coastal plain. The response was more obvious in the coastal plain than the piedmont alluvial-pluvial plain and the middle plain. The precipitation influenced the groundwater depth both directly and indirectly. Under the condition of extreme precipitation, the impact would aggravate, in the forms of rapid or lag raise of groundwater levels.

  4. Tendências de índices de extremos climáticos para a região de Manaus-AM Trends of extreme climatic indices for Manaus - AM region

    Directory of Open Access Journals (Sweden)

    Carlos Antonio Costa dos Santos

    2012-09-01

    Full Text Available Foram estudadas tendências nos índices de extremos climáticos baseados em dados de precipitação para três estações localizadas em Manaus e na região circunvizinha para o período de 1971-2007. Baseado nos resultados obtidos pode ser observado que houve aumento da precipitação total anual sobre a região estudada. A estação localizada na zona urbana de Manaus (INMET teve aumento, com significância estatística, dos eventos de precipitação iguais ou superiores a 50 mm (R50mm, na precipitação máxima acumulada em cinco dias consecutivos (Rx5day e nos dias úmidos (R95p, indicando que Manaus poderá sofrer com o aumento das chuvas extremas. Aumento das anomalias positivas de TSM no Oceano Pacífico Equatorial leva a um aumento dos dias consecutivos secos e diminuição dos eventos extremos de chuva e da precipitação total sobre a bacia amazônica. As anomalias positivas de TSM no Oceano Atlântico Sul induz o deslocamento da ZCIT mais ao sul do Equador levando a um aumento da precipitação sobre a região de Manaus. Os resultados obtidos aqui têm potencial para possíveis previsões das características da precipitação em Manaus.Trends in the extreme climate indices based on precipitation data at three stations in and around the city of Manaus for the period 1971-2007 are studied. Based on the results obtained it can be observed that there was an increase of the annual total precipitation in the area studied. At the station located in the city of Manaus (INMET, the frequency of precipitation events with 50 mm (R50mm or more, the amount precipitation in five consecutive days (Rx5day and the number of wet days (R95p, showed an increase, with statistical significance, indicating that Manaus may suffer with the increase of the extreme rainfall events. An increase in the positive SST anomalies in the Equatorial Pacific Ocean induce an increase of the consecutive dry days and decrease of the extreme rainfall events and

  5. Public perceptions of climate change and extreme weather events

    Science.gov (United States)

    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

  6. Characteristics of extreme climate sequences over Korea using a regional climate change scenario

    Energy Technology Data Exchange (ETDEWEB)

    Eun-Soon, I.; Kwon, W.T. [KMA, Seoul (Korea). Climate Research Lab.

    2007-07-01

    The authors investigate the characteristics and potential future change of extreme climate phenomena based on daily statistical properties. To assess the fine-scale climate change projection over Korea, an ECHO-G B2 scenario simulation has been dynamically downscaled by using the RegCM3 nesting system. Two sets of multidecadal simulations are performed for the present day (1971.2000) and future climate (2021.2050). They analyze four categories of weather spells in terms of the sequences of dry/wet and frost/hot days from the nested domain simulation of 20 km grid spacing. In the validation of the reference scenario, the model shows a reasonable performance of reproducing both observed climatological and distinct characteristics of each spell. Regarding the projected extreme climate events, the results indicate not only a significant change in frequency and intensity, but also substantial change in the fine scale detail of the regional distribution of temperature-based as well as precipitation-based extreme events. A substantial increase of hot spells is found along with increasing of maximum temperature. Longer-period frost spells are projected to decrease, whereas relatively short-period frost spells are likely to increase due to breaks of long spells by greenhouse warming. Wet spells of long periods tend to be more frequent, showing a distinct variation across regions. A recent study using the outputs of the IPCC AR4 coupled climate models also reports a significant increase of summer monsoon precipitation and a possible increase in the length of the summer monsoon period over East Asia in particular over Korea (Kripalani et al. 2006). Hence it is important to quantify the influence of greenhouse-gas-induced climate change upon the frequency and intensity of extreme events at regional scale.

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

    Science.gov (United States)

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

    2010-09-01

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

  8. Extreme Risk In Resource Indices And The Generalized Logistic Distribution

    National Research Council Canada - National Science Library

    Chun-Kai Huang; Venelle Pather; Jahvaid Hammujuddy; Knowledge Chinhamu

    2017-01-01

    .... In this article, we compare performances of classical extreme value models against the recently suggested generalized logistic distribution, for estimating value-at-risk and expected shortfall in resource indices...

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

    Directory of Open Access Journals (Sweden)

    Annette Leingärtner

    Full Text Available 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.

  10. Climate change impacts on hydrological extremes in Central Europe

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2016-04-01

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

  12. Mekong River flow and hydrological extremes under climate change

    NARCIS (Netherlands)

    Hoang, P.L.; Lauri, P.; Kummu, M.; Koponen, J.; Vliet, van M.T.H.; Supit, I.; Leemans, H.B.J.; Kabat, P.; Ludwig, F.

    2016-01-01

    Climate change poses critical threats to water related safety and sustainability in the Mekong River basin. Hydrological impact signals derived from CMIP3 climate change scenarios, however, are highly uncertain and largely ignore hydrological extremes. This paper provides one of the first hydrologic

  13. Directional analysis of extreme winds under mixed climate conditions

    CSIR Research Space (South Africa)

    Kruger, A

    2013-07-01

    Full Text Available -1 European-African Conference on Wind Engineering 2013, Robinson College, Cambridge, July 2013 Directional Analysis of Extreme Winds under Mixed Climate Conditions *Andries Kruger1, Adam Goliger2 and Johan Retief3 1Climate Service, South African...

  14. Assessment of indices of temperature extremes simulated by multiple CMIP5 models over China

    Science.gov (United States)

    Dong, Siyan; Xu, Ying; Zhou, Botao; Shi, Ying

    2015-08-01

    Given that climate extremes in China might have serious regional and global consequences, an increasing number of studies are examining temperature extremes in China using the Coupled Model Intercomparison Project Phase 5 (CMIP5) models. This paper investigates recent changes in temperature extremes in China using 25 state-of-the-art global climate models participating in CMIP5. Thirteen indices that represent extreme temperature events were chosen and derived by daily maximum and minimum temperatures, including those representing the intensity (absolute indices and threshold indices), duration (duration indices), and frequency (percentile indices) of extreme temperature. The overall performance of each model is summarized by a "portrait" diagram based on relative root-mean-square error, which is the RMSE relative to the median RMSE of all models, revealing the multi-model ensemble simulation to be better than individual model for most indices. Compared with observations, the models are able to capture the main features of the spatial distribution of extreme temperature during 1986-2005. Overall, the CMIP5 models are able to depict the observed indices well, and the spatial structure of the ensemble result is better for threshold indices than frequency indices. The spread amongst the CMIP5 models in different subregions for intensity indices is small and the median CMIP5 is close to observations; however, for the duration and frequency indices there can be wide disagreement regarding the change between models and observations in some regions. The model ensemble also performs well in reproducing the observational trend of temperature extremes. All absolute indices increase over China during 1961-2005.

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

    Science.gov (United States)

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

    2007-12-01

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

  16. Physical, Ecological, and Societal Indicators for the National Climate Assessment

    Science.gov (United States)

    Kenney, Melissa A.; Chen, Robert; Baptista, Sandra R.; Quattrochi, Dale; O'Brien, Sheila

    2011-01-01

    The National Climate Assessment (NCA) is being conducted under the auspices of the U.S. Global Change Research Program (USGCRP), pursuant to the Global Change Research Act of 1990, Section 106, which requires a report to Congress every 4 years. The current NCA (http://globalchange.gov/what-we-do/assessment/) differs in multiple ways from previous U.S. climate assessment efforts, being: (1) more focused on supporting the Nation s activities in adaptation and mitigation and on evaluating the current state of scientific knowledge relative to climate impacts and trends; (2) a long-term, consistent process for evaluation of climate risks and opportunities and providing information to support decision-making processes within regions and sectors; and (3) establishing a permanent assessment capacity both inside and outside of the federal government. As a part of ongoing, long-term assessment activities, the NCA intends to develop an integrated strategic framework and deploy climate-relevant physical, ecological, and societal indicators. The NCA indicators framework is underdevelopment by the NCA Development and Advisory Committee Indicators Working Group and are envisioned as a relatively small number of policy-relevant integrated indicators designed to provide a consistent, objective, and transparent overview of major variations in climate impacts, vulnerabilities, adaptation, and mitigation activities across sectors, regions, and timeframes. The potential questions that could be addressed by these indicators include: How do we know that there is a changing climate and how is it expected to change in the future? Are important climate impacts and opportunities occurring or predicted to occur in the future? Are we adapting successfully? What are the vulnerabilities and resiliencies given a changing climate? Are we preparing adequately for extreme events? It is not expected that the NCA societal indicators would be linked directly to a single decision or portfolio of

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

    Science.gov (United States)

    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

  18. Uncertainties in extreme precipitation under climate change conditions

    DEFF Research Database (Denmark)

    Sunyer Pinya, Maria Antonia

    of adaptation strategies, but these changes are subject to uncertainties. The focus of this PhD thesis is the quantification of uncertainties in changes in extreme precipitation. It addresses two of the main sources of uncertainty in climate change impact studies: regional climate models (RCMs) and statistical...... by extreme precipitation pose a threat to human life and cause high economic losses for society. Thus, strategies to adapt to changes in extreme precipitation are currently being developed and established worldwide. Information on the expected changes in extreme precipitation is required for the development...... downscaling methods (SDMs). RCMs provide information on climate change at the regional scale. SDMs are used to bias-correct and downscale the outputs of the RCMs to the local scale of interest in adaptation strategies. In the first part of the study, a multi-model ensemble of RCMs from the European ENSEMBLES...

  19. Climatic forecast: down-scaling and extremes; La prevision climatique: regionalisation et extremes

    Energy Technology Data Exchange (ETDEWEB)

    Deque, M. [Meteo France, Centre National de Recherches Meteorologiques (CNRM), 31 - Toulouse (France); Li, L. [Laboratoire de Meteorologie Dynamique, Institut Pierre-Simon Laplace, Ecole Polytechnique, 91 - Palaiseau (France)

    2007-05-15

    There is a strong demand for specifying the future climate at local scale and about extreme events. New methods, allowing a better output from the climate models, are currently being developed and French laboratories involved in the Escrime project are actively participating. (authors)

  20. Mekong River flow and hydrological extremes under climate change

    Directory of Open Access Journals (Sweden)

    L. P. Hoang

    2015-11-01

    Full Text Available Climate change poses critical threats to water related safety and sustainability in the Mekong River basin. Hydrological impact signals derived from CMIP3 climate change scenarios, however, are highly uncertain and largely ignore hydrological extremes. This paper provides one of the first hydrological impact assessments using the most recent CMIP5 climate change scenarios. Furthermore, we model and analyse changes in river flow regimes and hydrological extremes (i.e. high flow and low flow conditions. Similar to earlier CMIP3-based assessments, the hydrological cycle also intensifies in the CMIP5 climate change scenarios. The scenarios 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. 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 risk in the basin. The implications of climate change induced hydrological changes are critical and thus require special attention in climate change adaptation and disaster-risk reduction.

  1. Mekong River flow and hydrological extremes under climate change

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  6. Observed variability and trends in extreme rainfall indices and Peaks-Over-Threshold series

    Directory of Open Access Journals (Sweden)

    H. Saidi

    2013-05-01

    Full Text Available Intensification of heavy precipitation as discussed in climate change studies has become a public concern, but it has not yet been examined well with observed data, particularly with data at short temporal scale like hourly and sub-hourly data. In this research we digitalized sub-hourly precipitation recorded at the stations of Vercelli (since 1927, Bra (since 1933, Lombriasco (since 1939 and Pallanza (since 1950 in order to investigate historical change in extreme short precipitations. These stations are located in the northwest of Italy. Besides seasonal and yearly maximum of precipitation we adopted two indices of extreme rainfall: the number of events above an extreme threshold (extreme frequency, and the average intensity of rainfall from extreme events (extreme intensity. The results showed a statistically significant increase of the extreme frequency index and spring maximum precipitation for Bra and Lombriasco. The extreme intensity index presented by the means of events above 95th percentile is decreasing for Bra regarding hourly precipitation and increasing for Lombriasco regarding 20 min extreme events. In Pallanza, we noticed only a positive trend of the extreme frequency and extreme intensity indices of events with duration of 30 min. For the analyses presented in this paper, a peak-over-threshold approach was chosen. Investigation presented showed that extreme events have risen in the last 20 yr only for short duration. Here it cannot be said that in our study area recent sub-hourly and hourly precipitation have become unprecedently strong or frequent for all the stations and for all the extreme events duration.

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

    Science.gov (United States)

    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

  8. Analysis of Potential Future Climate and Climate Extremes in the Brazos Headwaters Basin, Texas

    Directory of Open Access Journals (Sweden)

    Ripendra Awal

    2016-12-01

    Full Text Available Texas’ fast-growing economy and population, coupled with cycles of droughts due to climate change, are creating an insatiable demand for water and an increasing need to understand the potential impacts of future climates and climate extremes on the state’s water resources. The objective of this study was to determine potential future climates and climate extremes; and to assess spatial and temporal changes in precipitation (Prec, and minimum and maximum temperature (Tmin and Tmax, respectively, in the Brazos Headwaters Basin under three greenhouse gas emissions scenarios (A2, A1B, and B1 for three future periods: 2020s (2011–2030, 2055s (2046–2065, and 2090s (2080–2099. Daily gridded climate data obtained from Climate Forecast System Reanalysis (CFSR were used to downscale outputs from 15 General Circulation Models (GCMs using the Long Ashton Research Station–Weather Generator (LARS-WG model. Results indicate that basin average Tmin and Tmax will increase; however, annual precipitation will decrease for all periods. Annual precipitation will decrease by up to 5.2% and 6.8% in the 2055s and 2090s, respectively. However, in some locations in the basin, up to a 14% decrease in precipitation is projected in the 2090s under the A2 (high emissions scenario. Overall, the northwestern and southern part of the Brazos Headwaters Basin will experience greater decreases in precipitation. Moreover, precipitation indices of the number of wet days (prec ≥ 5 mm and heavy precipitation days (prec ≥ 10 mm are projected to slightly decrease for all future periods. On the other hand, Tmin and Tmax will increase by 2 and 3 °C on average in the 2055s and 2090s, respectively. Mostly, projected increases in Tmin and Tmax will be in the upper range in the southern and southeastern part of the basin. Temperature indices of frost (Tmin < 0 °C and ice days (Tmax < 0 °C are projected to decrease, while tropical nights (Tmin > 20 °C and summer days (Tmax

  9. Perspectives on Extremes as a Climate Scientist and Farmer

    Science.gov (United States)

    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.

  10. TECA: A Parallel Toolkit for Extreme Climate Analysis

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

  12. Mekong River flow and hydrological extremes under climate change

    OpenAIRE

    Hoang, L.P.; H. Lauri; M. Kummu; Koponen, J.; van Vliet, M. T. H.; I. Supit; Leemans, R.; Kabat, P.; Ludwig, F.

    2016-01-01

    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 hydrologica...

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  16. Investigating uncertainties in global gridded datasets of climate extremes

    Directory of Open Access Journals (Sweden)

    R. J. H. Dunn

    2014-05-01

    Full Text Available We assess the effects of different methodological choices made during the construction of gridded datasets of climate extremes, focusing primarily on HadEX2. Using global timeseries of the indices and their coverage, as well as uncertainty maps, we show that the choices which have the greatest effect are those relating to the station network used or which drastically change the values for individual grid boxes. The latter are most affected by the number of stations required in or around a grid box and the gridding method used. Most parametric changes have a small impact, on global and on grid box scales, whereas structural changes to the methods or input station networks may have large effects. On grid box scales, trends in temperature indices are very robust to most choices, especially in areas which have high station density (e.g. North America, Europe and Asia. Precipitation trends, being less spatially coherent, can be more susceptible to methodological changes, but are still clear in regions of high station density. Regional trends from all indices derived from areas with few stations should be treated with care. On a global scale, the linear trends over 1951–2010 from almost all choices fall within the statistical range of trends from HadEX2. This demonstrates the robust nature of HadEX2 and related datasets to choices in the creation method.

  17. Assessing changes in extreme precipitation over Xinjiang using regional climate model of PRECIS

    Institute of Scientific and Technical Information of China (English)

    YanWei Zhang; QuanSheng Ge; FengQing Jiang; JingYun Zheng; WenShou Wei

    2015-01-01

    In this paper, an analysis, with the simulation of PRECIS (Providing Regional Climate for Impact Studies), was made for future precipitation extremes, under SRES (Special Report on Emission Scenarios) A2 and B2 in IPCC (Intergovernmental Panel on Climate Change) AR4. The precipitation extremes were calculated and analyzed by ETCCDI (Climate Change Detection and Indices). The results show that: (1) In Present Scenario (1961–1900), PRECIS could capture the spatial pattern of precipitation in Xinjiang. (2) The simulated annual precipitation and seasonal precipitation in Xinjiang had a significantly positive trend and its variability had been deeply impacted by terrain. There was a strong association between increasing trend and the extreme precipitation's increase in frequency and intensity during 1961–2008. Under SRES A2 and B2, extreme precipitation indicated an increasing tendency at the end of the 21st century. The extreme summer pre-cipitation increased prominently in a year. (3) PRECIS's simulation under SRES A2 and B2 indicated increased frequency of heavy precipitation events and also enhancement in their intensity towards the end of the 21st century. Both A2 and B2 scenarios show similar patterns of projected changes in precipitation extremes towards the end of the 21st century. However, the magnitude of changes in B2 scenario was on the lower side. In case of extreme precipitation, variation between models can exceed both internal variability and variability of different SRES.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  20. Review of trend analysis and climate change projections of extreme precipitation and floods in Europe

    Science.gov (United States)

    Madsen, H.; Lawrence, D.; Lang, M.; Martinkova, M.; Kjeldsen, T. R.

    2014-11-01

    This paper presents a review of trend analysis of extreme precipitation and hydrological floods in Europe based on observations and future climate projections. The review summaries methods and methodologies applied and key findings from a large number of studies. Reported analyses of observed extreme precipitation and flood records show that there is some evidence of a general increase in extreme precipitation, whereas there are no clear indications of significant trends at large-scale regional or national level of extreme streamflow. Several studies from regions dominated by snowmelt-induced peak flows report decreases in extreme streamflow and earlier spring snowmelt peak flows, likely caused by increasing temperature. The review of likely future changes based on climate projections indicates a general increase in extreme precipitation under a future climate, which is consistent with the observed trends. Hydrological projections of peak flows show large impacts in many areas with both positive and negative changes. A general decrease in flood magnitude and earlier spring floods are projected for catchments with snowmelt-dominated peak flows, which is consistent with the observed trends. Finally, existing guidelines in Europe on design flood and design rainfall estimation are reviewed. The review shows that only few countries have developed guidelines that incorporate a consideration of climate change impacts.

  1. Expected impacts of climate change on extreme climate events; Impacts du changement climatique sur les evenements climatiques extremes

    Energy Technology Data Exchange (ETDEWEB)

    Planton, S.; Deque, M.; Chauvin, F. [Meteo-France, Centre National de Recherches Meteorologiques/groupe d' Etude de l' Atmosphere Meteorologique (CNRM/GAME), 31 - Toulouse (France); Terray, L. [Centre Europeen de Recherches Avancees en Calcul Scientifique, 31 - Toulouse (France)

    2008-09-15

    An overview of the expected change of climate extremes during this century due to greenhouse gases and aerosol anthropogenic emissions is presented. The most commonly used methodologies rely on the dynamical or statistical down-scaling of climate projections, performed with coupled atmosphere-ocean general circulation models. Either of dynamical or of statistical type, down-scaling methods present strengths and weaknesses, but neither their validation on present climate conditions, nor their potential ability to project the impact of climate change on extreme event statistics allows one to give a specific advantage to one of the two types. The results synthesized in the last IPCC report and more recent studies underline a convergence for a very likely increase in heat wave episodes over land surfaces, linked to the mean warming and the increase in temperature variability. In addition, the number of days of frost should decrease and the growing season length should increase. The projected increase in heavy precipitation events appears also as very likely over most areas and also seems linked to a change in the shape of the precipitation intensity distribution. The global trends for drought duration are less consistent between models and down-scaling methodologies, due to their regional variability. The change of wind-related extremes is also regionally dependent, and associated to a poleward displacement of the mid-latitude storm tracks. The specific study of extreme events over France reveals the high sensitivity of some statistics of climate extremes at the decadal time scale as a consequence of regional climate internal variability. (authors)

  2. Generalized Extreme Value distribution parameters as dynamical indicators of Stability

    CERN Document Server

    Faranda, Davide; Turchetti, Giorgio; Vaienti, Sandro

    2011-01-01

    We introduce a new dynamical indicator of stability based on the Extreme Value statistics showing that it provides an insight on the local stability properties of dynamical systems. The indicator perform faster than other based on the iteration of the tangent map since it requires only the evolution of the original systems and, in the chaotic regions, gives further information about the information dimension of the attractor. A numerical validation of the method is presented through the analysis of the motions in a Standard map.

  3. On the importance of observational data properties when assessing regional climate model performance of extreme precipitation

    DEFF Research Database (Denmark)

    Sunyer Pinya, Maria Antonia; Sørup, Hjalte Jomo Danielsen; Christensen, Ole Bøssing

    2013-01-01

    In recent years, there has been an increase in the number of climate studies addressing changes in extreme precipitation. A common step in these studies involves the assessment of the climate model performance. This is often measured by comparing climate model output with observational data....... In the majority of such studies the characteristics and uncertainties of the observational data are neglected. This study addresses the influence of using different observational datasets to assess the climate model performance. Four different datasets covering Denmark using different gauge systems and comprising...... both networks of point measurements and gridded datasets are considered. Additionally, the influence of using different performance indices and metrics is addressed. A set of indices ranging from mean to extreme precipitation properties is calculated for all the datasets. For each of the observational...

  4. Host-parasite interactions under extreme climatic conditions

    Institute of Scientific and Technical Information of China (English)

    J. MARTINEZ; S. MERINO

    2011-01-01

    The effect that climatic changes can exert on parasitic interactions represents a multifactor problem whose results are difficult to predict. The actual impact of changes will depend on their magnitude and the physiological tolerance of affected organisms. When the change is considered extreme (I.e. Unusual weather events that are at the extremes of the historical distribution for a given area), the probability of an alteration in an organisms' homeostasis increases dramatically. However, factors determining the altered dynamics of host-parasite interactions due to an extreme change are the same as those acting in response to changes of lower magnitude. Only a deep knowledge of these factors will help to produce more accurate predictive models for the effects of extreme changes on parasitic interactions. Extreme environmental conditions may affect pathogens directly when they include free-living stages in their life-cycles and indirectly through reduced resource availability for hosts and thus reduced ability to produce efficient anti-parasite defenses, or by effects on host density affecting transmission dynamics of diseases or the frequency of intraspecific contact. What are the consequences for host-parasite interactions? Here we summarize the present knowledge on three principal factors in determining host-parasite associations; biodiversity, population density and immunocompetence. In addition, we analyzed examples of the effects of environmental alteration of anthropogenic origin on parasitic systems because the effects are analogous to that exerted by an extreme climatic change.

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

    Science.gov (United States)

    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

  6. Attribution analyses of temperature extremes using a set of 16 indices

    Directory of Open Access Journals (Sweden)

    Nikolaos Christidis

    2016-12-01

    Full Text Available Detection and attribution studies have demonstrated that anthropogenic forcings have been driving significant changes in temperature extremes since the middle of the 20th century. Moreover, new methodologies have been developed for the attribution of extreme events that assess how human influence may have changed their characteristics. Here we combine formal statistical analyses based on optimal fingerprinting to attribute observed long term changes in temperature extremes with an ensemble-based approach for event attribution. Our analyses are applied to 16 indices constructed with daily temperature data that focus on different characteristics of extremes and together build up a more complete representation of historical changes in warm and cold extremes than previous studies. For each index we compute an annual value for all years of the post-1960 period using data from observations and experiments with a coupled Earth System model for the analysis of multi-decadal changes and a high-resolution atmospheric model for event attribution. The models indicate that anthropogenic forcings have influenced almost all indices in recent decades and led to more prominent changes in the frequency of extremes. The optimal fingerprinting analyses show that for most indices the anthropogenic signal is detectable in changes during 1961–2010 both in Europe and on a quasi-global scale. The weaker natural effect, resulting mainly from volcanic eruptions, is in most cases not detectable, with the exception of large scale changes in indices linked to the frequency of cold night-time extremes. Our event analyses estimate how anthropogenic forcings alter the chances of getting new record index values in Europe and find that such extremes would be markedly rare if human influence were not accounted for, whereas in the current climate their return times range from a few years to a few decades.

  7. Trends in indices of daily temperature and precipitations extremes in Morocco

    Science.gov (United States)

    Filahi, S.; Tanarhte, M.; Mouhir, L.; El Morhit, M.; Tramblay, Y.

    2016-05-01

    The purpose of this paper is to provide a summary of Morocco's climate extreme trends during the last four decades. Indices were computed based on a daily temperature and precipitation using a consistent approach recommended by the ETCCDI. Trends in these indices were calculated at 20 stations from 1970 to 2012. Twelve indices were considered to detect trends in temperature. A large number of stations have significant trends and confirm an increase in temperature, showing increased warming during spring and summer seasons. The results also show a decrease in the number of cold days and nights and an increase in the number of warm days and nights. Increasing trends have also been found in the absolute warmest and coldest temperatures of the year. A clear increase is detected for warm nights and diurnal temperature range. Eight indices for precipitation were also analyzed, but the trends for these precipitation indices are much less significant than for temperature indices and show more mixed spatial patterns of change. Heavy precipitation events do not exhibit significant trends except at a few locations, in the north and central parts of Morocco, with a general tendency towards drier conditions. The correlation between these climate indices and the large-scale atmospheric circulations indices such as the NAO, MO, and WEMO were also analyzed. Results show a stronger relationship with these climatic indices for the precipitation indices compared to the temperature indices. The correlations are more significant in the Atlantic regions, but they remain moderate at the whole country scale.

  8. Extreme weather events in Iran under a changing climate

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    DEFF Research Database (Denmark)

    Sørensen, Carlo Sass; Knudsen, Per; Broge, Niels

    2016-01-01

    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...

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  13. Predicting climate extremes – a complex network approach

    Directory of Open Access Journals (Sweden)

    M. Weimer

    2015-10-01

    Full Text Available Regional decadal predictions have emerged in the past few years as a research field with high application potential, especially for extremes like heat and drought periods. However, up to now the prediction skill of decadal hindcasts, as evaluated with standard methods is moderate, and for extreme values even rarely investigated. In this study, we use hindcast data from a regional climate model (CCLM for 8 regions in Europe to construct time evolving climate networks and use the network correlation threshold (link strength as a predictor for heat periods. We show that the skill of the network measure to predict the low frequency dynamics of heat periods is similar to the one of the standard approach, with the potential of being even better in some regions.

  14. Statistics of Extreme Events with Application to Climate

    Science.gov (United States)

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

    Science.gov (United States)

    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. Analyses of Observed and Anticipated Changes in Extreme Climate Events in the Northwest Himalaya

    Directory of Open Access Journals (Sweden)

    Dharmaveer Singh

    2016-02-01

    Full Text Available In this study, past (1970-2005 as well as future long term (2011-2099 trends in various extreme events of temperature and precipitation have been investigated over selected hydro-meteorological stations in the Sutlej river basin. The ensembles of two Coupled Model Intercomparison Project (CMIP3 models: third generation Canadian Coupled Global Climate Model and Hadley Centre Coupled Model have been used for simulation of future daily time series of temperature (maximum and minimum and precipitation under A2 emission scenario. Large scale atmospheric variables of both models and National Centre for Environmental Prediction/National Centre for Atmospheric Research reanalysis data sets have been downscaled using statistical downscaling technique at individual stations. A total number of 25 extreme indices of temperature (14 and precipitation (11 as specified by the Expert Team of the World Meteorological Organization and Climate Variability and Predictability are derived for the past and future periods. Trends in extreme indices are detected over time using the modified Mann-Kendall test method. The stations which have shown either decrease or no change in hot extreme events (i.e., maximum TMax, warm days, warm nights, maximum TMin, tropical nights, summer days and warm spell duration indicators for 1970–2005 and increase in cold extreme events (cool days, cool nights, frost days and cold spell duration indicators are predicted to increase and decrease respectively in the future. In addition, an increase in frequency and intensity of extreme precipitation events is also predicted.

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

    Science.gov (United States)

    Kara, Fatih; Yucel, Ismail

    2015-09-01

    This study investigates the climate change impact on the changes of mean and extreme flows under current and future climate conditions in the Omerli Basin of Istanbul, Turkey. The 15 regional climate model output from the EU-ENSEMBLES project and a downscaling method based on local implications from geophysical variables were used for the comparative analyses. Automated calibration algorithm is used to optimize the parameters of Hydrologiska Byråns Vattenbalansavdel-ning (HBV) model for the study catchment using observed daily temperature and precipitation. The calibrated HBV model was implemented to simulate daily flows using precipitation and temperature data from climate models with and without downscaling method for reference (1960-1990) and scenario (2071-2100) periods. Flood indices were derived from daily flows, and their changes throughout the four seasons and year were evaluated by comparing their values derived from simulations corresponding to the current and future climate. All climate models strongly underestimate precipitation while downscaling improves their underestimation feature particularly for extreme events. Depending on precipitation input from climate models with and without downscaling the HBV also significantly underestimates daily mean and extreme flows through all seasons. However, this underestimation feature is importantly improved for all seasons especially for spring and winter through the use of downscaled inputs. Changes in extreme flows from reference to future increased for the winter and spring and decreased for the fall and summer seasons. These changes were more significant with downscaling inputs. With respect to current time, higher flow magnitudes for given return periods will be experienced in the future and hence, in the planning of the Omerli reservoir, the effective storage and water use should be sustained.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  20. The 20th century transitions in basic and extreme monsoon rainfall indices in India: Comparison of the ETCCDI indices

    Science.gov (United States)

    Panda, Dileep K.; Panigrahi, P.; Mohanty, S.; Mohanty, R. K.; Sethi, R. R.

    2016-11-01

    The mean and extreme matrices of the monsoon rainfall in India not only play an important role in depicting the global monsoon climate, but also their spatiotemporal patterns influence the socio-economic profile of a major proportion of the country's huge population. Given the reported conflicting trends at the global and national scales, the present study investigates the 20th century (1901-2004) changes in monsoon rainfall of India, particularly focusing the indices developed by the Expert Team on Climate Change Detection and Indices (ETCCDI) to facilitate a global comparison. Result of this comprehensive analysis, which includes the response of fifteen indices over two study periods (i.e., 1901-1940 and 1961-2004), indicates clear signals of change with respect to the period and region of study and the choice of the ETCCDI indices. While wet day frequency, low-to-moderate events and consecutive wet days (CWD) exhibit a prominent transition from a pre-1940 wetting to a post-1960 drying tendency over a large part of the central-north India (CNI), both the wet and dry extremes have occurred in a spatially less consistent manner during the recent decades. For consecutive dry days (CDD), the reported less clear global signals could be related to the timescale of analysis, as our sub-seasonal scale results display consistent changes compared to that of the seasonal and annual scales. The Palmer Drought Severity Index (PDSI) provides clear indications of a post-1960 non-stationarity, showing changes in the mean as well as variance. Based on the partial Mann-Kendall test (PMK), some of the identified rainfall trends during 1961-2004 are found to be influenced more by the tropical Indian Ocean sea surface temperatures than the El Niño-Southern Oscillation index. These results have important implications for formulating the water resource management strategy, particularly over the drying central and northern parts of the country.

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

    Data.gov (United States)

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

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

    DEFF Research Database (Denmark)

    Frank, Dorothea; Reichstein, Markus; Bahn, Michael

    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...... 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...

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  6. Extreme winds over Europe in the ENSEMBLES regional climate models

    Directory of Open Access Journals (Sweden)

    S. D. Outten

    2013-01-01

    Full Text Available Extreme winds cause vast amounts of damage every year and represent a major concern for numerous industries including construction, afforestation, wind energy and many others. Under a changing climate, the intensity and frequency of extreme events are expected to change, and accurate predictions of these changes will be invaluable to decision makers and society as a whole. This work examines four regional climate model downscalings over Europe from the "ENSEMBLE-based Predictions of Climate Changes and their Impacts" project (ENSEMBLES, and investigates the predicted changes in the 50 yr return wind speeds and the associated uncertainties. This is accomplished by employing the peaks-over-threshold method with the use of the Generalised Pareto Distribution. The models show that for much of Europe the 50 yr return wind is projected to change by less than 2 m s−1, while the uncertainties associated with the statistical estimates are larger than this. In keeping with previous works in this field, the largest source of uncertainty is found to be the inter-model spread, with some locations showing differences in the 50 yr return wind of over 20 m s−1 between two different downscalings.

  7. Extreme winds over Europe in the ENSEMBLES regional climate models

    Directory of Open Access Journals (Sweden)

    S. D. Outten

    2013-05-01

    Full Text Available Extreme winds cause vast amounts of damage every year and represent a major concern for numerous industries including construction, afforestation, wind energy and many others. Under a changing climate, the intensity and frequency of extreme events are expected to change, and accurate projections of these changes will be invaluable to decision makers and society as a whole. This work examines four regional climate model downscalings over Europe following the SRES A1B scenario from the "ENSEMBLE-based Predictions of Climate Changes and their Impacts" project (ENSEMBLES. It investigates the projected changes in the 50 yr return wind speeds and the associated uncertainties. This is accomplished by employing the peaks-over-threshold method with the use of the generalised Pareto distribution. The models show that, for much of Europe, the 50 yr return wind is projected to change by less than 2 m s−1, while the uncertainties associated with the statistical estimates are larger than this. In keeping with previous works in this field, the largest source of uncertainty is found to be the inter-model spread, with some locations showing differences in the 50 yr return wind of over 20 m s−1 between two different downscalings.

  8. Trends in Daily and Extreme Temperature and Precipitation Indices for the Countries of the Western Indian Ocean, 1975-2008

    Science.gov (United States)

    Aguilar, Enric; Vincent, Lucie A.

    2010-05-01

    In the framework of the project "Renforcement des Capacités des Pays de la COI dans le Domaine de l'Adaptation au Changement Climatique (ACCLIMATE)" (Comission de l'Ocean Indien, COI), a workshop on homogenization of climate data and climate change indices analysis was held in Mauritius in October 2009, using the successful format prepared by the CCl/CLIVAR/JCOMM Expert Team on Climate Change Detection and Indices. Scientists from the five countries in Western Indian Ocean brought daily climatological data from their region for a meticulous assessment of the data quality and homogeneity, and for the preparation of climate change indices which can be used for analyses of changes in climate extremes. Although the period of analysis is very short, it represents a seminal step for the compilation of longer data set and allows us to examine the evolution of climate extremes in the area during the time period identified as the decades where anthropogenic warming es larger than natural forcings. This study first presents some results of the homogeneity assessment using the software package RHtestV3 (Wang and Feng 2009) which has been developed for the detection of changepoints in climatological datasets. Indices based on homogenized daily temperatures and precipitations were also prepared for the analysis of trends at more than 50 stations across the region. The results show an increase in the percentage of warm days and warm nights over 1975-2008 while changes in extreme precipitations are not as consistent.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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).

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  14. SOILS AS INDICATORS OF CLIMATIC CHANGES

    Directory of Open Access Journals (Sweden)

    Yury Chendev

    2012-01-01

    Full Text Available A number of examples for the reaction of chernozems in the center of the East European Plain and their relation to different periodical climatic changes are examined. According to unequal-age chernozems properties, the transition from the Middle Holocene arid conditions to the Late Holocene wet conditions occurred at 4000 yr BP. Using data on changes of soil properties, the position of boundary between steppe and forest-steppe and the annual amount of precipitation at approximately 4000 yr BP were reconstructed. The change from warm-dry to cool-moist climatic phases, which occurred at the end of the XX century as a reflection of intra-age-long climatic cyclic recurrence, led to the strengthening of dehumification over the profile of automorphic chernozems and to the reduction of its content in the upper meter of the soils. The leaching of carbonates and of readily soluble salts contributed to the decrease in soil areas occupied by typical and solonetzic chernozems, and to the increase in areas occupied by leached chernozems.

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

    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

  17. Observed Trends in Indices of Daily Precipitation and Temperature Extremes in Rio de Janeiro State (brazil)

    Science.gov (United States)

    Silva, W. L.; Dereczynski, C. P.; Cavalcanti, I. F.

    2013-05-01

    One of the main concerns of contemporary society regarding prevailing climate change is related to possible changes in the frequency and intensity of extreme events. Strong heat and cold waves, droughts, severe floods, and other climatic extremes have been of great interest to researchers because of its huge impact on the environment and population, causing high monetary damages and, in some cases, loss of life. The frequency and intensity of extreme events associated with precipitation and air temperature have been increased in several regions of the planet in recent years. These changes produce serious impacts on human activities such as agriculture, health, urban planning and development and management of water resources. In this paper, we analyze the trends in indices of climatic extremes related to daily precipitation and maximum and minimum temperatures at 22 meteorological stations of the National Institute of Meteorology (INMET) in Rio de Janeiro State (Brazil) in the last 50 years. The present trends are evaluated using the software RClimdex (Canadian Meteorological Service) and are also subjected to statistical tests. Preliminary results indicate that periods of drought are getting longer in Rio de Janeiro State, except in the North/Northwest area. In "Vale do Paraíba", "Região Serrana" and "Região dos Lagos" the increase of consecutive dry days is statistically significant. However, we also detected an increase in the total annual rainfall all over the State (taxes varying from +2 to +8 mm/year), which are statistically significant at "Região Serrana". Moreover, the intensity of heavy rainfall is also growing in most of Rio de Janeiro, except in "Costa Verde". The trends of heavy rainfall indices show significant increase in the "Metropolitan Region" and in "Região Serrana", factor that increases the vulnerability to natural disasters in these areas. With respect to temperature, it is found that the frequency of hot (cold) days and nights is

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Leckebusch, G. C.; Ulbrich, U.

    2003-04-01

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

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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?

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

    Science.gov (United States)

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

    2012-12-01

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

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

    NARCIS (Netherlands)

    Swart, R.J.

    2008-01-01

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

  5. changes in indices of daily temperature and precipitation extremes ...

    African Journals Online (AJOL)

    Dr A.B.Ahmed

    classified as hotspots to climate change – such as northwest. Nigeria. This study ... poor water supply, sanitation, and overcrowding. Flooding caused ... breakage or contaminations of drinking water with severe impacts to population health.

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

    Science.gov (United States)

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

    2014-03-01

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

  7. Extreme precipitation and temperature responses to circulation patterns in current climate: statistical approaches

    NARCIS (Netherlands)

    Photiadou, C.

    2015-01-01

    Climate change is likely to influence the frequency of extreme extremes - temperature, precipitation and hydrological extremes, which implies increasing risks for flood and drought events in Europe. In current climate, European countries were often not sufficiently prepared to deal with the great so

  8. Quantification of climate change effects on extreme precipitation used for high resolution hydrologic design

    DEFF Research Database (Denmark)

    Arnbjerg-Nielsen, Karsten

    2012-01-01

    Design of urban drainage structures should include the climatic changes anticipated over the technical lifetime of the system. In Northern Europe climate changes implies increasing occurrences of extreme rainfall. Three approaches to quantify the impact of climate changes on extreme rainfall are ...

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

    Science.gov (United States)

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

    Science.gov (United States)

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

    2014-12-01

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

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

    Science.gov (United States)

    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

  12. Searching for evidence of changes in extreme rainfall indices in the Central Rift Valley of Ethiopia

    Science.gov (United States)

    Muluneh, Alemayehu; Bewket, Woldeamlak; Keesstra, Saskia; Stroosnijder, Leo

    2016-02-01

    Extreme rainfall events have serious implications for economic sectors with a close link to climate such as agriculture and food security. This holds true in the Central Rift Valley (CRV) of Ethiopia where communities rely on highly climate-sensitive rainfed subsistence farming for livelihoods. This study investigates changes in ten extreme rainfall indices over a period of 40 years (1970-2009) using 14 meteorological stations located in the CRV. The CRV consists of three landscape units: the valley floor, the escarpments, and the highlands all of which are considered in our data analysis. The Belg (March-May) and Kiremt (June-September) seasons are also considered in the analysis. The Mann-Kendall test was used to detect trends of the rainfall indices. The results indicated that at the annual time scale, more than half (57 %) of the stations showed significant trends in total wet-day precipitation (PRCPTOT) and heavy precipitation days (R10mm). Only 7-35 % of stations showed significant trends, for the other rainfall indices. Spatially, the valley floor received increasing annual rainfall while the escarpments and the highlands received decreasing annual rainfall over the last 40 years. During Belg, 50 % of the stations showed significant increases in the maximum number of consecutive dry days (CDD) in all parts of the CRV. However, most other rainfall indices during Belg showed no significant changes. During Kiremt, considering both significant and non-significant trends, almost all rainfall indices showed an increasing trend in the valley floor and a decreasing trend in the escarpment and highlands. During Belg and Kiremt, the CDD generally showed increasing tendency in the CRV.

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

    Science.gov (United States)

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

    2016-04-01

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

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

    DEFF Research Database (Denmark)

    Frank, Dorothea; Reichstein, Markus; Bahn, Michael;

    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...... 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...... 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...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ericson, Torgeir; Randers, Joergen

    2011-04-15

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

  18. Tree-ring responses to extreme climate events as benchmarks for terrestrial dynamic vegetation models

    Directory of Open Access Journals (Sweden)

    A. Rammig

    2014-02-01

    Full Text Available Climate extremes can trigger exceptional responses in terrestrial ecosystems, for instance by altering growth or mortality rates. Effects of this kind are often manifested in reductions of the local net primary production (NPP. Investigating a set of European long-term data on annual radial tree growth confirms this pattern: we find that 53% of tree ring width (TRW indices are below one standard deviation, and up to 16% of the TRW values are below two standard deviations in years with extremely high temperatures and low precipitation. Based on these findings we investigate if climate driven patterns in long-term tree growth data may serve as benchmarks for state-of-the-art dynamic vegetation models such as LPJmL. The model simulates NPP but not explicitly the radial tree ring growth, hence requiring a generic method to ensure an objective comparison. Here we propose an analysis scheme that quantifies the coincidence rate of climate extremes with some biotic responses (here TRW or simulated NPP. We find that the reduction in tree-ring width during drought extremes is lower than the corresponding reduction of simulated NPP. We identify ten extreme years during the 20th century in which both, model and measurements indicate high coincidence rates across Europe. However, we detect substantial regional differences in simulated and observed responses to extreme events. One explanation for this discrepancy could be that the tree-ring data have preferentially been sampled at more climatically stressed sites. The model-data difference is amplified by the fact that dynamic vegetation models are designed to simulate mean ecosystem responses at landscape or regional scale. However, we find that both model-data and measurements display carry-over effects from the previous year. We conclude that using radial tree growth is a good basis for generic model-benchmarks if the data are analyzed by scale-free measures such as coincidence analysis. Our study shows

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

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-02-28

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

  1. Describing rainfall in northern Australia using multiple climate indices

    Science.gov (United States)

    Wilks Rogers, Cassandra Denise; Beringer, Jason

    2017-02-01

    Savanna landscapes are globally extensive and highly sensitive to climate change, yet the physical processes and climate phenomena which affect them remain poorly understood and therefore poorly represented in climate models. Both human populations and natural ecosystems are highly susceptible to precipitation variation in these regions due to the effects on water and food availability and atmosphere-biosphere energy fluxes. Here we quantify the relationship between climate phenomena and historical rainfall variability in Australian savannas and, in particular, how these relationships changed across a strong rainfall gradient, namely the North Australian Tropical Transect (NATT). Climate phenomena were described by 16 relevant climate indices and correlated against precipitation from 1900 to 2010 to determine the relative importance of each climate index on seasonal, annual and decadal timescales. Precipitation trends, climate index trends and wet season characteristics have also been investigated using linear statistical methods. In general, climate index-rainfall correlations were stronger in the north of the NATT where annual rainfall variability was lower and a high proportion of rainfall fell during the wet season. This is consistent with a decreased influence of the Indian-Australian monsoon from the north to the south. Seasonal variation was most strongly correlated with the Australian Monsoon Index, whereas yearly variability was related to a greater number of climate indices, predominately the Tasman Sea and Indonesian sea surface temperature indices (both of which experienced a linear increase over the duration of the study) and the El Niño-Southern Oscillation indices. These findings highlight the importance of understanding the climatic processes driving variability and, subsequently, the importance of understanding the relationships between rainfall and climatic phenomena in the Northern Territory in order to project future rainfall patterns in the

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

    Science.gov (United States)

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

    2013-04-01

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

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

    Science.gov (United States)

    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.

  4. National vulnerability to extreme climatic events: the cases of electricity disruption in China and Japan

    OpenAIRE

    Jing-Li Fan; Qiao-Mei Liang; Xiao-Jie Liang; Hirokazu Tatano; Yoshio Kajitani; Yi-Ming Wei

    2014-01-01

    Extreme climatic events are likely to adversely affect many countries throughout the world, but the degrees among countries may be different. China and Japan are the countries with high incidences of extreme weather/disaster, both facing with the urgent task of addressing climate change. This study seeks to quantitatively compare the impacts of extreme climatic events on socio-economic systems (defined as vulnerability) of the two countries by simulating the consequences of hypothetical the s...

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    2016-03-01

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

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

    Science.gov (United States)

    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 ...

  8. Impacts of climate change on rainfall extremes and urban drainage systems

    National Research Council Canada - National Science Library

    Willems, Patrick

    2012-01-01

    Impacts of Climate Change on Rainfall Extremes and Urban Drainage provides a state-of-the-art overview of existing methodologies and relevant results related to the assessment of the climate change...

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    Aziz, F.

    2015-12-01

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

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

    Science.gov (United States)

    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.

  12. Exploring Connections between Global Climate Indices and African Vegetation Phenology

    Science.gov (United States)

    Brown, Molly E.; deBeurs, Kirsten; Vrieling, Anton

    2009-01-01

    Variations in agricultural production due to rainfall and temperature fluctuations are a primary cause of food insecurity on the continent in Africa. Agriculturally destructive droughts and floods are monitored from space using satellite remote sensing by organizations seeking to provide quantitative and predictive information about food security crises. Better knowledge on the relation between climate indices and food production may increase the use of these indices in famine early warning systems and climate outlook forums on the continent. Here we explore the relationship between phenology metrics derived from the 26 year AVHRR NDVI record and the North Atlantic Oscillation index (NAO), the Indian Ocean Dipole (IOD), the Pacific Decadal Oscillation (PDO), the Multivariate ENSO Index (MEI) and the Southern Oscillation Index (SOI). We explore spatial relationships between growing conditions as measured by the NDVI and the five climate indices in Eastern, Western and Southern Africa to determine the regions and periods when they have a significant impact. The focus is to provide a clear indication as to which climate index has the most impact on the three regions during the past quarter century. We found that the start of season and cumulative NDVI were significantly affected by variations in the climate indices. The particular climate index and the timing showing highest correlation depended heavily on the region examined. The research shows that climate indices can contribute to understanding growing season variability in Eastern, Western and Southern Africa.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  15. Future tendencies of climate indicators important for adaptation and mitigation strategies in forestry

    Science.gov (United States)

    Galos, Borbala; Hänsler, Andreas; Gulyas, Krisztina; Bidlo, Andras; Czimber, Kornel

    2014-05-01

    Climate change is expected to have severe impacts in the forestry sector, especially in low-elevation regions in Southeast Europe, where forests are vulnerable and sensitive to the increasing probability and severity of climatic extremes, especially to droughts. For providing information about the most important regional and local risks and mitigation options for the Carpathian basin, a GIS-supported Decision Support System is under development. This study focuses on the future tendencies of climate indicators that determine the distribution, growth, health status and production of forests as well as the potential pests and diseases. For the analyses the climate database of the Decision Support System has been applied, which contains daily time series for precipitation and temperature means and extremes as well as derived climate indices for 1961-2100. For the future time period, simulation results of 12 regional climate models are included (www.ensembles-eu.org) based on the A1B emission scenario. The main results can be summarized as follows: · The projected change of the climate indices (e.g. total number of hot days, frost days, dry days, consecutive dry periods) and forestry indices (e.g. Ellenberg climate quotient, Forestry aridity index; Tolerance index for beech) indicates the warming and drying of the growing season towards the end of the 21st century. These can have severe consequences on the ecosystem services of forests. · The climatic suitable area of the native tree species is projected to move northwards and upwards in the mountains, respectively. For beech (Fagus sylvatica L.) this shift would mean the drastic shrink of the distribution area in the analyzed region. · The characteristic climate conditions that are expected in the Carpathian basin in the second half of the century, are now located southeastern from the case study region. In this way, the potential future provenance regions can be determined. Results provide input for the climate

  16. NASA indicators research in support of the National Climate Assessment

    Science.gov (United States)

    Leidner, A. K.; Houser, P. R.; Tsaoussi, L.

    2013-12-01

    Indicators have the potential to concisely communicate to a broad audience the observed and projected climate trends and anomalies, as well as society's vulnerability and ability to adapt to climate change. Consequently, indicators are anticipated to play an important role in the Fourth U.S. National Climate Assessment (NCA) report, slated to be released in four years. The NCA objectives include providing information about observed and anticipated changes in climate and assessing the impacts for regions and sectors, in order to help the nation prepare for a changing climate. Efforts are underway within the NCA to identify a set physical, ecological, and societal climate change indicators, by leveraging existing indicators currently in use by federal agencies. The NCA indicators are intended to provide meaningful and authoritative measures about the status and trends of climate for decision makers and the public. As a complement to this effort, and to support the NCA sustained assessment process, NASA solicited membership for an Indicators System Team and selected fourteen projects to begin research in summer 2013. These teams will develop and test potential new indicators that align with the vision set forth by the NCA, by combining NASA's remote sensing and modeling data products with additional datasets. Here, we further describe the objectives of the research program and highlight preliminary findings of several key projects related to physical, ecological, and societal climate change indicators, and discuss future research activities. Ultimately, this research will be made available in the peer-reviewed literature so that the newly developed indicators have the potential to be included in future NCA reports.

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

    Directory of Open Access Journals (Sweden)

    Antonius G T Schut

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

  18. Self-organized criticality of power system faults and its application in adaptation to extreme climate

    Institute of Scientific and Technical Information of China (English)

    SU Sheng; LI YinHong; DUAN XianZhong

    2009-01-01

    This paper analyzes the statistics of faults in a transmission and distribution networks in central China, unveils long-term autocorrelation and power law distribution of power system faults, which indicates that power system fault has self-organized criticality (SOC) feature. The conclusion is consistent with the power systems data in 2008 with ice storm present. Since power systems cover large areas, climate is the key factor to its safety and stability. In-depth analysis shows that the SOC of atmosphere system contributes much to that of power system faults. Extreme climate will be more intense and frequent with global warming, it will have more and more impact upon power systems. The SOC feature of power system faults is utilized to develop approaches to facilitate power systems adaptation to climate varia-tion in an economical and efficient way.

  19. Climate Change Indicators in the United States, 2016

    Science.gov (United States)

    EPA partners with over 40 data contributors from various government agencies, academic institutions, and other organizations to compile and communicate key indicators related to the causes and effects of climate change, the significance of these changes, and their possible conseq...

  20. Climate Change Indicators in the United States, 2016

    Science.gov (United States)

    EPA partners with over 40 data contributors from various government agencies, academic institutions, and other organizations to compile and communicate key indicators related to the causes and effects of climate change, the significance of these changes, and their possible conseq...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2015-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-11-01

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

  4. Impact of Climate Change on Hydrologic Extremes in the Upper Basin of the Yellow River Basin of China

    Directory of Open Access Journals (Sweden)

    Jun Wang

    2016-01-01

    Full Text Available To reveal the revolution law of hydrologic extremes in the next 50 years and analyze the impact of climate change on hydrologic extremes, the following main works were carried on: firstly, the long duration (15 d, 30 d, and 60 d rainfall extremes according to observed time-series and forecast time-series by dynamical climate model product (BCC-CSM-1.1 were deduced, respectively, on the basis that the quantitative estimation of the impact of climate change on rainfall extremes was conducted; secondly, the SWAT model was used to deduce design flood with the input of design rainfall for the next 50 years. On this basis, quantitative estimation of the impact of climate change on long duration flood volume extremes was conducted. It indicates that (1 the value of long duration rainfall extremes for given probabilities (1%, 2%, 5%, and 10% of the Tangnaihai basin will rise with slight increasing rate from 1% to 6% in the next 50 years and (2 long duration flood volume extremes of given probabilities of the Tangnaihai basin will rise with slight increasing rate from 1% to 6% in the next 50 years. The conclusions may provide technical supports for basin level planning of flood control and hydropower production.

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

    Science.gov (United States)

    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.

  6. Recent trends of extreme precipitation indices in the Iberian Peninsula using observations and WRF model results

    Science.gov (United States)

    Bartolomeu, S.; Carvalho, M. J.; Marta-Almeida, M.; Melo-Gonçalves, P.; Rocha, A.

    2016-08-01

    Spatial and temporal distributions of the trends of extreme precipitation indices were analysed between 1986 and 2005, over the Iberian Peninsula (IP). The knowledge of the patterns of extreme precipitation is important for impacts assessment, development of adaptation and mitigation strategies. As such, there is a growing need for a more detailed knowledge of precipitation climate change. This analysis was performed for Portuguese and Spanish observational datasets and results performed by the Weather Research and Forecast (WRF) model forced by the ERA-Interim reanalysis. Extreme precipitation indices recommended by the Expert Team for Climate Change Detection Monitoring and Indices were computed, by year and season. Then, annual and seasonal trends of the indices were estimated by Theil-Sen method and their significance was tested by the Mann-Kendal test. Additionally, a second simulation forced by the Max Planck Institute Earth System Model (MPI-ESM), was considered. This second modelling configuration was created in order to assess its performance when simulating extremes of precipitation. The annual trends estimated for the 1986-2005, from the observational datasets and from the ERA-driven simulation reveal: 1) negative statistically significant trends of the CWD index in the Galicia and in the centre of the IP; 2) positive statistically significant trends of the CDD index over the south of the IP and negative statistically significant trends in Galicia, north and centre of Portugal; 3) positive statistically significant trends of the R75p index in some regions of the north of the IP; 4) positive statistically significant trends in the R95pTOT index in the Central Mountains Chain, Leon Mountains and in the north of Portugal. Seasonally, negative statistically significant trends of the CWD index were found in Galicia, in winter and in the south of the IP, in summer. Positive statistically significant trends of the CWD index were identified in the Leon Mountains

  7. Identifying climate analogues for precipitation extremes for Denmark based on RCM simulations from the ENSEMBLES database

    DEFF Research Database (Denmark)

    Arnbjerg-Nielsen, Karsten; Funder, S. G.; Madsen, H.

    2015-01-01

    change over time. The study focuses on assessing climate analogues for Denmark based on current climate data set (E-OBS) observations as well as the ENSEMBLES database of future climates with the aim of projecting future precipitation extremes. The local present precipitation extremes are assessed......Climate analogues, also denoted Space-For-Time, may be used to identify regions where the present climatic conditions resemble conditions of a past or future state of another location or region based on robust climate variable statistics in combination with projections of how these statistics...

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

    Science.gov (United States)

    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

  9. Regional climate extremes in Northern Eurasia associated with atmospheric blockings: Interannual variations and tendencies of change

    Science.gov (United States)

    Mokhov, I.; Akperov, M.; Lupo, A. R.; Chernokulsky, A. V.; Timazhev, A.

    2011-12-01

    Large regional climate anomalies associated with atmospheric blockings have been noted during last years in Northern Eurasia. Impact of blockings is exhibited in such extremes as heat and cold waves, droughts, and forest fires. In order to detect changes in the blocking activity characteristics an analysis of different data for the Northern Hemisphere with the use of various methods for blockings detection was carried out. In particular, the data for 500 hPa geopotential from the NCEP/NCAR Reanalysis 1 (1948-2010) and NOAA-CIRES 20th Century Reanalysis v2 (1871-2008) have been used as well as climate model simulations for the 20th and 21st centuries with anthropogenic forcing. Special attention is paid to the analysis of extreme dry conditions in the Northern Eurasia regions and to the 2010 Russian heat wave associated to atmospheric blockings with the use observational data (1891-2010) for surface air temperature, precipitation and different indices for the drought conditions. Tendencies of change and interannual variations are analyzed with an assessment of effects of El-Nino/La-Nina phenomena. Possibility of intensification of blocking-associated climate impacts under global warming is discussed. Changes of blocking characteristics and associated regional climate anomalies in the 21st century based on model simulations with anthropogenic scenarios are analyzed.

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

    Science.gov (United States)

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

    2016-06-01

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

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

    Science.gov (United States)

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

    2013-12-01

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

  12. Extreme edge-friendly indices of complete bipartite graphs

    Directory of Open Access Journals (Sweden)

    Wai Chee Shiu

    2016-09-01

    Full Text Available Let G=(V,E be a simple graph. An edge labeling f:E to {0,1} induces a vertex labeling f^+:V to Z_2 defined by $f^+(vequiv sumlimits_{uvin E} f(uvpmod{2}$ for each $v in V$, where Z_2={0,1} is the additive group of order 2. For $iin{0,1}$, let e_f(i=|f^{-1}(i| and v_f(i=|(f^+^{-1}(i|. A labeling f is called edge-friendly if $|e_f(1-e_f(0|le 1$. I_f(G=v_f(1-v_f(0 is called the edge-friendly index of G under an edge-friendly labeling f. Extreme values of edge-friendly index of complete bipartite graphs will be determined.

  13. Extremities--indications and techniques for treatment of extremity vascular injuries.

    Science.gov (United States)

    Doody, O; Given, M F; Lyon, S M

    2008-11-01

    Traumatic vascular injuries involving the extremity are rare and penetrating trauma accounts for the majority of such injuries. The remaining arterial injuries are as a result of either blunt or iatrogenic injuries. The rapid detection, localisation and characterisation of vascular injuries in patients who have a traumatic extremity injury is essential for the effective management and treatment of such injuries. This review will discuss the expanding role of multi-detector computed tomography angiography in diagnosing vascular injuries and its implications on conventional diagnostic angiography. The roles of other non-invasive imaging modalities are reviewed. The presentation and types of vascular injuries in blunt and penetrating injuries are discussed. While surgery remains the gold standard in the management of vascular extremity injuries it has significant morbidity rates. Endovascular techniques are increasingly being used for the treatment of vascular traumatic injuries and various techniques including balloon occlusion, embolisation and stent/stent graft placement are discussed.

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

    Science.gov (United States)

    Serykh, Ilya; Kostianoy, Andrey

    2016-04-01

    (depending on the parameters) in the territory and water area of Russia for determining and mapping of the observed characteristics and trends in the extreme climate events and statistical forecast of these events for the next decades. Determination of a frequency, intensity and duration of extreme climate events in the territory and water area of Russia was done for the first time. It was found that the interannual-scale dynamics of ENSO is actually reflected in the climate features of different regions of the Earth, including the Russian Arctic. In particular, when the boreal winter season coincides with an El Niño event it is indicative by a negative anomaly of near-surface temperature (about -1°C) and a positive anomaly of sea level pressure over the Russian Western Arctic Basin. In contrary, significant (about +1°C) positive anomaly of near-surface temperature along with reduced sea level pressure over the regions of the Barents, White and Kara Seas is typical for any La Niña event (up to 95% significance of Student's t-test). The study was carried out with a support of the Russian Science Foundation Grant (Project N 14-50-00095).

  15. Indicators and metrics for the assessment of climate engineering

    Science.gov (United States)

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

    2017-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Linda Munson

    Full Text Available 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

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

    Science.gov (United States)

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

    2015-12-01

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

  18. Impacts of Multi-Scale Solar Activity on Climate.Part Ⅰ:Atmospheric Circulation Patterns and Climate Extremes

    Institute of Scientific and Technical Information of China (English)

    Hengyi WENG

    2012-01-01

    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 renoving the influence from the El Ni(n)o-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 compared with

  19. Exploring the Ocean Through Climate Indicators: What Do Research, Predictions, and Decision-makers Need to Know?

    Science.gov (United States)

    Arrigo, J. S.

    2015-12-01

    There are several new and ongoing efforts around communicating climate and global change and variability by developing Climate Indicators (e.g. the US Global Change Research Project's Pilot Indicators Program, the US EPA's Climate Change Indicators, and the Ocean Observations Panel for Climate State of the Ocean indicators). Indicators provide information tailored to identified stakeholders and facilitate monitoring status, trends, extremes and variability of important climate features or processes. NOAA's Climate Monitoring program is in the middle of a three-year initiative toward supporting research toward the development of Ocean Climate Indicators for research, prediction, and decision makers. These indices combine ocean observations, climate data and products from platforms like (but not limited to) the drifting buoy, Argo, satellite, and buoy arrays that provide fundamental observations that contribute towards climate understanding, predictions, and projections. The program is supporting eight distinct projects that focus on primarily regional indices that target varied stakeholders and outreach strategies - from public awareness and education to targeted model performance improvement. This presentation will discuss the diverse set of projects, initial results, and discuss possibilities for and examples of using the indicators and processes for developing them for broader science outreach and education, with an eye toward the aim of organizing the ocean climate and observing community around developing a comprehensive ocean monitoring and indicators system.

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

    Directory of Open Access Journals (Sweden)

    Mingcai Li

    Full Text Available 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.

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2016-08-01

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

  3. Effects of climate model interdependency on the uncertainty quantification of extreme rainfall projections

    DEFF Research Database (Denmark)

    Sunyer Pinya, Maria Antonia; Madsen, H.; Rosbjerg, Dan;

    Changes in rainfall extremes under climate change conditions are subject to numerous uncertainties. One of the most important uncertainties arises from the inherent uncertainty in climate models. In recent years, many efforts have been made in creating large multi-model ensembles of both Regional...... Climate Models (RCMs) and General Circulation Models (GCMs). These multi-model ensembles provide the information needed to estimate probabilistic climate change projections. Several probabilistic methods have been suggested. One common assumption in most of these methods is that the climate models...... of accounting for the climate model interdependency when estimating the uncertainty of climate change projections....

  4. Extreme waves from Nortes and climate change in the Gulf of Mexico

    Science.gov (United States)

    Appendini, Christian M.; Hernández-Lasheras, Jaime; Pedrozo-Acuña, Adrian; Meza-Padilla, Rafael

    2017-04-01

    Extreme ocean waves in the Gulf of Mexico are a result from the incidence of tropical cyclones and anticyclone systems known as Nortes. While the waves derived from tropical cyclones have devastating consequences but a low probability of occurrence, Nortes are a frequent phenomenon producing disruptions of maritime activities during autumn/winter months. In this study we present an assessment of the waves generated by Nortes and the effects of a warming climate. To do so, we first developed a methodology to identify Norte events and classify them according to their effect over the sea state. A new index is proposed to identify events, which was used to identify events in the present and future climates. A third generation wave model was run for each of the events identified in the CFSR reanalysis and the CMIP5 model CNRM-M5 under the RCP 8.5 scenario. Nortes were classified into 5 types, using both principal component analysis and a cluster analysis by k-means over the computed wave power of the individual events. An assessment of the effect of climate change was performed over the different Norte types, which indicated that climate change will result in less frequent events of higher intensity and more frequent mild events. This may provide a relief for coastal and marine operations, in relation to downtimes due to extreme wave conditions, so that the operational design of maritime structures could consider a lower occurrence of extreme events as a result of Nortes. While the results are not conclusive due to the uncertainty imposed by Global Circulation Models, this study provides the methodology to perform the assessment on other models to reduce uncertainty.

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

    Science.gov (United States)

    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.

  6. Daily extreme precipitation indices and their impacts on rice yield—A case study over the tropical island in China

    Science.gov (United States)

    Li, Mao-Fen; Luo, Wei; Li, Hailiang; Liu, Enping; Li, Yuping

    2017-03-01

    Frequent occurrences of extreme precipitation events have significant impacts on agricultural production. Tropical agriculture has been playing an important role in national economy in China. A precise understanding of variability in extreme precipitation indices and their impacts on crop yields are of great value for farmers and policy makers at county level, particularly in tropical China where almost all agriculture is rainfed. This research has studied observed trends in extreme precipitation indices (a total of 10) during 1988-2013 over Hainan island, tropical China. Mann-Kendall nonparametric test was adopted for trend detection and the results showed that most of precipitation indices showed increasing trend. Since rice is the most important staple food in Hainan island, the impacts of extreme precipitation indices on rice yields were also analyzed through simple correlations. In general, the rainy days and rain intensity in late rice growing season showed increasing trend over Hainan island. The rice yield presented ninth-degree polynomial technological trend at all stations and increasing trend for early rice yield. Late rice yield showed a decreasing trend in some parts of Hainan island. Spearman rank correlation coefficient indicated that the correlation was more pronounced between extreme precipitation indices and yields at Haikou site for early rice, and Haikou, Sanya, and Qionghai stations for late rice, respectively. Further results also indicated that there were statistically significant positive trends of R10 and R20 (number of days with precipitation ≥10 mm and precipitation ≥20 mm, respectively) from July to November at Haikou (located in north of Hainan island), and this positive trend may be a disadvantage for late rice yield. The cut-off value of extreme precipitation indices and its correlation with rice yield anomaly indices for Hainan island provided a foundation for vulnerability assessment as well as a contribution to set up

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

    Science.gov (United States)

    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

  8. Effect of climate change and variability on extreme rainfall intensity–frequency–duration relationships: a case study of Melbourne

    Directory of Open Access Journals (Sweden)

    A. G. Yilmaz

    2014-06-01

    Full Text Available The increased frequency and magnitude of extreme rainfall events due to anthropogenic climate change, and decadal and multi-decadal climate variability question the stationary climate assumption. The possible violation of stationarity in climate can cause erroneous estimation of design rainfalls derived from extreme rainfall frequency analysis. This may result in significant consequences for infrastructure and flood protection projects since design rainfalls are essential input for design of these projects. Therefore, there is a need to conduct frequency analysis of extreme rainfall events in the context of non-stationarity, when non-stationarity is present in extreme rainfall events. A methodology consisting of, threshold selection, extreme rainfall data (peaks over threshold data construction, trend and non-stationarity analysis, and stationary and non-stationary Generalized Pareto Distribution (GPD models was developed in this paper to investigate trends and non-stationarity in extreme rainfall events, and potential impacts of climate change and variability on Intensity–Frequency–Duration (IFD relationships. The developed methodology was successfully implemented using rainfall data from an observation station in Melbourne (Australia for storm durations ranging from 6 min to 72 h. Although statistically significant trends were detected in extreme rainfall data for storm durations of 30 min, and 3 and 48 h, statistical non-stationarity tests and non-stationary GPD models did not indicate non-stationarity for these storm durations and other storm durations. It was also found that the stationary GPD models were capable of fitting extreme rainfall data for all storm durations. Furthermore, the IFD analysis showed that urban flash flood producing hourly rainfall intensities have increased over time.

  9. Methods for extracting climate indicator data from social media.

    Science.gov (United States)

    Fuka, M. Z.; Fuka, D. R.

    2011-12-01

    This paper shows how we've used the R software suite to extract climate indicator data from Twitter. In the course of this research we've collected extensive data sets of unsolicited observations ("tweets") for hundreds of climate-related phenological, biological, epidemiological and meteorological effects. R has proved itself in our work as a useful tool for manipulating those large data sets. Our experience from this effort has yielded a variety of insights on using R to extract geophysics-specific information from publicly accessible social media sources. We illustrate our methodology by mapping tweeted US armadillo sightings to explore the impact of climate variability on the extent of the animal's range. This example usefully demonstrates R's technical capabilities in collecting, time-stamping, geolocating, analyzing, visualizing and otherwise processing climate-related data derived from unsolicited social media postings. We also "mash-up" the data sets with those acquired by more traditional means, for example, temperature and precipitation data across the armadillo's US range. Our data-handling practice is extendable to social sharing services other than Twitter, providing the environmental modeling community an opportunity to access largely untapped resources of non-traditional climate indicator data to better understand the effects of climate change at local, regional and global scales.

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

    Energy Technology Data Exchange (ETDEWEB)

    Brunsell, Nathaniel [Univ. of Kansas, Lawrence, KS (United States); Mechem, David [Univ. of Kansas, Lawrence, KS (United States); Ma, Chunsheng [Wichita State Univ., KS (United States)

    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

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

    OpenAIRE

    Angelo Rita; Marco Borghetti; Luigi Todaro; Antonio Saracino

    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 condit...

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

    Science.gov (United States)

    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

  13. Interpreting the climatic effects on xylem functional traits in two Mediterranean oak species: the role of extreme climatic events

    Directory of Open Access Journals (Sweden)

    Angelo Rita

    2016-08-01

    Full Text Available 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

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

    Science.gov (United States)

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

    2017-01-01

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

  15. Climate and desertification: indicators for an assessment methodology

    Energy Technology Data Exchange (ETDEWEB)

    Sciortino, M.; Caiaffa, E.; Fattoruso, G.; Donolo, R.; Salvetti, G.

    2009-07-01

    This work aims to define a methodology that, on the basis of commonly available surface climate records, assesses indicators of the increase or decrease of the extension of territories vulnerable to desertification and land degradation. The definition and quantification of environmental policy relevant indicators aims to improve the understanding and the decision making processes in dry lands. the results of this study show that since 1931 changes of climate involved 90% of the territory of the Sicilian region, with stronger intensity in the internal areas of Enna, Caltanissetta and Palermo provinces. (Author) 9 refs.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  18. Improving predictions and management of hydrological extremes through climate services

    NARCIS (Netherlands)

    Hurk, van den Bart J.J.M.; Bouwer, Laurens M.; Buontempo, Carlo; Döscher, Ralf; Ercin, Ertug; Hananel, Cedric; Hunink, Johannes E.; Kjellström, Erik; Klein, Bastian; Manez, Maria; Pappenberger, Florian; Pouget, Laurent; Ramos, Maria Helena; Ward, Philip J.; Weerts, Albrecht H.; Wijngaard, Janet B.

    2016-01-01

    The EU Roadmap on climate services can be seen as a result of a convergence between the society's call for "actionable research", and the ability of the climate research community to provide tailored data, information and knowledge. However, although weather and climate have clearly distinct defi

  19. Improving predictions and management of hydrological extremes through climate services

    NARCIS (Netherlands)

    Hurk, van den Bart J.J.M.; Bouwer, Laurens M.; Buontempo, Carlo; Döscher, Ralf; Ercin, Ertug; Hananel, Cedric; Hunink, Johannes E.; Kjellström, Erik; Klein, Bastian; Manez, Maria; Pappenberger, Florian; Pouget, Laurent; Ramos, Maria Helena; Ward, Philip J.; Weerts, Albrecht H.; Wijngaard, Janet B.

    2016-01-01

    The EU Roadmap on climate services can be seen as a result of a convergence between the society's call for "actionable research", and the ability of the climate research community to provide tailored data, information and knowledge. However, although weather and climate have clearly distinct

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

    DEFF Research Database (Denmark)

    Arnbjerg-Nielsen, Karsten; Gregersen, Ida Bülow; Sunyer Pinya, Maria Antonia

    2014-01-01

    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...... 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...... are discussed. Accounting for the uncertainty introduced by these factors a 10-year event is expected to increase by 30% over a projection period of 100 years. This is less than the variation within one natural oscillation cycle, indicating that it is crucial to understand and account for the future multi...

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

    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.

  3. Impacts of extreme climate on simulated runoff in the Yellow River Basin

    Science.gov (United States)

    Tang, Y.; Tang, Q.

    2011-12-01

    Historical observations show that extreme climate events have increased in frequency in the Yellow River Basin. The Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4) projects higher climate variability in a warmer climate, suggesting an increase of extreme climate frequency in the 21st century. The responses of available water resources to the extreme climate remain relatively unexplored in the Yellow River Basin. This study examines the change in the climate extreme and its impacts on streamflow using a long time series of runoff estimated from the Soil and Water Assessment Tool (SWAT) model. The linear regression and the Mann-Kendall non-parameter statistical method are used to detect the change trend in climate (primary precipitation and temperature) extreme frequency and intensity. Three SWAT simulations are conducted. The first simulation is a control SWAT experiment using the observed climate data. The second simulation is driven by a de-trended climate data in which the linear trend is removed and the mean values are fixed to the means of the first decade. The third simulation is a stable simulation where climate conditions repeated from the first decade. The trends of the simulated runoff are analyzed and compared. The effects of changes in the temporal climate pattern and mean climate condition are computed from the estimated runoff trends. The differences between the SWAT simulations represent the contribution of the change to the alteration of the simulated runoff. Our preliminary results suggest that the extreme precipitation has significantly changed the simulated runoff both in the flow frequency and mean value.

  4. Projected changes in mean and extreme precipitation indices over India using PRECIS

    Science.gov (United States)

    Rao, K. Koteswara; Patwardhan, S. K.; Kulkarni, Ashwini; Kamala, K.; Sabade, S. S.; Kumar, K. Krishna

    2014-02-01

    The impact of global warming on the characteristics of mean and extremes of rainfall over India is investigated using a high resolution regional climate model PRECIS developed by Hadley Centre, UK. Five simulations of PRECIS made using the lateral boundary conditions from a suite of Perturbed Physics Ensembles (PPE) generated using Hadley Center Coupled Model (HadCM3) for Quantifying Uncertainty in Model Predictions (QUMP) project corresponding to IPCC A1B emission scenario have been analyzed here for this purpose. The projected changes depict seasonally dependent fine scale structure in response to the topographic forcing and changes in circulation, especially along the west coast and North East (NE) region of India towards the end of the 21st century i.e. 2080s (2071-2098). Analysis of the extreme precipitation indices indicates an increase in the intensity of rainfall on wet days towards 2080s under A1B scenario. Changes in extreme precipitation events and dry spells suggest not only shifts, but also a substantial increase in the spread of the precipitation distribution, with an increased probability of the occurrence of events conducive to both floods and droughts. The projected changes in various precipitation extremes show a large regional variability. Total rainfall on very heavy rainy days (R95p) is projected to increase by around 40-50% over the central parts of the country. The number of rainy days > 10 mm (R10) may increase by 10-20% over west coast, east central India and northeastern parts while over northwest and rain shadow region they may increase by 40-50%. The consecutive dry days (CDDs) may decrease by 10-20% over Indo-Gangetic plain, however over west coast there may not be any significant change. The CDDs are projected to rise by 10-20% over west central and peninsular India. The precipitation per wet day (SDII) may be more intense by 10-40% over the entire land mass, however there may not be any significant change over south peninsular India.

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

    Science.gov (United States)

    2017-01-01

    Climate change represents a significant and growing threat to population health. Rural areas face unique challenges, such as high rates of vulnerable populations; economic uncertainty due to their reliance on industries that are vulnerable to climate change; less resilient infrastructure; and lower levels of access to community and emergency services than urban areas. This article fills a gap in public health practice by developing climate and health environmental public health indicators for a local public health department in a rural area. We adapted the National Environmental Public Health Tracking Network's framework for climate and health indicators to a seven-county health department in Western Kentucky. Using a three-step review process, we identified primary climate-related environmental public health hazards for the region (extreme heat, drought, and flooding) and a suite of related exposure, health outcome, population vulnerability, and environmental vulnerability indicators. Indicators that performed more poorly at the county level than at the state and national level were defined as “high vulnerability.” Six to eight high vulnerability indicators were identified for each county. The local health department plans to use the results to enhance three key areas of existing services: epidemiology, public health preparedness, and community health assessment. PMID:28352286

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

    Science.gov (United States)

    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.

  7. Drought forecasting in Luanhe River basin involving climatic indices

    Science.gov (United States)

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

    2016-09-01

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

  8. Understanding the Reach of Agricultural Impacts from Climate Extremes in the Agricultural Model Intercomparison and Improvement Project (AgMIP)

    Science.gov (United States)

    Ruane, A. C.

    2016-12-01

    The Agricultural Model Intercomparison and Improvement Project (AgMIP) has been working since 2010 to build a modeling framework capable of representing the complexities of agriculture, its dependence on climate, and the many elements of society that depend on food systems. AgMIP's 30+ activities explore the interconnected nature of climate, crop, livestock, economics, food security, and nutrition, using common protocols to systematically evaluate the components of agricultural assessment and allow multi-model, multi-scale, and multi-method analysis of intertwining changes in socioeconomic development, environmental change, and technological adaptation. AgMIP is now launching Coordinated Global and Regional Assessments (CGRA) with a particular focus on unforeseen consequences of development strategies, interactions between global and local systems, and the resilience of agricultural systems to extreme climate events. Climate extremes shock the agricultural system through local, direct impacts (e.g., droughts, heat waves, floods, severe storms) and also through teleconnections propagated through international trade. As the climate changes, the nature of climate extremes affecting agriculture is also likely to change, leading to shifting intensity, duration, frequency, and geographic extents of extremes. AgMIP researchers are developing new scenario methodologies to represent near-term extreme droughts in a probabilistic manner, field experiments that impose heat wave conditions on crops, increased resolution to differentiate sub-national drought impacts, new behavioral functions that mimic the response of market actors faced with production shortfalls, analysis of impacts from simultaneous failures of multiple breadbasket regions, and more detailed mapping of food and socioeconomic indicators into food security and nutrition metrics that describe the human impact in diverse populations. Agricultural models illustrate the challenges facing agriculture, allowing

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

    Science.gov (United States)

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

    2011-01-01

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

  10. Impact of climate extremes on flowering dates of four shrub species

    Science.gov (United States)

    Siegmund, Jonatan; Wiedermann, Marc; Donges, Jonathan; Donner, Reik

    2016-04-01

    Ongoing climate change is known to cause an increase in frequency and amplitude of local temperature and precipitation extremes in central Europe. While gradual changes in the climatological conditions are known to strongly influence plant flowering dates, the question arises if and how extremes specifically impact the timing of this important phenological phase. In this study, we systematically quantify simultaneities between meteorological extremes and the timing of flowering of four shrub species across Germany by means of event coincidence analysis, a novel statistical tool that allows assessing whether or not two types of events exhibit similar sequences of occurrences. Additionally we perform a superimposed epoch analysis in order to investigate the impact of different magnitudes of extremes and to assess possible long term influences. Our systematic investigation supports previous findings of experimental studies by highlighting the impact of early spring temperatures on the flowering of wildlife plants. In addition, we find statistically significant indications for some long-term relations reaching back to the previous year.

  11. Climate Products and Services to Meet the Challenges of Extreme Events

    Science.gov (United States)

    McCalla, M. R.

    2008-12-01

    The 2002 Office of the Federal Coordinator for Meteorological Services and Supporting Research (OFCM1)-sponsored report, Weather Information for Surface Transportation: National Needs Assessment Report, addressed meteorological needs for six core modes of surface transportation: roadway, railway, transit, marine transportation/operations, pipeline, and airport ground operations. The report's goal was to articulate the weather information needs and attendant surface transportation weather products and services for those entities that use, operate, and manage America's surface transportation infrastructure. The report documented weather thresholds and associated impacts which are critical for decision-making in surface transportation. More recently, the 2008 Climate Change Science Program's (CCSP) Synthesis and Assessment Product (SAP) 4.7 entitled, Impacts of Climate Change and Variability on Transportation Systems and Infrastructure: Gulf Coast Study, Phase I, included many of the impacts from the OFCM- sponsored report in Table 1.1 of this SAP.2 The Intergovernmental Panel on Climate Change (IPCC) reported that since 1950, there has been an increase in the number of heat waves, heavy precipitation events, and areas of drought. Moreover, the IPCC indicated that greater wind speeds could accompany more severe tropical cyclones.3 Taken together, the OFCM, CCSP, and IPCC reports indicate not only the significance of extreme events, but also the potential increasing significance of many of the weather thresholds and associated impacts which are critical for decision-making in surface transportation. Accordingly, there is a real and urgent need to understand what climate products and services are available now to address the weather thresholds within the surface transportation arena. It is equally urgent to understand what new climate products and services are needed to address these weather thresholds, and articulate what can be done to fill the gap between the

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  14. Tropical Glaciers: Recorders and Indicators of Climate Change

    Science.gov (United States)

    Thompson, L. G.; Mosley-Thompson, E. S.; Buffen, A.; Urmann, D.; Davis, M. E.; Lin, P.

    2008-12-01

    Tropical climate is dominated on interannual time scales by monsoons and especially by ENSO, which is responsible for meteorological phenomena that directly or indirectly affect most regions on the planet and their populations. Common tropical teleconnections to the extra tropics include a stronger Aleutian low, stronger westerlies, variations in convective activity (flooding and drought), and modulation of tropical storm intensities. New ice core records from the Quelccaya and Coropuna ice caps provide 1700 years of continuous, annually-resolved records of climate and environmental variability expressed in the oxygen and hydrogen isotopic ratios, concentrations of mineral dust and various chemical species and net mass accumulation. These records provide an opportunity to examine the nature of tropical climate variability in greater detail, and to extract new information on ENSO and monsoon-linked climate phenomena. Quelccaya records display a prominent Little Ice Age isotopic depletion from 1520 to 1880 A.D. and a muted Medieval Warming between 1100 and 1300 AD. Drier conditions dominated from 300 to 500 AD, 1190 to 1470 AD and 1710 to 1910 with slightly wetter conditions from 500 to 1190 AD, and much wetter conditions from 1470 to 1710 A.D. and from 1910 A.D. to the present. The major cation and anion concentrations record other environmental changes over the past 1700 years. The longer tropical climate histories from Coropuna and Huascarán (Peru), Sajama (Bolivia), and Kilimanjaro (Tanzania) document abrupt climate disruptions such as the 4.2 ka drought and an extreme cold and wet period centered at 5.2 ka. The well documented ongoing ice loss on Quelccaya and Kilimanjaro paint a grim future for glacier histories from the tropics. The current melting of high-altitude, low-latitude ice fields is consistent with model predictions for a vertical amplification of temperature in the tropics. The ongoing glacier retreat in the Andes, Himalayas and Africa has

  15. Past and future climate change in the context of memorable seasonal extremes

    Directory of Open Access Journals (Sweden)

    T. Matthews

    2016-01-01

    Full Text Available It is thought that direct personal experience of extreme weather events could result in greater public engagement and policy response to climate change. Based on this premise, we present a set of future climate scenarios for Ireland communicated in the context of recent, observed extremes. Specifically, we examine the changing likelihood of extreme seasonal conditions in the long-term observational record, and explore how frequently such extremes might occur in a changed Irish climate according to the latest model projections. Over the period (1900–2014 records suggest a greater than 50-fold increase in the likelihood of the warmest recorded summer (1995, whilst the likelihood of the wettest winter (1994/95 and driest summer (1995 has respectively doubled since 1850. The most severe end-of-century climate model projections suggest that summers as cool as 1995 may only occur once every ∼7 years, whilst winters as wet as 1994/95 and summers as dry as 1995 may increase by factors of ∼8 and ∼10 respectively. Contrary to previous research, we find no evidence for increased wintertime storminess as the Irish climate warms, but caution that this conclusion may be an artefact of the metric employed. It is hoped that framing future climate scenarios in the context of extremes from living memory will help communicate the scale of the challenge climate change presents, and in so doing bridge the gap between climate scientists and wider society.

  16. Detection and Attribution of Climate Change : From global mean temperature change to climate extremes and high impact weather.

    CERN Document Server

    CERN. Geneva

    2013-01-01

    This talk will describe how evidence has grown in recent years for a human influence on climate and explain how the Fifth Assessment Report of the Intergovernmental Panel on Climate Change concluded that it is extremely likely (>95% probability) that human influence on climate has been the dominant cause of the observed global-mean warming since the mid-20th century. The fingerprint of human activities has also been detected in warming of the ocean, in changes in the global water cycle, in reductions in snow and ice, and in changes in some climate extremes. The strengthening of evidence for the effects of human influence on climate extremes is in line with long-held basic understanding of the consequences of mean warming for temperature extremes and for atmospheric moisture. Despite such compelling evidence this does not mean that every instance of high impact weather can be attributed to anthropogenic climate change, because climate variability is often a major factor in many locations, especially for rain...

  17. Prevailing trends of climatic extremes across Indus-Delta of Sindh-Pakistan

    Science.gov (United States)

    Abbas, Farhat; Rehman, Iqra; Adrees, Muhammad; Ibrahim, Muhammad; Saleem, Farhan; Ali, Shafaqat; Rizwan, Muhammad; Salik, Muhammad Raza

    2017-01-01

    This study examines the variability and change in the patterns of climatic extremes experienced in Indus-Delta of Sindh province of Pakistan, comprising regions of Karachi, Badin, Mohenjodaro, and Rohri. The homogenized daily minimum and maximum temperature and precipitation data for a 36-year period were used to calculate 13 and 11 indices of temperature and precipitation extremes with the help of RClimDex, a program written in the statistical software package R. A non-parametric Mann-Kendall test and Sen's slope estimates were used to determine the statistical significance and magnitude of the calculated trend. Temperatures of summer days and tropical nights increased in the region with overall significant warming trends for monthly maximum temperature as well as for warm days and nights reflecting dry conditions in the study area. The warm extremes and nighttime temperature indices showed greater trends than cold extremes and daytime indices depicting an overall warming trends in the Delta. Historic decrease in the acreage of major crops and over 33% decrease in agriculture credit for Sindh are the indicators of adverse impacts of warmer and drier weather on Sindh agriculture. Trends reported for Karachi and Badin are expected to decrease rice cultivation, hatching of fisheries, and mangroves forest surrounding these cities. Increase in the prevailing temperature trends will lead to increasingly hotter and drier summers resulting to constraints on cotton, wheat, and rice yield in Rohri and Mohenjodaro areas due to increased crop water requirements that may be met with additional groundwater pumping; nonetheless, the depleted groundwater resources would have a direct impact on the region's economy.

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

    Science.gov (United States)

    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.

  19. Climatic and biotic extreme events moderate long-term responses of above- and belowground sub-Arctic heathland communities to climate change.

    Science.gov (United States)

    Bokhorst, Stef; Phoenix, Gareth K; Berg, Matty P; Callaghan, Terry V; Kirby-Lambert, Christopher; Bjerke, Jarle W

    2015-11-01

    Climate change impacts are not uniform across the Arctic region because interacting factors causes large variations in local ecosystem change. Extreme climatic events and population cycles of herbivores occur simultaneously against a background of gradual climate warming trends and can redirect ecosystem change along routes that are difficult to predict. Here, we present the results from sub-Arctic heath vegetation and its belowground micro-arthropod community in response to the two main drivers of vegetation damage in this region: extreme winter warming events and subsequent outbreaks of the defoliating autumnal moth caterpillar (Epirrita autumnata). Evergreen dwarf shrub biomass decreased (30%) following extreme winter warming events and again by moth caterpillar grazing. Deciduous shrubs that were previously exposed to an extreme winter warming event were not affected by the moth caterpillar grazing, while those that were not exposed to warming events (control plots) showed reduced (23%) biomass from grazing. Cryptogam cover increased irrespective of grazing or winter warming events. Micro-arthropods declined (46%) following winter warming but did not respond to changes in plant community. Extreme winter warming and caterpillar grazing suppressed the CO2 fluxes of the ecosystem. Evergreen dwarf shrubs are disadvantaged in a future sub-Arctic with more stochastic climatic and biotic events. Given that summer warming may further benefit deciduous over evergreen shrubs, event and trend climate change may both act against evergreen shrubs and the ecosystem functions they provide. This is of particular concern given that Arctic heath vegetation is typically dominated by evergreen shrubs. Other components of the vegetation showed variable responses to abiotic and biotic events, and their interaction indicates that sub-Arctic vegetation response to multiple pressures is not easy to predict from single-factor responses. Therefore, while biotic and climatic events may

  20. Climate Change: A New Metric to Measure Changes in the Frequency of Extreme Temperatures using Record Data

    Science.gov (United States)

    Munasinghe, L.; Jun, T.; Rind, D. H.

    2012-01-01

    Consensus on global warming is the result of multiple and varying lines of evidence, and one key ramification is the increase in frequency of extreme climate events including record high temperatures. Here we develop a metric- called "record equivalent draws" (RED)-based on record high (low) temperature observations, and show that changes in RED approximate changes in the likelihood of extreme high (low) temperatures. Since we also show that this metric is independent of the specifics of the underlying temperature distributions, RED estimates can be aggregated across different climates to provide a genuinely global assessment of climate change. Using data on monthly average temperatures across the global landmass we find that the frequency of extreme high temperatures increased 10-fold between the first three decades of the last century (1900-1929) and the most recent decade (1999-2008). A more disaggregated analysis shows that the increase in frequency of extreme high temperatures is greater in the tropics than in higher latitudes, a pattern that is not indicated by changes in mean temperature. Our RED estimates also suggest concurrent increases in the frequency of both extreme high and extreme low temperatures during 2002-2008, a period when we observe a plateauing of global mean temperature. Using daily extreme temperature observations, we find that the frequency of extreme high temperatures is greater in the daily minimum temperature time-series compared to the daily maximum temperature time-series. There is no such observable difference in the frequency of extreme low temperatures between the daily minimum and daily maximum.

  1. Trends and Bioclimatic Assessment of Extreme Indices: Emerging Insights for Rainfall Derivative Crop Microinsurance in Central-West Nigeria

    Science.gov (United States)

    Awolala, D. O.

    2015-12-01

    Scientific predictions have forecasted increasing economic losses by which farming households will be forced to consider new adaptation pathways to close the food gap and be income secure. Pro-poor adaptation planning decisions therefore must rely on location-specific details from systematic assessment of extreme climate indices to provide template for most suitable financial adaptation instruments. This paper examined critical loss point to water stress in maize production and risk-averse behaviour to extreme local climate in Central West Nigeria. Trends of extreme indices and bio-climatic assessment based on RClimDex for numerical weather predictions were carried out using a 3-decade time series daily observational climate data of the sub-humid region. The study reveals that the flowering and seed formation stage was identified as the most critical loss point when seed formation is a function of per unit soil water available for uptake. The sub-humid has a bi-modal rainfall pattern but faces longer dry spell with a fast disappearing mild climate measured by budyko evaporation of 80.1%. Radiation index of dryness of 1.394 confirms the region is rapidly becoming drier at an evaporation rate of 949 mm/year and rainfall deficit of 366 mm/year. Net primary production from rainfall is fast declining by 1634 g(DM)/m2/year. These conditions influenced by monthly rainfall uncertainties are associated with losses of standing crops because farmers are uncertain of rainfall probability distribution especially during most important vegetative stage. In a simulated warmer climate, an absolute dryness of months was observed compared with 4 dry months in a normal climate which explains triggers of food deficits and income losses. Positive coefficients of tropical nights (TR20), warm nights (TN90P) and warm days (TX90P), and the negative coefficient of cold days (TX10P) with time are significant at P<0.05. The increasing gradient of warm spell indicator (WSDI), the decreasing

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

    Science.gov (United States)

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

    2016-02-18

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

  3. Epiphytes as an Indicator of Climate Change in Hawaii

    Science.gov (United States)

    Kettwich, S. K.

    2013-12-01

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

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

    Science.gov (United States)

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

    2015-12-01

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

  5. A plant's perspective of extremes: terrestrial plant responses to changing climatic variability.

    Science.gov (United States)

    Reyer, Christopher P O; Leuzinger, Sebastian; Rammig, Anja; Wolf, Annett; Bartholomeus, Ruud P; Bonfante, Antonello; de Lorenzi, Francesca; Dury, Marie; Gloning, Philipp; Abou Jaoudé, Renée; Klein, Tamir; Kuster, Thomas M; Martins, Monica; Niedrist, Georg; Riccardi, Maria; Wohlfahrt, Georg; de Angelis, Paolo; de Dato, Giovanbattista; François, Louis; Menzel, Annette; Pereira, Marízia

    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, although potentially damaging. We note that plant water relations seem to be very vulnerable to extremes driven by changes in temperature and precipitation and that heat-waves 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.

  6. Climate-driven ground-level ozone extreme in the fall over the Southeast United States.

    Science.gov (United States)

    Zhang, Yuzhong; Wang, Yuhang

    2016-09-06

    Ground-level ozone is adverse to human and vegetation health. High ground-level ozone concentrations usually occur over the United States in the summer, often referred to as the ozone season. However, observed monthly mean ozone concentrations in the southeastern United States were higher in October than July in 2010. The October ozone average in 2010 reached that of July in the past three decades (1980-2010). Our analysis shows that this extreme October ozone in 2010 over the Southeast is due in part to a dry and warm weather condition, which enhances photochemical production, air stagnation, and fire emissions. Observational evidence and modeling analysis also indicate that another significant contributor is enhanced emissions of biogenic isoprene, a major ozone precursor, from water-stressed plants under a dry and warm condition. The latter finding is corroborated by recent laboratory and field studies. This climate-induced biogenic control also explains the puzzling fact that the two extremes of high October ozone both occurred in the 2000s when anthropogenic emissions were lower than the 1980s and 1990s, in contrast to the observed decreasing trend of July ozone in the region. The occurrences of a drying and warming fall, projected by climate models, will likely lead to more active photochemistry, enhanced biogenic isoprene and fire emissions, an extension of the ozone season from summer to fall, and an increase of secondary organic aerosols in the Southeast, posing challenges to regional air quality management.

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

    Science.gov (United States)

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

    2016-08-01

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

  8. Changing Temperature and Precipitation Extremes in Europe's Climate of the 20th Century

    NARCIS (Netherlands)

    Klein Tank, Albertus Maria Gerardus

    2004-01-01

    This thesis aims at increasing the knowledge on past changes in extremes through the analysis of historical records of observations at meteorological stations. The key question addressed is: How did the extremes of daily surface air temperature and precipitation change in Europe's climate of the

  9. Validation of EURO-CORDEX regional climate models in reproducing the variability of precipitation extremes in Romania

    Science.gov (United States)

    Dumitrescu, Alexandru; Busuioc, Aristita

    2016-04-01

    EURO-CORDEX is the European branch of the international CORDEX initiative that aims to provide improved regional climate change projections for Europe. The main objective of this paper is to document the performance of the individual models in reproducing the variability of precipitation extremes in Romania. Here three EURO-CORDEX regional climate models (RCMs) ensemble (scenario RCP4.5) are analysed and inter-compared: DMI-HIRHAM5, KNMI-RACMO2.2 and MPI-REMO. Compared to previous studies, when the RCM validation regarding the Romanian climate has mainly been made on mean state and at station scale, a more quantitative approach of precipitation extremes is proposed. In this respect, to have a more reliable comparison with observation, a high resolution daily precipitation gridded data set was used as observational reference (CLIMHYDEX project). The comparison between the RCM outputs and observed grid point values has been made by calculating three extremes precipitation indices, recommended by the Expert Team on Climate Change Detection Indices (ETCCDI), for the 1976-2005 period: R10MM, annual count of days when precipitation ≥10mm; RX5DAY, annual maximum 5-day precipitation and R95P%, precipitation fraction of annual total precipitation due to daily precipitation > 95th percentile. The RCMs capability to reproduce the mean state for these variables, as well as the main modes of their spatial variability (given by the first three EOF patterns), are analysed. The investigation confirms the ability of RCMs to simulate the main features of the precipitation extreme variability over Romania, but some deficiencies in reproducing of their regional characteristics were found (for example, overestimation of the mea state, especially over the extra Carpathian regions). This work has been realised within the research project "Changes in climate extremes and associated impact in hydrological events in Romania" (CLIMHYDEX), code PN II-ID-2011-2-0073, financed by the Romanian

  10. Assessment of future extreme climate events over the Porto wine Region

    Science.gov (United States)

    Viceto, Carolina; Cardoso, Susana; Marta-Almeida, Martinho; Gorodetskaya, Irina; Rocha, Alfredo

    2017-04-01

    to be produced (Porto and Douro wine), while climate variability affects the annual productivity and quality of the grape harvest. Our study investigates changes in the extreme climate events in the future model runs, through a set of climate change indicators defined by the WRCP's Expert Team in Climate Change Detection and Indices, which uses variables such as daily maximum and minimum temperatures and precipitation amounts. Furthermore, we explore heat waves and their properties (duration, intensity and recovery factor). The analysis shows an increase of the mean temperature in the DDR higher than 2°C by the mid-21st century and 4.5°C by the end of the century, relatively to the reference period. Moreover, we found a major predisposition towards higher values of minimum and maximum daily temperatures and a decrease in the total precipitation during both future periods. These preliminary results indicate increased climatic stress on the DDR wine production and increased vulnerability of the wine varieties in this region.

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

    Science.gov (United States)

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

    2017-02-01

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

  12. Adaptation to climate extremes in developing countries : the role of education

    OpenAIRE

    Blankespoor, Brian; Dasgupta, Susmita; Laplante, Benoit; Wheeler, David

    2010-01-01

    Global climate models predict a rise in extreme weather in the next century. To better understand future interactions among adaptation costs, socioeconomic development, and climate change in developing countries, observed losses of life from floods and droughts during 1960-2003 are modeled using three determinants: weather events, income per capita, and female education. The analysis revea...

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

    Science.gov (United States)

    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.

  14. Climate change impact assessment of extreme precipitation on urban flash floods – case study, Aarhus, Denmark

    DEFF Research Database (Denmark)

    Madsen, Henrik; Sunyer Pinya, Maria Antonia; Rosbjerg, Dan

    Climate change is expected to cause more intense extreme rainfall events, which will have a severe impact on the risk of flash floods in urban areas. An assessment study was performed for the city of Aarhus, Denmark, analysing different methods of statistical downscaling of climate model projecti......Climate change is expected to cause more intense extreme rainfall events, which will have a severe impact on the risk of flash floods in urban areas. An assessment study was performed for the city of Aarhus, Denmark, analysing different methods of statistical downscaling of climate model...... considered. Urban flooding in Aarhus was simulated with a model that dynamically couples a hydraulic model of the drainage system and a 2D overland flow model. Scenarios representing current and future climate including uncertainties in the climate projections were analysed using synthetic design storms...

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

    Science.gov (United States)

    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.

  16. Land Cover Indicators for U.S. National Climate Assessments

    Science.gov (United States)

    Channan, S.; Thomson, A. M.; Collins, K. M.; Sexton, J. O.; Torrens, P.; Emanuel, W. R.

    2014-12-01

    Land is a critical resource for human habitat and for the vast majority of human activities. Many natural resources are derived from terrestrial ecosystems or otherwise extracted from the landscape. Terrestrial biodiversity depends on land attributes as do people's perceptions of the value of land, including its value for recreation or tourism. Furthermore, land surface properties and processes affect weather and climate, and land cover change and land management affect emissions of greenhouse gases. Thus, land cover with its close association with climate is so pervasive that a land cover indicator is of fundamental importance to U.S. national climate assessments and related research. Moderate resolution remote sensing products (MODIS) were used to provide systematic data on annual distributions of land cover over the period 2001-2012. Selected Landsat observations and data products further characterize land cover at higher resolution. Here we will present the prototype for a suite of land cover indicators including land cover maps as well as charts depicting attributes such as composition by land cover class, statistical indicators of landscape characteristics, and tabular data summaries indispensable for communicating the status and trends of U.S. land cover at national, regional and state levels.

  17. Behavioral and life history responses to extreme climatic conditions: Studies on a migratory songbird

    OpenAIRE

    2011-01-01

    Behavioral responses to environmental change are the mechanisms that allow for rapid phenotypic change preventing temporary or permanent damage and hence preventing reductions in fitness. Extreme climatic events are by definition rare, although they are predicted to increase in amplitude and frequency in the coming years. However, our current knowledge about behavioral responses to such extreme events is scarce. Here I analyze two examples of the effects of extreme weather events on behavior ...

  18. The Last Transition From Extreme Glacial to Extreme Interglacial Climate in NW Patagonia: Regional and Global Implications

    Science.gov (United States)

    Moreno, P. I.

    2004-12-01

    The study of interhemispheric climate linkages during and since the last ice age has benefited from the recent development of high-resolution ice core and marine records from the mid- and high latitudes of the Southern Hemisphere. Few paleoclimate records from terrestrial environments in these regions, however, have the temporal continuity, time resolution, and adequate chronologic control to allow a detailed examination of the timing, rates, direction, and phasing of climate change at millennial timescales. Stratigraphic, palynologic, and charcoal records from small, high-sediment accumulating lakes in the Chilean Lake District (41ºS) afford useful data for examining the interval between the LGM to the early Holocene (25-8 ka, ka=cal kyr BP). Millennial-scale changes in glacier extent and vegetation patterns within this interval match key events both in the Northern Hemisphere and Antarctic records, in particular the EPICA Dome C data, highlighting the role of an atmosphere-based conduit for the global propagation of abrupt climate changes. The onset of the last termination in NW Patagonia is marked by glacial collapse and the expansion of rainforest trees at 17.7 ka. An apparent antiphase relationship among the polar hemispheres between 17.7-14.7 ka, might reflect the hemispheric-scale effects of a quasi-total shut down of Atlantic Meridional Overturning circulation driven by Heinrich event 1. Extreme glacial and interglacial modes in the position/strength of the westerlies at multi-millennial timescales in the southern westerlies accompany important shifts in the abundance and composition of rainforest communities during the last termination and the early Holocene. At millennial timescales, this interval is characterised by successive warming pulses interrupted by a generalized reversal in trend with cooling events starting at 14.7 and 13.4 ka. Fires between 12.9-11.5 ka, i.e. Younger Dryas Chron (YDC), led to the expansion of opportunistic rainforest species

  19. Assessing future climatic changes of rainfall extremes at small spatio-temporal scales

    DEFF Research Database (Denmark)

    Gregersen, Ida Bülow; Sørup, Hjalte Jomo Danielsen; Madsen, Henrik;

    2013-01-01

    in relation to urban flooding. The present study focuses on high-resolution regional climate model (RCM) skill in simulating sub-daily rainfall extremes. Temporal and spatial characteristics of output from three different RCM simulations with 25 km resolution are compared to point rainfall extremes estimated......Climate change is expected to influence the occurrence and magnitude of rainfall extremes and hence the flood risks in cities. Major impacts of an increased pluvial flood risk are expected to occur at hourly and sub-hourly resolutions. This makes convective storms the dominant rainfall type...

  20. Impacts of Climate Change on Rainfall Extremes and Urban Drainage Systems

    DEFF Research Database (Denmark)

    Willems, P.; Olsson, J.; Arnbjerg-Nielsen, Karsten;

    Impacts of Climate Change on Rainfall Extremes and Urban Drainage Systems provides a state-of-the-art overview of existing methodologies and relevant results related to the assessment of the climate change impacts on urban rainfall extremes as well as on urban hydrology and hydraulics....... This overview focuses mainly on several difficulties and limitations regarding the current methods and discusses various issues and challenges facing the research community in dealing with the climate change impact assessment and adaptation for urban drainage infrastructure design and management....

  1. Regional projection of climate impact indices over the Mediterranean region

    Science.gov (United States)

    Casanueva, Ana; Frías, M.; Dolores; Herrera, Sixto; Bedia, Joaquín; San Martín, Daniel; Gutiérrez, José Manuel; Zaninovic, Ksenija

    2014-05-01

    Climate Impact Indices (CIIs) are being increasingly used in different socioeconomic sectors to transfer information about climate change impacts and risks to stakeholders. CIIs are typically based on different weather variables such as temperature, wind speed, precipitation or humidity and comprise, in a single index, the relevant meteorological information for the particular impact sector (in this study wildfires and tourism). This dependence on several climate variables poses important limitations to the application of statistical downscaling techniques, since physical consistency among variables is required in most cases to obtain reliable local projections. The present study assesses the suitability of the "direct" downscaling approach, in which the downscaling method is directly applied to the CII. In particular, for illustrative purposes, we consider two popular indices used in the wildfire and tourism sectors, the Fire Weather Index (FWI) and the Physiological Equivalent Temperature (PET), respectively. As an example, two case studies are analysed over two representative Mediterranean regions of interest for the EU CLIM-RUN project: continental Spain for the FWI and Croatia for the PET. Results obtained with this "direct" downscaling approach are similar to those found from the application of the statistical downscaling to the individual meteorological drivers prior to the index calculation ("component" downscaling) thus, a wider range of statistical downscaling methods could be used. As an illustration, future changes in both indices are projected by applying two direct statistical downscaling methods, analogs and linear regression, to the ECHAM5 model. Larger differences were found between the two direct statistical downscaling approaches than between the direct and the component approaches with a single downscaling method. While these examples focus on particular indices and Mediterranean regions of interest for CLIM-RUN stakeholders, the same study

  2. Characteristics of sub-daily precipitation extremes in observed data and regional climate model simulations

    Science.gov (United States)

    Beranová, Romana; Kyselý, Jan; Hanel, Martin

    2017-03-01

    The study compares characteristics of observed sub-daily precipitation extremes in the Czech Republic with those simulated by Hadley Centre Regional Model version 3 (HadRM3) and Rossby Centre Regional Atmospheric Model version 4 (RCA4) regional climate models (RCMs) driven by reanalyses and examines diurnal cycles of hourly precipitation and their dependence on intensity and surface temperature. The observed warm-season (May-September) maxima of short-duration (1, 2 and 3 h) amounts show one diurnal peak in the afternoon, which is simulated reasonably well by RCA4, although the peak occurs too early in the model. HadRM3 provides an unrealistic diurnal cycle with a nighttime peak and an afternoon minimum coinciding with the observed maximum for all three ensemble members, which suggests that convection is not captured realistically. Distorted relationships of the diurnal cycles of hourly precipitation to daily maximum temperature in HadRM3 further evidence that underlying physical mechanisms are misrepresented in this RCM. Goodness-of-fit tests indicate that generalised extreme value distribution is an applicable model for both observed and RCM-simulated precipitation maxima. However, the RCMs are not able to capture the range of the shape parameter estimates of distributions of short-duration precipitation maxima realistically, leading to either too many (nearly all for HadRM3) or too few (RCA4) grid boxes in which the shape parameter corresponds to a heavy tail. This means that the distributions of maxima of sub-daily amounts are distorted in the RCM-simulated data and do not match reality well. Therefore, projected changes of sub-daily precipitation extremes in climate change scenarios based on RCMs not resolving convection need to be interpreted with caution.

  3. Identifying hydro-meteorological events from precipitation extremes indices and other sources over northern Namibia, Cuvelai Basin

    Directory of Open Access Journals (Sweden)

    Frans C. Persendt

    2015-02-01

    Full Text Available Worldwide, more than 40% of all natural hazards and about half of all deaths are the result of flood disasters. In northern Namibia flood disasters have increased dramatically over the past half-century, along with associated economic losses and fatalities. There is a growing concern to identify these extreme precipitation events that result in many hydro-meteorological disasters. This study presents an up to date and broad analysis of the trends of hydrometeorological events using extreme daily precipitation indices, daily precipitation data from the Grootfontein rainfall station (1917–present, regionally averaged climatologies from the gauged gridded Climate Research Unit (CRU product, archived disasters by global disaster databases, published disaster events in literature as well as events listed by Mendelsohn, Jarvis and Robertson (2013 for the data-sparse Cuvelai river basin (CRB. The listed events that have many missing data gaps were used to reference and validate results obtained from other sources in this study. A suite of ten climate change extreme precipitation indices derived from daily precipitation data (Grootfontein rainfall station, were calculated and analysed. The results in this study highlighted years that had major hydro-meteorological events during periods where no data are available. Furthermore, the results underlined decrease in both the annual precipitation as well as the annual total wet days of precipitation, whilst it found increases in the longest annual dry spell indicating more extreme dry seasons. These findings can help to improve flood risk management policies by providing timely information on historic hydro-meteorological hazard events that are essential for early warning and forecasting.

  4. Projection of extreme precipitation in the context of climate change in Huang-Huai-Hai region, China

    Indian Academy of Sciences (India)

    Jun Yin; Denghua Yan; Zhiyong Yang; Zhe Yuan; Yong Yuan; Cheng Zhang

    2016-03-01

    Based on the national precipitation dataset (0.5$^{\\circ }$ × 0.5$^{\\circ }$) 1961–2011, published by the National Meteorological Information Center of China and the five Global Climate Models provided by ISI-MIP, annual maximum precipitation for 1 day, 3 days and 7 days could be calculated. Extreme precipitation was fitted via Generalized Extreme Value (GEV) distribution to explore the changes of extreme precipitation with the return period of 20 years and 50 years during 1961–2000 and 2001–2050. Based on this, extreme precipitation projection in Huang-Huai-Hai region was done. The results showed that the five Global Climate Models could simulate the statistical features of extreme precipitation quite well, in which IPSL-CM5A-LR has the highest precision. Simulation of IPSL-CM5A-LR indicates that precipitation with the return period of 20 years and 50 years in the middle reaches of the Yellow River, middle and lower reaches of Huaihe River and plain area of the southern Haihe River will increase considerably in the future. Extreme precipitation in some of the places will even increase by more than 30%, which means that these places will face larger flood risk and their capacity to respond to flood disasters should be improved.

  5. Behavioral and life history responses to extreme climatic conditions: Studies on a migratory songbird

    Institute of Scientific and Technical Information of China (English)

    A. P. Mφller

    2011-01-01

    Behavioral responses to environmental change are the mechanisms that allow for rapid phenotypic change preventing temporary or permanent damage and hence preventing reductions in fitness. Extreme climatic events are by definition rare, although they are predicted to increase in amplitude and frequency in the coming years. However, our current knowledge about behavioral responses to such extreme events is scarce. Here I analyze two examples of the effects of extreme weather events on behavior and life history: (1) A comparison of behavior and life history during extremely warm and extremely cold years relative to normal years; and (2) a comparison of behavior before and after the extremely early snowfall in fall 1974 when numerous birds died in the Alps during September-October. Behavioral and life history responses of barn swallows Hirundo rustica to extremely cold and extremely warm years were positively correlated, with particularly large effect sizes in cold years. Extreme mortality in barn swallows during fall migration 1974 in the Alps eliminated more than 40% of the breeding population across large areas in Central and Northern Europe, and this affected first arrival date, changes in timing and extent of reproduction and changes in degree of breeding sociality supposedly as a consequence of correlated responses to selection. Finally, I provide directions for research that will allow us to better understand behavior and life history changes in response to extreme climate change [Current Zoology 57 (3): 351-362,2011].

  6. Behavioral and life history responses to extreme climatic conditions: Studies on a migratory songbird

    Directory of Open Access Journals (Sweden)

    A. P. Møller

    2011-06-01

    Full Text Available Behavioral responses to environmental change are the mechanisms that allow for rapid phenotypic change preventing temporary or permanent damage and hence preventing reductions in fitness. Extreme climatic events are by definition rare, although they are predicted to increase in amplitude and frequency in the coming years. However, our current knowledge about behavioral responses to such extreme events is scarce. Here I analyze two examples of the effects of extreme weather events on behavior and life history: (1 A comparison of behavior and life history during extremely warm and extremely cold years relative to normal years; and (2 a comparison of behavior before and after the extremely early snowfall in fall 1974 when numerous birds died in the Alps during September-October. Behavioral and life history responses of barn swallows Hirundo rustica to extremely cold and extremely warm years were positively correlated, with particularly large effect sizes in cold years. Extreme mortality in barn swallows during fall migration 1974 in the Alps eliminated more than 40% of the breeding population across large areas in Central and Northern Europe, and this affected first arrival date, changes in timing and extent of reproduction and changes in degree of breeding sociality supposedly as a consequence of correlated responses to selection. Finally, I provide directions for research that will allow us to better understand behavior and life history changes in response to extreme climate change [Current Zoology 57 (3: 351–362, 2011].

  7. Using NASA Earth Science Datasets for National Climate Assessment Indicators: Urban Impacts of Heat Waves Associated with Climate Change

    Science.gov (United States)

    Sadoff, N.; Weber, S.; Zell, E. R.; de Sherbinin, A. M.

    2014-12-01

    Climate-induced heat waves have been increasing globally in the past 5-10 years and are projected to continue increasing throughout the 21st century. In urban areas, heat waves are exacerbated by the non-climate stressor of urban heat islands (UHIs). The vulnerability of a city's population to heat waves reflects exposure to extreme heat events, sensitivity of the population to impacts, such as adverse health effects, and adaptive capacity to prepare for and respond to heat waves. Socially and economically vulnerable populations are especially at risk to the impacts of heat waves, due to increasing energy costs, air pollution, and heat-related illness and mortality. NASA earth science datasets, combined with socioeconomic data, can be used to create indicators that characterize vulnerability to urban heat events and address the effectiveness of adaptation measures designed to reduce local temperatures. The indicator development process should include engagement from local stakeholders and end users from the onset to ensure local relevance and, ultimately, indicator uptake and sustainability. This presentation will explore the process of working with urban stakeholders in Philadelphia to develop a set of policy-relevant, interdisciplinary vulnerability indicators focused on extreme heat events in urban areas. Ambient and land surface temperature, land cover classifications, NDVI, and US Census data are used to create a basket of indicators that reflect urban heat wave duration and intensity, UHI exposure, socioeconomic vulnerability, and adaptation effectiveness. These indicators can be assessed at the city level and also comparatively among different parts of a city to help quantify and track heat wave impacts on vulnerable populations and the effectiveness of adaptation measures.

  8. Extreme winds and sea-surges in climate models

    NARCIS (Netherlands)

    Brink, H.W. (Hendrik Willem) van den

    2005-01-01

    This thesis deals with the problem of how to estimate values of meteorological parameters that correspond to return periods that are considerably longer than the length of the observational data sets. The problem is approached by considering the output of weather-and climate models as pseudo-observ

  9. Extreme climatic events shape arid and semiarid ecosystems

    NARCIS (Netherlands)

    Holmgren, M.; Stapp, P.; Dickman, C.; Gracia, C.; Graham, S.

    2006-01-01

    Climatic changes associated with the El Nino Southern Oscillation (ENSO) can have a dramatic impact on terrestrial ecosystems worldwide, but especially on arid and semiarid systems, where productivity is strongly limited by precipitation. Nearly two decades of research, including both short-term exp

  10. The effect of future reduction in aerosol emissions on climate extremes in China

    Science.gov (United States)

    Wang, Zhili; Lin, Lei; Yang, Meilin; Xu, Yangyang

    2016-11-01

    This study investigates the effect of reduced aerosol emissions on projected temperature and precipitation extremes in China during 2031-2050 and 2081-2100 relative to present-day conditions using the daily data output from the Community Earth System Model ensemble simulations under the Representative Concentration Pathway (RCP) 8.5 with an applied aerosol reduction and RCP8.5 with fixed 2005 aerosol emissions (RCP8.5_FixA) scenarios. The reduced aerosol emissions of RCP8.5 magnify the warming effect due to greenhouse gases (GHG) and lead to significant increases in temperature extremes, such as the maximum of daily maximum temperature (TXx), minimum of daily minimum temperature (TNn), and tropical nights (TR), and precipitation extremes, such as the maximum 5-day precipitation amount, number of heavy precipitation days, and annual total precipitation from days ˃95th percentile, in China. The projected TXx, TNn, and TR averaged over China increase by 1.2 ± 0.2 °C (4.4 ± 0.2 °C), 1.3 ± 0.2 °C (4.8 ± 0.2 °C), and 8.2 ± 1.2 (30.9 ± 1.4) days, respectively, during 2031-2050 (2081-2100) under the RCP8.5_FixA scenario, whereas the corresponding values are 1.6 ± 0.1 °C (5.3 ± 0.2 °C), 1.8 ± 0.2 °C (5.6 ± 0.2 °C), and 11.9 ± 0.9 (38.4 ± 1.0) days under the RCP8.5 scenario. Nationally averaged increases in all of those extreme precipitation indices above due to the aerosol reduction account for more than 30 % of the extreme precipitation increases under the RCP8.5 scenario. Moreover, the aerosol reduction leads to decreases in frost days and consecutive dry days averaged over China. There are great regional differences in changes of climate extremes caused by the aerosol reduction. When normalized by global mean surface temperature changes, aerosols have larger effects on temperature and precipitation extremes over China than GHG.

  11. WEATHER AND CLIMATE EXTREMES IN LIGHT OF THE IPCC SREX (2011 AND BEYOND

    Directory of Open Access Journals (Sweden)

    JÁNOS MIKA

    2012-03-01

    Full Text Available Weather and climate extremes in light of the IPCC SREX (2011 and beyond. The recent IPCC Special Report (IPCC SREX, 2011 provides a comprehensive overview of meteorological (i.e. weather and climate extremes and their various aspects. The present paper reflects the core concepts of the Report, clarifying the relations of the natural and anthropogenic factors causing meteorological extremes, as well, as condition determining the risks and general ways of response by the society. The paper can only add some recent statistics to this scheme on various aspects of meteorological and non-meteorological reasons of natural disasters. The paper argues, however, the still unclear definition of the extremes and their classification as weather and climate extremes. We also dedicate a sub-Section to the statistical and physical considerations on how the extremes may change parallel to the global warming. Another sub-Section refers to further difficulties that hamper the empirical establishment of the trends in the meteorological extremes. Finally we overview the IPCC AR4 (2007 conclusions on some meteorological extremes, since the detailed Chapters of the IPCC SREX (2011 Report were not available by the time of writing the paper, but from its SPM no difference in the statements and even its uncertainties can be established since the AR4.

  12. Improving pan-european hydrological simulation of extreme events through statistical bias correction of RCM-driven climate simulations

    Directory of Open Access Journals (Sweden)

    R. Rojas

    2011-04-01

    Full Text Available In this work we asses the benefits of removing bias in climate forcing data used for hydrological climate change impact assessment at pan-European scale, with emphasis on floods. Climate simulations from the HIRHAM5-ECHAM5 model driven by the SRES-A1B emission scenario are corrected for bias using a histogram equalization method. As predictand for the bias correction we employ gridded interpolated observations of precipitation, average, minimum, and maximum temperature from the E-OBS data set. Bias removal transfer functions are derived for the control period 1961–1990. These are subsequently used to correct the climate simulations for the control period, and, under the assumption of a stationary error model, for the future time window 2071–2100. Validation against E-OBS climatology in the control period shows that the correction method performs successfully in removing bias in average and extreme statistics relevant for flood simulation over the majority of the European domain in all seasons. This translates into considerably improved simulations with the hydrological model of observed average and extreme river discharges at a majority of 554 validation river stations across Europe. Probabilities of extreme events derived employing extreme value techniques are also more closely reproduced. Results indicate that projections of future flood hazard in Europe based on uncorrected climate simulations, both in terms of their magnitude and recurrence interval, are likely subject to large errors. Notwithstanding the inherent limitations of the large-scale approach used herein, this study strongly advocates the removal of bias in climate simulations prior to their use in hydrological impact assessment.

  13. Improving pan-European hydrological simulation of extreme events through statistical bias correction of RCM-driven climate simulations

    Directory of Open Access Journals (Sweden)

    R. Rojas

    2011-08-01

    Full Text Available In this work we asses the benefits of removing bias in climate forcing data used for hydrological climate change impact assessment at pan-European scale, with emphasis on floods. Climate simulations from the HIRHAM5-ECHAM5 model driven by the SRES-A1B emission scenario are corrected for bias using a histogram equalization method. As target for the bias correction we employ gridded interpolated observations of precipitation, average, minimum, and maximum temperature from the E-OBS data set. Bias removal transfer functions are derived for the control period 1961–1990. These are subsequently used to correct the climate simulations for the control period, and, under the assumption of a stationary error model, for the future time window 2071–2100. Validation against E-OBS climatology in the control period shows that the correction method performs successfully in removing bias in average and extreme statistics relevant for flood simulation over the majority of the European domain in all seasons. This translates into considerably improved simulations with the hydrological model of observed average and extreme river discharges at a majority of 554 validation river stations across Europe. Probabilities of extreme events derived employing extreme value techniques are also more closely reproduced. Results indicate that projections of future flood hazard in Europe based on uncorrected climate simulations, both in terms of their magnitude and recurrence interval, are likely subject to large errors. Notwithstanding the inherent limitations of the large-scale approach used herein, this study strongly advocates the removal of bias in climate simulations prior to their use in hydrological impact assessment.

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    Detailed understanding of a possible decoupling between climatic drivers of plant productivity and the response of ecosystems vegetation is required. We compared trends in six NDVI metrics (1982-2010) derived from the GIMMS3g dataset with modelled biomass productivity and assessed uncertainty...... an increasing difference between trends in climatic drivers and observed NDVI for large parts of the globe. Our findings suggest that future scenarios must consider impacts of constraints on plant growth such as extremes in weather and nutrient availability to predict changes in NPP and CO2 sequestration...... in trend estimates. Annual total biomass weight (TBW) was calculated with the LINPAC model. Trends were determined using a simple linear regression, a Thiel-Sen medium slope and a piecewise regression (PWR) with two segments. Values of NDVI metrics were related to Net Primary Production (MODIS...

  15. Seasonal Prediction of Hydro-Climatic Extremes in the Greater Horn of Africa Under Evolving Climate Conditions to Support Adaptation Strategies

    Science.gov (United States)

    Tadesse, T.; Zaitchik, B. F.; Habib, S.; Funk, C. C.; Senay, G. B.; Dinku, T.; Policelli, F. S.; Block, P.; Baigorria, G. A.; Beyene, S.; Wardlow, B.; Hayes, M. J.

    2014-12-01

    , meteorological, and hydrologic drought and flood monitoring products (or indicators) that can enhance the preparedness for extreme climate events and climate change adaptation and mitigation strategies in the GHA. Even though this project is in its first year, the preliminary results and future plans to carry out the objectives will be presented.

  16. Extreme Climate Variations from Milankovitch-like Eccentricity Oscillations in Extrasolar Planetary Systems

    CERN Document Server

    Spiegel, David S

    2010-01-01

    Although our solar system features predominantly circular orbits, the exoplanets discovered so far indicate that this is the exception rather than the rule. This could have crucial consequences for exoplanet climates, both because eccentric terrestrial exoplanets could have extreme seasonal variation, and because giant planets on eccentric orbits could excite Milankovitch-like variations of a potentially habitable terrestrial planet,\\"A\\^os eccentricity, on timescales of thousands-to-millions of years. A particularly interesting implication concerns the fact that the Earth is thought to have gone through at least one globally frozen, "snowball" state in the last billion years that it presumably exited after several million years of buildup of greenhouse gases when the ice-cover shut off the carbonate-silicate cycle. Water-rich extrasolar terrestrial planets with the capacity to host life might be at risk of falling into similar snowball states. Here we show that if a terrestrial planet has a giant companion o...

  17. A spatial assessment framework for evaluating flood risk under extreme climates.

    Science.gov (United States)

    Chen, Yun; Liu, Rui; Barrett, Damian; Gao, Lei; Zhou, Mingwei; Renzullo, Luigi; Emelyanova, Irina

    2015-12-15

    Australian coal mines have been facing a major challenge of increasing risk of flooding caused by intensive rainfall events in recent years. In light of growing climate change concerns and the predicted escalation of flooding, estimating flood inundation risk becomes essential for understanding sustainable mine water management in the Australian mining sector. This research develops a spatial multi-criteria decision making prototype for the evaluation of flooding risk at a regional scale using the Bowen Basin and its surroundings in Queensland as a case study. Spatial gridded data, including climate, hydrology, topography, vegetation and soils, were collected and processed in ArcGIS. Several indices were derived based on time series of observations and spatial modeling taking account of extreme rainfall, evapotranspiration, stream flow, potential soil water retention, elevation and slope generated from a digital elevation model (DEM), as well as drainage density and proximity extracted from a river network. These spatial indices were weighted using the analytical hierarchy process (AHP) and integrated in an AHP-based suitability assessment (AHP-SA) model under the spatial risk evaluation framework. A regional flooding risk map was delineated to represent likely impacts of criterion indices at different risk levels, which was verified using the maximum inundation extent detectable by a time series of remote sensing imagery. The result provides baseline information to help Bowen Basin coal mines identify and assess flooding risk when making adaptation strategies and implementing mitigation measures in future. The framework and methodology developed in this research offers the Australian mining industry, and social and environmental studies around the world, an effective way to produce reliable assessment on flood risk for managing uncertainty in water availability under climate change.

  18. Mountains as early warning indicators of climate change

    Science.gov (United States)

    Williams, M. W.

    2015-12-01

    The panoramic splendor and complexity of mountain environments have inspired and challenged humans for centuries. These areas have been variously perceived as physical structures to be conquered, as sites of spiritual inspiration, and as some of the last untamed natural places on Earth. In our time, the perception that "mountains are forever" may provide solace to those seeking stability in a rapidly changing world. However, changes in the hydrology and in the abundance and species composition of the native flora and fauna of mountain ecosystems are potential bellwethers of global change, because these systems have a propensity to amplify environmental changes within specific portions of this landscape. Mountain areas are thus sentinels of climate change. We are seeing effects today in case histories I present from the Himalaya's, Andes, Alps, and Rocky Mountains. Furthermore, these ecosystem changes are occurring in mountain areas before they occur in downstream ecosystems. Thus, mountains are early warning indicators of perturbations such as climate change. The sensitivity of mountain ecosystems begs for enhanced protection and worldwide protection. Our understanding of the processes that control mountain ecosystems—climate interactions, snowmelt runoff, biotic diversity, nutrient cycling—is much less developed compared to downstream ecosystems where human habitation and development has resulted in large investments in scientific knowledge to sustain health and agriculture. To address these deficiencies, I propose the formation of an international mountain research consortium.

  19. Global Wildfire Forecasts Using Large Scale Climate Indices

    Science.gov (United States)

    Shen, Huizhong; Tao, Shu

    2016-04-01

    Using weather readings, fire early warning can provided forecast 4-6 hour in advance to minimize fire loss. The benefit would be dramatically enhanced if relatively accurate long-term projection can be also provided. Here we present a novel method for predicting global fire season severity (FSS) at least three months in advance using multiple large-scale climate indices (CIs). The predictive ability is proven effective for various geographic locations and resolution. Globally, as well as in most continents, the El Niño Southern Oscillation (ENSO) is the dominant driving force controlling interannual FSS variability, whereas other CIs also play indispensable roles. We found that a moderate El Niño event is responsible for 465 (272-658 as interquartile range) Tg carbon release and an annual increase of 29,500 (24,500-34,800) deaths from inhalation exposure to air pollutants. Southeast Asia accounts for half of the deaths. Both intercorrelation and interaction of WPs and CIs are revealed, suggesting possible climate-induced modification of fire responses to weather conditions. Our models can benefit fire management in response to climate change.

  20. Climate indices, rainfall onset and retreat, and malaria in Nigeri

    Directory of Open Access Journals (Sweden)

    A.J. Thomso

    2010-12-01

    Full Text Available Background & objectives: Rainfall in western sub-Saharan Africa is related to seasonal shifts ofthe Inter-tropical Convergence Zone, which moves northward early in the year, retreating in thesecond half of the year. The objective of the present study was to determine significant relationshipsbetween onset and retreat timing and climate indices. The relationship between timing and malariacase reporting was then evaluated.Methods: Relationships between published rainfall onset and retreat dates for Nigeria from 1971–2000 were evaluated in relation to pairs of climate indices using response surface analysis. Graphicalrepresentation of the response surface in relation to the underlying data was used to identify instancesof overfitting. Association of onset and retreat timing with published case reporting records wasevaluated using graphical and correlation analysis.Results: Onset timing and rate of advance were related to ENSO (El Niño-Southern Oscillation,in combination with the Northern Annular Mode (NAM, while retreat timing was related to NAO(North Atlantic Oscillation, in combination with the East Pacific (EP or West Pacific (WPindex, depending on location. Later onset was associated with faster northward progression ofonset. Retreat date at Kano, the most northerly of the study locations, increased over the period1990–2000, with higher case reporting for Nigeria as a whole being associated with the last threeyears of that period.Interpretation & conclusion: Rainfall retreat occurs much faster than onset, with onset and retreattiming and rate of onset advance being related to combinations of climate indices rather than to asingle index. Threshold for determining a “rainy” day would influence results. The increase innational case reporting with delayed retreat at Kano may be related to the extension of the shorttransmission period in the north.

  1. Diagnostic indicators for integrated assessment models of climate policy

    Energy Technology Data Exchange (ETDEWEB)

    Kriegler, Elmar; Petermann, Nils; Krey, Volker; Schwanitz, Jana; Luderer, Gunnar; Ashina, Shuichi; Bosetti, Valentina; Eom, Jiyong; Kitous, Alban; Mejean, Aurelie; Paroussos, Leonidas; Sano, Fuminori; Turton, Hal; Wilson, Charlie; Van Vuuren, Detlef

    2015-01-01

    Integrated assessments of how climate policy interacts with energy-economic systems can be performed by a variety of models with different functional structures. This article proposes a diagnostic scheme that can be applied to a wide range of integrated assessment models to classify differences among models based on their carbon price responses. Model diagnostics can uncover patterns and provide insights into why, under a given scenario, certain types of models behave in observed ways. Such insights are informative since model behavior can have a significant impact on projections of climate change mitigation costs and other policy-relevant information. The authors propose diagnostic indicators to characterize model responses to carbon price signals and test these in a diagnostic study with 11 global models. Indicators describe the magnitude of emission abatement and the associated costs relative to a harmonized baseline, the relative changes in carbon intensity and energy intensity and the extent of transformation in the energy system. This study shows a correlation among indicators suggesting that models can be classified into groups based on common patterns of behavior in response to carbon pricing. Such a classification can help to more easily explain variations among policy-relevant model results.

  2. Predicting Ice Sheet and Climate Evolution at Extreme Scales

    Energy Technology Data Exchange (ETDEWEB)

    Heimbach, Patrick [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    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

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

    DEFF Research Database (Denmark)

    Rosbjerg, Dan

    2017-01-01

    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......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....... 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...

  4. Multi-model projection of July-August climate extreme changes over China under CO2 doubling. Part I: Precipitation

    Science.gov (United States)

    Li, Hongmei; Feng, Lei; Zhou, Tianjun

    2011-03-01

    Potential changes in precipitation extremes in July-August over China in response to CO2 doubling are analyzed based on the output of 24 coupled climate models from the Twentieth-Century Climate in Coupled Models (20C3M) experiment and the 1% per year CO2 increase experiment (to doubling) (1pctto2x) of phase 3 of the Coupled Model Inter-comparison Project (CMIP3). Evaluation of the models' performance in simulating the mean state shows that the majority of models fairly reproduce the broad spatial pattern of observed precipitation. However, all the models underestimate extreme precipitation by ˜50%. The spread among the models over the Tibetan Plateau is ˜2-3 times larger than that over the other areas. Models with higher resolution generally perform better than those with lower resolutions in terms of spatial pattern and precipitation amount. Under the 1pctto2x scenario, the ratio between the absolute value of MME extreme precipitation change and model spread is larger than that of total precipitation, indicating a relatively robust change of extremes. The change of extreme precipitation is more homogeneous than the total precipitation. Analysis on the output of Geophysical Fluid Dynamics Laboratory coupled climate model version 2.1 (GFDL-CM2.1) indicates that the spatially consistent increase of surface temperature and water vapor content contribute to the large increase of extreme precipitation over contiguous China, which follows the Clausius-Clapeyron relationship. Whereas, the meridionally tri-polar pattern of mean precipitation change over eastern China is dominated by the change of water vapor convergence, which is determined by the response of monsoon circulation to global warming.

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

    Science.gov (United States)

    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.

  6. Identifying climate analogues for precipitation extremes for Denmark based on RCM simulations from the ENSEMBLES database.

    Science.gov (United States)

    Arnbjerg-Nielsen, K; Funder, S G; Madsen, H

    2015-01-01

    Climate analogues, also denoted Space-For-Time, may be used to identify regions where the present climatic conditions resemble conditions of a past or future state of another location or region based on robust climate variable statistics in combination with projections of how these statistics change over time. The study focuses on assessing climate analogues for Denmark based on current climate data set (E-OBS) observations as well as the ENSEMBLES database of future climates with the aim of projecting future precipitation extremes. The local present precipitation extremes are assessed by means of intensity-duration-frequency curves for urban drainage design for the relevant locations being France, the Netherlands, Belgium, Germany, the United Kingdom, and Denmark. Based on this approach projected increases of extreme precipitation by 2100 of 9 and 21% are expected for 2 and 10 year return periods, respectively. The results should be interpreted with caution as the best region to represent future conditions for Denmark is the coastal areas of Northern France, for which only little information is available with respect to present precipitation extremes.

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

    Science.gov (United States)

    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.

  8. Impact of Climate Change on Five Major Crop Fungal Diseases: Building Climatic Indicators of Infection Risk

    Science.gov (United States)

    Launay, M.; Caubel, J.; Bourgeois, G.; Huard, F.; Garcia de Cortazar-Atauri, I.

    2013-12-01

    The climate change will modify the severity and occurrence of fungal crop diseases, as the bioclimatic niches of pathogens will shift according to temperature and rainfall patterns evolution. Therefore it becomes necessary to integrate fungal disease pressure assessment into evaluation tools of crop suitability at the regional level. The aim of this study was to build two climatic indicators, the Average Infection Efficiency (AIE) and the Number of Infection Days (NID), quantifying the potential effect of climate on infection intensity and occurrence. A simple and continuous function was developed to calculate them, which is easy to parameterize from experimental measurements, usable on large spatial scales and adaptable to various pathogens. The evolution of those climatic indicators was then studied for five major fungal crop diseases in Northern France, the phoma of oilseed rape, the potato late blight, the downy mildew of grape, the leaf rust of wheat and the net blotch of barley. These indicators were applied on a multisite analysis in Northern France. They were calculated during the crop cycle when the host plant is able to be infected, over the period between 1970 and 2100 for the balanced scenario of climate change A1B. In late spring and summer, higher temperatures combined with lower humidity reduced the risk of infection of potato late blight and downy mildew of grape. In autumn and spring the balance between warmer temperatures and lower humidity determined the risk of infection on oilseed rape and cereals: increased risk in late autumn and early spring, and decreased risk in early autumn and mid-spring when low humidity becomes limiting. This statement highlighted the need for using between year scale for a relevant analysis of climate change impact on infection risk. The indicators we developed are thus useful for land management at regional scale and medium term, in particular for stakeholders who need decision support tools through which they could

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    2014-01-01

    In support of the National Climate Assessment (NCA) program, satellite Lightning Imaging Sensor (LIS) data is used to estimate lightning nitrogen oxides (LNOx) production over the southern portion of the conterminous US. The total energy of each flash is estimated by analyzing the LIS optical event data associated with each flash (i.e., event radiance, event footprint area, and derivable event range). The LIS detects an extremely small fraction of the total flash energy; this fraction is assumed to be constant apart from the variability associated with the flash optical energy detected across the narrow (0.909 nm) LIS band. The estimate of total energy from each flash is converted to moles of LNOx production by assuming a chemical yield of 10(17) molecules Joule(-1). The LIS-inferred variable LNOx production from each flash is summed to obtain total LNOx production, and then appropriately enhanced to account for LIS detection efficiency and LIS view time. Annual geographical plots and time series of LNOx production are provided for a 16 year period (1998-2013).

  11. Assessing the potential impacts of climate change on return periods of hydrological extremes in the Illinois River watershed of the Midwestern United States

    Science.gov (United States)

    Chien, H.; Yeh, P. J. F.; Knouft, J.

    2014-12-01

    As the Earth's climate is predicted to change significantly in terms of warmer temperature and higher precipitation extremes during this century due to the increased combustion of fossil fuels, accurate estimations of the frequencies of future hydrological extremes are important to understanding the potential impacts of changes in climate on water resources management, particularly in accessing flood risk. The goal of this study is to use the Soil and Water Assessment Tool (SWAT), a distributed landscape-scale hydrological model, to predict current streamflow and the potential impacts of climate change on future stream flows in the Illinois River watershed in the Midwestern United States. Subsequently Gumbel distribution (Extreme Value Type Ⅰ) is fitted to the annual maxima simulated streamflow to derive a number of return periods of future hydrological extremes. The question in this study is: How do the return periods of future hydrological extremes change under future climate change scenarios and what factors cause the change? Daily simulated future streamflow from 2046-2065 and 2081-2100 are simulated using SWAT model based on nine separate downscaled global climate models (GCM) with three emissions scenarios. SWAT model predictions generally indicate that annual streamflow will likely decrease due to warmer temperatures. Based on the simulated daily streamflow, probability models for annual maxima flows frequency analysis are developed using Gumbel distribution and the values of hydrological extremes for different return periods including 50, 100, 200, 500, 1000 years are derived. The change of return periods of hydrological extremes and the implications will be discussed.

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

    Directory of Open Access Journals (Sweden)

    Mirjana Čižmešija

    2010-12-01

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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    McCormick, Niall; Gobron, Nadine

    2016-08-01

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

  16. Optimal adaptation to extreme rainfalls under climate change

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  19. The impact of ENSO and the NAO on extreme winter precipitation in North America in observations and regional climate models

    Science.gov (United States)

    Whan, Kirien; Zwiers, Francis

    2017-03-01

    The relationship between winter precipitation in North America and indices of the North Atlantic Oscillation (NAO) and El Niño-Southern Oscillation (ENSO) is evaluated using non-stationary generalized extreme value distributions with the indices as covariates. Both covariates have a statistically significant influence on precipitation that is well simulated by two regional climate models (RCMs), CanRCM4 and CRCM5. The observed influence of the NAO on extreme precipitation is largest in eastern North America, with the likelihood of a negative phase extreme rainfall event decreased in the north and increased in the south under the positive phase of the NAO. This pattern is generally well simulated by the RCMs although there are some differences in the extent of influence, particularly south of the Great Lakes. A La Niña-magnitude extreme event is more likely to occur under El Niño conditions in California and the southern United States, and less likely in most of Canada and a region south of the Great Lakes. This broad pattern is also simulated well by the RCMs but they do not capture the increased likelihood in California. In some places the extreme precipitation response in the RCMs to external forcing from a covariate is of the opposite sign, despite use of the same lateral boundary conditions and dynamical core. This demonstrates the importance of model physics for teleconnections to extreme precipitation.

  20. The impact of ENSO and the NAO on extreme winter precipitation in North America in observations and regional climate models

    Science.gov (United States)

    Whan, Kirien; Zwiers, Francis

    2016-05-01

    The relationship between winter precipitation in North America and indices of the North Atlantic Oscillation (NAO) and El Niño-Southern Oscillation (ENSO) is evaluated using non-stationary generalized extreme value distributions with the indices as covariates. Both covariates have a statistically significant influence on precipitation that is well simulated by two regional climate models (RCMs), CanRCM4 and CRCM5. The observed influence of the NAO on extreme precipitation is largest in eastern North America, with the likelihood of a negative phase extreme rainfall event decreased in the north and increased in the south under the positive phase of the NAO. This pattern is generally well simulated by the RCMs although there are some differences in the extent of influence, particularly south of the Great Lakes. A La Niña-magnitude extreme event is more likely to occur under El Niño conditions in California and the southern United States, and less likely in most of Canada and a region south of the Great Lakes. This broad pattern is also simulated well by the RCMs but they do not capture the increased likelihood in California. In some places the extreme precipitation response in the RCMs to external forcing from a covariate is of the opposite sign, despite use of the same lateral boundary conditions and dynamical core. This demonstrates the importance of model physics for teleconnections to extreme precipitation.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  3. Horsing Around with Climate: Effect of Technology-Driven Landuse Change on Extreme Precipitation

    Science.gov (United States)

    Sines, T. R.; Arritt, R. W.

    2016-12-01

    The shift from work animals such as horses to mechanized labor and transport led to a decrease in acreage devoted to small grains (primarily oats) in the United States. Land formerly devoted to these crops was converted mostly to soybeans, which saw a forty-fold increase in planted acreage from 1940 to present. The same period saw an increase in extreme precipitation over the continental United States. We investigate possible connections between this agricultural landuse modification and precipitation changes in the central United States using the WRF-ARW model coupled with the Community Land Model. Crop acreages for maize, soybean, winter wheat, spring wheat, and other C3 and C4 crops were reconstructed for 1940-2010 using county-level data. This landuse was then used as surface input for two regional climate simulations, one using constant 1940s landuse and another using constant 2010 landuse. The landuse change was found to produce a shift in the precipitation intensity spectrum, with simulations using 2010 landuse having higher frequencies for heavier precipitation amounts and lower frequencies of light amounts compared to 1940s landuse. The break point for this shift corresponded to daily precipitation of about 24 mm. This indicates that agricultural landuse change has contributed to the observed trend in extreme precipitation, increasing the frequency of heavy daily rainfall.

  4. Continuous and discrete extreme climatic events affecting the dynamics of a high-arctic reindeer population.

    Science.gov (United States)

    Chan, Kung-Sik; Mysterud, Atle; Øritsland, Nils Are; Severinsen, Torbjørn; Stenseth, Nils Chr

    2005-10-01

    Climate at northern latitudes are currently changing both with regard to the mean and the temporal variability at any given site, increasing the frequency of extreme events such as cold and warm spells. Here we use a conceptually new modelling approach with two different dynamic terms of the climatic effects on a Svalbard reindeer population (the Brøggerhalvøya population) which underwent an extreme icing event ("locked pastures") with 80% reduction in population size during one winter (1993/94). One term captures the continuous and linear effect depending upon the Arctic Oscillation and another the discrete (rare) "event" process. The introduction of an "event" parameter describing the discrete extreme winter resulted in a more parsimonious model. Such an approach may be useful in strongly age-structured ungulate populations, with young and very old individuals being particularly prone to mortality factors during adverse conditions (resulting in a population structure that differs before and after extreme climatic events). A simulation study demonstrates that our approach is able to properly detect the ecological effects of such extreme climate events.

  5. Precipitation and temperatures extremes in East Africa in past and future climate

    OpenAIRE

    Kuya, Elinah Khasandi

    2016-01-01

    Climate change has increased extreme weather events over the planet. The most robust changes in East Africa (EA) are for daily temperature and precipitation, where high-impact extreme values have become more common. The overall magnitude, seasonal distribution of precipitation and its inter-annual variability have been altered. East Africa experiences some of the most severe convective storms in the world. They can come without warning and are becoming more frequent. These changes present sig...

  6. Climate change impact on groundwater levels: ensemble modelling of extreme values

    Directory of Open Access Journals (Sweden)

    J. Kidmose

    2012-06-01

    Full Text Available This paper presents a first attempt to estimate future groundwater levels by applying extreme value statistics on predictions from a hydrological model. Climate for the future period, 2081–2100, are represented by projections from nine combinations of three global climate models and six regional climate models, and downscaled with two different methods. An integrated surface water/groundwater model is forced with precipitation, temperature, and evapotranspiration from the 18 model – and downscaling combinations. Extreme value analyses are performed on the hydraulic head changes from a control period (1991–2010 to the future period for the 18 combinations. Hydraulic heads for return periods of 21, 50 and 100 yr (T21–100 are estimated. Three uncertainty sources are evaluated; climate models, downscaling and extreme value statistics. Of these sources, downscaling dominates for the higher return periods of 50 and 100 yr, whereas uncertainty from climate models and downscaling are similar for lower return periods. Uncertainty from the extreme value statistics only contribute up to around 10% of the uncertainty from the three sources.

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

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Steed, Chad A [ORNL; Evans, Katherine J [ORNL; Harney, John F [ORNL; Jewell, Brian C [ORNL; Shipman, Galen M [ORNL; Smith, Brian E [ORNL; Thornton, Peter E [ORNL; Williams, Dean N. [Lawrence Livermore National Laboratory (LLNL)

    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.

  9. Impacts of climate change on rainfall extremes and urban drainage systems: A review

    DEFF Research Database (Denmark)

    Arnbjerg-Nielsen, Karsten; Willems, P.; Olsson, J.

    2013-01-01

    A review is made of current methods for assessing future changes in urban rainfall extremes and their effects on urban drainage systems, due to anthropogenic-induced climate change. The review concludes that in spite of significant advances there are still many limitations in our understanding of...... drainage infrastructure considering climate change impacts and co-optimizing these with other objectives will become ever more important to keep our cities habitable into the future. © IWA Publishing 2013....

  10. Extreme Winter Cyclones in the North Atlantic in a Last Millennium Climate Simulation with CESM1.0.1

    Science.gov (United States)

    Blumer, Sandro R.; Raible, Christoph C.; Lehner, Flavio; Stocker, Thomas F.

    2016-04-01

    Extreme cyclones and their associated impacts are a major threat to mankind, as they often result in heavy precipitation events and severe winds. The last millennium is closest to the Anthropocene and has the best coverage of paleo-climatic information. Therefore, it can serve as a test bed for estimating natural forcing variations beyond the recent observational period and can deliver insight into the frequency and intensity of extreme events, including strong cyclones and their dependency on internal variability and external forcing. The aim of this study is to investigate how the frequency and intensity of extreme cyclones in the North Atlantic have changed in the last millennium, and investigate phases which deviate more than one standard deviation. In particular the changes during prolonged cold and warm periods and the 21st century are analysed to assess the external forcing imprint. We use a comprehensive fully-coupled transient climate simulation of the last millennium (AD 1000-2100) with a relatively high spatial (0.9x1.25 degrees) resolution. Cyclones are then detected and tracked in 12-hourly output using an algorithm that is based on the geopotential height field on 1000 hPa. In addition to the tracking, a Gaussian function is fitted to the depressions in the geopotential height field at every time step in order to have a geometric representation of the low pressure systems. Additionally, two intensity indices for extreme cyclones are defined: the 90 percentile of the mean gradient in geopotential and the 90 percentile of the precipitation within a radius of one standard deviation of the approximated Gaussian function around the cyclone. These criteria consider two aspects of cyclone's intensity: extremes in wind and precipitation. A 30-yr running window is applied to the entire simulation. Within each window the cyclone frequency and the indices for extreme wind and extreme precipitation cyclones are averaged. This analysis reveals decadal to

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

    Science.gov (United States)

    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. Climate indices over the last three decades in Tunisia using Weather Research and Forecasting Model:WRF

    Science.gov (United States)

    Deli, Meriem; Mkhinini, Nadia; Sadok Guellouz, Mohamed; Benjabrallah, Sadok

    2016-04-01

    Tunisia is a country situated in the south of the mediterannen basin. This region undergoes direct and indirect effects of climate change. Actually, we notice that summer temperatures have risen during the last decades. Nevertheless research on the tunisian climate are not well developed and are mainly based on observations; short and mid term forecast are not available for the tunisian case. In this context we have studied the climate properties of Tunisia over the last 30 years using Weather Research and Forecasting model WRF. Afterwards we compared our results to the observations that we have obteined on behalf of the National Institute of Meteorology. Results were then used to calculate different climate indices related to the air temperature such as extreme values during a specific period exceeding specific limits (Percentile), warm and cold spell duration and growing season length. We admit that we have created a reliable database for the Tunisian climate.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  15. Spatial and temporal variations of Norwegian geohazards in a changing climate, the GeoExtreme Project

    Directory of Open Access Journals (Sweden)

    C. Jaedicke

    2008-08-01

    Full Text Available Various types of slope processes, mainly landslides and avalanches (snow, rock, clay and debris pose together with floods the main geohazards in Norway. Landslides and avalanches have caused more than 2000 casualties and considerable damage to infrastructure over the last 150 years. The interdisciplinary research project "GeoExtreme" focuses on investigating the coupling between meteorological factors and landslides and avalanches, extrapolating this into the near future with a changing climate and estimating the socioeconomic implications. The main objective of the project is to predict future geohazard changes in a changing climate. A database consisting of more than 20 000 recorded historical events have been coupled with a meteorological database to assess the predictability of landslides and avalanches caused by meteorological conditions. Present day climate and near future climate scenarios are modelled with a global climate model on a stretched grid, focusing on extreme weather events in Norway. The effects of climate change on landslides and avalanche activity are studied in four selected areas covering the most important climatic regions in Norway. The statistical analysis of historical landslide and avalanche events versus weather observations shows strong regional differences in the country. Avalanches show the best correlation with weather events while landslides and rockfalls are less correlated. The new climate modelling approach applying spectral nudging to achieve a regional downscaling for Norway proves to reproduce extreme events of precipitation much better than conventional modelling approaches. Detailed studies of slope stabilities in one of the selected study area show a high sensitivity of slope stability in a changed precipitation regime. The value of elements at risk was estimated in one study area using a GIS based approach that includes an estimation of the values within given present state hazard zones. The ongoing

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

    Science.gov (United States)

    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

  17. Economic Growth in the Face of Weather and Climate Extremes: A Call for Better Data

    Science.gov (United States)

    Pendleton, Linwood; Karl, Thomas R.; Mills, Evan

    2013-06-01

    The U.S. economy has grown to be the world's largest, even in the face of the most varied and costly weather and climate extremes on the planet (see http://www.munichreamerica.com/webinars/2013_01_natcatreview/MunichRe_III_NatCat01032013.pdf). Nevertheless, these extremes continue to take a toll on the nation, diverting public and private funds while limiting economic growth and jobs and threatening the well-being of Americans. Extreme weather events affect every state and manifest differently by region (see Figure 1 in Supporting Information in the online version of this Forum and http://www.ncdc.noaa.gov/billions/summary-stats).

  18. Exploring the interannual variability of extreme wave climate in the Northeast Atlantic Ocean

    Science.gov (United States)

    Izaguirre, Cristina; Menéndez, Melisa; Camus, Paula; Méndez, Fernando J.; Mínguez, Roberto; Losada, Inigo J.

    2012-12-01

    The extreme wave climate is of paramount importance for: (i) off-shore and coastal engineering design, (ii) ship design and maritime transportation, or (iii) analysis of coastal processes. Identifying the synoptic patterns that produce extreme waves is necessary to understand the wave climate for a specific location. Thus, a characterization of these weather patterns may allow the study of the relationships between the magnitude and occurrence of extreme wave events and the climate system. The aim of this paper is to analyze the interannual variability of extreme wave heights. For this purpose, we present a methodological framework and its application to an area over the North East (NE) Atlantic Ocean. The climatology in the NE Atlantic is analyzed using the self-organizing maps (SOMs). The application of this clustering technique to monthly mean sea level pressure fields provides a continuum of synoptic categorizations compared with discrete realizations produced through most traditional methods. The extreme wave climate has been analyzed by means of monthly maxima of the significant wave height (SWH) in several locations over the NE Atlantic. A statistical approach based on a time-dependent generalized extreme value (GEV) distribution has been applied. The seasonal variation was characterized and, afterwards, the interannual variability was studied throughout regional pressure patterns. The anomalies of the 50-year return level estimates of SWH, due to interannual variability have been projected into the weather types of SOM. It provides a comprehensive visual representation, which relates the weather type with the positive or negative contribution to extreme waves over the selected locations.

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

    Science.gov (United States)

    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 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 relationship in the future climate. This implies negligible regional changes of relative humidity in the future despite the large warming and drying over the Mediterranean. This suggests that the Mediterranean Sea is the primary source of moisture which counteracts the drying and warming impacts on relative humidity in parts of the Mediterranean region.

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

    Science.gov (United States)

    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

  1. How extreme are extremes?

    Science.gov (United States)

    Cucchi, Marco; Petitta, Marcello; Calmanti, Sandro

    2016-04-01

    High temperatures have an impact on the energy balance of any living organism and on the operational capabilities of critical infrastructures. Heat-wave indicators have been mainly developed with the aim of capturing the potential impacts on specific sectors (agriculture, health, wildfires, transport, power generation and distribution). However, the ability to capture the occurrence of extreme temperature events is an essential property of a multi-hazard extreme climate indicator. Aim of this study is to develop a standardized heat-wave indicator, that can be combined with other indices in order to describe multiple hazards in a single indicator. The proposed approach can be used in order to have a quantified indicator of the strenght of a certain extreme. As a matter of fact, extremes are usually distributed in exponential or exponential-exponential functions and it is difficult to quickly asses how strong was an extreme events considering only its magnitude. The proposed approach simplify the quantitative and qualitative communication of extreme magnitude

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  9. Extreme summer heat in Phoenix, Arizona (USA under global climate change (2041-2070

    Directory of Open Access Journals (Sweden)

    Grossman-Clarke, Susanne

    2014-09-01

    Full Text Available Summer extreme heat events in the arid Phoenix, Arizona (USA metropolitan region for the period 2041-2070 are projected based on the ensemble of ten climate models from the North American Regional Climate Change Assessment Program for the SRES A2 greenhouse gas emissions scenario by the Intergovernmental Panel on Climate Change. Extreme heat events are identified by measures related to two thresholds of the maximum daily air temperature distribution for the historical reference period 1971-2000. Comparing this reference period to the model ensemble-mean, the frequency of extreme heat events is projected to increase by a factor of six to 1.9 events per summer and the average number of event days per year is projected to increase by a factor of 14. The inter-model range for the average number of EHE days per summer is larger for the projected climate, 10.6 to 42.2 days, than for simulations of the past climate simulations (1.5 to 2.4 days.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2011-12-01

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

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

    Science.gov (United States)

    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

  15. Mangrove expansion and contraction at a poleward range limit: Climate extremes and land-ocean temperature gradients

    Science.gov (United States)

    Osland, Michael J.; Day, Richard H.; Hall, Courtney T.; Brumfield, Marisa D; Dugas, Jason; Jones, William R.

    2017-01-01

    Within the context of climate change, there is a pressing need to better understand the ecological implications of changes in the frequency and intensity of climate extremes. Along subtropical coasts, less frequent and warmer freeze events are expected to permit freeze-sensitive mangrove forests to expand poleward and displace freeze-tolerant salt marshes. Here, our aim was to better understand the drivers of poleward mangrove migration by quantifying spatiotemporal patterns in mangrove range expansion and contraction across land-ocean temperature gradients. Our work was conducted in a freeze-sensitive mangrove-marsh transition zone that spans a land-ocean temperature gradient in one of the world's most wetland-rich regions (Mississippi River Deltaic Plain; Louisiana, USA). We used historical air temperature data (1893-2014), alternative future climate scenarios, and coastal wetland coverage data (1978-2011) to investigate spatiotemporal fluctuations and climate-wetland linkages. Our analyses indicate that changes in mangrove coverage have been controlled primarily by extreme freeze events (i.e., air temperatures below a threshold zone of -6.3 to -7.6 °C). We expect that in the past 121 years, mangrove range expansion and contraction has occurred across land-ocean temperature gradients. Mangrove resistance, resilience, and dominance were all highest in areas closer to the ocean where temperature extremes were buffered by large expanses of water and saturated soil. Under climate change, these areas will likely serve as local hotspots for mangrove dispersal, growth, range expansion, and displacement of salt marsh. Collectively, our results show that the frequency and intensity of freeze events across land-ocean temperature gradients greatly influences spatiotemporal patterns of range expansion and contraction of freeze-sensitive mangroves. We expect that, along subtropical coasts, similar processes govern the distribution and abundance of other freeze

  16. Possible Impact of climate change on future extreme precipitation of the Oldman, Bow and Red Deer River Basins of Alberta

    Science.gov (United States)

    Yew Gan, Thian; Gizaw, Mesgana

    2016-04-01

    The impact of climate change on extreme precipitation events in the Oldman (ORB), Bow, (BRB) and Red Deer (RRB) River Basins of southern Alberta, Canada, was assessed using six extreme climate indices for the rainy period of May-August (MJJA), and 9-km resolution Special Report on Emission Scenarios (SRES) A2 and A1B climate scenarios of four Coupled Model Intercomparison Project Phase 3 (CMIP3) Global Climate Models (GCMs) dynamically downscaled by a regional climate model, MM5. R95p of the three study sites showed an increase of 4% for the 2050s (2041-2070) and 10% for the 2080s (2071-2100) period, whereas R99p increased by 39% (2050s) and 42% (2080s) which suggest a projected increase in the volume of precipitation expected in future very wet and particularly extremely wet days. Similarly, R20mm, P30yr, RX1day and RX5day are also projected to increase by about 15% by the mid- and late 21st century in the three study sites. However, compared to BRB and RRB, ORB located in the southernmost part of the study site is projected to undergo a relatively higher increase in both temperature and precipitation intensity, which is assessed in terms of indices such as P30yr, RX1day and RX5day. On the other hand, RRB and BRB are projected to experience higher increase in R20mm, which suggest a relatively higher increase in the number of very heavy precipitation days projected for these two basins. Overall, these results suggest that in the 2050s and 2080s, southern Alberta will be expected to experience more frequent and severe intensive storm events in the MJJA season that could potentially increase the risk of future flooding in this region. Ref: Gizaw, M., and Gan, T. Y., 2015, Possible Impact of climate change on future extreme precipitation of the Oldman, Bow and Red Deer River Basins of Alberta, Int. Journal Climatology, DOI:10.1002/joc.4338

  17. Lifecycle Assessments of Railway Bridge Transitions Exposed to Extreme Climate Events

    Directory of Open Access Journals (Sweden)

    Sadudee Setsobhonkul

    2017-06-01

    Full Text Available Railway track components located at bridge transition zones or approach areas suffer from impact load and vibrations caused by abrupt changes in track stiffness on the bridge and the subgrade. The numerous strategies that can be used to mitigate these abrupt track stiffness changes rely on one of two concepts. The first concept is that of providing a gradual stiffness change, and the second is that of equalizing the track stiffness. A number of such mitigation methods have been developed and implemented over recent decades. Construction activities associated with these methods require various materials, processes, and uses of time, costs, and carbon emissions. In this study, eight of the most common techniques for railway bridge transition mitigation, including under ballast mats (UBMs, soft baseplates, under sleeper pads (USPs, rail pads, embankment treatments, transition slabs, ballast bonding, and wide sleepers, are compared. This study benchmarks the costs and carbon emissions of these eight mitigation techniques over the 50-year lifespan of a railway system subject to identical probabilities of four environmental scenarios: a control case, extremely high temperatures, extremely low temperatures, and flash flooding. This unprecedented study systemically investigates the effectiveness of the mitigation methods while considering the effects of 30 and 100 m bridge span lengths. Our results indicate that railway engineers should adopt different mitigation methods for different scenarios. The soft baseplate is the most appropriate method for a short-span bridge in the control case and the case of flash flooding, while ballast bonding is better for long-span railway bridges. Embankment treatment is recommended for both high- and low-extreme temperatures. However, its applicability is limited when the differential track stiffness is extremely high. Hence, alternatives that are 5–25% more expensive are proposed in parallel. The alternative

  18. Geomorphic responses as indicators of paleoclimate and climatic change

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

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

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Petra M., E-mail: pkklein@ou.edu [School of Meteorology, University of Oklahoma, Norman, OK (United States); Coffman, Reid, E-mail: rcoffma4@kent.edu [College of Architecture and Environmental Design, Kent State University, Kent, OH (United States)

    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. Evaluating the influence of long term historical climate change on catchment hydrology – using drought and flood indices

    Directory of Open Access Journals (Sweden)

    J. C. Refsgaard

    2013-02-01

    Full Text Available This study uses a 133 yr data set from the 1055 km2 Skjern River catchment in a western Danish catchment to evaluate: long-term past climate changes in the area; the capability of a conceptual hydrological model NAM to simulate climate change impacts on river discharge; and the occurrences of droughts and floods in a changing climate. The degree of change in the climatic variables is examined using the non-parametric Mann-Kendall test. During the last 133 yr the area has experienced a significant change in precipitation of 46% and a temperature change of 1.3 °C leading to (simulated increases in discharge of 103% and groundwater recharge of 172%. Only a small part of the past climatic changes was found to be correlated to the climatic drivers: NAO, SCA and AMO. The NAM model was calibrated on the period 1961–1970 and showed generally an excellent match between simulated and observed discharge. The capability of the hydrological model to predict climate change impact was investigated by looking at performances outside the calibration period. The results showed a reduced model fit, especially for the modern time periods (after the 1970s, and not all hydrological changes could be explained. This might indicate that hydrological models cannot be expected to predict climate change impacts on discharge as accurately in the future, as they perform under present conditions, where they can be calibrated. The (simulated stream discharge was subsequently analyzed using flood and drought indices based on the threshold method. The extreme signal was found to depend highly on the period chosen as reference to normal. The analysis, however, indicated enhanced amplitude of the hydrograph towards the drier extremes superimposed on the overall discharge increase leading to more relative drought periods.

  2. Quantifying population exposure to airborne particulate matter during extreme events in California due to climate change

    Directory of Open Access Journals (Sweden)

    A. Mahmud

    2012-02-01

    Full Text Available The effect of climate change on population-weighted concentrations of particulate matter (PM during extreme events was studied using the Parallel Climate Model (PCM, the Weather Research and Forecasting (WRF model and the UCD/CIT 3-D photochemical air quality model. A "business as usual" (B06.44 global emissions scenario was dynamically downscaled for the entire state of California between the years 2000–2006 and 2047–2053. Air quality simulations were carried out for 1008 days in each of the present-day and future climate conditions using year-2000 emissions. Population-weighted concentrations of PM0.1, PM2.5, and PM10 total mass, components species, and primary source contributions were calculated for California and three air basins: the Sacramento Valley air basin (SV, the San Joaquin Valley air basin (SJV and the South Coast Air Basin (SoCAB. Results over annual-average periods were contrasted with extreme events.

    Climate change between 2000 vs. 2050 did not cause a statistically significant change in annual-average population-weighted PM2.5 mass concentrations within any major sub-region of California in the current study. Climate change did alter the annual-average composition of the airborne particles in the SoCAB, with notable reductions of elemental carbon (EC; −3% and organic carbon (OC; −3% due to increased annual-average wind speeds that diluted primary concentrations from gasoline combustion (−3% and food cooking (−4%. In contrast, climate change caused significant increases in population-weighted PM2.5 mass concentrations in central California during extreme events. The maximum 24-h average PM2.5 concentration experienced by an average person during a ten-year period in the SJV increased by 21% due to enhanced production of secondary particulate matter (manifested as NH4NO3. In general, climate change caused increased

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    Detailed understanding of a possible decoupling between climatic drivers of plant productivity and the response of ecosystems vegetation is required. We compared trends in six NDVI metrics (1982-2010) derived from the GIMMS3g dataset with modelled biomass productivity and assessed uncertainty...... in trend estimates. Annual total biomass weight (TBW) was calculated with the LINPAC model. Trends were determined using a simple linear regression, a Thiel-Sen medium slope and a piecewise regression (PWR) with two segments. Values of NDVI metrics were related to Net Primary Production (MODIS......-NPP) and TBWper biome and land-use type. The simple linear and Thiel-Sen trends did not differ much whereas PWR increased the fraction of explained variation, depending on the NDVI metric considered. A positive trend in TBW indicating more favorable climatic conditions was found for 24% of pixels on land...

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

    Science.gov (United States)

    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.

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

    Indian Academy of Sciences (India)

    P Guhathakurta; O P Sreejith; P A Menon

    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.

  6. Climatic and biotic extreme events moderate long-term responses of above- and belowground sub-Arctic heathland communities to climate change

    NARCIS (Netherlands)

    Bokhorst, Stef; Phoenix, Gareth K.; Berg, Matty P.; Callaghan, Terry V.; Kirby-Lambert, Christopher; Bjerke, Jarle W.

    2015-01-01

    Climate change impacts are not uniform across the Arctic region because interacting factors causes large variations in local ecosystem change. Extreme climatic events and population cycles of herbivores occur simultaneously against a background of gradual climate warming trends and can redirect ecos

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    Amélie Lescroël

    Full Text Available 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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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).

  12. Climate change impact assessment on urban rainfall extremes and urban drainage: Methods and shortcomings

    DEFF Research Database (Denmark)

    Willems, P.; Arnbjerg-Nielsen, Karsten; Olsson, J.;

    2012-01-01

    for assessing the impacts of climate change on precipitation at the urban catchment scale. Downscaling of results from global circulation models or regional climate models to urban catchment scales are needed because these models are not able to describe accurately the rainfall process at suitable high temporal......Cities are becoming increasingly vulnerable to flooding because of rapid urbanization, installation of complex infrastructure, and changes in the precipitation patterns caused by anthropogenic climate change. The present paper provides a critical review of the current state-of-the-art methods...... of average precipitation.In this paper, following an overview of some recent advances in the development of innovative methods for assessing the impacts of climate change on urban rainfall extremes as well as on urban hydrology and hydraulics, several existing difficulties and remaining challenges in dealing...

  13. Limitations and pitfalls of climate change impact analysis on urban rainfall extremes

    DEFF Research Database (Denmark)

    Willems, P.; Olsson, J.; Arnbjerg-Nielsen, Karsten

    to anthropogenic climate change. Current practices have several limitations and pitfalls, which are important to be considered by trend or climate change impact modellers and users of trend/impact results. Climate change may well be the driver that ensures that changes in urban drainage paradigms are identified...... and suitable solutions implemented. Design and optimization of urban drainage infrastructure considering climate change impacts and co-optimizing with other objectives will become ever more important to keep our cities liveable into the future.......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...

  14. Climate Change Impacts on Rainfall Extremes and Urban Drainage: a State-of-the-Art Review

    DEFF Research Database (Denmark)

    Willems, Patrick; Olsson, Jonas; Arnbjerg-Nielsen, Karsten

    2013-01-01

    to anthropogenic climate change. Current practices have several limitations and pitfalls, which are important to be considered by trend or climate change impact modellers and users of trend or impact results. The review (Willems et al., 2012) considers the following aspects: analysis of long-term historical trends...... due to anthropogenic climate change, analysis of long-term future trends due to anthropogenic climate change, and implications for urban drainage infrastructure design and management. A summary is provided in this paper.......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...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  17. Variability of space climate and its extremes with successive solar cycles

    Science.gov (United States)

    Chapman, Sandra; Hush, Phillip; Tindale, Elisabeth; Dunlop, Malcolm; Watkins, Nicholas

    2016-04-01

    Auroral geomagnetic indices coupled with in situ solar wind monitors provide a comprehensive data set, spanning several solar cycles. Space climate can be considered as the distribution of space weather. We can then characterize these observations in terms of changing space climate by quantifying how the statistical properties of ensembles of these observed variables vary between different phases of the solar cycle. We first consider the AE index burst distribution. Bursts are constructed by thresholding the AE time series; the size of a burst is the sum of the excess in the time series for each time interval over which the threshold is exceeded. The distribution of burst sizes is two component with a crossover in behaviour at thresholds ≈ 1000 nT. Above this threshold, we find[1] a range over which the mean burst size is almost constant with threshold for both solar maxima and minima. The burst size distribution of the largest events has a functional form which is exponential. The relative likelihood of these large events varies from one solar maximum and minimum to the next. If the relative overall activity of a solar maximum/minimum can be estimated, these results then constrain the likelihood of extreme events of a given size for that solar maximum/minimum. We next develop and apply a methodology to quantify how the full distribution of geomagnetic indices and upstream solar wind observables are changing between and across different solar cycles. This methodology[2] estimates how different quantiles of the distribution, or equivalently, how the return times of events of a given size, are changing. [1] Hush, P., S. C. Chapman, M. W. Dunlop, and N. W. Watkins (2015), Robust statistical properties of the size of large burst events in AE, Geophys. Res. Lett.,42 doi:10.1002/2015GL066277 [2] Chapman, S. C., D. A. Stainforth, N. W. Watkins, (2013) On estimating long term local climate trends , Phil. Trans. Royal Soc., A,371 20120287 DOI:10.1098/rsta.2012.0287

  18. Extreme climatic events constrain space use and survival of a ground-nesting bird.

    Science.gov (United States)

    Tanner, Evan P; Elmore, R Dwayne; Fuhlendorf, Samuel D; Davis, Craig A; Dahlgren, David K; Orange, Jeremy P

    2017-05-01

    Two fundamental issues in ecology are understanding what influences the distribution and abundance of organisms through space and time. While it is well established that broad-scale patterns of abiotic and biotic conditions affect organisms' distributions and population fluctuations, discrete events may be important drivers of space use, survival, and persistence. These discrete extreme climatic events can constrain populations and space use at fine scales beyond that which is typically measured in ecological studies. Recently, a growing body of literature has identified thermal stress as a potential mechanism in determining space use and survival. We sought to determine how ambient temperature at fine temporal scales affected survival and space use for a ground-nesting quail species (Colinus virginianus; northern bobwhite). We modeled space use across an ambient temperature gradient (ranging from -20 to 38 °C) through a maxent algorithm. We also used Andersen-Gill proportional hazard models to assess the influence of ambient temperature-related variables on survival through time. Estimated available useable space ranged from 18.6% to 57.1% of the landscape depending on ambient temperature. The lowest and highest ambient temperature categories (35 °C, respectively) were associated with the least amount of estimated useable space (18.6% and 24.6%, respectively). Range overlap analysis indicated dissimilarity in areas where Colinus virginianus were restricted during times of thermal extremes (range overlap = 0.38). This suggests that habitat under a given condition is not necessarily a habitat under alternative conditions. Further, we found survival was most influenced by weekly minimum ambient temperatures. Our results demonstrate that ecological constraints can occur along a thermal gradient and that understanding the effects of these discrete events and how they change over time may be more important to conservation of organisms than are average and broad

  19. The Effects of Model Resolution on the Simulation of Regional Climate Extreme Events

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The fifth-generation Pennsylvania State University/NCAR Mesoscale Model Version 3 (MM5V3) was used to simulate extreme heavy rainfall events over the Yangtze River Basin in June 1999. The effects of model's horizontal and vertical resolution on the extreme climate events were investigated in detail. In principle, the model was able to characterize the spatial distribution of monthly heavy precipitation. The results indicated that the increase in horizontal resolution could reduce the bias of the modeled heavy rain and reasonably simulate the change of daily precipitation during the study period. A finer vertical resolution led to obviously improve rainfall simulations with smaller biases, and hence, better resolve heavy rainfall events. The increase in both horizontal and vertical resolution could produce better predictions of heavy rainfall events. Not only the rainfall simulation altered in the cases of different horizontal and vertical grid spacing, but also other meteorological fields demonstrated diverse variations in terms of resolution change in the model. An evident improvement in the simulated sea level pressure resulted from the increase of horizontal resolution, but the simulation was insensitive to vertical grid spacing. The increase in vertical resolution could enhance the simulation of surface temperature as well as atmospheric circulation at low levels, while the simulation of circulation at middle and upper levels were found to be much less dependent on changing resolution. In addition, cumulus parameterization schemes showed high sensitivity to horizontal resolution. Different convective schemes exhibited large discrepancies in rainfall simulations with regards to changing resolution. The percentage of convective precipitation in the Grell scheme increased with increasing horizontal resolution. In contrast, the Kain-Fritsch scheme caused a reduced ratio of convective precipitation to total rainfall accumulations corresponding to increasing

  20. Climatic aspects of the variability of extreme storm occurrence and intensity in the western Black Sea

    Science.gov (United States)

    Valchev, Nikolay; Trifonova, Ekaterina; Andreeva, Nataliya; Eftimova, Petya

    2010-05-01

    The study considers potential changes in the storm occurrence and intensity over the western Black Sea through analysis of long term series of wind and wave conditions simulated with relatively high resolution. It is a result of coupling of atmospheric and wave models and spans period of more than 62 years (1948-2009). The wave hincast is driven with the global reanalysis data produced by ECMWF and NCEP/NCAR. The continuous dataset is reduced to a series of storms of considerable intensity and/or destructive potential through application of thresholds for filtration of weak seas. They are primarily based on storm impact on the coastal environment and principles for statistical representativeness. The climatic variability of occurrence and intensity of the selected extreme events is analyzed using different criteria such as number of stormy days, wind speed and wave height extremes. Particular consideration is paid to the mean wave energy per storm season and specific storm energy that are found to be more indicative for understanding of the storm pattern variability. Despite of the overall tendency for storminess decrease, there are no incontestable evidences corroborating a marked reduction of the storm intensity. While the total number of stormy hours diminishes, an increase of the mean wave energy is discernible. This is found to be caused by a change of the storm pattern: storms with short growth stage, energetic stage of full development and fast decay are more frequently observed. This storm type still provides significant energy input in the coastal zone and is able of producing considerable morphological impact, including damages. Such storms develop abruptly, therefore, timely prediction and mitigation of hazard effects become more complex to tackle with. Hence, little potential seems to exist for reducing the vulnerability to storms in the western Black Sea. That means the societies must begin to take such far-reaching implications into serious

  1. Seasonal precipitation extreme indices in mainland Portugal: trends and variability in the period 1941-2007

    Science.gov (United States)

    Santo, Fátima E.; Ramos, Alexandre M.; de Lima, M. Isabel P.; Trigo, Ricardo M.

    2013-04-01

    Changes in the precipitation regimes are expected to be accompanied by variations in the occurrence of extreme events, which in turn could be related to low frequency variability. The impact on the society and environment requires that the regional specificities are understood. For mainland Portugal, this work reports the results of the analysis of trends in selected precipitation indices calculated from daily precipitation data from 57 meteorological stations, recorded in the period 1941-2007; additionally we have also investigated the correlations between these indices and several modes of low frequency variability over the area. We focus on exploring regional differences and seasonal variations in the intensity, frequency and duration of extreme precipitation events. The precipitation indices were assessed at the seasonal scale and calculated at both the station and regional scales. Results sometimes highlight marked changes in seasonal precipitation and show that: i) trends in spring and autumn have opposite signals: statistically significant drying trends in the spring are accompanied by a reduction in precipitation extremes; in autumn, wetting trends are detected for all precipitation indices, although overall they are not significant at the 5% level; ii) there seems to be a tendency for a reduction in the duration of the rainy season; iii) the North Atlantic Oscillation (NAO) is the mode of variability that has the highest influence on precipitation extremes over mainland Portugal, particularly in the winter and autumn, and is one of the most important teleconnection patterns in all seasons. This work was partially supported by FEDER (Fundo Europeu de Desenvolvimento Regional) funds through the COMPETE (Programa Operacional Factores de Competitividade) and by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) through project STORMEx FCOMP-01-0124-FEDER-019524 (PTDC/AAC-CLI/121339/2010).

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

    Science.gov (United States)

    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

  3. Changes in Climate Extremes and Catastrophic Events in the Mongolian Plateau from 1951 to 2012

    DEFF Research Database (Denmark)

    Wang, Lei; Yao, Zhi-Jun; Jiang, Liguang;

    2016-01-01

    The spatiotemporal changes in 21 indices of extreme temperature and precipitation for the Mongolian Plateau from 1951 to 2012 were investigated on the basis of daily temperature and precipitation data from 70 meteorological stations. Changes in catastrophic events, such as droughts, floods...... in the daytime. The spatial changes in significant trends showed a good homogeneity and consistency in Inner Mongolia. Changes in the precipitation extremes were not as obvious as those in the temperature extremes. The spatial distributions in changes of precipitation extremes were complex. Adecreasing trend...

  4. Integration of climatic indices in an objective probabilistic model for establishing and mapping viticultural climatic zones in a region

    Science.gov (United States)

    Moral, Francisco J.; Rebollo, Francisco J.; Paniagua, Luis L.; García, Abelardo; Honorio, Fulgencio

    2016-05-01

    Different climatic indices have been proposed to determine the wine suitability in a region. Some of them are related to the air temperature, but the hydric component of climate should also be considered which, in turn, is influenced by the precipitation during the different stages of the grapevine growing and ripening periods. In this study, we propose using the information obtained from ten climatic indices [heliothermal index (HI), cool night index (CI), dryness index (DI), growing season temperature (GST), the Winkler index (WI), September mean thermal amplitude (MTA), annual precipitation (AP), precipitation during flowering (PDF), precipitation before flowering (PBF), and summer precipitation (SP)] as inputs in an objective and probabilistic model, the Rasch model, with the aim of integrating the individual effects of them, obtaining the climate data that summarize all main climatic indices, which could influence on wine suitability from a climate viewpoint, and utilizing the Rasch measures to generate homogeneous climatic zones. The use of the Rasch model to estimate viticultural climatic suitability constitutes a new application of great practical importance, enabling to rationally determine locations in a region where high viticultural potential exists and establishing a ranking of the climatic indices which exerts an important influence on wine suitability in a region. Furthermore, from the measures of viticultural climatic suitability at some locations, estimates can be computed using a geostatistical algorithm, and these estimates can be utilized to map viticultural climatic zones in a region. To illustrate the process, an application to Extremadura, southwestern Spain, is shown.

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

    Science.gov (United States)

    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.

  6. Effects of decreasing acid deposition and climate change on acid extremes in an upland stream

    Directory of Open Access Journals (Sweden)

    C. D. Evans

    2008-03-01

    Full Text Available This study assesses the major chemical processes leading to acid extremes in a small, moorland stream in mid-Wales, UK, which has been monitored since 1979. Results suggest that base cation (mainly calcium dilution, the "sea-salt effect", and elevated nitrate pulses, are the major causes of seasonal/episodic minima in acid neutralising capacity (ANC, and that the relative importance of these drivers has remained approximately constant during 25 years of decreasing acid deposition and associated long-term chemical recovery. Many of the chemical variations causing short-term reductions in stream acidity, particularly base cation dilution and organic acid increases, are closely related to changes in water-flowpath and therefore to stream discharge. Changes in the observed pH-discharge relationship over time indicate that high-flow pH has increased more rapidly than mean-flow pH, and therefore that episodes have decreased in magnitude since 1980. However a two-box application of the dynamic model MAGIC, whilst reproducing this trend, suggests that it will not persist in the long term, with mean ANC continuing to increase until 2100, but the ANC of the upper soil (the source of relatively acid water during high-flow episodes stabilising close to zero beyond 2030. With climate change predicted to lead to an increase in maximum flows in the latter half of the century, high-flow related acid episodes may actually become more rather than less severe in the long term, although the model suggests that this effect may be small. Two other predicted climatic changes could also detrimentally impact on acid episodes: increased severity of winter "sea-salt" episodes due to higher wind speeds during winter storms; and larger sulphate pulses due to oxidation of reduced sulphur held in organic soils, during more extreme summer droughts. At the Gwy, the near-coastal location and relatively small extent of peat soils suggest that sea-salt episodes may have the

  7. Relationship between climate extremes in Romania and their connection to large-scale air circulation

    Science.gov (United States)

    Barbu, Nicu; Ştefan, Sabina

    2015-04-01

    The aim of this paper is to investigate the connection between climate extremes (temperature and precipitation) in Romania and large-scale air circulation. Daily observational data of maximum air temperature and amount of precipitation for the period 1961-2010 were used to compute two seasonal indices associated with temperature and precipitation, quantifying their frequency, as follows: frequency of very warm days (FTmax90 ≥ 90th percentile), frequency of very wet days (FPp90; daily precipitation amount ≥ 90th percentile). Seasonally frequency of circulation types were calculated from daily circulation types determined by using two objective catalogues (GWT - GrossWetter-Typen and WLK - WetterLargenKlassifikation) from the COST733Action. Daily reanalysis data sets (sea level pressure, geopotential height at 925 and 500 hPa, u and v components of wind vector at 700 hPa and precipitable water content for the entire atmospheric column) build up by NCEP/NCAR, with 2.5°/2.5° lat/lon spatial resolution, were used to determine the circulation types. In order to select the optimal domain size related to the FTmax90 and the FPp90, the explained variance (EV) has been used. The EV determines the relation between the variance among circulation types and the total variance of the variable under consideration. This method quantifies the discriminatory power of a classification. The relationships between climate extremes in Romania and large-scale air circulation were investigated by using multiple linear regression model (MLRM), the predictands are FTmax90 and FPp90 and the circulation types were used as predictors. In order to select the independent predictors to build the MLRM the collinearity and multicollinearity analysis were performed. The study period is dividend in two periods: the period 1961-2000 is used to train the MLRM and the period 2001-2010 is used to validate the MLRM. The analytical relationship obtained by using MLRM can be used for future projection

  8. Long-term ERP time series as indicators for global climate variability and climate change

    Science.gov (United States)

    Lehmann, E.; Grötzsch, A.; Ulbrich, U.; Leckebusch, G. C.; Nevir, P.; Thomas, M.

    2009-04-01

    This study assesses whether variations in observed Earth orientation parameters (EOPs, IERS) such as length-of day (LOD EOP C04) and polar motion (PM EOP C04) can be applied as climate indicators. Data analyses suggest that observed EOPs are differently affected by parameters associated with the atmosphere and ocean. On interannual time scales the varying ocean-atmosphere effects on EOPs are in particular pronounced during episodes of the coupled ocean-atmosphere phenomenon El Niño-Southern Oscillation (ENSO). Observed ENSO anomalies of spatial patterns of parameters affected by atmosphere and ocean (climate indices and sea surface temperatures) are related to LOD and PM variability and associated with possible physical background processes. Present time analyses (1962 - 2000) indicate that the main source of the varying ENSO signal on observed LOD can be associated with anomalies of the relative angular momentum (AAM) related to variations in location and strength of jet streams of the upper troposphere. While on interannual time scales observed LOD and AAM are highly correlated (r=0.75), results suggest that strong El Niño events affect the observed LOD - AAM relation differently strong (explained variance 71%- 98%). Accordingly, the relation between AAM and ocean sea surface temperatures (SST) in the NIÑO 3.4 region differs (explained variances 15%-73%). Corresponding analysis is conducted on modelled EOPs (ERA40 reanalysis, ECHAM5-OM1) to obtain Earth rotation parameters undisturbed by core-mantle activities, and to study rotational variations under climate variability and change. A total of 91 strong El Niño events are analysed in coupled ocean-atmosphere ECHAM5-OM1 scenarios concerning the 20th century (20C), climate warming (A1B) and pre-industrial climate variability. Analyses on a total of 61 strong El Niño events covering a time period of 505 simulation years under pre-industrial climate conditions indicate a range of El Niño events with a strong or

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

    Directory of Open Access Journals (Sweden)

    Marcelo Zeri

    Full Text Available 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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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

  14. estimation of climatic parameters from solar indices using ground ...

    African Journals Online (AJOL)

    User

    show the effect of solar forcing on the climatic parameters at different locations in Kenya. Solar ... the various layers of the Earth's atmosphere. .... near Kericho town, in the western high lands of ... Ocean environment that covers the whole of the.

  15. Chromium Isotopes in Marine Carbonates - an Indicator for Climatic Change?

    Science.gov (United States)

    Frei, R.; Gaucher, C.

    2010-12-01

    Chromium (Cr) stable isotopes experience an increased interest as a tracer of Cr (VI) reduction in groundwater and thus showed their potential as a monitor of remediation of anthropogenic and natural contamination in water (Berna et al., 2009; Izbicki et al., 2008). Chromium stable isotopes in Fe-rich chemical sediments (BIFs and Fe-cherts) have recently also been used as a tracer for Earth's atmospheric oxygenation through time (Frei et al., 2009). We have applied the Cr isotope system to organic-rich carbonates from a late Ediacaran succession in Uruguay (Polanco Formation), from which we have previously analyzed BIFs with extremely fractionated (δ53Cr up to 5.0 ‰) Cr isotope signatures that are part of an underlying deep water clastic sediment (shale-dominated) sequence (Yerbal Formation) deposited in a glacio-marine environment (Gaucher et al.,2004). δ53Cr values of organic rich carbonates correlate with positive and negative carbon isotope excursions (δ13C PDB between -3 and +3 ‰) and with systematic changes in strontium isotope compositions, commonly interpreted as to reflect fluctuations in organic (photosynthetic algae) production related to fluctuations in atmospheric oxygen and weathering intensities, respectively. Slightly positively fractioned δ53Cr values (up to +0.25‰), paralleling positive (δ13C PDB and 87Sr/86Sr ratio excursions would thereby trace elevated atmospheric oxygen levels/pulses possibly related to glacier retreat/melting stages that caused bioproductivity to increase. While the causal link between these multiple isotopic tracers and the mechanisms of Cr stripping into carbonates has to be further investigated in detail, the first indications from this study point to a potentially promising use of stable Cr isotopes in organic-rich carbonates to monitor fluctuations of atmospheric oxygen, particularly over the Neoproterozoic and Phanerozoic ice age periods. E.C. Berna et al. (2010) Cr stable isotopes as indicators of Cr

  16. Changes in Climate Extremes and Catastrophic Events in the Mongolian Plateau from 1951 to 2012

    DEFF Research Database (Denmark)

    Wang, Lei; Yao, Zhi-Jun; Jiang, Liguang;

    2016-01-01

    The spatiotemporal changes in 21 indices of extreme temperature and precipitation for the Mongolian Plateau from 1951 to 2012 were investigated on the basis of daily temperature and precipitation data from 70 meteorological stations. Changes in catastrophic events, such as droughts, floods...... was shown for total precipitation from west to east as based on the spatial distribution of decadal trends. Drought was the most serious extreme disaster, and prolonged drought for longer than 3 yr occurred about every 7-11 yr. An increasing trend in the disaster area was apparent for flood events from 1951......, and snowstorms, were also investigated for the same period. The correlations between catastrophic events and the extreme indices were examined. The results show that the Mongolian Plateau experienced an asymmetric warming trend. Both the cold extremes and warm extremes showed greater warming at night than...

  17. Missing rings in Pinus halepensis – the missing link to relate the tree-ring record to extreme climatic events

    Directory of Open Access Journals (Sweden)

    Klemen eNovak

    2016-05-01

    Full Text Available Climate predictions for the Mediterranean Basin include increased temperatures, decreased precipitation, and increased frequency of extreme climatic events (ECE. These conditions are associated with decreased growth of trees and their increased vulnerability to pests and diseases. The anatomy of tree rings is responsive to these environmental conditions. Quantitatively, the width of a tree ring is largely determined by the rate and duration of cell division by the vascular cambium. In the Mediterranean climate, cambial cell division may occur throughout almost the entire year. Alternatively, cell division may stop during relatively cool and dry winters, only to resume in the same year with milder temperatures and increased availability of water. Under particularly adverse conditions, no xylem may be produced in parts of the stem, resulting in a missing ring (MR, which can link tree-ring anatomy to the occurrence of extreme events. A dendrochronological network of Pinus halepensis, a widespread tree species in the Mediterranean basin, was used to determine the relationship of MR to ECE. The network consisted of 113 sites throughout its distribution range. Binomial logistic regression analysis of 2595 MR series determined that MR increased in frequency with increased cambial age. Spatial analysis indicated that the geographic areas of southeastern Spain and northern Algeria contained the greatest frequency of MR. Further regression analysis indicated that the relationship of MR to total monthly precipitation and mean temperature was non-linear. In this first determination of climatic influences on MR, the formation of MR was most strongly associated with the combination of monthly mean temperature above 10°C from previous October till current February and total precipitation below 50 mm from previous September till current May. This conclusion is global and can be applied to every site across the distribution area. Rather than simply being a

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

    Science.gov (United States)

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

    Science.gov (United States)

    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

  20. The effects of climatic fluctuations and extreme events on running water ecosystems

    OpenAIRE

    Woodward, Guy; Bonada, Nuria; Brown, Lee E; Death, Russell G.; Durance, Isabelle; Gray, Clare; Hladyz, Sally; Mark E. Ledger; Milner, Alexander; Ormerod, Stephen; Thomson, Ross M.; Pawar, Samraat

    2016-01-01

    Most research on the effects of environmental change in freshwaters has focused on incremental changes in average conditions, rather than fluctuations or extreme events such as heatwaves, cold snaps, droughts, floods, or wildfires, which may have even more profound consequences. Such events are commonly predicted to increase in frequency, intensity, and duration with global climate change, with many systems being exposed to conditions with no recent historical precedent. We propose a mechanis...

  1. Ensuring Resilience of Natural Resources under Exposure to Extreme Climate Events

    OpenAIRE

    Brent Jacobs; Louise Boronyak-Vasco; Kristy Moyle; Peat Leith

    2016-01-01

    Natural resources directly support rural livelihoods and underpin much of the wealth of rural and regional Australia. Climate change manifesting as increasing frequency and or severity of extreme weather events poses a threat to sustainable management of natural resources because the recurrence of events may exceed the resilience of natural systems or the coping capacity of social systems. We report the findings of a series of participatory workshops with communities in eight discrete landsca...

  2. Extreme weather events and related disasters in the Philippines, 2004-08: a sign of what climate change will mean?

    Science.gov (United States)

    Yumul, Graciano P; Cruz, Nathaniel A; Servando, Nathaniel T; Dimalanta, Carla B

    2011-04-01

    Being an archipelagic nation, the Philippines is susceptible and vulnerable to the ill-effects of weather-related hazards. Extreme weather events, which include tropical cyclones, monsoon rains and dry spells, have triggered hazards (such as floods and landslides) that have turned into disasters. Financial resources that were meant for development and social services have had to be diverted in response, addressing the destruction caused by calamities that beset different regions of the country. Changing climatic patterns and weather-related occurrences over the past five years (2004-08) may serve as an indicator of what climate change will mean for the country. Early recognition of this possibility and the implementation of appropriate action and measures, through disaster risk management, are important if loss of life and property is to be minimised, if not totally eradicated. This is a matter of urgent concern given the geographical location and geological characteristics of the Philippines.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    2013-12-01

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

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

    Science.gov (United States)

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

    2016-09-01

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

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

    OpenAIRE

    June J.Cheng; Berry, Peter

    2013-01-01

    Objectives This study aimed at developing a list of key human health indicators for quantifying the health impacts of climate change in Canada. Methods A literature review was conducted in OVID Medline to identify health morbidity and mortality indicators currently used to quantify climate change impacts. Public health frameworks and other studies of climate change indicators were reviewed to identify criteria with which to evaluate the list of proposed key indicators and a rating scale was d...

  7. Extreme climatic events: reducing ecological and social systems vulnerabilities; Evenements climatiques extremes: reduire les vulnerabilites des systemes ecologiques et sociaux

    Energy Technology Data Exchange (ETDEWEB)

    Decamps, H.; Amatore, C.; Bach, J.F.; Baccelli, F.; Balian, R.; Carpentier, A.; Charnay, P.; Cuzin, F.; Davier, M.; Dercourt, J.; Dumas, C.; Encrenaz, P.; Jeannerod, M.; Kahane, J.P.; Meunier, B.; Rebut, P.H.; Salencon, J.; Spitz, E.; Suquet, P.; Taquet, P.; Valleron, A.J.; Yoccoz, J.C.; Chapron, J.Y.; Fanon, J.; Andre, J.C.; Auger, P.; Bourrelier, P.H.; Combes, C.; Derrida, B.; Laubier, L.; Laval, K.; Le Maho, Y.; Marsily, G. De; Petit, M.; Schmidt-Laine, C.; Birot, Y.; Peyron, J.L.; Seguin, B.; Barles, S.; Besancenot, J.P.; Michel-Kerjan, E.; Hallegatte, S.; Dumas, P.; Ancey, V.; Requier-Desjardins, M.; Ducharnes, A.; Ciais, P.; Peylin, P.; Kaniewski, D.; Van Campo, E.; Planton, S.; Manuguerra, J.C.; Le Bars, Y.; Lagadec, P.; Kessler, D.; Pontikis, C.; Nussbaum, R.

    2010-07-01

    The Earth has to face more and more devastating extreme events. Between 1970 and 2009, at the worldwide scale, the 25 most costly catastrophes all took place after 1987, and for more than half of them after 2001. Among these 25 catastrophes, 23 were linked to climate conditions. France was not spared: the December 1999 storms led to 88 deaths, deprived 3.5 million households of electricity and costed more than 9 billion euros. The 2003 heat wave led to about 15000 supernumerary deaths between August 1 and August 20. The recent Xynthia storm, with its flood barrier ruptures, provoked 53 deaths in addition to many other tragedies that took place in areas liable to flooding. In the present day context of climate change, we know that we must be prepared to even more dangerous events, sometimes unexpected before. These events can have amplified effects because of the urban development, the overpopulation of coastal areas and the anthropization of natural environments. They represent real 'poverty traps' for the poorest countries of the Earth. The anticipation need is real but is our country ready to answer it? Does it have a sufficient contribution to international actions aiming at reducing risks? Is his scientific information suitable? France is not less vulnerable than other countries. It must reinforce its prevention, its response and resilience capacities in the framework of integrated policies of catastrophes risk management as well as in the framework of climate change adaptation plans. This reinforcement supposes the development of vigilance systems with a better risk coverage and benefiting by the advances gained in the meteorology and health domains. It supposes a town and country planning allowing to improve the viability of ecological and social systems - in particular by protecting their diversity. Finally, this reinforcement requires inciting financial coverage solutions for catastrophes prevention and for their management once they have taken

  8. Relative impact of climate indicators and aerosols on tropical cyclones

    Science.gov (United States)

    Chiacchio, Marc; Pausata, Francesco; Messori, Gabriele; Hannachi, Abdel; Chin, Mian; Ekman, Annica; Barrie, Leonard

    2015-04-01

    This study assesses the most important environmental variables modulating tropical cyclone (TC) frequency in six different oceanic basins such as the East Pacific, West Pacific, North Atlantic, North Indian Ocean, South Indian Ocean, and South Pacific. To determine their influence, we used multiple linear regression between TC frequency and variations in meteorological variables and circulation indices as well as aerosol optical depth (AOD) anomalies over the tropical cyclone development areas for the period 1980-2009 (where the AOD was separated into the compounds black and organic carbon, sulfate dust and sea salt). Overall the low-level relative humidity in the North Atlantic, stratospheric aerosol burden in the East Pacific, and the black carbon burden in the North Indian basin showed the greatest relation with TC activity and were all with statistically significant and explained variances of 28%. Amongst the circulation modes of variability, the Atlantic Multidecadal Oscillation (AMO) and the El Nino Southern Oscillation (ENSO) appeared to be most important to TC activity with significant variances of 29% in the South Indian Ocean and 25% in the East Pacific basins, respectively. We also examined the inter-basin relationship between the different environmental variables in one basin and the cyclone frequency in another basin. Overall the strongest connections were found between North Atlantic basin variables and North Indian TCs while the weakest links were found between West Pacific basin variables and South Pacific TCs. Lastly, because the strongest cooling of the lower stratospheric temperature was found over the North Atlantic since the last few decades and because the cooling could explain a variance of 15% of TC frequency in that same basin, we investigated five global climate models from the historical runs of the CMIP5 archive to determine whether they were able to capture this cooling in the lower stratosphere. Although the models were able to

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

    Science.gov (United States)

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

    2013-04-01

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

  10. Future extreme events in European climate: An exploration of regional climate model projections

    DEFF Research Database (Denmark)

    Beniston, M.; Stephenson, D.B.; Christensen, O.B.

    2007-01-01

    -90) and future (2071-2 100) climate on the basis of regional climate model simulations produced by the PRUDENCE project. A summary of the main results follows. Heat waves - Regional surface warming causes the frequency, intensity and duration of heat waves to increase over Europe. By the end of the twenty first......, and the detailed patterns of these changes are sensitive to the choice of the driving global model. In the case of precipitation, variation between models can exceed both internal variability and variability between different emissions scenarios....... regions of Holland, Germany and Denmark, in particular. These results are found to depend to different degrees on model formulation. While the responses of heat waves are robust to model formulation, the magnitudes of changes in precipitation and wind speed are sensitive to the choice of regional model...

  11. Quantifying the influence of global warming on unprecedented extreme climate events.

    Science.gov (United States)

    Diffenbaugh, Noah S; Singh, Deepti; Mankin, Justin S; Horton, Daniel E; Swain, Daniel L; Touma, Danielle; Charland, Allison; Liu, Yunjie; Haugen, Matz; Tsiang, Michael; Rajaratnam, Bala

    2017-05-09

    Efforts to understand the influence of historical global warming on individual extreme climate events have increased over the past decade. However, despite substantial progress, events that are unprecedented in the local observational record remain a persistent challenge. Leveraging observations and a large climate model ensemble, we quantify uncertainty in the influence of global warming on the severity and probability of the historically hottest month, hottest day, driest year, and wettest 5-d period for different areas of the globe. We find that historical warming has increased the severity and probability of the hottest month and hottest day of the year at >80% of the available observational area. Our framework also suggests that the historical climate forcing has increased the probability of the driest year and wettest 5-d period at 57% and 41% of the observed area, respectively, although we note important caveats. For the most protracted hot and dry events, the strongest and most widespread contributions of anthropogenic climate forcing occur in the tropics, including increases in probability of at least a factor of 4 for the hottest month and at least a factor of 2 for the driest year. We also demonstrate the ability of our framework to systematically evaluate the role of dynamic and thermodynamic factors such as atmospheric circulation patterns and atmospheric water vapor, and find extremely high statistical confidence that anthropogenic forcing increased the probability of record-low Arctic sea ice extent.

  12. Quantifying the influence of global warming on unprecedented extreme climate events

    Science.gov (United States)

    Diffenbaugh, Noah S.; Singh, Deepti; Mankin, Justin S.; Horton, Daniel E.; Swain, Daniel L.; Touma, Danielle; Charland, Allison; Liu, Yunjie; Haugen, Matz; Tsiang, Michael; Rajaratnam, Bala

    2017-05-01

    Efforts to understand the influence of historical global warming on individual extreme climate events have increased over the past decade. However, despite substantial progress, events that are unprecedented in the local observational record remain a persistent challenge. Leveraging observations and a large climate model ensemble, we quantify uncertainty in the influence of global warming on the severity and probability of the historically hottest month, hottest day, driest year, and wettest 5-d period for different areas of the globe. We find that historical warming has increased the severity and probability of the hottest month and hottest day of the year at >80% of the available observational area. Our framework also suggests that the historical climate forcing has increased the probability of the driest year and wettest 5-d period at 57% and 41% of the observed area, respectively, although we note important caveats. For the most protracted hot and dry events, the strongest and most widespread contributions of anthropogenic climate forcing occur in the tropics, including increases in probability of at least a factor of 4 for the hottest month and at least a factor of 2 for the driest year. We also demonstrate the ability of our framework to systematically evaluate the role of dynamic and thermodynamic factors such as atmospheric circulation patterns and atmospheric water vapor, and find extremely high statistical confidence that anthropogenic forcing increased the probability of record-low Arctic sea ice extent.

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

    Science.gov (United States)

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

    2016-10-01

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

  14. Diagnostic indicators for integrated assessment models of climate policy

    NARCIS (Netherlands)

    Kriegler, Elmar; Petermann, Nils; Krey, Volker; Schwanitz, Valeria Jana; Luderer, Gunnar; Ashina, Shuichi; Bosetti, Valentina; Eom, Jiyong; Kitous, Alban; Méjean, Aurélie; Paroussos, Leonidas; Sano, Fuminori; Turton, Hal; Wilson, Charlie; Van Vuuren, Detlef P.

    2015-01-01

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

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

    Science.gov (United States)

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

    2016-04-01

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

  16. Uncertainty and extreme events in future climate and hydrologic projections for the Pacific Northwest: providing a basis for vulnerability and core/corridor assessments

    Science.gov (United States)

    Littell, Jeremy S.; Mauger, Guillaume S.; Salathe, Eric P.; Hamlet, Alan F.; Lee, Se-Yeun; Stumbaugh, Matt R.; Elsner, Marketa; Norheim, Robert; Lutz, Eric R.; Mantua, Nathan J.

    2014-01-01

    The purpose of this project was to (1) provide an internally-consistent set of downscaled projections across the Western U.S., (2) include information about projection uncertainty, and (3) assess projected changes of hydrologic extremes. These objectives were designed to address decision support needs for climate adaptation and resource management actions. Specifically, understanding of uncertainty in climate projections – in particular for extreme events – is currently a key scientific and management barrier to adaptation planning and vulnerability assessment. The new dataset fills in the Northwest domain to cover a key gap in the previous dataset, adds additional projections (both from other global climate models and a comparison with dynamical downscaling) and includes an assessment of changes to flow and soil moisture extremes. This new information can be used to assess variations in impacts across the landscape, uncertainty in projections, and how these differ as a function of region, variable, and time period. In this project, existing University of Washington Climate Impacts Group (UW CIG) products were extended to develop a comprehensive data archive that accounts (in a reigorous and physically based way) for climate model uncertainty in future climate and hydrologic scenarios. These products can be used to determine likely impacts on vegetation and aquatic habitat in the Pacific Northwest (PNW) region, including WA, OR, ID, northwest MT to the continental divide, northern CA, NV, UT, and the Columbia Basin portion of western WY New data series and summaries produced for this project include: 1) extreme statistics for surface hydrology (e.g. frequency of soil moisture and summer water deficit) and streamflow (e.g. the 100-year flood, extreme 7-day low flows with a 10-year recurrence interval); 2) snowpack vulnerability as indicated by the ratio of April 1 snow water to cool-season precipitation; and, 3) uncertainty analyses for multiple climate

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    1999-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Susan C. Walls

    2013-03-01

    Full Text Available 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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  2. Climate change and the effects of temperature extremes on Australian flying-foxes.

    Science.gov (United States)

    Welbergen, Justin A; Klose, Stefan M; Markus, Nicola; Eby, Peggy

    2008-02-22

    Little is known about the effects of temperature extremes on natural systems. This is of increasing concern now that climate models predict dramatic increases in the intensity, duration and frequency of such extremes. Here we examine the effects of temperature extremes on behaviour and demography of vulnerable wild flying-foxes (Pteropus spp.). On 12 January 2002 in New South Wales, Australia, temperatures exceeding 42 degrees C killed over 3500 individuals in nine mixed-species colonies. In one colony, we recorded a predictable sequence of thermoregulatory behaviours (wing-fanning, shade-seeking, panting and saliva-spreading, respectively) and witnessed how 5-6% of bats died from hyperthermia. Mortality was greater among the tropical black flying-fox, Pteropus alecto (10-13%) than the temperate grey-headed flying-fox, Pteropus poliocephalus (less than 1%), and young and adult females were more affected than adult males (young, 23-49%; females, 10-15%; males, less than 3%). Since 1994, over 30000 flying-foxes (including at least 24500 P. poliocephalus) were killed during 19 similar events. Although P. alecto was relatively less affected, it is currently expanding its range into the more variable temperature envelope of P. poliocephalus, which increases the likelihood of die-offs occurring in this species. Temperature extremes are important additional threats to Australian flying-foxes and the ecosystem services they provide, and we recommend close monitoring of colonies where temperatures exceeding 42.0 degrees C are predicted. The effects of temperature extremes on flying-foxes highlight the complex implications of climate change for behaviour, demography and species survival.

  3. Estimating the Effect of Climate Change on Crop Yields and Farmland Values: The Importance of Extreme Temperatures

    Science.gov (United States)

    This is a presentation titled Estimating the Effect of Climate Change on Crop Yields and Farmland Values: The Importance of Extreme Temperatures that was given for the National Center for Environmental Economics

  4. Statistical Analysis of Wave Climate Data Using Mixed Distributions and Extreme Wave Prediction

    Directory of Open Access Journals (Sweden)

    Wei Li

    2016-05-01

    Full Text Available The investigation of various aspects of the wave climate at a wave energy test site is essential for the development of reliable and efficient wave energy conversion technology. This paper presents studies of the wave climate based on nine years of wave observations from the 2005–2013 period measured with a wave measurement buoy at the Lysekil wave energy test site located off the west coast of Sweden. A detailed analysis of the wave statistics is investigated to reveal the characteristics of the wave climate at this specific test site. The long-term extreme waves are estimated from applying the Peak over Threshold (POT method on the measured wave data. The significant wave height and the maximum wave height at the test site for different return periods are also compared. In this study, a new approach using a mixed-distribution model is proposed to describe the long-term behavior of the significant wave height and it shows an impressive goodness of fit to wave data from the test site. The mixed-distribution model is also applied to measured wave data from four other sites and it provides an illustration of the general applicability of the proposed model. The methodologies used in this paper can be applied to general wave climate analysis of wave energy test sites to estimate extreme waves for the survivability assessment of wave energy converters and characterize the long wave climate to forecast the wave energy resource of the test sites and the energy production of the wave energy converters.

  5. Climate Change Scenarios of Precipitation Extremes in the Carpathian Region Based on an Ensemble of Regional Climate Models

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    Ladislav Gaál

    2014-01-01

    Full Text Available The study examines projected changes in precipitation extremes, aggregated on several time scales (1 hour, 1 day, and 5 days, in simulations of 12 regional climate models (RCMs with high spatial resolution (~25 km. The study area is the Carpathian Basin (Central and Southeastern Europe which has a complex topography and encompasses the whole territory of Slovakia and Hungary as well as major parts of Romania and western Ukraine. We focus on changes in mean seasonal maxima and high quantiles (50-year return values projected for the late 21st century (time slice 2070–2099 in comparison to the control period (time slice 1961–1990, for summer and winter. The 50-year return values are estimated by means of a regional frequency analysis based on the region-of-influence method, which reduces random variability and leads to more reliable estimates of high quantiles. In winter, all examined characteristics of precipitation (seasonal totals, mean seasonal maxima, and 50-year return values for both short-term and multi-day aggregations show similar patterns of projected increases for the late 21st century. In summer, by contrast, drying is projected for seasonal totals in all RCMs while increases clearly prevail for the 50-year return values. The projected increases are larger for short-term (hourly extremes that are more directly related to convective activity than multiday extremes. This suggests that the probability of occurrence of flash floods may increase more than that of large-scale floods in a warmer climate. The within-ensemble variability (and associated uncertainty is, nevertheless, much larger in summer than in winter.

  6. Winter climate extremes and their role for priming SOM decomposition under the snow

    Science.gov (United States)

    Gavazov, Konstantin; Bahn, Michael

    2015-04-01

    The central research question of this project is how soil respiration and soil microbial community composition and activity of subalpine grasslands are affected by extreme winter climate events, such as mid-winter snowmelt and subsequent advanced growing season date. In the scope of this talk, focus will be laid on the assumptions that (1) reduced snow cover leads to intensive freeze-thaw cycles in the soil with larger amplitudes of microbial biomass, DOC and soil CO2 production and efflux over the course of winter, and shifts peak microbial activity to deeper soil layers with limited and recalcitrant substrate; (2) causes a shift in microbial community composition towards decreased fungal/bacterial ratios; and (3) results in a stronger incorporation of labile C in microbial biomass and more pronounced priming effects of soil organic matter turnover. Our findings indicate that snow removal, induces a strong and immediate negative effect on the physiology of soil microbes, impairing them in their capacity for turnover of SOM in the presence of labile substances (priming). This effect however is transient and soil microbes recover within the same winter. The reason for that is that snow removal did not produce any measurable (PLFA) changes in soil microbial community composition. The advanced start of the growing season, as a result of snow removal in mid-winter, granted the bacterial part of the microbial community more active in the uptake of labile substrates and the turnover of SOM than the fungal one. This finding is in line with the concept for a seasonal shift towards bacterial-dominated summer microbial community composition and could bring about implications for the plant-microbe competition for resources at the onset of the growing season.

  7. Evolution of extreme temperature events in short term climate projection for Iberian Peninsula.

    Science.gov (United States)

    Rodriguez, Alfredo; Tarquis, Ana M.; Sanchez, Enrique; Dosio, Alessandro; Ruiz-Ramos, Margarita

    2014-05-01

    Extreme events of maximum and minimum temperatures are a main hazard for agricultural production in Iberian Peninsula. For this purpose, in this study we analyze projections of their evolution that could be valid for the next decade, represented in this study by the 30-year period 2004-2034 (target period). For this purpose two kinds of data were used in this study: 1) observations from the station network of AEMET (Spanish National Meteorological Agency) for five Spanish locations, and 2) simulated data at a resolution of 50 ×50 km horizontal grid derived from the outputs of twelve Regional Climate Models (RCMs) taken from project ENSEMBLES (van der Linden and Mitchell, 2009), with a bias correction (Dosio and Paruolo, 2011; Dosio et al., 2012) regarding the observational dataset Spain02 (Herrera et al., 2012). To validate the simulated climate, the available period of observations was compared to a baseline period (1964-1994) of simulated climate for all locations. Then, to analyze the changes for the present/very next future, probability of extreme temperature events for 2004-2034 were compared to that of the baseline period. Although only minor changes are expected, small variations in variability may have a significant impact in crop performance. The objective of the work is to evaluate the utility of these short term projections for potential users, as for instance insurance companies. References Dosio A. and Paruolo P., 2011. Bias correction of the ENSEMBLES high-resolution climate change projections for use by impact models: Evaluation on the present climate. Journal of Geophysical Research, VOL. 116,D16106, doi:10.1029/2011JD015934 Dosio A., Paruolo P. and Rojas R., 2012. Bias correction of the ENSEMBLES high resolution climate change projections for use by impact models: Analysis of the climate change signal. Journal of Geophysical Research,Volume 117, D17, doi: 0.1029/2012JD017968 Herrera et. al. (2012) Development and Analysis of a 50 year high

  8. Ensuring Resilience of Natural Resources under Exposure to Extreme Climate Events

    Directory of Open Access Journals (Sweden)

    Brent Jacobs

    2016-06-01

    Full Text Available Natural resources directly support rural livelihoods and underpin much of the wealth of rural and regional Australia. Climate change manifesting as increasing frequency and or severity of extreme weather events poses a threat to sustainable management of natural resources because the recurrence of events may exceed the resilience of natural systems or the coping capacity of social systems. We report the findings of a series of participatory workshops with communities in eight discrete landscapes in South East New South Wales, Australia. The workshops focused on how natural resource management (NRM is considered in the Prevent-Prepare-Respond-Recover emergency management cycle. We found that NRM is generally considered only in relation to the protection of life and property and not for the intrinsic value of ecosystem services that support communities. We make three recommendations to improve NRM under extreme climate events. Firstly, the support to communities offered by emergency management agencies could be bolstered by guidance material co-produced with government NR agencies. Secondly, financial assistance from government should specifically target the restoration and maintenance of green infrastructure to avoid loss of social-ecological resilience. Thirdly, action by natural resource dependent communities should be encouraged and supported to better protect ecosystem services in preparation for future extreme events.

  9. An ensemble study of extreme North Sea storm surges in a changing climate

    Directory of Open Access Journals (Sweden)

    A. Sterl

    2009-05-01

    Full Text Available The height of storm surges is extremely important for a low-lying country like the Netherlands. By law, part of the coastal defence system has to withstand a water level that on average occurs only once every 10 000 years. The question then arises whether and how climate change affects the heights of extreme storm surges. Published research points to only small changes. However, due to the limited amount of data available results are usually limited to relatively frequent extremes like the annual 99%-ile. We here report on results from a 17-member ensemble of North Sea water levels spaning the period 1950–2100. It was created by forcing a surge model of the North Sea with meteorological output from a state-of-the-art global climate model which has been driven by greenhouse gas emissions following the SRES A1b scenario. The large ensemble size enables us to calculate 10 000 year return water levels with a low statistical uncertainty. We find no statistically significant change in the 10 000 year return values of surge heights along the Dutch during the 21st century. Also a higher sea level resulting from global warming does not impact the height of the storm surges. As a side effect of our simulations we also obtain results on the interplay between surge and tide.

  10. Climate change and probabilistic scenario of streamflow extremes in an alpine region

    Science.gov (United States)

    Yang, Tao; Wang, Xiaoyan; Yu, Zhongbo; Krysanova, Valentina; Chen, Xi; Schwartz, Franklin W.; Sudicky, Edward A.

    2014-07-01

    Future projections of streamflow extremes are of paramount significance in assessing the climate impacts on social and natural systems, particularly for the Himalayan alpine region in the Tibetan Plateau known as the Asian water tower. This study strives to quantify the uncertainties from different sources in simulating future extreme flows and seeks to construct reliable scenarios of future extreme flows for the headwater catchment of the Yellow River Basin in the 21st century. The results can be formulated as follows: (1) The revised snow model based on a daily active temperature method is superior to the commonly used degree-day method in simulating snowmelt processes. (2) In general, hydrological models contribute more uncertainties than the downscaling methods in high flow and low flow over the cryospheric alpine regions characterized by the snow-rainfall-induced runoff processes under most scenarios. Meanwhile, impacts to uncertainty vary with time. (3) The ultimate probability of high flow exhibits a downward trend in future by using an unconditional method, whereas positive changes in the probability of low flow are projected. The method in the work includes a variety of influence from different contributing factors (e.g., downscaling models, hydrological models, model parameters, and their simulation skills) on streamflow projection, therefore can offer more information (i.e., different percentiles of flow and uncertainty ranges) for future water resource planning compared with the purely deterministic approaches. Hence, the results are beneficial to boost our current methodologies of climate impact research in the Himalayan alpine zone.

  11. Climate change and probabilistic scenario of streamflow extremes in a cryospheric alpine region

    Science.gov (United States)

    Yang, Tao; Gao, Cheng

    2015-04-01

    Future projections of streamflow extremes are of paramount significance in assessing the climate impacts on social and natural systems, particularly for the Himalayan alpine region in the Tibetan Plateau known as the Asian Water Tower. This study strives to quantify the uncertainties from different sources in simulating future extreme flows and seeks to construct reliable scenarios of future extreme flows for the headwater catchment of the Yellow River Basin in the 21st century. The results can be formulated as follows: (1) The revised snow model based on a daily active temperature method is superior to the commonly used degree-day method in simulating snowmelt processes. (2) In general, hydrological models contribute more uncertainties than the downscaling methods in high flow and low flow over the cryospheric alpine regions characterized by the snow-rainfall induced runoff processes under most scenarios. Meanwhile, impacts to uncertainty vary with time. (3) The ultimate probability of high-flow exhibits a downward trend in future by using an unconditional method, whereas positive changes in probability of low-flow are projected. The method in the work includes a variety of influence from different contributing factors (e.g. downscaling models, hydrological models, model parameters, and their simulation skills) on streamflow projection, therefore can offer more information (i.e. different percentiles of flow and uncertainty ranges) for future water resources planning compared with the purely deterministic approaches. Hence, the results are beneficial to boost our current methodologies of climate impact research in the Himalayan alpine zone.

  12. Comparing regional precipitation and temperature extremes in climate model and reanalysis products

    Directory of Open Access Journals (Sweden)

    Oliver Angélil

    2016-09-01

    Full Text Available A growing field of research aims to characterise the contribution of anthropogenic emissions to the likelihood of extreme weather and climate events. These analyses can be sensitive to the shapes of the tails of simulated distributions. If tails are found to be unrealistically short or long, the anthropogenic signal emerges more or less clearly, respectively, from the noise of possible weather. Here we compare the chance of daily land-surface precipitation and near-surface temperature extremes generated by three Atmospheric Global Climate Models typically used for event attribution, with distributions from six reanalysis products. The likelihoods of extremes are compared for area-averages over grid cell and regional sized spatial domains. Results suggest a bias favouring overly strong attribution estimates for hot and cold events over many regions of Africa and Australia, and a bias favouring overly weak attribution estimates over regions of North America and Asia. For rainfall, results are more sensitive to geographic location. Although the three models show similar results over many regions, they do disagree over others. Equally, results highlight the discrepancy amongst reanalyses products. This emphasises the importance of using multiple reanalysis and/or observation products, as well as multiple models in event attribution studies.

  13. Comparing regional precipitation and temperature extremes in climate model and reanalysis products.

    Science.gov (United States)

    Angélil, Oliver; Perkins-Kirkpatrick, Sarah; Alexander, Lisa V; Stone, Dáithí; Donat, Markus G; Wehner, Michael; Shiogama, Hideo; Ciavarella, Andrew; Christidis, Nikolaos

    2016-09-01

    A growing field of research aims to characterise the contribution of anthropogenic emissions to the likelihood of extreme weather and climate events. These analyses can be sensitive to the shapes of the tails of simulated distributions. If tails are found to be unrealistically short or long, the anthropogenic signal emerges more or less clearly, respectively, from the noise of possible weather. Here we compare the chance of daily land-surface precipitation and near-surface temperature extremes generated by three Atmospheric Global Climate Models typically used for event attribution, with distributions from six reanalysis products. The likelihoods of extremes are compared for area-averages over grid cell and regional sized spatial domains. Results suggest a bias favouring overly strong attribution estimates for hot and cold events over many regions of Africa and Australia, and a bias favouring overly weak attribution estimates over regions of North America and Asia. For rainfall, results are more sensitive to geographic location. Although the three models show similar results over many regions, they do disagree over others. Equally, results highlight the discrepancy amongst reanalyses products. This emphasises the importance of using multiple reanalysis and/or observation products, as well as multiple models in event attribution studies.

  14. Modeling nonstationary extreme wave heights in present and future climate of Greek Seas

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    Panagiota Galiatsatou

    2016-01-01

    Full Text Available In this study the generalized extreme value (GEV distribution function was used to assess nonstationarity in annual maximum wave heights for selected locations in the Greek Seas, both in the present and future climate. The available significant wave height data were divided into groups corresponding to the present period (1951 to 2000, a first future period (2001 to 2050, and a second future period (2051 to 2100. For each time period, the parameters of the GEV distribution were specified as functions of time-varying covariates and estimated using the conditional density network (CDN. For each location and selected time period, a total number of 29 linear and nonlinear models were fitted to the wave data, for a given combination of covariates. The covariates used in the GEV-CDN models consisted of wind fields resulting from the Regional Climate Model version 3 (RegCM3 developed by the International Center for Theoritical Physics (ICTP with a spatial resolution of 10 km × 10 km, after being processed using principal component analysis (PCA. The results obtained from the best fitted models in the present and future periods for each location were compared, revealing different patterns of relationships between wind components and extreme wave height quantiles in different parts of the Greek Seas and different periods. The analysis demonstrates an increase of extreme wave heights in the first future period as compared with the present period, causing a significant threat to Greek coastal areas in the North Aegean Sea and the Ionian Sea.

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

    Science.gov (United States)

    Schulz, Karsten; Bernhardt, Matthias

    2016-04-01

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

  16. Vulnerability to extreme heat and climate change: is ethnicity a factor?

    Science.gov (United States)

    Hansen, Alana; Bi, Linda; Saniotis, Arthur; Nitschke, Monika

    2013-07-29

    With a warming climate, it is important to identify sub-populations at risk of harm during extreme heat. Several international studies have reported that individuals from ethnic minorities are at increased risk of heat-related illness, for reasons that are not often discussed. The aim of this article is to investigate the underpinning reasons as to why ethnicity may be associated with susceptibility to extreme heat, and how this may be relevant to Australia's population. Drawing upon literary sources, the authors provide commentary on this important, yet poorly understood area of heat research. Social and economic disparities, living conditions, language barriers, and occupational exposure are among the many factors contributing to heat-susceptibility among minority ethnic groups in the United States. However, there is a knowledge gap about socio-cultural influences on vulnerability in other countries. More research needs to be undertaken to determine the effects of heat on tourists, migrants, and refugees who are confronted with a different climatic environment. Thorough epidemiological investigations of the association between ethnicity and heat-related health outcomes are required, and this could be assisted with better reporting of nationality data in health statistics. Climate change adaptation strategies in Australia and elsewhere need to be ethnically inclusive and cognisant of an upward trend in the proportion of the population who are migrants and refugees.

  17. Preface: Monitoring and modelling to guide coastal adaptation to extreme storm events in a changing climate

    Science.gov (United States)

    Brown, J. M.; Ciavola, P.; Masselink, G.; McCall, R.; Plater, A. J.

    2016-02-01

    Storms across the globe and their associated consequences in coastal zones (flooding and erosion), combined with the long-term geomorphic evolution of our coastlines, are a threat to life and assets, both socioeconomic and environmental. In a changing climate, with a rising global sea level, potentially changing patterns in storm tracks and storminess, and rising population density and pressures on the coastal zone, the future risk of coastal storm impacts is likely to increase. Coastal managers and policy makers therefore need to make effective and timely decisions on the use of resources for the immediate and longer Research focused on "monitoring and modelling to guide coastal adaptation to extreme storm events in a changing climate" is becoming more common; its goal is to provide science-based decision support for effective adaptation to the consequences of storm impacts, both now and under future climate scenarios at the coast. The growing transfer of information between the science community and end-users is enabling leading research to have a greater impact on the socioeconomic resilience of coastal communities. This special issue covers recent research activities relating to coastal hazard mapping in response to extreme events, economic impacts of long-term change, coastal processes influencing management decisions and the development of online decision support tools.

  18. Vulnerability to extreme heat and climate change: is ethnicity a factor?

    Directory of Open Access Journals (Sweden)

    Alana Hansen

    2013-07-01</