WorldWideScience

Sample records for extreme heat events

  1. Predicting Indoor Heat Exposure Risk during Extreme Heat Events

    Science.gov (United States)

    Quinn, Ashlinn; Tamerius, James D.; Perzanowski, Matthew; Jacobson, Judith S.; Goldstein, Inge; Acosta, Luis; Shaman, Jeffrey

    2014-01-01

    Increased heat-related morbidity and mortality are expected direct consequences of global warming. In the developed world, most fatal heat exposures occur in the indoor home environment, yet little is known of the correspondence between outdoor and indoor heat. Here we show how summertime indoor heat and humidity measurements from 285 low- and middle-income New York City homes vary as a function of concurrent local outdoor conditions. Indoor temperatures and heat index levels were both found to have strong positive linear associations with their outdoor counterparts; however, among the sampled homes a broad range of indoor conditions manifested for the same outdoor conditions. Using these models, we simulated indoor conditions for two extreme events: the 10-day 2006 NYC heat wave and a 9-day event analogous to the more extreme 2003 Paris heat wave. These simulations indicate that many homes in New York City would experience dangerously high indoor heat index levels during extreme heat events. These findings also suggest that increasing numbers of NYC low- and middle-income households will be exposed to heat index conditions above important thresholds should the severity of heat waves increase with global climate change. The study highlights the urgent need for improved indoor temperature and humidity management. PMID:24893319

  2. Attribution of Extreme Heat Event Using a Seasonal Forecast Framework

    Science.gov (United States)

    Wang, Guomin; Hope, Pandora; Lim, Eun-Pa; Hendon, Harry; Arblaster, Julie

    2017-04-01

    Here we present a method for the attribution of extreme climate events using an initialised climate prediction system to attribute the degree of influence from increasing levels of atmospheric carbon dioxide (CO2) on an extreme event. The initial-value nature of our method allows little time for the growth of model-driven biases, while allowing the full coupled response of the ocean-atmosphere-land system. To illustrate the use of this method, we attribute the causes of two recent month long record heat events that occurred in October 2014 and 2015 over Australia. The events were forecast twice, one initialised with real world analysed ocean-land-atmosphere states and current CO2 concentration and another with altered ocean-land-atmosphere states corresponding to a counterfactual world with low CO2. We find that relative to the climatology with CO2 level of 1960, at least half of the heat anomaly forecasted across Australia in the two events can be attributed to global warming associated with increased CO2. Additional sensitivity experiments were conducted to assess the impact of the internal climate drivers on the events. The sensitivity experiment results suggest that the atmospheric circulation anomalies played a more important role than the direct impact from the ocean in promoting extreme heat across Australia.

  3. A Review of Recent Advances in Research on Extreme Heat Events

    Science.gov (United States)

    Horton, Radley M.; Mankin, Justin S.; Lesk, Corey; Coffel, Ethan; Raymond, Colin

    2016-01-01

    Reviewing recent literature, we report that changes in extreme heat event characteristics such as magnitude, frequency, and duration are highly sensitive to changes in mean global-scale warming. Numerous studies have detected significant changes in the observed occurrence of extreme heat events, irrespective of how such events are defined. Further, a number of these studies have attributed present-day changes in the risk of individual heat events and the documented global-scale increase in such events to anthropogenic-driven warming. Advances in process-based studies of heat events have focused on the proximate land-atmosphere interactions through soil moisture anomalies, and changes in occurrence of the underlying atmospheric circulation associated with heat events in the mid-latitudes. While evidence for a number of hypotheses remains limited, climate change nevertheless points to tail risks of possible changes in heat extremes that could exceed estimates generated from model outputs of mean temperature. We also explore risks associated with compound extreme events and nonlinear impacts associated with extreme heat.

  4. Impact of Extreme Heat Events on Emergency Department Visits in North Carolina (2007-2011).

    Science.gov (United States)

    Fuhrmann, Christopher M; Sugg, Margaret M; Konrad, Charles E; Waller, Anna

    2016-02-01

    Extreme heat is the leading cause of weather-related mortality in the U.S. Extreme heat also affects human health through heat stress and can exacerbate underlying medical conditions that lead to increased morbidity and mortality. In this study, data on emergency department (ED) visits for heat-related illness (HRI) and other selected diseases were analyzed during three heat events across North Carolina from 2007 to 2011. These heat events were identified based on the issuance and verification of heat products from local National Weather Service forecast offices (i.e. Heat Advisory, Heat Watch, and Excessive Heat Warning). The observed number of ED visits during these events were compared to the expected number of ED visits during several control periods to determine excess morbidity resulting from extreme heat. All recorded diagnoses were analyzed for each ED visit, thereby providing insight into the specific pathophysiological mechanisms and underlying health conditions associated with exposure to extreme heat. The most common form of HRI was heat exhaustion, while the percentage of visits with heat stroke was relatively low (65 years of age) were at greatest risk for HRI during the early summer heat event (8.9 visits per 100,000), while young and middle age adults (18-44 years of age) were at greatest risk during the mid-summer event (6.3 visits per 100,000). Many of these visits were likely due to work-related exposure. The most vulnerable demographic during the late summer heat event was adolescents (15-17 years of age), which may relate to the timing of organized sports. This demographic also exhibited the highest visit rate for HRI among all three heat events (10.5 visits per 100,000). Significant increases (p events (3-8%). The greatest increases were found in visits with hypotension during the late summer event (23%) and sequelae during the early summer event (30%), while decreases were noted for visits with hemorrhagic stroke during the middle and late

  5. Heat-related deaths after an extreme heat event--four states, 2012, and United States, 1999-2009.

    Science.gov (United States)

    2013-06-07

    On June 29, 2012, a rapidly moving line of intense thunderstorms with high winds swept across the midwestern and eastern United States, causing widespread damage and power outages. Afterward, the area experienced extreme heat, with maximum temperatures exceeding 100°F (37.8°C). This report describes 32 heat-related deaths in Maryland, Ohio, Virginia, and West Virginia that occurred during the 2 weeks following the storms and power outages. Median age of the decedents was 65 years, and most of the excessive heat exposures occurred within homes. During 1999-2009, an annual average of 658 heat-related deaths occurred in the United States. Heat-related deaths are preventable, and heat response plans should be in place before an extreme heat event (EHE). Interventions should focus on identifying and limiting heat exposure among vulnerable populations.

  6. Climate change increases the likelihood of catastrophic avian mortality events during extreme heat waves.

    Science.gov (United States)

    McKechnie, Andrew E; Wolf, Blair O

    2010-04-23

    Severe heat waves have occasionally led to catastrophic avian mortality in hot desert environments. Climate change models predict increases in the intensity, frequency and duration of heat waves. A model of avian evaporative water requirements and survival times during the hottest part of day reveals that the predicted increases in maximum air temperatures will result in large fractional increases in water requirements (in small birds, equivalent to 150-200 % of current values), which will severely reduce survival times during extremely hot weather. By the 2080s, desert birds will experience reduced survival times much more frequently during mid-summer, increasing the frequency of catastrophic mortality events.

  7. Strategies to Reduce the Harmful Effects of Extreme Heat Events: A Four-City Study

    Directory of Open Access Journals (Sweden)

    Jalonne L. White-Newsome

    2014-02-01

    Full Text Available Extreme heat events (EHEs are becoming more intense, more frequent and longer lasting in the 21st century. These events can disproportionately impact the health of low-income, minority, and urban populations. To better understand heat-related intervention strategies used by four U.S. cities, we conducted 73 semi-structured interviews with government and non-governmental organization leaders representing public health, general social services, emergency management, meteorology, and the environmental planning sectors in Detroit, MI; New York City, NY; Philadelphia, PA and Phoenix, AZ—cities selected for their diverse demographics, climates, and climate adaptation strategies. We identified activities these leaders used to reduce the harmful effects of heat for residents in their city, as well as the obstacles they faced and the approaches they used to evaluate these efforts. Local leaders provided a description of how local context (e.g., climate, governance and city structure impacted heat preparedness. Despite the differences among study cities, political will and resource access were critical to driving heat-health related programming. Upon completion of our interviews, we convened leaders in each city to discuss these findings and their ongoing efforts through day-long workshops. Our findings and the recommendations that emerged from these workshops could inform other local or national efforts towards preventing heat-related morbidity and mortality.

  8. Strategies to reduce the harmful effects of extreme heat events: a four-city study.

    Science.gov (United States)

    White-Newsome, Jalonne L; McCormick, Sabrina; Sampson, Natalie; Buxton, Miatta A; O'Neill, Marie S; Gronlund, Carina J; Catalano, Linda; Conlon, Kathryn C; Parker, Edith A

    2014-02-13

    Extreme heat events (EHEs) are becoming more intense, more frequent and longer lasting in the 21st century. These events can disproportionately impact the health of low-income, minority, and urban populations. To better understand heat-related intervention strategies used by four U.S. cities, we conducted 73 semi-structured interviews with government and non-governmental organization leaders representing public health, general social services, emergency management, meteorology, and the environmental planning sectors in Detroit, MI; New York City, NY; Philadelphia, PA and Phoenix, AZ-cities selected for their diverse demographics, climates, and climate adaptation strategies. We identified activities these leaders used to reduce the harmful effects of heat for residents in their city, as well as the obstacles they faced and the approaches they used to evaluate these efforts. Local leaders provided a description of how local context (e.g., climate, governance and city structure) impacted heat preparedness. Despite the differences among study cities, political will and resource access were critical to driving heat-health related programming. Upon completion of our interviews, we convened leaders in each city to discuss these findings and their ongoing efforts through day-long workshops. Our findings and the recommendations that emerged from these workshops could inform other local or national efforts towards preventing heat-related morbidity and mortality.

  9. Extreme Heat

    Science.gov (United States)

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  10. A Novel Web Application to Analyze and Visualize Extreme Heat Events

    Science.gov (United States)

    Li, G.; Jones, H.; Trtanj, J.

    2016-12-01

    Extreme heat is the leading cause of weather-related deaths in the United States annually and is expected to increase with our warming climate. However, most of these deaths are preventable with proper tools and services to inform the public about heat waves. In this project, we have investigated the key indicators of a heat wave, the vulnerable populations, and the data visualization strategies of how those populations most effectively absorb heat wave data. A map-based web app has been created that allows users to search and visualize historical heat waves in the United States incorporating these strategies. This app utilizes daily maximum temperature data from NOAA Global Historical Climatology Network which contains about 2.7 million data points from over 7,000 stations per year. The point data are spatially aggregated into county-level data using county geometry from US Census Bureau and stored in Postgres database with PostGIS spatial capability. GeoServer, a powerful map server, is used to serve the image and data layers (WMS and WFS). The JavaScript-based web-mapping platform Leaflet is used to display the temperature layers. A number of functions have been implemented for the search and display. Users can search for extreme heat events by county or by date. The "by date" option allows a user to select a date and a Tmax threshold which then highlights all of the areas on the map that meet those date and temperature parameters. The "by county" option allows the user to select a county on the map which then retrieves a list of heat wave dates and daily Tmax measurements. This visualization is clean, user-friendly, and novel because while this sort of time, space, and temperature measurements can be found by querying meteorological datasets, there does not exist a tool that neatly packages this information together in an easily accessible and non-technical manner, especially in a time where climate change urges a better understanding of heat waves.

  11. Contribution of urbanization to the increase of extreme heat events in an urban agglomeration in east China

    Science.gov (United States)

    Yang, Xuchao; Ruby Leung, L.; Zhao, Naizhuo; Zhao, Chun; Qian, Yun; Hu, Kejia; Liu, Xiaoping; Chen, Baode

    2017-07-01

    The urban agglomeration of Yangtze River Delta (YRD) is emblematic of China's rapid urbanization during the past decades. Based on homogenized daily maximum and minimum temperature data, the contributions of urbanization to trends of summer extreme temperature indices (ETIs) in YRD are evaluated. Dynamically classifying the observational stations into urban and rural, this study presents unexplored changes in temperature extremes during the past four decades in YRD and quantifies the amplification of the positive trends in ETIs by the urban heat island effect. Overall, urbanization contributes to more than one third of the increase of intensity of extreme heat events in the region, which is comparable to the contribution of greenhouse gases. Compared to rural stations, more notable shifts to the right in the probability distribution of temperature and ETIs are found in urban stations. The rapid urbanization in YRD has resulted in large increases in the risk of heat extremes.

  12. Enhancing Resilience to Heat Extremes: Multi-model Forecasting of Excessive Heat Events at Subseasonal Lead Times

    Science.gov (United States)

    Vintzileos, A.; Halpert, M.; Gottschalk, J.; Allgood, A.

    2016-12-01

    Heatwaves are among the most dangerous, yet invisible, of natural hazards. According to NOAA, the distribution of 30-year based annual mean fatalities from natural hazards in the U.S. ranks as follows; those from heat (130), floods (81), tornadoes (70), lightning (48) and hurricanes (46). Early warning to excessive heat events can be improved by using multi-scale prognostic systems. We designed and developed such a system for forecasting excessive heat events at lead times beyond Week-1. This Subseasonal Excessive Heat Outlook System (SEHOS) consists of (a) a monitoring/verification component and (b) a forecasting component which in its baseline version uses NOAA's Global Ensemble Forecast System (GEFS) predictions of temperature and humidity from Day-8 to Day-14. In this presentation, we discuss the definition of heat events, sources of predictability and present the forecast skill of SEHOS for the GEFS reforecast period (1985-2014). We then use subseasonal reforecasts from several models from the S2S database and discuss the forecast value added by multi-model approaches in predicting excessive heat events.

  13. Analysis of extreme events

    CSIR Research Space (South Africa)

    Khuluse, S

    2009-04-01

    Full Text Available ) determination of the distribution of the damage and (iii) preparation of products that enable prediction of future risk events. The methodology provided by extreme value theory can also be a powerful tool in risk analysis...

  14. Simulation of extreme rainfall event of November 2009 over Jeddah, Saudi Arabia: the explicit role of topography and surface heating

    Science.gov (United States)

    Almazroui, Mansour; Raju, P. V. S.; Yusef, A.; Hussein, M. A. A.; Omar, M.

    2017-02-01

    In this paper, a nonhydrostatic Weather Research and Forecasting (WRF) model has been used to simulate the extreme precipitation event of 25 November 2009, over Jeddah, Saudi Arabia. The model is integrated in three nested (27, 9, and 3 km) domains with the initial and boundary forcing derived from the NCEP reanalysis datasets. As a control experiment, the model integrated for 48 h initiated at 0000 UTC on 24 November 2009. The simulated rainfall in the control experiment depicts in well agreement with Tropical Rainfall Measurement Mission rainfall estimates in terms of intensity as well as spatio-temporal distribution. Results indicate that a strong low-level (850 hPa) wind over Jeddah and surrounding regions enhanced the moisture and temperature gradient and created a conditionally unstable atmosphere that favored the development of the mesoscale system. The influences of topography and heat exchange process in the atmosphere were investigated on the development of extreme precipitation event; two sensitivity experiments are carried out: one without topography and another without exchange of surface heating to the atmosphere. The results depict that both surface heating and topography played crucial role in determining the spatial distribution and intensity of the extreme rainfall over Jeddah. The topography favored enhanced uplift motion that further strengthened the low-level jet and hence the rainfall over Jeddah and adjacent areas. On the other hand, the absence of surface heating considerably reduced the simulated rainfall by 30% as compared to the observations.

  15. Human-biometeorological assessment of increasing summertime extreme heat events in Shanghai, China during 1973-2015

    Science.gov (United States)

    Kong, Qinqin; Ge, Quansheng; Xi, Jianchao; Zheng, Jingyun

    2016-09-01

    Summertime extreme heat events, defined by the Universal Thermal Climate Index (UTCI), have shown increasing trends in Shanghai from 1973 to 2015. There is a clear shift to higher temperatures for the daily maximum UTCI values, and the number of days with daily maximum UTCI exceeding 38 °C significantly increased by 4.34 days/10a. An upward trend of 3.67 days/10a was detected for the number of hot days which also displays an abrupt increase around 1998. Both the frequency and total duration of heat waves have significantly increased by 0.77 times/10a and 3.51 days/10a respectively. Their inter-decadal variations indicate a three-part division of the study period showing more and more heat waves and longer total duration, which are 1.0 times/a and 4.13 days/a for 1973-1987, 1.71 times/a and 7.64 days/a for 1988-2001, and 3.57 times/a and 16.0 days/a for 2002-2015. In addition to that are more occurrences of long-lasting heat waves. Compared with the UTCI, air temperature-based definitions have indicated substantially higher increases in extreme heat events, especially for hot nights. The relatively low humidity and strong wind speeds in the twenty-first century are considered to be responsible for this difference. Our study provides a more in-depth case to monitor extreme heat events under the combining effects of air temperature, humidity, wind speeds, total cloud cover, etc. and can support studies over other regions.

  16. Management adaptation of invertebrate fisheries to an extreme marine heat wave event at a global warming hot spot.

    Science.gov (United States)

    Caputi, Nick; Kangas, Mervi; Denham, Ainslie; Feng, Ming; Pearce, Alan; Hetzel, Yasha; Chandrapavan, Arani

    2016-06-01

    An extreme marine heat wave which affected 2000 km of the midwest coast of Australia occurred in the 2010/11 austral summer, with sea-surface temperature (SST) anomalies of 2-5°C above normal climatology. The heat wave was influenced by a strong Leeuwin Current during an extreme La Niña event at a global warming hot spot in the Indian Ocean. This event had a significant effect on the marine ecosystem with changes to seagrass/algae and coral habitats, as well as fish kills and southern extension of the range of some tropical species. The effect has been exacerbated by above-average SST in the following two summers, 2011/12 and 2012/13. This study examined the major impact the event had on invertebrate fisheries and the management adaption applied. A 99% mortality of Roei abalone (Haliotis roei) and major reductions in recruitment of scallops (Amusium balloti), king (Penaeus latisulcatus) and tiger (P. esculentus) prawns, and blue swimmer crabs were detected with management adapting with effort reductions or spatial/temporal closures to protect the spawning stock and restocking being evaluated. This study illustrates that fisheries management under extreme temperature events requires an early identification of temperature hot spots, early detection of abundance changes (preferably using pre-recruit surveys), and flexible harvest strategies which allow a quick response to minimize the effect of heavy fishing on poor recruitment to enable protection of the spawning stock. This has required researchers, managers, and industry to adapt to fish stocks affected by an extreme environmental event that may become more frequent due to climate change.

  17. Development of heat and drought related extreme weather events and their effect on winter wheat yields in Germany

    Science.gov (United States)

    Lüttger, Andrea B.; Feike, Til

    2017-02-01

    Climate change constitutes a major challenge for high productivity in wheat, the most widely grown crop in Germany. Extreme weather events including dry spells and heat waves, which negatively affect wheat yields, are expected to aggravate in the future. It is crucial to improve the understanding of the spatiotemporal development of such extreme weather events and the respective crop-climate relationships in Germany. Thus, the present study is a first attempt to evaluate the historic development of relevant drought and heat-related extreme weather events from 1901 to 2010 on county level (NUTS-3) in Germany. Three simple drought indices and two simple heat stress indices were used in the analysis. A continuous increase in dry spells over time was observed over the investigated periods from 1901-1930, 1931-1960, 1961-1990 to 2001-2010. Short and medium dry spells, i.e., precipitation-free periods longer than 5 and 8 days, respectively, increased more strongly compared to longer dry spells (longer than 11 days). The heat-related stress indices with maximum temperatures above 25 and 28 °C during critical wheat growth phases showed no significant increase over the first three periods but an especially sharp increase in the final 1991-2010 period with the increases being particularly pronounced in parts of Southwestern Germany. Trend analysis over the entire 110-year period using Mann-Kendall test revealed a significant positive trend for all investigated indices except for heat stress above 25 °C during flowering period. The analysis of county-level yield data from 1981 to 2010 revealed declining spatial yield variability and rather constant temporal yield variability over the three investigated (1981-1990, 1991-2000, and 2001-2010) decades. A clear spatial gradient manifested over time with variability in the West being much smaller than in the east of Germany. Correlating yield variability with the previously analyzed extreme weather indices revealed strong

  18. The Spanish tourist sector facing extreme climate events: a case study of domestic tourism in the heat wave of 2003

    Science.gov (United States)

    Gómez-Martín, M. Belén; Armesto-López, Xosé A.; Martínez-Ibarra, Emilio

    2014-07-01

    This research explores, by means of a questionnaire-based survey, public knowledge and perception as well as the behaviour of young Spanish tourists before, during and after the summer holiday period affected by an episode of extreme heat in 2003. The survey was administered between November and December 2004. The extraordinary heat wave of the summer of 2003 can be seen as an example of a normal episode in terms of the predicted intensity and duration of European summers towards the end of the twenty-first century. It can therefore be used as the laboratory setting for this study. In this context, the use of the climate analogue approach allows us to obtain novel perspectives regarding the future impact that this type of event could have on tourist demand, based on a real experience. Likewise, such an approach allows the strategies of adaptation implemented by the different elements in the tourist system in order to cope with the atmospheric episode to be evaluated. Such strategies could prove useful in reducing vulnerability when faced with similar episodes in the future. The main results indicate that Spanish tourists (young segment market) are flexible in adapting to episodes of extremely high temperatures. Their personal perception of the phenomenon, their behaviour and the adaptation measures implemented to a greater or lesser extent before that time, reduce the vulnerability of the sector when faced with this type of event, at least from the point of view of this young segment of the internal national market. In Spain, the episode of extreme heat of 2003 has led to the implementation or improvement of some adaptive measures after the event, especially in the fields of management, policy and education.

  19. The Spanish tourist sector facing extreme climate events: a case study of domestic tourism in the heat wave of 2003.

    Science.gov (United States)

    Gómez-Martín, M Belén; Armesto-López, Xosé A; Martínez-Ibarra, Emilio

    2014-07-01

    This research explores, by means of a questionnaire-based survey, public knowledge and perception as well as the behaviour of young Spanish tourists before, during and after the summer holiday period affected by an episode of extreme heat in 2003. The survey was administered between November and December 2004. The extraordinary heat wave of the summer of 2003 can be seen as an example of a normal episode in terms of the predicted intensity and duration of European summers towards the end of the twenty-first century. It can therefore be used as the laboratory setting for this study. In this context, the use of the climate analogue approach allows us to obtain novel perspectives regarding the future impact that this type of event could have on tourist demand, based on a real experience. Likewise, such an approach allows the strategies of adaptation implemented by the different elements in the tourist system in order to cope with the atmospheric episode to be evaluated. Such strategies could prove useful in reducing vulnerability when faced with similar episodes in the future. The main results indicate that Spanish tourists (young segment market) are flexible in adapting to episodes of extremely high temperatures. Their personal perception of the phenomenon, their behaviour and the adaptation measures implemented to a greater or lesser extent before that time, reduce the vulnerability of the sector when faced with this type of event, at least from the point of view of this young segment of the internal national market. In Spain, the episode of extreme heat of 2003 has led to the implementation or improvement of some adaptive measures after the event, especially in the fields of management, policy and education.

  20. Solar extreme events

    CERN Document Server

    Hudson, Hugh S

    2015-01-01

    Solar flares and CMEs have a broad range of magnitudes. This review discusses the possibility of "extreme events," defined as those with magnitudes greater than have been seen in the existing historical record. For most quantitative measures, this direct information does not extend more than a century and a half into the recent past. The magnitude distributions (occurrence frequencies) of solar events (flares/CMEs) typically decrease with the parameter measured or inferred (peak flux, mass, energy etc. Flare radiation fluxes tend to follow a power law slightly flatter than $S^{-2}$, where S represents a peak flux; solar particle events (SPEs) follow a still flatter power law up to a limiting magnitude, and then appear to roll over to a steeper distribution, which may take an exponential form or follow a broken power law. This inference comes from the terrestrial $^{14}$C record and from the depth dependence of various radioisotope proxies in the lunar regolith and in meteorites. Recently major new observation...

  1. The Influence of green areas and roof albedos on air temperatures during Extreme Heat Events in Berlin, Germany

    Directory of Open Access Journals (Sweden)

    Sebastian Schubert

    2013-04-01

    Full Text Available The mesoscale atmospheric model COSMO-CLM (CCLM with the Double Canyon Effect Parametrization Scheme (DCEP is applied to investigate possible adaption measures to extreme heat events (EHEs for the city of Berlin, Germany. The emphasis is on the effects of a modified urban vegetation cover and roof albedo on near-surface air temperatures. Five EHEs with a duration of 5 days or more are identified for the period 2000 to 2009. A reference simulation is carried out for each EHE with current vegetation cover, roof albedo and urban canopy parameters (UCPs, and is evaluated with temperature observations from weather stations in Berlin and its surroundings. The derivation of the UCPs from an impervious surface map and a 3-D building data set is detailed. Characteristics of the simulated urban heat island for each EHE are analysed in terms of these UCPs. In addition, six sensitivity runs are examined with a modified vegetation cover of each urban grid cell by -25%, 5% and 15%, with a roof albedo increased to 0.40 and 0.65, and with a combination of the largest vegetation cover and roof albedo, respectively. At the weather stations' grid cells, the results show a maximum of the average diurnal change in air temperature during each EHE of 0.82 K and -0.48 K for the -25% and 15% vegetation covers, -0.50 K for the roof albedos of 0.65, and -0.63 K for the combined vegetation and albedo case. The largest effects on the air temperature are detected during midday.

  2. The contribution of urbanization to recent extreme heat events and a potential mitigation strategy in the Beijing-Tianjin-Hebei metropolitan area

    Science.gov (United States)

    Wang, Mingna; Yan, Xiaodong; Liu, Jiyuan; Zhang, Xuezhen

    2013-11-01

    This paper addresses the contribution of urban land use change to near-surface air temperature during the summer extreme heat events of the early twenty-first century in the Beijing-Tianjin-Hebei metropolitan area. This study uses the Weather Research Forecasting model with a single urban canopy model and the newest actual urban cover datasets. The results show that urban land use characteristics that have evolved over the past ~20 years in the Beijing-Tianjin-Hebei metropolitan area have had a significant impact on the extreme temperatures occurring during extreme heat events. Simulations show that new urban development has caused an intensification and expansion of the areas experiencing extreme heat waves with an average increase in temperature of approximately 0.60 °C. This change is most obvious at night with an increase up to 0.95 °C, for which the total contribution of anthropogenic heat is 34 %. We also simulate the effects of geo-engineering strategies increasing the albedo of urban roofs, an effective way of reducing urban heat island, which can reduce the urban mean temperature by approximately 0.51 °C and counter approximately 80 % of the heat wave results from urban sprawl during the last 20 years.

  3. Extreme Energy Events Monitoring report

    CERN Document Server

    Baimukhamedova, Nigina

    2015-01-01

    Following paper reflects the progress I made on Summer Student Program within Extreme Energy Events Monitor project I was working on. During 8 week period I managed to build a simple detector system that is capable of triggering events similar to explosions (sudden change in sound levels) and measuring approximate location of the event. Source codes are available upon request and settings described further.

  4. Contribution of urbanization to the increase of extreme heat events in an urban agglomeration in east China: Urbanization and the Increase of EHEs

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xuchao [Institute of Island and Coastal Ecosystems, Ocean College, Zhejiang University, Zhoushan China; Ruby Leung, L. [Pacific Northwest National Laboratory, Richland Washington USA; Zhao, Naizhuo [Department of Geosciences, Texas Tech University, Lubbock Texas USA; Zhao, Chun [School of Earth and Space Sciences, University of Science and Technology of China, Hefei China; Qian, Yun [Pacific Northwest National Laboratory, Richland Washington USA; Hu, Kejia [Institute of Island and Coastal Ecosystems, Ocean College, Zhejiang University, Zhoushan China; Liu, Xiaoping [School of Geography and Planning, Sun Yat-sen University, Guangzhou China; Chen, Baode [Shanghai Typhoon Institute of China Meteorological Administration, Shanghai China

    2017-07-03

    The urban agglomeration of Yangtze River Delta (YRD) is emblematic of China’s rapid urbanization during the past decades. Based on homogenized daily maximum and minimum temperature data, the contributions of urbanization to trends of extreme temperature indices (ETIs) during summer in YRD are evaluated. Dynamically classifying the observational stations into urban and rural areas, this study presents unexplored changes in temperature extremes during the past four decades in the YRD region and quantifies the amplification of the positive trends in ETIs by the urban heat island effect. Overall, urbanization contributes to more than one third in the increase of intensity of extreme heat events in the region, which is comparable to the contribution of greenhouse gases. Compared to rural stations, more notable shifts to the right in the probability distribution of temperature and ETIs were observed in urban stations.

  5. 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.

  6. The contribution of urbanization to recent extreme heat events and white roof mitigation strategy in the Beijing-Tianjin-Hebei metropolitan area

    Science.gov (United States)

    Wang, Mingna

    2015-04-01

    The UHI effect can aggravate summertime heat waves and strongly influence human comfort and health, leading to greater mortality in metropolitan areas. Many geo-engineering technological strategies have been proposed to mitigate climate warming, and for the UHI, increasing the albedo of artificial urban surfaces (rooftops or pavements) has been considered a lucrative and effective way to cool cities. The objective of this work is to quantify the contribution of urbanization to recent extreme heat events of the early 21st century in the Beijing-Tianjin-Hebei metropolitan area, using the mesoscale WRF model coupled with a single urban canopy model and actual urban land cover datasets. This work also investigates a simulation of the regional effects of white roof technology by increasing the albedo of urban areas in the urban canopy model to mitigate the urban heat island, especially in extreme heat waves. The results show that urban land use characteristics that have evolved over the past ~20 years in the Beijing-Tianjin-Hebei metropolitan area have had a significant impact on the extreme temperatures occurring during extreme heat events. Simulations show that new urban development has caused an intensification and expansion of the areas experiencing extreme heat waves with an average increase in temperature of approximately 0.60°C. This change is most obvious at night with an increase up to 0.95°C, for which the total contribution of anthropogenic heat is 34%. We also simulate the effects of geo-engineering strategies increasing the albedo of urban roofs. White roofs reflect a large fraction of incoming sunlight in the daytime, which reduced the net radiation so that the roof surface keep at a lower temperature than regular solar-absorptive roofs. Urban net radiation decreases by approximately 200 W m-2 at local noon because of high solar reflectance of white roofs, which cools the daytime urban temperature afer sunrise, with the largest decrease of almost -0.80

  7. Overview of the biology of extreme events

    Science.gov (United States)

    Gutschick, V. P.; Bassirirad, H.

    2008-12-01

    Extreme events have, variously, meteorological origins as in heat waves or precipitation extremes, or biological origins as in pest and disease eruptions (or tectonic, earth-orbital, or impact-body origins). Despite growing recognition that these events are changing in frequency and intensity, a universal model of ecological responses to these events is slow to emerge. Extreme events, negative and positive, contrast with normal events in terms of their effects on the physiology, ecology, and evolution of organisms, hence also on water, carbon, and nutrient cycles. They structure biogeographic ranges and biomes, almost surely more than mean values often used to define biogeography. They are challenging to study for obvious reasons of field-readiness but also because they are defined by sequences of driving variables such as temperature, not point events. As sequences, their statistics (return times, for example) are challenging to develop, as also from the involvement of multiple environmental variables. These statistics are not captured well by climate models. They are expected to change with climate and land-use change but our predictive capacity is currently limited. A number of tools for description and analysis of extreme events are available, if not widely applied to date. Extremes for organisms are defined by their fitness effects on those organisms, and are specific to genotypes, making them major agents of natural selection. There is evidence that effects of extreme events may be concentrated in an extended recovery phase. We review selected events covering ranges of time and magnitude, from Snowball Earth to leaf functional loss in weather events. A number of events, such as the 2003 European heat wave, evidence effects on water and carbon cycles over large regions. Rising CO2 is the recent extreme of note, for its climatic effects and consequences for growing seasons, transpiration, etc., but also directly in its action as a substrate of photosynthesis

  8. Application of probabilistic event attribution in the summer heat extremes in the western US to emissions traced to major industrial carbon producers

    Science.gov (United States)

    Mera, R. J.; Allen, M. R.; Mote, P.; Ekwurzel, B.; Frumhoff, P. C.; Rupp, D. E.

    2015-12-01

    Heat waves in the western US have become progressively more severe due to increasing relative humidity and nighttime temperatures, increasing the health risks of vulnerable portions of the population, including Latino farmworkers in California's Central Valley and other socioeconomically disadvantaged communities. Recent research has shown greenhouse gas emissions doubled the risk of the hottest summer days during the 2000's in the Central Valley, increasing public health risks and costs, and raising the question of which parties are responsible for paying these costs. It has been argued that these costs should not be taken up solely by the general public through taxation, but that additional parties can be considered, including multinational corporations who have extracted and marketed a large proportion of carbon-based fuels. Here, we apply probabilistic event attribution (PEA) to assess the contribution of emissions traced to the world's 90 largest major industrial carbon producers to the severity and frequency of these extreme heat events. Our research uses very large ensembles of regional climate model simulations to calculate fractional attribution of policy-relevant extreme heat variables. We compare a full forcings world with observed greenhouse gases, sea surface temperatures and sea ice extent to a counter-factual world devoid of carbon pollution from major industrial carbon producers. The results show a discernable fraction of record-setting summer temperatures in the western US during the 2000's can be attributed to emissions sourced from major carbon producers.

  9. On causality of extreme events

    CERN Document Server

    Zanin, Massimiliano

    2016-01-01

    Multiple metrics have been developed to detect causality relations between data describing the elements constituting complex systems, all of them considering their evolution through time. Here we propose a metric able to detect causality within static data sets, by analysing how extreme events in one element correspond to the appearance of extreme events in a second one. The metric is able to detect both linear and non-linear causalities; to analyse both cross-sectional and longitudinal data sets; and to discriminate between real causalities and correlations caused by confounding factors. We validate the metric through synthetic data, dynamical and chaotic systems, and data representing the human brain activity in a cognitive task.

  10. On causality of extreme events

    Directory of Open Access Journals (Sweden)

    Massimiliano Zanin

    2016-06-01

    Full Text Available Multiple metrics have been developed to detect causality relations between data describing the elements constituting complex systems, all of them considering their evolution through time. Here we propose a metric able to detect causality within static data sets, by analysing how extreme events in one element correspond to the appearance of extreme events in a second one. The metric is able to detect non-linear causalities; to analyse both cross-sectional and longitudinal data sets; and to discriminate between real causalities and correlations caused by confounding factors. We validate the metric through synthetic data, dynamical and chaotic systems, and data representing the human brain activity in a cognitive task. We further show how the proposed metric is able to outperform classical causality metrics, provided non-linear relationships are present and large enough data sets are available.

  11. On causality of extreme events

    Science.gov (United States)

    2016-01-01

    Multiple metrics have been developed to detect causality relations between data describing the elements constituting complex systems, all of them considering their evolution through time. Here we propose a metric able to detect causality within static data sets, by analysing how extreme events in one element correspond to the appearance of extreme events in a second one. The metric is able to detect non-linear causalities; to analyse both cross-sectional and longitudinal data sets; and to discriminate between real causalities and correlations caused by confounding factors. We validate the metric through synthetic data, dynamical and chaotic systems, and data representing the human brain activity in a cognitive task. We further show how the proposed metric is able to outperform classical causality metrics, provided non-linear relationships are present and large enough data sets are available. PMID:27330866

  12. 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...

  13. Interpretation of Extreme Scattering Events

    CERN Document Server

    Walker, M A

    2000-01-01

    Extreme Scattering Events are sometimes manifest in the light-curves of compact radio-quasars at frequencies of a few GHz. These events are not understood. The model which appears to offer the best explanation requires a new population of AU-sized, neutral gas clouds; these clouds would then make up a large fraction of the Galaxy's dark matter. Independent of the question of which theoretical model is correct, if we extrapolate the observed behaviour to low radio-frequencies, we expect that the sky should be criss-crossed by a network of narrow caustics, at frequencies below about 700 MHz. Consequently at these frequencies sources should typically manifest additional, faint images which are substantially delayed with respect to the primary image. Although some examples of this type of behaviour are already known, it is expected that these are just the tip of the iceberg, with strong selection biases having been imposed by the instrumentation employed to date.

  14. Chicago, IL Adapts to Improve Extreme Heat Preparedness

    Science.gov (United States)

    Recognizing that heat waves are expected to increase in Chicago due to climate change,–supported by the Chicago Climate Impacts Report, the city adopted a comprehensive set of actions to reduce deaths from extreme heat events.

  15. 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.

  16. Extreme Events in Nature and Society

    CERN Document Server

    Albeverio, Sergio; Kantz, Holger

    2006-01-01

    Significant, and usually unwelcome, surprises, such as floods, financial crisis, epileptic seizures, or material rupture, are the topics of Extreme Events in Nature and Society. The book, authored by foremost experts in these fields, reveals unifying and distinguishing features of extreme events, including problems of understanding and modelling their origin, spatial and temporal extension, and potential impact. The chapters converge towards the difficult problem of anticipation: forecasting the event and proposing measures to moderate or prevent it. Extreme Events in Nature and Society will interest not only specialists, but also the general reader eager to learn how the multifaceted field of extreme events can be viewed as a coherent whole.

  17. Extreme weather events and infectious disease outbreaks

    OpenAIRE

    McMichael, Anthony J.

    2015-01-01

    Human-driven climatic changes will fundamentally influence patterns of human health, including infectious disease clusters and epidemics following extreme weather events. Extreme weather events are projected to increase further with the advance of human-driven climate change. Both recent and historical experiences indicate that infectious disease outbreaks very often follow extreme weather events, as microbes, vectors and reservoir animal hosts exploit the disrupted social and environmental c...

  18. Extreme weather events and infectious disease outbreaks.

    Science.gov (United States)

    McMichael, Anthony J

    2015-01-01

    Human-driven climatic changes will fundamentally influence patterns of human health, including infectious disease clusters and epidemics following extreme weather events. Extreme weather events are projected to increase further with the advance of human-driven climate change. Both recent and historical experiences indicate that infectious disease outbreaks very often follow extreme weather events, as microbes, vectors and reservoir animal hosts exploit the disrupted social and environmental conditions of extreme weather events. This review article examines infectious disease risks associated with extreme weather events; it draws on recent experiences including Hurricane Katrina in 2005 and the 2010 Pakistan mega-floods, and historical examples from previous centuries of epidemics and 'pestilence' associated with extreme weather disasters and climatic changes. A fuller understanding of climatic change, the precursors and triggers of extreme weather events and health consequences is needed in order to anticipate and respond to the infectious disease risks associated with human-driven climate change. Post-event risks to human health can be constrained, nonetheless, by reducing background rates of persistent infection, preparatory action such as coordinated disease surveillance and vaccination coverage, and strengthened disaster response. In the face of changing climate and weather conditions, it is critically important to think in ecological terms about the determinants of health, disease and death in human populations.

  19. Characterizing extreme and oppressive heat waves in Illinois

    Science.gov (United States)

    Ford, Trent W.; Schoof, Justin T.

    2017-01-01

    Heat waves are characteristic features of summertime climate in the Midwest United States and can have significant agricultural, hydrological, and societal impacts. Historically, heat waves in the Midwest state of Illinois have been either extreme (high temperature and low humidity) or oppressive (high temperature and high humidity) in nature, but our knowledge of the factors determining which heat wave type occurs is limited. We use self-organizing maps to classify synoptic-scale atmospheric circulation patterns associated with oppressive and extreme heat events and analysis of variance to evaluate the atmospheric and land surface features responsible for differences in humidity that characterize the two. We find that the majority of extreme and oppressive heat events are associated with similar synoptic-scale atmospheric conditions. Additionally, both locally evaporated moisture and advected moisture sources were important for determining which of the two heat wave types occurred. Specifically, oppressive heat waves were characterized by abundant antecedent precipitation, surplus soil moisture, and elevated evapotranspiration and related atmospheric humidity. Lower humidity levels during extreme heat wave events were driven by relative reductions in evapotranspiration due to limited soil water content. Overall, our results suggest that the onset of heat waves in Illinois is primarily driven by circulation features in the upper atmosphere; however, the distinction of extreme or oppressive heat wave is due to differences in boundary layer humidity, driven in part by land surface moisture availability for evapotranspiration.

  20. Characteristics of Extreme Auroral Charging Events

    Science.gov (United States)

    Minow, Joseph I.; Willis, Emily; Parker, Linda Neergaard

    2014-01-01

    Today’s presentation describes preliminary results from a study of extreme auroral charging in low Earth orbit. Goal of study is to document characteristics of auroral charging events of importance to spacecraft design, operations, and anomaly investigations.

  1. Extreme events monitoring from space

    Science.gov (United States)

    Kerr, Yann; Bitar, Ahmad Al; Mahmoodi, Ali; Richaume, Philippe; Al-Yaari, Amen; Wigneron, Jean-Pierre

    2016-04-01

    The SMOS (Soil Moisture and Ocean Salinity) satellite was successfully launched in November 2009. This ESA led mission for Earth Observation is dedicated to provide soil moisture over continental surface (with an accuracy goal of 0.04 m3/m3), vegetation water content over land, and ocean salinity. These geophysical features are important as they control the energy balance between the surface and the atmosphere. Their knowledge at a global scale is of interest for climatic and weather researches, and in particular in improving model forecasts. The Soil Moisture and Ocean Salinity mission has now been collecting data for 6 years. The whole data set has just been reprocessed (Version 620 for levels 1 and 2 and version 3 for level 3 CATDS). After 6 years it seems important to start using data for having a look at anomalies and see how they can relate to large scale events The purpose of this communication is to present the mission results after more than six years in orbit in a climatic trend perspective, as through such a period anomalies can be detected. Thereby we benefit from consistent datasets provided through the latest reprocessing using most recent algorithm enhancements. Using the above mentioned products it is possible to follow large events such as the evolution of the droughts in North America, or water fraction evolution over the Amazonian basin. In this occasion we will focus on the analysis of SMOS and ancillary products anomalies to reveal two climatic trends, the temporal evolution of water storage over the Indian continent in relation to rainfall anomalies, and the global impact of El Nino types of events on the general water storage distribution. This presentation shows in detail the use of long term data sets of L-band microwave radiometry in two specific cases, namely droughts and water budget over a large basin. Several other analyses are under way currently. Obviously, vegetation water content, but also dielectric constant, are carrying a wealth

  2. SMOS data and extreme events

    Science.gov (United States)

    Kerr, Yann; Wigneron, Jean-Pierre; Ferrazzoli, Paolo; Mahmoodi, Ali; Al-Yaari, Amen; Parrens, Marie; Bitar, Ahmad Al; Rodriguez-Fernandez, Nemesio; Bircher, Simone; Molero-rodenas, Beatriz; Drusch, Matthias; Mecklenburg, Susanne

    2017-04-01

    The SMOS (Soil Moisture and Ocean Salinity) satellite was successfully launched in November 2009. This ESA led mission for Earth Observation is dedicated to provide soil moisture over continental surface (with an accuracy goal of 0.04 m3/m3), vegetation water content over land, and ocean salinity. These geophysical features are important as they control the energy balance between the surface and the atmosphere. Their knowledge at a global scale is of interest for climatic and weather researches, and in particular in improving model forecasts. The Soil Moisture and Ocean Salinity mission has now been collecting data for over 7 years. The whole data set has been reprocessed (Version 620 for levels 1 and 2 and version 3 for level 3 CATDS) while operational near real time soil moisture data is now available and assimilation of SMOS data in NWP has proved successful. After 7 years it seems important to start using data for having a look at anomalies and see how they can relate to large scale events. We have also produced a 15 year soil moisture data set by merging SMOS and AMSR using a neural network approach. The purpose of this communication is to present the mission results after more than seven years in orbit in a climatic trend perspective, as through such a period anomalies can be detected. Thereby we benefit from consistent datasets provided through the latest reprocessing using most recent algorithm enhancements. Using the above mentioned products it is possible to follow large events such as the evolution of the droughts in North America, or water fraction evolution over the Amazonian basin. In this occasion we will focus on the analysis of SMOS and ancillary products anomalies to reveal two climatic trends, the temporal evolution of water storage over the Indian continent in relation to rainfall anomalies, and the global impact of El Nino types of events on the general water storage distribution. This presentation shows in detail the use of long term data sets

  3. Extreme Heat in Southwest a Deadly Threat

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_166797.html Extreme Heat in Southwest a Deadly Threat Here's how to ... t take off in Phoenix on Tuesday, the heat wave scorching the Southwest for the next week ...

  4. 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

  5. Predictability of extreme events in social media

    CERN Document Server

    Miotto, José M

    2014-01-01

    It is part of our daily social-media experience that seemingly ordinary items (videos, news, publications, etc.) unexpectedly gain an enormous amount of attention. Here we investigate how unexpected these events are. We propose a method that, given some information on the items, quantifies the predictability of events, i.e., the potential of identifying in advance the most successful items defined as the upper bound for the quality of any prediction based on the same information. Applying this method to different data, ranging from views in YouTube videos to posts in Usenet discussion groups, we invariantly find that the predictability increases for the most extreme events. This indicates that, despite the inherently stochastic collective dynamics of users, efficient prediction is possible for the most extreme events.

  6. A Fourier analysis of extreme events

    DEFF Research Database (Denmark)

    Mikosch, Thomas Valentin; Zhao, Yuwei

    2014-01-01

    The extremogram is an asymptotic correlogram for extreme events constructed from a regularly varying stationary sequence. In this paper, we define a frequency domain analog of the correlogram: a periodogram generated from a suitable sequence of indicator functions of rare events. We derive basic ...... properties of the periodogram such as the asymptotic independence at the Fourier frequencies and use this property to show that weighted versions of the periodogram are consistent estimators of a spectral density derived from the extremogram....

  7. On Extreme Events in Banking and Finance

    NARCIS (Netherlands)

    M.R.C. Oordt (Maarten)

    2013-01-01

    textabstractUncertainty and new developments spread at an astonishing speed across the globe in financial markets. The recent extreme events in banking and finance triggered many new questions among academics, policy makers and the general public. Is global diversification at financial institutions

  8. Irrigation mitigates against heat extremes

    Science.gov (United States)

    Thiery, Wim; Fischer, Erich; Visser, Auke; Hirsch, Annette L.; Davin, Edouard L.; Lawrence, Dave; Hauser, Mathias; Seneviratne, Sonia I.

    2017-04-01

    Irrigation is an essential practice for sustaining global food production and many regional economies. Emerging scientific evidence indicates that irrigation substantially affects mean climate conditions in different regions of the world. Yet how this practice influences climate extremes is currently unknown. Here we use gridded observations and ensemble simulations with the Community Earth System Model to assess the impacts of irrigation on climate extremes. While the influence of irrigation on annual mean temperatures is limited, we find a large impact on temperature extremes, with a particularly strong cooling during the hottest day of the year (-0.78 K averaged over irrigated land). The strong influence on hot extremes stems from the timing of irrigation and its influence on land-atmosphere coupling strength. Together these effects result in asymmetric temperature responses, with a more pronounced cooling during hot and/or dry periods. The influence of irrigation is even more pronounced when considering subgrid-scale model output, suggesting that local effects of land management are far more important than previously thought. Finally we find that present-day irrigation is partly masking GHG-induced warming of extreme temperatures, with particularly strong effects in South Asia. Our results overall underline that irrigation substantially reduces our exposure to hot temperature extremes and highlight the need to account for irrigation in future climate projections.

  9. The National Extreme Events Data and Research Center (NEED)

    Science.gov (United States)

    Gulledge, J.; Kaiser, D. P.; Wilbanks, T. J.; Boden, T.; Devarakonda, R.

    2014-12-01

    The Climate Change Science Institute at Oak Ridge National Laboratory (ORNL) is establishing the National Extreme Events Data and Research Center (NEED), with the goal of transforming how the United States studies and prepares for extreme weather events in the context of a changing climate. NEED will encourage the myriad, distributed extreme events research communities to move toward the adoption of common practices and will develop a new database compiling global historical data on weather- and climate-related extreme events (e.g., heat waves, droughts, hurricanes, etc.) and related information about impacts, costs, recovery, and available research. Currently, extreme event information is not easy to access and is largely incompatible and inconsistent across web sites. NEED's database development will take into account differences in time frames, spatial scales, treatments of uncertainty, and other parameters and variables, and leverage informatics tools developed at ORNL (i.e., the Metadata Editor [1] and Mercury [2]) to generate standardized, robust documentation for each database along with a web-searchable catalog. In addition, NEED will facilitate convergence on commonly accepted definitions and standards for extreme events data and will enable integrated analyses of coupled threats, such as hurricanes/sea-level rise/flooding and droughts/wildfires. Our goal and vision is that NEED will become the premiere integrated resource for the general study of extreme events. References: [1] Devarakonda, Ranjeet, et al. "OME: Tool for generating and managing metadata to handle BigData." Big Data (Big Data), 2014 IEEE International Conference on. IEEE, 2014. [2] Devarakonda, Ranjeet, et al. "Mercury: reusable metadata management, data discovery and access system." Earth Science Informatics 3.1-2 (2010): 87-94.

  10. 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 ...

  11. Biological Extreme Events - Past, Present, and Future

    Science.gov (United States)

    Gutschick, V. P.

    2010-12-01

    Biological extreme events span wide ranges temporally and spatially and in type - population dieoffs, extinctions, ecological reorganizations, changes in biogeochemical fluxes, and more. Driving variables consist in meteorology, tectonics, orbital changes, anthropogenic changes (land-use change, species introductions, reactive N injection into the biosphere), and evolution (esp. of diseases). However, the mapping of extremes in the drivers onto biological extremes as organismal responses is complex, as laid out originally in the theoretical framework of Gutschick and BassiriRad (New Phytologist [2003] 100:21-42). Responses are nonlinear and dependent on (mostly unknown and) complex temporal sequences - often of multiple environmental variables. The responses are species- and genotype specific. I review extreme events over from past to present over wide temporal scales, while noting that they are not wholly informative of responses to the current and near-future drivers for at least two reasons: 1) the current combination of numerous environmental extremes - changes in CO2, temperature, precipitation, reactive N, land fragmentation, O3, etc. -is unprecedented in scope, and 2) adaptive genetic variation for organismal responses is constrained by poorly-characterized genetic structures (in organisms and populations) and by loss of genetic variation by genetic drift over long periods. We may expect radical reorganizations of ecosystem and biogeochemical functions. These changes include many ecosystem services in flood control, crop pollination and insect/disease control, C-water-mineral cycling, and more, as well as direct effects on human health. Predictions of such changes will necessarily be very weak in the critical next few decades, given the great deal of observation, experimentation, and theory construction that will be necessary, on both organisms and drivers. To make the research efforts most effective will require extensive, insightful planning, beginning

  12. Extreme cyclone events in the Arctic: Wintertime variability and trends

    Science.gov (United States)

    Rinke, A.; Maturilli, M.; Graham, R. M.; Matthes, H.; Handorf, D.; Cohen, L.; Hudson, S. R.; Moore, J. C.

    2017-09-01

    Typically 20-40 extreme cyclone events (sometimes called ‘weather bombs’) occur in the Arctic North Atlantic per winter season, with an increasing trend of 6 events/decade over 1979-2015, according to 6 hourly station data from Ny-Ålesund. This increased frequency of extreme cyclones is consistent with observed significant winter warming, indicating that the meridional heat and moisture transport they bring is a factor in rising temperatures in the region. The winter trend in extreme cyclones is dominated by a positive monthly trend of about 3-4 events/decade in November-December, due mainly to an increasing persistence of extreme cyclone events. A negative trend in January opposes this, while there is no significant trend in February. We relate the regional patterns of the trend in extreme cyclones to anomalously low sea-ice conditions in recent years, together with associated large-scale atmospheric circulation changes such as ‘blockinglike’ circulation patterns (e.g. Scandinavian blocking in December and Ural blocking during January-February).

  13. Frequently Asked Questions (FAQ) about Extreme Heat

    Science.gov (United States)

    ... Part 3 of 3) Hot Weather Tips Heat Stress in Older Adults FAQs Extreme Heat PSAs Related Links MMWR Bibliography CDC's Program Floods Flood Readiness Personal Hygiene After a Disaster Cleanup of Flood Water After a Flood Worker Safety Educational Materials Floods ...

  14. Are extreme events (statistically) special? (Invited)

    Science.gov (United States)

    Main, I. G.; Naylor, M.; Greenhough, J.; Touati, S.; Bell, A. F.; McCloskey, J.

    2009-12-01

    We address the generic problem of testing for scale-invariance in extreme events, i.e. are the biggest events in a population simply a scaled model of those of smaller size, or are they in some way different? Are large earthquakes for example ‘characteristic’, do they ‘know’ how big they will be before the event nucleates, or is the size of the event determined only in the avalanche-like process of rupture? In either case what are the implications for estimates of time-dependent seismic hazard? One way of testing for departures from scale invariance is to examine the frequency-size statistics, commonly used as a bench mark in a number of applications in Earth and Environmental sciences. Using frequency data however introduces a number of problems in data analysis. The inevitably small number of data points for extreme events and more generally the non-Gaussian statistical properties strongly affect the validity of prior assumptions about the nature of uncertainties in the data. The simple use of traditional least squares (still common in the literature) introduces an inherent bias to the best fit result. We show first that the sampled frequency in finite real and synthetic data sets (the latter based on the Epidemic-Type Aftershock Sequence model) converge to a central limit only very slowly due to temporal correlations in the data. A specific correction for temporal correlations enables an estimate of convergence properties to be mapped non-linearly on to a Gaussian one. Uncertainties closely follow a Poisson distribution of errors across the whole range of seismic moment for typical catalogue sizes. In this sense the confidence limits are scale-invariant. A systematic sample bias effect due to counting whole numbers in a finite catalogue makes a ‘characteristic’-looking type extreme event distribution a likely outcome of an underlying scale-invariant probability distribution. This highlights the tendency of ‘eyeball’ fits to unconsciously (but

  15. Energy Infrastructure and Extreme Events (Invited)

    Science.gov (United States)

    Wakimoto, R. M.

    2013-12-01

    The country's energy infrastructure is sensitive to the environment, especially extreme events. Increasing global temperatures, intense storms, and space weather have the potential to disrupt energy production and transport. It can also provide new opportunities as illustrated by the opening of the Northwest Passage. The following provides an overview of some of the high impacts of major geophysical events on energy production and transport. Future predictions of hurricanes suggest that we can expect fewer storms but they will be associated with stronger winds and more precipitation. The winds and storm surge accompanying hurricane landfall along the Gulf States has had a major impact on the coastal energy infrastructure and the oil/natural gas platforms. The impact of these surges will increase with predicted sea level rise. Hurricane Katrina caused damage to crude oil pipelines and refineries that reduced oil production by 19% for the year. The disruption that can occur is not necessarily linked with the maximum winds of the tropical storm as recently shown by Hurricane Sandy which was classified as a ';post-tropical cyclone' during landfall. Another intense circulation, the tornado, can also cause power outages and network breaks from high winds that can topple power poles or damage power lines from fallen trees. Fortunately, the Moore tornado, rated EF5, did not have a major impact on the oil and gas infrastructure in Oklahoma. The impact of earthquakes and tsunamis on energy was illustrated in Japan in 2011 with the shutdown of the Fukushima Daiichi plant. Other studies have suggested that there are areas in the United States where the energy services are highly vulnerable to major earthquakes that would disrupt electrical and gas networks for extended periods of time. Seismic upgrades to the energy infrastructure would help mitigate the impact. In 1859, a coronal mass ejection triggered a geomagnetic storm that disrupted communication wires around the world

  16. Impacts of Diabatic Heating Anomalies on an Extreme Snow Event over South China in January 2008%热源异常对2008年初中国南方低温雨雪天气的影响

    Institute of Scientific and Technical Information of China (English)

    李来芳; 刘屹岷; 卜昌郁

    2011-01-01

    利用资料诊断和全球大气原始方程模式(Intermediate General Circulation Model,IGCM),研究了2008年1月中国南方地区出现罕见的持续性雨雪事件的成因.结果表明,2008年1月大气非绝热加热场的主要异常出现在热带海洋、青藏高原及中亚地区以及北大西洋.用全球异常热源强迫IGCM得到的对流层中低层环流场异常和再分析资料结果十分接近,说明非绝热加热异常和该事件密切相关.分区试验的结果显示青藏高原以及中亚地区的加热异常是导致此次事件的主要原因,中高纬度北大西洋上的海温异常也有一定贡献.前者在中国南方产生了中低层的异常南风气流和贡献率约为95%的异常垂直上升运动,加强了向中国南方的水汽输送;后者加强了北大西洋涛动正位相,能导致12%的垂直运动异常和相对于观测偏弱的环流异常.另一方面,虽然赤道中部太平洋La Nina事件对应的热汇有利于此次事件的发生,但是热带太平洋La Nina型海温分布的综合效应对此次事件的贡献为负,贡献率约为一27%.%An extreme event, an unusual snowstorm happening in South China in January 2008, is studied with observational data analysis and numerical modeling experiments. It is found that diabatic heating was centered in the tropical oceans, Central Asia, the Tibetan Plateau, and the North Atlantic Ocean. The results from the numerical experiments demonstrate that global diabatic heating anomalies are responsible for this extreme event. A series of numerical experiments are further designed to identify the key areas where the diabatic heating anomalies occur. The results indicate that the diabatic heating anomalies in Central Asia and the Tibetan Plateau could account for the extreme heavy snow event. Such anomalies generate anomalous air mass rising as well as southerly winds over South China. These features facilitate the water vapor transportation and result in the heavy

  17. 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

  18. Bubble heating in Extreme Cooling Clusters

    Science.gov (United States)

    Allen, Steven

    2007-09-01

    Our proposal targets `extreme cooling' clusters: those systems with the largest, fastest cooling rates that most severely challenge the AGN-heating paradigm for cluster cores. By targeting two X-ray bright `extreme cooling cluters' with the clearest radio bubbles in their cores, we seek to establish whether it is possible for AGN heating to balance cooling in such systems. If cooling is not balanced by some heat source, then large residual cooling rates should be detectable in the spectral X-ray data. We will measure the bubble properties precisely and map the spatial-spectral structure of the surrounding X-ray gas, searching for ghost bubbles, shocks, ripples, fronts and non-thermal emission.

  19. Extreme Events and Energy Providers: Science and Innovation

    Science.gov (United States)

    Yiou, P.; Vautard, R.

    2012-04-01

    Most socio-economic regulations related to the resilience to climate extremes, from infrastructure or network design to insurance premiums, are based on a present-day climate with an assumption of stationarity. Climate extremes (heat waves, cold spells, droughts, storms and wind stilling) affect in particular energy production, supply, demand and security in several ways. While national, European or international projects have generated vast amounts of climate projections for the 21st century, their practical use in long-term planning remains limited. Estimating probabilistic diagnostics of energy user relevant variables from those multi-model projections will help the energy sector to elaborate medium to long-term plans, and will allow the assessment of climate risks associated to those plans. The project "Extreme Events for Energy Providers" (E3P) aims at filling a gap between climate science and its practical use in the energy sector and creating in turn favourable conditions for new business opportunities. The value chain ranges from addressing research questions directly related to energy-significant climate extremes to providing innovative tools of information and decision making (including methodologies, best practices and software) and climate science training for the energy sector, with a focus on extreme events. Those tools will integrate the scientific knowledge that is developed by scientific communities, and translate it into a usable probabilistic framework. The project will deliver projection tools assessing the probabilities of future energy-relevant climate extremes at a range of spatial scales varying from pan-European to local scales. The E3P project is funded by the Knowledge and Innovation Community (KIC Climate). We will present the mechanisms of interactions between academic partners, SMEs and industrial partners for this project. Those mechanisms are elementary bricks of a climate service.

  20. Possible future changes in extreme events over Northern Eurasia

    Science.gov (United States)

    Monier, Erwan; Sokolov, Andrei; Scott, Jeffery

    2013-04-01

    In this study, we investigate possible future climate change over Northern Eurasia and its impact on extreme events. Northern Eurasia is a major player in the global carbon budget because of boreal forests and peatlands. Circumpolar boreal forests alone contain more than five times the amount of carbon of temperate forests and almost double the amount of carbon of the world's tropical forests. Furthermore, severe permafrost degradation associated with climate change could result in peatlands releasing large amounts of carbon dioxide and methane. Meanwhile, changes in the frequency and magnitude of extreme events, such as extreme precipitation, heat waves or frost days are likely to have substantial impacts on Northern Eurasia ecosystems. For this reason, it is very important to quantify the possible climate change over Northern Eurasia under different emissions scenarios, while accounting for the uncertainty in the climate response and changes in extreme events. For several decades, the Massachusetts Institute of Technology (MIT) Joint Program on the Science and Policy of Global Change has been investigating uncertainty in climate change using the MIT Integrated Global System Model (IGSM) framework, an integrated assessment model that couples an earth system model of intermediate complexity (with a 2D zonal-mean atmosphere) to a human activity model. In this study, regional change is investigated using the MIT IGSM-CAM framework that links the IGSM to the National Center for Atmospheric Research (NCAR) Community Atmosphere Model (CAM). New modules were developed and implemented in CAM to allow climate parameters to be changed to match those of the IGSM. The simulations presented in this paper were carried out for two emission scenarios, a "business as usual" scenario and a 660 ppm of CO2-equivalent stabilization, which are similar to, respectively, the Representative Concentration Pathways RCP8.5 and RCP4.5 scenarios. Values of climate sensitivity and net aerosol

  1. Uncertainty analysis in statistical modeling of extreme hydrological events

    NARCIS (Netherlands)

    Xu, Yue-Ping; Booij, Martijn J.; Tong, Yang-Bin

    2010-01-01

    With the increase of both magnitude and frequency of hydrological extreme events such as drought and flooding, the significance of adequately modeling hydrological extreme events is fully recognized. Estimation of extreme rainfall/flood for various return periods is of prime importance for hydrologi

  2. Pulsar Observations of Extreme Scattering Events

    CERN Document Server

    Coles, W A; Shannon, R M; Hobbs, G; Manchester, R N; You, X P; Bailes, M; Bhat, N D R; Burke-Spolaor, S; Dai, S; Keith, M J; Levin, Y; Oslowski, S; Ravi, V; Reardon, D; Toomey, L; van Straten, W; Wang, J B; Wen, L; Zhu, X J

    2015-01-01

    Extreme scattering events (ESEs) in the interstellar medium (ISM) were first observed in regular flux measurements of compact extragalactic sources. They are characterized by a flux variation over a period of weeks, suggesting the passage of a "diverging plasma lens" across the line of sight. Modeling the refraction of such a lens indicates that the structure size must be of order AU and the electron density of order 10s of cm^{-3}. Similar structures have been observed in measurements of pulsar intensity scintillation and group delay. Here we report observations of two ESEs showing increases in both intensity scintillation and dispersion made with the Parkes Pulsar Timing Array (PPTA). These allow us to make more complete models of the ESE, including an estimate of the "outer-scale" of the turbulence in the plasma lens. These observations show clearly that the ESE structure is fully turbulent on an AU scale. They provide some support for the idea that the structures are extended along the line of sight, such...

  3. [Sports and extreme conditions. Cardiovascular incidence in long term exertion and extreme temperatures (heat, cold)].

    Science.gov (United States)

    Melin, B; Savourey, G

    2001-06-30

    During ultra-endurance exercise, both increase in body temperature and dehydration due to sweat losses, lead to a decrease in central blood volume. The heart rate drift allows maintaining appropriate cardiac output, in order to satisfy both muscle perfusion and heat transfer requirements by increasing skin blood flow. The resulting dehydration can impair thermal regulation and increase the risks of serious accidents as heat stroke. Endurance events, lasting more than 8 hours, result in large sweat sodium chloride losses. Thus, ingestion of large amounts of water with poor salt intake can induce symptomatic hyponatremia (plasma sodium extreme condition.

  4. Extreme sport participation as serious leisure : athletes' overall satisfaction with the event extreme sports week

    OpenAIRE

    Rumba, Maira

    2012-01-01

    This study is concentrating on the extreme sport athletes who have participated in the spectacular event Extreme Sport Week (Mykletun, 2009; Ekstremsportveko, 2012) in Voss, Norway 2011. In particular, it addresses the extreme sport athletes’ involvement with the sport, their career development, and their experiences during the event. The aim is to investigate extreme sport athletes satisfaction with the event based on Pine and Gilmore’s (1999) experience four-realm model and Getz’s and Ander...

  5. Spatiotemporal Chaos Induces Extreme Events in an Extended Microcavity Laser

    Science.gov (United States)

    Selmi, F.; Coulibaly, S.; Loghmari, Z.; Sagnes, I.; Beaudoin, G.; Clerc, M. G.; Barbay, S.

    2016-01-01

    Extreme events such as rogue waves in optics and fluids are often associated with the merging dynamics of coherent structures. We present experimental and numerical results on the physics of extreme event appearance in a spatially extended semiconductor microcavity laser with an intracavity saturable absorber. This system can display deterministic irregular dynamics only, thanks to spatial coupling through diffraction of light. We have identified parameter regions where extreme events are encountered and established the origin of this dynamics in the emergence of deterministic spatiotemporal chaos, through the correspondence between the proportion of extreme events and the dimension of the strange attractor.

  6. 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.

  7. A Fourier analysis of extremal events

    DEFF Research Database (Denmark)

    Zhao, Yuwei

    is the extremal periodogram. The extremal periodogram shares numerous asymptotic properties with the periodogram of a linear process in classical time series analysis: the asymptotic distribution of the periodogram ordinates at the Fourier frequencies have a similar form and smoothed versions of the periodogram...

  8. Extreme seawater compositions during Oceanic Anoxic Events

    Science.gov (United States)

    Cohen, A.; Bottini, C.; Dickson, A. J.; Izon, G. J.; Coe, A. L.

    2012-12-01

    For almost the entire duration of the Phanerozoic, the oceans have remained well oxygenated and highly conducive to the development of animal and plant life. However, there have been relatively brief intervals, known as Oceanic Anoxic Events (OAEs), when a very significant expansion of low-oxygen regions occurred throughout the world's oceans. OAEs were characterised by highly atypical seawater chemistry, as reflected in the chemical and isotopic compositions of contemporaneous sediments and fossil remains. These oxygen-deficient intervals also exerted profound pressures on many marine species as indicated by major changes in species populations and distributions. High-resolution chemical and isotopic data recovered from marine sediments and sedimentary rocks, together with biotic information, provide us with the best means of understanding the significance of OAEs and their place in the evolution of the Earth system. We present new Mo- and Os-isotope and geochemical data from OAE 1a (early Cretaceous), which help define how this event evolved in relation to the other major environmental parameters - including global warming, continental weathering and Ontong-Java volcanism - of that time. We compare these new observations with published results from other Mesozoic OAEs and the PETM. Recently published Os-isotope data from DSDP site 463 (mid-Pacific) [1] and northern Italy [1, 2] show that the Os budget of the oceans was dominated for a period of c. 880 ka during OAE 1a by the hydrothermal flux of unradiogenic Os from the Ontong-Java province. The observation of identical Os-isotope compositions at these two very distant sites indicates that seawater was well mixed at that time. Over the same interval, the seawater Mo-isotope composition, based upon well-preserved samples from Italy, was persistently atypical, with δ98/95Mo ranging between -0.7 and +0.7 permil [3]. All the samples analysed here accumulated under highly anoxic conditions and contain highly abundant

  9. 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

  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

  11. 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.

  12. Extreme heat and runoff extremes in the Swiss Alps

    Directory of Open Access Journals (Sweden)

    M. Zappa

    2007-06-01

    Full Text Available The hydrological response of Swiss river basins to the 2003 European summer heatwave was evaluated by a combined analysis of historical discharge records and specific applications of distributed hydrological modeling. In the summer of 2003, the discharge from headwater streams of the Swiss Central Plateau was only 40%–60% of the long-term average. For alpine basins runoff was about 60%–80% of the average. Glacierized basins showed the opposite behavior. According to the degree of glacierization, the average summer runoff was close or even above average. The hydrological model PREVAH was applied for the period 1982–2005. Even if the model was not calibrated for such extreme meteorological conditions, it was well able to simulate the hydrological responses of three basins. The aridity index φ describes feedbacks between hydrological and meteorological anomalies, and was adopted as an indicator of hydrological drought. The anomalies of φ and temperature in the summer of 2003 exceeded the 1982–2005 mean by more than 2 standard deviations. Catchments without glaciers showed negative correlations between φ and discharge R. In basins with about 15% glacierization, φ and R were not correlated. River basins with higher glacier percentages showed a positive correlation between φ and R. Icemelt was positively correlated with φ and reduced the variability of discharge with larger amounts of meltwater. Runoff generation from the non-glaciated sub-areas was limited by high evapotranspiration and reduced precipitation. The 2003 summer heatwave could be a precursor to similar events in the near future. Hydrological models and further data analysis will allow the identification of the most sensitive regions where heatwaves may become a recurrent natural hazard with large environmental, social and economical impacts.

  13. 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.

  14. Extreme events in multilayer, interdependent complex networks and control

    Science.gov (United States)

    Chen, Yu-Zhong; Huang, Zi-Gang; Zhang, Hai-Feng; Eisenberg, Daniel; Seager, Thomas P.; Lai, Ying-Cheng

    2015-11-01

    We investigate the emergence of extreme events in interdependent networks. We introduce an inter-layer traffic resource competing mechanism to account for the limited capacity associated with distinct network layers. A striking finding is that, when the number of network layers and/or the overlap among the layers are increased, extreme events can emerge in a cascading manner on a global scale. Asymptotically, there are two stable absorption states: a state free of extreme events and a state of full of extreme events, and the transition between them is abrupt. Our results indicate that internal interactions in the multiplex system can yield qualitatively distinct phenomena associated with extreme events that do not occur for independent network layers. An implication is that, e.g., public resource competitions among different service providers can lead to a higher resource requirement than naively expected. We derive an analytical theory to understand the emergence of global-scale extreme events based on the concept of effective betweenness. We also articulate a cost-effective control scheme through increasing the capacity of very few hubs to suppress the cascading process of extreme events so as to protect the entire multi-layer infrastructure against global-scale breakdown.

  15. Extreme events in excitable systems and mechanisms of their generation.

    Science.gov (United States)

    Ansmann, Gerrit; Karnatak, Rajat; Lehnertz, Klaus; Feudel, Ulrike

    2013-11-01

    We study deterministic systems, composed of excitable units of FitzHugh-Nagumo type, that are capable of self-generating and self-terminating strong deviations from their regular dynamics without the influence of noise or parameter change. These deviations are rare, short-lasting, and recurrent and can therefore be regarded as extreme events. Employing a range of methods we analyze dynamical properties of the systems, identifying features in the systems' dynamics that may qualify as precursors to extreme events. We investigate these features and elucidate mechanisms that may be responsible for the generation of the extreme events.

  16. General Resilience to Cope with Extreme Events

    Directory of Open Access Journals (Sweden)

    Brian Walker

    2012-11-01

    Full Text Available Resilience to specified kinds of disasters is an active area of research and practice. However, rare or unprecedented disturbances that are unusually intense or extensive require a more broad-spectrum type of resilience. General resilience is the capacity of social-ecological systems to adapt or transform in response to unfamiliar, unexpected and extreme shocks. Conditions that enable general resilience include diversity, modularity, openness, reserves, feedbacks, nestedness, monitoring, leadership, and trust. Processes for building general resilience are an emerging and crucially important area of research.

  17. THE IMPACT OF EXTREME RISK EVENTS ON THE ECONOMY

    Directory of Open Access Journals (Sweden)

    Ionela-Daniela GĂITAN

    2016-02-01

    Full Text Available In this paper I wanted to highlight the impact of extreme risk events on the economy. The issue that I will approach in this paper is one of great importance, taking into account that extreme risk events that occur are  different  and are becoming more frequent  and harder to  control.  The quickly  development  of  these eventsrequires the implementation of a suitable risk management system. The complexity of this issue involves different approaches that can be interrelated in: computer science, mathematics, risk management, crisis management, andmodeling and simulation of extreme risk events. Natural disasters are rare events, but when they occur are causing a huge damage and an adequate management is necessary to return to a state of normality in a short time. To achieve our goal, in the first part of the paper, we presented the problems that an extreme risk event causes in a country when they occur. In the last part of the paper I presented analytical, statistical and econometric methods used in analysis of the impact on the economy of extreme risk events. Natural  disasters,  which  are  extreme  risk  events,  rarely  produce,  but  when  they  occur  causing  hugedamage and an adequate management is necessary to return to a state of normality in a short time.

  18. Crop Diversiifcation in Coping with Extreme Weather Events in China

    Institute of Scientific and Technical Information of China (English)

    HUANG Ji-kun; JIANG Jing; WANG Jin-xia; HOU Ling-ling

    2014-01-01

    Apart from the long-term effects of climate change, the frequency and severity of extreme weather events have been increasing. Given the risks posed by climate change, particularly the changes in extreme weather events, the question of how to adapt to these changes and mitigate their negative impacts has received great attention from policy makers. The overall goals of this study are to examine whether farmers adapt to extreme weather events through crop diversiifcation and which factors inlfuence farmers’ decisions on crop diversiifcation against extreme weather events in China. To limit the scope of this study, we focus on drought and lfood events only. Based on a unique large-scale household survey in nine provinces, this study ifnds that farmers respond to extreme weather events by increasing crop diversiifcation. Their decision to diversify crops is significantly influenced by their experiences of extreme weather events in the previous year. Such results are understandable because farmers’ behaviors are normally based on their expectations. Moreover, household characteristics also affect farmers’ decisions on crop diversiifcation strategy, and their effects differ by farmers’ age and gender. This paper concludes with several policy implications.

  19. Extreme water-related weather events and waterborne disease.

    Science.gov (United States)

    Cann, K F; Thomas, D Rh; Salmon, R L; Wyn-Jones, A P; Kay, D

    2013-04-01

    Global climate change is expected to affect the frequency, intensity and duration of extreme water-related weather events such as excessive precipitation, floods, and drought. We conducted a systematic review to examine waterborne outbreaks following such events and explored their distribution between the different types of extreme water-related weather events. Four medical and meteorological databases (Medline, Embase, GeoRef, PubMed) and a global electronic reporting system (ProMED) were searched, from 1910 to 2010. Eighty-seven waterborne outbreaks involving extreme water-related weather events were identified and included, alongside 235 ProMED reports. Heavy rainfall and flooding were the most common events preceding outbreaks associated with extreme weather and were reported in 55·2% and 52·9% of accounts, respectively. The most common pathogens reported in these outbreaks were Vibrio spp. (21·6%) and Leptospira spp. (12·7%). Outbreaks following extreme water-related weather events were often the result of contamination of the drinking-water supply (53·7%). Differences in reporting of outbreaks were seen between the scientific literature and ProMED. Extreme water-related weather events represent a risk to public health in both developed and developing countries, but impact will be disproportionate and likely to compound existing health disparities.

  20. Sovereign Default Analysis through Extreme Events Identification

    Directory of Open Access Journals (Sweden)

    Vasile George MARICA

    2015-06-01

    Full Text Available This paper investigates contagion in international credit markets through the use of a novel jump detection technique proposed by Chan and Maheuin (2002. This econometrical methodology is preferred because it is non-linear by definition and not a subject to volatility bias. Also, the identified jumps in CDS premiums are considered as outliers positioned beyond any stochastic movement that can and is already modelled through well-known linear analysis. Though contagion is hard to define, we show that extreme discrete movements in default probabilities inferred from CDS premiums can lead to sound economic conclusions about the risk profile of sovereign nations in international bond markets. We find evidence of investor sentiment clustering for countries with unstable political regimes or that are engaged in armed conflict. Countries that have in their recent history faced currency or financial crises are less vulnerable to external unexpected shocks. First we present a brief history of sovereign defaults with an emphasis on their increased frequency and geographical reach, as financial markets become more and more integrated. We then pass to a literature review of the most important definitions for contagion, and discuss what quantitative methods are available to detect the presence of contagion. The paper continues with the details for the methodology of jump detection through non-linear modelling and its use in the field of contagion identification. In the last sections we present the estimation results for simultaneous jumps between emerging markets CDS and draw conclusions on the difference of behavior in times of extreme movement versus tranquil periods.

  1. Understanding Extreme Spanish Coastal Flood Events

    Science.gov (United States)

    Diez, J. Javier; Esteban, M. Dolores; Silvestre, J. Manuel

    2013-04-01

    The Santa Irene flood event, at the end of October 1982, is one of the most dramatically widely reported flood events in Spain. Its renown is mainly due to the collapse of the Tous dam, but its main message is to be the paradigm of the incidence of the maritime/littoral weather and its temporal sea level rise by storm surge accompanying rain process on the coastal plains inland floods. Looking at damages the presentation analyzes the adapted measures from the point of view of the aims of the FP7 SMARTeST Project related to the Flood Resilience improvement in urban areas through looking for Technologies, Systems and Tools an appropriate "road to de market". The event was due to the meteorological phenomenon known as "gota fría" (cold drop), a relatively frequent and intense rainy phenomenon affecting one or more basins on the Iberian Peninsula, particularly on the Spanish east to southeast inlands and coasts. There are some circumstances that can easily come together to unleash the cold drop there: cold and dry polar air masses coming onto the whole Iberian Peninsula and the north of Africa, high sea water temperatures, and low atmospheric pressure (cyclone) areas in the western Mediterranean basin; these circumstances are quite common during the autumn season there, and, as it happens, in other places around the world (East/Southeast Africa). Their occurrence, however shows a great space-temporal variability (in a similar way to hurricanes, on Caribbean and western North-Atlantic areas, or to typhoons do). As a matter of fact, all of these equivalent though different phenomena may have different magnitude each time. An overview of the very main events since 11th century in the East to Southeast areas in Spain is shown in the presentation, looking for relation with climatic conditions and Climate changes on one hand, and with geomorphologic and geotechnical conditions on the other It also describes the results of a detailed analysis and reflection about this cold

  2. 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

  3. Measuring the effects of extreme weather events on yields

    Directory of Open Access Journals (Sweden)

    J.P. Powell

    2016-06-01

    Full Text Available Extreme weather events are expected to increase worldwide, therefore, anticipating and calculating their effects on crop yields is important for topics ranging from food security to the economic viability of biomass products. Given the local nature of weather, particularly precipitation, effects are best measured at a local level. This paper analyzes weather events at the level of the farm for a specific crop, winter wheat. Once it has been established that extreme events are expected to continue occurring at historically high levels for farming locations throughout the Netherlands, the effects of those events on wheat yields are estimated while controlling for the other major input factors affecting yields. Econometric techniques are applied to an unbalanced panel data set of 334 farms for a period of up to 12 years. Analyzes show that the number of days with extreme high temperatures in Dutch wheat growing regions has significantly increased since the early 1900s, while the number of extreme low temperature events has fallen over that same period. The effects of weather events on wheat yields were found to be time specific in that the week in which an event occurred determined its effect on yields. High temperature events and precipitation events were found to significantly decrease yields.

  4. Extreme event statistics in a drifting Markov chain

    Science.gov (United States)

    Kindermann, Farina; Hohmann, Michael; Lausch, Tobias; Mayer, Daniel; Schmidt, Felix; Widera, Artur

    2017-07-01

    We analyze extreme event statistics of experimentally realized Markov chains with various drifts. Our Markov chains are individual trajectories of a single atom diffusing in a one-dimensional periodic potential. Based on more than 500 individual atomic traces we verify the applicability of the Sparre Andersen theorem to our system despite the presence of a drift. We present detailed analysis of four different rare-event statistics for our system: the distributions of extreme values, of record values, of extreme value occurrence in the chain, and of the number of records in the chain. We observe that, for our data, the shape of the extreme event distributions is dominated by the underlying exponential distance distribution extracted from the atomic traces. Furthermore, we find that even small drifts influence the statistics of extreme events and record values, which is supported by numerical simulations, and we identify cases in which the drift can be determined without information about the underlying random variable distributions. Our results facilitate the use of extreme event statistics as a signal for small drifts in correlated trajectories.

  5. Crop insurance evaluation in response to extreme events

    Science.gov (United States)

    Moriondo, Marco; Ferrise, Roberto; Bindi, Marco

    2013-04-01

    Crop yield insurance has been indicated as a tool to manage the uncertainties of crop yields (Sherrick et al., 2004) but the changes in crop yield variability as expected in the near future should be carefully considered for a better quantitative assessment of farmer's revenue risk and insurance values in a climatic change regime (Moriondo et al., 2011). Under this point of view, mechanistic crop growth models coupled to the output of General/Regional Circulation Models (GCMs, RCMs) offer a valuable tool to evaluate crop responses to climatic change and this approach has been extensively used to describe crop yield distribution in response to climatic change considering changes in both mean climate and variability. In this work, we studied the effect of a warmer climate on crop yield distribution of durum wheat (Triticum turgidum L. subsp durum) in order to assess the economic significance of climatic change in a risk decision context. Specifically, the outputs of 6 RCMs (Tmin, Tmax, Rainfall, Global Radiation) (van der Linden and Mitchell 2009) have been statistically downscaled by a stochastic weather generator over eight sites across the Mediterranean basin and used to feed the crop growth model Sirius Quality. Three time slices were considered i) the present period PP (average of the period 1975-1990, [CO2]=350 ppm), 2020 (average of the period 2010-2030, SRES scenario A1b, [CO2]=415 ppm) and 2040 (average of the period 2030-2050, SRES scenario A1b, [CO2]=480 ppm). The effect of extreme climate events (i.e. heat stress at anthesis stage) was also considered. The outputs of these simulations were used to estimate the expected payout per hectare from insurance triggered when yields fall below a specific threshold defined as "the insured yield". For each site, the threshold was calculated as a fraction (70%) of the median of yield distribution under PP that represents the percentage of median yield above which indemnity payments are triggered. The results

  6. On the Probability of Occurrence of Extreme Space Weather Events

    Science.gov (United States)

    Riley, Pete

    2012-01-01

    By virtue of their rarity, extreme space weather events, such as the Carrington event of 1859, are difficult to study, their rates of occurrence are difficult to estimate, and prediction of a specific future event is virtually impossible. Additionally, events may be extreme relative to one parameter but normal relative to others. In this study, we analyze several measures of the severity of space weather events (flare intensity, coronal mass ejection speeds, Dst, and greater than 30 MeV proton fluences as inferred from nitrate records) to estimate the probability of occurrence of extreme events. By showing that the frequency of occurrence scales as an inverse power of the severity of the event, and assuming that this relationship holds at higher magnitudes, we are able to estimate the probability that an event larger than some criteria will occur within a certain interval of time in the future. For example, the probability of another Carrington event (based on Dst less than - 850 nT) occurring within the next decade is approximately 12%. We also identify and address several limitations with this approach. In particular, we assume time stationarity, and thus, the effects of long-term space climate change are not considered. While this technique cannot be used to predict specific events, it may ultimately be useful for probabilistic forecasting.

  7. On the Probability of Occurrence of Extreme Space Weather Events

    Science.gov (United States)

    Riley, Pete

    2012-01-01

    By virtue of their rarity, extreme space weather events, such as the Carrington event of 1859, are difficult to study, their rates of occurrence are difficult to estimate, and prediction of a specific future event is virtually impossible. Additionally, events may be extreme relative to one parameter but normal relative to others. In this study, we analyze several measures of the severity of space weather events (flare intensity, coronal mass ejection speeds, Dst, and greater than 30 MeV proton fluences as inferred from nitrate records) to estimate the probability of occurrence of extreme events. By showing that the frequency of occurrence scales as an inverse power of the severity of the event, and assuming that this relationship holds at higher magnitudes, we are able to estimate the probability that an event larger than some criteria will occur within a certain interval of time in the future. For example, the probability of another Carrington event (based on Dst less than - 850 nT) occurring within the next decade is approximately 12%. We also identify and address several limitations with this approach. In particular, we assume time stationarity, and thus, the effects of long-term space climate change are not considered. While this technique cannot be used to predict specific events, it may ultimately be useful for probabilistic forecasting.

  8. Extreme sea-level events in coastal regions

    Digital Repository Service at National Institute of Oceanography (India)

    Unnikrishnan, A.S.

    Simulation, Belur Campus, Bangalore 560 037, India e-mail: uns@cmmacs.ernet.in Extreme sea-level events in coastal regions A recently published report1 by the Intergovernmental Panel on Climate Change (IPCC) has made an assessment... of the extreme climate events. Their past trends, future projections and vulnerabi- lity and adaptation to such events are discussed in the report. The report was based on the efforts of both the working groups of the IPCC, WG I, which deals with the science...

  9. Geophysical Hazards and Preventive Disaster Management of Extreme Natural Events

    Science.gov (United States)

    Ismail-Zadeh, A.; Takeuchi, K.

    2007-12-01

    Geophysical hazard is potentially damaging natural event and/or phenomenon, which may cause the loss of life or injury, property damage, social and economic disruption, or environmental degradation. Extreme natural hazards are a key manifestation of the complex hierarchical nonlinear Earth system. An understanding, accurate modeling and forecasting of the extreme hazards are most important scientific challenges. Several recent extreme natural events (e.g., 2004 Great Indian Ocean Earthquake and Tsunami and the 2005 violent Katrina hurricane) demonstrated strong coupling between solid Earth and ocean, and ocean and atmosphere. These events resulted in great humanitarian tragedies because of a weak preventive disaster management. The less often natural events occur (and the extreme events are rare by definition), the more often the disaster managers postpone the preparedness to the events. The tendency to reduce the funding for preventive disaster management of natural catastrophes is seldom follows the rules of responsible stewardship for future generations neither in developing countries nor in highly developed economies where it must be considered next to malfeasance. Protecting human life and property against earthquake disasters requires an uninterrupted chain of tasks: from (i) understanding of physics of the events, analysis and monitoring, through (ii) interpretation, modeling, hazard assessment, and prediction, to (iii) public awareness, preparedness, and preventive disaster management.

  10. Multivariate Statistical Modelling of Drought and Heat Wave Events

    Science.gov (United States)

    Manning, Colin; Widmann, Martin; Vrac, Mathieu; Maraun, Douglas; Bevaqua, Emanuele

    2016-04-01

    Multivariate Statistical Modelling of Drought and Heat Wave Events C. Manning1,2, M. Widmann1, M. Vrac2, D. Maraun3, E. Bevaqua2,3 1. School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK 2. Laboratoire des Sciences du Climat et de l'Environnement, (LSCE-IPSL), Centre d'Etudes de Saclay, Gif-sur-Yvette, France 3. Wegener Center for Climate and Global Change, University of Graz, Brandhofgasse 5, 8010 Graz, Austria Compound extreme events are a combination of two or more contributing events which in themselves may not be extreme but through their joint occurrence produce an extreme impact. Compound events are noted in the latest IPCC report as an important type of extreme event that have been given little attention so far. As part of the CE:LLO project (Compound Events: muLtivariate statisticaL mOdelling) we are developing a multivariate statistical model to gain an understanding of the dependence structure of certain compound events. One focus of this project is on the interaction between drought and heat wave events. Soil moisture has both a local and non-local effect on the occurrence of heat waves where it strongly controls the latent heat flux affecting the transfer of sensible heat to the atmosphere. These processes can create a feedback whereby a heat wave maybe amplified or suppressed by the soil moisture preconditioning, and vice versa, the heat wave may in turn have an effect on soil conditions. An aim of this project is to capture this dependence in order to correctly describe the joint probabilities of these conditions and the resulting probability of their compound impact. We will show an application of Pair Copula Constructions (PCCs) to study the aforementioned compound event. PCCs allow in theory for the formulation of multivariate dependence structures in any dimension where the PCC is a decomposition of a multivariate distribution into a product of bivariate components modelled using copulas. A

  11. Extreme events in gross primary production: a characterization across continents

    Directory of Open Access Journals (Sweden)

    J. Zscheischler

    2014-01-01

    Full Text Available Climate extremes can affect the functioning of terrestrial ecosystems, for instance via a reduction of the photosynthetic capacity or alterations of respiratory processes. Yet the dominant regional and seasonal effects of hydrometeorological extremes are still not well documented. Here we quantify and characterize the role of large spatiotemporal extreme events in gross primary production (GPP as triggers of continental anomalies. We also investigate seasonal dynamics of extreme impacts on continental GPP anomalies. We find that the 50 largest positive (increase in uptake and negative extremes (decrease in uptake on each continent can explain most of the continental variation in GPP, which is in line with previous results obtained at the global scale. We show that negative extremes are larger than positive ones and demonstrate that this asymmetry is particularly strong in South America and Europe. Most extremes in GPP start in early summer. Our analysis indicates that the overall impacts and the spatial extents of GPP extremes are power law distributed with exponents that vary little across continents. Moreover, we show that on all continents and for all data sets the spatial extents play a more important role than durations or maximal GPP anomaly when it comes to the overall impact of GPP extremes. An analysis of possible causes implies that across continents most extremes in GPP can best be explained by water scarcity rather than by extreme temperatures. However, for Europe, South America and Oceania we identify also fire as an important driver. Our findings are consistent with remote sensing products. An independent validation against a literature survey on specific extreme events supports our results to a large extent.

  12. Extreme inflow events and synoptic forcing in Sydney catchments

    Energy Technology Data Exchange (ETDEWEB)

    Pepler, Acacia S; Rakich, Clinton S, E-mail: a.pepler@bom.gov.a [NSW Climate Services Section, Bureau of Meteorology PO Box 413, Darlinghurst, NSW 1300 (Australia)

    2010-08-15

    The Sydney catchment region encompasses over 16,000km{sup 2}, supplying water to over 4 million inhabitants. However, few studies have investigated the synoptic and climatic influences on inflow in this region, which are crucial for understanding the vulnerability of water supply in a changing climate. This study identifies extremely high and low inflow events between 1960 and 2008 based on catchment averages. The focus of the study is an analysis of the synoptic cause/s of each extreme inflow event. The events are evaluated to identify any trends and also to determine the concurrent significant climatic influences on rainfall over the catchments. Relationships between catchment inflow, rainfall, tropical SST indices, and other influencing factors such as observed wind and temperatures are investigated. Our results show that East Coast Lows and anomalously easterly flow are the drivers of high inflow events, with low inflow events dominated by westerly wind patterns and the El Nino-Southern Oscillation.

  13. Laws of small numbers extremes and rare events

    CERN Document Server

    Falk, Michael; Hüsler, Jürg

    2004-01-01

    Since the publication of the first edition of this seminar book in 1994, the theory and applications of extremes and rare events have enjoyed an enormous and still increasing interest. The intention of the book is to give a mathematically oriented development of the theory of rare events underlying various applications. This characteristic of the book was strengthened in the second edition by incorporating various new results on about 130 additional pages. Part II, which has been added in the second edition, discusses recent developments in multivariate extreme value theory. Particularly notable is a new spectral decomposition of multivariate distributions in univariate ones which makes multivariate questions more accessible in theory and practice. One of the most innovative and fruitful topics during the last decades was the introduction of generalized Pareto distributions in the univariate extreme value theory. Such a statistical modelling of extremes is now systematically developed in the multivariate fram...

  14. Probability distribution analysis of observational extreme events and model evaluation

    Science.gov (United States)

    Yu, Q.; Lau, A. K. H.; Fung, J. C. H.; Tsang, K. T.

    2016-12-01

    Earth's surface temperatures were the warmest in 2015 since modern record-keeping began in 1880, according to the latest study. In contrast, a cold weather occurred in many regions of China in January 2016, and brought the first snowfall to Guangzhou, the capital city of Guangdong province in 67 years. To understand the changes of extreme weather events as well as project its future scenarios, this study use statistical models to analyze on multiple climate data. We first use Granger-causality test to identify the attribution of global mean temperature rise and extreme temperature events with CO2 concentration. The four statistical moments (mean, variance, skewness, kurtosis) of daily maximum temperature distribution is investigated on global climate observational, reanalysis (1961-2010) and model data (1961-2100). Furthermore, we introduce a new tail index based on the four moments, which is a more robust index to measure extreme temperatures. Our results show that the CO2 concentration can provide information to the time series of mean and extreme temperature, but not vice versa. Based on our new tail index, we find that other than mean and variance, skewness is an important indicator should be considered to estimate extreme temperature changes and model evaluation. Among the 12 climate model data we investigate, the fourth version of Community Climate System Model (CCSM4) from National Center for Atmospheric Research performs well on the new index we introduce, which indicate the model have a substantial capability to project the future changes of extreme temperature in the 21st century. The method also shows its ability to measure extreme precipitation/ drought events. In the future we will introduce a new diagram to systematically evaluate the performance of the four statistical moments in climate model output, moreover, the human and economic impacts of extreme weather events will also be conducted.

  15. Changes in Extreme Events: from GCM Output to Social, Economic and Ecological Impacts

    Science.gov (United States)

    Tebaldi, C.; Meehl, G. A.

    2006-12-01

    Extreme events can deeply affect social and natural systems. The current generation of global climate model is producing information that can be directly used to characterize future changes in extreme events, and through a further step their impacts, despite their still relatively coarse resolution. It is important to define extreme indicators consistently with what we expect GCM to be able to represent reliably. We use two examples from our work, heat waves and frost days, that well describe different aspects of the analysis of extremes from GCM output. Frost days are "mild extremes" and their definition and computation is straightforward. GCMs can represent them accurately and display a strong consistent signal of change. The impacts of these changes will be extremely relevant for ecosystems and agriculture. Heat waves do not have a standard definition. On the basis of historical episodes we isolate characteristics that were responsible for the worst effects on human health, for example, and analyze these characteristics in model simulations, validating the model's historical simulations. The changes in these characteristics can then be easily translated in expected differential impacts on public health. Work in progress goes in the direction of better characterization of "heat waves" taking into account jointly a set of variables like maximum and minimum temperatures and humidity, better addressing the biological vulnerabilities of the populations at risk.

  16. 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

  17. 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.

  18. Present-day irrigation mitigates heat extremes

    Science.gov (United States)

    Thiery, Wim; Davin, Edouard L.; Lawrence, David M.; Hirsch, Annette L.; Hauser, Mathias; Seneviratne, Sonia I.

    2017-02-01

    Irrigation is an essential practice for sustaining global food production and many regional economies. Emerging scientific evidence indicates that irrigation substantially affects mean climate conditions in different regions of the world. Yet how this practice influences climate extremes is currently unknown. Here we use ensemble simulations with the Community Earth System Model to assess the impacts of irrigation on climate extremes. An evaluation of the model performance reveals that irrigation has a small yet overall beneficial effect on the representation of present-day near-surface climate. While the influence of irrigation on annual mean temperatures is limited, we find a large impact on temperature extremes, with a particularly strong cooling during the hottest day of the year (-0.78 K averaged over irrigated land). The strong influence on extremes stems from the timing of irrigation and its influence on land-atmosphere coupling strength. Together these effects result in asymmetric temperature responses, with a more pronounced cooling during hot and/or dry periods. The influence of irrigation is even more pronounced when considering subgrid-scale model output, suggesting that local effects of land management are far more important than previously thought. Our results underline that irrigation has substantially reduced our exposure to hot temperature extremes in the past and highlight the need to account for irrigation in future climate projections.

  19. Trends in Extremes of Surface Humidity, Temperature, and Summertime Heat Stress in China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In the past half century, the mean summertime temperature in China has increased, with nights warm ing more than days. Using surface station observations, we show that the frequency of extreme heat-stress events in China, caused by extremely hot and humid days as well as by heatwaves lasting for a few days, has increased over the period from 1951 to 1994. When humidity is high, hot weather can cause heat stress in humans. The increased heat-stress trend may pose a public health problem.

  20. Impacts of Extreme Events on Human Health. Chapter 4

    Science.gov (United States)

    Bell, Jesse E.; Herring, Stephanie C.; Jantarasami, Lesley; Adrianopoli, Carl; Benedict, Kaitlin; Conlon, Kathryn; Escobar, Vanessa; Hess, Jeremy; Luvall, Jeffrey; Garcia-Pando, Carlos Perez; Quattrochi, Dale; Runkle, Jennifer; Schreck, Carl J., III

    2016-01-01

    Increased Exposure to Extreme Events Key Finding 1: Health impacts associated with climate-related changes in exposure to extreme events include death, injury, or illness; exacerbation of underlying medical conditions; and adverse effects on mental health[High Confidence]. Climate change will increase exposure risk in some regions of the United States due to projected increases in the frequency and/or intensity of drought, wildfires, and flooding related to extreme precipitation and hurricanes [Medium Confidence].Disruption of Essential Infrastructure Key Finding 2: Many types of extreme events related to climate change cause disruption of infrastructure, including power, water, transportation, and communication systems, that are essential to maintaining access to health care and emergency response services and safeguarding human health [High Confidence].Vulnerability to Coastal Flooding Key Finding 3: Coastal populations with greater vulnerability to health impacts from coastal flooding include persons with disabilities or other access and functional needs, certain populations of color, older adults, pregnant women and children, low-income populations, and some occupational groups [High Confidence].Climate change will increase exposure risk to coastal flooding due to increases in extreme precipitation and in hurricane intensity and rainfall rates, as well as sea level rise and the resulting increases in storm surge.

  1. The Integrated periodogram of a dependent extremal event sequence

    DEFF Research Database (Denmark)

    Mikosch, Thomas Valentin; Zhao, Yuwei

    2015-01-01

    We investigate the asymptotic properties of the integrated periodogram calculated from a sequence of indicator functions of dependent extremal events. An event in Euclidean space is extreme if it occurs far away from the origin. We use a regular variation condition on the underlying stationary.......i.d. case a Brownian bridge appears. In the general case, we propose a stationary bootstrap procedure for approximating the distribution of the limiting process. The developed theory can be used to construct classical goodness-of-fit tests such as the Grenander–Rosenblatt and Cramér–von Mises tests which...... are based only on the extremes in the sample. We apply the test statistics to simulated and real-life data....

  2. What is the right way to talk about extreme events?

    Science.gov (United States)

    Sobel, A. H.

    2013-12-01

    Extreme weather events draw the attention of the public. By demonstrating the vulnerability of human society to climate, extreme events can cause nonscientists -government leaders as well as the broader population - to take the danger posed by anthropogenic global warming more seriously than they otherwise might. An extreme event that draws media attention can become a 'teachable moment'. But extreme events are difficult to talk about in a way that honors both the strengths and weaknesses of the underlying science. No single event can be attributed to climate change, and some types of events are not even clearly influenced by it (or not in any ways our science can yet demonstrate). Strong, media-friendly statements that closely connect specific events to climate - designed to make best use of the moment's teachability - can easily overstate the case. This will raise the hackles of one's colleagues, at a minimum, and at worst, may damage the credibility of the field more broadly. Yet talking too much about the uncertainties runs the risk of understating the basic truth that global warming is real and dangerous, and may lend inadvertent support to anti-scientific denialism. I will discuss this tension in the context of my own experiences in the media after 'Superstorm' Sandy. I will address arguments I have heard, from social scientists and media consultants, to the effect that climate scientists should adopt communications strategies that lead to stronger, more media-friendly statements, and learn to suppress the tendency, bred into us during our scientific training, to emphasize the uncertainties.

  3. 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.

  4. Prediction of a thermodynamic wave train from the monsoon to the Arctic following extreme rainfall events

    Science.gov (United States)

    Krishnamurti, T. N.; Kumar, Vinay

    2016-06-01

    This study addresses numerical prediction of atmospheric wave trains that provide a monsoonal link to the Arctic ice melt. The monsoonal link is one of several ways that heat is conveyed to the Arctic region. This study follows a detailed observational study on thermodynamic wave trains that are initiated by extreme rain events of the northern summer south Asian monsoon. These wave trains carry large values of heat content anomalies, heat transports and convergence of flux of heat. These features seem to be important candidates for the rapid melt scenario. This present study addresses numerical simulation of the extreme rains, over India and Pakistan, and the generation of thermodynamic wave trains, simulations of large heat content anomalies, heat transports along pathways and heat flux convergences, potential vorticity and the diabatic generation of potential vorticity. We compare model based simulation of many features such as precipitation, divergence and the divergent wind with those evaluated from the reanalysis fields. We have also examined the snow and ice cover data sets during and after these events. This modeling study supports our recent observational findings on the monsoonal link to the rapid Arctic ice melt of the Canadian Arctic. This numerical modeling suggests ways to interpret some recent episodes of rapid ice melts that may require a well-coordinated field experiment among atmosphere, ocean, ice and snow cover scientists. Such a well-coordinated study would sharpen our understanding of this one component of the ice melt, i.e. the monsoonal link, which appears to be fairly robust.

  5. Prediction of a thermodynamic wave train from the monsoon to the Arctic following extreme rainfall events

    Science.gov (United States)

    Krishnamurti, T. N.; Kumar, Vinay

    2017-04-01

    This study addresses numerical prediction of atmospheric wave trains that provide a monsoonal link to the Arctic ice melt. The monsoonal link is one of several ways that heat is conveyed to the Arctic region. This study follows a detailed observational study on thermodynamic wave trains that are initiated by extreme rain events of the northern summer south Asian monsoon. These wave trains carry large values of heat content anomalies, heat transports and convergence of flux of heat. These features seem to be important candidates for the rapid melt scenario. This present study addresses numerical simulation of the extreme rains, over India and Pakistan, and the generation of thermodynamic wave trains, simulations of large heat content anomalies, heat transports along pathways and heat flux convergences, potential vorticity and the diabatic generation of potential vorticity. We compare model based simulation of many features such as precipitation, divergence and the divergent wind with those evaluated from the reanalysis fields. We have also examined the snow and ice cover data sets during and after these events. This modeling study supports our recent observational findings on the monsoonal link to the rapid Arctic ice melt of the Canadian Arctic. This numerical modeling suggests ways to interpret some recent episodes of rapid ice melts that may require a well-coordinated field experiment among atmosphere, ocean, ice and snow cover scientists. Such a well-coordinated study would sharpen our understanding of this one component of the ice melt, i.e. the monsoonal link, which appears to be fairly robust.

  6. Exploring the causes of rare extreme precipitation events

    Science.gov (United States)

    Schroeer, Katharina; Kirchengast, Gottfried

    2015-04-01

    Whereas trends of precipitation changes in general are disparate, an increase of extreme intensities of short precipitation events (daily to sub-hourly scale) with increasing temperatures seems unambiguous (e.g. Trenberth et al., Clim. Res. 47, 123-138, 2011; Berg et al., Nat. Clim. Change 13, 181-185, 2013; Kendon et al., Nat. Clim. Change 4, 570-576, 2014). In probability density functions (PDFs) of observed precipitation intensities that are frequently used in science and practice, high magnitude ("extreme") low frequency ("rare") precipitation events naturally appear at the tails of PDFs. Due to the factual data scarcity, rare extreme events ("REEs") are difficult to come by with statistical analyses. Amongst studies of extreme precipitation, statistical work nevertheless makes a major contribution to the research field. Usually as a first step, a threshold is defined to classify extreme events out of a sample (statistical extreme events, "SEEs"), where methods are affected by the sample size. Such thresholds can be described user-defined or constructed. Subsequently, a PDF is sought, fit and applied (e.g. Yilmaz et al., Hydrol. Earth Syst. Sci. 18, 4065-4076, 2014;, Papalexiou et al., Hydrol. Earth Syst. Sci. 17, 851-862, 2013). While these studies respond to the needs of engeneering practice in e.g. infrastructure design, or trend analysis of precipitation in climate studies, they a) have to ignore REEs because of practical or statistical/data limitations (i.e. left out as "residual risk") and b) tell us little about the underlying processes of the climate and weather system causing REEs. We define REEs in contrast to SEEs as to be of such occurrence that they cannot be sufficiently described nor predicted by means of a regular or fat-tailed PDF. We introduce a working hypothesis assuming that REEs are conditioned and caused by a conjunction of specific circumstances on different scales. We differentiate spatio-temporal circumstances of large

  7. Methodology for assessing probability of extreme hydrologic events coincidence

    Directory of Open Access Journals (Sweden)

    Prohaska Stevan

    2010-01-01

    Full Text Available The aim of the presented research is improvement of methodology for probability calculation of coinciding occurrence of historic floods and droughts in the same year. The original procedure was developed in order to determine the occurrence probability of such an extreme historic event. There are two phases in calculation procedure for assessment of both extreme drought and flood occurrence probability in the same year. In the first phase outliers are detected as indicators of extreme events, their return periods are calculated and series' statistics adjusted. In the second phase conditional probabilities are calculated: empirical points are plotted, and both extreme drought and flood occurrence probability in the same year is assessed based on the plot. Outlier detection is performed for the territory of Serbia. Results are shown as maps of regions (basins prone to floods, hydrologic drought, or both. Step-by-step numeric example is given for assessing conditional probability of occurrence of flood and drought for GS Raska on the river Raska. Results of assessment of conditional probability in two more cases are given for combination of extreme flood and 30 day minimum flow.

  8. Reproducing an extreme flood with uncertain post-event information

    Science.gov (United States)

    Fuentes-Andino, Diana; Beven, Keith; Halldin, Sven; Xu, Chong-Yu; Reynolds, José Eduardo; Di Baldassarre, Giuliano

    2017-07-01

    Studies for the prevention and mitigation of floods require information on discharge and extent of inundation, commonly unavailable or uncertain, especially during extreme events. This study was initiated by the devastating flood in Tegucigalpa, the capital of Honduras, when Hurricane Mitch struck the city. In this study we hypothesized that it is possible to estimate, in a trustworthy way considering large data uncertainties, this extreme 1998 flood discharge and the extent of the inundations that followed from a combination of models and post-event measured data. Post-event data collected in 2000 and 2001 were used to estimate discharge peaks, times of peak, and high-water marks. These data were used in combination with rain data from two gauges to drive and constrain a combination of well-known modelling tools: TOPMODEL, Muskingum-Cunge-Todini routing, and the LISFLOOD-FP hydraulic model. Simulations were performed within the generalized likelihood uncertainty estimation (GLUE) uncertainty-analysis framework. The model combination predicted peak discharge, times of peaks, and more than 90 % of the observed high-water marks within the uncertainty bounds of the evaluation data. This allowed an inundation likelihood map to be produced. Observed high-water marks could not be reproduced at a few locations on the floodplain. Identifications of these locations are useful to improve model set-up, model structure, or post-event data-estimation methods. Rainfall data were of central importance in simulating the times of peak and results would be improved by a better spatial assessment of rainfall, e.g. from radar data or a denser rain-gauge network. Our study demonstrated that it was possible, considering the uncertainty in the post-event data, to reasonably reproduce the extreme Mitch flood in Tegucigalpa in spite of no hydrometric gauging during the event. The method proposed here can be part of a Bayesian framework in which more events can be added into the analysis as

  9. Extreme flood events in the Dead Sea basin

    Science.gov (United States)

    Ahlborn, Marieke; Ben Dor, Yoav; Schwab, Markus J.; Neugebauer, Ina; Plessen, Birgit; Tjallingii, Rik; Erel, Yigal; Enzel, Yehouda; Brauer, Achim

    2016-04-01

    The Dead Sea is a hypersaline, terminal lake located within the Dead Sea basin at the lowest continental elevation on Earth (~425 m below mean sea level). Extreme hydro-meteorological events in terms of flash floods occur regularly during the wet season in the Dead Sea basin and adjacent mountain ranges. However, little is known about the impact of these extreme floods on the sedimentary dynamics in the Dead Sea and possible links to long-term climate changes. The trilateral research project PALEX (Paleoclimate in the Eastern Mediterranean Region - Levante: Paleohydrology and Extreme Flood Events) was recently initiated within the framework of the DFG priority program 1006 ICDP (International Continental Scientific Drilling Program) to investigate extreme flood events in the Dead Sea basin during the Late Pleistocene and Holocene. Within the ICDP Dead Sea Deep Drilling Project (DSDDP) the ~455 m long sediment core 5017-1 was recovered from the northern Dead Sea basin. Previously published results (Neugebauer et al., 2014, 2015) have demonstrated the occurrence of extreme flood events represented in the sediments as thick graded detrital layers during Late Holocene dry phases. Based on these results we will apply a comprehensive analytical approach including microfacies analyses, μXRF element scanning, and stable isotope geochemistry to different time intervals of core 5017-1. Particularly, we aim to investigate the structure and composition of detrital layers in order to decipher sediment transport mechanisms and the provenance of the flood-triggered sediments. The overarching goal is to establish a high-resolution extreme flood time series for the Dead Sea basin on the basis of a previously established radiocarbon and U-Th chronology (Torfstein et al., 2015; Neugebauer et al., 2014) and to study a possible link between the frequency and magnitude of extreme flood events and the long-term climate trend. Neugebauer I, Brauer A, Schwab MJ, et al. (2014) Lithology of

  10. Investigation on rainfall extremes events trough a geoadditive model

    Science.gov (United States)

    Bocci, C.; Caporali, E.; Petrucci, A.; Rossi, G.

    2012-04-01

    Rainfall can be considered a very important variable, and rainfall extreme events analysis of great concern for the enormous impacts that they may have on everyday life particularly when related to intense rainfalls and floods, and hydraulic risk management. On the catchment area of Arno River in Tuscany, Central Italy, a geoadditive mixed model of rainfall extremes is developed. Most of the territory of Arno River has suffered in the past of many severe hydro-geological events, with high levels of risk due to the vulnerability of a unique artistic and cultural heritage. The area has a complex topography that greatly influences the precipitation regime. The dataset is composed by the time series of the annual maxima of daily rainfall recorded in about 400 rain gauges, spatially distributed over the catchment area of about 8.800 km2. The record period covers mainly the second half of 20th century. The rainfall observations are assumed to follow generalized extreme value distributions whose locations are spatially dependent and where the dependence is captured using a geoadditive model. In particular, since rainfall has a natural spatial domain and a significant spatial variability, a spatial hierarchical model for extremes is used. The spatial hierarchical models, in fact, take into account data from all locations, borrowing strength from neighbouring locations when they estimate parameters and are of great interest when small set of data is available, as in the case of rainfall extreme values. Together with rain gauges location variables further physiographic variables are investigated as explanation variables. The implemented geoadditive mixed model of spatially referenced time series of rainfall extreme values, is able to capture the spatial dynamics of the rainfall extreme phenomenon. Since the model shows evidence of a spatial trend in the rainfall extreme dynamic, the temporal dynamic and the time influence can be also taken into account. The implemented

  11. Temporal variation of extreme precipitation events in Lithuania

    Directory of Open Access Journals (Sweden)

    Egidijus Rimkus

    2011-05-01

    Full Text Available Heavy precipitation events in Lithuania for the period 1961-2008 were analysed. The spatial distribution and dynamics of precipitation extremes were investigated. Positive tendencies and in some cases statistically significant trends were determined for the whole of Lithuania. Atmospheric circulation processes were derived using Hess & Brezowski's classification of macrocirculation forms. More than one third of heavy precipitation events (37% were observed when the atmospheric circulation was zonal. The location of the central part of a cyclone (WZ weather condition subtype over Lithuania is the most common synoptic situation (27% during heavy precipitation events. Climatic projections according to outputs of the CCLM model are also presented in this research. The analysis shows that the recurrence of heavy precipitation events in the 21st century will increase significantly (by up to 22% in Lithuania.

  12. High resolution modelling of extreme precipitation events in urban areas

    Science.gov (United States)

    Siemerink, Martijn; Volp, Nicolette; Schuurmans, Wytze; Deckers, Dave

    2015-04-01

    The present day society needs to adjust to the effects of climate change. More extreme weather conditions are expected, which can lead to longer periods of drought, but also to more extreme precipitation events. Urban water systems are not designed for such extreme events. Most sewer systems are not able to drain the excessive storm water, causing urban flooding. This leads to high economic damage. In order to take appropriate measures against extreme urban storms, detailed knowledge about the behaviour of the urban water system above and below the streets is required. To investigate the behaviour of urban water systems during extreme precipitation events new assessment tools are necessary. These tools should provide a detailed and integral description of the flow in the full domain of overland runoff, sewer flow, surface water flow and groundwater flow. We developed a new assessment tool, called 3Di, which provides detailed insight in the urban water system. This tool is based on a new numerical methodology that can accurately deal with the interaction between overland runoff, sewer flow and surface water flow. A one-dimensional model for the sewer system and open channel flow is fully coupled to a two-dimensional depth-averaged model that simulates the overland flow. The tool uses a subgrid-based approach in order to take high resolution information of the sewer system and of the terrain into account [1, 2]. The combination of using the high resolution information and the subgrid based approach results in an accurate and efficient modelling tool. It is now possible to simulate entire urban water systems using extreme high resolution (0.5m x 0.5m) terrain data in combination with a detailed sewer and surface water network representation. The new tool has been tested in several Dutch cities, such as Rotterdam, Amsterdam and The Hague. We will present the results of an extreme precipitation event in the city of Schiedam (The Netherlands). This city deals with

  13. Hypersonic Composites Resist Extreme Heat and Stress

    Science.gov (United States)

    2007-01-01

    Through research contracts with NASA, Materials and Electrochemical Research Corporation (MER), of Tucson, Arizona, contributed a number of technologies to record-breaking hypersonic flights. Through this research, MER developed a coating that successfully passed testing to simulate Mach 10 conditions, as well as provide several additional carbon-carbon (C-C) composite components for the flights. MER created all of the leading edges for the X-43A test vehicles at Dryden-considered the most critical parts of this experimental craft. In addition to being very heat resistant, the coating had to be very lightweight and thin, as the aircraft was designed to very precise specifications and could not afford to have a bulky coating. MER patented its carbon-carbon (C-C) composite process and then formed a spinoff company, Frontier Materials Corporation (FMC), also based in Tucson. FMC is using the patent in conjunction with low-cost PAN (polyacrylonitrile)-based fibers to introduce these materials to the commercial markets. The C-C composites are very lightweight and exceptionally strong and stiff, even at very high temperatures. The composites have been used in industrial heating applications, the automotive and aerospace industries, as well as in glass manufacturing and on semiconductors. Applications also include transfer components for glass manufacturing and structural members for carrier support in semiconductor processing.

  14. 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)

  15. 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

  16. Distributing urban resilience to extreme precipitation events with green infrastructure

    Science.gov (United States)

    Montalto, F. A.; Catalano De Sousa, M.; Yu, Z.

    2013-12-01

    New urban green spaces are being designed to manage stormwater, but their performance in a changing climate is untested. Key questions pertain to the ability of these systems to mitigate flood and sewer overflow concerns during impact of extreme events on, and to withstand (biologically and physically) increased frequency and intensity of drought and flood conditions. In this presentation, we present field data characterizing performance of a bioretention area, a stormwater treatment wetland, and a green roof under Hurricane Irene (2011), Superstorm Sandy (2012), and a variety of extreme precipitation events during the summer of 2013. Specifically, we characterize the fate and volume of incident runon and/or precipitation to the facilities during these extreme events, and compare them to long term monitored performance metrics. We also present laboratory test results documenting how vegetation in these facilities stands up to simulated flood and drought conditions. The results are discussed in the context of predicted climate change, specifically associated with the amount and timing of precipitation.

  17. 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.

  18. Urban-Induced Mechanisms for an Extreme Rainfall Event in Beijing China: A Satellite Perspective

    Directory of Open Access Journals (Sweden)

    Menglin S. Jin

    2015-03-01

    Full Text Available Using 1 km satellite remote sensing observations, this paper examines the clouds, aerosols, water vapor and surface skin temperature over Beijing to understand the possible urban system contributions to the extreme rainfall event on 21 July 2012 (i.e., 721 event. Remote sensing measurements, with the advantage of high spatial resolution and coverage, reveal three key urban-related mechanisms: (a the urban heat island effect (UHI resulted in strong surface convection and high level cloud cover over Beijing; (b urban aerosol amount peaked before the rainfall, which “seeded” the clouds and invigorated precipitation; and (c urban tall buildings provided additional lift for the air mass and provided heat at the underlying boundary to keep the rainfall system alive for a long duration precipitation (>10 hours. With the existing rainfall system moving from the northwest and abundant water vapor was transported from the southeast into Beijing, the urban canyon-lifting, aerosol, and UHI effects all enhanced this extreme rainfall event. This work proves that urban system is responsible, at least partly, for urban rainfall extremes and thus should be considered for urban extreme rainfall prediction in the future.

  19. Understanding extreme rainfall events in Australia through historical data

    Science.gov (United States)

    Ashcroft, Linden; Karoly, David John

    2016-04-01

    Historical climate data recovery is still an emerging field in the Australian region. The majority of Australia's instrumental climate analyses begin in 1900 for rainfall and 1910 for temperature, particularly those focussed on extreme event analysis. This data sparsity for the past in turn limits our understanding of long-term climate variability, constraining efforts to predict the impact of future climate change. To address this need for improved historical data in Australia, a new network of recovered climate observations has recently been developed, centred on the highly populated southeastern Australian region (Ashcroft et al., 2014a, 2014b). The dataset includes observations from more than 39 published and unpublished sources and extends from British settlement in 1788 to the formation of the Australian Bureau of Meteorology in 1908. Many of these historical sources provide daily temperature and rainfall information, providing an opportunity to improve understanding of the multidecadal variability of Australia's extreme events. In this study we combine the historical data for three major Australian cities - Melbourne, Sydney and Adelaide - with modern observations to examine extreme rainfall variability over the past 174 years (1839-2013). We first explore two case studies, combining instrumental and documentary evidence to support the occurrence of severe storms in Sydney in 1841 and 1844. These events appear to be at least as extreme as Sydney's modern 24-hour rainfall record. Next we use a suite of rainfall indices to assess the long-term variability of rainfall in southeastern Australia. In particular, we focus on the stationarity of the teleconnection between the El Niño-Southern Oscillation (ENSO) phenomenon and extreme rainfall events. Using ENSO reconstructions derived from both palaeoclimatic and documentary sources, we determine the historical relationship between extreme rainfall in southeastern Australia and ENSO, and examine whether or not this

  20. Reliability of structural systems subjected to extreme forcing events

    CERN Document Server

    Joo, Han-Kyul; Sapsis, Themistoklis P

    2016-01-01

    We characterize the complex, heavy-tailed probability distribution functions (pdf) describing the response and its local extrema for structural systems subjected to random forcing that includes extreme events. Our approach is based on the recent probabilistic decomposition-synthesis technique in, where we decouple rare events regimes from the background fluctuations. The result of the analysis has the form of a semi-analytical approximation formula for the pdf of the response (displacement, velocity, and acceleration) and the pdf of the local extrema. For special limiting cases (lightly damped or heavily damped systems) our analysis provides fully analytical approximations. We also demonstrate how the method can be applied to high dimensional structural systems through a two-degrees-of-freedom structural system undergoing rare events due to intermittent forcing. The derived formulas can be evaluated with very small computational cost and are shown to accurately capture the complicated heavy-tailed and asymmet...

  1. Impacts of extreme weather events on transport infrastructure in Norway

    Science.gov (United States)

    Frauenfelder, Regula; Solheim, Anders; Isaksen, Ketil; Romstad, Bård; Dyrrdal, Anita V.; Ekseth, Kristine H. H.; Gangstø Skaland, Reidun; Harbitz, Alf; Harbitz, Carl B.; Haugen, Jan E.; Hygen, Hans O.; Haakenstad, Hilde; Jaedicke, Christian; Jónsson, Árni; Klæboe, Ronny; Ludvigsen, Johanna; Meyer, Nele K.; Rauken, Trude; Sverdrup-Thygeson, Kjetil

    2016-04-01

    With the latest results on expected future increase in air temperature and precipitation changes reported by the Intergovernmental Panel on Climate Change (IPCC), the climate robustness of important infrastructure is of raising concern in Norway, as well as in the rest of Europe. Economic consequences of natural disasters have increased considerably since 1950. In addition to the effect of demographic changes such as population growth, urbanization and more and more concentration of valuable assets, this increase is also related to an augmenting frequency of extreme events, such as storms, flooding, drought, and landslides. This change is also observable in Norway, where the increased frequency of strong precipitation has led to frequent flooding and landslide events during the last 20 years. A number of studies show that climate change causes an increase in both frequency and intensity of several types of extreme weather, especially when it comes to precipitation. Such extreme weather events greatly affect the transport infrastructure, with numerous and long closures of roads and railroads, in addition to damage and repair costs. Frequent closures of railroad and roads lead to delay or failure in delivery of goods, which again may lead to a loss of customers and/or - eventually - markets. Much of the Norwegian transport infrastructure is more than 50 years old and therefore not adequately dimensioned, even for present climatic conditions. In order to assess these problems and challenges posed to the Norwegian transport infrastructure from present-day and future extreme weather events, the project "Impacts of extreme weather events on infrastructure in Norway (InfraRisk)" was performed under the research Council of Norway program 'NORKLIMA', between 2009 and 2013. The main results of the project are: - Moderate to strong precipitation events have become more frequent and more intense in Norway over the last 50 years, and this trend continues throughout the 21st

  2. 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.

  3. Analogues of atmospheric circulation to probe extreme and rare events

    Science.gov (United States)

    Yiou, P.

    2015-12-01

    Analogues of atmospheric circulation have had many applications, from weather prediction to the downscaling of climate variables. The main assumptions behind this methodology are that climate variables (such as temperature or precipitation) are linked a large-scale atmospheric predictand, which is usually taken as sea-level pressure, and that such predictands recur through time. They offer a possibility to estimate probability distributions of a climate variable, conditional to patterns of atmospheric circulation. In addition, this methodology allows the quantification of unusual weather patterns that have been observed. I will represent a way to use analogues of circulation for the detection/attribution of extreme events of precipitation and temperature. This approach will be illustrated on test cases, including the warm European winter of 2006/2007, the extremes of precipitation over Southern UK and northwestern France in January 2014, and the European summer of 2015. I will show how this analysis provides a low-cost estimate of the fraction of attributable risk (FAR) for extreme events that verify the above mentioned hypotheses. Such an analysis can be performed in continuous time with reanalysis data and meteorological observations.

  4. Reproducing an extreme flood with uncertain post-event information

    Directory of Open Access Journals (Sweden)

    D. Fuentes-Andino

    2017-07-01

    Full Text Available Studies for the prevention and mitigation of floods require information on discharge and extent of inundation, commonly unavailable or uncertain, especially during extreme events. This study was initiated by the devastating flood in Tegucigalpa, the capital of Honduras, when Hurricane Mitch struck the city. In this study we hypothesized that it is possible to estimate, in a trustworthy way considering large data uncertainties, this extreme 1998 flood discharge and the extent of the inundations that followed from a combination of models and post-event measured data. Post-event data collected in 2000 and 2001 were used to estimate discharge peaks, times of peak, and high-water marks. These data were used in combination with rain data from two gauges to drive and constrain a combination of well-known modelling tools: TOPMODEL, Muskingum–Cunge–Todini routing, and the LISFLOOD-FP hydraulic model. Simulations were performed within the generalized likelihood uncertainty estimation (GLUE uncertainty-analysis framework. The model combination predicted peak discharge, times of peaks, and more than 90 % of the observed high-water marks within the uncertainty bounds of the evaluation data. This allowed an inundation likelihood map to be produced. Observed high-water marks could not be reproduced at a few locations on the floodplain. Identifications of these locations are useful to improve model set-up, model structure, or post-event data-estimation methods. Rainfall data were of central importance in simulating the times of peak and results would be improved by a better spatial assessment of rainfall, e.g. from radar data or a denser rain-gauge network. Our study demonstrated that it was possible, considering the uncertainty in the post-event data, to reasonably reproduce the extreme Mitch flood in Tegucigalpa in spite of no hydrometric gauging during the event. The method proposed here can be part of a Bayesian framework in which more events

  5. The Estimation of Probability of Extreme Events for Small Samples

    Science.gov (United States)

    Pisarenko, V. F.; Rodkin, M. V.

    2017-02-01

    The most general approach to the study of rare extreme events is based on the extreme value theory. The fundamental General Extreme Value Distribution lies in the basis of this theory serving as the limit distribution for normalized maxima. It depends on three parameters. Usually the method of maximum likelihood (ML) is used for the estimation that possesses well-known optimal asymptotic properties. However, this method works efficiently only when sample size is large enough ( 200-500), whereas in many applications the sample size does not exceed 50-100. For such sizes, the advantage of the ML method in efficiency is not guaranteed. We have found that for this situation the method of statistical moments (SM) works more efficiently over other methods. The details of the estimation for small samples are studied. The SM is applied to the study of extreme earthquakes in three large virtual seismic zones, representing the regime of seismicity in subduction zones, intracontinental regime of seismicity, and the regime in mid-ocean ridge zones. The 68%-confidence domains for pairs of parameter (ξ, σ) and (σ, μ) are derived.

  6. The heat wave of August 2012 in the Czech Republic: Evaluation using the Weather Extremity Index

    Science.gov (United States)

    Holtanová, Eva; Valeriánová, Anna; Crhová, Lenka

    2014-05-01

    We present an analysis of the summer heat wave of August 2012 in the Czech Republic. We use and compare results of two different approaches to heat wave evaluation. The Weather Extremity Index evaluates the extremity and spatial extent of the meteorological extreme event of interest. The second method is based on the duration of daily maximum air temperature above specific thresholds. In August 2012, the high air temperature in the Czech Republic lasted from 18/8 to 24/8. It was connected with the inflow of hot air from northern Africa between the low pressure trough over the eastern Atlantic and the region of high pressure in central Europe. The heat wave culminated on 20/8 when the maximum air temperature was higher than 30°C in the whole area of the Czech Republic and the highest daily maximum air temperature on record in the Czech Republic with value of 40.4°C was observed at Dobřichovice station. Our results demonstrate that the studied heat wave was quite extraordinary, occurring so late in the summer with a relatively large areal extent and extremity of detected maximum air temperature. Furthermore, the Weather Extremity Index was found useful for identification of really extreme high air temperature events and facilitated inter-comparison in terms of extremity and spatial extent. However, it cannot be used for detection of all heat waves that could have severe impacts on both human activities and natural ecosystems. The work has been supported by the grant P209/11/1990 funded by the Czech Science Foundation.

  7. Associating emergency room visits with first and prolonged extreme temperature event in Taiwan: A population-based cohort study.

    Science.gov (United States)

    Wang, Yu-Chun; Lin, Yu-Kai; Chuang, Chun-Yu; Li, Ming-Hsu; Chou, Chang-Hung; Liao, Chun-Hui; Sung, Fung-Chang

    2012-02-01

    The present study evaluated emergency room visit (ERV) risks for all causes and cardiopulmonary diseases associated with temperature and long-lasting extreme temperatures from 2000 to 2009 in four major cities in Taiwan. The city-specific daily average temperatures at the high 95th, 97th, and 99th percentiles, and the low 10th, 5th, and 1st percentiles were defined as extreme heat and cold. A distributed lag non-linear model was used to estimate the cumulative relative risk (RR) of ERV for morbidities associated with temperatures (0 to 3-day lags), extreme heat and cold lasting for 2 to 9 days or longer, and with the annual first extreme heat or cold event after controlling for covariates. Low temperatures were associated with slightly higher ERV risks than high temperatures for circulatory diseases. After accounting for 4-day cumulative temperature effect, the ERV risks for all causes and respiratory diseases were found to be associated with extreme cold at the 5th percentile lasting for >8 days and 1st percentile lasting for >3 days. The annual first extreme cold event of 5th percentile or lower temperatures was also significantly associated with ERV, with RRs ranging from 1.09 to 1.12 for all causes and from 1.15 to 1.26 for respiratory diseases. The annual first extreme heat event of 99th percentile temperature was associated with higher ERV for all causes and circulatory diseases. Annual first extreme temperature event and intensified prolonged extreme cold events are associated with increased ERVs in Taiwan.

  8. 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.

  9. Probabilistic forecast of daily areal precipitation focusing on extreme events

    Science.gov (United States)

    Bliefernicht, J.; Bárdossy, A.

    2007-04-01

    A dynamical downscaling scheme is usually used to provide a short range flood forecasting system with high-resolved precipitation fields. Unfortunately, a single forecast of this scheme has a high uncertainty concerning intensity and location especially during extreme events. Alternatively, statistical downscaling techniques like the analogue method can be used which can supply a probabilistic forecasts. However, the performance of the analogue method is affected by the similarity criterion, which is used to identify similar weather situations. To investigate this issue in this work, three different similarity measures are tested: the euclidean distance (1), the Pearson correlation (2) and a combination of both measures (3). The predictor variables are geopotential height at 1000 and 700 hPa-level and specific humidity fluxes at 700 hPa-level derived from the NCEP/NCAR-reanalysis project. The study is performed for three mesoscale catchments located in the Rhine basin in Germany. It is validated by a jackknife method for a period of 44 years (1958-2001). The ranked probability skill score, the Brier Skill score, the Heidke skill score and the confidence interval of the Cramer association coefficient are calculated to evaluate the system for extreme events. The results show that the combined similarity measure yields the best results in predicting extreme events. However, the confidence interval of the Cramer coefficient indicates that this improvement is only significant compared to the Pearson correlation but not for the euclidean distance. Furthermore, the performance of the presented forecasting system is very low during the summer and new predictors have to be tested to overcome this problem.

  10. Radiative heat transfer in the extreme near field.

    Science.gov (United States)

    Kim, Kyeongtae; Song, Bai; Fernández-Hurtado, Víctor; Lee, Woochul; Jeong, Wonho; Cui, Longji; Thompson, Dakotah; Feist, Johannes; Reid, M T Homer; García-Vidal, Francisco J; Cuevas, Juan Carlos; Meyhofer, Edgar; Reddy, Pramod

    2015-12-17

    Radiative transfer of energy at the nanometre length scale is of great importance to a variety of technologies including heat-assisted magnetic recording, near-field thermophotovoltaics and lithography. Although experimental advances have enabled elucidation of near-field radiative heat transfer in gaps as small as 20-30 nanometres (refs 4-6), quantitative analysis in the extreme near field (less than 10 nanometres) has been greatly limited by experimental challenges. Moreover, the results of pioneering measurements differed from theoretical predictions by orders of magnitude. Here we use custom-fabricated scanning probes with embedded thermocouples, in conjunction with new microdevices capable of periodic temperature modulation, to measure radiative heat transfer down to gaps as small as two nanometres. For our experiments we deposited suitably chosen metal or dielectric layers on the scanning probes and microdevices, enabling direct study of extreme near-field radiation between silica-silica, silicon nitride-silicon nitride and gold-gold surfaces to reveal marked, gap-size-dependent enhancements of radiative heat transfer. Furthermore, our state-of-the-art calculations of radiative heat transfer, performed within the theoretical framework of fluctuational electrodynamics, are in excellent agreement with our experimental results, providing unambiguous evidence that confirms the validity of this theory for modelling radiative heat transfer in gaps as small as a few nanometres. This work lays the foundations required for the rational design of novel technologies that leverage nanoscale radiative heat transfer.

  11. PRACE resources to study extreme natural events: the SCENE project

    Science.gov (United States)

    Fiori, Elisabetta; Galizia, Antonella; Danovaro, Emanuele; Clematis, Andrea; Bedrina, Tatiana; Parodi, Antonio

    2014-05-01

    Forecasting severe storms and floods is one of the main challenges of 21th century. Floods are the most dangerous meteorological hazard in the Mediterranean basins due to both the number of people affected and to the relatively high frequency by which human activities and goods suffer damages and losses. The numerical simulations of extreme events which happen over small basins as the Mediterranean ones are need a very fine-resolution in space and time and as a consequence considerable memory and computational power are required. Since the resources provided by the PRACE project represent the solution for satisfying such requirements, the Super Computing of Extreme Natural Events (SCENE) project has been proposed. SCENE aims to provide an advanced understanding of the intrinsic predictability of severe precipitation processes and the associated predictive ability of high-resolution meteorological models with a special focus on flash flood-producing storms in regions of complex orography (e.g. Mediterranean area) through the assessment of the role of both the convective and microphysical processes. The meteorological model considered in the project is the Weather Research and Forecasting (WRF) model, a state of the art mesoscale numerical weather prediction system designed to serve both operational forecasting and atmospheric research needs. Thus, among all the parameterizations available in the WRF model, the WRF Single-Moment 6-Class Scheme and the Thompson microphysics scheme will be adopted for the numerical simulations in combination with three different approaches for the treatment of the convective processes, that is the use of explicit method, Betts-Miller-Janjic Scheme and Kain-Fritsch. As for flash-flood producing storms, the project considers the recent sequence of extreme events occurred in the north-western portion of the Mediterranean sea; some of these events are the so-called critical cases of the DRIHM project (www.drihm.eu), i.e. selected severe

  12. High resolution simulations of extreme weather event in south Sardinia

    Science.gov (United States)

    Dessy, C.

    2010-05-01

    In the last decade, like most region of Mediterranean Europe, Sardinia has experienced severe precipitation events generating flash floods resulting in loss of lives and large economic damage. A numerical meteorological operational set-up is applied in the local weather service with the aim to improve the operational short range weather forecast of the Service with particular attention to intense, mostly rare and potentially severe, events. On the early hours of 22 October 2008 an intense and almost stationary mesoscale convective system interested particularly the south of Sardinia, heavy precipitation caused a flash flood with fatalities and numerous property damages. The event was particularly intense: about 400 mm of rain in 12 hours (a peak of 150 mm in an hour) were misured by the regional network of weather stations and these values appear extremely meaningfulls since those are about seven times the climatological monthly rainfall for that area and nearly the climatological annual rainfall. With the aim to improve significantly quantitative precipitation forecasting, it was evaluated a different set-up of a high resolution convection resolving model (MM5) initialised with different initial and boundary conditions (ECMWF and NCAR). In this paper it is discussed the meteorological system related to the mentioned event by using different numerical weather models (GCM and LAM) combined with conventional data, radar Doppler and Meteosat images. Preliminary results say that a different set-up of a non hydrostatic model can forecast severe convection events in advance of about one day and produce more realistic rainfall than that current operational and also improve the weather forecasts to respect the ECMWF-GCM. So it could drive an operational alert system in order to limit the risks associated with heavy precipitation events.

  13. 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.

  14. Assessing Hydrological Extreme Events with Geospatial Data and Models

    Science.gov (United States)

    Vivoni, Enrique R.; Grimaldi, Salvatore; Nardi, Fernando; Ivanov, Valeriy Y.; Castelli, Fabio; Bras, Rafael L.; Ubertini, Lucio

    2004-09-01

    Prediction of river basin hydrological response to extreme meteorological events is a primary concern in areas with frequent flooding, landslides, and debris flows. Natural hydrogeological disasters in many regions lead to extensive property damage, impact on societal activities, and loss of life. Hydrologists have a long history of assessing and predicting hydrologic hazards through the combined use of field observations, monitoring networks, remote sensing, and numerical modeling. Nevertheless, the integration of field data and computer models has yet to result in prediction systems that capture space-time interactions between meteorological forcing, land surface characteristics, and the internal hydrological response in river basins. Capabilities for assessing hydrologic extreme events are greatly enhanced via the use of geospatial data sets describing watershed properties such as topography, channel structure, soils, vegetation, and geological features. Recent advances in managing, processing, and visualizing cartographic data with geographic information systems (GIS) have enabled their direct use in spatially distributed hydrological models. In a distributed model application, geospatial data sets can be used to establish the model domain, specify boundary and initial conditions, determine the spatial variation of parameter values, and provide the spatial model forcing. By representing a watershed through a set of discrete elements, distributed models simulate water, energy, and mass transport in a landscape and provide estimates of the spatial pattern of hydrologic states, fluxes, and pathways.

  15. The Climatology of Taiwan extreme rainfall events and the attributions

    Science.gov (United States)

    Su, S. H.; Kuo, H. C.; Chen, Y. H.; Chu, J. L.; Lin, L. Y.

    2015-12-01

    Taiwan is located in the East-Asian monsoon region with average 2,500mm annual precipitation. Most significant Meteorological disasters are related to extreme precipitation which is associated with a complex terrain. Therefore, the long-term trends or climate variations in precipitation due to climate change are our major concern. We studied the climatology of extreme rainfall (ER, 95thpercentile) events in Taiwan using hourly precipitation data form 21 surface stations during 1960-2014. ER contributes about 40% of the total rain amount. It was found that approximately 68% of ER is related to typhoon (TY) and 22% associated with the Mei-Yu (MY) frontal system. The total ER amount annual variation is strongly related to TY, with correlation coefficient of 0.89 for rainfall amount and 0.86 for frequency. There is a significant increasing trend of TY-ER in past 55 years, but also has large variations over the annual and decadal time scales. The inter-annual variation of astounding extreme rainfall (AER, 99.9thpercentile) is increased significantly, especially in the past 15 years. It implies that the increasing of AER rainfall amount majorly caused by the increasing of frequency instead of average rain intensity of TY-AER. The MY-ER events are also highly correlated with the frontal system. The correlation is 0.84 for the rainfall amount and 0.83 of the frequency with the frontal days. There are also strong inter-annual variations of MY-ER, but the long-term trends are not as significant as TY-ER. The variation of frontal system number is another parameter may impact the MY-ER. The observational frontal system numbers had positive correlation with the MY-ER. The attribution of Taiwan TY-ER changes was debated in the research community. In general, the public acceptance of Taiwan extreme precipitation events is affected by multi-scale systems. According to observational data, the increasing of TY-ER amount is 37 % (48% )in Taiwan and some resent studies (Wang et al

  16. Distribution of extreme rainfall events over Ebro River basin

    Science.gov (United States)

    Saa, Antonio; Tarquis, Ana Maria; Valencia, Jose Luis; Gascó, Jose Maria

    2010-05-01

    The purpose of this work is to provide a description of the heavy rainfall phenomenon on statistical tools from a Spanish region. We want to quantify the effect of the climate change to verify the rapidity of its evolution across the variation of the probability distributions. Our conclusions have special interest for the agrarian insurances, which may make estimates of costs more realistically. In this work, the analysis mainly focuses on: The distribution of consecutive days without rain for each gauge stations and season. We estimate density Kernel functions and Generalized Pareto Distribution (GPD) for a network of station from the Ebro River basin until a threshold value u. We can establish a relation between distributional parameters and regional characteristics. Moreover we analyze especially the tail of the probability distribution. These tails are governed by law of power means that the number of events n can be expressed as the power of another quantity x : n(x) = x? . ? can be estimated as the slope of log-log plot the number of events and the size. The most convenient way to analyze n(x) is using the empirical probability distribution. Pr(X > x) ∞ x-?. The distribution of rainfall over percentile of order 0.95 from wet days at the seasonal scale and in a yearly scale with the same treatment of tails than in the previous section. The evolution of the distribution in the second XXth century and the impact on the extreme values model. After realized the analyses it does not appreciate difference in the distribution throughout the time which suggests that this region does not appreciate increase of the extreme values both for the number of dry consecutive days and for the value of the rainfall References: Coles, Stuart (2001). An Introduction to Statistical Modeling of Extreme Values,. Springer-Verlag Krishnamoorthy K. (2006), Handbook of Statistical Distributions with Applications, Chapman & Hall/CRC. Bodini A., Cossu A. (2010). Vulnerability assessment

  17. The 2010 Pakistan Flood and the Russia Heat Wave: Teleconnection of Extremes

    Science.gov (United States)

    Lau, William K.; Kim, K. M.

    2010-01-01

    The Pakistan flood and the Russia heat wave/Vvild fires of the summer of2010 were two of the most extreme, and catastrophic events in the histories of the two countries occurring at about the same time. To a casual observer, the timing may just be a random coincidence of nature, because the two events were separated by long distances, and represented opposite forces of nature, i.e., flood vs. drought, and water vs. fire. In this paper, using NASA satellite and NOAA reanalysis data, we presented observation evidences that that the two events were indeed physically connected.

  18. 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

  19. Warmer and wetter winters: characteristics and implications of an extreme weather event in the High Arctic

    Science.gov (United States)

    Hansen, Brage B.; Isaksen, Ketil; Benestad, Rasmus E.; Kohler, Jack; Pedersen, Åshild Ø.; Loe, Leif E.; Coulson, Stephen J.; Larsen, Jan Otto; Varpe, Øystein

    2014-11-01

    One predicted consequence of global warming is an increased frequency of extreme weather events, such as heat waves, droughts, or heavy rainfalls. In parts of the Arctic, extreme warm spells and heavy rain-on-snow (ROS) events in winter are already more frequent. How these weather events impact snow-pack and permafrost characteristics is rarely documented empirically, and the implications for wildlife and society are hence far from understood. Here we characterize and document the effects of an extreme warm spell and ROS event that occurred in High Arctic Svalbard in January-February 2012, during the polar night. In this normally cold semi-desert environment, we recorded above-zero temperatures (up to 7 °C) across the entire archipelago and record-breaking precipitation, with up to 98 mm rainfall in one day (return period of >500 years prior to this event) and 272 mm over the two-week long warm spell. These precipitation amounts are equivalent to 25 and 70% respectively of the mean annual total precipitation. The extreme event caused significant increase in permafrost temperatures down to at least 5 m depth, induced slush avalanches with resultant damage to infrastructure, and left a significant ground-ice cover (˜5-20 cm thick basal ice). The ground-ice not only affected inhabitants by closing roads and airports as well as reducing mobility and thereby tourism income, but it also led to high starvation-induced mortality in all monitored populations of the wild reindeer by blocking access to the winter food source. Based on empirical-statistical downscaling of global climate models run under the moderate RCP4.5 emission scenario, we predict strong future warming with average mid-winter temperatures even approaching 0 °C, suggesting increased frequency of ROS. This will have far-reaching implications for Arctic ecosystems and societies through the changes in snow-pack and permafrost properties.

  20. An agent-based approach to modelling the effects of extreme events on global food prices

    Science.gov (United States)

    Schewe, Jacob; Otto, Christian; Frieler, Katja

    2015-04-01

    Extreme climate events such as droughts or heat waves affect agricultural production in major food producing regions and therefore can influence the price of staple foods on the world market. There is evidence that recent dramatic spikes in grain prices were at least partly triggered by actual and/or expected supply shortages. The reaction of the market to supply changes is however highly nonlinear and depends on complex and interlinked processes such as warehousing, speculation, and export restrictions. Here we present for the first time an agent-based modelling framework that accounts, in simplified terms, for these processes and allows to estimate the reaction of world food prices to supply shocks on a short (monthly) timescale. We test the basic model using observed historical supply, demand, and price data of wheat as a major food grain. Further, we illustrate how the model can be used in conjunction with biophysical crop models to assess the effect of future changes in extreme event regimes on the volatility of food prices. In particular, the explicit representation of storage dynamics makes it possible to investigate the potentially nonlinear interaction between simultaneous extreme events in different food producing regions, or between several consecutive events in the same region, which may both occur more frequently under future global warming.

  1. Modern sedimentation and extreme event in the South China Sea

    Science.gov (United States)

    Chen, Yu-Huang; Su, Chih-Chieh

    2016-04-01

    The South China Sea is the largest marginal sea of the northwest Pacific. It is situated at the plate boundary of the Eurasian, Philippine Sea, and Indian plates and also on the North Western Pacific corridor of typhoons. The unique tectonic and climatic environment makes it has to face the potential of seafloor destructions, like submarine landslides and slumps, and high sediment discharges which induced by typhoon from Philippine. In this study, we analysis the sediment properties of modern extreme event records in cores and attempt to evaluate the history of extreme events in the South China Sea. Twelve gravity cores were collected in the central South China Sea basin and around Taiping island by using R/V Ocean Research 1 from 2014 to 2015 and a series of analysis including multi-sensor core logger, XRF core scanner (Itrax), core surface images, X-radiographs, bulk density, grain size, Pb-210 chronology and X-ray diffractometer were conducted in this study. On core surface images, an obvious brownish oxidized layer exist in core top with higher Pb-210 activity beneath this oxidized layer, and we speculate this layer is caused by nature hazard. According to the sampling time, we conjecture the oxidized layer might formed by typhoon Haiyan in 2013. In addition, the Itrax data shows high manganese content only exist in this layer which might related to the modern industrial pollution delivered by typhoon induced flooding from Philippine. The sedimentation rate of the non-event years in these cores which derived from Pb-210 chronology method is about 0.02 ~0.03 cm/yr. On contrary, the event layer caused by Haiyan with a recorded maximum 87cm deposits in the South China Sea. This study aims to characterize the typhoon induced deposits in the turbidite layer and use it to identify whether the other event layers recorded in these cores were related to typhoon activities and to reconstruct the strong tropical cyclone history in the western Pacific.

  2. Multi-wavelength Analysis to Solar Corona Heating Events

    Science.gov (United States)

    Yang, Xu; Ji, Hai-sheng; Li, Hao-Chuan

    2015-01-01

    With the advent and successful operation of the 1.6 m aperture New Solar Telescope of Big Bear Solar Observatory (BBSO/NST), solar observation has entered the era of high resolution better than 0.1". This permits us to carry out the case studies of single coronal heating events, to provide the original high-resolution observational evidence for finally solving the problem of coronal heating. By combining the high-resolution Helium I 10830 Å, TiO 7057 Å, and Ha blue-wing (-0.7 Å) imaging data from the NST with the imaging data of extreme ultraviolet and longitudinal magnetic field observed simultaneously by the Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) on board of the Solar Dynamics Observatory (SDO), we have analyzed the evolution of magnetic field in two tiny dynamical events of coronal heating (brightening of magnetic loops) that originate from the solar intergranular lanes. It is found that the footpoints of both brightening magnetic loops were all located in the one side of nearby neutral line of magnetic fields, the footpoints of one magnetic loop were accompanied by the disappearance of a small longitudinal magnetic element and the newly formed connection between two granulations, while the footpoints of another magnetic loop were accompanied by a weak variation of longitudinal magnetic field and the breakdown of a granulation. The observed result tends to suggest that the low-temperature and high-temperature outflows were produced simultaneously by the magnetic reconnection occurred among the solar granulations in the low-layer atmosphere. Meanwhile, it is noted that the high-resolution and high-accuracy polarization measurement of photospheric magnetic field is crucial for finally solving the problem of coronal heating.

  3. Extreme fog events in Poland with respect to circulation conditions

    Science.gov (United States)

    Ustrnul, Z.; Czekierda, D.; Wypych, A.

    2010-09-01

    Fog is a phenomenon which belongs to a group of so-called hydrometeorites and, according to the different dictionaries, it is a suspension of water droplets or ice crystals in the ground layer of the air that impairs visibility in the horizontal direction below 1 km. The phenomenon of fog, although much less dynamic or violent than other extreme phenomena, such as thunderstorms or hail, is equally dangerous and brings about huge social and economic complications. Land and air transportation suffer and fog may sometimes leads to a complete crippling of the whole economy in an area where fog occurs. The main objective of the study is determination of the circulation types bringing extreme fog events in Poland. The duration of fog at each meteorological station was considered as the main input data originated from 54 synoptic stations located across the country. The mentioned data series cover the period of 56 years (1951-2006). The occurrence of fog depends on meteorological conditions caused to a large extent by a given synoptic situation and local terrain conditions. In this study, according to its objectives, only circulation conditions are taken into consideration. These have been described by 5 different circulation classifications (Grosswetterlagen, Litynski, Osuchowska-Klein, Niedzwiedz and Ustrnul). Situations when this phenomenon occurred across a large part of the country were taken into detailed consideration. Special attention was paid to fog coverage during 24-hour periods. In this work, in light of certain doubts about the homogeneity of the observation material available, the intensity of fog was not included, as it requires additional and very tedious analysis. In the first step all cases of fog during the 1966-2006 study period which lasted 24 hours at more than 10 of the considered weather stations, i.e: at least 5 stations have been considered. As expected, in most cases, either a centre of a classical high pressure system or a high pressure wedge

  4. A mechanism for decadal variations in the frequency of extreme El Niño events

    Science.gov (United States)

    Wang, G.; Cai, W.

    2015-12-01

    The El Niño Southern Oscillation (ENSO), the largest source of Earth's climate variability on interannual time scales, has massive impacts on extreme weathers, agriculture and ecosystems, particularly during extreme El Niño events, such as the 1982/83 and 1997/98 episodes. However, the associated mechanism is not fully understood, hindering their forecasts, as attested by the false alarm of an extreme El Niño in 2014 predicted by many models. Recent studies have identified additional precursors beyond westerly wind anomalies and oceanic heat content along the equatorial Pacific, including the southwest Pacific southerly jets, which tend to occur strongly and concurrently with equatorial westerly anomalies during extreme El Niño, but NOT during weak El Niño events. Here we show that the concurrences of southwest Pacific southerlies, anomalous equatorial westerlies, and their relationship, are modulated by the Pacific Decadal Oscillation (PDO)/Interdecadal Pacific Oscillation (IPO), even on daily timescales. During a positive phase of the PDO/IPO, occurrences of westerly wind events (WWEs), in the region between the Maritime continent and the eastern Pacific Ocean, are reinforced by the southwest Pacific southerly surges (SPSSs) in austral winter. By contrast, during a negative phase of the PDO/IPO, such SPSSs are not reinforcing WWEs; instead stronger SPSSs are associated with weaker WWEs. This interdecadal contrast in the relationship between SPSSs and WWEs contributes to the decadal variations in the frequency of extreme El Niño events. The associated mechanism will be discussed.

  5. Impacts of extreme winter warming events on plant physiology in a sub-Arctic heath community.

    Science.gov (United States)

    Bokhorst, Stef; Bjerke, Jarle W; Davey, Matthew P; Taulavuori, Kari; Taulavuori, Erja; Laine, Kari; Callaghan, Terry V; Phoenix, Gareth K

    2010-10-01

    Insulation provided by snow cover and tolerance of freezing by physiological acclimation allows Arctic plants to survive cold winter temperatures. However, both the protection mechanisms may be lost with winter climate change, especially during extreme winter warming events where loss of snow cover from snow melt results in exposure of plants to warm temperatures and then returning extreme cold in the absence of insulating snow. These events cause considerable damage to Arctic plants, but physiological responses behind such damage remain unknown. Here, we report simulations of extreme winter warming events using infrared heating lamps and soil warming cables in a sub-Arctic heathland. During these events, we measured maximum quantum yield of photosystem II (PSII), photosynthesis, respiration, bud swelling and associated bud carbohydrate changes and lipid peroxidation to identify physiological responses during and after the winter warming events in three dwarf shrub species: Empetrum hermaphroditum, Vaccinium vitis-idaea and Vaccinium myrtillus. Winter warming increased maximum quantum yield of PSII, and photosynthesis was initiated for E. hermaphroditum and V. vitis-idaea. Bud swelling, bud carbohydrate decreases and lipid peroxidation were largest for E. hermaphroditum, whereas V. myrtillus and V. vitis-idaea showed no or less strong responses. Increased physiological activity and bud swelling suggest that sub-Arctic plants can initiate spring-like development in response to a short winter warming event. Lipid peroxidation suggests that plants experience increased winter stress. The observed differences between species in physiological responses are broadly consistent with interspecific differences in damage seen in previous studies, with E. hermaphroditum and V. myrtillus tending to be most sensitive. This suggests that initiation of spring-like development may be a major driver in the damage caused by winter warming events that are predicted to become more

  6. Increased Stream Temperature in Response to Extreme Precipitation Events

    Science.gov (United States)

    Wilson, C. E.; Gooseff, M. N.

    2016-12-01

    Aquatic ecosystem temperature regulation is essential to the survival of riverine fish species restricted to limited water temperature ranges. Dissolved oxygen levels, similarly necessary to fish health, are decreased by rising temperatures, as warmer waters can hold less oxygen than colder waters. Climate change projections forecast increased precipitation intensities, a trend that has already been observed in the past decade. Though extreme events are becoming more common, the stream temperature response to high-intensity rainfall is not yet completely understood. Precipitation and stream temperature records from gages in the Upper Midwestern United States were analyzed to determine whether there exists a positive relationship between high-intensity rainfall and stream temperature response. This region was chosen for its already observed trends in increasing precipitation intensity, and rural gages were used in order to minimize the effect of impervious surfaces on runoff amounts and temperature. Days with recorded precipitation were divided by an intensity threshold and classified as either high-intensity or low-intensity days. While the effects of rain events on temperature are variable, increases in stream temperature in response to high-intensity rainfall were observed. For some basins, daily maximum rates of stream temperature increase were, on average, greater for higher intensity events. Similarly, the average daily stream temperature range was higher in streams on days of high-intensity precipitation, compared to days of low-intensity events. Understanding the effect of increasing precipitation intensity in conjunction with rising air temperatures will provide insight into the future of aquatic ecosystems and their adaptation to climate change.

  7. Management of the Extreme Events: Countering International Terrorism

    Directory of Open Access Journals (Sweden)

    Dr. Cristian Barna

    2011-12-01

    Full Text Available After the terrorism attacks of September 11, 2001, there is recognition by both the public and private sectors that one needs to rethink our strategy for dealing with these low probability but extreme consequence events. September 11, 2001 attacks against the United States raised numerous questions related to counter-terrorism, foreign policy, as well as national security in the United States and abroad. They also raised the fundamental question of who should pay for losses due to terrorism.The question of who should pay for terrorism risk prevention and sustainable coverage within a country is likely to be seen first as a matter of collective responsibility that each country has to consider – a societal choice

  8. Changes of extreme drought and flood events in Iran

    Science.gov (United States)

    Modarres, Reza; Sarhadi, Ali; Burn, Donald H.

    2016-09-01

    Located in an arid and semi-arid region of the world, Iran has experienced many extreme flood and drought events in the last and current century. The present study aims to assess the changes in Iran's flood magnitude and drought severity for 1950-2010, with some time span variation in some stations. The Mann-Kendall test for monotonic trend was first applied to assess changes in flood and drought severity data. In addition, to consider the effect of serial correlation, two Pre-Whitening Trend (PWT) tests were also applied. It was observed that the number of stations with statistically significant trends has increased after applying PWT tests. Both increasing and decreasing trends were observed for drought severity and flood magnitude in different climate regions and major basins of Iran using these tests. The increase in flood magnitude and drought severity can be attributed partly to land use changes, an annual rainfall negative trend, a maximum rainfall increasing trend, and inappropriate water resources management policies. The paper indicates a critical situation related to extreme climate change in Iran and the increasing risk of environmental changes in the 21st century.

  9. 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.

  10. Extreme events of 2012, 2013 and 2014 linked to planetary wave resonance

    Science.gov (United States)

    Petoukhov, Vladimir; Coumou, Dim; Rahmstorf, Stefan; Stadtherr, Lisa; Kornhuber, Kai; Petri, Stefan; Schellnhuber, Hans Joachim

    2016-04-01

    Quasi-stationary planetary waves of large-amplitude have been linked to the occurrence of many of the most extreme weather events of the past decades in the Northern Hemisphere. This includes the European heat waves of 2003 and 2010 as well as the catastrophic Elbe flooding 2002. A resonance mechanism was proposed to explain the occurrence of large-amplitude planetary waves (Petoukhov et al. 2013) and a recent increase in the frequency of resonance events has been identified (Coumou et al. 2014). We extend the analysis to more recent extreme weather events. 2012 marked the warmest spring on record in the USA, accompanied by wettest spring in 100 years in the UK and national heat records for the warmest temperature in spring in 13 other European countries; torrential rains and demolishing floods in central and eastern China together with an oppressive heat wave in the USA in June; hottest July on record in the USA simultaneously with the worst flooding in 60 years in eastern China and Japan; unparalleled heat in the USA and destructive floods in China and the Philippines in August; and widespread floods in the UK in September. 2013 saw Central European Flooding in May-early June; trains of persistent heat waves in the USA and China in mid-June; and in the USA, central Europe, and western and eastern China end of June/July; strong floods in central China and Japan in late July/early August; and in north-eastern China and eastern Russia in mid-and late August; a sweltering heat wave in eastern China and Japan in early September; the worst flood in central China in late September/early October. The obtained results confirm a recent tendency to an increase in the frequency of occurrence of quasi-resonant conditions, favoring the emergence of persistent regional extremes in the NH mid-latitudes (Petoukhov et al, submitted). In May 2014, the Balkans were hit by a Vb-type cyclone that brought disastrous flooding and severe damage to Bosnia and Herzegovina, Serbia and

  11. Generating extreme weather event sets from very large ensembles of regional climate models

    Science.gov (United States)

    Massey, Neil; Guillod, Benoit; Otto, Friederike; Allen, Myles; Jones, Richard; Hall, Jim

    2015-04-01

    range of SST responses, as well as a range of RCP scenarios, allows us to assess the uncertainty in the response to elevated GHG emissions that occurs in the CMIP5 ensemble. Numerous extreme weather events can be studied. Firstly, we analyse droughts in Europe with a focus on the UK in the context of the project MaRIUS (Managing the Risks, Impacts and Uncertainties of droughts and water Scarcity). We analyse the characteristics of the simulated droughts, the underlying physical mechanisms, and assess droughts observed in the recent past. Secondly, we analyse windstorms by applying an objective storm-identification and tracking algorithm to the ensemble output, isolating those storms that cause high loss and building a probabilistic storm catalogue, which can be used by impact modellers, insurance loss modellers, etc. Finally, we combine the model output with a heat-stress index to determine the detrimental effect on health of heat waves in Europe. [1] Massey, N. et al., 2014, Q. J. R. Meteorol. Soc.

  12. Interpreting Climate Model Projections of Extreme Weather Events for Decision Makers

    Science.gov (United States)

    Vavrus, S. J.; Notaro, M.

    2014-12-01

    The proliferation of output from climate model ensembles, such as CMIP3 and CMIP5, has greatly expanded access to future projections, but there is no accepted blueprint for how this data should be interpreted. Decision makers are thus faced with difficult questions when trying to utilize such information: How reliable are the multi-model mean projections? How should the changes simulated by outlier models be treated? How can raw projections of temperature and precipitation be translated into probabilities? The multi-model average is often regarded as the most accurate single estimate of future conditions, but higher-order moments representing the variance and skewness of the distribution of projections provide important information about uncertainty. We have analyzed a set of statistically downscaled climate model projections from the CMIP3 archive to conduct an assessment of extreme weather events at a level designed to be relevant for decision makers. Our analysis uses the distribution of 13 GCM projections to derive the inter-model standard deviation (and coefficient of variation, COV), skewness, and percentile ranges for simulated changes in extreme heat, cold, and precipitation during the middle and late 21st century for the A1B emissions scenario. These metrics help to establish the overall confidence level across the entire range of projections (via the inter-model COV), relative confidence in the simulated high-end versus low-end changes (via skewness), and probabilistic uncertainty bounds derived from a bootstrapping technique. Over our analysis domain centered on the United States Midwest, some primary findings include: (1) Greater confidence in projections of less extreme cold than more extreme heat and intense precipitation, (2) Greater confidence in the low-end than high-end projections of extreme heat, and (3) Higher spatial and temporal variability in the confidence of projected increases of heavy precipitation. In addition, our bootstrapping

  13. 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

  14. Evaluation of extreme temperature events in northern Spain based on process control charts

    Science.gov (United States)

    Villeta, M.; Valencia, J. L.; Saá, A.; Tarquis, A. M.

    2017-02-01

    Extreme climate events have recently attracted the attention of a growing number of researchers because these events impose a large cost on agriculture and associated insurance planning. This study focuses on extreme temperature events and proposes a new method for their evaluation based on statistical process control tools, which are unusual in climate studies. A series of minimum and maximum daily temperatures for 12 geographical areas of a Spanish region between 1931 and 2009 were evaluated by applying statistical process control charts to statistically test whether evidence existed for an increase or a decrease of extreme temperature events. Specification limits were determined for each geographical area and used to define four types of extreme anomalies: lower and upper extremes for the minimum and maximum anomalies. A new binomial Markov extended process that considers the autocorrelation between extreme temperature events was generated for each geographical area and extreme anomaly type to establish the attribute control charts for the annual fraction of extreme days and to monitor the occurrence of annual extreme days. This method was used to assess the significance of changes and trends of extreme temperature events in the analysed region. The results demonstrate the effectiveness of an attribute control chart for evaluating extreme temperature events. For example, the evaluation of extreme maximum temperature events using the proposed statistical process control charts was consistent with the evidence of an increase in maximum temperatures during the last decades of the last century.

  15. Observations and Impact Assessments of Extreme Space Weather Events

    Science.gov (United States)

    Baker, D. N.

    2007-05-01

    "Space weather" refers to conditions on the Sun, in the solar wind, and in Earth`s magnetosphere, ionosphere, and thermosphere. Activity on the Sun such as solar flares and coronal mass ejections can lead to high levels of radiation in space and can cause major magnetic storms at the Earth. Space radiation can come as energetic particles or as electromagnetic emissions. Adverse conditions in the near-Earth space environment can cause disruption of satellite operations, communications, navigation, and electric power distribution grids. This can lead to a variety of socioeconomic losses. Astronauts and airline passengers exposed to high levels of radiation are also at risk. Society`s vulnerability to space weather effects is an issue of increasing concern. We are dependent on technological systems that are becoming more susceptible to space weather disturbances. We also have a permanent human presence in space with the International Space Station and the President and NASA have expressed a desire to expand our human space activities with missions to the moon and Mars. This will make space weather of even greater concern in the future. In this talk I will describe many space weather effects and will describe some of the societal and economic impacts that extreme events have had.

  16. The effect of myostatin genotype on body temperature during extreme temperature events.

    Science.gov (United States)

    Howard, J T; Kachman, S D; Nielsen, M K; Mader, T L; Spangler, M L

    2013-07-01

    Extreme heat and cold events can create deleterious physiological changes in cattle as they attempt to cope. The genetic background of animals can influence their response to these events. The objective of the current study was to determine the impact of myostatin genotype (MG) on body temperature during periods of heat and cold stress. Two groups of crossbred steers and heifers of unknown pedigree and breed fraction with varying percentages of Angus, Simmental, and Piedmontese were placed in a feedlot over 2 summers and 2 winters. Before arrival, animals were genotyped for the Piedmontese-derived myostatin mutation (C313Y) to determine their MG as either homozygous normal (0 copy; n = 84), heterozygous (1 copy; n = 96), or homozygous for inactive myostatin (2 copy; n = 59). Hourly tympanic and vaginal temperature measurements were collected for steers and heifers, respectively, for 5 d during times of anticipated heat and cold stress. Mean (±SD) ambient temperature for summer and winter stress events were 24.4 (±4.64) and -1.80 (±11.71), respectively. A trigonometric function (sine + cosine) with periods of 12 and 24 h was used to describe the diurnal cyclical pattern. Hourly body temperature was analyzed within a season, and fixed effects included MG, group, trigonometric functions nested within group, and interaction of MG with trigonometric functions nested within group; random effects were animal and residual (Model [I]). A combined analysis of season and group was also investigated with the inclusion of season as a main effect and the nesting of effects within both group and season (Model [C]). In both models, the residual was fitted using an autoregressive covariance structure. A 3-way interaction of MG, season, and trigonometric function periodicities of 24 h (P 0.05). The current study illustrated that a genotype × environment interaction exists for MG and 1-copy animals were more robust to environmental extremes in comparison with 0- or 2-copy animals.

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

    Science.gov (United States)

    Serykh, Ilya; Kostianoy, Andrey

    2016-04-01

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

  18. 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

  19. Attribution of extreme events in the western US to human activities

    Science.gov (United States)

    Mera, R. J.

    2015-12-01

    A project to investigate the role of human activities on the changing nature of extreme events in the western US began as part of a CLIVAR-sponsored Postdocs Applying Climate Expertise (PACE) project. The climate institution was the Oregon State University and the application partner was the Oregon Department of Land Conservation and Development (DLCD). DLCD was interested in the changes in weather extremes in the Pacific Northwest, specifically extreme rainfall, flooding, and droughts. The project employs very large ensembles of regional model simulations through volunteer computing resources and allows for probabilistic event attribution (PEA), an important climate research technique. The model was found to have good representation of atmospheric rivers, a major source of extreme precipitation in the Pacific Northwest. The model domain also encompasses California and Nevada. One of the studies focused on attribution of extreme heat in relation to vulnerable populations in California's Central Valley, where heat waves have become progressively more severe due to increasing nighttime temperatures. Specifically, we found that that (1) simulations of the hottest summer days during the 2000s were twice as likely to occur using observed levels of greenhouse gases than in a counterfactual world without major human activities, (2) detrimental impacts of heat on public health-relevant variables, such as the number of days above 40°C, can be quantified and attributed to human activities using PEA, and (3) PEA can serve as a tool for addressing climate justice concerns of populations within developed nations. The research conducted through the PACE program has also provided a framework for a pioneering climate attribution study at the Union of Concerned Scientists (UCS). The UCS project takes advantage of new research that shows that nearly two-thirds of carbon pollution released into the atmosphere, reported as carbon dioxide equivalent with hundred-year global warming

  20. Role of Anomalous States of Upper Tropospheric Circulation on Extremely Dry and Wet Summer Monsoon Events

    Science.gov (United States)

    Ahmad, S.; Koike, T.; Nishii, K.; Shrestha, M.

    2011-12-01

    Seasonal changes in wind pattern, monsoon, sometimes result in severe droughts and intense flooding in many parts of the world including South Asian countries like Pakistan. The livelihood of a vast population in Pakistan depends on agriculture and land use is strongly influenced by water-based ecosystems that depend on the monsoon rains. Furthermore, climate change studies undertaken so far reveal that action is essential in order to prevent long term damage to water cycle and thus of great concern to the community and stakeholders. Pakistan Summer Monsoon (PSM) is affected by both the disturbances from the tropical and the extratropical regions; however there is lack of understanding of physical mechanisms of PSM compared to other regional studies i.e. Indian Summer Monsoon (ISM) and South-East Asian Monsoon (SEAM). In our study, we applied heat and vorticity budgets, and wave train analysis to reveal the mechanisms of the extremely dry and wet PSM events associated with the anomalous upper tropospheric conditions. We found that the extremely dry (wet) PSM events were closely related with the anomalous cyclonic (anticyclonic) upper-tropospheric circulation around northwest of Pakistan, and mid-upper tropospheric cooling (warming) anomaly around Pakistan and to its north/northwest. We also found in addition to Rossby wave response due to the suppressed (enhanced) convective activities around monsoon regions, the midlatitude wave energy propagation emanating around cyclonic/anticyclonic anomaly around northwestern Atlantic, northeastern Atlantic, Europe or Mediterranean regions induced/reinforced/maintained the anomalous upper tropospheric cyclonic (anticyclonic) circulation around northwest of Pakistan during extremely dry (wet) PSM events. Therefore, devastating drought (flood) events over the PSM region resulting from weak (strong) convection anomalies are induced by both the tropical and extratropical processes.

  1. Atmospheric rivers and cool season extreme precipitation events in Arizona

    Science.gov (United States)

    Rivera Fernandez, Erick Reinaldo

    Atmospheric rivers (ARs) are important contributors to cool season precipitation in the Southwestern US, and in some cases can lead to extreme hydrometeorological events in the region. We performed a climatological analysis and identified two predominant types of ARs that affect the central mountainous region in Arizona: Type 1 ARs originate in the tropics near Hawaii (central Pacific) and enhance their moisture in the midlatitudes, with maximum moisture transport over the ocean at low-levels of the troposphere. On the other hand, moisture in Type 2 ARs has a more direct tropical origin and meridional orientation with maximum moisture transfer at mid-levels. We then analyze future projections of Southwest ARs in a suite of global and regional climate models used in the North American Regional Climate Change Assessment Program (NARCCAP), to evaluate projected future changes in the frequency and intensity of ARs under warmer global climate conditions. We find a consistent and clear intensification of the water vapor transport associated with the ARs that impinge upon Arizona and adjacent regions, however, the response of AR-related precipitation intensity to increased moisture flux and column-integrated water vapor is weak and no robust variations are projected either by the global or the regional NARCCAP models. To evaluate the effect of horizontal resolution and improve our physical understanding of these results, we numerically simulated a historical AR event using the Weather Research and Forecasting (WRF) model at a 3-km resolution. We then performed a pseudo-global warming experiment by modifying the lateral and lower boundary conditions to reflect possible changes in future ARs (as projected by the ensemble of global model simulations used for NARCCAP). Interestingly we find that despite higher specific humidity, some regions still receive less rainfall in the warming climate experiments - partially due to changes in thermodynamics, but primarily due to AR

  2. The Relation between Extreme Weather Events and the Solar Activity

    Science.gov (United States)

    Battinelli, P.; di Fazio, A.; Torelli, M.

    The oscillating part of the solar irradiance drives the cyclic component of the variations of the terrestrial atmosphere's thermodynamic state. In particular, the average temperature, and thus the turbulent atmospheric fuxes, are influenced. Reliable temperature data exist from ~220,000 years, while accurate solar irradiance space measurements (not affected by the atmosphere's absorption) are available only since 1979. Actually, there is a rather long data-set regarding solar activity, indicated by the Wolf number, which is found to be well correlated with the total solar flux. Thus, we use the Wolf number as a quantitative proxy of the incident flux, even in the interval before the space-based measurements. The fraction of solar energy trapped in the atmosphere due to the re-absorption of the infrared radiation by the greenhouse gases is an increasing function of time (in the latter 150-160 years). Over this interval, we spectrally analyzed the time series of both the Wolf number and the frequencies of extreme meteorological events, isolating and removing in the latter the cyclic components due to the periodic part of the radiative forcing exherted by the Sun. We were thus able to determine the time trend in the data regarding the observed frequencies of the U.S. continental tornadoes (National Center for Atmospheric Research) and of the global cyclones (hurricanes and tropical storms on all ocean basins, National Ocean and Atmospheric Administration). We find, for both the data sets an exponential behaviour, with e-folding times: for the cyclones tau ~= 110 years, and for the tornadoes tau ~= 70 years. We are happy to have given --through this work-- a contribution to the interdisciplinary scientific process coordinated by the IPCC (Intergovernmental Panel on Climate Change) through the ICSU (International Council of Scientific Unions) which takes place a latere of the international negotiations under the United Nations Framework Convention on Climate Change.

  3. The XIV Global Warming International Conference & Expo (GWXIV)——Global extreme events

    Institute of Scientific and Technical Information of China (English)

    JamesA.Roberts

    2004-01-01

    The focus of this year's conference is Global Extreme Events, characterized as large-scale climatic effects that have been increasing in magnitude and frequency. Prof. Sinyan Shen, Chairman of the GW International Program Committee, has been leading the world on Global Extreme Events and Emergency Response. In the long term climate change will cause the Earth to transit to another equilibrium state through many oscillations in climatic pattern. Global warming causes extreme events and bad weather in the near term. The immediate

  4. 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.

  5. Temporal Changes in Extreme High Temerature, Heat Waves in Istanbul Between 1960-2014

    Science.gov (United States)

    Yürük, C.; Ünal, Y. S.; Bilgen, S. I.; Menteş, Ş. S.; İncecik, S.

    2015-12-01

    Climate change has crucial effects on cities and especially for informal settlements, urban poor and other vulnerable groups by influencing human health, assets and livelihoods. These impacts directly result from the variations in temperature and precipitation, and emergence of heat waves, droughts, floods and fires (IPCC, 2014). Summertime episodes with extremely high air temperatures which last for several days or longer are addressed to as heat waves and affect the weather and climate in the globe. The aim of this study is to analyze the occurrence of heat waves in terms of quantity, duration and frequency and also to evaluate the accuracy of the COSMO-CLM (CCLM) model in reproducing the characteristics of heat waves in Istanbul. The summer maximum temperatures of six Turkish State Meteorological Service (TSMS) stations are selected between 1960 and 2014 to estimate the characteristics of heat waves in Istanbul. We define the heat wave if the maximum temperatures exceed a threshold value for at least three consecutive days. The threshold value is determined as 30.5 from the 90th percentile of all six station's observations. Then it is used in the detection of the hot days, heat waves and their durations. The results show that not only the number of heat waves but also duration of heat waves increase towards the end of the study period. Especially, a significant increase in heat wave events is evident after 1990s. In 2012, the number of hot days reaches the maximum value in all stations and Kartal station located southern part of city, has the highest value of 60 hot days. Furthermore, Kartal as an urban area in the Asian side of the city, exhibits highest heat wave duration with 18 consecutive days in 1998. To estimate the relationship between urban heat island intensity and the heat waves, we examined data at 43 stations collected by Disaster Coordination Center and TSMS between 2007 and 2012. Urban heat island phenomenon is found to be related to higher

  6. Representing Extreme Temperature Events and Resolving Their Implications for Yield

    Science.gov (United States)

    Huybers, P. J.; Mueller, N. D.; Butler, E. E.; Tingley, M.; McKinnon, K. A.; Rhines, A. N.

    2014-12-01

    Although it is well recognized that extreme temperatures occurring at particular growth stages are destructive to yield, there appears substantial scope for improved empirical assessment and simulation of the relationship between temperature and yield. Several anecdotes are discussed. First, a statistical analysis of historical U.S. extreme temperatures is provided. It is demonstrated that both reanalysis and model simulations significantly differ from near-surface temperature observations in the frequency and magnitude of extremes. This finding supports empirical assessment using near-surface instrumental records and underscores present difficulties in simulating past and predicting future changes. Second, an analysis of the implications of extreme temperatures on U.S. maize yield is provided where the response is resolved regionally and according to growth stage. Sensitivity to extreme temperatures during silking is found to be uniformly high across the U.S., but the response during grain filling varies spatially, with higher sensitivity in the North. This regional and growth-stage dependent sensitivity implies the importance of representing cultivar, planting times, and development rates, and is also indicative of the potential for future changes according to the combined effects of climate and technology. Finally, interaction between extreme temperatures and agriculture is indicated by analysis showing that historical extreme temperatures in the U.S. Midwest have cooled in relation to changes in regional productivity, possibly because of greater potential for cooling through evapotranspiration. This interpretation is consistent with changes in crop physiology and management, though also noteworthy is that the moderating influence of increased evapotranspiration on extreme temperatures appears to be lost during severe drought. Together, these findings indicate that a more accurate assessment of the historical relationship between extreme temperatures and yield

  7. An Urban Resilience to Extreme Weather Events Framework for Development of Post Event Learning and Transformative Adaptation in Cities

    Science.gov (United States)

    Solecki, W. D.; Friedman, E. S.; Breitzer, R.

    2016-12-01

    Increasingly frequent extreme weather events are becoming an immediate priority for urban coastal practitioners and stakeholders, adding complexity to decisions concerning risk management for short-term action and long-term needs of city climate stakeholders. The conflict between the prioritization of short versus long-term events by decision-makers creates disconnect between climate science and its applications. The Consortium for Climate Risk in the Urban Northeast (CCRUN), a NOAA RISA team, is developing a set of mechanisms to help bridge this gap. The mechanisms are designed to promote the application of climate science on extreme weather events and their aftermath. It is in the post event policy window where significant opportunities for science-policy linkages exist. In particular, CCRUN is interested in producing actionable and useful information for city managers to use in decision-making processes surrounding extreme weather events and climate change. These processes include a sector specific needs assessment survey instrument and two tools for urban coastal practitioners and stakeholders. The tools focus on post event learning and connections between resilience and transformative adaptation. Elements of the two tools are presented. Post extreme event learning supports urban coastal practitioners and decision-makers concerned about maximizing opportunities for knowledge transfer and assimilation, and policy initiation and development following an extreme weather event. For the urban U.S. Northeast, post event learning helps coastal stakeholders build the capacity to adapt to extreme weather events, and inform and develop their planning capacity through analysis of past actions and steps taken in response to Hurricane Sandy. Connecting resilience with transformative adaptation is intended to promote resilience in urban Northeast coastal settings to the long-term negative consequences of extreme weather events. This is done through a knowledge co

  8. The 2010 Pakistan Flood and Russian Heat Wave: Teleconnection of Hydrometeorological Extremes

    Science.gov (United States)

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

    2012-01-01

    In this paper, preliminary results are presented showing that the two record-setting extreme events during 2010 summer (i.e., the Russian heat wave-wildfires and Pakistan flood) were physically connected. It is found that the Russian heat wave was associated with the development of an extraordinarily strong and prolonged extratropical atmospheric blocking event in association with the excitation of a large-scale atmospheric Rossby wave train spanning western Russia, Kazakhstan, and the northwestern China-Tibetan Plateau region. The southward penetration of upper-level vorticity perturbations in the leading trough of the Rossby wave was instrumental in triggering anomalously heavy rain events over northern Pakistan and vicinity in mid- to late July. Also shown are evidences that the Russian heat wave was amplified by a positive feedback through changes in surface energy fluxes between the atmospheric blocking pattern and an underlying extensive land region with below-normal soil moisture. The Pakistan heavy rain events were amplified and sustained by strong anomalous southeasterly flow along the Himalayan foothills and abundant moisture transport from the Bay of Bengal in connection with the northward propagation of the monsoonal intraseasonal oscillation.

  9. Data-driven prediction and prevention of extreme events in a spatially extended excitable system.

    Science.gov (United States)

    Bialonski, Stephan; Ansmann, Gerrit; Kantz, Holger

    2015-10-01

    Extreme events occur in many spatially extended dynamical systems, often devastatingly affecting human life, which makes their reliable prediction and efficient prevention highly desirable. We study the prediction and prevention of extreme events in a spatially extended system, a system of coupled FitzHugh-Nagumo units, in which extreme events occur in a spatially and temporally irregular way. Mimicking typical constraints faced in field studies, we assume not to know the governing equations of motion and to be able to observe only a subset of all phase-space variables for a limited period of time. Based on reconstructing the local dynamics from data and despite being challenged by the rareness of events, we are able to predict extreme events remarkably well. With small, rare, and spatiotemporally localized perturbations which are guided by our predictions, we are able to completely suppress extreme events in this system.

  10. Extreme climatic events: impacts of drought and high temperature on physiological processes in agronomically important plants

    Directory of Open Access Journals (Sweden)

    Urs eFeller

    2014-10-01

    Full Text Available Climate models predict more frequent and more severe extreme events (e.g. heat waves, extended drought periods, flooding in many regions for the next decades. The impact of adverse environmental conditions on crop plants is ecologically and economically relevant. This review is focused on drought and heat effects on physiological status and productivity of agronomically important plants. Stomatal opening represents an important regulatory mechanism during drought and heat stress since it influences simultaneously water loss via transpiration and CO2 diffusion into the leaf apoplast which further is utilized in photosynthesis. Along with the reversible short-term control of stomatal opening, stomata and leaf epidermis may produce waxy deposits and irreversibly down-regulate the stomatal conductance and non-stomatal transpiration. As a consequence photosynthesis will be negatively affected. Rubisco activase - a key enzyme in keeping the Calvin cycle functional – is heat-sensitive and may become a limiting factor at elevated temperature. The accumulated reactive oxygen species during stress represent an additional challenge under unfavorable conditions. Drought and heat cause accumulation of free amino acids which are partially converted into compatible solutes such as proline. This is accompanied by lower rates of both nitrate reduction and de novo amino acid biosynthesis. Protective proteins (e.g. dehydrins, chaperones, antioxidant enzymes or the key enzyme for proline biosynthesis play an important role in leaves and may be present at higher levels under water deprivation or high temperatures. On the whole plant level, effects on long-distance translocation of solutes via xylem and phloem and on leaf senescence (e.g. anticipated, accelerated or delayed senescence are important. The factors mentioned above are relevant for the overall performance of crops under drought and heat and must be considered for genotype selection and breeding programs.

  11. Climate Model Simulation of Present and Future Extreme Events in Latin America and the Caribbean: What Spatial Resolution is Required?

    Science.gov (United States)

    Rowe, C. M.; Oglesby, R. J.; Mawalagedara, R.; Mohammad Abadi Kamarei, A.

    2015-12-01

    Latin America and the Caribbean are at risk of extreme climate events, including flooding rains, damaging winds, drought, heat waves, and in high elevation mountainous regions, excessive snowfalls. The causes of these events are numerous - flooding rains and damaging winds are often associated with tropical cyclones, but also can occur, either separately or in tandem, due to smaller, more localized storms. Similarly, heat waves and droughts can be large scale or localized, and frequently occur together (as excessive drying can lead to enhanced heating, while enhanced heating in turn promotes additional drying). Even in the tropics, extreme snow and ice events can have severe consequences due to avalanches, and also impact water resources. Understanding and modeling the climate controls behind these extreme events requires consideration of a range of time and space scales. A common strategy is to use a global climate model (GCM) to simulate the large-scale (~100km) daily atmospheric controls on extreme events. A limited area, high resolution regional climate model (RCM) is then employed to dynamically downscale the results, so as to better incorporate the influence of topography and, secondarily, the nature of the land cover. But what resolution is required to provide the necessary results, i.e., minimize biases due to improper resolution? In conjunction with our partners from participating Latin American and Caribbean nations, we have made an extensive series of simulations, both region-wide and for individual countries, using the WRF regional climate model to downscale output from a variety of GCMs, as well as Reanalyses (as a proxy for observations). The simulations driven by the Reanalyses are used for robust model verification against actual weather station observations. The simulations driven by GCMs are designed to provide projections of future climate, including importantly how the nature and number of extreme events may change through coming decades. Our

  12. The December 2008 flood event in Rome: Was it really an extreme event?

    Science.gov (United States)

    Lastoria, B.; Mariani, S.; Casaioli, M.; Bussettini, M.

    2009-04-01

    In mid December 2008, Italy suffered bad weather with heavy snowfall blanketing the north and strong winds and downpours pelting the centre-south. In particular, during the period between 10th and 12th December, intense precipitation struck the Tyrrhenian Sea side of the peninsula, inducing a flood event, which captured the attention of the national and international media, on the Tiber river and on its tributary, the Aniene. The relevance of the event was caused by the actual damages occurred in several zones over Rome area, in particular due to the downpours and to damages which would have occurred if Tiber river had overflowed its banks. The event, which was initially considered as extreme, was indeed severe but not so exceptional as shown by the meteo-hydrological post-event analysis. The peak water level of 12.55 m, recorded on 13th December at 1:30 a.m. (local time) at the Ripetta station, which is situated along the Tiber river in the centre of Rome, was higher than those observed during the last ten years (which to the utmost reached 11.41 m in December 2005). However, it did not reach the historical maximum of 16.90 m observed in 1937. Moreover, on the basis of the Ripetta historical series, such a level is associated to an ordinary flood event. Even if the flood was ordinary, a state of emergency was declared by the Rome's Mayor, since the event caused severe damages by disrupting flight and train services, blocking off major roads leading into Rome, flooding underpasses and sealing off industrial activities sited in the flooded areas, in particular nearby the confluence of the Aniene river with the Tiber river. In addition, hundreds of people were evacuated and a woman died in a her car which was submerged by a wave of water and mud in an underpass. Given these premises, the present work examines the relation between a severe, but not extraordinary, event and the considerable damages that occurred as a consequence. First, the meteorological evolution of

  13. Impacts of the Future Changes in Extreme Events on the Regional Crop Yield in Turkey

    Science.gov (United States)

    An, Nazan; Turp, M. Tufan; Ozturk, Tugba; Kurnaz, M. Levent

    2016-04-01

    The changes in extreme events caused by climate change have the greatest impact on agricultural sector specifically crop yield. Therefore, it requires a clear understanding of how extreme events affect the crop yield and how it causes high economic losses. In this research, we cover the relationship between extreme events and the crop yield in Turkey for the period of 2020 - 2045 with respect to 1980 - 2005. We focus on the role of those extreme event causing natural disasters on the regional crop yield. This research comprises 2 parts. In the first part, the projection is performed according to the business as usual scenario of IPCC, RCP8.5, via the RegCM4.4 in order to obtain extreme event indices required for the crop assessment. In the second part, the crop yield and the extreme event indices are combined by applying the econometric analysis in order to see the relationship between natural disasters and crop yield. The risks for crop yield caused by the extreme events are estimated and interpreted. This study aims to assess the effect of frequency of expected extreme events on the crop yield at the cropland of Turkey. This research has been supported by Boǧaziçi University Research Fund Grant Number 10421.

  14. 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

  15. 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...

  16. Spatio-temporal extreme events in a laser with a saturable absorber

    CERN Document Server

    Rimoldi, Cristina; Prati, Franco; Tissoni, Giovanna

    2016-01-01

    We study extreme events occurring in the transverse $(x,y)$ section of the field emitted by a broad-area semiconductor laser with a saturable absorber. The spatio-temporal events on which we perform the statistical analysis are identified as maxima of the field intensity in the 3D space $(x,y,t)$. We identify regions in the parameter space where extreme events are more likely to occur and we study the connection of those extreme events with the cavity solitons that are known to exist in the same system, both stationary and self-pulsing.

  17. Extreme total column ozone events and effects on UV solar radiation at Thessaloniki, Greece

    Science.gov (United States)

    Fragkos, K.; Bais, A. F.; Fountoulakis, I.; Balis, D.; Tourpali, K.; Meleti, C.; Zanis, P.

    2016-11-01

    Thirty years of total ozone column (TOC) measurements conducted by a Brewer spectrophotometer, operating in Thessaloniki (40.6°) since March 1982, have been analyzed using the statistical extreme value theory for the identification of extreme TOC events. About 12 % of the total number of days with TOC measurements were identified as extreme-low and ˜15 % as extreme-high events. The influence of the extreme-low events on the annual mean TOC values is up to ˜18 DU, while the extreme-high events show lower impact (up to 12 DU). Removing the extreme events from the time series results in smoother year-to-year variability and reduction of the small long-term linear trend (-0.08 %/year) by a factor of 2. Furthermore, we examined the impact of the extreme events on the noon erythemal irradiance under clear skies, and we provide evidence that even under extreme-low TOC conditions, the UV radiation levels are determined to a great extent by the aerosol optical depth. Although the influence of aerosols is evident during all seasons, for spring and summer, the sensitivity of UV radiation is larger, probably due to the different nature of the aerosols over Thessaloniki during these seasons.

  18. Multi-model ensemble projections of future extreme heat stress on rice across southern China

    Science.gov (United States)

    He, Liang; Cleverly, James; Wang, Bin; Jin, Ning; Mi, Chunrong; Liu, De Li; Yu, Qiang

    2017-08-01

    Extreme heat events have become more frequent and intense with climate warming, and these heatwaves are a threat to rice production in southern China. Projected changes in heat stress in rice provide an assessment of the potential impact on crop production and can direct measures for adaptation to climate change. In this study, we calculated heat stress indices using statistical scaling techniques, which can efficiently downscale output from general circulation models (GCMs). Data across the rice belt in southern China were obtained from 28 GCMs in the Coupled Model Intercomparison Project phase 5 (CMIP5) with two emissions scenarios (RCP4.5 for current emissions and RCP8.5 for increasing emissions). Multi-model ensemble projections over the historical period (1960-2010) reproduced the trend of observations in heat stress indices (root-mean-square error RMSE = 6.5 days) better than multi-model arithmetic mean (RMSE 8.9 days) and any individual GCM (RMSE 11.4 days). The frequency of heat stress events was projected to increase by 2061-2100 in both scenarios (up to 185 and 319% for RCP4.5 and RCP8.5, respectively), especially in the middle and lower reaches of the Yangtze River. This increasing risk of exposure to heat stress above 30 °C during flowering and grain filling is predicted to impact rice production. The results of our study suggest the importance of specific adaption or mitigation strategies, such as selection of heat-tolerant cultivars and adjustment of planting date in a warmer future world.

  19. Soliciting Feedback from Resource Managers to Inform Response to Extreme Event Impact

    Science.gov (United States)

    Bedsworth, L. W.

    2014-12-01

    To date, extreme events have been defined by scientists through a top-down approach, relying on observations for current extremes and climate model projections based on future scenarios for their expected changes. These abstract definitions of extreme events are based on a corresponding characterization of what is "normal" and perhaps the choice of a threshold (e.g., a percentile of a historical distribution for a given climate variable), beyond which would represent an extreme event. However, there are not necessarily direct connections between these definitions and what is considered "extreme" in terms of impacts that challenge resource management. Several researchers have suggested that extreme event definitions would also be informed by input from on-the-ground resource managers who are familiar with the systems being impacted, the climate conditions that pose risks to those systems, and their resilience and adaptive capacity. This research will present preliminary survey work designed to solicit input from air and water quality managers in terms of what is considered an extreme event, how these events have been weathered in the past, and planned for in the future. The survey is based on literature review, interviews with air and water quality managers in California, and outreach to the scientific community. This work is the first step of a multistage research effort to link input from resource managers with scientific information to better inform air and water quality management and impacts of extreme events under a changing climate.

  20. Detecting impacts of extreme events with ecological in situ monitoring networks

    Directory of Open Access Journals (Sweden)

    M. D. Mahecha

    2017-09-01

    Full Text Available Extreme hydrometeorological conditions typically impact ecophysiological processes on land. Satellite-based observations of the terrestrial biosphere provide an important reference for detecting and describing the spatiotemporal development of such events. However, in-depth investigations of ecological processes during extreme events require additional in situ observations. The question is whether the density of existing ecological in situ networks is sufficient for analysing the impact of extreme events, and what are expected event detection rates of ecological in situ networks of a given size. To assess these issues, we build a baseline of extreme reductions in the fraction of absorbed photosynthetically active radiation (FAPAR, identified by a new event detection method tailored to identify extremes of regional relevance. We then investigate the event detection success rates of hypothetical networks of varying sizes. Our results show that large extremes can be reliably detected with relatively small networks, but also reveal a linear decay of detection probabilities towards smaller extreme events in log–log space. For instance, networks with  ≈  100 randomly placed sites in Europe yield a  ≥  90 % chance of detecting the eight largest (typically very large extreme events; but only a  ≥  50 % chance of capturing the 39 largest events. These findings are consistent with probability-theoretic considerations, but the slopes of the decay rates deviate due to temporal autocorrelation and the exact implementation of the extreme event detection algorithm. Using the examples of AmeriFlux and NEON, we then investigate to what degree ecological in situ networks can capture extreme events of a given size. Consistent with our theoretical considerations, we find that today's systematically designed networks (i.e. NEON reliably detect the largest extremes, but that the extreme event detection rates are not higher than would

  1. An Assessment of Direct and Indirect Economic Losses of Climatic Extreme Events

    Science.gov (United States)

    Otto, C.; Willner, S. N.; Wenz, L.; Levermann, A.

    2015-12-01

    Risk of extreme weather events like storms, heat extremes, and floods has already risen due to anthropogenic climate change and is likely to increase further under future global warming. Additionally, the structure of the global economy has changed importantly in the last decades. In the process of globalization, local economies have become more and more interwoven forming a complex network. Together with a trend towards lean production, this has resulted in a strong dependency of local manufacturers on global supply and value added chains, which may render the economic network more vulnerable to climatic extremes; outages of local manufacturers trigger indirect losses, which spread along supply chains and can even outstrip direct losses. Accordingly, in a comprehensive climate risk assessment these inter-linkages should be considered. Here, we present acclimate, an agent based dynamic damage propagation model. Its agents are production and consumption sites, which are interlinked by economic flows accounting for the complexity as well as the heterogeneity of the global supply network. Assessing the economic response on the timescale of the adverse event, the model permits to study temporal and spatial evolution of indirect production losses during the disaster and in the subsequent recovery phase of the economy. In this study, we focus on the dynamic economic resilience defined here as the ratio of direct to total losses. This implies that the resilience of the system under consideration is low if the high indirect losses are high. We find and assess a nonlinear dependence of the resilience on the disaster size. Further, we analyze the influence of the network structure upon resilience and discuss the potential of warehousing as an adaptation option.

  2. Research on Trends in Extreme Weather Events and their Effects on Grapevine in Romanian Viticulture

    Directory of Open Access Journals (Sweden)

    Georgeta Mihaela Bucur

    2016-11-01

    Full Text Available The aim of this work was to investigate the frequency and intensity of extreme weather events in various centers from Romania’s viticultural regions: winter frost, extreme temperatures during the growing season and summer droughts. Winter frost damaging the vine is a significant risk to grape production, mainly in the plains and lowlands to the foothills. The frequency of winter frost damaging the vine has increased during the last decades, in the context of climate change. Also, there has been found a significant increase in the number of hot days (Tmax > 30°C and very hot days (Tmax > 35°C. The evolution of these extreme events was followed in Craiova, Constanta, Bucharest, Timisoara, Cluj-Napoca, Oradea and Iasi, between 1977 and 2015. The long term study (18 years conducted in the experimental plantation of the University of Agronomic Sciences and Veterinary Medicine Bucharest revealed their influence on vine. During the last two decades, there has been registered a trend of increasing the frequency and intensity of winter frost, damaging vine (Tmin 30°C and > 35°C and droughts that adversely affect viticulture, production and quality of grapes and wine. The highest warming trends were observed for northern viticultural regions (Transylvania and Moldavia and for the seaside. Although the intensification of heat waves increases sugar accumulation in the berries, they trigger a significant reduction in grape production and in titrable acidity, requiring corrections and resulting in unbalanced wines. Meanwhile, droughts trigger production decrease. To avoid negative effects on vine, it is necessary to take measures, both on a short, medium and long term.

  3. Observed and projected urban extreme rainfall events in India

    Science.gov (United States)

    Ali, Haider; Mishra, Vimal; Pai, D. S.

    2014-11-01

    We examine changes in extreme rainfall indices over 57 major urban areas in India under the observed (1901-2010) and projected future climate (2010-2060). Between 1901 and 2010, only four out of the total 57 urban areas showed a significant (p-value urban areas experienced significant increases in the extreme rainfall indices for the different periods. Moreover, rainfall maxima for 1-10 day durations and at 100 year return period did not change significantly over the majority of urban areas in the post-1955 period. Results do not indicate any significant change (p > 0.05) in the pooled mean and distribution of the extreme rainfall indices for the pre- and post-1983 periods revealing an insignificant role of urbanization on rainfall extremes in the major urban areas in India. We find that at the majority of urban areas changes in the extreme rainfall indices are driven by large scale climate variability. Regional Climate Models (RCMs) that participated in the CORDEX-South Asia program showed a significant bias in the monsoon maximum rainfall and rainfall maxima at 100 year return period for the majority of urban areas. For instance, most of the models fail to simulate rainfall maxima within ±10% bias, which can be considered appropriate for a storm water design at many urban areas. Rainfall maxima at 1-3 day durations and 100 year return period is projected to increase significantly under the projected future climate at the majority of urban areas in India. The number of urban areas with significant increases in rainfall maxima under the projected future climate is far larger than the number of areas that experienced significant changes in the historic climate (1901-2010), which warrants a careful attention for urban storm water infrastructure planning and management.

  4. Responding to the Effects of Extreme Heat: Baltimore City's Code Red Program.

    Science.gov (United States)

    Martin, Jennifer L

    2016-01-01

    Heat response plans are becoming increasingly more common as US cities prepare for heat waves and other effects of climate change. Standard elements of heat response plans exist, but plans vary depending on geographic location and distribution of vulnerable populations. Because heat events vary over time and affect populations differently based on vulnerability, it is difficult to compare heat response plans and evaluate responses to heat events. This article provides an overview of the Baltimore City heat response plan, the Code Red program, and discusses the city's response to the 2012 Ohio Valley/Mid Atlantic Derecho, a complex heat event. Challenges with and strategies for evaluating the program are reviewed and shared.

  5. Seasonal and regional variations in extreme precipitation event frequency using CMIP5

    Science.gov (United States)

    Janssen, E.; Sriver, R. L.; Wuebbles, D. J.; Kunkel, K. E.

    2016-05-01

    Understanding how the frequency and intensity of extreme precipitation events are changing is important for regional risk assessments and adaptation planning. Here we use observational data and an ensemble of climate change model experiments (from the Coupled Model Intercomparison Project Phase 5 (CMIP5)) to examine past and potential future seasonal changes in extreme precipitation event frequency over the United States. Using the extreme precipitation index as a metric for extreme precipitation change, we find key differences between models and observations. In particular, the CMIP5 models tend to overestimate the number of spring events and underestimate the number of summer events. This seasonal shift in the models is amplified in projections. These results provide a basis for evaluating climate model skill in simulating observed seasonality and changes in regional extreme precipitation. Additionally, we highlight key sources of variability and uncertainty that can potentially inform regional impact analyses and adaptation planning.

  6. 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

  7. Identification of coronal heating events in 3D simulations

    Science.gov (United States)

    Kanella, Charalambos; Gudiksen, Boris V.

    2017-07-01

    Context. The solar coronal heating problem has been an open question in the science community since 1939. One of the proposed models for the transport and release of mechanical energy generated in the sub-photospheric layers and photosphere is the magnetic reconnection model that incorporates Ohmic heating, which releases a part of the energy stored in the magnetic field. In this model many unresolved flaring events occur in the solar corona, releasing enough energy to heat the corona. Aims: The problem with the verification and quantification of this model is that we cannot resolve small scale events due to limitations of the current observational instrumentation. Flaring events have scaling behavior extending from large X-class flares down to the so far unobserved nanoflares. Histograms of observable characteristics of flares show powerlaw behavior for energy release rate, size, and total energy. Depending on the powerlaw index of the energy release, nanoflares might be an important candidate for coronal heating; we seek to find that index. Methods: In this paper we employ a numerical three-dimensional (3D)-magnetohydrodynamic (MHD) simulation produced by the numerical code Bifrost, which enables us to look into smaller structures, and a new technique to identify the 3D heating events at a specific instant. The quantity we explore is the Joule heating, a term calculated directly by the code, which is explicitly correlated with the magnetic reconnection because it depends on the curl of the magnetic field. Results: We are able to identify 4136 events in a volume 24 × 24 × 9.5 Mm3 (i.e., 768 × 786 × 331 grid cells) of a specific snapshot. We find a powerlaw slope of the released energy per second equal to αP = 1.5 ± 0.02, and two powerlaw slopes of the identified volume equal to αV = 1.53 ± 0.03 and αV = 2.53 ± 0.22. The identified energy events do not represent all the released energy, but of the identified events, the total energy of the largest events

  8. Detection of quasiresonant amplification of planetary waves and their connection to northern hemisphere summer heat extremes

    Science.gov (United States)

    Kornhuber, Kai; Coumou, Dim; Petri, Stefan; Petoukhov, Vladimir

    2014-05-01

    Several recent northern hemisphere (NH) summer heat extremes have been linked to anomalous patterns of mid-latitudinal planetary waves , e.g. the European heat wave in 2003, the Russian Heat wave and Pakistani floods in 2010 and the US heat wave in 2011(Lau and Kim 2012, Black et al 2004, Petoukhov et al 2013). The NH large-scale circulation patterns in those years were characterized by persistent longitudinal planetary-scale high-amplitude waves of relative high wavenumber (6-8). A common mechanism that could lead to the observed high-amplitude planetary waves was proposed by Petukhov et al. (Petukhov et al 2013). Under certain conditions, free synoptic waves can be 'trapped' in a midlatitudinal waveguide while their amplitudes are amplified by a quasiresonant response to thermal and orographic forcing. We have searched the available reanalysis data for the emergence of waveguides for particular planetary waves and will present preliminary results of this analysis. Using spectral analysis, we quantify the planetary wave field in terms of wavenumber, amplitude, phase and eastward phase-propagation. We will present statistics of these wave quantities for periods with and without waveguides. With those conditions explicitly implemented in code we should be able to detect and point out the periods in time the requirements for amplification were met. By doing so the connection of actual summer month heat extremes to quasiresonance events can be assessed statistically. Black E., Blackburn M., Hoskins B. and Methven J.; 2004: Factors contributing to the summer 2003 European heatwave 217-23 Lau W. K. M. and Kim K.-M.; 2012: The 2010 Pakistan Flood and Russian Heat Wave: Teleconnection of Hydrometeorological Extremes J. Hydrometeorol. 13 392-403 Online: http://journals.ametsoc.org/doi/abs/10.1175/JHM-D-11-016.1 Petoukhov V., Rahmstorf S., Petri S. and Schellnhuber H .J.;2013: Quasi-resonant amplification of atmospheric planetary waves as a mechanism for recent Northern

  9. 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.

  10. Forecasting extreme wave events in moderate and high sea states

    Science.gov (United States)

    Magnusson, Anne Karin; Reistad, Magnar; Bitner-Gregersen, Elzbieta Maria

    2013-04-01

    Empirical studies on measurements have not yet come to conclusive relations between occurrence of rogue waves and - parameters which could be forecasted . Theoretical and tank experiments have demonstrated that high spectral peakedness and low spectral width combined (high Benjamin-Feir instability index, Onorato et al., 2006) give higher probability of rogue wave occurrence. Directional spread seems to reduce the probability of occurrence of rogue waves in these studies. Many years of experience with forecasting and discussions with people working in ocean environment indicate that rogue waves may as well occur in crossing seas. This was also indicated in a study in the Maxwave project (Toffoli et al., 2003) and the EXTREME SEAS project (Toffoli et al., 2011). We have here experimented with some indexes describing both high BFI and crossing seas and run the WAM model for some North Sea storm cases. Wave distributions measured at Ekofisk are analysed in the different cases. References • Onorato, M., Osborne, A., Serio, M., Cavaleri, L., Brandini, C., and Stansberg, C.: Extreme waves, modulational instability and second order theory: wave flume experiments on irregular waves,Europ. J. Mech. B/Fluids, 25, 586-601, 2006. • Toffoli, A., Lefevre, J.M., Monbaliu, J., Savina, H., and Bitner-Gregersen, E., "Freak Waves:Clues for Prediction in Ship Accidents?", Proc. ISOPE'2003 Conf. Hawai, USA, 2003. • Toffoli A., Bitner-Gregersen E. M., Osborne A. R., Serio M. Monbaliu J., Onorato M. (2011) Extreme Waves in Random Crossing Seas: Laboratory Experiments and Numerical Simulations. Geophys. Res. Lett., Vol. 38, L06605, 5 pp. doi: 10.1029/2011.

  11. Predicting the extreme 2015/16 El Nino event

    CSIR Research Space (South Africa)

    Mpheshea, LE

    2015-09-01

    Full Text Available state-of-the-art coupled ocean-atmosphere model’s Niño3.4 SST forecast for January 2016 is presented, followed by an evaluation of the model’s ability to have predicted events of similar magnitude in the past. The January forecast, initialized in July...

  12. The relationship between extreme weather events and crop losses in central Taiwan

    Science.gov (United States)

    Lai, Li-Wei

    2017-09-01

    The frequency of extreme weather events, which cause severe crop losses, is increasing. This study investigates the relationship between crop losses and extreme weather events in central Taiwan from 2003 to 2015 and determines the main factors influencing crop losses. Data regarding the crop loss area and meteorological information were obtained from government agencies. The crops were categorised into the following five groups: `grains', `vegetables', `fruits', `flowers' and `other crops'. The extreme weather events and their synoptic weather patterns were categorised into six and five groups, respectively. The data were analysed using the z score, correlation coefficient and stepwise regression model. The results show that typhoons had the highest frequency of all extreme weather events (58.3%). The largest crop loss area (4.09%) was caused by two typhoons and foehn wind in succession. Extreme wind speed coupled with heavy rainfall is an important factor affecting the losses in the grain and vegetable groups. Extreme wind speed is a common variable that affects the loss of `grains', `vegetables', `fruits' and `flowers'. Consecutive extreme weather events caused greater crop losses than individual events. Crops with long production times suffered greater losses than those with short production times. This suggests that crops with physical structures that can be easily damaged and long production times would benefit from protected cultivation to maintain food security.

  13. Extreme drought events in Germany during the last 60 yrs

    Science.gov (United States)

    Samaniego, L. E.; Kumar, R.; Zink, M.

    2011-12-01

    Droughts are among the most costly natural disasters because they heavily impact on the economy of a region as well as on its social and cultural activities. Droughts do not only occur in arid or semiarid regions but also in humid ones. The year 2007, for example, was the sunniest, hottest and driest in Germany in the last two centuries. In this case, it was too dry too early. As a result, the harvest was cut by half leading to enormous losses in the primary sector. Consumer prices of some agricultural products went up 26 percent. The purpose of this study is to identify the major agricultural and hydrological droughts in Germany since 1950 based on their severity, duration and areal extend. To achieve this goal, a 60-yr retrospective hydrological simulation of the land surface water budget over Germany was carried out with the process-based distributed hydrological model mHM. The model was forced with grided daily precipitation and temperature data at 4x4 km, and the model simulations were carried out at same spatial resolutions. Point measurement data from more than 5600 raingauges and about 1120 meteorological stations (DWD) were interpolated with EDK. Land cover change was also considered during this period. Drought indices were derived as monthly quantiles of the simulated fluxes which include root zone soil moisture and total runoff. A Gaussian kernel smoother was used to estimate these quantiles at each grid cell. A spatio-temporal cluster algorithm was used to consolidate all significant drought events. Main statistics such as magnitude, areal extend, duration, and severity were estimated only on those selected clusters. The mHM model was calibrated in major river basins giving Nash-Sutcliffe efficiencies for daily discharge simulations greater than 0.8 in the evaluation period. Plausibility tests between the simulated mHM soil moisture and land surface temperature from MODIS and regional climate model reanalysis data compared well. Results indicated that

  14. An Ensemble Approach to Extreme Space Weather Event Probability -- A First Look

    Science.gov (United States)

    Jonas, S.; Fronczyk, K.; McCarron, E.; Pratt, L. M.

    2015-12-01

    An extreme space weather event has the potential to disrupt or damage infrastructure systems and technologies that many societies rely on for economic and social wellbeing. Space weather events occur regularly, but extreme events occur less frequently with only several historical examples over the last 160 years. During the past decade, published works have (1) forensically examined the physical characteristics of the extreme historical events; and (2) discussed the probability or return rate of select extreme geomagnetic disturbances, including the 1859 Carrington event. Here we present an analysis of several of these studies. We created a unified statistical framework to visualize previous analyses, and developed a model from an ensemble using statistical methods. We look at geomagnetic disturbance probability across multiple return periods. We discuss what the most likely 100-year extreme event (a parameter of interest to policy makers and planners) and the return period for other extreme historical events. We discuss the current state of these analyses, their utility to policy makers and planners, the current limitations (in data and understanding) when compared to other hazards, and the gaps that need to be filled to enhance space weather risk assessments.

  15. 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...

  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. Coherent structures and extreme events in rotating multiphase turbulent flows

    CERN Document Server

    Biferale, Luca; Mazzitelli, Irene M; van Hinsberg, Michel A T; Lanotte, Alessandra S; Musacchio, Stefano; Perlekar, Prasad; Toschi, Federico

    2016-01-01

    By using direct numerical simulations (DNS) at unprecedented resolution we study turbulence under rotation in the presence of simultaneous direct and inverse cascades. The accumulation of energy at large scale leads to the formation of vertical coherent regions with high vorticity oriented along the rotation axis. By seeding the flow with millions of inertial particles, we quantify -for the first time- the effects of those coherent vertical structures on the preferential concentration of light and heavy particles. Furthermore, we quantitatively show that extreme fluctuations, leading to deviations from a normal-distributed statistics, result from the entangled interaction of the vertical structures with the turbulent background. Finally, we present the first-ever measurement of the relative importance between Stokes drag, Coriolis force and centripetal forces along the trajectories of inertial particles. We discover that vortical coherent structures lead to unexpected diffusion properties for heavy and light ...

  18. Coherent Structures and Extreme Events in Rotating Multiphase Turbulent Flows

    Directory of Open Access Journals (Sweden)

    L. Biferale

    2016-11-01

    Full Text Available By using direct numerical simulations (DNS at unprecedented resolution, we study turbulence under rotation in the presence of simultaneous direct and inverse cascades. The accumulation of energy at large scale leads to the formation of vertical coherent regions with high vorticity oriented along the rotation axis. By seeding the flow with millions of inertial particles, we quantify—for the first time—the effects of those coherent vertical structures on the preferential concentration of light and heavy particles. Furthermore, we quantitatively show that extreme fluctuations, leading to deviations from a normal-distributed statistics, result from the entangled interaction of the vertical structures with the turbulent background. Finally, we present the first-ever measurement of the relative importance between Stokes drag, Coriolis force, and centripetal force along the trajectories of inertial particles. We discover that vortical coherent structures lead to unexpected diffusion properties for heavy and light particles in the directions parallel and perpendicular to the rotation axis.

  19. Coherent Structures and Extreme Events in Rotating Multiphase Turbulent Flows

    Science.gov (United States)

    Biferale, L.; Bonaccorso, F.; Mazzitelli, I. M.; van Hinsberg, M. A. T.; Lanotte, A. S.; Musacchio, S.; Perlekar, P.; Toschi, F.

    2016-10-01

    By using direct numerical simulations (DNS) at unprecedented resolution, we study turbulence under rotation in the presence of simultaneous direct and inverse cascades. The accumulation of energy at large scale leads to the formation of vertical coherent regions with high vorticity oriented along the rotation axis. By seeding the flow with millions of inertial particles, we quantify—for the first time—the effects of those coherent vertical structures on the preferential concentration of light and heavy particles. Furthermore, we quantitatively show that extreme fluctuations, leading to deviations from a normal-distributed statistics, result from the entangled interaction of the vertical structures with the turbulent background. Finally, we present the first-ever measurement of the relative importance between Stokes drag, Coriolis force, and centripetal force along the trajectories of inertial particles. We discover that vortical coherent structures lead to unexpected diffusion properties for heavy and light particles in the directions parallel and perpendicular to the rotation axis.

  20. A hypothesis on nanodust as a source of energy for extreme weather events and climate changes

    Science.gov (United States)

    Berkovich, Simon

    2013-03-01

    There are many phenomena that attract energy, the source of which cannot be unerringly identified. Among those are: excess heat alleged to nuclear processes, sonoluminescence, wire fragmentation under high voltage pulses, diverse biophysical experiences, and some atmospheric effects, like ball lightning and terrestrial gamma rays. Destructive atmospheric events associated with intense air movements, such as hurricanes and tornadoes, expend huge amounts of energy equivalent to very many nuclear bombs. Our paper indicates a possibility for a new source of energy due to the so-called ``hot-clocking'' effect related to the holographic mechanism of the Universe that establishes the exclusive property of nonlocality. This may uncover energy in various unusual appearances, particularly, in the suspected trend of global warming as a direct contribution to the extreme weather events. The surmised clocking impacts from holographic reference beam can reveal themselves through gaseous aerosols and suspended contaminants that may have been increased with human technogenesis. According to recent EPRI report nanopowder for Ni-Pd alloys in the size range of 5-10 nm was found to cause small amounts of excess power, about 4 watt per gram. So, using a minimal norm of contamination (20 micrograms per cubic meter) as an approximate guide, we could estimate that the whole atmosphere would thus generate dozens of terawatts, a contribution comparable to that of the Sun.

  1. Extreme events following bifurcation to spatiotemporal chaos in a spatially extended microcavity laser

    Science.gov (United States)

    Coulibaly, S.; Clerc, M. G.; Selmi, F.; Barbay, S.

    2017-02-01

    The occurrence of extreme events in a spatially extended microcavity laser has been recently reported [Selmi et al., Phys. Rev. Lett. 116, 013901 (2016), 10.1103/PhysRevLett.116.013901] to be correlated to emergence of spatiotemporal chaos. In this dissipative system, the role of spatial coupling through diffraction is essential to observe the onset of spatiotemporal complexity. We investigate further the formation mechanism of extreme events by comparing the statistical and dynamical analyses. Experimental measurements together with numerical simulations allow us to assign the quasiperiodicity mechanism as the route to spatiotemporal chaos in this system. Moreover, by investigating the fine structure of the maximum Lyapunov exponent, of the Lyapunov spectrum, and of the Kaplan-Yorke dimension of the chaotic attractor, we are able to deduce that intermittency plays a key role in the proportion of extreme events measured. We assign the observed mechanism of generation of extreme events to quasiperiodic extended spatiotemporal intermittency.

  2. AgroClimate: Simulating and Monitoring the Risk of Extreme Weather Events from a Crop Phenology Perspective

    Science.gov (United States)

    Fraisse, C.; Pequeno, D.; Staub, C. G.; Perry, C.

    2016-12-01

    Climate variability, particularly the occurrence of extreme weather conditions such as dry spells and heat stress during sensitive crop developmental phases can substantially increase the prospect of reduced crop yields. Yield losses or crop failure risk due to stressful weather conditions vary mainly due to stress severity and exposure time and duration. The magnitude of stress effects is also crop specific, differing in terms of thresholds and adaptation to environmental conditions. To help producers in the Southeast USA mitigate and monitor the risk of crop losses due to extreme weather events we developed a web-based tool that evaluates the risk of extreme weather events during the season taking into account the crop development stages. Producers can enter their plans for the upcoming season in a given field (e.g. crop, variety, planting date, acreage etc.), select or not a specific El Nino Southern Oscillation (ENSO) phase, and will be presented with the probabilities (ranging from 0 -100%) of extreme weather events occurring during sensitive phases of the growing season for the selected conditions. The DSSAT models CERES-Maize, CROPGRO-Soybean, CROPGRO-Cotton, and N-Wheat phenology models have been translated from FORTRAN to a standalone versions in R language. These models have been tested in collaboration with Extension faculty and producers during the 2016 season and their usefulness for risk mitigation and monitoring evaluated. A companion AgroClimate app was also developed to help producers track and monitor phenology development during the cropping season.

  3. Power System Extreme Event Detection: The Vulnerability Frontier

    OpenAIRE

    Lesieutre, Bernard C.; Pinar, Ali; Roy, Sandip

    2007-01-01

    In this work we apply graph theoretic tools to provide a close bound on a frontier relating the number of line outages in a grid to the power disrupted by the outages. This frontier describes the boundary of a space relating the possible severity of a disturbance in terms of power disruption, from zero to some maximum on the boundary, to the number line outages involved in the event. We present the usefulness of this analysis with a complete analysis of a 30 bus system, and present resul...

  4. Not ready for prime time: transitional events in the extremely preterm infant.

    Science.gov (United States)

    Armentrout, Debra

    2014-01-01

    Successful transition from intrauterine to extrauterine life involves significant physiologic changes. The majority of these changes occur relatively quickly during those first moments following delivery; however, transition for the extremely preterm infant occurs over a longer period of time. Careful assessment and perceptive interventions on the part of neonatal care providers is essential as the extremely preterm infant adjusts to life outside the womb. This article will focus on respiratory, cardiovascular, gastrointestinal, and neurologic transitional events experienced by the extremely premature infant.

  5. The differential effects of increasing frequency and magnitude of extreme events on coral populations

    OpenAIRE

    Fabina, NS; Baskett, ML; K. Gross

    2015-01-01

    © 2015 by the Ecological Society of America. Extreme events, which have profound ecological consequences, are changing in both frequency and magnitude with climate change. Because extreme temperatures induce coral bleaching, we can explore the relative impacts of changes in frequency and magnitude of high temperature events on coral reefs. Here, we combined climate projections and a dynamic population model to determine how changing bleaching regimes influence coral persistence. We additional...

  6. Soil biotic legacy effects of extreme weather events influence plant invasiveness

    NARCIS (Netherlands)

    Meisner, A.; De Deyn, G.B.; De Boer, W.; Van der Putten, W.H.

    2013-01-01

    Climate change is expected to increase future abiotic stresses on ecosystems through extreme weather events leading to more extreme drought and rainfall incidences [Jentsch A, et al. (2007) Front Ecol Environ 5(7):365–374]. These fluctuations in precipitation may affect soil biota, soil processes [E

  7. Extreme events statistics in a two-layer quasi-geostrophic atmospheric model

    Science.gov (United States)

    Galfi, Vera Melinda; Bodai, Tamas; Lucarini, Valerio

    2016-04-01

    Extreme events statistics provides a theoretical framework to analyze and predict extreme events based on the convergence of the distribution of the extremes to some limiting distribution. In this work we analyze the convergence of the distribution of extreme events to the Generalized Extreme Value (GEV) distribution and to the Generalized Pareto Distribution (GPD), using a two-layer quasi-geostrophic atmospheric model, and compare our results with theoretical findings from the field of extreme value theory for dynamical systems. We study the behavior of the GEV shape parameter by increasing the block size and of the GPD shape parameter by increasing the threshold, and compare the inferred parameters with a theoretical shape parameter that depends only on the geometrical properties of the attractor. The main objective is to find out whether this theoretical shape parameter can be used to evaluate extreme event analysis based on model output. For this, we perform very long simulations. We run our system with two different levels of forcing determined by two different meridional temperature gradients, one inducing a medium level of chaos and the other one a high level of chaos. We analyze in both cases extremes of energy variables.

  8. Triggering extreme events at the nanoscale in photonic seas

    KAUST Repository

    Liu, Changxu

    2015-03-09

    Hurricanes, tsunamis, rogue waves and tornadoes are rare natural phenomena that embed an exceptionally large amount of energy, which appears and quickly disappears in a probabilistic fashion. This makes them difficult to predict and hard to generate on demand. Here we demonstrate that we can trigger the onset of rare events akin to rogue waves controllably, and systematically use their generation to break the diffraction limit of light propagation. We illustrate this phenomenon in the case of a random field, where energy oscillates among incoherent degrees of freedom. Despite the low energy carried by each wave, we illustrate how to control a mechanism of spontaneous synchronization, which constructively builds up the spectral energy available in the whole bandwidth of the field into giant structures, whose statistics is predictable. The larger the frequency bandwidth of the random field, the larger the amplitude of rare events that are built up by this mechanism. Our system is composed of an integrated optical resonator, realized on a photonic crystal chip. Through near-field imaging experiments, we record confined rogue waves characterized by a spatial localization of 206 nm and with an ultrashort duration of 163 fs at a wavelength of 1.55 μm. Such localized energy patterns are formed in a deterministic dielectric structure that does not require nonlinear properties.

  9. Power outages, extreme events and health: a systematic review of the literature from 2011-2012.

    Science.gov (United States)

    Klinger, Chaamala; Landeg, Owen; Murray, Virginia

    2014-01-02

    Background Extreme events (e.g. flooding) threaten critical infrastructure including power supplies. Many interlinked systems in the modern world depend on a reliable power supply to function effectively. The health sector is no exception, but the impact of power outages on health is poorly understood. Greater understanding is essential so that adverse health impacts can be prevented and/or mitigated. Methods We searched Medline, CINAHL and Scopus for papers about the health impacts of power outages during extreme events published in 2011-2012. A thematic analysis was undertaken on the extracted information. The Public Health England Extreme Events Bulletins between 01/01/2013 - 31/03/2013 were used to identify extreme events that led to power outages during this three-month period. Results We identified 20 relevant articles. Power outages were found to impact health at many levels within diverse settings. Recurrent themes included the difficulties of accessing healthcare, maintaining frontline services and the challenges of community healthcare. We identified 52 power outages in 19 countries that were the direct consequence of extreme events during the first three months of 2013. Conclusions To our knowledge, this is the first review of the health impacts of power outages. We found the current evidence and knowledge base to be poor. With scientific consensus predicting an increase in the frequency and magnitude of extreme events due to climate change, the gaps in knowledge need to be addressed in order to mitigate the impact of power outages on global health.

  10. Effect of latent heating on mesoscale vortex development during extreme precipitation: Colorado, September 2013

    Science.gov (United States)

    Morales, Annareli

    From 9-16 September 2013, a slow-moving cut-off low in the southwestern U.S. funneled unseasonal amounts of moisture to the Colorado Front Range, resulting in extreme precipitation and flooding. The heaviest precipitation during the September 2013 event occurred over the northern Colorado Front Range, producing a 7-day total of over 380 mm of rain. The flash flooding caused over $3 billion in damage to property and infrastructure and resulted in eight fatalities. This study will focus on the precipitation and mesoscale features during 11-12 September 2013 in Boulder, CO. During the evening of 11 September, Boulder experienced flash flooding as a result of high rain rates accumulating over 180 mm of rain in 6 hours. From 0400-0700 UTC 12 September, a mesoscale vortex (mesovortex) was observed to travel northwestward towards Boulder. This circulation enhanced upslope flow and was associated with localized deep convection. The mesovortex originated in an area common for the development of a lee vortex known as the Denver Cyclone. We hypothesize that this mesoscale vortex is not associated with lee vortex formation, such as the Denver Cyclone, but developed through the release of latent heat from microphysical process. The Advanced Research Weather Research and Forecast (ARW) model was used to 1) produce a control simulation that properly represented the evolution and processes of interest during the event and 2) test the importance of latent heating to the development and evolution of the mesovortex. The results from various latent heating experiments suggested that the mesovortex did not develop through lee vortex formation and the latent heat released just before and during the mesovortex event was important to its development. Results also showed latent heating affected the flow field, resulting in a positive feedback between the circulation, associated low-level jet, and convection leading to further upslope flow and precipitation development. Further experiments

  11. Recent advances on reconstruction of climate and extreme events in China for the past 2000 year

    Science.gov (United States)

    Zheng, Jingyun; Hao, Zhixin; Ge, Quansheng; Liu, Yang

    2016-04-01

    of 1500-1900 were more frequent than that after 1950. The intensity of regional heat wave occurred in the context of recent global warming may not exceed the natural climate variability during the historical times. In the eastern monsoon region of China, the significant cycles of precipitation are 90-100a, 70-80a, 43-48a, 35a, 25-27a and 17-18a in North China Plain; 90-100a, 73-75a, 63-68a, 55a, 45a, 37a and 26a in Jiang-Huai area; and 85-100a, 75-77a, 58-65a, 37-39a, 31a and 26a in Jiang-Nan area; respectively. Whereas, the spatial pattern of drought/flood for all cold periods ensemble mean showed an east to west distribution, but for all warm periods ensemble mean showed a tri-pole pattern with drought in south of 25°N, flood in 25°-30°N, and drought in north of 30°N. The extreme drought events were more frequent at the periods of 301-400, 751-800, 1051-1150, 1501-1550 and 1601-1650, the extreme flood events were more frequent at the periods of 101-150, 251-300, 951-1000, 1701-1750, 1801-1850 and 1901-1950, and for the period of 1551-1600, the coexisting extreme drought and extreme flood events most frequently occurred. In arid area, China, it was characterized by a relatively dry in AD 1000-1350, a wet in AD 1500 to 1850 and tending to moisture in recent decades. In the northeastern Qinghai-Tibetan Plateau, there existed evident centennial oscillations for precipitation during the past 1000 years, with interruption of several multi-decadal severe drought events, which two prominent droughty events centered on AD1480s and AD 1710s. In the Southwest of China, the extreme droughts as severe as in Sichuan and Chongqing in 2006 have also been occurred during the historical times.

  12. Temporal energy partitions of Florida extreme sea level events as a function of Atlantic multidecadal oscillation

    Directory of Open Access Journals (Sweden)

    J. Park

    2010-06-01

    Full Text Available An energy-conservative metric based on the discrete wavelet transform is applied to assess the relative energy distribution of extreme sea level events across different temporal scales. The metric is applied to coastal events at Key West and Pensacola Florida as a function of two Atlantic Multidecadal Oscillation (AMO regimes. Under AMO warm conditions there is a small but significant redistribution of event energy from nearly static into more dynamic (shorter duration timescales at Key West, while at Pensacola the AMO-dependent changes in temporal event behaviour are less pronounced. Extreme events with increased temporal dynamics might be consistent with an increase in total energy of event forcings which may be a reflection of more energetic storm events during AMO warm phases. As dynamical models mature to the point of providing regional climate index predictability, coastal planners may be able to consider such temporal change metrics in planning scenarios.

  13. Temporal energy partitions of Florida extreme sea level events as a function of Atlantic multidecadal oscillation

    Directory of Open Access Journals (Sweden)

    J. Park

    2010-03-01

    Full Text Available An energy-conservative metric based on the discrete wavelet transform is applied to assess the relative energy distribution of non-stationary extreme sea level events across different temporal scales. The metric is applied to coastal events at Key West and Pensacola Florida as a function of two Atlantic Multidecadal Oscillation (AMO regimes. Under AMO warm conditions there is a small but significant redistribution of event energy from nearly static into more dynamic timescales at Key West, while at Pensacola the AMO-dependent changes in temporal event behaviour are less pronounced. Extreme events with increased temporal dynamics are consistent with an increase in total energy of event forcings which may be a reflection of more energetic storm events during AMO warm phases. As dynamical models mature to the point of providing regional climate index predictability, coastal planners may be able to consider such temporal change metrics in planning scenarios.

  14. The magnitude and effects of extreme solar particle events

    Directory of Open Access Journals (Sweden)

    Jiggens Piers

    2014-06-01

    Full Text Available The solar energetic particle (SEP radiation environment is an important consideration for spacecraft design, spacecraft mission planning and human spaceflight. Herein is presented an investigation into the likely severity of effects of a very large Solar Particle Event (SPE on technology and humans in space. Fluences for SPEs derived using statistical models are compared to historical SPEs to verify their appropriateness for use in the analysis which follows. By combining environment tools with tools to model effects behind varying layers of spacecraft shielding it is possible to predict what impact a large SPE would be likely to have on a spacecraft in Near-Earth interplanetary space or geostationary Earth orbit. Also presented is a comparison of results generated using the traditional method of inputting the environment spectra, determined using a statistical model, into effects tools and a new method developed as part of the ESA SEPEM Project allowing for the creation of an effect time series on which statistics, previously applied to the flux data, can be run directly. The SPE environment spectra is determined and presented as energy integrated proton fluence (cm−2 as a function of particle energy (in MeV. This is input into the SHIELDOSE-2, MULASSIS, NIEL, GRAS and SEU effects tools to provide the output results. In the case of the new method for analysis, the flux time series is fed directly into the MULASSIS and GEMAT tools integrated into the SEPEM system. The output effect quantities include total ionising dose (in rads, non-ionising energy loss (MeV g−1, single event upsets (upsets/bit and the dose in humans compared to established limits for stochastic (or cancer-causing effects and tissue reactions (such as acute radiation sickness in humans given in grey-equivalent and sieverts respectively.

  15. Super-extreme event's influence on a Weierstrass-Mandelbrot Continuous-Time Random Walk

    CERN Document Server

    Gubiec, Tomasz; Kutner, Ryszard; Sornette, Didier

    2010-01-01

    Two utmost cases of super-extreme event's influence on the velocity autocorrelation function (VAF) were considered. The VAF itself was derived within the hierarchical Weierstrass-Mandelbrot Continuous-Time Random Walk (WM-CTRW) formalism, which is able to cover a broad spectrum of continuous-time random walks. Firstly, we studied a super-extreme event in a form of a sustained drift, whose duration time is much longer than that of any other event. Secondly, we considered a super-extreme event in the form of a shock with the size and velocity much larger than those corresponding to any other event. We found that the appearance of these super-extreme events substantially changes the results determined by extreme events (the so called "black swans") that are endogenous to the WM-CTRW process. For example, changes of the VAF in the latter case are in the form of some instability and distinctly differ from those caused in the former case. In each case these changes are quite different compared to the situation with...

  16. 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

  17. 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

  18. "Extreme events" in STT-MRAM speed retention and reliability (Conference Presentation)

    Science.gov (United States)

    Wang, Xiaobin; Zhang, Jing; Wang, Zihui; Hao, Xiaojie; Zhou, Yuchen; Gan, Huadong; Jun, Dongha; Satoh, Kimihiro; Yen, Bing K.; Huai, Yiming

    2016-10-01

    Fast operation speed, high retention and high reliability are the most attractive features of the spin transfer torque magnetic random access memory (STT-MRAM) based upon perpendicular magnetic tunneling junction (pMTJ). For state-of-the-art pMTJ STT-MRAM, its device performance is fundamentally determined by material "extreme events" physics. For example, nanosecond write bit error rate is determined by extremely high probability (>(1-10^(-7))) stochastic magnetization switching events, retention is determined by magnetization configurations with extremely low switching probability, reliability is determined by extremely low probability (MRAM write, read, retention and reliability. Specifically, we will present our model that accurately calculates extremely low write BER for various magnetization configurations. We will review our study of thermal magnetization switching through the dynamic optimal reversal path approach, capable of characterizing extreme thermal magnetization switching events under both low frequency (e.g. static retention) and high frequency (e.g. fast read) excitations. We will also discuss a new MTJ breakdown reliability model that quantifies extreme events uniformly at different failure mode regions.

  19. Economic Evaluations of the Health Impacts of Weather-Related Extreme Events: A Scoping Review.

    Science.gov (United States)

    Schmitt, Laetitia H M; Graham, Hilary M; White, Piran C L

    2016-11-08

    The frequency and severity of extreme events is expected to increase under climate change. There is a need to understand the economic consequences of human exposure to these extreme events, to underpin decisions on risk reduction. We undertook a scoping review of economic evaluations of the adverse health effects from exposure to weather-related extreme events. We searched PubMed, Embase and Web of Science databases with no restrictions to the type of evaluations. Twenty studies were included, most of which were recently published. Most studies have been undertaken in the U.S. (nine studies) or Asia (seven studies), whereas we found no studies in Africa, Central and Latin America nor the Middle East. Extreme temperatures accounted for more than a third of the pool of studies (seven studies), closely followed by flooding (six studies). No economic study was found on drought. Whilst studies were heterogeneous in terms of objectives and methodology, they clearly indicate that extreme events will become a pressing public health issue with strong welfare and distributional implications. The current body of evidence, however, provides little information to support decisions on the allocation of scarce resources between risk reduction options. In particular, the review highlights a significant lack of research attention to the potential cost-effectiveness of interventions that exploit the capacity of natural ecosystems to reduce our exposure to, or ameliorate the consequences of, extreme events.

  20. Economic Evaluations of the Health Impacts of Weather-Related Extreme Events: A Scoping Review

    Directory of Open Access Journals (Sweden)

    Laetitia H. M. Schmitt

    2016-11-01

    Full Text Available The frequency and severity of extreme events is expected to increase under climate change. There is a need to understand the economic consequences of human exposure to these extreme events, to underpin decisions on risk reduction. We undertook a scoping review of economic evaluations of the adverse health effects from exposure to weather-related extreme events. We searched PubMed, Embase and Web of Science databases with no restrictions to the type of evaluations. Twenty studies were included, most of which were recently published. Most studies have been undertaken in the U.S. (nine studies or Asia (seven studies, whereas we found no studies in Africa, Central and Latin America nor the Middle East. Extreme temperatures accounted for more than a third of the pool of studies (seven studies, closely followed by flooding (six studies. No economic study was found on drought. Whilst studies were heterogeneous in terms of objectives and methodology, they clearly indicate that extreme events will become a pressing public health issue with strong welfare and distributional implications. The current body of evidence, however, provides little information to support decisions on the allocation of scarce resources between risk reduction options. In particular, the review highlights a significant lack of research attention to the potential cost-effectiveness of interventions that exploit the capacity of natural ecosystems to reduce our exposure to, or ameliorate the consequences of, extreme events.

  1. 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.

  2. 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...

  3. Roadmap on optical rogue waves and extreme events

    Science.gov (United States)

    Akhmediev, Nail; Kibler, Bertrand; Baronio, Fabio; Belić, Milivoj; Zhong, Wei-Ping; Zhang, Yiqi; Chang, Wonkeun; Soto-Crespo, Jose M.; Vouzas, Peter; Grelu, Philippe; Lecaplain, Caroline; Hammani, K.; Rica, S.; Picozzi, A.; Tlidi, Mustapha; Panajotov, Krassimir; Mussot, Arnaud; Bendahmane, Abdelkrim; Szriftgiser, Pascal; Genty, Goery; Dudley, John; Kudlinski, Alexandre; Demircan, Ayhan; Morgner, Uwe; Amiraranashvili, Shalva; Bree, Carsten; Steinmeyer, Günter; Masoller, C.; Broderick, Neil G. R.; Runge, Antoine F. J.; Erkintalo, Miro; Residori, S.; Bortolozzo, U.; Arecchi, F. T.; Wabnitz, Stefan; Tiofack, C. G.; Coulibaly, S.; Taki, M.

    2016-06-01

    The pioneering paper ‘Optical rogue waves’ by Solli et al (2007 Nature 450 1054) started the new subfield in optics. This work launched a great deal of activity on this novel subject. As a result, the initial concept has expanded and has been enriched by new ideas. Various approaches have been suggested since then. A fresh look at the older results and new discoveries has been undertaken, stimulated by the concept of ‘optical rogue waves’. Presently, there may not by a unique view on how this new scientific term should be used and developed. There is nothing surprising when the opinion of the experts diverge in any new field of research. After all, rogue waves may appear for a multiplicity of reasons and not necessarily only in optical fibers and not only in the process of supercontinuum generation. We know by now that rogue waves may be generated by lasers, appear in wide aperture cavities, in plasmas and in a variety of other optical systems. Theorists, in turn, have suggested many other situations when rogue waves may be observed. The strict definition of a rogue wave is still an open question. For example, it has been suggested that it is defined as ‘an optical pulse whose amplitude or intensity is much higher than that of the surrounding pulses’. This definition (as suggested by a peer reviewer) is clear at the intuitive level and can be easily extended to the case of spatial beams although additional clarifications are still needed. An extended definition has been presented earlier by N Akhmediev and E Pelinovsky (2010 Eur. Phys. J. Spec. Top. 185 1-4). Discussions along these lines are always useful and all new approaches stimulate research and encourage discoveries of new phenomena. Despite the potentially existing disagreements, the scientific terms ‘optical rogue waves’ and ‘extreme events’ do exist. Therefore coordination of our efforts in either unifying the concept or in introducing alternative definitions must be continued. From

  4. General Population Knowledge about Extreme Heat: A Cross-Sectional Survey in Lisbon and Madrid.

    Science.gov (United States)

    Gil Cuesta, Julita; van Loenhout, Joris Adriaan Frank; Colaço, Maria da Conceição; Guha-Sapir, Debarati

    2017-01-28

    Extreme heat is associated with an increased mortality and morbidity. National heat plans have been implemented to minimize the effect of extreme heat. The population's awareness and knowledge of national heat plans and extreme heat is essential to improve the community's behavior and adaptation. A general population survey was conducted in Lisbon and in Madrid to assess this knowledge. We used a questionnaire to interview passers-by. Results were compared between Lisbon and Madrid and between locals and foreigners, using Pearson Chi-square tests and Fisher's exact test. We conducted 260 interviews in six locations of different socio-economic backgrounds in each city. The most frequently mentioned extreme heat-related risk groups were the elderly (79.2%), children (49.6%) and babies (21.5%). The most frequently reported protective measures were increased fluid intake (73.1%) and avoiding exposure to the sun (50.8%). Knowledge about the heat plan was higher in Lisbon (37.2%) than in Madrid (25.2%) (p-value = 0.03). Foreigners had less knowledge of risk groups compared to locals. Heat plans were not widely known in Madrid and Lisbon. Nonetheless, knowledge of practical concepts to face extreme heat, such as certain risk groups and protective measures, was found. Our results were similar to comparable surveys where specific respondents' groups were identified as less knowledgeable. This highlighted the importance of addressing these groups when communicating public health messages on heat. Foreigners should be specifically targeted to increase their awareness.

  5. 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.

  6. It's the Heat AND the Humidity -- Assessment of Extreme Heat Scenarios to Enable the Assessment of Climate Impacts on Public Health

    Science.gov (United States)

    Crosson, William L; Al-Hamdan, Mohammad Z.; Economou, Sigrid, A.; Estes, Maurice G.; Estes, Sue M.; Puckett, Mark; Quattrochi, Dale A

    2013-01-01

    In the United States, extreme heat is the most deadly weather-related hazard. In the face of a warming climate and urbanization, which contributes to local-scale urban heat islands, it is very likely that extreme heat events (EHEs) will become more common and more severe in the U.S. In a NASA-funded project supporting the National Climate Assessment, we are providing historical and future measures of extreme heat to enable assessments of the impacts of heat on public health over the coterminous U.S. We use atmospheric temperature and humidity information from meteorological reanalysis and from Global Climate Models (GCMs) to provide data on past and future heat events. The project s emphasis is on providing assessments of the magnitude, frequency and geographic distribution of extreme heat in the U.S. to facilitate public health studies. In our approach, long-term climate change is captured with GCM output, and the temporal and spatial characteristics of short-term extremes are represented by the reanalysis data. Two future time horizons, 2040 and 2090, are the focus of future assessments; these are compared to the recent past period of 1981-2000. We are characterizing regional-scale temperature and humidity conditions using GCM output for two climate change scenarios (A2 and A1B) defined in the Special Report on Emissions Scenarios (SRES). For each future period, 20 years of multi-model GCM output have been analyzed to develop a heat stress climatology based on statistics of extreme heat indicators. Differences between the two future and past periods have been used to define temperature and humidity changes on a monthly time scale and regional spatial scale. These changes, combined with hourly historical meteorological data at a spatial scale (12 km) much finer than that of GCMs, enable us to create future climate realizations, from which we compute the daily heat stress measures and related spatially-specific climatological fields. These include the mean annual

  7. Planning support system for climate adaptation: Composing effective sets of blue-green measures to reduce urban vulnerability to extreme weather events

    NARCIS (Netherlands)

    Voskamp, I.M.; Ven, Van de F.H.M.

    2015-01-01

    The risk of pluvial flooding, heat stress and drought is increasing due to climate change. To increase urban resilience to extreme weather events, it is essential to combine green and blue infrastructure and link enhanced storage capacity in periods of water surplus with moments of water shortage as

  8. Planning support system for climate adaptation: Composing effective sets of blue-green measures to reduce urban vulnerability to extreme weather events

    NARCIS (Netherlands)

    Voskamp, I.M.; Ven, Van de F.H.M.

    2015-01-01

    The risk of pluvial flooding, heat stress and drought is increasing due to climate change. To increase urban resilience to extreme weather events, it is essential to combine green and blue infrastructure and link enhanced storage capacity in periods of water surplus with moments of water shortage as

  9. 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.

  10. 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.

  11. The Role of Axisymmetric Reconnection Events in JET Discharges with Extreme Shear Reversal

    Energy Technology Data Exchange (ETDEWEB)

    B.C. Stratton; J.A. Breslau; R.V. Budny; S.C. Jardin; W. Park; H.R. Strauss; L.E. Zakharov; B. Alper; V. Drozdov; N.C. Hawkes; S. Reyes-Cortes; and Contributors to the EFDA-JET Work Programme

    2001-12-03

    Injection of Lower Hybrid Heating and Current Drive into the current ramp-up phase of Joint European Torus (JET) discharges can produce extremely reversed q-profiles characterized by a core region of very small or zero current density (within Motional Stark Effect diagnostic measurement errors) and q(subscript min) > 1. T(subscript e)-profiles show sawtooth-like collapses and the presence of an internal transport barrier. Accurate equilibrium reconstructions of these discharges are obtained using the ESC code, which was recently extended to allow equilibrium reconstructions in which a free boundary solver determines the plasma boundary and a fixed boundary solver provides the magnetic geometry and current density profile. The core current density does not appear to go negative, although current diffusion calculations indicate that sufficient non-inductive current drive to cause this is present. This is explained by nonlinear resistive MHD simulations in toroidal geometry which predict that these discharges undergo n=0 reconnection events (axisymmetric sawteeth) that redistribute the current to hold the core current density near zero.

  12. Extreme weather events: Should drinking water quality management systems adapt to changing risk profiles?

    Science.gov (United States)

    Khan, Stuart J; Deere, Daniel; Leusch, Frederic D L; Humpage, Andrew; Jenkins, Madeleine; Cunliffe, David

    2015-11-15

    Among the most widely predicted and accepted consequences of global climate change are increases in both the frequency and severity of a variety of extreme weather events. Such weather events include heavy rainfall and floods, cyclones, droughts, heatwaves, extreme cold, and wildfires, each of which can potentially impact drinking water quality by affecting water catchments, storage reservoirs, the performance of water treatment processes or the integrity of distribution systems. Drinking water guidelines, such as the Australian Drinking Water Guidelines and the World Health Organization Guidelines for Drinking-water Quality, provide guidance for the safe management of drinking water. These documents present principles and strategies for managing risks that may be posed to drinking water quality. While these principles and strategies are applicable to all types of water quality risks, very little specific attention has been paid to the management of extreme weather events. We present a review of recent literature on water quality impacts of extreme weather events and consider practical opportunities for improved guidance for water managers. We conclude that there is a case for an enhanced focus on the management of water quality impacts from extreme weather events in future revisions of water quality guidance documents.

  13. Recent changes in extreme rainfall events in Peninsular Malaysia: 1971-2005

    Science.gov (United States)

    Wan Zin, Wan Zawiah; Jamaludin, Suhaila; Deni, Sayang Mohd; Jemain, Abdul Aziz

    2009-05-01

    This paper assesses recent changes in extremes of annual rainfall in Peninsular Malaysia based on daily rainfall data for ten rain-gauged stations over the period 1971-2005. Eight indices that represent the extreme events are defined and analyzed. Maps of trends for these indices, which are extreme dry spell (XDS), extreme rain sum (XRS), extreme wet day intensities at 95% and 99% percentiles (I95 and I99), proportion of extreme wet day to the total wet day (R95 and R99), and frequency of extreme wet day at 95% and 99% percentiles (N95 and N99), were analyzed based on annual data and seasons. When the indices are evaluated annually, the Mann-Kendall and linear regression trend tests showed increasing trends in the extreme intensity indices (I95 and I99) at two stations. A significant decrease in N99, associated with the frequency of extremely wet days, was observed at 60% of the stations. The change points for these indices are found to occur in the period of the 1980s. There is no significant trend detected for XDS, XRS, and proportion of extreme rainfall over total rainfall amount indices during the period considered in this study. Descriptive analysis of indices during the monsoon period showed that the annual spatial pattern for the peninsula is very much influenced by the northeast monsoon where the highest mean values for majority of the indices occur during this time period.

  14. Managing Expectations: Results from Case Studies of US Water Utilities on Preparing for, Coping with, and Adapting to Extreme Events

    Science.gov (United States)

    Beller-Simms, N.; Metchis, K.

    2014-12-01

    Water utilities, reeling from increased impacts of successive extreme events such as floods, droughts, and derechos, are taking a more proactive role in preparing for future incursions. A recent study by Federal and water foundation investigators, reveals how six US water utilities and their regions prepared for, responded to, and coped with recent extreme weather and climate events and the lessons they are using to plan future adaptation and resilience activities. Two case studies will be highlighted. (1) Sonoma County, CA, has had alternating floods and severe droughts. In 2009, this area, home to competing water users, namely, agricultural crops, wineries, tourism, and fisheries faced a three-year drought, accompanied at the end by intense frosts. Competing uses of water threatened the grape harvest, endangered the fish industry and resulted in a series of regulations, and court cases. Five years later, new efforts by partners in the entire watershed have identified mutual opportunities for increased basin sustainability in the face of a changing climate. (2) Washington DC had a derecho in late June 2012, which curtailed water, communications, and power delivery during a record heat spell that impacted hundreds of thousands of residents and lasted over the height of the tourist-intensive July 4th holiday. Lessons from this event were applied three months later in anticipation of an approaching Superstorm Sandy. This study will help other communities in improving their resiliency in the face of future climate extremes. For example, this study revealed that (1) communities are planning with multiple types and occurrences of extreme events which are becoming more severe and frequent and are impacting communities that are expanding into more vulnerable areas and (2) decisions by one sector can not be made in a vacuum and require the scientific, sectoral and citizen communities to work towards sustainable solutions.

  15. Ensemble reconstruction of spatio-temporal extreme low-flow events in France since 1871

    Science.gov (United States)

    Caillouet, Laurie; Vidal, Jean-Philippe; Sauquet, Eric; Devers, Alexandre; Graff, Benjamin

    2017-06-01

    The length of streamflow observations is generally limited to the last 50 years even in data-rich countries like France. It therefore offers too small a sample of extreme low-flow events to properly explore the long-term evolution of their characteristics and associated impacts. To overcome this limit, this work first presents a daily 140-year ensemble reconstructed streamflow dataset for a reference network of near-natural catchments in France. This dataset, called SCOPE Hydro (Spatially COherent Probabilistic Extended Hydrological dataset), is based on (1) a probabilistic precipitation, temperature, and reference evapotranspiration downscaling of the Twentieth Century Reanalysis over France, called SCOPE Climate, and (2) continuous hydrological modelling using SCOPE Climate as forcings over the whole period. This work then introduces tools for defining spatio-temporal extreme low-flow events. Extreme low-flow events are first locally defined through the sequent peak algorithm using a novel combination of a fixed threshold and a daily variable threshold. A dedicated spatial matching procedure is then established to identify spatio-temporal events across France. This procedure is furthermore adapted to the SCOPE Hydro 25-member ensemble to characterize in a probabilistic way unrecorded historical events at the national scale. Extreme low-flow events are described and compared in a spatially and temporally homogeneous way over 140 years on a large set of catchments. Results highlight well-known recent events like 1976 or 1989-1990, but also older and relatively forgotten ones like the 1878 and 1893 events. These results contribute to improving our knowledge of historical events and provide a selection of benchmark events for climate change adaptation purposes. Moreover, this study allows for further detailed analyses of the effect of climate variability and anthropogenic climate change on low-flow hydrology at the scale of France.

  16. 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.

  17. A non-equilibrium model for soil heating and moisture transport during extreme surface heating

    Directory of Open Access Journals (Sweden)

    W. J. Massman

    2015-03-01

    Full Text Available With increasing use of prescribed fire by land managers and increasing likelihood of wildfires due to climate change comes the need to improve modeling capability of extreme heating of soils during fires. This issue is addressed here by developing a one-dimensional non-equilibrium model of soil evaporation and transport of heat, soil moisture, and water vapor, for use with surface forcing ranging from daily solar cycles to extreme conditions encountered during fires. The model employs a linearized Crank–Nicolson scheme for the conservation equations of energy and mass and its performance is evaluated against dynamic soil temperature and moisture observations obtained during laboratory experiments on soil samples exposed to surface heat fluxes ranging between 10 000 and 50 000 W m−2. The Hertz–Knudsen equation is the basis for constructing the model's non-equilibrium evaporative source term. The model includes a dynamic residual soil moisture as a function of temperature and soil water potential, which allows the model to capture some of the dynamic aspects of the strongly bound soil moisture that seems to require temperatures well beyond 150 °C to fully evaporate. Furthermore, the model emulates the observed increase in soil moisture ahead of the drying front and the hiatus in the soil temperature rise during the strongly evaporative stage of drying. It also captures the observed rapid evaporation of soil moisture that occurs at relatively low temperatures (50–90 °C. Sensitivity analyses indicate that the model's success results primarily from the use of a temperature and moisture potential dependent condensation coefficient in the evaporative source term. The model's solution for water vapor density (and vapor pressure, which can exceed one standard atmosphere, cannot be experimentally verified, but they are supported by results from (earlier and very different models developed for somewhat different purposes and for different porous

  18. Uncertainties Related to Extreme Event Statistics of Sewer System Surcharge and Overflow

    DEFF Research Database (Denmark)

    Schaarup-Jensen, Kjeld; Johansen, C.; Thorndahl, Søren Liedtke

    2005-01-01

    by performing long term simulations - using a sewer flow simulation model - and draw up extreme event statistics from the model simulations. In this context it is important to realize that uncertainties related to the input parameters of rainfall runoff models will give rise to uncertainties related...... to draw up extreme event statistics covering return periods of as much as 33 years. By comparing these two different extreme event statistics it is evident that these to a great extent depend on the uncertainties related to the input parameters of the rainfall runoff model....... proceeding in an acceptable manner, if flooding of these levels is having an average return period bigger than a predefined value. This practice is also often used in functional analysis of existing sewer systems. If a sewer system can fulfil recommended flooding frequencies or not, can only be verified...

  19. Extreme events induced by self-action of laser beams in dynamic nonlinear liquid crystal cells

    Science.gov (United States)

    Bugaychuk, S.; Iljin, A.; Chunikhina, K.

    2017-06-01

    Optical extreme events represent a feature of nonlinear systems where there may emerge individual pulses possessing very high (or very low) intensity hardly probable statistically. Such property is being connected with the generation of solitons in the nonlinear systems. We carry out the first experiments for detection of extreme events during two-wave mixing with nonlinear dynamical liquid crystal (LC) cells. We investigate the statistics of the extreme events in dependence on relation between the duration of a laser pulse and the time characteristic of dynamic grating relaxation in LC cell. Our research shows that the self-diffraction of laser beams with a dynamical grating support the generation of envelope solitons in this system.

  20. Representation of extreme precipitation events in Nepal in CMIP5 models

    Science.gov (United States)

    Jung, Woosung; Ryu, Byeong; Yun, Myong

    2016-04-01

    Nepal is highly vulnerable to of extreme climate events due in part to its mountainous terrain and lack of infrastructure. Climate change is projected to increase the frequency and magnitude of extreme temperature and precipitation events worldwide, with particularly severe impacts likely in Nepal. In this study we analyze the performance of general circulation models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) at simulating temperature and precipitation in Nepal relative to the NCEP Reanalysis II and observational data, and we project how extreme events may change during the 21st century. We analyze the uncertainty in our projections, and compare the current generation of models in CMIP5 to prior results in this region using older climate models. Finally, we consider the impact of our projections on Nepal's society and economy.

  1. Army Corps of Engineers: Efforts to Assess the Impact of Extreme Weather Events

    Science.gov (United States)

    2015-07-01

    southern California dam, which allowed the Corps to retain rainwater to help respond to the state’s extreme drought conditions . The Corps has assessed...anticipate, prepare for, respond to, and adapt to changing conditions and to withstand and recover rapidly from disruptions with minimal damage. As directed... Extreme Weather Events in the Planning Process Page 16 GAO-15-660 Army Corps of Engineers adapting projects to this projected change.27

  2. Research on Trends in Extreme Weather Events and their Effects on Grapevine in Romanian Viticulture

    OpenAIRE

    Georgeta Mihaela Bucur; Anca Cristina Babes

    2016-01-01

    The aim of this work was to investigate the frequency and intensity of extreme weather events in various centers from Romania’s viticultural regions: winter frost, extreme temperatures during the growing season and summer droughts. Winter frost damaging the vine is a significant risk to grape production, mainly in the plains and lowlands to the foothills. The frequency of winter frost damaging the vine has increased during the last decades, in the context of climate change. Also, there has be...

  3. Trend in frequency of extreme precipitation events over Ontario from ensembles of multiple GCMs

    Science.gov (United States)

    Deng, Ziwang; Qiu, Xin; Liu, Jinliang; Madras, Neal; Wang, Xiaogang; Zhu, Huaiping

    2016-05-01

    As one of the most important extreme weather event types, extreme precipitation events have significant impacts on human and natural environment. This study assesses the projected long term trends in frequency of occurrence of extreme precipitation events represented by heavy precipitation days, very heavy precipitation days, very wet days and extreme wet days over Ontario, based on results of 21 CMIP3 GCM runs. To achieve this goal, first, all model data are linearly interpolated onto 682 grid points (0.45° × 0.45°) in Ontario; Next, biases in model daily precipitation amount are corrected with a local intensity scaling method to make the total wet days and total wet day precipitation from each of the GCMs are consistent with that from the climate forecast system reanalysis data, and then the four indices are estimated for each of the 21 GCM runs for 1968-2000, 2046-2065 and 2081-2100. After that, with the assumption that the rate parameter of the Poisson process for the occurrence of extreme precipitation events may vary with time as climate changes, the Poisson regression model which expresses the log rate as a linear function of time is used to detect the trend in frequency of extreme events in the GCMs simulations; Finally, the trends and their uncertainty are estimated. The result shows that in the twenty-first century annual heavy precipitation days, very heavy precipitation days and very wet days and extreme wet days are likely to significantly increase over major parts of Ontario and particularly heavy precipitation days, very wet days are very likely to significantly increase in some sub-regions in eastern Ontario. However, trends of seasonal indices are not significant.

  4. Extreme Events and Disaster Risk Reduction - a Future Earth KAN initiative

    Science.gov (United States)

    Frank, Dorothea; Reichstein, Markus

    2017-04-01

    The topic of Extreme Events in the context of global environmental change is both a scientifically challenging and exciting topic, and of very high societal relevance. The Future Earth Cluster initiative E3S organized in 2016 a cross-community/co-design workshop on Extreme Events and Environments from Climate to Society (http://www.e3s-future-earth.eu/index.php/ConferencesEvents/ConferencesAmpEvents). Based on the results, co-design research strategies and established network of the workshop, and previous activities, E3S is thriving to establish the basis for a longer-term research effort under the umbrella of Future Earth. These led to an initiative for a Future Earth Knowledge Action Network on Extreme Events and Disaster Risk Reduction. Example initial key question in this context include: What are meaningful indices to describe and quantify impact-relevant (e.g. climate) extremes? Which system properties yield resistance and resilience to extreme conditions? What are the key interactions between global urbanization processes, extreme events, and social and infrastructure vulnerability and resilience? The long-term goal of this KAN is to contribute to enhancing the resistance, resilience, and adaptive capacity of socio-ecological systems across spatial, temporal and institutional scales, in particular in the light of hazards affected by ongoing environmental change (e.g. climate change, global urbanization and land use/land cover change). This can be achieved by enhanced understanding, prediction, improved and open data and knowledge bases for detection and early warning decision making, and by new insights on natural and societal conditions and governance for resilience and adaptive capacity.

  5. Extreme events: being prepared for the pitfalls with progressing sustainable urban water management.

    Science.gov (United States)

    Keath, N A; Brown, R R

    2009-01-01

    It is widely accepted that new, more sustainable approaches to urban water management are required if cities and ecosystems are to become resilient to the effects of growing urban populations and global warming. Climate change predictions show that it is likely that cities around the world will be subject to an increasing number of extreme and less predictable events including flooding and drought. Historical transition studies have shown that major events such as extremes can expedite the adoption of new practices by destabilising existing management regimes and opening up new windows of opportunity for change. Yet, they can also act to reinforce and further entrench old practices. This case study of two Australian cities responding to extreme water scarcity reveals that being unprepared for extremes can undermine progress towards sustainable outcomes. The results showed that despite evidence of significant progress towards sustainable urban water management in Brisbane and Melbourne, the extreme water scarcity acted to reinforce traditional practices at the expense of emerging sustainability niches. Drawing upon empirical research and transitions literature, recommendations are provided for developing institutional mechanisms that are able to respond proactively to extreme events and be a catalyst for SUWM when such opportunities for change arise.

  6. Estimating return periods for daily precipitation extreme events over the Brazilian Amazon

    Science.gov (United States)

    Santos, Eliane Barbosa; Lucio, Paulo Sérgio; Santos e Silva, Cláudio Moisés

    2016-11-01

    This paper aims to model the occurrence of daily precipitation extreme events and to estimate the return period of these events through the extreme value theory (generalized extreme value distribution (GEV) and the generalized Pareto distribution (GPD)). The GEV and GPD were applied in precipitation series of homogeneous regions of the Brazilian Amazon. The GEV and GPD goodness of fit were evaluated by quantile-quantile (Q-Q) plot and by the application of the Kolmogorov-Smirnov (KS) test, which compares the cumulated empirical distributions with the theoretical ones. The Q-Q plot suggests that the probability distributions of the studied series are appropriated, and these results were confirmed by the KS test, which demonstrates that the tested distributions have a good fit in all sub-regions of Amazon, thus adequate to study the daily precipitation extreme event. For all return levels studied, more intense precipitation extremes is expected to occur within the South sub-regions and the coastal area of the Brazilian Amazon. The results possibly will have some practical application in local extreme weather forecast.

  7. 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.

  8. Extreme climatic events in relation to global change and their impact on life histories

    Institute of Scientific and Technical Information of China (English)

    Juan MORENO; Anders Pape Mφller

    2011-01-01

    Extreme weather conditions occur at an increasing rate as evidenced by higher frequency of hurricanes and more extreme precipitation and temperature anomalies. Such extreme environmental conditions will have important implications for all living organisms through greater frequency of reproductive failure and reduced adult survival. We review examples of reproductive failure and reduced survival related to extreme weather conditions. Phenotypic plasticity may not be sufficient to allow adaptation to extreme weather for many animals. Theory predicts reduced reproductive effort as a response to increased stochasticity. We predict that patterns of natural selection will change towards truncation selection as environmental conditions become more extreme. Such changes in patterns of selection may facilitate adaptation to extreme events. However, effects of selection on reproductive effort are difficult to detect. We present a number of predictions for the effects of extreme weather conditions in need of empirical tests. Finally, we suggest a number of empirical reviews that could improve our ability to judge the effects of extreme environmental conditions on life history.

  9. Extreme climatic events in relation to global change and their impact on life histories

    Directory of Open Access Journals (Sweden)

    Juan MORENO, Anders Pape Møller

    2011-06-01

    Full Text Available Extreme weather conditions occur at an increasing rate as evidenced by higher frequency of hurricanes and more extreme precipitation and temperature anomalies. Such extreme environmental conditions will have important implications for all living organisms through greater frequency of reproductive failure and reduced adult survival. We review examples of reproductive failure and reduced survival related to extreme weather conditions. Phenotypic plasticity may not be sufficient to allow adaptation to extreme weather for many animals. Theory predicts reduced reproductive effort as a response to increased stochasticity. We predict that patterns of natural selection will change towards truncation selection as environmental conditions become more extreme. Such changes in patterns of selection may facilitate adaptation to extreme events. However, effects of selection on reproductive effort are difficult to detect. We present a number of predictions for the effects of extreme weather conditions in need of empirical tests. Finally, we suggest a number of empirical reviews that could improve our ability to judge the effects of extreme environmental conditions on life history [Current Zoology 57 (3: 375–389, 2011].

  10. Formation of extreme surface turbulent heat fluxes from the ocean to the atmosphere in the North Atlantic

    Science.gov (United States)

    Tilinina, N. D.; Gulev, S. K.; Gavrikov, A. V.

    2016-01-01

    The role of extreme surface turbulent fluxes in total oceanic heat loss in the North Atlantic is studied. The atmospheric circulation patterns enhancing ocean-atmosphere heat flux in regions with significant contributions of the extreme heat fluxes (up to 60% of the net heat loss) are analyzed. It is shown that extreme heat fluxes in the Gulf Stream and the Greenland and Labrador Seas occur in zones with maximal air pressure gradients, i.e., in cyclone-anticyclone interaction zones.

  11. Defining extreme GIC event scenarios: why and how to meet the power engineering needs?

    Science.gov (United States)

    Pulkkinen, A. A.

    2016-12-01

    The latest developments in terms of the US Federal Energy Regulatory Commission standards process and National Space Weather Action Plan have increased the pressure on the scientific community to develop reasonable extreme GIC event benchmarks and scenarios. At the same time, scientists and power engineerings have established robust communications that now allow passage of actionable information between the two communities. Consequently, it is now possible to describe and tailor the extreme event scenarios to meet the power engineering analysis requirements. Tailoring of the scenarios is critically important for the power engineers to be able to use the information provided by the scientific community. In this presentation, by reviewing the power transmission system impact mechanisms and engineering analyses flow, we present our current understanding of what actually is needed from the power engineering perspective to carry out extreme storm assessments. We hope that this information will help the scientific community to develop extreme event information that is directly actionable on the end-user side. We also review some of our recent work to develop extreme event information that meets the engineering needs. Some of this work was carried out in support of the FERC/NERC GMD standards development process.

  12. Developing a concept of social-ecological-technological systems to characterize resilience of urban areas and infrastructure to extreme events

    Science.gov (United States)

    Chester, M.; Grimm, N. B.; Redman, C.; Miller, T.; McPherson, T.; Munoz-Erickson, T.; Chandler, D. G.

    2015-12-01

    Climate change is widely considered one of the greatest challenges to global sustainability, with extreme events being the most immediate way that people experience this phenomenon. Urban areas are particularly vulnerable to these events given their location, concentration of people, and increasingly complex and interdependent infrastructure. We are developing a conceptual framework for urban social-ecological-technological systems (SETS) that will allow researchers and practitioners to assess how infrastructure can be resilient, provide ecosystem services, improve social well being, and exploit new technologies in ways that benefit urban populations. The framework integrates the three domains of social and equity issues, environmental quality and protection, and technical/engineering aspects, to form a concept of infrastructure that occurs at the intersection of the domains. Examples show how the more common socioecological systems and socially sensitive engineering approaches that fail to incorporate the third dimension may elevate vulnerability to climate-related disaster. The SETS conceptual framework bridges currently siloed social science, environmental science, and engineering approaches to significantly advance research into the structure, function, and emergent properties of SETS. Extreme events like heat waves in Phoenix; coastal and urban flooding in the wake of superstorm Sandy and following hurricanes in Miami, FL; drought in Mexico; and urban flooding in Baltimore, Portland, San Juan PR, Syracuse, and Valdivia, Chile provide examples of the impacts of and vulnerability to extreme events that demand a new approach. The infrastructure of the future must be resilient, leverage ecosystem services, improve social well being, and exploit new technologies in ways that benefit all segments of urban populations and are appropriate to the particular urban contexts. These contexts are defined not only by the biophysical environment but also by culture and

  13. Historical deforestation increased the risk of heat extremes in northern mid-latitudes

    Science.gov (United States)

    Lejeune, Quentin; Davin, Edouard; Gudmundsson, Lukas; Winckler, Johannes; Seneviratne, Sonia

    2017-04-01

    During the industrial period, large areas in the world have experienced a reduction in forest cover and an expansion of agricultural areas. Some modelling studies showed that this has significantly affected the intensity of temperature extremes through changes in biophysical land surface properties (Christidis et al. 2013, Pitman et al. 2012), however they exhibit a low level of agreement about its overall climate impact. Besides, even if they generally point toward an albedo-induced cooling over deforested mid-latitudes, this does not align with recent observational evidence suggesting that deforestation has a local daytime warming effect, especially in summer (Lee et al. 2011). Here, for the first time we intend to constrain CMIP5 models with observations in order to assess the contribution of historical deforestation to changes in the risk of warm extreme events. To do so, we have selected five models from the CMIP5 ensemble that can reproduce the observed local warming effect of deforestation during daytime in summer. Our results indicate that deforestation played a primary role in the evolution of hot extremes since preindustrial time. We quantify that a decrease in tree cover by at least 15% locally increased the intensity of the 99th percentile of daily maximum temperature (corresponding to the 3-4 hottest days of the year) by 0.6°C over northern mid-latitudes, accounting for 30-40% of their total warming. Moreover, it amplified the increase in their frequency due to the greenhouse gas forcing by 30%. Our results imply that land-cover changes need to be considered when studying past and future changes in heat extremes, in particular for regional-scale detection and attribution purposes. References: Christidis, N., P. A. Stott, G. C. Hegerl, and R. A. Betts, The role of land use change in the recent warming of daily extreme temperatures (2013), Geophysical Research Letters, 40, 589-594 Pitman, A. J., et al., Effects of land cover change on temperature and

  14. Towards a unified study of extreme events using universality concepts and transdisciplinary analysis methods

    Science.gov (United States)

    Balasis, George; Donner, Reik V.; Donges, Jonathan F.; Radebach, Alexander; Eftaxias, Konstantinos; Kurths, Jürgen

    2013-04-01

    The dynamics of many complex systems is characterized by the same universal principles. In particular, systems which are otherwise quite different in nature show striking similarities in their behavior near tipping points (bifurcations, phase transitions, sudden regime shifts) and associated extreme events. Such critical phenomena are frequently found in diverse fields such as climate, seismology, or financial markets. Notably, the observed similarities include a high degree of organization, persistent behavior, and accelerated energy release, which are common to (among others) phenomena related to geomagnetic variability of the terrestrial magnetosphere (intense magnetic storms), seismic activity (electromagnetic emissions prior to earthquakes), solar-terrestrial physics (solar flares), neurophysiology (epileptic seizures), and socioeconomic systems (stock market crashes). It is an open question whether the spatial and temporal complexity associated with extreme events arises from the system's structural organization (geometry) or from the chaotic behavior inherent to the nonlinear equations governing the dynamics of these phenomena. On the one hand, the presence of scaling laws associated with earthquakes and geomagnetic disturbances suggests understanding these events as generalized phase transitions similar to nucleation and critical phenomena in thermal and magnetic systems. On the other hand, because of the structural organization of the systems (e.g., as complex networks) the associated spatial geometry and/or topology of interactions plays a fundamental role in the emergence of extreme events. Here, a few aspects of the interplay between geometry and dynamics (critical phase transitions) that could result in the emergence of extreme events, which is an open problem, will be discussed.

  15. Star formation in extreme environments : The effects of cosmic rays and mechanical heating

    NARCIS (Netherlands)

    Meijerink, R.; Spaans, M.; Loenen, A. F.; van der Werf, Paul P.

    Context. The molecular interstellar medium in extreme environments, such as Arp 220, but also NGC 253 appears to have extremely high cosmic ray (CR) rates (10(3)-10(4) x Milky Way) and substantial mechanical heating from supernova driven turbulence. Aims. We explore the consequences of high CR rates

  16. On Predictive Understanding of Extreme Events: Pattern Recognition Approach; Prediction Algorithms; Applications to Disaster Preparedness

    Science.gov (United States)

    Keilis-Borok, V. I.; Soloviev, A.; Gabrielov, A.

    2011-12-01

    We describe a uniform approach to predicting different extreme events, also known as critical phenomena, disasters, or crises. The following types of such events are considered: strong earthquakes; economic recessions (their onset and termination); surges of unemployment; surges of crime; and electoral changes of the governing party. A uniform approach is possible due to the common feature of these events: each of them is generated by a certain hierarchical dissipative complex system. After a coarse-graining, such systems exhibit regular behavior patterns; we look among them for "premonitory patterns" that signal the approach of an extreme event. We introduce methodology, based on the optimal control theory, assisting disaster management in choosing optimal set of disaster preparedness measures undertaken in response to a prediction. Predictions with their currently realistic (limited) accuracy do allow preventing a considerable part of the damage by a hierarchy of preparedness measures. Accuracy of prediction should be known, but not necessarily high.

  17. A Numerical Approach for Hybrid Simulation of Power System Dynamics Considering Extreme Icing Events

    DEFF Research Database (Denmark)

    Chen, Lizheng; Zhang, Hengxu; Wu, Qiuwei

    2017-01-01

    The global climate change leads to more extreme meteorological conditions such as icing weather, which have caused great losses to power systems. Comprehensive simulation tools are required to enhance the capability of power system risk assessment under extreme weather conditions. A hybrid...... numerical simulation scheme integrating icing weather events with power system dynamics is proposed to extend power system numerical simulation. A technique is developed to efficiently simulate the interaction of slow dynamics of weather events and fast dynamics of power systems. An extended package for PSS....../E enabling hybrid simulation of icing event and power system disturbance is developed, based on which a hybrid simulation platform is established. Numerical studies show that the functionality of power system simulation is greatly extended by taking into account the icing weather events....

  18. Experimental characterization of extreme events of inertial dissipation in a turbulent swirling flow

    Science.gov (United States)

    Saw, E.-W.; Kuzzay, D.; Faranda, D.; Guittonneau, A.; Daviaud, F.; Wiertel-Gasquet, C.; Padilla, V.; Dubrulle, B.

    2016-08-01

    The three-dimensional incompressible Navier-Stokes equations, which describe the motion of many fluids, are the cornerstones of many physical and engineering sciences. However, it is still unclear whether they are mathematically well posed, that is, whether their solutions remain regular over time or develop singularities. Even though it was shown that singularities, if exist, could only be rare events, they may induce additional energy dissipation by inertial means. Here, using measurements at the dissipative scale of an axisymmetric turbulent flow, we report estimates of such inertial energy dissipation and identify local events of extreme values. We characterize the topology of these extreme events and identify several main types. Most of them appear as fronts separating regions of distinct velocities, whereas events corresponding to focusing spirals, jets and cusps are also found. Our results highlight the non-triviality of turbulent flows at sub-Kolmogorov scales as possible footprints of singularities of the Navier-Stokes equation.

  19. 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...

  20. 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...

  1. BOLIVAR-tool for analysis and simulation of metocean extreme events

    Science.gov (United States)

    Lopatoukhin, Leonid; Boukhanovsky, Alexander

    2015-04-01

    Metocean extreme events are caused by the combination of multivariate and multiscale processes which depend from each other in different scales (due to short-term, synoptic, annual, year-to-year variability). There is no simple method for their estimation with controllable tolerance. Thus, the extreme analysis in practice is sometimes reduced to the exploration of various methods and models in respect to decreasing the uncertainty of estimates. Therefore, a researcher needs the multifaceted computational tools which cover the various branches of extreme analysis. BOLIVAR is the multi-functional computational software for the researches and engineers who explore the extreme environmental conditions to design and build offshore structures and floating objects. It contains a set of computational modules of various methods for extreme analysis, and a set of modules for the stochastic and hydrodynamic simulation of metocean processes. In this sense BOLIVAR is a Problem Solving Environment (PSE). The BOLIVAR is designed for extreme events analysis and contains a set of computational modules of IDM, AMS, POT, MENU, and SINTEF methods, and a set of modules for stochastic simulation of metocean processes in various scales. The BOLIVAR is the tool to simplify the resource-consuming computational experiments to explore the metocean extremes in univariate and multivariate cases. There are field ARMA models for short-term variability, spatial-temporal random pulse model for synoptic variability (storms and calms alteration), cyclostationare model of annual and year-to-year variability. The combination of above mentioned modules and data sources allows to estimate: omnidirectional and directional extremes (with T-years return periods); multivariate extremes (the set of parameters) and evaluation of their impacts to marine structures and floating objects; extremes of spatial-temporal fields (including the trajectory of T-years storms). An employment of concurrent methods for

  2. Risk from drought and extreme heat in Russian wheat production and its relation to atmospheric blocking and teleconnection patterns

    Science.gov (United States)

    Giannakaki, Paraskevi; Calanca, Pierluigi

    2017-04-01

    Russia has become one of the leading wheat exporters worldwide. Major breakdowns in Russian wheat production induced by extreme weather events are therefore of high significance not only for the domestic but also for the global market. Wheat production in south-western Russia, the main growing area, suffers in particular from the adverse effects of drought and heat waves. For this reason knowledge of the occurrence of this type of extreme events and of the processes that lead to adverse conditions is of paramount importance for risk management. The negative impacts of heat waves and drought are particularly severe when anomalous conditions persist in time. As an example, a blocking event in summer 2010 resulted in one of the warmest and worst drought conditions in Russia's recent history. The latter caused a decline in Russian wheat production by more than 30%, which in turn prompted the Russian government to issue an export ban that lasted until summer 2011. In view of this, the question of course arises of how much of the negative variations in Russian wheat production levels can be explained by blocking events and other features of the large-scale atmospheric circulation. Specific questions are: how often are blocking events over Russia associated with extreme high temperatures and dry conditions? Which of the teleconnection patterns are correlated with drought and heat stress conditions in the area? Answering these questions can contribute to a develop strategies for agricultural risk management. In this contribution we present results of a study that aims at characterizing the occurrence of adverse weather conditions in south-western Russia in relation to atmospheric blocking and teleconnection patterns such as East Atlantic/Western Russia pattern, the Polar/Eurasia pattern, the North Atlantic Oscillation and the Scandinavia pattern. The analysis relies on weather data for 1980-2014 from 130 stations distributed across the wheat production area. The account

  3. METHOD TO ASSESS THE EXTREME HYDROLOGICAL EVENTS IN DANUBE FLUVIAL DELTA

    Directory of Open Access Journals (Sweden)

    MARIAN MIERLĂ

    2012-03-01

    Full Text Available Method to assess the extreme hydrological events in Danube fluvial Delta. In this paper the subject is about of testing a method for Romania to assess the extreme hydrological events. In this paper through hydrological extreme events it should be understood as the extreme droughts and the extreme flooding. The place to be tested this method for Romania is the Danube Delta, fluvial delta to be more precisely. The importance of the area consists in the fact that is the third Delta of the Europe (after the Volga’s and Kuban’s. The method that is supposed to be tested on a specific part of the delta is aiming to rise the knowledge about the extreme hydrological events (drought and flooding and to be able to respond in an appropriate way to these. For this paper it will be taken into account the hydrological events occurred in 2003 (the exceptional drought and in 2006 (the exceptional flood. To do the analysis there were used satellite images (LANDSAT from the period that was taken into account and additional there were used the hypsometrical model of the Danube Delta for the specific area. The first two datasets (2003 and 2006 satellite images give information about were the border of the water (in drought period and respective in flooding one reached. The second dataset (the delta’s hypsometry give information about the altitude of the terrain in order to establish which areas, at a certain water level, are flooded. The result of these datasets combination is the calibration of the hypsometrical model of the Danube Delta, in that region, regarding the hydrological events in the sense of building-up the hydrograds as isolines. The new approach of this matter can be more concrete and makes easier to see on the cartographic support the hydrologic events. The information obtained from these datasets makes the awareness regarding the extreme hydrological events to be higher and respective the measures taken to mitigate these will be more efficient.

  4. Erosion during extreme flood events dominates Holocene canyon evolution in northeast Iceland.

    Science.gov (United States)

    Baynes, Edwin R C; Attal, Mikaël; Niedermann, Samuel; Kirstein, Linda A; Dugmore, Andrew J; Naylor, Mark

    2015-02-24

    Extreme flood events have the potential to cause catastrophic landscape change in short periods of time (10(0) to 10(3) h). However, their impacts are rarely considered in studies of long-term landscape evolution (>10(3) y), because the mechanisms of erosion during such floods are poorly constrained. Here we use topographic analysis and cosmogenic (3)He surface exposure dating of fluvially sculpted surfaces to determine the impact of extreme flood events within the Jökulsárgljúfur canyon (northeast Iceland) and to constrain the mechanisms of bedrock erosion during these events. Surface exposure ages allow identification of three periods of intense canyon cutting about 9 ka ago, 5 ka ago, and 2 ka ago during which multiple large knickpoints retreated large distances (>2 km). During these events, a threshold flow depth was exceeded, leading to the toppling and transportation of basalt lava columns. Despite continuing and comparatively large-scale (500 m(3)/s) discharge of sediment-rich glacial meltwater, there is no evidence for a transition to an abrasion-dominated erosion regime since the last erosive event because the vertical knickpoints have not diffused over time. We provide a model for the evolution of the Jökulsárgljúfur canyon through the reconstruction of the river profile and canyon morphology at different stages over the last 9 ka and highlight the dominant role played by extreme flood events in the shaping of this landscape during the Holocene.

  5. Local instability driving extreme events in a pair of coupled chaotic electronic circuits

    Science.gov (United States)

    de Oliveira, Gilson F.; Di Lorenzo, Orlando; de Silans, Thierry Passerat; Chevrollier, Martine; Oriá, Marcos; Cavalcante, Hugo L. D. de Souza

    2016-06-01

    For a long time, extreme events happening in complex systems, such as financial markets, earthquakes, and neurological networks, were thought to follow power-law size distributions. More recently, evidence suggests that in many systems the largest and rarest events differ from the other ones. They are dragon kings, outliers that make the distribution deviate from a power law in the tail. Understanding the processes of formation of extreme events and what circumstances lead to dragon kings or to a power-law distribution is an open question and it is a very important one to assess whether extreme events will occur too often in a specific system. In the particular system studied in this paper, we show that the rate of occurrence of dragon kings is controlled by the value of a parameter. The system under study here is composed of two nearly identical chaotic oscillators which fail to remain in a permanently synchronized state when coupled. We analyze the statistics of the desynchronization events in this specific example of two coupled chaotic electronic circuits and find that modifying a parameter associated to the local instability responsible for the loss of synchronization reduces the occurrence of dragon kings, while preserving the power-law distribution of small- to intermediate-size events with the same scaling exponent. Our results support the hypothesis that the dragon kings are caused by local instabilities in the phase space.

  6. Extreme sea events during the last millennium in the northeast of Morocco

    Science.gov (United States)

    Raji, O.; Dezileau, L.; Von Grafenstein, U.; Niazi, S.; Snoussi, M.; Martinez, P.

    2015-02-01

    The Moroccan Mediterranean coast is located in one of the area's most vulnerable to extreme weather events or tsunami hazards. The objective of this research is to reconstruct the historical extreme submersion-event record using sea-induced deposits preserved in coastal lagoon. The Nador lagoon is the largest Moroccan lagoon (115 km2). It is located along the western Mediterranean, which has a high cyclogenetic character and is exposed to tsunamis from the Alboran Sea. The sandy barrier which separates the lagoon from the Mediterranean Sea is marked by much overwash, which indicate how intensely it has been exposed to the adverse sea events through history. Using the UWITEC© gravity coring platform, an undisturbed MC4.5 core (1.15 m long) was successfully sampled in the studied lagoon. To identify extreme sea events, a multi-proxy approach was applied combining sedimentological and geochemical data. Three paleoevents were identified; all of them are concentrated over the last 500 years, and the most recent event corresponds to the 1889 storm. For the others deposits, it is difficult to determine exactly their origin; however, the high frequency of storm events over the relevant period and the absence of historical tsunamis evidence is more in favor of the meteorological origin.

  7. Proactive modeling of water quality impacts of extreme precipitation events in a drinking water reservoir.

    Science.gov (United States)

    Jeznach, Lillian C; Hagemann, Mark; Park, Mi-Hyun; Tobiason, John E

    2017-10-01

    Extreme precipitation events are of concern to managers of drinking water sources because these occurrences can affect both water supply quantity and quality. However, little is known about how these low probability events impact organic matter and nutrient loads to surface water sources and how these loads may impact raw water quality. This study describes a method for evaluating the sensitivity of a water body of interest from watershed input simulations under extreme precipitation events. An example application of the method is illustrated using the Wachusett Reservoir, an oligo-mesotrophic surface water reservoir in central Massachusetts and a major drinking water supply to metropolitan Boston. Extreme precipitation event simulations during the spring and summer resulted in total organic carbon, UV-254 (a surrogate measurement for reactive organic matter), and total algae concentrations at the drinking water intake that exceeded recorded maximums. Nutrient concentrations after storm events were less likely to exceed recorded historical maximums. For this particular reservoir, increasing inter-reservoir transfers of water with lower organic matter content after a large precipitation event has been shown in practice and in model simulations to decrease organic matter levels at the drinking water intake, therefore decreasing treatment associated oxidant demand, energy for UV disinfection, and the potential for formation of disinfection byproducts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Climate change, extreme events and increased risk of salmonellosis in Maryland, USA: Evidence for coastal vulnerability.

    Science.gov (United States)

    Jiang, Chengsheng; Shaw, Kristi S; Upperman, Crystal R; Blythe, David; Mitchell, Clifford; Murtugudde, Raghu; Sapkota, Amy R; Sapkota, Amir

    2015-10-01

    Salmonella is a leading cause of acute gastroenteritis worldwide. Patterns of salmonellosis have been linked to weather events. However, there is a dearth of data regarding the association between extreme events and risk of salmonellosis, and how this risk may disproportionately impact coastal communities. We obtained Salmonella case data from the Maryland Foodborne Diseases Active Surveillance Network (2002-2012), and weather data from the National Climatic Data Center (1960-2012). We developed exposure metrics related to extreme temperature and precipitation events using a 30 year baseline (1960-1989) and linked them with county-level salmonellosis data. Data were analyzed using negative binomial Generalized Estimating Equations. We observed a 4.1% increase in salmonellosis risk associated with a 1 unit increase in extreme temperature events (incidence rate ratio (IRR):1.041; 95% confidence interval (CI):1.013-1.069). This increase in risk was more pronounced in coastal versus non-coastal areas (5.1% vs 1.5%). Likewise, we observed a 5.6% increase in salmonellosis risk (IRR:1.056; CI:1.035-1.078) associated with a 1 unit increase in extreme precipitation events, with the impact disproportionately felt in coastal areas (7.1% vs 3.6%). To our knowledge, this is the first empirical evidence showing that extreme temperature/precipitation events-that are expected to be more frequent and intense in coming decades-are disproportionately impacting coastal communities with regard to salmonellosis. Adaptation strategies need to account for this differential burden, particularly in light of ever increasing coastal populations. Copyright © 2015. Published by Elsevier Ltd.

  9. Extreme Heat: A Prevention Guide to Promote Your Personal Health and Safety

    Science.gov (United States)

    ... Part 3 of 3) Hot Weather Tips Heat Stress in Older Adults FAQs Extreme Heat PSAs Related Links MMWR Bibliography CDC's Program Floods Flood Readiness Personal Hygiene After a Disaster Cleanup of Flood Water After a Flood Worker Safety Educational Materials Floods ...

  10. 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

  11. Impacts of extreme heat and drought on crop yields in China: an assessment by using the DLEM-AG2 model

    Science.gov (United States)

    Zhang, J.; Yang, J.; Pan, S.; Tian, H.

    2016-12-01

    China is not only one of the major agricultural production countries with the largest population in the world, but it is also the most susceptible to climate change and extreme events. Much concern has been raised about how extreme climate has affected crop yield, which is crucial for China's food supply security. However, the quantitative assessment of extreme heat and drought impacts on crop yield in China has rarely been investigated. By using the Dynamic Land Ecosystem Model (DLEM-AG2), a highly integrated process-based ecosystem model with crop-specific simulation, here we quantified spatial and temporal patterns of extreme climatic heat and drought stress and their impacts on the yields of major food crops (rice, wheat, maize, and soybean) across China during 1981-2015, and further investigated the underlying mechanisms. Simulated results showed that extreme heat and drought stress significantly reduced national cereal production and increased the yield gaps between potential yield and rain-fed yield. The drought stress was the primary factor to reduce crop yields in the semi-arid and arid regions, and extreme heat stress slightly aggravated the yield loss. The yield gap between potential yield and rain-fed yield was larger at locations with lower precipitation. Our results suggest that a large exploitable yield gap in response to extreme climatic heat-drought stress offers an opportunity to increase productivity in China by optimizing agronomic practices, such as irrigation, fertilizer use, sowing density, and sowing date.

  12. Model design for predicting extreme precipitation event impacts on water quality in a water supply reservoir

    Science.gov (United States)

    Hagemann, M.; Jeznach, L. C.; Park, M. H.; Tobiason, J. E.

    2016-12-01

    Extreme precipitation events such as tropical storms and hurricanes are by their nature rare, yet have disproportionate and adverse effects on surface water quality. In the context of drinking water reservoirs, common concerns of such events include increased erosion and sediment transport and influx of natural organic matter and nutrients. As part of an effort to model the effects of an extreme precipitation event on water quality at the reservoir intake of a major municipal water system, this study sought to estimate extreme-event watershed responses including streamflow and exports of nutrients and organic matter for use as inputs to a 2-D hydrodynamic and water quality reservoir model. Since extreme-event watershed exports are highly uncertain, we characterized and propagated predictive uncertainty using a quasi-Monte Carlo approach to generate reservoir model inputs. Three storm precipitation depths—corresponding to recurrence intervals of 5, 50, and 100 years—were converted to streamflow in each of 9 tributaries by volumetrically scaling 2 storm hydrographs from the historical record. Rating-curve models for concentratoin, calibrated using 10 years of data for each of 5 constituents, were then used to estimate the parameters of a multivariate lognormal probability model of constituent concentrations, conditional on each scenario's storm date and streamflow. A quasi-random Halton sequence (n = 100) was drawn from the conditional distribution for each event scenario, and used to generate input files to a calibrated CE-QUAL-W2 reservoir model. The resulting simulated concentrations at the reservoir's drinking water intake constitute a low-discrepancy sample from the estimated uncertainty space of extreme-event source water-quality. Limiting factors to the suitability of this approach include poorly constrained relationships between hydrology and constituent concentrations, a high-dimensional space from which to generate inputs, and relatively long run

  13. Observing Episodic Coronal Heating Events Rooted in Chromospheric Activity

    CERN Document Server

    McIntosh, Scott W

    2009-01-01

    We present results of a multi-wavelength study of episodic plasma injection into the corona of AR 10942. We exploit long-exposure images of the Hinode and Transition Region and Coronal Explorer (TRACE) spacecraft to study the properties of faint, episodic, "blobs" of plasma that are propelled upward along coronal loops that are rooted in the AR plage. We find that the source location and characteristic velocities of these episodic upflow events match those expected from recent spectroscopic observations of faint coronal upflows that are associated with upper chromospheric activity, in the form of highly dynamic spicules. The analysis presented ties together observations from coronal and chromospheric spectrographs and imagers, providing more evidence of the connection of discrete coronal mass heating and injection events with their source, dynamic spicules, in the chromosphere.

  14. Forest operations, extreme flooding events, and considerations for hydrologic modeling in the Appalachians--A review

    Science.gov (United States)

    M.A. Eisenbies; W.M. Aust; J.A. Burger; M.B. Adams

    2007-01-01

    The connection between forests and water resources is well established, but the relationships among controlling factors are only partly understood. Concern over the effects of forestry operations, particularly harvesting, on extreme flooding events is a recurrent issue in forest and watershed management. Due to the complexity of the system, and the cost of installing...

  15. Ultimate design load analysis of planetary gearbox bearings under extreme events

    DEFF Research Database (Denmark)

    Gallego Calderon, Juan Felipe; Natarajan, Anand; Cutululis, Nicolaos Antonio

    2017-01-01

    This paper investigates the impact of extreme events on the planet bearings of a 5 MW gearbox. The system is simulated using an aeroelastic tool, where the turbine structure is modeled, and MATLAB/Simulink, where the drivetrain (gearbox and generator) are modeled using a lumped-parameter approach...

  16. Magnetic storms and solar flares: can be analysed within similar mathematical framework with other extreme events?

    Science.gov (United States)

    Balasis, Georgios; Potirakis, Stelios M.; Papadimitriou, Constantinos; Zitis, Pavlos I.; Eftaxias, Konstantinos

    2015-04-01

    The field of study of complex systems considers that the dynamics of complex systems are founded on universal principles that may be used to describe a great variety of scientific and technological approaches of different types of natural, artificial, and social systems. We apply concepts of the nonextensive statistical physics, on time-series data of observable manifestations of the underlying complex processes ending up to different extreme events, in order to support the suggestion that a dynamical analogy characterizes the generation of a single magnetic storm, solar flare, earthquake (in terms of pre-seismic electromagnetic signals) , epileptic seizure, and economic crisis. The analysis reveals that all the above mentioned different extreme events can be analyzed within similar mathematical framework. More precisely, we show that the populations of magnitudes of fluctuations included in all the above mentioned pulse-like-type time series follow the traditional Gutenberg-Richter law as well as a nonextensive model for earthquake dynamics, with similar nonextensive q-parameter values. Moreover, based on a multidisciplinary statistical analysis we show that the extreme events are characterized by crucial common symptoms, namely: (i) high organization, high compressibility, low complexity, high information content; (ii) strong persistency; and (iii) existence of clear preferred direction of emerged activities. These symptoms clearly discriminate the appearance of the extreme events under study from the corresponding background noise.

  17. A spatial and nonstationary model for the frequency of extreme rainfall events

    DEFF Research Database (Denmark)

    Gregersen, Ida Bülow; Madsen, Henrik; Rosbjerg, Dan;

    2013-01-01

    Changes in the properties of extreme rainfall events have been observed worldwide. In relation to the discussion of ongoing climatic changes, it is of high importance to attribute these changes to known sources of climate variability. Focusing on spatial and temporal changes in the frequency...... of extreme rainfall events, a statistical model is tested for this purpose. The model is built on the theory of generalized linear models and uses Poisson regression solved by generalized estimation equations. Spatial and temporal explanatory variables can be included simultaneously, and their relative...... importance can be assessed. Additionally, the model allows for a spatial correlation between the measurements. Data from a Danish rain gauge network are used as a case study for model evaluation. Focusing on 10 min and 24 h rainfall extremes, it was found that regional variation in the mean annual...

  18. Solar Energetic Particle Event Associated with the 2012 July 23 Extreme Solar Storm

    CERN Document Server

    Zhu, Bei; Luhmann, Janet G; Hu, Huidong; Wang, Rui; Yang, Zhongwei

    2016-01-01

    We study the solar energetic particle (SEP) event associated with the 2012 July 23 extreme solar storm, for which STEREO and the spacecraft at L1 provide multi-point remote sensing and in situ observations. The extreme solar storm, with a superfast shock and extremely enhanced ejecta magnetic fields observed near 1 AU at STEREO A, was caused by the combination of successive coronal mass ejections (CMEs). Meanwhile, energetic particles were observed by STEREO and near-Earth spacecraft such as ACE and SOHO, suggestive of a wide longitudinal spread of the particles at 1 AU. Combining the SEP observations with in situ plasma and magnetic field measurements we investigate the longitudinal distribution of the SEP event in connection with the associated shock and CMEs. Our results underscore the complex magnetic configuration of the inner heliosphere formed by solar eruptions. The examinations of particle intensities, proton anisotropy distributions, element abundance ratios, magnetic connectivity and spectra also g...

  19. The Challenges from Extreme Climate Events for Sustainable Development in Amazonia: the Acre State Experience

    Science.gov (United States)

    Araújo, M. D. N. M.

    2015-12-01

    In the past ten years Acre State, located in Brazil´s southwestern Amazonia, has confronted sequential and severe extreme events in the form of droughts and floods. In particular, the droughts and forest fires of 2005 and 2010, the 2012 flood within Acre, the 2014 flood of the Madeira River which isolated Acre for two months from southern Brazil, and the most severe flooding throughout the state in 2015 shook the resilience of Acrean society. The accumulated costs of these events since 2005 have exceeded 300 million dollars. For the last 17 years, successive state administrations have been implementing a socio-environmental model of development that strives to link sustainable economic production with environmental conservation, particularly for small communities. In this context, extreme climate events have interfered significantly with this model, increasing the risks of failure. The impacts caused by these events on development in the state have been exacerbated by: a) limitations in monitoring; b) extreme events outside of Acre territory (Madeira River Flood) affecting transportation systems; c) absence of reliable information for decision-making; and d) bureaucratic and judicial impediments. Our experience in these events have led to the following needs for scientific input to reduce the risk of disasters: 1) better monitoring and forecasting of deforestation, fires, and hydro-meteorological variables; 2) ways to increase risk perception in communities; 3) approaches to involve more effectively local and regional populations in the response to disasters; 4) more accurate measurements of the economic and social damages caused by these disasters. We must improve adaptation to and mitigation of current and future extreme climate events and implement a robust civil defense, adequate to these new challenges.

  20. Food Security and Extreme Events: Evidence from Smallholder Farmers in Central America

    Science.gov (United States)

    Saborio-Rodriguez, M.; Alpizar, F.; Harvey, C.; Martinez, R.; Vignola, R.; Viguera, B.; Capitan, T.

    2016-12-01

    Extreme weather events, which are expected to increase in magnitude and frequency due to climate change, are one of the main threats for smallholder farmers in Central America. Using a rich dataset from carefully selected subsistence farm households, we explore the determinants and severity of food insecurity resulting from extreme hydrometeorological hazards. In addition, we analyze farmerś coping strategies. Our analysis sheds light over food insecurity as an expression of vulnerability in a region that is expected to be increasingly exposed to extreme events and in a population already stressed by poverty and lack of opportunities. Regarding food insecurity, multivariate analyses indicate that education, having at least one migrant in the household, labor allocation, number of plots, and producing coffee are determinants of the probability of experiencing lack of food after an extreme weather event. Once the household is lacking food, the duration of the episode is related to access to credit, number of plots, producing coffee, ownership of land and gender of the head of the household. This results are in line with previous literature on the determinants of food insecurity in particular, and vulnerability, in general. Our dataset also allows us to analyze coping strategies. Households experiencing lack of food after an extreme weather event report mainly changes in their habits, as decreasing the amount of food consumed (54%) and modifying their diet (35%). A low proportion of household (between 10% and 15%, depending on the nature of the event) use their assets, by redirecting their savings, migrating, and selling items from the house. Asking money or food from family and friends or from an organization is reported for 4% of the households. This general results are connected to the specific coping strategies related to damages in crops, which are explored in detail. Our results indicate that there are patterns among the household experiencing lack of food

  1. Spatial and temporal analysis of extreme sea level and storm surge events around the coastline of the UK.

    Science.gov (United States)

    Haigh, Ivan D; Wadey, Matthew P; Wahl, Thomas; Ozsoy, Ozgun; Nicholls, Robert J; Brown, Jennifer M; Horsburgh, Kevin; Gouldby, Ben

    2016-12-06

    In this paper we analyse the spatial footprint and temporal clustering of extreme sea level and skew surge events around the UK coast over the last 100 years (1915-2014). The vast majority of the extreme sea level events are generated by moderate, rather than extreme skew surges, combined with spring astronomical high tides. We distinguish four broad categories of spatial footprints of events and the distinct storm tracks that generated them. There have been rare events when extreme levels have occurred along two unconnected coastal regions during the same storm. The events that occur in closest succession (coastline. The spring/neap tidal cycle prevents successive extreme sea level events from happening within 4-8 days. Finally, the 2013/14 season was highly unusual in the context of the last 100 years from an extreme sea level perspective.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. Vulnerability assessment of Central-East Sardinia (Italy to extreme rainfall events

    Directory of Open Access Journals (Sweden)

    A. Bodini

    2010-01-01

    Full Text Available In Sardinia (Italy, the highest frequency of extreme events is recorded in the Central-East area (3–4 events per year. The presence of high and steep mountains near the sea on the central and south-eastern coast, causes an East-West precipitation gradient in autumn especially, due to hot and moist currents coming from Africa. Soil structure and utilization make this area highly vulnerable to flash flooding and landslides. The specific purpose of this work is to provide a description of the heavy rainfall phenomenon on a statistical basis. The analysis mainly focuses on i the existence of trends in heavy rainfall and ii the characterization of the distribution of extreme events. First, to study possible trends in extreme events a few indices have been analyzed by the linear regression test. The analysis has been carried out at annual and seasonal scales. Then, extreme values analysis has been carried out by fitting a Generalized Pareto Distribution (GPD to the data. As far as trends are concerned, different results are obtained at the two temporal scales: significant trends are obtained at the seasonal scale which are masked at the annual scale. By combining trend analysis and GPD analysis, the vulnerability of the study area to the occurrence of heavy rainfall has been characterized. Therefore, this work might support the improvement of land use planning and the application of suitable prevention systems. Future work will consider the extension of the analysis to all Sardinia and the application of statistical methods taking into account the spatial correlation of extreme events.

  7. Vulnerability assessment of Central-East Sardinia (Italy) to extreme rainfall events

    Science.gov (United States)

    Bodini, A.; Cossu, Q. A.

    2010-01-01

    In Sardinia (Italy), the highest frequency of extreme events is recorded in the Central-East area (3-4 events per year). The presence of high and steep mountains near the sea on the central and south-eastern coast, causes an East-West precipitation gradient in autumn especially, due to hot and moist currents coming from Africa. Soil structure and utilization make this area highly vulnerable to flash flooding and landslides. The specific purpose of this work is to provide a description of the heavy rainfall phenomenon on a statistical basis. The analysis mainly focuses on i) the existence of trends in heavy rainfall and ii) the characterization of the distribution of extreme events. First, to study possible trends in extreme events a few indices have been analyzed by the linear regression test. The analysis has been carried out at annual and seasonal scales. Then, extreme values analysis has been carried out by fitting a Generalized Pareto Distribution (GPD) to the data. As far as trends are concerned, different results are obtained at the two temporal scales: significant trends are obtained at the seasonal scale which are masked at the annual scale. By combining trend analysis and GPD analysis, the vulnerability of the study area to the occurrence of heavy rainfall has been characterized. Therefore, this work might support the improvement of land use planning and the application of suitable prevention systems. Future work will consider the extension of the analysis to all Sardinia and the application of statistical methods taking into account the spatial correlation of extreme events.

  8. Subsurface signatures and timing of extreme wave events along the southeast Indian coast

    Indian Academy of Sciences (India)

    Rajesh R Nair; Madhav K Murari; C S Vijaya Lakshmi; Ilya Buynevich; Ron J Goble; P Srinivasan; S G N Murthy; Deshraj Trivedi; Suresh Chandra Kandpal; S M Hussain; D Sengupta; Ashok K Singhvi

    2011-10-01

    Written history’s limitation becomes apparent when attempting to document the predecessors of extreme coastal events in the Indian Ocean, from 550–700 years in Thailand and 1000 years in Indonesia. Detailed ground-penetrating radar (GPR) surveys in Mahabalipuram, southeast India, complemented with sedimentological analyses, magnetic susceptibility measurements, and optical dating provide strong evidence of extreme wave events during the past 3700 years. The diagnostic event signatures include the extent and elevation of the deposits, as well as morphologic similarity of buried erosional scarps to those reported in northern Sumatra region. Optical ages immediately overlying the imaged discontinuities that coincides with high concentration of heavy minerals date the erosional events to 340 ± 35, 350 ± 20, 490 ± 30, 880 ± 40, 1080 ± 60, 1175 ± 188, 2193 ± 266, 2235 ± 881, 2489 ± 293, 2450 ± 130, 2585 ± 609, 3710 ± 200 years ago. These evidences are crucial in reconstructing paleo extreme wave events and will pave the way for regional correlation of erosional horizons along the northern margin of Indian Ocean.

  9. Extreme dissipation event due to plume collision in a turbulent convection cell

    CERN Document Server

    Schumacher, Joerg

    2016-01-01

    An extreme dissipation event in the bulk of a closed three-dimensional turbulent convection cell is found to be correlated with a strong reduction of the large-scale circulation flow in the system that happens at the same time as a plume emission event from the bottom plate. The reduction in the large-scale circulation opens the possibility for a nearly frontal collision of down- and upwelling plumes and the generation of a high-amplitude thermal dissipation layer in the bulk. This collision is locally connected to a subsequent high-amplitude energy dissipation event in the form of a strong shear layer. Our analysis illustrates the impact of transitions in the large-scale structures on extreme events at the smallest scales of the turbulence, a direct link that is observed in a flow with boundary layers. We also show that detection of extreme dissipation events which determine the far-tail statistics of the dissipation fields in the bulk requires long-time integrations of the equations of motion over at least ...

  10. Sea extreme events during the last millennium in north-east of Morocco

    Science.gov (United States)

    Raji, O.; Dezileau, L.; Von Grafenstein, U.; Niazi, S.; Snoussi, M.; Martinez, P.

    2014-03-01

    The Moroccan Mediterranean coast is located in one of the most vulnerable area to extreme weather events or tsunami hazards. The objective of this research is to reconstruct the historical extreme submersion-events record using sea-induced deposits preserved in coastal lagoon. The Nador lagoon is the largest Moroccan lagoon (115 km2) located along the Western Mediterranean which presents a high cyclogenetic character and is exposed to tsunamis from Alboran Sea. The sandy barrier which separates the lagoon from the Mediterranean Sea is marked by many overwashes, which indicate how intensely has been exposed to the adverse sea events through history. Using the UWITEC coring platform, an undisturbed MC4.5 core (1.15 m long) was successfully sampled in the studied lagoon. To identify sea extreme events, a multi-proxy approach was applied combining sedimentogical and geochemical data. The preliminary results show that the identified paleo-events are concentrated over the last 500 years. The challenge that remains now is to distinguish between the tsunami and the storm deposits.

  11. Sea extreme events during the last millennium in north-east of Morocco

    Directory of Open Access Journals (Sweden)

    O. Raji

    2014-03-01

    Full Text Available The Moroccan Mediterranean coast is located in one of the most vulnerable area to extreme weather events or tsunami hazards. The objective of this research is to reconstruct the historical extreme submersion-events record using sea-induced deposits preserved in coastal lagoon. The Nador lagoon is the largest Moroccan lagoon (115 km2 located along the Western Mediterranean which presents a high cyclogenetic character and is exposed to tsunamis from Alboran Sea. The sandy barrier which separates the lagoon from the Mediterranean Sea is marked by many overwashes, which indicate how intensely has been exposed to the adverse sea events through history. Using the UWITEC coring platform, an undisturbed MC4.5 core (1.15 m long was successfully sampled in the studied lagoon. To identify sea extreme events, a multi-proxy approach was applied combining sedimentogical and geochemical data. The preliminary results show that the identified paleo-events are concentrated over the last 500 years. The challenge that remains now is to distinguish between the tsunami and the storm deposits.

  12. Extreme dissipation event due to plume collision in a turbulent convection cell

    Science.gov (United States)

    Schumacher, Jörg; Scheel, Janet D.

    2016-10-01

    An extreme dissipation event in the bulk of a closed three-dimensional turbulent convection cell is found to be correlated with a strong reduction of the large-scale circulation flow in the system that happens at the same time as a plume emission event from the bottom plate. The reduction in the large-scale circulation opens the possibility for a nearly frontal collision of down- and upwelling plumes and the generation of a high-amplitude thermal dissipation layer in the bulk. This collision is locally connected to a subsequent high-amplitude energy dissipation event in the form of a strong shear layer. Our analysis illustrates the impact of transitions in the large-scale structures on extreme events at the smallest scales of the turbulence, a direct link that is observed in a flow with boundary layers. We also show that detection of extreme dissipation events which determine the far-tail statistics of the dissipation fields in the bulk requires long-time integrations of the equations of motion over at least a hundred convective time units.

  13. Extreme Rainfall Events and Associated Natural Hazards in Alaknanda Valley, Indian Himalayan Region

    Institute of Scientific and Technical Information of China (English)

    JOSHI Varun; KUMAR Kireet

    2006-01-01

    Entire Himalayan region is vulnerable to rain-induced (torrential rainfall) hazards in the form of flash flood, cloudburst or glacial lake outburst flood. Flash floods and cloudburst are generally caused by high intensity rainfall followed by debris flow or landslide often resulting into blockade of river channels. The examples of some major disasters caused by torrential rainfall events in last fifty years are the flash floods of 1968 in Teesta valley, in 1993 and 20o0 in Sntlej valley, in 1978 in Bhagirathi and in 197o in Alaknanda river valleys. The formation of landslide dams and subsequent breaching is also associated with such rainfall events. These dams may persist for years or may burst within a short span of its formation. Due to sudden surge of water level in the river valleys, havoc and panic are created in the down stream. In Alaknanda valley, frequencies of such extreme rainfall events are found to be increasing in last two decades. However, the monthly trend of extreme rainfall events has partly indicated this increase. In most of the years extreme rainfall events and cloudburst disaster were reported in August during the later part of the monsoon season.

  14. Large Scale Influences on Drought and Extreme Precipitation Events in the United States

    Science.gov (United States)

    Collow, A.; Bosilovich, M. G.; Koster, R. D.; Eichmann, A.

    2015-12-01

    Observations indicate that extreme weather events are increasing and it is likely that this trend will continue through the 21st century. However, there is uncertainty and disagreement in recent literature regarding the mechanisms by which extreme temperature and precipitation events are increasing, including the suggestion that enhanced Arctic warming has resulted in an increase in blocking events and a more meridional flow. A steady gradual increase in heavy precipitation events has been observed in the Midwestern and Northeastern United States, while the Southwestern United States, particularly California, has experienced suppressed precipitation and an increase in consecutive dry days over the past few years. The frequency, intensity, and duration of heavy precipitation events in the Midwestern United States and Northeastern United States, as well as drought in the Southwestern United States are examined using the Modern Era Retrospective Analysis for Research and Applications Version-2 (MERRA-2). Indices developed by the Expert Team on Climate Change Detection and Indices representing drought and heavy precipitation events have been calculated using the MERRA-2 dataset for the period of 1980 through 2014. Trends in these indices are analyzed and the indices are compared to large scale circulations and climate modes using a composite and statistical linkages approach. Statistically significant correlations are present in the summer months between heavy precipitation events and meridional flow despite the lack of enhanced Arctic warming, contradicting the suggested mechanisms. Weaker, though still significant, correlations are observed in the winter months when the Arctic is warming more rapidly than the Midlatitudes.

  15. Vulnerability to extreme-heat-associated hospitalization in three counties in Michigan, USA, 2000-2009

    Science.gov (United States)

    Ogbomo, Adesuwa S.; Gronlund, Carina J.; O'Neill, Marie S.; Konen, Tess; Cameron, Lorraine; Wahl, Robert

    2017-05-01

    With climate change, extreme heat (EH) events are increasing, so it is important to understand who is vulnerable to heat-associated morbidity. We determined the association between EH and hospitalizations for all natural causes; cardiovascular, respiratory, and renal diseases; diabetes mellitus; and acute myocardial infarction in Michigan, USA, at different intensities and durations. We assessed confounding by ozone and how individual characteristics and health insurance payer (a proxy for income) modified these associations. We obtained Michigan Inpatient Database, National Climatic Data Center, and US Environmental Protection Agency ozone data for May-September, 2000-2009 for three Michigan counties. We employed a case-crossover design and modeled EH as an indicator for temperature above the 95th, 97th, or 99th percentile thresholds for 1, 2, 3, or 4 days. We examined effect modification by patient age, race, sex, and health insurance payer and pooled the county results. Among non-whites, the pooled odds ratio for hospitalization on EH (97th percentile threshold) vs. non-EH days for renal diseases was 1.37 (95 % CI = 1.13-1.66), which increased with increasing EH intensity, but was null among whites (OR = 1.00, 95 % CI = 0.81, 1.25). We observed a null association between EH and cardiovascular hospitalization. EH (99th percentile threshold) was associated with myocardial infarction hospitalizations. Confounding by ozone was minimal. EH was associated with hospitalizations for renal disease among non-whites. This information on vulnerability to heat-associated morbidity helps characterize the public health burden of EH and target interventions including patient education.

  16. Vulnerability to extreme-heat-associated hospitalization in three counties in Michigan, USA, 2000-2009

    Science.gov (United States)

    Ogbomo, Adesuwa S.; Gronlund, Carina J.; O'Neill, Marie S.; Konen, Tess; Cameron, Lorraine; Wahl, Robert

    2016-10-01

    With climate change, extreme heat (EH) events are increasing, so it is important to understand who is vulnerable to heat-associated morbidity. We determined the association between EH and hospitalizations for all natural causes; cardiovascular, respiratory, and renal diseases; diabetes mellitus; and acute myocardial infarction in Michigan, USA, at different intensities and durations. We assessed confounding by ozone and how individual characteristics and health insurance payer (a proxy for income) modified these associations. We obtained Michigan Inpatient Database, National Climatic Data Center, and US Environmental Protection Agency ozone data for May-September, 2000-2009 for three Michigan counties. We employed a case-crossover design and modeled EH as an indicator for temperature above the 95th, 97th, or 99th percentile thresholds for 1, 2, 3, or 4 days. We examined effect modification by patient age, race, sex, and health insurance payer and pooled the county results. Among non-whites, the pooled odds ratio for hospitalization on EH (97th percentile threshold) vs. non-EH days for renal diseases was 1.37 (95 % CI = 1.13-1.66), which increased with increasing EH intensity, but was null among whites (OR = 1.00, 95 % CI = 0.81, 1.25). We observed a null association between EH and cardiovascular hospitalization. EH (99th percentile threshold) was associated with myocardial infarction hospitalizations. Confounding by ozone was minimal. EH was associated with hospitalizations for renal disease among non-whites. This information on vulnerability to heat-associated morbidity helps characterize the public health burden of EH and target interventions including patient education.

  17. Impacts of urban growth and heat waves events on the urban heat island in Bucharest city

    Science.gov (United States)

    Zoran, Maria A.; Savastru, Roxana S.; Savastru, Dan M.; Dida, Adrian I.

    2016-10-01

    This study investigated the influences of urban growth and heat waves events on Urban Heat Island in relationship with several biophysical variables in Bucharest metropolitan area of Romania through satellite and in-situ monitoring data. Remote sensing data from Landsat TM/ETM+ and time series MODIS Terra/Aqua sensors have been used to assess urban land cover- temperature interactions over period between 2000 and 2016 years. Vegetation abundances and percent impervious surfaces were derived by means of linear spectral mixture model, and a method for effectively enhancing impervious surface has been developed to accurately examine the urban growth. The land surface temperature (Ts), a key parameter for urban thermal characteristics analysis, was also analyzed in relation with the Normalized Difference Vegetation Index (NDVI) at city level. Based on these parameters, the urban growth, urban heat island effect (UHI) and the relationships of Ts to other biophysical parameters (surface albedo, precipitations, wind intensity and direction) have been analyzed. Results show that in the metropolitan area ratio of impervious surface in Bucharest increased significantly during investigated period, the intensity of urban heat island and heat wave events being most significant. The correlation analyses revealed that, at the pixel-scale, Ts possessed a strong positive correlation with percent impervious surfaces and negative correlation with vegetation abundances at the regional scale, respectively. This analysis provided an integrated research scheme and the findings can be very useful for urban ecosystem modeling.

  18. Terrestrial Laser Scanner (TLS) as a tool for the reconstruction of extreme wave event characteristics

    Science.gov (United States)

    Schneider, Bastian; Hoffmann, Gösta

    2017-04-01

    The shores of the Northern Indian Ocean were exposed to extreme wave inundation in the past. Two relevant hazards, storm surges triggered by tropical cyclones and tsunamis, are known to occur in the region but are rarely instrumentally recorded. Various sediment deposits along the coast are the only remnants of those past events. A profound understanding of return periods and magnitudes of past events is essential for developing land-use planning and risk mitigation measures in Oman and neighboring countries. A detailed investigation of these deposits, in this case primarily blocks and boulder trains but also fine grained sediments, provides insight on parameters such as wave height and inundation distance. These parameters can then be used for modeling inundation scenarios superimposed on modern infrastructure. We are investigating the spatial 3D-distribution of the extreme wave event sediments along the coastline through a high-precision survey of the event deposits using a Faro Focus 3D X330 TLS. A TLS is capable of recording high-detail and colored point clouds, which allows detailed measurements and has proved to be a powerful tool in geosciences. These multi-parameter point clouds in combination with dating results serve as a base for extreme wave event return period and magnitude estimations. Relevant parameters on large sediments are size, shape, volume, mass as well as relative arrangement, sorting and orientation. Furthermore, the TLS data is used to distinguish between the various boulder lithologies using a multi-scale supervised classification. Surface roughness as a result of weathering can serve as an indicator for exposure time of boulders and hint on various generations of extreme wave events. The distribution of the boulders relative to the site they were quarried from indicates on the flow direction of the waves and consequently might help to distinguish between storm and tsunami waves.

  19. AP1000{sup R} design robustness against extreme external events - Seismic, flooding, and aircraft crash

    Energy Technology Data Exchange (ETDEWEB)

    Pfister, A.; Goossen, C.; Coogler, K.; Gorgemans, J. [Westinghouse Electric Company LLC, 1000 Westinghouse Drive, Cranberry Township, PA 16066 (United States)

    2012-07-01

    Both the International Atomic Energy Agency (IAEA) and the U.S. Nuclear Regulatory Commission (NRC) require existing and new nuclear power plants to conduct plant assessments to demonstrate the unit's ability to withstand external hazards. The events that occurred at the Fukushima-Dai-ichi nuclear power station demonstrated the importance of designing a nuclear power plant with the ability to protect the plant against extreme external hazards. The innovative design of the AP1000{sup R} nuclear power plant provides unparalleled protection against catastrophic external events which can lead to extensive infrastructure damage and place the plant in an extended abnormal situation. The AP1000 plant is an 1100-MWe pressurized water reactor with passive safety features and extensive plant simplifications that enhance construction, operation, maintenance and safety. The plant's compact safety related footprint and protection provided by its robust nuclear island structures prevent significant damage to systems, structures, and components required to safely shutdown the plant and maintain core and spent fuel pool cooling and containment integrity following extreme external events. The AP1000 nuclear power plant has been extensively analyzed and reviewed to demonstrate that it's nuclear island design and plant layout provide protection against both design basis and extreme beyond design basis external hazards such as extreme seismic events, external flooding that exceeds the maximum probable flood limit, and malicious aircraft impact. The AP1000 nuclear power plant uses fail safe passive features to mitigate design basis accidents. The passive safety systems are designed to function without safety-grade support systems (such as AC power, component cooling water, service water, compressed air or HVAC). The plant has been designed to protect systems, structures, and components critical to placing the reactor in a safe shutdown condition within the steel

  20. Global and regional changes in exposure to extreme heat and the relative contributions of climate and population change

    Science.gov (United States)

    Liu, Zhao; Anderson, Bruce; Yan, Kai; Dong, Weihua; Liao, Hua; Shi, Peijun

    2017-03-01

    The frequency and intensity of extreme heat wave events have increased in the past several decades and are likely to continue to increase in the future under the influence of human-induced climate change. Exposure refers to people, property, systems, or other elements present in hazard zones that are thereby subject to potential losses. Exposure to extreme heat and changes therein are not just determined by climate changes but also population changes. Here we analyze output for three scenarios of greenhouse gas emissions and socio-economic growth to estimate future exposure change taking account of both climate and population factors. We find that for the higher emission scenario (RCP8.5-SSP3), the global exposure increases nearly 30-fold by 2100. The average exposure for Africa is over 118 times greater than it has been historically, while the exposure for Europe increases by only a factor of four. Importantly, in the absence of climate change, exposure is reduced by 75–95% globally and across all geographic regions, as compared with exposure under the high emission scenario. Under lower emission scenarios RCP4.5-SSP2 and RCP2.6-SSP1, the global exposure is reduced by 65% and 85% respectively, highlighting the efficacy of mitigation efforts in reducing exposure to extreme heat.

  1. Global and regional changes in exposure to extreme heat and the relative contributions of climate and population change.

    Science.gov (United States)

    Liu, Zhao; Anderson, Bruce; Yan, Kai; Dong, Weihua; Liao, Hua; Shi, Peijun

    2017-03-07

    The frequency and intensity of extreme heat wave events have increased in the past several decades and are likely to continue to increase in the future under the influence of human-induced climate change. Exposure refers to people, property, systems, or other elements present in hazard zones that are thereby subject to potential losses. Exposure to extreme heat and changes therein are not just determined by climate changes but also population changes. Here we analyze output for three scenarios of greenhouse gas emissions and socio-economic growth to estimate future exposure change taking account of both climate and population factors. We find that for the higher emission scenario (RCP8.5-SSP3), the global exposure increases nearly 30-fold by 2100. The average exposure for Africa is over 118 times greater than it has been historically, while the exposure for Europe increases by only a factor of four. Importantly, in the absence of climate change, exposure is reduced by 75-95% globally and across all geographic regions, as compared with exposure under the high emission scenario. Under lower emission scenarios RCP4.5-SSP2 and RCP2.6-SSP1, the global exposure is reduced by 65% and 85% respectively, highlighting the efficacy of mitigation efforts in reducing exposure to extreme heat.

  2. 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.

  3. 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.

  4. Establishing a Numerical Modeling Framework for Hydrologic Engineering Analyses of Extreme Storm Events

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiaodong; Hossain, Faisal; Leung, L. Ruby

    2017-08-01

    In this study a numerical modeling framework for simulating extreme storm events was established using the Weather Research and Forecasting (WRF) model. Such a framework is necessary for the derivation of engineering parameters such as probable maximum precipitation that are the cornerstone of large water management infrastructure design. Here this framework was built based on a heavy storm that occurred in Nashville (USA) in 2010, and verified using two other extreme storms. To achieve the optimal setup, several combinations of model resolutions, initial/boundary conditions (IC/BC), cloud microphysics and cumulus parameterization schemes were evaluated using multiple metrics of precipitation characteristics. The evaluation suggests that WRF is most sensitive to IC/BC option. Simulation generally benefits from finer resolutions up to 5 km. At the 15km level, NCEP2 IC/BC produces better results, while NAM IC/BC performs best at the 5km level. Recommended model configuration from this study is: NAM or NCEP2 IC/BC (depending on data availability), 15km or 15km-5km nested grids, Morrison microphysics and Kain-Fritsch cumulus schemes. Validation of the optimal framework suggests that these options are good starting choices for modeling extreme events similar to the test cases. This optimal framework is proposed in response to emerging engineering demands of extreme storm events forecasting and analyses for design, operations and risk assessment of large water infrastructures.

  5. The Definition and Classification of Extensive and Persistent Extreme Cold Events in China

    Institute of Scientific and Technical Information of China (English)

    PENG Jing-Bei; BUEH Cholaw

    2011-01-01

    Using the observed daily temperatures from 756 stations in China during the period from 1951 to 2009, extensive and persistent extreme cold events (EPECEs) were defined according to the following three steps: 1) a station was defined as an extreme cold station (ECS) if the observed temperature was lower than its 10th percentile threshold; 2) an extensive extreme cold event was determined to be present if the approximated area occupied by the ECSs was more than 10% of the total area of China (83rd percentile) on its starting day and the maximum area occupied by the ECSs was at least 20% of the total area of China (96th percentile); and 3) an EPECE was determined to be present if the extensive extreme cold event lasted for at least for eight days. 52 EPECEs were identified in this manner, and these identification results were also verified using other reliable data. On the basis of cluster analysis, five types of EPECEs were classified according to the spatial distribution of ECSs at their most extensive time over the course of the EPECE.

  6. Mathematical aspects of assessing extreme events for the safety of nuclear plants

    Science.gov (United States)

    Potempski, Slawomir; Borysiewicz, Mieczyslaw

    2015-04-01

    In the paper the review of mathematical methodologies applied for assessing low frequencies of rare natural events like earthquakes, tsunamis, hurricanes or tornadoes, floods (in particular flash floods and surge storms), lightning, solar flares, etc., will be given in the perspective of the safety assessment of nuclear plants. The statistical methods are usually based on the extreme value theory, which deals with the analysis of extreme deviation from the median (or the mean). In this respect application of various mathematical tools can be useful, like: the extreme value theorem of Fisher-Tippett-Gnedenko leading to possible choices of general extreme value distributions, or the Pickands-Balkema-de Haan theorem for tail fitting, or the methods related to large deviation theory. In the paper the most important stochastic distributions relevant for performing rare events statistical analysis will be presented. This concerns, for example, the analysis of the data with the annual extreme values (maxima - "Annual Maxima Series" or minima), or the peak values, exceeding given thresholds at some periods of interest ("Peak Over Threshold"), or the estimation of the size of exceedance. Despite of the fact that there is a lack of sufficient statistical data directly containing rare events, in some cases it is still possible to extract useful information from existing larger data sets. As an example one can consider some data sets available from the web sites for floods, earthquakes or generally natural hazards. Some aspects of such data sets will be also presented taking into account their usefulness for the practical assessment of risk for nuclear power plants coming from extreme weather conditions.

  7. 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

  8. Nitrogen accumulation and partitioning in a High Arctic tundra ecosystem from extreme atmospheric N deposition events.

    Science.gov (United States)

    Choudhary, Sonal; Blaud, Aimeric; Osborn, A Mark; Press, Malcolm C; Phoenix, Gareth K

    2016-06-01

    Arctic ecosystems are threatened by pollution from recently detected extreme atmospheric nitrogen (N) deposition events in which up to 90% of the annual N deposition can occur in just a few days. We undertook the first assessment of the fate of N from extreme deposition in High Arctic tundra and are presenting the results from the whole ecosystem (15)N labelling experiment. In 2010, we simulated N depositions at rates of 0, 0.04, 0.4 and 1.2 g Nm(-2)yr(-1), applied as (15)NH4(15)NO3 in Svalbard (79(°)N), during the summer. Separate applications of (15)NO3(-) and (15)NH4(+) were also made to determine the importance of N form in their retention. More than 95% of the total (15)N applied was recovered after one growing season (~90% after two), demonstrating a considerable capacity of Arctic tundra to retain N from these deposition events. Important sinks for the deposited N, regardless of its application rate or form, were non-vascular plants>vascular plants>organic soil>litter>mineral soil, suggesting that non-vascular plants could be the primary component of this ecosystem to undergo measurable changes due to N enrichment from extreme deposition events. Substantial retention of N by soil microbial biomass (70% and 39% of (15)N in organic and mineral horizon, respectively) during the initial partitioning demonstrated their capacity to act as effective buffers for N leaching. Between the two N forms, vascular plants (Salix polaris) in particular showed difference in their N recovery, incorporating four times greater (15)NO3(-) than (15)NH4(+), suggesting deposition rich in nitrate will impact them more. Overall, these findings show that despite the deposition rates being extreme in statistical terms, biologically they do not exceed the capacity of tundra to sequester pollutant N during the growing season. Therefore, current and future extreme events may represent a major source of eutrophication.

  9. The impacts of '05.6' extreme flood event on riverine carbon fluxes in Xijiang River

    Institute of Scientific and Technical Information of China (English)

    SUN HuiGuo; HAN JingTai; ZHANG ShuRong; LU XiXi

    2007-01-01

    An extreme flood event with a frequency of nearly 200 year occurred in June of 2005 in the Xijiang River,the main trunk stream of the Zhujiang River. Samples were systematically collected during the flood event, and water quality parameters, including total suspended sediment (TSS), dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and particulate organic carbon (POC) were analyzed,and riverine carbon concentrations associated with its changing pattern through the flood process were discussed. These parameters reflect the changes in basin surface flow and subsurface flow during the flood. This flood event influenced annual flux estimations of POC, DOC, and DIC to great extents.Based on carbon flux estimations for the year 2005 and the flood event (June 21-28) in the Xijiang River, it was found that DIC, DOC, and POC fluxes during '05.6' flood event are 1.52x106 g.km-2.a-1,0.24x106 g.km-2.a-1, and 0.54x106 g.km-2.a-1, and account for 14.87%, 24.75% and 44.89% of the annual fluxes in 2005, respectively. The results suggested that carbon exports during extreme flood events had great contributions to the total carbon fluxes and composition of various carbon components, being important for accurate estimates of annual carbon fluxes in rivers with frequent floods.

  10. 'The plunger hypothesis' - predicting the tropospheric impact of extreme stratospheric events

    Science.gov (United States)

    Clark, Simon; Baldwin, Mark; Stephenson, David

    2016-04-01

    The coupling of events in the polar stratosphere to those in the polar troposphere is not currently understood. Extreme events in the stratosphere have been identified to have a lasting influence on the tropospheric circulation below for a period of up to 60 days. As such understanding the downward propagation of stratospheric circulation anomalies would be beneficial to surface forecasting. In this work we use the new 'plunger hypothesis', that mass fluxes into and out of the polar region compress the polar column of air - in a manner similar to a plunger - and cause pressure and temperature anomalies. We demonstrate how a quasigeostrophic assumption within this hypothesis allows for the prediction of mass fluxes across the boundary to the polar region given the pressure distribution at the boundary. This then allows for a prediction of how a given stratospheric event such as a sudden stratospheric warming (SSW) or a strong vortex event influences the polar troposphere. The performance of this hypothesis is tested; its usefulness in improving surface forecasts, its accuracy in response to stratospheric events, and its ability to predict downward propagation of Arctic Oscillation (AO) index in the aftermath of extreme stratospheric events. The link between this work and the PV inversion formulation of stratosphere-troposphere coupling is discussed. This work forms part of a three and a half year PhD project.

  11. A multigap resistive plate chamber array for the Extreme Energy Events project

    Science.gov (United States)

    De Gruttola, D.; Abbrescia, M.; Agocs, A.; Aiola, S.; Antolini, R.; Avanzini, C.; Baldini Ferroli, R.; Bencivenni, G.; Bossini, E.; Bressan, E.; Chiavassa, A.; Cicalò, C.; Cifarelli, L.; Coccia, E.; De Pasquale, S.; Di Giovanni, A.; D'Incecco, M.; Dreucci, M.; Fabbri, F. L.; Frolov, V.; Garbini, M.; Gemme, G.; Gnesi, I.; Gustavino, C.; Hatzifotiadou, D.; La Rocca, P.; Li, S.; Librizzi, F.; Maggiora, A.; Massai, M.; Miozzi, S.; Panareo, M.; Paoletti, R.; Perasso, L.; Pilo, F.; Piragino, G.; Regano, A.; Riggi, F.; Righini, G. C.; Sartorelli, G.; Scapparone, E.; Scribano, A.; Selvi, M.; Serci, S.; Siddi, E.; Spandre, G.; Squarcia, S.; Taiuti, M.; Tosello, F.; Votano, L.; Williams, M. C. S.; Yanez, G.; Zichichi, A.; Zouyevski, R.

    2014-10-01

    The Extreme Energy Events (EEE) Project is a Centro Fermi - CERN - INFN - MIUR Collaboration Project for the study of extremely high energy cosmic rays, which exploits the Multigap Resistive Plate Chamber (MRPC) technology. The excellent time resolution and good tracking capability of this kind of detector allows us to study Extensive Air Showers (EAS) with an array of MRPC telescopes distributed across the Italian territory. Each telescope is installed in a high school, with the further goal to introduce students to particle and astroparticle Physics. The status of the experiment and the results obtained are reported.

  12. A systemic approach for managing extreme risk events-dynamic financial analysis

    Directory of Open Access Journals (Sweden)

    Ph.D.Student Rodica Ianole

    2011-12-01

    Full Text Available Following the Black Swan logic, it often happens that what we do not know becomes more relevant that what we (believe to know. The management of extreme risks falls under this paradigm in the sense that it cannot be limited to a static approach based only on objective and easily quantifiable variables. Making appeal to the operational tools developed primarily for the insurance industry, the present paper aims to investigate how dynamic financial analysis (DFA can be used within the framework of extreme risk events.

  13. Simulation of the 23 July 2012 Extreme Space Weather Event: What if This Extremely Rare CME Was Earth Directed?

    Science.gov (United States)

    Ngwira, Chigomezyo M.; Pulkkinen, Antti; Mays, M. Leila; Kuznetsova, Maria M.; Galvin, A. B.; Simunac, Kristin; Baker, Daniel N.; Li, Xinlin; Zheng, Yihua; Glocer, Alex

    2013-01-01

    Extreme space weather events are known to cause adverse impacts on critical modern day technological infrastructure such as high-voltage electric power transmission grids. On 23 July 2012, NASA's Solar Terrestrial Relations Observatory-Ahead (STEREO-A) spacecraft observed in situ an extremely fast coronal mass ejection (CME) that traveled 0.96 astronomical units (approx. 1 AU) in about 19 h. Here we use the SpaceWeather Modeling Framework (SWMF) to perform a simulation of this rare CME.We consider STEREO-A in situ observations to represent the upstream L1 solar wind boundary conditions. The goal of this study is to examine what would have happened if this Rare-type CME was Earth-bound. Global SWMF-generated ground geomagnetic field perturbations are used to compute the simulated induced geoelectric field at specific ground-based active INTERMAGNET magnetometer sites. Simulation results show that while modeled global SYM-H index, a high-resolution equivalent of the Dst index, was comparable to previously observed severe geomagnetic storms such as the Halloween 2003 storm, the 23 July CME would have produced some of the largest geomagnetically induced electric fields, making it very geoeffective. These results have important practical applications for risk management of electrical power grids.

  14. Occurrence of extreme solar particle events: Assessment from historical proxy data

    CERN Document Server

    Usoskin, I G

    2012-01-01

    The probability of occurrence of extreme solar particle events (SPEs) with the fluence of (>30 MeV) protons F30>10^{10} cm^{-2} is evaluated based on data of cosmogenic isotopes 14C and 10Be in terrestrial archives centennial-millennial time scales. Four potential candidates with F30=(1-1.5)x10^{10} cm^{-2} and no events with F30>2x10^{10} cm^{-2} are identified since 1400 AD in the annually resolved 10Be data. A strong SPE related to the Carrington flare of 1859 AD is not supported by the data. For the last 11400 years, 19 SPE candidates with F30=(1-3)x10^{10} cm^{-2} are found and clearly no event with F30>5x10^{10} cm^{-2} (50-fold the SPE of 23-Feb-1956) occurring. This values serve as an observational upper limit for the strength of SPE on the time scale of tens of millennia. Two events, ca. 780 and 1460 AD, appear in different data series making them strong candidates to extreme SPEs. We built a distribution of the occurrence probability of extreme SPEs, providing a new strict observational constraint. ...

  15. Characterization of extreme flood and drought events in Singapore and investigation of their relationships with ENSO

    Science.gov (United States)

    Li, Xin; Babovic, Vladan

    2016-04-01

    Flood and drought are hydrologic extreme events that have significant impact on human and natural systems. Characterization of flood and drought in terms of their start, duration and strength, and investigation of the impact of natural climate variability (i.e., ENSO) and anthropogenic climate change on them can help decision makers to facilitate adaptions to mitigate potential enormous economic costs. To date, numerous studies in this area have been conducted, however, they are primarily focused on extra-tropical regions. Therefore, this study presented a detailed framework to characterize flood and drought events in a tropical urban city-state (i.e., Singapore), based on daily data from 26 precipitation stations. Flood and drought events are extracted from standardized precipitation anomalies from monthly to seasonal time scales. Frequency, duration and magnitude of flood and drought at all the stations are analyzed based on crossing theory. In addition, spatial variation of flood and drought characteristics in Singapore is investigated using ordinary kriging method. Lastly, the impact of ENSO condition on flood and drought characteristics is analyzed using regional regression method. The results show that Singapore can be prone to extreme flood and drought events at both monthly and seasonal time scales. ENSO has significant influence on flood and drought characteristics in Singapore, but mainly during the South West Monsoon season. During the El Niño phase, drought can become more extreme. The results have implications for water management practices in Singapore.

  16. 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.

  17. Environmental prediction, risk assessment and extreme events: adaptation strategies for the developing world.

    Science.gov (United States)

    Webster, Peter J; Jian, Jun

    2011-12-13

    The uncertainty associated with predicting extreme weather events has serious implications for the developing world, owing to the greater societal vulnerability to such events. Continual exposure to unanticipated extreme events is a contributing factor for the descent into perpetual and structural rural poverty. We provide two examples of how probabilistic environmental prediction of extreme weather events can support dynamic adaptation. In the current climate era, we describe how short-term flood forecasts have been developed and implemented in Bangladesh. Forecasts of impending floods with horizons of 10 days are used to change agricultural practices and planning, store food and household items and evacuate those in peril. For the first time in Bangladesh, floods were anticipated in 2007 and 2008, with broad actions taking place in advance of the floods, grossing agricultural and household savings measured in units of annual income. We argue that probabilistic environmental forecasts disseminated to an informed user community can reduce poverty caused by exposure to unanticipated extreme events. Second, it is also realized that not all decisions in the future can be made at the village level and that grand plans for water resource management require extensive planning and funding. Based on imperfect models and scenarios of economic and population growth, we further suggest that flood frequency and intensity will increase in the Ganges, Brahmaputra and Yangtze catchments as greenhouse-gas concentrations increase. However, irrespective of the climate-change scenario chosen, the availability of fresh water in the latter half of the twenty-first century seems to be dominated by population increases that far outweigh climate-change effects. Paradoxically, fresh water availability may become more critical if there is no climate change.

  18. Hydro-meteorological extreme events in the 18th century in Portugal

    Science.gov (United States)

    Fragoso, Marcelo; João Alcoforado, Maria; Taborda, João Paulo

    2013-04-01

    The present work is carried out in the frame of the KLIMHIST PROJECT ("Reconstruction and model simulations of past climate in Portugal using documentary and early instrumental sources, 17th-19th century)", and is devoted to the study of hydro-meteorological extreme events during the last 350 years, in order to understand how they have changed in time and compare them with current analogues. More specifically, the results selected to this presentation will focus on some hydro-meteorological extreme events of the 18th century, like severe droughts, heavy precipitation episodes and windstorms. One of the most noteworthy events was the winterstorm Bárbara (3rd to 6th December 1739), already studied in prior investigations (Taborda et al, 2004; Pfister et al, 2010), a devastating storm with strong impacts in Portugal caused by violent winds and heavy rainfall. Several other extreme events were detected by searching different documentary archives, including individual, administrative and ecclesiastic sources. Moreover, a more detailed insight to the 1783-1787 period will be made with regard the Lisbon region, taking into consideration the availability of information for daily meteorological observations as well as documentary evidences, like descriptions from Gazeta de Lisboa, the periodic with more continuous publication in the 18thcentury. Key-words: Instrumental data, Documentary data, Extreme events, Klimhist Project, Portugal References Pfister, C., Garnier, E., Alcoforado, M.J., Wheeler, D. Luterbacher, J. Nunes, M.F., Taborda, J.P. (2010) The meteorological framework and the cultural memory of three severe winter-storms in early eighteenth-century Europe, Climatic Change, 101, 1-2, 281-310 Taborda, JP; Alcoforado, MJ and Garcia, JC (2004) O Clima do Sul de Portugal no Séc.XVIII, Centro de Estudos Geográficos, Área de de Investigação de Geo-Ecologia, relatório no 2

  19. 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

  20. An open source web application for the surveillance and prevention of the impacts on public health of extreme meteorological events: the SUPREME system

    Science.gov (United States)

    2011-01-01

    Background Every year, many deaths or health problems are directly linked to heat waves. Consequently, numerous jurisdictions around the world have developed intervention plans that are employed during extreme heat events; beyond their emergency sections, these plans generally include preventive measures to be implemented each year. Over the last five years, local and regional information systems have been implemented in a few Canadian cities for surveillance purposes. However, until recently, no such systems existed at the provincial level. In the context of the Government of Quebec's 2006-2012 Action Plan on Climate Change, a real-time integrated system for the surveillance and monitoring of extreme heat events has been implemented on a provincial level. The system is a component of a broader approach that would also monitor the public health impacts of all types of extreme meteorological events. Results After conducting a detailed needs analysis, the Quebec National Institute for Public Health developed and implemented an integrated web application leveraging open source software for the real-time Surveillance and Prevention of the impacts of Extreme Meteorological Events on public health, called the SUPREME system. Its first field use involved heat waves. This decision-support system is based on open source software and is composed of four modules: (1) data acquisition and integration, (2) risk analysis and alerts, (3), cartographic application, and (4) information dissemination - climate change and health portal. The system is available to health specialists through a secure web information portal and provides access to weather forecasts, historic and real-time indicators (including deaths and hospital admissions), alerts and various cartographic data used for conducting prevention activities and launching emergency measures. Conclusions The SUPREME system was implemented and used during the summer of 2010. It served as an important decision-making tool during

  1. An open source web application for the surveillance and prevention of the impacts on public health of extreme meteorological events: the SUPREME system.

    Science.gov (United States)

    Toutant, Steve; Gosselin, Pierre; Bélanger, Diane; Bustinza, Ray; Rivest, Sonia

    2011-05-25

    Every year, many deaths or health problems are directly linked to heat waves. Consequently, numerous jurisdictions around the world have developed intervention plans that are employed during extreme heat events; beyond their emergency sections, these plans generally include preventive measures to be implemented each year. Over the last five years, local and regional information systems have been implemented in a few Canadian cities for surveillance purposes. However, until recently, no such systems existed at the provincial level. In the context of the Government of Quebec's 2006-2012 Action Plan on Climate Change, a real-time integrated system for the surveillance and monitoring of extreme heat events has been implemented on a provincial level. The system is a component of a broader approach that would also monitor the public health impacts of all types of extreme meteorological events. After conducting a detailed needs analysis, the Quebec National Institute for Public Health developed and implemented an integrated web application leveraging open source software for the real-time Surveillance and Prevention of the impacts of Extreme Meteorological Events on public health, called the SUPREME system. Its first field use involved heat waves. This decision-support system is based on open source software and is composed of four modules: (1) data acquisition and integration, (2) risk analysis and alerts, (3), cartographic application, and (4) information dissemination - climate change and health portal. The system is available to health specialists through a secure web information portal and provides access to weather forecasts, historic and real-time indicators (including deaths and hospital admissions), alerts and various cartographic data used for conducting prevention activities and launching emergency measures. The SUPREME system was implemented and used during the summer of 2010. It served as an important decision-making tool during the July 2010 heat wave in the

  2. 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.

  3. 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.

  4. On the Co-occurrence of Air Quality Extremes and Heat Waves

    Science.gov (United States)

    Schnell, J.; Prather, M. J.

    2015-12-01

    We investigate the relationship between observed maximum extremes of ozone, PM2.5, temperature over eastern North America during 15 extended summer seasons (April-September, 1999-2013). We use an objective mapping algorithm to calculate a 1° x 1° grid-cell averaged product of (1) the maximum daily 8-hour average of surface ozone abundance and (2) the daily average PM2.5 abundance from surface monitoring networks in the US and Canada. In addition, we use ECMWF reanalysis data to generate a 1° x 1° grid-cell averaged product of (3) the maximum temperature at 2-meter height. The extreme maxima for these 3 data sets are defined at each grid cell as the 50 days with the highest value in three 5-year windows (~94.5 percentile of all Apr-Sep days). These extremes for ozone, particles and temperature are denoted OX, PX, and TX, respectively. Extreme ozone and PM2.5 most often occur together (35% of OX and PX events in a cell occur simultaneously), followed by PM2.5 and temperature (29%), ozone and temperature (27%), and all three (15%). In all cases, the greatest co-occurrence is found in the northeast US (>50% for two co-occurring events). We find that the day after any extreme is also likely to be an extreme of any kind (p > 75%) and that the most likely follow-on extreme is of the same type (p = 20-40%). The northeast US is an exception where OX are more likely to be followed by PX. Extreme episodes (defined as multi-day, spatially connected events) typically originate as an OX event, followed by PX and then TX. This ordering is also evident in the generalized spatial structure of episodes: OX occur at the center and the eastern leading edge, PX are found to the immediate northwest, and TX surround the OX and PX events. The largest OX and PX episodes are similar in size, but TX episodes are usually larger and longer lasting. In general, extremes are more likely to co-occur for larger episodes. The intensity of OX, PX, and TX events is measured as the % above the 5

  5. Comparison of annual maximum series and partial duration series methods for modeling extreme hydrologic events

    DEFF Research Database (Denmark)

    Madsen, Henrik; Rasmussen, Peter F.; Rosbjerg, Dan

    1997-01-01

    Two different models for analyzing extreme hydrologic events, based on, respectively, partial duration series (PDS) and annual maximum series (AMS), are compared. The PDS model assumes a generalized Pareto distribution for modeling threshold exceedances corresponding to a generalized extreme value...... model with ML estimation for large positive shape parameters. Since heavy-tailed distributions, corresponding to negative shape parameters, are far the most common in hydrology, the PDS model generally is to be preferred for at-site quantile estimation....... distribution for annual maxima. The performance of the two models in terms of the uncertainty of the T-year event estimator is evaluated in the cases of estimation with, respectively, the maximum likelihood (ML) method, the method of moments (MOM), and the method of probability weighted moments (PWM...

  6. 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

  7. Resilience of coastal wetlands to extreme hydrologic events in Apalachicola Bay

    Science.gov (United States)

    Tahsin, Subrina; Medeiros, Stephen C.; Singh, Arvind

    2016-07-01

    Extreme hydrologic events such as hurricanes and droughts continuously threaten wetlands which provide key ecosystem services in coastal areas. The recovery time for vegetation after impact from these extreme events can be highly variable depending on the hazard type and intensity. Apalachicola Bay in Florida is home to a rich variety of saltwater and freshwater wetlands and is subject to a wide range of hydrologic hazards. Using spatiotemporal changes in Landsat-based empirical vegetation indices, we investigate the impact of hurricane and drought on both freshwater and saltwater wetlands from year 2000 to 2015 in Apalachicola Bay. Our results indicate that saltwater wetlands are more resilient than freshwater wetlands and suggest that in response to hurricanes, the coastal wetlands took almost a year to recover, while recovery following a drought period was observed after only a month.

  8. Extreme event return times in long-term memory processes near 1/f

    Science.gov (United States)

    Blender, R.; Fraedrich, K.; Sienz, F.

    2008-07-01

    The distribution of extreme event return times and their correlations are analyzed in observed and simulated long-term memory (LTM) time series with 1/f power spectra. The analysis is based on tropical temperature and mixing ratio (specific humidity) time series from TOGA COARE with 1 min resolution and an approximate 1/f power spectrum. Extreme events are determined by Peak-Over-Threshold (POT) crossing. The Weibull distribution represents a reasonable fit to the return time distributions while the power-law predicted by the stretched exponential for 1/f deviates considerably. For a comparison and an analysis of the return time predictability, a very long simulated time series with an approximate 1/f spectrum is produced by a fractionally differenced (FD) process. This simulated data confirms the Weibull distribution (a power law can be excluded). The return time sequences show distinctly weaker long-term correlations than the original time series (correlation exponent γ≍0.56).

  9. Variability of continental water storage and its relationship to extreme hydrological events in the Amazon basin

    Directory of Open Access Journals (Sweden)

    Ana Emília Diniz Silva Guedes

    2013-08-01

    Full Text Available In this paper, we evaluated the variability of total continental water storage derived from estimates of balance water using satellite data in association with hydro-meteorological data. The occurrence of extreme hydrological events such as drought and flood in the Amazon basin was related to the variability of total storage of continental water. Both estimation methods (PER- Precipitation, Evapotranspiration and Runoff and GRACE show a strong decrease in water storage during the 2005 drought and a strong recovery during the 2009 flood. The results show that there is strong relationship between the occurrences of extreme hydrological events and water storage in the Amazon. Local and deep measurements of continental water storage can provide more precise indications of the dynamics of the hydrological system and its response to climate variability.

  10. Credible occurrence probabilities for extreme geophysical events: earthquakes, volcanic eruptions, magnetic storms

    Science.gov (United States)

    Love, Jeffrey J.

    2012-01-01

    Statistical analysis is made of rare, extreme geophysical events recorded in historical data -- counting the number of events $k$ with sizes that exceed chosen thresholds during specific durations of time $\\tau$. Under transformations that stabilize data and model-parameter variances, the most likely Poisson-event occurrence rate, $k/\\tau$, applies for frequentist inference and, also, for Bayesian inference with a Jeffreys prior that ensures posterior invariance under changes of variables. Frequentist confidence intervals and Bayesian (Jeffreys) credibility intervals are approximately the same and easy to calculate: $(1/\\tau)[(\\sqrt{k} - z/2)^{2},(\\sqrt{k} + z/2)^{2}]$, where $z$ is a parameter that specifies the width, $z=1$ ($z=2$) corresponding to $1\\sigma$, $68.3\\%$ ($2\\sigma$, $95.4\\%$). If only a few events have been observed, as is usually the case for extreme events, then these "error-bar" intervals might be considered to be relatively wide. From historical records, we estimate most likely long-term occurrence rates, 10-yr occurrence probabilities, and intervals of frequentist confidence and Bayesian credibility for large earthquakes, explosive volcanic eruptions, and magnetic storms.

  11. Power Outages, Extreme Events and Health: a Systematic Review of the Literature from 2011-2012

    OpenAIRE

    Klinger, Chaamala; Landeg, Owen; Murray, Virginia

    2014-01-01

    Background Extreme events (e.g. flooding) threaten critical infrastructure including power supplies. Many interlinked systems in the modern world depend on a reliable power supply to function effectively. The health sector is no exception, but the impact of power outages on health is poorly understood. Greater understanding is essential so that adverse health impacts can be prevented and/or mitigated. Methods We searched Medline, CINAHL and Scopus for papers about the health impacts of power ...

  12. Indications of an extreme event deposits along the west coast of India: evidences from GPR investigations

    Digital Repository Service at National Institute of Oceanography (India)

    Loveson, V.J.; Gujar, A.R.; Iyer, S.D.; Srivastava, P.; Tirodkar, G.; Luis, R.A.A.

    architecture of sedimentary bed sets, to trace paleo-channels and to reconstruct fluvial dynamics are well known (Vandenberghe and van Overmeeren 1999; Neal et al. 2002; Gourry et al. 2003; Sridhar and Patidar 2005; Smith et al. 2006; Smith et al. 2009... architecture of extreme event deposits were established by various earlier studies (Neal 2002; Loveson et al. 2005; Loveson and Gujar 2010; Shukla 2012; Koster, 2012; Loveson et al. 2014). The main goals of the present study were to investigate...

  13. Modelling of extreme rainfall events in Peninsular Malaysia based on annual maximum and partial duration series

    Science.gov (United States)

    Zin, Wan Zawiah Wan; Shinyie, Wendy Ling; Jemain, Abdul Aziz

    2015-02-01

    In this study, two series of data for extreme rainfall events are generated based on Annual Maximum and Partial Duration Methods, derived from 102 rain-gauge stations in Peninsular from 1982-2012. To determine the optimal threshold for each station, several requirements must be satisfied and Adapted Hill estimator is employed for this purpose. A semi-parametric bootstrap is then used to estimate the mean square error (MSE) of the estimator at each threshold and the optimal threshold is selected based on the smallest MSE. The mean annual frequency is also checked to ensure that it lies in the range of one to five and the resulting data is also de-clustered to ensure independence. The two data series are then fitted to Generalized Extreme Value and Generalized Pareto distributions for annual maximum and partial duration series, respectively. The parameter estimation methods used are the Maximum Likelihood and the L-moment methods. Two goodness of fit tests are then used to evaluate the best-fitted distribution. The results showed that the Partial Duration series with Generalized Pareto distribution and Maximum Likelihood parameter estimation provides the best representation for extreme rainfall events in Peninsular Malaysia for majority of the stations studied. Based on these findings, several return values are also derived and spatial mapping are constructed to identify the distribution characteristic of extreme rainfall in Peninsular Malaysia.

  14. Agent Based Simulation of Group Emotions Evolution and Strategy Intervention in Extreme Events

    Directory of Open Access Journals (Sweden)

    Bo Li

    2014-01-01

    Full Text Available Agent based simulation method has become a prominent approach in computational modeling and analysis of public emergency management in social science research. The group emotions evolution, information diffusion, and collective behavior selection make extreme incidents studies a complex system problem, which requires new methods for incidents management and strategy evaluation. This paper studies the group emotion evolution and intervention strategy effectiveness using agent based simulation method. By employing a computational experimentation methodology, we construct the group emotion evolution as a complex system and test the effects of three strategies. In addition, the events-chain model is proposed to model the accumulation influence of the temporal successive events. Each strategy is examined through three simulation experiments, including two make-up scenarios and a real case study. We show how various strategies could impact the group emotion evolution in terms of the complex emergence and emotion accumulation influence in extreme events. This paper also provides an effective method of how to use agent-based simulation for the study of complex collective behavior evolution problem in extreme incidents, emergency, and security study domains.

  15. Variations of Dissolved Iron in the Amur River During an Extreme Flood Event in 2013

    Institute of Scientific and Technical Information of China (English)

    YAN Baixing; GUAN Jiunian; Vladimir SHESTERKIN; ZHU Hui

    2016-01-01

    As a key factor limiting primary productivity in marine ecosystem,dissolved iron (DFe) export from fluvial systems has increased recently.There is particular concern about discharges of DFe during extreme flooding,when they are thought to increase considerably.An extreme flood event that caused inundation of extensive areas of Far Eastern Russia and Northeastern China occurred in the basin of the Amur River during summer and autumn 2013.During this event,water samples were collected in the middle reaches of the Amur River and the lower reaches at Khabarovsk City and analyzed for DFe concentrations and other aquatic parameters.The resuits show that the average DFe concentrations in the middle reaches of the Amur River (right bank) and at Khabarovsk were 1.11 mg/L and 0.32 mg/L,respectively,during the extreme flood in 2013.The total discharge of DFe during the flood event was 6.25 x 104 t.The high discharge of DFe during the flood reflects the elevated discharge of the river,hydrologically connected riparian wetlands,vast quantities of terrestrial runoff,and flood discharges from the Zeya and Bureya reservoirs.These results show that long-term monitoring is needed to identify and assess the impacts of DFe transport on the downstream reaches,estuarine area,and coastal ecosystems of the Amur River.

  16. Herding interactions as an opportunity to prevent extreme events in financial markets

    Science.gov (United States)

    Kononovicius, Aleksejus; Gontis, Vygintas

    2015-07-01

    A characteristic feature of complex systems in general is a tight coupling between their constituent parts. In complex socio-economic systems this kind of behavior leads to self-organization, which may be both desirable (e.g. social cooperation) and undesirable (e.g. mass panic, financial "bubbles" or "crashes"). Abundance of the empirical data as well as general insights into the trading behavior enables the creation of simple agent-based models reproducing sophisticated statistical features of the financial markets. In this contribution we consider a possibility to prevent self-organized extreme events in financial market modeling its behavior using agent-based herding model, which reproduces main stylized facts of the financial markets. We show that introduction of agents with predefined fundamentalist trading behavior helps to significantly reduce the probability of the extreme price fluctuations events. We also investigate random trading, which was previously found to be promising extreme event prevention strategy, and find that its impact on the market has to be considered among other opportunities to stabilize the markets.

  17. Modelling the extreme precipitation event over Madeira Island on 20 February 2010

    Directory of Open Access Journals (Sweden)

    T. Luna

    2011-09-01

    Full Text Available In the morning of the 20 February of 2010 an extreme precipitation event occurred over Madeira Island. This event triggered several flash floods and mudslides in the southern parts of the island, resulting in 42 confirmed deaths, 100 injured, and at least 8 people still missing. These extreme weather conditions were associated to a weather frontal system moving northeastwards embedded in a low pressure area centered in the Azores archipelago. This storm was one in a series of such storms that affected Portugal, Spain, Morocco and the Canary islands causing flooding and strong winds. These storms were bolstered by an unusually strong sea surface temperature gradient across the Atlantic Ocean.

    In this study, the WRF model is used to evaluate the intensity and predictability of this precipitation extreme event over the island. The synoptic/orographic nature of the precipitation is also evaluated, as well as the sensitivity of the model to horizontal resolution and cumulus parameterization. Orography was found to be the main factor explaining the occurrence, amplitude and phase of precipitation over the Island.

  18. Relationships between interdecadal variability and extreme precipitation events in South America during the monsoon season

    Science.gov (United States)

    Grimm, Alice; Laureanti, Nicole; Rodakoviski, Rodrigo

    2016-04-01

    This study aims to clarify the impact of interdecadal climate oscillations (periods of 8 years and longer) on the frequency of extreme precipitation events over South America in the monsoon season (austral spring and summer), and determine the influence of these oscillations on the daily precipitation frequency distribution. Interdecadal variability modes of precipitation during the monsoon season are provided by a continental-scale rotated empirical orthogonal function analysis for the 60 years period 1950-2009. The main disclosed modes are robust, since they are reproduced for different periods. They can produce differences around 50% in monthly precipitation between opposite phases. Oceanic and atmospheric anomalous fields associated with these modes indicate that they have physical basis. The first modes in spring and summer display highest correlation with the Interdecadal Pacific Oscillation (IPO) SST mode, while the second modes have strongest correlation with the Atlantic Multidecadal Oscillation (AMO) SST mode. However, there are also other influences on these modes. As the most dramatic consequences of climate variability stem from its influence on the frequency of extreme precipitation events, it is important to also assess this influence, since variations in monthly or seasonal precipitation do not necessarily imply significant alterations in their extreme events. This study seeks to answer the questions: i) Do opposite phases of the main interdecadal modes of seasonal precipitation produce significant anomalies in the frequency of extreme events? ii) Does the interdecadal variability of the frequency of extreme events show similar spatial and temporal structure as the interdecadal variability of the seasonal precipitation? iii) Does the interdecadal variability change the daily precipitation probability distribution between opposite phases? iv) In this case, which ranges of daily precipitation are most affected? The significant anomalies of the extreme

  19. Testing for scale-invariance in extreme events, with application to earthquake occurrence

    Science.gov (United States)

    Main, I.; Naylor, M.; Greenhough, J.; Touati, S.; Bell, A.; McCloskey, J.

    2009-04-01

    We address the generic problem of testing for scale-invariance in extreme events, i.e. are the biggest events in a population simply a scaled model of those of smaller size, or are they in some way different? Are large earthquakes for example ‘characteristic', do they ‘know' how big they will be before the event nucleates, or is the size of the event determined only in the avalanche-like process of rupture? In either case what are the implications for estimates of time-dependent seismic hazard? One way of testing for departures from scale invariance is to examine the frequency-size statistics, commonly used as a bench mark in a number of applications in Earth and Environmental sciences. Using frequency data however introduces a number of problems in data analysis. The inevitably small number of data points for extreme events and more generally the non-Gaussian statistical properties strongly affect the validity of prior assumptions about the nature of uncertainties in the data. The simple use of traditional least squares (still common in the literature) introduces an inherent bias to the best fit result. We show first that the sampled frequency in finite real and synthetic data sets (the latter based on the Epidemic-Type Aftershock Sequence model) converge to a central limit only very slowly due to temporal correlations in the data. A specific correction for temporal correlations enables an estimate of convergence properties to be mapped non-linearly on to a Gaussian one. Uncertainties closely follow a Poisson distribution of errors across the whole range of seismic moment for typical catalogue sizes. In this sense the confidence limits are scale-invariant. A systematic sample bias effect due to counting whole numbers in a finite catalogue makes a ‘characteristic'-looking type extreme event distribution a likely outcome of an underlying scale-invariant probability distribution. This highlights the tendency of ‘eyeball' fits unconsciously (but wrongly in

  20. Extreme climate events over northern China during the last 50 years

    Institute of Scientific and Technical Information of China (English)

    HANHui; GONGDaoyi

    2003-01-01

    Climate extremes for agriculture-pasture transitional zone, northem China, are analyzed on the basis of daily mean temperature and precipitation observations for 31 stations in the period 1956-2001. Analysis season for precipitation is May-September, i.e., the rainy season. For temperature is the hottest three months, i.e., June through August. Heavy rain events, defined as those with daily precipitation equal to or larger than 50 mm, show no significant secular trend. A jump-like change, however, is found occurring in about 1980. For the period 1980-1993, the frequency of heavy rain events is significantly lower than the previous periods. Simultaneously, the occurring time of heavy rains expanded, commencing about one month early and ending one month later. Long dry spells are defined as those with longer than 10 days without rainfall. The frequency of long dry spells displays a significant (at the 99% confidence level) trend at the value of +8.3% /10a. That may be one of the major causes of the frequent droughts emerging over northern China during the last decades. Extremely hot and low temperature events are defined as the uppermost 10% daily temperatures and the lowest 10% daily temperatures, respectively. There is a weak and non-significant upward trend in frequency of extremely high temperatures from the 1950s to the mid-1990s. But the number of hot events increases as much as twice since 1997. That coincides well with the sudden rise in mean summer temperature for the same period. Contrary to that, the fiequency of low temperature events have been decreasing steadily since the 1950s, with a significant linear trend of-15%/10a.

  1. Processes and Geomorphological Impacts of an Extreme Flash Flood Event in SE Spain

    Science.gov (United States)

    Hooke, J.

    2015-12-01

    A major flash flood event took place on 28 September, 2012 in SE Spain, resulting in 10 fatalities and much damage to infrastructure regionally. The flood affected long-term monitoring sites in two catchments in which morphological changes and flow dynamics of these ephemeral channels were being measured. Thus detailed data on channel state prior to the flood were available. The flood event in the Nogalte catchment was extreme in its peak flow, rate of rise and unit runoff. The catchment has steep relief and much bare soil under almond groves, resulting in high sediment supply. The channel is confined in places, but mostly wide and braided, composed of loose gravel and occupying much of the valley floor. Flow was spatially continuous, with high connectivity throughout the catchment. The flood effects were net depositional in the monitored sites, with massive sedimentation on the channel bars. Vegetation was destroyed. Bank erosion and destruction of embankments took place in some locations. Hydraulic calculations indicate very high velocities, stream power and Froude numbers. Modelling and field evidence demonstrate extremely high sediment competence and sediment loadings. The influence of the event dynamics on processes and net outcomes is discussed. The impacts are compared with other events in this and neighbouring catchments. Overall, the event in the Nogalte did not alter the morphology markedly in spite of its extreme characteristics. It is suggested that these valley floors are adapted to this type of flash flood but that flows of such force and magnitude need to be allowed for in management in such an environment.

  2. Short time step continuous rainfall modeling and simulation of extreme events

    Science.gov (United States)

    Callau Poduje, A. C.; Haberlandt, U.

    2017-09-01

    The design, planning, operation and overall assessment of urban drainage systems require long and continuous rain series in a high temporal resolution. Unfortunately, the availability of this data is usually short. Nevertheless a precipitation model could be used to tackle this shortcoming; therefore it is in the aim of this study to present a stochastic point precipitation model to reproduce average rainfall event properties along with extreme values. For this purpose a model is proposed to generate long synthetic series of rainfall for a temporal resolution of 5 min. It is based on an alternating renewal framework and events are characterized by variables describing durations, amounts and peaks. A group of 24 stations located in the north of Germany is used to set up and test the model. The adequate modeling of joint behaviour of rainfall amount and duration is found to be essential for reproducing the observed properties, especially for the extreme events. Copulas are advantageous tools for modeling these variables jointly; however caution must be taken in the selection of the proper copula. The inclusion of seasonality and small events is as well tested and found to be useful. The model is directly validated by generating long synthetic time series and comparing them with observed ones. An indirect validation is as well performed based on a fictional urban hydrological system. The proposed model is capable of reproducing seasonal behaviour and main characteristics of the rainfall events including extremes along with urban flooding and overflow behaviour. Overall the performance of the model is acceptable compared to the design practice. The proposed model is simple to interpret, fast to implement and to transfer to other regions, whilst showing acceptable results.

  3. Nitrogen accumulation and partitioning in a High Arctic tundra ecosystem from extreme atmospheric N deposition events

    Energy Technology Data Exchange (ETDEWEB)

    Choudhary, Sonal, E-mail: S.Choudhary@sheffield.ac.uk [Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom); Management School, University of Sheffield, Conduit Road, Sheffield S10 1FL (United Kingdom); Blaud, Aimeric [Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom); Osborn, A. Mark [Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom); School of Applied Sciences, RMIT University, PO Box 71, Bundoora, VIC 3083 (Australia); Press, Malcolm C. [School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Manchester Metropolitan University, Manchester, M15 6BH (United Kingdom); Phoenix, Gareth K. [Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom)

    2016-06-01

    Arctic ecosystems are threatened by pollution from recently detected extreme atmospheric nitrogen (N) deposition events in which up to 90% of the annual N deposition can occur in just a few days. We undertook the first assessment of the fate of N from extreme deposition in High Arctic tundra and are presenting the results from the whole ecosystem {sup 15}N labelling experiment. In 2010, we simulated N depositions at rates of 0, 0.04, 0.4 and 1.2 g N m{sup −2} yr{sup −1}, applied as {sup 15}NH{sub 4}{sup 15}NO{sub 3} in Svalbard (79{sup °}N), during the summer. Separate applications of {sup 15}NO{sub 3}{sup −} and {sup 15}NH{sub 4}{sup +} were also made to determine the importance of N form in their retention. More than 95% of the total {sup 15}N applied was recovered after one growing season (~ 90% after two), demonstrating a considerable capacity of Arctic tundra to retain N from these deposition events. Important sinks for the deposited N, regardless of its application rate or form, were non-vascular plants > vascular plants > organic soil > litter > mineral soil, suggesting that non-vascular plants could be the primary component of this ecosystem to undergo measurable changes due to N enrichment from extreme deposition events. Substantial retention of N by soil microbial biomass (70% and 39% of {sup 15}N in organic and mineral horizon, respectively) during the initial partitioning demonstrated their capacity to act as effective buffers for N leaching. Between the two N forms, vascular plants (Salix polaris) in particular showed difference in their N recovery, incorporating four times greater {sup 15}NO{sub 3}{sup −} than {sup 15}NH{sub 4}{sup +}, suggesting deposition rich in nitrate will impact them more. Overall, these findings show that despite the deposition rates being extreme in statistical terms, biologically they do not exceed the capacity of tundra to sequester pollutant N during the growing season. Therefore, current and future extreme events

  4. 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

  5. Spatiotemporal distribution characteristics and attribution of extreme regional low temperature event

    Institute of Scientific and Technical Information of China (English)

    封泰晨; 张珂铨; 苏海晶; 王晓娟; 龚志强; 张文煜

    2015-01-01

    Based on an objective identification technique for regional low temperature event (OITRLTE), the daily minimum temperature in China has been detected from 1960 to 2013. During this period, there were 60 regional extreme low temperature events (ERLTEs), which are included in the 690 regional low temperature events (RLTEs). The 60 ERLTEs are analyzed in this paper. The results show that in the last 50 years, the intensity of the ERLTEs has become weak;the number of lasted days has decreased;and, the affected area has become small. However, that situation has changed in this century. In terms of spatial distribution, the high intensity regions are mainly in Northern China while the high frequency regions concentrate in Central and Eastern China. According to the affected area of each event, the 60 ERLTEs are classified into six types. The atmospheric circulation background fields which correspond to these types are also analyzed. The results show that, influenced by stronger blocking highs of Ural and Lake Baikal, as well as stronger southward polar vortex and East Asia major trough at 500-hPa geopotential height, cold air from high latitudes is guided to move southward and abnormal northerly winds at 850 hPa makes the cold air blow into China along diverse paths, thereby forming different types of regional extreme low temperatures in winter.

  6. Investigation of Meteorological Extreme Events in the North-East of Iran

    Directory of Open Access Journals (Sweden)

    S. Kouzegaran

    2016-02-01

    Full Text Available Introduction: Over the past hundred years, human activity has significantly altered the atmosphere and increase of concentration of greenhouse gases lead to warm the earth's surface. This global warming leads to change of climatic extreme index and increases the intensity and frequency of occurrence of extreme climate events. Investigation of extreme values for planning and policy for the agricultural sector and water resource management is important.In this study, a comprehensive review of extreme indices of temperature and precipitation are discussed. This paper aims to investigate extreme temperature and precipitation indices defined in accordance with CCL, and the study of other climatic parameters in the North East of Iran. Materials and Methods: In this research, statistics and data of some stations in the North East of Iran during the period 1992-2012 were used. To evaluate the extreme climate indices trend, 27 indices of rainfall and temperature, were defined by the ETCCDMI. They were calculated by RClimdex software. In this software, prior to the index calculation, data by quality control software became quantitative and incorrect data were controlled and outlier data were examined. The indices were calculated by daily data. 11 rainfall and 16 temperature indices were calculated by this software.The target of the ETCCDMI process is to delineate a standardized set of indices allowing for comparison across regions. These extreme indices were classified in five categories which included the percentile-based extreme indices, the absolute extreme indices, the threshold extreme indices, the periodic extreme indices, and the other indices. They were estimated at the 0.05 significant levels. The Mann-Kendall test was used to investigate the climatic parameters, maximum relative humidity, sunshine duration and maximum wind speed. Results and Discussion: Thermal analysis results are consistent with warming patterns, and they have showed that hot

  7. Non-parametric frequency analysis of extreme values for integrated disaster management considering probable maximum events

    Science.gov (United States)

    Takara, K. T.

    2015-12-01

    This paper describes a non-parametric frequency analysis method for hydrological extreme-value samples with a size larger than 100, verifying the estimation accuracy with a computer intensive statistics (CIS) resampling such as the bootstrap. Probable maximum values are also incorporated into the analysis for extreme events larger than a design level of flood control. Traditional parametric frequency analysis methods of extreme values include the following steps: Step 1: Collecting and checking extreme-value data; Step 2: Enumerating probability distributions that would be fitted well to the data; Step 3: Parameter estimation; Step 4: Testing goodness of fit; Step 5: Checking the variability of quantile (T-year event) estimates by the jackknife resampling method; and Step_6: Selection of the best distribution (final model). The non-parametric method (NPM) proposed here can skip Steps 2, 3, 4 and 6. Comparing traditional parameter methods (PM) with the NPM, this paper shows that PM often underestimates 100-year quantiles for annual maximum rainfall samples with records of more than 100 years. Overestimation examples are also demonstrated. The bootstrap resampling can do bias correction for the NPM and can also give the estimation accuracy as the bootstrap standard error. This NPM has advantages to avoid various difficulties in above-mentioned steps in the traditional PM. Probable maximum events are also incorporated into the NPM as an upper bound of the hydrological variable. Probable maximum precipitation (PMP) and probable maximum flood (PMF) can be a new parameter value combined with the NPM. An idea how to incorporate these values into frequency analysis is proposed for better management of disasters that exceed the design level. The idea stimulates more integrated approach by geoscientists and statisticians as well as encourages practitioners to consider the worst cases of disasters in their disaster management planning and practices.

  8. 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.

  9. Observation of extremely strong shock waves in solids launched by petawatt laser heating

    Science.gov (United States)

    Lancaster, K. L.; Robinson, A. P. L.; Pasley, J.; Hakel, P.; Ma, T.; Highbarger, K.; Beg, F. N.; Chen, S. N.; Daskalova, R. L.; Freeman, R. R.; Green, J. S.; Habara, H.; Jaanimagi, P.; Key, M. H.; King, J.; Kodama, R.; Krushelnick, K.; Nakamura, H.; Nakatsutsumi, M.; MacKinnon, A. J.; MacPhee, A. G.; Stephens, R. B.; Van Woerkom, L.; Norreys, P. A.

    2017-08-01

    Understanding hydrodynamic phenomena driven by fast electron heating is important for a range of applications including fast electron collimation schemes for fast ignition and the production and study of hot, dense matter. In this work, detailed numerical simulations modelling the heating, hydrodynamic evolution, and extreme ultra-violet (XUV) emission in combination with experimental XUV images indicate shock waves of exceptional strength (200 Mbar) launched due to rapid heating of materials via a petawatt laser. We discuss in detail the production of synthetic XUV images and how they assist us in interpreting experimental XUV images captured at 256 eV using a multi-layer spherical mirror.

  10. Spatial patterns of sediment dynamics within a medium-sized watershed over an extreme storm event

    Science.gov (United States)

    Gao, Peng; Zhang, Zhirou

    2016-08-01

    In this study, we quantified spatial patterns of sediment dynamics in a watershed of 311 km2 over an extreme storm event using watershed modeling and statistical analyses. First, we calibrated a watershed model, Dynamic Watershed Simulation Model (DWSM) by comparing the predicted with calculated hydrograph and sedigraph at the outlet for this event. Then we predicted values of event runoff volume (V), peak flow (Qpeak), and two types of event sediment yields for lumped morphological units that contain 42 overland elements and 21 channel segments within the study watershed. Two overland elements and the connected channel segment form a first-order subwatershed, several of which constitute a larger nested subwatershed. Next we examined (i) the relationships between these variables and area (A), precipitation (P), mean slope (S), soil erodibility factor, and percent of crop and pasture lands for all overland elements (i.e., the small spatial scale, SSS), and (ii) those between sediment yield, Qpeak, A, P, and event runoff depth (h) for the first-order and nested subwatersheds along two main creeks of the study watershed (i.e., the larger spatial scales, LSS). We found that at the SSS, sediment yield was nonlinearly well related to A and P, but not Qpeak and h; whereas at the LSS, linear relationships between sediment yield and Qpeak existed, so did the Qpeak-A, and Qpeak-P relationships. This linearity suggests the increased connectivity from the SSS to LSS, which was caused by ignorance of channel processes within overland elements. It also implies that sediment was transported at capacity during the extreme event. So controlling sediment supply from the most erodible overland elements may not efficiently reduce the downstream sediment load.

  11. Observed changes in seasonal heat waves and warm temperature extremes in the Romanian Carpathians

    Science.gov (United States)

    Micu, Dana; Birsan, Marius-Victor; Dumitrescu, Alexandru; Cheval, Sorin

    2015-04-01

    Extreme high temperature have a large impact on environment and human activities, especially in high elevation areas particularly sensitive to the recent climate warming. The climate of the Romanian Carpathians became warmer particularly in winter, spring and summer, exibiting a significant increasing frequency of warm extremes. The paper investigates the seasonal changes in the frequency, duration and intensity of heat waves in relation to the shifts in the daily distribution of maximum temperatures over a 50-year period of meteorological observations (1961-2010). The paper uses the heat wave definition recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI) and exploits the gridded daily dataset of maximum temperature at 0.1° resolution (~10 km) developed in the framework of the CarpatClim project (www.carpatclim.eu). The seasonal changes in heat waves behavior were identified using the Mann-Kendall non-parametric trend test. The results suggest an increase in heat wave frequency and a lengthening of intervals affected by warm temperature extremes all over the study region, which are explained by the shifts in the upper (extreme) tail of the daily maximum temperature distribution in most seasons. The trends are consistent across the region and are well correlated to the positive phases of the East Atlantic Oscillation. Our results are in good agreement with the previous temperature-related studies concerning the Carpathian region. This study was realized within the framework of the project GENCLIM, financed by UEFISCDI, code PN-II 151/2014.

  12. Workers’ perceptions of climate change related extreme heat exposure in South Australia: a cross-sectional survey

    OpenAIRE

    Xiang, Jianjun; Hansen, Alana; Pisaniello, Dino; Bi, Peng

    2016-01-01

    Background Occupational exposure to extreme heat without sufficient protection may not only increase the risk of heat-related illnesses and injuries but also compromise economic productivity. With predictions of more frequent and intense bouts of hot weather, workplace heat exposure is presenting a growing challenge to workers’ health and safety. This study aims to investigate workers’ perceptions and behavioural responses towards extreme heat exposure in a warming climate. Methods A cross-se...

  13. Mitigation Efforts in Rural Communities after Extreme Weather Events - New Insights for Stakeholders

    Directory of Open Access Journals (Sweden)

    Vesela Radovic

    2016-09-01

    Full Text Available Global climate changes are undoubtedly course of the increasing frequency of extreme whether events all over the world. Rural communities belong to the “group of victims” which is greatly jeopardized by consequences of the extreme weather events. Having in mind limited capacities for the preparedness, response and recovery after any kind of emergency it is clear that the rural community mostly needs external help. That is the point of this paper: to make new insights about this important issue, and to discuss: “how to provide adequate help in the rural communities and build adequate adaptive and response capacities”. In many countries agriculture and rural tourism are main economic activities in the rural area and its interruption could be the obstacle for implementation of sustainable development. Various stakeholders omit to be aware of this issue. Emergency agencies and many others have to make the comprehensive plan for rural communities (having in mind all its limitations. In the Republic of Serbia rural communities do not have enough capacity for recovery and usually it takes many years after an event. A minimum of an economic recovery standard has to be created for the rural community. It also has to be a specific contingency plan in the future reorganizations of emergency services in Serbia and at the Western Balkan region. It should be one of the priority issues for stakeholders in the near future in disaster risk reduction. Providing equal access to resources to population in the rural community after the extreme weather event has to be the priority task for policy makers and all actors in emergency management.

  14. 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.

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

    Directory of Open Access Journals (Sweden)

    Alana Hansen

    2013-07-01

    Full Text Available Background: 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. Objective: 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. Design: Drawing upon literary sources, the authors provide commentary on this important, yet poorly understood area of heat research. Results: 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. Conclusion: 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.

  16. Granularity and textural analysis as a proxy for extreme wave events in southeast coast of India

    Indian Academy of Sciences (India)

    C S Vijaya Lakshmi; P Srinivasan; S G N Murthy; Deshraj Trivedi; Rajesh R Nair

    2010-06-01

    Extreme wave events of 1000 and 1500 years (radiocarbon ages) have been recently reported in Mahabalipuram region, southeast coast of India. Subsequently, we carried out extensive sedimentological analysis in regions covering a total lateral coverage of 12 km with a new archeological site as the central portion of the study area. Twelve trenches in shore normal profiles exhibit landward thinning sequences as well as upward fining sequences confirming with the global signatures of extreme wave events. The sediment size ranges from fine-to-medium and moderately well sorted-to-well sorted, and exhibit positive skewness with platykurtic-to-leptokurtic nature. We now propose the abrupt winnowing or back and forth motion including unidirectional transport of these deposited sediments, which results in positive skewness. Textural analyses derived from scanning electron microscope studies (SEM) demonstrate the alteration produced, in the ilmenite mineral with vivid presence of pits and crescents with deformation observed on the surface due to extreme wave activities. This is further confirmed with the predominance of high-density mineral such as magnetite (5.2) and other heavy minerals in these deposits inferred the high-intensity of the reworking process of the beach shelf sediments.

  17. On the use of ocean-atmosphere-wave models during an extreme CAO event: the importance of being coupled

    Science.gov (United States)

    Carniel, Sandro; Barbariol, Francesco; Benetazzo, Alvise; Bonaldo, Davide; Falcieri, Francesco M.; Miglietta, Mario M.; Ricchi, Antonio; Sclavo, Mauro

    2015-04-01

    During winter 2012 an extreme meteorological event stroke the whole Europe and particularly its central-southern sector. A strong and persistent spit of cold air coming from Siberian region (a Cold Air Outbreak, CAO) insisted on northern Italy and the Adriatic sea basin, leading to decreases in the sea temperatures up to 6 °C in less than two weeks, ice formation on the Venice lagoon and an exceptional snow fall in the Apennine region. In the sea the CAO was associated to a significant episode of dense water formation (DWF), a crucial phenomenon that heavily impacts the whole Adriatic Sea (from the sinking of water masses and associated ventilation of the northernmost shelf, to the flow along the western coast, until the flushing of southern Adriatic open slope and submarine canyons, with associated sediment transport and bottom reshaping). The extent of the DWF event in the Northern Adriatic sub-basin was estimated by means of coastal observatories, ad hoc measurements and, until now, results from existing one-way coupled atmosphere-ocean models. These are characterized by no SST feedback from the ocean to the atmosphere, and therefore by turbulent heat fluxes that may heavily reflect a non-consistent ocean state. The study proposes an investigation of the 2012 CAO using a fully coupled, three components, ocean-atmosphere-wave system (COAWST). Results highlight that, although the energy interplays between air and sea do not seem to significantly impact the wind forecasts, when providing heat fluxes that are consistent with the ocean temperature we find modified heat fluxes and air sea temperatures figures. Moreover, the consistent description of thermal exchanges adopted in the fully coupled model can affect the basin circulation, the quantification of dense water produced mass, and the description of its migration pathways and rates of off-shelf descent.

  18. An extreme internal solitary wave event observed in the northern South China Sea

    Science.gov (United States)

    Huang, Xiaodong; Chen, Zhaohui; Zhao, Wei; Zhang, Zhiwei; Zhou, Chun; Yang, Qingxuan; Tian, Jiwei

    2016-07-01

    With characteristics of large amplitude and strong current, internal solitary wave (ISW) is a major hazard to marine engineering and submarine navigation; it also has significant impacts on marine ecosystems and fishery activity. Among the world oceans, ISWs are particular active in the northern South China Sea (SCS). In this spirit, the SCS Internal Wave Experiment has been conducted since March 2010 using subsurface mooring array. Here, we report an extreme ISW captured on 4 December 2013 with a maximum amplitude of 240 m and a peak westward current velocity of 2.55 m/s. To the authors’ best knowledge, this is the strongest ISW of the world oceans on record. Full-depth measurements also revealed notable impacts of the extreme ISW on deep-ocean currents and thermal structures. Concurrent mooring measurements near Batan Island showed that the powerful semidiurnal internal tide generation in the Luzon Strait was likely responsible for the occurrence of the extreme ISW event. Based on the HYCOM data-assimilation product, we speculate that the strong stratification around Batan Island related to the strengthening Kuroshio may have contributed to the formation of the extreme ISW.

  19. Extreme weather event in spring 2013 delayed breeding time of Great Tit and Blue Tit.

    Science.gov (United States)

    Glądalski, Michał; Bańbura, Mirosława; Kaliński, Adam; Markowski, Marcin; Skwarska, Joanna; Wawrzyniak, Jarosław; Zieliński, Piotr; Bańbura, Jerzy

    2014-12-01

    The impact of climatic changes on life cycles by re-scheduling the timing of reproduction is an important topic in studies of biodiversity. Global warming causes and will probably cause in the future not only raising temperatures but also an increasing frequency of extreme weather events. In 2013, the winter in central and north Europe ended late, with low temperatures and long-retained snow cover--this extreme weather phenomenon acted in opposition to the increasing temperature trend. In 2013, thermal conditions measured by the warmth sum in the period 15 March–15 April, a critical time for early breeding passerines, went far beyond the range of the warmth sums for at least 40 preceding years. Regardless of what was the reason for the extreme early spring 2013 and assuming that there is a potential for more atypical years because of climate change, we should look closely at every extreme phenomenon and its consequences for the phenology of organisms. In this paper, we report that the prolonged occurrence of winter conditions during the time that is crucial for Blue Tit (Cyanistes caeruleus) and Great Tit (Parus major) reproduction caused a substantial delay in the onset of egg laying in comparison with typical springs.

  20. Extreme and superextreme events in a loss-modulated CO2 laser: Nonlinear resonance route and precursors

    Science.gov (United States)

    Bonatto, Cristian; Endler, Antonio

    2017-07-01

    We investigate the occurrence of extreme and rare events, i.e., giant and rare light pulses, in a periodically modulated CO2 laser model. Due to nonlinear resonant processes, we show a scenario of interaction between chaotic bands of different orders, which may lead to the formation of extreme and rare events. We identify a crisis line in the modulation parameter space, and we show that, when the modulation amplitude increases, remaining in the vicinity of the crisis, some statistical properties of the laser pulses, such as the average and dispersion of amplitudes, do not change much, whereas the amplitude of extreme events grows enormously, giving rise to extreme events with much larger deviations than usually reported, with a significant probability of occurrence, i.e., with a long-tailed non-Gaussian distribution. We identify recurrent regular patterns, i.e., precursors, that anticipate the emergence of extreme and rare events, and we associate these regular patterns with unstable periodic orbits embedded in a chaotic attractor. We show that the precursors may or may not lead to the emergence of extreme events. Thus, we compute the probability of success or failure (false alarm) in the prediction of the extreme events, once a precursor is identified in the deterministic time series. We show that this probability depends on the accuracy with which the precursor is identified in the laser intensity time series.

  1. Extreme heat and cultural and linguistic minorities in Australia: perceptions of stakeholders

    Science.gov (United States)

    2014-01-01

    Background Despite acclimatisation to hot weather, many individuals in Australia are adversely affected by extreme heat each summer, placing added pressure on the health sector. In terms of public health, it is therefore important to identify vulnerable groups, particularly in the face of a warming climate. International evidence points to a disparity in heat-susceptibility in certain minority groups, although it is unknown if this occurs in Australia. With cultural diversity increasing, the aim of this study was to explore how migrants from different cultural backgrounds and climate experiences manage periods of extreme heat in Australia. Methods A qualitative study was undertaken across three Australian cities, involving interviews and focus groups with key informants including stakeholders involved in multicultural service provision and community members. Thematic analysis and a framework approach were used to analyse the data. Results Whilst migrants and refugees generally adapt well upon resettlement, there are sociocultural barriers encountered by some that hinder environmental adaptation to periods of extreme heat in Australia. These barriers include socioeconomic disadvantage and poor housing, language barriers to the access of information, isolation, health issues, cultural factors and lack of acclimatisation. Most often mentioned as being at risk were new arrivals, people in new and emerging communities, and older migrants. Conclusions With increasing diversity within populations, it is important that the health sector is aware that during periods of extreme heat there may be disparities in the adaptive capacity of minority groups, underpinned by sociocultural and language-based vulnerabilities in migrants and refugees. These factors need to be considered by policymakers when formulating and disseminating heat health strategies. PMID:24889099

  2. Ecological Responses to Extreme Flooding Events: A Case Study with a Reintroduced Bird.

    Science.gov (United States)

    Soriano-Redondo, Andrea; Bearhop, Stuart; Cleasby, Ian R; Lock, Leigh; Votier, Stephen C; Hilton, Geoff M

    2016-06-27

    In recent years numerous studies have documented the effects of a changing climate on the world's biodiversity. Although extreme weather events are predicted to increase in frequency and intensity and are challenging to organisms, there are few quantitative observations on the survival, behaviour and energy expenditure of animals during such events. We provide the first data on activity and energy expenditure of birds, Eurasian cranes Grus grus, during the winter of 2013-14, which saw the most severe floods in SW England in over 200 years. We fitted 23 cranes with telemetry devices and used remote sensing data to model flood dynamics during three consecutive winters (2012-2015). Our results show that during the acute phase of the 2013-14 floods, potential feeding areas decreased dramatically and cranes restricted their activity to a small partially unflooded area. They also increased energy expenditure (+15%) as they increased their foraging activity and reduced resting time. Survival did not decline in 2013-14, indicating that even though extreme climatic events strongly affected time-energy budgets, behavioural plasticity alleviated any potential impact on fitness. However under climate change scenarios such challenges may not be sustainable over longer periods and potentially could increase species vulnerability.

  3. 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.

  4. Recovery trends of Scrobicularia plana populations after restoration measures, affected by extreme climate events.

    Science.gov (United States)

    Verdelhos, T; Cardoso, P G; Dolbeth, M; Pardal, M A

    2014-07-01

    The Mondego estuary (Portugal) went through different ecological scenarios over the last decades. An eutrophication process led to a decline in the ecosystem quality. The ensuing restoration plan resulted into a gradual ecological recovery, which was impaired by the occurrence of successive extreme climate events that affected dynamics and productivity of key species. In this study we assess the response of the bivalve Scrobicularia plana to the impacts of these events in a recovery scenario, by comparing populations in two different intertidal habitats: a seagrass bed and a sandflat area. As a general tendency, S. plana, which was negatively affected by eutrophication, responded positively to restoration. However, the occurrence of extreme climate events seemed to affect recruitment success, biomass and production, impairing the recovery process. In the seagrass bed, S. plana maintained a stable and structured population, while in the sandflat area recovery clearly reverted into a decline, mainly concerning biomass and production values. This sequence of multiple stressors might have reduced S. plana resilience to further impacts and therefore, understanding the behavior of biological populations following restoration initiatives requires acknowledgement that some changes may not be easily reversible.

  5. 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.

  6. The differential effects of increasing frequency and magnitude of extreme events on coral populations.

    Science.gov (United States)

    Fabina, Nicholas S; Baskett, Marissa L; Gross, Kevin

    2015-09-01

    Extreme events, which have profound ecological consequences, are changing in both frequency and magnitude with climate change. Because extreme temperatures induce coral bleaching, we can explore the relative impacts of changes in frequency and magnitude of high temperature events on coral reefs. Here, we combined climate projections and a dynamic population model to determine how changing bleaching regimes influence coral persistence. We additionally explored how coral traits and competition with macroalgae mediate changes in bleaching regimes. Our results predict that severe bleaching events reduce coral persistence more than frequent bleaching. Corals with low adult mortality and high growth rates are successful when bleaching is mild, but bleaching resistance is necessary to persist when bleaching is severe, regardless of frequency. The existence of macroalgae-dominated stable states reduces coral persistence and changes the relative importance of coral traits. Building on previous studies, our results predict that management efforts may need to prioritize protection of "weaker" corals with high adult mortality when bleaching is mild, and protection of "stronger" corals with high bleaching resistance when bleaching is severe. In summary, future reef projections and conservation targets depend on both local bleaching regimes and biodiversity.

  7. 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.

  8. Application of a Coupled WRF-Hydro Model for Extreme Flood Events in the Mediterranean Basins

    Science.gov (United States)

    Fredj, Erick; Givati, Amir

    2015-04-01

    More accurate simulation of precipitation and streamflow is a challenge that can be addressed by using the Weather Research and Forecasting Model (WRF) in conjunction with the hydrological model coupling extension package (WRF-Hydro).This is demonstrated for the country of Israel and surrounding regions. Simulations from the coupled WRF/WRF-Hydro system were verified against measurements from rain gauges and hydrometric stations in the domain for the 2012-2013 and 2013-2014 winters (wet seasons). These periods were characterized by many punctuated hydrometeorological and hydroclimatic events, including both severe drought and extreme floods events. The WRF model simulations were initialized with 0.5 degree NOAA/NCEP GFS model data. The model domain was set up with 3 domains, up to 3km grid spacing resolution. The model configuration used here constitutes a fully distributed, 3-dimensional, variably-saturated surface and subsurface flow model. Application of terrain routing and, subsequently, channel and reservoir routing functions, to the uni-dimensional NOAA land surface model was motivated by the need to account for increased complexity in land surface states and fluxes and to provide a more physically-realistic conceptualization of terrestrial hydrologic processes. The simulation results indicated a good agreement with actual peak discharges for extreme flood events and for full hydrographs. Specifically the coupled WRF/WRF-Hydro model as configured in this study shows improvement in simulated precipitation over one way WRF precipitation simulations. The correlation between the observed and the simulated precipitation using the fully coupled WRF/WRF-Hydro system was higher than the standalone WRF model, especially for convective precipitation events that affect arid regions in the domain. The results suggest that the coupled WRF/WRF-Hydro system has potential for flood forecasting and flood warning purposes at 0-72 hour lead times for large cool season storm

  9. Forecasting extreme events in collective dynamics: an analytic signal approach to detecting discrete scale invariance

    CERN Document Server

    Viswanathan, G M

    2006-01-01

    A challenging problem in physics concerns the possibility of forecasting rare but extreme phenomena such as large earthquakes, financial market crashes, and material rupture. A promising line of research involves the early detection of precursory log-periodic oscillations to help forecast extreme events in collective phenomena where discrete scale invariance plays an important role. Here I investigate two distinct approaches towards the general problem of how to detect log-periodic oscillations in arbitrary time series without prior knowledge of the location of the moveable singularity. I first show that the problem has a definite solution in Fourier space, however the technique involved requires an unrealistically large signal to noise ratio. I then show that the quadrature signal obtained via analytic continuation onto the imaginary axis, using the Hilbert transform, necessarily retains the log-periodicities found in the original signal. This finding allows the development of a new method of detecting log-p...

  10. LISA extreme-mass-ratio inspiral events as probes of the black hole mass function

    CERN Document Server

    Gair, Jonathan R; Volonteri, Marta

    2010-01-01

    One of the sources of gravitational waves for the proposed space-based gravitational wave detector, the Laser Interferometer Space Antenna (LISA), are the inspirals of compact objects into supermassive black holes in the centres of galaxies - extreme-mass-ratio inspirals (EMRIs). Using LISA observations, we will be able to measure the parameters of each EMRI system detected to very high precision. However, the statistics of the set of EMRI events observed by LISA will be more important in constraining astrophysical models than extremely precise measurements for individual systems. The black holes to which LISA is most sensitive are in a mass range that is difficult to probe using other techniques, so LISA provides an almost unique window onto these objects. In this paper we explore, using Bayesian techniques, the constraints that LISA EMRI observations can place on the mass function of black holes at low redshift. We describe a general framework for approaching inference of this type --- using multiple observ...

  11. Uncertainty assessment in the prediction of extreme rainfall events: an example from the central Spanish Pyrenees

    Science.gov (United States)

    García-Ruiz, J. M.; Arnáez, J.; White, S. M.; Lorente, A.; Beguería, S.

    2000-04-01

    Extreme rainfall events occur frequently in the central Pyrenees, but they are responsible for mass movements and short, very intense erosion periods, accompanied at times by loss of human life and high costs of infrastructure. This paper tries to assess the existence of patterns in the spatial distribution of maximum precipitation. The calculation of return periods of the most intense rainfall demonstrates that in the Pyrenees it exhibits an erratic spatial and temporal distribution and can be extremely localized. In the case of precipitation between 150 and 200 mm in 24 h, some influence from the surrounding relief has been found, but this is not the case for precipitation exceeding 200 mm, characterized by the absence of patterns governing their spatial distribution. Geomorphological approaches are, therefore, the only way for assessing the areas more subject to hydromorphological risks.

  12. Extreme precipitation events in the Iberian Peninsula and its association with Atmospheric Rivers

    Science.gov (United States)

    Ramos, Alexandre M.; Liberato, Margarida L. R.; Trigo, Ricardo M.

    2015-04-01

    Extreme precipitation events in the Iberian Peninsula during the winter half of the year have major socio-economic impacts associated with floods, landslides, extensive property damage and life losses. In recent years, a number of works have shed new light on the role played by Atmospheric Rivers (ARs) in the occurrence of extreme precipitation events in both Europe and USA. ARs are relatively narrow regions of concentrated WV responsible for horizontal transport in the lower atmosphere corresponding to the core section of the broader warm conveyor belt occurring over the oceans along the warm sector of extra-tropical cyclones. Over the North Atlantic ARs are usually W-E oriented steered by pre-frontal low level jets along the trailing cold front and subsequently feed the precipitation in the extra-tropical cyclones. It was shown that more than 90% of the meridional WV transport in the mid-latitudes occurs in the AR, although they cover less than 10% of the area of the globe. The large amount of WV that is transported can lead to heavy precipitation and floods. An automated ARs detection algorithm is used for the North Atlantic Ocean Basin allowing the identification and a comprehensive characterization of the major AR events that affected the Iberian Peninsula over the 1948-2012 period. The extreme precipitation days in the Iberian Peninsula were assessed recently by us (Ramos et al., 2014) and their association (or not) with the occurrence of AR is analyzed in detail here. The extreme precipitation days are ranked by their magnitude and are obtained after considering 1) the area affected and 2) the precipitation intensity. Different rankings are presented for the entire Iberian Peninsula, Portugal and also for the six largest Iberian river basins (Minho, Duero, Tagus, Guadiana, Guadalquivir and Ebro) covering the 1950-2008 period (Ramos et al., 2014). Results show that the association between ARs and extreme precipitation days in the western domains (Portugal

  13. Impacts of extreme events of drought and flood on local communities of Amazon basin

    Science.gov (United States)

    Borma, L. D.; Roballo, S.; Zauner, M.; Nascimento, V. F.

    2013-05-01

    The analysis of drought events of 1997/98, 2005 and 2010 in terms of discharge anomalies in the Amazon region confirmed previous findings, such as: a) the influence of the El Niño in more than one hydrological year; b) the increase of the influence of the Atlantic Multidecadal Oscillation of 1998, 2005 and 2010 drought events; c) the low levels of discharge observed in the 2010 drought are attributed to the association of discharge anomalies of the northern and southern tributaries of the Amazon river, and d) the 2010 drought lasted around 1 month (August to November) more than the other drought events analized here. The riverine communities located along the river banks of Solimões/Amazonas suit their economic activities to the oscillation of the water level. In general, low water periods favor the access to important sources of food such as fish and livestock, still allowing crop cultivation on fertile agricultural areas of the floodplain. Conversely, periods of drought increases the difficulties of transport and drinking water supply. During the high water, access to the main food supply (described above) are greatly hampered. However, the floods are recognized as an importance process of natural fertilization. Thus, despite the political, social and economic shortcomings, the local community has, since the pre-colonial period, learned to get the best of each season, providing local, regional and national markets with varzea products. During periods of extreme weather, however, the advantages of each season appear to be reduced, and the drawbacks increased. In fact, during flooding extremes, the access to primary sources of food is hampered by a long period of time and families find themselves forced to leave their homes, eventually losing them. Analysis of flow data to the extreme flooding of 2009, indicate a period of about 6 months of positive anomalies discharge (occurring mainly during high water). At the same time, Civil Defense data points to a

  14. Characteristics of extreme dust events observed over two urban areas in Iran

    Indian Academy of Sciences (India)

    Abbas-Ali A Bidokhti; Maryam Gharaylou; Nafiseh Pegahfar; Samaneh Sabetghadam; Maryam Rezazadeh

    2016-03-01

    Determination of dust loading in the atmosphere is important not only from the public health point of view, but also for regional climate changes. The present study focuses on the characteristics of two major dust events for two urban areas in Iran, Kermanshah and Tehran, over the period of 4 years from 2006 to 2009. To detect extreme dust outbreaks, various datasets including synoptic data, dust concentration, reanalysis data and numerical results of WRF and HYSPLIT models were used. The weather maps demonstrate that for these events dusts are mainly generated when wind velocity is high and humidity islow in the lower troposphere and the region is under the influence of a thermal low. The event lasts until the atmospheric stability prevails and the surface wind speed weakens. The thermal low nature of the synoptic conditions of these major events is also responsible for deep boundary layer development with its thermals affecting the vertical dust flux over the region. Trajectory studies show that the dust events originated from deserts in Iraq and Syria and transported towards Iran. The main distinction between the two types of mobilizations seems to affect the dust concentrations in the Tehran urban area.

  15. Intensity changes in future extreme precipitation: A statistical event-based approach.

    Science.gov (United States)

    Manola, Iris; van den Hurk, Bart; de Moel, Hans; Aerts, Jeroen

    2017-04-01

    Short-lived precipitation extremes are often responsible for hazards in urban and rural environments with economic and environmental consequences. The precipitation intensity is expected to increase about 7% per degree of warming, according to the Clausius-Clapeyron (CC) relation. However, the observations often show a much stronger increase in the sub-daily values. In particular, the behavior of the hourly summer precipitation from radar observations with the dew point temperature (the Pi-Td relation) for the Netherlands suggests that for moderate to warm days the intensification of the precipitation can be even higher than 21% per degree of warming, that is 3 times higher than the expected CC relation. The rate of change depends on the initial precipitation intensity, as low percentiles increase with a rate below CC, the medium percentiles with 2CC and the moderate-high and high percentiles with 3CC. This non-linear statistical Pi-Td relation is suggested to be used as a delta-transformation to project how a historic extreme precipitation event would intensify under future, warmer conditions. Here, the Pi-Td relation is applied over a selected historic extreme precipitation event to 'up-scale' its intensity to warmer conditions. Additionally, the selected historic event is simulated in the high-resolution, convective-permitting weather model Harmonie. The initial and boundary conditions are alternated to represent future conditions. The comparison between the statistical and the numerical method of projecting the historic event to future conditions showed comparable intensity changes, which depending on the initial percentile intensity, range from below CC to a 3CC rate of change per degree of warming. The model tends to overestimate the future intensities for the low- and the very high percentiles and the clouds are somewhat displaced, due to small wind and convection changes. The total spatial cloud coverage in the model remains, as also in the statistical

  16. Modernizing Distribution System Restoration to Achieve Grid Resiliency Against Extreme Weather Events: An Integrated Solution

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chen; Wang, Jianhui; Ton, Dan

    2017-07-01

    Recent severe power outages caused by extreme weather hazards have highlighted the importance and urgency of improving the resilience of the electric power grid. As the distribution grids still remain vulnerable to natural disasters, the power industry has focused on methods of restoring distribution systems after disasters in an effective and quick manner. The current distribution system restoration practice for utilities is mainly based on predetermined priorities and tends to be inefficient and suboptimal, and the lack of situational awareness after the hazard significantly delays the restoration process. As a result, customers may experience an extended blackout, which causes large economic loss. On the other hand, the emerging advanced devices and technologies enabled through grid modernization efforts have the potential to improve the distribution system restoration strategy. However, utilizing these resources to aid the utilities in better distribution system restoration decision-making in response to extreme weather events is a challenging task. Therefore, this paper proposes an integrated solution: a distribution system restoration decision support tool designed by leveraging resources developed for grid modernization. We first review the current distribution restoration practice and discuss why it is inadequate in response to extreme weather events. Then we describe how the grid modernization efforts could benefit distribution system restoration, and we propose an integrated solution in the form of a decision support tool to achieve the goal. The advantages of the solution include improving situational awareness of the system damage status and facilitating survivability for customers. The paper provides a comprehensive review of how the existing methodologies in the literature could be leveraged to achieve the key advantages. The benefits of the developed system restoration decision support tool include the optimal and efficient allocation of repair

  17. Extreme Events in the tropics - Hurricane Manuel and La Pintada Landslide

    Science.gov (United States)

    Ramirez-Herrera, M. T.; Gaidzik, K.

    2016-12-01

    Extreme events in regions of humid-warm tropical climate are repeatedly causing loss of life and economic devastation. Deadly landslides are commonly triggered by extreme storms. Many of them originate on mountain slopes along river systems in areas often populated, increasing the risk to human settlements, theirs activities, and the local envrionment. Frequently hit by hurricanes and tropical cyclones the mountainous areas of Guerrero in southern Mexico are particularly prone to landslide hazard. On 16 September 2013 a huge landslide caused 71 fatalities and destroyed a large part of the La Pintada village. The landslide initiated after extreme rainfall caused by Hurricane Manuel. We performed a post-landslide field survey, applied remote sensing techniques using LIDAR DEM and images, digital models derived from Structure from Motion (SfM), satellite images, orthophotomaps, eyewitness accounts, geotechnical laboratory tests of slope material, and slope stability analysis to examine physical characteristics and processes that influenced the failure of La Pintada landslide. Our results indicate that anomalous precipitation producing oversaturation of soil was the direct factor that initiated the deep-sited La Pintada landslide, in an area where big landslides have occurred in the past. We hypothesized that climate change has contributed to the short recurrence period of extreme meteorological events that trigger great landslides in this tropical area. The lack of high and dense vegetation on La Pintada slope, resulting in increased soil erosion, acted as a preparatory causal factor for landsliding, making the slope more prone to mass wasting. It is likely that human activity (including deforestation activities) also contributed to the decrease of slope stability by cutting the toe of the slope to build houses. Seismic activity, even if did not contribute directly to the initiation of the La Pintada landslide, might have promoted the decrease in slope stability in

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

    Science.gov (United States)

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

    2017-01-01

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

  19. Recurring features of extreme rainfall events close to Veneto coast during autumn

    Science.gov (United States)

    Monai, M.; Barbi, A.; Racca, R.

    2010-09-01

    Climate of Veneto (north-east Italy) is characterized by significant differences between specific areas: mountains, plane, coast, etc. Such differences are particulary strong as far as precipitation is concerned. Mean annual rainfall on the coast is approximately 700-1000mm, whereas quantities more than double are measured on Prealps, only 100 km apart. Such differences are mainly related to crucial role of reliefs and with their interaction with southerly warm and humid fluxis coming from the Mediterranean Sea. A more detailed analyses of rainfall distribution highlights some interesting features, associated with a more localized role of the Adriatic Sea. Among others, it is noticeable that coastal area of Veneto is well subject to extreme events even if, as already mentioned, total annual amount of rain is the lowest in the region. Referring to the coast of Veneto, present work deals with: a) Climate study including seasonal and monthly distributions of precipitation; b) Contribution of extreme events to annual total; c) Analyses of recent extreme events happened in September during last four years. In fact for that area of Veneto, September is the most rainy month. Furthermore during September maximum of daily rainfall values were recorded (period of analyses 1993-2009); in particular, during the last four months of September, from 2006 to 2009, every year an extreme event occurred. Final goal was to understand main factors that caused such particular episodes in the same period of the year. Referring to four recent events happened during last four months of September, a detailed analyses was carried out including: - synoptic analyses both at surface than aloft; - study on mesoscale information derived from ground dense network, weather radar, etc. All events evidenced some common features: - deep thought aloft between North Atlantic Ocean and Central Mediterranean, with possible formation of low-level cyclone on Gulf of Genoa; - low-level advection of moist and

  20. OCCURRENCE OF EXTREME SOLAR PARTICLE EVENTS: ASSESSMENT FROM HISTORICAL PROXY DATA

    Energy Technology Data Exchange (ETDEWEB)

    Usoskin, Ilya G. [Sodankylae Geophysical Observatory (Oulu unit) and Department of Physical Sciences, University of Oulu, FIN-90014 Oulu (Finland); Kovaltsov, Gennady A., E-mail: ilya.usoskin@oulu.fi [Ioffe Physical-Technical Institute of RAS, 194021 St. Petersburg (Russian Federation)

    2012-09-20

    The probability of occurrence of extreme solar particle events (SPEs) with proton fluence (>30 MeV) F{sub 30} {>=} 10{sup 10} cm{sup -2} is evaluated based on data on the cosmogenic isotopes {sup 14}C and {sup 10}Be in terrestrial archives covering centennial-millennial timescales. Four potential candidates with F{sub 30} = (1-1.5) Multiplication-Sign 10{sup 10} cm{sup -2} and no events with F{sub 30} > 2 Multiplication-Sign 10{sup 10} cm{sup -2} are identified since 1400 AD in the annually resolved {sup 10}Be data. A strong SPE related to the Carrington flare of 1859 AD is not supported by the data. For the last 11,400 years, 19 SPE candidates with F{sub 30} = (1-3) Multiplication-Sign 10{sup 10} cm{sup -2} are found and clearly no event with F{sub 30} > 5 Multiplication-Sign 10{sup 10} cm{sup -2} (50 times the SPE of 1956 February 23) has occurred. These values serve as observational upper limits on the strength of SPEs on the timescale of tens of millennia. Two events, ca. 780 and 1460 AD, appear in different data series making them strong candidates for extreme SPEs. We build a distribution of the occurrence probability of extreme SPEs, providing a new strict observational constraint. Practical limits can be set as F{sub 30} Almost-Equal-To 1, 2-3, and 5 Multiplication-Sign 10{sup 10} cm{sup -2} for occurrence probabilities Almost-Equal-To 10{sup -2}, 10{sup -3}, and 10{sup -4} yr{sup -1}, respectively. Because of the uncertainties, our results should be interpreted as a conservative upper limit on the SPE occurrence near Earth. The mean solar energetic particle (SEP) flux is evaluated as Almost-Equal-To 40 (cm{sup 2} s){sup -1}, in agreement with estimates from lunar rocks. On average, extreme SPEs contribute about 10% to the total SEP fluence.

  1. Comparison of annual maximum series and partial duration series methods for modeling extreme hydrologic events

    DEFF Research Database (Denmark)

    Madsen, Henrik; Pearson, Charles P.; Rosbjerg, Dan

    1997-01-01

    Two regional estimation schemes, based on, respectively, partial duration series (PDS) and annual maximum series (AMS), are compared. The PDS model assumes a generalized Pareto (GP) distribution for modeling threshold exceedances corresponding to a generalized extreme value (GEV) distribution...... for annual maxima. First, the accuracy of PDS/GP and AMS/GEV regional index-flood T-year event estimators are compared using Monte Carlo simulations. For estimation in typical regions assuming a realistic degree of heterogeneity, the PDS/GP index-flood model is more efficient. The regional PDS and AMS...

  2. Cosmic rays Monte Carlo simulations for the Extreme Energy Events Project

    CERN Document Server

    Abbrescia, M; Aiola, S; Antolini, R; Avanzini, C; Baldini Ferroli, R; Bencivenni, G; Bossini, E; Bressan, E; Chiavassa, A; Cicalò, C; Cifarelli, L; Coccia, E; De Gruttola, D; De Pasquale, S; Di Giovanni, A; D'Incecco, M; Dreucci, M; Fabbri, F L; Frolov, V; Garbini, M; Gemme, G; Gnesi, I; Gustavino, C; Hatzifotiadou, D; La Rocca, P; Li, S; Librizzi, F; Maggiora, A; Massai, M; Miozzi, S; Panareo, M; Paoletti, R; Perasso, L; Pilo, F; Piragino, G; Regano, A; Riggi, F; Righini, G C; Sartorelli, G; Scapparone, E; Scribano, A; Selvi, M; Serci, S; Siddi, E; Spandre, G; Squarcia, S; Taiuti, M; Tosello, F; Votano, L; Williams, M C S; Yánez, G; Zichichi, A; Zuyeuski, R

    2014-01-01

    The Extreme Energy Events Project (EEE Project) is an innovative experiment to study very high energy cosmic rays by means of the detection of the associated air shower muon component. It consists of a network of tracking detectors installed inside Italian High Schools. Each tracking detector, called EEE telescope, is composed of three Multigap Resistive Plate Chambers (MRPCs). At present, 43 telescopes are installed and taking data, opening the way for the detection of far away coincidences over a total area of about 3 × 10 5 km 2 . In this paper we present the Monte Carlo simulations that have been performed to predict the expected coincidence rate between distant EEE telescopes.

  3. Two centuries of extreme events over the Baltic Sea and North Sea regions

    Science.gov (United States)

    Stendel, Martin; den Besselaar Else, van; Abdel, Hannachi; Jaak, Jaagus; Elizabeth, Kent; Christiana, Lefebvre; Gudrun, Rosenhagen; Anna, Rutgersson; Frederik, Schenk; der Schrier Gerard, van; Tim, Woolings

    2017-04-01

    Two centuries of extreme events over the Baltic Sea and North Sea regions In the framework of the BACC 2 (for the Baltic Sea) and NOSCCA projects (for the North Sea region), studies of past and present variability and changes in atmospheric variables within the North Sea region over the instrumental period (roughly the past 200 years) have been investigated. Findings on trends in temperature and precipitation have already been presented. Here we focus on data homogeneity issues and examine how reliable reanalyses are in this context. Unlike most other regions in the world, there is a wealth of old observations available for the Baltic and North Sea regions, most of it in handwritten form in meteorological journals and other publications. These datasets need to be carefully digitised and homogenized. For this, a thorough quality control must be applied; otherwise the digitised datasets may prove useless or even counterproductive. We present evidence that this step cannot be conducted without human interference and thus cannot be fully automated. Furthermore, inhomogeneities due to e.g. instrumentation and station relocations need to be addressed. A wealth of reanalysis products is available, which can help detect such inhomogeneities in observed time series, but at the same time are prone to biases and/or spurious trends themselves e.g. introduced by changes in the availability and quality of the underlying assimilated data. It therefore in general remains unclear in how far we can simulate the pre-satellite era with respect to homogeneity with reanalyses based only on parts of the observing system. Extreme events and changes in extreme situations are more important and of greater (societal) significance than changes in mean climate. However, changes in extreme weather events are difficult to assess not only because they are, per definition, rare events, but also due to the homogeneity issues outlined above. Taking these into account, we present evidence for changes

  4. Cosmic rays Monte Carlo simulations for the Extreme Energy Events Project

    Science.gov (United States)

    Abbrescia, M.; Agocs, A.; Aiola, S.; Antolini, R.; Avanzini, C.; Baldini Ferroli, R.; Bencivenni, G.; Bossini, E.; Bressan, E.; Chiavassa, A.; Cicalò, C.; Cifarelli, L.; Coccia, E.; De Gruttola, D.; De Pasquale, S.; Di Giovanni, A.; D'Incecco, M.; Dreucci, M.; Fabbri, F. L.; Frolov, V.; Garbini, M.; Gemme, G.; Gnesi, I.; Gustavino, C.; Hatzifotiadou, D.; La Rocca, P.; Li, S.; Librizzi, F.; Maggiora, A.; Massai, M.; Miozzi, S.; Panareo, M.; Paoletti, R.; Perasso, L.; Pilo, F.; Piragino, G.; Regano, A.; Riggi, F.; Righini, G. C.; Sartorelli, G.; Scapparone, E.; Scribano, A.; Selvi, M.; Serci, S.; Siddi, E.; Spandre, G.; Squarcia, S.; Taiuti, M.; Tosello, F.; Votano, L.; Williams, M. C. S.; Yánez, G.; Zichichi, A.; Zuyeuski, R.

    2014-08-01

    The Extreme Energy Events Project (EEE Project) is an innovative experiment to study very high energy cosmic rays by means of the detection of the associated air shower muon component. It consists of a network of tracking detectors installed inside Italian High Schools. Each tracking detector, called EEE telescope, is composed of three Multigap Resistive Plate Chambers (MRPCs). At present, 43 telescopes are installed and taking data, opening the way for the detection of far away coincidences over a total area of about 3 × 105 km2. In this paper we present the Monte Carlo simulations that have been performed to predict the expected coincidence rate between distant EEE telescopes.

  5. Crossing historical and sedimentary archives to reconstruct an extreme flood event calendar in high alpine areas

    Science.gov (United States)

    Wilhelm, B.; Giguet-Covex, C.; Arnaud, F.; Allignol, F.; Legaz, A.; Melo, A.

    2010-09-01

    to reconstruct a high-resolution flood calendar to assess a reliable frequency of extreme flood events which can be compared with precise climatic parameters as the instrumental and reconstructed temperature. Finally it was equally possible to compare the recorded intensity of flood events between the both archives and thus estimate the hazard perception and vulnerability of local people throughout the last three centuries.

  6. A study of upward going particles with the Extreme Energy Events telescopes

    Energy Technology Data Exchange (ETDEWEB)

    Abbrescia, M. [Museo Storico della Fisica e Centro Studi e Ricerche E. Fermi, Roma (Italy); INFN and Dipartimento di Fisica, Università di Bari, Bari (Italy); Avanzini, C.; Baldini, L. [Museo Storico della Fisica e Centro Studi e Ricerche E. Fermi, Roma (Italy); INFN and Dipartimento di Fisica, Università di Pisa, Pisa (Italy); Ferroli, R. Baldini [Museo Storico della Fisica e Centro Studi e Ricerche E. Fermi, Roma (Italy); INFN Laboratori Nazionali di Frascati, Frascati (RM) (Italy); Batignani, G. [Museo Storico della Fisica e Centro Studi e Ricerche E. Fermi, Roma (Italy); INFN and Dipartimento di Fisica, Università di Pisa, Pisa (Italy); Bencivenni, G. [INFN Laboratori Nazionali di Frascati, Frascati (RM) (Italy); Bossini, E. [Museo Storico della Fisica e Centro Studi e Ricerche E. Fermi, Roma (Italy); INFN Gruppo Collegato di Siena and Dipartimento di Fisica, Università di Siena, Siena (Italy); Chiavassa, A. [INFN and Dipartimento di Fisica, Università di Torino, Torino (Italy); Cicalo, C. [Museo Storico della Fisica e Centro Studi e Ricerche E. Fermi, Roma (Italy); INFN and Dipartimento di Fisica, Università di Cagliari, Cagliari (Italy); Cifarelli, L. [Museo Storico della Fisica e Centro Studi e Ricerche E. Fermi, Roma (Italy); INFN and Dipartimento di Fisica, Università di Bologna, Bologna (Italy); Coccia, E. [INFN and Dipartimento di Fisica, Università di Roma Tor Vergata, Roma (Italy); Corvaglia, A. [Museo Storico della Fisica e Centro Studi e Ricerche E. Fermi, Roma (Italy); INFN and Dipartimento di Matematica e Fisica, Università del Salento, Lecce (Italy); and others

    2016-04-21

    In this paper the first study of the upward going events detected by the telescopes of the Extreme Energy Event (EEE) project is reported. The EEE project consists of a detector array of Multigap Resistive Plate Chambers located at selected sites on the Italian territory. During autumn 2014 the first coordinated data taking period took place and around one billion candidate tracks were collected. Among them, of particular interest is the sample of particles which cross the telescopes from below. The results obtained demonstrate that the EEE telescopes can distinguish the electrons produced as decay products of cosmic muons stopped in the ground, or in the last chamber of the telescopes themselves, confirming the excellent performance of the system for the investigation of intriguing cosmic phenomena.

  7. CrossRef A study of upward going particles with the Extreme Energy Events telescopes

    CERN Document Server

    Abbrescia, M; Baldini, L; Ferroli, R Baldini; Batignani, G; Bencivenni, G; Bossini, E; Chiavassa, A; Cicalo, C; Cifarelli, L; Coccia, E; Corvaglia, A; De Gruttola, D; De Pasquale, S; Di Giovanni, A; D׳Incecco, M; Dreucci, M; Fabbri, F L; Fattibene, E; Ferraro, A; Forster, R; Frolov, V; Galeotti, P; Garbini, M; Gemme, G; Gnesi, I; Grazzi, S; Gustavino, C; Hatzifotiadu, D; La Rocca, P; Maggiora, A; Maron, G; Mazziotta, M N; Miozzi, S; Nania, R; Noferini, F; Nozzoli, F; Panareo, M; Panetta, M P; Paoletti, R; Perasso, L; Pilo, F; Piragino, G; Riggi, F; Righini, G C; Rodriguez, A R; Sartorelli, G; Scapparone, E; Schioppa, M; Scribano, A; Selvi, M; Serci, S; Siddi, E; Squarcia, S; Stori, L; Taiuti, M; Terreni, G; Vistoli, M C; Votano, L; Williams, M C S; Zani, S; Zichichi, A; Zuyeuski, R

    2016-01-01

    In this paper the first study of the upward going events detected by the telescopes of the Extreme Energy Event (EEE) project is reported. The EEE project consists of a detector array of Multigap Resistive Plate Chambers located at selected sites on the Italian territory. During autumn 2014 the first coordinated data taking period took place and around one billion candidate tracks were collected. Among them, of particular interest is the sample of particles which cross the telescopes from below. The results obtained demonstrate that the EEE telescopes can distinguish the electrons produced as decay products of cosmic muons stopped in the ground, or in the last chamber of the telescopes themselves, confirming the excellent performance of the system for the investigation of intriguing cosmic phenomena.

  8. A study of upward going particles with the Extreme Energy Events telescopes

    Science.gov (United States)

    Abbrescia, M.; Avanzini, C.; Baldini, L.; Ferroli, R. Baldini; Batignani, G.; Bencivenni, G.; Bossini, E.; Chiavassa, A.; Cicalo, C.; Cifarelli, L.; Coccia, E.; Corvaglia, A.; De Gruttola, D.; De Pasquale, S.; Di Giovanni, A.; D`Incecco, M.; Dreucci, M.; Fabbri, F. L.; Fattibene, E.; Ferraro, A.; Forster, R.; Frolov, V.; Galeotti, P.; Garbini, M.; Gemme, G.; Gnesi, I.; Grazzi, S.; Gustavino, C.; Hatzifotiadu, D.; La Rocca, P.; Maggiora, A.; Maron, G.; Mazziotta, M. N.; Miozzi, S.; Nania, R.; Noferini, F.; Nozzoli, F.; Panareo, M.; Panetta, M. P.; Paoletti, R.; Perasso, L.; Pilo, F.; Piragino, G.; Riggi, F.; Righini, G. C.; Rodriguez, A. R.; Sartorelli, G.; Scapparone, E.; Schioppa, M.; Scribano, A.; Selvi, M.; Serci, S.; Siddi, E.; Squarcia, S.; Stori, L.; Taiuti, M.; Terreni, G.; Vistoli, M. C.; Votano, L.; Williams, M. C. S.; Zani, S.; Zichichi, A.; Zuyeuski, R.

    2016-04-01

    In this paper the first study of the upward going events detected by the telescopes of the Extreme Energy Event (EEE) project is reported. The EEE project consists of a detector array of Multigap Resistive Plate Chambers located at selected sites on the Italian territory. During autumn 2014 the first coordinated data taking period took place and around one billion candidate tracks were collected. Among them, of particular interest is the sample of particles which cross the telescopes from below. The results obtained demonstrate that the EEE telescopes can distinguish the electrons produced as decay products of cosmic muons stopped in the ground, or in the last chamber of the telescopes themselves, confirming the excellent performance of the system for the investigation of intriguing cosmic phenomena.

  9. New approaches for rainfall ensemble post-processing with a focus on extreme and rare events

    Science.gov (United States)

    Taillardat, Maxime; Mestre, Olivier; Fougères, Anne-Laure; Naveau, Philippe

    2017-04-01

    Ensemble forecasts of rainfall are very important for decision making such as storm warnings or flood risk downstream watersheds. We present a statistical post-processing method based on an extension of Quantile Regression Forests (QRF) for heavy-tailed distributions. Our proposed method is applied to daily 51-h forecasts of 6-h accumulated precipitation from 2012 to 2015 over France using the Météo-France ensemble prediction system called PEARP. It provides calibrated predictive distributions and competes favourably with methods like Analog method or EMOS, which we try to improve using some new predictors and distributions derived from hydrology. We also discuss about evaluation of ensemble forecasts for extreme and rare events. Our goal is to improve drastically ensemble quality for these events subject to a good overall performance.

  10. CHANGES IN FREQUENCY, PERSISTENCE AND INTENSITY OF EXTREME HIGH-TEMPERATURE EVENTS IN THE ROMANIAN PLAIN

    Directory of Open Access Journals (Sweden)

    DRAGOTĂ CARMEN-SOFIA

    2015-03-01

    Full Text Available Recent summer heat waves (2003, 2010 had a strong socio-economic impact in different parts of the continent by means of crop shortfalls and forest fires. Sustained hot days became more frequent in the recent decades in many European regions, affecting human health and leading to additional deaths. This signal has been outlined in many studies conducted in Romania, suggesting that the southern region of Romania is particularly subject to large temperature increase. This work investigates the changing annual and seasonal heat waves at regional scale of the Romanian Plain, over period 1961-2014. Daily maximum temperature recorded at six weather stations available from the ECA&D project (European Climate Assessment and Datasets were analyzed. The changes in the seasonal frequency, duration and intensity of heat waves were studied using the Mann-Kendall nonparametric trend test, as recommended by the scientific expert team on climate change detection. The likelyhood of higher maximum temperatures rise, particularly after the mid 1980s, and the changes in the upper tail of the probability density functions of these temperatures, within the extreme domain (beyond the 95% percentile level, explain the persistence and intensity of heat waves. The upward trends are dominant most of the year, and many of the calculated decadal slopes were found statistically significant (relative to the 5% level, proving an ongoing and strong warming all over the region. Our findings are in good agreement with several recent studies carried out at European and national scale and pledge for further scientific analyses i.e. heat stress impact on public health and agriculture.

  11. Flood-risk mapping: contributions towards an enhanced assessment of extreme events and associated risks

    Directory of Open Access Journals (Sweden)

    B. Büchele

    2006-01-01

    Full Text Available Currently, a shift from classical flood protection as engineering task towards integrated flood risk management concepts can be observed. In this context, a more consequent consideration of extreme events which exceed the design event of flood protection structures and failure scenarios such as dike breaches have to be investigated. Therefore, this study aims to enhance existing methods for hazard and risk assessment for extreme events and is divided into three parts. In the first part, a regionalization approach for flood peak discharges was further developed and substantiated, especially regarding recurrence intervals of 200 to 10 000 years and a large number of small ungauged catchments. Model comparisons show that more confidence in such flood estimates for ungauged areas and very long recurrence intervals may be given as implied by statistical analysis alone. The hydraulic simulation in the second part is oriented towards hazard mapping and risk analyses covering the whole spectrum of relevant flood events. As the hydrodynamic simulation is directly coupled with a GIS, the results can be easily processed as local inundation depths for spatial risk analyses. For this, a new GIS-based software tool was developed, being presented in the third part, which enables estimations of the direct flood damage to single buildings or areas based on different established stage-damage functions. Furthermore, a new multifactorial approach for damage estimation is presented, aiming at the improvement of damage estimation on local scale by considering factors like building quality, contamination and precautionary measures. The methods and results from this study form the base for comprehensive risk analyses and flood management strategies.

  12. 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

  13. Extreme monsoon precipitation events over South Asia in a warming world

    Science.gov (United States)

    Raghavan, K.; Sabin, T. P.; Mujumdar, M.; Priya, P.

    2012-04-01

    The recent series of flood events over Pakistan and Northwest India during the monsoon seasons of 2010 and 2011 are examples of extreme phenomena during the last century that have evoked considerable interest among various scientific communities. One of the causes for the 2010 intense precipitation over Pakistan has been attributed to the interaction between the tropical monsoon surge and southward intruding extra-tropical circulation anomalies (Hong et al. 2011). On the other hand, it has been hypothesized by Mujumdar et al. (2012) that the westward shift of the West Pacific Subtropical High (WPSH) in response to the strong La Nina conditions during 2010 was instrumental in altering the convection and circulation over the Bay of Bengal and the monsoon trough region, which in turn sustained the moist convective activities over Indo-Pak through transport of moisture from the Arabian Sea. However several aspects of the dynamics of these intense monsoon precipitation events are not adequately understood especially when atmospheric convective instabilities are expected to amplify in the backdrop of the ongoing global warming. Here, we have carried out a set of ensemble simulation experiments using a high-resolution global climate model to understand the evolution of intense monsoon precipitation events over Pakistan and Northwest India as in 2010. The results based on the model simulations indicate that while interactions among the WPSH, the South Asian monsoon trough and sub-tropical westerlies are conducive for development of convective instabilities over the Indo-Pak region, the local convective activities are found to significantly amplify in response to the large build up of moisture associated with global warming. The present results have implications in understanding how extreme monsoon precipitation events in the Indo-Pak region might have responded to past climatic variations.

  14. 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

  15. 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

  16. Identification of Extreme Events Under Climate Change Conditions Over Europe and The Northwest-atlantic Region: Spatial Patterns and Time Series Characteristics

    Science.gov (United States)

    Leckebusch, G.; Ulbrich, U.; Speth, P.

    In the context of climate change and the resulting possible impacts on socio-economic conditions for human activities it seems that due to a changed occurrence of extreme events more severe consequences have to be expected than from changes in the mean climate. These extreme events like floods, excessive heats and droughts or windstorms possess impacts on human social and economic life in different categories such as forestry, agriculture, energy use, tourism and the reinsurance business. Reinsurances are affected by nearly 70% of all insured damages over Europe in the case of wind- storms. Especially the December 1999 French windstorms caused damages about 10 billion. A new EU-founded project (MICE = Modelling the Impact of Climate Ex- tremes) will focus on these impacts caused by changed occurrences of extreme events over Europe. Based upon the output of general circulation models as well as regional climate models, investigations are carried out with regard to time series characteristics as well as the spatial patterns of extremes under climate changed conditions. After the definition of specific thresholds for climate extremes, in this talk we will focus on the results of the analysis for the different data sets (HadCM3 and CGCMII GCM's and RCM's, re-analyses, observations) with regard to windstorm events. At first the results of model outputs are validated against re-analyses and observations. Especially a comparison of the stormtrack (2.5 to 8 day bandpass filtered 500 hPa geopotential height), cyclone track, cyclone frequency and intensity is presented. Highly relevant to damages is the extreme wind near the ground level, so the 10 m wind speed will be investigated additionally. of special interest to possible impacts is the changed spatial occurrence of windspeed maxima under 2xCO2-induced climate change.

  17. Heat wave beats green wave: the effect of a climate extreme on alpine grassland phenology as seen by phenocams

    Science.gov (United States)

    Cremonese, Edoardo; Filippa, Gianluca; Migliavacca, Mirco; Siniscalco, Consolata; Oddi, Ludovica; Galvagno, Marta

    2016-04-01

    The year 2015 has been one of the warmest on record for many regions of the world. The record-breaking temperatures did not spare the European Alps, where the summer anomaly reached +4°C. This heat wave caused important impacts on the seasonal development and structural properties of alpine grasslands that deserve investigations. Phenocams are useful tools to describe canopy greenness seasonal dynamics and many recent studies demonstrated that the major phenological events (e.g. budbrust, senescence, …) can be extracted from greenness trajectories. In contrast, little is know about their capabilities to describe the impact of extreme climate events on a fully developed canopy. Moreover the relation between quantitative structural and functional vegetation properties (e.g. biomass, LAI, …) and phenocam data remains poorly investigated. In this study we examine the impact of the 2015 summer heat wave on a subalpine grassland by jointly analyzing phenocam greenness trajectories, proximal sensing and flux data together with field measures of vegetation structural properties. The effect of different environmental drivers on greenness seasonal development was further evaluated by a modeling approach (GSI model). Phenocam tracked the impact of heatwave 2015 that caused a lower canopy development and an anticipation of yellowing by more than 2 months. The same pattern was observed for CO2 fluxes, NDVI and field measures. GSI model results show that during the heatwave, a combination of moisture and high temperature limitation was responsible for the observed reduction of the canopy development. Moreover, spatially explicit analysis of digital images allowed to highlight the differential response of specific plant functional types to the extreme event.

  18. Application of radar data to estimate distributed return periods of extreme rainfall events over Trondheim

    Energy Technology Data Exchange (ETDEWEB)

    Abdella, Yisak Sultan

    2013-07-01

    The return period of a given rainfall intensity is an important parameter for the Trondheim municipality since the drainage systems in Trondheim have been and are still being designed on the basis of a selected return period. Since rainfall is a spatially distributed phenomenon, a single event passing over a city can yield different return periods at different locations in the same city. In order to account for this spatial variability, a tool has been developed in this project for determining distributed return periods for rainfall events over Trondheim using the measurements from Rissa radar. The tool includes a method for adjusting radar rainfall using rain gauge measurements and an accumulation technique which accounts for storm movement and temporal variation in intensity. The tool has been tested on two extreme events which occurred on July 29 2007 and August 13 2007. The application on the two events has demonstrated a fully-automated estimation of distributed return periods using readily available data. For the particular rain gauge network in Trondheim, it has also been shown how areas of maximum intensity observed by the radar can be missed by all the gauges. (author)

  19. Impacts of the November 2014 extreme rainfall event in Ticino, Switzerland

    Science.gov (United States)

    Voumard, Jérémie; Matasci, Battista; Derron, Marc-Henri; Jaboyedoff, Michel

    2015-04-01

    the canton of Ticino with over 15'500 citizen, the shores along the Lake Maggiore were flooded until 300 meters inside the land. Dozens of basements and ground floor of buildings were flooded. Hillslopes were strongly affected by landslides, while floods occurred in valley bottoms. The aim of this study is to document the natural events and their consequences in terms of transportation networks and societal inconveniences caused by this rainfall event. Damages and consequences of the events were documented during a field visit, obtained from the media and the official reports as well as by the aid of a drone in two areas. We suspected that many impacted houses were located in areas where landslides could be expected. A first assessment based on geomorphological landscape analysis with an Airborne Lidar DEM show that some of these infrastructures seem to be built on alluvial / debris cones, suspected ancient landslides or steep slopes susceptible to be affected by (shallow) landslides, debris flows or rockfalls during extreme meteorological events. This raises the delicate question of urbanization in steep mountain slopes even if since a several tens of years nothing happened. More detailed studies about those hypotheses are necessary to understand the relationship between suspected old slope movements and the shallow landslides occurred during the November 2014 extreme rainfall event. The transportation network in the canton of Ticino is vulnerable to extreme natural events because of a high number of artificially cut and fill slopes along the lanes. In some cases, a possibility to investigate could be to reduce the number of roads leading to a same place in order to concentrate enough financial, logistic and maintenance strengths on only one access well protected against natural hazards.

  20. 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.

  1. Enhanced greenhouse gas emission from exposed sediments along a hydroelectric reservoir during an extreme drought event

    Science.gov (United States)

    Jin, Hyojin; Yoon, Tae Kyung; Lee, Seung-Hoon; Kang, Hojeong; Im, Jungho; Park, Ji-Hyung

    2016-12-01

    An active debate has been underway on the magnitude and duration of carbon (C) emissions from hydroelectric reservoirs, yet little attention has been paid to stochastic C emissions from reservoir sediments during extreme climatic events. A rare opportunity for field measurements of CO2 efflux from a hydroelectric reservoir in Korea during an extreme drought event was used to examine how prolonged droughts can affect microbial organic matter processing and the release of CO2, CH4 and N2O from exposed sediments. Chamber measurements of CO2 efflux along an exposed sediment transect, combined with high-frequency continuous sensor measurements of the partial pressure of CO2 (pCO2) in the reservoir surface water, exhibited extraordinary pulses of CO2 from exposed sediments and the turbulent inflowing water in contrast to a small CO2 sink in the main water body of the reservoir and a low efflux of CO2 from the flooded sediment. Significant increases in the production of CO2, CH4 and N2O observed in a laboratory incubation of sediments, together with enhanced activities of phenol oxidase and three hydrolases, indicate a temporary activation of microbial organic matter processing in the drying sediment. The results suggest that drought-triggered pulses of greenhouse gas emission from exposed sediments can offset the C accumulation in reservoir sediments over time scales of years to decades, reversing the trend of declining C emissions from aging reservoirs.

  2. Application of Data Cubes for Improving Detection of Water Cycle Extreme Events

    Science.gov (United States)

    Albayrak, Arif; Teng, William

    2015-01-01

    As part of an ongoing NASA-funded project to remove a longstanding barrier to accessing NASA data (i.e., accessing archived time-step array data as point-time series), for the hydrology and other point-time series-oriented communities, "data cubes" are created from which time series files (aka "data rods") are generated on-the-fly and made available as Web services from the Goddard Earth Sciences Data and Information Services Center (GES DISC). Data cubes are data as archived rearranged into spatio-temporal matrices, which allow for easy access to the data, both spatially and temporally. A data cube is a specific case of the general optimal strategy of reorganizing data to match the desired means of access. The gain from such reorganization is greater the larger the data set. As a use case of our project, we are leveraging existing software to explore the application of the data cubes concept to machine learning, for the purpose of detecting water cycle extreme events, a specific case of anomaly detection, requiring time series data. We investigate the use of support vector machines (SVM) for anomaly classification. We show an example of detection of water cycle extreme events, using data from the Tropical Rainfall Measuring Mission (TRMM).

  3. Integrated safety assessment of Indian nuclear power plants for extreme events: Reducing impact on public mind

    Indian Academy of Sciences (India)

    Anil Kakodkar; Ram Kumar Singh

    2013-10-01

    Nuclear energy professionals need to understand and address the catastrophe syndrome that of late seems to be increasingly at work in public mind in the context of nuclear energy. Classically the nuclear power reactor design and system evolution has been based on the logic of minimization of risk to an acceptable level and its quantification based on a deterministic approach and backed up by a further assessment based on the probabilistic methodology. However, in spite of minimization of risk, the reasons for anxiety and trauma in public mind that still prevails in the context of severe accidents needs to be understood and addressed. Margins between maximum credible accidents factored in the design and the ultimate load withstanding capacities of relevant systems need to be enhanced and guaranteed with a view to minimize release of radioactivity and avoid serious impact in public domain. A more realistic basis for management of an accident in public domain also needs to be quantified for this purpose. Assurance to public on limiting the consequences to a level that does not lead to a trauma is something that we need to be able to credibly demonstrate and confirm. The findings from Chernobyl reports point to significant psychological effects and related health disorders due to large scale emergency relocation of people that could have been possibly reduced by an order of magnitude without significant additional safety detriment. A combination of probabilistic and deterministic approaches should be evolved further to minimize consequences in public domain through enhancing safety margins and adding greater precision to quantitatively predicting accident progression and its management. The paper presents the case studies of the extreme external event such as tsunami and its impact on the coastal nuclear plants in India, the containment integrity assessment under the extreme internal event of over-pressurization and aircraft impact along with hydrogen deflagration

  4. 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.

  5. The use of geoinformatic data and spatial analysis to predict faecal pollution during extreme precipitation events

    Science.gov (United States)

    Ward, Ray; Purnell, Sarah; Ebdon, James; Nnane, Daniel; Taylor, Huw

    2013-04-01

    The Water Framework Directive (WFD) regulates surface water quality standards in the European Union (EU). The Directive call for the identification and management of point and diffuse sources of pollution and requires the establishment of a 'programme of measures' for identified river basin districts, in order to achieve a "good status" by 2015. The hygienic quality of water is normally monitored using faecal indicator organisms (FIO), such as Escherichia coli, which indicate a potential risk to public health from human waterborne pathogens. Environmental factors influence the transmission of these pathogens and indicator organisms, and statistically significant relationships have been found between rainfall and outbreaks of waterborne disease. Climate change has been predicted to lead to an increase in severe weather events in many parts of Europe, including an increase in the frequency of extreme rainfall events. This in turn is likely to lead to an increase in incidents of human waterborne disease in Europe, unless measures are taken to predict and mitigate for such events. This study investigates a variety of environmental factors that influence the concentration of FIO in surface waters receiving faecal contamination from a variety of sources. Levels of FIO, including Escherichia coli, intestinal enterococci, somatic coliphage and GB124 (a human-specific microbial source tracking marker), were monitored in the Sussex Ouse catchment in Southeast England over a period of 26 months. These data were combined with geoinformatic environmental data within a GIS to map faecal contamination within the river. Previously, precipitation and soil erosion have been identified as major factors that can influence the concentration of these faecal markers, and studies have shown that slope, soil type and vegetation influence both the mechanisms and the rate by which erosion occurs in river catchments. Of the environmental variables studied, extreme precipitation was found to

  6. Monitoring Changes of Tropical Extreme Rainfall Events Using Differential Absorption Barometric Radar (DiBAR)

    Science.gov (United States)

    Lin, Bing; Harrah, Steven; Lawrence, R. Wes; Hu, Yongxiang; Min, Qilong

    2015-01-01

    This work studies the potential of monitoring changes in tropical extreme rainfall events such as tropical storms from space using a Differential-absorption BArometric Radar (DiBAR) operating at 50-55 gigahertz O2 absorption band to remotely measure sea surface air pressure. Air pressure is among the most important variables that affect atmospheric dynamics, and currently can only be measured by limited in-situ observations over oceans. Analyses show that with the proposed radar the errors in instantaneous (averaged) pressure estimates can be as low as approximately 5 millibars (approximately 1 millibar) under all weather conditions. With these sea level pressure measurements, the forecasts, analyses and understanding of these extreme events in both short and long time scales can be improved. Severe weathers, especially hurricanes, are listed as one of core areas that need improved observations and predictions in WCRP (World Climate Research Program) and NASA Decadal Survey (DS) and have major impacts on public safety and national security through disaster mitigation. Since the development of the DiBAR concept about a decade ago, our team has made substantial progress in advancing the concept. Our feasibility assessment clearly shows the potential of sea surface barometry using existing radar technologies. We have developed a DiBAR system design, fabricated a Prototype-DiBAR (P-DiBAR) for proof-of-concept, conducted lab, ground and airborne P-DiBAR tests. The flight test results are consistent with our instrumentation goals. Observational system simulation experiments for space DiBAR performance show substantial improvements in tropical storm predictions, not only for the hurricane track and position but also for the hurricane intensity. DiBAR measurements will lead us to an unprecedented level of the prediction and knowledge on tropical extreme rainfall weather and climate conditions.

  7. Statistical similarities of pre-earthquake electromagnetic emissions to biological and economic extreme events

    Science.gov (United States)

    Potirakis, Stelios M.; Contoyiannis, Yiannis; Kopanas, John; Kalimeris, Anastasios; Antonopoulos, George; Peratzakis, Athanasios; Eftaxias, Konstantinos; Nomicos, Costantinos

    2014-05-01

    When one considers a phenomenon that is "complex" refers to a system whose phenomenological laws that describe the global behavior of the system, are not necessarily directly related to the "microscopic" laws that regulate the evolution of its elementary parts. The field of study of complex systems considers that the dynamics of complex systems are founded on universal principles that may be used to describe disparate problems ranging from particle physics to economies of societies. Several authors have suggested that earthquake (EQ) dynamics can be analyzed within similar mathematical frameworks with economy dynamics, and neurodynamics. A central property of the EQ preparation process is the occurrence of coherent large-scale collective behavior with a very rich structure, resulting from repeated nonlinear interactions among the constituents of the system. As a result, nonextensive statistics is an appropriate, physically meaningful, tool for the study of EQ dynamics. Since the fracture induced electromagnetic (EM) precursors are observable manifestations of the underlying EQ preparation process, the analysis of a fracture induced EM precursor observed prior to the occurrence of a large EQ can also be conducted within the nonextensive statistics framework. Within the frame of the investigation for universal principles that may hold for different dynamical systems that are related to the genesis of extreme events, we present here statistical similarities of the pre-earthquake EM emissions related to an EQ, with the pre-ictal electrical brain activity related to an epileptic seizure, and with the pre-crisis economic observables related to the collapse of a share. It is demonstrated the all three dynamical systems' observables can be analyzed in the frame of nonextensive statistical mechanics, while the frequency-size relations of appropriately defined "events" that precede the extreme event related to each one of these different systems present striking quantitative

  8. Characteristics of storms that contribute to extreme precipitation events over the Iberian Peninsula

    Science.gov (United States)

    Trigo, Ricardo; Ramos, Alexandre M.; Ordoñez, Paulina; Liberato, Margarida L. R.; Trigo, Isabel F.

    2014-05-01

    Floods correspond to one of the most deadly natural disasters in the Iberian Peninsula during the last century. Quite often these floods are associated to intense low pressure systems with an Atlantic origin. In recent years a number of episodes have been evaluated on a case-by-case approach, with a clear focus on extreme events, thus lacking a systematic assessment. In this study we focus on the characteristics of storms for the extended winter season (October to March) that are responsible for the most extreme rainfall events over large areas of the Iberian Peninsula. An objective method for ranking daily precipitation events during the extended winter is used based on the most comprehensive database of high resolution (0.2º latitude by 0.2º longitude) gridded daily precipitation dataset available for the Iberian Peninsula. The magnitude of an event is obtained after considering the total area affected as well as its intensity in every grid point (taking into account the daily normalised departure from climatology). Different precipitation rankings are studied considering the entire Iberian Peninsula, Portugal and also the six largest river basins in the Iberian Peninsula (Duero, Ebro, Tagus, Minho, Guadiana and Guadalquivir). Using an objective cyclone detecting and tracking scheme [Trigo, 2006] the storm track and characteristics of the cyclones were obtained using the ERA-Interim reanalyses for the 1979-2008 period. The spatial distribution of extratropical cyclone positions when the precipitation extremes occur will be analysed over the considered sub-domains (Iberia, Portugal, major river basins). In addition, we distinguish the different cyclone characteristics (lifetime, direction, minimum pressure, position, velocity, vorticity and radius) with significant impacts in precipitation over the different domains in the Iberian Peninsula. This work was partially supported by FEDER (Fundo Europeu de Desenvolvimento Regional) funds through the COMPETE (Programa

  9. Reconstructing extreme AMOC events through nudging of the ocean surface: a perfect model approach

    Science.gov (United States)

    Ortega, Pablo; Guilyardi, Eric; Swingedouw, Didier; Mignot, Juliette; Nguyen, Sébastien

    2017-01-01

    While the Atlantic Meridional Overturning Circulation (AMOC) is thought to be a crucial component of the North Atlantic climate, past changes in its strength are challenging to quantify, and only limited information is available. In this study, we use a perfect model approach with the IPSL-CM5A-LR model to assess the performance of several surface nudging techniques in reconstructing the variability of the AMOC. Special attention is given to the reproducibility of an extreme positive AMOC peak from a preindustrial control simulation. Nudging includes standard relaxation techniques towards the sea surface temperature and salinity anomalies of this target control simulation, and/or the prescription of the wind-stress fields. Surface nudging approaches using standard fixed restoring terms succeed in reproducing most of the target AMOC variability, including the timing of the extreme event, but systematically underestimate its amplitude. A detailed analysis of the AMOC variability mechanisms reveals that the underestimation of the extreme AMOC maximum comes from a deficit in the formation of the dense water masses in the main convection region, located south of Iceland in the model. This issue is largely corrected after introducing a novel surface nudging approach, which uses a varying restoring coefficient that is proportional to the simulated mixed layer depth, which, in essence, keeps the restoring time scale constant. This new technique substantially improves water mass transformation in the regions of convection, and in particular, the formation of the densest waters, which are key for the representation of the AMOC extreme. It is therefore a promising strategy that may help to better constrain the AMOC variability and other ocean features in the models. As this restoring technique only uses surface data, for which better and longer observations are available, it opens up opportunities for improved reconstructions of the AMOC over the last few decades.

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

    Science.gov (United States)

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

    2001-05-01

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

  11. 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

  12. Manaus city Flow Warning system and extreme events monitoring in the Amazon Basin

    Science.gov (United States)

    Santos, A. L. M. R.; Oliveira, D.; Oliveira, M. A.; Moreira, D.; Maciel, J. S. C.

    2012-04-01

    The Amazon basin is the biggest watershed in the world, in the center of this basin, there is a city called Manaus, with population next to 2 million habitants. Manaus city is bounded by Negro River; one of the main rivers in Amazon, this river has its level checked by Fluvial Station in the Manaus harbor, which has a range of 100 years of hydrological data records. The hydrological cycle in the region next to Manaus has certain regularity, its common variety is considered of 7 months of rising river, in other words, the fluvial quotes rising and 5 months of falling (ebb). Although, the water level variation in Manaus Harbor, from its draft to flow can achieve the variation up to 16 meters of water level height, this difference can affect all the Amazon region, happening impacts such as the interference of regional agriculture and fluvial transportation, besides the economic activities in the harbor and local population welfare, arising from extreme events. Considering the relevance of prediction and accompanying of flows and drafts, the Geologic Survey of Brazil implemented, since 1989, a warning system to these extreme events. This paper focused to demonstrate the a warning system implemented from equations based on the Manaus Harbor quotes, since Negro River has a regular hydrological cycle, thus, it is possible to predict the highest quotes in the hydrological year, in advance till 75 days with accurate prediction, in a gap of 45 to 15 days before the flow. This paper presents, also, the biggest events occurred in a hundred years of records collected by Manaus Harbor, as example, the draft happened in December 2010 and the flow in June 2009, as well demonstrating the values and impacts in the Amazon region.

  13. Jellyfish: the origin and distribution of extreme ram-pressure stripping events in massive galaxy clusters

    Science.gov (United States)

    McPartland, Conor; Ebeling, Harald; Roediger, Elke; Blumenthal, Kelly

    2016-01-01

    We investigate the observational signatures and physical origin of ram-pressure stripping (RPS) in 63 massive galaxy clusters at z = 0.3-0.7, based on images obtained with the Hubble Space Telescope. Using a training set of a dozen `jellyfish' galaxies identified earlier in the same imaging data, we define morphological criteria to select 211 additional, less obvious cases of RPS. Spectroscopic follow-up observations of 124 candidates so far confirmed 53 as cluster members. For the brightest and most favourably aligned systems, we visually derive estimates of the projected direction of motion based on the orientation of apparent compression shocks and debris trails. Our findings suggest that the onset of these events occurs primarily at large distances from the cluster core (>400 kpc), and that the trajectories of the affected galaxies feature high-impact parameters. Simple models show that such trajectories are highly improbable for galaxy infall along filaments but common for infall at high velocities, even after observational biases are accounted for, provided the duration of the resulting RPS events is ≲500 Myr. We thus tentatively conclude that extreme RPS events are preferentially triggered by cluster mergers, an interpretation that is supported by the disturbed dynamical state of many of the host clusters. This hypothesis implies that extreme RPS might occur also near the cores of merging poor clusters or even merging groups of galaxies. Finally, we present nine additional `jellyfish" galaxies at z > 0.3 discovered by us, thereby doubling the number of such systems known at intermediate redshift.

  14. Development of an Evaluation Methodology for Loss of Large Area induced from extreme events

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sok Chul; Park, Jong Seuk; Kim, Byung Soon; Jang, Dong Ju; Lee, Seung Woo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    USNRC announced several regulatory requirements and guidance documents regarding the event of loss of large area including 10CFR 50.54(hh), Regulatory Guide 1.214 and SRP 19.4. In Korea, consideration of loss of large area has been limitedly taken into account for newly constructing NPPs as voluntary based. In general, it is hardly possible to find available information on methodology and key assumptions for the assessment of LOLA due to 'need to know based approach'. Urgent needs exists for developing country specific regulatory requirements, guidance and evaluation methodology by themselves with the consideration of their own geographical and nuclear safety and security environments. Currently, Korea Hydro and Nuclear Power Company (KHNP) has developed an Extended Damage Mitigation Guideline (EDMG) for APR1400 under contract with foreign consulting company. The submittal guidance NEI 06-12 related to B.5.b Phase 2 and 3 focused on unit-wise mitigation strategy instead of site level mitigation or response strategy. Phase 1 mitigating strategy and guideline for LOLA (Loss of Large Area) provides emphasis on site level arrangement including cooperative networking outside organizations and agile command and control system. Korea Institute of Nuclear Safety has carried out a pilot in-house research project to develop the methodology and guideline for evaluation of LOLA since 2014. This paper introduces the summary of major results and outcomes of the aforementioned research project. After Fukushima Dai-Ichi accident, the awareness on countering the event of loss of large area induced from extreme man-made hazards or extreme beyond design basis external event. Urgent need exists to develop regulatory guidance for coping with this undesirable situation, which has been out of consideration at existing nuclear safety regulatory framework due to the expectation of rare possibility of occurrence.

  15. Assessment of extreme quantitative precipitation forecasts and development of regional extreme event thresholds using data from HMT-2006 and COOP observers

    Science.gov (United States)

    Ralph, F.M.; Sukovich, E.; Reynolds, D.; Dettinger, M.; Weagle, S.; Clark, W.; Neiman, P.J.

    2010-01-01

    Extreme precipitation events, and the quantitative precipitation forecasts (QPFs) associated with them, are examined. The study uses data from the Hydrometeorology Testbed (HMT), which conducted its first field study in California during the 2005/06 cool season. National Weather Service River Forecast Center (NWS RFC) gridded QPFs for 24-h periods at 24-h (day 1), 48-h (day 2), and 72-h (day 3) forecast lead times plus 24-h quantitative precipitation estimates (QPEs) fromsites in California (CA) and Oregon-Washington (OR-WA) are used. During the 172-day period studied, some sites received more than 254 cm (100 in.) of precipitation. The winter season produced many extreme precipitation events, including 90 instances when a site received more than 7.6 cm (3.0 in.) of precipitation in 24 h (i.e., an "event") and 17 events that exceeded 12.7 cm (24 h)-1 [5.0 in. (24 h)-1]. For the 90 extreme events f.7.6 cm (24 h)-1 [3.0 in. (24 h)-1]g, almost 90% of all the 270 QPFs (days 1-3) were biased low, increasingly so with greater lead time. Of the 17 observed events exceeding 12.7 cm (24 h)-1 [5.0 in. (24 h)-1], only 1 of those events was predicted to be that extreme. Almost all of the extreme events correlated with the presence of atmospheric river conditions. Total seasonal QPF biases for all events fi.e., $0.025 cm (24 h)-1 [0.01 in. (24 h)-1]g were sensitive to local geography and were generally biased low in the California-Nevada River Forecast Center (CNRFC) region and high in the Northwest River Forecast Center(NWRFC) domain. The low bias in CA QPFs improved with shorter forecast lead time and worsened for extreme events. Differences were also noted between the CNRFC and NWRFC in terms of QPF and the frequency of extreme events. A key finding from this study is that there were more precipitation events .7.6 cm (24 h)-1 [3.0 in. (24 h)21] in CA than in OR-WA. Examination of 422 Cooperative Observer Program (COOP) sites in the NWRFC domain and 400 in the CNRFC domain

  16. A long record of extreme wave events in coastal Lake Hamana, Japan

    Science.gov (United States)

    Boes, Evelien; Yokoyama, Yusuke; Schmidt, Sabine; Riedesel, Svenja; Fujiwara, Osamu; Nakamura, Atsunori; Garrett, Ed; Heyvaert, Vanessa; Brückner, Helmut; De Batist, Marc

    2017-04-01

    Coastal Lake Hamana is located near the convergent tectonic boundary of the Nankai-Suruga Trough, along which the Philippine Sea slab is subducted underneath the Eurasian Plate, giving rise to repeated tsunamigenic megathrust earthquakes (Mw ≥ 8). A good understanding of the earthquake- and tsunami-triggering mechanisms is crucial in order to better estimate the complexity of seismic risks. Thanks to its accommodation space, Lake Hamana may represent a good archive for past events, such as tsunamis and tropical storms (typhoons), also referred to as "extreme wave" events. Characteristic event layers, consisting of sediment entrained by these extreme waves and their backwash, are witnesses of past marine incursions. By applying a broad range of surveying methods (reflection-seismic profiling, gravity coring, piston coring), sedimentological analyses (CT-scanning, XRF-scanning, multi-sensor core logging, grain size, microfossils etc.) and dating techniques (210Pb/137Cs, 14C, OSL, tephrochronology), we attempt to trace extreme wave event deposits in a multiproxy approach. Seismic imagery shows a vertical stacking of stronger reflectors, interpreted to be coarser-grained sheets deposited by highly energetic waves. Systematic sampling of lake bottom sediments along a transect from ocean-proximal to ocean-distal sites enables us to evaluate vertical and lateral changes in stratigraphy. Ocean-proximal, we observe a sequence of eight sandy units separated by silty background sediments, up to a depth of 8 m into the lake bottom. These sand layers quickly thin out and become finer-grained land-inward. Seismic-to-core correlations show a good fit between the occurrence of strong reflectors and sandy deposits, hence confirming presumptions based on acoustic imagery alone. Sand-rich intervals typically display a higher magnetic susceptibility, density and stronger X-ray attenuation. However, based on textural and structural differences, we can make the distinction between

  17. The CAULDRON game: Helping decision makers understand extreme weather event attribution

    Science.gov (United States)

    Walton, P.; Otto, F. E. L.

    2014-12-01

    There is a recognition from academics and stakeholders that climate science has a fundamental role to play in the decision making process, but too frequently there is still uncertainty about what, when, how and why to use it. Stakeholders suggest that it is because the science is presented in an inaccessible manner, while academics suggest it is because the stakeholders do not have the scientific knowledge to understand and apply the science appropriately. What is apparent is that stakeholders need support, and that there is an onus on academia to provide it. This support is even more important with recent developments in climate science, such as extreme weather event attribution. We are already seeing the impacts of extreme weather events around the world causing lost of life and damage to property and infrastructure with current research suggesting that these events could become more frequent and more intense. If this is to be the case then a better understanding of the science will be vital in developing robust adaptation and business planning. The use of games, role playing and simulations to aid learning has long been understood in education but less so as a tool to support stakeholder understanding of climate science. Providing a 'safe' space where participants can actively engage with concepts, ideas and often emotions, can lead to deep understanding that is not possible through more passive mechanisms such as papers and web sites. This paper reports on a game that was developed through a collaboration led by the Red Cross/Red Crescent, University of Oxford and University of Reading to help stakeholders understand the role of weather event attribution in the decision making process. The game has already been played successfully at a number of high profile events including COP 19 and the African Climate Conference. It has also been used with students as part of a postgraduate environmental management course. As well as describing the design principles of the

  18. Effect of Enhanced Air Temperature (extreme heat, and Load of Non-Linear Against the Use of Electric Power

    Directory of Open Access Journals (Sweden)

    I Ketut Wijaya

    2015-12-01

    Full Text Available Usage Electric power is very easy to do, because the infrastructure for connecting  already available and widely sold. Consumption electric power is not accompanied by the ability to recognize electric power. The average increase of electricity power in Bali in extreme weather reaches 10% in years 2014, so that Bali suffered power shortages and PLN as the manager of electric power to perform scheduling on of electric power usage. Scheduling is done because many people use electric power as the load  of fan and Air Conditioner exceeding the previous time. Load of fan, air conditioning, and computers including non-linear loads which can add heat on the conductor of electricity. Non-linear load and hot weather can lead to heat on conductor so  insulation damaged  and cause electrical short circuit. Data of electric power obtained through questionnaires, surveys, measurement and retrieve data from various parties. Fires that occurred in 2014, namely 109 events, 44 is  event caused by an electric short circuit (approximately 40%. Decrease power factors can cause losses of electricity and hot. Heat can cause and adds heat on the  conductor electric. The analysis showed  understanding electric power of the average  is 27,700 with value between 20 to 40. So an understanding of the electrical power away from the understand so that many errors because of the act own. Installation tool ELCB very necessary but very necessary provide counseling   of electricity to the community.

  19. Digital Learning Network Education Events of NASA's Extreme Environments Mission Operations

    Science.gov (United States)

    Paul, Heather; Guillory, Erika

    2007-01-01

    NASA's Digital Learning Network (DLN) reaches out to thousands of students each year through video conferencing and web casting. The DLN has created a series of live education videoconferences connecting NASA s Extreme Environment Missions Operations (NEEMO) team to students across the United States. The programs are also extended to students around the world live web casting. The primary focus of the events is the vision for space exploration. During the programs, NEEMO Crewmembers including NASA astronauts, engineers and scientists inform and inspire students about the importance of exploration and share the impact of the project as it correlates with plans to return to the moon and explore the planet Mars. These events highlight interactivity. Students talk live with the aquanauts in Aquarius, the National Oceanic and Atmospheric Administration s underwater laboratory. With this program, NASA continues the Agency s tradition of investing in the nation's education programs. It is directly tied to the Agency's major education goal of attracting and retaining students in science, technology, and engineering disciplines. Before connecting with the aquanauts, the students conduct experiments of their own designed to coincide with mission objectives. This paper describes the events that took place in September 2006.

  20. 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

  1. Widespread extreme drought events in Iberia and their relationship with North Atlantic moisture flux deficit

    Science.gov (United States)

    Liberato, Margarida L. R.; Montero, Irene; Russo, Ana; Gouveia, Célia; Ramos, Alexandre M.; Trigo, Ricardo M.

    2015-04-01

    Droughts represent one of the most frequent climatic extreme events on the Iberian Peninsula, often with widespread negative ecological and environmental impacts, resulting in major socio-economic damages such as large decreases in hydroelectricity and agricultural productions or increasing forest fire risk. Unlike other weather driven extreme events, droughts duration could be from few months to several years. Here we employ a recently developed climatic drought index, the Standardized Precipitation Evapotranspiration Index (SPEI; Vicente-Serrano et al. 2010a), based on the simultaneous use of precipitation and temperature fields. This index holds the advantage of combining a multi-scalar character with the capacity to include the effects of temperature variability on drought assessment (Vicente-Serrano et al., 2010a). In this study the SPEI was computed using the Climatic Research Unit (CRU) TS3.21 High Resolution Gridded Data (0.5°) for the period 1901-2012. At this resolution the study region of Iberian Peninsula corresponds to a square of 30x30 grid pixels. The CRU Potential Evapotranspiration (PET) was used, through the Penmann-Monteith equation and the log-logistic probability distribution. This formulation allows a very good fit to the series of differences between precipitation and PET (Vicente-Serrano et al., 2010b), using monthly averages of daily maximum and minimum temperature data and also monthly precipitation records. The parameters were estimated by means of the L-moment method. The application of multi-scalar indices to the high-resolution datasets allows identifying whether the Iberian Peninsula is in hydric stress and also whether drought is installed. Based on the gridded SPEI datasets, spanning from 1901 to 2012, obtained for timescales 6, 12, 18 and 24 months, an objective method is applied for ranking the most extensive extreme drought events that occurred on the Iberian Peninsula. This objective method is based on the evaluation of the

  2. Helium, heat, and the generation of hydrothermal event plumes at mid-ocean ridges

    Science.gov (United States)

    Lupton, John E.; Baker, Edward T.; Massoth, Gary J.

    1999-09-01

    Hydrothermal event plumes are unique water-column features observed over mid-ocean ridges, presumably generated by the sudden release of large volumes of hot, buoyant fluid. Although the specifics of event plume generation are unknown, event plumes have been attributed to the rapid emptying of a hydrothermal reservoir or to rapid heat extraction from a recently emplaced dike or seafloor lava flows. The chemical and thermal signatures of event plumes as compared to the underlying steady-state plumes offer important clues to the generation of event plumes. Event plumes have low 3He/heat ratios of ˜0.4 × 10-17 mol J-1, similar to vent fluids from mature hydrothermal systems. In contrast, the steady-state plumes found beneath the event plumes have elevated and variable 3He/heat ratios of 2 to 5 × 10-17 mol J-1. Fluids collected directly over fresh lava flows have even higher 3He/heat ratios of 2 to 8 × 10-17 mol J-1, up to 30 times the event plume values. These disparate 3He/heat ratios place strong constraints on models of event plume generation, especially models which rely on heat extraction from seafloor eruptions. Published by Elsevier Science B.V.

  3. Characterizing the Impact of Extreme Heat on Mortality, Karachi, Pakistan, June 2015.

    Science.gov (United States)

    Ghumman, Usman; Horney, Jennifer

    2016-06-01

    Introduction Karachi, Pakistan was affected by a heat wave in June 2015 during the Muslim holy month of Ramadan. Many media reports attributed the excess deaths in part to the practice of daylight fasting during Ramadan. As much of the published research reports on heat-related mortality in Europe and the United States, an exploration of the effects of extreme heat on residents of a South Asian mega-city address a gap in current disaster research. Hypothesis/Problem This report investigated potential risk factors for excess mortality associated with the June 2015 heat wave in Karachi, Pakistan. Data were obtained through manual review of death certificates at public hospitals and private clinics in Karachi, Pakistan, conducted from July 1 through July 31, 2015 by a trained physician. Demographic data for any deaths with a primary cause of death of heat-related illness were recorded in Microsoft Excel (Microsoft Corp.; Redmond, Washington USA). EpiSheet (2012; Rothman. Modern Epidemiology. Lippincott Williams & Wilkins; Philadelphia, Pennsylvania USA) was used to calculate risk differences (RD), rate ratios (RR), and 95% confidence intervals (95% CI). Overall, residents of Karachi were approximately 17 times as likely to die of a heat-related cause of death during June 2015 (RR=17.68; 95% CI, 13.87-22.53) when compared with the reference period of June 2014. Residents with a monthly income lower than 20,000 Pakistani Rupees (US $196; RD=0.03; 95% CI, 0.01-0.05) and those with less than a fifth grade education (RD=0.03; 95% CI, 0.00-0.05) were at significantly higher risk of death during the 2015 heat wave compared to the reference period. Fasting during Ramadan was not a significant risk factor for mortality from heat-related causes during the Karachi heat wave of June 2015. A large number of excess deaths were reported across all demographic groups, which due to the burden of record keeping in an under-resourced health system during a public health emergency, are

  4. Ecological implications of extreme events: footprints of the 2010 earthquake along the Chilean coast.

    Directory of Open Access Journals (Sweden)

    Eduardo Jaramillo

    Full Text Available Deciphering ecological effects of major catastrophic events such as earthquakes, tsunamis, volcanic eruptions, storms and fires, requires rapid interdisciplinary efforts often hampered by a lack of pre-event data. Using results of intertidal surveys conducted shortly before and immediately after Chile's 2010 M(w 8.8 earthquake along the entire rupture zone (ca. 34-38°S, we provide the first quantification of earthquake and tsunami effects on sandy beach ecosystems. Our study incorporated anthropogenic coastal development as a key design factor. Ecological responses of beach ecosystems were strongly affected by the magnitude of land-level change. Subsidence along the northern rupture segment combined with tsunami-associated disturbance and drowned beaches. In contrast, along the co-seismically uplifted southern rupture, beaches widened and flattened increasing habitat availability. Post-event changes in abundance and distribution of mobile intertidal invertebrates were not uniform, varying with land-level change, tsunami height and coastal development. On beaches where subsidence occurred, intertidal zones and their associated species disappeared. On some beaches, uplift of rocky sub-tidal substrate eliminated low intertidal sand beach habitat for ecologically important species. On others, unexpected interactions of uplift with man-made coastal armouring included restoration of upper and mid-intertidal habitat seaward of armouring followed by rapid colonization of mobile crustaceans typical of these zones formerly excluded by constraints imposed by the armouring structures. Responses of coastal ecosystems to major earthquakes appear to vary strongly with land-level change, the mobility of the biota and shore type. Our results show that interactions of extreme events with human-altered shorelines can produce surprising ecological outcomes, and suggest these complex responses to landscape alteration can leave lasting footprints in coastal

  5. A twenty-first century California observing network for monitoring extreme weather events

    Science.gov (United States)

    White, A.B.; Anderson, M.L.; Dettinger, M.D.; Ralph, F.M.; Hinojosa, A.; Cayan, D.R.; Hartman, R.K.; Reynolds, D.W.; Johnson, L.E.; Schneider, T.L.; Cifelli, R.; Toth, Z.; Gutman, S.I.; King, C.W.; Gehrke, F.; Johnston, P.E.; Walls, C.; Mann, Dorte; Gottas, D.J.; Coleman, T.

    2013-01-01

    During Northern Hemisphere winters, the West Coast of North America is battered by extratropical storms. The impact of these storms is of paramount concern to California, where aging water supply and flood protection infrastructures are challenged by increased standards for urban flood protection, an unusually variable weather regime, and projections of climate change. Additionally, there are inherent conflicts between releasing water to provide flood protection and storing water to meet requirements for water supply, water quality, hydropower generation, water temperature and flow for at-risk species, and recreation. In order to improve reservoir management and meet the increasing demands on water, improved forecasts of precipitation, especially during extreme events, is required. Here we describe how California is addressing their most important and costliest environmental issue – water management – in part, by installing a state-of-the-art observing system to better track the area’s most severe wintertime storms.

  6. Extreme Energy Events Project: Construction of the detectors and installation in Italian High Schools

    CERN Document Server

    Abbrescia, M; An, S; Antolini, R; Badalà, A; Baldini Ferroli, R; Bencivenni, G; Blanco, F; Bressan, E; Chiavassa, A; Chiri, C; Cifarelli, L; Cindolo, F; Coccia, E; De Pasquale, S; Di Giovanni, A; D’Incecco, M; Fabbri, F L; Frolov, V; Garbini, M; Gustavino, C; Hatzifotiadou, D; Imponente, G; Kim, J; La Rocca, P; Librizzi, F; Maggiora, A; Menghetti, H; Miozzi, S; Moro, R; Panareo, M; Pappalardo, G S; Piragino, G; Riggi, F; Romano, F; Sartorelli, G; Sbarra, C; Selvi, M; Serci, S; Williams, C; Zuyeuski, R

    2008-01-01

    The EEE Project, conceived by its leader Antonino Zichichi, aims to detect Extreme Energy Events of cosmic rays with an array of muon telescopes distributed over the Italian territory. The Project involves Italian High Schools in order to introduce young people to Physics, also countervailing the recent crisis of university scientific classes inscriptions. The detectors for the EEE telescopes are Multigap Resistive Plate Chambers (MRPC) and have been constructed by teams of High School students who went in shift at the CERN laboratories. The mechanics and the electronics were developed by groups of researchers from CERN, the Italian Centro Fermi and INFN. The first group of schools of the EEE Project has inaugurated their telescopes recently. A status report of the Project and the preliminary results are presented.

  7. Complex network based techniques to identify extreme events and (sudden) transitions in spatio-temporal systems

    CERN Document Server

    Marwan, Norbert

    2015-01-01

    We present here two promising techniques for the application of the complex network approach to continuous spatio-temporal systems that have been developed in the last decade and show large potential for future application and development of complex systems analysis. First, we discuss the transforming of a time series from such systems to a complex network. The natural approach is to calculate the recurrence matrix and interpret such as the adjacency matrix of an associated complex network, called recurrence network. Using complex network measures, such as transitivity coefficient, we demonstrate that this approach is very efficient for identifying qualitative transitions in observational data, e.g., when analyzing paleoclimate regime transitions. Second, we demonstrate the use of directed spatial networks constructed from spatio-temporal measurements of such systems that can be derived from the synchronized-in-time occurrence of extreme events in different spatial regions. Although there are many possibiliti...

  8. EEE - Extreme Energy Events: an astroparticle physics experiment in Italian High Schools

    Science.gov (United States)

    Abbrescia, M.; Avanzini, C.; Baldini, L.; Baldini Ferroli, R.; Batignani, G.; Bencivenni, G.; Bossini, E.; Bressan, E.; Chiavassa, A.; Cicalò, C.; Cifarelli, L.; Coccia, E.; Corvaglia, A.; De Gruttola, D.; De Pasquale, S.; Di Giovanni, A.; D'Incecco, M.; Dreucci, M.; Fabbri, F. L.; Fattibene, E.; Ferrarov, A.; Forster, R.; Frolov, V.; Galeotti, P.; Garbini, M.; Gemme, G.; Gnesi, I.; Grazzi, S.; Gustavino, C.; Hatzifotiadou, D.; La Rocca, P.; Maggiora, A.; Maron, G.; Mazziotta, M. N.; Miozzi, S.; Noferini, F.; Nozzoli, F.; Panareo, M.; Panetta, M. P.; Paoletti, R.; Perasso, L.; Pilo, F.; Piragino, G.; Riggi, F.; Righini, G. C.; Rodriguez Rodriguez, A.; Sartorelli, G.; Scapparone, E.; Schioppa, M.; Scribano, A.; Selvi, M.; Serci, S.; Siddi, E.; Squarcia, S.; Taiuti, M.; Terreni, G.; Vistoli, M. C.; Votano, L.; Williams, M. C. S.; Zani, S.; Zichichi, A.; Zuyeuski, R.

    2016-05-01

    The Extreme Energy Events project (EEE) is aimed to study Extensive Air Showers (EAS) from primary cosmic rays of more than 1018 eV energy detecting the ground secondary muon component using an array of telescopes with high spatial and time resolution. The second goal of the EEE project is to involve High School teachers and students in this advanced research work and to initiate them in scientific culture: to reach both purposes the telescopes are located inside High School buildings and the detector construction, assembling and monitoring - together with data taking and analysis - are done by researchers from scientific institutions in close collaboration with them. At present there are 42 telescopes in just as many High Schools scattered all over Italy, islands included, plus two at CERN and three in INFN units. We report here some preliminary physics results from the first two common data taking periods together with the outreach impact of the project.

  9. Possible Impact of the Summer North Atlantic Oscillation on Extreme Hot Events in China

    Institute of Scientific and Technical Information of China (English)

    SUN Jian-Qi

    2012-01-01

    This paper reveals that the summer North Atlantic Oscillation (SNAO) is closely related to the extreme hot event (EHE) variability in China during the period of 1979 2009, with a positive-phase (negative-phase) SNAO corresponding to less (more) EHEs in northern China. The summer circulation anomalies associated with the SNAO give further confirmation of the above relationship. In a positive-phase (negative-phase) SNAO year, there is an anomalous cyclone (anticyclone) over central East Asia, which can increase (decrease) the total cloud cover over this region. Such changes of the total cloud cover can then decrease (increase) the solar radiation reaching the surface, which is consequently unfavorable (favorable) to the formation of EHEs over northern China.

  10. Real-time detection of an extreme scattering event: constraints on Galactic plasma lenses

    CERN Document Server

    Bannister, Keith W; Tuntsov, Artem V; Walker, Mark A; Johnston, Simon; Reynolds, Cormac; Bignall, Hayley

    2016-01-01

    Extreme scattering events (ESEs) are distinctive fluctuations in the brightness of astronomical radio sources caused by occulting plasma lenses in the interstellar medium. The inferred plasma pressures of the lenses are $\\sim 10^3$ times the ambient pressure, challenging our understanding of gas conditions in the Milky Way. Using a new survey technique, we have discovered an ESE while it was in progress. We report radio and optical follow-up observations. Modelling of the radio data demonstrates that the lensing structure is a density enhancement and that the lens is diverging, ruling out one of two competing physical models. Our technique will uncover many more ESEs, addressing a long-standing mystery of the small-scale gas structure of the Galaxy.

  11. Influence of disorder on generation and probability of extreme events in Salerno lattices

    Science.gov (United States)

    Mančić, A.; Maluckov, A.; Hadžievski, Lj.

    2017-03-01

    Extreme events (EEs) in nonlinear and/or disordered one-dimensional photonic lattice systems described by the Salerno model with on-site disorder are studied. The goal is to explain particular properties of these phenomena, essentially related to localization of light in the presence of nonlinear and/or nonlocal couplings in the considered systems. Combining statistical and nonlinear dynamical methods and measures developed in the framework of the theory of localization phenomena in disordered and nonlinear systems, particularities of EEs are qualitatively clarified. Findings presented here indicate that the best environment for EEs' creation are disordered near-integrable Salerno lattices. In addition, it is been shown that the leading role in the generation and dynamical properties of EEs in the considered model is played by modulation instability, i.e., by nonlinearities in the system, although EEs can be induced in linear lattices with on-site disorder too.

  12. Water-borne diseases and extreme weather events in Cambodia: review of impacts and implications of climate change.

    Science.gov (United States)

    Davies, Grace I; McIver, Lachlan; Kim, Yoonhee; Hashizume, Masahiro; Iddings, Steven; Chan, Vibol

    2014-12-23

    Cambodia is prone to extreme weather events, especially floods, droughts and typhoons. Climate change is predicted to increase the frequency and intensity of such events. The Cambodian population is highly vulnerable to the impacts of these events due to poverty; malnutrition; agricultural dependence; settlements in flood-prone areas, and public health, governance and technological limitations. Yet little is known about the health impacts of extreme weather events in Cambodia. Given the extremely low adaptive capacity of the population, this is a crucial knowledge gap. A literature review of the health impacts of floods, droughts and typhoons in Cambodia was conducted, with regional and global information reviewed where Cambodia-specific literature was lacking. Water-borne diseases are of particular concern in Cambodia, in the face of extreme weather events and climate change, due to, inter alia, a high pre-existing burden of diseases such as diarrhoeal illness and a lack of improved sanitation infrastructure in rural areas. A time-series analysis under quasi-Poisson distribution was used to evaluate the association between floods and diarrhoeal disease incidence in Cambodian children between 2001 and 2012 in 16 Cambodian provinces. Floods were significantly associated with increased diarrhoeal disease in two provinces, while the analysis conducted suggested a possible protective effect from toilets and piped water. Addressing the specific, local pre-existing vulnerabilities is vital to