New York City Panel on Climate Change 2015 Report. Chapter 1: Climate observations and projections.

Appendix II: NPCC 2015 technical details.

Detection and attribution of extreme precipitation changes from 1961 to 2012 in the Yangtze River Delta in China

Both large-scale atmospheric circulation and moisture content in the atmosphere govern regional precipitation. We partition recent changes in mean, heavy, and extreme precipitation for all seasons over Canada to changes in synoptic circulation patterns (dynamic changes) and in atmospheric moisture conditions (thermodynamic changes) using 500-hPa geopotential height and precipitation data over 1979–2014. Using the self-organizing map (SOM) cluster analysis, we identify statistically significant trends in occurrences of certain synoptic circulation patterns over the Canadian landmass, which have dynamically contributed to observed changes in precipitation totals and occurrence of heavy and extreme precipitation events over Canada. Occurrences of circulation patterns such as westerlies and ridges over western North America and the North Pacific have considerably affected regional precipitation over Canada. Precipitation intensity and occurrences of precipitation extremes associated with each SOM circulation pattern also showed statistically significant trends resulting from thermodynamic changes in the atmospheric moisture supply for precipitation events. A partition analysis based on the thermodynamic–dynamic partition method indicates that most (~90%) changes in mean and extreme precipitation over Canada resulted from changes in precipitation regimes occurring under each synoptic circulation pattern (thermodynamic changes). Other regional precipitation changes resulted from changes in occurrences of synoptic circulation patterns (dynamic changes). Because of the high spatial variability of precipitation response to changes in thermodynamic and dynamic conditions, dynamic contributions could offset thermodynamic contributions to precipitation changes over some regions if thermodynamic and dynamic contributions are in opposition to each other (negative or positive), which would result in minimal changes in precipitation intensity and occurrences of heavy and extreme precipitation events.

William Solecki,1,a Cynthia Rosenzweig,2,a Reginald Blake,3,a Alex de Sherbinin,4 Tom Matte,5 Fred Moshary,6 Bernice Rosenzweig,7 Mark Arend,6 Stuart Gaffin,8 Elie Bou-Zeid,9 Keith Rule,10 Geraldine Sweeny,11 and Wendy Dessy11 1City University of New York, CUNY Institute for Sustainable Cities, New York, NY. 2Climate Impacts Group, NASA Goddard Institute for Space Studies, Center for Climate Systems Research, Columbia University Earth Institute, New York, NY. 3Physics Department, New York City College of Technology, CUNY, Brooklyn, NY; Climate Impacts Group, NASA Goddard Institute for Space Studies. 4 Center for International Earth Science Information Network (CIESIN), Columbia University, Palisades, NY. 5New York City Department of Health and Mental Hygiene, New York, NY. 6NOAA CREST, City College of New York, CUNY, New York, NY. 7CUNY Environmental Crossroads, City College of New York, CUNY, New York, NY. 8Center for Climate Systems Research, Columbia University Earth Institute, New York, NY. 9Department of Civil & Environmental Engineering, Princeton University, Princeton, NJ. 10Princeton Plasma Physics Laboratory, Princeton, NJ. 11New York City Mayor’s Office of Operation, New York, NY

Under the conditions of climate change, extreme events occur more frequently with higher energy for devastation. Planning for effective management of climate-related risks demands clear information at the local scale. This study aims to characterize the extreme events in the daily precipitation records and to assess the changes under future climate conditions in flood vulnerable city of Adama. For this, the extreme rainfall events during 1965 and 2016 were analyzed on the basis of 10 selected extreme precipitation indices. Using a statistical downscaling model (SDSM), future daily precipitation in the city for the period 2021–2080 was downscaled from the outputs of two Global Circulation Models (CanESM2 and HadCM3) under five climate change scenarios. Taking the climate conditions during 1971 and 2000 as a base, changes in precipitation extreme events in future periods (2021–2050 and 2051–2080) were investigated using the delta approach. The study reveals that the extreme precipitation events in Adama city were increasing over the period of 1965–2016. The results also indicate a successful application of the SDSM for downscaling local-scale future daily precipitation from the outputs of large-scale atmospheric information for the study area. Moreover, under future climate change scenarios, the extreme precipitation would increase up to 2080, despite the changes will be highest during 2050 and 2080, indicates the study area could experience frequent and more severe floods during the coming 60 years due to the changes in global climate. This study would support planning for effective management of flood risks due to the impacts of climate change on extreme precipitation in Adama city.

Review of <i>Floods in a Changing Climate: Extreme Precipitation</i> by Ramesh S. V. TeegavarapuCambridge University Press, New York; 2013; ISBN 978-1-107-01878-5; 285 pp., $120.00.

در این مطالعه، به بررسی تغییر پذیری و تحلیل نوسان های بارش های حدی غرب و شمال غرب کشور با استفاده از آزمون های آماری تحلیل طیفی و من کندال در نیم سده گذشته پرداخته شده است. فراسنج‌های مورد مطالعه عبارتند از نمایه‌های دور پیوندی NAO، AO، ENSO و MEI، کلف‌های خورشیدی و مراکز فشار شامل کم‌فشار مدیترانه، کم‌فشار دریای سیاه، کم‌فشار سودان و پرفشار سیبری است. بدین منظور از 8 ایستگاه همدید، که دارای آمار 50 سال اخیر (1961-2010) هستند، و همچنین از 10 نمایه حدی بارش استفاده شده است. نتایج نشان می‌دهد که تنها در ایستگاه سنندج روند نمایه های حدی بارش افزایشی بوده است. گرچه برخی از نمایه‌ها در ایستگاه‌هایی محدود دارای روندی افزایشی بوده اند، اما بطور کلی نتایج نشان می‌دهد که بارش‌های حدی این منطقه در طی 50 سال گذشته دارای روندی کاهشی است که این روند کاهشی در ارتباط با رفتار نمایه‌های دورپیوندی AO، NAO و ENSO و همچنین مراکز فشار تأثیرگذار بر بارش منطقه اعم از پرفشار سیبری، کم فشار سودانی و کم فشار مدیترانه است و سبب کاهش در بارش ها در غرب و شمال غرب کشور می شوند. نتایج تحلیل طیفی نشان می دهد که چرخه فرین های بارش در درجه اول در ارتباط با چرخه شدت و ضعف مرکز کم فشار مدیترانه و چرخه های 2 تا 3 ساله آن است. همچنین در بین نمایه های دور پیوندی، بیش از همه چرخه بارش های حدی در ارتباط با چرخه 3 تا 5 ساله نمایه انسو می باشد، بگونه ای که در تمام ایستگاه ها نمایه انسو با بارش های حدی منطقه مورد مطالعه دارای ارتباط است. لازم به توضیح است که تأثیر کلف های خورشیدی بر بارش های منطقه مورد مطالعه بسیار محدود بوده و تنها در ایستگاه ارومیه، چرخه نمایه مقدار سالانه بارش روزهای تر متناظر با چرخه 11 ساله لکه های خورشیدی می باشد.

This study investigates likely changes in mean and extreme precipitation over southern Africa in response to changes in radiative forcing using an ensemble of global climate models prepared for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). Extreme seasonal precipitation is defined in terms of 10-yr return levels obtained by inverting a generalized Pareto distribution fitted to excesses above a predefined high threshold. Both present (control) and future climate precipitation extremes are estimated. The future-to-control climate ratio of 10-yr return levels is then used as an indicator for the likely changes in extreme seasonal precipitation. A Bayesian approach to multimodel ensembling is adopted. The relative weights assigned to each of the model simulations is determined from bias, convergence, and correlation. Using this method, the probable limits of the changes in mean and extreme precipitation are estimated from their posterior distribution. Over the western parts of southern Africa, an increase in the severity of dry extremes parallels a statistically significant decrease in mean precipitation during austral summer months. A notable delay in the onset of the rainy season is found in almost the entire region. An early cessation is found in many parts. This implies a statistically significant shortening of the rainy season. A substantial reduction in moisture influx from the southwestern Indian Ocean during austral spring is projected. This and the preaustral spring moisture deficits are possible mechanisms delaying the rainfall onset in southern Africa. A possible offshore (northeasterly) shift of the tropical–temperate cloud band is consistent with more severe droughts in the southwest of southern Africa and enhanced precipitation farther north in Zambia, Malawi, and northern Mozambique. This study shows that changes in the mean vary on relatively small spatial scales in southern Africa and differ between seasons. Changes in extremes often, but not always, parallel changes in the mean precipitation.

This study investigates likely changes in mean and extreme precipitation over southern Africa in response to changes in radiative forcing using an ensemble of global climate models prepared for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). Extreme seasonal precipitation is defined in terms of 10-yr return levels obtained by inverting a generalized Pareto distribution fitted to excesses above a predefined high threshold. Both present (control) and future climate precipitation extremes are estimated. The future-to-control climate ratio of 10-yr return levels is then used as an indicator for the likely changes in extreme seasonal precipitation. A Bayesian approach to multimodel ensembling is adopted. The relative weights assigned to each of the model simulations is determined from bias, convergence, and correlation. Using this method, the probable limits of the changes in mean and extreme precipitation are estimated from their posterior distribution. Over the western parts of southern Africa, an increase in the severity of dry extremes parallels a statistically significant decrease in mean precipitation during austral summer months. A notable delay in the onset of the rainy season is found in almost the entire region. An early cessation is found in many parts. This implies a statistically significant shortening of the rainy season. A substantial reduction in moisture influx from the southwestern Indian Ocean during austral spring is projected. This and the preaustral spring moisture deficits are possible mechanisms delaying the rainfall onset in southern Africa. A possible offshore (northeasterly) shift of the tropical–temperate cloud band is consistent with more severe droughts in the southwest of southern Africa and enhanced precipitation farther north in Zambia, Malawi, and northern Mozambique. This study shows that changes in the mean vary on relatively small spatial scales in southern Africa and differ between seasons. Changes in extremes often, but not always, parallel changes in the mean precipitation.

Introduction: Several studies have shown associations between an increase in precipitation and a higher frequency of traffic accidents; a few have examined the relationship between high temperatures and motor vehicle crashes. However, to our knowledge, no studies exist assessing how extreme events, projected to grow in frequency, intensity, and duration in response to our changing climate, will impact the risk of injury from motor vehicle accidents. Our study quantified the association between frequency of extreme heat and precipitation events and change in injury risk from motor vehicle accident in Maryland between 2000 and 2012. Methods: Motor vehicle accident data was obtained from the Maryland Automated Accident Reporting System. Each observation in the data set corresponded to a unique collision event. A time-stratified case-crossover design was utilized to assess the association between exposure to extreme heat and precipitation events and risk of injury or death from motor vehicle accident. Additional stratified analyses examined risk by road type and season. Results: Over the study period, there were 461,009 motor vehicle accidents that resulted in injury or death. We observed an 18% increase (OR: 1.18; 95% CI: 1.17, 1.19) in risk of motor vehicle injury for every 1-day increase in extreme precipitation event, with the highest risk (29%) observed during autumn (OR: 1.29; 95% CI: 1.27, 1.32). Extreme precipitation related increase in motor vehicle injury was considerably higher when a road defect or obstruction was present (OR: 1.42, 95% CI: 1.32, 1.52). Changes in risk associated with extreme heat events were generally marginal. Conclusion: Extreme precipitation events, particularly in conjunction with a road defect or obstruction, are associated with an increased risk of injury from motor vehicle accidents in Maryland. Our results suggest that projected increases in frequency of extreme precipitation event will have a significant impact on public health.

&amp;lt;p&amp;gt;In the context of global warming, frequent extreme climate events, especially high temperature heat waves and global warming, lead to an increase in the frequency and intensity of heat waves. At the same time, due to changes in climatic and hydrological characteristics, extreme precipitation and drought events closely related to people's lives frequently occur. This research studies the heat waves and extreme precipitation events from 1971 to 2020 in the Mediterranean coast of Spain, mainly in the Barcelona metropolitan area, and analyzes their main causes and influencing factors. It is of great significance to formulate improved policies and protection mechanisms in the future to promote sustainable urban development. We selected 8 different meteorological observatories as primary climate data sources in the provinces of Barcelona and Valencia, Alicante, Murcia and Almeria respectively. Using the OLS model, we estimated the global warming at each temperature by the cosine formula &amp;lt;strong&amp;gt;&amp;lt;img src=&amp;quot;https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.81b0277afdd167257391461/sdaolpUECMynit/22UGE&amp;amp;app=m&amp;amp;a=0&amp;amp;c=c47a45e6fc9b33354d9479cd81e3d03b&amp;amp;ct=x&amp;amp;pn=gnp.elif&amp;amp;d=1&amp;quot; alt=&amp;quot;&amp;quot; width=&amp;quot;122&amp;quot; height=&amp;quot;43&amp;quot;&amp;gt;&amp;amp;#160; &amp;amp;#160;&amp;lt;/strong&amp;gt;&amp;amp;#160;from the analysis of the daily average temperature, maximum temperature, and minimum temperature for each observation point. As a result, stations with higher average temperatures had lower estimates of their warming. The performance of global warming varies greatly between day and night, and is more pronounced at night than during the day. Raval is the only sample with negative values. We taken 1971-2000 as the observation period, and use the 95% percentile to judge extreme climate. It was found that the frequency of heat waves increased year by year, and the number of heat waves occurred at night was significantly higher than that during the day. The precipitation on a heat wave night is generally higher than that on a heat wave day, but the heat wave is usually accompanied by drought. However high humidity is high during the heatwave in central Barcelona. The occurrence of extreme precipitation decreases, with a higher density of heavy rainfall in the southern region than in Barcelona. In addition, extreme precipitation has made an outstanding contribution to the annual precipitation, up to 88.47%. Finally, various regression models are established to analyze the possible factors affecting extreme climate. High latitudes and long distances from the sea promote heatwaves during the day and can also prolong the number of days that they last. Heatwave nights are more frequent in high latitudes, but staying away from the ocean and high altitude can improve it. In addition, global warming and precipitation are supporting factors for high temperature heat waves. The frequency of extreme precipitation is directly proportional with latitude and mean precipitation, and is inversely correlated with distance and altitude from the sea and daily maximum temperature. There is no obvious relationship between extreme precipitation and daily maximum precipitation.&amp;lt;/p&amp;gt;

Introduction: Increasing body of literature suggests frequency, duration, and intensity of extreme events are rising and will increase in response to changing climate. Others have linked such extreme events with adverse health outcomes. Large-scale weather phenomenon (i.e., ENSO) is known to impact US weather patterns, but no studies to date have investigated how ENSO may modulate the associations between extreme events and adverse health outcomes. Methods: We linked hospitalization records for asthma/MI and culture-confirmed campylobacter/salmonella infections with extreme heat and precipitation events in Maryland. Extreme events were identified based on local climatology specific to each county derived from a 30-year baseline. We obtained data on phases of ENSO (El Niño, La Niña, Neutral) from the National Weather Service Climate Prediction Center. A time-stratified case-crossover design was used to examine associations between exposure to extreme events exposure and chronic health outcomes, while infection risk was assessed using multivariate negative binomial regression. We used stratified analysis to investigate how associations varied by ENSO phase. Results: There were 116,470 asthma and 138,343 MI hospitalizations and 4,804 and 9,527 reported infections of campylobacter and salmonella, respectively, during the study periods. Risk of salmonella and campylobacter associated with extreme heat and precipitation events was highest during the La Niña period. For asthma, risk associated with extreme heat and precipitation events was highest during El Niño. For MI, extreme heat related risk was highest during El Niño, while extreme precipitation related risk was highest during La Niña. Conclusion: Our results show extreme heat and precipitation related risk varies considerably during ENSO phases, which has a strong but uneven influence on weather across the globe. Studies investigating the link between climate change and health need to account for this phenomenon.

Contribution of extreme daily precipitation to total rainfall over the Arabian Peninsula

BackgroundSeveral studies have investigated the association between asthma exacerbations and exposures to ambient temperature and precipitation. However, limited data exists regarding how extreme events, projected to grow in frequency, intensity, and duration in the future in response to our changing climate, will impact the risk of hospitalization for asthma. The objective of our study was to quantify the association between frequency of extreme heat and precipitation events and increased risk of hospitalization for asthma in Maryland between 2000 and 2012.MethodsWe used a time-stratified case-crossover design to examine the association between exposure to extreme heat and precipitation events and risk of hospitalization for asthma (ICD-9 code 493, n = 115,923).ResultsOccurrence of extreme heat events in Maryland increased the risk of same day hospitalization for asthma (lag 0) by 3 % (Odds Ratio (OR): 1.03, 95 % Confidence Interval (CI): 1.00, 1.07), with a considerably higher risk observed for extreme heat events that occur during summer months (OR: 1.23, 95 % CI: 1.15, 1.33). Likewise, summertime extreme precipitation events increased the risk of hospitalization for asthma by 11 % in Maryland (OR: 1.11, 95 % CI: 1.06, 1.17). Across age groups, increase in risk for asthma hospitalization from exposure to extreme heat event during the summer months was most pronounced among youth and adults, while those related to extreme precipitation event was highest among ≤4 year olds.ConclusionExposure to extreme heat and extreme precipitation events, particularly during summertime, is associated with increased risk of hospitalization for asthma in Maryland. Our results suggest that projected increases in frequency of extreme heat and precipitation event will have significant impact on public health.Electronic supplementary materialThe online version of this article (doi:10.1186/s12940-016-0142-z) contains supplementary material, which is available to authorized users.

Changes in extreme precipitation in East Asia during the spring and Mei-yu seasons under global warming are evaluated based on two sets of high-resolution simulations with various warming pattern of sea surface temperature changes (SST' spa). In the spring season, extreme precipitation exhibits larger enhancements over the northern flank of the prevailing rainy region in conjunction with a shifting tendency of more frequent extreme precipitation events and northward enhancement in the probability distribution, indicating a northward extension of future spring rainband. Enhanced precipitation intensity in conjunction with less rainfall occurrence and prolonged consecutive dry days lead to a minor change in mean precipitation, implying a more difficult water resource management in the warmer climate. The projected enhancement in precipitation intensity is robust compared with the internal variability related to initial conditions and the uncertainty caused by SST'spa. In the Mei-yu season, extreme precipitation is intensified with a distribution of more frequent and more intense extreme events over the prevailing rainband region. The thermodynamic component of moisture flux predominantly contributes to changes in the spring season while both the thermodynamic and dynamic components of moisture flux contribute to the enhanced moisture transport furnishing the intensification of Mei-yu extreme precipitation from southern China to northeast Asia. Projecting future Mei-yu precipitation change is more difficult because of its higher uncertainty associated with 1) the larger variability embedded in the projection of extreme precipitation and 2) the model mean state that determines the spatial distribution of precipitation enhancement.&amp;#160;