Pub Date : 2025-01-30DOI: 10.1016/j.wace.2025.100743
Mark D. Risser , Likun Zhang , Michael F. Wehner
The last decade has seen numerous record-shattering heatwaves in all corners of the globe. In the aftermath of these devastating events, there is interest in identifying worst-case thresholds or upper bounds that quantify just how hot temperatures can become. Generalized Extreme Value theory provides a data-driven estimate of extreme thresholds; however, upper bounds may be exceeded by future events, which undermines attribution and planning for heatwave impacts. Here, we show how the occurrence and relative probability of observed yet unprecedented events that exceed a priori upper bound estimates, so-called “impossible” temperatures, has changed over time. We find that many unprecedented events are actually within data-driven upper bounds, but only when using modern spatial statistical methods. Furthermore, there are clear connections between anthropogenic forcing and the “impossibility” of the most extreme temperatures. Robust understanding of heatwave thresholds provides critical information about future record-breaking events and how their extremity relates to historical measurements.
{"title":"Data-driven upper bounds and event attribution for unprecedented heatwaves","authors":"Mark D. Risser , Likun Zhang , Michael F. Wehner","doi":"10.1016/j.wace.2025.100743","DOIUrl":"10.1016/j.wace.2025.100743","url":null,"abstract":"<div><div>The last decade has seen numerous record-shattering heatwaves in all corners of the globe. In the aftermath of these devastating events, there is interest in identifying worst-case thresholds or upper bounds that quantify just how hot temperatures can become. Generalized Extreme Value theory provides a data-driven estimate of extreme thresholds; however, upper bounds may be exceeded by future events, which undermines attribution and planning for heatwave impacts. Here, we show how the occurrence and relative probability of observed yet unprecedented events that exceed <em>a priori</em> upper bound estimates, so-called “impossible” temperatures, has changed over time. We find that many unprecedented events are actually within data-driven upper bounds, but only when using modern spatial statistical methods. Furthermore, there are clear connections between anthropogenic forcing and the “impossibility” of the most extreme temperatures. Robust understanding of heatwave thresholds provides critical information about future record-breaking events and how their extremity relates to historical measurements.</div></div>","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"47 ","pages":"Article 100743"},"PeriodicalIF":6.1,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143072650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-21DOI: 10.1016/j.wace.2024.100742
Haider Ali , Leonard Chek Yuet Wong , Andreas F. Prein , Hayley J. Fowler
Precipitation brought by cyclone systems has long been known as a major contributor to devastating flood events.Recent post-tropical cyclones (PTCs), which transform from tropical cyclones (TC) to extratropical cyclones (ETC) in the mid-latitudes, are among the strongest cyclones in the mid-latitude European region. Understanding PTCs and their precipitation behavior, particularly in the context of recent observations, is crucial for assessing and mitigating hazards effectively. Here, we couple precipitation data and best track data to examine different aspects of PTCs, such as track characteristics and the associated precipitation behavior. Using the International Best Track Archive for Climate Stewardship (IBTrACS) data from 2001 to 2020, we find that TCs and ETCs peak during fall months, especially in October, with cyclogenesis and extratropical transition (ET) locations varying seasonally. ETCs share characteristics with frontal cyclones, such as faster translation velocities and larger radii than TCs. Hourly precipitation data from Integrated Multi-satellitE Retrievals for Global precipitation measurement (IMERG) (2001–2020) shows lower intensity during ETC phases compared to TC phases but with broader areal coverage – precipitation shields -, with ETCs consistently producing more total rainfall over 24 h. The centroid of precipitation regions during ETC phases shifts northeast of the cyclone centers for short-duration rainfall and west-southwest for longer durations, indicating widespread precipitation further from the cyclone centre. We found asymmetric precipitation distributions favoring the left side of the cyclone track during ETC phases, especially for lower-intensity events. Our results provide valuable insights into the evolving nature of PTCs, and their impact on precipitation patterns, which are crucial for hazard assessment models and mitigation strategies to safeguard communities and minimize the risks associated with these potential hazards.
{"title":"Characteristics of precipitation associated with post-tropical cyclones in the North Atlantic","authors":"Haider Ali , Leonard Chek Yuet Wong , Andreas F. Prein , Hayley J. Fowler","doi":"10.1016/j.wace.2024.100742","DOIUrl":"10.1016/j.wace.2024.100742","url":null,"abstract":"<div><div>Precipitation brought by cyclone systems has long been known as a major contributor to devastating flood events.Recent post-tropical cyclones (PTCs), which transform from tropical cyclones (TC) to extratropical cyclones (ETC) in the mid-latitudes, are among the strongest cyclones in the mid-latitude European region. Understanding PTCs and their precipitation behavior, particularly in the context of recent observations, is crucial for assessing and mitigating hazards effectively. Here, we couple precipitation data and best track data to examine different aspects of PTCs, such as track characteristics and the associated precipitation behavior. Using the International Best Track Archive for Climate Stewardship (IBTrACS) data from 2001 to 2020, we find that TCs and ETCs peak during fall months, especially in October, with cyclogenesis and extratropical transition (ET) locations varying seasonally. ETCs share characteristics with frontal cyclones, such as faster translation velocities and larger radii than TCs. Hourly precipitation data from Integrated Multi-satellitE Retrievals for Global precipitation measurement <strong>(</strong>IMERG) (2001–2020) shows lower intensity during ETC phases compared to TC phases but with broader areal coverage – precipitation shields -, with ETCs consistently producing more total rainfall over 24 h. The centroid of precipitation regions during ETC phases shifts northeast of the cyclone centers for short-duration rainfall and west-southwest for longer durations, indicating widespread precipitation further from the cyclone centre. We found asymmetric precipitation distributions favoring the left side of the cyclone track during ETC phases, especially for lower-intensity events. Our results provide valuable insights into the evolving nature of PTCs, and their impact on precipitation patterns, which are crucial for hazard assessment models and mitigation strategies to safeguard communities and minimize the risks associated with these potential hazards.</div></div>","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"47 ","pages":"Article 100742"},"PeriodicalIF":6.1,"publicationDate":"2024-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-16DOI: 10.1016/j.wace.2024.100740
G.A. Torsah , M.A. Osei , J.N.A. Aryee , J.A.A. Oti , L.K. Amekudzi
Due to their rapidly changing atmospheric processes, forecasting thunderstorms resulting from the merger of isolated cells is a complex task for highly-resolved numerical weather prediction models. This study employed a novel approach to establish the processes that drive updrafts and downdrafts in the merger of isolated thunderstorm cells that produced heavy rainfall and flooding in Kumasi and other parts of the Ashanti Region during June 23–24, 2021. We examine the dynamic and thermodynamic factors to determine the processes that led to the heavy rainfall. The study confirms that the established moisture gradient between the south and north of the region leads to differential surface heating that deepens the planetary boundary layer. Additionally, colder air aloft a warmer surface induces atmospheric overturning, impacts the CAPE and produces substantial updrafts. Also, lower equivalent potential temperature values before storm events, coupled with reduced warming and moisture and increased vertical motion, especially in the mid-levels, favor dry air entrainment, thereby enhancing updraft potential in the mid-troposphere. Besides, the study found that strong rainfall during storms correlates with high soil moisture, evaporative fraction, and variable CAPE and updrafts, which prolonged surface convergence and upper-level divergence, leading to sustained convective activity and heavy rainfall. Notably, the study establishes the roles of African Easterly Waves and low-level wind shear in influencing thunderstorm updrafts and rainfall propagation. Furthermore, we found a single-cell thunderstorm with a variable wind pattern that impacted a defined path during the storm progression. These findings provide valuable information to enhance the development of early warning systems for the detection of localized thunderstorm activities during the monsoon period.
{"title":"Triggers of inland heavy rainfall inducing convective storms in West Africa : Case study of June, 2021","authors":"G.A. Torsah , M.A. Osei , J.N.A. Aryee , J.A.A. Oti , L.K. Amekudzi","doi":"10.1016/j.wace.2024.100740","DOIUrl":"10.1016/j.wace.2024.100740","url":null,"abstract":"<div><div>Due to their rapidly changing atmospheric processes, forecasting thunderstorms resulting from the merger of isolated cells is a complex task for highly-resolved numerical weather prediction models. This study employed a novel approach to establish the processes that drive updrafts and downdrafts in the merger of isolated thunderstorm cells that produced heavy rainfall and flooding in Kumasi and other parts of the Ashanti Region during June 23–24, 2021. We examine the dynamic and thermodynamic factors to determine the processes that led to the heavy rainfall. The study confirms that the established moisture gradient between the south and north of the region leads to differential surface heating that deepens the planetary boundary layer. Additionally, colder air aloft a warmer surface induces atmospheric overturning, impacts the CAPE and produces substantial updrafts. Also, lower equivalent potential temperature values before storm events, coupled with reduced warming and moisture and increased vertical motion, especially in the mid-levels, favor dry air entrainment, thereby enhancing updraft potential in the mid-troposphere. Besides, the study found that strong rainfall during storms correlates with high soil moisture, evaporative fraction, and variable CAPE and updrafts, which prolonged surface convergence and upper-level divergence, leading to sustained convective activity and heavy rainfall. Notably, the study establishes the roles of African Easterly Waves and low-level wind shear in influencing thunderstorm updrafts and rainfall propagation. Furthermore, we found a single-cell thunderstorm with a variable wind pattern that impacted a defined path during the storm progression. These findings provide valuable information to enhance the development of early warning systems for the detection of localized thunderstorm activities during the monsoon period.</div></div>","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"47 ","pages":"Article 100740"},"PeriodicalIF":6.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-09DOI: 10.1016/j.wace.2024.100741
Sebastian Pfautsch , Agnieszka Wujeska-Klause , Judi R. Walters
Rising summer heat and more frequent and intense heatwaves impact countless metropolitan regions, including Greater Sydney, Australia. An analysis of historic air temperature measurements (1859–2020) reveals a notable increase in the number of ‘hot’ (≥35 °C) days during austral summers. While in the first 120 years of records 351 hot days were identified, 478 hot days were recorded during 2000–2020 alone. Trajectories of summer heat until 2060 indicate that maximum air temperatures in Western Sydney could be ≥ 35 °C during 160 days.
A second, more granular analysis compared air temperature measurements recorded at 274 urban microsites during the summers of 2019 and 2020 with measurements of official weather stations in Central and Western Sydney. Results revealed that the number of hot (≥35 °C), extreme (≥40 °C), and ‘catastrophic’ (≥45 °C) heat days was markedly greater than those reported by official weather stations. Underreporting of heat was greatest across the Local Government Area (LGA) of Cumberland, where data loggers recorded 32 hot and 15 extreme heat days, compared to 7 hot and 1 extreme heat day recorded by the nearest official station. Based on empirical measurements, a set of novel ‘heat risk’ maps identify suburbs and regions inside LGAs where underreporting of summer heat is high. Findings indicate that communities across Greater Sydney are exposed to more frequent and more intense heat than previously reported. Underreporting of local urban heat results in lower preparedness and thus higher risk of harm to urban populations of Greater Sydney and likely many other metropolitan regions.
{"title":"Spatiotemporal variation of intra-urban heat and heatwaves across Greater Sydney, Australia","authors":"Sebastian Pfautsch , Agnieszka Wujeska-Klause , Judi R. Walters","doi":"10.1016/j.wace.2024.100741","DOIUrl":"10.1016/j.wace.2024.100741","url":null,"abstract":"<div><div>Rising summer heat and more frequent and intense heatwaves impact countless metropolitan regions, including Greater Sydney, Australia. An analysis of historic air temperature measurements (1859–2020) reveals a notable increase in the number of ‘hot’ (≥35 °C) days during austral summers. While in the first 120 years of records 351 hot days were identified, 478 hot days were recorded during 2000–2020 alone. Trajectories of summer heat until 2060 indicate that maximum air temperatures in Western Sydney could be ≥ 35 °C during 160 days.</div><div>A second, more granular analysis compared air temperature measurements recorded at 274 urban microsites during the summers of 2019 and 2020 with measurements of official weather stations in Central and Western Sydney. Results revealed that the number of hot (≥35 °C), extreme (≥40 °C), and ‘catastrophic’ (≥45 °C) heat days was markedly greater than those reported by official weather stations. Underreporting of heat was greatest across the Local Government Area (LGA) of Cumberland, where data loggers recorded 32 hot and 15 extreme heat days, compared to 7 hot and 1 extreme heat day recorded by the nearest official station. Based on empirical measurements, a set of novel ‘heat risk’ maps identify suburbs and regions inside LGAs where underreporting of summer heat is high. Findings indicate that communities across Greater Sydney are exposed to more frequent and more intense heat than previously reported. Underreporting of local urban heat results in lower preparedness and thus higher risk of harm to urban populations of Greater Sydney and likely many other metropolitan regions.</div></div>","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"47 ","pages":"Article 100741"},"PeriodicalIF":6.1,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142823155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.wace.2024.100726
S. Kim , J.-H. Kwon , J.-S. Om , T. Lee , G. Kim , H. Kim , J.-H. Heo
{"title":"Corrigendum to “Increasing extreme flood risk under future climate change scenarios in South Korea” [Weather Clim. Extrem. 39 (2023) 1–12, 100552]","authors":"S. Kim , J.-H. Kwon , J.-S. Om , T. Lee , G. Kim , H. Kim , J.-H. Heo","doi":"10.1016/j.wace.2024.100726","DOIUrl":"10.1016/j.wace.2024.100726","url":null,"abstract":"","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"46 ","pages":"Article 100726"},"PeriodicalIF":6.1,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142329785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.wace.2024.100719
Chanil Park , Min-Jee Kang , Jaeyoung Hwang , Hyeong-Oh Cho , Sujin Kim , Seok-Woo Son
{"title":"Corrigendum “Multiscale drivers of catastrophic heavy rainfall event in early August 2022 in South Korea” [Weather and Climate Extremes, 44, 2024, 1–16/10068]","authors":"Chanil Park , Min-Jee Kang , Jaeyoung Hwang , Hyeong-Oh Cho , Sujin Kim , Seok-Woo Son","doi":"10.1016/j.wace.2024.100719","DOIUrl":"10.1016/j.wace.2024.100719","url":null,"abstract":"","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"46 ","pages":"Article 100719"},"PeriodicalIF":6.1,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142275906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1016/j.wace.2024.100738
Jasmin Heilemann , Christian Klassert , Luis Samaniego , Stephan Thober , Andreas Marx , Friedrich Boeing , Bernd Klauer , Erik Gawel
Extreme weather events are recognized as major drivers of crop yield losses, which threaten food security and farmers’ incomes. Given the increasing frequency and intensity of extreme weather under climate change, it is crucial to quantify the related future yield damages of important crops to inform prospective climate change adaptation planning. In this study, we present a statistical modeling approach to project the changes in crop yields under climate change for eight majorly cultivated field crops in Germany, estimating the impacts of nine types of extreme weather events. To select the most relevant predictors, we apply the least absolute shrinkage and selection operator (LASSO) regression to district-level yield data.
The LASSO models select, on average, 62% of the features, which align with well-known biophysical impacts on crops, suggesting that different extremes at various growth stages are relevant for yield prediction. We project on average 2.5-times more severe impacts on summer crops than on winter crops. Under RCP8.5, crop yields experience a mean change from −2.53% to −8.63% in the far future (2069–98) for summer crops and from −0.80% to −2.88% for winter crops, without accounting for CO2 fertilization effects. Heat impacts are identified as the primary driver of yield losses across all crops for 2069–98, while shifting precipitation patterns exacerbate winter and spring waterlogging, and summer and fall drought.
Our findings underscore the utility of LASSO regression in identifying relevant drivers for projecting changes in crop yields across multiple crops, crucial for guiding agricultural adaptation. While the present analysis can identify empirical relationships, replicating these findings in biophysical models could provide new insights into the underlying processes.
{"title":"Projecting impacts of extreme weather events on crop yields using LASSO regression","authors":"Jasmin Heilemann , Christian Klassert , Luis Samaniego , Stephan Thober , Andreas Marx , Friedrich Boeing , Bernd Klauer , Erik Gawel","doi":"10.1016/j.wace.2024.100738","DOIUrl":"10.1016/j.wace.2024.100738","url":null,"abstract":"<div><div>Extreme weather events are recognized as major drivers of crop yield losses, which threaten food security and farmers’ incomes. Given the increasing frequency and intensity of extreme weather under climate change, it is crucial to quantify the related future yield damages of important crops to inform prospective climate change adaptation planning. In this study, we present a statistical modeling approach to project the changes in crop yields under climate change for eight majorly cultivated field crops in Germany, estimating the impacts of nine types of extreme weather events. To select the most relevant predictors, we apply the least absolute shrinkage and selection operator (LASSO) regression to district-level yield data.</div><div>The LASSO models select, on average, 62% of the features, which align with well-known biophysical impacts on crops, suggesting that different extremes at various growth stages are relevant for yield prediction. We project on average 2.5-times more severe impacts on summer crops than on winter crops. Under RCP8.5, crop yields experience a mean change from −2.53% to −8.63% in the far future (2069–98) for summer crops and from −0.80% to −2.88% for winter crops, without accounting for CO<sub>2</sub> fertilization effects. Heat impacts are identified as the primary driver of yield losses across all crops for 2069–98, while shifting precipitation patterns exacerbate winter and spring waterlogging, and summer and fall drought.</div><div>Our findings underscore the utility of LASSO regression in identifying relevant drivers for projecting changes in crop yields across multiple crops, crucial for guiding agricultural adaptation. While the present analysis can identify empirical relationships, replicating these findings in biophysical models could provide new insights into the underlying processes.</div></div>","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"46 ","pages":"Article 100738"},"PeriodicalIF":6.1,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-12DOI: 10.1016/j.wace.2024.100739
Shijie Tang , Tianjun Zhou , Lixia Zhang , Liwei Zou , Wenxia Zhang , Shijia Liu
The Taklimakan desert, situated in western China and known for its scarcity of precipitation, experienced an unprecedented precipitation event on 13-14th May 2021. However, the moisture sources and the reason for such extreme precipitation in the heart of the desert remain unexplored. Here, leveraging rain gauge observations from Tazhong Station, situated in the heartland of the Taklimakan Desert, we employed the Flexpart Lagrangian model to examine the moisture source and transport path of this exceptional precipitation event. The target region is situated east of the 500 hPa low trough and to the right of the entrance and left of the exit area of the two upper-level jet streams, providing favorable dynamic conditions for extreme precipitation. Our analysis indicates that the water vapor transport from the eastern boundary of the target area, which originates from the westerly wind along the northern side of the Tianshan Mountains and later turns southward to the Tarim Basin, was the decisive factor for this extreme precipitation event. By employing the Flexpart model, we found that the east particles, which bypassed the Tianshan Mountains and entered the target from its eastern boundary contributed 61.7% of the precipitation, while the west particles contributed only 38.3%. Regarding overall moisture sources, southern Xinjiang emerged as the most significant contributor, accounting for 43.0% of the water vapor, followed by northern Xinjiang at 24.7%, and Central Asia at 21.2%. Our findings suggest that water vapor conditions play a more critical role than dynamic factors in driving such extreme precipitation events in the target area. The water vapor associated with the extreme precipitation event in the target area primarily originates from Southern Xinjiang and its adjacent regions. These results can help us improve the understanding of the mechanism behind extreme precipitation events in arid areas, especially in desert areas.
{"title":"Moisture sources for the unprecedented precipitation event in the heart of Taklimakan desert","authors":"Shijie Tang , Tianjun Zhou , Lixia Zhang , Liwei Zou , Wenxia Zhang , Shijia Liu","doi":"10.1016/j.wace.2024.100739","DOIUrl":"10.1016/j.wace.2024.100739","url":null,"abstract":"<div><div>The Taklimakan desert, situated in western China and known for its scarcity of precipitation, experienced an unprecedented precipitation event on 13-14th May 2021. However, the moisture sources and the reason for such extreme precipitation in the heart of the desert remain unexplored. Here, leveraging rain gauge observations from Tazhong Station, situated in the heartland of the Taklimakan Desert, we employed the Flexpart Lagrangian model to examine the moisture source and transport path of this exceptional precipitation event. The target region is situated east of the 500 hPa low trough and to the right of the entrance and left of the exit area of the two upper-level jet streams, providing favorable dynamic conditions for extreme precipitation. Our analysis indicates that the water vapor transport from the eastern boundary of the target area, which originates from the westerly wind along the northern side of the Tianshan Mountains and later turns southward to the Tarim Basin, was the decisive factor for this extreme precipitation event. By employing the Flexpart model, we found that the east particles, which bypassed the Tianshan Mountains and entered the target from its eastern boundary contributed 61.7% of the precipitation, while the west particles contributed only 38.3%. Regarding overall moisture sources, southern Xinjiang emerged as the most significant contributor, accounting for 43.0% of the water vapor, followed by northern Xinjiang at 24.7%, and Central Asia at 21.2%. Our findings suggest that water vapor conditions play a more critical role than dynamic factors in driving such extreme precipitation events in the target area. The water vapor associated with the extreme precipitation event in the target area primarily originates from Southern Xinjiang and its adjacent regions. These results can help us improve the understanding of the mechanism behind extreme precipitation events in arid areas, especially in desert areas.</div></div>","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"46 ","pages":"Article 100739"},"PeriodicalIF":6.1,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1016/j.wace.2024.100737
Jun Su , Yihui Ding , Yanju Liu , Jing Wang , Yingxian Zhang
Drought to flood abrupt alternation (DFAA) events, as a special category of compound extreme events that suddenly shift from drought to flood conditions, have significantly greater impacts than individual drought or flood events. In this paper, we have utilized a multifactorial drought index and flood index to identify daily DFAA events occurring in mainland China and in major impact areas during the period 1961–2022. Based on drought and flood index, we have used entropy weighting method to measure the intensity of DFAA events. Our findings indicate that China's DFAA events primarily occur in the hotspots of Huang-Huai-Hai River Basin, the middle and lower Yangtze River Basin, the southeastern coastal area, and the southwestern part of the country. The most frequent and intense DFAA events occur from June to September, with varying subseasonal patterns in the frequency and intensity of events in each hotspot. The frequency of DFAA events in mainland China shows a significant decreasing trend declining at a rate of 0.25 per year in year-round. While DFAA events occurring in the warm season tend to decrease more significantly compared to the year-round at a rate of 0.26 per year. However, the intensity of DFAA events is increasing with a rate of 0.1 per decade in both the year-round and warm season. The evolution of DFAA events and their direct causes varies non-uniformly across regions and months. Subseasonally, frequency and intensity trends diverged monthly across regions, notably with the Huang-Huai-Hai Basin and southeast coast experiencing a July decline in frequency but a surge in intensity. Our research deepens the understanding of changes in DFAA events and provides practical reference for preventing and mitigating drought-to-flood disasters in mainland China.
{"title":"China is suffering from fewer but more severe drought to flood abrupt alternation events","authors":"Jun Su , Yihui Ding , Yanju Liu , Jing Wang , Yingxian Zhang","doi":"10.1016/j.wace.2024.100737","DOIUrl":"10.1016/j.wace.2024.100737","url":null,"abstract":"<div><div>Drought to flood abrupt alternation (DFAA) events, as a special category of compound extreme events that suddenly shift from drought to flood conditions, have significantly greater impacts than individual drought or flood events. In this paper, we have utilized a multifactorial drought index and flood index to identify daily DFAA events occurring in mainland China and in major impact areas during the period 1961–2022. Based on drought and flood index, we have used entropy weighting method to measure the intensity of DFAA events. Our findings indicate that China's DFAA events primarily occur in the hotspots of Huang-Huai-Hai River Basin, the middle and lower Yangtze River Basin, the southeastern coastal area, and the southwestern part of the country. The most frequent and intense DFAA events occur from June to September, with varying subseasonal patterns in the frequency and intensity of events in each hotspot. The frequency of DFAA events in mainland China shows a significant decreasing trend declining at a rate of 0.25 per year in year-round. While DFAA events occurring in the warm season tend to decrease more significantly compared to the year-round at a rate of 0.26 per year. However, the intensity of DFAA events is increasing with a rate of 0.1 per decade in both the year-round and warm season. The evolution of DFAA events and their direct causes varies non-uniformly across regions and months. Subseasonally, frequency and intensity trends diverged monthly across regions, notably with the Huang-Huai-Hai Basin and southeast coast experiencing a July decline in frequency but a surge in intensity. Our research deepens the understanding of changes in DFAA events and provides practical reference for preventing and mitigating drought-to-flood disasters in mainland China.</div></div>","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"46 ","pages":"Article 100737"},"PeriodicalIF":6.1,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-18DOI: 10.1016/j.wace.2024.100736
Thomas H. Ford
Most droughts go unnamed. At the time they are happening, they are generally referred to simply as “the drought.” After the fact, they are typically designated by a year or run of years rather than by a name: 1927–29, for instance. But in recent decades, proper names have increasingly been bestowed on droughts in southeast Australia in an informal although widely accepted practice. Examples include the Federation Drought, the World War II Drought, the Millennium Drought and, most recently, the Tinderbox Drought. This paper positions the practice of naming droughts within a longer history of naming weather extremes. It examines the implications of the naming practice for the investigation of droughts as complex objects of interdisciplinary knowledge that call for analysis from across the sciences, social sciences and humanities. And it considers the qualities and meanings attributed to the drought of 2017-19 by the name “Tinderbox.” Using the word “tinderbox” to describe environmental conditions has been criticised for naturalizing landscape flammability and so effacing human agency. But in fact the name “Tinderbox Drought” potentially enacts a semantic reversal that allows human-caused climate change to be reassociated discursively with recent and future drought events.
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