Compound climate extremes have significant societal and ecological impacts, yet their drivers in tropical regions remain poorly understood. For example, although global evidence increasingly highlights interactions between heatwaves and precipitation, the specific mechanisms driving these compound events in Northern Australia remain poorly characterized, particularly the contrasting influence of atmospheric circulation and temperature-driven thermodynamic processes. Motivated by these gaps, this study investigates the interaction between heatwaves and precipitation bursts in Northern Australia during the pre- and post-monsoon seasons. We employ a vertically integrated moisture budget framework to systematically contrast precipitation bursts preceded by heatwaves with those occurring independently. Heatwave-associated bursts exhibit stronger and more prolonged convective activity, resulting in intensified peak precipitation and delayed maxima compared to independently occurring bursts. Vertical moisture advection is the dominant mechanism, accounting for over 70% of the variability in column-integrated moisture flux. A further decomposition reveals that the dynamic component of vertical advection — driven by circulation anomalies — plays a more substantial role than the thermodynamic component in driving these changes. These events coincide with anomalously low mean sea level pressure and enhanced cyclonic circulation, and are observed alongside sustained convective processes. Collectively, our findings highlight the role of atmospheric circulation in shaping these compounded heat and precipitation extremes in tropical Northern Australia.
{"title":"Precipitation bursts in northern Australia with and without preceding heatwaves","authors":"Sarthak Mohanty , Nikhil Garg , Nandini Ramesh , Mahesh Prakash","doi":"10.1016/j.wace.2025.100845","DOIUrl":"10.1016/j.wace.2025.100845","url":null,"abstract":"<div><div>Compound climate extremes have significant societal and ecological impacts, yet their drivers in tropical regions remain poorly understood. For example, although global evidence increasingly highlights interactions between heatwaves and precipitation, the specific mechanisms driving these compound events in Northern Australia remain poorly characterized, particularly the contrasting influence of atmospheric circulation and temperature-driven thermodynamic processes. Motivated by these gaps, this study investigates the interaction between heatwaves and precipitation bursts in Northern Australia during the pre- and post-monsoon seasons. We employ a vertically integrated moisture budget framework to systematically contrast precipitation bursts preceded by heatwaves with those occurring independently. Heatwave-associated bursts exhibit stronger and more prolonged convective activity, resulting in intensified peak precipitation and delayed maxima compared to independently occurring bursts. Vertical moisture advection is the dominant mechanism, accounting for over 70% of the variability in column-integrated moisture flux. A further decomposition reveals that the dynamic component of vertical advection — driven by circulation anomalies — plays a more substantial role than the thermodynamic component in driving these changes. These events coincide with anomalously low mean sea level pressure and enhanced cyclonic circulation, and are observed alongside sustained convective processes. Collectively, our findings highlight the role of atmospheric circulation in shaping these compounded heat and precipitation extremes in tropical Northern Australia.</div></div>","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"51 ","pages":"Article 100845"},"PeriodicalIF":6.9,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145730861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-11DOI: 10.1016/j.wace.2025.100846
Paul A. Davies , David L.A. Flack , Jennifer S.R. Pirret , Hayley J. Fowler
This study investigates the environmental conditions that resulted in the extreme rainfall and flash floods in the United Arab Emirates and Oman: 14–16 April 2024. We use a combination of numerical weather prediction modelling and observational analysis to examine the dynamics and thermodynamics of the event. Moisture convergence in the lower troposphere and a cut-off low pressure vortex coupled with high pressure over the northern Arabian Sea funnelled warm, moist air towards the Arabian Gulf. These dynamics lead to an environment that is not particularly unstable, but it is saturated in depth, with moist absolute unstable layers (MAULs) in and around areas of extreme rainfall.
We apply the concept of normalized gross moist stability alongside a recently proposed four-stage conceptual model in a spatial context. We identify large-scale indicators useful for augmenting forecast models, finding an association between MAUL depth, saturation fraction, and total rainfall. The presence of deep MAULs and a saturation fraction close to one are prerequisites for heavy rainfall enhancement in the hours preceding and during the rainfall peak.
We propose a new method to predict the characteristics of an extreme rainfall event using both the presence of MAULs and saturation fraction as a proxy for extremes, as either one on their own is not as beneficial. We infer that together these predictors can be used to discriminate between embedded convection in fronts versus isolated convective events producing the extremes.
{"title":"Application of the Davies four-stage conceptual model for life-threatening rainfall extremes on the April 2024 United Arab Emirates and Oman floods","authors":"Paul A. Davies , David L.A. Flack , Jennifer S.R. Pirret , Hayley J. Fowler","doi":"10.1016/j.wace.2025.100846","DOIUrl":"10.1016/j.wace.2025.100846","url":null,"abstract":"<div><div>This study investigates the environmental conditions that resulted in the extreme rainfall and flash floods in the United Arab Emirates and Oman: 14–16 April 2024. We use a combination of numerical weather prediction modelling and observational analysis to examine the dynamics and thermodynamics of the event. Moisture convergence in the lower troposphere and a cut-off low pressure vortex coupled with high pressure over the northern Arabian Sea funnelled warm, moist air towards the Arabian Gulf. These dynamics lead to an environment that is not particularly unstable, but it is saturated in depth, with moist absolute unstable layers (MAULs) in and around areas of extreme rainfall.</div><div>We apply the concept of normalized gross moist stability alongside a recently proposed four-stage conceptual model in a spatial context. We identify large-scale indicators useful for augmenting forecast models, finding an association between MAUL depth, saturation fraction, and total rainfall. The presence of deep MAULs and a saturation fraction close to one are prerequisites for heavy rainfall enhancement in the hours preceding and during the rainfall peak.</div><div>We propose a new method to predict the characteristics of an extreme rainfall event using both the presence of MAULs and saturation fraction as a proxy for extremes, as either one on their own is not as beneficial. We infer that together these predictors can be used to discriminate between embedded convection in fronts versus isolated convective events producing the extremes.</div></div>","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"51 ","pages":"Article 100846"},"PeriodicalIF":6.9,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145730868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-10DOI: 10.1016/j.wace.2025.100844
Ting Lv , Haiqing Yu , Hui Wang , Yingtao Zhu , Lv Lu
Accurate forecasting of typhoon-induced wave height (WH), which supports timely evacuation and informed emergency responses, is essential for the effectiveness of early warning systems. Despite recent advances in deep learning for WH forecasting, a critical gap persists: current models often fail to reliably predict rare but catastrophic extreme WH under typhoon conditions due to data scarcity. To address this challenge, we propose a physics-guided multi-scale attention framework, named the typhoon-induced wave height network (TWHN), which adopts a dual-branch architecture that separately captures wind sea and swell features. Unlike architectures that rely on initial WH inputs, TWHN forecasts WH directly from historical wind fields, thereby reducing error accumulation and supporting predictions at future time steps. To enhance the representation of extreme WH events, we introduce a tail-aware extreme value optimization (TEVO) strategy, which integrates a progressive training scheme to shift model focus from global patterns to tail data and a quantile-aware hybrid loss to penalize underestimation of high-magnitude waves. Additionally, a feature distribution smoothing mechanism is employed to stabilize training in data-sparse regimes by mitigating feature dominance from frequent samples. The model is trained, validated, and tested on WH records from 1982 to 2022, using a reanalysis dataset that includes 1 060 typhoons in the Northwest Pacific. Evaluation based on regional fields and nearshore station comparisons suggests that TWHN maintains strong potential for forecasting high-impact typhoon wave events. This work may provide implications for the advancement of operational wave forecasting and the support of risk decision-making in response to typhoon-induced marine hazards.
{"title":"A dual-branch typhoon-induced wave height forecasting network with tail-aware extreme value optimization","authors":"Ting Lv , Haiqing Yu , Hui Wang , Yingtao Zhu , Lv Lu","doi":"10.1016/j.wace.2025.100844","DOIUrl":"10.1016/j.wace.2025.100844","url":null,"abstract":"<div><div>Accurate forecasting of typhoon-induced wave height (WH), which supports timely evacuation and informed emergency responses, is essential for the effectiveness of early warning systems. Despite recent advances in deep learning for WH forecasting, a critical gap persists: current models often fail to reliably predict rare but catastrophic extreme WH under typhoon conditions due to data scarcity. To address this challenge, we propose a physics-guided multi-scale attention framework, named the typhoon-induced wave height network (TWHN), which adopts a dual-branch architecture that separately captures wind sea and swell features. Unlike architectures that rely on initial WH inputs, TWHN forecasts WH directly from historical wind fields, thereby reducing error accumulation and supporting predictions at future time steps. To enhance the representation of extreme WH events, we introduce a tail-aware extreme value optimization (TEVO) strategy, which integrates a progressive training scheme to shift model focus from global patterns to tail data and a quantile-aware hybrid loss to penalize underestimation of high-magnitude waves. Additionally, a feature distribution smoothing mechanism is employed to stabilize training in data-sparse regimes by mitigating feature dominance from frequent samples. The model is trained, validated, and tested on WH records from 1982 to 2022, using a reanalysis dataset that includes 1 060 typhoons in the Northwest Pacific. Evaluation based on regional fields and nearshore station comparisons suggests that TWHN maintains strong potential for forecasting high-impact typhoon wave events. This work may provide implications for the advancement of operational wave forecasting and the support of risk decision-making in response to typhoon-induced marine hazards.</div></div>","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"51 ","pages":"Article 100844"},"PeriodicalIF":6.9,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145730872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-06DOI: 10.1016/j.wace.2025.100843
Md. Babul Miah , Jong-Yeon Park , Min-Uk Lee , Woojin Jeon , Young-Hwa Byun , Hyun Min Sung , Jin Gi Hong , Md. Jalal Uddin , Sanjit Kumar Mondal
The Global Monsoon Areas (GMAs), home to over half of the world's population, face escalating socio-economic risks from extreme precipitation events intensified by rising atmospheric carbon dioxide (CO2). While previous studies have examined the irreversibility of the climate system following carbon neutrality, most have focused on single carbon neutrality scenarios with limited attention to these vulnerable areas. This study assesses the irreversibility of extreme precipitation intensity across seven GMA sub-regions under eight future scenarios, incorporating four carbon neutrality targets and two reduction rates, using simulations from a state-of-the-art climate model. Our results reveal that extreme precipitation intensity exhibits irreversible behavior in response to carbon neutrality forcing, failing to return to its initial level even when atmospheric CO2 is reduced. This irreversibility is particularly pronounced when carbon neutrality timing is delayed, and the emission reduction rate is slow. Moreover, the irreversible response is nonlinear to the magnitude of carbon forcing, leading to distinct regional vulnerabilities, with some areas experiencing sharp increases in irreversibility by even small delays in reaching carbon neutrality. This region-specific behavior is largely attributed to increases in mean and variability of precipitation linked to irreversible El Niño-like warming and interhemispheric differential warming. Moisture budget analysis further shows that the intensified precipitation arises from the relative influence of thermodynamic (moisture flux) and dynamic (wind) drivers across regions. These findings highlight the urgency of rapid policy implementation in vulnerable regions and can provide a scientific basis for developing regional adaptation strategies to mitigate growing extreme precipitation risks.
{"title":"Irreversibility of extreme precipitation intensity in global monsoon areas under multiple carbon neutrality scenarios","authors":"Md. Babul Miah , Jong-Yeon Park , Min-Uk Lee , Woojin Jeon , Young-Hwa Byun , Hyun Min Sung , Jin Gi Hong , Md. Jalal Uddin , Sanjit Kumar Mondal","doi":"10.1016/j.wace.2025.100843","DOIUrl":"10.1016/j.wace.2025.100843","url":null,"abstract":"<div><div>The Global Monsoon Areas (GMAs), home to over half of the world's population, face escalating socio-economic risks from extreme precipitation events intensified by rising atmospheric carbon dioxide (CO<sub>2</sub>). While previous studies have examined the irreversibility of the climate system following carbon neutrality, most have focused on single carbon neutrality scenarios with limited attention to these vulnerable areas. This study assesses the irreversibility of extreme precipitation intensity across seven GMA sub-regions under eight future scenarios, incorporating four carbon neutrality targets and two reduction rates, using simulations from a state-of-the-art climate model. Our results reveal that extreme precipitation intensity exhibits irreversible behavior in response to carbon neutrality forcing, failing to return to its initial level even when atmospheric CO<sub>2</sub> is reduced. This irreversibility is particularly pronounced when carbon neutrality timing is delayed, and the emission reduction rate is slow. Moreover, the irreversible response is nonlinear to the magnitude of carbon forcing, leading to distinct regional vulnerabilities, with some areas experiencing sharp increases in irreversibility by even small delays in reaching carbon neutrality. This region-specific behavior is largely attributed to increases in mean and variability of precipitation linked to irreversible El Niño-like warming and interhemispheric differential warming. Moisture budget analysis further shows that the intensified precipitation arises from the relative influence of thermodynamic (moisture flux) and dynamic (wind) drivers across regions. These findings highlight the urgency of rapid policy implementation in vulnerable regions and can provide a scientific basis for developing regional adaptation strategies to mitigate growing extreme precipitation risks.</div></div>","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"51 ","pages":"Article 100843"},"PeriodicalIF":6.9,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145689977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-04DOI: 10.1016/j.wace.2025.100842
Hannah R. Bourbon , Francine Machin , Pandora Hope , Brenda Mackie , Eric Lede
There is a proliferation of Extreme Event Attribution (EEA) science studies that quantify to what extent anthropogenic climate change influences extreme events. To date, no evidence explores how EEA may be used in decision-making contexts, across jurisdictions and governments, within Australia. Understanding this will allow targeted capability development, to ensure EEA supports effective climate risk decision-making. This study closes this knowledge gap and contributes to a novel understanding of EEA use and needs in a decision-making context within Australia, aligned with objectives: (1) Identifying decision-maker familiarity and use of EEA for extreme heat and rainfall events and (2) Understanding how decision-making needs for EEA vary across geographies, climates and jurisdictions. Forty-three diverse decision-makers were interviewed in Temperate South-Eastern and Tropical Northern regions of Australia, and at the federal level. Five key areas to improve EEA communication and increase uptake in decision-making contexts were identified under the categories: Language, Methodology, Impact Linkages, Action-Oriented Communication and Scientific Comprehension. Results demonstrate varied EEA needs across regions and scales, and reveal that despite high familiarity with EEA, it is not widely used for decision-making. Challenges preventing regional decision-maker use of EEA included few local level EEA studies, none available in Northern Australia and the need for improved EEA communication in this region. EEA is being used to increase climate risk understanding, but Action-Oriented Communication could allow EEA to also drive adaptation and mitigation decisions. Recognising and addressing the identified areas for improvement will strengthen EEA delivery to support diverse climate risk decision-making contexts.
{"title":"Understanding decision-maker needs for extreme event attribution science","authors":"Hannah R. Bourbon , Francine Machin , Pandora Hope , Brenda Mackie , Eric Lede","doi":"10.1016/j.wace.2025.100842","DOIUrl":"10.1016/j.wace.2025.100842","url":null,"abstract":"<div><div>There is a proliferation of Extreme Event Attribution (EEA) science studies that quantify to what extent anthropogenic climate change influences extreme events. To date, no evidence explores how EEA may be used in decision-making contexts, across jurisdictions and governments, within Australia. Understanding this will allow targeted capability development, to ensure EEA supports effective climate risk decision-making. This study closes this knowledge gap and contributes to a novel understanding of EEA use and needs in a decision-making context within Australia, aligned with objectives: (1) Identifying decision-maker familiarity and use of EEA for extreme heat and rainfall events and (2) Understanding how decision-making needs for EEA vary across geographies, climates and jurisdictions. Forty-three diverse decision-makers were interviewed in Temperate South-Eastern and Tropical Northern regions of Australia, and at the federal level. Five key areas to improve EEA communication and increase uptake in decision-making contexts were identified under the categories: Language, Methodology, Impact Linkages, Action-Oriented Communication and Scientific Comprehension. Results demonstrate varied EEA needs across regions and scales, and reveal that despite high familiarity with EEA, it is not widely used for decision-making. Challenges preventing regional decision-maker use of EEA included few local level EEA studies, none available in Northern Australia and the need for improved EEA communication in this region. EEA is being used to increase climate risk understanding, but Action-Oriented Communication could allow EEA to also drive adaptation and mitigation decisions. Recognising and addressing the identified areas for improvement will strengthen EEA delivery to support diverse climate risk decision-making contexts.</div></div>","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"51 ","pages":"Article 100842"},"PeriodicalIF":6.9,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145690053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.wace.2025.100838
Leibin Wang , Robert V. Rohli , Qigen Lin , Yanzhao Zhou , Siyan Dong , Shikai Song , Qiang Liu , Xiaodong Yan
Exposure to record-breaking heatwaves represents a significant and growing challenge for human health and societal well-being in a changing climate. Comprehending the risks of future exposure to record-breaking heatwaves is vital for devising effective mitigation strategies. However, population data, a key determinant in projecting future exposure risks, has rarely been scrutinized for the uncertainty it introduces into these projections. This study investigates population exposure risks to record-breaking heatwaves from 2020 to 2 100 using four population datasets (ECNU, Lund, NASA SEDAC, and Tsinghua) under various IPCC AR6 shared socioeconomic pathways (SSPs: 1–2.6, 2–4.5, 3–7.0, and 5–8.5). Results indicate that by the 2090s, approximately 0.9 billion, 2 billion, 4.8 billion, and 4 billion people per year will be exposed to record-breaking heatwaves under SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5, accounting for about 10 %, 21 %, 42 %, and 50 % of the total population, respectively. Key risk areas include East Asia, South Asia, Western and Central Europe, the Mediterranean coast, West and East Africa, and the Northeastern United States. Our results also demonstrate good consistency in global population estimates across the datasets under different SSPs, except for Lund, which tends to predict a higher global population than the other datasets by about 8 % in SSP2 and SSP3. The Kappa test results reveal that, in the context of global population distribution, while the datasets of ECNU and Tsinghua, as well as Lund and Tsinghua, display a strong degree of spatial consistency, other dataset combinations show only a moderate level of agreement. Notably, at the subcontinental level, significant disparities emerge in the projected population sizes and distributions across different population projections, and over time, this gap is widening. This will have a significant impact on the estimation of future population exposure. For example, in the Northern Hemisphere mid-to-high latitudes and the Australian region, the ECNU dataset forecasts a higher population growth rate than the other datasets. Subsequently, a similar trend is observed in the projections of population exposure to record-breaking heatwaves. These findings highlight the variability in regional risk projections across different population datasets, providing valuable insights for future population-related risk assessments and informing targeted mitigation efforts.
{"title":"Dissimilar global record-breaking heatwave exposure driven by divergent population projections within shared socioeconomic pathways","authors":"Leibin Wang , Robert V. Rohli , Qigen Lin , Yanzhao Zhou , Siyan Dong , Shikai Song , Qiang Liu , Xiaodong Yan","doi":"10.1016/j.wace.2025.100838","DOIUrl":"10.1016/j.wace.2025.100838","url":null,"abstract":"<div><div>Exposure to record-breaking heatwaves represents a significant and growing challenge for human health and societal well-being in a changing climate. Comprehending the risks of future exposure to record-breaking heatwaves is vital for devising effective mitigation strategies. However, population data, a key determinant in projecting future exposure risks, has rarely been scrutinized for the uncertainty it introduces into these projections. This study investigates population exposure risks to record-breaking heatwaves from 2020 to 2 100 using four population datasets (ECNU, Lund, NASA SEDAC, and Tsinghua) under various IPCC AR6 shared socioeconomic pathways (SSPs: 1–2.6, 2–4.5, 3–7.0, and 5–8.5). Results indicate that by the 2090s, approximately 0.9 billion, 2 billion, 4.8 billion, and 4 billion people per year will be exposed to record-breaking heatwaves under SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5, accounting for about 10 %, 21 %, 42 %, and 50 % of the total population, respectively. Key risk areas include East Asia, South Asia, Western and Central Europe, the Mediterranean coast, West and East Africa, and the Northeastern United States. Our results also demonstrate good consistency in global population estimates across the datasets under different SSPs, except for Lund, which tends to predict a higher global population than the other datasets by about 8 % in SSP2 and SSP3. The Kappa test results reveal that, in the context of global population distribution, while the datasets of ECNU and Tsinghua, as well as Lund and Tsinghua, display a strong degree of spatial consistency, other dataset combinations show only a moderate level of agreement. Notably, at the subcontinental level, significant disparities emerge in the projected population sizes and distributions across different population projections, and over time, this gap is widening. This will have a significant impact on the estimation of future population exposure. For example, in the Northern Hemisphere mid-to-high latitudes and the Australian region, the ECNU dataset forecasts a higher population growth rate than the other datasets. Subsequently, a similar trend is observed in the projections of population exposure to record-breaking heatwaves. These findings highlight the variability in regional risk projections across different population datasets, providing valuable insights for future population-related risk assessments and informing targeted mitigation efforts.</div></div>","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"50 ","pages":"Article 100838"},"PeriodicalIF":6.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145575309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.wace.2025.100790
Zihui Zhao , Shuiqing Yin , Jim Hall
As global warming intensifies, wet heatwaves pose an increasing threat to human health. As global climate models (GCMs) and their bias-corrected datasets are commonly used in wet heatwave research, it is essential to determine whether these datasets accurately represent wet heatwaves. We conducted a global assessment of 32 GCMs from CMIP6 and the NEX-GDDP-CMIP6, simulating wet heatwaves based on extended summer wet-bulb temperature (Tw) during 1981–2014, and compared them with the Global Meteorological Forcing Dataset (GMFD). Our findings indicate CMIP6 overestimates mean wet heatwave number (HWN), frequency (HWF), and duration (HWD), with relative biases from −32 % to 96 % (global mean: 10 %), −15 %–81 % (mean: 35 %), and −12 %–50 % (mean: 25 %) across IPCC climate reference regions, respectively. The exaggerated temporal autocorrelation of Tw, which statistically reflects an excessively persistent state of abnormal humid heat in GCMs, inflating biases in the count of events with long duration that probably lead to the overestimations of HWN, HWF, and HWD. CMIP6 significantly underestimates wet heatwave magnitude (HWM) by −70 %–6 % (mean: 9 %), primarily due to its underestimation of extreme Tw values. While the NEX-GDDP-CMIP6 dataset reduces this bias through the application of the quantile mapping method, it has limited effectiveness in correcting Tw autocorrelation, which restricts improvements in metrics such as HWN, HWF, and HWD. We find that heatwave intensity (HWI), reflecting the cumulative impact of heat, is influenced by the interplay between HWM and HWD. We identify the best-performing models for simulating wet heatwaves across continents using NEX-GDDP-CMIP6. These findings highlight the need for careful evaluation of both raw and bias-corrected datasets before using them in climate risk assessments.
随着全球变暖加剧，潮湿热浪对人类健康的威胁越来越大。由于全球气候模式（GCMs）及其偏差校正数据集通常用于湿性热浪研究，因此确定这些数据集是否准确地代表湿性热浪是至关重要的。基于1981-2014年夏季延长湿球温度（Tw），对CMIP6和NEX-GDDP-CMIP6的32个GCMs进行了全球评估，并与全球气象强迫数据集（GMFD）进行了比较。研究结果表明，CMIP6高估了IPCC气候参考区域的平均湿热浪数（HWN）、频率（HWF）和持续时间（HWD），相对偏差分别为- 32%至96%（全球平均值：10%）、- 15%至81%（平均值：35%）和- 12%至50%（平均值：25%）。Tw的夸张的时间自相关，在统计上反映了gcm中异常湿热的过度持续状态，膨胀了长时间事件计数的偏差，可能导致HWN、HWF和HWD的高估。CMIP6显著低估了湿热浪量级(HWM) - 70% - 6%（平均值：9%），主要是由于其低估了极端Tw值。虽然nex - gdp - cmip6数据集通过应用分位数映射方法减少了这种偏差，但它在纠正Tw自相关方面的有效性有限，这限制了HWN、HWF和HWD等指标的改进。研究发现，热浪强度（HWI）反映了热量的累积影响，并受到HWM和HWD相互作用的影响。我们确定了使用nex - gdp - cmip6模拟各大洲湿性热浪的最佳模型。这些发现突出表明，在将原始数据集和经过偏差校正的数据集用于气候风险评估之前，需要对它们进行仔细评估。
{"title":"Can wet heatwaves be represented by CMIP6 models and bias-corrected NEX-GDDP-CMIP6?","authors":"Zihui Zhao , Shuiqing Yin , Jim Hall","doi":"10.1016/j.wace.2025.100790","DOIUrl":"10.1016/j.wace.2025.100790","url":null,"abstract":"<div><div>As global warming intensifies, wet heatwaves pose an increasing threat to human health. As global climate models (GCMs) and their bias-corrected datasets are commonly used in wet heatwave research, it is essential to determine whether these datasets accurately represent wet heatwaves. We conducted a global assessment of 32 GCMs from CMIP6 and the NEX-GDDP-CMIP6, simulating wet heatwaves based on extended summer wet-bulb temperature (T<sub>w</sub>) during 1981–2014, and compared them with the Global Meteorological Forcing Dataset (GMFD). Our findings indicate CMIP6 overestimates mean wet heatwave number (HWN), frequency (HWF), and duration (HWD), with relative biases from −32 % to 96 % (global mean: 10 %), −15 %–81 % (mean: 35 %), and −12 %–50 % (mean: 25 %) across IPCC climate reference regions, respectively. The exaggerated temporal autocorrelation of T<sub>w</sub>, which statistically reflects an excessively persistent state of abnormal humid heat in GCMs, inflating biases in the count of events with long duration that probably lead to the overestimations of HWN, HWF, and HWD. CMIP6 significantly underestimates wet heatwave magnitude (HWM) by −70 %–6 % (mean: 9 %), primarily due to its underestimation of extreme T<sub>w</sub> values. While the NEX-GDDP-CMIP6 dataset reduces this bias through the application of the quantile mapping method, it has limited effectiveness in correcting T<sub>w</sub> autocorrelation, which restricts improvements in metrics such as HWN, HWF, and HWD. We find that heatwave intensity (HWI), reflecting the cumulative impact of heat, is influenced by the interplay between HWM and HWD. We identify the best-performing models for simulating wet heatwaves across continents using NEX-GDDP-CMIP6. These findings highlight the need for careful evaluation of both raw and bias-corrected datasets before using them in climate risk assessments.</div></div>","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"50 ","pages":"Article 100790"},"PeriodicalIF":6.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145684416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.wace.2025.100832
Murong Zhang , Xiao-Yi Yang , Yipeng Huang
Weak stratospheric polar vortex (WSPV) events are dynamically connected with the variations in the tropospheric circulation, serving as crucial harbingers for surface cold extremes in the Northern Hemisphere. Although WSPV events are usually featured with either displaced or split stratospheric polar vortex pattern, a notable portion of WSPV events experiences both patterns successively, leading to inconclusive surface impacts of different WSPV events. Here, we propose a novel method to quantitatively identify WSPV events with vortex transition (namely, mixed-type WSPV events) by performing clustering analysis on WSPV days based on 42-yr ERA5 reanalysis, and further examine their climatological features, surface impacts and tropospheric precursors. Results show that the mixed-type WSPV events are usually featured with a routine vortex evolution from displacement to split. In contrast to comparatively weak tropospheric response to pure displaced- and split-type events, the mixed-type WSPV events feature the longer persistence of stratospheric circulation anomalies and are followed by stronger negative Arctic Oscillation-like surface signatures, further contributing to more robust cold anomalies over northern Eurasia and the central U.S. 10–39 days after event onset. Moreover, mixed-type events are typically induced by upward propagated wave activity flux into the stratosphere contributed by the synergistic enhancement of tropospheric planetary wavenumbers 1 and 2. The enhancement of tropospheric planetary wavenumbers 1 and 2 is associated with deepening of the Aleutian Low and strengthening of the dipole over northern Scandinavia-eastern Siberia, respectively. This tropospheric configuration can sevrve as a vital precursor pattern for mixed-type WSPV events, hinting at extreme cold events with far-reaching societal impacts.
{"title":"A strong stratospheric harbinger for cold extremes: Weak polar vortex transition from displacement to split pattern","authors":"Murong Zhang , Xiao-Yi Yang , Yipeng Huang","doi":"10.1016/j.wace.2025.100832","DOIUrl":"10.1016/j.wace.2025.100832","url":null,"abstract":"<div><div>Weak stratospheric polar vortex (WSPV) events are dynamically connected with the variations in the tropospheric circulation, serving as crucial harbingers for surface cold extremes in the Northern Hemisphere. Although WSPV events are usually featured with either displaced or split stratospheric polar vortex pattern, a notable portion of WSPV events experiences both patterns successively, leading to inconclusive surface impacts of different WSPV events. Here, we propose a novel method to quantitatively identify WSPV events with vortex transition (namely, mixed-type WSPV events) by performing clustering analysis on WSPV days based on 42-yr ERA5 reanalysis, and further examine their climatological features, surface impacts and tropospheric precursors. Results show that the mixed-type WSPV events are usually featured with a routine vortex evolution from displacement to split. In contrast to comparatively weak tropospheric response to pure displaced- and split-type events, the mixed-type WSPV events feature the longer persistence of stratospheric circulation anomalies and are followed by stronger negative Arctic Oscillation-like surface signatures, further contributing to more robust cold anomalies over northern Eurasia and the central U.S. 10–39 days after event onset. Moreover, mixed-type events are typically induced by upward propagated wave activity flux into the stratosphere contributed by the synergistic enhancement of tropospheric planetary wavenumbers 1 and 2. The enhancement of tropospheric planetary wavenumbers 1 and 2 is associated with deepening of the Aleutian Low and strengthening of the dipole over northern Scandinavia-eastern Siberia, respectively. This tropospheric configuration can sevrve as a vital precursor pattern for mixed-type WSPV events, hinting at extreme cold events with far-reaching societal impacts.</div></div>","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"50 ","pages":"Article 100832"},"PeriodicalIF":6.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145531897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.wace.2025.100834
Y.X. Liu , Y. Zhang , H.P. Hong
Tornadoes can potentially damage structures and cause fatalities. Although tornado occurrence is often observed in China's mainland, a systematic development of a comprehensive catalogue that forms the basis for tornado hazard assessment and mapping was not available. In the present study, a tornado catalogue from 1949 to 2023 over China's mainland was compiled based on extensive literature research. This catalogue was used as the basis to map the spatially varying tornado occurrence rate and to develop a stochastic tornado occurrence model. For the mapping of the spatially varying tornado occurrence, the adaptive Gaussian kernel smoothing and the adaptive diffusion smoothing were employed. The newly developed stochastic occurrence model together with an adopted practical tornado wind field model were used to map the tornado hazards over China's mainland in terms of the annual maximum tornado wind speed for given exceedance probabilities. The hazard was assessed for a site represented by a point as well as for a circular area, showing that the hazard is not negligible, and the hazard increases drastically as the size of the circular area increases. This implied that tornado hazard can be significant for a portfolio of structures within a relatively large circular area. The mapped hazard indicated that the hazard is not negligible for nuclear structures by considering the annual exceedance probability of 10−7, which is stipulated in the design code. The estimated tornado wind hazard was compared with that estimated based on a code-suggested procedure, which was developed and implemented in the 1970s and 1980s. The comparison indicated that the code procedure, in general, leads to a much greater tornado wind speed hazard. Some of the assumptions that resulted in the overestimation were identified. In addition, two new sets of empirical equations for the tornado path length, width and area were developed. The first set can be used for tornadoes with the F-scale rating and the second set for tornadoes with the EF-scale rating.
{"title":"Estimating tornado occurrence and tornado wind hazard in China","authors":"Y.X. Liu , Y. Zhang , H.P. Hong","doi":"10.1016/j.wace.2025.100834","DOIUrl":"10.1016/j.wace.2025.100834","url":null,"abstract":"<div><div>Tornadoes can potentially damage structures and cause fatalities. Although tornado occurrence is often observed in China's mainland, a systematic development of a comprehensive catalogue that forms the basis for tornado hazard assessment and mapping was not available. In the present study, a tornado catalogue from 1949 to 2023 over China's mainland was compiled based on extensive literature research. This catalogue was used as the basis to map the spatially varying tornado occurrence rate and to develop a stochastic tornado occurrence model. For the mapping of the spatially varying tornado occurrence, the adaptive Gaussian kernel smoothing and the adaptive diffusion smoothing were employed. The newly developed stochastic occurrence model together with an adopted practical tornado wind field model were used to map the tornado hazards over China's mainland in terms of the annual maximum tornado wind speed for given exceedance probabilities. The hazard was assessed for a site represented by a point as well as for a circular area, showing that the hazard is not negligible, and the hazard increases drastically as the size of the circular area increases. This implied that tornado hazard can be significant for a portfolio of structures within a relatively large circular area. The mapped hazard indicated that the hazard is not negligible for nuclear structures by considering the annual exceedance probability of 10<sup>−7</sup>, which is stipulated in the design code. The estimated tornado wind hazard was compared with that estimated based on a code-suggested procedure, which was developed and implemented in the 1970s and 1980s. The comparison indicated that the code procedure, in general, leads to a much greater tornado wind speed hazard. Some of the assumptions that resulted in the overestimation were identified. In addition, two new sets of empirical equations for the tornado path length, width and area were developed. The first set can be used for tornadoes with the F-scale rating and the second set for tornadoes with the EF-scale rating.</div></div>","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"50 ","pages":"Article 100834"},"PeriodicalIF":6.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145553544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.wace.2025.100837
Yue Li , Yang Yang , Leying Zhang , Jiuwei Zhao , Kun Wu , Shanshan Liu
The impact of tropical volcanic eruptions (TVEs) on tropical cyclone (TC) activity remains a subject of ongoing debate. Here, we investigate the effects of the 1815 Tambora eruption, which occurred during the pre-industrial period, with that of the 1991 Pinatubo eruption in present-day era on TC activity in the western North Pacific (WNP). Using high-resolution simulations and proxy data derived from reanalyses, we find that both TVEs lead to significant increases in TC genesis frequency (TCGF) and track density (TCTD) over the WNP. The Tambora eruption triggers the equatorial central Pacific warming, inducing tropical westerly wind anomalies in the WNP. While thermodynamic conditions were generally unfavorable for TC genesis, the dominant influence of dynamic factors facilitated increased TC activity. Our findings suggest that the cooling effect of TVEs can be viewed as a transient analog of global warming, providing valuable insights into future TC variability under changing climatic conditions.
{"title":"Possible increase of tropical cyclone genesis frequency over the Northwest Pacific induced by the Tambora eruption in 1815","authors":"Yue Li , Yang Yang , Leying Zhang , Jiuwei Zhao , Kun Wu , Shanshan Liu","doi":"10.1016/j.wace.2025.100837","DOIUrl":"10.1016/j.wace.2025.100837","url":null,"abstract":"<div><div>The impact of tropical volcanic eruptions (TVEs) on tropical cyclone (TC) activity remains a subject of ongoing debate. Here, we investigate the effects of the 1815 Tambora eruption, which occurred during the pre-industrial period, with that of the 1991 Pinatubo eruption in present-day era on TC activity in the western North Pacific (WNP). Using high-resolution simulations and proxy data derived from reanalyses, we find that both TVEs lead to significant increases in TC genesis frequency (TCGF) and track density (TCTD) over the WNP. The Tambora eruption triggers the equatorial central Pacific warming, inducing tropical westerly wind anomalies in the WNP. While thermodynamic conditions were generally unfavorable for TC genesis, the dominant influence of dynamic factors facilitated increased TC activity. Our findings suggest that the cooling effect of TVEs can be viewed as a transient analog of global warming, providing valuable insights into future TC variability under changing climatic conditions.</div></div>","PeriodicalId":48630,"journal":{"name":"Weather and Climate Extremes","volume":"50 ","pages":"Article 100837"},"PeriodicalIF":6.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145560160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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