Pub Date : 2025-09-01Epub Date: 2025-05-20DOI: 10.1016/j.aosl.2025.100647
Haosu Tang , Gang Huang , Kaiming Hu , Jun Wang , Cunrui Huang , Xianke Yang
Against the backdrop of global warming, China has been facing increasingly frequent and severe extreme weather and climate events, with a prominent risk of compound extreme events induced by interactions among multiple climate drivers and/or hazards. The present study first reviews the definition and classification of compound extreme events in China. Then, it summarizes research progress on the evolutionary characteristics, formation mechanisms, and future projections of different types of compound extreme events. The potential risks and possible impact pathways of three specific event types—namely, continuous day–night hot extremes, temperature–humidity compound events, and high-temperature–ozone compound events—on the health of the Chinese population are then explored. Finally, a framework for assessing the hazard risk of compound extreme events is constructed, accompanied by response strategies based on carbon neutrality targets. Building on existing research achievements, five future research directions are proposed: (1) identifying the risk chains of compound events; (2) addressing the constraints of observational records and coupled model performances; (3) attributing and understanding the drivers of compound extreme events; (4) finding optimal pathways for carbon reduction and air quality improvement; and (5) promoting inter-disciplinary, multi-regional, and cross-sectoral collaboration. Strengthening research in these directions will deepen our understanding of compound extreme events and provide technological support for climate change adaptation and health risk responses in China.
{"title":"Compound extreme events and health risks in China: A review","authors":"Haosu Tang , Gang Huang , Kaiming Hu , Jun Wang , Cunrui Huang , Xianke Yang","doi":"10.1016/j.aosl.2025.100647","DOIUrl":"10.1016/j.aosl.2025.100647","url":null,"abstract":"<div><div>Against the backdrop of global warming, China has been facing increasingly frequent and severe extreme weather and climate events, with a prominent risk of compound extreme events induced by interactions among multiple climate drivers and/or hazards. The present study first reviews the definition and classification of compound extreme events in China. Then, it summarizes research progress on the evolutionary characteristics, formation mechanisms, and future projections of different types of compound extreme events. The potential risks and possible impact pathways of three specific event types—namely, continuous day–night hot extremes, temperature–humidity compound events, and high-temperature–ozone compound events—on the health of the Chinese population are then explored. Finally, a framework for assessing the hazard risk of compound extreme events is constructed, accompanied by response strategies based on carbon neutrality targets. Building on existing research achievements, five future research directions are proposed: (1) identifying the risk chains of compound events; (2) addressing the constraints of observational records and coupled model performances; (3) attributing and understanding the drivers of compound extreme events; (4) finding optimal pathways for carbon reduction and air quality improvement; and (5) promoting inter-disciplinary, multi-regional, and cross-sectoral collaboration. Strengthening research in these directions will deepen our understanding of compound extreme events and provide technological support for climate change adaptation and health risk responses in China.</div><div>摘要</div><div>在全球变暖的背景下, 中国面临着日益频繁和严峻的极端天气气候事件, 其中以多种气候驱动因子和/或灾害相互作用而形成的复合型极端事件风险尤为突出. 本文首先回顾了中国区域复合型极端事件的定义与分型; 然后综述了不同类型复合型极端事件的演变特征, 形成机制以及未来预估等方面的研究进展; 随后, 探讨了日夜持续型极端高温事件, 温湿复合事件以及高温–臭氧复合事件等三类事件对我国人群健康的潜在风险及可能的影响途径; 最后, 阐述了复合型极端事件灾害风险评估框架, 并在此基础上提出了基于碳中和目标的应对策略. 在总结既有研究成果的基础上, 提出了五个未来亟需关注的研究方向: (1)复合事件灾害风险链的识别问题; (2)观测资料和耦合模式性能的制约问题; (3)复合型极端事件的归因与成因问题; (4)碳减排与空气质量改善的最优路径问题; (5)多学科, 多区域, 多部门的合作问题. 加强上述方向的研究有助于深化对复合型极端事件的理解, 并为我国气候变化适应和健康风险应对提供科技支撑.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 5","pages":"Article 100647"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-09-01Epub Date: 2025-05-02DOI: 10.1016/j.aosl.2025.100637
Dong Gao , Wenkang Gao , Zhanyun Ma , Lingyun Zhu , Jiajing Tian , Shule Liu , Yangchun Yu , Guozhong Zhang , Qingxian Gao
The trends and characteristics of global CH4 emissions were analyzed using greenhouse gas data reported by both Annex I and non-Annex I countries under the United Nations Framework Convention on Climate Change (UNFCCC) from 1990 to 2021. The results show the following: (1) In 2021, the cumulative CH4 emissions from the 42 nations listed in Annex I of the UNFCCC amounted to 1871521.79 kt CO2 eq. The top 10 countries account for 82.0 % of the total CH4 emissions. (2) Most Annex I countries showed a gradual decline in CH4 emissions over the period. In contrast, emissions from non-Annex I countries have increased year by year. Notably, CH4 emissions in the United States, the European Union, the Russian Federation, and Ukraine decreased by 14.0 %, 37.4 %, 24.0 %, and 60.9 %, respectively. (3) In 2020, the CH4 emissions of the agriculture, energy, waste treatment and LULUCF (land use, land-use change and forestry) sectors in Annex I countries were 72240.43, 63863.51, 41573.08, and 889019 million tons of CO2 eq, accounting for 38.6 %, 34.1 %, 22.2 %, and 4.8 %, respectively. Among non-Annex I countries, the main CH4 sources vary by country. In China and Mexico, energy and agriculture were the largest contributors, accounting for 44.8 % and 40.2 % in China, and 34.4 % and 43.3 % in Mexico, respectively. In India, Brazil, Nigeria, Argentina, and Vietnam, agriculture dominated, contributing 73.8 %, 75.8 %, 59.7 %, 60.3 %, and 58.5 % of total emissions, respectively. Indonesia was an exception, with waste treatment being the primary source, accounting for 64.8 % of its total CH4 emissions.
{"title":"Trends and characteristics of global CH4 emissions: Insights from UNFCCC greenhouse gas inventories","authors":"Dong Gao , Wenkang Gao , Zhanyun Ma , Lingyun Zhu , Jiajing Tian , Shule Liu , Yangchun Yu , Guozhong Zhang , Qingxian Gao","doi":"10.1016/j.aosl.2025.100637","DOIUrl":"10.1016/j.aosl.2025.100637","url":null,"abstract":"<div><div>The trends and characteristics of global CH<sub>4</sub> emissions were analyzed using greenhouse gas data reported by both Annex I and non-Annex I countries under the United Nations Framework Convention on Climate Change (UNFCCC) from 1990 to 2021. The results show the following: (1) In 2021, the cumulative CH<sub>4</sub> emissions from the 42 nations listed in Annex I of the UNFCCC amounted to 1871521.79 kt CO<sub>2</sub> eq. The top 10 countries account for 82.0 % of the total CH<sub>4</sub> emissions. (2) Most Annex I countries showed a gradual decline in CH<sub>4</sub> emissions over the period. In contrast, emissions from non-Annex I countries have increased year by year. Notably, CH<sub>4</sub> emissions in the United States, the European Union, the Russian Federation, and Ukraine decreased by 14.0 %, 37.4 %, 24.0 %, and 60.9 %, respectively. (3) In 2020, the CH<sub>4</sub> emissions of the agriculture, energy, waste treatment and LULUCF (land use, land-use change and forestry) sectors in Annex I countries were 72240.43, 63863.51, 41573.08, and 889019 million tons of CO<sub>2</sub> eq, accounting for 38.6 %, 34.1 %, 22.2 %, and 4.8 %, respectively. Among non-Annex I countries, the main CH<sub>4</sub> sources vary by country. In China and Mexico, energy and agriculture were the largest contributors, accounting for 44.8 % and 40.2 % in China, and 34.4 % and 43.3 % in Mexico, respectively. In India, Brazil, Nigeria, Argentina, and Vietnam, agriculture dominated, contributing 73.8 %, 75.8 %, 59.7 %, 60.3 %, and 58.5 % of total emissions, respectively. Indonesia was an exception, with waste treatment being the primary source, accounting for 64.8 % of its total CH<sub>4</sub> emissions.</div><div>摘要</div><div>基于《联合国气候变化框架公约》 (UNFCCC) 附件一国家提交的 1990 年至最新清单年份 (2021 年) 温室气体排放数据, 探讨了附件一和非附件一国家排放现状, 演变趋势和关键排放源. 结果表明: 2021年UNFCCC附件一中42个国家CH<sub>4</sub>总排放量为1871521.79 kt CO<sub>2</sub>当量. 排在前10位的国家占CH<sub>4</sub>总排放量的82.0 %. (2)大多数附件一国家的CH<sub>4</sub>排放量呈逐渐下降趋势, 非附件一国家的CH<sub>4</sub>排放量呈逐年增加趋势, 其中最大的排放源的美国, 欧盟(公约), 俄罗斯联邦和乌克兰排放量分别下降了13.96 %, 37.44 %, 24.01 %和60.89 %. 乌克兰, 英国, 意大利和罗马尼亚与1990年相比, 2021年的排放量减少了60 %以上. (3) 2020年, 附件一国家农业, 能源, 废物处理和LULUCF行业的CH<sub>4</sub>排放量分别为72240.43, 63863.51, 41573.08和889.19亿吨CO<sub>2</sub>当量, 占比分别为38.60 %, 34.11 %, 22.21 %和4.75 %. 在UNFCCC非附件一国家中, 能源和农业部门是中国和墨西哥最主要的CH<sub>4</sub>排放源, 分别占中国总排放量的44.77 %和40.23 %, 占墨西哥总排放量的34.44 %和43.29 %. 在印度, 巴西, 尼日利亚, 阿根廷和越南, 农业部门是最主要的排放源, 分别占总排放量的73.75 %, 75.78 %, 59.66 %, 60.29 %和58.47 %. 印度尼西亚以废物处理部门为主, 占总排放量的64.79 %.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 5","pages":"Article 100637"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-09-01Epub Date: 2024-11-14DOI: 10.1016/j.aosl.2024.100572
Ryohei Misumi , Akihiro Hashimoto
A double-moment cloud microphysics scheme requires an assumption for cloud droplet size distributions (DSDs). However, since observations of cloud DSDs are limited, default values for shape parameters and cloud condensation nuclei activation parameters are often used in numerical simulations. In this study, the effects of cloud DSDs on numerical simulations of warm stratiform precipitation around Tokyo are investigated using the Japan Meteorological Agency's non-hydrostatic model, which incorporates a double-moment cloud microphysics scheme. Simulations using the default cloud DSD showed higher cloud droplet number concentrations and lower radar reflectivity than observed data, suggesting that the default cloud DSD is too narrow. Simulations with a cloud DSD based on in situ cloud observations corrected these errors. In addition, observation-based cloud DSDs affected rainfall amounts through the autoconversion rate of cloud water and improved the threat scores. These results suggest that realistic cloud DSDs should be provided for double-moment cloud microphysics schemes in scientific studies.
{"title":"Impacts of observation-based cloud droplet size distributions on the simulation of warm stratiform precipitation using a double-moment microphysics scheme","authors":"Ryohei Misumi , Akihiro Hashimoto","doi":"10.1016/j.aosl.2024.100572","DOIUrl":"10.1016/j.aosl.2024.100572","url":null,"abstract":"<div><div>A double-moment cloud microphysics scheme requires an assumption for cloud droplet size distributions (DSDs). However, since observations of cloud DSDs are limited, default values for shape parameters and cloud condensation nuclei activation parameters are often used in numerical simulations. In this study, the effects of cloud DSDs on numerical simulations of warm stratiform precipitation around Tokyo are investigated using the Japan Meteorological Agency's non-hydrostatic model, which incorporates a double-moment cloud microphysics scheme. Simulations using the default cloud DSD showed higher cloud droplet number concentrations and lower radar reflectivity than observed data, suggesting that the default cloud DSD is too narrow. Simulations with a cloud DSD based on in situ cloud observations corrected these errors. In addition, observation-based cloud DSDs affected rainfall amounts through the autoconversion rate of cloud water and improved the threat scores. These results suggest that realistic cloud DSDs should be provided for double-moment cloud microphysics schemes in scientific studies.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 5","pages":"Article 100572"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-09-01Epub Date: 2024-12-16DOI: 10.1016/j.aosl.2024.100587
Siyuan Li , Kai Wang , Hao Miao , Xuedan Zhu , Yanjie Liu , Jinxiao Li , Wei Wang , Xiao Zheng , Juan Feng , Xiaocong Wang
Surface wind speed (SWS) not only plays a crucial role in regulating the Earth's energy and hydrological cycle, but also is an important source of sustainable renewable energy. This study assesses the credibility of SWSs in three reanalyses (ERA5, MERRA2, and JRA-55) in East Asia using both satellite and in-situ observations. Results show all three reanalyses can capture the spatial pattern of SWS as in observations, yet there are notable differences in magnitude. On land, ERA5 and MERRA2 overestimate the SWS by about 0.6 and 1.5 m s−1, respectively, whereas JRA-55 underestimates it. The biases over the oceans are opposite to those on land and are relatively small due to the assimilation of observations of oceanic surface winds. Overall, JRA-55 and ERA5 offer better estimates of seasonal means and variances of SWS than MERRA2. The observed SWS shows a negative trend of −0.08 m s−1/10 yr on land and a positive trend of 0.09 m s−1/10 yr in the western North Pacific. Only JRA-55 shows similar trends to observations over both land and ocean, while ERA5 and MERRA2 show varying degrees of deviation from the observations. Further investigation shows that there is a strong link between the trend of SWS and that of the large-scale circulation, and that a large part of the SWS trend can be attributed to changes in large-scale circulations.
地表风速不仅在调节地球能量和水文循环中起着至关重要的作用，而且是可持续可再生能源的重要来源。本研究利用卫星和原位观测，评估了东亚地区三个再分析（ERA5、MERRA2和JRA-55）中SWSs的可信度。结果表明，三种再分析方法均能较好地捕捉到SWS的空间格局，但在量级上存在显著差异。在陆地上，ERA5和MERRA2分别高估了约0.6和1.5 m s - 1的SWS，而JRA-55则低估了它。海洋上的偏差与陆地上的相反，由于同化了海洋表面风的观测，因此偏差相对较小。总体而言，JRA-55和ERA5提供了比MERRA2更好的季节平均和SWS方差估计。观测到的SWS在陆地呈负趋势（- 0.08 m s−1/10 yr），在北太平洋西部呈正趋势（0.09 m s−1/10 yr）。只有JRA-55显示出与陆地和海洋观测结果相似的趋势，而ERA5和MERRA2显示出不同程度的偏差。进一步的研究表明，SWS趋势与大尺度环流趋势之间存在着很强的联系，SWS趋势的很大一部分可归因于大尺度环流的变化。（sws） http://www.chinac.cn/cn/或http://www.chinac.cn/cn/。这是一个很好的例子。具体而言,在陆地区域,ERA5和MERRA2分别高估了约0.6−1和1.5年代−1,而JRA-55则存在低估现象;而在海洋区域, 偏差情况与陆地相反. 【中文翻译】：http://www.georg.cn/cn/】【中文译文】
{"title":"Evaluation of surface wind speed over East Asia and the adjacent ocean in three reanalyses using satellite and in-situ observations","authors":"Siyuan Li , Kai Wang , Hao Miao , Xuedan Zhu , Yanjie Liu , Jinxiao Li , Wei Wang , Xiao Zheng , Juan Feng , Xiaocong Wang","doi":"10.1016/j.aosl.2024.100587","DOIUrl":"10.1016/j.aosl.2024.100587","url":null,"abstract":"<div><div>Surface wind speed (SWS) not only plays a crucial role in regulating the Earth's energy and hydrological cycle, but also is an important source of sustainable renewable energy. This study assesses the credibility of SWSs in three reanalyses (ERA5, MERRA2, and JRA-55) in East Asia using both satellite and in-situ observations. Results show all three reanalyses can capture the spatial pattern of SWS as in observations, yet there are notable differences in magnitude. On land, ERA5 and MERRA2 overestimate the SWS by about 0.6 and 1.5 m s<sup>−1</sup>, respectively, whereas JRA-55 underestimates it. The biases over the oceans are opposite to those on land and are relatively small due to the assimilation of observations of oceanic surface winds. Overall, JRA-55 and ERA5 offer better estimates of seasonal means and variances of SWS than MERRA2. The observed SWS shows a negative trend of −0.08 m s<sup>−1</sup>/10 yr on land and a positive trend of 0.09 m s<sup>−1</sup>/10 yr in the western North Pacific. Only JRA-55 shows similar trends to observations over both land and ocean, while ERA5 and MERRA2 show varying degrees of deviation from the observations. Further investigation shows that there is a strong link between the trend of SWS and that of the large-scale circulation, and that a large part of the SWS trend can be attributed to changes in large-scale circulations.</div><div>摘要</div><div>利用卫星和地面站点观测数据, 本文对再分析产品中的地表风速 (SWS) 进行了可信度评估. 研究结果表明, 再分析产品能够较好地再现SWS的观测分布特征, 但在风速的量级上则存在显著差异. 具体而言, 在陆地区域, ERA5和MERRA2分别高估了约0.6 m s<sup>−1</sup>和1.5 m s<sup>−1</sup>, 而JRA-55则存在低估现象; 而在海洋区域, 偏差情况与陆地相反. 总体来看, JRA-55和ERA5在模拟SWS的气候态及其变率方面, 更加接近观测数据. 其中, JRA-55中SWS的年代际趋势与观测数据最为一致.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 5","pages":"Article 100587"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-09-01Epub Date: 2024-12-03DOI: 10.1016/j.aosl.2024.100584
Tianliang Gao , Yue Sui , Bo Liu , Yuxuan Peng , Wenxuan Qiao
Deforestation has a significant influence on the hydrological cycle. Understanding the impact of deforestation on precipitation extremes is crucial for addressing global environmental challenges. This study investigates the impact of deforestation on precipitation extremes (R95p index, which represents the total amount of precipitation exceeding the 95th percentile of the reference period) in China, using outputs from three earth system models (CanESM5, IPSL-CM6A-LR, and MIROC-ES2L). All models, along with their multimodel mean, indicate a general decrease in R95p in Northeast China and southern China, and changes in Northwest China and the Tibetan Plateau are minimal. In contrast, the responses are model-dependent in the Huanghuai and Jianghuai regions. The overall nationwide multimodel mean suggests an annual R95p decrease of 10.7 mm, with individual model variations ranging from −28.0 to 2.0 mm. Further analysis using precipitation extremes scaling reveals a high spatial correlation with direct precipitation extremes changes on both annual and seasonal scales, albeit with slightly smaller magnitudes. Decomposing the response into dynamic and thermodynamic scaling, the authors find that dynamic contributions predominantly drive the changes in precipitation extremes on both annual and seasonal scales. The authors findings highlight the substantial role of dynamic processes in modulating the response of precipitation extremes to deforestation in China.
{"title":"Impact of deforestation on precipitation extremes in China based on land use model intercomparison project models","authors":"Tianliang Gao , Yue Sui , Bo Liu , Yuxuan Peng , Wenxuan Qiao","doi":"10.1016/j.aosl.2024.100584","DOIUrl":"10.1016/j.aosl.2024.100584","url":null,"abstract":"<div><div>Deforestation has a significant influence on the hydrological cycle. Understanding the impact of deforestation on precipitation extremes is crucial for addressing global environmental challenges. This study investigates the impact of deforestation on precipitation extremes (R95p index, which represents the total amount of precipitation exceeding the 95th percentile of the reference period) in China, using outputs from three earth system models (CanESM5, IPSL-CM6A-LR, and MIROC-ES2L). All models, along with their multimodel mean, indicate a general decrease in R95p in Northeast China and southern China, and changes in Northwest China and the Tibetan Plateau are minimal. In contrast, the responses are model-dependent in the Huanghuai and Jianghuai regions. The overall nationwide multimodel mean suggests an annual R95p decrease of 10.7 mm, with individual model variations ranging from −28.0 to 2.0 mm. Further analysis using precipitation extremes scaling reveals a high spatial correlation with direct precipitation extremes changes on both annual and seasonal scales, albeit with slightly smaller magnitudes. Decomposing the response into dynamic and thermodynamic scaling, the authors find that dynamic contributions predominantly drive the changes in precipitation extremes on both annual and seasonal scales. The authors findings highlight the substantial role of dynamic processes in modulating the response of precipitation extremes to deforestation in China.</div><div>摘要</div><div>森林砍伐对水循环影响显著, 理解森林砍伐对极端降水的影响对于应对全球环境挑战至关重要.基 于CanESM5, IPSL-CM6A-LR和MIROC-ES2L三个地球系统模式, 本文探讨了森林砍伐对中国极端降水 (R95p指数, 即超过参考期第95百分位降水量总和) 的影响. 所有模式及其集合平均表明, 森林砍伐后我国东北和南方R95p普遍减少; 西北和青藏高原的变化较小; 而黄淮和江淮地区的响应则依赖于模式. 进一步, 在年和季节尺度上, 极端降水物理尺度诊断方法得到的极端降水响应与上述响应具有高空间相似性, 且动力作用主导了森林砍伐对极端降水的影响.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 5","pages":"Article 100584"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-09-01Epub Date: 2025-05-20DOI: 10.1016/j.aosl.2025.100648
Zhiheng Chen, Zhihai Zheng
Since the 21st century, the Huang–Huai–Hai River Basin (HHHRB) in China has experienced increased frequency and severity of drought–flood abrupt alternation (DFAA) events during early summer, characterized by droughts in June followed by floods in July. The 2024 event was the most severe since 1981. This study demonstrates that such compound extreme events are closely linked to anomalous subseasonal evolution of large-scale atmospheric circulation. During the drought phase, the East Asian subtropical westerly jet (EAJ) shifts southward, and the western Pacific subtropical high (WPSH) exhibits anomalous strengthening with its western ridge line displaced southward. The flood phase is characterized by acceleration of the EAJ, westward extension of the WPSH, and enhanced southwestern moisture transport from the western Pacific. Beyond these typical features, the 2024 early summer circulation exhibited unique characteristics: Anomalous northeastward intensification of the WPSH facilitated merged moisture influx from both the Indian Ocean and the western Pacific along the southeast pathway into the HHHRB in July, resulting in the highest net moisture inflow at the southern boundary of the HHHRB since 1981. The synergistic effects of multiple factors primarily explain the exceptionally intense DFAA event in 2024.
{"title":"The strongest early-summer drought–flood abrupt alternation event over the Huang–Huai–Hai River Basin in 2024 since the 1980s: Perspective of anomalous subseasonal circulation evolution","authors":"Zhiheng Chen, Zhihai Zheng","doi":"10.1016/j.aosl.2025.100648","DOIUrl":"10.1016/j.aosl.2025.100648","url":null,"abstract":"<div><div>Since the 21st century, the Huang–Huai–Hai River Basin (HHHRB) in China has experienced increased frequency and severity of drought–flood abrupt alternation (DFAA) events during early summer, characterized by droughts in June followed by floods in July. The 2024 event was the most severe since 1981. This study demonstrates that such compound extreme events are closely linked to anomalous subseasonal evolution of large-scale atmospheric circulation. During the drought phase, the East Asian subtropical westerly jet (EAJ) shifts southward, and the western Pacific subtropical high (WPSH) exhibits anomalous strengthening with its western ridge line displaced southward. The flood phase is characterized by acceleration of the EAJ, westward extension of the WPSH, and enhanced southwestern moisture transport from the western Pacific. Beyond these typical features, the 2024 early summer circulation exhibited unique characteristics: Anomalous northeastward intensification of the WPSH facilitated merged moisture influx from both the Indian Ocean and the western Pacific along the southeast pathway into the HHHRB in July, resulting in the highest net moisture inflow at the southern boundary of the HHHRB since 1981. The synergistic effects of multiple factors primarily explain the exceptionally intense DFAA event in 2024.</div><div>摘要</div><div>21世纪以来, 中国黄淮海地区初夏旱涝急转事件 (6月旱–7月涝) 呈频次增多, 强度增强趋势, 2024年事件为1981年以来最强. 研究表明, 此类复合极端事件与大尺度环流的季节内异常演变密切相关, 其中旱期表现为东亚副热带西风急流的位置偏南, 西太副高的强度偏强但西段脊线偏南; 涝期表现为东亚副热带西风急流增速, 西太副高西伸脊点偏西与西南路径西太水汽的增多. 除上述典型特征外, 2024年初夏的环流演变兼具特殊性——初夏西太副高向东北方向的异常加强, 导致7月印度洋水汽和东南路径的西太水汽合并汇入黄淮海地区, 造成其南边界水汽净流入量达1981年以来峰值. 以上多要素协同是2024年黄淮海地区旱涝急转事件强度异常偏强的重要原因.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 5","pages":"Article 100648"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The year 2024 witnessed remarkable climatic anomalies across China, characterized by pronounced warm and wet conditions. The annual mean temperature soared to a record high since 1951, with seasonal temperatures in spring, summer, and autumn all exceeding historical extremes. Meanwhile, the annual precipitation ranked as the fourth highest on record, with all four seasons experiencing above-average rainfall. Notably, the Yangtze River Basin and Jiangnan region encountered their most intense precipitation event since 1961. Extreme weather events were particularly striking: An unusually early and severe heatwave swept through central and eastern China, becoming the second most intense high-temperature event in recorded history. Autumn typhoon activity also displayed exceptional intensity, with Typhoon Yagi triggering significant impacts in Hainan, Guangdong, and Guangxi. Although drought conditions were generally mild overall, notable seasonal and regional disparities emerged, especially in the winter–spring droughts affecting southwestern China. Conversely, cold outbreaks occurred more frequently than usual, and convective weather events exhibited heightened activity. Moreover, dust storm activity remained relatively limited.
{"title":"State of China’s climate in 2024","authors":"Yundi Jiang, Lin Zhao, Xiucang Li, Xianyan Chen, Xukai Zou, Yiran Wang, Hongling Zeng, Tong Cui, Hailing Zhong","doi":"10.1016/j.aosl.2025.100661","DOIUrl":"10.1016/j.aosl.2025.100661","url":null,"abstract":"<div><div>The year 2024 witnessed remarkable climatic anomalies across China, characterized by pronounced warm and wet conditions. The annual mean temperature soared to a record high since 1951, with seasonal temperatures in spring, summer, and autumn all exceeding historical extremes. Meanwhile, the annual precipitation ranked as the fourth highest on record, with all four seasons experiencing above-average rainfall. Notably, the Yangtze River Basin and Jiangnan region encountered their most intense precipitation event since 1961. Extreme weather events were particularly striking: An unusually early and severe heatwave swept through central and eastern China, becoming the second most intense high-temperature event in recorded history. Autumn typhoon activity also displayed exceptional intensity, with Typhoon Yagi triggering significant impacts in Hainan, Guangdong, and Guangxi. Although drought conditions were generally mild overall, notable seasonal and regional disparities emerged, especially in the winter–spring droughts affecting southwestern China. Conversely, cold outbreaks occurred more frequently than usual, and convective weather events exhibited heightened activity. Moreover, dust storm activity remained relatively limited.</div><div>摘要</div><div>2024年中国气候异常特征显著, 呈现突出的暖湿气候态势. 全国平均气温创1951年以来历史新高, 春, 夏, 秋三季气温均为历史最高; 年降水量位列历史第四高位, 四季降水均偏多, 其中长江流域和江南地区降水量更创1961年以来最强纪录, 极端天气事件尤为突出: 中东部地区遭遇历史罕见的早发强高温天气, 高温强度居历史第二; 秋季台风活动异常活跃, 台风\"摩羯\"给海南, 广东, 广西带来显著影响. 尽管全年干旱总体偏轻, 但季节性和区域性差异明显, 西南地区冬春连旱尤为显著. 与此同时, 冷空气过程较常年偏多, 强对流天气呈现高发态势, 而沙尘天气则相对偏少.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 5","pages":"Article 100661"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-09-01Epub Date: 2025-01-10DOI: 10.1016/j.aosl.2025.100591
Yuanyan Xu, Wenkai Li
Due to the high elevation and cold climate of the Tibetan Plateau, the western region retains extensive snow cover during the summer, which can exhibit rapid variability over the course of just a few days. This study utilizes numerical experiments to investigate the atmospheric response to extreme Tibetan Plateau snow cover (TPSC) events on a subseasonal timescale during summer. The results indicate that the subseasonal variations in TPSC exert limited impact on nonlocal atmospheric circulation and temperature during this period. Nevertheless, local surface energy and atmospheric temperature exhibit rapid cooling responses to increased snow cover. Specifically, an increase in snow cover over the western Tibetan Plateau leads to a sharp rise in surface albedo, resulting in a reduction in land surface energy and a negative response in the diabatic heating rate from the surface to 350 hPa locally. This negative diabatic heating response subsequently causes a decline in both surface and overlying atmospheric temperatures. The temperature response is confined to the western Tibetan Plateau and extends vertically from the surface to approximately 350 hPa. These extreme TPSC events and their associated atmospheric impacts occur within a two-week timescale.
{"title":"Subseasonal impact of extreme Tibetan Plateau snow cover on the local atmosphere in summer","authors":"Yuanyan Xu, Wenkai Li","doi":"10.1016/j.aosl.2025.100591","DOIUrl":"10.1016/j.aosl.2025.100591","url":null,"abstract":"<div><div>Due to the high elevation and cold climate of the Tibetan Plateau, the western region retains extensive snow cover during the summer, which can exhibit rapid variability over the course of just a few days. This study utilizes numerical experiments to investigate the atmospheric response to extreme Tibetan Plateau snow cover (TPSC) events on a subseasonal timescale during summer. The results indicate that the subseasonal variations in TPSC exert limited impact on nonlocal atmospheric circulation and temperature during this period. Nevertheless, local surface energy and atmospheric temperature exhibit rapid cooling responses to increased snow cover. Specifically, an increase in snow cover over the western Tibetan Plateau leads to a sharp rise in surface albedo, resulting in a reduction in land surface energy and a negative response in the diabatic heating rate from the surface to 350 hPa locally. This negative diabatic heating response subsequently causes a decline in both surface and overlying atmospheric temperatures. The temperature response is confined to the western Tibetan Plateau and extends vertically from the surface to approximately 350 hPa. These extreme TPSC events and their associated atmospheric impacts occur within a two-week timescale.</div><div>摘要</div><div>青藏高原海拔高, 气候寒冷, 其西部地区在夏季仍有积雪覆盖, 且积雪变化可能在数日内迅速发生. 本文通过数值试验研究了大气对夏季青藏高原极端积雪事件的次季节响应. 结果表明, 尽管极端积雪事件对非局地大气环流及温度的影响有限, 但局地地表能量收支和大气温度对积雪增加表现出快速的冷却响应. 具体而言, 青藏高原西部积雪增加会导致地表反照率迅速上升, 从而减少地表能量输入. 此变化引发了局地地表至350 hPa高度的非绝热加热率的负异常响应, 进而导致地表及上空大气温度下降. 气温响应主要局限于青藏高原西部, 并且从地表垂直延伸至约350 hPa高度. 上述夏季青藏高原极端积雪事件及其大气影响发生在两周时间内.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 5","pages":"Article 100591"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-07-01Epub Date: 2024-11-12DOI: 10.1016/j.aosl.2024.100571
Meng Tian , Ying Wen , Lihong Meng , Ye Zhang , Shu Liu , Yang Guo
Fog is a highly complex weather phenomenon influenced by numerous factors. This study investigated the impact of the Changbai Mountains’ topography on the formation and development of spring fog in the Bohai Sea. From 12 to 14 May 2021, the Bohai region experienced a sea fog event. Utilizing Himawari-8 satellite data, ERA5 reanalysis dataset, land and sea station observations, the WRF model, a topography sensitivity experiment, and backward trajectory tracking, the influence of the Changbai Mountains’ topography on the evolution of this sea fog event was assessed. Results indicated that the Changbai Mountains’ topography significantly impacted the propagation and concentration of the sea fog through dual effects—namely, the Venturi Effect and Foehn Clearance Effect. Comparative simulations incorporating and excluding the Changbai Mountains revealed that its topography favored weak convergence (Venturi Effect) of low-level airflow over the Bohai Sea induced by a high-pressure system, promoting westward fog expansion. Additionally, the backward trajectory analysis further indicated that the Foehn Clearance Effect of the Changbai Mountains extended its influence far beyond the immediate lee side, contributing to significant changes in atmospheric conditions such as reductions in relative humidity and increases in potential temperature. The dry, warm foehn contributed to a reduction in the liquid water content, ultimately leading to the weakening or even dissipation of the sea fog in the region close to the Changbai Mountains. This study emphasizes the crucial role of the Changbai Mountains’ topography in the development and evolution of fog, providing valuable insights for forecasting fog in regions with complex terrain.
{"title":"Impact of the Changbai Mountains’ topography on spring fog over the Bohai Sea","authors":"Meng Tian , Ying Wen , Lihong Meng , Ye Zhang , Shu Liu , Yang Guo","doi":"10.1016/j.aosl.2024.100571","DOIUrl":"10.1016/j.aosl.2024.100571","url":null,"abstract":"<div><div>Fog is a highly complex weather phenomenon influenced by numerous factors. This study investigated the impact of the Changbai Mountains’ topography on the formation and development of spring fog in the Bohai Sea. From 12 to 14 May 2021, the Bohai region experienced a sea fog event. Utilizing Himawari-8 satellite data, ERA5 reanalysis dataset, land and sea station observations, the WRF model, a topography sensitivity experiment, and backward trajectory tracking, the influence of the Changbai Mountains’ topography on the evolution of this sea fog event was assessed. Results indicated that the Changbai Mountains’ topography significantly impacted the propagation and concentration of the sea fog through dual effects—namely, the Venturi Effect and Foehn Clearance Effect. Comparative simulations incorporating and excluding the Changbai Mountains revealed that its topography favored weak convergence (Venturi Effect) of low-level airflow over the Bohai Sea induced by a high-pressure system, promoting westward fog expansion. Additionally, the backward trajectory analysis further indicated that the Foehn Clearance Effect of the Changbai Mountains extended its influence far beyond the immediate lee side, contributing to significant changes in atmospheric conditions such as reductions in relative humidity and increases in potential temperature. The dry, warm foehn contributed to a reduction in the liquid water content, ultimately leading to the weakening or even dissipation of the sea fog in the region close to the Changbai Mountains. This study emphasizes the crucial role of the Changbai Mountains’ topography in the development and evolution of fog, providing valuable insights for forecasting fog in regions with complex terrain.</div><div>摘要</div><div>利用Himawari-8卫星数据, ERA5再分析数据, 陆地与海上站点观测, WRF模式, 地形敏感性试验以及后向轨迹分析, 研究了长白山地形对渤海春季海雾生消演变的影响. 结果表明, 长白山地形通过狭管效应和焚风清除效应对海雾的传播和浓度有显著影响. 模拟结果显示, 长白山地形有利于渤海上空低层气流的弱汇合, 促进海雾向西传播. 此外, 后向轨迹分析显示, 长白山的焚风清除效应远超其背风坡区域, 导致相对湿度降低和位温升高等大气条件的显著变化. 干暖焚风降低了雾区的液态水含量, 导致靠近长白山的海雾减弱甚至消散. 本研究强调了长白山地形对渤海海雾发展演变的重要作用, 为复杂海域的雾预报提供参考.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 4","pages":"Article 100571"},"PeriodicalIF":2.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144169739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-07-01Epub Date: 2024-10-25DOI: 10.1016/j.aosl.2024.100561
Aoqi Zhou , Chaoxia Yuan
The intensification of extreme precipitation (EP) under global warming presents a substantial risk to human safety and societal progress. Studying the specific impacts of global warming on rare EP events in China not only enhances the comprehension of these shifts, but also paves the way for the development of proactive strategies to alleviate associated damages. Results from large-ensemble simulation data demonstrate that global warming has led to an enhancement in once-in-a-decade EP events in parts of western and central China over the past few decades, with the strengthening of the South Asia high (SAH) caused by global warming playing a dominant role. The strengthening of the SAH corresponds to an intensification and westward extension of the western Pacific subtropical high in the lower troposphere. The region between these two systems experiences enhanced upward motion and increased southwesterly water vapor transport, leading to a rise in climatological precipitation in western and central China, thereby raising the threshold for once-in-a-decade EP events.
{"title":"Global warming intensifies once-in-a-decade extreme precipitation in summer in China","authors":"Aoqi Zhou , Chaoxia Yuan","doi":"10.1016/j.aosl.2024.100561","DOIUrl":"10.1016/j.aosl.2024.100561","url":null,"abstract":"<div><div>The intensification of extreme precipitation (EP) under global warming presents a substantial risk to human safety and societal progress. Studying the specific impacts of global warming on rare EP events in China not only enhances the comprehension of these shifts, but also paves the way for the development of proactive strategies to alleviate associated damages. Results from large-ensemble simulation data demonstrate that global warming has led to an enhancement in once-in-a-decade EP events in parts of western and central China over the past few decades, with the strengthening of the South Asia high (SAH) caused by global warming playing a dominant role. The strengthening of the SAH corresponds to an intensification and westward extension of the western Pacific subtropical high in the lower troposphere. The region between these two systems experiences enhanced upward motion and increased southwesterly water vapor transport, leading to a rise in climatological precipitation in western and central China, thereby raising the threshold for once-in-a-decade EP events.</div><div>摘要</div><div>全球变暖下极端降水 （EP） 的加剧对人类安全和社会发展构成了重大威胁. 研究全球变暖对中国罕见极端降水事件的影响， 不仅能加深大家对这些变化的理解， 还为制定应对政策铺平了道路. 大样本模拟数据表明， 在过去几十年中， 全球变暖加剧了中国西部和中部部分地区十年一遇的极端降水事件， 其中因全球变暖而增强的南亚高压 （SAH） 起到了主导作用. SAH的增强与对流层低层西太副高的增强西伸密切相关. 这两个系统间的区域经历了更强的上升运动和增强的西南水汽输送， 导致中国西部和中部的气候态降水增加， 从而提高了十年一遇极端降水事件的阈值.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 4","pages":"Article 100561"},"PeriodicalIF":2.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144169723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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