大气科学2025，Vol.49Issue(2)：491-506,16.DOI:10.3878/j.issn.1006-9895.2303.23017
基于天气分型的四川盆地西侧极端强降水事件环流异常配置与演变特征
Configuration of Large-Scale Circulation Anomalies and Their Evolution for Extreme Heavy-Precipitation Events in the West of the Sichuan Basin Based on Classified Weather Patterns
摘要
Abstract
The western side of the Sichuan Basin is one of the regions in China that experiences the highest frequency of extreme heavy precipitation events(HPEs).However,due to terrain complexity and atmospheric circulation systems,the formation mechanism of HPEs remains elusive.Based on the gauged data by the China Meteorological Administration from 2001 to 2020,GPM-IMERG precipitation data,and ERA5 reanalysis data,we selected 100 extreme HPEs that occurred in the west of the Sichuan Basin and classified them into three categories using the K-means clustering method.Then,the anomalies of atmospheric circulation and their evolution with respect to different HPE categories were explored.The results show that during the precipitation period,the geopotential height is characterized by a positive anomaly at the upper level(200 hPa)and negative anomaly at the lower level(850 hPa),together with enhanced vertical wind speed,demonstrating a"top-cold and bottom-warm"atmospheric temperature structure and increased water vapor transport from the low-latitude ocean area.However,the atmospheric circulation configuration of anomalies,including the South Asia high(SAH),Western Pacific Subtropical high(WPSH),and upper-level westerly jet,shows an obvious difference and plays a dominant role in shaping the precipitation formation of different types and associated water vapor transport.For category 1(HPEs with the highest frequency of occurrence),associated water vapor transport mainly comes from the Bay of Bengal and the South China Sea and is controlled by the Indian and East Asian monsoons.For category 2,HPEs occur with strengthened WPSH,and its water vapor mainly comes from the South China Sea,while the water vapor transport from the Bay of Bengal is restricted.For category 3,its water vapor transport is mainly controlled by the East Asian monsoon.Before the occurrence of HPEs,the Rossby wave action shows an increasing trend,atmospheric vertical wind speed increases significantly,and temperature anomaly is more significant.These features are conducive to the occurrence of extreme precipitation events.Moreover,the results indicate that changes in the WPSH position and intensity on synoptic time scales are better indicators for predicting heavy precipitation formation compared with SAH.关键词
四川盆地/大尺度环流异常/极端强降水Key words
Sichuan Basin/Large scale circulation/Extreme heavy precipitation分类
天文与地球科学引用本文复制引用
陈龙光,陈斌,赵瑞瑜,徐祥德..基于天气分型的四川盆地西侧极端强降水事件环流异常配置与演变特征[J].大气科学,2025,49(2):491-506,16.基金项目
国家自然科学基金—气象联合基金重点项目U2242202,国家自然科学基金项目42475010,国家重点研发计划项目2023YFC3010700 Funded by Joint Meteorological Fund of National Natural Science Foundation of China(Grant U2242202),National Natural Science Foundation of China(Grant 42475010),National Key Research and Development Program of China(Grant 2023YFC3010700) （Grant U2242202）
