摘要: |
台风“暹芭”不仅是 2022年首个登陆中国的台风,也是自 2015年台风“彩虹”以来登陆粤西的最强台风,其登陆后减弱的残余环流不断北移,深入内陆与中纬度西风槽相结合,给我国东部地区带来了影响范围广且持续性强的暴雨过程,为了研究引起这种罕见天气过程的影响因子,基于区域中尺度预报系统 CMA-MESO(China Meteorological Administration Mesoscale Model)5.1 版本对台风“暹芭”残余环流北上过程共设计 6 组试验进行数值模拟和诊断分析。结果表明:台风“暹芭”东西两侧的南亚高压和副热带高压两个反气旋有利于低压环流北上,在我国东部广阔平原和丘陵的地形条件下,槽前西南气流不断引导其快速向东北方向移动;台风“暹芭”进入渤海后,受槽后干冷空气影响,冷空气入侵环流底部,斜压性增强,暖湿气流显著抬升,对流不稳定结构进一步增强;同时有来自南海的深厚西南暖湿气流和台风“艾利”外围源源不断的水汽输送,在地形、动热力和水汽条件的共同作用下,台风“暹芭”残余环流在我国东部引发大暴雨过程。 |
关键词: 台风“暹芭” 地形 西风槽 水汽 暴雨 |
DOI:10.16032/j.issn.1004-4965.2024.072 |
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Causes and Numerical Simulation of Heavy Rainfall in Eastern China Triggered by Residual Circulation of Typhoon“Chaba” |
MA Yixuan1, YU Fei2,3, XU Guoqiang2,3
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1. Shaanxi Provincial Meteorological Service, Xi’an 710014, Chian;2. State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, China;3. CMA Earth System Modeling and Prediction Center, Beijing 100081, China
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Abstract: |
Typhoon Chaba was not only the first typhoon to make landfall in China in 2022, but also the most potent to hit western Guangdong since Typhoon Mujigae in 2015. Its residual circulation, after landfall and subsequent weakening, continued to move northward, penetrate deep into the Chinese mainland and merge with the mid-latitude westerly trough. This resulted in a widespread, intense, and persistent rainstorm in eastern China. To investigate the factors influencing this unusual weather event, the present study designed six sets of experiments using the regional mesoscale forecast system CMA-MESO version 5.1 to simulate and diagnose the northward progression of Chaba’s residual circulation. The results showed that the two anticyclonic circulations of South Asian high pressure and subtropical high pressure on the east and west sides of Chaba were conducive to the northward movement of the low-pressure circulation. Under the influence of the broad plains and hills in eastern China, the southwestern airflow ahead of the trough consistently directed it towards the northeast. After Chaba entered the Bohai Sea, it was affected by the dry, cold air following the trough. This led to the invasion of cold air at the base of the circulation, enhancing baroclinicity, significantly lifting the warm, humid airflow, and further intensifying convective instability. At the same time, there were deep, warm, and humid southwestern airflow from the South China Sea and continuous water vapor transport from the periphery of Typhoon Aere. Under the combined influence of topography, dynamic and thermal forces, and water vapor conditions, the residual circulation of Chaba triggered the heavy rainstorm in eastern China. |
Key words: Typhoon Chaba topography westerly trough water vapor rainstorm |