Causes and Numerical Simulation of Heavy Rainfall in Eastern China Triggered by Residual Circulation of Typhoon"Chaba"
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.
国家科技期刊平台
NSTL
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