Circulation Characteristics of Torrential Rain in Eastern Guangdong Caused by Typhoons Landing in Fujian
LIANG Jiehua
CHENG Zhengquan
CHEN Hao
CHEN Weiqing
HUANG Wenjun
WANG Meng
Abstract：Using the Yearbook of Tropical Cyclone(1990-2019)from the China Meteorological Administration,ERA5 0.25 °×0.25 ° hourly reanalysis data,and 24-hour(20:00-20:00)rainfall observations from national stations in eastern Guangdong,this study classifies and analyzes the circulation characteristics of torrential rain in eastern Guangdong induced by westward-moving typhoons after landfall in Fujian Province.Statistical classification and composite analysis methods are employed.Results show that torrential rain occurs more frequently on the day after typhoon's landfall than on the landfall day itself.A mid-level position along the robust edge of a strong subtropical high favors heavy rainfall development.The low-level wind fields associated with heavy rain in eastern Guangdong are divided into three types:the typhoon trough type with prolonged precipitation duration;the southwesterly jet type where precipitation typically begins as the jet moves onshore,with rainfall intensity scaling with jet strength;and the southeasterly flow type where rainfall intensity is closely related to terrain,where windward slopes significantly enhance precipitation.Light-rainfall typhoons exhibit inherently weaker moisture convergence and vertical motion,which are insufficient to drive intense precipitation.Analysis of physical parameter configurations shows heavy-rainfall typhoons superior conditions than light-rainfall typhoons:the southwestern jet type has optimal warm and moist conditions and can generate widespread torrential rain even with moderate dynamic forcing;the typhoon trough type and southeasterly flow type exhibit peak dynamic but slightly inferior thermal conditions,with>100 mm rainfall areas collocated with upper-level divergence centers.Regarding moisture conditions,stronger eastward water vapor transport within typhoon circulation benefits moisture supply to eastern Guangdong,though attention should be paid to other developing tropical systems that may weaken or disrupt this moisture transport.
Keywords：westward tracktyphoontorrential raincirculation characteristicsphysical parameters
Publication Date：2025-08-30
Online Publishing Date：2025-09-23(First online date of this platform, not the publication date of the document)
Pages：9( 495-503 )