Macro and Micro Characteristics of Extreme Precipitation Systems and Non-extreme Precipitation Systems over South China During the Warm Season Based on TRMM Observations from 1998 to 2013
WEI Huihua
FU Jiaolan
TIAN Zhiguang
CHEN Hao
XU Weixin
Abstract：This study investigates the precipitation structures and environmental conditions of Extreme Precipitation Events(EPEs)over South China during the warm season(April-September,1998-2013)using TRMM satellite data.The structure and environmental characteristics of the Non-Extreme Precipitation Events(NonEPEs),including thunderstorm,and the convective NonEPEs(NonEPE_Inten),which lacks extreme precipitation,are compared and analyzed.The hourly extreme precipitation threshold is defined using the 99.9th percentile of hourly precipitation data of about 1 500 stations in South China during 1981-2013.EPE(NonEPE)refers a convective system in which the intensity of the precipitation center meets(does not meet)the extreme hourly precipitation threshold,and the precipitation area is at least 100 km2.Results indicate that the horizontal scale of EPE over South China exhibits meso-βscale(45-50 km),which is the scale of thunderstorms.Most EPEs occur in organized mesoscale convective systems(horizontal scale>100 km),while NonEPEs primarily occur in relatively small-scale convective systems(horizontal scale<100 km).Satellite microwave observations indicate that EPEs contain abundant ice particles.The vertical structure of EPE is significantly different from that of strong convections.The radar reflectivity of EPE(non-EPE)increases by 6-7 dBZ(2-3 dBZ)below the melt layer,indicating EPE has a more active warm rain or collision-coalescence process with higher raindrop growth efficiency.In terms of environmental conditions,EPE show higher relative humidity,stronger 700-925 hPa wind shear,thicker warm cloud depth,weaker convective effective potential energy(CAPE),and lower low-level temperature.
Keywords：extreme precipitationstrong convectionmesoscale convective systemspaceborne precipita-tion radar
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：12( 541-552 )