Characteristics of Radar 3D Retrieved Wind Fields During Extreme Heavy Rainfall in the Pearl River Delta Caused by the Remnant Vortex of Typhoon"Haikui"
LI Yuguang
ZHANG Kaifeng
WU Bin
YU Lefu
Abstract：To improve the accuracy of forecasting extreme heavy rainfall associated with typhoons,this study utilizes 3D retrieved wind fields from Guangdong S-band radars and Foshan X-band radars to analyze the relationship among low-level jets,structural changes in the remnant vortex of Typhoon"Haikui,"and rainfall distribution.The results show the following.(1)The development of the jet on the southeastern side of the remnant vortex is closely related to heavy rainfall.This jet first appears at low levels and gradually ex-tends upward,approaching the vortex center,with heavy rainfall areas shifting from the right side of the vor-tex toward its center as the jet strengthens.(2)The low-level jet causes the remnant vortex center to tilt ver-tically,leading to the development of a new circulation center.The new and original centers merge as they move closer,causing the vortex to slow down and meander west of the Pearl River Estuary,resulting in pro-longed heavy rainfall over the Pearl River Delta.(3)The intensification and northward movement of the jet over the northern South China Sea lead to a renewed strengthening of rainfall in the Pearl River Delta,with heavy precipitation occurring in areas where different airflows converge pairwise.This study provides critical insights into the dynamic mechanisms linking low-level jets and remnant vortex evolution with extreme rain-fall distribution,offering valuable references for improving typhoon-related heavy rainfall forecasting in coast-al metropolitan regions.
Keywords：synopticsTyphoon"Haikui"remnant vortexextreme heavy rainfallradar 3D retrieved wind fieldsPearl River Delta
Publication Date：2025-08-20
Online Publishing Date：2025-09-15(First online date of this platform, not the publication date of the document)
Pages：6( 43-47,52 )