DIAGNOSIS OF SEVERE PRECIPITATION IN SHANGHAI UNDER INFLUENCE OF TYPHOON LEKIMA(2019)
HU Yan
YUE Caijun
GU Wen
LIU Dongwei
DENG Liping
YAO Yao
Abstract：Typhoon Lekima(2019),the 9th typhoon in 2019,caused severe rainstorm during its impact on Shanghai from August 9 to 11,2019.Based on the ERA-5 hourly reanalysis datasets and the ground observational data with high spatial and temporal resolution in Shanghai,the present study analyzed the causes of the severe precipitation by using the ageostrophic Q-vector decomposition method.The results showed that the severe precipitation associated with Lekima(2019)in Shanghai dominantly came from the spiral rainbands on the east side of the typhoon.The relative humidity at each boundary of the severe precipitation area varied significantly with time in the vertical direction.The vertical transport of water vapor and the water vapor flux in the whole atmosphere played an important role in this severe precipitation event.Furthermore,ageostrophic Q-vector decomposition was used to reveal that the large-scale system on the eastern boundary and the mesoscale system on the northern boundary played a major role.The maximum forcing center descended from the upper to the lower atmosphere after the whole atmosphere was uplifted when the typhoon made landfall,and the mesoscale forcing effect was more obvious than that of the large-scale forcing,which was conducive to the occurrence of severe precipitation.
Keywords：Typhoon Lekimasevere precipitationboundaryQ vector decompositiondiagnosis
Publication Date：2023-12-28
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：15( 883-897 )