The Cause Analysis and Successful Early Warning of an Extreme Rainstorm Controlled by Subtropical High
On October 8th,2022,a historic extreme rainstorm hit Mangnuo Township in Shuangjiang County,Lin-cang City,with a maximum hourly rainfall of 57.2mm.The cause of this rainstorm is revealed through the comprehensive analysis of high-altitude observations,regional automatic weather station measurements,ERA5 reanalysis data,FY-2G satellite imagery,Doppler weather radar information and other data.①The large-scale circulation background of this pro-cess is the heavy rainfall triggered by the mesoscale system under the control of the strong subtropical high.②During heavy rainfall,the atmosphere is unstable,there are warm and wet bottom layer and dry and cold upper layer,low lifting conden-sation height and free convection height;The occurrence of heavy rainfall corresponds to the high value of water vapor trans-port and water vapor convergence,the low-level convergence and the mid-high-level divergence,and coexists with the strong vertical rising movement.③The two periods of heavy correspond to different radar echo characteristics.In the initial period,there is no large-scale rainfall echo,and there is a medium γ scale convection echo locally;The range of rainfall echo in the next period expands,forming a train effect.④The topography of Mangnuo Township and the east-south flow at low level play a key role in triggering and maintaining the mesoscale convective system.⑤The"1262"service mode has is-sued warnings in advance,which has effectively warned of heavy rainfall at night and avoided casualties,becoming a suc-cessful case of early warning linkage.
extreme rainstormsubtropical highmesoscale systemLincangprogressive meteorological service
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