河西走廊东部"8·13"暴雨极端性和成因OA

Using conventional upper-air and surface observations,hourly precipitation,FY-4A satellite imagery,and ERA5 reanalysis data,we diagnostically analyzed the extremity and meteorological causes of a rainstorm event that occurred on 13 August 2022 in the eastern Hexi Corridor.The results indicate that:(1)The rainstorm was characterized by large accumulated rainfall,strong locality,and pronounced convective activity.The rainband extended from northwest to southeast and was mainly concentrated in Tianzhu County and Gulang County.(2)The daily precipitation at six stations exceeded historical maxima,and three stations recorded record-breaking hourly rainfall.Both the daily precipitation and the duration of short-duration heavy rainfall at Duoshi Town in Tianzhu County exceeded historical records in the eastern Hexi Corridor.(3)The rainstorm occurred under the synergistic influence of multi-scale weather systems,including a mid-to upper-level shortwave trough,a low-level shear line,and a surface cold front.Compared with other historical events,stronger moisture supply,vertical motion,and extremely unstable energy conditions jointly contributed to the extremity of this rainstorm.(4)The development and intensification of multiple convective cells,along with their convergence under topographic influence,directly caused the high rainstorm intensity and prolonged duration.(5)Orographic lifting enhanced upward motion and intensified local convection.