基于风廓线雷达的一次台风暴雨风场垂直结构演变分析OA

Based on conventional meteorological observation data,automatic weather station hourly and minute high-resolution data,data from four wind profiler radars,the CMA best-track dataset,and NCAR(National Center for Atmospheric Research)reanalysis data,this study investigates the heavy precipitation process caused by Typhoon Doksuri in Shandong Province from July 28 to 30,2023.The results indicate that:(1)The heavy precipitation event caused by Typhoon Doksuri in Shandong can be roughly divided into three stages,dominated sequentially by the typhoon inverted trough,the typhoon residual low-pressure circulation,and the southeasterly low-level jet.(2)Typhoon inverted trough stage:Characterized by convective precipitation,the onset of heavy rainfall is closely linked to the strengthening and thickening of mid-level northeasterly winds,accompanied by the transition of low-level winds from northeasterly to southeasterly.The increase in the low-level jet index exhibits a delayed response in indicating precipitation.The sudden increase in vertical wind shear corresponds to the initiation of precipitation,while its decrease signals the end.(3)Typhoon residual low-pressure circulation stage:Dominated by stratiform precipitation,the occurrence of heavy rainfall aligns with the strengthening of mid-to-upper-level southeasterlies and the intensification of low-level northeasterlies turning into southeasterlies.A uniform southeasterly profile throughout the column corresponds to continuous light rain.The surge in the low-level jet index precedes the intensification of rainfall by approximately 1 hour,and the oscillation of this index relates to sustained light precipitation.Prior to heavy rainfall,the mid-level vertical wind shear increases first,leading the strong precipitation by 3 to 4 hours.The expansion of the strong mid-level shear center toward both upper and lower levels acts as an indicator for heavy precipitation.(4)Southeasterly jet stage:A significant enhancement of low-level southeasterly winds corresponds to heavy rainfall.The increase in the low-level jet index precedes the peak rainfall intensity by about 2 hours.During this stage,the mid-level vertical wind shear remains consistently high at around 10 m·s-1.Before heavy precipitation occurs,the mid-level vertical wind shear further increases,leading the intense rainfall by 5 to 6 hours.(5)The vertical velocity measured by the wind profiler radars closely matches the timing of precipitation,exhibiting a positive correlation between velocity magnitude and precipitation intensity.