“海棠”残留低压引发鲁中东部暴雨中尺度特征分析  

Mesoscale Characteristics of the Rainstorm Caused by the Residual Low Pressure of Typhoon Haitang in East of Central Shandong Province

作　　者：王文波 李晓利 赵华 韩晓 王旭 Wang Wenbo;Li Xiaoli;Zhao Hua;Han Xiao;Wang Xu(Weifang Meteorological Office, Weifang 261011, China;Dongying Meteorological Office, Dongying 257091, China)

机构地区：[1]山东省潍坊市气象局,山东潍坊261011 [2]山东省东营市气象局,山东东营257091

出　　处：《气象与环境科学》2021年第2期80-86,共7页Meteorological and Environmental Sciences

基　　金：环渤海区域项目(QYXM201707);山东省气象局课题(2018sdqxm16,SDYBY2020-07)。

摘　　要：利用多普勒天气雷达、边界层风廓线雷达和FNL全球分析资料,对2017年8月2—3日“海棠”残留低压引发的鲁中东部暴雨中尺度特征进行分析。结果表明:(1)中纬度西风槽与低压倒槽的合并加强是此次暴雨发生的重要原因。(2)低空20 m·s^(-1)以上强东南急流向超低空快速扩展到1 km以下高度,对应降水的开始和增强;2 km以下东南风、25 km偏南风急流和5 km以上西北风的垂直风场结构,对应着短时强降水时段;5 km以下高度均转为西南风且低空急流强度的明显减弱,对应着降水的减弱和结束。(3)低空急流向下扩展,使大气湿层加厚、斜压锋区加强,中层干冷空气的侵入触发了不稳定能量释放。(4)低空急流指数对低空急流的脉动及向超低空扩展程度有密切的关系,指数I的峰值出现时刻较雨强的峰值出现时刻提前了2 h左右。(5)中尺度切变线和辐合线是鲁中东部暴雨的直接影响系统,对强降水的落区有很好的指示作用。Using the data of Doppler weather radar and boundary layer wind profiling radar and the FNL global analysis data,the meso-scale characteristics of the rainstorm in east of central Shandong province caused by the residual low pressure of Typhoon Haitang in 23 August 2017 are analyzed.The results show that:(1)The merging and strengthening of mid-latitude westerly trough and low-pressure inverted trough was an important reason for the rainstorm this time.(2)The strong southeasterly jet stream above 20 m·s^(-1)rapidly descended to a height below 1 km,causing the onset and enhancement of precipitation.The vertical structures of the southeasterly winds below 2 km height,southerly winds within 25 km height and northwesterly winds over the hieght 5 km corresponded to the periods of short-time severe rainfalls.When the height below 5 km turned into the southwesterly wind and the intensity of low-level jet stream obviously decreased,the severe precipitation got weakened and died out gradually.(3)The low-level jets extended downward,making the thickening of atmospheric wet layer and the strengthening of baroclinic frontal zone.Besides,the intrusion of cold-dry airs from the middle layer triggered the release of unstable energy.(4)The low-level jet index is closely related to the fluctuation and downwared development of low-level jet to the further low altitude.The time with peak value of index I is about 2 hours earlier than the appearence of the rainfall intensity peak.(5)The mesoscale shear line and convergence line are the direct influence systems of rainstorms in the eastern part of central Shandong,and they could be good indicators of the falling area of severe precipitation.

关 键 词：暴雨 风廓线 低空急流 中尺度切变线 

分 类 号：P458.1+21.1[天文地球—大气科学及气象学]