2020年7月拉萨市两次中等强度降水过程对比分析

Comparative Analysis of Two Moderate Intensity Precipitation Processes in Lhasa in July 2020

利用Micaps常规观测资料以及数值预报、物理量诊断、卫星云图、地面自动站等资料,对7月9日20:00~10日20:00和7月19日20:00~20日20:00出现的两次相似环流背景、但最强中心落区不一致的两次降水过程进行分析。结果表明:两次过程500 hPa上中高纬均为两脊一槽型,在本地上空均无明显的影响系统,均为西路冷空气,但冷空气南压过程不一致,最终将709过程认定为高压脊型降水,719过程认为高压外围型或暖云降水、两次过程水平动力结构不一致,719过程更有利于水平运动的发展、两次过程垂直动力结构不一致,709过程更有利于垂直运动的发展、两次过程的主体云系来源不同,709过程的主体云系来自北部,而719过程的主体云系来自南部。

In this paper,the background of two similar circulation occurred from 20:00 to 20:00 on July 9 and 20:00 to 20:00 on July 19,using micaps conventional observation data and numerical prediction,physical quantity diagnosis,satellite cloud map,ground automatic station and so on,However,the two precipitation processes in the strongest central drop area are analyzed.According to the results,the upper and middle latitudes of 500 hPa are two ridges and one groove,There is no obvious influence system over the local sky,Cold air on the west road,But the cold air’s southern pressure is inconsistent,Finally,the 709 process is considered as high pressure ridge precipitation,In the 719 process,it is considered that the horizontal dynamic structure of high pressure peripheral type or warm cloud precipitation and two processes is inconsistent,The 719 process is more conducive to the development of horizontal motion,and the vertical dynamic structure of the two processes is inconsistent.The 709 process is more conducive to the development of vertical motion,and the main cloud system sources of the two processes are different,The main cloud system of the 709 process is from the north,while the main cloud system of the 719 process comes from the south.