一次东北冷涡背景下的飑线天气过程诊断分析

Diagnostic Analysis of a Squall Line Weather Process Under the Background of Northeast Cold Vortex

利用常规气象观测资料、NCEP/NCAR 1°×1°逐6 h再分析资料及FY-2E水汽图等资料,对2016年6月13 14日发生在山东的一次飑线天气过程进行综合分析。结果表明:此次大范围强对流过程是在东北冷涡背景下接连两次飑线影响而产生的,地面中尺度辐合线是触发不稳定能量释放的重要机制;强对流区上空的高CAPE值、中层干冷和低层暖湿的温湿垂直分布及中等以上强度的深层垂直风切变,都是这次强对流发生和维持的有利环境条件;强对流过程的干侵入主要来自于高空冷涡后部的偏北气流,引导冷空气向南入侵,随着干侵入的增强,其前侧的对流也随之增强;水汽图上"暗缝"的移动方向与500 h Pa气流的方向关系密切。

Using the conventional observation data, NCEP/NCAR 1°× 1° 6 h reanalysis data and FY -2E water vapor images, the synoptic characteristics of a squall line process in Shandong during June 13-14 2016 were analyzed. The results showed that the large scale strong convection process happened by twice squall lines under the northeast cold vortex, and the surface mesoscale convergence was an im-portant trigger mechanism for the release of unstable energy. The high CAPE value, dry cold air in the middle , wet warm in the lower and the above average deep vertical wind shear were all the favorable envi-ronmental conditions for the occurrence and maintenance of this strong convection process. The dry intru-sion was mainly from the northerly wind at the back of the high altitude cold vortex, led cold air into south, with the increasing of dry intrusion, the convection on the front side also increased. The moving direction of “dark slot” on the water vapor images was closely related to the airflow direction at 500 hPa.