2020年2月14—17日吉林地区一次暴雪天气过程成因分析

Analysis of the Causes of A Heavy Snow Weather Process in Jilin Province from February 14 to 17,2020

利用地面观测资料、NCEP再分析资料、常规观测资料等对分析2020年2月14—2月17日吉林地区出现的一次暴雪天气过程成因。结果表明:高空急流、低空锋区、地面倒槽及暖式切变是此次暴雪天气的主要影响系统,再加上地面西南低压倒槽及西太平洋高压的稳定维持,促进了暴雪天气的出现和维持;850 hPa处存在2个强水汽通量中心,辽宁以东和吉林省以南的水汽辐合区强度较大,深厚湿层与强烈水汽辐合的作用向暴雪落区内输送了源源不断的水汽条件;从850 hPa到地面,降雪天气还没有出现前一直都是能量在集聚;降雪期间,假相当位温的维持也是暴雪天气维持的关键,一旦该数值下降,说明后续能量不足,降雪强度减弱直至结束;这种中低层辐合、高层辐散的配置,对于强降雪天气的发生和维持均较为有利。

This article uses ground observation data,NCEP reanalysis data,conventional observation data,etc.to analyze the causes of a heavy snow weather process that occurred in the Jilin region from February 14 to 17,2020.The results indicate that the main influencing systems of this blizzard are the high-altitude jet stream,low-level frontal zone,ground trough,and warm shear.In addition,the stable maintenance of the southwest low-pressure trough and the western Pacific high pressure on the ground have promoted the occurrence and maintenance of the blizzard weather;There are two strong water vapor flux centers at 850 hPa,and the water vapor convergence areas to the east of Liaoning and south of Jilin Province have greater intensity.The deep wet layer and strong water vapor convergence transport a continuous stream of water vapor conditions to the snowstorm area;From 850 hPa to the ground,energy has been accumulating until snowfall occurs;During snowfall,the maintenance of false equivalent temperature is also the key to maintaining blizzard weather.Once this value decreases,it indicates insufficient energy in the future,and the snowfall intensity weakens until it ends;This configuration of mid low level convergence and high level divergence is more favorable for the occurrence and maintenance of heavy snowfall weather.