遵义市冬末初春两次寒潮降雪天气过程对比分析

利用Micaps常规观测资料、NCEP/NCAR再分析资料、区域站加密观测资料,对遵义市2016年3月8—9日(过程Ⅰ)和2017年2月21—22日(过程Ⅱ)的两次寒潮降雪天气过程进行对比分析。结果表明:(1)500 h Pa横槽转竖和低槽东移是两次寒潮爆发的重要引导系统,过程Ⅰ属于横槽转竖型寒潮天气过程,过程Ⅱ寒潮属小槽发展型。(2)地面冷高压中心强度(冷源)及南下速度是预报寒潮的关键。(3)700 h Pa切变影响与降雪时段对应较好,在今后降雪预报中应作为重要影响系统加以关注。(4)湿层深厚,整层水汽含量高为降雪的显著特征。(5)有无融化层和融化层厚薄应作为降雪预报温度条件的关注重点。

Comparative Analysis of Two Cold Wave and Snowfall Weather Processes in Late Winter and Early Spring in Zunyi

By using MICAPS conventional observation data, NCEP/NCAR reanalysis data, regional station observation data of Zunyi City, 8 March 2016 9 (a process I) and in February 2017 21 a 22 day (process II) two cold snow weather process were analyzed. The results show that: (1) the horizontal trough of the 500hPa trough and the eastward movement of the low trough are the important guidance systems for the two cold wave eruption. The process I belongs to the transverse trough vertical cold wave weather process, and the process II cold wave belongs to the small trough development type. (2) The central strength of the ground cold high pressure (Leng Yuan) and the velocity of the south are the key to the prediction of the cold wave. (3) The effect of 700hPa shear is better than the snowfall period, and it should be paid attention to as an important influence system in the future snow forecast. (4) The wet layer is deep, and the high water vapor content in the whole layer is the notable feature of snowfall. (5) The focus of the melting layer and the thickness of the melting layer should be the focus of the snow forecast temperature condition.