2018年4月成都地区两次寒潮天气过程对比分析

Comparative Analyses of Two Cold Wave Processes in Chengdu in April,2018

本研究利用常规地面观测资料、探空资料和NCEP资料对2018年影响成都地区的两次寒潮天气过程进行对比分析,研究结果表明:两次寒潮均是在前期强烈升温基础上,冷空气向南侵袭造成的;两次过程中高纬环流形势均表现为"两槽一脊"型.过程I有横槽转竖现象,地面冷高压先分裂后整体南下,冷空气南下速度快,持续时间短,气温骤降,局地降雨强度大,普遍出现6～8级瞬时大风.过程II是由南支槽和850hPa东北回流共同造成,地面冷高压分裂南下,冷空气南下速度慢,持续时间长,但日降温幅度较小,平均风力较大,降水持续时间更长.

Based on the routine surface observation, sounding data and the NCEP, two cold waves occurred in 2018 in Chengdu have comparatively been analyzed. The results show that the twice waves are based on the warming strongly in the previous period, and the cold air breaks out southward. The circulation patterns show two through and a ridge at middle and high latitudes. The process I has the phenomenon of transverse trough switch zonal, the surface cold high pressure first split after the whole south, the cold air moved down south quickly and continued for a short time, the temperature dropped suddenly, the local rainfall intensity was great, and the 6-8 level instantaneous wind was generally appeared. The process II was caused by the Indian-Myanmar trough and the northeasterly return from 850 hPa. The surface cold high pressure split south, the cold air moved down South slowly and continued for a long time. But the range of daily drop in temperature was small, the average wind was larger and the precipitation lasted longer.