广州白云机场一次罕见的降水相态变化天气特征分析

摘要

利用常规气象观测资料和NCEP2再分析资料,对2016年1月24日广州白云机场出现的一次强冷空气过程的环流背景、主要影响系统以及期间降水多相态转换的天气特征进行了分析.结果表明:本次天气过程来源于一次横槽转竖型寒潮,冷锋、中低空切变线和低空急流给华南地区带来了较长时间的降水天气;白云机场上空存在多条0 ℃等温线和逆温层,探空廓线多次穿过0 ℃等温线,使得地面出现了雨和冰粒的相态转换;降水相态变化时暖层温度、0 ℃层高度、位势厚度、边界层高度、气柱云水量和地表抬升指数等指数均发生较大变化;当降水相态为雨时,暖层温度≥2 ℃,0 ℃层高度≤975 hPa;当降水相态为冰粒时,暖层温度≤0 ℃,0 ℃层高度≌1000 hPa.%By using conventional observation data and the NCEP2 reanalysis data,the circulation background,synoptic weather systems and the weather characteristics of precipitation phase transformation of a rare regional strong cold air on 24 January 2016 in Guangzhou BAIYUN Airport are discussed.The results show that:the strong cold air is caused by a cold wave of horizontal trough turning to longitudinal trough.The long time precipitation is caused by cold front,shear line and low level jet.There is an inversion layer and three 0 ℃ isotherms on the top of the airport during the strong cold air.The cross of temperature profile and 0 ℃ isotherms cause the precipitation phase transformation.Changes in precipitation phase are closely related to the strength of the warm layer temperature,0 ℃ layer height,geopotential thickness,planetary boundary layer height,cloud water of entire atmosphere and surface lifted index.When the precipitation phase is rain,the warm layer temperature is greater than or equal 2 ℃,and the 0℃ layer height is less than or equal 975 hPa. When the precipitation phase is ice pellets,the warm layer temperature is less than or equal 0 ℃, and the 0℃layer height is about 1000 hPa.