广西长低温雨雪冰冻过程环流特征及低温扰动分析  

Analysis on Characteristics of Atmospheric Circulation and Low Temperature Disturbance of Long-Term Catastrophic Freezing Weather in Guangxi

作　　者：王艳兰[1] 伍静[1] 唐桥义[1] 唐熠[1] 黎微微 WANG Yanlan;WU Jing;TANG Qiaoyi;TANG Yi;LI Weiwei(Guilin Meteorological Bureau,Guangxi,Guilin 541001)

机构地区：[1]广西桂林市气象局,桂林541001

出　　处：《气象科技》2022年第1期75-84,共10页Meteorological Science and Technology

基　　金：2019年中国气局预报员专项项目(CMAYBY2019-087);区局项目(桂气科2017Z06、2020M07、2021M05)共同资助。

摘　　要：利用常规观测和NCEP再分析资料,分析2008—2019年广西低温雨雪冰冻过程(简称低温过程)。结果表明:广西低温过程分为稳定阻塞、减弱阻塞、两槽一脊及多波动型,稳定阻塞型持续8~15 d,其余类型小于等于6 d。稳定阻塞型中高纬补充的冷空气及低纬输送的水汽是广西低温过程持续的重要因素,700 hPa西南气流提供水汽和热量,有利于融化层及冻雨形成,低层宽广的温度锋区及大的平均锋生函数利于低温过程持续。稳定阻塞型具有云顶温度-10~0℃、低层冷垫≤-7℃、中层融化层≥8℃的冻雨温度层结,两槽一脊型则为云顶温度-20~-10℃、无融化层、低层冷垫达-10℃的纯雪温度层结。稳定阻塞型低温扰动路径为东路加西路,其他型为东路,前期强低温扰动具有指示意义。东路加西路低温扰动先从贝湖南移,再从巴湖东移补充;巴湖低温扰动不断补充对长周期过程有重要作用。由前期低温扰动位置及环流型可对低温过程路径及持续时间作初步判断。Using conventional observation and NCEP reanalysis data,the catastrophic freezing weather process(low-temperature process for short)in Guangxi during 2008-2019 are analyzed.The results show that the low-temperature process in Guangxi was divided into stable blocking,weakened blocking,trough-ridge,and fluctuation.The stable blocking process lasted 8 to 15 days,and the rest type was 6 days or less.The cold air constantly supplied from high latitudes and the water vapour transported from low latitudes were two essential factors for continuing the low-temperature process in Guangxi.Water vapour and heat provided by southwest wind at 700 hPa were conducive to melting layer formation and freezing rain.The wide temperature front area and high value of average frontogenetic function were favourable for the long time low-temperature process.There was freezing rain temperature stratification with cloud top temperature of-10 to 0℃,low layer cold pad≤-7℃,middle layer melting layer≥8℃in stable blocking and pure snow temperature stratification with cloud top temperature of-20 to-10℃,no melting layer,and low layer cold pad temperature of-10℃in trough-ridge.Path of Low-temperature disturbance(LTD)in stable blocking was“east+west”path,and those of other types were east path.The previous strong LTD had instructive significance.LTD first moved southward from Lake Baikal to the north of Guangxi,then eastward from Lake Balkhash along the plateau’s north in the“east+west”path process.The continuous supplement of LTD in the area of 75°E near Lake Balkhash played an important role.Based on the location of the previous LTD and the circulation,the path and duration of the low-temperature process could be judged preliminarily.

关 键 词：低温雨雪冰冻 环流特征 温度层结 锋生函数 低温扰动 

分 类 号：P458[天文地球—大气科学及气象学]