一次高空急流背景下江西暴雪过程分析  

Analysis of a Snowstorm Influenced by Upper Troposphere Jet Stream in Jiangxi Province

作　　者：周芳 王晓东 毛连海 ZHOU Fang;WANG Xiaodong;MAO Lianhai(Jiangxi Meteorological Observatory,Nanchang 330096,China;Jiangxi Meteorological Information Centre,Nanchang 330096,China)

机构地区：[1]江西省气象台,江西南昌330096 [2]江西省气象信息中心,江西南昌330096

出　　处：《沙漠与绿洲气象》2021年第1期36-45,共10页Desert and Oasis Meteorology

基　　金：中国气象局气象预报业务关键技术发展专项子项目(YBGJXM(2018)03-09)。

摘　　要：利用常规观测、人工降雪加密观测资料以及GFS 0.25°×0.25°再分析资料,基于配料法(Ingredients-based Methodology,IM),对2018年12月30日江西北部暴雪过程及降雪强度变化进行了分析。结果表明:高空槽、中低层切变线和高空急流、低空西南和东南急流及地面冷高压共同造成了暴雪过程,暴雪发生在200 hPa急流轴以南,500 hPa高空槽以东,700 hPa急流轴以北。降雪强度变化主要与高、低空急流有关:高空急流通过正涡度平流与低空急流产生作用,并通过次级环流加强上升运动,从而影响降雪强度变化。4个构成要素造成暴雪:切变线上辐合及高、低空急流的耦合造成强烈的上升运动,西南急流输送充足的水汽,适宜的温度层结及较高的降雪效率。积雪深度与降雪效率、下垫面温度密切相关。500 hPa相对湿度和温度可以作为精细化预报降雪量、积雪深度的指标。The snowstorm in south China on 30 December 2018 was analyzed using the GFS reanalysis data and meteorological observing stations data by ingredients-based methodology.The results showed that:(1)The snowstorm was caused by cooperation of high trough,low level shear,the jet stream in upper and low level,and surface cold air"cushion".The snowstorm occured at the south of jet stream on 200 hPa,the north of the jet stream on 700 hPa,the west of trough on 500 hPa.(2)Upper and lower troposphere jet steam greatly affect the snowstorm.(3)The snowstorm depended on four ingredients:strong vertical velocity by low level shear and the convergence of upper and lower troposphere jet steam,plenty vapor transfered by lower troposphere jet steam,optimal precipitation efficiency(-15℃,90%on 500 hPa)and air temperature stratification.(4)The relative humidity and temperature in 500 hPa could be used to forecast the depth of snow after air temperature at 2 m and surface temperature decreased below 0℃.

关 键 词：暴雪 配料法 急流 降雪效率 积雪深度 

分 类 号：P458.121.1[天文地球—大气科学及气象学]