摘要
利用陕西过去54年96个测站降雪资料、常规高空地面气象资料及NCEP再分析资料,分析了陕西省1955—2008年连阴雪天气气候特征和时空分布,对两次全省性强连阴雪天气过程的环流形势及动力、热力特征进行了对比分析,并与秋季连阴雨比较,结果表明:陕西54年间连阴雪天气强度及时空分布差异明显,2008年1月连阴雪天气为1955年以来陕西省最强连阴雪天气,1989年次之。强连阴雪天气发生时长波系统稳定少变,高空锋区、东西路冷空气、偏强偏北的副热带高压、稳定的南支槽是两次持续降雪的主要影响系统。200hPa西风急流演变对连阴雪天气发生、发展有指示意义。两次连阴雪天气期间水汽输送主要存在于对流层低层,副热带高压外围水汽输送带和偏东气流为主要水汽来源。连阴雪天气期间陕西省处于能量锋锋区中,不同于秋季连阴雨天气。强降雪天气过程发生与陕西夏、秋季强降水有相似的热力和动力学特点,但强度偏弱。提出了陕西冬季连阴雪天气预报着眼点。
Using the snow data of 96 stations in Shaanxi Province,conventional ground and sounding meteorological data,and NCEP reanalysis data,the consecutive cloudy-snow climatic characterstic and its temporal-spatial distributions in Shaanxi Province during 1955／_2008 are analyzed,especially two severe snowfall processes,as well as the comparison with consecutive autumn rainfall.The results are as follows.Firstly,the intensity and temporal-spatial distributions for consecutive cloudy-snow weather are very different in recent 54 years.Secondly,1989 and 2008 are the two strongest snowfall process years throughout-Shaanxi Province since 1955.Circulation characterstics are the stable atmospheric circulation-and long wave system,upper-layer frontal zone,transmeridianal-cold air,stronger eastward subtropical high and-stable active south branch trough.Thirdly,the evolution of westerly jet on 200 hPa can indicate the occurrence-of continuous cloudy-snow and its evolution.The water vapor transport is from the outside of subtropical high and eastward flow at lower level troposphere.During the consecutive snowfall,energy frontal zone lies in Shaanxi Province,where is different with continuous autumn rain.Heavy snowfall process is as same thermal and dynamic characters as summer-autumn precipitation,but with weaker intensity.According to above conclusions,new forecast point of consecutive-snowfall process in winter are given and offer useful reference opinions to forecast the local snow-ice disasters.
出处
《高原气象》
CSCD
北大核心
2010年第4期947-956,共10页
Plateau Meteorology
基金
陕西省气象局研究型业务重点科研项目(2009M-3)资助
关键词
陕西省
连阴雪天气
环流特征
西风急流
水汽输送
强降雪
预报着眼点
Shaanxi Province
Consecutive cloudy-snow weather
Circulation characteristic
Westerly jet
Water vapor transport
Heavy snowfall
Forecast precursor
