川西高原中部一次极端暴雪成因分析  

Analysis of an Extreme Snowstorm Weather Process in Central Western Sichuan Plateau

作　　者：孙俊[1,2] 邓国卫 夏炳江 Sun Jun;Deng Guowei;Xia Bingjiang(Sichuan Branch of China Meteorological Administration Training Centre,Chengdu 610071;Heavy Rain and Drought Flood Disasters in Plateau and Basin Key Laboratory,Chengdu 610071;Sichuan Climate Center,Chengdu 610071;Aba Meteorological Service,Maerkang 624000)

机构地区：[1]中国气象局气象干部培训学院四川分院,成都610071 [2]高原与盆地暴雨旱涝灾害四川省重点实验室,成都610071 [3]四川省气候中心,成都610071 [4]四川省阿坝州气象局,马尔康624000

出　　处：《气象科技》2018年第3期584-593,共10页Meteorological Science and Technology

摘　　要：利用0.5°×0.5°的ECWMF再分析资料,常规气象资料以及西南区域数值预报模式模拟等资料,应用天气分析和诊断方法,对2016年2月21日川西高原中东部的极端暴雪天气过程进行系统分析。结果表明:500hPa贝加尔湖横槽旋转南下使得冷空气并入川西高原中部的低槽中,其与西南暖湿气流交汇产生的锋生以及西南急流存在是此次暴雪天气产生的重要原因;随着副高的北进,此次强降雪开始之前有来自于孟加拉湾和南海的两支水汽输送,西南低空急流稳定维持为此次暴雪提供了充足的水汽。MPV2在此次暴雪过程中起到了重要作用;强降雪主要发生在SVD(Slantwise Vorticity Development)强烈发展的时段内,暴雪落区与SVD发展最强烈的区域重合;西南区域数值预报模式提前6h对此次暴雪的形势场和物理量场都做出了较为准确的预报,其中垂直速度和水汽条件预报与实况最吻合,但降水预报的量级较实况偏弱一个量级,强降水落区比强度预报更准确。Based on the observation data and ECWMF 6-hour reanalysis data and the Southwest Regional Numerical Prediction Model,a very severe snowstorm occurred in the middle east of the Western Sichuan Plateau in 21 February 2016 is analyzed and diagnosed.The results show that the snowstorm was mainly related to the southwest jet and the frontogenesis formed in the combination with the cold air and southwest warm and humid airflow.The cold air to the south of the horizontal trough of Baikal was incorporated into the low trough in the central Western Sichuan Plateau.The Bay of Bengal and South China Sea are the sources of the vapor of the snowstorm as the subtropical high moves northward.The heavy snowfall occurred when Slantwise Vorticity Development（SVD）strongly developed and the snowstorm area was the same as the strongest zone for SVD development.The Southwest Regional Numerical Forecast Model made the accurate forecast 6 hours in advance of the snowstorms potential field and physical field.The precipitation forecast was one order of magnitude weaker than the actual precipitation,and the falling zone forecast of the snowstorm was more accurate than its strength forecast.

关 键 词：川西高原暴雪 冷锋 急流 湿位涡 西南区域数值模式 

分 类 号：P458.3[天文地球—大气科学及气象学]