北京一次极端雨雪天气异常诊断分析  

Abnormal Diagnosis and Analysis of an Extreme Rain and Snow Weather in Beijing

作　　者：翟亮[1] 王林[2] 郭金兰[1] 雷蕾[1] 杜佳[1] 张迎新[1] ZHAI Liang;WANG Lin;GUO Jinlan;LEI Lei;DU Jia;ZHANG Yingxin(Beijing Weather Forecast Center,Beijing 100089,China;Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China)

机构地区：[1]北京市气象台,北京100089 [2]中国科学院大气物理研究所,北京100029

出　　处：《沙漠与绿洲气象》2022年第4期9-13,共5页Desert and Oasis Meteorology

基　　金：北京市自然科学基金项目(8214058);中国气象局预报员专项项目(CMAYBY2020-002);北京市气象局科技项目(BMBKJ202001028、BMBKJ202001006)。

摘　　要：2020年2月13-14日北京地区出现一次极端雨雪天气过程,利用EC再分析数据、风廓线雷达、气候资料等,采用诊断分析、风廓线产品反演、气候异常分析等方法,对这次伴有复杂相态转换、对流、累计降水量破历史同期极值的极端雨雪天气过程进行分析和异常诊断,结果表明:(1)大尺度低涡、高/低空急流、锋面等天气系统为降水提供良好的背景条件。(2)河北中部的中尺度涡旋,是这次极端雨雪天气的重要成因之一。(3)对流活动的参与提高了降水效率,致使过程累计降水量进一步增大。(4)850 h Pa切变线北侧强盛的偏东气流,在动力抬升、水汽输送及辐合中发挥重要作用。(5)-8~-20℃层云冰含量低,且0℃层高度>700 m是造成北京平原地区相态转换时间延迟的直接原因。(6)边界层回流冷空气由平原东部进入北京,是雨雪相态转换由东向西发生的根本原因。(7)极端的水汽通量辐合异常,是此次天气过程累计雨量突破同期历史极值的重要原因之一。Based on EC reanalysis data,an extreme rain and snow weather in Beijing on 13-14 February,2020 was analyzed.The results show that:(1)Large scale vortex,front,etc provided good background conditions for precipitation.(2)The mesoscale vortex in the central part of Hebei province was an important cause of extreme weather.(3)Convection improved precipitation efficiency,which led to further increase of accumulated precipitation.(4)The strong easterly flow on the north side of 850 hPa shear played an important role in dynamic uplift,water vapor transport and convergence.(5)The low content of cloud ice in-8~-20℃layer and the height of 0℃ layer over 700 m were the direct reasons for the delay of phase transition in Beijing plain.(6)The boundary layer backflow was the fundamental cause of the phase transition from east to west.(7)The convergence anomaly of water vapor flux directly led to rainfall extremes.

关 键 词：极端雨雪 中尺度涡旋 云冰含量 0℃层高度 气候异常 

分 类 号：P458.121[天文地球—大气科学及气象学]