北京地区冰雹天气特征  

Characteristic Analysis of a Hail Event in Beijing

作　　者：张琳娜[1] 郭锐[1] 何娜[1] 廖晓农[1] 

机构地区：[1]北京市气象台,北京100089

出　　处：《气象科技》2013年第1期114-120,共7页Meteorological Science and Technology

基　　金：北京市气象局预报员创新团队建设计划;2009年公益类行业专项"中尺度对流性天气诊断分析方法研究"(GYHY200906003)资助

摘　　要：利用实况探空资料、北京南郊观象台加密探空资料以及NCEP再分析资料,对2000—2009年北京地区出现的30次冰雹过程进行了详细分析。结果表明:北京地区出现冰雹天气的主要天气类型可以分为3类:东北冷涡型、蒙古低涡型和低槽型。其所占比例分别为东北冷涡12次;蒙古低涡10;低槽8次。冰雹出现的时间集中在午后14:00—18:00。从大尺度形势特征来看,北京冰雹日,从925hPa到500hPa各层均有动力辐合系统,即高空有较深厚的动力系统,并且各层辐合系统当天过境影响北京。蒙古低涡和偏西路径低槽型的流场有如下显著特征:500hPa在内蒙古中部有西北大风速区,风速在20m/s以上;850hPa和700hPa在北京的东南部有偏南大风速区,风速可达12m/s左右。冰雹发生日高空各层湿度并不大,各层温度露点差大都大于5℃,这说明冰雹的发生并不需要较强的湿度条件。对常用物理量参数研究发现,对预报冰雹天气发生有意义的参数及其阈值如下:低空有大的风切变,其中1000/700hPa风切变分布在3m.s-1.km-1左右;850/500hPa风切变分布在2～4m.s-1.km-1之间;500hPa与850hPa温度差为28～35℃;全总指数为40～50℃;0℃层高度为3000～4500m;-20℃层高度为6000～7500m;下沉对流有效位能大于800J.kg-1;深对流指数为20～30;抬升指数小于0。The conventional and intensive-observing radiosonde data from the Beijing South Suburb station and NCEP data are used to analyze 30 cases of hails which happened form 2000 to 2009 in Beijing. The results show that the circulation patterns for hail weather can be classified into three weather types： Northeast cold vortex, Mongolia vortex, and trough; the three types of weather patterns occured 12, 10, and 8 times, respectively; hails often happened from 14：00 to 18： 00. It can be seen from the characteristics of the large-scale weather circulation that there was a dynamic convergence system at each level from 925 hPa to 500 bPa during hail weather. There were deeply dynamic systems passing through Beijing at upper levels. The stream fields of the Mongolia vortex and trough patterns have the typical characteristics that there is a big north-west wind velocity area at 500 hPa between Beijing and Inner Mongolia with speed being 20 m/s or above, and a big south wind velocity area at 700 hPa and 850 hPa with the speed being about 12 m/s in the southeast of Beijing. The humidity condition is not very important to hails because the dew-point deficit at each level was larger than 5℃. The stability parameters are as follow： the temperature difference between 500 hPa and 850 hPa being 28 to 35 ℃, large wind shear at lower levels, DCAPE greater than 800 J. kg-1, LI （Lifted Index） less than 0, DCI （Deep Convective Initiation） between 20 and 30, TT （Total Totals index） between 40 to 50℃, the 0 ℃environmental temperature height between 3000 to 4000 meters 6000 and 7500 meters. --20℃ environmental temperature height being between

关 键 词：冰雹 天气类型 湿度 稳定度指数 

分 类 号：P426.641[天文地球—大气科学及气象学]