桂北地区强冰雹的雷达临近预警指标分析  

Radar Early Warning Index Analysis of Severe Hail in North of Guangxi

作　　者：覃靖 潘海 刘蕾 李亚琴 袁马强 苏小玲 

机构地区：[1]广西壮族自治区柳州市气象局,广西柳州545001

出　　处：《灾害学》2017年第2期159-164,共6页Journal of Catastrophology

基　　金：柳州市气象局自立项目(柳气科201602)

摘　　要：利用柳州多普勒雷达(SB)产品和冰雹灾情资料,采用统计的方法,对2008年至2016年5月柳州及相邻地区20块冰雹云进行分析,归纳出强冰雹云的雷达回波特征:低层反射率因子出现钩状回波、人字形回波或V型缺口,中层出现有界弱回波区(BWER)或宽阔的弱回波区(WER),高层强回波悬垂;径向速度图上伴随中等强度以上中气旋。并得出桂北地区强冰雹的雷达临近预警指标:出现三体散射特征,0℃层高度在3.0~4.8km;风暴顶高≥10 km、最大反射率因子高度≥7 km;50 d BZ强回波伸展高度≥9.5 km或强回波在负温区的厚度(H_(50dBZ)-H_(0℃))≥5 km,在冰化区的厚度(H_(50dBZ)-H_(-20℃))≥1.5 km;-10℃、-20℃和-30℃高度层的强回波面积分别达到35 km^2、15 km^2、5 km^2或这三个高度层的强回波面积的平均值达到20 km^2;垂直累积液态水含量VIL≥60 kg·m^(-2)、VIL密度≥5.8 g·m^(-3)。Using Doppler weather radar data and hail disaster data, based on statistic method, the features of 20 hailstorms over Liuzhou and adjacent areas, Guangxi province from 2008 to 2016 are analyzed. The radar echo features of severe hailstorms are summed： the low level reflectivity shows a hook echo and herringbone echo and V- notch, as well as bounded weak echo area or wide weak echo area at the middle level and strong overhanging struc- ture, at the same time, moderate or strong mesocyclones appear at the corresponding radial velocity. Some radar now-casting indicators of severe hail are found which are suitable for the north of Guangxi area： Three-body scatter- ing occurs and the height of 0 ℃ layer at 3.0 - 4. 8 km. Storm top height ≥ 10 km and maximum reflectivity height ≥7 km. 50 dBZ strong echo height ≥9.5 km or H50aBz-H0℃ i〉5 km, H50dBz-H 20℃ ≥1. 5 kin. The 50 dBZ rang reaches 35 km2onthe -10 ℃ layer and 15 km2 onthe -20 ℃ layer and5 km2onthe -30 ℃ layer or the average rang of 50 dBZ on these three layers reaches 20 km2. Vertically integrated liquid value≥60 kg m-2 and density of VIL≥5.8 g m-3.

关 键 词：强冰雹 雷达 临近预警 桂北地区 

分 类 号：X43[环境科学与工程—灾害防治] P406[天文地球—大气科学及气象学]