山东半岛一次强飑线过程地闪与雷达回波关系的研究  

Study of the Relationship between Cloud-to-Ground Lightning and Radar Echo of a Severe Squall Line in Shandong Peninsula

作　　者：吴学珂[1] 袁铁[1] 刘冬霞[2] 冯桂力[3] 

机构地区：[1]兰州大学大气科学学院/半干旱气候变化教育部重点实验室,甘肃兰州730000 [2]中国科学院大气物理研究所中层大气与全球环境探测重点实验室(LAGEO),北京100029 [3]山东省气象科学研究所,山东济南250031

出　　处：《高原气象》2013年第2期530-540,共11页Plateau Meteorology

基　　金：国家自然科学基金项目(40905008;40930949);教育部"春晖计划"(Z2008-1-62016)共同资助

摘　　要：利用山东省气象局地闪定位资料和青岛多普勒雷达资料,分析了2007年7月31日发生在山东半岛一次强飑线过程的地闪活动演变特征以及地闪活动与雷达回波特征的关系。结果表明,此次过程中地闪异常活跃,最大频数达到1 212fl.(10min)-1,但正地闪仅有15次。在飑线系统快速发展阶段,地闪频数出现了两次"跃增"现象,地闪频数随时间的增加呈"阶梯状"发展特征。地闪主要集中发生在6km高度上雷达回波≥35dBZ的区域,地闪频数与45dBZ以上强回波面积的相关系数达到0.89,但也有少量地闪零星分布在弱回波区域。地闪频数与45dBZ回波顶高的相关性要好于与35dBZ和50dBZ回波顶高的关系,二者之间的相关系数为0.71。为了定量分析对流强度与地闪频数之间的关系,定义了8个对流强度指数,其中0℃层以上所有强回波的反射率因子值之和与0℃层以上所有强回波的反射率因子值与所在高度的乘积之和以及地闪频数的关系非常稳定。对比分析不同强度的对流系统,发现不同雷暴天气过程中的对流强度与地闪频数的关系明显不同,即对流越强,相应的对流强度与地闪频数的相关关系也越好。另外,在飑线系统的发展演变过程中,地闪频数与0℃层以上和7～11km高度的冰相降水含量也存在着非常密切的关系,相关系数均在0.8以上。The evolution characteristics of cloud-to-ground （CG） lightning activity and its relationship with radar echo during a severe squall line in Shandong Peninsula on July 31, 2007 have been studied using the CG lightning location data from Shandong Meteorological Bureau and the Qingdao Doppler radar base data. The results show that CG lightning was quite active during this squall line, the maximum CG flash frequency was up to 1 212 fl · （10 min）-1 , but there were only 15 positive CG flashes during it＇s lifetime. During the rapid developing stage of the squall line, it can be seen that there were two steep increase periods of flash frequency, and there was a step-shaped trend in CG flash evolution. Most of CG flashes occurred in the regions with radar reflectivity ≥35 dBZ at 6 km altitude. The correlation coefficient between CG flash frequency and intense echo area （≥45 dBZ） was 0.89, but still there were a few CG flashes scattering in the regions with weaker echo. Further study indicates that there was a strong positive correlation between convective intensity and CG flash frequency. Comparing with 35 dBZ and 50 dBZ, the relationship between CG flash frequency and the top height of 45 dBZ echo was better, and their correlation coefficient was 0.71. In order to quantitatively analyze the relationship between convective intensity and flash frequency, eight convective intensity indices have been developed. Among these indices, both the total of intense radar reflectivities （≥35 dBZ） above 0 ℃ level and the total of the products of intense radar reflectivities （≥35 dBZ） above 0 ℃ level and their heights appeared steady relations with CG flash frequency. Comparing with another weaker convective system, it was found that the stronger the convection, the better the correlation between convective intensity and CG flash frequency. In addition, both ice precipitation content above 0 ℃ level and that between 7-11 km were also closely related to CG flash frequency, both correlation coeffici

关 键 词：飑线 地闪 雷达回波 冰相降水含量 

分 类 号：P427.32[天文地球—大气科学及气象学]