甘肃中部地区短时强降水与闪电关系初步分析

Analysis on Relationship Between Short-term Strong Rainfall and Lightning in Middle Gansu Province

利用2008~2013年甘肃中部地区布网的LD-Ⅱ闪电定位系统观测到的地闪定位资料及区域自动站小时降水资料,将闪电单位资料处理成时间分辨率为1 h、空间分辨率为0.1°×0.1°（经纬度,面积约为100 km2）的空间网格闪电密度数据,并与该区域中的区域站降水量作对比分析。结果表明：正闪比例与降水强度有较好的正相关;闪电密度的时空分布与强降水时空分布有较好的一致性,但在时间上闪电密度的变化提前于强降水落区的变化;闪电密度〉9次/100 km2·h和〉5次/100 km2·h阈值分别对〉20 mm/h和10 mm/h短时强降水预警,其命中率很高。

Based on the CG location data and hourly precipitation data from automatic stations in central part of Gansu Province from2008 to 2013,the relationship between short- time strong precipitation and lightning was analyzed. Lightning data were processed into spatial grid lightning density data with one hour temporal resolution and 0. 1° × 0. 1° spatial resolution,which were compared with precipitation data from regional stations. Results show that the proportion of positive lightning had a better positive correlation with rainfall intensity,and the distribution of lightning density was coincident relatively with the strong rainfall region. The changes of lightning density were always ahead of the changes of strong rainfall area. Applying the thresholds of lightning density greater than 9 times /100 km2·h and 5 times /100 km2·h could forecast the short heavy rainfall more than 20 mm/h and 10 mm/h better,respectively.