我国地闪活动和降水关系的区域差异

利用我国部分地区2005年的地闪定位资料和气象台站雨量观测资料,由南向北选取我国四个不同气候带区域(区域1～4),分析了这些区域的地闪活动与降水的相关关系。结果表明,由南向北及气候特征由潮湿趋于干旱的区域的地闪活动和降水相关性增强。闪电活动与有闪电降水(即对应闪电的降水)日变化的线性相关系数在由南向北的区域分别为0.56、0.46、0.56、0.80,旬变化的线性相关系数分别为0.73、0.86、0.89、0.92,月变化的线性相关系数分别为0.74、0.88、0.965、0.99;较干旱的区域3和区域4的地闪活动与所有降水的时间序列有较强的相关性,其线性相关系数日变化分别为0.31、0.41,旬变化分别为0.84,0.52,月变化分别为0.93、0.80;地闪与降水的空间线性关系相对复杂,但也表现出由南向北和气候趋于干旱对应关系增强的特征,区域4的闪电和降水相关性达到0.54。分析区域中较干旱地区的雷暴活动产生机制(主要受热力抬升作用)相比潮湿地区(既受热力抬升作用,又受大尺度系统相互作用)更为单一,这可能是干旱地区的闪电活动与降水有较好相关的重要原因。

REGIONAL DIFFERENCES OF RELATIONSHIP BETWEEN CLOUD-TOGROUND LIGHTNING AND PRECIPITATION IN CHINA

Cloud-to-ground(CG) lightning data observed by ADTD lightning location network and precipitation data observed by meteorological observation stations located in four regions of different climatic belts of China are used to analyze the relationship between CG lightning and rainfall.It was found that the linear correlation between CG lightning and rainfall increases with the latitude changing from low to high and the climate changing from humid to arid.The linear correlation coefficients between the CG lightning frequencies and the precipitation related to lightning activity in the four regions changing from low to high latitudes are 0.56,0.46,0.56 and 0.80 for daily variation,0.73,0.86,0.89 and 0.92 for ten-day variation,and 0.74,0.88,0.965 and 0.99 for monthly variation,respectively.The CG lightning and all the precipitation in region 3 and region 4-more arid than the other two regions-also have good relationships.The linear correlation coefficients between them in region 3 and region 4 are 0.31 and 0.41 for daily variation,0.84 and 0.52 for ten-day variation and 0.93 and 0.80 for monthly variation,respectively.The spatial relationships between CG lightning and precipitation,although being complicated,also strengthen with the changes of the latitude from low to high and the climate from humid to arid,with the related coefficient in region 4 being 0.54.Compared to the lightning-producing mechanism in humid areas(resulting from both thermodynamic uplifting and large-scale interactions),that of arid areas(resulting from thermodynamic uplifting) is more unique,which is much attributed to better correlations between lightning and precipitation in arid areas.