兰州周边地闪分布特征  

Lightning Distribution Characteristics around Lanzhou

作　　者：李照荣[1] 陈添宇[2] 康凤琴[2] 庞朝云[1] 杨增梓[1] 丁瑞津[1] 安林 

机构地区：[1]甘肃省人工影响天气办公室,甘肃兰州730020 [2]兰州干旱气象研究所,甘肃兰州730020 [3]兰州市气象局,甘肃兰州730020

出　　处：《干旱气象》2004年第2期45-51,共7页Journal of Arid Meteorology

基　　金：科技部社会公益性研究课题"西北地区防雹消雹技术"(2002DIB10046);"闪电定位仪应用研究"项目(2004人影-1)共同资助。

摘　　要：利用2000年和2002年设在兰州的闪电定位仪资料,分析了兰州周边地区地闪的日频次变化、强度谱分布和累计百分数、日均月变化、闪电密度、极性等特征,并与山东地区的分布做了比较。结果表明,兰州周边地区的云—地闪电中负闪占绝大多数,正闪的平均强度大于负闪,正负闪的比值在午后至次日凌晨大于其均值;总地闪和负闪的日变化呈典型的双峰变化,正闪的双峰特征不明显;兰州西南偏南的渭源和陇西县是闪电频发的中心地带,闪电空间分布中心与冰雹发生源地和影响区对应一致;闪电多发区与地形和气候背景有很大关系。By using the lightning data in 2000 and 2002 around Lanzhou,lightning characteristics such as daily variation, spatial density,intensity and polarity of lightning are analyzed and also compared with those in Shandong province.The results indicate that major cloud-to-ground (CG) flashes of lightning are negative. The mean intensity of positive flashes is stronger than that of negative flashes and their ratio is over average during 12:00 to 00:00.Daily variety of the CG and negative flashes is bimodal undulance, other than positive flashes unimodal. The biggest flashes frequency center locates in Weiyuan and Longxi county, and accord with the location of hail source area and hail affecting zone. Furthermore,the spatial distribution of lightning is closely related to the topography and underlying surface and synoptic climatic background.

关 键 词：云一地闪电 分布特征 冰雹 

分 类 号：P427.3[天文地球—大气科学及气象学]