摘要
利用2009年夏季在大兴安岭林区开展的雷暴及闪电的多站GPS同步观测资料,详细分析了该地区的地闪放电特征。通过对464次地闪资料的分析,发现具有单次回击的地闪所占的比例高达69%,且正地闪比例较高,达到了22%。对连续电流的统计表明,约有27%的地闪伴随有连续电流过程且长连续电流过程主要出现在具有单次回击的负地闪中,其平均持续时间为127.4ms。进一步分析发现连续电流的持续时间与引发连续电流的回击电场变化及其回击之前击间间隔具有较好的对应关系:当引发连续电流回击电场变化及其之前击间间隔越小,连续电流持续时间越长。对两次正地闪的拟合研究表明,二者释放的电荷量相当可观,分别为38C、36C,海拔高度分别为7.6km、7.0km。
By using multi-station observations on thunderstorm in Da Hinggan Ling forest region which was conducted in the summer of 2009,the characteristics of cloud-to-ground（CG） lightning discharges were analyzed.The results show that 69% of 464 CG lightning flashes were single-stroke CG lightning flashes and the percent of positive CG lightning flashes was up to 22%.Statistics show that 27% of CG lightning flashes were followed by continuing current and single-stroke CG lightning flashes were usually followed by long continuing current.The mean duration of long continuing current is 127.4 milliseconds.Furthermore,results show that there is corresponding relationship among the duration of continuing current,the inter-stroke interval just preceding the interval containing continuing current,and the electric field change of stroke initiating continuing current： the smaller the inter-stroke interval just preceding the interval containing continuing current and the electric field change of stroke initiating continuing current,the longer the duration of continuing current.In addition,two positive CG lightning flashes have been calculated by using the nonlinear least-square method.The results show that the two positive CG lightning flashes occurred at 7.6 km and 7.0 km above mean sea level,respectively.And 38 coulombs quantity of electricity and 36 coulombs quantity of electricity have been neutralized during discharge process for these two flashes,respectively.
出处
《大气科学》
CSCD
北大核心
2011年第1期147-156,共10页
Chinese Journal of Atmospheric Sciences
基金
林业公益性行业科研专项经费课题(200704027-1)
国家自然科学基金资助项目40930949
中国科学院"百人计划"专项经费
关键词
大兴安岭林区
雷暴
地闪
连续电流
Da Hinggan Ling forest region
thunderstorm
CG flash
continuing current
