区域闪电活动对地面相对湿度的响应  

Regional responses of lightning activities to relative humidity of the surface

作　　者：熊亚军[1] 郄秀书[1] 周筠珺[1] 袁铁[1] 张廷龙[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所雷电与雷暴实验室,兰州730000

出　　处：《地球物理学报》2006年第2期367-374,共8页Chinese Journal of Geophysics

基　　金：国家杰出青年科学基金项目(40325013);国家自然科学基金"十五"重点项目(40135010)资助.

摘　　要：全球闪电活动表现出明显的地域差异,温度和湿度是造成这种差异的基本气象因素.本文利用美国全球水资源和气候中心提供的1995～2002年全球闪电资料和NCEP气象再分析资料,研究了区域闪电密度对地面相对湿度(RH)的响应.发现在平均相对湿度RH<72%的经度带里闪电密度与RH呈正相关.而在RH>73%的经度带里,闪电密度与RH呈负相关;在RH>74%的赤道地区闪电活动与RH呈负相关,而在RH<72%的中高纬地区闪电密度与RH呈正相关.得到结论:当地面相对湿度过大时,相对湿度的增加不利于闪电活动的发生;而当相对湿度较小时,相对湿度的增加有利于闪电活动的发生.地面相对湿度的临界值域约为72%～74%.此结论在不同经、纬度的几个典型区域均得到了验证,并探讨了过大的相对湿度抑制闪电活动发生的可能原因.Global flash activity shows great contrast in different regions. Temperature and humidity are the essential meteorological factors that result in this difference. The regional response of lightning activities to the relative humidity （Rн ） is examined at different longitudes and latitudes using lightning data from satellite and NCEP metrological observations （from 1995 to 2002）. The result indicates that lightning activities respond positively to Rн within longitudinal belts where Rн is more than 74% and respond negatively to the regions where Rн is less than 72%. A similar response is found in latitudinal belts. It can be concluded that higher relative humidity results in more lighting activities at dry regions and less lighting activities at wet regions. The watershed of relative humidity is about 72 % - 74%. Six typical regions have been chosen to validate above results and an agreement has been found.

关 键 词：闪电密度 相对湿度(Rн) 云底高度 区域差异 

分 类 号：P427[天文地球—大气科学及气象学]