南京地区闪电活动对气溶胶浓度变化的响应

Response of Lightning Activity to Aerosol Concentration Change in Nanjing Area

基于闪电卫星和地面观测资料、气溶胶光学厚度(aerosol optical depth,简称AOD)卫星观测资料,对南京地区闪电活动对气溶胶浓度变化的响应进行了分析。结果表明,夏季年平均闪电密度与夏季年平均AOD呈明显负相关(R=-0.634),与此同时,地面气温、对流有效位能(CAPE,convective available potential energy)及雷暴日与AOD均呈显著负相关(R=-0.748,-0.741,-0.744),表明南京地区,气溶胶可能通过辐射效应,致使地面温度降低,对流活动减弱,从而使得闪电活动降低。除此之外,南京地区夏季年平均正地闪比例(正地闪数占总地闪数的比例)随AOD呈一定的上升趋势,说明气溶胶可通过微物理效应,改变雷暴云中电荷结构分布,从而使得正地闪的产生概率增大。

Based on lightning satellite and ground observation data, aerosol optical depth （AOD） satellite observation data, the response of lightning activities to aerosol concentration change in Nanjing area is analyzed. The results indicate that the radiative effect of aerosol may be one of the main reasons for the decrease of the lightning flash density in a long period, and the aerosol microphysical effect may plays a major role in the increase of the percent of ＋CG flashes （P＋CG）. The dependence of surface temperature, CAPE and thunderstorm days on AOD （R=-0.748, -0.741, -0.744）, and the negative correlation （R=-0.634） between lightning flash density and AOD may lend support for the radiative effect of aerosol on lightning. In addition, elevated aerosols may change the charge distribution in thundercloud, hence enhancing the positive cloud-to-ground lightning （＋CG） activity, as P＋CG is positively correlated with AOD.