Lightning flash density in relation to aerosol over Nanjing (China)

Abstract

Time series data of lightning flash density, aerosol optical depth (AOD), surface temperature, convective available potential energy (CAPE) and thunderstorm days for 10years (2002–2011), cloud-to-ground lightning (CG), and AOD of 5years for summer season, i.e., June, July, and August over Nanjing, China, have been analyzed, to investigate the impact of aerosols on lightning. The results indicate that the radiative effect of aerosol may be one of the main reason for the decrease of the lightning flash density in a long period, while the aerosol microphysical effect may be 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.