Long-term trends of lightning and thunderstorms and the potential roles of aerosols in China

This study analyzes multi-years of the Tropical Rainfall Measuring Mission (TRMM) satellite data, surface lightning, thunderstorms and visibility data to study the trends and relationships of aerosols and thunderstorms in Southeast China. The TRMM data used are from the lightning imager sensor (LIS) and precipitation radar (PR). Surface data are human-observed thunderstorm occurrence and visibility for the period of 1990-2012 at 70 plain stations and 4 mountain stations. We analyzed data for different regions dominated by different types of aerosols and found distinct relations. In south and southeast zchina, thunderstorm, lightning and radar echo top-heights have all increased significantly during the time period under study, while regional mean visibility has decreased greatly at the plain stations. The daily rainfall amount with thunders has increased significantly, but rainfall without thunders has no trend during this period. At the four mountain weather stations of elevation greater than 1100 m, however, there has been no trend in the number of thunderstorm days. Yet, the ratio of the number of lightning per rainy day between plain and mountain stations has increased significantly. The distinct trends between the plain and mountain station may originate from large differences in aerosol concentration between plain and mountain regions. The accumulation of pollution aerosols in the plain region is likely to invigorate thunderstorms, whereas no or less impact on intense convection is found over regions of high altitude. In central west China, the opposite trends were observed for thunderstorms and lightning, presumably because of more dominant soot aerosols whose radiative and thermodynamic effects may a have overwhelming of suppressing the convection and associated severe weather event.