The Statistical Characteristics of Convective Cells during the Asian Summer Monsoon Season in East China

This study examines the temporal and spatial characteristics of convective cells during the Asian summer monsoon season in East China using 5 years of operational Doppler radar in the region. The properties of convective cells, including the storm lifetime, storm top, max reflectivity ,vertical integrated liquid water (VIL) and lightning flash rate are derived from the storm cell identification and tracking (SCIT) products. Results show the convective cells occur most frequently in monsoon active periods especially along Yangtze River, while most frequently lightning flash rates occur in postmonsoon periods. The intensity and lifetime of convection increases from the premonsoon to the monsoon and further to postmonsoon periods, as indicated by the increase of lightning flash rate, storm top and max reflectivity. The enhanced convection in the postmonsoon periods result from the increase of convective available potential energy (CAPE). The convective cells also exhibit a different diurnal cycles at three different periods. The maximum frequency of convective cells during the premonsoon and postmonsoon periods occurs in the early afternoon due to solar heating. In contrast, the diurnal distribution of convection in monsoon active periods occurs most frequently from midnight to early morning. The morning peak may be associated with synoptic-scale forcing.