The evolution of cloud-to-ground lightning and radar reflectivity in mesoscale convective systems over Central-Eastern China

By combining geostationary satellite observations, cloud-to-ground (CG) lightning detections, and radar composite reflectivity (CR) mosaics, this study investigates the intensity, evolution, and distribution of CG lightning and CR associated with mesoscale convective systems (MCSs). A total of 551 MCSs are identified in central-eastern China during May–September of 2018–2021 using Fengyun-4 A satellite brightness temperature (BT) data and subsequently matched with CG lightning and CR mosaics. The geographical analysis of CG lightning associated with MCSs reveals that the highest occurrences are most frequent in the transition zone between the Poyang Lake Plain and the surrounding mountains. The proportion of negative-polarity flashes is relatively lower in MCS-related CG lightning than in total CG lightning. An overall negative correlation between BT and the peak current of CG lightning is observed with seasonal variations. The positive correlations detected in May and September may be attributed to the advection of ice particles from convective cores into adjacent stratiform regions, driven by stronger mid-to-upper-level winds. The peak occurrence of CG lightning precedes the maximum MCS extent by 0–2 h. As the MCS develops, the proportion of convective clouds decreases, while that of non-precipitating anvil increases, and the stratiform regions consistently account for 50%–60% of the total MCS extent, dominating throughout its lifespan. The stratiform region is predominantly located in the southern part of the MCS, whereas convective clouds are mainly situated in the northern part, possibly influenced by the Meiyu front.