Thunderstorm Structure and Lightning Properties in South China and over the South China Sea: A Comparative Study

Using lightning data from the Lightning Imaging Sensor onboard the Tropical Rainfall Measurement Mission satellite, together with cloud and precipitation property data extracted from the Radar Precipitation Feature dataset, this study investigated the statistical characteristics of thunderstorm structure and lightning properties over land (South China) and the South China Sea (SCS) during 1998–2014. The objective was to compare thunderstorm structural differences and explore the impact of thunderstorm structure on lightning properties between land and transitional water areas to the deep ocean. The results indicate that the lightning activity in South China is notably more intense than that over the SCS, with the average frequency and density of lightning in South China approximately doubling the values of those over the SCS. Although the mean flash duration is similar in both regions, lightning over the SCS exhibits larger average values for flash length, footprint, and radiance. Additionally, the horizontal scale and the verti-cal extension of thunderstorms over the SCS are substantially larger than those in South China, i.e., the thunderstorm precipitation area and the 20-dBZ area over the SCS are twice the size of those in South China, and the average 20-dBZ echo top height is 1.25 km higher over the SCS. Nevertheless, thunderstorms in South China develop more intensely, with elevated heights of the intense convective core (40-dBZ echo) compared with those thunderstorms over the SCS. The mean values of the 37-GHz minimum polarization-corrected temperature (PCT) are comparable between the two regions, but the mean value of the 85-GHz PCT is lower over the SCS, suggesting a higher concentration of small ice particles in SCS thunderstorms. Finally, a conceptual diagram that highlights the differences in thunderstorm structure and lightning flash properties between South China and the SCS is proposed. Compared with previous studies, this study has elucidated the distinct characteristics of oceanic lightning over the SCS, and highlighted the gradual transition of thunderstorm scale and lightning properties from land, to the SCS, and finally to the deep ocean area of the Northwest Pacific Ocean.