Preliminary analysis of relationship between cloud-to-ground flash activity and radar parameters of a thunderstorm in Hainan Island

Hainan Island is located in the tropics. Both local thunderstorms (LT) and systemic thunderstorms (ST) coming from the sea are common in April to October over island. On June 10 in 2013, LT and ST met over Hainan Island and merged into one, which gradually developed into a squall line. The relationships between radar echo characteristic parameters, i.e. Combined Reflectivity (CR), Vertical integrated Liquid Water Contents (VLWC), Cloud Top Heights (CTH), 35, 40, 45, and 50 dBZ Echo Top Heights (ETH), and cloud-to-ground (CG) lightning stroke rates of this case were analyzed, using Doppler weather radar data and CG lightning location data. With the development of LT, CG lightning stroke rates increase (decrease) with the increase (decrease) of the radar parameters. CG lightning occurs mostly in the development and mature stage of LT. However, CG lightning activity in ST is just reverse, which generally happens when the radar parameters reduce. Regardless of LT, ST or squall line, the maximum values of CR, VLWC, and CTH are at least 50 dBZ, 15 kg·m^-2, and 12 km, respectively, CG lightning is likely to occur. 35 dBZ ETH reached 10 km is also a good index of lightning occurrence.