Case Studies of Sprite-producing and Non-sprite-producing Summer Thunderstorms

Three summer thunderstorms in the eastern region of China were analyzed in detail using multiple data, including Doppler radar, lightning location network, TRMM (Tropical Rainfall Measuring Mission), MTSAT (Multi-Function Transport Satellite) images, NCEP (National Centers for Environmental Prediction) Reanalysis, and radiosonde. Two of the three storms were sprite-producing and the other was non-sprite-producing. The two sprite-producing storms occurred on 12 August and 2728 July 2007, producing 16 and one sprite, respectively. The non-sprite-producing storm occurred on 2930 July 2007. The major objective of the study was to try to find possible differences between sprite-producing and non-sprite producing storms using the multiple datasets. The results showed that the convection in the 12 August storm was the strongest compared with the other storms, and it produced the largest number of sprites. Precipitation ice, cloud ice and cloud water content in the convective regions in the 12 August storm were larger than in the other two storms, but the opposite was true in the weak convective regions. The storm microphysical properties along lines through parent CG (cloud-to-ground lightning) locations showed no special characteristics related to sprites. The flash rate evolution in the 12 August storm provided additional confirmation that major sprite activity coincides with a rapid decrease in the negative CG flash rate. However, the evolution curve of the CG flash rate was erratic in the sprite-producing storm on 2728 July, which was significantly different from that in the 12 August storm. The average positive CG peak current in sprite-producing storms was larger than that in the non-sprite-producing one.