Comparative Analysis on Characteristics of Summer Convective Precipitation over Tibetan Plateau and Sichuan Basin
The convective precipitation events that respectively occurred in Tibetan Plateau (TP) and Sichuan Basin are compared and analyzed by using TRMM (Tropical Rainfall Measure Mission) data. The results show that the precipitation system in the TP is mainly convective cloud precipitation and weak rainfall samples are a great many consisting of isolated cloud precipitation cloud clusters. Convective center is scattered, with small precipitation range, uneven rain belt, shallow vertical thickness, fewer precipitation particles and small raindrops. The latent heat which is released at the height of 2-5 km is dominant. The content of ice crystal particles near the ground layer in summer is great. There is a poor correlation between brightness temperature of cloud top and rainfall intensity near surface. The higher the brightness temperature, the larger the number of lightning frequency. In contrast, the precipitation system in Sichuan Basin has more severe precipitation samples, consisting of a main precipitation system and scattered cloud clusters. Convective centers are concentrated, the precipitation scopes are large, rain belt is even, vertical thickness is deep, and raindrops are large. The latent heat is released in the pattern of two peakes and the peak values appear at the heights of 7 km and 16 km. The content of hail particles are much more in the upper level. There is a negative correlation between brightness temperature of cloud top and rainfall intensity near surface. The number of lightning frequency in Sichuan Basin is heigher than the TP areas, and lightnings mainly appear in the clouds with lower bightness temperature.