Comparative Study Based on TRMM Data of the Heavy Rainfall Caused by the Tibetan Plateau Vortex and the Southwest Vortex

A comparative study has been made on the three dimensional structures, distribution of the rain heights, and precipitation profiles of two precipitation systems generated by the southwest vortex (SWV) which occurred in Sichuan and Chongqing on July 17, 2007 and the Tibetan Plateau vortex (TPV) which occurred in the western part of Sichuan on July 21, 2008, respectively.The study is based on Tropical Rainfall Measuring Mission (TRMM) data, combined with the National Centers for Environmental Prediction (NCEP) reanalysis data.Results indicate that:(1) Both precipitation processes occurred in a southwest-northeast direction in the moisture convergence zone, and clouds were located in the southeast of the SWV.(2) Horizontally, the two precipitations processes consisted of a main precipitation rain band and several scattered precipitation clouds, and the rainfall intensity and scope of the TPV were much larger than those of the SWV.The common feature of these two mesoscale precipitation systems, detected by precipitation radar (PR), is that most of the precipitation was, which is characterized by a large scope and weak precipitation intensity.However, the contribution of convective rains to the total rainfall was much larger, and the ratio and contribution of convective precipitation to the total rainfall in the SWV was larger than it was in the TPV.(3) Vertically, the rain height in the two heavy precipitation systems increased with an increase in the surface precipitation rate, and the maximum rain height was close to 16 km.However, the rain height in the SWV was higher than that of the TPV, indicating weaker convective activity in the TPV.(4) The progress of collision and growth of raindrops and the latent heat release mainly occurred below a height of 8 km.But the change in the SWV precipitation was greater than that of TPV, and the SWV showed a greater total precipitation contribution than the TPV at a height layer of 8-12 km.