Analysis of a Brief Torrential Rain Event in Autumn in Xinjiang

Based on the data of hourly precipitation in Xinjiang and the data of FY- 2D Stationary Meteorological Satellite from China Meteorological Agency and the reanalysis dataset from the NCEP / NCAR reanalysis project,the mesoscale characteristic and the mechanism of a brief torrential rain event in Xinjiang are analyzed by the 25-point smooth filter methods. The results show that the temperature in Bozhou in the earlier stage is slightly higher than normal,w hich provide the thermodynamic conditions for the brief torrential rain event in late fall. There is a mesoscale vertical circulation cycle in Bozhou,w hich provides the favorable dynamic condition for the torrential rain. The position and the moving direction of mesoscale cyclone and TBB are all the same. Unsteady stratified atmosphere has great impact on the maintaining and development of the mesoscale convective cloud mass over Bozhou. Continuous moisture convergence and potential instable energy transportation in the low er layers provide enough w ater and energy for the lasting heavy precipitation over the rainstorm area. The effect of terrain to the heavy rain event is very important. The surface mesoscale convergence line and mesoscale depression may be the trigger system.