THE NUMERICAL SIMULATION AND ANALYSIS OF A HEAVY RAINFALL IN JULY 2003 BASED ON RADAR DATA ASSIMILATION

CINRAD/SA Doppler radar data and ARPS data analysis system(ADAS) were used to adjust the initial field.Then the adjusted initial field was used as initial field for the mesoscale model WRF(The Weather Research and Forecasting Model) to simulate a rainstorm process which occurred on 4—5 July 2003.Then the creditable simulated results were used for analysis of mesoscale convective systems.The analysis results show that Doppler radar data are helpful for the accuracy of simulated heavy rainfall and in turn the high resolution simulation is helpful for the analysis of the structure and evolvement of mesoscale systems.Large scale background is helpful for the-β convective system,but vapor and ascending movement have strong impact on the development of mesoscale systems.The-β convective system has one or more branches of ascending movement,which is related with the rainfall.Two-β convective systems developed during the process of rainfall and the centres of the systems were moving from low to high level during their development.