The Diagnose Analysis And Numerical Simulation Of A Local Torrential Rain In Tian Jin

A local convective torrential rain which happened in Tianjin urban on 28-29 June 2005 is analyzed by using reanalysis data of NCEP, radar data and the data of the automatic stations. And the mesoscale numerical model MM5(V3)is used to simulate the process. Using the model output with high spatial and temporal resolution, the characteristic and mechanism of the process can be studied in more detail. The result of the research shows that meso-scale activities in this process played an important role in this precipitation including the large-scale circulation system and the vapor it provided. The analysis of the radar data and the data of the automatic stations shows that the strong radar echo intensity, the convergence and the longest last time appear in the urban. Radar stations and automatic data integration can reflect the changes in the development of small and meso-scale system, and the radar profile will more directly reflect the precipitation. When the wind of urban areas is from east, moisture from the sea will make greater precipitation. The modify of the underlying earth's surface is very important to the local torrential rain. The movement of the surface convergence lines, the gravity wave and the delivery of water vapor also can be well reflected by the model results.