| An analysis of the meso-scale circulation in the No. 0312 typhoonKROVANH process is made in this work. It is revealed that convectionalcloud cluster from South China Sea and Gulf Bengal keep infloodingcontinuously into the typhoon circulation, the convergence of the vapor at lowlever and the divergence of the vapor at high lever, and the strong risingmovement are the main reasons of the occurance of typhoon heavy rainfall.By using observations from meteorological satellite, the meso-scale spiralbands is studied and then the meso-scale characteristics of typhoon heavyrainfall is discovered. Analyzing the physics structure of vorticity, divergence,vertical velocity etc. indicated the physics fields are favorable for theoccurance where the physics values are well according to the heavy rainstormpositions.The meso-scale numerical model MM5(V3) is used to simulate theKROVANH typhoon heavy rain process on 24～26 August 2003. Using themodel output with high spatial and temporal resolution we study thecharacteristic and mechanism of the rainfall in more detail.It turns out that the convergence center of Q vector divergence at850hpa is favorable for the occurance of heavy rainstorm. There are towaccording divergence center in the Q vector divergence at 850hpa in NE-SWdirection on on Southeastern coast of China. The stronger convergence, themore corresponding for the beginning of the heavy rainfall. Since theageostrophic rising movment excitateds and maintains in the convergence areaand the ageostrophic subsidizing movment excitateds and maintains in thedivergence area, typhoon heavy rainfall occurs near the same updraft area ofthe two circulation. The change of Q vector can reflect the movement anddevelopment of synoptic system and the position and intensity of therainstorm. Q vector divergence field on vertical section plane along NE-SWdirection on Southeastern coast of China submit piece form district ofconvergence and divergence, have reflected meso-scale character.
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