Mesoscale Numerical Simulation And Analysis Of Heavy Rainfall Caused By A Typhoon

By making use of globle reanalysis data of four times oneday from NECP/NCAR for background field and simulating a heavyrainfall after landing by using nonhydrostatic mesoscalemodel MMSV3,the diagnostic result to physical parameter ofreanalysis data and the output of simulation shows the earlystorm rainfall of warm convective precipitation andprevailing south wind is caused by air convergence on the topof inverted trough and late one majoring in east wind includesboth warm convective and frontal rainfall because of the northcold air's movement south and the new cyclone's join.On the weak phase of the typhoon, the vary of the top andlow level jet stream's direction and intensity affected bythe cold air and the new typhoon change vapour and energychannel and the position and intensity of heavyrainfall,owing to the division and the deviation of the uppermovement center. The rain center related to the vapour channeltightly lies in the max zone of the wind shear curvature andthe vapour convergence lift. In addition, it is located in theeastern of mountains because of the topographical action.Because of the tight concern of the vary of the weathersituation and the produce and progress of mesoscale wave,thefilter can probe the inner mechanism of the weatherdevelopment. The muit-scale wave, meso-βscale,meso-αscaleand so on,produced by the interaction of the meso-scalewave,the typhoon cyclone,the cold air,etc.is the major systemto this rain. The filtering of the meso-βscale system showsthe revolution of the weather system. By analyzing themesoscale filter's result in cooperation with the output ofthe high resolution model,on the late period of the rainfallthe meso-αscale caused by the interaction of the weakmesoscaie waves is the leading effect and the new valid methodof the meso-scale analysis.As a small scale spatial wave, the meso-αone take advantage of the heavy rainfall,which vertical scale,when thehorizontal scale is about from 100km to 300km, also isshort,which show the reverse phase in the 500hpa level,whilethe strong convergence in the low level.