Analysis And Numerical Simulation Of Typhoon (0519) Landed In The South East Of FuJian

By using satellite photo,radar echo and the conventional observational datasets, we studied the synoptic situation and infecting system which cause heavy rain occurred during 1～4 Oct 2005 when Typhoon LongWang (0519) landed on Fujian . The results show that the subtropical high to the east of the shallow slot though in the northeast China and the Continental High to the weast of the shallow slot though in the northeast China are the mainly large-scale circulation systems. The radar echo and satellite photo data can track the route of typhoon and rainstorm primely.Based on the two-way nested non-hydrostatic mesoscale numerical model(MM5V3), the whole process during typhoon "LongWang" landed Fujian is simulated. The model can simulate "longwang" well. By using of the high space-time resolution data of the model ouput, the primary diagnostic analyses are studied and the results show that: (1) Influenced by the the earth's surface, the dissymmetry structure of typhoon produce some extremal areas of strong vapour flux ,convergence , positive corticity and strong ascent. It is these extremal areas that primely cause the extra heavy rain in FuZhou city. (2) Vertically partical helicity( K helicity) is relation can indicated the typhoon rainstorm well. During the heavy rain occured, there is postive K pole at low levels and the center of positive K is excellent agreement with the rainstorm. The hourly precipitation at single station is correlated positively with the vertically partical helicity at 700hPa perfectly. (3) There are high CAPE overhead in the rainstorm area. The distribution of positive potential vorticity at high level and negative potential vorticity at low level is closely corredted to the rainstorm.Also by using of the simulated data the structure of typhoon is analysed before and after the thphoon "longwang" landed. It is found that warm temperature center appears around the center of typhoon. The extremum of physical quantities except warm temperature center generally appears on the area 100-200km to the center of typhoon. After typhoon landing Fujian, the thermodynamic, dynamical structure and circulation has changed markedly in intensity and space although some character is reserved as same as typhooh circulation.Finally, the terrain sensitive experiments proved that: Terrain can increase the precipitation obviously. The higher the terrain , the stronger the convergence lifting force and the more the precipitation.