Helicity,Q Vector,MM5 And Their Effects On The Most Heavy Shower Caused By Typhoon Trough

It introduces mainly the process of the most heavy shower occurring in south seacoast of Zhejiang caused by typhoon trough from August 3 to 4 , 2001. By using NCEP lxl reanalysis data and satellite data ,we discuss the low cyclonic eddy and the most heavy shower caused by typhoon trough. Helicity, Q vector and their effects on the all process are seen. The MM5V2 model is used to simulate the most heavy shower and the low cyclonic eddy. The results show that there exits close relationship between helicity and the most heavy shower, the higher helicity might be one of the mechanisms for rain storm development. Staying high_level helicity and low_level helicity together can star heavy shower.In this process high_level helicity is as important as low_level helicity. Helicity and MM5 model used together can offer more correct low cyclonic eddy forcast and rain strom forcast. At the same time, the paper says that close relationship between Q vector divergence and the most heavy shower exits. The common region of high Q vector divergence and high helicity can forcast low cyclonic eddy and rain strom better. Using Q vector divergence, helicity and MM5 together can offer a fresh method to forcast rain storm. On the other hand, a substantial review on the developments on the theoretic of helicity, Q vector and the results of their main application are conducted completedly and systematically, along with a prospective study in this field.