Study On Improvement Of Ageostrophic Wet Q Vector In Inhomogeneous Saturated Atmosphere And Its Application To Precipitation Associated With"Morakot" Typhoon (2009)

Combining a torrential rain process, which was caused by typhoon Morakot (No.8in2009) during the landing Fujian province, the improvement of ageostrophic wet Q vector in inhomogeneous saturated atmosphere(Qum) is carryed out considering convective latent heating. The results are as follows:(1) Typhoon Morakot landing Fujian province from08:00BST9August to08:00BST10August in2009, gives rise to wide range heavy rainfall in most parts of Zhejiang province and middle and north of Fujian province. The rainfall process is simulated successfully by the Weather Research and Forecasting (WRF) model.(2) We complete the improvement of Qum vector by considering convective latent heating release. The analysis shows that the ability of simultaneously reflecting and diagnosising precipitation of the convergence field of the modified Qum vector divergence enhanced significantly.(3) The "Morakot" typhoon rainstorm in the strong precipitation occurring in the process of meeting the three necessary conditions for development:changing conditions, lasting increase in the flow and instability in the structure of atmosphere.(4) This time there is an obvious strong precipitation process of hollowing out phenomenon.Combining a torrential rain process, which was caused by typhoon Morakot (No.8in2009) during the landing Fujian province, analysis of causes of heavy rain is as follows:(1)Improved600hPa Qum vector convergence after some correspondence between the precipitation field over the same period, with precipitation, and the evolution of development also has strong ability to reflect. At the same time to a certain extent reduce the "empty" and "false negatives", Qum vector diagnostic capability as well as to further improve.(2) Create "Morakot" Typhoon heavy rain in this process is an important reason for this is the amount of moisture conditions. Low level moisture convergence for Typhoon "Morakot" provides plenty of moisture and water vapor fluxes with high degree of weakening, a striking "wet on" knot. We can conclude that "dry on wet under" distribution of atmospheric humidity stratification, generally low-level air warm and wet, dry and cold upper air, causing the atmosphere in a very unstable state, and energy release in the atmosphere, full development of Typhoon heavy rain.(3)"Morakot" Typhoon another important reason for the strong precipitation process is not the maintenance of stable stratification. Equivalent potential temperature decreases with height decrease faster, stronger convective instability of a gas, triggering heavy rain caused more likely. In addition, based on the data including radius of maximum winds form JTWC (the Joint Typhoon Warning Center), the tropical cyclones’radius of the last closed isobar, tropical cyclones (TCs)’best tracks form Shanghai Typhoon Insititute and the Black Body Temperature (TBB) of the Japanese geostationary meteorological satellite MITR IR1and combining13tropical cyclones which landed in China again after visiting Taiwan during the period from2001to2010, we analyze the relationship between the number of convective core within TC circulation and intensity of TC with the method of convective-stratiform technique (CST) and statistical synthesis.