Diagnosis Of The Movement And Structure Of Typhoon Morakot (2009) Using The Potential Vorticity Tendency Approach

Based on the non-steering effect theory, used the Potential Vorticity Tendency (PVT) approach can quantitatively calculated the direct contribution of diabatic heating and other physical processes to TC motion (non-steering effect). Through the numerical simulation of typhoon Morakot (2009), we improved the original PVT diagnostic methods by including the development of TC asymmetric circulation, and then used the improved approach to analyze the impact of different physical processes on Morakot’s movement. The results reveal that the track of Morakot during landfall is majorly determined by the steering flow, and the effects of diabatic heating and other physical processes mainly lie in maintaining vertical structure. However, the influence of non-steering effect could not be ignored at some times, especially during the short-term oscillations of TC translation speed. Then we used the improved PVT approach to analyze the structure of Morakot, we know that the adjustment between the diabatic heating and the relative advective make for the structure complete.