Diagnosis on Energy Budget and Moisture Supply of Matsa after Landfall
麦莎台风登陆后能量过程与水汽供应的诊断研究

A diagnostic study has been conducted on the sustaining mechanism of Typhoon Matsa(2005) which traveled northwards after landfall in Zhejiang Province with a Strong Tropical Storm intensity.The Ertel Potential Vorticity(EPV) analysis indicates that a small positive EPV anomaly at the bottom of the approaching midlatitude trough was an important source of vorticity for the modest re-intensification of Matsa,the main positive EPV area merged with Matsa after 9 August,2005.The kinetic budget anaysis shows that the kinetic energy(KE hereafter) generated by non-divergent wind component was prior to the intensification of Matsa,divergent wind component was the main kinetic energy source in the low-level,and the cumulus(sub-grid scale system) convection is another mechanism of upward kinetic energy transportation other than large scale ascending.The difference of KE transported by non-divergent wind between Matsa and Agnes(1972),which experienced strong re-intensification,may be an important reason why Matsa did not reintensify greatly as Agnes.Traveling on land,there are two moisture channels providing abundant water vapor for the maintenance of Matsa.