THE CHARACTERISTICS OF SUB-SYNOPTIC SCALE CIRCULATION OF TROPICAL CYCLONES SUSTAINING OVER LAND

Both of typhoon Winnie(1997) and Tim(1994) sustained over land for a long period(2-3 days) and caused severe rainfall after they made landfall. The former developed distinctly with its extratropical transition (ET)process while the latter dissipated gradually after it entered into the mid-latitude region. Scale discretion of TBB 1-degree grid data and NCEP reanalysis 2.5-degree grid data analysis was performed with filtering scheme. Then the sub-synoptic scale features of Winnie and Tim were compared based on movable coordinate.Besides, the conversion of kinetic energy and vorticity betw een tropical cyclone(TC) and sub-synoptic scale systems(SSS) were calculated on TC area mean basis.Results showed that the intensity change of TC over land was closely related to the SSS in TC circulation.