South China Region Mutation Diagnosis Of Tropical Cyclone Intensity Analysis And Intensity Of Statistical Interpretation Forecasting Methods Developed,

The first section of this paper, NCEP reanalysis data are used in this paper to diagnose the large-scale environmental flow of tropical cyclones (TC) which their intensity changes rapidly before landfall in South China. Results show (1) TCs that intensify rapidly are located at the south or southwest of subtropical high and the southwest current are entangled in the center of TC in lower troposphere (850hPa). While most of TCs that decrease rapidly are at the northwest of subtropical high; (2) there is a favorable environment flow for these rapid intense TCs, which is strong convergence low level and remarkable divergence upper level; (3) the rapid intensification of TC is related to the sufficient water vapor transportation.The second section, A stepwise regression scheme with tropical cyclone intensity change as the dependent variable has been developed in South China, the predictors are involved in climatology persistence, synoptic predictors, satellite infrared data, regression is performed on 24-,48-,and 72-h forecasts. Regression results show that synoptic predictors that reflect dynamical forcing are mostly chosen, with forecast intervals extending, the variance contribution of climatology persistence predictors are less than that of synoptic predictors. The independent sample test results by a jackknife procedure show a large improvement over climatology and persistence(CLIPER) forecast scheme. There is a new attempt to add satellite infrared data in regression equation, results are not enhanced obviously in 24-, 72-h forecasts, while the result of 48-h forecast become promising correspondingly.