EVALUATING THE PERFORMANCE OF WESTERN NORTH PACIFIC TROPICAL CYCLONE INTENSITY GUIDANCE. PART Ⅱ:INTENSITY FORECAST ACCURACY IN DIFFERENT LIFE STAGES

摘要

The accuracy of eight tropical cyclone（TC） intensity guidance techniques currently used in the East China Regional Meteorological Center during the 2008 and 2009 western North Pacific seasons has been evaluated within two intensity phases:intensification and decay.In the intensification stage,the majority of the techniques indicated ＞ 60% probabilities of the errors of forecast 12-h intensity change within ±5 ms-1 from the 12- to 60-h forecast intervals,while none had capability to predict the rapid intensification and most of them had a bias toward smaller 48-h intensity changes at the beginning of the stage.The majority of the guidance techniques showed ＞ 70% probabilities of the errors of forecast 12-h intensity change within ±5 ms-1 through 60 h during the decay phase,and the techniques had little capability of predicting rapid decay events.It is found that the evaluated statistical models had difficulty in predicting the strongest cases of decay 36 h after peak intensity,whereas the dynamical and official forecasts were seemingly able to produce some large decay rates.