“北冕”后期路径左折和强度突然加强成因分析

Analysis on the Left Turn of the Later Period Route and the Intensity Sudden Strengthening of "Beimian"

利用T213、ECMWF数值预报资料和热带气旋历史资料,对0809号强热带风暴"北冕"路径和强度变化特征进行分析,表明:"北冕"登陆后路径发生左折进入北部湾的主要原因是,(1)副热带高压影响,(2)"北冕"结构不对称,(3)辐合带吸引作用及"双台风"效应,(4)"北冕"环流东北风分量大于西南风分量,(5)沿海地形作用;"北冕"进入北部湾后强度增强的主要原因是,(1)热带辐合带在华南沿海活动,(2)西南季风爆发处于活跃期。

By using numerical forecast data and historical data of tropical cyclones,the cause of left turn of the route and intensity sudden strengthening of ＂Beimian＂ were analyzed.The result shows that the main causes of ＂Beimian＂ left turn to Beibu Gulf are：（1） the impact of subtropical high,（2） the unsymmetrical structure of ＂Beimian＂,（3） the convergence zone attraction and ＂The double typhoon＂ effect,（4） component weight of northeaster wind of ＂Beimian＂ circulation is greater than that of southwest,（5）the role of the costal terrain.And the primary reasons of ＂Beimian＂ intensity sudden strengthening after entering Beibu Gulf include the active intertropical convergence zone in the South China coast and the active southwest monsoon.