中文摘要：

利用卫星云图和NCEP再分析风场资料对0207号台风HALONG云系和风场变化特征进行了分析。结果表明，台风云系不对称的结构，台风西侧高空急流向台风中心的移动和辐散是台风迅速减弱的主要原因。为了了解不对称台风环流对台风强度的影响。还对比分析了0417号台风AERE、0216号台风SINLAKU在中国沿海减弱和重新加强的环流特征。在低层流入台风中心南侧的西风分量大，在高层流入台风中心西侧的北风分量小，有利于台风的加强。台风南、北两侧的东西向风场垂直切变梯度差异不利于台风加强。东西向风场垂直切变对台风强度的影响比南北向风场更重要。

英文摘要：

Using the cloud imagery and NCEP reanalysis data, the work studies the characteristic of the cloud band and wind flow for the weakening of the 7^th typhoon in 2002. The results show that the weakening of the typhoon is influenced by the asymmetric structure of the cloud band, high-level jet and divergence flowing into the typhoon. Besides, the research on weakening and re-intensification of the 4^th typhoon in 2004 and the 16th typhoon in 2002 show that the development of U-component at the low level in the south of typhoon environment flow is helpful for re-intensification of the typhoon, but the development of V-component at the high-level in the west of typhoon environment flow is destructive for typhoon structure.