台风期间台湾岛周边海域海面风场特征的卫星遥感研究

利用1999~2005年QuikSCAT卫星遥感资料,对台风期间三种台风路径下台湾岛周边海域海面风场变化特征及成因进行了分析.结果表明,尽管台风强度被不同程度低估,台风中心附近风向反演受降雨影响明显,但遥感海面风场的大致形态仍较为合理.地形对风场特征的形成有着显著作用,它导致了台湾海峡内大风(>10 m/s)天气提前出现、中央山脉两侧背风槽(或诱生低压)形成、中央山脉两端下风面“角流”形成等现象.海峡内大风天气是否提前出现与台风中心的位置有关.不同台风路径下,“角流”和背风槽的位置和范围不同.

Remote Sensing Study of Sea Surface Wind Field Around Taiwan Island During Typhoon Periods

The QuikSCAT remote sensing data from 1999 to 2005 were used to study the features and mechanisms of sea surface wind fields around Taiwan Island during typhoon periods.Twelve westward or northwestward typhoons were selected,and separated into three categories due to the situation of typhoon track and Taiwan Island.Three typhoons were analyzed in detail as typical cases of three categories.The result showed: The strength of typhoons were underestimated to different extent and the wind direction retrieval near the typhoon center was influenced seriously by rain,however the general pattern of remote sensing wind fields were reasonable.Terrain had prominent effects on the formation of wind field features;it caused some interesting phenomena,such as strong wind(>10 m/s) appearing earlier in Taiwan Strait,the formation of leeward trough and "corner flow" to the flanks of Center Mountain Range(CMR) and downstream of the tips of CMR respectively.Whether the strong winds appeared earlier still depended on the location of the typhoon center.Along different category of tracks,the location and scope of "corner flow" and leeward trough were different.