尤特台风登陆过程中眼区结构变化的分析研究

尤特台风在登陆珠江三角洲期间,借助珠江三角比较稠密的观测网对它在登陆过程中眼区及其附近结构的变化进行分析研究.综合使用时间分辨率为6 min的多普勒雷达CAPPI(Constant Altitude Plan Position Indicator)回波图、每小时CAPPI径向风、高时空分辨的静止气象卫星云图、SSM/I(Special Sensor Microwave/Imager)和常规观测等资料.雷达图上发现眼区及邻近地区多处存在着比较强的最长可达150 km左右的直线状回波,直线回波带上嵌有多个强的回波单体.经过分析研究,认为雷达图上的直线状回波现象,与台风内区涡旋结构的变异有关.考察静止卫星红外云图上螺旋云带的强烈弯曲和云带前端低TBB值的现象,以及分析探空资料计算出来的相对涡度分布,认为直线回波现象与台风内区非对称的涡旋结构演变有关,那些直线回波带的形成可能是与眼壁附近存在的涡度相对高值区的推进相联系的.最后作者就台风登陆过程中内区涡旋结构变异的问题作一些讨论,认为台风在登陆过程中相对比较容易发生结构变异,从而有可能导致在登陆过程中移速加快和出现强天气等现象.

Research on Eye Structure Variation of Typhoon Utor During Its Landing

During Typhoon Utor landing the Pearl River area, we analysed the structure variation of typhoon eye and neighborhood by using relatively high density observation net in this area Doppler radar CAPPI images, the time interval between each image is 6 min, CAPPI wind field, high resolution GMS5 infrared data, SSM/I and conventional data are used The phenomena of straight line intensity radar echoes in several places near the eyewalls in which embed a few strong echo cells was found The research work showed that the phenomena of straight line echoes had something to do with the structure aberrance in inner region Analysed the phenomena of sharp bend in spiral bands and the lowest TBB value in forepart of spiral bands, as well as the relative vorticity distribution from sounding data, suggested the phenomena of straight line echos had something to do with the structure variation of asymmetric vortex, the formation of those straight line echoes might be due to the progress of relatively high value vorticity area existed near the eyewall At last, something about typhoon landfall and structure aberrance in inner region are discussed During landing typhoon relatively easily occurred the phenomenon of structure aberrance, i e , the movement of typhoon might speedup and occurred strong weather during landing