台风云系的非对称结构和特定的OLR场与台风的异常移动研究

AN INVESTIGATTON OF THE RELATION OF ASYMMETRIC STRUCTURE OF TYPHOON CLOUD SYSTEM AND SPECIFIC OLR FIELD TO UNUSUAL TYPHOON MOVEMENT

摘要:

运用气象卫星资料,研究了西北太平洋上14个台风和强热带风暴的北翘、西折、转向和打转等异常移动,发现:台风中心附近某一方位的中尺度对流活动,造成台风云系的非对称分布和特定的OLR场,导致台风的异常移动;对流活动出现的不同方位和OLR低值区轴向对台风未来的移动有着很好的指示。对路径最复杂的四个台风作了详细分析。

Abstract:

The unusual typhoon tracks, such as turning northward and westward and recurving and looping, that occurred in foureen typhoons and severe tropical storms over the North western Pacific Ocean in 1990, are studied using CMS enhanced IR imageries and OLR from NOAA-11. The results show that: (1) the asymmetric distribution of typhoon cloud system caused by mesoscale convective activities around the typhoon center leads typhoon movement. When the mesoscale convective activities apper in its southern to northeastern or northern sector, typhoon would move northward. When they appear in its western or southwestern sector, typhoon would turn westward, when they appear in its eastern or northeastern sector and the cloud system of a cold front or Subtropical jet stream joins the northern part of the typhoon cloud system, the typhoon would recurve northeastward. (2) The direction of the axis in lower OLR area around the typhoon center and its variation is closely related to the movement of the typhoon and the coefficient of correlation is up to 0. 83.All these above may contribute to better understanding unusual typhoon movement and improving its nowcasting and warning.