台风中心的旋转定位

台风在大气中绕着自己的中心急速旋转、同时又向前移动的空气涡旋。由于台风中心集中了台风绝大部分的能量和含水量,也是台风破坏力集中的地方,因为台风中心的定位对于台风路径预测和灾害预报来说都是非常重要的。传统的台风中心定位方式精度底,误差大,难以满足实际需要。为了准确地进行台风中心的定位,根据台风卫星云图的数字化特征和台风运动规律,提出了旋转定位方式。它的理论基础是,根据运动学和台风学原理,台风虽然是非刚性物体,但是其中心部分可相对看成是刚体的运动,因为热带气旋中心具有转动矢零的特点。这样,在卫星云图序列动画中,找出前后两次相应特征点的轨迹,即可算出其中的转动原点,也就是转动矢量为零的点。由于该方法结合了云图特性和运动因素,因而提高了精度和合理性。由此可见,对于台风这样的运动物体,结合其运动特征的中心定位法是台风中心定位的必然方向。

Typhoon Center Locating Using Rotation Feature Matching Method

Typhoon is a kind of atmosphere swirl which spins round its center and at the same time moves along rapidly. The center collects most of the energy and the water and is the place most destroy happens. Thus its location is very important for typhoon path prediction and disaster forecasting. Typhoon center location task is the continuous research of "eighth five year project" presided by China Meteorological Administration. The tradition prediction method is poor of precision and its error is too great to meet practical requirement. According to the satellite cloud digital image feature and typhoon movement rule, researchers co operate with experts in shanghai central broadcast bureau and advance a new method. In this paper, the rotation matching method is mainly discussed. The method is based on the fact that although the typhoon mass is a non rigid object, the center area can be treated as rigid object and thus the center is one point with zero rotating vector. Thus in typhoon's sequence images, one can find the matching feature points and calculate the rotation center point which has the character of zero rotation vector. This method improves the precision and objectivity. To moving objects like typhoon cyclone, location method combining its moving feature is the certain reasonable way.