摘要
本文采用含有摩擦力项的台风梯度风方程,其离心力项中曲率半径的计算考虑了台风移动的因素,由此得到的台风风场模式,其梯度风摩擦修正系数c和风向内偏角β都是变化的。c一般从台风外围的0.6以下向台风中心方向递增,到台风眼壁附近其值接近1.0;β由外围的35°左右向台风中心方向递减,到眼壁附近减为5°以下,这比以往所用模式都有明显的改进。
If frictional drag is considered in the equation of gradient wind for a stationary typhoon with circularly symmetric distribution of pressure, the balanced equations for the forces can be expressed asSolving the above set of equations, velocity of gradient wind ν(k,c) and inner deflection angle β(k.c) can be obtained.ν(k.c) and β(k.c) represent the effects of frictional drag and moving velocity of typhoon respectively. Now, setting K = 0, we can find ν(0.c), and β(0.c) (here, β(0.c) = 0) ,and then define a frictional correction coefficient c as v(k.c)/v(0.c) (i.e. c = ν(k.c)°/ν(0.c)).In the case of Myers pressure expression, the computational results show.1. Both c and β are variables.The characteristics in their radial distributions are that c is about 0.6 at the edge of typhoon, and increases inward to nearly 1 in the vicinity of typhoon centre: β is about 35° at the edge and 2°-8° near the centre, it decreases inward;ν(k.c) reaches its minimum at the edge and the maximum appears at r = R0, it sharply decreases inward further.2. C and β are also related to the characteristic parameters △P, R0,,Yc and Vc. For instance, β decreasen and c increases when △P becomes larger. It is consistent with the case that typhoon develops and enhances the rota-tios of its flow.To sum up, the model proposed here is more reasonable than those with c and β as constants,in the simulation of wind field of real typhoon by using statistical data.
出处
《热带海洋》
CSCD
1989年第1期58-66,共9页
基金
国家自然科学基金资助项目
