热带气旋海面最大风速半径的计算

利用含有摩擦的平面极坐标水平运动方程组, 引入藤田气压模式, 在热带气旋域内最大风速为已知的条件下, 经过合理的简化和推导, 得到了呈稳定状态的海面移动非对称热带气旋的最大风速半径的计算方案。分析结果表明, 当最大风速越小、中心气压越低、环境温度和气压越高、纬度越低或摩擦系数越小时, 热带气旋的最大风速半径就越大;反之, 最大风速半径就越小。最大风速和它半径上的最小风向内偏角出现在热带气旋移向的右后侧。对9109号和9115号热带气旋的计算表明, 最大风速半径在发展初期增加, 在发展后期减小, 而在衰减期迅速增加。

Calculation of Maximum Wind Velocity Radius of Tropical Cyclone on Sea Surface

By the agency of Fujita pressure formula, a method to calculate the maximum wind velocity radius of mobile asymmetric tropical cyclone (TC) over the sea in the circumstance that the strength keeps constant is developed in terms of the horizontal momentum equations with frictions in the polar coordinates after the reasonable simplification and derivation in the presence of the maximum wind speed. The result suggests that the maximum wind velocity radius will be large under the conditions that the maximum wind is small, the central pressure is low, the environmental air temperature and pressure are high, and the TC locates at a the low latitude or the friction coefficient is small, and vice versa . The maximum wind speed with minimum inner deflection angle resides at the right back side of the TC moving direction. The case studies of 9109 and 9115 TC indicate that the maximum wind radius increases in the initial stage of the TC development, decreases in the mature period, and enhances rapidly in the decay phase.