热带气旋异常运动的曲率变化特征

CURVATURE VARIATION FEATURES OF TROPICAL CYCLONE ANOMALOUS MOTION

关键词:  台风  移速  轨迹  异常运动  曲率

Key words:  typhoon  moving speed  track  anomalous motion  curvature

摘要:

运用热带气旋曲率理论模型,选择不同环境及移速特征的台风个例,通过动力学诊断分析,揭示了台风异常运动的关键影响因子的物理机制及其规律。研究结果表明,热带气旋曲率理论模型中影响台风移动的相关特征能够在一定程度上描述出天气系统等环境因子对台风异常运动的综合影响规律。诊断分析结果表明,台风移速、涡旋动力结构、外围副热带高压带及西风槽的非定常变化均可影响台风移动轨迹曲率,尤其是对异常路径和转向点的影响,其突变规律符合台风移动规律。台风移动与系统动力结构有关,台风最大风速与中心气压突然增强或减弱时都会导致台风的突然转向。

Abstract:

Based on a theoretical model of tropical cyclone and through dynamical diagnostic analyses, typhoons with different motion speed and ambient fields are used to investigate the physical mechanism and law of typhoon anomalous motion. It is found that the related characteristics of the mathematical model about tropical cyclone motion curvature are of the ability to some extent to describe the composite impact of synoptic systems such as ambient factors on the anomalous tracks of tropical cyclones. Results show that the moving speed, vortex dynamical structure, nonlinear variance of subtropical high and westerly trough exert great influence on the motion curvature of typhoon, particularly on its anomalous tracks and sudden change, which, as well, are in agreement with the law of typhoon movement. Typhoon would change its direction abruptly not only as its maximum wind speed increases and its lowest pressure drops conspicuously but also as its maximum wind speed decreases and its lowest pressure rises exceptionally.