热带气旋移动的数值模拟和临界点现象

A NUMERICAL STUDY ON TROPICAL CYCLONE MOTION AND THE CRITICAL POINT PHENOMENON

用一个带有热力强迫和耗散项的准地转正压模式,实施了16组积分时间大于7d的数值试验,研究了在环境流场和环境加热场共同作用下,热带气旋的移动路径问题。结果表明,随着环境流场参数、环境加热场参数和热带气旋尺度参数取值的不同,在模式大气中,清楚地复制出逆时针打转、蛇行摆动、向西移行和突然北折等截然不同的运动形态,并显示出具有非线性特色的临界点现象。

By using the barotropical vorticity equation with thermal forcing and dissipation terms, sixteen numerical experiments whose integration times are longer than seven model days are performed in order to investigate tropical cyclone motion under the influence of enviromental flow and local thermal forcing. Results show that in various range of the parameters describing the intensity of environmental flow, the thermal forcing and tropical cyclone size, various tracks can be reproduced, which include counterclockwise revolution, looping motion, northwestward shift and abrupt turning northward, exhibiting features of nonlinear systems.