【摘要】 将一类暖性青藏高原低涡考虑为受加热和摩擦强迫作用并满足热成风平衡的轴对称涡旋系统,给定符合高原地面加热特点的加热分布函数,通过求解简化后的柱坐标系中的涡旋模式,得到了低涡对应的流函数、水平流场、水平散度场和垂直运动场的解析解,分析了地面热源对高原低涡流场结构的作用,给出了高原低涡眼壁内、外侧以及不同高度上的水平流场、水平散度场和垂直流场的结构特征,对影响低涡生成的主要因子进行了讨论。研究结果揭示了地面热源强迫对高原低涡的形成及结构特征的重要作用。更多还原

【Abstract】 The plateau vortex in this study is a type of vortex generated over the main part of the Tibetan Plateau. It is mainly on 500 hPa isobaric surface with its horizontal scale from 400 to 500 km and life circle from one to three days. The temperature structure of most plateau vortexes is warm. The Tibetan Plateau vortex is advantageous to severe weather processes. They usually induce storm rainfall or thunderstorm on large scale in the upper reaches of the Yangtze River (especially in Sichuan Basin) and even in the downstream of the plateau, when they develop and move eastward out of the plateau. In this paper, the vortices over the Tibetan Plateau are assumed to be axisymmetrical and thermal-wind balanced systems forced by specific surface heating and friction, and solved as an initial-value problem of linearized vortex equation set in cylindrical coordinates. The role of surface heating on the structure of plateau vortices is analyzed in detail and horizontal and vertical flow field and divergence of the vortex are drawn. The results show that surface heating play an important role in the genesis of plateau vortex and its structure.更多还原