高原热力作用下的非绝热Rossby波(英文)

Thermal Effects of the Tibetan Plateau on Rossby Waves from the Diabatic Quasi-Geostrophic Equations of Motion

从含非绝热项的准地转运动方程组出发,分析了青藏高原大尺度热力作用下非绝热Roaaby波的一些性质。从理论上证明当背景西风气流为正压时,冬季高原冷却作用有利于Rossby波的经向传播。又由非绝热Rossby波的频率方程说明冬季高原的热力作用是中高纬季节内振荡的重要激发机制。此外,当背景西风气流为斜压时,求解了高原热力作用下非绝热Rossby波的频率,并由频率方程说明冬季高原冷却作用有利于波动向不稳定方向发展,而夏季高原的大尺度热力作用对波动稳定性的影响存在临界值。

From the diabatic quasi-geostrophic equations of motion, the authors analyze the characteristics of diabatic Rossby waves including the thermal effects of the Tibetan Plateau. When the basic zonal flow is barotropic, it is demonstrated that the cooling of the Tibetan Plateau in winter not only facilitates the meridional propagation of Rossby waves but is an important driving mechanism of the intraseasonal oscillations in middle and high latitudes. When the basic zonal flow is baroclinic, it is found that the cooling of the Tibetan Plateau in winter facilitates the instability of Rossby waves, while in summer there is a threshold for the influence of the heating of the Tibetan Plateau on the stability of Rossby waves.