ON THE FORMATION OF THE THERMAL WIND EQUILIBRIUM STATE IN A SIMPLE BAROCLINIC ATMOSPHERE

In this paper, the principle of the variation of the vertical motion in the adjusting process of thermal wind is discussed by means of a simple two-layer baroclinic model. When the thermal wind vorticity of the wind field is larger than that in the temperature field, the ascending motion must be accelerated, and vice versa. For the baroclinic system in the upper troposphere between 250 mb and 750 mb, the temperature field adjusts itself towards the wind field when the scale of the system is smaller than a critical scale, L_0, and the reverse is true when the scale of the system is larger than L_0. This is demonstrated by calculated examples in which two horizontal scales are used. They are about 1000 km and 300 km respectively. In the former (1000 km), the adjustment is mainly towards the temperature field, and in the latter it is mainly towards the wind field.