The Response of a Hemispheric Multi-Level Model Atmosphere to Forcing by Topography and Stationary Heat Sources (I) Forcing by Topography

[摘要] The standing waves responding to forcing by the Hemispheric topography are investigated by means of a quasi-geostrophic, steady state, 34-level model, with Rayleigh friction, the effect of Newtonian cooling and the horizontal kinematic thermal diffusivity included in a spherical coordinate system.The results computed by this model show that the topography at high latitude, such as Greenland Plateau, plays an important role in the standing planetary waves responding to forcing by the Hemispheric topography, and the anomaly of standing waves is connected with a zonal mean wind at the surface at 70°-85°N in winter. The computed results show also that the standing waves responding to forcing by the Hemispheric topography can be propagated vertically and laterally toward the region of larger refractive index, i.e., toward the region of weaker westerly winds at low latitudes.The amplitudes are maxima at 38km height, 60°N for wave number 1, and at 27km height, 60°N for wave number 2. In addition, they have secondary peaks in the upper troposphere at 20°-30°N. This may be considered as one of reasons for the formation of standing waves in the upper troposphere at low latitudes.

[学科分类] 大气科学