The Response of a Model Atmosphere in Middle Latitude to Forcing by Topography and Stationary Heat Sources

Abstract

The Midlatitude standing waves forced by topography and stationary heat sources are investigated by means of a quasi-geostrophic, linear, steady-state, 34-level model with eddy viscosity and Newtonian cooling effect included. The results show that increased vertical resolution contributes significantly to the solution of the finite difference equations of motion and the thermodynamic equation, i.e., our 34-level model with increased vertical resolution in both the troposphere and stratosphere, gives better results when compared to simpler models such as the "two-levels" model.
The computed vertical and zonal distributions of amplitude and phase for winter are in good agreement with observed standing geopotential and temperature waves. Similarly, computed and observed summer standing wave positions are also fiarly consistent. However, the computed trough over the central Pacific Ocean in summer appears to be too weak.
The eddy viscosity, and the meridional wavelength of the topography and diabatic heating seem to have a strong influence on the response of a model atmosphere to forcing by topography and diabatic heating.