Vertical Transfer of Energy due to Stationary Disturbances Induced by Topography and Diabatic Heat Sources and Sinks

Abstract

The energetics of stationary disturbances is theoretically studied by means of the linearized form of the primitive equations of motion. Topographic and diabatic effects are prescribed as forcing. As the basic zonal current depending upon pressure, we have employed the winter normal conditions at 35°N latitude and at 60°N latitude. Our main interest will be to determine how the stationary disturbances are altered under different zonal currents and when changes in the lateral kinematic eddy-viscosity coefficient and surface friction coefficient are made.
The characteristics of the topographically excited disturbances of wave numbers about 3 is such that they can vertically transport sizable amounts of energy upward in the form of geopotential, after receiving kinetic energy through mountain effect and importing available potential energy from the zonal mean field. The upward transfer of geopotential is less pronounced at 60°N latitude than at 35°N latitude where the subtropical jet stream is located near 250mb. As for the thermally induced disturbances, a large amount of upward energy transfer occurs only at 60°N latitude where the vertical profile of zonal wind is characterized by the existence of the polar night jet stream, while no possibility of this type of upward transfer exists at 35°N latitude.