COLA Report 70

A Model for Transient Eddy Momentum Fluxes in the Upper Troposphere

Timothy DelSole

September 1999

Abstract

A parameterization for transient eddy momentum fluxes is constructed based on the hypothesis that planetary waves radiating from low-level baroclinic eddies act effectively as a random forcing of the upper troposphere. The response of the upper troposphere is modeled by a linear, barotropic, nondivergent vorticity model with Rayleigh friction and scale-selective damping. The added dissipation crudely represents the effect of orographically induced gravity wave drag, verticle diffusion, and other processes needed to balance momentum fluxes reasonably well and can be understood physically from balance constraints and Rossby wave theory.

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last update: 28 October 1999
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