Spectral Representation of Horizontal Wind in Numerical Models of the Atmosphere

Abstract

Use of the primitive equations in spectral models of the atmosphere raises certain questions about the representation of the horizontal components of velocity therein. A barotropic model is constructed and integrated using two types of velocity representation. In the first, (u,v) are expanded directly in spherical harmonics while the second represents (u cos?, v cos?) in like manner, where ? is latitude. These integrations are compared and it is concluded that the direct representation of (u,v) is an allowable procedure.