Short-term forecasting with a multi-level spectral primitive equation model part I - model formulation

Abstract

A global baroclinic primitive equation model using the spectral technique has been constructedfor short- and me-dium-range numerical weather pre-diction. The spectral technique, which is aspecial case of the Galerkin method, employs spherical harmonic basis functions in the evaluation of all horizontal derivatives. The use of a transform technique allows all the horizontal operations to be performed efficiently and allows physical proces-ses to be evaluated in real space. The model employs a semi-implicit algo-rithm for time integration and finite differencing in the vertical. Physical processes include orography, moist convection, large scale precipitation and boundary layer processes. © Ta..