A Galerkin finite element-spectral weather forecast model in hybrid coordinates

✍ Scribed by J. Steppeler

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 486 KB
• Volume: 16
• Category: Article
• ISSN: 0898-1221
• DOI: 10.1016/0898-1221(88)90021-1

✦ Synopsis

Al~tract--An atmospheric model is presented using the spectral method for horizontal discretization and a finite element method for the vertical. The vertical coordinate is discretized in a hybrid system, being a P-system at the top of the atmosphere and a ~-system near the surface. For intermediate levels there is a smooth transition between the two systems. An energy-conserving scheme is obtained by using a Petrov-Galerkin method with density as a weight, An efficient method of computing the Galerkin integrals is achieved by introducing a collocation grid. The horizontal discretization uses the spectral method with spherical harmonic basis functions and triangular truncation with meridional wavenumber up to 106. A set of test forecasts was done using 19 vertical levels. The forecasts were compared to those of a model using a finite difference technique for the vertical. The finite element model showed an advantage with respect to an averaged correlation measure.