Formulation of efficient finite element prediction models

Abstract

This report compares three finite element formulations of the linearized shallow-water equations which are applied to the geostrophic adjustment process. The three corresponding finite difference schemes are also included in the study. The development follows Schoenstadt (1980) wherein the spatially discretized equations are Fourier transformed in x, and then solved with arbitrary initial conditions. The six schemes are also compared by integrating them numerically from an initial state at rest with a height perturbation at a single point. The finite difference and finite element primitive equation schemes with unstaggered grid points give very poor results for the small scale features. The staggered scheme B gives much better results with both finite differences and finite elements. The vorticity-divergence system with unstaggered points also is very good with finite differences and finite elements. It is especially important to take into account these results when formulating efficient finite element prediction models. (Author)