Diffusion and Numerical Filters

Abstract

Applications of low-pass filters or implicit diffusion are found to be extremely beneficial in a simple model problem that contains an oven-ordered advection scheme based on a symmetric stencil. In contrast, the effects are negative when either is applied to an odd-ordered approximation of advection that uses an asymmetric stencil. Also, the discriminating power of filters is shown to be helpful in identifying how small spatial-scale information influence a numerical weather prediction forecast.