Identification and elimination of an inflow boundary computational solution in limited area model integrations

Abstract

The linearized non‐divergent barotropic vorticity equation in one dimension is used for the study of a problem associated with the specification of lateral boundaries in limited area models. This problem presents itself in the form of a “pillow” that builds up near the inflow boundary of the model. Linear analysis shows that this pillow can easily be eliminated. Linear integrations carried out with a corrector seem to be reasonably accurate.

Similar integrations with the linearized shallow water equations in one dimension also produce a pillow and the same corrector gives improved results. Additional runs are performed in order to show that some commonly used nesting strategies do not control this computational problem in a satisfactory manner. It seems that these strategies could be improved with an appropriate corrector.