Static initialization of primitive equation models on a bounded, extratropical region

Abstract

Two filtered models (FM) are studied for their properties in providing initial data for primitive equation models (PEM) solved on a bounded, extratropical region. The methods are tested on actual data, and topography and friction are included. The results suggest that filtered models are powerful tools for suppressing gravity-inertia waves in the primitive equation models in cases where the horizontal normal modes are difficult to find. Inconsistencies between the initialization method and the prognostic model regarding vertical, finite differences and horizontal approximations at the lateral boundaries, may give rise to low-frequency “noise”. Inconsistent horizontal, finite differences chiefly give rise to high-frequency “noise” that can be removed by a time filtering technique.