Numerical experiments with a five-level global atmospheric prediction model using a staggered, spherical, sigma coordinate system.

Abstract

Three cases of analytic data and one case of real data were numerically integrated using a 5-level baroclinic primitive equations model of the general circulation. Experiments were performed using initial winds derived from the linear balance equation and also winds derived analytically. The feasibility of using the linear balance equation to initialize the wind field was examined. In all cases, the forecasts remained meteorological and reasonably well-behaved. Nevertheless, the forecasts derived from initial winds generated by the linear balance equation excited large, operationally-undesirable inertial-gravity waves, while the forecasts from analytically determined initial winds remained virtually free of such small scale "noise".