Forecasting With a Global, Three-Layer, Primitive-Equation Model

Abstract

A global, three-layer, primitive-equation forecast model in spherical and σ coordinates on a 3.75° latitude-longitude grid has been developed. It has a boundary layer and two layers in the troposphere, with the top of the troposphere and top of the model atmosphere coinciding at 100 mb. This is a modified and simplified version of the National Meteorological Center six-layer, operational forecast model. Mountains, radiation, sea-surface heating, convective adjustment, and ground-surface friction are incorporated. Initial data are generated from global analyses of winds and heights on seven pressure surfaces using Hough functions. The forecast model is described in detail, and examples of the forecasts and analyses extracted from the global grid and converted to Northern and Southern Hemisphere and tropical belt map bases are displayed and discussed.