A Prediction Experiment with a Global Model of the Kurihara-Grid

Abstract

 A general circulation model with the global grid system proposed by Kurihara was used to make a two-week forecast. The general characteristics of the model are: 9 vertical levels, a grid interval of approximately 220 km, orography, land-sea distribution, radiation, water vapor and convective adjustment. Data were collected from various regional data centers, and the maps were analyzed manually. The predicted results are compared with independent predictions for each hemisphere, using a hemispheric model of stereographic mapping, and also compared with observed data, where available. On the whole, the model’s performance was somewhat inferior to that of a hemispheric model with comparable physics and grid resolution, due to excessive truncation error. Yet some advantage of the global prediction over the hemispherical predictions was recognized, particularly in the tropics and also in the middle latitudes. For example, it predicted the latitudinal position of the subtropical jet more correctly.