Experiments on Regional Forecasting Using a Stretched-Coordinate General Circulation Model

Abstract

The feasibility of regional forecasting using a stretched-coordinate global general circulation model is tested on a series of simulations of the 1979 summer monsoon onset, using enhanced resolution (or “zoom”) over the Indian Ocean area via a coordinate transform. It is found that the medium-to-long-range simulations are sensitive to the formulation of lateral diffusion and its dependency on grid size. The present experiments, performed at relatively coarse resolution, show definite improvement of the simulated circulation and precipitation features over the monsoon area in the medium range, du to the use of coordinate stretching.