A GLOBAL SPECTRAL MODEL WITH VARIABLE POLES AND ITS APPLICATION TO THE SHALLOW-WATER EQUATIONS

Since we find out that the global spectral model with trapezoidal truncation has higher resolution in high latitudes(polar cap)than in low latitudes,this paper presents a global spectral model with variable poles which can be located at the center of interested area.The transform methods from traditional global spectral model to the new model are given and applied to a shallow-water equation model.The control experiments for 72h predictions were carried out.The "northern pole" in the transformed model was located at 15°N, 135°E.And the results showed that the predictions of weather systems in the area around the "new pole"(the polar cap,latitudes 60°)were better than those by the traditional model and the root mean square errors were improved.