TESTS OF THE EFFECT OF GRID RESOLUTION IN A GLOBAL PREDICTION MODEL

Abstract

Kurihara and Holloway have proposed an integration scheme that offers advantages in the problems of geophysical fluid dynamics by rigorously conserving mass and energy. We have attempted to investigate the accuracy of the Kurihara and Holloway method by numerical experiments, applying it to a problem for which an approximate analytic solution is available. For the case in which the planetary wave number is 4, we find that with the equal-area grid and with a latitude grid spacing of 4.5°, the planetary wave is destroyed by truncation errors within 5 days. In order to achieve a solution with acceptable accuracy, in which the planetary wave character is retained for a minimum of 10 days, the grid spacing near the Pole has to be decreased by a factor of 9.