A COMPARATIVE-STUDY OF IMPLICIT AND EXPLICIT INITIALIZATION FOR A TROPICAL BAROTROPIC MODEL

The explicit nonlinear normal mode initialization (ENMI) scheme is app lied to a tropical barotropic limited area shallow water model in sphe rical coordinates. The model is formulated by considering potential en strophy conserving finite difference scheme. It is seen from the resul ts of this study that the ENMI scheme is fully capable of filtering ou t the spurious gravity wave oscillations. The results are compared wit h those using an implicit nonlinear normal mode initialization (INMI). The latter scheme gives equally satisfactory results, requiring less computational time than the explicit scheme.