A comparative study of implicit and explicit initialization for a tropical barotropic model

The explicit nonlinear normal mode initialization (ENMI) scheme is applied to a tropical barotropic limited area shallow water model in spherical coordinates. The model is formulated by considering potential enstrophy conserving finite difference scheme. It is seen from the results of this study that the ENMI scheme is fully capable of filtering out the spurious gravity wave oscillations. The results are compared with those using an implicit nonlinear normal mode initialization (INMI). The latter scheme gives equally satisfactory results, requiring less computational time than the explicit scheme.