PROBLEMS OF NUMERICAL MODELING OF EQUATOR IAL DYNAMICS

Intercomparison experiment has been carried out with two different PE ocean numerical models constructed at LODYC (Paris) and INM (Moscow). The models have been applied to equatorial spin-up problem. The calcul ation results show that each model has its own specific structure of n umerical noise. The noise structure is connected with the discretizati on of the original equations. Saw-toothed perturbations in the souther n and northern parts of the ocean basin were generated for C-grid appr oximation (LODYC-molel). B-grid scheme (INM-model) is characterized by an artificial boundary layer along the coastline. The source of such type of noise structure is connected with the fact that PE approximati on leads to ''unnatural'' discretization of v- or p-equation problem. Some ways how to improve the numerical schemes for primitive equations are indicated. There are: lumping of Coriolis terms for C grid; high order accuracy approximation for B grid; utilization of combined grid schemes.