Errors caused by incompatible wind and buoyancy forcing in the ocean general circulation models.

Abstract

The Geophysical Fluid Dynamics Laboratory Modular Ocean Model (GFDL MOM) is used to investigate the model difference between compatible and incompatible surface wind and buoyancy forcing. The atmosphere is a physical system in which surface wind and temperature fields are related, however in most ocean numerical models, the wind stress and buoyancy forcing are usually specified separately, i.e., no constraint between the surface wind stress and surface air temperature is considered. In reality, only one of these two fields can be prescribed in the atmosphere-driven ocean models. When the surface wind field is prescribed, the surface air temperature should be derived, and vice versa. If the two related fields are treated as totally independent in forcing the ocean models the results will be distorted. Since the model solutions depend upon the atmospheric forcing, it is important that we study the compatibility between the wind and buoyancy forcings and the effect which incompatibility might have on the ocean numerical models. This study shows that the surface wind and buoyancy forcing widely used in ocean numerical models are incompatible. Such an incompatibility results in 21 % error in the total northward transport of heat, 16% error in the total northward transport of salt, 25% error in v velocity, and 16% error in w velocity.