On the Formation of Antarctic Intermediate and Bottom Water in Ocean General Circulation Models

Abstract

Abstract A series of coarse-resolution models were integrated with a view to determining the most appropriate representation of the largest-scale water masses formed in the Southern Ocean. In particular, it was hoped that the models could realistically simulate Antarctic Bottom and Intermediate Water. The ocean model employed has a global domain with a realistic approximation of the continental outlines and bottom bathymetry. The subgrid-scale variation of bottom bathymetry is removed by spatial averaging over each grid box. The annual mean forcing at the sea surface is derived from climatological fields of temperature, salinity, and wind stress. It is found that the salinity of shelf water in the Weddell and Ross seas is critical if the model is to appropriately simulate the world's intermediate and bottom water masses. If the surface layer is too fresh in the Weddell and Ross seas, any bottom water formed adjacent to Antarctica is significantly less dense than in the real ocean. Furthermore, surface wat...