Importance of wind-driven sea ice motion for the formation of Antarctic intermediate water in a global climate model

Abstract

An ocean-atmosphere-sea ice model is used to show the importance of wind-driven sea ice motion in the formation of Antarctic Intermediate Water (AAIW). The model is able to reasonably simulate a tongue of low salinity AAIW even when the direct momentum transfer from wind to the ocean is neglected, provided that the wind stress is applied to sea ice. In contrast, when the wind stress exclusively drives the ocean, the model fails to capture the properties of AAIW. The growth and subsequent offshore transport of sea ice acts as a freshwater conduit from nearshore regions, where AABW is formed, to subpolar regions, where AAIW is formed. Sea ice dynamics are also shown to be important in the simulation of a local salinity minimum at intermediate depths in the southern Indian Ocean and a local salinity maximum in the western Weddell Sea.