Mixing and stirring in the Southern Ocean

The vertical and horizontal mixing of waters within the ocean affects the Earth's climate because it controls the poleward transport of heat and carbon within the ocean, the structure of the large‐scale currents, and the character of water that upwells and interacts with the atmosphere. Particularly in the Southern Ocean, ocean general circulation models can show different behavior depending on the exact representation of mixing. To date, however, measurements of this mixing have not been available because of the remoteness and difficult working conditions in the Southern Ocean. The Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES) seeks to understand the regional importance of the Southern Ocean to global circulation by measuring large‐ and small‐scale mixing processes. In the ocean, water moves primarily along surfaces of constant potential density (isopycnals), but it can also mix and change density between these surfaces in what is known as diapycnal mixing. This experiment, a joint effort between U.S. and U.K. scientists, will begin fieldwork in early 2009.