The Southern Ocean (SO) is the most remote and the least understood of the world’s oceans, although it plays a crucial role in past and present climate state and changes. It is unique in being the only zonally unbounded ocean. For this reason, it is the major link by which water properties are exchanged among the other oceans. It is a region of large exchanges of heat, fresh-water, momentum and carbon between the ocean and the atmosphere. The large rate at which energy is locally imparted to the ocean by the strong westerly winds forces the Antarctic Circumpolar Current (ACC; Wunsh, 1998), which is the longest and strongest oceanic current on Earth.