The Southern Ocean

Abstract

During the 50 years between 1925 and 1975, much effort was put into obtaining a large-scale, long-term average description of the Southern Ocean. Summaries of this description are generally presented as maps of dynamic height contours around the Southern Ocean to show the predominantly zonal circulation (Fig. 1) and as a schematic diagram of the circulation for a typical vertical-meridional section to show the meridional flux of water mass properties (Fig. 2). While such summaries are useful, they effectively suppress any temporal or small spatial scale variability and the suggested smoothness can be misleading. For example, the lack of small scale variability in these summaries perhaps led to two independent attempts to measure the transport of the Antarctic Circumpolar Current through Drake Passage with a few current meters deployed for a few days, which not surprisingly in view of later measurements of variability in the region produced transports differing by more than 250 × 10⁶ m³ s⁻¹ (Reid and Nowlin 1971, Foster 1972, Mann 1977). A useful summary of the large- scale descriptive effort of the last half-century in the Southern Ocean is provided by Gordon, Molinelli and Baker (1982).