Section SR1 across ACC choke point

The scientific plans of the World Ocean Circulation Experiment (WOCE) identified a number of sections, known as choke points where the meridional spread of the ACC is constrained and transport measurements can be attempted. One such section lies across Drake Passage (yellow dots above). The Drake Passage section is possibly the most important, because of its accessibility, because it is the narrowest, and because it provides the link between the Pacific and the Atlantic Oceans. For these reasons Drake Passage has also been designated as a repeat section — so that it should be occupied as often as possible. There remains an ongoing debate about whether or not warm surface water leaving the South Atlantic in a southward direction completes a circuit around Antarctica before returning north at greater depths, or whether there is a much shorter return path via the Southwest Indian Ocean: the difference between the so called cold-water path and warm-water path. Detailed measurements at Drake Passage will be crucial in the final resolution of this uncertainty.

The UK is currently established as the lead nation for the hydrography on this section. It is appropriate for us to take a lead in establishing a time series in the climate variability (CLIVAR) context. In addition to the hydrographic measurements undertaken by the Southampton Oceanography Centre (SOC) and British Antarctic Survey (BAS), UK research in Drake Passage includes the network of deep tide gauges maintained by the Proudman Oceanographic Laboratory (POL), analysis of satellite altimeter data at SOC, POL and the University of East Anglia (UEA), and state-of-the-art global numerical modelling at SOC and the Hadley Centre (part of the UK Met. Office) leads the world in coupled atmosphere-ocean climate modelling.

More information

Transport and variability of the Antarctic Circumpolar Current in Drake Passage
Time-series data (1993 - 2000)
Drake Passage transport over 25 years