This movie shows how the Agulhas Current changes over the three years of our Agulhas Current Time-series experiment (ACT) http://act.rsmas.miami.edu . The data comes from an in situ array of current meter moorings (A to G), and three current- and pressure-recording inverted echo sounders (P3-4 and P4-5) which were deployed across the Agulhas Current off the southeast coast of South Africa (the coast is at the origin, bathymetry of the continental shelf and slope in black).
Each frame of the movie shows a full-depth cross-section of the velocity field (in meters per second) of the Agulhas Current every 12 hours, from April 2010 to February 2013. The warm, poleward-flowing Agulhas Current is shown in yellow and red, with an equatorward undercurrent and offshore flows in blue. Along the bottom of the frame is a graph of the strength of the currents across the whole section, in terms of volume transport in Sverdrups (million meters cubed per second). In blue is the total (or net) transport and in green is only the poleward (or southwestward) transport. The red line in the transport graph steps through the transport time series along with the movie.
Notice that most of the time the Agulhas Current is attached to the African continental slope, with its core (strongest velocities) positioned over the shelf break and slope. However, occasionally the Current separates from the slope and is displaced over 100 km offshore, into deep water. These "events" represent solitary meanders of the Current and are thought to be linked upstream to Mozambique eddies and downstream to the formation of Agulhas Rings at the Agulhas retroflection south of Africa.
These ACT data have enabled us to determine that these meanders are not associated with changes in the strength of the Agulhas Current, but only with changes in its path. For more info visit: http://act.rsmas.miami.edu