 |
Figure 1.
The average ship-drift derived surface velocity plot
shows two major source regions for the Agulhas current:
(1) from the Mozambique channel to the north and along the coast; and
(2) from the east including a major contribution from
the Madagascar current. The average SST image shows the Agulhas current
bringing warm water poleward. On the average, the Agulhas current
retroflects and returns eastward with part of the flow recirculating in
the counter-clockwise flowing subtropical gyre and part of the flow
feeding the Antarctic Circumpolar Current. There is also a component of the
Agulhas current that feeds the Benguela current and advects relatively
warm and salty water into the South Atlantic as part of the Global
"conveyor belt" circulation.
Click here for example plots of
seasonal averages.
|
 |
Figure 2.
The average drifting buoy derived surface velocity.
Click here for example plots of
seasonal averages.
|
 |
Figure 3.
|
 |
Figure 4.
|
 |
Figure 5.
|
 |
Figure 6.
Buoy ID 03194, plotted in red for year 1996 and Buoy ID 23493,
plotted in blue for year 1997.
These trajectories of near-surface buoys illustrate
(1) the flow of central Indian ocean water into the Agulhas current;
(2) "looping" that indicates the drifters were in the energetic eddy field
of the Agulhas retroflection region and (3) the counter-clockwise flowing
subtropical gyre of the South Indian ocean. By comparing the trajectories
offshore of S. Africa and based on the ship-drift velocity estimates (Fig. 1),
it is evident that the core (fastest flow) of the Agulhas current is close
to shore. Note that Buoy 23493 drifted for over 800 km to the south and for
over 1000 km to the west from days 06/19 to 07/09.
|
 |
Figure 7.
Buoy ID 03194, plotted for the years 1994 to 1997 (blue, cyan, green and red).
In 1995 (cyan) the buoy drifts east/northeast in the Antarctic Circumpolar
Current/South Atlantic Current. Before it is about to be entrained into
the Benguela Current, the drifter is entrained into the outer core of a
large Agulhas ring for two "loops" and then flows eastward in the Agulhas
retroflection flow. In 1996 (green), the drifter is in the outer edge of
the Agulhas current flowing to the southwest along the African coast. In
1997 (red), after more than two years and two complete circuits of the gyre,
the drifter ends up in the center of an Agulhas ring being advected by the
Benguela Current.
|
 |
Figure 8.
AVRRR image of the sea-surface temperature (SST).
|
 |
Figure 9.
Geography of the region.
|
 |
Figure 10.
Topography/Bathymetry of the region.
|
