120
Baumann et al.
In the equatorial area, these two branches are separated by the South Equatorial Counter Current
(SECC), which moves surface-water eastward.
At about 100S off Brazil the SEC splits into two
branches, building the southward-flowing Brazil
Current (BC) and the northward-flowing North
Brazil Current (NBC) (Stramma and Peterson
1991). The latter contributes to the eastwards flowing North Equator Counter Current (NECC). Its
interaction with the northern branch of the SEC
lead to a strong convergence of water masses in
the mixing area at about 3° to SON. This results in
downwelling of surface-waters, which supports the
eastward flowing Equatorial Undercurrent (EUC).
The current occurs at a depth of 50 to 125m
w
-t~ ..
South
(peterson and Stramma 1991), is present along the
entire equator, and feeds surface currents off the
African coast. The contact zone ofEUC and SEC
forms the equatorial divergence where upwelling
of colder water from around the thermocline depth
occurs (Fig. 2b).
Thus, mean sea surface temperatures (SST)
are cooler at, and a little south of, the equator, and
warmest north of the equator, especially in the
western Atlantic. Strong seasonal variation in the
forcing winds, however, produces a fluctuating
equatorial system. In boreal summer SST in the
eastern equatorial Atlantic is at its minimum,
whereas in boreal winter, SST is at its annual maximum and part of the equatorial surface-water flows
Africa
Benguela Current system
;- "' :'
,,} .<
'".
. .
. ,
".' ,; ,
"
4 ; ; . / ,
"
.:. '-. ., Agulhas Current
N
s
Fig. 1. General surface-water circulation patterns in the South Atlantic (after Peterson and Stramma (1991).
Baumann et al.
In the equatorial area, these two branches are separated by the South Equatorial Counter Current
(SECC), which moves surface-water eastward.
At about 100S off Brazil the SEC splits into two
branches, building the southward-flowing Brazil
Current (BC) and the northward-flowing North
Brazil Current (NBC) (Stramma and Peterson
1991). The latter contributes to the eastwards flowing North Equator Counter Current (NECC). Its
interaction with the northern branch of the SEC
lead to a strong convergence of water masses in
the mixing area at about 3° to SON. This results in
downwelling of surface-waters, which supports the
eastward flowing Equatorial Undercurrent (EUC).
The current occurs at a depth of 50 to 125m
w
-t~ ..
South
(peterson and Stramma 1991), is present along the
entire equator, and feeds surface currents off the
African coast. The contact zone ofEUC and SEC
forms the equatorial divergence where upwelling
of colder water from around the thermocline depth
occurs (Fig. 2b).
Thus, mean sea surface temperatures (SST)
are cooler at, and a little south of, the equator, and
warmest north of the equator, especially in the
western Atlantic. Strong seasonal variation in the
forcing winds, however, produces a fluctuating
equatorial system. In boreal summer SST in the
eastern equatorial Atlantic is at its minimum,
whereas in boreal winter, SST is at its annual maximum and part of the equatorial surface-water flows
Africa
Benguela Current system
;- "' :'
,,} .<
'".
. .
. ,
".' ,; ,
"
4 ; ; . / ,
"
.:. '-. ., Agulhas Current
N
s
Fig. 1. General surface-water circulation patterns in the South Atlantic (after Peterson and Stramma (1991).