SECTION 4 THE GLOBAL FLOW FIELD
276
0
500
1000
1500
2000
2500
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
DISTANCE (km)
PRESSURE (dbar)
18 0
1 8 0
1 8 0
18 0
180
180
2 0 0
20 0
20 0
2 0 0
2 0 0
2 0 0
22 0
2 2 0
22 0
22 0
22 0
240
2 4 0
260
260
280
28 0 300
320
320
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
LATITUDE (°S)
l lll l l l
l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l
OXYGEN
UCDW
STF
SAF
SAF
PF
PF
SF
SB
ASF
c
0
500
1000
1500
2000
2500
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
DISTANCE (km)
PRESSURE (dbar)
27 .1
27.3
2 7 .7
2 7 . 8
27.8
27 .9
2 8 . 1
28 .3
2 7 . 4
2 8
28
2 8
28 .2
2
8
.
2
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
LATITUDE (°S)
l lll l l l
l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l lll
γ n
STF
SAF
SAF
PF
PF
SF
SB
ASF
d
Fig 4.6.3. Continued
calculated from three hydrographic sections referenced to current meters used to ‘level’ the gauges
and so determine the absolute transport (Whitworth
et al., 1982). By resolving the narrow fronts of
the ACC, the ISOS measurements significantly
reduced the uncertainty in transport estimates of
the ACC. Nevertheless, the loss of two moorings
in the vicinity of the Subantarctic and Polar
Fronts, the discrepancy between direct and hydrographic estimates of the vertical shear, and the fact
that the current meter moorings were not coherent, mean that the transports may be subject to
somewhat more uncertainty than the error bar
quoted above would indicate.
Whitworth et al. (1982) and Whitworth (1983)
showed from ISOS measurements that the
barotropic variability was higher in frequency and
larger in magnitude than the baroclinic variability.
This observation, together with the similarity
between repeat sections across Drake Passage