Physical oceanography data from
with antarctic bottom water formation considered to be active in the western perimeter of the Weddell gyre and near the gyre center just to the west of Maud Rise. The warm-saline deep water is advected to the west of Maud Rise along the antarctic continental slope, which requires a sudden poleward offset of this water mass at Maud Rise. Of interest is the role that Maud Rise might play in the initiation of this offset and the consequences in regard to bottom water formation. Another fascinating relation is that the Pacific bottom water source of the Weddell warmdeep water is enriched in salt (relative to water of similar
temperatures elsewhere in the circumpolar belt), by the Ross Sea saline bottom water. This raises the question: Is the convective process believed common in the Weddell Sea preconditioned by the Ross Sea? Another topic being studied is the open ocean convection of the Weddell gyre. Convective processes may be responsible for the rapid early spring melting of sea ice cover, and in its more extreme mode may induce the Weddell Polynya (open water) feature in the winter period. This research is supported by National Science Foundation grant DPP 78-24832.
Physical oceanography data from ARA Islas Orcadas cruise 17-78
The austral winter cruise of ARA Islas Orcadas cruise 17-78 took place from 2 September to 14 October 1978, mainly to obtain biological data related to primary productivity along the pack ice during the late austral winter. In order to determine physical oceanographic conditions, 19 salinitytemperature-depth (STD) stations with rosette samplers were occupied and 117 expendable bathythermographs (xsi"s) were launched during the cruise (figure 1). The std data were processed by correcting temperature and salinity with formulas obtained by comparing with values
TAKASHI ICHIYE
and
MASAMICHI INOUE
Department of Oceanography Texas A&M University College Station, Texas 77843
750
500
550
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350
45'
25'
395
38• \ XII FALKLAND ISLANDS
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SOUTH GEORGIA
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600
SOUTH ORKNEY ISLANDS SOUTH SHETLAND ISLANDS, SID O XBT
0
0
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65'
550
Figure 1. Location of sic stations (in open circles) and of cruise 17-78.
90
XBT
450
350
250
stations (in closed circles) occupied during ARA Islas Orcadas
ANTARCr!C JOURNAL
determined with reversing thermometers and salinometers the Antarctic Front, temperature reached above 5°C and from rosette samples. These data, with 71 XBT tracings, were 2.5° to 4.5°C in the upper 200 meters in section I and section digitized and tabulated. At each station, temperature and II, respectively, whereas to the south temperature was besalinity profiles with su and xwr were prepared. Vertical low — 1°C and 0.50 to 1°C in section I and section II, resections of temperature, salinity, sigma-t and geostrophic spectively. Also, the northern stations 5, 6, 37, 38, and 39 velocity were constructed for two transects through the showed surface warming of about 0.2 0 to 0.4°C in the upDrake Passage (section I, figure 2) and the South Georgian per 20 meters with a particularly sharp temperature inBasin (section II, figure 3) (Inoue and Ichiye 1980). crease at station 39. Preliminary analysis indicates that the Antarctic Front was located between stations 6 and 7 in section 1 and be- Reference tween stations 37 and 36 in section II with highest geostrophic speed of 62 centimeters/ second based on 2,000- Inoue, M., and Ichiye, T. 1980. Report of physical oceanography data decibar reference level in section I and 20 centimeters/ on ARA Islas Orcadas cruise 17-78. College Station: Texas A & M second based on 1,500-decibar level in section II. North of University, Department of Oceanography. 136 pp. ITDm
S
(0) 56 3,0 Long)tod (9) 60 1 .7
8
a756.6 07 3.2 06 43.7 58 59130 58 51.9 56 12.7
9
4
47
0. 4)
50
100
11W
200
.4
Figure 2. Temperature cross section across the Drake Passage with sm stations.
4)
Distance Along Transect (Km) Vertical Cross-Section of Temperature (°C)
0. 4) 0
1W
ZW
250
3W
350
400
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5W
5W
606
Distance Along Transect (Km) Vertical Cross-Section of Temperature (°C) Figure 3. Temperature cross section in the South Georgian Basin with sio stations.
1980 REVIEW
91
