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The Antarctic coastal current in the southeastern Weddell Sea

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Summary

Between January and March 1989 during EPOS leg 3, a hydrographic survey was carried out in the southeastern Weddell Sea on transects across the continental shelf and slope off Kapp Norvegia and Halley Bay. This data set represents oceanographic conditions during Antarctic summer. Winter observations were obtained during the Winter Weddell Gyre Study in September and October 1989. During summer the water in the surface layer is relatively warm and of low salinity. In the area of Halley Bay exceptionally warm conditions were encountered with sea surface temperatures of nearly +1°C. Over the upper continental slope a frontal zone separates Eastern Shelf Water from Antarctic Surface Water in the near surface layer and from Warm Deep Water in the deeper layers. The horizontal pressure gradient associated with the front produces the high velocity core of the Antarctic Coastal Current. In winter Antarctic Surface Water is replaced by colder Winter Water of higher salinity. Measurements from current meters moored off Kapp Norvegia and Vestkapp are used to describe the mean features of the current field and its fluctuations. At Kapp Norvegia annual mean current speeds range from 10 to 20 cm/s. The geostrophic current shear indicates that the speed of the current core decreases towards Halley Bay. The currents show significant seasonal variations with strong interannual differences. These compare well with the variations of the wind field observed at the Georg von Neumayer Station. Superimposed are higher frequency fluctuations with an energetic range between 5 and 15 days which is found in the wind measurements as well. A considerable part of the current velocity variance is due to the tides. The oceanographic conditions are strongly influenced by the local bottom topography. A topographic rise at the shelf edge off Kapp Norvegia reduces horizontal advection and allows a patch of cold Winter Water to be preserved into the summer. In contrast, a patch of Warm Deep Water was found on the shelf of Halley Bay. This illustrates rather heterogeneous conditions in the near bottom layers due to differences in the exchange rate with the open ocean as well as with the near surface layers.

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References

  1. Arntz W, Ernst W, Hempel I (eds) (1990) The Expedition ANTAR-KTIS VII/4 (Epos leg 3) and VII/5 of RV “Polarstern” in 1989. Ber Polarforsch 68:1–214

  2. Augstein E, Bagriantsev N, Schenke HW (eds) (1991) The Expedition ANTARKTIS VII/1-2, 1989, with the Winter Weddell Gyre Study of the Research Vessels “Polarstern” and “Akademik Fedorov”. Ber Polarforsch 84:1–134

  3. Carmack EC (1974) A quantitative characterization of water masses in the Weddell Sea during summer. Deep-Sea Res 21:431–443.

  4. Carmack EC, Foster TD (1977) Water masses and circulation in the Weddell Sea. In: Dunbar MJ (ed) Polar oceans. Arct Inst North Am, pp 151–166

  5. Deacon GER (1937) The hydrography of the southern ocean. Discovery Rep 15:1–124

  6. Fahrbach E, Rohardt G (1988) Meteorological and oceanographic data of the winter Weddell Sea project 1986 (ANT V/3). Part 2. Moored instrument data. Ber Polarforsch 46:39–115

  7. Foremann MG (1978) Manual for tidal current analyses and prediction. Inst Ocean Sci Canada. Pac Mar Rep 78–6:1–70

  8. Foldvik A, Gammelsröd T, Törresen T (1985) Hydrographic observations from the Weddell Sea during the Norwegian Antarctic Research Expedition 1976/77. Polar Res 3:177–193

  9. Foster TD, Middleton JH (1979) Variability in the bottom water of the Weddell Sea. Deep-Sea Res 26:743–762

  10. Gill AE (1973) Circulation and bottom water formation in the Weddell Sea. Deep-Sea Res 20:11–140

  11. Gouretzky V, Danilov A (1992) Weddell Gyre: structure of the eastern boundary. Deep-Sea Res (in press)

  12. Olbers D (1991) The southern ocean and sea ice in climate — A review of modelling efforts. AWI Ber Fachb Phys 14:1–22

  13. Sverdrup HU (1954) The currents off the coast of Queen Maud Land. Nor Geogr Tidsskr 14:239–249

  14. Van Loon H (1967) The half-yearly oscillation in the middle and high southern latitudes and the coreless winter. J Atmos Sci 24:472–486

  15. Wamser C, Gube-Lenhardt M (1989) Klimatische Bedingungen an der Georg-von-Neumayer-Station in der Antarktis. Promet 1/2:1–7

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Data presented here were collected during the European Polarstern Study (EPOS) sponsored by the European Science Foundation

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Fahrbach, E., Rohardt, G. & Krause, G. The Antarctic coastal current in the southeastern Weddell Sea. Polar Biol 12, 171–182 (1992). https://doi.org/10.1007/BF00238257

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Keywords

  • Continental Shelf
  • Continental Slope
  • Oceanographic Condition
  • Horizontal Pressure Gradient
  • Hydrographic Survey