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A seasonal cycle in the export of bottom water from the Weddell Sea


Dense water formed over the Antarctic continental shelf rapidly descends into the deep ocean where it spreads throughout the global ocean as Antarctic Bottom Water1,2. The coldest and most voluminous component of this water mass is Weddell Sea bottom water1,3,4,5,6,7. Here we present observations over eight years of the temperature and salinity stratification in the lowermost ocean southeast of the South Orkney Islands, marking the export of Weddell Sea bottom water. We observe a pronounced seasonal cycle in bottom temperatures, with a cold pulse in May/June and a warm one in October/November, but the timing of these phases varies each year. We detect the coldest bottom water in 1999 and 2002, whereas there was no cold phase in 2000. On the basis of current velocities and water mass characteristics, we infer that the pulses originate from the southwest Weddell Sea. We propose that the seasonal fluctuations of Weddell Sea bottom-water properties are governed by the seasonal cycle of the winds over the western margin of the Weddell Sea. Interannual fluctuations are linked to the variability of the wind-driven Weddell Sea gyre and hence to large-scale climate phenomena such as the Southern Annular Mode and El Niño/Southern Oscillation.

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Figure 1: Weddell Sea moorings.
Figure 2: Eight-year time series at mooring M2 and M3.
Figure 3: Bottom θ°C and salinity relationship at M2 and M3.
Figure 4: Weddell Sea wind and climate indices.


  1. Orsi, A. H., Johnson, G. C. & Bullister, J. L. Circulation, mixing, and production of Antarctic bottom water. Prog. Oceanogr. 43, 55–109 (1999).

    Article  Google Scholar 

  2. Legg, S. et al. Improving oceanic overflow representation in climate models: The gravity current entrainment climate process team. Bull. Am. Meteorol. Soc. 90, 657–670 (2009).

    Article  Google Scholar 

  3. Carmack, E. C. & Foster, T. D. On the flow of water out of the Weddell Sea. Deep Sea Res. 22, 711–724 (1975).

    Google Scholar 

  4. Fahrbach, E., Rohardt, G., Schröder, M. & Strass, V. Transport and structure of the Weddell Gyre. Ann. Geophys. 12, 840–855 (1994).

    Article  Google Scholar 

  5. Gordon, A. L. in Ocean, Ice, and Atmosphere: Interactions at the Antarctic Continental Margin 215–240 (Antarct. Res. Ser., eds Jacobs, S. S. & Weiss, R. F. Vol. 75, AGU, 1998).

  6. Meredith, M. et al. On the sources of Weddell Gyre Antarctic Bottom Water. J. Geophys. Res. 105, 1093–1104 (2000).

    Article  Google Scholar 

  7. Nicholls, K. W., Østerhus, S., Makinson, K., Gammelsrød, T. & Fahrbach, E. Ice-ocean processes over the continental shelf of the southern Weddell Sea, Antarctica: A review. Rev. Geophys. 47, RG3003 (2009).

    Article  Google Scholar 

  8. Johnson, G. C. Quantifying Antarctic bottom water and North Atlantic deep water volumes. J. Geophys. Res. 113, C05027 (2008).

    Google Scholar 

  9. Jacobs, S. S., Giulivi, C. F. & Mele, P. Freshening of the Ross Sea during the late 20th century. Science 297, 386–389 (2002).

    Article  Google Scholar 

  10. Rintoul, S. R. Rapid freshening of Antarctic bottom water formed in the Indian and Pacific oceans. Geophys. Res. Lett. 34, L06606 (2007).

    Article  Google Scholar 

  11. Jacobs, S. S. & Giulivi, C. F. Large multi-decadal salinity trends near the Pacific-Antarctic continental margin. J. Clim. 10.1175/2010JCLI3284.1 (in the press, 2010).

  12. Hellmer, H. H., Kauker, F. & Timmermann, R. Weddell Sea anomalies: Excitation, propagation, and possible consequences. Geophys. Res. Lett. 36, L12605 (2009).

    Article  Google Scholar 

  13. Foster, T. D., Foldvik, A. & Middleton, J. H. Mixing and bottom water formation in the shelf break region of the southern Weddell Sea. Deep Sea Res. 34, 1771–1794 (1987).

    Article  Google Scholar 

  14. Gordon, A. L., Visbeck, M. & Huber, B. Export of Weddell Sea deep and bottom water. J. Geophys. Res. 106, 9005–9017 (2001).

    Article  Google Scholar 

  15. Huhn, O. et al. Evidence of deep and bottom water formation in the western Weddell Sea. Deep Sea Res. II 55, 1098–1116 (2008).

    Article  Google Scholar 

  16. Orsi, A. H. & Whitworth, T. III in Southern Ocean Vol. 1 (Hydrographic Atlas of the World Ocean Circulation Experiment (WOCE) (eds Sparrow, M., Chapman, P. & Gould, J.), Int. World Ocean Circ. Exp. Proj. Off., 2005).

  17. Gordon, A. L. et al. in Western Ross Sea Continental Slope Gravity Currents. Deep-Sea Res. Part II 56 (Special issue on Southern Ocean Shelf Slope Exchange, (eds Gordon, A., Padman, L. & Bergamasco, A.)), 796–817 (2009).

  18. Heywood, K. J. & King, B. A. Water masses and baroclinic transports in the South Atlantic and Southern oceans. J. Mar. Res. 60, 639–676 (2002).

    Article  Google Scholar 

  19. Mensch, M, Bayer, R., Bullister, J., Schlosser, P. & Weiss, R. The distribution of tritium and CFCs in the Weddell Sea during the mid-1980s. Prog. Oceanogr. 38, 377–415 (1996).

    Article  Google Scholar 

  20. Ackley, S. F., Geiger, C. A., King, J. C., Hunke, E. C. & Comiso, J. The Ronne Polynya of 1997/98: Observations of air–ice–ocean interaction. Ann. Glaciol. 33, 425–429 (2001).

    Article  Google Scholar 

  21. Timmermann, R., Hellmer, H. H. & Beckmann, A. Simulations of ice-ocean dynamics in the Weddell Sea 2, Interannual variability 1985–1993. J. Geophys. Res. 107, 3025 (2002).

    Article  Google Scholar 

  22. Lefebvre, W., Goosse, H., Timmermann, R. & Fichefet, T. Influence of the Southern annular mode on the sea ice-ocean system. J. Geophys. Res. 109, C09005 (2004).

    Article  Google Scholar 

  23. Visbeck, M. A station-based southern annular mode index from 1884 to 2005. J. Clim. 22, 940–995 (2009).

    Article  Google Scholar 

  24. Hall, A. & Visbeck, M. Synchronous variability in the Southern Hemisphere, sea ice, and ocean resulting from the annular mode. J. Clim. 15, 3043–3057 (2002).

    Article  Google Scholar 

  25. Gordon, A. L., Visbeck, M. & Comiso, J. C. A possible link between the Weddell Polynya and the Southern annular mode. J. Clim. 20, 2558–2571 (2007).

    Article  Google Scholar 

  26. Yuan, X. ENSO-related impacts on Antarctic sea ice: A synthesis of phenomenon and mechanisms. Antarctic Sci. 16, 415–425 (2004).

    Article  Google Scholar 

  27. Yuan, X. & Martinson, D. G. Antarctic sea-ice extent variability and its global connectivity. J. Clim. 13, 1697–1717 (2000).

    Article  Google Scholar 

  28. Simmonds, I. & King, J. C.. Global and hemispheric climate variations affecting the Southern ocean. Antarctic Sci. 16, 401–413 (2004).

    Article  Google Scholar 

  29. Stammerjohn, S. E., Martinson, D. G., Smith, R. C., Yuan, X. & Rind, D. Trends in Antarctic annual sea ice retreat and advance and their relation to El Niño-Southern oscillation and Southern annular mode variability. J. Geophys. Res. 108, C03S90 (2008).

    Google Scholar 

  30. Rintoul, S. et al. in Proc. of OceanObs’09: Sustained Ocean Observations and Information for Society, Venice, Italy, 21–25 September 2009 Vol. 2 (eds Hall, J., Harrison, D. E. & Stammer, D.) (ESA Publication WPP-306, 2010).

    Google Scholar 

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This research was financially supported under the Cooperative Institute for Climate Applications Research award number NA08OAR4320754 from the National Oceanic and Atmospheric Administration, U.S. Department of Commerce. The statements, findings, conclusions and recommendations are those of the author(s) and do not necessarily reflect the views of the National Oceanic and Atmospheric Administration or the Department of Commerce. Lamont Doherty Contribution number 7369.

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A.L.G. led the data analysis and leads the data collection programme. B.H. supervised the collection and processing of the data reported, and prepared the Methods section. D.M. investigated the relation of the Weddell Sea wind. M.V. contributed to the SAM discussion and was instrumental in the initiation of the Weddell time series.

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Correspondence to Arnold L. Gordon.

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Gordon, A., Huber, B., McKee, D. et al. A seasonal cycle in the export of bottom water from the Weddell Sea. Nature Geosci 3, 551–556 (2010).

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