Letter | Published:

Mid-depth recirculation observed in the interior Labrador and Irminger seas by direct velocity measurements

Nature volume 407, pages 6669 (07 September 2000) | Download Citation



The Labrador Sea is one of the sites where convection exports surface water to the deep ocean in winter as part of the thermohaline circulation. Labrador Sea water is characteristically cold and fresh, and it can be traced at intermediate depths (500–2,000 m) across the North Atlantic Ocean, to the south and to the east of the Labrador Sea1,2,3. Widespread observations of the ocean currents that lead to this distribution of Labrador Sea water have, however, been difficult and therefore scarce. We have used more than 200 subsurface floats to measure directly basin-wide horizontal velocities at various depths in the Labrador and Irminger seas. We observe unanticipated recirculations of the mid-depth (700 m) cyclonic boundary currents in both basins, leading to an anticyclonic flow in the interior of the Labrador basin. About 40% of the floats from the region of deep convection left the basin within one year and were rapidly transported in the anticyclonic flow to the Irminger basin, and also eastwards into the subpolar gyre. Surprisingly, the float tracks did not clearly depict the deep western boundary current, which is the expected main pathway of Labrador Sea water in the thermohaline circulation. Rather, the flow along the boundary near Flemish Cap is dominated by eddies that transport water offshore. Our detailed observations of the velocity structure with a high data coverage suggest that we may have to revise our picture of the formation and spreading of Labrador Sea water, and future studies with similar instrumentation will allow new insights on the intermediate depth ocean circulation.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    & Distribution and circulation of Labrador Sea Water. J. Phys. Oceanogr. 12, 1189–1205 (1982).

  2. 2.

    & N. Labrador Sea Water in the Eastern North Atlantic. Part I: A synoptic circulation inferred from a minimum in potential vorticity. J. Phys. Oceanogr. 25, 649–665 (1995).

  3. 3.

    et al. Surprisingly rapid spreading of newly formed intermediate waters across the North Atlantic Ocean. Nature 386, 675–679 (1997).

  4. 4.

    From the Labrador Sea to global change. Nature 386, 649–650 (1997).

  5. 5.

    , , , & Long-term coordinated changes in the convective activity of the North Atlantic. Prog. Oceanogr. 38, 241–295 (1996).

  6. 6.

    in Interactions Between Global Climate Subsystems, The Legacy of Hann (eds McBean, G. A. & Hantel, M.) 65–75 (American Geophysical Union, Washington DC, 1993).

  7. 7.

    & The formation of Labrador Sea Water. I. Large-scale processes. J. Phys. Oceanogr. 13, 1764–1778 (1983).

  8. 8.

    The renewal of Labrador Sea Water. Deep-Sea Res. 20 , 341–353 (1973).

  9. 9.

    Transport through the Cape Farewell–Flemish Cap section. Rapp. P.-v. Réun. Cons. Int. Explor. Mer. 185, 120–130 (1984).

  10. 10.

    & Annual velocity variations in the Labrador Current. J. Phys. Oceanogr. 23, 659–678 (1993).

  11. 11.

    Lab Sea Group. The Labrador Sea Deep Convection Experiment. Bull. Am. Meteorol. Soc. 79, 2033–2058 (1998).

  12. 12.

    , , & The autonomous Lagrangian circulation explorer (ALACE). J. Atmos. Ocean. Technol. 9, 264–285 (1992).

  13. 13.

    , & Profiling ALACEs and other advances in autonomous subsurface floats. J. Atmos. Oceanic Technol. (submitted).

  14. 14.

    Studies of Large-scale Intermediate and Deep Water Circulation and Ventilation in the North Atlantic, South Indian and Northeast Pacific Oceans, and in the East Sea (Sea of Japan), using Chlorofluorocarbons as Tracers. Thesis, Univ. California, San Diego (1999).

  15. 15.

    , , , & Eddies of newly formed upper Labrador Sea Water. J. Geophys. Res. 101, 20711–20726 (1996).

  16. 16.

    & Pathways of transport in the North Atlantic Current from surface drifters and subsurface floats. J. Geophys. Res. (submitted).

  17. 17.

    , & N. Mid-depth ventilation in the western boundary current system of the sub-polar gyre. Deep-Sea Res. 44, 1025–1054 (1997).

  18. 18.

    Evidence for large-scale eddy-driven gyres in the North Atlantic. Science 277, 361–364 ( 1997).

  19. 19.

    , & Spreading of Labrador Sea Water in the eastern North Atlantic. J. Geophys. Res. 103, 10223– 10239 (1998).

  20. 20.

    , & World Ocean Atlas 1994 Vol. 3, Salinity (NOAA Atlas NESDIS 3, US Department of Commerce, Washington, DC, 1994).

  21. 21.

    & World Ocean Atlas 1994 Vol. 4 , Temperature (NOAA Atlas NESDIS 4, US Department of Commerce, Washington DC, 1994).

Download references


We thank J. Dufour, J. Sherman, J. Valdes, R. Tavares and B. Guest for technical development and preparation of the floats, D. Newton and C. Wooding for help with data processing, and the numerous scientists who deployed the floats, often in adverse conditions at sea. This work was supported by the National Science Foundation, the Office of Naval Research, and the National Oceanic and Atmospheric Administration.

Author information


  1. *Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0230, USA

    • Kara L. Lavender
    •  & Russ E. Davis
  2. †Woods Hole Oceanographic Institution , Woods Hole, Massachusetts 02543, USA

    • W. Brechner Owens


  1. Search for Kara L. Lavender in:

  2. Search for Russ E. Davis in:

  3. Search for W. Brechner Owens in:

Corresponding author

Correspondence to Kara L. Lavender.

About this article

Publication history






Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.