• Davis, R. E., 1998: Preliminary results from directly measuring middepth circulation in the tropical and South Pacific. J. Geophys. Res., 103 ((C11),) 2461924639.

    • Search Google Scholar
    • Export Citation
  • Davis, R. E., , D. C. Webb, , L. A. Regier, , and J. Dufour, . 1992: The Autonomous Lagrangian Circulation Explorer (ALACE). J. Atmos. Oceanic Technol., 9 , 264284.

    • Search Google Scholar
    • Export Citation
  • Kearns, E. J., , and H. T. Rossby, 1998: Historical position of the North Atlantic Current. J. Geophys. Res., 103 ((C8),) 1550915524.

  • Krauss, W., 1986: The North Atlantic Current. J. Geophys. Res., 91 , 50615074.

  • Lab Sea Group, 1998: The Labrador Sea Deep Convection Experiment. Bull. Amer. Meteor. Soc., 79 , 20332058.

  • Lavender, K. L., , R. E. Davis, , and W. B. Owens, 2000: Mid-depth recirculation observed in the interior Labrador and Irminger Seas by direct velocity measurements. Nature, 407 , 6669.

    • Search Google Scholar
    • Export Citation
  • Lazier, J. R. N., 1988: Temperature and salinity changes in the deep Labrador Sea, 1962–1986. Deep-Sea Res., 35 , 12471253.

  • Lazier, J. R. N., , and D. G. Wright, 1993: Annual velocity variations in the Labrador Current. J. Phys. Oceanogr., 23 , 659678.

  • Lilly, J. M., , P. B. Rhines, , M. Visbeck, , R. Davis, , J. R. N. Lazier, , F. Schott, , and D. Farmer, 1999: Observing deep convection in the Labrador Sea during winter 1994/95. J. Phys. Oceanogr., 29 , 20652098.

    • Search Google Scholar
    • Export Citation
  • Molinari, R. L., , R. A. Fine, , W. D. Wilson, , R. G. Curry, , J. Abell, , and M. S. McCartney, 1998: The arrival of recently formed Labrador Sea Water in the Deep Western Boundary Current at 26.5°N. Geophys. Res. Lett., 25 , 22492252.

    • Search Google Scholar
    • Export Citation
  • Pickart, R. S., , and W. M. Smethie, 1998: Temporal evolution of the deep western boundary current where it enters the sub-tropical domain. Deep-Sea Res., 45 , 10531083.

    • Search Google Scholar
    • Export Citation
  • Reszka, M. K., , and G. E. Swaters, 1999: Eddy formation and interaction in a baroclinic frontal geostrophic model. J. Phys. Oceanogr., 29 , 30253042.

    • Search Google Scholar
    • Export Citation
  • Richardson, P. L., , and W. J. Schmitz, 1993: Deep cross-equatorial flow in the Atlantic measured with SOFAR floats. J. Geophys. Res., 98 , 83718387.

    • Search Google Scholar
    • Export Citation
  • Schott, F., , L. Stramma, , and J. Fischer, 1999: Interaction of the North Atlantic Current with the deep Charlie Gibbs Fracture Zone throughflow. Geophys. Res. Lett., 26 , 369372.

    • Search Google Scholar
    • Export Citation
  • Sy, A., , M. Rhein, , J. R. N. Lazier, , K. P. Koltermann, , J. Meincke, , A. Putzka, , and M. Bersch, 1997: Surprisingly rapid spreading of newly formed intermediate waters across the North Atlantic Ocean. Nature, 386 , 675679.

    • Search Google Scholar
    • Export Citation
  • Talley, L. D., , and M. S. McCartney, 1982: Distribution and circulation of Labrador Sea Water. J. Phys. Oceanogr., 12 , 11891205.

  • White, M. A., , and K. J. Heywood, 1995: Seasonal and interannual changes in the North Atlantic subpolar gyre from Geosat and TOPEX/Poseidon altimetry. J. Geophys. Res., 100 , 2493124941.

    • Search Google Scholar
    • Export Citation
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Labrador Sea Water Tracked by Profiling Floats—From the Boundary Current into the Open North Atlantic

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  • 1 Institut für Meereskunde an der Universität Kiel, Kiel, Germany
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Abstract

Fifteen profiling floats were injected into the deep boundary current off Labrador. They were ballasted to drift in the core depth of Labrador Sea Water (LSW) at 1500-m depth and were deployed in two groups during March and July/August 1997. Initially, for about three months, the floats were drifting within the boundary current, and the flow vectors were used to determine the mean horizontal structure of the Deep Labrador Current, which was found to be about 100 km wide with an average core speed of 18 cm s−1. North of Flemish Cap the boundary current encounters complicated topography around “Orphan Knoll,” and there the LSW outflow splits up into different routes. One obvious LSW path is eastward through the Charlie Gibbs Fracture Zone and another route is a narrow recirculation toward the central Labrador Sea. A surprising result was that none of the floats were able to follow the boundary current southward to the Grand Banks area and exit into the subtropics. Trajectories and temperature profiles of the eastward drifting floats indicate the importance of the North Atlantic Current for dispersing the floats, even at the level of LSW.

Corresponding author address: Dr. Jürgen Fischer, Institut für Meereskunde an der Universität Kiel, Düsternbrooker Weg 20, Kiel 24105, Germany. Email: jfischer@ifm.uni-kiel.de

Abstract

Fifteen profiling floats were injected into the deep boundary current off Labrador. They were ballasted to drift in the core depth of Labrador Sea Water (LSW) at 1500-m depth and were deployed in two groups during March and July/August 1997. Initially, for about three months, the floats were drifting within the boundary current, and the flow vectors were used to determine the mean horizontal structure of the Deep Labrador Current, which was found to be about 100 km wide with an average core speed of 18 cm s−1. North of Flemish Cap the boundary current encounters complicated topography around “Orphan Knoll,” and there the LSW outflow splits up into different routes. One obvious LSW path is eastward through the Charlie Gibbs Fracture Zone and another route is a narrow recirculation toward the central Labrador Sea. A surprising result was that none of the floats were able to follow the boundary current southward to the Grand Banks area and exit into the subtropics. Trajectories and temperature profiles of the eastward drifting floats indicate the importance of the North Atlantic Current for dispersing the floats, even at the level of LSW.

Corresponding author address: Dr. Jürgen Fischer, Institut für Meereskunde an der Universität Kiel, Düsternbrooker Weg 20, Kiel 24105, Germany. Email: jfischer@ifm.uni-kiel.de

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