• Bacon, S., 1998: Decadal variability in the outflow from the Nordic Seas to the deep Atlantic Ocean. Nature,394, 871–874.

  • Clarke, R. A., H. W. Hill, R. F. Reiniger, and B. A. Warren, 1980: Current system south and east of the Grand Banks of Newfoundland. J. Phys. Oceanogr.,10, 25–65.

  • Collins, J. W., 1884: History of the tilefish. U.S. Commn. on Fish and Fisheries, Rep. Commissioner V(1882), 237–294.

  • Csanady, G. T., and P. Hamilton, 1988: Circulation of slopewater. Contin. Shelf Res.,8, 565–624.

  • Curry, R. G., M. S. McCartney, and T. M. Joyce, 1998: Oceanic transport of subpolar climate signals to middepth subtropical waters. Nature,391, 575–577.

  • Dickson, R. R., J. R. N. Lazier, J. Meincke, P. B. Rhines, and J. Swift, 1996: Long-term coordinated changes in the convective activity of the North Atlantic. Progress in Oceanography, Vol. 38, Pergamon, 241–295.

  • Fofonoff, N. P., and M. M. Hall, 1983: Estimates of mass, momentum, and kinetic energy fluxes of the Gulf Stream. J. Phys. Oceanogr.,13, 1868–1877.

  • Fuglister, F. C., 1963: Gulf Stream ‘60. Progress in Oceanography, Vol. 1, Pergamon, 265–383.

  • ——, and L. V. Worthington, 1951: Some results of a multiple ship survey of the Gulf Stream. Tellus,3, 1–14.

  • Hendry, R., 1993: Currents south of the Grand Banks at 50W: Estimates of mass transport. The North Atlantic Current System: A Scientific Report, Rizzoli and T. Rossby, Eds., 132 pp.

  • ICES, 1995: Report of the Cod and Climate Backward-Facing Workshop. Bedford Institute of Oceanography, Dartmouth, NS, Canada, 8-ICES, 23 pp.

  • Lazier, J. R. N., and D. G. Wright, 1993: Annual velocity variations in the Labrador Current. J. Phys. Oceanogr.,23, 559–678.

  • Linder, C. A., and G. G. Gawarkiewicz, 1998: A climatology of the Shelfbreak Front in the Middle Atlantic Bight. J. Geophys. Res.,103, 18 405–18 423.

  • Loder, J. W., B. Petrie, and G. Gawarkiewicz, 1998: The coastal ocean off northeastern North America: A large-scale view. The Sea, Coastal Segment I, A. Robinson and K. Brink, Eds., Vol. 11, 105–133.

  • Mann, C. R., 1967: The termination of the Gulf Stream and the beginning of the North Atlantic Current. Deep-Sea Res.,14, 337–359.

  • McLellan, H. J., 1957: On the distinctness and origin of the slope water off the Scotian shelf and its easterly flow south of the Grand Banks. Fish. Res. Bd. Canada,14, 213–239.

  • Mountain, D. G., and J. L. Shuhy, 1980: Circulation near the Newfoundland Ridge. J. Mar. Res.,38, 205–213.

  • Myers, R. A., J. Helbig, and D. Holland, 1989: Seasonal variability of the Labrador Current and West Greenland Current. Paper C.M. 1989/c:16, ICES, 10 pp.

  • Petrie, B., and K. Drinkwater, 1993: Temperature and salinity variability on the Scotian Shelf and in the Gulf of Maine 1945–1990. J. Geophys. Res.,98, 20 079–20 089.

  • Pickart, R. S., 1992: Space–time variability of the deep western boundary current oxygen core. J. Phys. Oceanogr.,22, 1047–1061.

  • ——, and W. M. Smethie Jr., 1993: How does the deep western boundary current cross the Gulf Stream? J. Phys. Oceanogr.,23, 2602–2616.

  • ——, and R. X. Huang, 1995: Structure of an inertial deep western boundary current. J. Mar. Res., 53, 739–770.

  • ——, and ——, 1998: Temporal evolution of the Deep Western Boundary Current where it enters the sub-tropical domain. Deep-Sea Res.,45, 1053–1083.

  • ——, M. A. Spall, and J. R. N. Lazier, 1997: Mid-depth ventilation in the western boundary current system of the sub-polar gyre. Deep-Sea Res.,44, 1025–1054.

  • Richardson, P. L., 1985: Average velocity and transport of the Gulf Stream near 55W. J. Mar. Res.,43, 83–111.

  • Worthington, L. V., 1976: On the North Atlantic Circulation. The Johns Hopkins Oceanographic Studies, No. 6, 110 pp.

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Mean Structure and Interannual Variability of the Slopewater System South of Newfoundland

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  • 1 Woods Hole Oceanographic Institution, Woods Hole, Massachusetts
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Abstract

Two sets of repeat hydrographic sections, centered at 55°W and 50°W, are used to study the mean features and long-term variability of the slopewater system south of Newfoundland, inshore of the Gulf Stream. The upper-layer flow is considered first, consisting of the westward-flowing Labrador Current at the shelfbreak (input into the slopewater system) and the eastward-flowing slopewater current over midslope (export out of the slopewater system). Particular attention is paid to the slopewater current, as this is a less well-known feature. The velocity structure of the slopewater current is different at the two longitudes, associated with a change in structure of the density front. Its mean transport is found to be significantly less than historical estimates. Both the lateral position and the strength of the current vary on long timescales. These fluctuations are correlated with the variability of the Labrador Current, as well as with changes in the deeper components of the slopewater (the Labrador Sea Water and Denmark Strait overflow water). The general picture that emerges is that the entire upper-layer slopewater circulation spins up/down on interannual timescales, coincident with strengthening/weakening of the overflow component of the deep western boundary current. Interestingly, more undiluted Labrador Sea Water is present in the spundown state.

Corresponding author address: Dr. Robert S. Pickart, Woods Hole Oceanographic Institution, Woods Hole, MA 02543.

Email: rpickart@whoi.edu

Abstract

Two sets of repeat hydrographic sections, centered at 55°W and 50°W, are used to study the mean features and long-term variability of the slopewater system south of Newfoundland, inshore of the Gulf Stream. The upper-layer flow is considered first, consisting of the westward-flowing Labrador Current at the shelfbreak (input into the slopewater system) and the eastward-flowing slopewater current over midslope (export out of the slopewater system). Particular attention is paid to the slopewater current, as this is a less well-known feature. The velocity structure of the slopewater current is different at the two longitudes, associated with a change in structure of the density front. Its mean transport is found to be significantly less than historical estimates. Both the lateral position and the strength of the current vary on long timescales. These fluctuations are correlated with the variability of the Labrador Current, as well as with changes in the deeper components of the slopewater (the Labrador Sea Water and Denmark Strait overflow water). The general picture that emerges is that the entire upper-layer slopewater circulation spins up/down on interannual timescales, coincident with strengthening/weakening of the overflow component of the deep western boundary current. Interestingly, more undiluted Labrador Sea Water is present in the spundown state.

Corresponding author address: Dr. Robert S. Pickart, Woods Hole Oceanographic Institution, Woods Hole, MA 02543.

Email: rpickart@whoi.edu

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