• Aikman, F. I. I. I., , H. W. Ou, , and R. W. Houghton, 1988: Current variability across the New England continental shelfbreak and slope. Contin. Shelf Res, 8 , 625651.

    • Search Google Scholar
    • Export Citation
  • Barth, J. A., , D. Bogucki, , S. D. Pierce, , and P. M. Kosro, 1998: Secondary circulation associated with a shelfbreak front. Geophys. Res. Lett, 25 , 27612764.

    • Search Google Scholar
    • Export Citation
  • Beardsley, R. C., , and C. N. Flagg, 1976: The water structure, mean currents, and shelf-water/slopewater front on the New England continental shelf. Mem. Soc. Roy. Sci. Liege, 6 , 209225.

    • Search Google Scholar
    • Export Citation
  • Beardsley, R. C., , D. C. Chapman, , K. H. Brink, , S. R. Ramp, , and R. Schlitz, 1985:: The Nantucket Shoals Flux Experiment (NSFE79). Part I: A basic description of the current and temperature variability. J. Phy. Oceanogr, 15 , 713748.

    • Search Google Scholar
    • Export Citation
  • Burrage, D. M., , and R. W. Garvine, 1987: Supertidal frequency internal waves on the continental shelf south of New England. J. Phys. Oceanogr, 17 , 808819.

    • Search Google Scholar
    • Export Citation
  • Chapman, D. C., , and R. C. Beardsley, 1989: On the origin of shelf water in the Middle Atlantic Bight. J. Phys. Oceanogr, 19 , 384391.

  • Chapman, D. C., , and S. J. Lentz, 1994: Trapping of a coastal density front by the bottom boundary layer. J. Phys. Oceanogr, 24 , 14641479.

    • Search Google Scholar
    • Export Citation
  • Flagg, C. N., , and B. C. Beardsley, 1978: On the stability of the shelf water/slope-water front south of New England. J. Geophys. Res, 83 , 46234631.

    • Search Google Scholar
    • Export Citation
  • Foreman, M. G. G., 1978: Manual for tidal currents analysis and prediction (revised 1996). Pacific Marine Science Rep. 78-6, Institute of Ocean Sciences, Patricia Bay, Sidney, BL, Canada, 57 pp.

    • Search Google Scholar
    • Export Citation
  • Galbraith, N., , A. Phreddemann, , S. Lentz, , S. Anderson, , M. Baumgartner, , and J. Edson, 1999: Coastal Mixing and Optics Experiment moored arrray data report. Woods Hole Oceanographic Institution Rep. WHOI-99-15, 156 pp.

    • Search Google Scholar
    • Export Citation
  • Garrett, C., 1972: Tidal resonance in the Bay of Fundy and Gulf of Maine. Nature, 238 , 441443.

  • Garvine, R. W., , K-C. Wong, , G. G. Gawarkiewicz, , R. K. McCarthy, , R. W. Houghton, , and F. Aikman III, 1988: The morphology of shelfbreak eddies. J. Geophys. Res, 93 , 15 59315 607.

    • Search Google Scholar
    • Export Citation
  • Gawarkiewicz, G., 1991: Linear stability models of shelfbreak fronts. J. Phys. Oceanogr, 21 , 471488.

  • Gawarkiewicz, G., , and D. C. Chapman, 1992: The role of stratification in the formation and maintenance of shelf-break fronts. J. Phys. Oceanogr, 22 , 753772.

    • Search Google Scholar
    • Export Citation
  • Gawarkiewicz, G., , T. G. Ferdelman, , T. M. Church, , and G. W. Luther III, 1996: Shelfbreak frontal structure on the continental shelf north of Cape Hatteras. Contin. Shelf Res, 16 , 17511773.

    • Search Google Scholar
    • Export Citation
  • Gawarkiewicz, G., , F. Bahr, , R. C. Beardsley, , and K. H. Brink, 2001: Interaction of a slope eddy with the shelfbreak front in the Middle Atlantic Bight. J. Phys. Oceanogr., in press.

    • Search Google Scholar
    • Export Citation
  • Gill, A. E., 1982: Atmosphere–Ocean Dynamics. Academic Press, 662 pp.

  • Halkin, D., , and T. Rossby, 1985: The structure and transport of the Gulf Stream at 73°W. J. Phys. Oceanogr, 15 , 14391452.

  • Halliwell, G. R., , and C. N. K. Mooers, 1979: The space–time structure and variability of the shelf water–slope water and Gulf Stream surface temperature fronts and associated warm-core eddies. J. Geophys. Res, 84 , 77077725.

    • Search Google Scholar
    • Export Citation
  • Houghton, R. W., 1997: Lagrangian flow at the foot of a shelfbreak front using a dye tracer injected into the bottom boundary layer. Geophys. Res. Lett, 24 , 20352038.

    • Search Google Scholar
    • Export Citation
  • Houghton, R. W., , and M. Visbeck, 1998: Upwelling and convergence in the Middle Atlantic Bight shelf break front. Geophys. Res. Lett, 25 , 27652768.

    • Search Google Scholar
    • Export Citation
  • Houghton, R. W., , D. B. Olson, , and P. J. Celone, 1986: Observation of an anticyclonic eddy near the continental shelfbreak south of New England. J. Phys. Oceanogr, 16 , 6071.

    • Search Google Scholar
    • Export Citation
  • Houghton, R. W., , F. Aikman III, , and H. W. Ou, 1988: Shelf–slope frontal structure and cross-shelf exchange at the New England shelfbreak. Contin. Shelf Res, 8 , 687710.

    • Search Google Scholar
    • Export Citation
  • Joyce, T. M., , J. K. B. Bishop, , and O. B. Brown, 1992: Observations of offshore shelf water transport induced by a warm-core ring. Deep-Sea Res, 39A (Suppl. 1) , S97S113.

    • Search Google Scholar
    • Export Citation
  • Linder, C. A., , and G. Gawarkiewicz, 1998: A climatology of the shelfbreak front in the Middle Atlantic Bight. J. Geophys. Res, 103 , 18 40518 423.

    • Search Google Scholar
    • Export Citation
  • Loder, J. W., , B. Petrie, , and G. Gawarkiewicz, 1998: The coastal ocean off northeastern North America. A large-scale view. The Sea, A. R. Robinson and K. H. Brink, Eds., 105–133 pp.

    • Search Google Scholar
    • Export Citation
  • Lozier, S., , and G. Gawarkiewicz, 2001: Cross-frontal exchange in the Mid-Atlantic Bight as evidenced by surface drifters. J. Phys. Oceanogr, 31 , 24982551.

    • Search Google Scholar
    • Export Citation
  • Lozier, S., , M. S. C. Reed, , and G. Gawarkiewicz, 2001: Instability of a shelfbreak front. J. Phys. Oceanogr., submitted.

  • Moody, J. A., and and Coauthors, 1984: Atlas of tidal elevation and current observations on the northeast American continental shelf and slope. U. S. Geological Survey Bulletin, No. 1611, 122 pp.

    • Search Google Scholar
    • Export Citation
  • 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 07920 089.

    • Search Google Scholar
    • Export Citation
  • Pickart, R. S., 2000: Bottom boundary layer structure and detachment in the shelfbreak jet of the Middle Atlantic Bight. J. Phys. Oceanogr, 30 , 26682686.

    • Search Google Scholar
    • Export Citation
  • Pickart, R. S., , T. K. Mckee, , D. J. Torres, , and S. A. Harrington, 1999a: Mean structure and interannual variability of the slopewater system south of Newfoundland. J. Phys. Oceanogr, 29 , 25412558.

    • Search Google Scholar
    • Export Citation
  • Pickart, R. S., , D. J. Torres, , T. K. Mckee, , M. J. Caruso, , and J. E. Przystup, 1999b: Diagnosing a meander of the shelfbreak current in the Middle Atlantic Bight. J. Geophys. Res, 104 , 31213132.

    • Search Google Scholar
    • Export Citation
  • Pollard, R. T., , and L. A. Regier, 1992: Vorticity and vertical circulation at an ocean front. J. Phys. Oceanogr, 22 , 609625.

  • Ramp, S. R., , R. C. Beardsley, , and R. Legeckis, 1983: An observation of frontal wave development on a shelf-slope/warm core ring front near the shelf break south of New England. J. Phys. Oceanogr, 13 , 907912.

    • Search Google Scholar
    • Export Citation
  • Twichell, D. C., , C. E. McClennen, , and B. Butman, 1981: Morphology and processes associated with the accumulation of the fine-grained sediment deposit on the southern New England shelf. J. Sediment. Petrol, 51 , 269280.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 144 144 7
PDF Downloads 20 20 3

Mean Structure and Dynamics of the Shelfbreak Jet in the Middle Atlantic Bight during Fall and Winter

View More View Less
  • 1 Department of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts
© Get Permissions Rent on DeepDyve
Restricted access

Abstract

Using a collection of high-resolution shipboard acoustic Doppler current profiler (ADCP) velocity sections that cross the Middle Atlantic Bight shelfbreak jet near 70°W, the mean structure of the frontal jet is described and the dominant modes of variability of the jet are examined. A mean section is constructed in a translating coordinate frame whose origin tracks the instantaneous position of the core of the jet, thereby minimizing variability associated with the lateral meandering of the current. The mean jet so constructed extends to the bottom, tilting onshore with depth, with near-bottom flow exceeding 0.10 m s−1. The corresponding cross-stream flow reveals a clear pattern of convergence that extends along the tilted axis of the jet, with enhanced convergence both near the surface and near the bottom. This convergence is largely attributed to the locally convergent topography and is shown to drive an ageostrophic circulation dominated by downwelling at, and offshore of, the jet core. The collection of ADCP sections also suggests a previously undetected mode of variability, whereby the jet systematically fluctuates between a convergent, bottom-reaching state and a surface-trapped state with weaker cross-stream velocities. This variability is associated with significant variations in the southwestward transport of the jet and does not seem to be related to simple meandering of the current.

 Current affiliation: Department of Marine Sciences, University of North Carolina, Chapel Hill, North Carolina.

Corresponding author address: P. S. Fratantoni, Physical Oceanography Dept., Woods Hole Oceanographic Institution, MS 21, Woods Hole, MA 02543.Email: pfratantoni@whoi.edu

Abstract

Using a collection of high-resolution shipboard acoustic Doppler current profiler (ADCP) velocity sections that cross the Middle Atlantic Bight shelfbreak jet near 70°W, the mean structure of the frontal jet is described and the dominant modes of variability of the jet are examined. A mean section is constructed in a translating coordinate frame whose origin tracks the instantaneous position of the core of the jet, thereby minimizing variability associated with the lateral meandering of the current. The mean jet so constructed extends to the bottom, tilting onshore with depth, with near-bottom flow exceeding 0.10 m s−1. The corresponding cross-stream flow reveals a clear pattern of convergence that extends along the tilted axis of the jet, with enhanced convergence both near the surface and near the bottom. This convergence is largely attributed to the locally convergent topography and is shown to drive an ageostrophic circulation dominated by downwelling at, and offshore of, the jet core. The collection of ADCP sections also suggests a previously undetected mode of variability, whereby the jet systematically fluctuates between a convergent, bottom-reaching state and a surface-trapped state with weaker cross-stream velocities. This variability is associated with significant variations in the southwestward transport of the jet and does not seem to be related to simple meandering of the current.

 Current affiliation: Department of Marine Sciences, University of North Carolina, Chapel Hill, North Carolina.

Corresponding author address: P. S. Fratantoni, Physical Oceanography Dept., Woods Hole Oceanographic Institution, MS 21, Woods Hole, MA 02543.Email: pfratantoni@whoi.edu

Save