• Aikman III, F., , H. W. Ou, , and R. W. Houghton, 1988: Current variability across the New England continental shelf-break and slope. Cont. Shelf Res., 8 , 625651.

    • Search Google Scholar
    • Export Citation
  • Austin, J. A., , and S. J. Lentz, 1999: The relationship between synoptic weather systems and meteorological forcing on the North Carolina inner shelf. J. Geophys. Res., 104 , 1815918186.

    • Search Google Scholar
    • Export Citation
  • Beardsley, R. C., , and W. C. Boicourt, 1981: On estuarine and continental-shelf circulation in the Middle Atlantic Bight. Evolution of Physical Oceanography: Scientific Surveys in Honor of Henry Stommel, B. A. Warren and C. Wunsch, Eds., The MIT Press, 198–233.

    • 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. Phys. Oceanogr., 15 , 713748.

    • Search Google Scholar
    • Export Citation
  • Bigelow, H. B., 1933: Studies of the waters on the continental shelf, Cape Cod to Chesapeake Bay, I, The cycle of temperature. Pap. Phys. Oceanogr. Meteor., 2 , 1135.

    • Search Google Scholar
    • Export Citation
  • Bigelow, H. B., , and M. Sears, 1935: Studies of the waters on the continental shelf, Cape Cod to Chesapeake Bay, II, Salinity. Pap. Phys. Oceanogr. Meteor., 4 , 194.

    • Search Google Scholar
    • Export Citation
  • Brink, K. H., , R. Limeburner, , and R. C. Beardsley, 2003: Properties of flow and pressure over Georges Bank as observed with near-surface drifters. J. Geophys. Res., 108 .8001, doi:10.1029/2001JC001019.

    • Search Google Scholar
    • Export Citation
  • Bumpus, D. F., 1973: A description of the circulation on the continental shelf of the east coast of the United States. Prog. Oceanogr., 6 , 111157.

    • Search Google Scholar
    • Export Citation
  • Butman, B., 1987: Processes causing surficial sediment movement. Georges Bank, R. H. Backus, Ed., The MIT Press, 147–162.

  • Butman, B., , and R. C. Beardsley, 1987: Long-term observations on the southern flank of Georges Bank. Part I: A description of the seasonal cycle of currents, temperature, stratification, and wind stress. J. Phys. Oceanogr., 17 , 367384.

    • Search Google Scholar
    • Export Citation
  • Codiga, D. L., 2005: Interplay of wind forcing and buoyant discharge off Montauk Point: Seasonal changes to velocity structure and a coastal front. J. Phys. Oceanogr., 35 , 10681085.

    • Search Google Scholar
    • Export Citation
  • Flagg, C. N., 1987: Hydrographic structure and variability. Georges Bank, R. H. Backus, Ed., The MIT Press, 108–124.

  • Flagg, C. N., , and M. Dunn, 2003: Characterization of the mean and seasonal flow regime on Georges Bank from shipboard acoustic Doppler current profiler data. J. Geophys. Res., 108 .8002, doi:10.1029/2001JC001257.

    • Search Google Scholar
    • Export Citation
  • Flagg, C. N., , M. Dunn, , D-P. Wang, , H. T. Rossby, , and R. L. Benway, 2006: A study of the currents of the outer shelf and upper slope from a decade of shipboard ADCP observations in the Middle Atlantic Bight. J. Geophys. Res., 111 .C06003, doi:10.1029/2005JC003116.

    • Search Google Scholar
    • Export Citation
  • Garvine, R. W., 2004: The vertical structure and subtidal dynamics of the inner shelf off New Jersey. J. Mar. Res., 62 , 337371.

  • Houghton, R. W., , R. Schlitz, , R. C. Beardsley, , B. Butman, , and J. L. Chamberlin, 1982: The Middle Atlantic Bight cold pool: Evolution of the temperature structure during summer, 1979. J. Phys. Oceanogr., 12 , 10191029.

    • Search Google Scholar
    • Export Citation
  • Isemer, H-J., , and L. Hasse, 1985: Observations. Vol. 1, The Bunker Climate Atlas of the North Atlantic Ocean, Springer-Verlag, 218 pp.

  • Kohut, J. T., , S. M. Glenn, , and R. J. Chant, 2004: Seasonal current variability on the New Jersey inner shelf. J. Geophys. Res., 109 .C07S07, doi:10.1029/2003JC001963.

    • Search Google Scholar
    • Export Citation
  • Large, W. G., , and S. Pond, 1981: Open ocean momentum flux measurements in moderate to strong winds. J. Phys. Oceanogr., 11 , 324336.

  • Lentz, S. J., 2008: Observations and a model of the mean circulation over the Middle Atlantic Bight continental shelf. J. Phys. Oceanogr., 38 , 12031221.

    • Search Google Scholar
    • Export Citation
  • Lentz, S. J., , R. T. Guza, , S. Elgar, , F. Feddersen, , and T. H. C. Herbers, 1999: Momentum balances on the North Carolina inner shelf. J. Geophys. Res., 104 , 1820518226.

    • Search Google Scholar
    • Export Citation
  • Lentz, S. J., , K. Shearman, , S. Anderson, , A. Plueddemann, , and J. Edson, 2003: The evolution of stratification over the New England shelf during the Coastal Mixing and Optics study, August 1996–June 1997. J. Geophys. Res., 108 .3008, doi:10.1029/2001JC001121.

    • 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 , 1840518423.

    • Search Google Scholar
    • Export Citation
  • Manning, J., 1991: Middle Atlantic Bight salinity: Interannual variability. Cont. Shelf Res., 11 , 123137.

  • Mayer, D. A., , D. V. Hansen, , and D. A. Ortman, 1979: Long-term current and temperature observation on the Middle Atlantic shelf. J. Geophys. Res., 84 , 17761792.

    • Search Google Scholar
    • Export Citation
  • Mountain, D. G., 2003: Variability in the properties of shelf water in the Middle Atlantic Bight, 1977–1999. J. Geophys. Res., 108 .3014, doi:10.1029//2001JC001044.

    • Search Google Scholar
    • Export Citation
  • Munchow, A., , and R. W. Garvine, 1993: Dynamical properties of a buoyancy-driven coastal current. J. Geophys. Res., 98 , 2006320078.

  • Noble, M., , B. Butman, , and E. Williams, 1983: On the longshore structure and dynamics of subtidal currents on the eastern United States continental shelf. J. Phys. Oceanogr., 13 , 21252147.

    • Search Google Scholar
    • Export Citation
  • Pawlowicz, R., , R. Beardsley, , and S. J. Lentz, 2002: Classical tidal harmonic analysis with errors in MATLAB using T_TIDE. Comput. Geosci., 28 , 929937.

    • Search Google Scholar
    • Export Citation
  • Rennie, S., , J. L. Largier, , and S. J. Lentz, 1999: Observations of low-salinity coastal current pulses downstream of Chesapeake Bay. J. Geophys. Res., 104 , 1822718240.

    • Search Google Scholar
    • Export Citation
  • Saunders, P. M., 1977: Wind stress on the ocean over the eastern continental shelf of North America. J. Phys. Oceanogr., 7 , 555566.

  • Shearman, R. K., , and S. J. Lentz, 2003: Dynamics of mean and subtidal flow on the New England shelf. J. Geophys. Res., 108 .3281, doi:10.1029/2002JC001417.

    • Search Google Scholar
    • Export Citation
  • Ullman, D. S., , and D. L. Codiga, 2004: Seasonal variation of a coastal jet in the Long Island Sound outflow region based on HF radar and Doppler current observations. J. Geophys. Res., 109 .C07S06, doi:10.1029/2002JC001660.

    • Search Google Scholar
    • Export Citation
  • Vickers, D., , L. Mahrt, , J. Sun, , and T. Crawford, 2001: Structure of offshore flow. Mon. Wea. Rev., 129 , 12511258.

  • Yankovsky, A. E., , R. W. Garvine, , and A. Munchow, 2000: Mesoscale currents on the inner New Jersey shelf driven by the interaction of buoyancy and wind forcing. J. Phys. Oceanogr., 30 , 22142230.

    • Search Google Scholar
    • Export Citation
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Seasonal Variations in the Circulation over the Middle Atlantic Bight Continental Shelf

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

Fits of an annual harmonic to depth-average along-shelf current time series longer than 200 days from 27 sites over the Middle Atlantic Bight (MAB) continental shelf have amplitudes of a few centimeters per second. These seasonal variations are forced by seasonal variations in the wind stress and the cross-shelf density gradient.

The component of wind stress that drives the along-shelf flow over most of the MAB mid- and outer shelf is oriented northeast–southwest, perpendicular to the major axis of the seasonal variation in the wind stress. Consequently, there is not a significant seasonal variation in the wind-driven along-shelf flow, except over the southern MAB shelf and the inner shelf of New England where the wind stress components forcing the along-shelf flow are north–south and east–west, respectively.

The seasonal variation in the residual along-shelf flow, after removing the wind-driven component, has an amplitude of a few centimeters per second with maximum southwestward flow in spring onshore of the 60-m isobath and autumn offshore of the 60-m isobath. The spring maximum onshore of the 60-m isobath is consistent with the maximum river discharges in spring enhancing cross-shelf salinity gradients. The autumn maximum offshore of the 60-m isobath and a steady phase increase with water depth offshore of Cape Cod are both consistent with the seasonal variation in the cross-shelf temperature gradient associated with the development and destruction of a near-bottom pool of cold water over the mid and outer shelf (“cold pool”) due to seasonal variations in surface heat flux and wind stress.

Corresponding author address: Steven J. Lentz, Woods Hole Oceanographic Institution, MS 21, Woods Hole, MA 02543. Email: slentz@whoi.edu

Abstract

Fits of an annual harmonic to depth-average along-shelf current time series longer than 200 days from 27 sites over the Middle Atlantic Bight (MAB) continental shelf have amplitudes of a few centimeters per second. These seasonal variations are forced by seasonal variations in the wind stress and the cross-shelf density gradient.

The component of wind stress that drives the along-shelf flow over most of the MAB mid- and outer shelf is oriented northeast–southwest, perpendicular to the major axis of the seasonal variation in the wind stress. Consequently, there is not a significant seasonal variation in the wind-driven along-shelf flow, except over the southern MAB shelf and the inner shelf of New England where the wind stress components forcing the along-shelf flow are north–south and east–west, respectively.

The seasonal variation in the residual along-shelf flow, after removing the wind-driven component, has an amplitude of a few centimeters per second with maximum southwestward flow in spring onshore of the 60-m isobath and autumn offshore of the 60-m isobath. The spring maximum onshore of the 60-m isobath is consistent with the maximum river discharges in spring enhancing cross-shelf salinity gradients. The autumn maximum offshore of the 60-m isobath and a steady phase increase with water depth offshore of Cape Cod are both consistent with the seasonal variation in the cross-shelf temperature gradient associated with the development and destruction of a near-bottom pool of cold water over the mid and outer shelf (“cold pool”) due to seasonal variations in surface heat flux and wind stress.

Corresponding author address: Steven J. Lentz, Woods Hole Oceanographic Institution, MS 21, Woods Hole, MA 02543. Email: slentz@whoi.edu

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