• Bacmeister, J., and R. Pierrehumbert, 1988: On high-drag states of nonlinear stratified flow over an obstacle. J. Atmos. Sci.,45, 63–80.

  • Baines, P. G., 1995: Topographic Effects in Stratified Flows. Cambridge, 482 pp.

  • Bougeault, P., B. Benech, P. Bessemoulin, B. Carissimo, A. J. Clar, J. Pelon, M. Petitdidier, and E. Richard, 1997: PYREX: A summary of findings. Bull. Amer. Meteor. Soc.,78, 637–650.

  • Crawford, W. R., and R. K. Dewey, 1989: Turbulence and mixing: Sources of nutrients on the Vancouver Island continental shelf. Atmos.–Ocean,27, 428–442.

  • Dewey, R. K., and W. R. Crawford, 1988: Bottom stress estimates from vertical dissipation rate profiles on the continental shelf. J. Phys. Oceanogr.,18, 1167–1177.

  • ——, and J. N. Moum, 1990: Enhancement of fronts by vertical mixing. J. Geophys. Res.,95, 9433–9445.

  • Farmer, D. M., and R. A. Denton, 1985: Hydraulic control of flow over the sill in Observatory Inlet. J. Geophys. Res.,90 (C5), 9051–9068.

  • ——, and L. Armi, 1999a: The generation and trapping of solitary waves over topography. Science,283, 188–190.

  • ——, and ——, 1999b: Stratified flow over topography: The role of small scale entrainment and mixing in flow reestablishment. Proc. Roy. Soc. London,455A, 3221–3258.

  • Hunt, J. C. R., and W. H. Snyder, 1980: Experiments on stably and neutrally stratified flow over a model three-dimensional hill. J. Fluid Mech.,96 (4), 671–704.

  • Huyer, A. J., 1983: Coastal upwelling in the California Current system. Progress in Oceanography, Vol. 12, Pergamon Press, 259–284.

  • Ledwell, J. R., A. J. Watson, and C. S. Law, 1993: Evidence for slow mixing across the pycnocline from an open-ocean tracer-release experiment. Nature,364, 701–703.

  • Lueck, R. G., and T. R. Osborn, 1985: Turbulence measurements in a submarine canyon. Contin. Shelf Res.,4 (6), 681–698.

  • ——, and T. D. Mudge, 1997: Topographically induced mixing around a shallow seamount. Science,276, 1831–1833.

  • Moum, J. N., 1996: Efficiency of mixing in the main thermocline. J. Geophys. Res.,101 (C5), 12 057–12 069.

  • ——, M. C. Gregg, R. C. Lien, and M. E. Carr, 1995: Comparison of turbulence kinetic energy dissipation rate estimates from two ocean microstructure profilers. J. Atmos. Oceanic Technol.,12, 346–366.

  • Osborn, T. R., 1980: Estimates of the local rate of vertical diffusion from dissipation measurements. J. Phys. Oceanogr.,10, 83–89.

  • ——, and C. S. Cox, 1972: Oceanic fine structure. Geophys. Fluid Dyn.,3, 321–345.

  • Pillsbury, R., J. Bottero, R. Still, and W. Gilbert, 1974: A compilation of observations from moored current meters; Vol. iv; Oregon continental shelf; April-October 1972. Data Rep. 57, Oregon State University, Corvallis, OR, 126 pp. [Available from College of Oceanic and Atmospheric Sciences, Oregon State University, Ocean. Admin. Bldg. 104, Corvallis, OR 97331-5503.].

  • Toole, J. M., R. W. Schmitt, K. L. Polzin, and E. Kunze, 1997: Near-boundary mixing above the flanks of a midlatitude seamount. J. Geophys. Res.,102 (C1), 947–959.

  • Wesson, J. C., and M. C. Gregg, 1994: Mixing at Camarinal Sill in the Strait of Gibraltar. J. Geophys. Res.,99 (C5), 9847–9878.

  • Zülicke, C., E. Hagen, and A. Stips, 1998: Dissipation and mixing in a coastal jet: A Baltic Sea case study. Aquat. Sci.,60 (3), 220–235.

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Topographically Induced Drag and Mixing at a Small Bank on the Continental Shelf

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  • 1 College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon
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Abstract

Recent turbulence measurements over a small bank on the continental shelf off Oregon reveal a previously undetected site for intense mixing of the coastal ocean. The flow is hydraulically controlled and turbulence diffusivities over the bank are more than 100 times greater than estimates made on the shelf away from topography. The total drag exerted by the bank on the flow field is a combination of bottom friction plus form drag (analogous to mountain drag) and is comparable to the Coriolis force. This drag is sufficient to decelerate the flow over the bank in a matter of hours.

Corresponding author address: Dr. Jim Moum, College of Oceanic and Atmospheric Sciences, Oregon State University, 104 Ocean Administration Building, Corvallis, OR 97331-5503.

Email: moum@oce.orst.edu

Abstract

Recent turbulence measurements over a small bank on the continental shelf off Oregon reveal a previously undetected site for intense mixing of the coastal ocean. The flow is hydraulically controlled and turbulence diffusivities over the bank are more than 100 times greater than estimates made on the shelf away from topography. The total drag exerted by the bank on the flow field is a combination of bottom friction plus form drag (analogous to mountain drag) and is comparable to the Coriolis force. This drag is sufficient to decelerate the flow over the bank in a matter of hours.

Corresponding author address: Dr. Jim Moum, College of Oceanic and Atmospheric Sciences, Oregon State University, 104 Ocean Administration Building, Corvallis, OR 97331-5503.

Email: moum@oce.orst.edu

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