Hostname: page-component-cd9895bd7-hc48f Total loading time: 0 Render date: 2024-12-18T18:18:12.383Z Has data issue: false hasContentIssue false

Horizontal mixing in the sea due to a shearing current

Published online by Cambridge University Press:  28 March 2006

K. F. Bowden
Affiliation:
Oceanography Department, University of Liverpool

Abstract

In addition to the random processes described as horizontal turbulence, there are certain more regular processes which may contribute to horizontal mixing. One of these occurs in a shearing current, where the vertical gradient of velocity combined with vertical turbulent mixing leads to an effective diffusion in the horizontal direction. It is shown that this effect occurs in an alternating flow, such as a tidal current, as well as in a steady flow. In estuaries and coastal waters horizontal mixing by the shear effect may be associated with tidal currents, density currents or wind-driven currents. In each case the effective coefficient of horizontal diffusion, Kx or Ky, is inversely proportional to the coefficient of vertical eddy diffusion Kz. The occurrence of a stable gradient of density therefore increases the effective horizontal mixing very considerably. Results obtained from observations in the Mersey estuary and Irish Sea are compared with theoretical estimates of these effects.

Type
Research Article
Copyright
© 1965 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bowden, K. F. 1963 Int. J. Air. Wat. Poll. 7, 34356.
Bowden, K. F. 1964 Oceanography and Marine Biology: an Annual Review, 2, 1130.
Bowden, K. F. & Fairbairn, L. A. 1952 Proc. Roy. Soc. A, 214, 37192.
Bowles, P., Burns, R. H., Hudswell, F. & Whipple, R. T. P. 1958 Proc. 2nd Conf. Peaceful Uses of Atomic Energy, U. N. Geneva, 18, 37689.
Cartwright, D. E. 1961 J. Inst. Navig. 14, 13051.
Csanady, G. T. 1963 J. Fluid Mech. 17, 36084.
Defant, A. 1961 Physical Oceanography, vol. 1. Oxford: Pergamon Press.
Ekman, V. W. 1905 Ark. Mat. Astr. Fys. 2 (11).
Elder, J. W. 1959 J. Fluid Mech. 5, 54460.
Ichiye, T. 1962 J. Geophys. Res. 67, 321316.
Joseph, J. & Sendner, H. 1958 Deut. Hydrog. Z. 11, 4977.
Okubo, A. 1962 J. Oceanogr. Soc. Japan, 20th anniv. vol., pp. 286320.
Stommel, H. 1953 Sewage & Ind. Wastes, 25, 106571.
Taylor, G. I. 1953 Proc. Roy. Soc. A, 219, 186203.
Taylor, G. I. 1954 Proc. Roy. Soc. A, 223, 446468.
Van Veen, J. 1938 J. Cons. int. Explor. Mer, 13, 736.