Record Details

The role of the turbulent stress divergence in the equatorial Pacific zonal momentum balance

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Field Value
Title The role of the turbulent stress divergence in the equatorial Pacific zonal momentum balance
Names Hebert, D. (creator)
Moum, James N. (creator)
Paulson, C. A. (creator)
Caldwell, Douglas R. (creator)
Chereskin, T. K. (creator)
McPhaden, M. J. (creator)
Date Issued 1991-04-15 (iso8601)
Note Copyrighted by American Geophysical Union.
Abstract From a comprehensive set of upper ocean measurements made during a moderate El Niño in boreal spring 1987, we reassess the role of turbulence in transporting momentum vertically at the equator. An examination of the terms in the vertically integrated zonal momentum equations indicates that on short time scales the zonal pressure gradient is not balanced by the surface wind stress despite an apparent balance of these terms on longer (seasonal) time scales. The vertical redistribution of zonal momentum is complex. The strength of the wind determines both the magnitude and, likely, the mechanisms of momentum transport between the surface and the core of the undercurrent. During low wind conditions in April 1987 the turbulent stress divergence was significantly different in magnitude and vertical structure from that found during strong winds in November 1984. In November 1984 the turbulent stress divergence was much too large above 40 m to balance the residual term in the zonal momentum budget of Bryden and Brady (1985, 1989) and decayed exponentially with depth from the wind stress value at the surface. In April 1987 the turbulent stress divergence was smaller than that required by Bryden and Brady and decayed linearly from the surface wind stress. For a proper comparison with Bryden and Brady’s zonal momentum balance, it is necessary to determine the annual average turbulent stress divergence.
Genre Article
Identifier Hebert, D., J. Moum, C. Paulson, D. Caldwell, T. Chereskin, and M. McPhaden (1991), The Role of the Turbulent Stress Divergence in the Equatorial Pacific Zonal Momentum Balance, J. Geophys. Res., 96(C4), 7127-7136, doi:10.1029/91JC00271.

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