The relationship between water mass formation and the
surface buoyancy flux, with application to Phillips' Red
Sea model
Chris Garrett,
Kevin Speer and Elina Tragou
J. Phys. Oceanogr., 25, 1696-1705, 1995.
A buoyancy flux across the sea surface between the outcropping of
isopycnals must be balanced by a subsurface diapycnal buoyancy flux.
If this flux were only advective, its derivative with respect to
buoyancy would provide a direct estimate of the buildup of volume between
isopycnals or rate of water mass formation. A diapycnal velocity,
however, requires diapycnal mixing which also causes a diapycnal
buoyancy flux, and it is shown that there is no reason to expect a
simple relationship between the advective and diffusive fluxes. For
a surface layer with vigorous vertical mixing and weak horizontal mixing,
however, the diapycnal diffusive flux of buoyancy is small, and the flow
through the base of the mixed layer can be derived from the derivative of
of the surface buoyancy flux with respect to buoyancy. These points are
illustrated by examination of the Phillips similarity solution for the
convective circulation driven in a channel by a uniform surface buoyancy
loss.
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