Abstract
A model based on vertically integrated boundary layer equations is used to study the influence of friction on equatorial mixed Rossby-gravity waves of various scales. It is assumed that the boundary layer pressure is completely determined by an interior solution for mixed Rossby-gravity waves of vertical wavelengths in the range 9–12 km. Except for the longest zonal scales the low level convergence pattern is controlled primarily by friction and the convergence is a maximum near critical latitudes where the wave frequency equals plus or minus the Coriolis frequency. Nonlinear advection in the boundary layer weakens the positive divergence maxima for long waves, but leaves the convergence maxima concentrated near the critical latitudes. A simple interactive model is formulated in which the CISK process for mixed Rossby-gravity waves is parameterized by letting boundary layer convergence be a mass sink to the interior flow which is governed by the shallow water equations with an empirically derived 25 m equivalent depth.
© 1975 James R. Holton, published by Stockholm University Press
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