On tidal rectification, friction, and geostrophic degeneracy

Abstract

The indeterminacy of a frictionless, tidally rectified flow is a fundamental feature of the dynamics involved and cannot, indeed must not, be removed by the expedient of a coordinate transformation. This indeterminacy can only be removed by either specifying the flow in some manner at some time, or by the inclusion of friction. Tidal rectification for the general case of nonzero friction has been investigated in several studies in both the Eulerian and Lagrangian views, and leads to consistent schemes whereby the residual velocity field may be determined. -Author