Evaluation of a nonlinear reef parametrisation for steady flows

Abstract

Modelling ocean circulation in regions of high topographic complexity, notably around groups of reefs and islands, makes large demands on spatial resolution. This problem has largely been overcome by a parametrisation scheme in which the dynamics associated with flow around unresolved reefs and islands are represented by modified momentum equations on a relatively coarse grid. However, the performance of this scheme deteriorates at high velocities, due to the increasing importance of flow separation and eddy formation, processes that are excluded in the original scheme. We extend the earlier model to include a parametrisation of the nonlinear advective terms, and test the performance of the modified scheme in the case of steady flow.