6.8 Rigid lid surface pressure method

The rigid lid surface pressure method in MOM was developed by Smith, Dukowicz, and Malone (1992) and Dukowicz, Smith, and Malone (1993). A useful discussion of the analytical issues related to the surface pressure formulation can be found in the paper by Pinardi, Rosati, and Pacanowski (1995). The basic advantages over the streamfunction approach are the following:

1.

The elliptical operator has an H factor, rather than the H^-1 found in the streamfunction approach. This property makes the elliptical operator more readily inverted than with the streamfunction approach (see Section 6.4.3). In particular, steep topography is much less of an issue with the surface pressure approach.

2.

The boundary conditions for the elliptical problem are Neumann rather than Dirichlet. As discussed by Smith, Dukowicz, and Malone (1992) and Dukowicz, Smith, and Malone (1993), Neumann boundary conditions are much easier to handle on parallel machines than Dirichlet conditions.

As the formulation of the rigid lid surface pressure method follows quite closely the logic of the streamfunction approach, the details are not reproduced here. Rather, reference should be made to the Smith, Dukowicz, and Malone (1992), Dukowicz, Smith, and Malone (1993) and Pinardi, Rosati, and Pacanowski (1995) papers.