Implementation of a free surface extension to HOPS PE

Remove rigid-lid approximation and explicitly maintain surface pressure. Allow vertical levels to deform according to free surface, related to surface pressure via hydrostatic equation.

Compute surface pressure with Dukowicz & Smith algorithm

• implicit in time for greater stability
• split-time algorithm to enable use of efficient conjugate gradient solvers

Adapt for use in HOPS

• synoptic initialization
• open boundary conditions
  • including barotropic tidal forcing
• assimilation
• two-way nesting

Testing the free surface extension to HOPS PE

Use available validation data sets to demonstrate at least equivalent skill between rigid-lid HOPS PE & free surface HOPS PE

Stage tests in order of increasing importance of free surface effects.

1. MREA-03/BP-03 Results
2. AOSN-II Results

Adding tides

Force open boundaries with a first estimate of principal tidal constituents obtained via shallow water model in a 2-step process

1. Global TPXO5 (Egbert, Bennett et al.)
2. Nesting regional OTIS inversion using tidal-gauges and TPXO5 at open boundaries

For further details, see http://mseas.mit.edu/archive/leslie/AOSNII/TIDES/

References