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Our barotropic tidal estimates are obtained from forward and generalized-inverse solutions of the shallow water equations, in 2 nested multi-scale domains over high resolution bathymetry. Currently, we utilize 1-minute resolution Smith and Sandwell (2007) bathymetry.
Two nested domains are utilized:
The tidal forcing for MSEAS in the Philex domains is estimated using the described inverse barotropic shallow water spectral model (see the link below for a more complete description). For regional-scale basins the tidal forcing occurs pre-dominantly through the open boundary conditions and the contribution of the astronomical tidal forcing inside the domain is negligible. In such basins, the barotropic response of the ocean to the tidal signal in the open boundary conditions (OBCs) has to be accurately modeled.
Topex-Poseidon (TP) satellite altimeter data, with tracks shown in Figure 1, and the velocity and the SSH data from two moorings in the Panay (A1) and the Dipolog (A2) straits were assimilated in the inverse solution. The A1 and A2 moorings were deployed and operated by the team led by Janet Sprintall of the Scripps Institution of Oceanography as part of the Philex observational program. In addition to the Acoustic Doppler Current Profilers (ADCPs), the moorings were carrying pressure gauges, suitable for inferring the SSH. The Topex-Poseidon data, collected from the launch of the satellite in 1992, were provided to us in the form of tidal constituents (SSH amplitudes and phases) by Dr. Richard Ray, of the Planetary Geodynamics Laboratory at the NASA Goddard Space Flight Center.
The observational data were utilized to correct for errors in open boundary conditions of the nested domains. Strong dynamical constraints were utilized: the inverse tidal fields satisfy the shallow water equations exactly. Tidal constituent estimates (h,u,v) are then utilized as the boundary tidal forcing for MSEAS.
Tidal inversion was performed in the spectral domain for all main tidal constituents in the Philex region. The resulting tidal field estimates are plotted at three hour intervals for the Archipelago domain and nested domain.
Provided here are the barotropic estimates. Data files with barotropic tidal transports, velocities, and sea surface height at 1 min resolution can also be provided upon request. The in situ velocity measurements should be depth averaged before comparing against these model fields. We look forward to any feedback with regard to how these estimates compare against observational velocity data in the domain.
For more complete information on the details of the methodology see: Inverse Barotropic Tidal Estimation For Regional Ocean Applications [PDF].
Philippines Straits DRI home page (Hawaii - password-protected)
