The following is our first attempt at such a model. The reader is cautioned that the results are quite preliminary. There are two approaches being used to derive tides from altimetric records. One employs pure data analysis and hence the results are not subjected to dynamical constraints. However, our approach is different in the sense that full nonlinear dynamical equations are used and the model is constrained by observations using a simple assimilation scheme that enables most of the computing power to be used for providing dynamical calculations at high resolution and not the mechanics of data assimilation.
High resolution enables a more accurate topography to be employed as well.
This should be kept in mind when examining the preliminary results from this global model. We intend to replace DBDB5 values in shallow water as and when more accurate topography becomes available and redo the calculations. Results are now available for 4 primary constituents M2, S2, K1 and O1. We have used the altimetric tides as derived by University of Texas group for assimilation. The coamplitude-cophase plots are shown for M2, S2, K1 and O1 from the global model along with the results from UT analyses.