Internal tide acoustic tomography: reliability of the normal modes expansion as a possible basis for solving the inverse problem

摘要

Using hydrodynamic and thermodynamic equations appropriate for modellinginternal tides, one can predict the current and temperature distributions associatedwith the ocean's dynamic modes. Comparing such predictions with observations from theINTIMATE'96 experiment, we nd a high degree of correlation between the rst 3 theoretically calculated dynamic modes and corresponding empirical orthogonal functions (EOF's) derived from an ensemble of temperature and current pro les. The implications are twofold.First, this implies that the dominant variability in the INTIMATE'96 experiment isindeed associated with internal tides. Secondly, it suggests that in future tidal experiments a theoretically generated basis may be used as e ectively as an EOF basis (which requires more extensive oceanographic measurements). We have also used the set of dynamic modes to simulate the e ect of the tides on acoustic propagation to understand the relative importance of the usual surface tide (barotropic) and the internal (baroclinic) tides.