Application of a Direct Inverse Data Assimilation Method to the M2Tide on the Newfoundland and Southern Labrador Shelves

Abstract

Abstract The barotropic M2 tide over the Newfoundland and southern Labrador Shelves and adjacent deep ocean is studied using a linear harmonic finite-element model and a newly developed direct inverse method for data assimilation. The dataset includes harmonic tidal constituents from TOPEX/Poseidon altimetry, coastal tide gauges, bottom pressure gauges, and moored current meters. Three modeling approaches are taken: a conventional modeling approach with boundary conditions specified from along-boundary observations; a full interior data assimilative approach, which provides an optimal domain-wide solution; and a sensitivity study in which the roles of various data subsets and the frictional parameters are investigated. The optimal solution from the full assimilative approach has rms misfits of 3.5 cm and 1.3 cm s−1 for elevation and current, respectively (in terms of distances on the complex plane), compared to overall rms amplitudes of 30 cm and 6 cm s−1. These misfits are reduced by more than 40% and 70...