Sensitivity Study of the SPEM Model to the Assimilation of Synop Datasets Using Two Assimilation Schemes: (1) Nudging (2) The Kalman Filter/ Smoother
Final rept. 1 May-31 Dec 1993
MASSACHUSETTS INST OF TECH CAMBRIDGE
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From CTD surveys taken two months apart during the 1981 Ocean Tomography experiment southwest of Bermuda, a time-dependent ocean state is estimated that evolves from the first survey to the second survey. Mesoscale motions in this region are modelled by quasi-geostrophic dynamics. The model domain is a doubly periodic 600km x 600km square centered at 26 deg N, 70 deg W. The oceanic density field is expanded in terms of a horizontal Fourier series with vertical modes. Freely propagating Rossby waves in the first and second baroclinic modes are fit to the data in a least-squares sense at the two survey times. Linear dynamics are first used to evolve the ocean state to fit both surveys. Weakly nonlinear interactions between the waves are then allowed and are found to do a better job. The wave-wave interactions enable Rossby waves in the barotropic mode to enter into the baroclinic Rossby wave evolution as unknown control variables which can then be estimated.
- Physical and Dynamic Oceanography