Assimilation of Geosat Altimetric Data in a Nonlinear Reduced-Gravity Model of the Indian Ocean. Part 1: Adjoint Approach and Model-Data Consistency
| Autor: | Eric Greiner, Claire Perigaud |
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| Rok vydání: | 1994 |
| Předmět: | |
| Zdroj: | Journal of Physical Oceanography. 24:1783-1804 |
| ISSN: | 1520-0485 0022-3670 |
| DOI: | 10.1175/1520-0485(1994)024<1783:aogadi>2.0.co;2 |
| Popis: | Geosat sea-level variations are assimilated into a nonlinear shallow-water model of the Indian Ocean. After spinup, the model forced by observed winds over 1985–1988 provides a first guess for initial conditions on November 1986 and a mean thermocline depth used as a reference surface for altimetric observations. Data are assimilated during one year and north of 20°S. The model-data misfit is minimized using the adjoint model with respect to the initial conditions and the reference surface. The assimilation algorithm converges fast and steadily. The monthly rms difference between model and data is reduced from 21 to 16 m. The optimal thermocline surface is significantly affected by assimilation. Large changes occur along the paths of the throughflow and South Equatorial Current. It is found that the optimal mean state is valid only for the period of assimilation. It degrades the agreement between observations and simulations for the following year because of the large interannual event that took ... |
| Databáze: | OpenAIRE |
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