Aplicaciones de la altimetría espacial al estudio de la dinámica oceánica del golfo de Cádiz
Sea-level records, and their global and local spatio-temporal variations, are related to many oceanographic and geophysical features. The sea surface can also be visualised as the physical representation of the geoid, averaging the sea-surface records over long periods to eliminate the short periods...
| Autores: | , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2001 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/319132 |
| Acceso en línea: | http://hdl.handle.net/10261/319132 |
| Access Level: | acceso abierto |
| Palabra clave: | Altimetría por satélites Medio Marino Geodesia espacial dinámica oceánica |
| Sumario: | Sea-level records, and their global and local spatio-temporal variations, are related to many oceanographic and geophysical features. The sea surface can also be visualised as the physical representation of the geoid, averaging the sea-surface records over long periods to eliminate the short periods of dynamic perturbation. Over the last ten years, orbit determination improvements have opened up the possibility of using, for ocean dynamic and sea-level variation studies, several altimetric satellites, accurate to the sub-decimetre level (ERS-1, ERS-2, Topex-Poseidon). Of these satellites, Topex-Poseidon makes it possible to measure the sea-level variation over global or regional zones with an accuracy better than 5 cm. This paper presents the results of the sea-surface height measurements from Topex-Poseidon, corrected for wet and dry troposphere range delays, ionosphere delay, sea-state bias, the inverse barometer, loading effects and the oceanic, solid-earth and pole tides. The authors analyse the spatio-temporal stability of the geoid OSU91-a and the mean sea-surface OSUMSS95, comparing the behaviour of the dynamic signal using the two different surfaces along Topex profile 122, which overflies the Atlantic apertures of the Gulf of Cadiz. Long-term analysis has been done over several points located on the Iberian Atlantic continental margin using Topex Poseidon altimeter data collected from October 1992 (cycle 2) to October 1997 (cycle 186). The main findings of the data analysis present a semi-annual variation with peaks in autumn and winter, separated on the order of 20 cm, which could be explained by the seawater temperature seasonal variation and the doubtful use of the inverse barometer model to correct the response of the ocean to changes in atmospheric pressure. Records also show a secular variation in the regional sea level of roughly 3 mm/year, according to historical tide-gauge trends, which could also probably be explained by polar ice melting and a slight warming tendency of the ocean. |
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