Greiner E., Arnault Sabine. (2000). Comparing the results of a 4D-variational assimilation of satellite and in situ data with WOCE CITHER hydrographic measurements in the tropical Atlantic. Progress in Oceanography, 47 (1), p. 1-68. ISSN 0079-6611.
Titre du document
Comparing the results of a 4D-variational assimilation of satellite and in situ data with WOCE CITHER hydrographic measurements in the tropical Atlantic
Progress in Oceanography, 2000,
47 (1), p. 1-68 ISSN 0079-6611
TOPEX/POSEIDON and ERS1 sea level anomalies, expendable bathythermograph temperature profiles, sea surface salinities and satellite sea surface temperatures have been assimilated from November 1992 to October 1994 into a non-linear primitive equation model of the tropical Atlantic Ocean using a 4D-variational method. The model is forced monthly by ship winds and climatologies of heat and fresh water fluxes. The comparison between the model run both with and without assimilation is first analyzed in terms of empirical orthogonal functions, and along particular sections in the basin. The results are then compared with independent hydrological measurements obtained during the World Ocean Circulation Experiment cruise CITHER 1, in the tropical Atlantic Ocean in early 1993. The comparison is improved globally with assimilation. The largest impact or the assimilation appears in the North Equatorial Counter Current and the North Equatorial Current (5 degrees N-15 degrees N). Sub-surface thermocline motions were not reproduced by the model alone, but, are, clearly depicted in the assimilation results along 7 degrees 30'N and are in good agreement with the CITHER I data. Considerations about the assimilation technique, the model and the forcing data sets are also discussed via this independent validation.
