Monitoring the eastern Alboràn Sea using combined altimetry and in situ data

As part of the Observations and Modelling of Eddy–scale Geostrophic and Ageostrophic circulation project, a cruise to the Almeria–Oran front in the Eastern Alboràn (Western Mediterranean) was carried out from November 1996 to January 1997. During the cruise, a fine–scale survey, designed to be oriented along European Remote–sensing Satellite ground tracks, was repeated several times. Hydrographic and current profile data were collected continuously using an undulating, towed conductivity–temperature–depth sensor and an acoustic Doppler current profiler. The in situ data have been processed to give profiles of the absolute surface current at several locations across the front. Estimates of the absolute current profile have been made from repeated tracks in order to understand some of the sources of error. These ‘one–time’ calculations of absolute profiles have been merged with several years worth of altimeter data to monitor the flow across the Almeria–Oran front. At times the front appears to move to the south, apparently when the eastern Alboràn gyre collapses, as has been observed in previous studies.