Journal of Geophysical Research, 1999,
104 (C9), p. 21,217-21,226 ISSN 0148-0227
Deep velocity profiles taken in the equatorial Atlantic Ocean show equatorially trapped deep jets with similar features to those of the Indian and Pacific Oceans : a zonal velocity of the order of 10 to 20 cm/s and a meridional scale of 1°. In the Pacific and Indian Oceans, the zonal extent of the jets is at least 15° of longitude. Owing to the lack of synoptic measurements, we have no information on the zonal scale in the Atlantic Ocean, but we present here zonal velocity profiles, made at a 16-month interval, that have identical baroclinic structure in the western (35°W) and central basin (13°W). The Atlantic jets have a vertical scale larger (400-600 m) than those observed in the Pacific Ocean (250-400 m). Our measurements confirm the opposite directions of the jets for different seasons in the Atlantic Ocean. Furthermore, for a given season, the vertical profiles of zonal velocity at 35°W-0° are astonishingly similar at a 5-year interval. As in the Pacific and Indian Oceans, the jets are embedded in a large-vertical-scale current that changes direction with time. The few profiles available in the equatorial Atlantic Ocean suggest a seasonal reversal of the jets, but neither this nor the temporal variability of the large-scale current has been adequately resolved. (Résumé d'auteur)
