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Monthly maps of remotely sensed sea surface temperatures derived from NOAA/AVHRR thermal images are used to describe changes in 'Intense Benguela Upwelling' during 1982-1999. The coastal area under investigation lies between 9-34°S and 8-20°E and the total area of cold water between the coast and the course of the 13°C isotherm is considered to be an index of intense, active upwelling. It exhibits a decreasing trend over the study period of 18 years and some evidence for a quasi-cycle of about 27 months. Seasonal cycles are discussed for the total cold water area as well as for its mean alongshore and offshore extents. The main season of cold surface water was found to occur between July and September during the austral winter. It peaks in August with a mean area of about 30×10 3 km 2 and relaxes drastically during the rest of the year. The underlying process of intense coastal upwelling is regionally trapped in two coastal zones. These are centred around 26 and 29°S and reach a mean offshore extension of 210 and 130 km, respectively, to form giant upwelling filaments. The area of cold water drastically shrinks, roughly by a factor of two, during weak upwelling years but significantly expands by a factor of about 1.5 during strong years. Associated sea level changes along the southwest African coast were derived from measurements at four coastal stations between 23 and 34°S during 1982-1987. The first principal component describes about 63 % of the total sea level variance. The lowest sea levels were found in the prominent Lüderitz cell near 26°S. On both the annual and interannual time scale, decreasing cold water areas are accompanied by increasing sea levels and vice versa. Mean seasonal cycles reveal that variations in the total cold water area lag behind those in the sea level along the entire southwest African coast by about 1 month. © 2001 Ifremer/CNRS/IRD/Éditions scientifiques et médicales Elsevier SAS Résumé − Modifications saisonnières et interannuelles de l'upwelling intense de Benguela. Des cartes mensuelles de température de surface de la mer, obtenues par satellite à partir du capteur NOAA/AVHRR, sont utilisées pour décrire l'épisode intense de la remontée d'eau de Benguela entre 1982 et 1999. La région côtière étudiée s'étend de 9 à 34°S et de 8 à 20°E ; la totalité de la tâche d'eau froide entre la côte et l'isotherme 13°C est considérée comme le signe d'un upwelling intense. Cet indice décroît durant la période de 18 années et un cycle de 27 mois apparaît. Les cycles saisonniers sont discutés pour l'ensemble de la région « froide ». La saison principale de remontée se situe entre juillet et septembre, durant l'hiver austral. Elle atteint son maximum en août avec une aire moyenne concernée de 30×10 3 km 2 et l'upwelling est particulièrement faible tout le reste de l'année. Deux foyers de remontée existent le long de la côte. Ils sont centrés sur 26°et 29°S et s'étendent au large respectivement jusqu'à 210 et 130 km en formant des filaments géants. L'aire de remontée se réduit de moitié durant les...

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