Abhatoo - Centre Nationale de Documentation

The long term activity of the upwelling along the Moroccan Atlantic coast between Cape Blanc (21°N) and Cape Spartel (36°N) is investigated in this work using a monthly Ekman Upwelling Index over the period 1967-2019 (53 years). Three stations that are representative of the upwelling’s activity along the Moroccan Atlantic coast from North to South were selected in this study for analysis: ST5 (31°N-10.5°W) between Cape Sim and Cape Ghir, ST7 (29°N-10.5° W) between Cape Ghir and Cape Draa and ST12 (24.5°N-15.5°W) North Dakhla between Cape Boujdor and Cape Barbas. The results show a seasonal variability in the northern area between Cape Juby – Cape Spartel and a permanent activity mostly all the year in the southern area between Cape Juby - Cape Blanc. Strongest activities of upwelling were observed during summer seasons in the northern area, in particular over the period 1998-2003, and its activity slightly exceeded the average over the periods 1972-1977, 1980-1984, 2004-2008. The weakest upwelling activities in this region were observed in the fall-winter seasons, particularly during the periods 1967-1970, 1995-1998 and 2000-2005. In the southern area, the upwelling variations showed strong upwelling activity in summer over the periods 1967-1980 and 2009-2019, with annual and interannual variability between these two periods. This activity was slightly above average in summer over the 1981-2007 period, except for the years 1982-1983, 1988-1989, 1995-1997 and 2004-2007 where a relative downward trend was observed. Lower upwelling activities were observed in this area over the 2003-2010 period in fall /winter seasons.