Long Term Upwelling Activity along the Moroccan Atlantic Coast

Karim HILMI, Ismail BESSA, Ahmed MAKAOUI, Rachid HOUSSA, Mohammed IDRISSI, Omar ETTAHIRI, Anass EL AOUNI

Abstract


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.


Keywords


Morocco; Atlantic Coast; Ekman Upwelling Index; Seasonal & Long Term Activity.

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References


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DOI: https://doi.org/10.34874/IMIST.PRSM/fsejournal-v11i1.29233



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