Seasonal variations of MERIS-derived chlorophyll-a concentration in the coastal waters of Côte d'Ivoire in relation to sea surface temperature and hydrography

Remote sensing data from MERIS are used to study the seasonal variations of the chlorophyll-a concentration (Chla) in the coastal region of the Côte d’Ivoire. A ten-year monthly climatology of Chla is described for the Ivorian coastal and offshore domain and analyzed with a similar climatology of sea surface temperature (SST) from the MODIS-Terra mission. The period of highest Chla values extends from June to October with a peak in August-September in association with the minimum values of SST occurring in the upwelling season. Spatially, the highest Chla values appear along the coast. Then the seasonal variations of Chla and SST in the coastal region are specifically analyzed at locations associated with hydrographic measurement stations at the mouth of four major Ivorian rivers. For the four rivers, the maximum of the flow is in September-October, slightly later than the SST minimum. This flow maximum is also close to the Chla peak for three of the rivers. Assuming a simple linear model, 64% to 81% of the variance in Chla can be explained by river flow and SST, with an importance of these two predictor variables varying between rivers. These results highlight the complexity of the Chla variations in these coastal regions and the usefulness of remote sensing techniques for understanding the local ecosystems.

KOUADIO Maffoué Jeanne;  MELIN Frederic;  DJAGOUA E.V.;  AFFIAN K.;  HOEPFFNER Nicolas;  KASSI J.B.; 

2014-01-27

Research Publication IJSER

JRC83562

2229-5518,