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Factors of rainfall variability in Côte d’Ivoire and relationships with some environmental modifications Volume 16, issue 1, Mars 2005

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Authors
Laboratoire de géographie des milieux anthropisés (CNRS UMR 8141), Université des sciences et technologies de Lille (USTL), Avenue Paul Langevin, 59655 Villeneuve d’Ascq cedex, France, Institut de géographie tropicale, Département de géographie de l’université de Cocody, 22 BP 744, Abidjan 22, Côte d’Ivoire, Laboratoire d’étude des transferts en hydrologie et environnement (CNRS/IRD UMR 5564), Université Joseph Fourier, BP 53, 38041 Grenoble cedex 9, France, Antenne Institut de recherche pour le développement (IRD), 176, avenue Maradi, BP 11416, Niamey, Niger

Beyond the main negative trend observed during the period 1950-1996, the statistical analysis of Ivorian rainfall shows regional and seasonal significant differences in the intensity of rainfall anomalies. They seem to be linked to specific configurations of the tropical Atlantic Ocean thermal fields. Thus, the change of the seasonal interhemispheric thermal gradient recorded after 1973-1975 in the Atlantic Ocean has been partly correlated with the fall of rainfall observed for 30 years in Côte d’Ivoire. The thermal variations of the Equatorial and Southern Atlantic Ocean can also impose rainfall variations in Côte d’Ivoire, even if other forcings also seem to exist. These oceano-atmospheric interactions have a notable impact on the space-time variability of the vegetation fires in Côte d’Ivoire, by influencing the seasonal intensity of the fires on the one hand as well as their more or less early appearance during the dry season on the other hand. But any attempt at understanding the interactions between climate and vegetation must be based on a dynamic vision of the vegetation cover taking into account anthropogenic modifications, particularly in the forested areas of the western part of the country.