Variabilité pluviométrique et désertification dans la zone Soudano-Sahélienne du Cameroun

Clair René BANGA

Variabilité pluviométrique et désertification dans la zone Soudano-Sahélienne du Cameroun

Keywords : Variability, rainfall, desertification, Soudano-Sahelian zone


During these last decades, the weather tools and equipment made it possible to revolutionize our knowledge on the fluctuations of the world climate and the evolution of the vegetation in general, those of Cameroun and the far - North of Cameroun in particular. Thanks to the satellitale imagery and to the cartographic data processing by computer, the glance on the territory evolved much. These new technologies enable us to better observe the effects of fitting, various changes which have occurred or being able to occur in the space structures like a basin or block dedicated to the oil exploitation. The objective of this study is to show the impact of the pluviometric variability on the development of the vegetation in the Waza-Logone plain. For that purpose, the methodology of this work consisted in plotting and the precipitation temperature curves of certain weather stations of the Waza-Logone plain to appreciate the climatic fluctuations starting from the cumulative frequencies of precipitations and the temperatures. With an aim of appreciating the turning into a desert of the studied zone, the Landsat-8/LDCM images were used OLI/TIRS to determine the transformed index of vegetation adjusted for the ground, or MSAVI2 (Second Modified Soil-Adjusted Végétation Index). From this study, it comes out that: the Waza-Logone plain is in the tropical zone where precipitations are weak (including between 411, 47 mm with Makary and 817, 19 mm with Maroua). The dry season is spread out November to March in Maroua where it goes from December to February. The series time present two trends: a rather weak increase in Maroua (0, 07 of coefficient of progression) relatively weak in Ndjamena (0,029) and more important in Makary (3, 85); a relatively weak rainfall in Kousseri and Waza (-0, 25) and rather strong in Yagoua (-0, 95). In the Zina block, it is observed an almost river deprived zone from North towards the block center and part of the South towards the block center also. It should be noted that the flow of these rivers is very significant in rainy season causing the floods and weak in dry season. This is why the vegetation which develops is also transitory and very sensitive to the bush fires. It is what explains turning into a desert. In the Makary block, the Southern part is occupied by a scattered vegetation, stopped by naked grounds zones. The Lake Chad circumference is dominated by a low vegetation substituted by farms. One notice herbaceous savannas with shrubs in the withdrawal zones of the Lake Chad.


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