Characterization of the rainy seasons in context of climate change : Case of Sassandra watershed (Côte d’Ivoire)

Résumé

The impacts of climate change are a reality nowadays and deserve to be studied at various scales in order to adapt better. It is in this context that this study has been treated and aims to characterize the rainy season in a context of climatic changes.

Using daily rainfall data and the agronomic method of Sivakumar, the start and end dates and also the durations of the rainy seasons have been determined. This method makes it possible to highlight the temporal and sptial variability of these climatic parameters of the rainy seasons in the Sassandra watershed in a context of climate change.

The results showed a late start and an early cessation of the rainy season after 1970. Indeed, the year 1970, represents the reference date of rainfall shortages in West Africa and Côte d'Ivoire in particular.               This has resulted in a reduction of about 30 to 35 days in the duration of the rainy season over the entire catchment area.

Depending on climatic zones, the start and end dates of the rainy seasons have been determined. Indeed, the great rainy seasons start on average between 11 March and 15 May and end between 19 June and 11 November. Its duration is 62 to 101 days (equatorial climate), 188 days (Mountain climate) and 156 to 166 days (tropical transitional climate).