Analyse of past and projected changes in extreme precipitation indices in some watersheds in côte d'Ivoire

The purpose of this study is to analyse trends in annual rainfall extremes over five watersheds within Cote d'Ivoire using observed data (1976-2017) and projected (2020-2050) rainfall data from the fourth version of the Rossby Centre regional atmospheric model, RCA4, for the representative concentration pathways RCP 4.5 and RCP 8.5. Four rainfall extreme indices, namely, the consecutive dry days (CDD), maximum annual rainfall (Pmaxan), very wet day (R95p), and maximum 5-day rainfall (Rx5days), were considered for trend analysis by using the non-parametric modified Mann-Kendall test and the distribution mapping bias-correction technique to adjust the simulated regional climate model climate of the simulated daily precipitation. As a result, it is found that during the period 1976-2017, there was a significant downward trend in the drought-related index (CDD) at the Bagoue, Baya, Agneby, and Lobo watersheds. The Baya and N'zo watersheds also experienced a significant downward trend under the RCP 4.5 and RCP 8.5 scenarios. The flood-related indices (Pmaxan, R95p, and Rx5days) show a clear downward trend in the recorded data for almost all the considered watersheds and generally a significant upward trend for both cases. These findings indicate that the watersheds are vulnerable to climate-induced disasters.HIGHLIGHTS center dot This article is an original work.center dot This article analyse the past and projected changes in extreme precipitation indices.center dot This article allows to see the past and projected changes in extreme precipitation indices under different climate zone in Cote d'Ivoire.center dot This article allows to see a great change in extreme precipitation indices under different climate zone in Cote d'Ivoire in the near future.