Climate and extreme rainfall events in the Mono river basin (West Africa): investigating future changes with Regional Climate Models.

Ernest Amoussou (1, 2, 3, 4) , Hervé Awoye (5, 6) , Henri S. Totin Vodounon (1, 2) , Salomon Obahoundje (3) , Pierre Camberlin (4) , Arona Diedhiou (3, 7) , Kouakou Kouadio (3, 8, 9) , Gil Mahe (10) , Constant Houndenou (2) , Michel Boko (2)

1 Département de Géographie et Aménagement du Territoire
2 LACEEDE - Laboratoire Pierre Pagney, Climat, Eau, Ecosystème et Développement
3 African Centre of Excellence on Climate Change, Biodiversity and Sustainable Development
4 BGS - Biogéosciences [UMR 6282]
5 LHME - Laboratoire d’Hydraulique et de Maîtrise de l’Eau
6 Department of Geography [Calgary]
7 IGE - Institut des Géosciences de l’Environnement
8 LPA-MF - Laboratoire de Physique de l'Atmosphère et de Mécanique des Fluides
9 Station d'écologie de Lamto
10 HSM - Hydrosciences Montpellier

This study characterizes the future changes in extreme rainfall and air temperature in the Mono river basin where the main economic activity is weather dependent and local populations are highly vulnerable to natural hazards, including flood inundations. Daily precipitation and temperature from observational datasets and Regional Climate Models (RCMs) output from REMO, RegCM, HadRM3, and RCA were used to analyze climatic variations in space and time, and fit a GEV model to investigate the extreme rainfalls and their return periods. The results indicate that the realism of the simulated climate in this domain is mainly controlled by the choice of the RCMs. These RCMs projected a 1 to 1.5 °C temperature increase by 2050 while the projected trends for cumulated precipitation are null or very moderate and diverge among models. Contrasting results were obtained for the intense rainfall events, with RegCM and HadRM3 pointing to a significant increase in the intensity of extreme rainfall events. The GEV model is well suited for the prediction of heavy rainfall events although there are uncertainties beyond the 90th percentile. The annual maxima of daily precipitation will also increase by 2050 and could be of benefit to the ecosystem services and socioeconomic activities in the Mono river basin but could also be a threat.

Mots clés: Mono basin; extreme rainfall events; ENSEMBLE; regional climate models

Domaines: Climatologie; Hydrologie

Ernest Amoussou, Hervé Awoye, Henri S. Totin Vodounon, Salomon Obahoundje, Pierre Camberlin, et al.. Climate and extreme rainfall events in the Mono river basin (West Africa): investigating future changes with Regional Climate Models.. Water, 2020, 12 (3), pp.833. ⟨10.3390/w12030833⟩. ⟨hal-02733201⟩