Assessment of High-Resolution Regional Climate Models for West Africa Within the Framework of CORDEX
- Post by: SOAPHYS-KZ
- 8 septembre 2025
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Section de la parution: Informations de publication
J. P. Soaphys, Vol 5, N°1 (2025) C25A07
Pages : C23A07-1 à C25A07-7
Informations sur les auteurs et affiliations
Moussa Ibrahim MAIGA1,2, Souleymane SANOGO2, Elijah Adesanya ADEFISAN3, Imoleayo GBODE 3
1West African Science Service Centre on Climate Change and Adapted Land Use (WASCAL), Graduate Research Program on West African Climate System (GRP-WACS)
2Laboratory of Optics of Spectroscopy and Atmospheric Sciences (LOSSA), Faculty of Sciences and Techniques of Bamako (F.S.T.)
3Federal University of Technology of Akure (FUTA)Corresponding author e-mail :*
ABSTRACT
This study evaluated nine regional climate models (RCMs) within the Coordinated Regional Climate Downscaling Experiment-Africa (CORDEX-Africa) to assess their performance in simulating climate patterns over West Africa (WA) from 1970 to 2005. Key climate variables, including precipitation, air temperature, and evaporation, were analyzed using statistical parameters such as correlation coefficient, mean bias (Mbias) compared to ERA5, and root mean square error (RMSE) compared to ERA5 data. The resolution of CORDEX RCMs is standardized to 0.25° × 0.25° grids. Results indicate R2 values of 91% for the Sahel, 95% for the savannah, and 88% for the Guinea Coast for precipitation. Negative Mbias values reveal an underestimation of monthly precipitation by the RCMs compared to ERA5. RMSE values range from 84 to 151.53 for the coastal zone, 38.54 to 78.03 for the savannah, and 27.34 to 42.15 for the Sahel. Evaporation R2 values are 93% for the Sahel, 93% for the savannah, and 86% for the Guinea Coast, with negative Mbias values except for CCLM5 simulations. RMSE varies from 23.09 to 61.41 for the coastal zone, 9.54 to 58.94 for the savannah, and 14.81 to 35.45 for the Sahel. Air temperature R2 values are 86% for the Sahel, 93% for the savannah, and 93% for the Guinea Coast, with positive Mbias indicating that RCMs overestimate monthly air temperature. RMSE values range from 81.04 to 84.96 across West Africa. Overall, CORDEX RCMs show an underestimation of precipitation, varied estimates of evaporation, and an overestimation of temperature, while maintaining strong correlation coefficients for all variables.
Keywords : CORDEX-Africa, West Africa, Regional Climate Models, Precipitation, Air temperature, Evaporation
RESUME
L’étude a évalué neuf modèles climatiques régionaux (RCM) de CORDEX-Afrique pour simuler les conditions climatiques en Afrique de l’Ouest de 1970 à 2005. Les variables clés telles que les précipitations, la température de l’air et l’évaporation ont été analysées à l’aide de paramètres statistiques comme le coefficient de corrélation, le biais moyen (Mbias) et l’erreur quadratique moyenne (RMSE) en comparaison avec les données ERA5. Les RCMs CORDEX, avec une résolution normalisée à des grilles de 0,25° × 0,25°, montrent des valeurs R2 élevées pour les précipitations (91% au Sahel, 95% dans la savane, 88% en zone côtière). Les Mbias négatifs indiquent une sous-estimation des précipitations mensuelles. Pour l’évaporation, les R2 sont élevés avec des Mbias négatifs, sauf pour les simulations CCLM5. Concernant la température de l’air, les RCMs présentent une surestimation, avec des Mbias positifs dans toute l’Afrique de l’Ouest. En résumé, les RCMs de CORDEX montrent une sous-estimation des précipitations, des estimations variées de l’évaporation et une surestimation de la température, tout en maintenant des coefficients de corrélation élevés pour toutes les variables.
Mots-Clés : CORDEX-Afrique, Afrique de l’Ouest, Modèles climatiques régionaux, Précipitations, Température de l’air, Évaporation
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