Research Article
Evaluation of the Performance of CORDEX-Africa Regional Climate Models in Simulating Rainfall and Temperature over the Lake Tana Sub-Basin, Ethiopia
Behabtu Gobeze Mengiste*
,
Yingesu Lemma Mengste,
Temesgen Admasu Yazachew,
Abebe Chalew Haile
Issue:
Volume 12, Issue 2, June 2026
Pages:
25-35
Received:
15 June 2026
Accepted:
6 July 2026
Published:
28 July 2026
DOI:
10.11648/j.ajbes.20261202.11
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Abstract: Climate change is increasingly altering hydrological and climatic systems across the globe, with particularly severe consequences in Sub-Saharan Africa, where vulnerability is high and adaptive capacity remains limited. Ethiopia, and especially the Upper Blue Nile (Abay) Basin, is highly sensitive to climate variability because livelihoods, water resources, and agricultural production depend heavily on rainfall and temperature conditions. In this context, understanding the ability of climate models to simulate local climatic conditions is essential for generating reliable future climate projections and informing adaptation strategies. This study therefore evaluated the performance of three CORDEX-Africa regional climate models (RCMs) CCCma-CanESM2, MOHC-HadGEM2-ES, and MPI-M-MPI-ESM-LR in simulating rainfall and temperature over the Lake Tana sub-basin, one of the most important hydrological regions in Ethiopia. Observed rainfall and temperature data from four meteorological stations Bahir Dar, Gondar, Debre Tabor, and Dangla were used as reference data for the baseline period 1976-2005. The performance of the selected RCMs was assessed using widely applied statistical indicators, including Percentage Bias (PBIAS), Root Mean Square Error (RMSE), correlation coefficient (R), and coefficient of determination (R2). These metrics enabled the comparison of model outputs with observed climatic records in terms of magnitude, variability, and overall agreement. The evaluation results showed that the MPI-M-MPI-ESM-LR model outperformed the other two models in reproducing rainfall, maximum temperature, and minimum temperature across the study area, indicating its relatively higher suitability for climate impact analysis in the Lake Tana sub-basin. Future climate projections under Representative Concentration Pathways (RCP4.5 and RCP8.5) revealed a clear warming trend across the basin toward the end of the twenty-first century. Maximum temperature is projected to increase by about 3.2-4.4°C under the high-emission scenario (RCP8.5), while minimum temperature may rise even more substantially, by 6.4-7.9°C. In contrast, rainfall projections showed no consistent increasing or decreasing trend, suggesting considerable uncertainty in future precipitation patterns. Overall, the study emphasizes the importance of carefully selecting reliable regional climate models and applying bias correction techniques before using projected climate data for hydrological impact assessments, climate risk management, and long-term adaptation planning in climate-sensitive basins such as Lake Tana.
Abstract: Climate change is increasingly altering hydrological and climatic systems across the globe, with particularly severe consequences in Sub-Saharan Africa, where vulnerability is high and adaptive capacity remains limited. Ethiopia, and especially the Upper Blue Nile (Abay) Basin, is highly sensitive to climate variability because livelihoods, water r...
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