Evaluation of the performance of bias-corrected CORDEX regional climate models in reproducing Baro–Akobo basin climate

Abstract

The applicability of the regional climate model (RCMs) for catchment hydroclimate is obscured due to their systematic bias. As a result, bias correction has become an essential precondition for the study of climate change. This study aimed to evaluate the skill of seven rainfall and five maximum and minimum temperature RCM outputs against observed data in simulating the characteristics of climate at several locations over the Baro-Akobo basin in Ethiopia. The evaluation was performed based on raw and bias-corrected RCMs against observed for a long-term basis. Several statistical metrics were used to compare RCMs against observed using a pixel-to-point approach. In this finding, raw RCMs showed pronounced biases such as lower correlation and higher PBIAS in estimating rainfall and minimum temperature than maximum temperature. However, most RCMs after bias correction showed better performance in reproducing the magnitude and distribution of the mean monthly rainfall and temperature and improve all the statistical metrics. The Mann-Kendall trend test for observed and bias-corrected RCMs indicated a decreasing annual rainfall trend while the maximum and minimum temperature showed an increasing trend in most stations. In most statistical metrics, the ensemble mean resulted in better agreement with observation than individual models in most stations. In general, after bias correction, the ensemble adequately simulates the Baro-Akobo basin climate and can be used for evaluation of future climate projections in the region.

Quantifying Impacts of Future Climate on the Crop Water Requirement, Growth Period, and Drought on the Agricultural Watershed, in Ethiopia

“…The two climate change models applied for this study were derived from the Regional Climate Models (RCM) from the CORDEX Africa project. The regional climate model has a resolution of 0.48° and it is widely used in most African countries (Ashaley et al, 2020; Mengistu et al, 2021). This study compared several climate models with a reasonable spatial resolution to retrieve data for two climate variables (rainfall and temperature) at a monthly scale.…”

“…The General Circulation Models (GCM) have been widely used in climate change studies. Regional Climate Models (RCMs) have been used to dynamically downscale GCM output to scales more suitable to end regional applications (Mengistu et al, 2021; Shrestha et al, 2014). Compared to GCMs, RCMs provide better information and representation of different topographies at finer temporal and spatial scales (Giorgi et al, 2008).…”

“…The Coordinated Regional Climate Downscaling Experiment in Africa (CORDEX), which is produced under the Coupled Model Inter-Comparison Project Phase 5 (CMIP5), has provided many regional climate models and their scenarios in the Representative Concentration Pathways (RCP). The evaluation and application of CORDEX outputs were widely reported for the water resource impact assessment in Ethiopia (Alehu et al, 2022; Ashaley et al, 2020; Asnake et al, 2021; Mengistu et al, 2021; Tesfaye et al, 2020).…”

Assessing impacts of future climate on the crop water requirement and growth period. A case of Lake Hawassa watershed, Ethiopia

“…The climate change models applied for this study were derived from the Regional Climate Models (RCM) from the project of CORDEX Africa. The regional climate model has a resolution of 0.48 o and it is widely used in most African countries (Ashaley et al 2020;Mengistu et al 2021). This study compared several climate models with a reasonable spatial resolution to retrieve data for two climate variables (rainfall and temperature) at a monthly time scale.…”

“…models and their scenarios in the Representative Concentration Pathways (RCP). The evaluation and application of CORDEX outputs were widely reported for the water resource impact assessment in Ethiopia (Ashaley et al 2020;Tesfaye et al 2020;Alehu et al 2021;Asnake et al 2021;Mengistu et al 2021).…”