Bias-Correcting the Maximum and Minimum Air Temperatures of Egypt Using a High-Resolution Regional Climate Model (RegCM4)

Abstract

The regional climate model (RegCM4) was used to project the maximum and minimum air temperatures (Tmax and Tmin) of Egypt considering the worst-case scenario: Representative Concentration Pathway 8.5 (RCP8.5). To achieve this goal, the spatial pattern of the simulated Tmax and Tmin was first examined. After that, the simulated Tmax and Tmin were bias-corrected in the historical period with respect to station observations using the Linear-Scaling (LS) technique. Finally, the LS was used to correct the two future scenarios. To downscale the RegCM4, the medium resolution of the Earth System Model of the Max Planck Institute (MPI-ESM-MR) was used to provide the lateral boundary condition and sea surface temperature. The results showed that both Tmax and Tmin exhibit the highest increase in the far-future period (2081–2100) particularly over Western Egypt, the Red Sea, and Upper Egypt (by 4–6 °C). Additionally, the RegCM4 performance is remarkably improved when the LS method is used. Such performance is indicated by a low mean bias in the validation period compared to the evaluation period over majority of stations. Further, the added value of the LS is noted in Tmin more than Tmax. Therefore, the RegCM4 can be used to project the Tmax and Tmin using the LS over the location of interest. In addition, using multiple General Circulation Models (GCMs) is necessary to account for uncertainty associated with the atmospheric forcing.

Keywords

• Egypt
• future scenario
• linear-scaling
• regional climate model
• temperature