Asmelash T. Reda
This work assesses the performance of the Sweden’s Meteorological and Hydrological Institute-the Rossby Centre Regional Atmospheric Climate Model, SMHI-RCA, in reproducing precipitation variability over Ethiopia. The simulated datasets, which are generated in the frame work of Coordinate Regional climate Downscaling Experiment (CORDEX) project, are validated by Global Precipitation Climatology Project (GPCP). Comparison of means, correlation coefficients, value of chi-square, bias test and test of significance showed that there is a good agreement between SMHI-RCA and GPCP rainfall at each grid point. Rotated Principal Components (RPCs) and the associated spectra for both datasets showed that the improvement of rainfall simulations is remarkable over different parts of the country. Classification using Hierarchical Clustering Analysis (HCLA) reasonably agrees with the reduction of data using Principal Component Analysis (PCA). Small scaled condensed homogeneous groups are identified from SMHI-RCA and GPCP datasets; several of them being shared by both. Zones of rainfall maxima for each cluster are primarily associated with the migration of Inter Tropical Convergence Zone (ITCZ); even though, elevation differences induce rainfall peaks to have a phase shift at local scale.
