Evaluation of the AWR-WRF model configuration at high resolution over the domain of Greece

This study is a first attempt to obtain high resolution simulations of present climate in Greece, by applying dynamical downscaling using the Advanced Weather Research and Forecasting numerical model (WRF-ARW). We performed two simulations and thus, the model was set up with two different horizontal resolutions for the European domain (D01), of 20 and 25 km, driven by ERA-INTERIM reanalysis data for a total period of one year. For each simulation, the European domain (D01) was dynamically downscaled to the domain of Greece (D02), with grid spacing of 5 km. The first objective concerned the selection of the appropriate horizontal resolution of the first domain (at European scale) and the second was to validate the performance of various physics parameterizations of the WRF-ARW at high resolution on temperature and precipitation predictions, in the domain of Greece. In total, seven different sets of physics parameterizations were applied to investigate the model predictions against available observational data, by utilizing appropriate statistical metrics. It was deduced that there were no significant differences in the results imposed by the grid resolution of 25 km or 20 km of the parent (European) domain. The biases remained systematically negative (underestimation) for maximum temperature and positive (overestimation) for the minimum temperature for all configurations of about 2-2.4 °C and 1-1.5 °C, respectively. Simulation results in precipitation were not particularly satisfactory for any of the physical schemes, indicating overall a strong overestimation in absolute values, but with similarities found in the precipitation patterns.