The study focusses mainly on the investigation of the model's
sensitivity to the parameterization of shortwave (SW) irradiance. To
this end, numerical experiments were conducted for four monthly
periods in year 2013. The impact of geographical and seasonal
variations as well as of sky conditions on the performance of the
model is examined and discussed. In addition, a simple approach is
followed for investigating the impact of variations in aerosol optical
depth on the model-derived GHI.