Meteorological Radiation Model (MRM v6.1): Improvements in diffuse radiation estimates and a new approach for implementation of cloud products

摘要: Abstract This work reviews techniques and models for solar radiation simulations communicates further improvements performed in the Meteorological Radiation Model (MRM) developed at National Observatory of Athens. The new version (MRM v6.1) considers a forward to-the-ground scattering as function altitude diffuse estimates, while concurrently uses two running codes i.e., with sunshine duration input v6.1a) cloud products v6.1b). leads to increase radiation, especially low zenith angles, better measured (RMSE=36.3% MBE=6.5%, against RMSE=42.0% MBE=22.3% latest MRM v6). These changes lead also global (RMSE=8.7% RMSE=9.5% v6), direct is not affected. accuracy increases significantly clear-sky conditions, it shows small dependence on aerosol amount altitude. Furthermore, sub-version v6.1b calculations transmittance have been modified allow inclusion inputs case non-availability data. In this study, MERRA retrievals optical depth fraction transmittance; these parameters usually significant uncertainties hourly radiations, large fractions. indicates need high spatial temporal resolution satellite data cloudiness accurate estimations under cloudy conditions highlights incapability radiative transfer such simulations. However, monthly basis both v6.1a provide thus rendering v6.1 powerful tool energy applications.