Abstract:

 A scheme for estimating global and net solar radiation under clear-sky condition is developed based on an accurate radiation transfer model. Unlike previously used methods, this scheme utilises an idea of radiative band model in the calculations of solar radiation at the earth surface and includes as many atmospheric absorbing and scattering species as possible, which makes the scheme more accurate and globally applicable. The parameterization of aerosol scattering and transmittance proposed by Kokhanovsky et al. is adopted to consider the effects of aerosols on the surface solar radiation. All variables used in the calculations are available in any numerical weather prediction models or they can be obtained from satellite measurements. Therefore, the scheme can be used in a numerical weather prediction model as well as a land-surface model for estimation of solar radiation distribution. The scheme has been tested using the US Atmospheric Radiation Measurements dataset and aerosol data retrieved by the European Space Agency satellites. The results indicate that the scheme is very accurate, the mean relative error is less than 6%, and the root mean square error is 0.3 W •m^-2.

Key words:  Global radiation, Radiative transfer, Transmission, Radiative parameterization