Effects of atmospheric aerosol on the direct normal irradiance on the earth's surface

• The idea of aerosol correction factor in solar hydrogen production system has been proposed.
• Three models have been used to calculate attenuation coefficient of DNI.
• The experimental DNI has been investigated in this paper.

Direct normal irradiance (DNI) plays a key role on the quantity and rate of hydrogen production. The accurate calculation of DNI has very important significance for low-cost hydrogen economy and efficient utilization of solar energy. This study mainly takes account of the influence of atmospheric aerosol on DNI and the experimental tests. The main idea of this paper is: obtaining the distribution characteristics of aerosol particles in the atmosphere and the optical depth of aerosol spectrum based on inversion method of ground observation station data; calculating the attenuation coefficient of solar spectrum with classical Mie scattering theory and particle system radiation characteristics; calculating aerosol attenuation coefficient under full spectrum, namely the aerosol correction factor (defined as the ratio of the attenuation coefficient of aerosol atmosphere to standard atmosphere under full spectrum) with Planck model, Rosseland model and Planck–Rosseland model respectively; choosing with the theoretical calculation model of aerosol correction factor based on the solar spectrum radiation calculated by SMARTS software; verifying the accuracy of this theoretical model with experimental DNI in city Harbin. The results show that there is a good agreement with a minimum variation of 3.08% and a maximum variation of 9.97%.