Evaluation of clear-sky solar spectral irradiance using radiative transfer model

Abstract

The amount of solar radiation incident on the Earth surface is important from the point of view of the environment and

energy generation. The objective of this work is to estimate the clear sky spectral and solar irradiance components based

on the framework of the Simple Model of the Atmospheric Radiation Transfer of Sunshine (SMARTS) radiative transfer

model. This model is used to analyze clear sky spectral distribution of solar irradiance and its components at wavelength

ʎ = 500 nm for Lagos area and Jos, Plateau state at air-mass two (AM2) for selected days that meet the criteria for clear

sky. Meteorological parameters such as air temperature, relative humidity, precipitable water among others, serve as

inputs to the model which calculates the spectral content, the atmospheric transmission parameters along with global solar radiation, direct (or beam) solar radiation and diffuse solar radiation. The results of the radiation parameters show good agreement with ground based measurements with percentage normalized root-mean-square-error of less than 10% for both locations (Akoka and Jos). The results show that the spectral content and the solar irradiance can be estimated with a good level of accuracy for application in the analysis of solar converters