Semi-empirical models for the estimation of global solar irradiance measurements in Morocco

Abstract

This paper presents semi-empirical models for estimating Global Horizontal Irradiance (GHI) under specific sky conditions. We analysed the models to estimate global horizontal irradiance measurements in four Moroccan regions. The data consists of a one-year period at four solar irradiance monitoring stations located in the south and south-east of the country, Missour, Erfoud, Zagora and Tantan. Several empirical clear sky models are considered for a Moroccan case study. These models are validated using (GHI) measurements from different stations over different time periods. The disagreement between the various measurements of GHI and the semi-empirical models used for the estimation of radiation in atmospheric physics and radiative transfer modeling is sometimes significant, especially in the presence of clouds or large concentration of aerosols. A good agreement is noticed between the measured values and those estimated by some models.