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

Abstract

This chapter presents semi-empirical models for estimating global horizontal irradiance (GHI) under specific sky conditions. We analysed the models to estimate GHI measurements in four regions of Morocco. The data consist of a 1-year period at four solar irradiance monitoring stations located in the south of the country, Missour (32.86°N, -4.11°E), Erfoud (31.49°N, -4.22°E), Zagora (30.27°N, -5.85°E) and Tantan (28.50°N, -11.32°E). 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 semiempirical models used for the estimation of radiation in atmospheric physics and radiative transfer modelling is sometimes significant, especially in the presence of clouds or large concentrations of aerosols. A good agreement is noticed between the measured values and those estimated by some models.