Dust Radiative Effects and Impact on Energy Production over the Mediterranean Basin

Abstract. Atmospheric aerosols are among the key factors affecting the Earth’s radiation budget, playing a fundamental role in understanding climate forcing, feedback mechanisms, and their impact on future climate projections and on solar energy systems. More specifically, dust aerosol particles, which are characterized by high complexity of their optical and microphysical properties, remain one of the most uncertain components. In this study, we focus on four severe dust events across multiple sites in the broader Mediterranean Basin between 2021 and 2022. We employ a combination of ground-based 
remote sensing observations along with Radiative Transfer (RT) modelling, with the libRadtran package and METAL-WRF scheme, as well as photovoltaic (PV) power generation simulations using the Global Solar Energy Estimator (GSEE) to investigate the impact of the different optical and geometrical aspects of these events on solar radiation and solar energy. The results revealed that the strongest dust-induced attenuation was systematically observed in the direct component of solar radiation (DNI), with maximum losses frequently exceeding 60–80%, while Global Horizontal Irradiance (GHI) typically ranged between 5% and 25%. These findings were reflected directly into substantial PV power output losses, for both fixed tilt and two-axis tracking systems, reaching ~45% and 80%, respectively, with the impact on the latter being significantly higher due to their strong dependence on DNI. A sensitivity analysis based on how aerosol optical properties and solar geometry jointly influence PV energy production revealed that Solar Zenith Angle (SZA) plays the most dominant role, followed by Aerosol Optical Depth (AOD), which leads to strong attenuation independently of SZA under altered aerosol load conditions. Finally, the comparison of the modelled PV output estimated from the modelled irradiances based on the two different RT models with the PV output considering ground-based GHI measurements revealed a similar agreement under clear sky conditions, while under cloudy conditions, the analysis revealed the critical role of the diffuse horizontal irradiance (DHI) component in the simulations.