Dust optical properties in the UV

Ultraviolet (UV) radiation has a major impact not only on human health (e.g., vitamin D synthesis, erythema, and skin and eye diseases) but also on the Earth’s environment, influencing all living organisms and interacting chemically with various commonly used materials. For these reasons, accurately measuring UV radiation and understanding its response to atmospheric changes—its primary modulator and the medium responsible for the largest variations in the UV flux reaching the surface—are of great importance. 

Aerosols, particularly mineral dust, exert significant effects on solar radiation by scattering or absorbing it, thereby contributing to atmospheric cooling or warming, respectively. Several optical properties govern these effects, including the Single Scattering Albedo (SSA), the refractive index, and the Absorption Aerosol Optical Depth (AAOD). Previous studies have shown that dust optical properties in the UV range, are linked to enhanced absorption, which is linked to the mineralogical composition of the particles. However, NASA’s Aerosol Robotic Network (AERONET), one of the main global sources of aerosol data, does not provide inversion products (such as SSA and the imaginary part of the refractive index, k) at UV wavelengths. Consequently, there remains limited knowledge regarding dust effects on UV radiation. This work therefore aims to deepen the understanding of the absorption properties of dust aerosols in the solar UV range. Knowing these properties especially in dust events that are commonly linked with moderate to high aerosol optical depth is essential for the determination of UV e.g. in UV Index forecasting models. 

To achieve this objective, a multi-instrumental approach will be employed using ground-based solar radiometers located at key stations influenced by major global dust sources (namely the Sahara, the Arabian Desert, and the arid regions of Western and Central Asia). 

Acknowledgements: This work is supported by the Marie Curie Doctoral Network project (GA101168425), Dust-DN and by the COST Action HARMONIA CA21119, supported by COST (European Cooperation in Science and Technology).