Observations of Mineral Dust Using Novel Remote Sensing and UAV Technologies

Mineral dust, significantly affects climate, human health, and the economy. The Mediterranean and the Eastern Atlantic are key for dust research: the Mediterranean lies at the crossroads of dust, continental pollution, and marine aerosols, while the Eastern Atlantic is directly influenced by the Saharan Air Layer transporting dust across the Atlantic. Despite their importance, observational coverage remains sparse, especially in the Eastern Mediterranean, and only a few studies combine multiple observational techniques and modeling for comprehensive dust characterization.
This PhD thesis addresses these gaps by integrating ground-based remote sensing and unmanned aerial vehicle (UAV) in-situ measurements at high-altitudes with atmospheric modelling to improve understanding of the vertical distribution, optical properties, and mineralogical composition of dust in the Mediterranean and Eastern Atlantic.
In this study ground-based observations with lidar and sun-photometer measurements are complemented by UAV-based instrumentation providing detailed vertical profiles of dust-laden atmospheres.
A key contribution of this work is the development of a simplified and reproducible lidar depolarization characterization technique using a well-calibrated reference system, allowing retrospective application to past datasets. In addition, the dust volume-to-extinction ratio (ζ) was evaluated under different dust conditions by combining UAV-derived particle size distributions with lidar extinction profiles. This represents one of the first airborne evaluations of ζ in these regions and reveals significant deviations from values derived from simulations and AERONET retrievals, particularly under coarse and giant particle conditions, highlighting the need to better represent large particles in remote sensing retrievals and models.
Finally, using various AERONET stations in the Mediterranean, satellite, UAV, and insitu observations with METAL-WRF simulations enabled the identification of distinct optical and mineralogical signatures of selected dust outbreaks in the region.
Overall, this work demonstrates the value of integrating remote sensing, UAV observations, and modeling to advance understanding of mineral dust and its impacts on the Earth system.