High-resolution vertical profiling of aerosols microphysical and optical properties during the 2024 LEADER UAV...

This study aims to highlight the benefits of unmanned aerial vehicle (UAV) system in atmospheric aerosol research, particularly for obtaining information on the vertical variability of aerosol single-scattering properties in the lower troposphere. The results discussed in this paper were collected during the spring 2024 campaign at Nadarzyce Airport (Northwestern Poland). The UAV was equipped with miniaturized instruments (a low-cost SPS30 aerosol counter and an RS41 radiosonde) to measure aerosol single-scattering properties and atmospheric thermodynamic parameters. Vertical UAV profiles, lidar observations, and ground-based in-situ measurements were collected during a mineral dust event and under background conditions. Dust particles were detected between 1.5 and 3.0 km, where the effective radius and scattering Ångström exponent (SAE) remained almost constant, at approximately 0.4 µm and -0.2, respectively, based on the SPS30 sensor. The aerosol scattering coefficient (ASC) in the dust layer fluctuated between 40 and 100 Mm⁻¹ (at 525 nm), showing similar variability to the aerosol extinction coefficient (AEC) retrieved from lidar observations. The estimated scattering optical depth of the dust layer was 0.109 ± 0.018 (at 525 nm). In contrast, non-dust particles in the planetary boundary layer (PBL) exhibited a significantly lower effective radius (approximately 0.10 µm) and higher SAE (1.8-1.9). This methodology can detect aerosols during long-range transport and extend lidar signal measurements to the ground level.