A new radiosonde system for measuring the vertical variability of aerosol single scattering properties

Abstract. This study presents a newly developed balloon-borne AeroSonde system equipped with calibrated low-cost optical particulate matter sensors (SPS30) for vertically resolved aerosol optical measurements. Calibration of the sensors against reference instruments (Aurora 4000 nephelometer and LAS 3340) enabled the estimation of scattering coefficients (ASC), scattering Ångström exponent (SAE), and effective particle radius (R_eff), with Pearson correlation coefficients exceeding 0.88. The best agreement was obtained for ASC, while SAE and R_eff showed substantially larger uncertainties, limiting their use to qualitative discrimination between fine- and coarse-mode particles.

The AeroSondes were deployed for the first time during measurement campaigns in June and August 2025 over southeastern Poland. Soundings with vertical resolution below 10 m reached altitudes of 10–27 km a.g.l. during episodes of long-range transport, including North American biomass-burning plumes and Saharan dust intrusions. The vertical distribution of aerosol layers observed by the AeroSonde is consistent with active remote sensing measurements, showing good agreement in both the optical layering structure and the absolute values of extensive aerosol properties, with correlation coefficients ranging from 0.74 to 0.81. The extended vertical sounding range allows the estimation of column-integrated quantities, such as aerosol optical depth, as well as their contributions from individual layers, for example, within the planetary boundary layer.

These results demonstrate that low-cost, balloon-borne AeroSonde sensors can provide reliable vertical profiles of aerosol properties, supporting enhanced spatio-temporal coverage and improved evaluation of atmospheric aerosol models.