Stratospheric aerosol measurements using a Frequency Scanning Lidar method

We present a Frequency Scanning Lidar method (FSL method) for measuring stratospheric aerosols up to an altitude of 30 km. This approach leverages an ultra-narrowband Alexandrite ring laser with a spectral width of 3.3 MHz and high-resolution spectroscopy with a spectral resolution of 100 MHz, enabling the separation of molecule and aerosol scattering. The FSL method's solar-blind Mie channel allows for measurements both day and night, while its compact design (approximately one cubic meter in volume) facilitates mobile deployment. With a vertical resolution of 200 m and a temporal resolution of 20 min, as achieved for the data presented here using the instrument configuration described in this study, the FSL method provides high-resolution observations of aerosol distributions in the stratosphere. The uncertainties of the FSL method for the backscatter coefficient are approximately 1.5 × 10−10 m−1 sr−1 at 20 km, both during day and night. We demonstrate the method's capabilities by presenting backscatter coefficient profiles measured during selected periods from 2022 to 2024. These profiles show good agreement with satellite-derived profiles from the Ozone Mapping and Profiler Suite Limb Profiler (OMPS-LP) and the Stratospheric Aerosol and Gas Experiment on the International Space Station (SAGE III/ISS) with a mean absolute deviation of ∼ 25 % at altitudes of 15–25 km. This demonstrates the potential of the FSL method for providing high-resolution, long-term observations of stratospheric aerosols.