Retrieval of 3 wavelengths aerosol properties from combined measurements of two ACTRIS lidar systems in troposphere and stratosphere

Multi-wavelength lidar measurements are crucial for aerosol remote sensing as they can provide additional information for aerosol characterisation. For such measurements typically the fundamental of Nd:YAG lasers at 1064nm and the first and second harmonic at 532nm and 355nm are used. However, due to limitations in the dynamic range and quantum efficiency of detectors, signal detection for the near infrared is challenging. Accordingly, special focus lies on the contribution of our new ACTRIS CARS (Centre for Aerosol Remote Sensing) reference lidar module for 1064nm equipped with novel APD recorder setups providing high signal quality at 1064nm compared to what was possible so far. (Haimerl, 2025)  

For the EGU conference 2026 we will present intensive aerosol properties retrieved for 3 wavelengths from combined measurements in troposphere and up to lower stratosphere of the portable reference lidar system POLIS-9 of ACTRIS CARS at LMU and of the quality assured ACTRIS lidar system TONI.

The measurements were conducted in the context of an intercomparison campaign at the KIT IMK-IFU* institute in Garmisch-Partenkirchen between 01.10.2025 and 13.11.2025. The POLIS-9 reference lidar system is a combination of two portable lidar modules POLIS-6 and POLIS-1064. POLIS-6 has co- and cross-polar channels for 355nm and 532nm and vibrational Raman channels respectively. The POLIS-1064 upgrade offers 1064nm co- and cross-polar channels and a rotational Raman channel. TONI at KIT IMK-IFU is equipped with co- and cross-polar channels and vibrational Raman channels at 355nm and 532nm and a total elastic channel at 1064nm. For additional observational capabilities in the stratosphere also a lidar from KIT IMK-IFU located on nearby Zugspitze Mountain with one 532 total channel was utilized. (Haimerl, 2026) 

Aerosol products were retrieved for different aerosol cases, like smoke layers on several days during the campaign, a Saharan Dust layer on 13.11.2025 up to 4km and clean atmosphere condition on 07.11.2025. Moreover, we also try to characterise a persistent layer between 10km and 20km in the stratosphere, potentially attributed to volcanic aerosol. (Trickl, 2024)

A detailed discussion of retrieval results will then be presented at the conference. Also, we are aiming to take close overpasses of the EarthCare satellite during our campaign into account and use our retrieval results for validating the satellite data.

 

This project receives funding from European Union’s Horizon research and innovation programme under grant agreement No. 871115. ACTRIS-D is funded by German Federal Ministry for Education and Research (BMBF) under grant agreements 01LK2001A-K & 01LK2002A-G.

 

Haimerl, M. (2025) POLIS1064 – A polarization Raman lidar with state-of-the-art recorders for minimizing analogue signal distortions, Proc. European lidar conference Warsow 2025.

Haimerl, M. (2026) Retrieval of tropospheric and stratospheric aerosol properties at 3 wavelengths from combined measurements of two ACTRIS lidar systems, Proc. ACTRIS Science Conference Oslo, 2026.

Trickl, T. et. al (2024) Measurement report: Violent biomass burning and volcanic eruptions – a new period of elevated stratospheric aerosol over central Europe (2017 to 2023) in a long series of observations, Atmos. Chem. Phys., 24.

(*IMK-IFU: Institute of Meteorology and Climate Research, Atmospheric Environmental Research Department)