Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/acp-2018-358
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
06 Apr 2018
Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Atmospheric Chemistry and Physics (ACP).
Extreme levels of Canadian wildfire smoke in the stratosphere over central Europe – Part 2: Lidar study of depolarization and lidar ratios at 355, 532, and 1064 nm and of microphysical properties
Moritz Haarig1, Albert Ansmann1, Holger Baars1, Cristofer Jimenez1, Igor Veselovskii2, Ronny Engelmann1, and Dietrich Althausen1 1Leibniz Institute for Tropospheric Research, Leipzig, Germany
2Physics Instrumentation Center of General Physics Institute, Moscow, Russia
Abstract. Extremely high particle extinction coefficients, an order of magnitude higher than after the Mt. Pinatubo eruption in 1991, were measured in the stratosphere over Leipzig, Germany, on 22 August 2017. In a series of two articles, we present our observations of this record-breaking smoke event. In part 1 (Ansmann et al., 2018), we provide an overview of the smoke situation. The particle extinction coefficients reached 500 Mm−1 at 532 nm in the lower stratosphere around 15 km height and the smoke-related aerosol optical thickness (AOT) was close to 1.0 around noon. In part 2, we present the optical and microphysical properties of the fire smoke observed in a tropospheric layer from 5–6.5 km height and in a stratospheric layer from 15–16 km height. Three Raman lidars were run at Leipzig after sunset on 22 August. As a highlight, triple-wavelength polarization/Raman lidar measurements of the particle depolarization ratio and extinction-to-backscatter ratio (lidar ratio) at all three important lidar wavelengths of 355, 532, and 1064 nm could be performed. Very different particle depolarization ratios were found in the troposphere and in the stratosphere. The obviously compact and spherical tropospheric smoke particles caused almost no depolarization of backscattered laser radiation at all three wavelength (< 3 %), whereas the particles in the stratosphere lead to high depolarization ratios of 22 % at 355 nm and 18 % at 532 nm and a comparably low value of 4 % at 1064 nm in the stratosphere. The observed strong wavelength dependence is probably attributed to the narrow size distribution (accumulation mode) of irregularly shaped soot particles and the absence of a smoke coarse mode. The layer mean particle lidar ratios, on the other hand, were 40–45 sr (355 nm), and 65–80 sr (532 nm), and 80–95 sr (1064 nm) in both, the tropospheric and stratospheric layers indicating similar scattering and absorption properties. The 532 nm single scattering albedo was 0.8 in the stratospheric layer. The smoke particles were rather small (effective radius of 0.17 μm) in the tropospheric layer and much larger (effective radius of 0.32 μm) in the very dry stratosphere.
Citation: Haarig, M., Ansmann, A., Baars, H., Jimenez, C., Veselovskii, I., Engelmann, R., and Althausen, D.: Extreme levels of Canadian wildfire smoke in the stratosphere over central Europe – Part 2: Lidar study of depolarization and lidar ratios at 355, 532, and 1064 nm and of microphysical properties, Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2018-358, in review, 2018.
Moritz Haarig et al.
Moritz Haarig et al.
Moritz Haarig et al.

Viewed

Total article views: 279 (including HTML, PDF, and XML)

HTML PDF XML Total BibTeX EndNote
208 66 5 279 3 4

Views and downloads (calculated since 06 Apr 2018)

Cumulative views and downloads (calculated since 06 Apr 2018)

Viewed (geographical distribution)

Total article views: 279 (including HTML, PDF, and XML)

Thereof 278 with geography defined and 1 with unknown origin.

Country # Views %
  • 1

Saved

Discussed

Latest update: 20 Apr 2018
Publications Copernicus
Download
Share