Extreme levels of Canadian wildfire smoke in the stratosphere over central Europe on 21–22 August 2017
<p>Light extinction coefficients of 500 Mm<sup>−1</sup>, about 20 times higher than after the Pinatubo volcanic eruptions in 1991, were observed by European Aerosol Research Lidar Network (EARLINET) lidars in the stratosphere over central Europe on 21–22 August 2017....
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-08-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/18/11831/2018/acp-18-11831-2018.pdf |
| Summary: | <p>Light extinction coefficients of 500 Mm<sup>−1</sup>, about 20 times higher than
after the Pinatubo volcanic eruptions in 1991, were observed by European
Aerosol Research Lidar Network (EARLINET) lidars in the stratosphere over
central Europe on 21–22 August 2017. Pronounced smoke layers with a 1–2 km
vertical extent were found 2–5 km above the local tropopause. Optically
dense layers of Canadian wildfire smoke reached central Europe 10 days after
their injection into the upper troposphere and lower stratosphere which was
caused by rather strong pyrocumulonimbus activity over western Canada. The
smoke-related aerosol optical thickness (AOT) identified by lidar was close
to 1.0 at 532 nm over Leipzig during the noon hours on 22 August 2017.
Smoke particles were found throughout the free troposphere (AOT
of 0.3) and in the pronounced 2 km thick stratospheric smoke layer at an
altitude of 14–16 km (AOT of 0.6). The lidar
observations indicated peak mass concentrations of
70–100 µg m<sup>−3</sup> in the stratosphere. In addition to the lidar
profiles, we analyzed Moderate Resolution Imaging Spectroradiometer (MODIS)
fire radiative power (FRP) over Canada, and the distribution of MODIS AOT and
Ozone Monitoring Instrument (OMI) aerosol index across the North Atlantic.
These instruments showed a similar pattern and a clear link between the
western Canadian fires and the aerosol load over Europe. In this paper, we
also present Aerosol Robotic Network (AERONET) sun photometer observations,
compare photometer and lidar-derived AOT, and discuss an obvious bias (the
smoke AOT is too low) in the photometer observations. Finally, we compare the
strength of this record-breaking smoke event (in terms of the particle
extinction coefficient and AOT) with major and moderate volcanic events
observed over the northern midlatitudes.</p> |
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| ISSN: | 1680-7316 1680-7324 |