Identification of smoke and sulfuric acid aerosol in SAGE III/ISS extinction spectra
<p>We developed a technique to classify the composition of enhanced aerosol layers as either smoke or sulfuric acid aerosol using extinction spectra from the Stratospheric Aerosol and Gas Experiment III instrument aboard the International Space Station (SAGE III/ISS). This method takes advant...
Main Authors: | , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2022-09-01
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Series: | Atmospheric Measurement Techniques |
Online Access: | https://amt.copernicus.org/articles/15/5235/2022/amt-15-5235-2022.pdf |
Summary: | <p>We developed a technique to classify the composition of enhanced aerosol
layers as either smoke or sulfuric acid aerosol using extinction spectra
from the Stratospheric Aerosol and Gas Experiment III instrument aboard the International Space
Station (SAGE III/ISS). This method takes advantage of the
different spectral properties of smoke and sulfuric acid aerosol, which is
manifest in distinctly different spectral slopes in the SAGE III/ISS data.
Herein we demonstrate the utility of this method and present an evaluation
of its performance using four case-study events of two moderate volcanic
eruptions (2018 Ambae eruption and 2019 Ulawun eruption, both of which released
<span class="inline-formula"><</span>0.5 Tg of SO<span class="inline-formula"><sub>2</sub></span>) and two large wildfire events (2017 Canadian
pyroCb and 2020 Australian pyroCb). We provide corroborative data from the
Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument to support these classifications. This method correctly
classified smoke and sulfuric acid plumes in the case-study events <span class="inline-formula">></span>81 %
and <span class="inline-formula">></span>99.5 % of the time, respectively. The application of this method to
a large volcanic event (i.e., the 2019 Raikoke eruption; <span class="inline-formula">≥1.5</span> Tg SO<span class="inline-formula"><sub>2</sub></span>) serves as an example of why this method is limited to
small and moderate volcanic events as it incorrectly classified Raikoke's larger
sulfuric acid particles as smoke. We evaluated the possibility of smoke
being present in the stratosphere before and after the Raikoke eruption.
While smoke was present during this time period it was insufficient to
account for the magnitude of smoke classifications we observed. Therefore,
while this method worked well for large-scale wildfire events and eruptions
that inject less SO<span class="inline-formula"><sub>2</sub></span>, the size of the aerosol created by the
Raikoke eruption was outside the applicable range of this method.</p> |
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ISSN: | 1867-1381 1867-8548 |