Short- and long-term stratospheric impact of smoke from the 2019–2020 Australian wildfires
<p>At the end of December 2019 and beginning of 2020, massive firestorms in Australia formed pyrocumulonimbus clouds (pyroCbs) that acted like enormous smokestacks, pumping smoke to the upper troposphere and stratosphere. We study the smoke with data from four satellite-based sensors: the aero...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-10-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/23/12557/2023/acp-23-12557-2023.pdf |
| _version_ | 1827796830842257408 |
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| author | J. Friberg B. G. Martinsson M. K. Sporre |
| author_facet | J. Friberg B. G. Martinsson M. K. Sporre |
| author_sort | J. Friberg |
| collection | DOAJ |
| description | <p>At the end of December 2019 and beginning of 2020,
massive firestorms in Australia formed pyrocumulonimbus clouds (pyroCbs) that
acted like enormous smokestacks, pumping smoke to the upper troposphere and
stratosphere. We study the smoke with data from four satellite-based
sensors: the aerosol observation platforms CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization), OMPS-LP (Ozone Mapping and Profiler Suite Limb Profiler), and OMPS-NM (Ozone Mapping and Profiler Suite Nadir Mapper) and
water vapor retrievals from MLS (Microwave Limb Sounder). Smoke was lofted to the upper troposphere
and stratosphere during two events and spread almost exclusively within the
extratropics. Smoke from the first event, starting 29 December, was injected
directly into the stratosphere by pyroCbs, causing a rapid initial increase
in AOD (aerosol optical depth). CALIOP identifies a rapid decline in this stratospheric smoke
(half-life: 10 d), not captured in previous studies of the Australian
fires, indicating photochemical processing of organic aerosol. This decay
rate is in line with model predictions of mid-tropospheric organic aerosol
loss by photolytic removal and is in agreement with our estimates of decay
rates after the North American fires in August 2017. PyroCbs from the second
event, 4 January, injected small amounts of smoke directly into the
stratosphere. Large amounts of smoke were injected to the upper troposphere,
from where it ascended into the stratosphere during several weeks, forming a
second peak in the aerosol load. Hence, we find that pyroCbs can impact the
stratospheric aerosol load both via direct injection to the stratosphere
and through injection of smoke to the upper troposphere from where the smoke
ascends into the stratosphere. The stratospheric AOD from the second-event
fires decreased more slowly than the AOD from the first event, likely due to a
combination of photolytic loss starting already in the troposphere and
continued supply of smoke from the upper troposphere offsetting the loss
rate. Together these injections yielded a major increase in the aerosol load
for almost 1 year.</p> |
| first_indexed | 2024-03-11T19:11:38Z |
| format | Article |
| id | doaj.art-ea84205e20004e93ac815b1e14b2858f |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-03-11T19:11:38Z |
| publishDate | 2023-10-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-ea84205e20004e93ac815b1e14b2858f2023-10-09T13:26:13ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242023-10-0123125571257010.5194/acp-23-12557-2023Short- and long-term stratospheric impact of smoke from the 2019–2020 Australian wildfiresJ. FribergB. G. MartinssonM. K. Sporre<p>At the end of December 2019 and beginning of 2020, massive firestorms in Australia formed pyrocumulonimbus clouds (pyroCbs) that acted like enormous smokestacks, pumping smoke to the upper troposphere and stratosphere. We study the smoke with data from four satellite-based sensors: the aerosol observation platforms CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization), OMPS-LP (Ozone Mapping and Profiler Suite Limb Profiler), and OMPS-NM (Ozone Mapping and Profiler Suite Nadir Mapper) and water vapor retrievals from MLS (Microwave Limb Sounder). Smoke was lofted to the upper troposphere and stratosphere during two events and spread almost exclusively within the extratropics. Smoke from the first event, starting 29 December, was injected directly into the stratosphere by pyroCbs, causing a rapid initial increase in AOD (aerosol optical depth). CALIOP identifies a rapid decline in this stratospheric smoke (half-life: 10 d), not captured in previous studies of the Australian fires, indicating photochemical processing of organic aerosol. This decay rate is in line with model predictions of mid-tropospheric organic aerosol loss by photolytic removal and is in agreement with our estimates of decay rates after the North American fires in August 2017. PyroCbs from the second event, 4 January, injected small amounts of smoke directly into the stratosphere. Large amounts of smoke were injected to the upper troposphere, from where it ascended into the stratosphere during several weeks, forming a second peak in the aerosol load. Hence, we find that pyroCbs can impact the stratospheric aerosol load both via direct injection to the stratosphere and through injection of smoke to the upper troposphere from where the smoke ascends into the stratosphere. The stratospheric AOD from the second-event fires decreased more slowly than the AOD from the first event, likely due to a combination of photolytic loss starting already in the troposphere and continued supply of smoke from the upper troposphere offsetting the loss rate. Together these injections yielded a major increase in the aerosol load for almost 1 year.</p>https://acp.copernicus.org/articles/23/12557/2023/acp-23-12557-2023.pdf |
| spellingShingle | J. Friberg B. G. Martinsson M. K. Sporre Short- and long-term stratospheric impact of smoke from the 2019–2020 Australian wildfires Atmospheric Chemistry and Physics |
| title | Short- and long-term stratospheric impact of smoke from the 2019–2020 Australian wildfires |
| title_full | Short- and long-term stratospheric impact of smoke from the 2019–2020 Australian wildfires |
| title_fullStr | Short- and long-term stratospheric impact of smoke from the 2019–2020 Australian wildfires |
| title_full_unstemmed | Short- and long-term stratospheric impact of smoke from the 2019–2020 Australian wildfires |
| title_short | Short- and long-term stratospheric impact of smoke from the 2019–2020 Australian wildfires |
| title_sort | short and long term stratospheric impact of smoke from the 2019 2020 australian wildfires |
| url | https://acp.copernicus.org/articles/23/12557/2023/acp-23-12557-2023.pdf |
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