Australian wildfire smoke in the stratosphere: the decay phase in 2020/21 and impact on ozone depletion
Record-breaking wildfires raged in southeastern Australia in late December 2019 and early January 2020. Rather strong pyrocumulonimbus (pyroCb) convection developed over the fire areas and lifted enormous amounts of biomass-burning smoke into the tropopause region and caused the strongest wildfire-r...
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ftcopernicus:oai:publications.copernicus.org:acpd100535 2023-05-15T14:02:17+02:00 Australian wildfire smoke in the stratosphere: the decay phase in 2020/21 and impact on ozone depletion Ohneiser, Kevin Ansmann, Albert Kaifler, Bernd Chudnovsky, Alexandra Barja, Boris Knopf, Daniel A. Kaifler, Natalie Baars, Holger Seifert, Patric Villanueva, Diego Jimenez, Cristofer Radenz, Martin Engelmann, Ronny Veselovskii, Igor Zamorano, Felix 2022-01-18 application/pdf https://doi.org/10.5194/acp-2021-1097 https://acp.copernicus.org/preprints/acp-2021-1097/ eng eng doi:10.5194/acp-2021-1097 https://acp.copernicus.org/preprints/acp-2021-1097/ eISSN: 1680-7324 Text 2022 ftcopernicus https://doi.org/10.5194/acp-2021-1097 2022-01-24T17:22:16Z Record-breaking wildfires raged in southeastern Australia in late December 2019 and early January 2020. Rather strong pyrocumulonimbus (pyroCb) convection developed over the fire areas and lifted enormous amounts of biomass-burning smoke into the tropopause region and caused the strongest wildfire-related stratospheric aerosol perturbation ever observed around the globe. We discuss the geometrical, optical, and microphyscial properties of the stratospheric smoke layers and the decay of this major stratospheric perturbation. A multiwavelength polarization Raman lidar at Punta Arenas (53.2° S, 70.9° W), southern Chile, and an elastic-backscatter Raman lidar at Río Grande (53.8° S, 67.7° W) in southern Argentina were operated to monitor the major record-breaking event until the end of 2021. These lidar measurements can be regarded as representative for mid to high latitudes in the Southern Hemisphere. A unique dynamical feature, an anticyclonic, smoke-filled vortex with 1000 km horizontal width and 5 km vertical extent, which ascended by about 500 m per day, was observed over the full last week of January 2020. The key results of the long-term study are as follows: The smoke layers extended, on average, from 9 to 24 km in height. The smoke partly ascended to more than 30 km height as a result of self-lifting processes. Clear signs of a smoke impact on the record-breaking ozone hole over Antarctica in September–November 2020 were found. A slow decay of the stratospheric perturbation detected by means of the 532 nm aerosol optical thickness (AOT) yielded an e-folding decay time of 19–20 months. The maximum smoke AOT was around 1.0 over Punta Arenas in January 2020 and thus two to three orders of magnitude above the stratospheric aerosol background of 0.005. After two months with strongly varying smoke conditions, the 532 nm AOT decreased to 0.03–0.06 from March–December 2020 and to 0.015–0.03 throughout 2021. The particle extinction coefficients were in the range of 10–75 Mm −1 in January 2020, and later on mostly between 1 and 5 Mm −1 . Combined lidar-photometer retrievals revealed typical smoke extinction-to-backscatter ratios of 69 ±19 sr (at 355 nm), 91 ± 17 sr (at 532 nm), and 120 ± 22 sr (at 1064 nm). An ozone reduction of 20–25 % in the 15–22 km height range was observed over Antarctic and New Zealand ozonesonde stations in the smoke-polluted air with particle surface area concentrations of 1–5 μ m 2 cm −3 . Text Antarc* Antarctic Antarctica Copernicus Publications: E-Journals Antarctic Argentina New Zealand |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Record-breaking wildfires raged in southeastern Australia in late December 2019 and early January 2020. Rather strong pyrocumulonimbus (pyroCb) convection developed over the fire areas and lifted enormous amounts of biomass-burning smoke into the tropopause region and caused the strongest wildfire-related stratospheric aerosol perturbation ever observed around the globe. We discuss the geometrical, optical, and microphyscial properties of the stratospheric smoke layers and the decay of this major stratospheric perturbation. A multiwavelength polarization Raman lidar at Punta Arenas (53.2° S, 70.9° W), southern Chile, and an elastic-backscatter Raman lidar at Río Grande (53.8° S, 67.7° W) in southern Argentina were operated to monitor the major record-breaking event until the end of 2021. These lidar measurements can be regarded as representative for mid to high latitudes in the Southern Hemisphere. A unique dynamical feature, an anticyclonic, smoke-filled vortex with 1000 km horizontal width and 5 km vertical extent, which ascended by about 500 m per day, was observed over the full last week of January 2020. The key results of the long-term study are as follows: The smoke layers extended, on average, from 9 to 24 km in height. The smoke partly ascended to more than 30 km height as a result of self-lifting processes. Clear signs of a smoke impact on the record-breaking ozone hole over Antarctica in September–November 2020 were found. A slow decay of the stratospheric perturbation detected by means of the 532 nm aerosol optical thickness (AOT) yielded an e-folding decay time of 19–20 months. The maximum smoke AOT was around 1.0 over Punta Arenas in January 2020 and thus two to three orders of magnitude above the stratospheric aerosol background of 0.005. After two months with strongly varying smoke conditions, the 532 nm AOT decreased to 0.03–0.06 from March–December 2020 and to 0.015–0.03 throughout 2021. The particle extinction coefficients were in the range of 10–75 Mm −1 in January 2020, and later on mostly between 1 and 5 Mm −1 . Combined lidar-photometer retrievals revealed typical smoke extinction-to-backscatter ratios of 69 ±19 sr (at 355 nm), 91 ± 17 sr (at 532 nm), and 120 ± 22 sr (at 1064 nm). An ozone reduction of 20–25 % in the 15–22 km height range was observed over Antarctic and New Zealand ozonesonde stations in the smoke-polluted air with particle surface area concentrations of 1–5 μ m 2 cm −3 . |
format |
Text |
author |
Ohneiser, Kevin Ansmann, Albert Kaifler, Bernd Chudnovsky, Alexandra Barja, Boris Knopf, Daniel A. Kaifler, Natalie Baars, Holger Seifert, Patric Villanueva, Diego Jimenez, Cristofer Radenz, Martin Engelmann, Ronny Veselovskii, Igor Zamorano, Felix |
spellingShingle |
Ohneiser, Kevin Ansmann, Albert Kaifler, Bernd Chudnovsky, Alexandra Barja, Boris Knopf, Daniel A. Kaifler, Natalie Baars, Holger Seifert, Patric Villanueva, Diego Jimenez, Cristofer Radenz, Martin Engelmann, Ronny Veselovskii, Igor Zamorano, Felix Australian wildfire smoke in the stratosphere: the decay phase in 2020/21 and impact on ozone depletion |
author_facet |
Ohneiser, Kevin Ansmann, Albert Kaifler, Bernd Chudnovsky, Alexandra Barja, Boris Knopf, Daniel A. Kaifler, Natalie Baars, Holger Seifert, Patric Villanueva, Diego Jimenez, Cristofer Radenz, Martin Engelmann, Ronny Veselovskii, Igor Zamorano, Felix |
author_sort |
Ohneiser, Kevin |
title |
Australian wildfire smoke in the stratosphere: the decay phase in 2020/21 and impact on ozone depletion |
title_short |
Australian wildfire smoke in the stratosphere: the decay phase in 2020/21 and impact on ozone depletion |
title_full |
Australian wildfire smoke in the stratosphere: the decay phase in 2020/21 and impact on ozone depletion |
title_fullStr |
Australian wildfire smoke in the stratosphere: the decay phase in 2020/21 and impact on ozone depletion |
title_full_unstemmed |
Australian wildfire smoke in the stratosphere: the decay phase in 2020/21 and impact on ozone depletion |
title_sort |
australian wildfire smoke in the stratosphere: the decay phase in 2020/21 and impact on ozone depletion |
publishDate |
2022 |
url |
https://doi.org/10.5194/acp-2021-1097 https://acp.copernicus.org/preprints/acp-2021-1097/ |
geographic |
Antarctic Argentina New Zealand |
geographic_facet |
Antarctic Argentina New Zealand |
genre |
Antarc* Antarctic Antarctica |
genre_facet |
Antarc* Antarctic Antarctica |
op_source |
eISSN: 1680-7324 |
op_relation |
doi:10.5194/acp-2021-1097 https://acp.copernicus.org/preprints/acp-2021-1097/ |
op_doi |
https://doi.org/10.5194/acp-2021-1097 |
_version_ |
1766272482187149312 |