Australia’s Black Summer pyrocumulonimbus super outbreak reveals potential for increasingly extreme stratospheric smoke events

Peterson, David A.; Fromm, M.; McRae, Rick; Campbell, James; Hyer, E. J.; Taha, Ghassan; Camacho, C. P.; Kablick, George P.; Schmidt, C. C.; DeLand, Matthew T.

doi:10.1038/s41612-021-00192-9

Cited by 98 publications

(149 citation statements)

References 76 publications

Supporting

Mentioning

139

Contrasting

Order By: Relevance

“…This time, the CALIPSO aerosol typing scheme successfully classified the detected stratospheric aerosol as wildfire smoke from Australia. The smoke was lifted over southeastern Australia by pyroCb convection to roughly 15 km height before starting the longrange travel over 10,000 km across the Pacific Ocean to South America (Figure 1) (Ohneiser et al, 2020;Peterson et al, 2021). The 532 nm AOT of the 2-km thick smoke layer, initially centered at 4 km height, was assumed to be 0.5, 1.0, and 1.5.…”

Section: A Successful Identification: Australianmentioning

confidence: 99%

CALIPSO Aerosol-Typing Scheme Misclassified Stratospheric Fire Smoke: Case Study From the 2019 Siberian Wildfire Season

Ansmann

Ohneiser

Chudnovsky

et al. 2021

Front. Environ. Sci.

View full text Add to dashboard Cite

In August 2019, a 4-km thick wildfire smoke layer was observed in the lower stratosphere over Leipzig, Germany, with a ground-based multiwavelength Raman lidar. The smoke was identified by the smoke-specific spectral dependence of the extinction-to-backscatter ratio (lidar ratio) measured with the Raman lidar. The spaceborne CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) lidar CALIOP (Cloud–Aerosol Lidar with Orthogonal Polarization) detected the smoke and classified it as sulfate aerosol layer (originating from the Raikoke volcanic eruption). In this article, we discuss the reason for this misclassification. Two major sources for stratospheric air pollution were active in the summer of 2019 and complicated the CALIPSO aerosol typing effort. Besides intense forest fires at mid and high northern latitudes, the Raikoke volcano erupted in the Kuril Islands. We present two cases observed at Leipzig, one from July 2019 and one from August 2019. In July, pure volcanic sulfate aerosol layers were found in the lower stratosphere, while in August, wildfire smoke dominated in the height range up to 4–5 km above the local tropopause. In both cases, the CALIPSO aerosol typing scheme classified the layers as sulfate aerosol layers. The aerosol identification algorithm assumes non-spherical smoke particles in the stratosphere as consequence of fast lifting by pyrocumulonimbus convection. However, we hypothesize (based on presented simulations) that the smoke ascended as a results of self-lifting and reached the tropopause within 2–7 days after emission and finally entered the lower stratosphere as aged spherical smoke particles. These sphercial particles were then classified as liquid sulfate particles by the CALIPSO data analysis scheme. We also present a successful case of smoke identification by the CALIPSO retrieval method.

show abstract

Section: A Successful Identification: Australianmentioning

confidence: 99%

CALIPSO Aerosol-Typing Scheme Misclassified Stratospheric Fire Smoke: Case Study From the 2019 Siberian Wildfire Season

Ansmann

Ohneiser

Chudnovsky

et al. 2021

Front. Environ. Sci.

View full text Add to dashboard Cite

show abstract

“…PNE comprised less than 10 pyroCb pulses, however caused the largest smoke-related stratospheric perturbation ever observed over Europe (Ansmann et al, 2018;Baars et al, 2019). ANYSO's first phase stands as the largest known stratospheric injection of smoke particles linked to a distinct period of pyroCb activity (0.2-0.8 Tg) (Peterson et al, 2021). ANYSO's second phase injected an estimated 0.1-0.3 Tg of additional smoke particle mass into the lower stratosphere.…”

Section: Coral Observations At Río Grande Argentinamentioning

confidence: 99%

“…Extremely strong and long-lasting bushfires in southeastern Australia (Boer et al, 2020) in combination with extraordinarily strong pyrocumulonimbus (pyroCb) activity at the end of December 2019 and in the beginning of January 2020 induced a major perturbation of the stratospheric aerosol conditions (Peterson et al, 2021). The smoke dispersed over most parts of the Southern Hemisphere, including Antarctica (Tencé et al, 2021), and reached heights up to 35 km (Khaykin et al, 2020;Kablick et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

“…The smoke dispersed over most parts of the Southern Hemisphere, including Antarctica (Tencé et al, 2021), and reached heights up to 35 km (Khaykin et al, 2020;Kablick et al, 2020). The Black Summer fire season of 2019-2020 in southeastern Australia, denoted as Australian New Year Super Outbreak (ANYSO) event by Peterson et al (2021) caused a three times higher stratospheric aerosol mass of injected smoke than the record-breaking Canadian wildfires (Pacific Northwest Event, PNE) in the Northern Hemisphere in August 2017 (Peterson et al, 2018). The latter led to the largest stratospheric perturbation by smoke over Germany (Ansmann et al, 2018) and Europe (Baars et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…The potential of smoke to ascend over several months by heating the air due to strong light absorption is an important aspect that significantly prolongs the residence time of wildfire smoke in the stratosphere. As Peterson et al (2021) pointed out, the 'diabatic lofting' effect is often strong enough to oppose the mean downward motion, ultimately increasing plume lifetime in the stratosphere. Several ANYSO smoke ascended from initial injection heights of 14-17 km to about 35 km within 40 days (Khaykin et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Australian wildfire smoke in the stratosphere: the decay phase in 2020/21 and impact on ozone depletion

Ohneiser¹,

Ansmann²,

Kaifler³

et al. 2022

Preprint

View full text Add to dashboard Cite

Abstract. 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 μm2 cm−3.

show abstract

Stratospheric water vapor and ozone response to different QBO disruption events in 2016 and 2020

Diallo

Ploeger

Hegglin

et al. 2022

Preprint

View full text Add to dashboard Cite

The Quasi-Biennial Oscillation (QBO) is a major mode of climate variability with periodically descending westerly and easterly winds in the tropical stratosphere, modulating transport and distributions of key greenhouse gases such as water vapor and ozone. In 2016 and 2020, anomalous QBO easterlies disrupted the QBO's 28-month period previously observed.Here, we quantify the impact of these two QBO disruption events on the Brewer-Dobson circulation, water vapour and ozone using the ERA5 reanalysis and satellite observations, respectively. Both lower stratospheric trace gases decrease globally during the 2015-2016 QBO disruption event, while they only weakly decrease during the 2019-2020 QBO disruption event.These dissimilarities in the circulation anomalous response to the QBO disruption events result from differences in the tropical upwelling caused by anomalous planetary and gravity wave forcing in the lower stratosphere near the equatorward flanks of the subtropical jet. The differences in the response of lower stratospheric water vapor to the 2015-2016 and 2019-2020 QBO disruption events are due to the cold-point temperature differences induced by the Australian wildfire, which moistened the lower stratosphere, therefore, hidding the 2019-2020 QBO disruption impact. Our results highlight the need for a better understanding of the causes of QBO disruption events, their interplay with other climate variability modes, and their impacts on water vapor and ozone in the face of a changing climate.

show abstract

Australia’s Black Summer pyrocumulonimbus super outbreak reveals potential for increasingly extreme stratospheric smoke events

Cited by 98 publications

References 76 publications

CALIPSO Aerosol-Typing Scheme Misclassified Stratospheric Fire Smoke: Case Study From the 2019 Siberian Wildfire Season

CALIPSO Aerosol-Typing Scheme Misclassified Stratospheric Fire Smoke: Case Study From the 2019 Siberian Wildfire Season

Australian wildfire smoke in the stratosphere: the decay phase in 2020/21 and impact on ozone depletion

Stratospheric water vapor and ozone response to different QBO disruption events in 2016 and 2020

Contact Info

Product

Resources

About