EGU21-9645, updated on 09 Jun 2021
https://doi.org/10.5194/egusphere-egu21-9645
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Striking repercussions of the Australian "Black Summer" bushfires on the stratospheric composition and dynamical circulation

Sergey Khaykin1, Bernard Legras2, Silvia Bucci2,3, Pasquale Sellitto4, Lars Isaksen5, Florent Tencé1, Slimane Bekki1, Adam Bourassa6, Landon Rieger6, Daniel Zawada6, Julien Jumelet1, and Sophie Godin-Beekmann1
Sergey Khaykin et al.
  • 1LATMOS, CNRS, IPSL, UVSQ/Sorbonne Univ, Guyancourt, France (sergey.khaykin@latmos.ipsl.fr)
  • 2Laboratoire de Météorologie Dynamique, CNRS , IPSL, PSL-ENS/Sorbonne Univ./Ecole Polytechnique, Paris, France (bernard.legras@lmd.ipsl.fr)
  • 3University of Vienna, Vienna, Austria (silvia.bucci@lmd.ipsl.fr)
  • 4Laboratoire Interuniversitaire des Systèmes Atmosphériques, CNRS, IPSL, Université Paris-Est Créteil/Université de Paris, Créteil, France (pasquale.sellitto@lisa.ipsl.fr)
  • 5European Centre for Medium-Range Weather Forecasts, Reading, UK (Lars.Isaksen@ecmwf.int)
  • 6Institute of Space and Atmospheric Studies, University of Saskatchewan, Saskatoon, Canada (adam.bourassa@usask.ca)

Wildfire-driven pyro-convection (PyroCb) is capable of lofting combustion products into the stratosphere, polluting it with smoke aerosols at hemispheric and yearly scales. This realization has emerged after the record-breaking British Columbia PyroCb event in August 2017 that approached moderate volcanic eruptions in terms of stratospheric aerosol load perturbation. The Australian “Black Summer” bushfires in 2019/20 have surpassed the previous record by a factor of 3 and rivaled the strongest volcanic eruptions in the XXI century. Here we exploit a synergy of various satellite observations, ECMWF meteorological analysis and radiative transfer modeling to quantify the perturbation of stratospheric particulate and gaseous composition, dynamical circulation and radiative balance caused by the Australian New Year’s PyroCb outbreak. One of the most striking repercussions of this event was the generation of several persistent anticyclonic vortices that provided confinement to the PyroCb plumes and preserved them from rapid dilution in the environment. The most intense vortex measured 1000 km in diameter, persisted in the stratosphere for over 13 weeks and lifted a confined bubble of combustion gases, aerosols and moisture to 35 km altitude. It was accompanied by a synoptic-scale ozone hole with the total column reduction by about 30%. The startling consequences of the Australian event provide new insights into climate-altering potential of the wildfires, that have increased in frequency and strength over the recent years.

How to cite: Khaykin, S., Legras, B., Bucci, S., Sellitto, P., Isaksen, L., Tencé, F., Bekki, S., Bourassa, A., Rieger, L., Zawada, D., Jumelet, J., and Godin-Beekmann, S.: Striking repercussions of the Australian "Black Summer" bushfires on the stratospheric composition and dynamical circulation, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9645, https://doi.org/10.5194/egusphere-egu21-9645, 2021.

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