A049-01
Australian wildfires caused a major perturbation of the stratosphere and generate a smoke-charged vortex rising up to 35 km as inferred from satellite observations
Tuesday, 8 December 2020: 10:30
Virtual
Sergey Khaykin1, Bernard Legras2, Silvia Bucci3, Pasquale Sellitto4, Lars Isaksen5, Florent Tence6, Slimane Bekki7, Adam E Bourassa8, Landon A Rieger9, Daniel Zawada9, Julien Jumelet6 and Sophie Godin-Beekmann6, (1)LATMOS/IPSL, UVSQ, Sorbonne Université, CNRS, Paris Cedex 05, France, (2)Laboratoire de Météorologie Dynamique ENS, Paris, France, (3)National Research Council (CNR), Institute of Atmospheric Sciences and Climate (ISAC), Rome, Italy, (4)LISA Laboratoire Interuniversitaire des Systèmes Atmosphériques, Créteil Cedex, France, (5)European Center for Medium-Range Weather Forecasts, Reading, United Kingdom, (6)LATMOS Laboratoire Atmosphères, Milieux, Observations Spatiales, Paris Cedex 05, France, (7)LATMOS Laboratoire Atmosphères, Milieux, Observations Spatiales, Guyancourt, France, (8)University of Saskatchewan, Department of Physics & Engineering Physics, Saskatoon, SK, Canada, (9)University of Saskatchewan, Saskatoon, SK, Canada
Abstract:
Wildfire-driven pyro-convection (PyroCb) is capable of lifting combustion products into the stratosphere, polluting it with smoke at hemispheric and monthly scales and producing an impact comparable to that of moderate volcanic eruptions. The Australian bushfires that raged around the turn of the year 2020 have put a new benchmark on the magnitude of stratospheric perturbations. Here we exploit a synergy of various satellite observations (OMPS-LP, MLS, CALIOP, TROPOMI, SAGE III and Aeolus space wind lidar), UVSPEC radiative transfer model together with the Integrated Forecasting System (IFS) of ECMWF to quantify the perturbation of stratospheric particulate and gaseous composition, radiative balance and dynamical circulation.
We show that the resulting planetary-scale perturbation of stratospheric aerosol load produced by the PyroCb outbreak on the New Year’s eve has by far eclipsed the effects of all the documented wildfires events and rivaled the strongest volcanic eruptions in the post-Pinatubo era in terms of global-equivalent radiative forcing on the surface. The increase of the stratospheric mass of CO and H2O within the southern extratropics has reached approximately 20% and 3% in the months following the event.
A striking effect of the solar heating of an intense smoke patch was the generation of several self-maintained anticyclonic vortices, accompanied by synoptic scale ozone holes with total column reduction by up to 100 DU. The most intense vortex measured 1000 km in diameter and persisted in the stratosphere for over 13 weeks, travelling over 66,000 km and gradually lifted a confined bubble of smoke and moisture to 35 km altitude. The evolution of the bubble was precisely tracked by several satellite-based sensors and by the ECMWF model assimilating GNSS-RO temperature profiling data. This points out a remarkable capacity of the modern observational and modeling systems to monitor an unprecedented phenomenon as well as a strong complementarity between the North American and European space missions. 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.
https://arxiv.org/pdf/2006.07284
