Australian wildfires cause major perturbation of the stratosphere and generate a self-maintained smoke-charged vortex rising up to 35 km 

Sergey Khaykin (1) , Bernard Legras (2) , Silvia Bucci (2) , Pasquale Sellitto (3) , Lars Isaksen (4) , Florent Tence (1) , Slimane Bekki (1) , Adam E Bourassa (5) , Landon A Rieger (5) , Daniel Zawada (5) , Julien Jumelet (1) , Sophie Godin-Beekmann (1)

1 STRATO - LATMOS
2 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
3 LISA (UMR_7583) - Laboratoire Interuniversitaire des Systèmes Atmosphériques
4 ECMWF - European Centre for Medium-Range Weather Forecasts
5 U of S - University of Saskatchewan [Saskatoon, Canada]

Wildfire-driven pyro-convection 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 infrequent 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 show that the resulting planetary-scale blocking of solar radiation by the smoke has by far eclipsed the effects of all the documented wildfires events, exceeding the radiative forcing produced by moderate volcanic eruptions over the last three decades. A striking and unexpected effect of the solar heating of an intense smoke patch was the generation of a self-maintained quasi-ellipsoidal anticyclonic vortex measuring 1000 km in diameter and featuring its own ozone hole. The highly stable vortex 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. The vortex was also successfully resolved by the European Centre for Medium-Range Weather Forecasts (ECMWF) operational forecasting system [5], primarily based on radio occultation, temperature and ozone sensitive data from satellite instruments. This shows the outstanding capacity of the state-of-the-arts observing and modeling systems to identify, follow, and reproduce an unusual atmospheric phenomenon. 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 in the Northern Hemisphere. The unexpected dynamical repercussion is an important discovery for geophysical fluid dynamics

Domaines: Océan, Atmosphère

Sergey Khaykin, Bernard Legras, Silvia Bucci, Pasquale Sellitto, Lars Isaksen, et al.. Australian wildfires cause major perturbation of the stratosphere and generate a self-maintained smoke-charged vortex rising up to 35 km . 2020. ⟨hal-02865306v1⟩