Rising smoke-charged vortices in the mid-latitude stratosphere

The two most intense wildfires of the last decade that took place in Canada in 2017 and Australia in 2019-2020 were followed by large injections of smoke in the stratosphere due to pyroconvection. It was discovered that, after the Australian event, part of this smoke self-organized as anticyclonic confined vortices that rose against the Brewer-Dobson circulation in the mid-latitude stratosphere up to 35 km (Khaykin et al., 2020, doi: 10.1038/s43247-020-00022-5).  Based on CALIOP lidar observations and the ECMWF ERA5 reanalysis, we analyze the Canadian case and find, similarly, that the large plume which penetrated the stratosphere on 12 August 2017 and reached 14 km got trapped thereafter within a meso-scale anticyclonic structure which travelled across the Atlantic. It then broke into three offsprings that could be followed until mid-October 2017, each performing  round the world journeys and rising up to 23 km for one of them. We analyze the dynamical structure of the vortices produced by these two wildfires in the ERA 5 and demonstrate how they are maintained by the assimilation of data from instruments measuring the signature of the vortices in the temperature and ozone field. We propose that these vortices can be seen as bubbles of very low potential vorticity carried vertically by their internal radiative heating across the stratosphere against the stratification. We will also present elements of a theory and first numerical simulations explaining the dynamics of such structures  and discuss possible occurrences after other forest fires and volcanic eruptions in the past as well as  future likely impacts. This new phenomenon in geophysical fluid mechanics has, to our knowledge, no reported analog (see reference: https://acp.copernicus.org/preprints/acp-2020-1201/).