Sergey Khaykin: Stratospheric impact of wildfires (2004 - 2025) from satellite and ground

Stratospheric impact of wildfires (2004 - 2025) from satellite and ground - based observations

Lecturer: Sergey Khaykin:
LATMOS/IPSL, CNRS UVSQ, Sorbonne Universites

Wildfires have intensified over recent decades, and there is an emerging recognition of their effect on climate and the ozone layer via emissions of smoke aerosols and other combustion products into the stratosphere. Intense wildfires give rise to extreme thunderstorms termed Pyrocumulonimbus (PyroCb). These storms can generate vigorous convective updrafts injecting smoke into the stratosphere, where the residence time of aerosol is not limited by cloud scavenging and precipitation. Recent studies show that strong PyroCb outbreaks can rival
explosive volcanic eruptions in magnitude and duration of stratospheric perturbation. PyroCb injections into the stratosphere were also shown to generate persistent synoptic-scale anticyclones (SCV – Smoke-Charged Vortex), lofting confined bubbles of smoke deep into the stratosphere due to solar heating of carbonaceous aerosols, which prolongs their atmospheric residence time and radiative effects.
Here we use global satellite observations (OMPS, TROPOMI, CALIPSO, SAGE III, MLS, Aeolus and EarthCARE missions) together with ground-based lidar observations (NDACC and ACTRIS networks) and meteorological analysis to characterize and quantify wildfire impacts on stratospheric aerosol and gaseous composition as well as to explore the evolution and dynamics of SCV anticyclones. We identify wildfire events from 2004–2025 with measurable stratospheric impact and classify them into four categories based on the mass of injected aerosols, estimated using satellite data. The longevity of smoke particles in the stratosphere is estimated using satellite and ground-based lidar
measurements of backscatter and depolarisation. 

A particular focus is made on the anomalous 2023 Boreal wildfire season, which stood out for its extended burned area and duration, by far exceeded the previous record-breaking events. Using satellite, airborne and ground-based observations together with MOCAGE CTM simulations constrained by GFAS emissions we put in evidence a non-PyroCb vertical pathway of smoke into the stratosphere through the
warm-conveyor-belt (WCB) mechanism. We show that the WCB-uplifted plumes are different from the PyroCB plumes in their structure and
habits, whereas the impact of WCB plumes is largest at the aircraft cruising altitudes.

Finally, we discuss the stratospheric impact of the panboreal wildfire outbreak in May 2025, involving several pyroCb injections across Canada
and eastern Siberia. Using ground-based lidars and EarthCARE ATLID, we explore the spatial evolution of stratospheric plumes and their
optical properties

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Meeting-ID: 695 8624 7201, Kenncode: 490572