English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Global: Zendy Plus monthly

Abstract. Forest fires in British Columbia in August 2017 caused apyrocumulonimbus event that injected a polluted air mass into thelower stratosphere. The Microwave Limb Sounder (MLS) on the Aurasatellite first observed the polluted air mass on 14 August 2017 andcontinued to observe it for 60 d (100 d in water vapour). Weestimate the mass of CO injected into the stratosphere to be2400 Gg. Events in which a fire injects its burning productsdirectly into the stratosphere are rare: this is the third of foursuch events in the 16 years since the launch of Aura, thesecond largest of the four events, and the only one in the NorthernHemisphere. The other three events occurred in Australia in December2006, February 2009 and from December 2019 to January 2020. Unlikethe 2006 and 2009 events, but like the 2019–2020 event, the pollutedair mass described here had a clearly elevated water vapour content:between 2.5 and 5 times greater than that in the surroundingatmosphere. We describe the evolution of the polluted air mass,showing that it rose to an altitude of about 24 km (31 hPa) anddivided into several identifiable parts. In addition to CO andH2O, we observe enhanced amounts of HCN, CH3CN, CH3Cl andCH3OH with mixing ratios in the range to be expected from avariety of measurements in other biomass burning plumes. We useback trajectories and plume-dispersion modelling to demonstrate thatthe pollutants observed by MLS originated in the British Columbiafires, the likeliest source being at 53.2∘ N, 121.8∘ Wat 05:20 UTC on 13 August 2017.

Microwave Limb Sounder (MLS) observations of biomass burning products in the stratosphere from Canadian forest fires in August 2017