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Lofting and Circumnavigation of Biomass Burning Aerosols and Carbon Monoxide from a North American Wildfire in October 2020

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journal contribution
posted on 05.02.2021, 19:39 by Changqing Lin, Yinghua Zhang
Hemispheric transport events of air pollutants from North American wildfires are not common. On 22 October 2020, the exceptionally intense East Troublesome Fire in the Rocky Mountains injected a huge mass of air pollutant mixtures including biomass burning aerosols and carbon monoxide into the atmosphere. In this study, we used atmospheric sounding to explore atmospheric stability and lofting of the pollutant mixtures. We then took advantage of multisatellite measurements (e.g., reflectance data from Moderate Resolution Imaging Spectroradiometer (MODIS), ultraviolet aerosol index from Ozone Mapping Profiler Suite (OMPS), carbon monoxide concentration from Atmospheric Infrared Sounder (AIRS), and atmospheric vertical structure from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO)) to track the three-dimensional long-range transport of pollutant mixtures. Near the pollution source, a deep neutral layer lay above a stable temperature inversion layer. The heated plume released in the neutral layer resulted in a lofting of the pollutant mixtures into the westerly jet stream in the upper troposphere, with an injection height ranging from 8 to 13 km. The pollutant mixtures were then transported eastwards by the westerly winds in the upper troposphere and lower stratosphere during different periods of its evolution. The pollutant mixtures arrived in the upper air over East Asia after 8 days of transport from the source. A part of the smoke circumnavigated the globe and returned to the upper air over North America after 14 days. These results indicate that hemispheric transport of the combustion products from wildfires occurs when atmospheric stability favors the lofting of air pollutants into a jet stream in the upper troposphere.