AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
The Ubiquity of Biomass Burning Particles in the Global Remote Troposphere
GREGORY SCHILL, Karl D. Froyd, Daniel Murphy, Christina Williamson, Agnieszka Kupc, Charles Brock, Huisheng Bian, Mian Chin, Peter Colarco, Eric Ray, Alan Hills, Rebecca Hornbrook, Eric Apel, NOAA ESRL and CIRES, University of Colorado Boulder
Abstract Number: 498 Working Group: Biomass Combustion: Emissions, Chemistry, Air Quality, Climate, and Human Health
Abstract Wildfires and open burning emit ~2.8 Tg of black carbon (BC) and ~31 Tg of primary organic aerosol (POA) every year. These estimates correspond to ~40% of global BC and ~60% of global POA emissions, with larger contributions if solid-fuel heating and cooking are included. Thus, biomass burning aerosol have immense potential to affect the Earth’s climate system via both the aerosol direct and indirect effects. Despite this importance, there are few observational constraints on the global abundance of biomass burning particles. In particular, in-situ measurements in the global remote troposphere, far from biomass burning emissions, are almost entirely absent.
In this work, we provide the first seasonally resolved, global maps of biomass burning aerosol abundance from aircraft observations. Measurements were taken during the NASA Atmospheric Tomography (ATom) mission during 2016-2018. During ATom, nearly continuous altitude profiles (~0.15 to 12 km) of single-particle composition were measured by PALMS from 86°S to 82°N, primarily over the remote oceans. Despite oftentimes being thousands of km from biomass burning sources, we find that biomass burning particles make up 12-50% [interquartile range (IQR)] of the accumulation mode particle number and 11-40% (IQR) of the aerosol mass from 2 to 8 km in the remote troposphere. Comparisons of ATom observations to the GEOS-5 model indicates biomass burning aerosol wet removal processes are underestimated. Using an updated model, we estimate the climatic significance of biomass burning in the remote troposphere. We find that, on a monthly average, 37-68% of the AOD from biomass burning (globally summed) can be attributed to this ubiquitous smoke outside of defined biomass burning plumes.