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Seasonal Variability in Local Carbon Dioxide Combustion Sources over the Central and Eastern US using Airborne In-Situ Enhancement Ratios
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  • Joshua Paul DiGangi,
  • Yonghoon Choi,
  • John B. Nowak,
  • Hannah Selene Halliday,
  • Glenn S. Diskin,
  • Sha Feng,
  • Zachary Robert Barkley,
  • Thomas Lauvaux,
  • Sandip Pal,
  • Kenneth J. Davis,
  • Bianca C. Baier,
  • Colm Sweeney
Joshua Paul DiGangi
NASA Langley Research Center

Corresponding Author:[email protected]

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Yonghoon Choi
Science Systems and Applications, INC.
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John B. Nowak
NASA Langley Research Center
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Hannah Selene Halliday
EPA
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Glenn S. Diskin
NASA Langley Research Center
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Sha Feng
Pacific Northwest National Laboratory
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Zachary Robert Barkley
The Pennsylvania State University
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Thomas Lauvaux
Pennsylvania State University
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Sandip Pal
Department of Geosciences, Atmospheric Science Division, Texas Tech University
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Kenneth J. Davis
Pennsylvania State University
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Bianca C. Baier
University of Colorado Boulder
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Colm Sweeney
NOAA Global Monitoring Laboratory
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Abstract

We present observations of local enhancements in carbon dioxide (CO2) from local emissions sources over three eastern US regions during four deployments of the Atmospheric Carbon Transport-America (ACT-America) campaign between summer 2016 and spring 2018. Local CO2 emissions were characterized by carbon monoxide (CO) to CO2 enhancement ratios (i.e. ΔCO/ΔCO2) in airmass mixing observed during aircraft transects within the atmospheric boundary layer. By analyzing regional-scale variability of CO2 enhancements as a function of ΔCO/ΔCO2 enhancement ratios, observed relative contributions to CO2 emissions were contrasted between different combustion regimes across regions and seasons. Ninety percent of observed summer combustion in all regions was attributed to high efficiency fossil fuel (FF) combustion (ΔCO/ΔCO2 < 0.5%). In other seasons, regional contributions increased from less efficient forms of FF combustion (ΔCO/ΔCO2 0.5-2%) to as much as 60% of observed combustion. CO2 emission contributions attributed to biomass burning (BB) (ΔCO/ΔCO2 > 4%) were negligible during summer and fall in all regions, but climbed to 10-12% of observed combustion in the South during winter and spring. Vulcan v3 CO2 2015 emission analysis showed increases in residential and commercial sectors seasonally matching increases in less efficient FF combustion, but could not explain regional trends. WRF-Chem modeling, driven by CarbonTracker CO2 fire emissions, matched observed winter and spring BB contributions, but conflictingly predicted similar levels of BB during fall. Satellite fire data from MODIS and VIIRS suggested higher spatial resolution fire data might improve modeled BB emissions.