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Apportionment and Inventory Optimization of Agriculture and Energy Sector Methane Emissions using Multi-month Trace Gas Measurements in Northern Colorado
  • +6
  • Griffin J Mead,
  • Daniel I Herman,
  • Fabrizio R Giorgetta,
  • Nathan A Malarich,
  • Esther Baumann,
  • Brian R Washburn,
  • Nathan R Newbury,
  • Ian Coddington,
  • Kevin C Cossel
Griffin J Mead
National Institute of Standards and Technology, Spectrum Technology and Research Division

Corresponding Author:[email protected]

Author Profile
Daniel I Herman
National Institute of Standards and Technology, Spectrum Technology and Research Division
Fabrizio R Giorgetta
National Institute of Standards and Technology, Spectrum Technology and Research Division
Nathan A Malarich
National Institute of Standards and Technology, Spectrum Technology and Research Division
Esther Baumann
National Institute of Standards and Technology, Spectrum Technology and Research Division
Brian R Washburn
National Institute of Standards and Technology, Spectrum Technology and Research Division
Nathan R Newbury
National Institute of Standards and Technology, Spectrum Technology and Research Division
Ian Coddington
National Institute of Standards and Technology, Spectrum Technology and Research Division
Kevin C Cossel
National Institute of Standards and Technology, Spectrum Technology and Research Division

Abstract

Quantifying sector-resolved methane fluxes in complex emissions environments is challenging yet necessary for inventory validations.  We separate energy and agriculture sector methane using a dynamic linear model of methane, ethane, and ammonia mixing ratios measured at a Northern Colorado site from November 2021 to January 2022. Combining observations with spatially resolved inventories and inverse methods, energy and agriculture methane fluxes are constrained across a ~850 km2 area. Optimized energy sector fluxes were 22% lower than the inventory despite a ~360% increase in regional energy production since the inventory was constructed, suggesting a regional decline in emissions factors. In contrast, optimized agriculture fluxes were 3× larger than the inventory; we demonstrate this discrepancy is consistent with the spatial distribution of agricultural sources. These results highlight the utility of sector-apportioned methane observations for multi-sector inventory optimization in complex environments, which may prove valuable for national and global quantification of sector-resolved methane fluxes.
25 May 2023Submitted to ESS Open Archive
31 May 2023Published in ESS Open Archive