Comparison of Global Downscaled Versus Bottom-Up Fossil Fuel CO 2 Emissions at the Urban Scale in Four U.S. Urban Areas

Kevin Gurney, J. Liang, D. O'Keeffe, R. Patarasuk, M. Hutchins, J. Huang, P. Rao, Y. Song

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Spatiotemporally resolved urban fossil fuel CO 2 (FFCO 2 ) emissions are critical to urban carbon cycle research and urban climate policy. Two general scientific approaches have been taken to estimate spatiotemporally explicit urban FFCO 2 fluxes, referred to here as “downscaling” and “bottom-up.” Bottom-up approaches can specifically characterize the CO 2 -emitting infrastructure in cities but are labor-intensive to build and currently available in few U.S. cities. Downscaling approaches, often available globally, require proxy information to allocate or distribute emissions resulting in additional uncertainty. We present a comparison of a downscaled FFCO 2 emission data product (Open-source Data Inventory for Anthropogenic CO 2 (ODIAC)) to a bottom-up estimate (Hestia) in four U.S. urban areas in an effort to better isolate and understand differences between the approaches. We find whole-city differences ranging from −1.5% (Los Angeles Basin) to +20.8% (Salt Lake City). At the 1 km × 1 km spatial scale, comparisons reveal a low-emission limit in ODIAC driven by saturation of the nighttime light spatial proxy. At this resolution, the median difference between the two approaches ranged from 47 to 84% depending upon city with correlations ranging from 0.34 to 0.68. The largest discrepancies were found for large point sources and the on-road sector, suggesting that downscaled FFCO 2 data products could be improved by incorporating independent large point-source estimates and estimating on-road sources with a relevant spatial surrogate. Progressively coarsening the spatial resolution improves agreement but greater than approximately 25 km 2 , there were diminishing returns to agreement suggesting a practical resolution when using downscaled approaches.

Original languageEnglish (US)
Pages (from-to)2823-2840
Number of pages18
JournalJournal of Geophysical Research: Atmospheres
Volume124
Issue number5
DOIs
StatePublished - Mar 16 2019

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fossil fuels
Carbon Monoxide
Fossil fuels
urban areas
fossil fuel
urban area
data products
downscaling
roads
point sources
point source
estimates
road
carbon cycle
urban climate
bottom-up approach
infrastructure
labor
uncertainty
environmental policy

Keywords

  • bottom-up
  • downscaled
  • fossil fuel CO
  • mitigation
  • uncertainty
  • urban

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences (miscellaneous)
  • Palaeontology

Cite this

Comparison of Global Downscaled Versus Bottom-Up Fossil Fuel CO 2 Emissions at the Urban Scale in Four U.S. Urban Areas . / Gurney, Kevin; Liang, J.; O'Keeffe, D.; Patarasuk, R.; Hutchins, M.; Huang, J.; Rao, P.; Song, Y.

In: Journal of Geophysical Research: Atmospheres, Vol. 124, No. 5, 16.03.2019, p. 2823-2840.

Research output: Contribution to journalArticle

Gurney, Kevin ; Liang, J. ; O'Keeffe, D. ; Patarasuk, R. ; Hutchins, M. ; Huang, J. ; Rao, P. ; Song, Y. / Comparison of Global Downscaled Versus Bottom-Up Fossil Fuel CO 2 Emissions at the Urban Scale in Four U.S. Urban Areas In: Journal of Geophysical Research: Atmospheres. 2019 ; Vol. 124, No. 5. pp. 2823-2840.
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