TY - JOUR
T1 - Toward quantification and source sector identification of fossil fuel CO2 emissions from an urban area
T2 - Results from the INFLUX experiment
AU - Turnbull, Jocelyn C.
AU - Sweeney, Colm
AU - Karion, Anna
AU - Newberger, Timothy
AU - Lehman, Scott J.
AU - Tans, Pieter P.
AU - Davis, Kenneth J.
AU - Lauvaux, Thomas
AU - Miles, Natasha L.
AU - Richardson, Scott J.
AU - Cambaliza, Maria Obiminda
AU - Shepson, Paul B.
AU - Gurney, Kevin
AU - Patarasuk, Risa
AU - Razlivanov, Igor
N1 - Funding Information:
This research was generously funded by the National Institute of Standards and Technology (grant 60NANB10D023) and the National Oceanic and Atmospheric Administration Climate Program Office’s AC4 program (award NA13OAR4310074). The measurements and analysis presented here would not be possible without the extensive support from the NOAA/ESRL Global Monitoring Division, special thanks to Pat Lang, Kelly Sours, Jonathan Kofler, and Arlyn Andrews. Radiocarbon measurements were made at University of Colorado INSTAAR/University of California Irvine and at GNS Science, thanks to John Southon, John B. Miller, Chad Wolak, Patrick Cappa, Stephen Morgan,Jenny Dahl,Kelly Lyons, Margaret Norris, Johannes Kaiser, and Albert Zondervan. LEF 14CO2 data are used courtesy of Brian LaFranchi, Karis McFarlane, and Thomas Guilderson at the Lawrence Livermore National Laboratory. Flask sample collection logistics and maintenance are provided by Earth Networks, Inc. Data used in this paper are available from the INFLUX website [http://sites.psu.edu/influx/] either as direct download from the INFLUX website or raw flask measurement data accessed from the NOAA/ESRL database for which download access is described on the INFLUX website. A password is required before data can be accessed in either format; directions for obtaining a password can be found on the website. Thank you to three reviewers for their insights and helpful suggestions that have improved this paper.
Publisher Copyright:
© 2014. American Geophysical Union. All Rights Reserved.
PY - 2015/1/16
Y1 - 2015/1/16
N2 - The Indianapolis Flux Experiment (INFLUX) aims to develop and assess methods for quantifying urban greenhouse gas emissions. Here we use CO2, 14CO2, and CO measurements from tall towers around Indianapolis, USA, to determine urban total CO2, the fossil fuel derived CO2 component (CO2ff), and CO enhancements relative to background measurements. When a local background directly upwind of the urban area is used, the wintertime total CO2enhancement over Indianapolis can be entirely explained by urban CO2ff emissions. Conversely, when a continental background is used, CO2ff enhancements are larger and account for only half the total CO2enhancement, effectively representing the combined CO2ff enhancement from Indianapolis and the wider region. In summer, we find that diurnal variability in both background CO2 mole fraction and covarying vertical mixing makes it difficult to use a simple upwind-downwind difference for a reliable determination of total CO2urban enhancement. We use characteristic CO2ff source sector CO:CO2ff emission ratios to examine the contribution of the CO2ff source sectors to total CO2ff emissions. This method is strongly sensitive to the mobile sector, which produces most CO. We show that the inventory-based emission product (“bottom up”) and atmospheric observations (“top down”) can be directly compared throughout the diurnal cycle using this ratio method. For Indianapolis, the top-down observations are consistent with the bottom-up Hestia data product emission sector patterns for most of the diurnal cycle but disagree during the nighttime hours. Further examination of both the top-down and bottom-up assumptions is needed to assess the exact cause of the discrepancy.
AB - The Indianapolis Flux Experiment (INFLUX) aims to develop and assess methods for quantifying urban greenhouse gas emissions. Here we use CO2, 14CO2, and CO measurements from tall towers around Indianapolis, USA, to determine urban total CO2, the fossil fuel derived CO2 component (CO2ff), and CO enhancements relative to background measurements. When a local background directly upwind of the urban area is used, the wintertime total CO2enhancement over Indianapolis can be entirely explained by urban CO2ff emissions. Conversely, when a continental background is used, CO2ff enhancements are larger and account for only half the total CO2enhancement, effectively representing the combined CO2ff enhancement from Indianapolis and the wider region. In summer, we find that diurnal variability in both background CO2 mole fraction and covarying vertical mixing makes it difficult to use a simple upwind-downwind difference for a reliable determination of total CO2urban enhancement. We use characteristic CO2ff source sector CO:CO2ff emission ratios to examine the contribution of the CO2ff source sectors to total CO2ff emissions. This method is strongly sensitive to the mobile sector, which produces most CO. We show that the inventory-based emission product (“bottom up”) and atmospheric observations (“top down”) can be directly compared throughout the diurnal cycle using this ratio method. For Indianapolis, the top-down observations are consistent with the bottom-up Hestia data product emission sector patterns for most of the diurnal cycle but disagree during the nighttime hours. Further examination of both the top-down and bottom-up assumptions is needed to assess the exact cause of the discrepancy.
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U2 - 10.1002/2014JD022555
DO - 10.1002/2014JD022555
M3 - Article
AN - SCOPUS:84922017801
SN - 0148-0227
VL - 120
SP - 292
EP - 312
JO - Journal of Geophysical Research
JF - Journal of Geophysical Research
IS - 1
ER -