@article{ef65e94b9e304939a606b8ab0e11e9ee,
title = "Assessing fossil fuel CO2 emissions in California using atmospheric observations and models",
abstract = "Analysis systems incorporating atmospheric observations could provide a powerful tool for validating fossil fuel CO2 (ffCO2) emissions reported for individual regions, provided that fossil fuel sources can be separated from other CO2 sources or sinks and atmospheric transport can be accurately accounted for. We quantified ffCO2 by measuring radiocarbon (14C) in CO2, an accurate fossil-carbon tracer, at nine observation sites in California for three months in 2014-15. There is strong agreement between the measurements and ffCO2 simulated using a high-resolution atmospheric model and a spatiotemporally-resolved fossil fuel flux estimate. Inverse estimates of total in-state ffCO2 emissions are consistent with the California Air Resources Board's reported ffCO2 emissions, providing tentative validation of California's reported ffCO2 emissions in 2014-15. Continuing this prototype analysis system could provide critical independent evaluation of reported ffCO2 emissions and emissions reductions in California, and the system could be expanded to other, more data-poor regions.",
keywords = "California, atmospheric inversion, carbon dioxide, fossil fuel emissions, radiocarbon",
author = "H. Graven and Fischer, {M. L.} and T. Lueker and S. Jeong and Guilderson, {T. P.} and Keeling, {R. F.} and R. Bambha and K. Brophy and W. Callahan and X. Cui and C. Frankenberg and Gurney, {K. R.} and Lafranchi, {B. W.} and Lehman, {S. J.} and H. Michelsen and Miller, {J. B.} and S. Newman and W. Paplawsky and Parazoo, {N. C.} and C. Sloop and Walker, {S. J.}",
note = "Funding Information: This project was funded by NASA Carbon Monitoring System (NNX13AP33G and NNH13AW56I). Work at LBNL was conducted under US Department of Energy Contract No. DE-AC02-5CH11231. Work at LLNL was conducted under the auspices of the US Department of Energy contract DE-AC52-07NA27344. Measurements at WGC were supported by NOAA. H G acknowledges support from the European Commission through a Marie Curie Career Integration Grant. W Callahan and C Sloop are employed by Earth Networks, Inc., a commercial company that provides environmental monitoring services. S Afshar, R Dickau, S Rider, R Robles and T Walpert assisted with flask sampling. The California Air Resources Board provided access to the Sutter Buttes sampling site. G Turi provided CO2 fluxes from the ROMS model, S R Kawa provided CO2 fluxes from CASA-GFED3, and E Acu{\~n}a-Yeomans assisted with nuclear power plant data. The authors acknowledge helpful discussions with T Arnold, E Campbell, B Croes, Y Hsu, L Iraci, J Kim, A Manning, M Whelan and D Wunch. Publisher Copyright: {\textcopyright} 2018 The Author(s). Published by IOP Publishing Ltd.",
year = "2018",
month = jun,
doi = "10.1088/1748-9326/aabd43",
language = "English (US)",
volume = "13",
journal = "Environmental Research Letters",
issn = "1748-9326",
publisher = "IOP Publishing Ltd.",
number = "6",
}