title: Airborne methane remote measurements reveal heavy-tail flux distribution in Four Corners region.
abstract: Methane (CH4) impacts climate as the second strongest anthropogenic greenhouse gas and air quality by influencing tropospheric ozone levels. Space-based observations have identified the Four Corners region in the Southwest United States as an area of large CH4 enhancements. We conducted an airborne campaign in Four Corners during April 2015 with the next-generation Airborne Visible/Infrared Imaging Spectrometer (near-infrared) and Hyperspectral Thermal Emission Spectrometer (thermal infrared) imaging spectrometers to better understand the source of methane by measuring methane plumes at 1- to 3-m spatial resolution. Our analysis detected more than 250 individual methane plumes from fossil fuel harvesting, processing, and distributing infrastructures, spanning an emission range from the detection limit [Formula: see text] 2 kg/h to 5 kg/h through [Formula: see text] 5,000 kg/h. Observed sources include gas processing facilities, storage tanks, pipeline leaks, and well pads, as well as a coal mine venting shaft. Overall, plume enhancements and inferred fluxes follow a lognormal distribution, with the top 10% emitters contributing 49 to 66% to the inferred total point source flux of 0.23 Tg/y to 0.39 Tg/y. With the observed confirmation of a lognormal emission distribution, this airborne observing strategy and its ability to locate previously unknown point sources in real time provides an efficient and effective method to identify and mitigate major emissions contributors over a wide geographic area. With improved instrumentation, this capability scales to spaceborne applications [Thompson DR, et al. (2016) Geophys Res Lett 43(12):6571-6578]. Further illustration of this potential is demonstrated with two detected, confirmed, and repaired pipeline leaks during the campaign.
authors.affiliation: Division of Geology and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109; cfranken@caltech.edu.
authors.forename: Christian
authors.identifier: 0000-0002-0546-5857
authors.initials: C
authors.lastname: Frankenberg
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109;
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Thorpe
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109;
authors.forename: David R
authors.initials: DR
authors.lastname: Thompson
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109;
authors.forename: Glynn
authors.initials: G
authors.lastname: Hulley
authors.affiliation: Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI 48109;
authors.forename: Eric Adam
authors.initials: EA
authors.lastname: Kort
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109;
authors.forename: Nick
authors.initials: N
authors.lastname: Vance
authors.affiliation: Institute of Environmental Physics, University of Bremen, 28334 Bremen, Germany;
authors.forename: Jakob
authors.initials: J
authors.lastname: Borchardt
authors.affiliation: Institute of Environmental Physics, University of Bremen, 28334 Bremen, Germany;
authors.forename: Thomas
authors.initials: T
authors.lastname: Krings
authors.affiliation: Institute of Environmental Physics, University of Bremen, 28334 Bremen, Germany;
authors.forename: Konstantin
authors.initials: K
authors.lastname: Gerilowski
authors.affiliation: Cooperative Institute for Research in Environmental Sciences, University of Colorado-Boulder, Boulder, CO 80309; Global Monitoring Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305;
authors.forename: Colm
authors.initials: C
authors.lastname: Sweeney
authors.affiliation: Scientific Aviation, Boulder, CO 80301; Department of Land, Air, and Water Resources, University of California, Davis, CA 95616.
authors.forename: Stephen
authors.initials: S
authors.lastname: Conley
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109;
authors.forename: Brian D
authors.initials: BD
authors.lastname: Bue
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109;
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Aubrey
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109;
authors.forename: Simon
authors.initials: S
authors.lastname: Hook
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109;
authors.forename: Robert O
authors.initials: RO
authors.lastname: Green
keywords: Four Corners; heavy-tail; methane; remote sensing