Four corners: The largest US methane anomaly viewed from space

Creators: Kort, Eric A.; Frankenberg, Christian; Costigan, Keeley R.; Lindenmaier, Rodica; Dubey, Manvendra K.; Wunch, Debra

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Abstract

Methane (CH_4) is a potent greenhouse gas and ozone precursor. Quantifying methane emissions is critical for projecting and mitigating changes to climate and air quality. Here we present CH_4 observations made from space combined with Earth‐based remote sensing column measurements. Results indicate the largest anomalous CH_4 levels viewable from space over the conterminous U.S. are located at the Four Corners region in the Southwest U.S. Emissions exceeding inventory estimates, totaling 0.59 Tg CH_4/yr [0.50–0.67; 2σ], are necessary to bring high‐resolution simulations and observations into agreement. This underestimated source approaches 10% of the EPA estimate of total U.S. CH4 emissions from natural gas. The persistence of this CH_4 signal from 2003 onward indicates that the source is likely from established gas, coal, and coalbed methane mining and processing. This work demonstrates that space‐based observations can identify anomalous CH_4 emission source regions and quantify their emissions with the use of a transport model.

Additional Information

© 2014. American Geophysical Union. Received 12 AUG 2014. Accepted 14 SEP 2014. Accepted article online 16 SEP 2014. Published online 9 OCT 2014. E.A.K. thanks the W. M. Keck Institute for Space Studies. Portions of this work were supported by NASA under award NNX14AI87G. Four Corners monitoring and modeling was supported by LANL's Laboratory Directed Research and Development Program (20110081DR, PI M.K.D.) with funds from DOE ASR, CCRD, and OSc to acquire and set up the LANL TCCON FTS. The Four Corners TCCON data were obtained from the TCCON Data Archive, operated by the California Institute of Technology from the website at http://tccon.ipac.caltech.edu/. Simulations were carried out on High Performance Computing resources under a grant from the LANL Institutional Computing Program. Portions of this work were conducted at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The authors thank Mike Gunson for comments on the manuscript. Geoffrey Tyndall thanks two anonymous reviewers for their assistance in evaluating this paper. This article also appears in: 2014 GRL Editor Highlights Hydraulic Fracturing