Nguyen, Newton H. and Turner, Alexander J. and Yin, Yi and Prather, Michael J. and Frankenberg, Christian (2020) Effects of Chemical Feedbacks on Decadal Methane Emissions Estimates. Geophysical Research Letters, 47 (3). Art. No. e2019GL085706. ISSN 0094-8276. doi:10.1029/2019gl085706. https://resolver.caltech.edu/CaltechAUTHORS:20200122-145933294
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Abstract
The coupled chemistry of methane, carbon monoxide (CO), and hydroxyl radical (OH) can modulate methane's 9‐year lifetime. This is often ignored in methane flux inversions, and the impacts of neglecting interactive chemistry have not been quantified. Using a coupled‐chemistry box model, we show that neglecting the effect of methane source perturbation on [OH] can lead to a 25% bias in estimating abrupt changes in methane sources after only 10 years. Further, large CO emissions, such as from biomass burning, can increase methane concentrations by extending the methane lifetime through impacts on [OH]. Finally, we quantify the biases of including (or excluding) coupled chemistry in the context of recent methane and CO trends. Decreasing CO concentrations, beginning in the 2000's, have notable impacts on methane flux inversions. Given these nonnegligible errors, decadal methane emissions inversions should incorporate chemical feedbacks for more robust methane trend analyses and source attributions.
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Additional Information: | © 2020 American Geophysical Union. Received 7 OCT 2019; Accepted 15 JAN 2020; Accepted article online 16 JAN 2020. This work was supported by a NSF Graduate Research Fellowship (to N. H. Nguyen) and a grant from the Grantham Foundation (to Y. Yin and N. H. Nguyen). A. J. Turner is supported as a Miller Fellow with the Miller Institute for Basic Research in Science at UC Berkeley. The authors declare no conflict of interest. The two‐hemisphere box model can be accessed via Github https://github.com/Newton-Climate/Methane_OH_box; surface observations were accessed from the following sources: CH urn:x-wiley:grl:media:grl60131:grl60131-math-0128 NOAA (ftp://aftp.cmdl.noaa.gov/data/trace_gases/ch4/flask/); MCF NOAA (ftp://aftp.cmdl.noaa.gov/data/hats/solvents/CH3CCl3/); MCF GAGE/AGAGE (http://agage.mit.edu/); and CO NOAA (ftp://aftp.cmdl.noaa.gov/data/trace_gases/co/flask/surface/). | ||||||||||||
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Issue or Number: | 3 | ||||||||||||
DOI: | 10.1029/2019gl085706 | ||||||||||||
Record Number: | CaltechAUTHORS:20200122-145933294 | ||||||||||||
Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20200122-145933294 | ||||||||||||
Official Citation: | Nguyen, N. H., Turner, A. J., Yin, Y., Prather, M. J., & Frankenberg, C. (2020). Effects of chemical feedbacks on decadal methane emissions estimates. Geophysical Research Letters, 47, e2019GL085706. https://doi.org/10.1029/2019GL085706 | ||||||||||||
Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | ||||||||||||
ID Code: | 100855 | ||||||||||||
Collection: | CaltechAUTHORS | ||||||||||||
Deposited By: | Tony Diaz | ||||||||||||
Deposited On: | 22 Jan 2020 23:09 | ||||||||||||
Last Modified: | 16 Nov 2021 17:57 |
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