Understanding changes in the burden and growth rate of atmospheric methane (CH4) has been the focus of several recent studies but still lacks scientific consensus. Here we investigate the role of decreasing anthropogenic carbon monoxide (CO) emissions since 2002 on hydroxyl radical (OH) sinks and tropospheric CH4 loss. We quantify this impact by contrasting two model simulations for 2002-2013: (1) a Measurement of the Pollution in the Troposphere (MOPITT) CO reanalysis and (2) a Control-Run without CO assimilation. These simulations are performed with the Community Atmosphere Model with Chemistry of the Community Earth System Model fully coupled chemistry climate model with prescribed CH4 surface concentrations. The assimilation of MOPITT observations constrains the global CO burden, which significantly decreased over this period by similar to 20%. We find that this decrease results to (a) increase in CO chemical production, (b) higher CH4 oxidation by OH, and (c) similar to 8% shorter CH4 lifetime. We elucidate this coupling by a surrogate mechanism for CO-OH-CH4 that is quantified from the full chemistry simulations.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/626068 |
| Date | 16 October 2017 |
| Creators | Gaubert, B., Worden, H. M., Arellano, A. F. J., Emmons, L. K., Tilmes, S., Barré, J., Martinez Alonso, S., Vitt, F., Anderson, J. L., Alkemade, F., Houweling, S., Edwards, D. P. |
| Contributors | Univ Arizona, Dept Hydrol & Atmospher Sci, Atmospheric Chemistry Observations and Modeling Laboratory; National Center for Atmospheric Research; Boulder CO USA, Atmospheric Chemistry Observations and Modeling Laboratory; National Center for Atmospheric Research; Boulder CO USA, Department of Hydrology and Atmospheric Sciences; University of Arizona; Tucson AZ USA, Atmospheric Chemistry Observations and Modeling Laboratory; National Center for Atmospheric Research; Boulder CO USA, Atmospheric Chemistry Observations and Modeling Laboratory; National Center for Atmospheric Research; Boulder CO USA, Atmospheric Chemistry Observations and Modeling Laboratory; National Center for Atmospheric Research; Boulder CO USA, Atmospheric Chemistry Observations and Modeling Laboratory; National Center for Atmospheric Research; Boulder CO USA, Atmospheric Chemistry Observations and Modeling Laboratory; National Center for Atmospheric Research; Boulder CO USA, Institute for Mathematics Applied to Geosciences; National Center for Atmospheric Research; Boulder CO USA, SRON Netherlands Institute for Space Research; Utrecht Netherlands, SRON Netherlands Institute for Space Research; Utrecht Netherlands, Atmospheric Chemistry Observations and Modeling Laboratory; National Center for Atmospheric Research; Boulder CO USA |
| Publisher | AMER GEOPHYSICAL UNION |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Article |
| Rights | ©2017. American Geophysical Union. All Rights Reserved. |
| Relation | http://doi.wiley.com/10.1002/2017GL074987 |
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