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| Titel |
Implications of carbon monoxide bias for methane lifetime and atmospheric composition in chemistry climate models |
| VerfasserIn |
S. A. Strode, B. N. Duncan, E. A. Yegorova, J. Kouatchou, J. R. Ziemke, A. R. Douglass |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 20 ; Nr. 15, no. 20 (2015-10-23), S.11789-11805 |
| Datensatznummer |
250120117
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| Publikation (Nr.) |
 copernicus.org/acp-15-11789-2015.pdf |
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| Zusammenfassung |
| A low bias in carbon monoxide (CO) at northern high and mid-latitudes is a
common feature of chemistry climate models (CCMs) that may indicate or
contribute to a high bias in simulated OH and corresponding low bias in
methane lifetime. We use simulations with CO tagged by source type to
investigate the sensitivity of the CO bias to CO emissions, transport,
global mean OH, and the hemispheric asymmetry of OH. We also investigate how
each of these possible contributors to the CO bias affects the methane
lifetime. We find that the use of specified meteorology alters the
distribution of CO compared to a free-running CCM simulation, improving the
comparison with surface observations in summer. Our results also show that
reducing the hemispheric asymmetry of OH improves the agreement of simulated
CO with observations. We use simulations with parameterized OH to quantify
the impact of known model biases on simulated OH. Removing biases in ozone
and water vapor as well as reducing Northern Hemisphere NOx does not
remove the hemispheric asymmetry in OH, but it reduces global mean OH by
18 %, bringing the simulated methane lifetime into agreement with
observation-based estimates. |
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