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On the role of trend and variability in the hydroxyl radical (OH) in the global methane budget

Zhao, Yuanhong; Saunois, Marielle; Bousquet, Philippe; Lin, Xin; Berchet, Antoine; Hegglin, Michaela I.; Canadell, Josep G.; Jackson, Robert B.; Deushi, Makoto; Jöckel, Patrick; Kinnison, Douglas; Kirner, Ole; Strode, Sarah; Tilmes, Simone; Dlugokencky, Edward J.; Zheng, Bo

Decadal trends and interannual variations in the hydroxyl radical (OH), while poorly constrained at present, are critical for understanding the observed evolution of atmospheric methane (CH$_4$). Through analyzing the OH fields simulated by the model ensemble of the Chemistry–Climate Model Initiative (CCMI), we find (1) the negative OH anomalies during the El Niño years mainly corresponding to the enhanced carbon monoxide (CO) emissions from biomass burning and (2) a positive OH trend during 1980–2010 dominated by the elevated primary production and the reduced loss of OH due to decreasing CO after 2000. Both two-box model inversions and variational 4D inversions suggest that ignoring the negative anomaly of OH during the El Niño years leads to a large overestimation of the increase in global CH$_4$ emissions by up to 10 ± 3 Tg yr$^{−1}$ to match the observed CH$_4$ increase over these years. Not accounting for the increasing OH trends given by the CCMI models leads to an underestimation of the CH$_4$ emission increase by 23 ± 9 Tg yr$^{−1}$ from 1986 to 2010. The variational-inversion-estimated CH$_4$ emissions show that the tropical regions contribute most to the uncertainties related to OH. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000125992
Veröffentlicht am 12.11.2020
DOI: 10.5194/acp-20-13011-2020
Cover der Publikation
Zugehörige Institution(en) am KIT Steinbuch Centre for Computing (SCC)
Publikationstyp Zeitschriftenaufsatz
Publikationsdatum 06.11.2020
Sprache Englisch
Identifikator ISSN: 1680-7324
KITopen-ID: 1000125992
HGF-Programm 46.11.01 (POF III, LK 01) Computational Science and Mathematical Methods
Erschienen in Atmospheric chemistry and physics
Band 20
Heft 21
Seiten 13011–13022
Schlagwörter climate change atmospheric chemistry methane greenhouse gases
Nachgewiesen in Scopus
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