Observational constraints on recent increases in the atmospheric CHâ burden
Measurements of atmospheric CHâ from air samples collected weekly at 46 remote surface sites show that, after a decade of near-zero growth, globally averaged atmospheric methane increased during 2007 and 2008. During 2007, CHâ increased by 8.3 ± 0.6 ppb. CHâ mole fractions averaged over polar northern latitudes and the Southern Hemisphere increased more than other zonally averaged regions. In 2008, globally averaged CHâ increased by 4.4 ± 0.6 ppb; the largest increase was in the tropics, while polar northern latitudes did not increase. Satellite and in situ CO observations suggest only a minor contribution to increased CH4 from biomass burning. The most likely drivers of the CHâ anomalies observed during 2007 and 2008 are anomalously high temperatures in the Arctic and greater than average precipitation in the tropics. Near-zero CHâ growth in the Arctic during 2008 suggests we have not yet activated strong climate feedbacks from permafrost and CHâ hydrates.
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https://n2t.org/ark:/85065/d7ms3trk
eng
geoscientificInformation
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publication
2016-01-01T00:00:00Z
publication
2009-09-17T00:00:00Z
An edited version of this paper was published by AGU. Copyright 2009 American Geophysical Union.
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