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| Titel |
The influence of biogenic emissions on upper-tropospheric methanol as revealed from space |
| VerfasserIn |
G. Dufour, S. Szopa, D. A. Hauglustaine, C. D. Boone, C. P. Rinsland, P. F. Bernath |
| 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 ; 7, no. 24 ; Nr. 7, no. 24 (2007-12-13), S.6119-6129 |
| Datensatznummer |
250005278
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| Publikation (Nr.) |
 copernicus.org/acp-7-6119-2007.pdf |
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| Zusammenfassung |
| The distribution and budget of oxygenated organic compounds in the
atmosphere and their impact on tropospheric chemistry are still poorly
constrained. Near-global space-borne measurements of seasonally resolved
upper tropospheric profiles of methanol (CH3OH) by the ACE Fourier transform
spectrometer provide a unique opportunity to evaluate our understanding of
this important oxygenated organic species. ACE-FTS observations from March 2004 to
August 2005 period are presented. These observations reveal the pervasive imprint
of surface sources on upper tropospheric methanol: mixing ratios observed in the
mid and high latitudes of the Northern Hemisphere reflect the seasonal cycle of
the biogenic emissions whereas the methanol cycle observed in the southern tropics
is highly influenced by biomass burning emissions. The comparison with distributions
simulated by the state-of-the-art global chemistry transport model, LMDz-INCA,
suggests that: (i) the background methanol (high southern latitudes) is correctly
represented by the model considering the measurement uncertainties; (ii) the
current emissions from the continental biosphere are underestimated during spring
and summer in the Northern Hemisphere leading to an underestimation of modelled
upper tropospheric methanol; (iii) the seasonal variation of upper tropospheric
methanol is shifted to the fall in the model suggesting either an insufficient
destruction of CH3OH (due to too weak chemistry and/or deposition) in fall
and winter months or an unfaithful representation of transport; (iv) the impact
of tropical biomass burning emissions on upper tropospheric methanol is rather
well reproduced by the model. This study illustrates the potential of these first
global profile observations of oxygenated compounds in the upper troposphere to
improve our understanding of their global distribution, fate and budget. |
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