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| Titel |
An ecosystem-scale perspective of the net land methanol flux: synthesis of micrometeorological flux measurements |
| VerfasserIn |
G. Wohlfahrt, C. Amelynck, C. Ammann, A. Arneth, I. Bamberger, A. H. Goldstein, L. Gu, A. Guenther, A. Hansel, B. Heinesch, T. Holst, L. Hörtnagl, T. Karl, Q. Laffineur, A. Neftel, K. McKinney, J. W. Munger, S. G. Pallardy, G. W. Schade, R. Seco, N. Schoon |
| 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. 13 ; Nr. 15, no. 13 (2015-07-09), S.7413-7427 |
| Datensatznummer |
250119878
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| Publikation (Nr.) |
 copernicus.org/acp-15-7413-2015.pdf |
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| Zusammenfassung |
| Methanol is the second most abundant volatile organic compound in the
troposphere and plays a significant role in atmospheric chemistry. While
there is consensus about the dominant role of living plants as the major
source and the reaction with OH as the major sink of methanol, global
methanol budgets diverge considerably in terms of source/sink estimates,
reflecting uncertainties in the approaches used to model and the empirical
data used to separately constrain these terms. Here we compiled
micrometeorological methanol flux data from eight different study sites and
reviewed the corresponding literature in order to provide a first cross-site
synthesis of the terrestrial ecosystem-scale methanol exchange and present
an independent data-driven view of the land–atmosphere methanol exchange.
Our study shows that the controls of plant growth on production, and
thus the methanol emission magnitude, as well as stomatal conductance on the hourly
methanol emission variability, established at the leaf level, hold across
sites at the ecosystem level. Unequivocal evidence for bi-directional
methanol exchange at the ecosystem scale is presented. Deposition, which at
some sites even exceeds methanol emissions, represents an emerging feature
of ecosystem-scale measurements and is likely related to environmental
factors favouring the formation of surface wetness. Methanol may adsorb to
or dissolve in this surface water and eventually be chemically or
biologically removed from it. Management activities in agriculture and
forestry are shown to increase local methanol emission by orders of
magnitude; however, they are neglected at present in global budgets. While
contemporary net land methanol budgets are overall consistent with the grand
mean of the micrometeorological methanol flux measurements, we caution that
the present approach of simulating methanol emission and deposition
separately is prone to opposing systematic errors and does not allow for full advantage to be taken of the rich information content of micrometeorological flux
measurements. |
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