Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 15, 7413-7427, 2015
http://www.atmos-chem-phys.net/15/7413/2015/
doi:10.5194/acp-15-7413-2015
© Author(s) 2015. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
09 Jul 2015
An ecosystem-scale perspective of the net land methanol flux: synthesis of micrometeorological flux measurements
G. Wohlfahrt1,2, C. Amelynck3, C. Ammann4, A. Arneth5, I. Bamberger5,6, A. H. Goldstein7, L. Gu8, A. Guenther9, A. Hansel10, B. Heinesch11, T. Holst12, L. Hörtnagl6, T. Karl13, Q. Laffineur14, A. Neftel4, K. McKinney15, J. W. Munger15, S. G. Pallardy16, G. W. Schade17, R. Seco18, and N. Schoon3 1Institute of Ecology, University of Innsbruck, Innsbruck, Austria
2European Academy of Bolzano, Bolzano, Italy
3Belgian Institute for Space Aeronomy, Brussels, Belgium
4Research Station Agroscope, Climate and Air Pollution Group, Zurich, Switzerland
5Karlsruhe Institute of Technology, IMK-IFU, Garmisch-Partenkirchen, Germany
6Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
7Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA
8Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
9Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, USA
10Institute of Ion Physics and Applied Physics, University of Innsbruck, Innsbruck, Austria
11Exchanges Ecosystems-Atmosphere, Department Biosystem Engineering (BIOSE), University of Liege, Gembloux, Belgium
12Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
13Institute of Meteorology and Geophysics, University of Innsbruck, Innsbruck, Austria
14Royal Meteorological Institute, Brussels, Belgium
15School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
16Department of Forestry, University of Missouri, Columbia, MO, USA
17Department of Atmospheric Sciences, Texas A&M University, College Station, TX, USA
18Department of Earth System Science, University of California, Irvine, CA 92697, USA
Abstract. 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.

Citation: Wohlfahrt, G., Amelynck, C., Ammann, C., Arneth, A., Bamberger, I., Goldstein, A. H., Gu, L., Guenther, A., Hansel, A., Heinesch, B., Holst, T., Hörtnagl, L., Karl, T., Laffineur, Q., Neftel, A., McKinney, K., Munger, J. W., Pallardy, S. G., Schade, G. W., Seco, R., and Schoon, N.: An ecosystem-scale perspective of the net land methanol flux: synthesis of micrometeorological flux measurements, Atmos. Chem. Phys., 15, 7413-7427, doi:10.5194/acp-15-7413-2015, 2015.
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Short summary
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 plants as the major source and the reaction with OH as the major sink, global methanol budgets diverge considerably in terms of source/sink estimates. Here we present micrometeorological methanol flux data from eight sites in order to provide a first cross-site synthesis of the terrestrial methanol exchange.
Methanol is the second most abundant volatile organic compound in the troposphere and plays a...
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