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Trace gas exchange in a high‐Arctic valley: 2. Landscape CH 4 fluxes measured and modeled using eddy correlation data
Author(s) -
Friborg T.,
Christensen T. R.,
Hansen B. U.,
Nordstroem C.,
Soegaard H.
Publication year - 2000
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/1999gb001136
Subject(s) - environmental science , atmospheric sciences , trace gas , flux (metallurgy) , atmosphere (unit) , methane , arctic , eddy covariance , seasonality , climatology , chemistry , meteorology , geology , geography , oceanography , ecosystem , ecology , statistics , mathematics , organic chemistry , biology
Eddy correlation measurements of methane exchange were conducted during a period of 43 days covering the summer season in high‐arctic, NE Greenland. Measurements were carried out over a fen area and showed fluxes ranging from no exchange in the early part of the campaign to 120 mg m −2 d −1 during midsummer. The emission showed a clear variation related to soil temperatures and water table level in the late part of the summer, whereas the thickness of the active soil layer was a main controlling parameter in the thaw period, in the early part of the season. A model to assess methane emission dependency on physical parameters is found to give a realistic estimate for the seasonal variations in flux. The proportion of C returned to the atmosphere as CH 4 relative to the total C cycling was around 2%, which is similar to ratios often reported in literature. On the basis of these findings, an estimate is given for the total summer season emission of CH 4 , in which a simple model including both physical parameters and net primary production (NPP) is adapted to reproduce CH 4 exchange rates for periods when no measurements were undertaken. In this way the total emission of CH 4 during the period June 1 to September 1 1997, is found to equal 3.7 ± 0.57 g m −2 , which is a relatively high rate given the harsh climate in which the measurements were made.