Abstract / Description of output
Flux gradient, eddy covariance and relaxed eddy accumulation methods were applied to measure CH$_{4}$ and N$_{2}$O emissions from peatlands and arable land respectively. Measurements of N$_{2}$O emission by eddy covariance using tunable diode laser spectroscopy provided fluxes ranging from 2 to 60 $\mu $mol N$_{2}$O m$^{-2}$ h$^{-1}$ with a mean value of 22 $\mu $mol N$_{2}$O m$^{-2}$ h$^{-1}$ from 320 h of continuous measurements. Fluxes of CH$_{4}$ measured above peatland in Caithness (U.K.) during May and June 1993 by eddy covariance and relaxed eddy accumulation methods were in the range 70 to 120 $\mu $mol CH$_{4}$ m$^{-2}$ h$^{-1}$ with means of 14.7 $\mu $mol CH$_{4}$ m$^{-2}$ h$^{-1}$ and 22.7 $\mu $mol CH$_{4}$ m$^{-2}$ h$^{-1}$ respectively. Emissions of CH$_{4}$ from peatland changed with water table depth and soil temperature; increasing from 25 $\mu$mol CH$_{4}$ m$^{-2}$ h$^{-1}$ at 5% pool area to 50 $\mu $mol CH$_{4}$ m$^{-2}$ h$^{-1}$ with 30% within the flux footprint occupied by pools. A temperature response of 4.9 $\mu $mol CH$_{4}$ m$^{-2}$ h$^{-1}$ degrees C$^{-1}$ in the range 6-12 degrees C was also observed. The close similarity in average CH$_{4}$ emission fluxes reported for wetlands in Caithness, Hudson Bay and Alaska in the range 11 to 40 $\mu $mol CH$_{4}$ m$^{-2}$ h$^{-1}$ suggests that earlier estimates of CH$_{4}$ emission from high latitude wetlands were too large or that the area of high latitudes contributing to CH$_{4}$ emission has been seriously underestimated.
Original language | English |
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Pages (from-to) | 339-355 |
Number of pages | 17 |
Journal | Philosophical Transactions A: Mathematical, Physical and Engineering Sciences |
Volume | 351 |
Issue number | 1696 |
DOIs | |
Publication status | Published - May 1995 |