Wienhold, F.G.Welling, M.Harris, G.W.2010-06-112010-06-111995Atmos. Environ., 29, 2219-2227.http://hdl.handle.net/10315/4195Nitrous oxide (N2O) fluxes were measured by eddy correlation during a field experiment in August 1993. The measurements took place on a harvested wheat field located in northwest Sealand (Denmark). A. tunable diode laser absorption spectrometer (TDLAS) was used for N2O detection. The N2O mixing ratio was sampled at a rate of 10 Hz synchronously with the three-dimensional wind data, air temperature, water vapour and carbon dioxide (CO2) concentrations. Fast Fourier transform methods were applied to analyse spectral and co-spectral power distributions and to compute the fluxes from the covariance functions. Balance of the energy budget indicated adequate frequency coverage of the flux contributions. Continuous measurements were carried out in half hour intervals during daytime and fluxes in the range of 40–120 ng N m−2 s−1 were obtained. The footprint regions for the individual measurements were estimated by Markovian trajectory simulations taking into account the atmospheric stability conditions and wind distributions inferred from the micrometeorological measurements. The influence of adjoining fields with different crops was evident in the Bowen ratio and CO2 flux, but not noticeable in the N2O flux. This observation is consistent with supporting analysis of the soil depth dependence of the nitrous oxide production, which indicates that the major contributions arise from levels below 0.9 m.enFlux measurementseddy correlationtunable diode laser spectroscopyfootprint analysisMarkovian trajectory simulationArticlehttp://www.elsevier.com/wps/find/homepage.cws_home