Studying the spatial variability of methane flux with five eddy covariance towers of varying height

摘要: In this study, the spatial representativeness of eddy covariance (EC) methane (CH4) measurements was examined by comparing parallel CH4 fluxes from three short (6 m) towers separated a few kilometres and two higher levels (20 m 60 at one location. The measurement campaign held on an intensively managed grassland peat soil in Netherlands. land use cover types are to large degree homogeneous area. exhibited significant variability between sites 30-min scale. coefficient variation (CVspa) 56% it similar magnitude as temporal variability, unlike for other (friction velocity, sensible heat flux) which considerably larger than variability. CVspa decreased with averaging, although less what could be expected purely random process (1/root N), 14% 26-day means flux. This reflects underlying heterogeneity flux studied landscape scales ranging 1 ha (flux footprint) 10 km(2) (area bounded towers). should taken into account when interpreting EC measurements. On annual scale, contributed up 50% uncertainty emissions. It further tested whether used acquire more accurate estimate spatially integrated Contrarily expected, intensity found both increase decrease depending height. Using footprint modelling, 6 attributed emissions local anthropogenic hotspots (farms). Furthermore, morning hours proved demanding tall tower where were four-fold those lower heights. These differences connected onset convective mixing during period. (C) 2015 Authors. Published Elsevier B.V.