نتایج جستجو برای: eddy covariance

تعداد نتایج: 44832  

2011
Marina Molodovskaya Brian K. Richards Tammo S. Steenhuis

Eddy covariance and static chambers are different-scale methods for monitoring agricultural N2O that, when used together on heterogeneous agricultural landscapes, can help identify flux sources and sinks and evaluate the effect of management interventions on landscape-scale N2O emissions. This study compared the N2O flux data obtained by eddy covariance and static chambers during a short-term N...

2017
Jinshu Chi Fidel Maureira Sarah Waldo Shelley N. Pressley Claudio O. Stöckle Patrick T. O'Keeffe William L. Pan Erin S. Brooks Dave R. Huggins Brian K. Lamb

Citation: Chi J, Maureira F, Waldo S, Pressley SN, Stöckle CO, O’Keeffe PT, Pan WL, Brooks ES, Huggins DR and Lamb BK (2017) Carbon and Water Budgets in Multiple Wheat-Based Cropping Systems in the Inland Pacific Northwest US: Comparison of CropSyst Simulations with Eddy Covariance Measurements. Front. Ecol. Evol. 5:50. doi: 10.3389/fevo.2017.00050 Carbon and Water Budgets in Multiple Wheat-Bas...

2012
Georg Wohlfahrt Katja Klumpp Jean-François Soussana

In this chapter we first provide a historic overview of – and outline some of the peculiarities associated with – grassland eddy covariance flux measurements, elaborate on the additional terms that need to be quantified when estimating the grassland net ecosystem carbon balance and finally discuss some of the challenges associated with upcoming nitrous oxide and methane flux measurements in man...

2007
M. D. Mahecha M. Reichstein H. Lange N. Carvalhais C. Bernhofer T. Grünwald D. Papale G. Seufert

Characterizing ecosystem-atmosphere interactions from short to interannual time scales M. D. Mahecha, M. Reichstein, H. Lange, N. Carvalhais, C. Bernhofer, T. Grünwald, D. Papale, and G. Seufert Max-Planck-Institute for Biogeochemistry, Jena, Germany Norwegian Forest and Landscape Institute, Ås, Norway Environmental System Analysis Group, New University of Lisbon, Portugal Deptartment of Meteor...

2006
T. Foken

After briefly discussing several reasons for the energy balance closure problem in the surface layer, the paper focuses on the influence of the low frequency part of the turbulence spectrum on the residual. Changes in the turbulent fluxes in this part of the turbulence spectrum were found to have a significant influence on the changes of the residual. Using the ogive method, it was found that t...

Journal: :Hydrological Research Letters 2011

Journal: :Global change biology 2015
Heather N Speckman John M Frank John B Bradford Brianna L Miles William J Massman William J Parton Michael G Ryan

Eddy covariance nighttime fluxes are uncertain due to potential measurement biases. Many studies report eddy covariance nighttime flux lower than flux from extrapolated chamber measurements, despite corrections for low turbulence. We compared eddy covariance and chamber estimates of ecosystem respiration at the GLEES Ameriflux site over seven growing seasons under high turbulence [summer night ...

Journal: :Journal of Geophysical Research: Atmospheres 1998

2013
Kell B. Wilson Tilden Meyers KELL B. WILSON TILDEN P. MEYERS

Fluxes of carbon dioxide, water and sensible heat were measured using three different eddy covariance systems above the forest floor of a closed deciduous forest (leaf area index ≈ 6). The primary objective was to examine the representativeness of a single eddy covariance system in estimating soil respiration for time scales ranging from one-half hour to more than one week. Experiments were con...

2007
D. M. D. Hendriks A. J. Dolman

A Fast Methane Analyzer (FMA) is assessed for its applicability in a closed path eddy covariance field set-up in a peat meadow. The FMA uses off-axis integrated cavity output spectroscopy combined with a highly specific narrow band laser for the detection of CH4 and strongly reflective mirrors to obtain a laser path length of 2–20×103 m. Statistical testing and a calibration experiment showed h...

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