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1. Introduction Closing the energy budget at flux measurement sites is problematic, with up to 30% of energy unaccounted for even when the fetch ideally extends over flat, homogeneous surfaces with low vegetation cover Failure to close the energy balance at a particular site may imply that some or all of the scalar fluxes have been inaccurately measured(More)
To determine the role of grazing on CO 2 fluxes in a desert steppe, we used paired eddy-covariance systems to measure the net ecosystem exchange (NEE) and microclimate on adjacent pastures of grazed (GS) and ungrazed (FS) steppes on the Mongolian Plateau from 2010 to 2011. The first year was an average precipitation year, while the second year was a dry(More)
Quantifying regional evapotranspiration (ET) and environmental constraints are particularly important for understanding water and carbon cycles of terrestrial ecosystems. However, a large uncertainty in the regional estimation of ET still remains for the terrestrial ecosystems in China. This study used ET measurements of 34 eddy covariance sites within(More)
We investigated the variability of soil respiration and several potential regulatory factors and modeled their interrelationships from May to August over a 5-year period in oak forests subjected to alternative harvesting treatments as part of the Missouri Ozark Forest Ecosystem Project (MOFEP). Treatments included even-aged management (EAM), uneven-aged(More)
Our knowledge about the variability of the net ecosystem exchange (NEE) of CO 2 in terrestrial ecosystems at multiple time scales remains poor; yet, it is critical to global modeling analyses for quantifying the terrestrial carbon cycle (Stoy et al., 2009). NEE is simultaneously modulated by multiple physical and biological forcing factors that constantly(More)
Introduction: Low energy balance closure (EBC) at a particular eddy-covariance flux site has increased the uncertainties of carbon, water, and energy measurements and has thus hampered the urgent research of scaling up and modeling analyses through site combinations in regional or global flux networks. Methods: A series of manipulative experiments were(More)
Freshwater marshes are well-known for their ecological functions in carbon sequestration, but complete carbon budgets that include both methane (CH4 ) and lateral carbon fluxes for these ecosystems are rarely available. To the best of our knowledge, this is the first full carbon balance for a freshwater marsh where vertical gaseous [carbon dioxide (CO2 )(More)
This study was designed to estimate the canopy biophysical characteristics of semi-arid grassland ecosystems by using in situ field spectrometry measurements to identify important spectral information for predictions at broader spatial scales. Spectral vegetation indices (VIs), reflectance spectra, continuum removal spectra, and the amplitude of the red(More)
BACKGROUND Mowing is a widely adopted management practice for the semiarid steppe in China and affects CH(4) exchange. However, the magnitude and the underlying mechanisms for CH(4) uptake in response to mowing remain uncertain. METHODOLOGY/PRINCIPAL FINDINGS In two consecutive growing seasons, we measured the effect of mowing on CH(4) uptake in a steppe(More)
The regression tree method is used to upscale evapotranspiration (ET) measurements at eddy-covariance (EC) towers to the grassland ecosystems over the Dryland East Asia (DEA). The regression tree model was driven by satellite and meteorology datasets, and explained 82% and 76% of the variations of ET observations in the calibration and validation datasets,(More)