Ankur R. Desai

Learn More
The Moderate Resolution Spectroradiometer (MODIS) sensor has provided near real-time estimates of gross primary production (GPP) since March 2000. We compare four years (2000 to 2003) of satellite-based calculations of GPP with tower eddy CO2 flux-based estimates across diverse land cover types and climate regimes. We examine the potential error(More)
[1] Disturbances are important for renewal of North American forests. Here we summarize more than 180 site years of eddy covariance measurements of carbon dioxide flux made at forest chronosequences in North America. The disturbances included stand‐ replacing fire (Alaska, Arizona, Manitoba, and Saskatchewan) and harvest (British Columbia, Florida, New(More)
We review 15 techniques for estimating missing values of net ecosystem CO2 exchange (NEE) in eddy covariance time series and evaluate their performance for different artificial gap scenarios based on a set of 10 benchmark datasets from six forested sites in Europe. The goal of gap filling is the reproduction of the NEE time series and hence this present(More)
Turbulent fluxes of carbon, water vapor, and temperature were continuously measured above an upland forest in north central Wisconsin during 1999 and 2000 using the eddy covariance method. Maple (Acer saccharum), basswood (Tilia americana), and green ash (Fraxinus pennsylvanica) species found in this forest also comprise a substantial portion of the(More)
Kevin Schaefer, Christopher R. Schwalm, Chris Williams, M. Altaf Arain, Alan Barr, Jing M. Chen, Kenneth J. Davis, Dimitre Dimitrov, Timothy W. Hilton, David Y. Hollinger, Elyn Humphreys, Benjamin Poulter, Brett M. Raczka, Andrew D. Richardson, Alok Sahoo, Peter Thornton, Rodrigo Vargas, Hans Verbeeck, Ryan Anderson, Ian Baker, T. Andrew Black, Paul(More)
a College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China b U.S. Geological Survey (USGS), Earth Resources Observation and Science (EROS) Center, Sioux Falls, South Dakota 57198, USA c Geographic Information Science Center of Excellence, South Dakota State University, Brookings, South Dakota 57007, USA d(More)
[1] Ecosystem CO2 exchange and atmosphere boundary layer (ABL) mixing are correlated diurnally and seasonally as they are both driven by solar insulation. Tracer transport models predict that these covariance signals produce a meridional gradient of annual mean CO2 concentration in the marine boundary layer that is half as strong as the signal produced by(More)
Understanding the relationships between climate and carbon exchange by terrestrial ecosystems is critical to predict future levels of atmospheric carbon dioxide because of the potential accelerating effects of positive climate–carbon cycle feedbacks. However, directly observed relationships between climate and terrestrial CO2 exchange with the atmosphere(More)
Ecosystem respiration (ER) was measured with the eddy covariance technique in 14 forest ecosystems in the Upper Great Lakes Region during the growing seasons of 2002 and 2003. The response of ER to soil temperature and moisture was analyzed using empirical models. On average, ER was higher in the intermediate and young than in the mature stands, and higher(More)
Eddy covariance flux towers measure net exchange of land–atmosphere flux. For the flux of carbon dioxide, this net ecosystem exchange (NEE) is governed by two processes, gross primary production (GPP) and a sum of autotrophic and heterotrophic respiration components known as ecosystem respiration (RE). A number of statistical flux-partitioning methods,(More)