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The net ecosystem exchange of carbon dioxide was measured by eddy covariance methods for 3 years in two old-growth forest sites near Santarém, Brazil. Carbon was lost in the wet season and gained in the dry season, which was opposite to the seasonal cycles of both tree growth and model predictions. The 3-year average carbon loss was 1.3 (confidence(More)
The Orbiting Carbon Observatory (OCO) mission will make the first global, space-based measurements of atmospheric carbon dioxide (CO 2) with the precision, resolution, and coverage needed to characterize CO 2 sources and sinks on regional scales. The measurement approach and instrument specifications were determined through an analysis of existing carbon(More)
The eddy correlation method was used to measure the net ecosystem exchange of carbon dioxide continuously from April 1990 to December 1991 in a deciduous forest in central Massachusetts. The annual net uptake was 3.7 +/- 0.7 metric tons of carbon per hectare per year. Ecosystem respiration, calculated from the relation between nighttime exchange and soil(More)
[1] We analyzed 13 years (1992À2004) of CO 2 flux data, biometry, and meteorology from a mixed deciduous forest in central Massachusetts. Annual net uptake of CO 2 ranged from 1.0 to 4.7 Mg-C ha À1 yr À1 , with an average of 2.5 Mg-C ha À1 yr À1. Uptake rates increased systematically, nearly doubling over the period despite forest age of 75–110 years; there(More)
Net uptake of carbon dioxide (CO2) measured by eddy covariance in a 60- to 80-year-old forest averaged 2.0 +/- 0.4 megagrams of carbon per hectare per year during 1993 to 2000, with interannual variations exceeding 50%. Biometry indicated storage of 1.6 +/- 0.4 megagrams of carbon per hectare per year over 8 years, 60% in live biomass and the balance in(More)
The Moderate Resolution Imaging Radiometer (MODIS) is the primary instrument in the NASA Earth Observing System for monitoring the seasonality of global terrestrial vegetation. Estimates of 8-day mean daily gross primary production (GPP) at the 1 km spatial resolution are now operationally produced by the MODIS Land Science Team for the global terrestrial(More)
The role of carbon (C) and nitrogen (N) interactions on sequestration of atmospheric CO 2 in black spruce ecosystems across North America was evaluated with the Terrestrial Ecosystem Model (TEM) by applying para-meterizations of the model in which C–N dynamics were either coupled or uncoupled. First, the performance of the parameterizations, which were(More)
[1] We introduce a tool to determine surface fluxes from atmospheric concentration data in the midst of distributed sources or sinks over land, the Stochastic Time-Inverted Lagrangian Transport (STILT) model, and illustrate the use of the tool with CO 2 data over North America. Anthropogenic and biogenic emissions of trace gases at the surface cause large(More)
1 Measured surface-atmosphere fluxes of energy (sensible heat, H, and latent heat, 2 LE) and CO 2 (FCO 2) represent the " true " flux plus or minus potential random and 3 systematic measurement errors. Here we use data from seven sites in the AmeriFlux 4 network, including five forested sites (two of which include " tall tower " instrumentation), 5 one(More)