Releases of the greenhouse gases carbon dioxide (CO2) and methane (CH4) from thawing permafrost are expected to be among the largest feedbacks to climate from arctic ecosystems. However, the current net carbon (C) balance of terrestrial arctic ecosystems is unknown. Recent studies suggest that these ecosystems are sources, sinks, or approximately in balance at present…. More

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Aerodynamic canopy height (ha) is the effective height of vegetation canopy for its influence on atmospheric fluxes and is a key parameter of surface‐atmosphere coupling. However, methods to estimate ha from data are limited. This synthesis evaluates the applicability and robustness of the calculation of ha from eddy covariance momentum‐flux data. At 69 forest sites,… More

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The exchanges of carbon dioxide (CO2), water vapor, and energy were measured nearly continuously since 1996 over a mixed mature transition forest at the Borden Forest Research Station, in southern Ontario, Canada. Borden Forest, one of the longest running flux towers in North America, is located in the temperate–boreal ecotone. This transitional region, which includes… More

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Results of an experiment conducted to quantify the ozone deposition onto a deciduous forest stand in an acid-precipitation-impacted area of Canada are presented and discussed. The ozone deposition data were obtained above and within the forest canopy. The deposition process was affected by solar radiation, wind speed and ambient ozone concentration. Solar radiation was likely… More

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Measurements of isoprene concentration and flux were made at a mixed deciduous forest in southern Canada during 1995 to characterize diel and seasonal emissions and thus deduce annual inventories. Isoprene inventories are necessary for inputs to modeling systems to study atmospheric chemistry and carbon budgets. Despite adequate environmental conditions to promote emissions, the onset of… More

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