Hourly observations of forest-atmosphere energy balance components are presented for the Morgan-Monroe State Forest, south-central Indiana, USA for the period March 1998 to December 2001, with particular emphasis on the storage heat flux (ΔQS). The sub-components of ΔQS showed strong diurnal variability, although ground heat flux dominated the seasonal change of storage heat flux. The… More

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The role of mid-latitude forests in the sequestration of carbon (C) is of interest to an increasing number of scientists and policy-makers alike. Net CO2 exchange can be estimated on an annual basis, using eddy-covariance techniques or from ecological inventories of C fluxes to and from a forest. Here we present an intercomparison of annual… More

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We tested the hypothesis that the date of the onset of net carbon uptake by temperate deciduous forest canopies corresponds with the time when the mean daily soil temperature equals the mean annual air temperature. The hypothesis was tested using over 30 site-years of data from 12 field sites where CO2 exchange is being measured… More

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Quantifying net carbon (C) storage by forests is a necessary step in the validation of carbon sequestration estimates and in assessing the possible role of these ecosystems in offsetting fossil fuel emissions. In eastern North America, five sites were established in deciduous forests to provide measurements of net ecosystem CO2 exchange (NEE) using micro-meteorological methods,… More

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Results from the first full year of measurements (1998–1999) of above canopy CO2 and energy fluxes at the AmeriFlux site in the Morgan-Monroe State Forest, IN, USA, are presented. The site is located in an extensive secondary successional broadleaf forest in the maple-beech to oak-hickory transition zone. The minimum fetch is 4 km. Turbulent flux measurements… More

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This paper presents observations of ammonia, nitric acid and size segregated chemically speciated aerosols above the canopy of a secondary successional deciduous forest in Indiana during spring. Average nitric acid concentrations range between 0.1–1 µg m−3 and vertical gradients from 1 to 9 ng m−3 / m. The ammonia probability distribution indicates an average concentration… More

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A physiologically-driven spectral index using two ocean-color bands of MODIS satellite sensor showed great potential to track seasonally changing photosynthetic light use efficiency (LUE) and stress-induced reduction in net primary productivity (NPP) of terrestrial vegetation. Based on these findings, we developed a simple “continuous field” model solely based on remotely sensed spectral data that could… More

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Observations of net ecosystem exchange (NEE) of carbon and its biophysical drivers have been collected at the AmeriFlux site in the Morgan-Monroe State Forest (MMSF) in Indiana, USA since 1998. Thus, this is one of the few deciduous forest sites in the world, where a decadal analysis on net ecosystem productivity (NEP) trends is possible…. More

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Ecosystem models often perform poorly in reproducing interannual variability in carbon and water fluxes, resulting in considerable uncertainty when estimating the land-carbon sink. While many aggregated variables (growing season length, seasonal precipitation, or temperature) have been suggested as predictors for interannual variability in carbon fluxes, their explanatory power is limited and uncertainties remain as to… More

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Ecosystem models often perform poorly in reproducing interannual variability in carbon and water fluxes, resulting in considerable uncertainty when estimating the land-carbon sink. While many aggregated variables (growing season length, seasonal precipitation, or temperature) have been suggested as predictors for interannual variability in carbon fluxes, their explanatory power is limited and uncertainties remain as to… More

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