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Showing papers in "Agricultural and Forest Meteorology in 2002"



Journal ArticleDOI
TL;DR: The authors compared seasonal and annual estimates of CO2 and water vapor exchange across sites in forests, grasslands, crops, and tundra that are part of an international network called FLUXNET, and investigated the responses of vegetation to environmental variables.

1,199 citations


Journal ArticleDOI
TL;DR: In this article, the effects of disturbance history, climate, and changes in atmospheric carbon dioxide (CO2) concentration and nitrogen deposition (Ndep) on carbon and water fluxes in seven North American evergreen forests are assessed using a coupled water-carbon-nitrogen model, canopy-scale flux observations, and descriptions of the vegetation type, management practices, and disturbance histories at each site.

821 citations


Journal ArticleDOI
TL;DR: In this paper, the authors reviewed several recently expressed concerns about uncertainties of chamber-based measurements of CO2 emissions from soils, and explained procedures that minimize these errors and biases, and provided procedures to minimize these uncertainties and biases.

730 citations


Journal ArticleDOI
TL;DR: In this paper, seasonal patterns of gross primary productivity (FGPP), and ecosystem respiration (FRE) of boreal and temperate, deciduous and coniferous forests, Mediterranean evergreen systems, a rainforest, temperate grasslands, and C3 and C4 crops were analyzed.

655 citations


Journal ArticleDOI
TL;DR: In this article, the authors extend the discussions of a US DOE sponsored workshop held on 30 and 31 May, 2000 in Boulder, CO concerning issues and uncertainties related to long-term eddy covariance measurements of carbon and energy exchanges.

639 citations


Journal ArticleDOI
TL;DR: Reducing soil evaporation could be one of the most important water-saving measures in this serious water deficit region.

532 citations


Journal ArticleDOI
TL;DR: The footprint of a turbulent flux measurement defines its spatial context as mentioned in this paper, and the footprint is used to define the spatial context of a flux measurement, as well as its utility and power where warranted.

497 citations


Journal ArticleDOI
TL;DR: In this article, the authors present a cross-site synthesis of annual carbon storage estimates, comparing meteorological and biometric approaches, and also comparing biometric estimates based on analyses of autotrophic carbon pools and heterotropic carbon fluxes (net ecosystem production, NEP).

400 citations


Journal ArticleDOI
TL;DR: In this paper, the eddy covariance technique was used to measure evapotranspiration and sensible heat flux continuously for 2.5 years (three growing seasons) in a northern grassland near Lethbridge, Alta., Canada.

303 citations


Journal ArticleDOI
TL;DR: In this article, a regression analysis of data from mature forests produced the following relationship: annual soil respiration = 287 + 2.80 × annual litterfall, which further implies that TBCA is roughly twice annual aboveground litterfall-C.

Journal ArticleDOI
TL;DR: In this paper, CO2 exchange was measured on the forest floor of a coastal temperate Douglas-fir forest located near Campbell River, British Columbia, Canada, using an automated chamber system between April and December, 2000.

Journal ArticleDOI
TL;DR: In this article, a set of agrometeorological parameters, derived from the classic climate parameters, that are capable of indicating the consequences of climate change for crop production are defined.

Journal ArticleDOI
TL;DR: An eddy covariance measurement system was installed to measure long-term turbulent fluxes of heat, water vapor, and CO2 over a cool-temperate deciduous forest in the central part of Japan as mentioned in this paper.

Journal ArticleDOI
TL;DR: The view that the widespread reductions in potential evaporation that have been reported, although not found at Bet Dagan, were caused by global dimming rather than an increase in the rate of atmospheric moisture cycling due to global warming is supported.

Journal ArticleDOI
TL;DR: In this paper, the authors measured the energy budget of a subalpine coniferous forest over two complete annual cycles and found that the energy balance was slightly better in the winter as opposed to summer, since numerous periods of high turbulence occur in winter.

Journal ArticleDOI
TL;DR: In this article, the authors describe measurements of net ecosystem exchange (NEE) over a temperate coniferous forest in The Netherlands and show no loss of night-time fluxes at low values of friction velocity.

Journal ArticleDOI
TL;DR: In this paper, seasonal patterns of net ecosystem carbon exchange (FNEE) using eddy covariance data of the FLUXNET data base ( http://www-eosdis.ornl.gov/FLUXNET ).

Journal ArticleDOI
TL;DR: For 212 days, including a 117-day-long summer drought with only 45mm rainfall, fluxes of latent and sensible heat (λE and H, respectively) and carbon dioxide (CO2) were measured by eddy covariance over a tussock grassland in New Zealand as discussed by the authors.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the variability in transpiration and conductance between individual trees of Scots pine and Norway spruce in a mixed 50-year-old stand in central Sweden.

Journal ArticleDOI
TL;DR: In this paper, the carbon dioxide and water vapor exchange were measured over a young and an old-growth ponderosa pine (Pinus ponderosaDougl. ex P. & C. Laws) ecosystem located in a semiarid environment in central Oregon.

Journal ArticleDOI
TL;DR: In this paper, the authors present a review of the theory, computer modelling and practices relating to light transmission, apart from an interesting, but unproven new design to improve transmission.

Journal ArticleDOI
TL;DR: An automated transient-state closed-system canopy-chamber for gas-exchange determinations of field-crops was developed to allow unattended day and night, high frequency CO 2 and H 2 O exchange measurements, with short measurement time (15 s) and high scanning rate (0.5 s) as discussed by the authors.

Journal ArticleDOI
TL;DR: In this article, the authors measured net atmospheric exchanges of energy and water vapor using eddy covariance along a chronosequence ofPinus elliottii plantations in north Florida: a recent clearcut, a mid-rotation stand, and a 24-year-old, rotation-aged stand.

Journal ArticleDOI
TL;DR: In this article, the authors investigate how canopy openness and light transmission are affected by selection cutting, and how they vary over time following harvesting in northern hardwood stands in Quebec (Canada), where they sampled five sugar maple-yellow birch-beech (Acer saccharum-Betula alleghaniensis-Fagus grandifolia) stands.

Journal ArticleDOI
TL;DR: In this paper, paired digital and film hemispherical photographs were taken in conifer plantations in southern and central Scotland, with a wide range of light environments, and the analysis package Hemiview was used to calculate canopy openness, diffuse and direct transmittance, and leaf area index.

Journal ArticleDOI
TL;DR: In this article, a modelling study on intercropping was carried out to understand the radiation interception and use, and the radiation transmission models on both instantaneous and daily bases were described and validated.

Journal ArticleDOI
TL;DR: In this paper, the authors used the turbulent Schmidt number (Sc) to calculate the tracer emission rate and found that Sc averaged 0.6, with large variability between observation periods, with no obvious correlation to atmospheric conditions.


Journal ArticleDOI
TL;DR: In this paper, the authors used the growing degree days method, which assumes the daily temperature varies as a sine wave, to calculate the mean heat accumulation for predicting the Quercus pollination start in different climatic areas.