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Title:
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Modelling of carbon isotope discrimination by vegetation
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Author(s):
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Hidy, D.; Haszpra, L.; Barcza, Z.; Vermeulen, A.T.; Tuba, Z.; Nagy, Z.
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Published by:
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Publication date:
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ECN
Biomass, Coal and Environmental Research
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20-11-2009
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ECN report number:
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Document type:
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ECN-W--09-037
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Article (scientific)
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Number of pages:
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15
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Published in: Photosynthetica (), , , Vol., p.-.
Abstract:
The paper presents a simple box model simulating the temporal variation of atmospheric 13CO2 concentration, atmospheric CO2 mixing ratio and 13C content of plant material. The model is driven by observed meteorological and measured biosphere-atmosphere CO2 exchange data. The model was calibrated and validated using measurements from a Hungarian atmospheric monitoring station. The simulated atmospheric stable carbon isotope ratio data agreed well with the measured ratios considering both the magnitude and the seasonal dynamics. Observed deviations between the measured and simulated d13Cair values were systematically negative in winters, while deviations were random in sign and smaller by an order of magnitude during periods when the vegetation was photosynthetically active. This difference, supported by a significant correlation between the deviation and modeled fossil fuel contributions to CO2 concentration, suggests the increased contribution of 13C-depleted fossil fuel CO2 from heating and the lower boundary layer heights during winter.
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