Details:

Journal Title:
Journal of Geophysical Research: Biogeosciences
Personal Author:
LaFranchi, B. W. ; McFarlane, K. J. ; Miller, J. B. ; Lehman, S. J. ; Phillips, C. L. ; ... More +
LaFranchi, B. W. ; McFarlane, K. J. ; Miller, J. B. ; Lehman, S. J. ; Phillips, C. L. ; Andrews, A. E. ; Tans, P. P. ; Chen, H. ; Liu, Z. ; Turnbull, J. C. ; Xu, X. ; Guilderson, T. P. Less -
NOAA Program & Office:
OAR (Oceanic and Atmospheric Research) ; ESRL (Earth System Research Laboratory) ; CIRES (Cooperative Institute for Research in Environmental Sciences) ; GML (Global Monitoring Laboratory)
OAR (Oceanic and Atmospheric Research) ; ESRL (Earth System Research Laboratory) ; CIRES (Cooperative Institute for Research in Environmental Sciences) ; GML (Global Monitoring Laboratory) Less -
Description:
Radiocarbon in CO2 ((CO2)-C-14) measurements can aid in discriminating between fast (< 1 year) and slower (> 5-10 years) cycling of C between the atmosphere and the terrestrial biosphere due to the 14C disequilibrium between atmospheric and terrestrial C. However, (CO2)-C-14 in the atmosphere is typically much more strongly impacted by fossil fuel emissions of CO2, and, thus, observations often provide little additional constraints on respiratory flux estimates at regional scales. Here we describe a data set of (CO2)-C-14 observations from a tall tower in northern Wisconsin (USA) where fossil fuel influence is far enough removed that during the summer months, the biospheric component of the (CO2)-C-14 budget dominates. We find that the terrestrial biosphere is responsible for a significant contribution to (CO2)-C-14 that is 2-3 times higher than predicted by the Carnegie-Ames-Stanford approach terrestrial ecosystem model for observations made in 2010. This likely includes a substantial contribution from the North American boreal ecoregion, but transported biospheric emissions from outside the model domain cannot be ruled out. The (CO2)-C-14 enhancement also appears somewhat decreased in observations made over subsequent years, suggesting that 2010 may be anomalous. With these caveats acknowledged, we discuss the implications of the observation/ model comparison in terms of possible systematic biases in the model versus short-term anomalies in the observations. Going forward, this isotopic signal could be exploited as an important indicator to better constrain both the long-term carbon balance of terrestrial ecosystems and the short-term impact of disturbance-based loss of carbon to the atmosphere.
Source:
Journal of Geophysical Research-Biogeosciences, 121(8), 2275-2295.
DOI:
http://dx.doi.org/10.1002/2015jg003271
Document Type:
Journal Article
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Submitted
Main Document Checksum:
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urn:sha256:577fa4df8d6a12600e23f9704da13982616639d4e6c56386d1d2c40e11a648d5
Download URL:
https://repository.library.noaa.gov/view/noaa/18309/noaa_18309_DS1.pdf
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