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GEOPHYSICAL RESEARCH LETTERS,
VOL. 34,
L09703,
doi:10.1029/2006GL029019,
2007
Impact of terrestrial biosphere carbon exchanges on the anomalous CO2 increase in 2002–2003
W. Knorr
Quantifying and Understanding the Earth System Research (QUEST), Department of Earth Sciences, University of Bristol, Bristol,
UK
N. Gobron
Institute for Environment and Sustainability, European Commission Joint Research Centre, Ispra, Italy
M. Scholze
Quantifying and Understanding the Earth System Research (QUEST), Department of Earth Sciences, University of Bristol, Bristol,
UK
T. Kaminski
FastOpt, Hamburg, Germany
R. Schnur
Max-Planck-Institute for Meteorology, Hamburg, Germany
B. Pinty
Institute for Environment and Sustainability, European Commission Joint Research Centre, Ispra, Italy
Abstract
Understanding the carbon dynamics of the terrestrial biosphere during climate fluctuations is a prerequisite for any reliable
modeling of the climate-carbon cycle feedback. We drive a terrestrial vegetation model with observed climate data to show
that most of the fluctuations in atmospheric CO2 are consistent with the modeled shift in the balance between carbon uptake by terrestrial plants and carbon loss through
soil and plant respiration. Simulated anomalies of the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) during
the last two El Niño events also agree well with satellite observations. Our model results suggest that changes in net primary
productivity (NPP) are mainly responsible for the observed anomalies in the atmospheric CO2 growth rate. Changes in heterotrophic respiration (Rh) mostly happen in the same direction, but with smaller amplitude. We attribute the unusual acceleration of the atmospheric
CO2 growth rate during 2002–2003 to a coincidence of moderate El Niño conditions in the tropics with a strong NPP decrease at
northern mid latitudes, only partially compensated by decreased Rh.
Received 6
December
2006;
accepted 3
April
2007;
published 5
May
2007.
Keywords: carbon cycle;
climate change;
terrestrial biosphere.
Index Terms: 1615 Global Change: Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 4805, 4912); 3305 Atmospheric Processes: Climate change and variability (1616, 1635, 3309, 4215, 4513); 3360 Atmospheric Processes: Remote sensing.
Read Full Article (file size: 543927 bytes) Cited by
Citation: Knorr, W., N. Gobron, M. Scholze, T. Kaminski, R. Schnur, and B. Pinty
(2007),
Impact of terrestrial biosphere carbon exchanges on the anomalous CO2 increase in 2002–2003,
Geophys. Res. Lett.,
34,
L09703,
doi:10.1029/2006GL029019.
Copyright 2007 by the American Geophysical Union.
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