Climate Dynamics

, Volume 32, Issue 7, pp 901–923

Multiple temporal scale variability during the twentieth century in global carbon dynamics simulated by a coupled climate–terrestrial carbon cycle model

Article

DOI: 10.1007/s00382-009-0548-1

Cite this article as:
Kato, T., Ito, A. & Kawamiya, M. Clim Dyn (2009) 32: 901. doi:10.1007/s00382-009-0548-1

Abstract

A coupled climate–carbon cycle model composed of a process-based terrestrial carbon cycle model, Sim-CYCLE, and the CCSR/NIES/FRCGC atmospheric general circulation model was developed. We examined the multiple temporal scale functions of terrestrial ecosystem carbon dynamics induced by human activities and natural processes and evaluated their contribution to fluctuations in the global carbon budget during the twentieth century. Global annual net primary production (NPP) and heterotrophic respiration (HR) increased gradually by 6.7 and 4.7%, respectively, from the 1900s to the 1990s. The difference between NPP and HR was the net carbon uptake by natural ecosystems, which was 0.6 Pg C year−1 in the 1980s, whereas the carbon emission induced by human land-use changes was 0.5 Pg C year−1, largely offsetting the natural terrestrial carbon sequestration. Our results indicate that monthly to interannual variation in atmospheric CO2 growth rate anomalies show 2- and 6-month time lags behind anomalies in temperature and the NiNO3 index, respectively. The simulated anomaly amplitude in monthly net carbon flux from terrestrial ecosystems to the atmosphere was much larger than in the prescribed air-to-sea carbon flux. Fluctuations in the global atmospheric CO2 time series were dominated by the activity of terrestrial vegetation. These results suggest that terrestrial ecosystems have acted as a net neutral reservoir for atmospheric CO2 concentrations during the twentieth century on an interdecadal timescale, but as the dominant driver for atmospheric CO2 fluctuations on a monthly to interannual timescale.

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Tomomichi Kato
    • 1
    • 2
    • 3
  • Akihiko Ito
    • 1
    • 4
  • Michio Kawamiya
    • 1
  1. 1.Frontier Research Center for Global ChangeJapan Agency for Marine-Earth Science and TechnologyYokohamaJapan
  2. 2.QUEST, Department of Earth SciencesUniversity of BristolBristolUK
  3. 3.Japan Society for the Promotion of Science, Postdoctoral Fellow for Research AbroadTokyoJapan
  4. 4.National Institute for Environmental StudiesTsukubaJapan

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