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AGU: Geophysical Research Letters

 

Index Terms

  • Biogeosciences: Biogeophysics
  • Biogeosciences: Biosphere/atmosphere interactions
  • Biogeosciences: Climate dynamics
  • Atmospheric Processes: Paleoclimatology
  • Paleoceanography: Global climate models

Abstract

Vegetation dynamics amplifies precessional forcing

Martin Claussen

Meteorological Institute, University Hamburg and Max Planck Institute for Meteorology, Hamburg, Germany

Jens Fohlmeister

Heidelberg Academy of Sciences, Heidelberg, Germany

Andrey Ganopolski

Potsdam Institute for Climate Impact Research, Potsdam, Germany

Victor Brovkin

Potsdam Institute for Climate Impact Research, Potsdam, Germany

The astronomical theory of climate variations predicts that the climatic precession which changes the seasonal distance between Earth and Sun does not affect the annual mean irradiation at any given latitude. However, previous modeling studies suggest that during interglacials, the interaction between atmosphere, vegetation and ocean can transform the seasonal forcing by precession into an annual mean global signal. Here, we show that this result can be generalized. A distinct precessional signal emerges in a climate system model over many precessional cycles. While neither the atmosphere-ocean nor the atmosphere-vegetation model are able to produce a large amplitude of global temperature in the precessional band, only the mutual amplification of biogeophysical feedback and sea ice- albedo feedback allows a strong amplification of the precessional signal.

Received 2 March 2006; accepted 3 April 2006; published 12 May 2006.

Citation: Claussen, M., J. Fohlmeister, A. Ganopolski, and V. Brovkin (2006), Vegetation dynamics amplifies precessional forcing, Geophys. Res. Lett., 33, L09709, doi:10.1029/2006GL026111.

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