Biogeosciences www.biogeosciences.net 1726-4170 1726-4189 6 2 2009 10.5194/bg-6-285-2009 http://www.biogeosciences.net/6/285/2009/ http://www.biogeosciences.net/6/285/2009/bg-6-285-2009.html http://www.biogeosciences.net/6/285/2009/bg-6-285-2009.pdf 285 295 2009-02-25 The interannual variability of Africa's ecosystem productivity: a multi-model analysis U. Weber uweber@bgc-jena.mpg.de M. Jung M. Reichstein C. Beer M. C. Braakhekke V. Lehsten D. Ghent J. Kaduk N. Viovy P. Ciais N. Gobron C. Rödenbeck Department of Forest Science and Environment,University of Tuscia, Viterbo, Italy Max Planck Institute for Biogeochemistry, Jena, Germany GeoBiosphere Science Centre, Lund University, Sweden Department of Geography, University of Leicester, UK Laboratoire des Sciences du Climate et de l' Environnement, Gif-sur-Yvette, France European Commission – DG Joint Research Centre, Institute for Environment and Sustainability, Global Environment Monitoring Unit, Ispra (VA), Italy We are comparing spatially explicit process-model based estimates of the terrestrial carbon balance and its components over Africa and confront them with remote sensing based proxies of vegetation productivity and atmospheric inversions of land-atmosphere net carbon exchange. Particular emphasis is on characterizing the patterns of interannual variability of carbon fluxes and analyzing the factors and processes responsible for it. For this purpose simulations with the terrestrial biosphere models ORCHIDEE, LPJ-DGVM, LPJ-Guess and JULES have been performed using a standardized modeling protocol and a uniform set of corrected climate forcing data. <br><br> While the models differ concerning the absolute magnitude of carbon fluxes, we find several robust patterns of interannual variability among the models. Models exhibit largest interannual variability in southern and eastern Africa, regions which are primarily covered by herbaceous vegetation. Interannual variability of the net carbon balance appears to be more strongly influenced by gross primary production than by ecosystem respiration. A principal component analysis indicates that moisture is the main driving factor of interannual gross primary production variability for those regions. On the contrary in a large part of the inner tropics radiation appears to be limiting in two models. 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