The NCAR CCSM3-carbon is a coupled climate model that uses no flux correction (Collins et al., 2006a). The model components are the Community Atmosphere Model version 3 (CAM3; Collins et al. (2006b)), the Community Land Model version 3 (CLM3; Dickinson et al (2006)), the Parallel Ocean Program version 1.4 (POP1.4; Danabasoglu et al. (2006)), and the Community Sea Ice Model (CSIM; Holland et al. (2006)). The land model is on the same horizontal gird as CAM3 (T31) and the sea ice model shares the same horizontal grid as the ocean model (gx3v5). The CCSM3 ocean circulation model is a coarse resolution version of the parallel ocean program (POP) model with longitudinal resolution of 3.6 degrees and a variable latitudinal resolution from 1-2 degrees. There are 25 vertical levels with 8 levels in the upper 103 m.

The CCSM3 Biogeochemical Elemental Cycling (BEC) model includes several phytoplankton functional groups, one zooplankton group, semi-labile dissolved organic matter and sinking particulates (Moore et al., 2004). The BEC includes explicit cycling marine sediments, and the scavenging of iron onto particles balances the sources with 10% of scavenged iron presumed lost to the sediments (Moore and Braucher, 2008). Phytoplankton functional groups include diatoms, diazotrophs, picoplankton and coccolithophores. The export ratio is largely a function of phytoplankton community composition with diatom production being exported more efficiently than production by small phytoplankton. Phytoplankon growth rates and zooplankton grazing rates are modified by a temperature function that includes a Q10 factor of 2.0. Phytoplankton growth rates are also a function of nutrient and light limitation and these factors are multiplicative (Moore et al., 2004). Phytoplankton Fe/C, Chl/C, and si/C ratios adjuts dynamically to ambient nutrient and light, while the C/N/P ratios are fixed within each group (Moore et al., 2004).

In the simulations presented here both models were forced with prescribed CO2 emissions from reconstructions (1860--2000 AD) and a high emission scenario, SRES A2 (2000--2100 AD). Non-CO2 forching agents are also included.


Collins, W. D., C. M. Bitz, M. L. Blackmon, G. B. Bonan, C. S. Bretherton, J. A. Carton, P. Chang, S. C. Doney, J. J. Hack, T. B. Henderson, J. T. Kiehl, W. G. Large, D. S. McKennna, B. D. Santer, and R. D. Smith: The community climate system model version 3 (CCSM3), J. Climate, 19 (11), 2122-2143, doi: 10.11+5/JCLI3760.1, 2006a.

Collins, W. D., P. J. Rasch, B. A. Boville, J. J. Hack, J. R. McCaa, D. L. Williameson, and B. P. Briegleb: The formulation and atmospheric simulation of the community atmosphere model version 3 (CAM3), J. Climate, 19 (11), 2144-2161b, doi: 10.1175/JCLI3261.1, 2006b.

Danabasoglu, G., W. G. Large, J. J. Tribbia, P. R. Gent, B. P. Briegleb, and J. C. McWiliams: Diurnal coupling in the tropical oceans of CCSM3, J. Climate, 19 (11), 2302-2324, doi: 10.11+5/JCLI3742.1, 2006.

Dickinson, R. E, K. W. Oleson, G. Bonan, F. Hoffman, P. Thornton, M. Vertenstein, Z.-L. Yang, and X.Zeng: The community land model and its climate statistics as a component of the community climate system model, J. Climate 19 (11), 2302 - 2324, doi: 10.11+5/JCLI2742.1, 2006.

Holland, M. M., C. M. Bitz, E. C. Hunke, W. H. Lipscomb, and J. L. Schramm: Influence of the sea ice thickness distribution on polar climate in CCSM3, J. Climate, 19 (11), 2347 - 2365, doi: 10.117/JCLI3739.1, 2006.

Moore, J. K., Braucher, O.: Sedimentary and Mineral Dust Sources of Dissolved Iron to the World Ocean, Biogeosciences, 5, 631-656, 2008.

Moore, J. K., Doney, S. C., and Lindsay, K.: Upper ocean ecosystem dynamics and iron cycling in a global three-dimensional model, Global Biogeochem. Cy., 18, GB4028, doi: 10.1029/2004GB002220, 2004.