Comparison of equilibrium and transient responses to CO2 increase in eight state-of-the-art climate models

Article English OPEN
Yokohata, Tokuta ; Emori, Seita ; Nozawa, Toru ; Ogura, Tomoo ; Kawamiya, Michio ; Tsushima, Yoko ; Suzuki, Tatsuo ; Yukimoto, Seiji ; Abe-Ouchi, Ayako ; Hasumi, Hiroyasu ; Sumi, Akimasa ; Kimoto, Masahide (2008)

We compared the climate response of doubled CO2 equilibrium experiments (2 × CO2) by atmosphere–slab ocean coupled general circulation models (ASGCMs) and that of 1% per year CO2 increase experiments (1%CO2 by atmosphere–ocean coupled general circulation models (AOGCMs) using eight state-of-the-art climate models. Climate feedback processes in 2 × CO2 are different from those in 1%CO2, and the equilibrium climate sensitivity (T2×) in 2 × CO2 is different from the effective climate sensitivity (T2×,eff) in 1%CO2. The difference between T2× and T2×,eff is from −1.3 to 1.6 K, a large part of which can be explained by the difference in the ice-albedo and cloud feedback. The largest contribution is cloud SW feedback, and the difference in cloud SW feedback for 2 × CO2 and 1%CO2 could be determined by the distribution of the SAT anomaly which causes differences in the atmospheric thermal structure. An important factor which determines the difference in ice-albedo feedback is the initial sea ice distribution at the Southern Ocean, which is generally overestimated in 2 × CO2 as compared to 1%CO2 and observation. Through the comparison of climate feedback processes in 2 ×CO2 and 1%CO2, the possible behaviour of the time evolution of T2×,eff is discussed.
  • References (53)
    53 references, page 1 of 6

    Boer, G. J. and Yu, B. 2003. Dynamical aspects of climate sensitivity. Geophys. Res. Lett. 30, 1135, doi:10.1029/2002GL016549.

    Bony, S. and Dufresne, J.-L. 2005. Marine boundary layer clouds at the heart of tropical cloud feedback uncertainties in climate models. Geophys. Res. Lett. 32, L20806, doi:10.1029/2005GL023851.

    Cess, R. D., Potter, G. L., Blanchet, J. P., Boer, G. L., Del Genio, A. D. and co-authors. 1990. Intercomparison and interpretation of climate feedback processes in 19 atmospheric general circulation models. J. Geophys. Res. 95, 16 601-16 615.

    Collins, W. D., Rasch, P. J., Boville, B. A., Hack, J. J., McCaa, J. R. and co-authors. 2004. Description of the NCAR Community Atmosphere Model (CAM3.0). Technical Note TN-464+STR, National Center for Atmospheric Research, Boulder, 214pp.

    Collins, W. D., Booth, B. B. B., Harris, G. R., Murphy, J. M., Sexton, D. M. H. and co-authors. 2006. Towards quantifying uncertainty in transient climate change. Clim. Dyn. 27, 127-147.

    Colman, R. A. 2003. A comparison of climate feedbacks in general circulation model. Clim. Dyn. 20, 865-873.

    Diansky, N. A., Bagno, A. V. and Zalensny, V. B. 2002. Sigma model of global ocean circulation and its sensitivity to variations in wind stress. Izv. Atmos. Ocean. Phys. 38, 477-494.

    Flato, G. M. 2005. The Third Generation Coupled Global Climate Model (CGCM3). http://www.cccma.bc.ec.gc.ca/models/cgcm3.shtml.

    Forster, P. M. D. and Taylor, K. E. 2006. Climate Forcings and climate sensitivities diagnosed from coupled climate model integrations. J. Clim. 19, 6181-6194.

    Galin, V. Ya, Volodin, E. M. and Smyshliaev, S. P. 2003. Atmospheric general circulation model of INM RAS with ozone dynamics. Russ. Meteorol. Hydrol. 5, 13-22.

  • Similar Research Results (1)
  • Metrics
    No metrics available
Share - Bookmark