A technique for estimating surface albedo feedback (SAF) from standard monthly mean climate model diagnostics is applied to the 1%/year CO2 increase transient climate change integrations of twelve IPCC AR4 climate models. Over the 80 year runs, the models produce a mean SAF at the surface of 0.3 W/m2/K with a standard deviation of 0.09 W/m2/K. Compared to 2xCO2 equilibrium run estimates from an earlier group of models, both the mean SAF and the standard deviation are reduced. Three quarters of the model mean SAF comes from the northern hemisphere in roughly equal parts from the land and ocean areas. The remainder is due to southern hemisphere ocean areas. The SAF differences between the models are shown to stem mainly from the sensitivity of the surface albedo to surface temperature rather than from the impact of a given surface albedo change on the shortwave budget.

Full Article: http://www.gfdl.noaa.gov/~mw/ar4_paper.pdf

Last Updated: 2006-03-01