CCSM case names: b30.009
For the PDcntrl run, first the atmosphere was tuned to near zero (less than 0.1 W m-2) net energy balance at the top of atmosphere using the same land mask as the coupled model and observed SSTs. The ocean was initialized with Levitus observations, whereas the sea ice and land surface conditions were initialized from a previous run with observed forcing. The components were then coupled and run for an initial 100-yr spin-up adjustment period where sea ice in the first few decades increased, then decreased, and became nearly stable after about 100 yr. At this time there was a small (about 0.2 W m-2) net radiative imbalance at the top of atmosphere associated with a gradual cooling of the deep ocean. The model was then run for 400 yr. The 1% yr-1 compound CO2 increase runs (1pct_to2x and 1pct_to4x) were branched from this simulation.
(Click on small images to see full-size plot)