PIcntrl experiments

CCSM case names: b30.020.ES01 (years 0300-0429) b30.020.ES02 (years 0430-0799).


For the PIcntrl run, a version of the model was formulated including an interactive sulfur cycle which increased the model run time about 20%, and a branch was run from the PDcntrl run with GHGs and solar forcing instantaneously set to 1870 values. Sulfates were set to near zero. The model underwent an initial cooling, but after about 300 yr, the surface climate stabilized, with a net radiative imbalance of about 0.6 W m-2 at the top of atmosphere. This was associated with somewhat greater cooling in the deep ocean than in the PDcntrl run.
After the surface temperatures stabilized (i.e., long-term trend of 0.011 °C century-1), the PDcntrl run was continued for another 400 yr. The PIcntrl was used as the initial state for the 20C3M runs.

(Click on small images to see full-size plot)

Sulfate emissions Ozone concentration