Case studies for initialized decadal hindcasts and predictions for the Pacific region

Case studies involving notable past decadal climate variability are analyzed for the mid-1970s climate shift, when the tropical Pacific warmed over a decade and globally averaged temperature rapidly increased, and the early 2000s hiatus when the tropical Pacific cooled over a decade and global temperatures warmed little. Ten year hindcasts following the CMIP5 decadal climate prediction experiment design are analyzed for those two periods using two different initialization techniques in a global coupled climate model, the CCSM4.

There is additional skill in the initialized hindcasts for surface temperature patterns over the Pacific region for those two case studies over and above that in free-running historical simulations with the same model. A 30 year hindcast also shows added skill over the Pacific compared to the historical simulations. A 30 year prediction from the initialized model simulations shows less global warming for the 2016-2035 period than the free-running model projection for that same time period.