These data represent monthly averaged values of selected variables for the Data Distribution Centre(DDC) of the Intergovernmental Panel on Climate Change (IPCC). (see also http://www.ipcc-data.org/) The model output prepared for IPCC Fourth Assessment climate of the Pre-industrial control experiment (picntrl). _ These datasets are available in netCDF and GRIB format. _ This simulation was initiated from year 280 of CCSM3 model run b30.017 and executed on hardware bluesky.ucar.edu. _ Physical constants used for derived data: Lv (latent heat of evaporation): 2.501e6 J kg-1 Lf (latent heat of fusion ): 3.337e5 J kg-1 r[h2o] (density of water ): 1000 kg m-3 g2kg (grams to kilograms ): 1000 g kg-1 _ Integrations were performed by NCAR and CRIEPI with support and facilities provided by NSF, DOE, MEXT and ESC/JAMSTEC. _ For this experiment there are 2 ensemble runs available. _ Model output data for CMIP3 in higher temporal resolutions and further variables are available in ESGF at https://esgf-node.llnl.gov/search/cmip3/.