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. The dataset names are composed of - centre/model acronym (e.g. MPEH5: Max-Planck-Institute/Echam5) - scenario acronym (e.g. PICTL: PICNTRL) - run number (e.g. 1: run 1) - format identifier (e.g. N: netCDF, G: GRIB) - variable acronym [with level value] (e.g. hur850: relative humidity, 850 hPa) --> example: MPEH5_PICTL_1_G_hur850 Separate realisation of control experiment with CSIRO Mk 3.0 model, starting from model year 120 of PIcntrl and continuing oversame interval as 1%to2x experiment, and with radiative forcings held same as PIcntrl. Atmospheric fields retained on the full model grid. For this experiment there are 2 ensemble runs available. For model output data in higher temporal resulution and more variables visit the web page https://esg.llnl.gov:8443/home/publicHomePage.do.