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 SRES A2 experiment. 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. SRA2: SRES A2) - 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_SRA2_1_G_hur850 This model run continues from the end of the 20th century simulation with GHG and aerosol loadings for the IPCC SRES A2 scenario as tabulated in the IPCC Third Assessment Report, Appendix II. The CO2 concentrations are from the Bern-CC model (Contribution of Working Group I to the Third Assesment Report of IPCC, p808) and the aerosol loadings are from O. Boucher, Laboratoire d'Optique Atmospherique, France. For this experiment there are 5 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/.