These data represent monthly mean values of selected variables for ENSEMBLES (http://www.ensembles-eu.org). The list of output variables can be found in: http://ensembles.wdc-climate.de/output-variables The model output was prepared for the ENSEMBLES Stream 2 experiment. The model was initialised from the HadGEM2-AO 20C3M run 1 using 1999 conditions. Anthropogenic forcings (only) were changed through the run to follow values representing the SRES A1B scenario from the IPCC Fourth Assessment, i.e changes in: CO2, CH4, N2O, CFC11, CFC12, CFC113, HCFC22, Ozone, Vegetation Distribution, Sulphur-cycle Emissions, Soot Emissions, Biomass Emissions. No variations were made to solar radiation and volcanic aerosols. Most of the forcings were identical to the equivalent HadGEM1 A1B run with the exception of the vegetation distribution which was modified to reflect the commonly-agreed method for including forcing from anthropogenic land use change in ENSEMBLES Stream 2 simulations, in this case using Nathalie de Noblet's maps of future crop and pasture extent derived from the IMAGE2.2 model projections of crop/pasture land use change in the 21st century under A1B. These datasets are available in netCDF format. The dataset names are composed of - centre/model acronym (e.g. METO-HC_HadGEM2AO, for acronym:HADGEM2) - scenario acronym (e.g. SRA1B: SRES A1B) - run number (e.g. 1: run 1) - time interval (MM:monthly mean, DM:daily mean, D0:daily instantaneous at 0 UTC,6H:6 hourly, 12h:12 hourly) - variable acronym [with level value] (e.g. hur850: relative humidity, 850 hPa) --> example: HADGEM2_SRA1B_1_6H_hur850 For this experiment 1 ensemble run was carried out. Technical data to this experiment: This dataset comprises the HadGEM2-AO run ahhpa (1/12/1999-1/01/2100).