The experiment CLM_20C_ZS contains Northern European regional climate simulations of the years 1960-1989 on a rotated grid (CLM non hydrostatic, 0.44 deg. hor. resolution, see http://www.clm-community.eu ). It is forced by the first (1) run of the global IPCC SRES 20C (EH5-T63L31_OM-GR1.5L40_20C_1_6H). The data represent 6 hourly values of a 20th century simulation with observed anthropogenic forcings (CO2, CH4, N2O, CFCs, O3 and sulfate). The model region starts at -19.36/-40.48 (lat/lon in rotated coordinates; centre of lower left corner of the domain) with rotated North Pole at 21.3/-175.0 (lat/lon). The number of grid points is 80/146 (lat/lon). The sponge zone (numerically unreliable boundary grid points) consists of 8 gridboxes at each border. EH5-T63L31_OM-GR1.5L40_20C_1_6H were nudged during the simulations (spectral nudging,von Storch, H., A spectral nudging technique for dynamical downscaling purposes. Mon. Wea. Rev, 2000 ) The regional model variables include two-dimensional near surface fields and atmospheric fields on 6 pressure levels (200, 500, 700, 850, 925 and 1000 hPa) for zonal and meridional wind, temperature and pressure. The time interval of the output fields is 3 hours. Please contact sga"at"dkrz.de for data request details. The output format is netCDF. Experiment with CLM 2.4.6 on HPC Cluster ( blizzard ).