Member nr. 1 of the NorESM2-MM spin up prepared for CMIP6, http://doi.org/10.22033/ESGF/CMIP6.8221. The simulation covers the years 0001-0120. A description is given in Seland et al. 2020 and figures of time series of key variables included in the Supplementary information of Seland et al. 2020. In addition, a detailed description of the simulation can be found here: https://noresmhub.github.io/noresm-exp/noresm2_mm_spin/noresm2_mm_spin1.html