GMD Geoscientific Model Development GMD Geosci. Model Dev. 1991-9603 Copernicus Publications Göttingen, Germany 10.5194/gmd-6-687-2013 The Norwegian Earth System Model, NorESM1-M – Part 1: Description and basic evaluation of the physical climate Bentsen M. https://orcid.org/0000-0001-5441-4063 1 2 Bethke I. https://orcid.org/0000-0002-6836-9838 1 2 Debernard J. B. 3 Iversen T. 3 4 6 Kirkevåg A. https://orcid.org/0000-0002-3691-554X 3 Seland Ø. 3 Drange H. 2 5 Roelandt C. 1 2 Seierstad I. A. 3 Hoose C. https://orcid.org/0000-0003-2827-5789 4 7 Kristjánsson J. E. 4 Uni Climate, Uni Research Ltd, P.O. Box 7810, 5020 Bergen, Norway Bjerknes Centre for Climate Research, P.O. Box 7810, 5020 Bergen, Norway Norwegian Meteorological Institute, P.O. Box 43, Blindern, 0313 Oslo, Norway Dept. of Geosciences, University of Oslo, P.O. Box 1047 Blindern, 0315 Oslo, Norway Geophysical Institute, University of Bergen, P.O. Box 7803, 5020 Bergen, Norway now at: ECMWF, Shinfield Park, Reading, RG2 9AX, UK now at: Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany 24 05 2013 6 3 687 720 Copyright: © 2013 M. Bentsen et al. 2013 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://gmd.copernicus.org/articles/6/687/2013/gmd-6-687-2013.html The full text article is available as a PDF file from https://gmd.copernicus.org/articles/6/687/2013/gmd-6-687-2013.pdf

The core version of the Norwegian Climate Center's Earth System Model, named NorESM1-M, is presented. The NorESM family of models are based on the Community Climate System Model version 4 (CCSM4) of the University Corporation for Atmospheric Research, but differs from the latter by, in particular, an isopycnic coordinate ocean model and advanced chemistry–aerosol–cloud–radiation interaction schemes. NorESM1-M has a horizontal resolution of approximately 2° for the atmosphere and land components and 1° for the ocean and ice components. NorESM is also available in a lower resolution version (NorESM1-L) and a version that includes prognostic biogeochemical cycling (NorESM1-ME). The latter two model configurations are not part of this paper. Here, a first-order assessment of the model stability, the mean model state and the internal variability based on the model experiments made available to CMIP5 are presented. Further analysis of the model performance is provided in an accompanying paper (Iversen et al., 2013), presenting the corresponding climate response and scenario projections made with NorESM1-M.

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