Description and evaluation of NorESM1-F: A fast version of the Norwegian Earth System Model (NorESM)

Chuncheng Guo*, Mats Bentsen, Ingo Bethke, Mehmet Ilicak, Jerry Tjiputra, Thomas Toniazzo, Jörg Schwinger, Odd Helge Otterä

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

54 Citations (Scopus)

Abstract

A new computationally efficient version of the Norwegian Earth System Model (NorESM) is presented. This new version (here termed NorESM1-F) runs about 2.5 times faster (e.g., 90 model years per day on current hardware) than the version that contributed to the fifth phase of the Coupled Model Intercomparison project (CMIP5), i.e., NorESM1-M, and is therefore particularly suitable for multimillennial paleoclimate and carbon cycle simulations or large ensemble simulations. The speed-up is primarily a result of using a prescribed atmosphere aerosol chemistry and a tripolar ocean-sea ice horizontal grid configuration that allows an increase of the ocean-sea ice component time steps. Ocean biogeochemistry can be activated for fully coupled and semi-coupled carbon cycle applications. This paper describes the model and evaluates its performance using observations and NorESM1-M as benchmarks. The evaluation emphasizes model stability, important large-scale features in the ocean and sea ice components, internal variability in the coupled system, and climate sensitivity. Simulation results from NorESM1-F in general agree well with observational estimates and show evident improvements over NorESM1-M, for example, in the strength of the meridional overturning circulation and sea ice simulation, both important metrics in simulating past and future climates. Whereas NorESM1-M showed a slight global cool bias in the upper oceans, NorESM1-F exhibits a global warm bias. In general, however, NorESM1-F has more similarities than dissimilarities compared to NorESM1-M, and some biases and deficiencies known in NorESM1-M remain.

Original languageEnglish
Pages (from-to)343-362
Number of pages20
JournalGeoscientific Model Development
Volume12
Issue number1
DOIs
Publication statusPublished - 21 Jan 2019

Bibliographical note

Publisher Copyright:
© Author(s) 2019.

Funding

Acknowledgements. Chuncheng Guo and Mats Bentsen acknowledge the Ice2Ice project that has received funding from the European Council under the European Community’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement no. 610055. Jerry Tjiputra acknowledges the Research Council of Norway funded project ORGANIC (239965) and funding from the Bjerknes Centre for Climate Research (BIGCHANGE). Jörg Schwinger was supported by the Research Council of Norway through project EVA (229771). Ingo Bethke was supported by the projects BFS BCPU and RCN INES (270061). The simulations were performed on resources provided by UNINETT Sigma2 – the National Infrastructure for High Performance Computing and Data Storage in Norway (nn4659k, ns4659k, nn2345k, ns2345k). Data from the RAPID-WATCH MOC monitoring project are funded by the Natural Environment Research Council and are freely available from http://www.rapid.ac.uk/rapidmoc/ (last access: 14 January 2019).

FundersFunder number
BIGCHANGE229771, 270061
Bjerknes Centre for Climate Research
European Council
Seventh Framework Programme610055
Natural Environment Research Council
European Research Council
Norges Forskningsråd239965

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