The GO8p0 model configuration was developed under the CLASS and CMEMS2 MERCATOR programmes. It is based on the GO8p0 configuration, developed under JMMP as the testbed for development of the ocean and sea ice components of the UK CMIP7 models HadGEM3-GC5 and UKESM2. It uses NEMO v4.0-beta and the SI3 sea ice model. It includes the Simmons (2004) tidal mixing parameterisation (originally omitted from NEMO v4.0), and extra modification to the vertical coordinate to stabilise z~ in a global domain, contributed by Jerome Chanut. The present configuration is described in Megann, A., Chanut, J. and Storkey, D, 2022. Assessment of the z~ time-filtered Arbitrary Lagrangian-Eulerian coordinate in a global eddy-permitting ocean model. Journal of Advances in Modelling Earth Systems (under review) Model Summary The model is implemented on the extended eORCA025 grid, described in Storkey, D., A.T. Blaker, P. Mathiot, A. Megann, Y. Aksenov, E.W. Blockley, D. Calvert, T. Graham, H.T. Hewitt, P. Hyder, T. Kuhlbrodt, J.G.L. Rae, and B. Sinha, 2018. UK Global Ocean GO6 and GO7: a traceable hierarchy of model resolutions. Geosci. Model Dev., 11, 3187–3213. DOI: 10.5194/gmd-11-3187-2018. This has global 1/4° resolution, with grid cell size of about 25km on the Equator, decreasing to about 8km at high latitudes, and includes a southwards extension to allow representation of the ice shelf, although the latter is not modelled explicity in the present configuration. There are 64 vertical levels: these have thickness 1m at the surface, increasing to 200m at depth. The ocean model physics settings in GO8p0 are selected to be as close as possible to those of GO6. Model Setup The following code was used in this configuration: svn co http://forge.ipsl.jussieu.fr/nemo/svn/NEMO/branches/UKMO/dev_r9950_GO8_package@10038 svn merge http://forge.ipsl.jussieu.fr/nemo/svn/NEMO/branches/UKMO/dev_r9950_GO8_package@10038 svn merge http://forge.ipsl.jussieu.fr/nemo/svn/NEMO/branches/UKMO/dev_r9950_GO6_mixing@10039 svn merge http://forge.ipsl.jussieu.fr/nemo/svn/NEMO/branches/UKMO/dev_r9950_old_tidal_mixing@10040 svn merge http://forge.ipsl.jussieu.fr/nemo/svn/NEMO/branches/2018/dev_r10057_ENHANCE03_ZTILDE@10643

Based on the initial GO8 configuration developed under the Joint Marine Modelling Programme (JMMP). This version includes Jerome Chanut's modifications to enhance the stability of z~ in a global configuration. Built on NEMO v4.0-beta: ocean physics as close as possible to that in GO6/GO7, with CICE sea ice component replaced with SI3.

{"references": ["Megann, A., Chanut, J. and Storkey, D, 2022. Assessment of the z~ time-filtered Arbitrary Lagrangian-Eulerian coordinate in a global eddy-permitting ocean model. Journal of Advances in Modelling Earth Systems (under review)"]}