Journal cover Journal topic
Geoscientific Model Development An interactive open-access journal of the European Geosciences Union
Geosci. Model Dev., 11, 681-696, 2018
https://doi.org/10.5194/gmd-11-681-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 3.0 License.
Model description paper
22 Feb 2018
AMM15: a new high-resolution NEMO configuration for operational simulation of the European north-west shelf
Jennifer A. Graham1,a, Enda O'Dea1, Jason Holt2, Jeff Polton2, Helene T. Hewitt1, Rachel Furner1, Karen Guihou2,3, Ashley Brereton2, Alex Arnold1, Sarah Wakelin2, Juan Manuel Castillo Sanchez1, and C. Gabriela Mayorga Adame2 1Met Office, FitzRoy Road, Exeter, EX1 3PB, UK
2National Oceanography Centre, Liverpool, L3 5DA, UK
3Departamento Oceanografía, Servicio de Hidrografía Naval, Buenos Aires, Argentina
anow at: Centre for Environment, Fisheries and Aquaculture Science, Pakefield Road, Lowestoft, NR33 0HT, UK
Abstract. This paper describes the next-generation ocean forecast model for the European north-west shelf, which will become the basis of operational forecasts in 2018. This new system will provide a step change in resolution and therefore our ability to represent small-scale processes. The new model has a resolution of 1.5 km compared with a grid spacing of 7 km in the current operational system. AMM15 (Atlantic Margin Model, 1.5 km) is introduced as a new regional configuration of NEMO v3.6. Here we describe the technical details behind this configuration, with modifications appropriate for the new high-resolution domain. Results from a 30-year non-assimilative run using the AMM15 domain demonstrate the ability of this model to represent the mean state and variability of the region.

Overall, there is an improvement in the representation of the mean state across the region, suggesting similar improvements may be seen in the future operational system. However, the reduction in seasonal bias is greater off-shelf than on-shelf. In the North Sea, biases are largely unchanged. Since there has been no change to the vertical resolution or parameterization schemes, performance improvements are not expected in regions where stratification is dominated by vertical processes rather than advection. This highlights the fact that increased horizontal resolution will not lead to domain-wide improvements. Further work is needed to target bias reduction across the north-west shelf region.

Citation: Graham, J. A., O'Dea, E., Holt, J., Polton, J., Hewitt, H. T., Furner, R., Guihou, K., Brereton, A., Arnold, A., Wakelin, S., Castillo Sanchez, J. M., and Mayorga Adame, C. G.: AMM15: a new high-resolution NEMO configuration for operational simulation of the European north-west shelf, Geosci. Model Dev., 11, 681-696, https://doi.org/10.5194/gmd-11-681-2018, 2018.

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This paper describes the next-generation ocean forecast model for the European NW shelf, AMM15 (Atlantic Margin Model, 1.5 km resolution). The current forecast system has a resolution of 7 km. While this is sufficient to represent large-scale circulation, many dynamical features (such as eddies, frontal jets, and internal tides) can only begin to be resolved at 0–1 km resolution. Here we introduce AMM15 and demonstrate its ability to represent the mean state and variability of the region.
This paper describes the next-generation ocean forecast model for the European NW shelf, AMM15...
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