Contribution from NOC (eORCA12) #12
Description
Name of your institution / research group
National Oceanography Centre - Marine Systems Modelling Group
Ollie Tooth, Adam Blaker, Andrew Coward.
https://noc.ac.uk/science/research-areas/marine-systems-modelling
GitHub IDs of proposed participants to the intercomparison project
oj-tooth, atb299, accowa
Detail about your model codebase
National Oceanography Centre Near-Present Day (NPD) eORCA12 ocean sea-ice configuration using NEMO v4.2 based on UK Global Ocean and Sea Ice configuration version 9 (GOSI9), which has been documented in Guiavarc’h et al. (2025).
- eORCA12 with a nominal resolution of 1/12 at the equator.
- Non-linear free surface, 75 vertical z* levels, partial step topography.
- SI3 sea ice model.
- TEOS-10 EoS
Complete documentation of NPD eORCA12 configuration available: https://noc-msm.github.io/NOC_Near_Present_Day/deep_dives/
v0.9.0 codebase available via Zenodo DOI: https://doi.org/10.5281/zenodo.15310353
Detail about your model experiment
- Initial Conditions: conservative temperature and absolute salinity fields from the World Ocean Atlas 2023 (Reagen et al., 2024) Climate Normal (30-year average) corresponding to 1971-2000 are used.
- Atmospheric Forcing: climatologically adjusted version of the ERA-5 atmospheric reanalysis + ECMWF bulk formulae (IFS documentation, cy45).
- Run Length: 1976-2024 (updated quarterly with 3-month lag).
[Climatological adjustment is applied to the ERA-5 hourly 2 m temperature field over regions where (ERA-5) sea ice cover > 0%. Climatological offset factors are determined by calculating the difference between the long-term mean (1960-2019) monthly 2 m temperature climatologies of ERA-5 and JRA55-do. To avoid step-like transitions between monthly adjustments, 2 m temperature offset factors are linearly interpolated in time to produce hourly surface forcing fields.]
Complete details of NPD eORCA12 ERA5v1 simulation is available via: https://noc-msm.github.io/NOC_Near_Present_Day/deep_dives/