Ocean and ice model development

Ocean and sea-ice models are the primary tool for research carried out by the climate, cryosphere and oceans group. The model development team is responsible for developing ocean models, in collaboration with the Nucleus for European Modelling of the Ocean (NEMO) consortium and the Community Ice Code (CICE) sea-ice model based at Los Alamos National Laboratory. The group's role is to develop and improve the global configurations that are used at the Met Office. These are run both in ocean-ice forced mode using the DFS4 (Bordeau et al., 2010) and as part of the global climate configuration of the Met Office climate prediction model: HadGEM3 family coupled climate model. They are also used within the Met Office seasonal prediction system: GloSea5 seasonal forecasting and short-range Ocean Forecasting Research systems. Assessment and evaluation of the models against current and past climate is an important part of this work.

The requirement for high resolution climate models means that it is no longer practical to maintain ocean and sea ice components which have a geographic North Pole. The grid convergence of a regular latitude-longitude grid requires not just filtering to maintain stability but also the insertion of a polar island. The approach that has been taken is to introduce new ocean and sea ice components that are formulated with generalised orthogonal coordinates and are therefore able to employ a tripolar grid as shown by the figure above (Murray, 1996).

Key aims

• To provide the ocean and sea-ice components of the Met Office climate models.

• To improve representation of physical processes in the ocean and sea ice across a range of time and spatial scales.

• To evaluate the ocean and sea ice models against observed climate data in order to understand the causes of errors in the model climate and reduce these errors.