Ocean modelling is a sophisticated and active field of research, with 3 main topics : 1. It requires continuous improvement and development of discretisation/parameterisation techniques (from idealised to realistic ocean configurations) adapted to fixed/variable structured/non-structured meshes. 2. The quality of model-based research and applications is also determined by implementation choices (e.g. physical and numerical parameters, initial and boundary conditions, specification of interactions with surrounding media) and sound integration strategies (e.g. multi-model, sensitivity or ensemble experiments). 3. Specific test cases, numerical and statistical metrics are needed to quantify model biases (possibly with uncertainties) with respect to well-chosen references (numerical criteria, theories, actual observations) and their sensitivity to key parameters over various time and space scales. Ocean modelling also benefits from synergies between these 3 topics, as assessment results feed back to model developers, and applications (e.g. global eddy-permitting ocean/sea-ice climate-oriented simulations) strongly constrain numerical choices and implementation strategies. Among the important applications of ocean modelling is the ability to assess biogeochemical problematics. Coupled circulation - biogeochemical models are used to assess 'hot topics' in marine science, such as ocean acidification or suboxia extension. A correct understanding and evaluation of the underlying biogeochemical processes are essential for these models to represent accurately the actual state and perform future projections. This session provides a forum for the latest work in these aspects of physical and biogeochemical ocean modelling at all space and time scales, in either stand-alone mode or in coupled mode (atmosphere, surface waves, sea/ground-ice, etc). This includes for instance numerical schemes, vertical coordinates, physical approximations and parameterisations, surface/lateral/bottom boundary conditions, interactions with sea-ice/land-ice/atmosphere, model integration strategies, innovative uses of ocean models (in idealized and realistic setups) for research and operational applications, and quantitative assessment methods of models and simulations. Contributions are also welcome on the subject of ocean model technology such as interfaces, interoperability and standardisation, new platforms and data formats.