1.We will use the ECCO global ocean circulation model as the foundation of model development and adaptation. This model is not a "general global circulation model" since it does include terrestrial dynamics nor does it include ocean drivers of atmospheric dynamics. Instead it is driven by meteorological inputs and outputs are limited to the state of the global ocean. Our project would use the entire global model despite the fact that our focus is on the southern ocean. Our group is interested and feels it is necessary to include regional models, but that there is no need to run other physical models. 2.The ECCO model does not have a well-developed biogeochemical model. This can be developed as part of the project by either our own efforts (meaning funded participants) or by simply plugging in biogeochemical models that have already been developed. It was pointed out that the biogeochemical models that have been developed are not very good, so that the former option (internal development) may be preferable since the project will include a new atmosphere/ocean, O2 closure scheme as well as an advanced and integrated float/satellite/coastal station monitoring system. 3.The model will focus on Fe, silicon, light, and grazing regulation of carbon dynamics, but nitrogen and O2 dynamics will be pursued.

4.We discussed the challenges of relaxing the constraint of the Redfield ratio for community production, respiration, and remineralization, but also recognized that this may be an important component of the model - particularly with regard to Carbon: FE and Carbon: Si ratios. One member of our group has developed such a model for the southern ocean, but it has never been tested. 5.A major challenge to the modeling effort is the fact that a new and high quality carbon dynamics model may be complex, and that the research tools to address such complexity such as genomic analysis of microbial community taxonomic composition or incorporation of higher trophic levels will levy a cost on computation time of a large scale model. Our discussion of having several types of models (e.g. 1 or 2 D models) in addition to the full 3D model to resolve this problem was unresolved and is worth further discussion.

There is interest for 1) a large-scale model, observationally constrained, with adequate biogeochemistry 2) regional models, for process studies, in well observed regions

The large-scale model may be bgc-SOSE, but there are advantages to global domain (How the Southern Ocean is related to the rest of the world might be more interesting than as an isolated system) Will provide boundary conditions for regional models Global model would be useful for atmospheric modelers It would be useful to have a solution for recent years, albeit crude Goal is to capture large-scale patterns and seasonal cycles Research question: how do we go from a tracer-based model optimization to something that uses chlorophyll and other satellite measurements? Gap analysis

Regional models could allow for “adventurous modeling” More complexity can be included End-to-end modeling would be a long-term goal Modeling as a research tool: understand what processes need to be represented in models, and how Goal is to check model against dense observations Gain insight, improve representation of processes Need to compile a list of existing regional models