# MODELING WORKING GROUP REPORT

## First U.S. Southern Ocean GLOBEC Science Investigator Meeting
Arlington, VA
25-26 May 2000

## Eileen Hofmann and Glenn Flierl, Working Group Co-Chairs

There are several existing biological, sea ice, and circulation models for the Antarctic marine system. The refinement of some of these models and the development of additional models have been proposed as part of several programs that are funded through the U. S. SO GLOBEC program. We felt that a listing of the existing and proposed models was not a useful exercise. Rather, we felt that a discussion of the areas in which models could make a large contribution to the SO GLOBEC program and the general understanding of the Southern Ocean would be more useful. The research areas that we identified for modeling studies are as follows.

Area I: Theoretical studies of the basic physics of continental shelf circulation, coupled shelf-ocean circulation, density-driven circulation, exchanges between the shelf and the Antarctic Circumpolar Current, transport and flux in semi-enclosed regions, and ocean-ice interactions

Area II: Consistent description of the shelf and coupled-shelf circulation from the available data sets

This topic can be addressed through the development of optimal interpolation schemes that contain dynamics appropriate for the west Antarctic Peninsula shelf system and through data assimilation into circulation models

Addressing the above two research areas should be done with a range of circulation models that extend from simple conceptual models to primitive equation eddy-resolving circulation models.

Area III: Study of aggregation behavior (e.g., krill) and the study of trophic interactions in aggregated versus non-aggregated systems

It was felt that this research area was of enough general interest to warrant convening a workshop. Such a workshop could be sponsored by U.S. and International GLOBEC and possibly SCAR and SCOR.

Area IV: Sea ice biology and water column interactions

Area V: Overwintering strategies for krill, krill reproductive potential, size/age dependence in metabolic rates, and effects of available food supply on overwinter success of krill

A recent model (Hofmann and Lascara, 2000, MEPS) that simulated the growth and development of Antarctic krill might be a useful tool to make available to all program investigators to allow integration and testing of data sets that will be collected to address the issues related to krill overwintering, metabolism and reproductive potential. The krill model could serve as a program community model.

Area VI: Coupling of lower trophic level models to those for top predators

This type of model would allow investigation of the characteristics that make a good or bad environment from the perspective of the top predator. The coupling of top predators to their prey fields is an area of modeling that is only now being developed. SO GLOBEC has the opportunity to make significant contributions in this area.

Area VII: Improved parameterizations for life history and metabolic process in models

The many data sets collected as part of SO GLOBEC should be sufficient to allow development of seasonal and age/stage parameterizations for models.

Area VIII: Coupling of lower trophic level and top predator models to circulation models.