Circulation Modeling for the S.E. Bering Sea

Hermann, Stabeno, Haidvogel and Musgrave

During FY 97 we have expanded the original rigid lid Bering Sea circulation to include seasonal variability of the flows through passes at the edges of the model domain, and developed regional free-surface and global wind-and-tidal driven models for use by SEBSCC. As reported at the 1996 PICES meeting, results from the rigid-lid simulations exhibit markedly different patterns of barotropic circulation in winter vs. summer, with most of the summertime cross-shelf flux occurring as part of the Anadyr Stream. Development of the global Spectral Element Ocean Model (SEOM) and regional S-Coordinate Rutgers University Model (SCRUM) has focussed on four areas:

1) development of appropriate grids for SEOM and SCRUM. Unstructured grid generation software has been used to generate a horizontal grid for SEOM which will simultaneously serve the aims of both SEBSCC and recently funded North Pacific GLOBEC modeling programs (Fig. 1).

2) Wind-driven runs of SEOM in two-layer mode, and further development of a three-dimensional version of the model.

3) Tidal simulations of the Bering Sea using SCRUM, which compare favorably with observations (Fig. 2). Test simulations use global TOPEX altimetry data as a horizontal boundary condition. Several radiating boundary conditions have been tested using this development tool.

4) Implementation of coupling between SEOM and SCRUM. Combined tidal plus wind-driven output from SEOM is applied at the boundary of SCRUM using a technique based on results of the tidal tests.