Downscaling Global Climate Projections to the Ecosystems of the Bering Sea with Nested Biophysical Models

Funds are provided to model the physics and ecosystem structure of the Bering Sea. Change in climate forcing will be determined from coupled atmosphere-ocean general circulation model (GCM) simulations made for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). The twentieth century hindcasts from these models differ in terms of their ability to replicate past observed conditions; a subset of the better models will be used to project the trends, variability and uncertainty of the climate of the Bering Sea through the first half of the 21st century. This ensemble of GCM model results will be used primarily for dynamical downscaling, i.e., as initial and boundary conditions for high-resolution ocean model experiments with the Regional Ocean Modeling System (ROMS). The ROMS simulations are designed to properly handle physical processes known to be important on the Bering Sea shelf, such as sea ice, tides, and cross-shelf exchange; these results will form the direct input for embedded spatially-explicit nutrient-phytoplankton-zooplankton (NPZ) and food web model experiments.

This project is part of a larger program designed to develop understanding of the integrated ecosystem of the eastern Bering Sea shelf, a highly productive region of US coastal waters. This ecosystem is home to a major portion of the commercial fisheries of the US and also provides significant resources to subsistence hunters and fisherman of Alaska. The model will help to synthesize our current and developing understanding of how this system functions.