Inset map shows schematic Bering Sea Circulation from Stabeno et al 1999. Rest of figure shows simulated Bering Sea surface velocity for August 2005 from the BESTMAS high resolution ocean-ice model (see below for details).
Sea-ice and the Bering Sea Ecosystem
High Resolution Modeling studies of present and future Bering Sea circulation
University of Washington
1013 NE 40th Street, Seattle, WA 98105, U.S.A.
Bering Sea - lying at the northern end of the Pacific Ocean and north
of the Aleutian Chain - is the source of over 50% of the total US
fish catch and the home to immense populations of birds and marine
mammals. The Bering Sea ecosystem is strongly tied to the seasonal
sea-ice, which influences the oceanic environment of the region and
also provides a habitat for many species. Recent years have shown
significant climate regime shifts in the Bering Sea. As part of
the new NSF Bering Ecosystem Study (BEST), we plan to use a
state-of-the-art numerical ocean-ice model to investigate prior (and
predict future) changes in the Bering Sea ice cover and study the
impacts of these changes on Bering Sea marine and eco-systems.
Bering Sea is the
source of over 50% of the total US fish catch and the home to immense
populations of birds and marine mammals. This
extraordinarily productive ecosystem is vulnerable to the significant
climate regime shifts that have occurred over recent decades and will
surely have substantial economic and social implications. These regime
shifts are closely linked to a warming of the atmosphere and ocean, and
the coincident retreating of the sea ice cover,
both with strong interannual and decadal variability.
The ice cover is a key player in the eastern Bering ecosystem. It affects ocean temperature, salinity, stratification, light distribution, and transport of nutrients and carbon, by modifying surface light availability and air-sea exchanges of heat, freshwater, momentum, and biogenic gasses. All these are important for ecosystem dynamics. Ice is also a vital habitat for many species. Whether the retreating ice cover and the warming regime shifts are due to natural climate variability or to anthropogenic climate change, for economic/social reasons it is essential to understand past change in the eastern Bering climate and ecosystem and to predict the timing and scope of future change.
We propose a study of the historical and contemporary changes of the Bering Sea ice cover and the impacts of these changes on Bering Sea marine climate and physical-biological processes. Additionally, we will investigate future changes of the eastern Bering marine environment under global warming scenarios
objectives are to:
1) Simulate the historical evolution and regime shifts of the eastern Bering ice-ocean system from 1970 to the present, to quantify the ice-ocean climate changes that have affected the ecosystem;
2) Identify key linkages among the atmosphere, sea ice, and ocean, to understand mechanisms affecting physical forcings of biological processes;
3) Examine the interactions between the Bering Sea climate and the Pacific and Arctic climate, to assess the Bering climate system’s vulnerability to and influence on hemispheric climate change;
4) Estimate the impacts of projected future anthropogenic global climate change (including an ice-free regime) on the eastern Bering Sea system, specifically focusing on changes in ice-ocean climate and the physical forcings of biological systems, to provide a future change assessment to local and national stakeholders, including Native and fishing communities, and the general public.
|The BESTMAS coupled ice-ocean
Bering Ecosystem STudy ice-ocean Modeling and Assimilation System
Our studies will develop and run a state-of-the-art coupled ice-ocean model for synthesis and modeling of the eastern Bering Sea. Although significant progress has been made modeling Bering ocean processes (e.g. Hermann et al., Winsor et al., Wang; Clement), most of the previous models did not incorporate a sea-ice component.