This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
Recent measurements of the Bering Strait throughflow fluxes find strong seasonal and interannual variability, so far unpredictable ? the heat flux increase from 2001 to 2004 is enough to melt an 800 km by 800 km area of 1 m thick ice, and the internannual variability in freshwater is likely ~ 30%. Yet, understanding of what sets the properties and variability of the throughflow is still rudimentary and our ability to measure these fluxes accurately is constrained by lack of access to the most nutrient-rich western half of the strait (which lies in Russian waters) and difficulties in deploying instruments within the upper water column (due to potential ice-keel damage to instrumentation), where stratification and coastal boundary currents (especially the Alaskan Coastal Current in the eastern channel) contribute significantly to freshwater and heat fluxes.
Given the significant role of Pacific waters in the Arctic, quantifying the Bering Strait throughflow and its properties is important to understanding the present functioning of the Arctic system, as well as the causes and prediction of present and future Arctic change. This makes a Bering Strait monitoring system a vital component of the Arctic Observing Network (AON). Thus, this proposal is for an international project to: 1) measure the velocities and water properties of the Bering Strait throughflow, and quantify oceanic fluxes of volume, freshwater, heat and nutrients through the strait; 2) design (and calibrate) an optimum monitoring system for oceanic fluxes through the Bering Strait on daily to interannual time scales, using in situ, satellite, and numerical weather prediction results; and 3) utilize the system design to improve and extend previous Bering Strait flux estimates back several decades and provide uncertainty estimates for all fluxes.
To obtain the necessary data to design and calibrate an effective, efficient monitoring system for the strait, the project focuses on a 3-year deployment (2010-2013) of an 8-mooring array, supported by annual CTD surveys, satellite data, and model winds. The array includes upper and lower layer temperature, salinity and velocity measurements in both channels of the strait and at one ?climate? site to the north, and across-strait pressure measurements. Ship time and acquisition of Russian working permissions are supported by NOAA.
