| Summary: | This Arctic Observing Network (AON) project will conduct Beaufort Gyre Observational System (BGOS) operations begun in 2003 during 2009-2014 to document the unprecedented changes in sea ice and ocean parameters that are presently occurring in the Beaufort Gyre (BG) region. The project will measure time series of temperature, salinity, currents, geochemical tracers, sea ice draft, and sea level using bottom-tethered moorings and shipboard measurements. Three moorings will acquire precise data on the variations of the vertical distribution of seawater properties, bottom pressures and sea ice draft at sites: 75N and 150W; 78N and 150W; and 77N and 140W. Ship-based sampling covering the entire BG, will be performed in collaboration with scientists in Canada and Japan with shared logistics expenses, to augment the year-round mooring measurements. Temperature, salinity, oxygen, nutrients, barium and delta-18O will be measured and analyzed at 30 standard locations along 140W, 150W, ~ 75N and ~78N sections using shipboard CTD (conductivity, temperature, and depth)/rosette to provide long-term time series started in 2003. Samples that provide information on longer time-scales, such as CFCs (chlorofluorocarbons) and carbon tetrachloride, alkalinity, total CO 2 , dissolved inorganic carbon and tritium/3He, will be collected less frequently. Between CTD/rosette casts, expendable CTDs that profile to 1100 m depth will be used to increase spatial resolution of the temperature and salinity fields. The proposed work will be coordinated with the basic elements of AON to enhance effectiveness and interconnections of observational activities.
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