Arctic Observing Network: Continuing the Beaufort Gyre Observing System in 2018-2021 to Document and Enhance Understanding of Arctic Freshwater Transformations and Fate

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The western part of the Arctic Ocean contains a large amount of freshwater (more than 23,000 cubic kilometers which is comparable with the volume of fresh water stored in all the Great Lakes). Our project uses samples from ships and moored instruments to study the mechanisms controlling the amount of freshwater and other ocean properties in the western Arctic Ocean under different climate conditions. Changes in the western Arctic system are driven by changes in the Arctic and global climate systems while at the same time they are strong enough to influence both the weather and climate in the Northern Hemisphere. What we learn on this project will allow us to predict changes in the Arctic Ocean and is important for oil and gas exploration, shipping, navigation, tourism, and military operations.This Arctic Observing Network project will continue for 2018-2019 the Beaufort Gyre Observing System operations begun in 2003 designed to document the unprecedented changes in sea ice and ocean parameters that are presently occurring in the region. We will continue measuring time series of temperature, salinity, currents, geochemical tracers, sea ice draft, and sea level using bottom-anchored moorings and shipboard measurements. Ship-based synoptic sampling covering the Beaufort Gyre will take place during the summer of 2018 in collaboration with scientists from Canada and Japan, with shared logistic expenses, to augment the year-round mooring measurements. Temperature, salinity, oxygen, nutrients, barium, and 18O will continue to be measured at standard locations along sections at 140°W and 150°W longitudes, and ~75°N and ~78°N latitudes using a shipboard CTD/rosette to continue the long-term time series started in 2003. Samples that provide information on longer time-scales, such as CFCs and carbon tetrachloride, alkalinity, total CO2, dissolved inorganic carbon, and tritium/3He, will be collected less frequently. Expendable CTDs that profile to 1100 m depth will be used between CTD/rosette casts to increase spatial resolution of the temperature and salinity fields. The project will be coordinated with other elements of the National Science Foundation?s Arctic Observing Network to enhance effectiveness and interconnections of observational activities, and the field program will continue to accommodate other National Science foundation- funded projects when possible. Data will be available on the project website and at the National Science Foundation's Arctic Data Center.