Understanding the Arctic as a System

NABOS Technology

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Moorings

Moorings are an important element of the program. Some of these moorings have been maintained since 2002.

Moorings from these locations have already provided key information about strong EB warming and have helped estimations of transit times required for the signal to travel from Fram Strait to the basin interior.

Locations of moorings, cross-sections, and Lagrangian drifters. Cruises will feature repeated oceanographic sections and deployment of Lagrangian drifters and moorings (including mooring section at the Laptev Sea slope). We refer to the Amundsen and Nansen Basins collectively as the Eurasian Basin (EB), distinct from the Makarov Basin.

Technical information

Distributed moorings

The mooring locations in the Laptev Sea (M1 and M3 moorings, above) and East Siberian Sea (M9 mooring) are reliable climatological sites; data from these locations were used in the past for monitoring climatic changes [e.g. Polyakov et al. 2005; Dmitrenko et al. 2008a].

The mooring site north of Severnaya Zemlya (M5 mooring) is close to the frontal zone between the AW Fram Strait and Barents Sea branches and to a polynya region; therefore, it is more susceptible to local processes like down-slope cascading of dense shelf waters. Data from this mooring bridges snapshot CTD observations taken at the 90°E cross-slope section carried out every other year. These moorings will use “conventional,” reliable equipment: fixed-depth CTDs, SBE-37s (“microcats”) to measure temperature and salinity, and ADCPs to measure currents.

Previous observations have demonstrated rather uniform vertical structure of the boundary current in the AW and halocline; thus, the proposed design should be sufficient to capture AW transports. These moorings complement snapshot ship-based observations at distributed cross-sections providing climatologic context to the snapshot measurements.

Two of the moorings (M1 and M9) will be equipped with upward-looking bottom-tracking ADCPs to measure current profile and to monitor ice drift; they will also have Upward Looking Sonar (ULS) for ice draft measurements. CTD chains affixed to two moorings (M5 and M3) will be located above major flotation to measure surface boundary layer T and S.

Ocean Bottom Pressure (OBP) variations will be tracked at the M1 and M9 moorings using Sea-Bird BPR-53 meters. We will compare these observations with Dynamic Ocean Topography (DOT) derived from the CryoSat-2 altimeter to test satellite-derived estimates of Arctic Ocean circulation [Kwok and Morison, 2011] and freshwater distribution [Morison et al., 2011]

Cross-slope mooring section
Lagrangian buoys (partners' programs)