The multibeam bathymetry from the Ryder 2019 Expedition spans from Thule in the south to the Lincoln Sea off Sherard Osborn Fjord in the north. The bathymetry reveals an abundance of submarine glacial landforms indicating past ice-flows of the North Greenland Ice Sheet trough Nares Strait and out of the mapped fjords.
Specifically, the ice-flow from Sherard Osborn Fjord, where Ryder Glacier is hosted, is revealed in detailed as this area was subjected to the most detailed mapping during the expedition. Two large bathymetric sills are evident, one located at the fjord mount and one just north of the 2019 location of the ice-tongue margin of Ryder Glacier.
The bathymetry will help to resolve ice dynamic processes and, in particular, the sensitivity of Ryder Glacier to inflow of subsurface water as it appears to, at least partly, be protected by the discovered bathymetric sills.
Brian Calder, Björn Eriksson, Kevin Jerram, Elizabeth Weidner, Felicity Holmes, Julia Muchowski, Abhay Prakash, Tamara Handl, Emelie Ståhl, Larry Mayer, Martin Jakobsson (2020). High-resolution bathymetry from the Ryder 2019 expedition to Northwest Greenland. Dataset version 1.0. Bolin Centre Database. https://doi.org/10.17043/ryder-2019-bathymetry
Jakobsson , M., L. A. Mayer, J. Farrell, and Ryder 2019 Scientific Party (2020), SWEDARCTIC-Ryder 2019 Report, 1-455 pp, Swedish Polar Research Secretariat, ISBN 978-91-519-5132-4.
The bathymetric data are provided as processed grids, divided into survey areas, with a grid cell size of 15 m. The grids are provided both on a polar stereographic projection (IBCAO Polar Stereographic, EPSG 3996, true scale at 75 degrees north) and unprojected WGS 84 in geographic coordinates (latitude and longitude). The horizontal datum is WGS 84 and the vertical datum is instantaneous sea level, implying that the vertical level has not been corrected for tides. For each projection, the bathymetric data grids are available in five formats: GeoTiff, netCDF, ASCII XYZ, ESRI Arc ASCII grid and Fledermaus surface. Data are also illustrated as JPEG images.
The data were acquired in August 2019 from Swedish icebreaker (IB) Oden during the Ryder 2019 expedition. A Kongsberg EM122 1° × 1°, 12 kHz, multibeam echo-sounder was hull-mounted in IB Oden. Position, heading and attitude data were received from a Kongsberg-Seatex Seapath 320 navigation unit (GPS and GLONASS) with attached MRU5 motion sensor. The exact speed of sound at the multibeam transducers was provided by a Valeport Mini SVS/T sound speed and temperature sensor mounted in the sea-chest in Oden’s hull, close to the multibeam transducer arrays. This was interfaced with the multibeam system directly. In addition, sound speed profiles for the entire water column were provided by CTD (Conductivity, Temperature, Depth) stations as well as XBT (Expendable Bathy Thermograph) probes.
The data was collected in a mixture of sea-ice conditions, ranging from 5/10 to 8/10 coverage. Navigation was provided by a Seatex Seapath 320 without local augmentation as this is not available in the area. Sound speed correction was done regularly using data from a Seabird 911+ CTD (conductivity, temperature depth) or Valeport SVP (sound velocity profiler).
The Ryder expedition started and ended in US Air Force Base Thule, Northwest Greenland, and lasted from August 5 to September 10, 2019. The main target was Sherard Osborn Fjord where Ryder Glaciers drains the north-western Greenland Ice Sheet. Included in the expedition survey areas were also Petermann Fjord and adjacent Hall Basin, northern Nares Strait and an area northeast of Ellesmere Island in the Lincoln Sea. It was an Explorers Club Flag Expedition carrying Flag #51. It was multidisciplinary with a broad range of data collected.
Department of Geological Sciences
SE-106 91 Stockholm
Earth science > Oceans > Bathymetry/seafloor topography
Ocean > Arctic Ocean
Ryder 2019 expedition
Bolin Centre Database