http://bolin.su.se/data/oden-ryder-2019-bathymetry-1 Brian Calder, Björn Eriksson, Kevin Jerram, Elizabeth Weidner, Felicity Holmes, Julia Muchowski, Abhay Prakash, Tamara Handl, Emelie Ståhl, Larry Mayer, Martin Jakobsson Bolin Centre Database 2020 Datafile Marine Bathymetry Geophysics Arctic Ocean Bathymetry Seafloor morphology Multibeam Greenland Ryder Glacier Ryder 2019 expedition Icebreaker Oden Earth science > Oceans > Bathymetry/seafloor topography Martin Jakobsson 2020-08-12T02:00:00+00:00 English 1 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 in polar stereographic projection (IBCAO Polar Stereographic, EPSG 3996, true scale at 75 degrees north) and unprojected WGS 84 and 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 four formats: GeoTiff, netCDF, ASCII XYZ and ESRI Arc ASCII grid. 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.