http://bolin.su.se/data/oden-oso-2010-bathymetry-1 Björn Eriksson, Nina Kirchner, Frank Nitsche, Rezwan Mohammad, Richard Gyllencreutz Bolin Centre Database 2021 Datafile Marine Bathymetry Geophysics Southern Ocean Bathymetry Seafloor morphology Multibeam OSO 2009/10 expedition Icebreaker Oden Earth science > Oceans > Bathymetry/seafloor topography > Bathymetry Martin Jakobsson 2021-11-04T14:12:41+00:00 English 1 The bathymetric data are provided as processed grids, divided into survey areas, with a grid cell size of 15⁠ – ⁠100 m. The grids are provided both in polar stereographic projection (Antarctic Polar Stereographic, [EPSG 3031](https://epsg.io/3031), true scale at 71° south) and in geographic coordinates ([WGS 84](https://en.wikipedia.org/wiki/World_Geodetic_System_1984 "Wikipedia: World Geodetic System 1984"), 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 austral summer 2009/10 from Swedish icebreaker (IB) Oden during the OSO 2009/10 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 were 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 OSO 2009/10 expedition started in McMurdo Station, Antarctica, and ended in Punta Arenas, Chile, and lasted from February 8 to March 12, 2010. IB Oden was chartered by the US National Science Foundation (NSF) to break an ice channel to the McMurdo station on the Ross Sea, to enable researchers to conduct trans-disciplinary studies in the Antarctic region. On the voyage back to South America, the icebreaker served as a research platform for the OSO expedition.