Comparison of Seabeam 2112 and SCAMP bathymetry data along the Gakkel Ridge: preliminary mapping results from the Healy0102 Arctic C ruise

As part of an international effort to investigate geological processes at Earth's slowest spreading mid-ocean ridge and to map the largely unexplored Arctic Ocean, the US Coast Guard Cutter Healy and the German research vessel Polarstern surveyed and sampled the Gakkel Ridge in the summer/fall of 2001. The expedition was planned using bathymetry and sidescan data acquired by the SCAMP interferometric sonar mounted on the hull of the nuclear-powered submarine USS Hawkbill in 1998 and 1999. In addition to seismic surveys, dredging and underway oceanographic data collection, both icebreakers participating in the 2001 program acquired multibeam sonar data: Seabeam 2112 from the USCG Healy and Hydrosweep from the R/V Polarstern. The acquisition of these two new datasets presents the opportunity to compare GPS-navigated data collected using multibeam systems operating in ice-covered waters with interferometric data collected aboard a nuclear-powered submarine operating beneath the permanent ice pack. Comparisons reveal that even in 7/10 and 8/10 ice conditions, the quality of the hull-mounted bathymetry data are equivalent or even superior to the interferometric bathymetry data. Similar features detected in both datasets allow the GPS-navigated Seabeam 2112 data to resolve navigational ambiguities in data collected using the USS Hawkbill's inertial navigation system.