Multibeam data were measured during R/V Polarstern cruise ARK-XXIII/3 along track lines of 7248 NM total length in the Arctic Ocean during transits and stationary work. Data were achieved on the transit from Iceland through the Northwestern Passage and the Beaufort Sea to the East Siberian Sea, crossing Northwind Ridge and Chukchi Plateau. The continental margin of East Siberian was surveyed by several wide spaced transects for almost three weeks. The Mendeleev Ridge and the surrounding deep sea bassins were investigated by a transect of about 1000 NM length, located at 80°-81°N. Lomonosov Ridge and Gakkel Ridge were also crossed. The multibeam sonar system Hydrosweep DS-2 was operated using 59 beams and 90° aperture angle, 120° in shallow water areas. The refraction correction was achieved utilizing 14 CTD profiles measured during the cruise or by the system's own cross fan calibration. The quality of data might be reduced during bad weather periods or adverse sea ice conditions. The dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.

The raw multibeam sonar data in SURF format are compressed as TAR archive with GZIP. One dataset contains a measurement period not exceeding eight hours. SURF data files can be processed using the software packages CARIS HIPS/SIPS or with the open source software package MB-System (http://www.ldeo.columbia.edu/res/pi/MB-System/). The source code for an application programming interface (API) to read and write SURF data is released by the Hydrosweep manufacturer Atlas Hydrographic, Bremen, and published under the GNU GPL. Contact mailto:infobathy@awi.de for data access.