The multibeam echo sounder (MBES) data was collected from the 10.07.2022 (09:24 UTC) when leaving the Northern Mariana EEZ to the 18.07.2022 (00:24 UTC) before entering the EEZ close to the Aleutian Islands, Alaska with the Kongsberg EM122 on RV SONNE in the North Pacific Ocean (SO292/2). The deep-water MBES EM122 operates with an acoustic frequency of 12 kHz and a beam opening angle of 0.5° x 1°. The raw and unprocessed bathymetric and backscatter data is stored in Kongsberg format (.all), each containing up to 30 min of data. The therein included time, motion and position data (WGS84, geographic) was measured by the Kongsberg Seapath system on board. During the acquisition the echo sounder was monitored as well as settings and filter adjusted according to the environment. The transit speed was up to 13 knots. The swath opening angle was set between 60° and 65° resulting in a swath width of about 22 km in 5,000 m water depth. The Ping Mode was set to Auto, which enabled the system to use continuous wave pulses in shallow modes and frequency modulated pulses in deep modes. Further, high density and dual swath mode were continuously applied. As the data was collected during transit, no specific surveys were performed. When sound velocity related artefacts were noticed in the MBES data, the sound velocity profile in the MBES acquisition software SIS was updated. Profiles were measured using XSVs (Expendable Sound Velocity) up to a depth of 2,000 m on the 11.07.2022, 13.07.2022 and 16.07.2022. Additionally, synthetic SVPs extracted form the World Ocean Altlas 2009 from NOAA (Levitus, 2013) using the software "Sound Speed Manager" (developed by the UNH Center for Coastal and Ocean Mapping and NOAA Coast Survey Development Laboratory (CSDL)) were applied. The SVP data is not part of this submission but can be extracted from the .all files.

These data should not be used for navigational purposes.