DOI: 10.1594/pangaea.912850
title: Gridded bathymetry from EM122 multibeam echosounder of R/V Maria S. Merian cruise MSM30

description: Bathymetry data was acquired during R/V MARIA S. MERIAN cruise MSM30 in the northwestern Barents Sea between 16.07.2013 and 15.08.2013. The cruise aimed drilling glacigenic sediments with the MARUM seafloor drill rig MeBo in the Kveithola Trough, a palaeo-ice stream depositional system in the western Barents Sea. The main scientific objective was to reconstruct high- and deglacial icestream and sea-ice dynamics as a result of climatic variability. Intensive multibeam mapping extended the existing regional bathymetric map, illustrating the various morphological elements at the slope (shelf-edge gullies, young landslides, elongated slide scars) and on the shelf (current leading channels, ice plough mark pattern, grounding-zone wedge boundaries). CI Citation: Paul Wintersteller (seafloor-imaging@marum.de) as responsible party for bathymetry raw data ingest and approval.Description of processed data sources:During the MSM30 cruise, the hull-mounted KONGSBERG EM122 multibeam echosounder (MBES) was utilized to perform bathymetric mapping in middle to deep water depths. Two linear transducer arrays in a Mills Cross configuration transmit acoustic signals of a nominal sonar frequency of 12 kHz. With 432 soundings per swath, the emission cone has a dimension of 150° across track and 2° along track. With a reception obtained from 288 beams, the actual beam footprint is 2° by 2°. Depending on the roughness of the seafloor, the swath width on a flat bottom is generally maximum six times the water depth. For further information on the system, consult https://www.km.kongsberg.com/. The position and depth of the water column is estimated for each beam by using the detected two-way-travel time and the beam angle, ray-traced through the water column, utilizing a proper sound speed profile. During MSM30, the multibeam surveys were generally conducted at a speed of 8 knots. Throughout the whole cruise generally a swath angle of about 130° was used, while the beam spacing was set to medium and the pitch stabilization was on. . Responsible person during this cruise / PI: A. Özmaral.Description of data processing:Postprocessing and products were conducted by the Seafloor-Imaging & Mapping group of MARUM/FB5, responsible person Paul Wintersteller (seafloor-imaging@marum.de). The open source software MB-System (Caress, D. W., and D. N. Chayes, MB-System: Mapping the Seafloor, https://www.mbari.org/products/research-software/mb-system, 2017) was utilized for this purpose. Tide and a sound velocity profile were applied to the MSM30 data; there were no corrections for roll, pitch and heave. Using Mbeditviz, artefacts were cleaned manually. NetCDF (GMT) grids of the edited data as well as statistics were created with mbgrid. The published bathymetric EM122 grid of the cruise MSM30 has a resolution of 35 m. No total propagated uncertainty (TPU) has been calculated to gather vertical or horizontal accuracy. A higher resolution is, at least partly, achievable. The grid extended with _num represents a raster dataset with the statistical number of beams/depths taken into account to create the depth of the cell. The extended _sd -grid contains the standard deviation for each cell. The DTMs projections are given in Geographic coordinate system Lat/Lon; Geodetic Datum: WGS84. All grids produced are retrievable through the PANGAEA database (www.pangaea.de).Chief Scientist: Till HanebuthCR: https://www.tib.eu/de/suchen/id/awi%3Adoi~10.2312%252Fcr_msm30/CSR: https://www2.bsh.de/aktdat/dod/fahrtergebnis/2013/20130053.htm