DOI: 10.1594/pangaea.922028
title: Multibeam bathymetry processed data (Kongsberg EM 122 entire dataset) of RV MARIA S. MERIAN during cruise MSM67

description: Swath sonar bathymetry data used for that dataset was recorded during RV MARIA S. MERIAN cruise MSM67 using Kongsberg EM122 multibeam echosounder. The cruise took place between 31.08.2017 and 04.10.2017 off Svalbard. The cruise investigated the architecture of the rifted continental margin off East Greenland around the Jan Mayen fracture zone. The key issues were the margin segmentation and the location of the continent-ocean transition [DOI: edocx/00105895-1]. CI Citation: Paul Wintersteller (seafloor-imaging@marum.de) as responsible party for bathymetry raw data ingest creation of products and approval. During the MSM67 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 max 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/. Responsible person during this cruise / PI: unknown. 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. SVPs taken during this cruise were not sufficient enough to correct the recorded bathymetric data. Therefore sound velocity profiles were modelled using reference profiles from the world ocean atlas (S. Levitus, 1982), extracted and calculated through the MB-System program mblevitus by utilizing the DelGrosso equation. The surface sound speed has then been adapted according to the recordings during this cruise while there were no further corrections for roll, pitch and heave applied during postprocessing. A tide correction was applied, based on the Oregon State University (OSU) tidal prediction software (OTPS) that is retrievable through MB-System. CTD measurements during the cruise were sufficient to represent the changes in the sound velocity throughout the study area. 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 MSM67 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.
description: These data should not be used for navigational purposes.Dataset was submitted to PANGAEA and initial created in 2020. Data publication was approved in 2024.