DOI: 10.1594/pangaea.893200
title: Gridded EM122 multibeam-echosounder bathymetry of cruise MSM36 - Gulf of Cadiz

description: Bathymetry based on data recorded during RV MARIA S. MERIAN cruise MSM36 between 18.02.2014 and 17.03.2014 at the Moroccan continental margins. The cruise carried out multidisciplinary research on the long-term development of cold-water coral ecosystems in selected areas along the Moroccan continental margins in the Mediterranean Sea and in the Atlantic Ocean. The key instrument to be used during this expedition was the Bremen Deep Sea Drill Rig MeBo. CI Citation: Paul Wintersteller (seafloor-imaging@marum.de) as responsible party for bathymetry post-processing and its products. Description of processed data sources: During the RV MARIA S. MERIAN cruise MSM36, the Kongsberg EM122 multibeam echosounder with a nominal sounding frequency of 12 kHz was utilized. 288 beams (and up to 800 soundings with equidistant and dual swath mode) with a 2°(TX)/2°(RX) footprint are formed for each ping while the seafloor is detected using amplitude and phase information for each beam sounding. For further information consult https://www.km.kongsberg.com/. During the cruise, in the west of Melilla the acquisition computer of the EM122 failed, but could be repaired before entering the Atlantic region. The rest of the time the system was stable. Responsible person during this cruise / PI: Stefanie Gaide (sgaide@marum.de). 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 suite (Caress, D.W., and D.N. Chayes, MB-System Version 5.5, open source software distributed from the MBARI and L-DEO web sites, 2000-2012.) was utilized for this purpose. A tide correction was applied, based on the Oregon State University (OSU) tidal prediction software (OTPS) that is retrievable through MB-System. CTD measurements taken during MSM36 were sufficient to represent the changes in the sound velocity throughout the study area. A part of the survey lines were missing the installation parameters due to the failure of the acquisition computer, therefore, the pitch, heave, heading and sonar offsets of the lever arms had to reapplied for these lines (mbset). Bathymetric data has been manually cleaned for existing artefacts with mbeditviz. NetCDF (GMT) grids of the product and the statistics were created using mbgrid No total propagated uncertainty (TPU) has been calculated to gather vertical or horizontal accuracy. The currently published bathymetric grid of the cruise has a resolution of 125 m. 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. All grids produced are retrievable through the PANGAEA database (www.pangaea.de). Chief Scientist: D. Hebbeln CR: https://www.tib.eu/de/suchen/id/awi%3Adoi~10.2312%252Fcr_msm36/ CSR: http://www.bsh.de/aktdat/dod/fahrtergebnis/2014/20140066.htm A special thanks goes to Maren Bender who helped to create this product.