Publication Date:
2023-03-03
Description:
Bathymetry data was acquired during R/V METEOR cruise M84/4 at the Galician Shelf off Northwest Spain in the Northeast Atlantic between 01.05.2011 and 28.05.2011. The main objectives of the cruise were the investigation of sediment transport processes from shallow to deep waters, understanding sediment dynamics, analysis of material downslope processes and the reconstruction of modern and past environmental conditions. The cruise comprised seismic, sedimentological, magnetic, geochemical and palaeoceanographic methods.
Extensive bathymetric mapping during M84/4 based on the multibeam echosounders (MBES) KONGSBERG EM710 and EM122 provided the basis for sediment coring and additional investigations. Hydroacoustic data revealed the diverse morphology in the study area, driven by both sedimentary and tectonic processes, including contouritic deposits, slope gullies, canyon/channel systems, ridges and seamounts. The sub-bottom profiler PARASOUND, multichannel seismics, ADCP, several coring devices and the electromagnetic profiler MARUM-NERIDIS III complemented the research programme of the cruise.
CI Citation: Paul Wintersteller (seafloor-imaging@marum.de) as responsible party for bathymetry raw data ingest and approval.
Description of the data source:
During the M84/4 cruise, the hull-mounted KONGSBERG EM710 multibeam echosounder (MBES) was utilized to perform bathymetric mapping of high resolution in water depths of 3 m to – theoretically – 2000 m. Best quality data is, however, achieved in water depths of less than 600 m, and in rough weather conditions less than 400 m. The EM710 operates at sonar frequencies of 70 to 100 kHz. Three sectors divide the transmit fan, where distinct frequencies or waveforms are transmitted sequentially. The swath width can reach 5.5 times the water depth. 256 beams with an acoustical 1°(TX)/1°(RX) footprint are formed for each ping. The transmit fan is electronically stabilized for roll, pitch and yaw. Combining phase and amplitude bottom detection algorithms allows achieving best possible accuracy. For further information, consult: https://epic.awi.de/id/eprint/26726/1/Kon2007b.pdf. 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 known for each beam and taking ray bending due to refraction in the water column by sound speed into account. During the M84/4 cruise, the EM710 was running in a 24-hour watch mode, in addition to the EM122 and the PARASOUND sub-bottom profiling system. Acquisition of EM710 data was reliable during the whole cruise; however, problems occurred during rough weather conditions, since the EM710 lost the bottom signal in depths of more than 400 m.
Responsible person during this cruise / PI: Tilmann Schwenk (tschwenk@marum.de)
Chief Scientist: Till J. J. Hanebuth (thanebuth@coastal.edu)
CR: https://www.tib.eu/de/suchen/id/awi%3Adoi~10.2312%252Fcr_m84_4/
CSR: https://www.ldf.uni-hamburg.de/meteor/wochenberichte/wochenberichte-meteor/m84/m84-4-scr.pdf
Keywords:
Bathymetry; Center for Marine Environmental Sciences; CT; EM710; File format; File name; File size; Galician Shelf; hydroacoustics; M84/4; M84/4-track; MARUM; Meteor (1986); Northeast Atlantic; Seismic; Underway cruise track measurements; Uniform resource locator/link to file
Type:
Dataset
Format:
text/tab-separated-values, 3192 data points
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