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author Kopte, Robert
Miramontes, Elda
Schwenk, Tilmann
author_facet Kopte, Robert
Miramontes, Elda
Schwenk, Tilmann
collection Datos científicos de ciencias marinas y ambientales
contents Current velocities of the upper water column along the cruise track of R/V Sonne cruise SO304 were collected by a vessel-mounted 75 kHz RDI Ocean Surveyor ADCP. The ADCP transducer was located at 6.0 m below the water line. The instrument was operated in narrowband mode (WM10) with a bin size of 8.00 m, a blanking distance of 8.00 m, and a total of 100 bins, covering the depth range between 22.0 m and 814.0 m. Attitude data from the ship's motion reference unit were used by the data acquisition software VmDAS internally to convert ADCP beam velocities to geographic coordinates. The Python toolbox OSADCP (version 2.0.0) was used for data post-processing. Single-ping data were screened for bottom signals and, where appropriate, a bottom mask was manually processed. Acoustic Interferences were identified based on outliers in the ADCP echo intensity data. Echo intensity data were cleaned accordingly and affected velocity cells were flagged to be removed prior ensemble-averaging. The ship's velocity was calculated from position fixes obtained by the Global Navigation Satellite System (GNSS), taking into account lever arms of ADCP transducer and GNSS antenna. Accuracy of the derived water velocities mainly depends on the quality of the position fixes and the ship's heading data. Further errors stem from a misalignment of the transducer with the ship's centerline. Data processing included water track calibration of the misalignment angle (-0.0343° +/- 0.7392°) and scale factor (1.0001 +/- 0.0164) of the measured velocities. The velocity data were averaged in time using an average interval of 300 s. Depth cells with ensemble-averaged percent-good values below 50% are marked as 'bad data'.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_974242
institution PANGAEA
language en
publishDate 2024
publisher PANGAEA
record_format pangaea
spellingShingle Shipboard ADCP current measurements (75 kHz) during RV SONNE cruise SO304
Kopte, Robert
Miramontes, Elda
Schwenk, Tilmann
Backscatter, relative; BENGAL SHELF; Current velocity, east-west; Current velocity, north-south; DAM_Underway; DAM Underway Research Data; DataHub; DataHub Earth and Environment of the Helmholtz Association; DATE/TIME; DEPTH, water; Echo intensity; Echo intensity, cleaned; LATITUDE; LONGITUDE; Percent good pings; Pings, averaged to a double ensemble value; Quality flag, current velocity; Seadatanet flag: Data quality control procedures according to SeaDataNet (2010); SO304; SO304_0_Underway-5; Sonne_2; Vessel mounted Acoustic Doppler Current Profiler [75 kHz]; VMADCP-75
Current velocities of the upper water column along the cruise track of R/V Sonne cruise SO304 were collected by a vessel-mounted 75 kHz RDI Ocean Surveyor ADCP. The ADCP transducer was located at 6.0 m below the water line. The instrument was operated in narrowband mode (WM10) with a bin size of 8.00 m, a blanking distance of 8.00 m, and a total of 100 bins, covering the depth range between 22.0 m and 814.0 m. Attitude data from the ship's motion reference unit were used by the data acquisition software VmDAS internally to convert ADCP beam velocities to geographic coordinates. The Python toolbox OSADCP (version 2.0.0) was used for data post-processing. Single-ping data were screened for bottom signals and, where appropriate, a bottom mask was manually processed. Acoustic Interferences were identified based on outliers in the ADCP echo intensity data. Echo intensity data were cleaned accordingly and affected velocity cells were flagged to be removed prior ensemble-averaging. The ship's velocity was calculated from position fixes obtained by the Global Navigation Satellite System (GNSS), taking into account lever arms of ADCP transducer and GNSS antenna. Accuracy of the derived water velocities mainly depends on the quality of the position fixes and the ship's heading data. Further errors stem from a misalignment of the transducer with the ship's centerline. Data processing included water track calibration of the misalignment angle (-0.0343° +/- 0.7392°) and scale factor (1.0001 +/- 0.0164) of the measured velocities. The velocity data were averaged in time using an average interval of 300 s. Depth cells with ensemble-averaged percent-good values below 50% are marked as 'bad data'.
title Shipboard ADCP current measurements (75 kHz) during RV SONNE cruise SO304
topic Backscatter, relative; BENGAL SHELF; Current velocity, east-west; Current velocity, north-south; DAM_Underway; DAM Underway Research Data; DataHub; DataHub Earth and Environment of the Helmholtz Association; DATE/TIME; DEPTH, water; Echo intensity; Echo intensity, cleaned; LATITUDE; LONGITUDE; Percent good pings; Pings, averaged to a double ensemble value; Quality flag, current velocity; Seadatanet flag: Data quality control procedures according to SeaDataNet (2010); SO304; SO304_0_Underway-5; Sonne_2; Vessel mounted Acoustic Doppler Current Profiler [75 kHz]; VMADCP-75
url https://doi.org/10.1594/PANGAEA.974242