University of Bergen
Dissipation measurements from a Slocum glider at the Barents Sea Polar Front, October 2020.
Recommended citation:
Fer, Ilker; Kolås, Eivind; Elliott, Fiona
(2023)
Dissipation measurements from a Slocum glider at the Barents Sea Polar Front, October 2020.
https://doi.org/10.21335/NMDC-1033548414
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Abstract
Ocean microstructure measurements were obtained from a Rockland Scientific (RSI) MicroRider (MR) attached to an electric Slocum glider. The goal was to conduct ocean mixing and water transformation process studies in the Barents Sea Polar Front region east of Svalbard, in the northern Barents Sea. The glider was deployed on 8 October 2020 at 22:00 UTC and retrieved on the morning of 24 October. The MR stopped sampling on 15 October. During the mission, we obtained 130 files with data between consecutive surfacing of the glider, excluding files opened before deployment and after recovery of the glider and those when the test dives were made. Each of the 130 processed files is supplied as a NetCDF (NC) file with hierarchical groups. In total, there are 263 sections. A section (a more general term for a profile) is a continuous segment of the time series with dissipation estimates. One file can have multiple sections, for example, from the dive and climb parts of the time series. The converted data are prepared following the SCOR Working Group 160, ATOMIX guidelines and conventions (https://wiki.uib.no/atomix). In addition to the 130 NC files (one NC file per instrument's native file) compressed in one folder, we supply two separate NC files (MERGED_SLOW and MERGED_EPSI) with all dissipation rate (and other related parameters) profiles and 1-s averaged sensor data, including flight parameters, collated into one file each. Using the MERGED files, the user can bypass the download of full records from the individual NC files. Files per cast: DAT_022 to DAT_039.nc and DAT_041 to DAT_152.nc The NC files per instrument's native file include four hierarchical groups: L1_converted : time series from all sensors converted into physical units L2_cleaned : selected signals that are filtered and/or despiked before spectral analysis. Time stamp and length of the signals are the same as in L1. L3_spectra : wavenumber spectra from shear probes and vibration sensors L4_dissipation: dissipation estimates together with quality control parameters Detailed attributes and metadata are given at the global level as well as at the group level, including choices of processing parameters. For detailed information on the parameter names, description, and processing choices, the user is referred to https://wiki.uib.no/atomix. Dissipation estimates are from half-overlapping 5 s segments, using 2-s spectral calculations. The motivation for providing the full time-series data is that the user can reprocess it with their own routines if needed (either from the time series level or the spectra level). A user interested in 1-second time averaged slow sensor data and dissipation rate profiles may find the two merged NC files more practical and easily accessible. Data quality flags are provided for dissipation estimates (L4). A final dissipation estimate failing the data quality control is reported as not-a-number (NaN); however, the individual dissipation estimates from each probe are accessible in the L4 data.
Scientific keywords:
EARTH SCIENCE> OCEANS> MARINE GEOPHYSICS
Key words:
Barents Sea, polar front, glider, mixing, turbulence, dissipation rate, microstructure, shear probes