DOI: 10.5281/zenodo.14981745
title: Dissipation measurements from a Slocum Glider in the Southern Ocean during austral summer 2017, 2018 and 2019.

description: This dataset includes data from three Slocum/Microrider missions in the Southern Ocean occurring between 2017 and 2020.

Ocean microstructure measurements were obtained from a Rockland Scientific (RSI) MicroRider attached to an electric Slocum glider (Teledyne Webb Research, SN461).  Data were collected during three consecutive SANAE (South African National Antarctic Expeditions) resupply voyages aboard the RV SA Agulhas II. The data was collected in austral summers of 2017, 2018 and 2019 in the Subantarctic Zone (42°S, 7°E), the Antarctic Polar Frontal Zone (54°S, 0°E) and the Seasonal Ice Zone (60°S, 0°E) respectively.

In addition to the turbulence package, the glider was equipped with a pumped Seabird conductivity-temperature (CTD) sensor, a Wetlab ECO-puck (fluorescence and particulate backscatter), and an Anderaa oxygen optode. Note that oxygen data is not provided with this dataset.

During the first mission (Subantarctic Zone), the Slocum was configured to sample in a mooring mode, diving to 1000m. The microrider was initially configured (from 21-27 December 2017) to sample during both climbs and dives to 1000m. After that the glider transected northwards and the MR was not powered. From 4-16 January 2018 the MR was powered again and sampled during both climbs and dives to 500m.

During the second mission (Antarctic Polar Frontal Zone), the Slocum was configured to sample in a bowtie (transects of ~20km), diving to 1000m. The microrider was configured to sample only during climbs from 500m to the surface from 19 December 2018 – 8 March 2019. A previous version of this data was published with the research article "Nicholson, SA., Whitt, D.B., Fer, I. et al. Storms drive outgassing of CO2 in the subpolar Southern Ocean. Nat Commun 13, 158 (2022). https://doi.org/10.1038/s41467-021-27780-w".

During the third mission (Seasonal Ice Zone), from 17 December – 20 February (note that the MR stopped recording on the 2 February and the CT-pump failed on 23 January), the Slocum initially transected south from 58° S and once it arrived at 60°S, was again configured to sample in a bowtie (transects of ~20km), diving to 1000m. A previous version of this data was published with the research article "Giddy, I. S., I. Fer, S. Swart, and S. Nicholson, 2023: Vertical Convergence of Turbulent and Double-Diffusive Heat Flux Drives Warming and Erosion of Antarctic Winter Water in Summer. J. Phys. Oceanogr., 53, 1941–1958, https://doi.org/10.1175/JPO-D-22-0259.1."

Two separate NC files with all dissipation rate (and other related parameters) profiles and 1-s averaged sensor data, including flight parameters, collated into one file each per mission are provided. For more detailed information, please refer to the comments within each data file and the summary document. Individual profiles organized in four hierarchical groups including continuous time series of data converted into physical units, cleaned time series used for spectral analysis, wavenumber spectra, and dissipation rate estimates are available on request (SNicholson@csir.co.za).