This record describes multibeam echosounder data collected on RV Investigator voyage IN2018_V05, 'How does a standing meander southeast of Tasmania brake the Antarctic Circumpolar Current?' which departed Hobart on the 16th October 2018 and returned to Hobart on the 16th November 2018. The objectives of the voyage included: (1) Deployment of a fleet of EM-APEX profiling floats, (2) Deployment of a tall mooring at the crest of a meander in the Polar Front of the Antarctic Circumpolar Current, (3) Full-depth hydrographic survey of the physics and biogeochemistry of the targeted ACC meander, conducting transects across the front and (4) Triaxus transects across and along the front. The Kongsberg EM710 MKII multibeam echosounder was used to acquire seafloor bathymetry and backscatter information during the departing transit from Hobart to a depth of around 1,177 m (at a position of 43.95°S; 147.78°E). The EM710 MKII provides a 0.5° by 1° transmit and receive angular resolution respectively. The echosounder's nominal frequency range is from 40 to 100 kHz. Data are stored in *.all raw format for bathymetry and backscatter at CSIRO. There are 12 files totalling 3.42 GB of raw data in this dataset. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.all format are corrected for motion and position. Tide corrections were not applied to the processed data. Processed data has had outliers removed. Processed line data are available in *.gsf and ascii format, and processed bathymetry and backscatter grids in geotiff format. Additional information regarding this dataset, including further information on processing streams, is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes XBT data collected on RV Investigator voyage IN2018_V05, which departed Hobart on 16/10/2018, and arrived in Hobart on 16/11/2018. A total of 01 XBT casts were conducted over the duration of this voyage. The majority of T-S and speed of sound profiles were derived from 77 CTD casts that were undertaken during this voyage. Data are stored in netCDF files at CSIRO. Additional information regarding this dataset is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes scientific split-beam echosounder data collected on the RV Investigator voyage IN2018_V05, 'How does a standing meander southeast of Tasmania brake the Antarctic Circumpolar Current?' which departed Hobart on the 16th October 2018 and returned to Hobart on the 16th November 2018. The objectives of the voyage included: (1) Deployment of a fleet of EM-APEX profiling floats, (2) Deployment of a tall mooring at the crest of a meander in the Polar Front of the Antarctic Circumpolar Current, (3) Full-depth hydrographic survey of the physics and biogeochemistry of the targeted ACC meander, conducting transects across the front and (4) Triaxus transects across and along the front. The Simrad EK60 split beam echosounders 18, 38, 70 120, 200 and 333 kHz were used to acquire acoustic backscatter data to a range of 1500 m, from Hobart to Hobart. All frequencies were logged continuously (with the exception of occasional cessations required for acoustically quiet periods) for the extent of the voyage. The frequencies were set to passive during sensitive VMP deployment periods of the voyage in the ACC, when acoustic silent periods were requested by the science party. Data are stored in *.raw, *.bot and *.idx format at CSIRO. There are 1221 files totalling 105 GB of raw data in this dataset. No processing has been conducted on this data. Additional information regarding this dataset is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes sub bottom profiler data collected on RV Investigator voyage IN2018_V05, 'How does a standing meander southeast of Tasmania brake the Antarctic Circumpolar Current?' which departed Hobart on the 16th October 2018 and returned to Hobart on the 16th November 2018. The objectives of the voyage included: (1) Deployment of a fleet of EM-APEX profiling floats, (2) Deployment of a tall mooring at the crest of a meander in the Polar Front of the Antarctic Circumpolar Current, (3) Full-depth hydrographic survey of the physics and biogeochemistry of the targeted ACC meander, conducting transects across the front and (4) Triaxus transects across and along the front. The Kongsberg SBP120 (sub bottom profiler) was used to acquire data containing the specular reflections at different sediment interfaces below the seafloor. The SBP120 provides a 3° by 3° angular resolution. The echosounder's frequency sweep range is from 2.5 to 7 kHz. The SBP120 was logged for the extent of the voyage between Hobart and Hobart, but was set to passive mode during sensitive VMP deployment periods of the voyage in the ACC, when acoustic silent periods were requested by the science party. Data are stored in *.raw (297 files 5.67 GB) raw and *.seg (292 files 5.65 GB) segy formats at CSIRO. The segy format data had a real time processing stream applied, which applies gain, a gain correction, matched filter with replica shaping, an attribute calculation for instantaneous amplitude and time variable gain. Additional information regarding this dataset is contained in the GSM data acquisition and processing report. Additional data products may be available on request

This record describes gravity data collected on RV Investigator voyage IN2018_V05, 'How does a standing meander southeast of Tasmania brake the Antarctic Circumpolar Current?' which departed Hobart on the 16th October 2018 and returned to Hobart on the 16th November 2018. The objectives of the voyage included: (1) Deployment of a fleet of EM-APEX profiling floats, (2) Deployment of a tall mooring at the crest of a meander in the Polar Front of the Antarctic Circumpolar Current, (3) Full-depth hydrographic survey of the physics and biogeochemistry of the targeted ACC meander, conducting transects across the front and (4) Triaxus transects across and along the front. The gravity meter instrument is a MicroG Lacoste Air-Sea II. Data are stored in .ENV and .DAT data files at CSIRO. There are 64 files totalling 514 MB of raw data in this dataset. Wharf ties were not undertaken. Gravity data was acquired for the full duration of the voyage from Hobart to Hobart. No processing has been conducted on this data. Additional information regarding this dataset is contained in the GSM data acquisition and processing report.

This record describes multibeam echosounder data collected on RV Investigator voyage IN2018_V05, 'How does a standing meander southeast of Tasmania brake the Antarctic Circumpolar Current?' which departed Hobart on the 16th October 2018 and returned to Hobart on the 16th November 2018. The objectives of the voyage included: (1) Deployment of a fleet of EM-APEX profiling floats, (2) Deployment of a tall mooring at the crest of a meander in the Polar Front of the Antarctic Circumpolar Current, (3) Full-depth hydrographic survey of the physics and biogeochemistry of the targeted ACC meander, conducting transects across the front and (4) Triaxus transects across and along the front. The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter from Hobart to Hobart with particular emphasis on the scientific study area bounded between the following approximate coordinates: 54.156° to 57.344° (South) and 148.577° to 156.344° (East). The sonar was set to passive mode during sensitive VMP deployment periods of the voyage in the ACC, when acoustic silent periods were requested by the science party. The EM122 provides a 1 degree by 1 degree angular resolution. The echosounder's nominal frequency is 12 kHz. Data are stored in *.all raw format for bathymetry and backscatter and *.wcd format for watercolumn backscatter at CSIRO. There are 597 files totalling 18.6 GB of raw data in the dataset. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.all format are corrected for motion and position. Tide corrections were not applied to the processed data. Processed data had outliers removed. Processed line data are available in *.gsf and ascii format, and processed bathymetry and backscatter grids in geotiff format. Additional information regarding this dataset, including information on processing streams, is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes the Acoustic Doppler Current Profiler (ADCP) data collected from the Marine National Facility RV Investigator voyage IN2018_V05, titled: "How does a standing meander southeast of Tasmania brake the Antarctic Circumpolar Current?" The voyage took place from Hobart (TAS) to Hobart between October 16 and November 16, 2018. Data was collected during in2018_v05 for the duration of the voyage. Data was collected using UHDAS and post-processed using CODAS. Both the RDI Ocean Surveyor 150 kHz ADCP and the RDI Ocean Surveyor 75 kHz ADCP were run in narrow band. Internal triggering was used as external triggering was found to be unstable on previous voyages. The drop keel was at 6 m below the waterline for the duration of the voyage. See the voyage computing and electronics report for more details regarding data acquisition. This dataset was processed and then archived within the CSIRO Oceans and Atmosphere (O&A) Information and Data Centre (IDC) in Hobart.

This record describes the Conductivity-Temperature-Depth (CTD) data collected from the Marine National Facility RV Investigator voyage IN2018_V05, titled: "How does a standing meander south-east of Tasmania brake the Antarctic Circumpolar Current?" The voyage took place from Hobart (TAS) to Hobart between October 16 and November 16, 2018. Data for 77 deployments were acquired using the Seabird SBE911 CTD unit 24, fitted with 36 twelve litre bottles on the rosette sampler. Samples were collected on all casts. Sea-Bird-supplied and CSIRO calibration factors were used to compute the pressures and preliminary conductivity, oxygen and temperature data. Automated QC was applied to the data to remove spikes and out-of-range values. A Biospherical photosynthetically active radiation (PAR), Wetlabs transmissometer and Chelsea fluorometer were installed on the auxiliary A/D channels of the CTD. Two altimeters, a serial IMU and the LADCP unit was also attached to the rosette for all casts. A high resolution magnetometer/accelerometer to assist processing the LADCP data was attached to the frame, supplied by the University of Columbia, it was logging internally and the data downloaded to the ~\in2018_v05\science\CTD\Magnetometer folder in the voyage record. The collected data were subsequently processed and archived within the CSIRO Oceans and Atmosphere (O&A) Information and Data Centre (IDC) in Hobart. Additional information regarding this dataset may be contained in the Voyage Summary and the CTD Data Processing Report.

This record describes Hydrology (HYD) data collected from the Marine National Facility (MNF) RV Investigator voyage IN2018_V05, titled "How does a standing meander southeast of Tasmania brake the Antarctic Circumpolar Current?" The voyage took place from Hobart (TAS) to Hobart between October 16 and Novermber 16, 2018. Hydrology samples were collected from Niskin bottles sampled at various depths during Conductivity-Temperature-Depth (CTD) deployments. Parameters analysed were salinity, dissolved oxygen, phosphate, silicate, nitrate plus nitrite and ammonium. This dataset has been archived at the CSIRO O&A Information and Data Centre (IDC) in Hobart. Additional information regarding this dataset is contained in the Voyage Report and Data Processing Report.

This record describes the data (CTD, Dissolved Oxygen, Transmissometer, PAR, ECO Triplet, Nitrate, Fluorescence and LOPC) collected using the towed TRIAXUS platform on Investigator voyage IN2018_V05, titled: "How does a standing meander southeast of Tasmania brake the Antarctic Circumpolar Current?" The voyage took place from Hobart (TAS) to Hobart between October 16 and November 16, 2018. Data for 10 deployments were acquired using the Seabird SBE911 CTD 25 over 33 separate legs or sections. Sea-Bird-supplied calibration factors and CSIRO supplied calibrations were used to compute the pressures, conductivity and temperature data. The data were subjected to automated QC to remove spikes and out-of-range values. Dissolved oxygen sensors, a Transmissometer and a Cosine Photosynthetically Active Radiation (PAR) sensor were also installed on the auxiliary A/D channels of the CTD. In addition to the auxiliary channels, ECO Triplet, Nitrate, Fluorescence and LOPC were mounted on the Triaxus as attached payloads. The standard product of 1 decibar/10 second binned averaged were produced using data from the primary sensors to produce an along-track time-series dataset. Vertical casts with interpolated values from the along the track using this binned data was also produced with a search distance of 2 casts. This generated the vertical cast and along-track section data products for each Triaxus tow. The collected data were subsequently archived within the CSIRO Oceans and Atmosphere (O&A) Information and Data Centre (IDC) in Hobart. Additional information regarding this dataset may be contained in the Voyage Summary and the Data Processing Report.