This record describes scientific split-beam echosounder data collected on the RV Investigator voyage IN2018_V01, Detecting Southern Ocean change from repeat hydrography, deep Argo and trace element biogeochemistry & CAPRICORN which departed Hobart on the 11 January 2018 and returned to Hobart on the 22 February 2018. 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, between Hobart and 66°S. All frequencies were logged continuously for the extent of the voyage but no personnel were on board to monitor the acquisition. Data are stored in *.raw, *.bot and *.idx format at CSIRO. There are 1041 *.raw files totalling 94.8 GB of raw data in this dataset. Processing has been conducted on this data for the return transit from 66S to Hobart.

This record describes the Acoustic Doppler Current Profiler (ADCP) data collected from the Marine National Facility RV Investigator voyage IN2018_V01, titled: "Detecting Southern Ocean change from repeat hydrography, deep Argo and trace element biogeochemistry & CAPRICORN." The voyage took place between the January 11 and February 22, 2018 departing Hobart (TAS) and returning to Hobart. Only the RDI Ocean Surveyor 75kHz ADCP was operational during this voyage. The RDI Ocean Surveyor 150kHz ADCP was not operated due to a hardware fault, so all data was collected with the RDI Ocean Surveyor 75kHz ADCP, which was run in narrow band mode only. The first four days of the voyage had a degraded seapath data feed to UHDAS. It appeared that the seapath D-GPS had been working in GNSS mode and not DGNSS. These issues were addressed by a reconfiguration of UHDAS to get a better heading calibration for the first part of the voyage and a subsequent part2 of the voyage was created. Internal triggering was used as the focus of this voyage was to collect current data and external triggering was found to be unstable on previous voyages. Port drop keel was flush with gondola for the majority of the voyage at 2m in the period between 2018-01-11T21:00:20Z and 2018-02-21T20:55:30Z. 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 Hydrology (HYD) data collected collected from the Marine National Facility RV Investigator Voyage IN2018_V01, titled: "Detecting Southern Ocean change from repeat hydrography, deep Argo and trace element biogeochemistry & CAPRICORN." The voyage took place between January 11 and February 21, 2018 departing from Hobart (TAS) and arriving in Hobart. Five nutrients were analysed; silicate, phosphate, nitrate + nitrite, nitrite and ammonium. This was the first time ammonium has been measured successfully on every station for a hydrographic voyage. High quality data was produced for the three measured parameters. Certified reference materials for nutrients in seawater were within the specified limits of the certified value. 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 Conductivity-Temperature-Depth (CTD) data collected from the Marine National Facility RV Investigator voyage IN2018_V01 titled: "Detecting Southern Ocean change from repeat hydrography, deep Argo and trace element biogeochemistry & CAPRICORN." The voyage took place from Hobart (TAS) to Hobart between January 10 and February 21, 2018. Data for 108 deployments were acquired using the Seabird SBE911 CTD 24, fitted with 36 twelve litre bottles on the rosette sampler. Seabird-supplied calibration factors were used to compute the pressures and preliminary conductivity values. Seabird/CSIRO-supplied calibrations were applied to the temperature data. The data were subjected to automated QC to remove spikes and out-of-range values. The final conductivity calibration was based on a single deployment grouping. The final calibration from the primary sensor for deployments 14-108 had a standard deviation (SD) of 0.0012686 PSU, well within our target of ‘better than 0.002 PSU’. The standard product of 1 dbar binned averaged netCDF files were produced using data from the primary sensors. The dissolved oxygen data calibration fit for deployments 14-108 had a SD of 0.78897 µM and 0.78113 µM for the primary and secondary sensors respectively. The agreement between the CTD and bottle data was good. Altimeters (200m and 500m), Transmissometer, PAR, ECO Chlorophyll and ECO OBS (Optical Back-Scatter) sensors were also installed on the auxiliary A/D channels of the CTD. 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 the Underway (UWY) data collected from the Marine National Facility (MNF) RV Investigator Voyage IN2018_V01, titled: "Detecting Southern Ocean change from repeat hydrography, deep Argo and trace element biogeochemistry & CAPRICORN." The voyage took place between January 11 and February 21, 2018 departing from Hobart (TAS) and arriving in Hobart. Standard Underway data is continuously recorded, consisting of: (1) Navigation data (NAV): Latitude, Longitude, Speed, Heading, Course Over Ground, Gyros, and Doppler Log (dual GPS instrument). (2) Thermosalinograph (TSG): Water Salinity, Flow-Rate, Temperature, Fluorescence, pCO2, Optode temperature and Oxygen. (3) Atmospheric (MET): Humidity, Wind Speed and Direction (vane and ultrasonic), Radiometer/Sea Surface Temperature, Pyranometer/Solar Radiation, Photosynthetically Active Radiation (PAR), Air Temperature, Air Pressure, Rain, Ozone and Trace Gases (port and starboard instruments). Data are recorded at 5 second intervals. Near real-time data are available via the link "Visualisation tool for Underway Data." This dataset has been processed and archived within the CSIRO Oceans & Atmosphere (O&A) Information and Data Centre (IDC) in Hobart (TAS). Data are available at time intervals of 5 sec (NetCDF format), 10 sec and 5 min (csv format). Additional information regarding this dataset is contained in the Voyage Summary and/or the Data Processing Report for this voyage.

This record describes the ISAR/SST Sea Surface Temperature data collected on the RV Investigator Voyages from 2014 onwards. The infrared SST autonomous radiometer (ISAR) is a self-calibrating instrument capable of measuring in situ sea surface skin temperature to an accuracy of 0.1 K. The SST Radiometer is mounted on the port bridge wing, approximately 19.593m above the summer load line. The RV Investigator ISAR skin SST data are also supplied both in real-time (http://thredds.aodn.org.au/thredds/catalog/IMOS/SOOP/SOOP-ASF/VLMJ_Investigator/meteorological_sst_observations/catalog.html) and in delayed mode after reprocessing (e.g., http://thredds.aodn.org.au/thredds/catalog/IMOS/SOOP/SOOP-ASF/VLMJ_Investigator/meteorological_sst_observations/2016/ISAR-QC/catalog.html). These reprocessed files will be particularly valuable for satellite SST validation (as the ISAR measures SST at the same depth as measured by satellites) and are currently (2017) being used by EUMETSAT for Sentinel-3 SST validation and to JMA and Oceans University China for Himawari-8 SST validation. Further information can be found in the data and documentation links below.

This record describes the End of Voyage (EOV) archive from the Marine National Facility (MNF) RV Investigator research voyage in2018_v01, titled "Detecting Southern Ocean change from repeat hydrography, deep Argo and trace element biogeochemistry & CAPRICORN." The voyage took place from Hobart (TAS) to Hobart between January 11 and February 22, 2018. There were two science projects in this voyage: 1) Detecting Southern Ocean change from repeat hydrography, deep Argo and trace element biogeochemistry 2) CAPRICORN (Clouds, Aerosols, Precipitation, Radiation, and Atmospheric Composition over the Southern Ocean). For further information refer to the Voyage documentation links below. Instruments used and data collected include: Regular measurements: Acoustic Doppler Current Profiler (ADCP; 75, 150 KHz ), Lowered ADCP (LADCP), Fisheries echosounder (EK60), GPS Positioning System, Doppler Velocity Log, Met station (temp, humidity, pressure, wind, rain, PIR, PSP, PAR), pCO2, Starboard and Portside Radiometers, Radon and Ozone sensors, Weather Radar, Greenhouse Gas Analysers (Aerodyne, Picarro), Air Pressure, Wind Speed and Direction sensors, Photosynthetically Active Radiation (PAR) sensor, Seawater (TSG, fluorometer, optode), Thermosalinographs, CTD, Hydrochemistry. Voyage-specific measurements: Aerosol Aerodynamic Particle sizer (APS), Aerosol Chemical Speciation Monitor (ACSM), Argo floats, Carbon, Chemical Ionisation Mass Spectrometer (CIMS), Chlorofluorocarbons/Sulfur Hexafluoride/Nitrogen Oxides (CFC SF6 Nox), Condensation Particle Counters (CPC), Cloud Condensation Nuclei counter (CCN), Continuous Plankton Recorder (CPR), Dissolved Inorganic Carbon (DIC), Disdrometer, Infrared Sea Surface Temperature Autonomous Radiometer (ISAR), Micro Rain Radar (MRR), Microwave Radiometer (MWR), Multiangle Absorption Photometer (MAAP), Nephelometer, Nutrient (NOx) autoanalyser, Proton-Transfer-Reaction Mass Spectrometry (PTR-MS), Radiosondes, Scanning Mobility Particle Sizers (SMPS), Sea-ice, Sonic Anemometer. The archive for the IN2018_V01 EOV raw data is curated by the CSIRO Oceans and Atmosphere (O&A) Information and Data Centre (IDC) in Hobart, with a permanent archive at the CSIRO Data Access Portal (DAP, https://data.csiro.au/dap/), providing access to participants and processors of the data collected in the voyage. All voyage documentation is available electronically to MNF support via the local network. Access to voyage documentation for non-CSIRO participants can be made via DataLibrariansOAMNF@csiro.au.