This record describes multibeam echosounder data collected on RV Investigator voyage IN2025_V02, ' SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania ' which departed Hobart on the 26th March and returned to Hobart on the 14th April 2025. The EM124 provides a 1 degree by 1 degree angular resolution. The echosounder's nominal frequency is 12 kHz. Data are stored in *.kmall raw format for bathymetry and backscatter and *.kmwcd format for watercolumn backscatter at CSIRO. There are 327 files totalling 26.1 GB of raw data and 319 files totalling 53.7 GB of watercolumn data in this dataset. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.kmall format are corrected for motion and position. GPS tide was computed using the EGM2008 model and applied to the processed data. Processed data has had outliers removed. Additional information regarding this dataset, including further information on processing streams, is contained in the GSM data acquisition and processing report.

This record describes sub bottom profiler data collected on RV Investigator voyage IN2025_V02, ' SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania ' which departed Hobart on the 26th March and returned to Hobart on the 14th April 2025. The Kongsberg SBP29 (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 to 9 kHz. The SBP29 was logged continuously for the extent of the voyage. Data are stored in *.raw (251 files 5.66 GB) raw and *.seg (250 files 5.63 GB) segy formats at CSIRO. The segy format data had a real time processing stream applied, which applies gain, a gain correction, and matched filter with replica shaping (for water depths typically >200m) or Bandpass filtering 2-9 kHz (in water depths typically <200 m). 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 multibeam echosounder data collected on RV Investigator voyage IN2025_V02, ' SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania ' which departed Hobart on the 26th March and returned to Hobart on the 14th April 2025. The Kongsberg EM712 multibeam echosounder was used to acquire seafloor bathymetry and backscatter information and watercolumn backscatter. The EM712 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 *.kmall raw format for bathymetry and backscatter and *.kmwcd format for watercolumn backscatter at CSIRO. There are 13 files totalling 2.76 GB of raw data and 13 files totalling 11.7 GB of watercolumn data in this dataset. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.kmall format are corrected for motion and position. GPS tide was computed using the EGM2008 model and applied to the processed data. Processed data has had outliers removed. Additional information regarding this dataset, including further information on processing streams, is contained in the GSM data acquisition and processing report.

This record describes multibeam echosounder data collected on RV Investigator voyage IN2025_V02, ' SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania ' which departed Hobart on the 26th March and returned to Hobart on the 14th April 2025. The EM2040 MKII provides a 0.4 degree by 0.7 degree angular resolution. The echosounder's nominal frequency is 400 kHz (with a range of 200-700 kHz) and it operated in dual swath mode. This system was only operated in water depths typically shallower than 250 m. Data are stored in *.kmall raw format for bathymetry and backscatter and *.kmwcd format for watercolumn backscatter at CSIRO. There are 31 files totalling 6.88 GB of raw data and 31 files totalling 69.1 GB of watercolumn data in this dataset. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.kmall format are corrected for motion and position. GPS tide was computed using the EGM2008 model and applied to the processed data. Processed data has had outliers removed. Additional information regarding this dataset, including further information on processing streams, is contained in the GSM data acquisition and processing report.

This record describes magnetometer data collected on RV Investigator voyage IN2025_V02, ' SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania ' which departed Hobart on the 26th March and returned to Hobart on the 14th April 2025. The SeaSPY2 magnetometer uses an omnidirectional Overhauser sensor that requires no realignment or recalibration and has no heading error. The instrument has an absolute accuracy of 0.1 nT, sensor sensitivity of 0.01 nT and resolution of 0.001 nT. Data are stored in .CSV and .MMS data files at CSIRO. 29.69 MB of raw data was acquired in this dataset. No processing has been conducted on this data. The magnetometer was towed 300 m astern of the ship and a layback value of 361 m was applied to the magnetometer data. This was the total distance behind the ship's positioning reference point. Additional information regarding this dataset is contained in the GSM data acquisition and processing report.

This record describes gravity data collected on RV Investigator voyage IN2025_V02, ' SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania ' which departed Hobart on the 26th March and returned to Hobart on the 14th April 2025. The gravity meter instrument is a MicroG Lacoste Air-Sea II. Data are stored in .ENV and .DAT data files at CSIRO. There are 19 files totalling 262 MB of raw data in this dataset. Wharf ties were undertaken at PW4 in Hobart using a Scintrex Autograv CG-5. Wharf tie data can be found in: Gravity Tie_in2025v02_Hobart_SOV_20250325.TXT and Gravity Tie_in2025v02_Hobart_EOV_20250414.TXT, which is stored with the raw data. 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 XBT data collected on RV Investigator voyage IN2025_V02, ' SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania ' which departed Hobart on the 26th March and returned to Hobart on the 14th April 2025. A total of 3 XBT casts were conducted over the duration of 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 IN2025_V02, ' SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania ' which departed Hobart on the 26th March and returned to Hobart on the 14th April 2025. The Simrad EK80 split beam echosounders for 18, 38, 70 120, 200 were used to acquire acoustic backscatter data to a range of 1500 m. All of these frequencies were logged continuously for the extent of the voyage with the exception of periods of mooring triangulations. The 333 kHz was set to passive for the duration of the voyage due to a known issue with the transducer. Data are stored in *.raw, *.bot and *.idx format at CSIRO. There are 807 files totalling 76 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 Hydrology (HYD) data collected from the Marine National Facility (MNF) RV Investigator voyage IN2025_V02, titled: "Multiyear: Integrated Marine Observing System (IMOS) Southern Ocean Time Series (SOTS) Strategic Partnership." The voyage took place between March 26, 2025 and April 14, 2025 (AEST), departing from Hobart and returning to Hobart. Water samples collected during the voyage were analysed in the ship’s hydrochemistry laboratory for nutrients, dissolved oxygen, and salinity. No significant sample collection, analysis, or data processing issues were encountered for reporting. Five nutrients were determined: silicate, phosphate, nitrate + nitrite, nitrite and ammonium using a Seal AA3 autoanalyser. Certified reference materials for nutrients in seawater (RMNS) were within certified expanded uncertainty. Missing and suspect hydrology samples are listed in Appendix, Missing or Suspect Nutrient Data. For more information please refer to the Data Processing Report linked below. This dataset has been processed (quality-controlled), and archived at the CSIRO National Collections and Marine Infrastructure (NCMI) 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 End of Voyage (EOV) data archive from the Marine National Facility (MNF) RV Investigator voyage IN2025_V02, titled "Multiyear: Integrated Marine Observing System (IMOS) Southern Ocean Time Series (SOTS) Strategic Partnership." The voyage took place between March 26, 2025 and April 14, 2025 (AEST), departing from Hobart and returning to Hobart. For further information please refer to the voyage documentation links. Instruments used and data collected include: Regular measurements: Acoustic Doppler Current Profiler (ADCP; 75, 150 KHz), CTD, Cloud Condensation Nuclei counter (CCN), Disdrometer, Expendable Bathythermographs (XBTs), Fisheries Echosounder (EK80), Gravimeter, Hydrochemistry, Lowered ADCP (LADCP), Radon sensor, Weather Radar, pCO2, Multibeam Echosounder (EM712, EM124, EM2040), Sub-bottom Profiler (SBP29), Infrared Sea Surface Temperature Autonomous Radiometer (ISAR), Ozone Sensor, Nephelometer, Atmospheric Temperature, Humidity, Pressure, Wind and Rain sensors, Photosynthetically Active Radiation (PAR) sensor, Precision Infrared Radiometer (PIR), Precision Spectral Pyranometer (PSP), GPS Positioning System, Doppler Velocity Log, Thermosalinographs (TSG), Fluorometer, Oxygen Optode. Voyage-specific measurements: Black Carbon sensor (Aethalometer), Cloud Radar (BASTA), Moorings, Triaxus, Mobility particle size spectrometer (MPSS), Deep Towed Camera (DTC), Video, Mini Micro-Pulse LIDAR (miniMPL), Micro Rain Radar (MRR), Radiosondes, Cloud and Aerosol Backscatter Lidar (RMAN), Stabilised Platform, Water Vapor Radiometer (WVR). The archive for the IN2025_V02 EOV raw data is curated by the CSIRO National Collections and Marine Infrastructure (NCMI) Information and Data Centre (IDC) in Hobart, with a permanent archive at the CSIRO Data Access Portal (https://data.csiro.au/), providing access to voyage participants and processors of the data collected on the voyage. All voyage documentation is available electronically to MNF support via the local network. Applications to access voyage documentation by non-CSIRO participants can be made via data-requests-hf@csiro.au All processed data from this voyage are made publicly available through the MNF Data Trawler (in the related links)