This record describes multibeam echosounder data collected on RV Investigator voyage IN2023_V01, titled "Antarctic Bottom Water Production in the past: Records from marine sediments, Cape Darnley, East Antarctica". The voyage took place between 25th January, 2023 and 2nd March, 2023 departing from Henderson's (WA) and arriving in Hobart (TAS). The Kongsberg EM710 MKII multibeam echosounder was used to acquire seafloor bathymetry and backscatter information and watercolumn backscatter between Fremantle to Antarctica and Albany to Hobart. 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 and .wcd format for watercolumn backscatter at CSIRO. There are 102 files totalling 26.3 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. Bathymetry data contained in .all format are corrected for motion and position. GPS tide was computed using the EGM2008 model and 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 multibeam echosounder data collected on RV Investigator voyage IN2023_V07, [FOCUS] which departed Hobart on the 15/11/23 and returned to Hobart on the 20/12/23. The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter around the Antarctic Circumpolar Current in the Southern Ocean, South of Hobart. 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 and .wcd format for watercolumn backscatter at CSIRO. There are 55 files totalling 14.2 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. GPS tide was computed using the EGM2008 model and applied to the processed data. Processed data has had outliers removed. Processed line data are available in .gsf and ascii format, and processed bathymetry 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 multibeam echosounder data collected on RV Investigator voyage IN2024_V01, 'Multidisciplinary Investigations of the Southern Ocean' which departed Hobart on 05/01/2024 and returned to Fremantle on 05/03/2024. The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter from Hobart, along the Antarctic ice edge to Fremantle. 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 1,199 files totalling 150.8 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. GPS tide was computed using the EGM2008 model and applied to the processed data. Processed data has had outliers removed. Processed line data are available in .gsf and ascii format, and processed bathymetry 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 multibeam echosounder data collected on RV Investigator voyage IN2023_V07, [FOCUS] which departed Hobart on the 15/11/23 and returned to Hobart on the 20/12/23. The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter around the Antarctic Circumpolar Current in the Southern Ocean, South of Hobart. 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 1834 files totalling 105 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. GPS tide was computed using the EGM2008 model and applied to the processed data. Processed data has had outliers removed. Processed line data are available in .gsf and ascii format, and processed bathymetry 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 multibeam echosounder data collected on RV Investigator voyage IN2016_E01, 'East Tasman Plateau – key to unravelling the onset of the Antarctic Circumpolar Current/MNF Equipment Sea Trials,' which departed Hobart on the 17 August 2016 and returned to Hobart on the 22 August 2016. The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry and backscatter information around the Cascade Seamount. 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 at CSIRO. There are 98 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 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 scientific split-beam echosounder data collected on the RV Investigator voyage IN2023_V01, titled "Antarctic Bottom Water Production in the past: Records from marine sediments, Cape Darnley, East Antarctica". The voyage took place between 25th January, 2023 and 2nd March, 2023 departing from Henderson's (WA) and arriving in Hobart (TAS). The Simrad EK60 split beam echosounders for18kHz and Simrad EK80 split beam echosounders for 38, 70 120, 200 and 333 kHz were used to acquire acoustic backscatter data to a range of 1,500m, between Fremantle and Antarctica (one-way) and then from Albany to Hobart. All frequencies were logged continuously for the extent of the voyage. The 75kHz and 120kHz frequencies were set to passive for shallow areas where EM710 was used. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 1,143 lines totalling 106 GB of raw data in this dataset. No post 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 multibeam echosounder data collected on RV Investigator voyage IN2016_E01, 'East Tasman Plateau – key to unravelling the onset of the Antarctic Circumpolar Current/MNF Equipment Sea Trials,' which departed Hobart on the 17 August 2016 and returned to Hobart on the 22 August 2016. The Kongsberg EM710 MKII multibeam echosounder was used to acquire seafloor bathymetry and backscatter information between Hobart and the Cascade Seamount. 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 26 files totalling 1.24 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 multibeam echosounder data collected on RV Investigator voyage IN2017_V01, 'Interactions of the Totten Glacier with the Southern Ocean through multiple cycles. ‘Sabrina Seafloor Survey' which departed Hobart on the 14th January 2017 and returned to Hobart on the 5th March 2017. The Kongsberg EM710 MKII multibeam echosounder was used to acquire seafloor bathymetry and backscatter information between Hobart and Totten Glacier. 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 and .wcd format for watercolumn backscatter at CSIRO. There are 71 files totalling 12 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 multibeam echosounder data collected on RV Investigator voyage IN2017_V01, 'Interactions of the Totten Glacier with the Southern Ocean through multiple cycles. ‘Sabrina Seafloor Survey' which departed Hobart on the 14th January 2017 and returned to Hobart on the 5th March 2017. The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information between Hobart and Totten Glacier. 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 1310 files totalling 32.9 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 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 multibeam echosounder data collected on RV Investigator voyage IN2015_E01, which departed Hobart on the 29 Jan 2015 and returned to Hobart on the 19 Feb 2015, after successfully testing equipment at 65° south. The Kongsberg EM710 multibeam echosounder was used to acquire seafloor bathymetry and backscatter information between Hobart and Antarctic waters. Ping rate varied according to depth. Data are stored in *.all raw format at CSIRO Oceans and Atmosphere. There are 97 files totalling 16.2 GB of raw data in this dataset. Sound velocity profiles were applied to this data during data acquisition. Tide corrections were not applied to the processed data. Additional information regarding this dataset is contained in the GSM data acquisition and processing report. Additional data products available on request.