This record describes multibeam echosounder data collected on the RV Investigator voyage IN2023_V04, International nutrient inter-comparison Voyage (INIV) which departed Hobart on the 05/06/23 and returned to Hobart on the 18/06/23. The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter in the Southern Ocean Southwest 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 799 files totalling 47.1 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 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 IN2024_E01, 'Trials and Calibrations' which departed Hobart on the 28th October and returned to Hobart on the 6th November 2024. The Kongsberg EM2040-MKII multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter. NOTE: The system was newly installed in Singapore as part of the vessel's mid-life refit and this voyage constituted the formal Sea Acceptance Test (SAT) for the system. The EM2040 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. Data are stored in .kmall raw format for bathymetry and backscatter and .kmwcd format for watercolumn backscatter at CSIRO. There are 135 files totalling 14.9 GB of raw data and 135 files totalling 287 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 IN2024_E01, 'Trials and Calibrations' which departed Hobart 28th October and returned to Hobart on the 6th November 2024. The Kongsberg EM712 multibeam echosounder was used to acquire seafloor bathymetry and backscatter information and watercolumn backscatter. NOTE: The system was newly installed in Singapore as part of the vessel's mid-life refit and this voyage constituted the formal Sea Acceptance Test for the system. 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 127 files totalling 24.8 GB of raw data and 127 files totalling 107 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 IN2024_E01, 'Trials and Calibrations' which departed Hobart on the 28th October and returned to Hobart on the 6th November 2024. The Kongsberg EM124 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter. NOTE: The system was newly installed in Singapore as part of the vessel's mid-life refit and this voyage constituted the formal Sea Acceptance Test for the system. 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 130 files totalling 6.31 GB of raw data and 131 files totalling 12.5 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 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 IN2019_V07, 'RAN Hydrographic and Maritime Heritage Surveys' which departed Hobart on the 11 April 2019 and returned to Hobart on the 23 April 2019. The Kongsberg EM710 MKII multibeam echosounder was used to acquire seafloor bathymetry and backscatter information [and watercolumn backscatter] along the Tasmanian East coast and in the central to eastern region of Bass Strait. 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 337 files totalling 67 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 applied to some of the processed data (i.e. AHO mapping area - files 0037 to 0112, and to other mapping sites - files 0188 to 0256). GPS tides (and reduction to AHD using AusGeoid 09) was applied to the BMR mapping areas (files 0257 to 0281, 0290 to 0293 & 0295 to 0300). 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 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 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 IN2017_C02, ['Hogan Group Hydrographic Survey – Bass Strait'] which departed Hobart on the 4th May 2017 and came alongside Bell Bay following completion of the survey on the 14th May 2017. The Kongsberg EM710 MKII multibeam echosounder was used to acquire seafloor bathymetry and backscatter information [and watercolumn backscatter] around Bass Strait. 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 465 files totalling 156 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 applied to the processed data using AusTides 2017. Processed data has had outliers removed. Processed line data are not available in *.gsf and ascii format, but can be requested. 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_C02, ['Hogan Group Hydrographic Survey – Bass Strait'] which departed Hobart on the 4th May 2017 and came alongside Bell Bay following completion of the survey on the 14th May 2017. The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information [and watercolumn backscatter] around Bass Strait. 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 236 files totalling 9.5 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 applied to the processed data. Processed data had outliers removed. Processed line data are not available in *.gsf and ascii format, however can be requested if required. 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.