This record describes multibeam echosounder data collected on RV Investigator voyage IN2023_T01, titled 'Transit + Opportunistic Mapping + XBT AutoLauncher'. The primary objective of voyage IN2023_T01 is the safe and timely transit of RV Investigator from Sydney to Hobart in preparation for future voyages leaving the port of Hobart. The transit is direct with no operational time available for science operations unless underway at full speed. Any available operational time to be spent on opportunistic seafloor mapping – while keeping Expected Time of Arrival in Hobart on track as the primary objective. The voyage took place between November 2, 2023 and November 5, 2023 (AEST), departing from Sydney and returning to Hobart.
The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter transiting between Sydney to 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 17 files totalling 1.04 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.
