RV Investigator Voyage IN2022_V08 EM122 Multibeam Echosounder Data

This record describes multibeam echosounder data collected on RV Investigator voyage IN2022_V08, titled "Biodiversity Assessment of Australia’s Indian Ocean Territories", which departed Darwin on September 30 and returned to Fremantle on November 3, 2022. This was a continuation of voyage IN2021_v04.

The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter between Darwin and Fremantle (via the Indian Ocean Territories).

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 1195 *.all files totaling 54 GB of raw bathymetry/backscatter data and 1195 *.wcd files totaling 73.7 GB of watercolumn 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 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.