RV Investigator Voyage IN2021_V03 EM122 Multibeam Echosounder Data

This record describes multibeam echosounder data collected on RV Investigator voyage IN2021_v03, titled "Integrated Marine Observing System: monitoring of East Australian Current property transports at 27 degrees South (multi-year)." The voyage took place from Hobart (TAS) to Brisbane (QLD) between May 8 and June 3, 2021.

The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and water column backscatter, during the transit and at the East Australian Current (EAC) Moorings site.

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 (459 files 26.4 GB) and backscatter and *.wcd format for watercolumn backscatter (423 files 28.9 GB) at CSIRO.

Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.all format are corrected for motion and position. The data has been reduced to approximate Mean Sea Level (MSL) using the Earth Gravitation Model 2008 (EGM2008) 1 arc-minute x 1 arc-minute grid spacing.

Tide corrections were not applied to the processed data. Processed data had outliers removed. Processed line data are available in *.gsf (version 3.0.9) and ascii format, and processed bathymetry 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.