RV Investigator Voyage IN2025_V04 EM712 Multibeam Echosounder Data

This record describes multibeam echosounder data collected on RV Investigator voyage IN2025_V04, titled "Untangling the causes of change over 25 years in the southeast marine ecosystem - Voyage IV." The voyage took place between May 27, 2025 and June 28, 2025 (AEST), departing from Hobart and returning to Hobart.The Kongsberg EM712 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter between Hobart and Eden.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 1188 files totalling 255 GB of raw data and 1183 files totalling 1.32 TB 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.