Description
Summary:Progress Code: completed Maintenance and Update Frequency: asNeeded Statement: Original field data. Processed data are SV corrected, tide not corrected and edited using CARIS version 10.3 This record describes multibeam echosounder data collected on RV Investigator voyage IN2018_V05, 'How does a standing meander southeast of Tasmania brake the Antarctic Circumpolar Current?' which departed Hobart on the 16th October 2018 and returned to Hobart on the 16th November 2018. The objectives of the voyage included: (1) Deployment of a fleet of EM-APEX profiling floats, (2) Deployment of a tall mooring at the crest of a meander in the Polar Front of the Antarctic Circumpolar Current, (3) Full-depth hydrographic survey of the physics and biogeochemistry of the targeted ACC meander, conducting transects across the front and (4) Triaxus transects across and along the front. The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter from Hobart to Hobart with particular emphasis on the scientific study area bounded between the following approximate coordinates: 54.156° to 57.344° (South) and 148.577° to 156.344° (East). The sonar was set to passive mode during sensitive VMP deployment periods of the voyage in the ACC, when acoustic silent periods were requested by the science party. 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 597 files totalling 18.6 GB of raw data in the 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 not 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. ...