Mentelle Basin Survey (GA-0293/SS08/2005) - Bathymetry grids

Brief description

The Mentelle Basin survey GA-0293, SS08/2005 was acquired by Geoscience Australia onboard the RV Southern Surveyor from the 28th of September to the 19th of October 2005. This deep water rift basin (up to 4500m depth) is located offshore from Fremantle on the SW Australian margin. The objectives of the survey was to study deep water marine habitats and to assess the petroleum potential of the Mentelle Basin. The swath data collected covered a new area of seabed that revealed the extents of the blind submarine canyons and completed the coverage of the Perth Canyon and filled the remaining gaps with high resolution swath bathymetry data.

This dataset is not to be used for navigational purposes.

Lineage

Maintenance and Update Frequency: asNeeded

Statement: The multibeam bathymetry was acquired by the following survey: - Survey Name: GA-0293 Mentelle Basin, SS08/2005 - Vessel Name: RV Southern Surveyor - Institution: Geoscience Australia -Country: Australia - Operator: CSIRO - Multibeam system: Kongsberg EM300 - Year of installation: 2004 - Nominal sonar frequency: 30 kHz - Number of beams: 135 beams - Beamwidth across track: 1 degree - Beamwidth alon track: 1 degree - Pulse length: variable -Selectable depth range: 10m - 5000m - Vessel speed: 7 - 8 knots - Start Date: 28/89/2005 - End Date: 19/10/2005 -Start Port: Fremantle -End Port: Fremantle The Mentelle Basin survey, GA-0293 SS08/2005 was acquired by Geoscience Australia onboard the RV Southern Surveyor from the 28th of September to the 19th of October 2005. The Chief scientist onboard was Dr. Andrew Heap. This dataset was acquired and processed onboard by Michele Spinoccia and further processing was conducted in the office by Michele Spinoccia, using CARIS HIPS & SIPS ver 7.1.2. 1. First a vessel configuration file was created where the co-ordinates of the motion sensor and DGPS antenna and patch test offsets were recorded. 2. A new project was then created and the vessel configuration file was attached to the project file. 3. The raw swath sonar data, in raw.all format, for each line was then imported into the project and the vessel information assigned to the data. 4. The motion sensor, DGPS and heading data were then cleaned using a filter that averaged adjacent data to remove artifacts. 5. Different sound velocity profiles data for each block were attached to the corresponding raw swath sonar data files to correct the depths for changes in the speed of sound through the water column. 6. Then a new blank field area was defined that specified the geographic area of study and the co-ordinate system used. The co-ordinates for the study areas were WGS84 UTM-50S. 7. The data was cleaned by applying several filters that removed any remaining spikes in the bathymetry data using user defined threshold values. A visual inspection of the data for each line was then undertaken where artifacts and noisy data not removed by the filtering process were removed manually using Swath and subset editors modules of the Caris HIPS/SIPS software. 8. All the data for each bathymetric, motion sensor, DGPS, heading, tide and sound velocity profile data were merged to produce the final processed data file. A weighted grid of the processed data was then created for each Block. In GA the tide was applied to the grid to correct for tidal variations and velocity corrections were performed to correct for different artifacts and mismatches. 9. The processed data was finally exported as grids soundings or false colored images for presentation and reporting and as final processed data in in ASCII XYZ as well as geotif formats of 50m resolution. 10- Using CARIS Base editor 4.0 the grids were exported as ESRI ASCII grid, then imported into ARC catalogue/info to create a raster file for the entire survey.