TAN2021_V01 Macquarie Ridge Complex 5m - 210m Multi-resolution AusSeabed products

Brief description

This layer group describes multibeam echosounder data collected on RV Tangaroa TAN2021_V01 titled "NIWA TAN2113", which was carried out on a contract to the CSIRO MNF. The voyage took place between November 9 and December 4, 2021 departing from Wellington (NZ) and arriving in Wellington (NZ).

The purpose of the voyage was to recover Ocean-bottom seismometers deployed by the RV Investigator in 2020 (IN2020_V06) and acquire MBES and SBP data in the Macquarie Island region.

This dataset is published with the permission of CSIRO. Not to be used for navigational purposes.

The dataset contains bathymetry grids of 5m to 210m resolution of the Macquarie Island Ridge Complex, produced from the processed EM302 and EM2040 bathymetry data.

Lineage

Raw data (*.all files) from the EM302 and EM2040 were processed using QPS Qimera v2.4.2 for
bathymetry and QPS GeoCoder Toolbox (FMGT) v7.10.0 for acoustic seafloor backscatter.
Qimera generates *.qpd files from all survey *.all files, which include all edits made to the raw files.
The quality of bathymetry data was examined, and surfaces of varying resolution generated for each
survey area. The data were cleaned in both 2D and 3D manually, removing erroneous pings, gross
errors, and obvious noise. For areas of consistently flat seafloor, a Medium Spline filter was used to
automatically remove erroneous pings. These areas were checked by the multibeam operators to
ensure no misclassification of good pings.
Gridded bathymetric surfaces were projected in WGS84 / UTM zone 57S (EPSG:32757) coordinate
reference system at varying resolutions during the voyage to aid further line planning and survey
priorities. Bathymetry datasets were collated, and maps produced in ArcGIS Pro v2.8.3.
Both MBES systems also record the acoustic returns of mid-water reflectors. Water column data
from both EM302 and EM2040 systems were logged (as *.wcd files). These files were not processed
on-board.
The raw files were analysed for noise and cleaned manually. The data was gridded at multiple resolutions in python Caris batch script using a Depth filter Vs Resolution guideline derived from AusSeabed Multibeam guidelines v2 and further inspected for outliers. Final raster products are available in L3 folder of this collection. Final processed data were also exported per line as GSF and ASCII format and available in the L2 folder of this collection.