Conference papers

100/30 m-resolution bathymetry grids for the Northern Australia

Author: Beaman, R.J.

Year: 2018

Publication: 100/30 m-resolution bathymetry grids for the Northern Australia, AusSeabed Workshop 4, 03 July 2018. AusSeabed Working Group, Adelaide, Australia.

Abstract

This seminar describes bathymetry (depth) products from the compilation of all available source bathymetry data within Northern Australia into 100 m- and 30 m-resolution Digital Elevation Models (DEMs). The Northern Australia region includes a broad continental shelf over 400 km wide extending out from Western Australia and the Northern Territory, and stretching over a distance of ~1500 km. This region encompasses numerous shallow coral reefs including the offshore Sahul Banks, drowned ancient river valleys, broad inner-shelf banks and a rugged coastline. Bathymetry mapping of the seafloor is vital for the protection of Northern Australia, allowing for the safe navigation of shipping and improved environmental management.

Shallow- and deep-water multibeam surveys reveal the highly complex seafloor of the continental shelf and slope canyons draining into the Indian Ocean and Timor Sea. Extensive singlebeam echosounder surveys cover much of the Northern Australia shelf. Airborne LiDAR bathymetry survey data were acquired by the Australian Hydrographic Office over most of the Sahul Banks reefs, with some coverage gaps over offshore reefs supplemented by satellite derived bathymetry. Electronic Navigational Chart spot depths were very useful for providing general depths across the area. The Geoscience Australia-developed Intertidal Elevation Model DEM greatly improves the source data gap along Northern Australia’s vast intertidal zone.

All source bathymetry data were extensively edited as point clouds to remove noise, given a consistent WGS84 horizontal datum, and where possible, an approximate MSL vertical datum. These new bathymetry DEMs are a major improvement on previous bathymetry models for the Northern Australia region, and are recommended for environmental management, resource development and maritime boundary purposes.

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