Ashmore Reef and Cartier Island Marine Parks Satellite-Derived Bathymetry Acquisition (20220016S)

The Ashmore Reef and Cartier Island Marine Parks Bathymetry was derived by EOMAP form multispectral satellite data from WorldView-3 satellite sensor. This was acquired by the Australian Government as part of the Marine Parks Grant - Round 3, in 2022-2023 and undertaken by EOMAP Australia Pty Ltd and EOMAP GmbH & Co.KG. The survey area encompasses the Ashmore Reef and Cartier Island Marine Parks in Western Australia. These critical geospatial data layers provide the essential environmental baseline information for the long-term monitoring and management of these Marine Parks. Mapping the shallow water zone is of importance both from an environmental and socioeconomic perspective. Having access to digital, georeferenced, high-resolution maps of bathymetry and benthic habitats of shallow water areas, is of fundamental use in the areas of navigation, ecological research, environmental modelling, management and conservation, and monitoring the impacts from climate change. Bathymetry data was processed using the physics-based inversion method to derive quantitative information of the shallow water bathymetry using the reflected sunlight energy in different wavelengths of the visible and near infrared region. This dataset is not to be used for navigational purposes. This dataset is published with the permission of the CEO, Geoscience Australia.

AusSeabed follows the recommended processing methodology as prescribed by the AusSeabed Multibeam Guidelines. Please note that certain products are subject to routine update (e.g. resolution, coverage, temporal variation, guidelines/best practice). The client is advised to refer to the latest version of all documents and products for the most up-to-date material. For eCat records the version is expressed in the record title whilst products incorporate date of production as per AusSeabed’s file naming convention.

The Kimberley Region and WA Reefs survey was acquired by the Australian Government. EOMAP was contracted by Geoscience Australia (GA) to provide high-resolution (10m) Satellite-Derived Bathymetry (SDB) for the Priority Australian Seabed Mapping Sites.

 

Survey metadata:

The satellite-derived bathymetry (SDB) was acquired by the following survey:

- Survey Name: EOMAP_20220513.1014 Ashmore Reef and Cartier Island Marine Parks Satellite-Derived Bathymetry Acquisition (20220016S)

- Vessel Name: Satellite

- Institution: EOMAP Australia Pty Ltd

- Country: Australia

- Operator: Maxar

- Sensor: WorldView-3

- Start Date: 24/05/2017

- End Date: 01/09/2022

- Start Port: Ashmore Reef; Cartier Island

- End Port: Ashmore Reef; Cartier Island

- Grid resolution: 2m

- Number of grids: 2

- Use Limitation: This dataset is not to be used for navigational purposes.

- This dataset is published with the permission of the CEO, Geoscience Australia

- Vertical Datum: EGM2008

- Horizontal Datum: WGS84/UTM51S (EPSG:32751)

Processing methodology:

The data provides bathymetric information based on optical satellite image data. Data were processed by the Modular and Inversion System (MIP) by EOMAP GmbH & Co.KG. The MIP is designed for the physically based assessment of hydro-biological parameters from multi- and hyperspectral remote sensing data. Supplemental Information: EOMAPs Satellite Derived Bathymetry (SDB) method relies on the reflected light energy which is measured at the satellite sensor in space. In order to measure the water column thickness, the sea bottom reflection must be separated from all other simultaneously measured portions of light. Other contributors of light scattered to the sensor are atmospheric molecules and aerosols, adjacent scattering from land, the water surface reflection, and light scattered and absorbed due to particular properties of water constituents and the pure water itself. The pure water itself also absorbs light in a spectrally specific manner and therefore leaves unique signatures in the signal while the light passes through the water column and returns after reflection at the sea bottom. This property is relevant to estimate water depth from optical satellite imagery. As many properties can vary over space and time, effective correction, regularisation and retrieval algorithms must be applied to avoid unstable results. EOMAP developed and maintains these unique algorithm and its workflows for almost two decades. The maximum depth the system is able to sense is related to the complex interaction of radiance of bottom material, incident sun angle and intensity, and the type and quantity of organics or sediments in the water column. As a rule-of-thumb, satellite-derived bathymetry should be capable of sensing bottom to depths equal to one to one point five times the Secchi depth.

Correction modules applied: Corrected for Satellite sensor noise: Yes, Corrected for atmospheric effects: Yes, Corrected for the effect of adjacent land reflectance: Yes, Corrected for effects of turbidity: Yes, Corrected for water refraction effect: No, Ground-control points accessed to improve horizontal accuracy: No, Local in-situ data accessed for calibration and validation purposes: No, Datum: Lowest Astronomical Tide based on Admirality Total Tide Station Ashmore Reef (West Inlet), 6274 (HAT: +4.3m above CD, MSL: +2.09m above CD, SATREC: +2.2m above CD, LAT: +0.1m above CD), Data type: 32bit Geotiff and ASCII xyz text file, Units: m NoDataValue: -9999

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At Geoscience Australia, the received geotiff was shifted to EGM2008 using AusCoastVDT and CARIS HIPS and SIPS. The final processed grids were exported as a 32-bit floating point Geotiff at 2m resolution, referenced to EGM2008.

DATA QUALITY

This dataset has been subject to independent post-production validation and testing. Tests have been performed for data completeness, correct spatial representation, attribute accuracy, logical consistency, metadata completeness and correctness, and where appropriate for compliance with Geoscience Australia's data dictionaries.

Errors found in this dataset should be reported to:

Corporate Data Manager

Geoscience Australia

GPO Box 378

Canberra ACT 2601, Australia

Email: Sales@ga.gov.au

Reported Errors will be rectified in subsequent data releases, if any.