This data represents the percentage of time the Shields parameter (Shields, 1936) exceeds 0.25. The Shields parameter (non-dimensional bed shear stress) value of 0.25 is assumed to be the threshold for creating disturbed patches on the seabed. This value is several times larger than that required to initiate traction bedload transport (~0.05) and falls in the middle of the ripple and dune bedform stability field. It represents conditions when the seabed is highly mobile and where patches of disturbed habitat are likely to be created. Shields, A. 1936. Application of similarity principles and turbulence research to bed-load movement. Mitteilunger der Preussischen Versuchsanstalt f¨ur Wasserbau und Schiffbau 26: 5-24

This data represents the average time between events when the Shields parameter (Shields, 1936) exceeds 0.25 based on a Peaks-Over-Thresholds (POT) analysis. The Shields parameter (non-dimensional bed shear stress) value of 0.25 is assumed to be the threshold for creating disturbed patches. This value is several times larger than that required to initiate traction bedload transport (~0.05) and falls in the middle of the ripple and dune bedform stability field. It represents conditions when the seabed is highly mobile and where patches of disturbed habitat are likely to be created. The unit for the dataset is day. Shields, A. 1936. Application of similarity principles and turbulence research to bed-load movement. Mitteilunger der Preussischen Versuchsanstalt f'ur Wasserbau und Schiffbau 26: 5-24

<b>This service with existing dataset is migrated to a new server and the existing links will expire by the end of this year (31-Dec-2024). The replacement service is located at https://services.ga.gov.au/gis/rest/services/DEM_SRTM_1Second_over_Bathymetry_Topography_2024/MapServer</b> The Australian Bathymetry and Topography web service includes the topography of Australia and the bathymetry of the adjoining Australian Exclusive Economic Zone. The area selected does not include data from Australia's marine jurisdiction offshore from the Territory of Heard and McDonald Islands and the Australian Antarctic Territory. The 2009 bathymetry data were compiled by Geoscience Australia from multibeam and single beam data, and along with the topography (onshore) data, was derived from multiple sources. As per the 2005 grid, the 0.0025 dd resolution is only supported where direct bathymetric observations are sufficiently dense (e.g. where swath bathymetry data or digitised chart data exist) (Webster and Petkovic, 2005). In areas where no sounding data are available (in waters off the Australian shelf), the grid is based on the 2 arc minute ETOPO (Smith and Sandwell, 1997) and 1 arc minute ETOPO (Amante and Eakins, 2008) satellite derived bathymetry. The topographic data (onshore data) is based on the revised Australian 0.0025dd topography grid (Geoscience Australia, 2008), the 0.0025dd New Zealand topography grid (Geographx, 2008) and the 90m SRTM DEM (Jarvis et al, 2008).

<b>This service with existing dataset is migrated to a new server and the existing links will expire by the end of this year (31-Dec-2024). The replacement service is located at https://services.ga.gov.au/gis/rest/services/DEM_SRTM_1Second_over_Bathymetry_Topography_2024/MapServer</b> The Australian Bathymetry and Topography web service includes the topography of Australia and the bathymetry of the adjoining Australian Exclusive Economic Zone. The area selected does not include data from Australia's marine jurisdiction offshore from the Territory of Heard and McDonald Islands and the Australian Antarctic Territory. The 2009 bathymetry data were compiled by Geoscience Australia from multibeam and single beam data, and along with the topography (onshore) data, was derived from multiple sources. As per the 2005 grid, the 0.0025 dd resolution is only supported where direct bathymetric observations are sufficiently dense (e.g. where swath bathymetry data or digitised chart data exist) (Webster and Petkovic, 2005). In areas where no sounding data are available (in waters off the Australian shelf), the grid is based on the 2 arc minute ETOPO (Smith and Sandwell, 1997) and 1 arc minute ETOPO (Amante and Eakins, 2008) satellite derived bathymetry. The topographic data (onshore data) is based on the revised Australian 0.0025dd topography grid (Geoscience Australia, 2008), the 0.0025dd New Zealand topography grid (Geographx, 2008) and the 90m SRTM DEM (Jarvis et al, 2008).

Australia’s marine jurisdiction covers over 10 million square kilometres, and we estimate that only 25% of its seafloor has been mapped to the adequate resolution required to support the sustainable development and management of our marine estate. Considering that seabed mapping underpins most aspects of ocean sciences and engineering, and contributes strongly to Australia’s economic, environmental and social values, it is critical that we address this fundamental knowledge gap. AusSeabed was founded three years ago—a cross sector collaborative national program aimed at coordinating ocean mapping efforts to maximise benefits to stakeholders. AusSeabed is working to address many challenges surrounding efficient data acquisition, quality assurance, processing and delivery to various end-users with an aim to eliminate duplication of effort and improve data quality and consistency across sectors. A fundamental component of the AusSeabed program is the design and development of a federated, cloud-based, open-source platform to address the whole supply chain from data acquisition to delivery. Importantly, this work is enabling seamless collation of seabed mapping datasets and their integration with other marine data types from a variety of previously isolated and inaccessible holdings. Strong community commitment and a powerful resonance with stakeholders have driven rapid program growth and are a testament to the value of deliberate and effective collaboration for national benefit. This presentation will give an overview of AusSeabed’s current progress, highlights and forward plan.

This data represents the integrated Shields (Shields, 1936) parameter exceeding 0.25 divided by the integrated total Shields parameter. The Shields parameter (non-dimensional bed shear stress) value of 0.25 is assumed to be the threshold for creating disturbed patches. This value is several times larger than that required to initiate traction bedload transport (~0.05) and falls in the middle of the ripple and dune bedform stability field. It represents conditions when the seabed is highly mobile and where patches of disturbed habitat are likely to be created. Shields, A. 1936. Application of similarity principles and turbulence research to bed-load movement. Mitteilunger der Preussischen Versuchsanstalt f¨ur Wasserbau und Schiffbau 26: 5-24

The Australian Submarine Canyons service identifies the location of 753 submarine canyons surrounding mainland Australia and its external territories, with associated metrics.

<div>Australia’s vast marine estate offers high-quality offshore wind resources that have the potential to help produce the renewable energy that Australia will need to achieve its net zero emissions targets. Mature offshore renewable industries in Europe have demonstrated that marine geoscience is critical for supporting the sustainable development, installation, operation and decommissioning of offshore wind farms. Geoscience information is used to design targeted seabed surveys and identify areas suitable for offshore infrastructure, thereby reducing uncertainty and investment risk. These data also provide important regional context for environmental impact assessments and informs evidence-based decisions consistent with government policies and regulations. Effective geomorphic characterisation of the seabed requires a standardised, multi-scalar and collaborative approach to produce definitive geomorphology maps that can support these applications. These maps synthesise interpretations of bathymetry, shallow geology, sedimentology and ecology data, to illustrate the distribution and diversity of seabed features, compositions and processes, including sediment dynamics and seabed stability. We present mapped examples demonstrating the utility of a nationally consistent seabed geomorphology mapping scheme (developed in collaboration with European agencies), for application to a broad range of geographic settings and policy-needs, including the sustainable development of offshore renewable energy in Australia. Presented at the 2024 AMSA-NZMSS Conference Hobart Tas

Dense water formed in the Mertz Polynya supplies the lower limb of the global overturning circulation and ventilates the abyssal Indian and Pacific Oceans. In February 2010, an 80 km section of the Mertz Glacier Tongue calved, altering the regional distribution of ice, and the polynya activity. After calving, the absolute salinity and density of dense shelf water decreased abruptly, and surface waters freshened by up to 1 g kg-1. Break-out and melt of thick multi-year sea ice, likely rich in iron, provided a favourable light and nutrient setting for a bloom of large diatoms, doubling carbon uptake relative to pre-calving conditions. These observations highlight the sensitivity of bottom water formation, biogeochemical cycles and biological productivity to changes in the Antarctic icescape.

Chapter 13 "Bathymetry" was provided by Kim Picard for Volume 3B of the 'Earth Observation Series' published by Australia and New Zealand CRC for Spatial Information. The final volume introduces the Australian environment in terms of geography, climate, biota, and resource management, then covers a broad range of application areas reliant on EO data. Specific case studies are included to demonstrate individual applications. Source - https://www.eoa.org.au/earth-observation-textbooks Recommended Chapter Citation: PIcard, K., Anstee, J.M., and Harrison, B.A. (2021). Bathymetry. Ch 13 in Earth Observation: Data, Processing and Applications. Volume 3B—Surface Waters. CRCSI, Melbourne. pp. 223–241. ISBN 978-0-6482278-5-4 Recommended Citation for Volume 3B: CRCSI (2020). Earth Observation: Data, Processing and Applications. Volume 3B: Applications—Surface Waters. (Eds. Harrison, B.A., Anstee, J.M., Dekker, A.G., King, E.A., Griffin, D.A., Mueller, N., Phinn, S.R., Kovacs, E., and Byrne, G.) CRCSI, Melbourne.