Data

Percentage of time the Shields parameter exceeds 0.25

Geoscience Australia
Hughes, M.
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ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rfr_id=info%3Asid%2FANDS&rft_id=https://ecat.ga.gov.au/geonetwork/srv/eng/catalog.search#/metadata/e3dd1af5-7afb-50fd-e044-00144fdd4fa6&rft.title=Percentage of time the Shields parameter exceeds 0.25&rft.identifier=https://pid.geoscience.gov.au/dataset/ga/77000&rft.publisher=Geoscience Australia&rft.description=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: 5-24Maintenance and Update Frequency: notPlannedStatement: Geoscience Australia's GEOMACS (Geological and Oceanographic Model of Australia's Continental Shelf) model was utilised to produce hindcast hourly time series of continental shelf (~20 - 300 m depth) bed shear stress on a 0.1 degree grid covering the period March 1997 to February 2008 (inclusive). The hindcast data represents the combined contribution to the bed shear stress by waves, tides, wind and density-driven circulation. The Shields parameter was obtained from the GEOMACS model. Please refer to Hughes et al. (2010) for further details. Hughes, M.G., Harris, P.T., Brooke, B.P., 2010. Seabed exposure and ecological disturbance on Australia's continental shelf: Potential surrogates for marine biodiversity. Geoscience Australia Record 2010/43, 77pp.&rft.creator=Hughes, M. &rft.date=2013&rft.coverage=westlimit=110.0; southlimit=-44.0; eastlimit=156.0; northlimit=-7.0&rft.coverage=westlimit=110.0; southlimit=-44.0; eastlimit=156.0; northlimit=-7.0&rft_rights=Creative Commons Attribution 4.0 International Licence http://creativecommons.org/licenses/&rft_rights=Australian Government Security ClassificationSystem https://www.protectivesecurity.gov.au/Pages/default.aspx&rft_subject=oceans&rft_subject=Marine Data&rft_subject=seabed&rft_subject=oceanography&rft_subject=NERP Marine Biodiversity Hub&rft_subject=marine&rft_subject=NERP&rft_subject=Marine Geoscience&rft_subject=EARTH SCIENCES&rft_subject=GEOLOGY&rft_subject=Published_External&rft.type=dataset&rft.language=English Access the data
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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

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Maintenance and Update Frequency: notPlanned
Statement: Geoscience Australia's GEOMACS (Geological and Oceanographic Model of Australia's Continental Shelf) model was utilised to produce hindcast hourly time series of continental shelf (~20 - 300 m depth) bed shear stress on a 0.1 degree grid covering the period March 1997 to February 2008 (inclusive). The hindcast data represents the combined contribution to the bed shear stress by waves, tides, wind and density-driven circulation. The Shields parameter was obtained from the GEOMACS model. Please refer to Hughes et al. (2010) for further details. Hughes, M.G., Harris, P.T., Brooke, B.P., 2010. Seabed exposure and ecological disturbance on Australia's continental shelf: Potential surrogates for marine biodiversity. Geoscience Australia Record 2010/43, 77pp.

Issued: 2013

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156,-7 156,-44 110,-44 110,-7 156,-7

133,-25.5

text: westlimit=110.0; southlimit=-44.0; eastlimit=156.0; northlimit=-7.0

Subjects
Earth Sciences | Geology | Marine Data | Marine Geoscience | NERP | NERP Marine Biodiversity Hub | Published_External | marine | oceanography | oceans | seabed |

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