Citation

Geoscience Australia provides most of its products for free under a Creative Commons Attribution 3.0 Australia Licence. We only require that you reference the use of our data or information using the following citation:
Nichol, S.L. & Siwabessy, P.J.W., 2014. Flinders Commonwealth Marine Reserve Seabed Hardness Analysis. Geoscience Australia, Canberra.

Abstract

This resource contains an analysis of seabed hardness using multibeam sonar backscatter data for the continental shelf area of Flinders Commonwealth Marine Reserve, northeast Tasmania. Multibeam data were collected by Geoscience Australia and University of Tasmania in June-July 2012 (survey GA0337) on RV Challenger using a Kongsberg EM3002 300 kHz multibeam sonar system mounted in single head configuration. Multibeam data (bathymetry and backscatter) were acquired at 40 pre-determined stations, each covering an area approximately 200 x 200 m. The location of stations was selected using a Generalised Random Tessellation Stratified (GRTS) sampling design that ensured an even spatial distribution of sites. Multibeam data were also collected along transits between GRTS stations (410 line km) and across a 30 km2 area of the outer shelf. Backscatter data are gridded to 2 m spatial resolution. The analysis of backscatter data includes an estimation of the probability of seabed hardness (p-hard) using the Angular Response Curve. The Flinders CMR survey was a pilot study undertaken in 2012 as part of the National Marine Biodiversity Hub's National Monitoring Evaluation and Reporting Theme. The aim of this theme is to develop a blueprint for the sustained monitoring of the South-east Commonwealth Marine Reserve Network. The Marine Biodiversity Hub is supported through funding from the Australian Government's National Environmental Research Program (NERP), administered by the Department of the Environment.
Google map showing geographic bounding box with values North bound -40.4 East bound 148.85 West bound 148.55 South bound -40.85
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Product Type/Sub Type

dataset - Marine Data

Constraints

license
Creative Commons Attribution 3.0 Australia Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

2014

Product Type

dataset

Topic Category

geoscientificInformation

Keywords

Marine Data
NERP Marine Biodiversity Hub
habitat
continental shelf
backscatter
marine
Marine Geoscience

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-40.4
East bound
148.85
West bound
148.55
South bound
-40.85

Lineage

Raw backscatter data were first processed using CMST-GA MB Process v12.05.07 software. The fully processed backscatter strengths were corrected for transmission loss and insonification area. The process within the toolbox also involved removal of the system transmission loss, removal of the system model, calculation of the incidence angle and removal of the angular dependence. The resulatnt grid values are the average values of the processed backscatter point data within each 2 m grid cell, normalised to the backscatter strength at an angle of 25 degrees. The probability of seabed hardness (p-hard) was estimated using the Angular Response Curve (ARC) which represents the backscatter value in relation to the incidence angle, defined as the angle between the acoustic signal return from the seabed and the vertical axis of the vessel. Representative areas of seabed with hard substrate, as identified from towed underwater video, were selected for extraction of ARCs. The average ARC was then derived to represent the reference ARC for hard seabed. This reference curve was compared to all other ARCs for the survey area using the Kolmogorov-Smirnov goodness of fit to estimate the probability value of the seabed hardness (p-hard). Finally, the Inverse Distance Weighted (IDW) interpolation technique was used to produce a continuous layer of the p-rock for the whole study area.

Digital Transfer Options

onLine

Distributor

Role
distributor
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address

Metadata File Identifier

f7c38ecc-8fee-70c9-e044-00144fdd4fa6

Metadata Standard Name

ANZLIC Metadata Profile: An Australian/New Zealand Profile of AS/NZS ISO 19115:2005, Geographic information - Metadata

Metadata Standard Version

1.1

Metadata Date Stamp

2014-05-23

METADATA SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
pointOfContact
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address
For information on acquiring this product,
please contact Geoscience Australia Client Services via:

fax:
+61 2 6249 9960; or
phone:
1800 800 173 (within Australia);
 
+61 2 6249 9966 (outside Australia).