Gravity Anomaly Grid of the Australian Region  

Authors / CoAuthors

Murray, A.

Abstract

This grid represents gravity anomalies of the Australian region. The grid combines accurate onshore gravity measurements, a sub-sample of the levelled offshore marine gravity traverses with satellite data used in areas where there is no marine data. The cell values represent simple Bouguer anomalies at a density of 2.67 tm-3 onshore and free-air anomalies offshore. The grid cell size is 0.5 minutes of arc, which is equivalent to about 800 metres. The smallest wavelength contained in the grid is 1600 m.

Product Type

dataset

eCat Id

38953

Contact for the resource

Keywords

• GIS DatasetNational

( Theme )

• geophysics

( Theme )

• gravity

Australian and New Zealand Standard Research Classification (ANZSRC)

• Gravimetrics

• Published_Internal

Publication Date

2001-01-01T00:00:00

Creation Date

Security Constraints

Australian Government Security ClassificationSystem    

Classification - unclassified

Legal Constraints

Creative Commons Attribution 4.0 International Licence    

Access - restricted

Use - license

Status

Purpose

Maintenance Information

continual

Topic Category

geoscientificInformation

Series Information

Lineage

The gravity grid was derived from the complete onshore database as at April 2001 and levelled marine traverses. A two-pass process (1.5 minute then 0.5 minute) was used to generate the grid from a composite file containing 815 000 land observations, 1.5 million marine values and 2.2 million satellite values. For the satellite values refer to Sandwell, D.T. and W.H.F.Smith, Marine Gravity Anomaly from Geosat and ERS-1 Altimetry, J. Geophys. Research, 1997. The 0.5 minute grid is the finest mesh that is currently meaningful over the whole continent given that much of the data coverage is spaced at 4 or 11 km. <p><b>The parameters of the grid are:</b> <br>Grid spacing: 0.5 minute = 0.0083333 degree (approx. 800 m) <br>Projection: Rectangular in latitude and longitude <br>Grid size: 6740 points longitude x 4815 points latitude <br>Grid origin: 7 degrees 56.5 min south, 105 deg 56.5 min east (1,1) <br>Bottom right corner: 48 deg 3.5 min south, 162 deg 6.0 east (4815,6740) <br>Scaling: Nil. Values are in decimal units (&micro;ms&minus;&sup2; (micro metres per second squared)) <br>Null value: 0.10E+12 <br>Data accuracy: 5 units, maximum error 100 units onshore <br>Data precision: 1 unit <p><b>Gravity Datum</b> <br>The gravity data as supplied are based on the IGSN71 datum and ISOGAL84 scale. The gravity unit used is micrometres per second squared which is equivalent to 0.1 milligals.

Parent Information

Extents

[-48.0, -7.0, 105.0, 162.0]

Reference System

Spatial Resolution

Service Information

Associations

Downloads and Links

Source Information

Source data not available.