Australian National Gravity Grids: Free Air and Bouguer Anomalies at 400m Resolution

2019 Australian National Gravity Grids combine over 1.4 million ground observations from the 1940s onward with satellite and airborne data. The grids, produced by Geoscience Australia and GNS Science, provide Free Air Anomaly, Complete Bouguer Anomaly, and De-trended Global Isostatic Residual values at a 400-metre cell size. Offshore data from a global gravity grid supplements the onshore ground data for continental context.

Use Cases

• Modeling crustal thickness and density variations based on Complete Bouguer Anomaly values.
• Identifying subsurface geological structures for mineral exploration using De-trended Global Isostatic Residual grids.
• Integrating onshore and offshore gravity data for continental-scale geophysical studies.
• Calibrating regional geophysical models with high-resolution 400m grid data.

Strengths

• Grid cell size of 400 metres, an improvement from previous 800-metre versions.
• Incorporates over 1.4 million quality-controlled gravity observations from a national database.
• Combines ground, airborne, and satellite-derived gravity data for comprehensive coverage.
• Includes 345,000 line km of Airborne Gravity Gradiometry data for enhanced resolution in specific areas.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count for the underlying point data is unknown, which may limit suitability assessment.
• Some grids were updated in 2020 to correct artefacts, requiring users to verify they have the latest version.

Provenance

Source

Geoscience Australia and the Institute of Geological and Nuclear Sciences Limited (GNS Science).

Collection Method

Combination of ground gravity data from the Australian National Gravity Database, airborne gravity/gradiometry data, and the NOAA Global Gravity Grid.

Time Range

Observations from the 1940s to 2019.

Freshness

Last updated 2026-04-20 03:10:05.752660; freshness should be verified.

Geography

Australia, including onshore and offshore areas.