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

Data from the 1940s to 2019, combined from over 1.4 million ground gravity observations, airborne surveys, and global satellite models. This series of grids provides Free Air Anomaly, Complete Bouguer Anomaly, and De-trended Global Isostatic Residual values for Australia at a 400-meter cell size. The grids were produced by Geoscience Australia and GNS Science, with offshore data included for context.

Use Cases

• Modeling crustal density variations based on Complete Bouguer Anomaly values.
• Interpreting geological structures using De-trended Global Isostatic Residual grids.
• Integrating onshore and offshore gravity data for continental-scale geophysical analysis.
• Improving resolution in areas with sparse ground data using included airborne gravity gradiometry surveys.

Strengths

• Incorporates over 1.4 million quality-controlled gravity observations from the Australian National Gravity Database.
• Improved 400-meter cell size, a resolution increase from previous 800-meter grids.
• Combines onshore ground data with offshore satellite-derived gravity and 451,000 line km of airborne surveys for broader context.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.
• Some grids (DGIR) were updated in 2020 due to artefacts, requiring users to verify they have the corrected version.

Provenance

Source

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

Collection Method

Combination of ground, airborne, and satellite-derived gravity data from multiple government, industry, and research sources.

Time Range

1940s to 2019

Freshness

Last updated 2026-03-25 15:29:44.068036; freshness should be verified.

Geography

Australia, including onshore and offshore regions.