Australian National Gravity Anomaly Grid with Airborne Data

Over 1.8 million gravity observations underpin this 2019 national grid, including nearly 1.4 million ground stations and 451,000 line kilometers of airborne surveys. The Australian Ocean Data Network compiled this first vertical derivative grid from the Australian National Gravity Database and global offshore sources. It represents gravity data collected by government, industry, and research bodies from the 1940s to 2019.

Use Cases

• Map subsurface density contrasts by interpreting the first vertical derivative of the complete spherical cap Bouguer anomaly grid.
• Integrate airborne gravity gradiometry line data with ground station observations to improve resolution in areas with sparse ground coverage.
• Analyze the 0.00417-degree cell size grid to identify geological structures like basins or intrusions across the Australian continent and margins.
• Apply terrain corrections using the integrated offshore bathymetry and onshore topography data to refine gravity anomaly models.

Strengths

• Integrates approximately 1.8 million gravity observations from multiple sources.
• Combines ground data with 345,000 line km of airborne gravity and 106,000 line km of airborne gravity gradiometry for enhanced coverage.
• Ground station spacing is detailed, ranging from 11 km down to less than 1 km across major parts of the continent.

Limitations

• Specific row count for the final grid product is not provided.
• The underlying gravity observations have variable density, with station spacing varying significantly across the continent.
• The core gravity database snapshot is from September 2019, with no stated update plan for the grid.

Provenance

Source

Australian National Gravity Database (ANGD), Global Gravity grid v28.1 from Scripps Institution of Oceanography/NOAA/NGA, and airborne surveys.

Collection Method

Data processed via standard geophysical methods, quality-checked by GA geophysicists, and gridded using a fast Fourier transform (FFT) process.

Time Range

1940s to 2019 (for ground observations); grid compilation date is 2019.

Freshness

Data represents a 2019 compilation; last metadata update was 2026-04-04.

Geography

Australia and its continental margins.