Radiometric Grid of Australia (Radmap) v4 2019 filtered terrestrial dose rate

Brief description

This record was harvested by RDA at 2025-03-05T09:51:51.968+11:00 from NCI's Data Catalogue where it was last modified at 2018-04-20T05:51:54.

Full description

The filtered terrestrial dose rate grid is a derivative of the 2019 radiometric or gamma-ray grid of Australia, made of a combination of over 600 individual survey grids. The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data are collected on airborne geophysical surveys conducted by Commonwealth, State and Northern Territory Governments and the private sector. The terrestrial dose rate grid is derived as a linear combination of the filtered K, U and Th grids. A low pass filter is applied to the unfiltered grid to generate the filtered terrestrial dose rate grid. The grid cell size is about 100m (0.001 degrees). -- This record represents data published by NCI. It uses catalogue metadata modified from Geoscience Australia. See our Record Lineage Information for more details.

Lineage

The filtered terrestrial dose rate grid is a derivative of the 2019 radiometric or gamma-ray grid of Australia. The radiometric grid of Australia is derived by merging over 600 airborne gamma-ray spectrometric surveys by the Commonwealth, State and Territory Governments and held in the national radioelement database of Australia. The cell sizes of the original survey grids range from 50 m through 800 m, but most have a cell size of about 100 m. The original survey grids are levelled to each other, and to the Australia Wide Airborne Geophysical Survey (AWAGS). The grids were then re-sampled to generate the Radiometric Map of Australia grids with a cell size of about 100m (0.001 degrees). Since the AWAGS traverses are consistent with the International Atomic Energy Agency’s (IAEA) radioelement datum, the new continental merges are levelled to this datum as well. The data quality varies depending on the survey. The data are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The final grid is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. The filtered terrestrial dose rate grid was calculated by applying a low pass filter on the terrestrial dose rate grid.