b'Geophysics in the surveysNewsFigure 2.B-series de-trended global isotatic residual gravity map of Australia, 2019 (Lane et al 2020). intermediate to final products (seesecond supplementary grid defines theof gravity correction, through to the http://pid.geoscience.gov.au/dataset/ height of the observation surface withmethodology and applications of the ga/133023). respect to an ellipsoid vertical datumnew continent-wide dataset (see https://The catalogue summary explains: (i.e., the GDA94 datum which employsyoutu.be/3CyqrqBM0xg). Also released the GRS80 ellipsoid). The A Series gridswas the updated portal to support The 2019 Australian National Gravitywere produced from a combinationthe Australian Fundamental Gravity Grids are two sets of grids (the A andof ground gravity data for continentalNetwork (AFGN), the series of absolute B Series) covering the continent ofAustralia and data from a global gravitygravity stations across the country used Australia and surrounding region (108grid for the surrounding region. Theto level the numerous individual and to 164 degrees East Longitude, -48 toobservation surface was the ground orrelative gravity surveys that make up -8 degrees North Latitude). Each of theocean surface. The B Series grids usedthe compilation and provide calibration two series consist of five grids - threethe same data as the A Series gridspoints for industry surveys (https://portal.gravity grids and two supplementarywith the addition of data from twelvega.gov.au/persona/afgn). The new portal grids defining the observation surfaceairborne gravity surveys and twogives unparalleled access to station of the gravity grids. The gravity gridsairborne gravity gradiometer surveys.information, locality and condition (see provide values of Free Air AnomalyThe observation surface for the B SeriesFigure 3).(FAA), Complete Bouguer Anomalygrids was a smooth drape surface with (CBA), and De-trended Global Isostatica minimum surface clearance of 250 m.Together, the national coverage and the Residual (DGIR). The first of the(Lane et al 2020). AFGN represent one of the most detailed supplementary grids defines the heightgravity coverages in the world. They of the observation surface with respectThe above data release was accompaniedprovide an unprecedented picture of to the geoid vertical datum, whilst theby a public seminar covering the basicsAustralias gravity field that will help map DECEMBER 2020 PREVIEW 14'