b'Geophysics in the surveysNewsWhile appearing in last Preview, itcatalogue provides a full suite of theserespect to an ellipsoid vertical datum is somewhat fitting to reproducegrids, including processing notes and(i\x08e\x08, the GDA94 datum which employs Richards most recent accomplishment;intermediate to final products (seethe GRS80 ellipsoid)\x08 The A Series grids namely the development of ahttp://pid\x08geoscience\x08gov\x08au/dataset/ were produced from a combination technically-robust merge of airborne,ga/133023)\x08 of ground gravity data for continental marine and satellite gravity coveringAustralia and data from a global gravity Australia through to its offshoreThe catalogue summary explains: grid for the surrounding region\x08 The continental margins\x08 Packaged under The 2019 Australian National Gravityobservation surface was the ground or the 2020 National Gravity CompilationGrids are two sets of grids (the A andocean surface\x08 The B Series grids used (see below), the final product: a de- B Series) covering the continent ofthe same data as the A Series grids trended global isostatic residual map,Australia and surrounding region (108with the addition of data from twelve was formally unveiled by Richard onto 164 degrees East Longitude, 8 - 48airborne gravity surveys and two the 16 December (Figure 1)\x08 degrees South Latitude)\x08 Each of theairborne gravity gradiometer surveys\x08 two series consist of five grids - threeThe observation surface for the B Series 2020 National Gravity Compilation gravity grids and two supplementarygrids was a smooth drape surface with grids defining the observation surfacea minimum surface clearance of 250 m\x08 Geoscience Australia was pleasedof the gravity grids\x08 The gravity grids(Lane et al 2020)\x08to release the 2019 national gravityprovide values of Free Air Anomaly compilation on 7 October 2020\x08 The(FAA), Complete Bouguer AnomalyReferencerelease represented the first time(CBA), and De-trended Global Isostatic ground gravity, airborne gravity/gravityResidual (DGIR)\x08 The first of theLane, R\x08 J\x08 L\x08, Wynne, P\x08 E\x08, Poudjom gradiometry, satellite and marinesupplementary grids defines the heightDjomani, Y\x08 H\x08, Stratford, W\x08 R\x08, Barretto, gravity observations were combinedof the observation surface with respectJ\x08 A\x08 and Caratori Tontini, F\x08 2020\x08 to produce a series of national gravityto the geoid vertical datum, whilst the2019 Australian national gravity grids grids covering an area more than twicesecond supplementary grid defines theexplanatory notes\x08 Record 2020/22\x08 the size of the country\x08 GAs electronicheight of the observation surface withGeoscience Australia, Canberra\x08Figure 1.B-series de-trended global isotatic residual gravity map of Australia, 2019. Source: Lane et al, 2020. InsetRichard enthusiastically explaining the intricacies of the gravity merge to his GA colleagues, 16 December 2020.FEBRUARY 2021 PREVIEW 14'