Gravity field data are a key element of EO to aid the understanding of the tectonics and deep geological structures of the polar regions. With the limited polar coverage of GOCE (limited to 83.3 degrees N and S), airborne gravity data plays an important role both to fill the polar gaps, as well as providing higher resolution gravity field mapping than possible from space. While the Arctic has been well-covered with airborne and marine surveys since the early 2000’s, with many new surveys carried out in the last decade, Antarctica airborne coverage continues to be more sparse, with data from many older surveys often heavily biased and error prone. GOCE, supplemented with the ESA PolarGAP airborne geophysics campaign and other recent high-quality surveys, have provided new opportunities for providing enhanced gravity field models of Antarctica.
As part of the ESA 4D-Antarctica project, a new compilation of GOCE/GRACE EO data, as well as airborne, surface, and marine altimetry data has been developed, and presented both as grids of gravity anomalies, gravity gradients and geoid. The new compilation gives a much improved basis for understanding the solid earth structures below the Antarctic ice sheet, and highlights also the outstanding quality of GOCE data. The new 4D compilation also highlights the need for more geophysical data, especially in East Antarctica.
Airborne gravity surveys in the coastal regions are important also for climate change applications, as gravity represents more or less the only practical method for mapping large-scale bathymetry under the ice shelves, and aid in the radar measurement of glacier thickness for large, deep outlet glaciers. A new initiative – RINGS – have recently been adopted as an Action Group of SCAR, in order to prepare plans for an international complete geophysical and glaciological airborne mapping of the entire Antarctica grounding line zone, in an internationally coordinated multi-aircraft, multi-sensor project. Experience from the ESA PolarGap project, and the improved sensors of modern state-of-the-art airborne geophysics, shows that even highly challenging logistics projects can be carried out with success by true international cooperation, and we ask the community to support the RINGS initiative, not just for gravity, but also for magnetic, radar, and lidar data, useful for a broad range of sciences, as well as validation of future satellites.