Enhanced mass balance of Antarctica from RINGS airborne grounding line survey

Determining the mass balance of Antarctica by satellite gravimetry, altimetry and input-output methods is still suffering from large discrepancies between methods, especially for East Antarctica. Error sources for the different estimation methods include GIA for GRACE/GRACE-FO, firm compaction for satellite altimetry, and poorly known interior snow fall and grounding line mass flux for outlet glaciers in the input-output method. To narrow down uncertainties for the latter, an international SCAR project “RINGS” was initiated in 2023, aiming as a primary goal to cover all major unmapped outlet glaciers with new radar ice thickness data in the coming years. A unique multi-disciplinary airborne remote sensing RINGS campaign was carried out as part of a first circumnavigation of Antarctica 2024/25, using a Twin-Otter as dedicated science aircraft. The airborne campaign instruments included a 30 GHz deep ice sounding radar, a 5 GHz broadband snow radar, along with scanning lidar, nadir and side-looking imagery, and gravimetry, as well as atmosphere monitoring sensors for chemistry and aerosols. In the presentation we outline the results of the RINGS airborne campaign, the impact on the input-output method of the new outlet glacier thicknesses, and compare the changes to current GRACE/GRACE-FO mass balance results.