Presented by Jonathan Bamber,University of Bristol, UK, at the ESA-CliC Earth Observation and Arctic Science Priorities Meeting, Norway, 2015
A major uncertainty in determining the mass balance of the Antarctic ice sheet from satellite gravimetry, and, to a lesser extent, altimetry measurements is the necessary correction for viscous flow in the Earth’s interior and surface deformation related to the glacial isostatic adjustment (GIA). Although much progress has been made in consistently modelling ice sheets and solid Earth deformation, predictions of GIA remain ambiguous and their uncertainty continues to be larger than the GRACE mass trends for Antarctica.
Within the STSE project REGINA, temporal linear trends in the altimetry, gravimetry and GPS data were consistently combined using a novel approach based on Earth model response functions. This allowed to separate present-day ice-mass change from GIA, as well as assesses the influence of Earth structures most suitable for West Antarctica. The REGINA project successfully determined the GIA impact on CryoSat-2 elevation rates and GRACE mass trends. However, it also revealed substantial differences to and among published GIA predictions -- both in terms of the total and regional apparent GIA-induced mass change, introducing great uncertainty in reconciling ice-mass balance estimates from satellite altimetry and gravimetry.
For more information on the meeting this was presented at, see http://www.climate-cryosphere.org/meetings/esa-arctic-2015