Antarctic Ice Mass Change (2003-2016) Jointly Estimated by Satellite Gravimetry and Altimetry

Accurate estimation of ongoing Antarctic ice mass change is important to predict future ice mass loss and subsequent sea level rise. Over the past two decades, Antarctic ice mass changes have been observed by the gravity recovery and climate experiment (GRACE) gravity mission, but the low spatial resolution of GRACE has limited understanding of glacial-scale contributions. In this study, we combine GRACE and altimetry data to obtain mass change estimates with greatly improved spatial resolution. Combined estimates are obtained by a constrained linear deconvolution algorithm used in a previous GRACE study. Satellite altimetry observations are introduced as an a priori and resulting estimates retain the high spatial resolution of satellite altimetry, but when smoothed agree with low resolution GRACE data. These glacial-scale estimates also agree with ice budget calculations using the input-output method.