Predictions of secular geoid changes from Late Pleistocene and Holocene Antarctic ice-ocean mass imbalance

Abstract

Estimates on ice volume changes in Antarctica, from both contemporary mass imbalance during the last hundred to thousand years and ice volume changes during the last glacial cycles, are difficult to obtain. Future satellite-gravity missions monitoring secular changes in gravity as a proxy of mass changes of the Antarctic Ice Sheet will therefore provide an additional important constraint on the Antarctic Ice Sheet history. We assess the contributions from both past ice volume changes during the last glacial cycles and present ice imbalances over Antarctica, using a variety of published ice models. Model predictions of secular changes of the geoid anomaly based on plausible mantle viscosity profiles enable us to discuss the importance of past and present ice volume changes and their characteristic signatures. While uncertainties arising from the viscosity profile are of secondary importance for model predictions of the secular change of the geoid anomaly, we expect significant bias of the observed signal from uncertainties in the timing of the end of deglaciation, which is in agreement with previous studies. Hence, the benefit of inferring present-day Antarctic ice imbalance from satellite-gravity missions will depend on improvements to ice models for the last glacial cycle.