Antarctic ice mass fluxes from satellite observations

The Antarctic ice sheet is the largest freshwater store on Earth by an order of magnitude and contains enough ice to increase global sea level by ~65 m. Changes in the input and output of ice (the mass balance) have profound implications for sea level, ocean circulation and inferences concerning the stability of the ice mass. The mass balance of the ice sheet is controlled by both short term and long term processes related to changes in snowfall and ice dynamics. To understand how the ice sheet is behaving now and to be able to predict how it will behave in the future we need to be able to quantify and separate the processes responsible for the trends in mass balance. Some recent research using satellite measurements of elevation change suggests that increased snowfall may be contributing to a positive mass balance for large sectors of the East Antarctic ice sheet (EAIS). This conclusion, however, is not universally accepted and the results do not account for processes related to ice dynamics close to the margins of the ice sheet. Other recent studies, using different satellite data, suggest that overall, the ice sheet is losing a large amount of mass and that the EAIS is roughly in balance. To solve the open and crucial question of whether the EAIS is losing or gaining mass and to better understand the mass balance trends for the whole ice sheet, we will obtain accurate, regional-scale mass balance measurements with well constrained error budgets. In this project, in collaboration with US and Dutch partners, we will determine the mass balance of individual drainage basins covering ~85% of the ice sheet and the larger floating ice shelves using a combination of new and existing satellite observations and atmospheric modelling. In particular, we aim to determine conclusively whether the East Antarctic Ice Sheet is a net source or sink of ocean mass. We also aim to investigate the relative importance of trends in snowfall and ice dynamics in the mass budget of the ice sheet.