Partitioning the contribution of surface mass balance and ice discharge in Antarctic glacier mass variations (2003-2020)

We partitioned Antarctic ice mass changes (2003-2020) into the contributions of surface mass balance (SMB) and ice discharge over 27 drainage basins, based on the combined estimates of satellite gravimetry and altimetry observations and a numerical SMB model. Our analysis indicates that the ice discharge has played a dominating role in ongoing ice mass losses and accelerations, especially in the glaciers near Amundsen and Bellingshausen Sea in West Antarctica. In particular, the mass losses in the Thwaites and Pine Island Glaciers have been mostly controlled by ice discharge, while the contribution of SMB has been minor. On the other hand, SMB contributed large portions of ice mass imbalance in East Antarctica, such as glaciers near the Dronning Maud Land and Wilkes Land. An inaccurate GIA model is a potential source of uncertainty in our estimates.