Ice Sheet Mass Changes over Antarctica Based on GRACE Data

Assessing changes of the mass balance in the Antarctic ice sheet in the context of global warming is a key focus in polar study. This study analyzed the spatiotemporal variation in the Antarctic ice sheet's mass balance, both as a whole and by individual basins, from 2003 to 2016 and from 2018 to 2022 using GRACE RL06 data published by the Center for Space Research (CSR) and ERA-5 meteorological data. It explored the lagged relationships between mass balance and precipitation, net surface solar radiation, and temperature, and applied the random forest method to examine the relative contributions of these factors to the ice sheet's mass balance within a nonlinear framework. The results showed that the mass loss rates of the Antarctic ice sheet during the study periods were -123.3 +/- 6.2 Gt/a and -24.8 +/- 52.1 Gt/a. The region with the greatest mass loss was the Amundsen Sea in West Antarctica (-488.8 +/- 5.3 Gt/a and -447.9 +/- 14.7 Gt/a), while Queen Maud Land experienced the most significant mass accumulation (44.9 +/- 1.0 Gt/a and 30.0 +/- 3.2 Gt/a). The main factors contributing to surface ablation of the Antarctic ice sheet are rising temperatures and increased surface net solar radiation, each showing a lag effect of 1 month and 2 months, respectively. Precipitation also affects the loss of the ice sheet to some extent. Over time, the contribution of precipitation to the changes in the ice sheet's mass balance increases.