Short-term Antarctic ice sheet mass anomalies revealed by daily GRACE/FO satellite gravimetry

The Antarctic Ice Sheet (AIS), as the largest freshwater reservoir on Earth, plays a critical role in modulating global sea-level rise, polar hydrological processes, and the evolution of the Earth’s climate system. While Gravity Recovery And Climate Experiment and its successor Follow-On (GRACE/FO) have been instrumental in tracking ice sheet mass changes, the coarse temporal resolution of the commonly-used monthly satellite gravity fields limits the detection of transient, short-term mass anomalies. To overcome this limitation, we simultaneously employ monthly, 10-day, and daily GRACE/FO solutions to retrospectively identify and attribute anomalous AIS month-to-month mass change events. Using monthly and 10-day GRACE/FO satellite gravity field solutions during 2002–2024, we detected 32 significant AIS month-to-month mass change events, among which four exhibited distinct anomalies. Notably, daily GRACE/FO solutions further reveal that an anomalous ice sheet mass gain event in the summer of 2011/2012 was triggered by a 5-day extreme precipitation episode in December 2011, which was independently validated by Global Navigation Satellite System (GNSS) vertical land motion time series. This short-term precipitation episode, driven by intense atmospheric rivers (ARs), resulted in sustained positive mass anomaly of AIS over the subsequent approximately 50 days, with a mean mass increase of 134.36 Gt, equivalent to a 0.37 mm decrease in global mean sea-level. Furthermore, the inconsistency between the anomalous AIS mass deficit and the surface mass balance indicates that subglacial hydrological processes may also exert significant influence on the short-term AIS mass anomalies. Overall, our findings underscore the unique value of daily GRACE/FO gravity field solutions in monitoring the transient ice sheet mass anomalies in response to extreme climatic events.