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Abstract:
Antarctic snow accumulation is a direct regulator of the global sea level changes, but quantification of its long-term evolution at the ice sheet scale is challenging. Here, we combine a most recently complied dataset of ice core records with spatial coherence patterns from five different reanalysis products and two regional climate models, for the first time, to produce a reconciled 310-year reconstruction of spatially and temporally complete snow accumulation over the Antarctic Ice Sheet (AIS). Despite greatly variable signs and magnitudes of reconstructed snow accumulation trends at the different regions, a significant positive trend (3.6±0.8 Gt yr-1 decade-1) is observed for snow accumulation over the entire AIS during the past 300 years, with a larger increase rate since 1801. The increased snow accumulation cumulatively dampened global sea-level rise by ~14 mm between 1901 and 2010. The first and second modes of the empirical orthogonal function analysis (EOF1 and EOF2) capture 38.0% and 24.6% of the total variability in reconstructed snow accumulation, respectively. EOF1 consists of an east-west dipole of snow accumulation changes over West Antarctica, primarily driven by the southern annular mode (SAM) variability. EOF2 represents a strong signal over the whole Antarctic Peninsula and the coastal West Antarctica, which is not associated with SAM, but with El Niño–Southern Oscillation (ENSO) at the decadal scale.
