Antarctic ice mass variations from 1979 to 2017 driven by anomalous precipitation accumulation

Abstract

Antarctic ice mass balance is determined by precipitation and ice discharge, and understanding their relative contributions to contemporary Antarctic ice mass change is important to project future ice mass loss and resulting sea level rise. There has been evidence that anomalous precipitation affects Antarctic ice mass loss estimates, and thus the precipitation contribution should be understood and considered in future projections. In this study, we revisit changes in Antarctic ice mass over recent decades and examine precipitation contributions over this period. We show that accumulated (time-integrated) precipitation explains most inter-annual anomalies of Antarctic ice mass change during the GRACE period (2003–2017). From 1979 to 2017, accumulated Antarctic precipitation contributes to significant ice mass loss acceleration in the Pacific sector and deceleration in the Atlantic-Indian Sectors, forming a bi-polar spatial pattern. Principal component analysis reveals that such a bi-polar pattern is likely modulated by the Southern Annular Mode (SAM). We also find that recent ice mass loss acceleration in 2007 is related to a variation in precipitation accumulation. Overall ice discharge has accelerated at a steady rate since 1992, but has not seen a recent abrupt increase.

Analysis of the interannual variability in satellite gravity solutions: detection of climate modes fingerprints in water mass displacements across continents and oceans

“…Besides, the mass balance of inland glaciers is also impacted by precipitation, that has been shown to contain intermittent ENSO and strong SAM signatures (e.g. Sasgen et al 2010;Kim et al 2020). Numerous processes triggering ice-mass changes in West Antarctica are therefore susceptible to contain ENSO signatures.…”

Climate variability as a major forcing of recent Antarctic ice-mass change

“…S1) to explore the role of large-scale climate forcing on ice-sheet change. Unlike previous comparison of GRACE and climate indices (9)(10)(11)26 ), we first cumulatively sum the normalized indices, reflecting that the raw indices are related to mass flux rather than the cumulative mass observed by GRACE, something recognized in studies of ice shelf elevation change (27 ) and time-integrated SMB (15 ). The resulting cumulative SAM index (hereafter SAM Σ ) shows an upward trend over the GRACE period while cumulative Niño3.4 index (hereafter Niño3.4 Σ ) shows mostly decadal variability (28 ) but negligible trend over this period (Fig.…”

“…Comparisons (9,12 ) of satellite gravimetric mass-change time series from the Gravity Recovery and Climate Experiment (GRACE) mission and its Follow-On (GRACE-FO) to SAM indices suggest that SAM is not a primary influence on the observed inter-annual variability, although one study suggests secondary modes of variability are moderately correlated with SAM (13 ). This lack of clarity is somewhat surprising given that SAM is known to strongly influence the pattern of surface mass balance (SMB) (14 ) and its variability (15,16 ) and, with SAM's strong trend since the ˜1940s (17,18 ), contributing to regional multi-decadal trends (19 ) in SMB. These SMB mass changes should be evident in time series of ice sheet mass change in addition to any oceanographic response to SAM (20)(21)(22).…”

Antarctic Ice Mass Change (2003–2016) Jointly Estimated by Satellite Gravimetry and Altimetry

“…We set linear, quadratic, annual, and semiannual variabilities as regression model parameters and adopted a Generalized Gauss Markov (GGM) noise model to explain the residuals. The GGM model is known to best describe the noise characteristics of AIS SMB variability (King & Watson, 2020), which accounts for most of the subdecadal AIS mass changes (Kim et al., 2020). Uncertainties of GIA correction were also included.…”