Progress in modelling and observing Antarctic glacial isostatic adjustment

Abstract

In the RAS Bullerwell Lecture for 2012, Matt A King outlines ways to observe and model glacial uplift, highlighting the need for comprehensive data collection and more sophisticated Earth models.King: Bullerwell lecture

Accelerated West Antarctic ice mass loss continues to outpace East Antarctic gains

“…The continent-wide Antarctic pattern of mass change agrees generally well with that recovered by previous studies (Chen et al, 2008(Chen et al, , 2009Horwath et al, 2012;King et al, 2012;Shepherd et al, 2012;Luthcke et al, 2013;Velicogna and Wahr, 2013). Our individual inversions for the trends displayed by smaller subregions reveals that West Antarctica (Fig.…”

“…Compared to other gravitybased approaches, we do not a priori remove correlations between spherical-harmonic coefficients (Swenson and Wahr, 2006), and neither smooth nor project on a predefined basin structure (Wouters et al, 2008;King et al, 2012;Sasgen et al, 2012Sasgen et al, , 2013. Rather, we determine full-resolution best-localized scalar Slepian basis sets for large regions encompassing several basins; we project the GRACE Level 2 coefficients onto well-concentrated truncated subsets of each basis; and then we estimate the correlation structure of the residuals as part of the estimation of the spatiotemporal behavior of the Slepian coefficient time series.…”

“…In Antarctica, improvements in modeling the ongoing glacio-isostatic adjustment from the Last Glacial Maximum deglaciation (for an accessible review, see King, 2013) have increased the precision of gravimetric mass balance estimates. As a result, the detailed pattern of mass change has been the focus of recent GRACE studies (Sasgen et al, 2010Harig and Simons, 2012;Horwath et al, 2012;King et al, 2012;Lee et al, 2012;Luthcke et al, 2013;Velicogna and Wahr, 2013;Bouman et al, 2014). To inform our estimates of sea level change for the coming century it is imperative that we continue to build and improve the detailed record of changes in ice mass (Overpeck et al, 2006;Little et al, 2013aLittle et al, , 2013b.…”

Rapid ice unloading in the Fleming Glacier region, southern Antarctic Peninsula, and its effect on bedrock uplift rates

“…Due to the demise of the major ice sheets following the Last Glacial Maximum (LGM), iceocean surface loads on the solid Earth have been redistributed, reshaping Earth's gravitational field, altering the orientation of its rotation pole, and causing viscoelastic deformation of the solid Earth (Peltier, 2004); these processes are collectively known as glacial isostatic adjustment (GIA). Inputs required in a GIA model include the rheology of the Earth and the spatiotemporal evolution of ice-loading, enabling the prediction of three-dimensional solid earth deformation and geoid rate change (King, 2013;Peltier et al, 2015;Whitehouse et al, 2012a).…”