Detailed ice loss pattern in the northern Antarctic Peninsula: widespread decline driven by ice front retreats

T A Scambos,S R M Ligtenberg,J Bohlander,E Berthier,T Haran,C A Shuman,A J Cook

doi:10.5194/tc-8-2135-2014

Abstract

Abstract. The northern Antarctic Peninsula (nAP, < 66° S) is one of the most rapidly changing glaciated regions on earth, yet the spatial patterns of its ice mass loss at the glacier basin scale have to date been poorly documented. We use satellite laser altimetry and satellite stereo-image topography spanning 2001–2010, but primarily 2003–2008, to map ice elevation change and infer mass changes for 33 glacier basins covering the mainland and most large islands in the nAP. Rates of ice volume and ice mass change are 27.7± 8.6 km3 a−1 and 24.9± 7.8 Gt a−1, equal to −0.73 m a−1 w.e. for the study area. Mass loss is the highest for eastern glaciers affected by major ice shelf collapses in 1995 and 2002, where twelve glaciers account for 60% of the total imbalance. However, losses at smaller rates occur throughout the nAP, at both high and low elevation, despite increased snow accumulation along the western coast and ridge crest. We interpret the widespread mass loss to be driven by decades of ice front retreats on both sides of the nAP, and extended throughout the ice sheet due to the propagation of kinematic waves triggered at the fronts into the interior.

Highlights

Studies based on gravitational change detection using the Gravity Recovery and Climate Experiment satellite system (GRACE) have an inherent spatial resolution of roughly 250 km scale (Ivins et al, 2011; Luthcke et al, 2013; Sasgen et al, 2013), far larger than the scale of the northern Antarctic Peninsula (nAP) individual glacier basins and islands
In light of known climate-related changes in the region, such as increasing surface air temperatures and surface melting, regional sea ice decline, and increasing accumulation (e.g., Mulvaney et al, 2012; Zagorodnov et al, 2012; Stammerjohn et al, 2008; Lenaerts et al, 2012; Barrand et al, 2013), our study reveals a pattern of ice mass loss in space and in time that may be similar to the characteristics of mass loss in other areas of Antarctica in the coming century
A recent study (Neild et al, 2014), using an earlier version of our presented data combined with continuous GPS uplift measurements at sites in the peninsula, modeled both the elastic response and long-term isostatic rebound in the region, showing that the nAP is underlain by very low viscosity mantle

Summary

Introduction

The northern Antarctic Peninsula (nAP) is one of two areas of the Antarctic ice sheet showing major mass loss, the other being the Amundsen Sea coast of West Antarctica’s ice sheet.Previous studies have shown large negative mass imbalances and significant elevation losses for the nAP (Ivins et al, 2011; Shepherd et al, 2012; Luthcke et al, 2013; Sasgen et al, 2013; McMillan et al, 2014). Mass budget methods (Rignot et al, 2004, 2008; Rott et al, 2011; Shepherd et al, 2012), which aim to difference outflowing ice flux and surface mass balance (SMB) for each glacier basin, have to date shown results that are difficult to reconcile with other studies of the same glaciers (Shuman et al, 2011; Berthier et al, 2012). This is primarily due to spatially coarse SMB estimates from

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