Antarctic outlet glacier mass change resolved at basin scale from satellite gravity gradiometry

Abstract

The orbit and instrumental measurement of the Gravity Field and Steady State Ocean Circulation Explorer (GOCE) satellite mission offer the highest ever resolution capabilities for mapping Earth's gravity field from space. However, past analysis predicted that GOCE would not detect changes in ice sheet mass. Here we demonstrate that GOCE gravity gradiometry observations can be combined with Gravity Recovery and Climate Experiment (GRACE) gravity data to estimate mass changes in the Amundsen Sea Sector. This refined resolution allows land ice changes within the Pine Island Glacier (PIG), Thwaites Glacier, and Getz Ice Shelf drainage systems to be measured at respectively −67 ± 7, −63 ± 12, and −55 ± 9 Gt/yr over the GOCE observing period of November 2009 to June 2012. This is the most accurate pure satellite gravimetry measurement to date of current mass loss from PIG, known as the “weak underbelly” of West Antarctica because of its retrograde bed slope and high potential for raising future sea level.

Mass balance reassessment of glaciers draining into the Abbot and Getz Ice Shelves of West Antarctica

“…The reassessed mass budget estimate presented in this paper is shown in black. The individual studies and mass balance figures are presented in Table S3 and Table S4 of the supporting information for the Bellingshausen Sea and Getz Sectors, respectively [ Rignot et al ., ; Sasgen et al ., , ; King et al ., ; Bouman et al ., ; McMillan et al ., ; Wouters et al ., ; Zwally et al ., ; Groh and Horwath , ; Martín‐Español et al ., ].…”

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

“…Observations indicate that the Antarctic Ice Sheet is very sensitive to climate change (Raymo and Mitrovica, 2012;Bromwich et al, 2013;Cook et al, 2013;Kopp et al, 2013), and knowledge of individual glaciers and ice streams is important to understand the process. Ultimately, the continental ice sheet response to global change is the sum of the behaviors within individual drainage basins, which are subject to the combined effects of surface mass balance, calving and basal melting, and influenced by their geographic location and topography.…”

“…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.…”

Using ground gravity to improve ice mass change estimation from GOCE gravity gradients in mid-west Greenland

“…One can also get improvement by combining GRACE data with GOCE vertical gravity gradients in monthly means. A similar investigation was carried out by Bouman et al (2014).…”