Recent high-resolution Antarctic ice velocity maps reveal increased mass loss in Wilkes Land, East Antarctica

Abstract

We constructed Antarctic ice velocity maps from Landsat 8 images for the years 2014 and 2015 at a high spatial resolution (100 m). These maps were assembled from 10,690 scenes of displacement vectors inferred from more than 10,000 optical images acquired from December 2013 through March 2016. We estimated the mass discharge of the Antarctic ice sheet in 2008, 2014, and 2015 using the Landsat ice velocity maps, interferometric synthetic aperture radar (InSAR)-derived ice velocity maps (~2008) available from prior studies, and ice thickness data. An increased mass discharge (53 ± 14 Gt yr−1) was found in the East Indian Ocean sector since 2008 due to unexpected widespread glacial acceleration in Wilkes Land, East Antarctica, while the other five oceanic sectors did not exhibit significant changes. However, present-day increased mass loss was found by previous studies predominantly in west Antarctica and the Antarctic Peninsula. The newly discovered increased mass loss in Wilkes Land suggests that the ocean heat flux may already be influencing ice dynamics in the marine-based sector of the East Antarctic ice sheet (EAIS). The marine-based sector could be adversely impacted by ongoing warming in the Southern Ocean, and this process may be conducive to destabilization.

Mass Balance Assessment of the Amery Ice Shelf Basin, East Antarctica

“…A comparison of our results with those of previous studies (Table ) suggests similar ice discharge values for the AIS basin when the ice thickness at the flux gate is mostly derived from airborne RES data (Gardner et al, ; Wen et al, ; Yu et al, ). However, the ice discharge estimations from Wen et al (), Rignot et al (), Depoorter et al (), Shen et al (), and Rignot et al () are higher than our results. The most possible reason for the differences is the overestimation of the grounding line ice thickness.…”

“…The higher SMB likely indicates a larger amount of mass gain. Moreover, Shen et al () and Rignot et al () used the long‐term averaged RACMO2.3p1 SMB and obtained a slightly negative mass balance. In contrast, the use of the newer version RACMO2.3p2 SMB will result in a positive mass balance in both studies.…”

“…The Lambert Glacier‐Amery Ice Shelf System (LG‐AIS) is the largest glacial system in East Antarctica (Figure ; Fricker et al, ). It drained more than 60 Gt/year of ice in 2008–2015, which accounts for ~7% of East Antarctica's total ice output (Gardner et al, ; Shen et al, ). LG‐AIS has three large tributary glaciers, the Lambert, Fisher, and Mellor glaciers, which converge at the grounding zone of the Amery Ice Shelf (AIS).…”

“…The Lambert Glacier-Amery Ice Shelf System (LG-AIS) is the largest glacial system in East Antarctica (Figure 1; Fricker et al, 2000). It drained more than 60 Gt/year of ice in 2008-2015, which accounts for 7% of East Antarctica's total ice output (Gardner et al, 2018;Shen et al, 2018a).…”

“…Several studies have been carried out to evaluate the mass balance of the AIS basin, either for individual AIS basins (Wen et al, 2008;Wen et al, 2014;Xie et al, 2016;Yu et al, 2010) or for all of Antarctica, which includes the AIS basin (Gardner et al, 2018;Martin-Espanol et al, 2016;McMillan et al, 2014;Rignot et al, 2008;Rignot et al, 2019;Shen et al, 2018a). Broadly, three different techniques are used to assess ice sheet mass balances (Hanna et al, 2013).…”