Day 4

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Paper title Observations of Ice Velocity on the East Antarctic Ice Sheet with Sentinel-1
  1. Sally Wilson University of Leeds Speaker
  2. Anna E. Hogg University of Leeds, Leeds, UK
Form of presentation Poster
  • A9. Polar Science and Cryosphere
    • A9.04 Mass Balance of the Cryosphere
Abstract text Global sea level rise and associated flood and coastal change pose the greatest climate change risk to low-lying coastal communities. Over the past century, global sea level has risen 1.7 ± 0.3 mm per year on average, although this figure has risen to 3.7 ± 0.5 mm per year between 2006 and 2018 (IPCC AR6), and models predict that this acceleration in global sea level rise is only set to continue. Earth’s ice sheets present a large uncertainty in the global sea level budget, therefore it is vital to monitor ice flow in Antarctica in order to quantify the size and timing of the ice sheet’s contributions to global sea level rise.

Satellite observations have shown that the West Antarctic Ice Sheet is dynamically imbalanced, as ice mass loss from the flow of outlet glaciers is larger than mass gained via snow accumulation. In contrast, East Antarctica is thought to be in either equilibrium or in positive mass balance over the last 20 years (Shepherd et al., 2012), although some regions of localised thinning have been observed (McMillan et al., 2014). Although East Antarctica has contributed 7.4 ± 2.4 mm sea level rise since 1992 (IPCC AR6), the accuracy and thus significance of this ice loss with regards to sea level rise over the last 30 years is uncertain (Rignot et al., 2019). The Lambert Glacier - Amery Ice Shelf drainage basin is one of the largest in East Antarctica, and therefore is important in assessing Antarctica’s present and future sea level contribution.

In this study we present ice velocity measurements from late 2014 to the present day, using intensity feature tracking of Synthetic Aperture Radar (SAR) image pairs acquired predominantly by the Copernicus Sentinel-1 mission. We use 6-day repeat pass Single Look Complex (SLC) SAR images acquired in Interferometric Wide (IW) swath mode from both Sentinel-1a and Sentinel-1b satellites, to investigate ice velocity changes on a weekly timescale. Focused initially on Lambert Glacier in Eastern Antarctica, these ice velocity results are combined with surface and bed topography measurements to determine ice flux, then converted to mass balance using the input-output method, to assess ice mass change over time in Eastern Antarctica.