Day 4

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Paper title Ice velocity measurements in the Amundsen Sea Sector of West Antarctica using Sentinel-1, from late 2014 to 2021
  1. Ross Slater 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 Ice loss from Antarctica and Greenland has caused global mean sea level to rise by more than 1.8 cm since the 1990’s, and observations of mass loss are currently tracking the IPCC AR5’s worst-case model scenarios (Slater et al., 2020). Satellite observations have shown that ice loss in Antarctica is dominated by ice dynamic processes, where mass loss occurs on ice streams that speed up and subsequently thin, such as in the Amundsen Sea Embayment in West Antarctica. Here this thinning and the related retreat of ice sheet grounding lines has been recorded since the 1940’s, and is driven by the advance of warm modified Circum-polar Deep Water onto the continental shelf which melts the base of the floating ice shelves. This incursion is linked to atmospheric forcing driven by the El Niño-Southern Oscillation (ENSO). Ice velocity observations can be used in conjunction with measurements of thickness and surface mass balance to determine ice sheet mass balance. This is essential as the ice sheet contribution to the global sea level budget remains the greatest uncertainty in future projections of sea level rise (Robel et al., 2019), driven in part by positive feedbacks such as the Marine Ice Sheet Instability (MISI). Both long term and emerging new dynamic signals must be accurately measured to better understand how ice sheets will change in the future, and consistent records from satellite platforms are required to separate natural variability from anthropogenic signals (Hogg et al., 2021).

In this study we present measurements of ice stream velocity Amundsen Sea sector of West Antarctica. Our results cover the whole operational period of Sentinel 1, from 2014 onwards, and are determined using intensity feature tracking on pairs of Level 1 Interferometric Wide (IW) swath mode Single Look Complex (SLC) Synthetic Aperture Radar (SAR) images from both the Sentinel 1 A and B satellites. We show that during the study period ice speeds have changed on a number of glaciers in the study region, including Pine Island Glacier, demonstrating the critical importance of continuous, near-real-time monitoring from satellites.

Slater, T., Hogg, A.E. & Mottram, R. (2020) Ice-sheet losses track high-end sea-level rise projections. Nat. Clim. Chang. 10, 879–881; DOI: 10.1038/s41558-020-0893-y

Robel, A.A., Seroussi, H. & Roe, G.H. (2019) Marine ice sheet instability amplifies and skews
uncertainty in projections of future sea-level rise P.N.A.S. 116 (30); DOI: 10.1073/pnas.1904822116

Hogg, A.E., Gilbert, L., Shepherd, A., Muir, A.S. & McMillan, M. (2021) Extending the record of Antarctic ice shelf thickness change, from 1992 to 2017. A.S.R.; DOI: 10.1016/j.asr.2020.05.030