Day 4

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Paper title Getz on the run: 25 years of mass imbalance in the Getz region West Antarctica
Authors
  1. Heather L Selley University of Leeds Speaker
  2. Anna E. Hogg University of Leeds, Leeds, UK
  3. Stephen L Cornford Swansea University
  4. Pierre Dutrieux British Antarctic Survey
  5. Andrew Shepherd CPOM Leeds
  6. Jan Wuite ENVEO IT GmbH
  7. Dana Floricioiu German Aerospace Center (DLR), Remote Sensing Technology Institute
  8. Anders Kusk DTU Space - Technical University of Denmark
  9. Thomas Nagler ENVEO IT GmbH
  10. Lin Gilbert UCL-MSSL
  11. Thomas Slater University of Leeds
  12. Tae-Wan Kim Korea Polar Research Institute
Form of presentation Poster
Topics
  • A9. Polar Science and Cryosphere
    • A9.04 Mass Balance of the Cryosphere
Abstract text The Getz region is a large, marine-terminating sector of West Antarctica, which is losing ice at an increasing rate; however, the forcing mechanisms behind these changes remain unclear. Despite the area of the Getz Ice Shelf remaining relatively stable over the last 3 decades, strong ice shelf thinning has been observed since the 1990s. The region is one of the largest sources of fresh water input to the Southern Ocean, more than double that of the neighbouring Amundsen Sea ice shelves. In this study we use satellite observations including Sentinel-1, and the BISCILES ice sheet model, to measure ice speed and mass balance of Getz over the last 25-years. Our observations show a mean speedup of 23.8 % between 1994 and 2018, with three glaciers speeding up by over 44 %. The observed speed up is linear and is directly correlated with ice sheet thinning, confirming the presence of dynamic imbalance in this region. The Getz region has lost 315 Gt of ice since 1994 contributing 0.9 ± 0.6 mm to global mean sea level, with an increased rate of ice loss since 2010 caused by a reduction in snowfall. On all glaciers, the speed increase coincides with regions of high surface lowering, where a ~50% speed up corresponds to a ~5% reduction in ice thickness. The pattern of ice speedup indicates a localised response on individual glaciers, demonstrating the value of high spatial resolution satellite observations that resolve the detailed pattern of dynamic imbalance across the Getz drainage basin. Partitioning the influence of both surface mass and ice dynamic signals in Antarctica is key to understanding the atmospheric and oceanic forcing mechanisms driving recent change. Dynamic imbalance accounts for two thirds of the mass loss from Getz over the last 25-years, with a longer-term response to ocean forcing the likely driving mechanism. Consistent and temporally extensive sampling of both ocean temperatures and ice speed will help further our understanding of dynamic imbalance in remote areas of Antarctica in the future. Following this work, 9 of the 14 glaciers in the region have recently been named after the locations of major climate conferences, treaties and reports, celebrating the importance of international collaboration on science and climate policy action.