Day 4

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Paper title Antarctic ice-shelf advance driven by anomalous atmospheric and sea-ice circulation
Authors
  1. Frazer Christie Scott Polar Research Institute, University of Cambridge Speaker
  2. Toby Benham Scott Polar Research Institute, University of Cambridge
  3. Christine Batchelor School of Geography, Politics and Sociology, University of Newcastle, UK
  4. Wolfgang Rack Gateway Antarctica, University of Canterbury
  5. Aleksandr Montelli Scott Polar Research Institute, University of Cambridge, UK
  6. Julian Dowdeswell Scott Polar Research Institute, University of Cambridge, UK
Form of presentation Poster
Topics
  • A9. Polar Science and Cryosphere
    • A9.04 Mass Balance of the Cryosphere
Abstract text The disintegration of the eastern Antarctic Peninsula’s Larsen A and B ice shelves has been attributed to regional-scale atmosphere and ocean warming, and increased mass-losses from the glaciers once restrained by these ice shelves have increased Antarctica’s total contribution to sea-level rise. Abrupt recessions in ice-shelf frontal position presaged the break-up of Larsen A and B, yet, in the ~20 years since these events, documented knowledge of frontal change along the entire ~1,400 km-long eastern Antarctic Peninsula is limited. Here, we show that 85% of the seaward ice-shelf perimeter fringing this coastline underwent uninterrupted advance between the early 2000s and 2019, in contrast to the two previous decades. These observations are derived from a detailed synthesis of historical (including DMSP OLS, ERS-1/2, Landsat 1-7, ENVISAT) and new, high temporal repeat-pass (Landsat 8, Sentinel-1a/b, Sentinel-2a/b) satellite records. By comparing our observations with a suite of state-of-the-art ocean reanalysis products, we attribute this advance to enhanced ocean-wave dampening, ice-shelf buttressing and the absence of sea-surface slope-induced ice-shelf flow, all of which were enabled by increased near-shore sea ice driven by a Weddell Sea-wide intensification of cyclonic near-surface winds since c. 2002. Collectively, our observations demonstrate that sea-ice change can either safeguard from, or set in motion, the final rifting and calving of even large Antarctic ice shelves.