Day 4

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Paper title Mapping the grounding lines of Greenland's floating ice tongues using high-resolution digital elevation models
Authors
  1. Laura Melling Lancaster University Speaker
  2. Malcolm McMillan Lancaster University
  3. Jenny Maddalena Lancaster Environment Centre, Lancaster University
  4. Amber Leeson Lancaster Environment Centre, Lancaster University
  5. Jade Bowling Lancaster Environment Centre, Lancaster University
Form of presentation Poster
Topics
  • A9. Polar Science and Cryosphere
    • A9.04 Mass Balance of the Cryosphere
Abstract text Here, we present early results from a new approach to mapping the grounding lines (GLs) of the Greenland ice sheet's (GrIS) floating ice tongues, using high-resolution digital elevation models (DEMs).
Greenland's floating ice tongues represent a key interface through which the ice sheet interacts with its surrounding oceanic and atmospheric environment. The grounding line, which is defined as the juncture between grounded and floating ice, is a key parameter in ice sheet research, and an essential component of multiple previous studies which have focused on ice tongue supraglacial lake dynamics, sediment transport, and vulnerability to climate change. Reliable and precise knowledge of the GL location is fundamental to understanding the geometry and evolution of these sensitive components of the ice sheet, yet is notoriously difficult to accurately measure.
In previous research, GLs have been estimated using techniques such as terrestrial radar interferometry, interferometric synthetic aperture radar, and digital elevation modelling. Compared to recent datasets and techniques, the spatial resolution and temporal sampling of these methods are relatively low, with most exhibiting a spatial resolution of > 25 metres and infrequent return periods. These factors limit the precision with which the GL can be estimated and introduce uncertainty relating to the stability of present-day ice tongues. As a result, current knowledge and research is often reliant upon GLs that have been delineated decades earlier, despite the wide understanding that GLs have the potential to rapidly migrate during the intervening period.
This research, which is associated with ESA's Polar+ 4DGreenland study, aims to exploit a new generation of high-resolution DEMs to improve the spatial precision and temporal record of GL evolution for all GrIS ice tongues, thereby improving our understanding of GL migration. In this presentation we will provide an overview of the method, early results, and expected avenues for further research.