Status: this preprint was under review for the journal ESSD. A final paper is not foreseen.
A 3D map of englacial attenuation rate from radar reflections at
Law Dome, East Antarctica
Syed Abdul Salam,Jason L. Roberts,Felicity S. McCormack,Richard Coleman,and Jacqueline A. Halpin
Abstract. The East Antarctic Ice Sheet (EAIS) is the largest source of potential sea-level rise, containing approximately 52 m of sea-level equivalent. To constrain estimates of sea-level rise into the future requires knowledge of ice-sheet properties and geometry and ice-penetrating radar offers a means to estimate these properties (e.g. ice thickness, englacial temperatures). One of the regions that have been extensively surveyed using ice-penetrating radar from the Investigating the Cryospheric Evolution of the Central Antarctic Plate (ICECAP) project in East Antarctica is Law Dome, a small independent ice cap situated to the west of Totten Ice Shelf. The ice cap is slow-moving, has a low melt-rate at the surface and moderate wind speeds, making it a useful study site for estimating the radar attenuation. A new method is proposed for the estimation of attenuation rate from radar data which is mathematically modelled as a constrained regularised l2 minimisation problem. In the proposed method, only radar data is required and the englacial reflectors are automatically detected from the radar data itself. To validate our methodology, attenuation differences at flight crossover points are calculated and statistical analyses performed to assess the accuracy of the results. For spatial analyses, the errors are of the order 22.6 %, 15.2 %, and 32.8 % for mean absolute error, median absolute error, and root mean square error respectively. Also, for the depth analyses, up to the depth of 800 m, the errors are under 29.9 %, 24.2 %, and 38.8 % for mean absolute error, median absolute error, and root mean square error respectively. A final product of 3D attenuation rates and uncertainty estimates is provided. The generated dataset is publicly available at https://doi.org/10.25959/5e6851e266f4a (Abdul Salam, 2020).
This preprint has been withdrawn.
Received: 08 Jun 2020 – Discussion started: 27 Oct 2020
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Syed Abdul Salam,Jason L. Roberts,Felicity S. McCormack,Richard Coleman,and Jacqueline A. Halpin
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A 3D map of englacial attenuation rate from radar reflections at Law Dome, East AntarcticaSyed Abdul Salam, Jason L. Roberts, Felicity S. McCormack, Richard Coleman, and Jacqueline A. Halpin https://doi.org/10.25959/5e6851e266f4a
Syed Abdul Salam,Jason L. Roberts,Felicity S. McCormack,Richard Coleman,and Jacqueline A. Halpin
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Latest update: 05 Dec 2024
Syed Abdul Salam
Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
Accurate estimates of englacial temperature and geothermal heat flux are incredibly important
for constraining model simulations of ice dynamics (e.g. viscosity is temperature-dependent) and sliding. However, we currently have few direct measurements of vertical temperature (i.e. only at boreholes/ice domes) and geothermal heat flux in Antarctica. This method derives attenuation rates, that can then be mapped directly to englacial temperatures and geothermal heat flux.
Accurate estimates of englacial temperature and geothermal heat flux are incredibly...