Preprints
https://doi.org/10.5194/tc-2021-121
https://doi.org/10.5194/tc-2021-121

  20 Apr 2021

20 Apr 2021

Review status: a revised version of this preprint is currently under review for the journal TC.

18 year record of circum-Antarctic landfast sea ice distribution allows detailed baseline characterisation, reveals trends and variability

Alexander D. Fraser1, Robert A. Massom2,1, Mark S. Handcock3, Phillip Reid4,1, Kay I. Ohshima5, Marilyn N. Raphael6, Jessica Cartwright7, Andrew R. Klekociuk2,1, Zhaohui Wang8, and Richard Porter-Smith1 Alexander D. Fraser et al.
  • 1Australian Antarctic Program Partnership, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania 7001, Australia
  • 2Australian Antarctic Division, Channel Highway, Kingston, Tasmania 7050, Australia
  • 3Department of Geography, University of California, Los Angeles, CA 90095, USA
  • 4Bureau of Meteorology, 111 Macquarie St, Hobart, Tasmania 7000, Australia
  • 5Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
  • 6Department of Statistics, University of California, Los Angeles, CA 90095, USA
  • 7Spire Global, Inc., Glasgow, G3 8JU, UK
  • 8Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania 7001, Australia

Abstract. Landfast sea ice (fast ice) is an important though poorly-understood component of the cryosphere on the Antarctic continental shelf, where it plays a key role in atmosphere-ocean-ice sheet interaction and coupled ecological and biogeochemical processes. Here, we present a first in-depth baseline analysis of variability and change in circum-Antarctic fast-ice distribution (including its relationship to bathymetry), based on a new high-resolution satellite-derived time series for the period 2000 to 2018. This reveals a) an overall trend of −882 ± 824 km²/y (−0.19 ± 0.18 %/y); and b) eight distinct regions in terms of fast-ice coverage and modes of formation. Of these, four exhibit positive trends over the 18 y period and four negative. Positive trends are seen in East Antarctica and in the Bellingshausen sea, with this region claiming the largest positive trend of +1,198 ± 359 km²/y (+1.10 ± 0.35 %/y). The four negative trends predominantly occur in West Antarctica, with the largest negative trend of −1,206 ± 277 km²/y (−1.78 ± 0.41 %/y) occurring in the Victoria and Oates Lands region in the eastern Ross Sea. All trends are significant. This new baseline analysis represents a significant advance in our knowledge of the current state of both the global cryosphere and the complex Antarctic coastal system that is vulnerable to climate variability and change. It will also inform a wide range of other studies.

Alexander D. Fraser et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on tc-2021-121', Gregory Leonard, 03 Jun 2021
    • AC1: 'Reply to RC1', Alexander Fraser, 27 Aug 2021
  • RC2: 'Comment on tc-2021-121', Anonymous Referee #2, 30 Jul 2021
    • AC2: 'Reply to RC2', Alexander Fraser, 27 Aug 2021

Alexander D. Fraser et al.

Alexander D. Fraser et al.

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Short summary
Landfast ice is sea ice that remains stationary by attaching to Antarctica’s coastline and grounded icebergs. Although a variable feature, landfast ice exerts influence on key coastal processes involving pack ice, the ice sheet, ocean and atmosphere, and is of ecological importance. We present a first analysis of change in landfast-ice over an 18 y period, and quantify trends (−0.19 ± 0.18 %/year). This analysis forms a reference of landfast ice extent and variability for use in other studies.