ORIGINAL RESEARCH article
Sizes and shapes of sea ice floes broken by waves - a case study from the East Antarctic coast
- 1Institute of Oceanography, University of Gdansk, Poland
- 2Nansen Environmental and Remote Sensing Center (NERSC), Norway
The floe size distribution (FSD) is an important characteristics of sea ice, influencing several physical processes that take place in the oceanic and atmospheric boundary layers under/over sea ice, as well as within sea ice itself. Through complex feedback loops involving those processes, FSD might modify the short-term and seasonal evolution of the sea ice cover, and therefore significant effort is undertaken by the scientific community to better understand FSD-related effects and to include them in sea ice models. An important part of that effort is analyzing the FSD properties and variability in different ice and forcing conditions, based on airborne and satellite imagery. In this work we analyze a very high resolution (pixel size: 0.3 m) satellite image of sea ice from a location off the East Antarctic coast (65.6°S, 101.9°E), acquired on 16. Feb. 2019. Contrary to most previous studies, the ice floes in the image have angular, polygonal shapes and a narrow size distribution. We show that the observed FSD can be represented as a weighted sum of two probability distributions, a Gaussian and a tapered power law, with the Gaussian part clearly dominating in the size range of floes that contribute over 90% to the total sea ice surface area. Based on an analysis of the weather, wave and ice conditions in the period preceding the day in question, we describe the most probable scenario that led to the breakup of landfast ice into floes visible in the image. Finally, theoretical arguments backed up by a series of numerical simulations of wave propagation in sea ice performed with a scattering model based on the the Matched Eigenfunction Expansion Method, are used to show that the observed dominating floe size in the three different regions of the image (18 m, 13 m and 51 m, respectively) agree with those expected as a result of wave-induced breaking of landfast ice.
Keywords: sea ice, Floe size distribution, sea ice breaking, sea ice-waves interactions, Satellite Imagery, East Antarctic coast
Received: 19 Jan 2021;
Accepted: 04 May 2021.
Copyright: © 2021 Herman, Wenta and Cheng. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Agnieszka Herman, University of Gdansk, Institute of Oceanography, Gdansk, 81-378, Poland, firstname.lastname@example.org