Abstract
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 February 16, 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 discuss the most probable scenarios 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 Matched Eigenfunction Expansion Method are used to show that the observed dominating floe size in the three different regions of the image (18, 13 and 51 m, respectively) agree with those expected as a result of wave-induced breaking of landfast ice.
Highlights
Sea ice floe size distribution (FSD) has attracted increasing attention of sea ice researchers in recent years
Since the pioneering paper of Rothrock and Thorndike (1984), several studies devoted to the analysis of FSD in observational data have been published in 2000s (e.g., Inoue et al, 2004; Toyota et al, 2006; Lu et al, 2008; Steer et al, 2008) and many more have been conducted within the last decade
We present an analysis of sea ice floes visible in a very high resolution optical satellite image acquired on February 16, 2019 over an area located off the Knox Coast in East Antarctica, north of Cape Elliot, between the Mill Island to the west and Bowman Island to the east (Figure 1)
Summary
Sea ice floe size distribution (FSD) has attracted increasing attention of sea ice researchers in recent years. Spatial resolution of a given image (e.g., Toyota et al, 2006; Steer et al, 2008; Gherardi and Lagomarsino, 2015; Toyota et al, 2016; Wang et al, 2016) All those features suggest a long deformation history–in granular materials, rounded shapes and a wide size distribution of grains are a signature of grinding under combined shear and compressive stress. Method (MEEM; Kohout et al, 2007; Kohout and Meylan, 2008), are used to show that the observed dominating floe sizes in the three different regions of the image (18, 13 and 51 m, respectively) agree with those expected as a result of waveinduced breaking of landfast ice. The structure of the paper is as follows: Section 2 contains a description of the analyzed satellite image and the method of floe identification (Section 2.1), as well as a list of other, auxiliary data sources (Section 2.2).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
