Formation processes of sea ice floe size distribution in the interior pack and its relationship to the marginal ice zone off East Antarctica

• Published in: Deep Sea Research Part II: Topical Studies in Oceanography
• Main Authors: Toyota, Takenobu, Kohout, Alison, Fraser, Alexander D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier
• Subjects: Sea-ice; Floe size distribution; Ice melting; Scale invariance; Antarc*; Antarctica; East Antarctica; Sea ice
• Online Access: http://hdl.handle.net/2115/67364; https://doi.org/10.1016/j.dsr2.2015.10.003

To understand the behavior of the Seasonal Ice Zone (SIZ), which is composed of sea-ice floes of various sizes, knowledge of the floe size distribution (FSD) is important. In particular, FSD in the Marginal Ice Zone (MIZ), controlled by wave-ice interaction, plays an important role in determining the retreating rates of sea-ice extent on a global scale because the cumulative perimeter of floes enhances melting. To improve the understanding of-wave-ice interaction and subsequent effects on FSD in the MIZ, FSD measurements were conducted off East Antarctica during the second Sea Ice Physics and Ecosystems eXperiment (SIPEX-2) in late winter 2012. Since logistical reasons limited helicopter operations to two interior ice regions, FSD in the interior ice region was determined using a combination of heli-photos and MODIS satellite visible images. The possible effect of wave-ice interaction in the MIZ was examined by comparison with past results obtained in the same MIZ, with our analysis showing: (1) FSD in the interior ice region is basically scale invariant for both small- (< 100 m) and large- (> 1 km) scale regimes; (2) although fractal dimensions are quite different between these two regimes, they are both rather close to that in the MIZ; and (3) for floes < 100 m in diameter, a regime shift which appeared at 20-40 m in the MIZ is absent. These results indicate that one role of wave-ice interaction is to modulate the FSD that already exists in the interior ice region, rather than directly determine it. The possibilities of floe-floe collisions and storm-induced lead formation are considered as, possible formation processes of FSD in the interior pack. (C) 2015 Elsevier Ltd. All rights reserved.