Multi-scale satellite observations of Arctic sea ice: new insight into the life cycle of the floe size distribution

Abstract

This study provides a new conceptional framework to understand the life cycle of the floe size distribution of Arctic sea ice and the associated processes. We derived the floe size distribution from selected multi-scale satellite imagery data acquired from different locations and times in the Arctic. Our study identifies three stages of the floe size evolution during summer – ‘fracturing’, ‘transition’ and ‘melt/wave fragmentation’. Fracturing defines the initial floe size distribution ( N  ∼  d −α , where d is floe size) formed from the spring breakup, characterized by the single power-law regime over d  = 30–3000 m with α   ≈  2. The initial floe size distribution is then modified by various floe fragmentation processes during the transition period, which is characterized by ‘selective’ fragmentation of large floes ( d  > 200–300 m) with variable α  = 2.5–3.5 depending on the degree of fragmentation. As ice melt intensifies, the melt fragmentation expands the single power-law regime into smaller floes ( d  = 70 m) with α  = 2.4–3.8, while a significant reduction of small floes ( d  < 30–40 m) occurs due to lateral melt. The shape factor shows an overall progression from elongated floes into rounded floes. The effects of scaling and wave-fracture are also discussed. This article is part of the theme issue 'Theory, modelling and observations of marginal ice zone dynamics: multidisciplinary perspectives and outlooks'.