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

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 ( ∼ , where is floe size) formed from the spring breakup, characterized by the single power-law regime over  = 30-3000 m with  [Formula: see text] 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 ( > 200-300 m) with variable  = 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 ( = 70 m) with  = 2.4-3.8, while a significant reduction of small floes ( < 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'.