Interaction of sea ice floe size, ocean eddies, and sea ice melting

The effect of the horizontal size of sea ice floes on sea ice melting is commonly formulated using the ratio between side and basal floe area. This leads to the conclusion that floe size is not important for sea ice evolution when floes exceed about 30 m. This paper considers a mutual interaction between floe size, ocean circulation, and melting. We find that lateral density gradients form at the boundaries of floes and drive ocean‐mixed‐layer instability and energetic eddies that spread from the ice edge. The resulting circulation mixes heat horizontally, melting floes near their edges. Idealized ocean model experiments show that the sea ice response is sensitive to floe size in the range of 1–50 km, considerably larger than previously assumed important, as smaller floes melt more rapidly per unit ice area. It is proposed that the role of eddies and floe size distribution should be incorporated into current climate models.