Past exam of the mathematics course of the University of Cambridge / 2009 / iii / Paper 77 / 3 / vii / Solution

Open water absorbs more sunlight than bright sea ice, and melt ponds also lower the surface albedo. More absorbed heat promotes further melt and can be stored in the upper ocean, delaying autumn freezing. This ice-albedo feedback amplifies an initially forced loss during the sunlit season. Perovich and collaborators' 2008 measurements identify solar heating of the upper ocean as the main heat source for enhanced bottom melting in their observed Beaufort Sea case. Feedback is especially important locally after open water develops; it does not supply solar heat during polar winter.