A mechanism that produces dichotomy in melt pond coverage in sea ice floes
Predrag Popović and Dorian S. Abbot
Department of Geophysical sciences, University of Chicago, Hinds Geophysical Sciences, 5734 S. Ellis Ave., Chicago, IL 60637
Received: 14 Jan 2016 – Accepted for review: 15 Feb 2016 – Discussion started: 29 Feb 2016
Abstract. Late in the melt season, sea ice floes in the Arctic have been observed to exhibit a large range in melt pond coverage, from heavily ponded to almost pond free. Some of these observations are consistent with a bimodal distribution in pond coverage with few intermediately ponded ice floes. We present a model for the evolution of melt ponds on sea ice floes in which conservation of hydrostatic balance in response to melt creates an unstable fixed point in pond coverage: if the initial pond coverage is below a threshold value the floe becomes unponded, and if it is above the threshold the floe becomes heavily ponded. Whether the fixed point is physically realistic depends on the differential melting rates of different points on the ice: ice at the perimeter of ponds needs to melt sufficiently slower than bare ice on average. Interestingly, this shows that the melting behavior of the narrow boundary between bare ice and melt ponds can govern the melt pond evolution of the entire ice floe. Since melt pond coverage is one of the key parameters controlling the albedo of sea ice, understanding the mechanisms that control the distribution of pond coverage will help us improve large-scale model parameterizations and sea ice forecasts in a warming climate.
Popović, P. and Abbot, D. S.: A mechanism that produces dichotomy in melt pond coverage in sea ice floes, The Cryosphere Discuss., doi:10.5194/tc-2016-7, in review, 2016.