Melt pond distributions in Arctic summer 2008 were investigated based on analyses of aerial photographs obtained during the 3rd Chinese National Arctic Research Expedition. Melt ponds were the dominant features on ice surface during most of the cruise. Analyses on the size of isolated pond indicated an abundance of relative small ponds. Pond size distribution showed a nice fit to the power law, but a difference between ponds on first-year ice and multiyear ice can be observed. Pond shape analysis revealed a uniform fractal dimension of pond edge but a variable roundness, implying the geometrical complexity of melt ponds.
The sea ice cover of the Arctic Ocean experiences a dramatic change in the surface characteristics during summer. Surface melting, which starts in early June and ends in early September, making the meltwater collect in sharply delineated ponds on the undulating or hummocked surface of multiyear ice or in shallow depressions on the surface of first-year ice (Fetter and Untersteiner, 1998). This change on the ice surface promotes a positive ice-albedo feedback (Curry, 1995; Tucker et al., 1999) in which the melting decreases the surface albedo, leading to more solar radiation that is absorbed by ice, which causes further melting and reductions in albedo. The overall reduction of Arctic sea ice extent and thickness, especially in recent years, has been proven to be enhanced partly by the ice-albedo feedback mechanisms (Liu et al., 2007; Pedersen et al., 2009), thus making urgent requests on a thorough understanding of melt ponds. In addition to the important roles of melt ponds playing in the surface heat budget, surface melting also affects the accuracy of ice concentration determined from satellite microwave sensors because passive microwave data cannot distinguish melt ponds from true open water (Meier, 2005; Inoue et al., 2008).
