Reflective properties of melt ponds on sea ice
Abstract. Melt ponds occupy a large part of the Arctic sea ice in summer and affect strongly the radiative budget of the atmosphere-ice-ocean system. In this study the melt pond reflectance is considered in the framework of the radiative transfer theory. The melt pond is modeled as a plane-parallel layer of pure water upon a layer of sea ice (pond bottom). The reflection is considered as comprising of Fresnel reflection by the water surface and multiple reflections between the pond surface and its bottom, which is assumed to be Lambertian. Analytical formulas are put forward to calculate the bidirectional reflectance factor (BRF) and the albedo at different incident angles. The effects of the incident conditions and the atmosphere state are examined. The optical model developed is verified with data from in situ measurements made during several field campaigns performed on landfast and pack ice in the Arctic. The comparison to field spectra demonstrates good performance of the developed model for the variety of melt pond types observed in the Arctic.