Reflective Properties of Summer Arctic Sea Ice in Visible and Near Infrared (in English)

Zege E., Malinka A., Katsev I., Prikhach A., Istomina L., Heygster G., Spreen G.

This article presents a brief overview of the recent authors’ works where analytical solutions for the reflection characteristics of summer ice floes with melt ponds in the Visible and near IR have been developed, checked with field experiments and discussed. Sea ice is considered as a statistically homogeneous random mixture of ice, air, and water with a large (in comparison with the light wavelength) scale of inhomogeneities. Within the framework of stereology the inherent scattering characteristics (the attenuation and absorption coefficients, scattering phase functions) of various types of sea ice have been specified analytically. Spectral reflection by ice layers is described within the asymptotic approach of the radiative transfer theory of light propagation in optically thick and comparatively weakly absorbing layers. During melting period the surfaces of ice floes are covered by so called white ice and melt ponds in different proportions. The main factor determining the pond reflection is reflection of its bottom ice. The spectral-angular characteristics of the reflection by both these components (white ice and melt ponds) of Arctic summer ice floes are presented. It is shown that the obtained results are in good agreement with the measurements made in a number of Arctic expeditions, the developed methods of atmospheric correction, which is necessary for processing of both Arctic satellite and field data, being used.

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