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In this paper, the design and operation of the Northeast Normal University Laboratory Goniospectrometer System for performing multi-angular reflected and polarized measurements under controlled illumination conditions is described. A semi-automatic arm, which is carried on a rotated circular ring, enables the acquisition of a large number of measurements of surface Bidirectional Reflectance Factor (BRF) over the full hemisphere. In addition, a set of polarizing optics enables the linear polarization over the spectrum from 350 nm to 2300 nm. Because of the stable measurement condition in the laboratory, the BRF and linear polarization has an average uncertainty of 1% and less than 5% depending on the sample property, respectively. The polarimetric accuracy of the instrument is below 0.01 in the form of the absolute value of degree of linear polarization, which is established by measuring a Spectralon plane. This paper also presents the reflectance and polarization of snow, soil, sand, and ice measured during 2010-2013 in order to illustrate its stability and accuracy. These measurement results are useful to understand the scattering property of natural surfaces on Earth.

As the knowledge of polarized reflection from ice may be important for understanding radiative transfer in ice and be of potential value in imaging applications, spectral reflectances and linear polarization of sea ice and lake ice have been measured in visible and near infrared (NIR) (350-2500 nm) at nadir and the specular direction, respectively. Results are presented for three ice types: 1) black lake ice (bubble-free ice); 2) lake ice with air bubbles; and 3) sea ice with brine pockets but no air bubbles. The effects of air bubbles and brine pockets on spectral reflectance and degree of linear polarization (DLP) are investigated in ice of 0.15 m thick at −20 • C. Spectral reflectances are sensitive to ice condition, consistent with earlier studies of lake ice and sea ice. The DLP of ice in the specular reflection direction is found to be inversely but nonlinearly proportional to reflectance. The case of 1) polarized clearly more light than 2) or 3) in visible wavelength, but they were similar in NIR wavelength, implying the significant contribution of polarization derived from specular reflection. Apparent changes are predicted as volume scattering from air bubbles and brine pockets play an important role in decreasing the DLP of ice in the specular direction.Index Terms-Degree of linear polarization (DLP), lake ice, optical properties, sea ice.

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