Laboratory Studies of Polarized Light Reflection From Sea Ice and Lake Ice in Visible and Near Infrared

Abstract

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.

Hyperspectral Features of Oil-Polluted Sea Ice and the Response to the Contamination Area Fraction

“…Second, the upper layer of the sea ice melted and reformed, resulting in conditions less air bubbles in the sea ice. According to the research of SUN [ 32 ], less bubble ice has a lower reflectance. The reflectance of crude oil (area fraction 100%) is fairly constant below 1200 nm (the maximum value of reflectance is 0.02 and the minimum value is 0.009).…”

Polarized reflectance factors of vegetation covers from laboratory and field: A comparison with modeled results

“…Because of the limitations of our apparatus, 8° was the smallest phase‐angle measurement that we could obtain when rotating the arm in the viewing direction. NENULGS has been used to detect phase and spectral reflectance curves and the linear polarization degree of snow, soil, and ice when the incident light is unpolarized [ Lv and Sun , ; Sun et al , , ; Sun and Zhao , ; Sun et al , , ].…”

“…We found that the average absolute value of degree of linear polarization of the Spectralon measured by using our instrument was less than 0.01 in the range of 350 nm to 1000 nm; this value was represented as the polarimietric accuracy of our instrument. These parameters were appropriate for studying the polarization of natural surfaces [ Sun and Zhao , ; Sun et al , , ; Suomalainen et al , , ; Peltoniemi et al , ].…”

An assessment of the bidirectional reflectance models basing on laboratory experiment of natural particulate surfaces

“…The NENULGS has been used to detect phase spectral curves of reflectance and degree of linear polarization of snow, soil and ice when the incident light is unpolarized [49][50][51]. A detailed description of the laboratory measurement system is given in [35].…”