The effects of grain size on bidirectional polarized reflectance factor measurements of snow

The linear polarization of light reflected from snow surfaces was measured by an instrument composed of a semi-automatic goniometer and an ASD spectroradiometer under a direct lamp to determine its potential to detect differences in grain size. The Stokes parameters were computed for all snow samples. The results confirmed that the degree of polarization increased in bright bands and decreased in dark bands with an increase in grain size. The trend was more obvious in the near-infrared bands and in the forward direction. As the snow grain size varied the contribution of Q parameter to the degree of polarization was more than the U parameter, which was slight. Our results confirmed that the degree of polarization may be useful to distinguish the snow grain size. All above measurements were carried out in the laboratory where the atmospheric contribution was ignored.

► In this paper we measured the multi-angle hyperspectral polarization of snow. ► We described the distribution of degree of polarization in the forward direction. ► We analyzed the effects of grain size on the snow optical properties. ► The wavelength and angle dependence of the degree of polarization are found. ► The degree of polarization may be useful to distinguish the snow grain size.