Transmission of solar radiation through the snow cover on floating ice

Abstract

Spectral measurements of solar radiation in the band 400-900 nm were performed above and inside the snowpack in two locations in Finland, using a spectroradiometer. The transmittance and extinction coefficient were estimated for different snow layers. Four small candle-shaped photosynthetically active radiation (PAR) sensors were also used to measure the transfer of PAR inside the snowpack. In addition to the light measurements, physical characterization of snow stratigraphy was done, including the thickness, density, hardness (hand test), salinity, and grain size and shape (photographs of crystals). The transmittance varied from <1% (0-12 cm layer) to 80% (0-4 cm layer), and the extinction coefficient was between 0.03 cm-1 (4-8cm layer) and 0.8 cm-1 (0-4 cm layer). The physical properties of the snow varied considerably between locations and days. The density of the snow varied between 140 and 480 kgm-3.