Exploring snow optical properties with a RoX

When we think to snow, we suddenly imagine a white and bright mantle covering the mountains, and possibly someone skiing on it. Nevertheless, the snow is much more.

It plays a fundamental role in the water cycle and in the availability of water downstream, in the valleys and finally in the plains. This water is used for agriculture, and essential for it. In Europe, the Alps are playing a major role in the snow storage. Unfortunately, the European Alps are located close to one of the most industrialized areas of the planet and they are 3.000 km far from the largest desert of the Earth. The Alps location makes them subjected to many depositions of pollutants (e.g. black carbon) and Saharan dust at the same time. The combination of these impurities falling together with the snow makes this white mantle less white and less bright than we can imagine. A recent publication by Di Mauro et al, shows how the effect of Saharan dust events affect the snowmelt, anticipating the complete snow melt of approximately 1 month..

A technique which recently has been applied for monitoring the impurities on snow and ice is field spectroscopy. On this purpose, a RoX system was installed in 2017 at the experimental site of Torgnon (Aosta Valley, Italy) at 2400 m a.s.l.

Torgnon experimental site

The site is managed by the Regional Environmental Protection Agency (ARPA Val d’Aosta) which is actively collaborating with the remote sensing lab of the university of Milano Bicocca (LTDA). Since then it continuously monitors the snowpack in winter, and the grassland during summertime

The RoX, simply powered by a small solar panel, is collecting every minute spectra of the snow reflectance and it has been used by researchers to track the optical changes due to impurities, such as Saharan dust, algae bloom and air pollution. Thanks to the dust and bird protection systems manufactured by JB Hyperspectral Devices, the upward looking channel is kept clean all the time, even during snowstorm during winter.

Dust and bird protection system preventing the deposition of dust and snow on the cosine receptor looking up

We hope to give you an update of the researcher’s findings soon so far some preliminary results are reported in the following image.

Preliminary results. Courtesy of Biagio Di Mauro (Unimib). Left panel: RoX relectance collected during 3 days above snow with different impurities concentration. Right panel: time seires of RoX derived optical indices.