Instruments
POSSSUM (Profile Of Snow Specific Surface Area Measurement Using SWIR reflectance) measures profiles of specific surface area (SSA, a metrics of the grain size) in snow boreholes with a vertical resolution of 1 cm and up to depths of ~ 20 m. The SSA is deduced from the snow reflectance (albedo) in the short wave infrared (SWIR) at 1310nm. It takes less than an hour to sample a 10 m deep hole! POSSSUM was tested and validated in the Alps (Arnaud et al. 2011) and was used in Antarctica at Dome C from Dec 2009 and on the logistics and ASUMA traverses.- ASSSAP 1 & 2 (Alpine/Arctic Snow Specific Surface Area) is a light-weight version of POSSSUM designed for the shallow snowpacks (max 2 m) usually found in Alpine and Arctic regions.
ASSSAP uses exactly the same principle of measurement as POSSSUM and allows in addition measurements on snow samples like DUFISSS/IceCube. ASSSAP has extensively been used in Antarctica, Greenland, and in the Alps. During the Davos Intercomparison campaign we have confirmed that the accuracy is as good as other technique in sample mode (10%) and still very good in profile mode (15%). Considering that it takes 10 min to acquire a 1-m profile, ASSSAP is a very efficient method to get accurate SSA and sample the spatial variability.
- RLS (Rugged Laser Scan ) is an automatic laserscan designed to work at Dome C, even in winter by -80°C.
It scans an area of 150m2 every day and allow monitoring snow accumulation, roughness change, sastrugi dynamics and more. Four devices are currently built, RLS1 has been runnning Dome C since Jan 2015 (Picard et al. 2016). RLS2 was one season at Col du Porte for testing (Picard et al. 2016) and two seasons at Col du Lac Blanc to investigate sastrugi development in collaboration with F. Naaim, H. Bellot. RLS3 device has been running at Col de Porte in a clear-cut in a pine forest to investigate snow &s; vegetation interactions (M. Sicart). RLS4 is being deployed at Umuijaq in Canada in the framework of the Acceleration of Permafrost Thaw By Snow-Vegetation Interactions project (F. Dominé).
- Autosolexs is an automatic multi-channel spectrometer with home-made high-accuracy cosine collectors.
AutosolexsDMC has been running at Dome C since Dec 2012 (Libois et al. 2015, Picard et al. 2016, see also data). It is composed of two heads with up- and down-looking channels and fibers embedded in the snowpack. AutosolexsCdP is a similar device installed at Col de Porte in 2012-2013 and 2013-2014 (Dumont et al. 2017, see also data) and at Col du Lautaret (2016-2017) for the ANR EBONI (M. Dumont) and ESA S3 SNOW projects.
- Solexs is an optical instrument to measure the profile of irradiance in snow. This profiles can be related to snow microstructure (Libois et al. 2014), ice absorption (Picard et al. 2016), impurities (Tuzet et al. 2019) and in vegetation (Brea-Belke et al. in review) depending on the processing and the type of snowpack. It allows very fast measurements which is interesting by itself to assess the spatial variability but also from a more quantitative point of view when exploited in complement to other microstructure like SSA or density.