Description :
Snow ice (aka: superimposed ice, white ice) results from consecutive flooding and freezing of snow cover. It contains a high density of small (mm-scale) spherical air bubbles that cause volume scattering in C-band. Consequently, snow ice shows green in RADARSAT-2 multi-polarization image composites. At this particular location, the measured total ice thickness was 96 cm, i.e. 10 cm of snow ice underlain by 86 cm of columnar ice. Snow ice is a less desirable base for ice roads than columnar ice because it's bearing capacity is lower by about 50%. As a result of climate warming, the amount of winter rainfall and thus
the expanse of snow ice is expected to increase.
Photographe :
van der Sanden, J J
Collection :
Ressources naturelles Canada
Haute-résolution :
5.83 MB
4928x3264 pixels
300 ppi (jpeg)
Nota :
Depending on the weather conditions, ice cover can grow the full extent of the available water depth and become attached to the lake bottom. Unfortunately, bottom-fast ice cannot be discriminated from floating columnar ice in individual RADARSAT-2 multi-polarization composite images because both ice types display black. Discrimination of the two ice types is facilitated by a times series of RADARSAT-2. The measured backscatter level
decreases when the ice becomes bottom-fast and increases when the ice grows. Similar to shorelines, bottom-fast ice formations jeopardize the trafficability of ice roads because their presence increases the risk of traffic induced ice cover failures. However, the presence of bottom-fast ice is more difficult to ascertain.
Géographie :
5977; Tibbitt-to-Contwoyto Winter Road; Territoires du Nord-Ouest; 2020-344.JPG; Nunavut