Description :
Columnar ice (aka: secondary ice, thermal ice, black ice) is typically free of dielectric discontinuities and generates limited backscatter as a results of surface scattering at the ice-water boundary. Consequently, it shows black in this RADARSAT-2 multi-polarization composite image. Relative to other ice types, columnar ice offers superior bearing capacity which obviously benefits ice road trafficability. At this particular location, the measured ice thickness was about 99 cm.
Photographe :
van der Sanden, J J
Collection :
Ressources naturelles Canada
Haute-résolution :
5.9 MB
3696x2448 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 :
6049; Tibbitt-to-Contwoyto Winter Road; Territoires du Nord-Ouest; 2020-341.JPG; Nunavut