How much do we need to know about quantitative estimates of microstructure at the snowpit scale? (Invited)
Abstract
In the past about 10 years, new techniques showed that the snowpack is “layered” in a much more complex way than anticipated. Near-infrared photography and high-resolution penetrometry revealed that layers are rarely as distinct and homogeneous as thought. Micro-CT tomography of macroscopic samples several centimeters high with a resolution of 10 μm give us for the first time a continuous view of variability at this scale. For a long time, mostly avalanche researchers were interested in weak layers, the “failure plane” of slab avalanches. Now we see that such a fine layering is not the exception, but rather the rule, except that the “layers” are not so fragile. Density and specific surface area show a large variability often over a scale of few centimeters, in the range of tens of percents of the absolute value. A critical question is how much we have to care about this variability. The answer will be different for different areas. What we clearly see is that we need to incorporate these variations into models simulating the snowpack at high resolution. The reason is that the change in density and structure will change thermal conductivity, which is a key driver of snow metamorphism. Because it will be impossible to sample a snowpack with such high resolution except for a few experiments, we see the challenge to find a stochastic description of this variability. Depending on wavelength, remote sensing applications are influenced by such layers, as well as albedo.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.C22A..05S
- Keywords:
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- 0736 CRYOSPHERE / Snow;
- 0758 CRYOSPHERE / Remote sensing;
- 0794 CRYOSPHERE / Instruments and techniques;
- 0798 CRYOSPHERE / Modeling