WAVY TEMPERATURE DISTRIBUTIONS IN SNOW
The process of heat transfer in snow is important in such fields of snow science as snow avalanches, thermoinsulation by snow in agriculture, permafrost and global energy exchange between the atmosphere and ground in northern regions. Theoretical and experimental results of investigations in this fi...
| Main Authors: | , , |
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| Format: | Report |
| Language: | English |
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ABSTRACT
1997
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| Online Access: | https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=3987 http://id.nii.ac.jp/1291/00003987/ https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3987&item_no=1&attribute_id=18&file_no=1 |
| Summary: | The process of heat transfer in snow is important in such fields of snow science as snow avalanches, thermoinsulation by snow in agriculture, permafrost and global energy exchange between the atmosphere and ground in northern regions. Theoretical and experimental results of investigations in this field have been published by Z. YOSIDA (Contrib. Inst. Low Temp. Sci., 7,19,1955), J. C. GIDDINGS and E. LACHAPELLE (J. Geophys. Res., 67,2377,1962), and Y.-Ch. YEN (J. Geophys. Res., 70,1821,1965). The purpose of such works was mostly determination of numerical values of the heat conductivity and water vapor diffusion coefficient in snow, required for any snow related physical calculations. However, published values of these physical quantities vary over a wide range and are sometimes even not in agreement with theory. The purpose of the present experimental work was to understand the mechanism of simultaneous heat and water vapor transfer in snow by systematic measurements of temperature distributions, density and structure change in snow under an applied temperature gradient. Experimental procedure and results : The experiments on heat and water vapor transfer in snow were done in a cold laboratory of the Institute of Low Temperature Science. The experimental runs were done with naturally compacted snow of density about 350kg・m^<-3> and screened snow of densities from 200 up to 500kg・m^<-3>. Heat and water vapor fluxes were built in snow by sudden heating of one end of sample with initially uniform temperature and maintaining a temperature difference between the opposite ends for a prolonged period of time. The length of a sample was 10,20,30 or 40cm. Fine thermocouples were installed to measure temperatures in several points on the central axis of the sample, parallel to the direction of heat transfer. More details of the experimental set-up and results are reported elsewhere (S. A. SOKRATOV and N. MAENO, Snow Engineering : Recent Advances, ed. by M. IZUMI et al. Rotterdam, Balkema Publ., 49,1997). The ... |
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