Item: Measurement of Dynamic Water-Entry Value for Dry Snow
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Title: Measurement of Dynamic Water-Entry Value for Dry Snow
Proceedings: International Snow Science Workshop, Davos 2009, Proceedings
Authors:
- Takafumi Katsushima [ Nagaoka University of Technology, NagaokaÂcity, Niigata, JAPAN ]
- Satoru Yamaguchi [ Snow and Ice Research Center, National Research Institute for Earth Science and Disaster PreÂvention, NagaokaÂcity, Niigata, JAPAN ]
- Toshiro Kumakura [ Nagaoka University of Technology, NagaokaÂcity, Niigata, JAPAN ]
- Atsushi Sato [ Snow and Ice Research Center, National Research Institute for Earth Science and Disaster PreÂvention, NagaokaÂcity, Niigata, JAPAN ]
Date: 2009
Abstract: In soil physics, many people have discussed about mechanisms of developing preferential flow based on porous media hydraulics. In snow science, there are few studies on the preferential flow though the preferential flow governs a part of runoff process in a snowpack. Dry sand has a water-entry value which is a threshold value of the capillary pressure to start infiltration into dry sand. Water cannot infiltrate in the situation that the capillary pressure at the wetting front is less than the water-entry value. The preferential flow is developed in the upwardnegative gradient of the capillary pressure behind the wetting front, which is appeared in the case that the water-entry value is larger than the capillary pressure along the upper moving path of the wetting front. It is thought that the phenomena on the preferential flow in the sand are almost same as these in the snow and the water-entry value of the homogeneous dry snow layer is important to study the preferential flow in the snowpack. In this study, the water-entry values were obtained by measuring the capillary pressure at the wetting front penetrating into the underlying dry snow. The capillary pressure was measured with the high response tensiometers. The measured water-entry values were greater than the airentry value according to the water retention curve for drying process. The water-entry value with large diameter is larger than one with small. The some paths of the preferential flow were observed in these experiments. On the other hand, the water-entry value was not observed and the preferential flow was not observed in the experiment which used the smaller diameters of snow particles.
Object ID: issw-2009-0248-0251.pdf
Language of Article: English
Presenter(s): Unknown
Keywords: preferential flow, water-entry value, homogeneous dry snow
Page Number(s): 248-251
Subjects: dynamic water-entry value dry snow snowfall measurements
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