Item: WATER RETANTION CURVE OF SNOW FROM X-RAY MICROSTRUCTUER
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Title: WATER RETANTION CURVE OF SNOW FROM X-RAY MICROSTRUCTUER
Proceedings: Proceedings, International Snow Science Workshop, Whistler, BC, Canada, 2026
Authors:
- Satoru Yamaguchi [ National Research Institute for Earth Science and Disaster Resilience, Niigata, Japan ]
- Satoru Adachi [ National Research Institute for Earth Science and Disaster Resilience, Yamagata, Japan ]
- Takafumi Katsushima [ Forestry and Forest Products Research Institute, Niigata, Japan ]
Date: 2026-09-28
Abstract: Because most meltwater movement within a snowpack occurs under unsaturated conditions, the snow water retention curve (SWRC) must be represented appropriately. Conventional SWRC parameterizations are based primarily on snow grain size and density, whereas their relationship to the pore structure that directly controls water retention and drainage remains insufficiently understood. In this study, the three-dimensional pore structure of snow was measured by X-ray micro-computed tomography (X-ray μCT). The pore space was segmented using a three-dimensional watershed method, and an equivalent pore-body diameter distribution was derived from the volume of each segmented pore region. The distribution was fitted with a lognormal function and used to calculate drainage SWRCs with the Kosugi model. The equivalent diameter obtained by the watershed method mainly represents pore-body size, whereas drainage pressure is strongly controlled by the throats connecting adjacent pores. We therefore introduced R_BT, the ratio of pore-body diameter to effective pore-throat diameter, and evaluated the calculated curves against measured SWRCs. With R_BT = 1, the uncorrected model tended to predict drainage at lower suction than observed. Introducing R_BT shifted the characteristic suction scale and improved agreement with the measurements. These results demonstrate the limitation of directly treating watershed-derived equivalent pore-body diameters as capillary-throat diameters and indicate that the size difference between pore bodies and throats should be considered when estimating snow SWRCs.
Object ID: ISSW2026_P2.13.pdf
DOI: https://doi.org/10.15788/1790098908
Language of Article: English
Presenter(s): Satoru Yamaguchi
Keywords: snow water retention curve, equivalent pore-body diameter, X-ray micro-CT, 3D watershed, Kosugi model
Page Number(s): 474 - 478
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