HR: 1330h
AN: H22D-0953    [PDF]
TI: Determining the Snow Depth Distribution on a Mountain Slope Using an Airborne Laser Scanner
AU: * Okamoto, T
EM: okataka@ffpri.affrc.go.jp
AF: Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki, 305-8687 Japan
AU: Kurokawa, U
EM: ushio@ffpri.affrc.go.jp
AF: Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki, 305-8687 Japan
AU: Matsuura, S
EM: matsu03@ffpri.affrc.go.jp
AF: Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki, 305-8687 Japan
AU: Asano, S
EM: shiho03@ffpri.affrc.go.jp
AF: Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki, 305-8687 Japan
AB: In heavy snow districts in Japan, snow cover makes slopes more unstable. For example, the snow load affects the normal stress and the snow glide affects the shear stress of the slope. Furthermore, snow thaws in spring and changes into meltwater, which increases the pore water pressure in the ground. To understand quantitatively the effect of snow cover on slope stability, the distribution of snow depth must be obtained. However, it has conventionally been estimated by multi-point measurement only by a probe pole with low plane resolution. In this study, we used an airborne laser scanner both during the snow period and non-snow period to measure both surface elevations. We determined the snow depth distribution by calculating the difference in each value with high accuracy and high resolution. The scanned area is located near the west coast of Japan. The scanning slope has an area of 18 ha and elevation of 500 m to 700 m above sea level. In midwinter, this area is normally covered with snow up tp 3 - 4 m depth. The scanning was conducted in February 2003 for the snow period and in May 2003 for the non-snow period. The calculated snow depth was 2.3 m on average. However, snow depths of more than 4 m or less than 1 m sometimes appeared, showing that the snow cover was not uniformly distributed on the mountain slope. Furthermore, our research revealed the following characteristics of the distribution. 1) The snow depth on a north-facing slope is larger than that on a south-facing slope, which we consider to be the result of the difference in solar radiation between the slopes. 2) The snow depth is less on a steep slope near the mountaintop and ridge, and is larger between the contour line where the slope gradient changes from steep to gentle. This is thought to be because snow is blown off by the wind or that snow drifts are formed.
DE: 1800 HYDROLOGY
DE: 1863 Snow and ice (1827)
DE: 1884 Water supply
SC: Hydrology [H]
MN: 2003 Fall Meeting