A study on snow distribution in high elevations above the forest line using airborne laser scanning
Abstract
In cold and snowy regions, the snowmelt water is essential to meet the water demand. It is very important to estimate snow depth distribution in mountain regions as accurately as possible. However at high elevations above the forest line, it is particularly difficult to set snow survey points according to the risk of avalanches. In recent years, the acquisition of high-density three-dimensional spatial data for wide areas has become possible by using airborne laser scanning. We conducted airborne laser scanning twice, in 2012 and in 2015, to measure the snow depth in the same range in mountainous regions. A purpose of the study was how wind affects the snow depth distribution at high elevations based on measurements done for two years in the same range.The surveys were conducted in the Chubetsu Dam basin. It's located in Hokkaido, northern part of Japan. The range of airborne laser scanning was 10km2 and at elevations between 1,100m and 2,300m. The forest line in the survey area is at the elevation of about 1,450m. The airborne laser scanning was conducted from September 22 to 25, 2009 (during the snow-free period), on March 10, 2012 and on March 27, 2015 (during the snowy period). The snow depth was calculated as the difference between the elevation in the period with snow and that in the period without snow.The snow depth distribution is strongly affected by wind at higher elevations above the forest line. To analyze how wind affects snow depth distribution, we divided a forest area and a high-elevation area into 16 orientation zones each, and we calculated the average snow depth for each zone. The snow depth is nearly evenly distributed in the forest area in 2012 and 2015. In contrast, the snow depth distribution above the forest line shows greater snow depths in the ranges between northeast and southeast than in the ranges between northwest and southwest in 2012 and 2015. Strong winds that can transport snow tend to be westerly when winter storms occur on the Sea of Japan side of Hokkaido including the survey area. We can assume that these westerly winds blow snow and cause uneven snow depth distributions in high elevations.Using airborne laser scanning that measured the snow depths in 2012 and in 2015, made a detailed analysis of how wind affects the snow depth distribution at high elevations above the forest line.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.C33B0791N
- Keywords:
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- 0758 Remote sensing;
- CRYOSPHERE