抄録
The objective of this research is to compile soil temperature data of surface soils (5 cm depth) for 11 years from 2001 to 2011, and to find new knowledge about soil temperature of Mt. Rishiri. Six points at different altitudes were selected as research sites, ranging from 25 m above sea level at the foot of Mt. Rishiri to 1410 m above sea level near the summit. Data logger type thermometers were buried at the depth of 5 cm in the soils in 6 sites, and soil temperature was measured once every hour. From these data, we calculated analytical values such as the daily average soil temperature, the monthly average soil temperature, and the daily range. The most distinctive feature was that at low altitude sites, the insulation and heat retention effect of snowfall worked in the winter, and the daily and monthly average soil temperatures remained stable around 0 °C. On the other hand, at high altitude sites, the number of days with average daily soil temperature below 0 °C exceeded 50%. It was found that the soils at these two locations were frozen for more than half of the year. In addition, the reference temperature was set to 0 °C, 5 °C, 10 °C, and 15 °C, and the effective cumulative temperature, which was the cumulative value of the time and temperature exceeding each temperature, was calculated, and the rate of change with respect to altitude was calculated depending on the difference in the standard temperature. I confirmed that there is a big difference.
