Energy Balance Variation on the Snow Surface during the Snow Covered Season in the Norikura Highland, Japanese Alpine Area

Abstract

In this study, the characteristics of snowmelt in the Norikura highland were investigated using an energy balance analysis to calculate the amount of snowmelt. Meteorological observations were conducted on the Norikura highland (1590m a.s.l.) and an energy balance analysis was carried out on the snow surface during the snow cover seasons. The result showed that multi-year datasets of meteorological observations revealed characteristics such as low air temperature and vapor pressure, and weak wind speed. Throughout each season of snow cover averaged net radiation, the sensible heat flux and latent heat flux were 88.9%, 16.4% and －6.3% energy ratio to the total snowmelt energy, respectively. Each day, conditions were classified as rainy or non-rainy. The result for rainy conditions showed that net shortwave radiation decreased, while net longwave radiation increased greatly. Latent heat and sensible heat flux also increased. Although there was little precipitation heat flux, larger snowmelt energy was provided when it rained. In the late snowmelt period, the snowmelt rate calculated from the energy balance analysis was compared to the observed value, and the two were almost consistent.