Abstract
It is well known that heat input at the surface and the thermal properties of the soil control the variations of soil temperature according to time and space. However, observations of soil temperature distribution were not so often made as those of air temperature. The author has investigated the influence of vegetation and snow cover on the soil temperature distribution and its annual variation.
Observation were carried out at the Sugadaira Montane Research Center of the University of Tsukuba in Nagano Prefecture, Central Japan from November 1976 extending over 25 months. Soil temperature of 50cm depth was measured at 34 points beneath grassland vegetation (Miscanthus sinensis Stand) and forest vegetation (Pinus densiflora Stand) using the method of moving observation. The instrument used is the thermister thermometer for soil temperature.
The results of observation indicate that distribution pattern of 50cm depth soil temperature is well coincident with the map of vegetation from May to November. During continuous snow cover period, December to April, it is not accord with the distribution of vegetation. According to disappearence time of snow cover, soil temperature becomes minimum in March or April, while it is maximum in August at all observation points. Just after snowmelt soil temperature begins rising suddenly. Therefore, annual soil temperature variation is affected by snowcover and thaw during snowcoverage season.
