STUDY ON PERIGLACIAL PHENOMENA AND ENVIRONMENTS IN THE ALPINE ZONE OF JAPAN

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Observations of air and ground temperature and wind speed and direction were carried out in the alpine zone of Japanese high mountains, the Daisetsuzan Mountains, Mt.Yoteizan and Mt.Rishirizan in Hokkaido, northern Japan, and Mt.Sugorokudake and Mt.Minamidake in central Japan. The results are summarized as follows.1. the Daisetsuzan MountainsThe air temperatures at the wind-blown bare sites and at the forest line of 1,700m a.s.l. showed that the upper part of the Daisetsuzan Mountains belongs to a discontinuous permafrost zone and moreover to the alpine zone. The mean wind speed at the wind-blown site from October to April exceeds 10 m/s, and the prevailing wind direction is WNW.In autumn the lowest ground temperature is recorded in the Pinus pumila community, characterizing the upper part of Japanese high mountains, among all the plant communities. This indicates that the Pinus pumila community creates a peculiar environment for the ground temperature regime in summer.2. Mt.Yoteizan a … More nd Mt.RishirizanThe air temperatures at the wind-blown sites near the summits of Mt.Yoteizan (1,898m a.s.l.) and Mt.Rishirizan (1,719m a.s.l.) indicated that the climatic conditions of both sites corresponds to that of discontinuous permafrost zone. But a permafrost has not been confirmed through a ground temperature observation or a boring research.3. Mt.Sugorokudake and Mt.MinamidakeThe air and ground temperatures were observed at the wind-blown sites near the summits of Mt.Sugorokudake (2,860m a.s.l.) and Mt.Minamidake (3,033m a.s.l.). There is a difference in the altitude between the both mountains, but the conspicuous difference in the air temperature condition is not recognized between the two. The air temperatures indicated that there is a permafrost in the wind-blown bare ground near the summits. Permafrost, however, did not recognized through the ground temperature observation on Mt.Sugorokudake. On Mt.Minamidake, more observation and research are required to confirm that there is a permafrost or not. Less