1986 Fiscal Year Final Research Report Summary

Alpine Permafrost Occurrence at High Mountain Area in Hokkaido

Research Project

Project/Area Number	60580194
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	自然地理学
Research Institution	Institute of Low Temperature Science, Hokkaido University
Principal Investigator	FUKUDA Masami Institute of Low Temperature Science, Hokkaido Univ., Associate Prof, 低温科学研究所, 助教授 (70002160)
Project Period (FY)	1985 – 1986
Keywords	Alpine Permafrost / Discontinous Permafrost / Permafrost Table / Soil-Wedge Polygon / Active Layer / 活動層 / 森林限界 / 山岳永久凍土
Research Abstract	Author reports the existence of alpine permafrost at Mt. Taisetu which locates at the central Hokkaido in northern Japan. The locations of permafrost occurrence are flat summits above timber line limits (1500m) and no vegerations are covered on the ground surgace there. Continuous monitoring of ground temperature profiles give the mean annual temperature gradients in soil layers. The extra-interpolation of temperature gradient to the frozen layers indicates the permafrost table is located at 550 cm depth. Active frost cracks on the ground surface were observed on the flat summits. The increase of the width of open mouth of cracks were recorded as 1 cm. No ice was filled in the cracks. The palsas were formed at the area where considerable depth of peat was deposited. Freeze-thaw cycles in active layers resulted in formations of sorted circles and other sorted features on the ground surface.

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