| Project/Area Number |
59460215
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
自然地理学
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| Research Institution | TOKYO METROPOLITAN UNIVERSITY (1986)
Hokkaido University (1984-1985) |
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Principal Investigator |
KADOMURA HIROSHI PROF., FACULTY OF SCIENCE, TOKYO METROPOLITAN UNIVERSITY, 理学部, 教授 (80087064)
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| Co-Investigator(Kenkyū-buntansha) |
FUKUDA MASAMI ASS. PROF., LOW TEMPERATURE SCIENCE INSTITUTE., HOKKAIDO UNIVERSITY, 低温科学研究所, 助教授 (70002160)
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| Project Period (FY) |
1984 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 1986: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1985: ¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1984: ¥3,100,000 (Direct Cost: ¥3,100,000)
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| Keywords | Cold Regions / Hokkaido / Holocene / Climatic Change / Vegetation History / Geomorphic Event / Permafrost / 降水パターン |
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| Research Abstract |
THE OBJECT OF THIS PROJECT IS TO GATHER BASIC CLIMATOLOGICAL, HYDROLOGICAL, CRYOPEDOLOGICAL, GEOMORPHOLOGICAL, AND ECOLOGICAL DATA USED FOR RECONSTRUCTING EARLY HOLOCENE ENVIRONMENTAL CHANGES IN COLD REGIONS OF NORTHERN JAPAN, IN PARTICULAR HOKKAIDO. THE MAJOR RESULTS ARE AS FOLLOWS:
1) A PALYNOLOGICAL ANALYSIS OF URYUNUMA MIR CORES SHOW THAT THE RETURN OF HEAVY SNOWFALL OVER THE JAPAN SEA-SIDE AREAS OCCURRED AT C.7000 YR B.P., LEADING TO INCREASED SEDIMENT SUPPLY INTO THE MIR.
2) IN THE KONSEN UPLAND, EAST HOKKAIDO VALLEY HEADS BEGAN TO EXTEND AT C.8000 YR B.P. WITH INCREASED RUNOFF THAT PROBABLY RELATED WITH INCREASED SUMMER PRECIPITATION.
3) FROM THE INTERPRETATION OF HOKKAIDO-WIDE DATA ON FOSSIL PERIGLACIAL FEATURES, SHORT BUT RATHER COLD EPISODES HAVE BEEN ASSUMED AT 1000-9000 YR B.P., C.4000 YR B.P., AND 4000-3000 YR B.P.
4) IN THE DAISETSU MOUNTAINS, A MATHEMATICAL MODEL FOR ANNUAL TEMPERATURE FLUCTUATION SUGGESTS THAT THE ACTIVE LAYER OF PERMAFROST THAT EXSISTS THERE IS 1 M DEEP AND THAT FROST FISSURES ARE BEING FORMED UNDER THE PRESENT CLIMATIC CONDITIONS.
5) IN NORTHERN JAPAN, THE FIRST SIGN OF POSTGLACIAL-MODE CLIMATES APPEARED BETWEEN 13000-12000 YR B.P. WHILE INSTANTANEOUS RESPONSES OF SLOPE PROCESSES TO THIS CHANGE ARE WELL RECOGNIZED, THOSE OF RIVERS WERE LARGELY RETARDED AND RIVER DOWNCUTTING HAS BEEN ACCELERATED SINCE 10000-8000 YR B.P. IN MOST OF VALLEYS.
6) DURING 11000-8000 YR B.P., IN THE R. TOYOHIRA BASIN, SIMULTANEOUS OCCURRENCE OF LARGE-SCALE MASS MOVEMENTS AND VIGOROUS DOWNCUTTING ON THE UPPER REACHES AND RAPID GROWTH OF THE SAPPORO ALLUVIAL FAN IS A MOST LIKELY EVENT.
7) THESE ENHANCED GEOMORPHIC CHANGES SEEMS TO BE CAUSED BY INTENSIFIED SUMMER RAINFALL RELATED WITH TYPHOONS OR TROPICAL CYCLONES AS IN THE PRESENT-DAY. EARLY HOLOCENE CLIMATE RECONSTRUCTION AND MODELLING CALL FOR FURTHER RESEARCH.
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