| Project/Area Number |
12573015
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | TOKAI UNIVERSITY |
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Principal Investigator |
NAGAO Toshiyasu Institute of Oceanic Research & Development, Professor, 海洋研究所, 教授 (20183890)
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| Co-Investigator(Kenkyū-buntansha) |
TANIGUCHI Makoto Nara Univ. of Education ,Dept. of Earth Sci. Professor, 教育学部, 教授 (80227222)
YAMANO Makoto Univ. Tokyo, Earthquake Res. Inst,Associate Professor, 地震研究所, 助教授 (60191368)
SWEDA Tatsuo Ehime University, Faculty of Agriculture,Professor, 農学部, 教授 (90109314)
KINOSHTIA Masataka JAMSTBC,Deep Sea Res. Group,Associate Researcher, 深海研究部, 副主幹 (50225009)
OHKUBO Yasukuni AIST,Geological Survey of Japan, Senior Researcher, 地圏資源環境研究部門, 主任研究官
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥14,900,000 (Direct Cost: ¥14,900,000)
Fiscal Year 2002: ¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 2001: ¥5,200,000 (Direct Cost: ¥5,200,000)
Fiscal Year 2000: ¥5,500,000 (Direct Cost: ¥5,500,000)
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| Keywords | Kamchatka Peninsula / paleoclimate reconstruction / geothermics / borehole temperature / groundwater flow / stable isotopes / dendrochronology / global warming / 気候変動 / 地下温度 / 年輪年代学 / 極東地域 / 古気候 / 地下温度勾配 / カムチャッカ |
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| Research Abstract |
We estimated climate changes in the Kamchatka Peninsula over the last few centuries with two independent, geothermal and dendrochronological methods.
As studies with the geothermal method, we conducted three expeditions in 2000 to 2002 to make repeated measurements of temperature profiles in ten boreholes around 53 degN. The ground surface temperature history could be reconstructed from the temperature profiles in six of the boreholes, demonstrating a significant temperature increase of 1 to 2 K for the last 50 to 100 years. We also made long-tem temperature monitoring at some specific depths in three boreholes and observed temporal variations which suggest the existence of small-scale water convections and seasonal changes in groundwater flow. Groundwater samples were taken from the boreholes where temperature logging was made and surface water samples were also collected from rivers. Geochemical and stable isotope characteristics of the groundwater and surface water were analyzed to e
… More
valuate the effects of the groundwater flow on the subsurface temperature and climate reconstruction in the study areas.
A 422-year long chronology of ring-width indices representing central Kamchatka was established from tree-ring cores sampled from Larix gmerinii growing natural in the Kronotsky National Park in 2001 based on reconnaissance in 2000. Response analysis of the chronology against observed climate revealed a significant correlation with early-summer temperature. The reconstructed temperature extending back to A.D. 1624 based on the dendrochronology and its response to climate, revealed a general warming trend over the last 130 years and a cyclic oscillation of decadal period. The long-term trend is consistent with the result from the borehole temperature profiles.
Reconstruction of the ground surface temperature history from borehole temperature profiles was also made for three wells in Korea and one well on the coast of Lake Biwa. In Korea, the estimated temperature changes are consistent with the air temperature data at nearby meteorological stations. The surface temperature history by Lake Biwa appears to reflect local environmental changes for the last 5000 years. Less
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