RECONSTRUCTION OF ALEUTIAN LOW ACTIVITIES FOR THE LAST 200 YEARS BY ICE CORE ANALYSES
| Project/Area Number |
09640517
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Meteorology/Physical oceanography/Hydrology
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| Research Institution | THE INSTITUTE OF LOW TEMPERATURE SCIENCE |
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Principal Investigator |
SHIRAIWA Takayuki HOKKAIDO UNIV., THE INSTITUTE OF LOW TEMPERATURE SCIENCE, INST., 低温科学研究所, 助手 (90235739)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Noriyuki HOKKAIDO UNIV., GRADUATE SCHOOL OF ENVIRONMENTAL EARTH SCIENCE, ASSOCIATE PROFESSOR, 地球環境科学研究科, 助教授 (10261348)
KODAMA Yuji HOKKAIDO UNIV., THE INSTITUTE OF LOW TEMPERATURE SCIENCE, INST., 低温科学研究所, 助手 (70186708)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1999: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1998: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1997: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | ice core / Paleoclimate / Kamchatka / Aleutian low / カムチャツカ / 気候変化 / ロシア |
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| Research Abstract |
Reconstruction of the Aleutian low activity was attempted by means of physical and chemical analyses of ice cores recovered from Ushkovsky Ice Cap, Kamchatka, Russia. Major ions and stable oxygen and hydrogen isotopes were measured for the upper 60 m of the ice cores. We found that NaィイD1+ィエD1, KィイD1+ィエD1, MgィイD12+ィエD1, CaィイD12+ィエD1, ClィイD1-ィエD1, and SOィイD24ィエD2ィイD12-ィエD1 are definitely influenced by volcanic activities because high peaks in these ions were observed at the same horizons where visible ash layers are present. In contrast, variations in NOィイD23ィエD2ィイD1-ィエD1 seem to be independent from volcanic ashes except for major volcanic event The fluctuations found in NOィイD23ィエD2ィイD1-ィエD1 are quasi-synchronous to those observed in stable oxygen and hydrogen isotopes which are known to fluctuate seasonally.
By counting seasonallity in NOィイD23ィエD2ィイD1-ィエD1 and stable isotopes, ice core was converted into time series of annual mass balances after compensation with densification and thinning by flow. We found a signiricant positive correlation between reconstructed mass balances and total annual precipitation recorded at foot slope of the Ushkovsky volcano for the last 70 years This implies that the ice core is the proxy of annual precipitation in this area and provide proxy precipitation record for the last 500 years once the whole record (212 m) will be analyzed in future. It will be also possible for this ice cores to show DICE events since the major climate shift observed around mid-1970s in North Pacific Ocean is clearly recorded in the reconstructed mass balances as increasing precipitation.
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Report
(4 results)
Research Products
(13 results)
