1999 Fiscal Year Final Research Report Summary
Interal Distribution of Acid Material within Snow Crystals
| Project/Area Number |
09680510
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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 |
Environmental dynamic analysis
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| Research Institution | University of Shiga Prefecture |
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Principal Investigator |
FUSHIMI Hirogi Univ. of Shiga Pref. Fac. Environ. Sci., Prof., 環境科学部, 教授 (10109358)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAMURA Toshiyaki Univ.of Shiga Pref. Fac.Environ.Sci., Assist., 低温科学研究所, 助手 (50091434)
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| Project Period (FY) |
1997 – 1999
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| Keywords | acidification / acid shock / CT scanner / snow crystal / warm metamorphism / 融解・再凍結 / 融雪 / 酸性化予測 |
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| Research Abstract |
We found that the river water turns out to be acid not only in the first stage but also in the later stage of snowmelt season in Japan, which differs from the so called acid shock reported to occur in the first stage of the sonwmelt in the northern Europe.
The acid shocks depend on the regional characteristics of the melt-refreeze processes forming the internal distribution of acid materials within snow crystals. In a warm climatic region like the southern Japan, there are possibilities to have the complicated distribution structure of acid materials within granular snows due to the repeated melt-refreeze processes for a long period under the warm metamorphism. Consequently, the pH value of melt water does not always increase as the snowmelt proceeds.
Then, we clarified the microscopic distribution structure of acid materials within snow crystals by using the X-ray computed tomography (CT scanner) that the domains with the acid materials do also exist in the inner parts of snow crystals. So, the acidification of the river water occurs even in the later stage of the snowmelt, when the acid materials concentrates in the inner part of snow crystals.
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