| Project/Area Number |
09680499
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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 | HOKKAIDO UNIVERSITY OF EDUCATION |
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Principal Investigator |
TAKAHASHI Tsuneya Hokkaido University of Education Department of Education Center for Educational Research and Development Associate Professor, 教育学部附属教育実践研究指導センター, 助教授 (60236297)
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| Co-Investigator(Kenkyū-buntansha) |
ENDOH Tatsuo Hokkaido University, Institute of Low Temperature Science Associate Professor, 低温科学研究所, 助教授 (20001844)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 1998: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1997: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | acid snow / gas scavenging / precipitation chemisty / nitric acid vapor / hydrochloric acid vapor / snow particles / snow shape monitoring / 酸性ガス |
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| Research Abstract |
For monitoring shapes of snow particles continuously and automatically, a simple device was developed. Two video cameras with different magnifying powers were used for distinguishing crystal shapes and degrees of riming as well as for distinguishing between aggregates and graupel particles. The visual field areas of the two cameras were 55x42 mm^2 and 9.2x7.0 mm^2, respectively. Snow particles which were collected on a clear Plexiglas disk were blown off by a blower that was operated at constant intervals. A fresh disk surface was then prepared for the next sampling of snow particles.
Observations were carried out from January to March 1998 at Mitoi in a sparsely populated suburban area of Sapporo City. Falling snow particles were collected at intervals of approximately 1 hr. The shapes of snow particles and snowfall intensity were continuously monitored by the above device and a snow gauge using an electric balance, respectively. The concentrations of HCl and HNO_3 vapors in air were measured. It was assumed that these vapors contributed to the acidification of snow particles in riming growth as well as in vapor depositional growth ; but the concentrations of the vapors in air were low at our observation site. Also, it was thought that the vapors were scavenged by snow particles collected on January 1997 at Mosiri in a remote area. It was inferred that that the vapors scavenged by snow particles did not originate in the local urban polluted air but were carried with clouds.
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