2005 Fiscal Year Final Research Report Summary
INDIRECT EFFECT OF AEROSOLS ON GLOVAL COOLING
| Project/Area Number |
14048201
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
OHTA Sachio HOKKAIDO UNIVERSITY, GRADUATE SCHOOL OF ENGINEERING, PROFESSOR, 大学院工学研究科, 教授 (00100058)
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| Co-Investigator(Kenkyū-buntansha) |
MURAO Naoto HOKKAIDO UNIVERSITY, GRADUATE SCHOOL OF ENGINEERING, ASSOCIATE PROFESSOR, 大学院工学研究科, 助教授 (00190869)
YAMAGATA Sadamu HOKKAIDO UNIVERSITY, GRADUATE SCHOOL OF ENGINEERING, ASSISTANT PROFESSOR, 大学院工学研究科, 助手 (80220242)
SANO Itaru KINKE UNIVERSITY, DEPARTMENT OF SCIENCE AND ENGINEERING, 理工学部, 講師 (10247950)
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| Project Period (FY) |
2002 – 2005
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| Keywords | Indirect effect of aerosols / Cloud formation by aerosols / Vertical shaft / Real scale experiment / Ammonium sulfate aerosol / Sodium chloride aerosol / Modal radius of cloud droplets / Number concentration of cloud droplets |
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| Research Abstract |
For evaluation of indirect effects of aerosol particles on climate, field experiments, named with Magic Monkey Project (MMP), were carried out in Artificial Cloud Experimental System (ACES) established in an abandoned vertical shaft with 430m depth in Kamaishi Mining Co. in Iwate pref., Japan. The experiments evaluating the influence of the number concentration of (NH4)2SO4/NaC1 aerosol particles on the properties of resulting cloud droplets were performed in November every year from 2002 to 2005.
At the top of ACES there were two fans which made updraft inside ACES at the maximum 1.4[m/sec]. In the ACES any favorable altitude for measurement are accessible by ladders settled from the bottom to the top. Cloud droplets were visible around 30m above the bottom. Aerosol particles of ammonium sulfate and sodium chloride were generated at the bottom of ACES by atomizers into the air. According to the results obtained in the preliminary experiments intense measurements were carried out between the bottom and the altitude of 100m from there. Cloud droplets were sampled by impactors at several altitudes.
Inside ACES the temperature is very stable around 13.0 degree Celsius at the bottom. Temperature profiles in the ACES showed that temperature lapse rates were small around 30-50m above the bottom of ACES where cloud generation started. When aerosol particles, such as ammonium sulfate and sodium chloride, were generated at the bottom, the number concentration of cloud droplets increased and their diameter decreased keeping the amount of liquid water contents almost constant.
Among the parameters influenced to change the climate, the indirect effect of aerosol is the one with largest uncertainty. Although the results obtained here are envisioned to be used in a general circulation model (GCM), we can not use those result directly. The procedure to modify the obtained results for GCM model was also considered.
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Research Products
(36 results)
