1994 Fiscal Year Final Research Report Summary
Experimental study on the micro-physical process of ozone-hole depression by ice crystals in PSC
| Project/Area Number |
05455001
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
広領域
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
FURUKAWA Yoshinori HOKKAIDO UNIV.ILTS.LOW TEMPERATURE SCIENCE,ASSOCIATE PROFESSOR, 低温科学研究所, 助教授 (20113623)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Ozone hole / Polar stratosheric cloud / Ice crystals / Ellipsometry / Second harmonic generation / Molecular dynamics simulation / Surface transition layr / Fluorocarbon |
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| Research Abstract |
1. Ozone-hole depression in the stratospheric atmosphere is enhanced by the ice crystals which are formed in the Polar Stratospheric Cloud (PSC). In order to measure the decomposition rate of ozone molecules on the ice crystal surfaces, an experiment was carried out using a newly developed chamber, which was combine with the optical detectors for the ice surface structures, such as an ellipsometer and a Surface Second Harmonic Generation (SSHG). specially, the SSH signal was first detected from the ice crystal surface, which was prepared by the negative-crystal method and molecularly flat. As a result, we claim that it was made possible to carry out the quantitative measurements for the decomposition rate of ozone molecules on the ice crystal surfaces.
2. The physical process of the decomposition of ozone molecules on the ice crystal surfaces relates to the ice surface structures in molecular-level. A molecular dynamics simnlation for the ice surface was carried out in the wide temperature range. As a result, a thin transition layr with the disordered arrangement of water molecules was detected. Water molecules in such the transition layr may react to the HCl or CIONO_2 molecules, which are formed by the decomposition of fluorocarbon molecules in the stratosheric atmosphere. On the other hand, the molecular dynamics simulation for the ice/water (namely, ice/transition layr) interface also was carried out and we found the anisotropic properties for the difference of crystallographic orientations. This result means that the activity of ice crystals for the decomposition of ozone molecules may depend on the ice crystal shape.
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