| Project/Area Number |
06452086
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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 |
Meteorology/Physical oceanography/Hydrology
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| Research Institution | Nagoya University |
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Principal Investigator |
ISHIZAKA Yutaka Nagoya University, Insitute for Hydrospheric-Atmospheric Sciences, Associate Progessor, 大気水圏科学研究所, 助教授 (50022710)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1995: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Stratospheric clouds / Freezing of acid droplets / NAT particles / Sulfuric acid droplets / Freezing nuclei / Ozone depletion / Nitric acid / 凍結核 / 成層圏氷晶の凍結核 / 酸性水滴の凍結温度 / 成層圏雲粒子 |
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| Research Abstract |
Freezing points of acid droplets were measured in a cryostat under the stratospheric condition and chemical composition of ice particles formed in a cryostat was determined with an electron microscope using thin-film chemical methods. Acid droplets were suspended on the tungsten wires in the sample holder. Size range of the acid droplets was from 10 to 50 mum in diameter. Sulfuric acid, nitric acid, hydrochloric acid and methanesulfonic acid solutions were used to make acid droplets. Droplets were observed with a CCD camera through the microscope. Freezing temperature of droplets was determined by detecting ice embryos in the droplet. It was found from the experiment that freezing point of sulfuric acid droplets decreased linearly with increasing acid concentration. Freezing point of sulfuric acid droplets with acid concentration of 70%wt was about -80ﾟC.Freezing point of nitric acid droplets did not depend strongly on acid concertration, and it was lower than that of sulfuric acid droplets above 35%wt of acid concentration. Hydrochloric acid droplets froze at lower temperatures than freezing points of sulfuric acid and nitric acid droplets. On the other hand, melting points of ice particles were also measured by increasing temperatures of ice particles after acid droplets froze. Further, some of particles before and after freezing of sulfuric acid particles under the supply of nitric acid and water vapor were sampled on an electron microscope mesh covered with barium chloride and nitron films. NO3- ion was not detected in acid droplets, but it was detected in ice particles. The result indicates that nitric acid vapor can be absorbed in ice particles during their growth after acid droplets froze.
The results of this laboratory experiments strongly suggests that ice and NAT particles can be formed by freezing of sulfuric acid particles in the stratosphere.
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