日本地球惑星科学連合2018年大会

講演情報

[EJ] ポスター発表

セッション記号 M (領域外・複数領域) » M-IS ジョイント

[M-IS07] 結晶成長、溶解における界面・ナノ現象

2018年5月23日(水) 15:30 〜 17:00 ポスター会場 (幕張メッセ国際展示場 7ホール)

コンビーナ:木村 勇気(北海道大学低温科学研究所)、三浦 均(名古屋市立大学大学院システム自然科学研究科)、塚本 勝男(大阪大学大学院工学研究科、共同)、佐藤 久夫(三菱マテリアル株式会社エネルギー事業センター那珂エネルギー開発研究所)

[MIS07-P02] 旭岳で光学顕微鏡を用いて観察した雪の結晶の昇華と再成長

*木村 勇気1山﨑 智也1真木 孝雄古川 義純1 (1.北海道大学低温科学研究所)

キーワード:雪、その場観察、干渉計、光学顕微鏡法

To understand characteristic properties of water and its phase transition processes via nucleation and subsequent growth, we performed in-situ observation experiment using real snow crystals at the base of Asahi-dake in the Taisetsu area, Hokkaido, Japan. We stayed there 11 nights in total for four winter seasons from 2015 to 2018 and observed sublimation and regrowth processes of snow crystals using originally designed experimental systems; the Maki-type laser interferometer (modified Mach–Zehnder-type interferometer), the Michelson-type white-light interferometer microscope with a long working distance, the optimized color-filtered optical microscopes, a polarized optical microscope and so on. We also prepared an environment controllable cell using a Peltier cooling unit, which has a water vapor source with a heater and a chromel-alumel thermocouple, windows for optical observation, capillary to handle a snow crystal and a platinum resistance temperature detector for temperature measurement of the cell.

At first, we make one or two igloo-like snow laboratories (snow-lab) and set up optical systems in the snow-lab. Typical ambient temperature in the Taisetsu area is around -10 to -20oC and inside temperature of the snow-lab is slightly increased to be -5 to -11oC due to experimental systems such as illumination lights, monitor and camera in addition to heat of active observers. The humidity has been naturally controlled close to 100% because all the walls of the snow-lab have been made of snow, which also works as a good sound and vibration absorber.

We collected snow crystals directly on a black felt just outside the snow-lab and selected a snow crystal, which was put onto a glass plate for general observations of the shape and surface textures or onto the tip of the glass rod smaller than 1 mm in diameter to observe rates for sublimation and regrowth at a certain environment. Interference fringes made using a reflection light from a surface of a snow crystal were successfully observe by the Michelson-type white-light interferometer microscope. In this presentation, we will report our attempts of in-situ observation and the results including temperature and humidity dependent rates of sublimation and regrowth of a snow crystal observed using our experimental systems.


Acknowledgments: We thank Y. Sato, Y. Hirata, S. Nakatsubo and K. Fujita of the Technical Division in the Institute of Low Temperature Science, Hokkaido University, for their help in the development of the experimental system. This study was supported partly by the Grant for Joint Research Program of the Institute of Low Temperature Science, Hokkaido University and by a Grant-in-Aid for Scientific Research (S) from KAKENHI (15H05731).