Japan Geoscience Union Meeting 2018

Presentation information

[JJ] Oral

A (Atmospheric and Hydrospheric Sciences) » A-CC Cryospheric Sciences & Cold District Environment

[A-CC28] Glaciology

Wed. May 23, 2018 10:45 AM - 12:15 PM 106 (1F International Conference Hall, Makuhari Messe)

convener:Takayuki Nuimura(Chiba Institute of Science), Ishikawa Mamoru(Hokkaido University), Kzutaka Tateyama(国立大学法人 北見工業大学, 共同), Hiroto Nagai(Japan Aerospace Exploration Agency), Chairperson:Sunako Sojiro(Graduate School of Environmental Studies, Nagoya University.)

12:00 PM - 12:15 PM

[ACC28-12] Direct observation of elementary steps and quasi-liquid layers on ice surfaces by advanced optical microscopy

*Ken Nagashima1, Gen Sazaki1, Ken-ichiro Murata1, Yoshinori Furukawa1, Tetsuya Hama1 (1.The Institute of Low Temperature Science, Hokkaido University)

Keywords:Ice, Surface melting, Quasi-liquid layer, Molecular step, Advanced optical microscopy

Ice is one of the most abundant crystals on the earth, and hence the molecular-level understanding of ice crystal surfaces holds the key to unlocking the secrets of a number of fields. We and Olympus Engineering Co., Ltd. have developed laser confocal microscopy combined with differential interference contrast microscopy (LCM-DIM), by which we succeeded in the direct visualization of 0.37-nm-thick elementary steps on ice for the first time [1]. Subsequently, the direct observations on ice basal faces revealed the various features of elementary steps [2-4].

On the other hand, we could also visualize the quasi-liquid layers (QLLs) on ice crystal surfaces [5], which are covered with thin liquid layers even below the melting point (0°C). The direct observations of QLLs revealed the appearance of two types of QLLs with different morphologies [5,6], the appearance temperatures and partial pressure of water vapor [6-8], the inducement of the formation of QLLs by strain [9], and the characteristic velocities of QLLs [10].

In addition, we also found that atmospheric acidic gas (hydrogen chloride gas) strongly induced the appearances of droplets on ice surfaces (further details will be presented in "A-AS06: Atmospheric Chemistry" session). The droplets were observed in the temperature range of -15.0 ~ -1.5°C, where no QLL appears in the absence of HCl gas [11]. The HCl induced droplets were embedded into ice crystals by growth of ice crystals [12]. These results show the possibility that ice crystals can store large amount of gas components as fluid inclusions.

[1] Sazaki et al. (2010) PNAS 107, 19702.
[2] Sazaki et al. (2014) Cryst. Growth Des. 14, 2133.
[3] Asakawa et al. (2014) Cryst. Growth Des. 14, 3210.
[4] Inomata et al. (2018) Cryst. Growth Des. 18, 786.
[5] Sazaki et al. (2012) PNAS 109, 1052.
[6] Murata et al. (2016) PNAS 113, E6741.
[7] Asakawa et al. (2015) Cryst. Growth Des. 15, 3339.
[8] Asakawa et al. (2015) PNAS 113, 1749.
[9] Sazaki et al. (2013) Cryst. Growth Des. 13, 1761.
[10] Murata et al. (2015) Phys. Rev. Lett. 115, 256103.
[11] Nagashima et al. (2016) Cryst. Growth Des. 16, 2225.
[12] Nagashima et al., submitted.