Title Scanning electron microscopy and molecular dynamics of surfaces of growing and ablating hexagonal ice crystals
Author Pfalzgraff, W.C.; Hulscher, R.M.; Neshyba, S.P.
Author Affil Pfalzgraff, W.C., University of Puget Sound, Tacoma, WA
Source Atmospheric Chemistry and Physics, 10(6), p.2927-2935, . Publisher: Copernicus, Katlenburg-Lindau, International. ISSN: 1680- 7316
Publication Date 2010
Notes In English. Published in Atmospheric Chemistry and Physics Discussions: 1 October 2009, http://www.atmos-chem-phys- discuss.net/9/20739/2009/acpd-9-20739- 2009.html ; accessed in May, 2011. 36 refs. GeoRef Acc. No: 310084
Index Terms ablation; climate; clouds (meteorology); crystal growth; crystals; ice; ice crystals; nucleation; temperature; time factor; water vapor; cirrus clouds; clouds; crystal form; crystal systems; crystallization; hexagonal system; Miller- Bravais indices; molecular dynamics; SEM data; surface textures
Abstract We present the first clearly resolved observations of surfaces of growing and ablating hexagonal ice crystals using variable-pressure scanning electron microscopy. The ice surface develops trans- prismatic strands, separated from one another by distances of 5-10 Ám. The strands are present at a wide range of supersaturations, but are most pronounced at temperatures near the frost point. Pyramidal facets consistent with Miller-Bravais indices of 101╗1, and possibly also 202╗1, are associated with ice growth under these conditions. A molecular- dynamics model of a free-standing ice Ih nanocolumn containing 8400 water molecules does not develop trans-prismatic strands, suggesting these features originate at larger spatial or temporal scales. The possible relevance of these surface features to cirrus ice is discussed.
URL http://www.atmos-chem-phys.net/10/2927/2010/acp-10-2927-2010.pdf
Publication Type journal article
Record ID 65006769