Crystal size in accreted ice

✍ Scribed by P. J. Rye; W. C. Macklin

• Book ID: 104574492
• Publisher: John Wiley and Sons
• Year: 1975
• Tongue: English
• Weight: 594 KB
• Volume: 101
• Category: Article
• ISSN: 0035-9009
• DOI: 10.1002/qj.49710142804

✦ Synopsis

Abstract

Studies have been made of the crystallographic orientation of 100μm‐radius supercooled droplets frozen on ice substrates whose c‐axis orientations varied from 0 to 90° to the surface normal. For a given droplet temperature and substrate orientation, there is a critical substrate temperature below which a frozen droplet has a high ( > 0·8) probability of having an orientation which differs from that of the substrate. Above this critical substrate temperature there is a small ( < 0·2) residual probability of reorientation which is dependent on the droplet temperature and substrate orientation but independent of the substrate temperature.

The lengths and maximum widths of ice crystals in accreted ice deposits have also been determined. In the dry growth regime there is a general decrease in the mean length from ∼ 8 to 0·25mm, and in the mean maximum width from ∼ 1 to 0·2mm, as the ambient temperature decreases from − 5 to − 30°C. At ambient temperatures above − 15°C there is no dependence of the crystal dimensions on the temperature of the deposit. At ambient temperatures below this value, the crystal dimensions vary with deposit temperature in a manner consistent with the individual droplet studies. Consequently, measurements of the crystal dimensions in hailstone layers may give useful indications of their growth conditions.