MORPHOLOGY OF CRYSTALS IN FREE FALL AT TEMPERATURES BETWEEN 0 AND -4℃

• Main Authors: タカハシ チュウジ, タケウチ マユミ, キムラ レミ, Chuji TAKAHASHI, Mayumi TAKEUCHI, Remi KIMURA
• Format: Report
• Language: English
• Published: ABSTRACT 1997
• Subjects: Polar meteorology and glaciology; Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=3991; http://id.nii.ac.jp/1291/00003991/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3991&item_no=1&attribute_id=18&file_no=1

Ice crystals were grown in free fall by using a large cloud chamber of height 6.5m. Nucleation was carried out by introducing a piece of dry ice in a supercooled cloud produced in the chamber. Ice crystals fell in a supercooled cloud and were collected at the bottom of the chamber. Circular disc crystals grew at temperatures above -1℃. Their size was about 50μm in diameter and about 5μm in thickness. At temperatures about -2℃, hexagonal plates with a lunar pattern grew. It was observed that these patterns were formed by the step growth on basal faces. Circular disc crystals with {(112)^^^-0} crystal faces were observed. It was estimated that these {(112)^^^-0} crystal faces appeared during the growth process from circular discs to hexagonal plates. They disappeared because of their slow growth rate, after forming small hollows on their faces.