Vertical structure in convective clouds producing graupels and snowflake aggregates

• Main Authors: Hiroyuki Konishi, Tatsuo Endoh, Gorow Wakahama
• Format: Report
• Language: English
• Published: Osaka Kyoiku University 1989
• 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=3562; http://id.nii.ac.jp/1291/00003562/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3562&item_no=1&attribute_id=18&file_no=1

This paper describes the vertical air motion and evolution of snow particles in snow clouds that bring heavy snowfall to the north-east coast of the Sea of Japan in winter. The vertical winds are investigated in detail by single Doppler radar and by simultaneous measurement of particle diameter and fall velocity at the radar site. Graupels were formed near the cloud top where updraft was prevailing; they fell in the downdraft region below the cloud base. The downdraft was probably produced by drag force of falling graupels. On the other hand, aggregates grew slowly in comparatively weak updrafts between the cloud top and the ground. When the cloud top was high and the number concentration of the particles was large, the ratio of large aggregates increased because particles aggregate themselves while falling a long distance.