Publication Date:
2018-08-28
Description:
Noctilucent clouds are thin ice clouds that appear around the summer polar mesopause. Recently, the Cloud Imaging and Particle Size instrument on the AIM satellite discovered nearly circular ice free regions within the clouds—denoted as “ice voids.” The origin of these ice voids is not known. Their existence has so far only been reported by Cloud Imaging and Particle Size, which only can give very limited information of the time scales involved. On 4 July 2010, such an ice void was registered by our ground-based camera taking images with 30-s time interval. We thus here present the first full temporal development of an ice void. Surprisingly, the void did not drift with the prevailing wind as cloud features around it, but instead remained notably stationary for its entire existence of approximately 1 hr. This indicates that that the origin is of stationary character, rather than a rapid change of the local atmosphere. ©2018. American Geophysical Union. All Rights Reserved.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
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