ORIGINAL RESEARCH article
Front. Remote Sens.
Sec. Atmospheric Remote Sensing
This article is part of the Research TopicEarth Observations from the Deep Space: 10 Years of the DSCOVR MissionView all 15 articles
Constraining Orientation Statistics of Ice Crystals in Clouds with Observations from Deep Space
Provisionally accepted
- 1Michigan Technological University, Houghton, United States
- 2NASA Goddard Space Flight Center, Greenbelt, United States
- 3University of Maryland, Baltimore County, Baltimore, United States
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Ice crystals in clouds are often modeled as chaotically oriented despite frequent observa-tions of horizontally oriented crystals in-situ and remotely. Zenith-pointing ground-based and nadir-pointing space-borne lidars often encounter intense specular reflections (glints), attributed to horizontally oriented particles (HOPs). When the size and shape of these ice crystals are just right, they appear to fall in precisely horizontal orientation with remarkable accuracy. Here we attempt to constraint the relative contribution, wobbling amplitude and size of HOPs. Although there is an extensive literature on the topic, our discussion renders orientation randomness more precise and includes several additional considerations: (i) deep space optics of the EPIC/DSCOVR observations of angular sizes for cloud glints are brought to bear on the problem; (ii) exponential decay of glint reflectance with angles is observed; (iii) dimensionless moment of inertia constraint is considered to further constrain sizes; (iv) the dependence of air kinematic viscosity ν is introduced into the argument in tandem with the one on the Reynolds number.
Keywords: Ice crystals, Clouds, horizontally oriented particles, Hops, orientation randomness, deep space optics, EPIC/DSCOVR, angular sizes
Received: 14 Sep 2025; Accepted: 20 Nov 2025.
Copyright: © 2025 Kostinski, Marshak and Varnai. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Alex Kostinski, kostinsk@mtu.edu
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