Secondary ice production – no evidence of efficient rime-splintering mechanism
-
Published:2024-05-07
Issue:9
Volume:24
Page:5247-5263
-
ISSN:1680-7324
-
Container-title:Atmospheric Chemistry and Physics
-
language:en
-
Short-container-title:Atmos. Chem. Phys.
Author:
Seidel Johanna S., Kiselev Alexei A.ORCID, Keinert AliceORCID, Stratmann Frank, Leisner Thomas, Hartmann Susan
Abstract
Abstract. Mixed-phase clouds are essential for Earth’s weather and climate system. Ice multiplication via secondary ice production (SIP) is thought to be responsible for the observed strong increase in ice particle number concentration in mixed-phase clouds. In this study, we focus on the rime splintering also known as the Hallett–Mossop (HM) process, which still lacks physical and quantitative understanding. We report on an experimental study of rime splintering conducted in a newly developed setup under conditions representing convective mixed-phase clouds in the temperature range of −4 to −10 °C. The riming process was observed with high-speed video microscopy and infrared thermography, while potential secondary ice (SI) particles in the super-micron size range were detected by a custom-built ice counter. Contrary to earlier HM experiments, where up to several hundreds of SI particles per milligram of rime were found at −5 °C, we found no evidence of productive SIP, which fundamentally questions the importance of rime splintering. Further, we could exclude two potential mechanisms suggested to be the explanation for rime splintering: the freezing of droplets upon glancing contact with the rimer and the fragmentation of spherically freezing droplets on the rimer surface. The break-off of sublimating fragile rime spires was observed to produce very few SI particles, which is insufficient to explain the large numbers of ice particles reported in earlier studies. In the transition regime between wet and dry growth, in analogy to phenomena of the deformation of drizzle droplets upon freezing, we also observed the formation of spikes on the rimer surface, which might be a source of SIP.
Funder
Deutsche Forschungsgemeinschaft
Publisher
Copernicus GmbH
Reference85 articles.
1. Aufdermaur, A. N. and Johnson, D.: Charge separation due to riming in an electric field, Q. J. Roy. Meteorol. Soc., 98, 369–382, https://doi.org/10.1002/qj.49709841609, 1972. a, b 2. Bacon, N. J., Swanson, B. D., Baker, M. B., and Davis, E. J.: Breakup of levitated frost particles, J. Geophys. Res.-Atmos., 103, 13763–13775, https://doi.org/10.1029/98jd01162, 1998. a, b, c 3. Bader, M., Gloster, J., Brownscombe, J., and Goldsmith, P.: The production of sub-micron ice fragments by water droplets freezing in free fall or on accretion upon an ice surface, Q. J. Roy. Meteorol. Soc., 100, 420–426, https://doi.org/10.1002/qj.49710042513, 1974. a, b, c 4. Bigg, E. K.: A new Technique for Counting Ice-Forming Nuclei in Aerosols, Tellus, 9, 394–400, https://doi.org/10.1111/j.2153-3490.1957.tb01895.x, 1957. a 5. Brownscombe, J. L. and Hallett, J.: Experimental and field studies of precipitation particles formed by the freezing of supercooled water, Q. J. Roy. Meteorol. Soc., 93, 455–473, https://doi.org/10.1002/qj.49709339805, 1967. a
Cited by
1 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|