EGU26-20615, updated on 14 Mar 2026
https://doi.org/10.5194/egusphere-egu26-20615
EGU General Assembly 2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
Poster | Tuesday, 05 May, 10:45–12:30 (CEST), Display time Tuesday, 05 May, 08:30–12:30
 
Hall X5, X5.60
A hidden treasure: ice nucleating particles preserved inside formvar replicas of ice crystals can be identified using scanning electron microscopy 
Laura Arnold1, Florian Zanger1, Martin Schnaiter1, Adrian Hamel1, Carl Schmitt2, Andrew Heymsfield3, Heike Wex4, Christopher Fuchs5, Jan Henneberger5, and Alexei A. Kiselev1
Laura Arnold et al.
  • 1Karlsruhe Institute of Technology, IMK, AAF, Germany (laura.arnold@partner.kit.edu)
  • 2Alaska Climate Research Center, Geophysical Institute, University of Alaska, Fairbanks, USA
  • 3NSF NCAR MMM Laboratory, Boulder, Colorado, USA
  • 4Leibniz Institute of Tropospheric Research, Leipzig, Germany
  • 5ETH Zürich, Institute for Atmosphere and Climate Science, Zürich, Switzerland

The method of ice crystal replication in Formvar (polyvinyl formal resin) was introduced by Vincent Schaefer in 1941 [1]. At that time no aircraft based optical instrumentation was available to study the morphology of ice crystals. In spite of the rapid advance of the sophisticated optical particle probes, the formvar replication technique, applied in its very original form, turns out to be a valuable complimentary method for the ice crystal habit characterization [4].

In addition to habit and surface morphology, some formvar replicas preserve residual particles that may have acted as ice nucleating particles (INPs). Early attempts to identify these nuclei (e.g. Kumai, 1951 [2] and Koenig, 1960 [3]) were limited by poor instrumental resolution and lack of accurate elemental analysis. Modern scanning electron microscopy and X-Ray spectroscopic techniques allows us to revisit this approach. The ice nucleating particles preserved within the replicas can be characterized and attributed to the ice crystal habits and sampling environmental conditions. Based on several case studies, including ice nucleation experiments conducted in AIDA chamber and analysis of formvar replicas of ice crystals collected from free atmosphere and by airborne probes, we evaluate the potential of the ice replication method combined with SEM analysis for INP identification.

References:

[1] Schaefer, V. J.: A method for making snowflake replicas. Science, 93 (1941) pp. 239-240.

[2] Kumai, M.: Electron-microscope study of snow-crystal nuclei. J. Atmos. Sci., 8 (1951) pp. 151-156.

[3] Koenig, L. R.: The chemical identification of silver-iodide ice nuclei: a laboratory and preliminary field study. J. Atmos. Sci., 17 (1960) pp. 426-434.

[4] Miloshevich, L. M. and Heymsfield, A. J.: A Balloon-Borne Continuous Cloud Particle Replicator for Measuring Vertical Profiles of Cloud Microphysical Properties: Instrument Design, Performance, and Collection Efficiency Analysis, J. Atmos. and Oceanic Tech., 14 (1997), pp. 753-768.

How to cite: Arnold, L., Zanger, F., Schnaiter, M., Hamel, A., Schmitt, C., Heymsfield, A., Wex, H., Fuchs, C., Henneberger, J., and Kiselev, A. A.: A hidden treasure: ice nucleating particles preserved inside formvar replicas of ice crystals can be identified using scanning electron microscopy , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20615, https://doi.org/10.5194/egusphere-egu26-20615, 2026.