Jena 2013 – wissenschaftliches Programm

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UP: Fachverband Umweltphysik

UP 14: Atmosphäre - Spurengase, Aerosole und Labormessungen

UP 14.2: Vortrag

Donnerstag, 28. Februar 2013, 10:15–10:30, HS 5

Formvar replicas of atmospheric ice crystals studied with ESEM — •Alexei Kiselev¹, Martin Schnaiter¹, Paul Vochezer¹, and Carl Schmitt² — ¹Karlsruhe Institute of Technology, Institute for Meteorology und Climate Research — ²National Center for Atmospheric Research, Boulder, Colorado

The method of ice crystal replication in Formvar (polyvinyl acetal 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 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. In this contribution we show what kind of information on the ice crystal morphology and residual particles can be obtained from the formvar replicas of ice particles originated in the AIDA cloud simulation chamber. We demonstrate how the replicas can be analyzed with a modern ESEM and microprobe techniques and compare the images of preserved ice crystals with the forward scattering patterns obtained by the Small Ice Detector, an aircraft optical probe used for the in situ measurements of ice in atmospheric clouds.

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