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Pre-activation of ice nucleating particles by the pore condensation and freezing mechanism

Wagner, R. ORCID iD icon; Kiselev, A.; Möhler, O.; Saathoff, H. ORCID iD icon; Steinke, I.

Abstract:

In spite of the resurgence in ice nucleation research a comparatively small number of studies deal with the phenomenon of pre-activation in heterogeneous ice nucleation. Already fifty years ago, it was shown that various mineral dust and volcanic ash particles can be pre-activated to become nuclei for ice crystal formation even at temperatures as high as 270–271 K. Pre-activation was achieved under ice subsaturated conditions without any preceding macroscopic ice growth by just temporarily cooling the particles to temperatures below 228 K. A two-step mechanism involving capillary condensation of supercooled water and subsequent homogeneous freezing was proposed to account for the particles' enhanced ice nucleation ability at high temperatures. This work reinvestigates the efficiency of the proposed pre-activation mechanism in temperature-cycling experiments performed in a large cloud chamber with suspended particles. We find the efficiency to be highest for the clay mineral illite as well as for highly porous materials like zeolite and diatomaceous earth, whereas most aerosols generated from desert dust surface samples did not reveal a measurable pre-activation ability. ... mehr


Volltext §
DOI: 10.5445/IR/1000052457
Originalveröffentlichung
DOI: 10.5194/acpd-15-28999-2015
Dimensions
Zitationen: 3
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Meteorologie und Klimaforschung Atmosphärische Aerosolforschung (IMKAAF)
KIT-Zentrum Klima und Umwelt (ZKU)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2015
Sprache Englisch
Identifikator ISSN: 1680-7367
urn:nbn:de:swb:90-524577
KITopen-ID: 1000052457
HGF-Programm 12.01.01 (POF III, LK 01) Clouds in a pertubed atmosphere
Erschienen in Atmospheric Chemistry and Physics Discussions
Verlag European Geosciences Union (EGU)
Band 15
Heft 20
Seiten 28999-29046
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