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

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

Abstract (englisch):
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. 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 meas ... mehr

Zugehörige Institution(en) am KIT Institut für Meteorologie und Klimaforschung - Atmosphärische Aerosolforschung (IMK-AAF)
Publikationstyp Zeitschriftenaufsatz
Jahr 2016
Sprache Englisch
Identifikator DOI: 10.5194/acp-16-2025-2016
ISSN: 1680-7316
KITopen ID: 1000053446
HGF-Programm 12.01.02; LK 01
Erschienen in Atmospheric Chemistry and Physics
Band 16
Heft 4
Seiten 2025-2042
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