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A new method for operating a continuous-flow diffusion chamber to investigate immersion freezing: assessment and performance study

Kulkarni, Gourihar; Hiranuma, Naruki; Möhler, Ottmar; Höhler, Kristina; China, Swarup; Cziczo, Daniel J.; DeMott, Paul J.

Glaciation in mixed-phase clouds predominantly occurs through the immersion-freezing mode where ice-nucleating particles (INPs) immersed within supercooled droplets induce the nucleation of ice. Model representations of this process currently are a large source of uncertainty in simulating cloud radiative properties, so to constrain these estimates, continuous-flow diffusion chamber (CFDC)-style INP devices are commonly used to assess the immersion-freezing efficiencies of INPs. This study explored a new approach to operating such an ice chamber that provides maximum activation of particles without droplet breakthrough and correction factor ambiguity to obtain high-quality INP measurements in a manner that previously had not been demonstrated to be possible. The conditioning section of the chamber was maintained at -20 degrees C and water relative humidity (RHO conditions of 113 % to maximize the droplet activation, and the droplets were supercooled with an independently temperature-controlled nucleation section at a steady cooling rate (0.5 degrees C min(-1)) to induce the freezing of droplets and evaporation of unfrozen droplets. The performance of the modified compact ice chamber (MCIC) was evaluated using four INP species: K-feldspar, illite-NX, Argentinian soil dust, and airborne soil dusts from an arable region that had shown ice nucleation over a wide span of supercooled temperatures. ... mehr

Verlagsausgabe §
DOI: 10.5445/IR/1000128188
Veröffentlicht am 08.01.2021
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Meteorologie und Klimaforschung - Atmosphärische Aerosolforschung (IMK-AAF)
Institut für Meteorologie und Klimaforschung (IMK)
KIT-Zentrum Klima und Umwelt (ZKU)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 1867-8548
KITopen-ID: 1000128188
HGF-Programm 12.01.01 (POF III, LK 01) Clouds in a pertubed atmosphere
Erschienen in Atmospheric measurement techniques
Verlag Copernicus Publications
Band 13
Heft 12
Seiten 6631–6643
Vorab online veröffentlicht am 09.12.2020
Schlagwörter Ice nucleation Ice-nucleating particles CFDC instrument
Nachgewiesen in Scopus
Web of Science
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