A comprehensive laboratory study on the immersion freezing behavior of illite NX particles : a comparison of seventeen ice nucleation measurement techniques

• Main Authors: Hiranuma, Naruki, Augustin-Bauditz, Stefanie, Bingemer, Heinz, Budke, Carsten, Curtius, Joachim, Danielczok, Anja, Diehl, Karoline, Dreischmeier, Katharina, Ebert, Martin, Frank, Fabian, Hoffmann, Nadine, Kandler, Konrad, Kiselev, Alexei, Koop, Thomas, Leisner, Thomas, Möhler, Ottmar, Nillius, Björn, Peckhaus, Andreas, Rose, Diana, Weinbruch, Stephan, Wex, Heike, Boose, Yvonne, DeMott, Paul J., Hader, John D., Hill, Thomas C., Kanji, Zamin A., Kulkarni, Gargi, Levin, Ezra J. T., McCluskey, Christina S., Murakami, Masataka, Murray, Benjamin J., Niedermeier, Dennis, Petters, Markus D., O'Sullivan, Daniel, Saito, Atsushi, Schill, Gregory P., Tajiri, Takuya, Tolbert, Margret A., Welti, André, Whale, Thomas F., Wright, Timothy P., Yamashita, Katsuya
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2014
• Subjects: ddc:550; inuit
• Online Access: http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/37253; https://nbn-resolving.org/urn:nbn:de:hebis:30:3-372536; https://doi.org/10.5194/acpd-14-22045-2014; http://publikationen.ub.uni-frankfurt.de/files/37253/acpd-14-22045-2014.pdf; http://publikationen.ub.uni-frankfurt.de/files/37253/acpd-14-22045-2014-supplement.pdf; http://publikationen.ub.uni-frankfurt.de/files/37253/container.zip

Immersion freezing is the most relevant heterogeneous ice nucleation mechanism through which ice crystals are formed in mixed-phase clouds. In recent years, an increasing number of laboratory experiments utilizing a variety of instruments have examined immersion freezing activity of atmospherically relevant ice nucleating particles (INPs). However, an inter-comparison of these laboratory results is a difficult task because investigators have used different ice nucleation (IN) measurement methods to produce these results. A remaining challenge is to explore the sensitivity and accuracy of these techniques and to understand how the IN results are potentially influenced or biased by experimental parameters associated with these techniques. Within the framework of INUIT (Ice Nucleation research UnIT), we distributed an illite rich sample (illite NX) as a representative surrogate for atmospheric mineral dust particles to investigators to perform immersion freezing experiments using different IN measurement methods and to obtain IN data as a function of particle concentration, temperature (T), cooling rate and nucleation time. Seventeen measurement methods were involved in the data inter-comparison. Experiments with seven instruments started with the test sample pre-suspended in water before cooling, while ten other instruments employed water vapor condensation onto dry-dispersed particles followed by immersion freezing. The resulting comprehensive immersion freezing dataset was evaluated using the ice nucleation active surface-site density (ns) to develop a representative ns(T) spectrum that spans a wide temperature range (−37 °C < T < −11 °C) and covers nine orders of magnitude in ns. Our inter-comparison results revealed a discrepancy between suspension and dry-dispersed particle measurements for this mineral dust. While the agreement was good below ~ −26 °C, the ice nucleation activity, expressed in ns, was smaller for the wet suspended samples and higher for the dry-dispersed aerosol samples between about ...