Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
doi:10.5194/acp-2016-1180
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
31 Jan 2017
Review status
This discussion paper is under review for the journal Atmospheric Chemistry and Physics (ACP).
Uncertainty in counting ice nucleating particles with continuous diffusion flow chambers
Sarvesh Garimella1, Daniel A. Rothenberg1, Martin J. Wolf1, Robert O. David2, Zamin A. Kanji2, Chien Wang1, Michael Roesch1, and Daniel J. Cziczo1,3 1Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
2Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
3Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States
Abstract. This study investigates the measurement of ice nucleating particle (INP) concentration and sizing of crystals using continuous flow diffusion chambers (CFDCs). CFDCs have been deployed for decades to measure the formation of INPs under controlled humidity and temperature conditions in laboratory studies and by ambient aerosol populations. These measurements have, in turn, been used to construct parameterizations for use in models by relating the formation of ice crystals to state variables such as temperature, humidity, and aerosol particle properties such as composition and number. We show here that assumptions of ideal instrument behavior are not supported by measurements made with a commercially available CFDC, the SPectrometer for Ice Nucleation (SPIN), and the instrument on which it is based, the Zurich Ice Nucleation Chamber (ZINC). Non-ideal instrument behavior, which is likely inherent to varying degrees in all CFDCs, is caused by exposure of particles to different humidities and/or temperatures than predicated from theory. This can result in a systematic, and variable, underestimation of reported INP concentrations. We use a machine learning approach to show that non-ideality is most likely due to small scale flow features where the aerosols are combined with sheath flows and to minimize the uncertainty associated with measured INP concentrations. We suggest that detailed measurement, on an instrument-by-instrument basis, be performed to characterize this uncertainty.

Citation: Garimella, S., Rothenberg, D. A., Wolf, M. J., David, R. O., Kanji, Z. A., Wang, C., Roesch, M., and Cziczo, D. J.: Uncertainty in counting ice nucleating particles with continuous diffusion flow chambers, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2016-1180, in review, 2017.
Sarvesh Garimella et al.
Sarvesh Garimella et al.
Sarvesh Garimella et al.

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