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| Titel |
The Leipzig Ice Nucleation chamber Comparison (LINC): An overview of ice nucleation measurements observed with four on-line ice nucleation devices |
| VerfasserIn |
Monika Kohn, Heike Wex, Sarah Grawe, Susan Hartmann, Lisa Hellner, Paul Herenz, André Welti, Frank Stratmann, Ulrike Lohmann, Zamin A. Kanji |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250124657
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| Publikation (Nr.) |
 EGU/EGU2016-4128.pdf |
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| Zusammenfassung |
| Mixed-phase clouds (MPCs) are found to be the most relevant cloud type leading to
precipitation in mid-latitudes. The formation of ice crystals in MPCs is not completely
understood. To estimate the effect of aerosol particles on the radiative properties of clouds
and to describe ice nucleation in models, the specific properties of aerosol particles acting as
ice nucleating particles (INPs) still need to be identified. A number of devices are able to
measure INPs in the lab and in the field. However, methods can be very different and need to
be tested under controlled conditions with respect to aerosol generation and properties in
order to standardize measurement and data analysis approaches for subsequent ambient
measurements.
Here, we present an overview of the LINC campaign hosted at TROPOS in September
2015. We compare four ice nucleation devices: PINC (Portable Ice Nucleation Chamber,
Chou et al., 2011) and SPIN (SPectrometer for Ice Nuclei) are operated in deposition
nucleation and condensation freezing mode. LACIS (Leipzig Aerosol Cloud Interaction
Simulator, Hartmann et al., 2011) and PIMCA (Portable Immersion Mode Cooling chamber)
measure in the immersion freezing mode. PIMCA is used as a vertical extension to PINC and
allows activation and droplet growth prior to exposure to the investigated ice nucleation
temperature. Size-resolved measurements of multiple aerosol types were performed including
pure mineral dust (K-feldspar, kaolinite) and biological particles (Birch pollen washing
waters) as well as some of them after treatment with sulfuric or nitric acid prior to
experiments.
LACIS and PIMCA-PINC operated in the immersion freezing mode showed very good
agreement in the measured frozen fraction (FF). For the comparison between PINC and
SPIN, which were scanning relative humidity from below to above water vapor
saturation, an agreement was found for the obtained INP concentration. However,
some differences were observed, which may result from ice detection and data
treatment. A difference was observed between FF from LACIS and PIMCA-PINC
compared to the ice activated fractions (AF) from PINC and SPIN. This requires further
investigations.
Acknowledgements
Part of this work was funded by the DFG Research Unit FOR 1525 INUIT, grant WE
4722/1-2.
References
Chou et al. (2011), Atmos. Chem. Phys., 11, 4725-4738.
Hartmann et al. (2011), Atmos. Chem. Phys., 11, 1753-1767. |
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