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| Titel |
Ice Nucleation Activity of Various Agricultural Soil Dust Aerosol Particles |
| VerfasserIn |
Thea Schiebel, Kristina Höhler, Roger Funk, Thomas C. J. Hill, Ezra J. T. Levin, Jens Nadolny, Isabelle Steinke, Kaitlyn J. Suski, Romy Ullrich, Robert Wagner, Ines Weber, Paul J. DeMott, Ottmar Möhler |
| 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 |
250132875
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| Publikation (Nr.) |
 EGU/EGU2016-13422.pdf |
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| Zusammenfassung |
| Recent investigations at the cloud simulation chamber AIDA (Aerosol Interactions and
Dynamics in the Atmosphere) suggest that agricultural soil dust has an ice nucleation ability
that is enhanced up to a factor of 10 compared to desert dust, especially at temperatures above
-26 ∘C (Steinke et al., in preparation for submission). This enhancement might be caused by
the contribution of very ice-active biological particles. In addition, soil dust aerosol
particles often contain a considerably higher amount of organic matter compared
to desert dust particles. To test agricultural soil dust as a source of ice nucleating
particles, especially for ice formation in warm clouds, we conducted a series of
laboratory measurements with different soil dust samples to extend the existing AIDA
dataset.
The AIDA has a volume of 84 m3 and operates under atmospherically relevant conditions
over wide ranges of temperature, pressure and humidity. By controlled adiabatic expansions,
the ascent of an air parcel in the troposphere can be simulated. As a supplement to
the AIDA facility, we use the INKA (Ice Nucleation Instrument of the KArlsruhe
Institute of Technology) continuous flow diffusion chamber based on the design by
Rogers (1988) to expose the sampled aerosol particles to a continuously increasing
saturation ratio by keeping the aerosol temperature constant. For our experiments,
soil dust was dry dispersed into the AIDA vessel. First, fast saturation ratio scans
at different temperatures were performed with INKA, sampling soil dust aerosol
particles directly from the AIDA vessel. Then, we conducted the AIDA expansion
experiment starting at a preset temperature. The combination of these two different
methods provides a robust data set on the temperature-dependent ice activity of various
agriculture soil dust aerosol particles with a special focus on relatively high temperatures.
In addition, to extend the data set, we investigated the role of biological and organic
matter in more detail to gain additional information on the trigger of the enhanced ice
nucleation activity of soil dust.
References
Rogers (1988): Development of a continuous flow thermal gradient diffusion chamber for
ice nucleation studies
Steinke et al. (In preparation for submission): Ice nucleation activity of agricultural soil
dust aerosols from Mongolia, Argentina and Germany |
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