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| Titel |
A new thermal gradient ice nucleation diffusion chamber instrument: design, development and first results using Saharan mineral dust |
| VerfasserIn |
G. Kulkarni, S. Dobbie, J. B. McQuaid |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 2, no. 1 ; Nr. 2, no. 1 (2009-06-11), S.221-229 |
| Datensatznummer |
250000439
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| Publikation (Nr.) |
 copernicus.org/amt-2-221-2009.pdf |
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| Zusammenfassung |
| A new Thermal Gradient ice nucleation Diffusion Chamber (TGDC) capable of
investigating ice nucleation efficiency of atmospherically important
aerosols, termed Ice Nuclei (IN), has been designed, constructed and
validated. The TGDC can produce a range of supersaturations with respect to
ice (SSi) over the temperature range of −10 to −34°C for
sufficiently long time needed to observe the ice nucleation by the
particles. The novel aspect of this new TGDC is that the chamber is run in
static mode with aerosol particles supported on a Teflon substrate, which
can be raised and lowered in a controlled way through the SSi profile
within the chamber, and nucleation events are directly observed using
digital photography. The TGDC consists of two ice coated plates to which a
thermal gradient is applied to produce the range of SSi. The design of
the TGDC gives the ability to understand time-related ice nucleation event
information and to perform experiments at different temperatures and SSi
conditions for different IN without changing the thermal gradient within
the TGDC. The temperature and SSi conditions of the experimental system
are validated by observing (NH4)2SO4 deliquescence and the
results are in good agreement with the literature data. First results are
presented of the onset ice nucleation for mineral dust sampled from the
Saharan Desert, including images of nucleation and statistical distributions
of onset ice nucleation SSi as a function of temperature. This paper
illustrates how useful this new TGDC is for process level studies of ice
nucleation and more experimental investigations are needed to better
quantify the role of ice formation in the atmosphere. |
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