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@ARTICLE{Niedermeier:20009,
author = {Niedermeier, D. and Hartmann, S. and Clauss, T. and Wex, H.
and Kiselev, A. and Sullivan, R.C. and DeMott, P.J. and
Petters, M.D. and Reitz, P. and Schneider, J. and Mikhailov,
E. and Sierau, B. and Stetzer, O. and Reimann, B. and
Bundke, U. and Shaw, R.A. and Buchholz, A. and Mentel, T.F.
and Stratmann, F.},
title = {{E}xperimental study of the role of physicochemical surface
processing on the {IN} ability of mineral dust particles},
journal = {Atmospheric chemistry and physics},
volume = {11},
issn = {1680-7316},
address = {Katlenburg-Lindau},
publisher = {EGU},
reportid = {PreJuSER-20009},
pages = {11131 - 11144},
year = {2011},
note = {This work is part of a DFG project under contract HE
939/21-1 and the Russian Foundation for Basic Research
(grant 10-03-00950-a). The measurement campaign FROST 2 was
conducted within the Helmholtz Virtual Institute
"Aerosol-Cloud Interactions" funded by the Helmholtz
society. R. C. Sullivan and P. J. DeMott acknowledge
additional support for US National Science Foundation grant
ATM-0841602. Additionally, the campaign was financially
supported by the research project EUROCHAMP funded within
the EC 6th Framework Program, Section "Support for Research
Infrastructures - Integrated Infrastructure Initiative". We
would also like to thank J. Curtius, University of
Frankfurt, for a valuable discussion, and the
Interdisciplinary Resource Center for Nanotechnology of St.
Petersburg State University and E. Ubyivovk for TEM analysis
of the ATD samples.},
abstract = {During the measurement campaign FROST 2 (FReezing Of duST
2), the Leipzig Aerosol Cloud Interaction Simulator (LACIS)
was used to investigate the influence of various surface
modifications on the ice nucleating ability of Arizona Test
Dust (ATD) particles in the immersion freezing mode. The
dust particles were exposed to sulfuric acid vapor, to water
vapor with and without the addition of ammonia gas, and heat
using a thermodenuder operating at 250 degrees C. Size
selected, quasi monodisperse particles with a mobility
diameter of 300 nm were fed into LACIS and droplets grew on
these particles such that each droplet contained a single
particle. Temperature dependent frozen fractions of these
droplets were determined in a temperature range between -40
degrees C <= T <= -28 degrees C. The pure ATD particles
nucleated ice over a broad temperature range with their
freezing behavior being separated into two freezing branches
characterized through different slopes in the frozen
fraction vs. temperature curves. Coating the ATD particles
with sulfuric acid resulted in the particles' IN potential
significantly decreasing in the first freezing branch (T >
-35 degrees C) and a slight increase in the second branch (T
<= -35 degrees C). The addition of water vapor after the
sulfuric acid coating caused the disappearance of the first
freezing branch and a strong reduction of the IN ability in
the second freezing branch. The presence of ammonia gas
during water vapor exposure had a negligible effect on the
particles' IN ability compared to the effect of water vapor.
Heating in the thermodenuder led to a decreased IN ability
of the sulfuric acid coated particles for both branches but
the additional heat did not or only slightly change the IN
ability of the pure ATD and the water vapor exposed sulfuric
acid coated particles. In other words, the combination of
both sulfuric acid and water vapor being present is a main
cause for the ice active surface features of the ATD
particles being destroyed. A possible explanation could be
the chemical transformation of ice active metal silicates to
metal sulfates. The strongly enhanced reaction between
sulfuric acid and dust in the presence of water vapor and
the resulting significant reductions in IN potential are of
importance for atmospheric ice cloud formation. Our findings
suggest that the IN concentration can decrease by up to one
order of magnitude for the conditions investigated.},
keywords = {J (WoSType)},
cin = {IEK-8},
ddc = {550},
cid = {I:(DE-Juel1)IEK-8-20101013},
pnm = {Atmosphäre und Klima},
pid = {G:(DE-Juel1)FUEK491},
shelfmark = {Meteorology $\&$ Atmospheric Sciences},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000296967900022},
doi = {10.5194/acp-11-11131-2011},
url = {https://juser.fz-juelich.de/record/20009},
}