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Title: Ice nucleation properties of mineral dust particles: Determination of onset RHi, IN active fraction, nucleation time-lag, and the effect of active sites on contact angles

Abstract

A newly developed ice nucleation experimental set up was used to investigate the heterogeneous ice nucleation properties of three Saharan and one Spanish dust particle samples. It is observed that the spread in the onset relative humidities with respect to ice (RHi) for Saharan dust particles varies from 104% to 110%, whereas for the Spanish dust from 106% to 110%. The elemental composition analysis shows a prominent Ca feature in the Spanish dust sample which could potentially explain the differences in nucleation threshold. Although spread in the onset RHi for Saharan dust samples were in agreement, their active fractions and nucleation time-lags calculated at various temperature and RHi conditions, for two Saharan dust samples, were not found to be in complete agreement. This could be because of the subtle variation in the elemental composition of the dust samples, and the surface irregularities like steps, cracks, cavities etc. A combination of classical nucleation theory and active site theory is used to understand the importance of these surface irregularities, expressed in terms of active sites, on the nucleability parameter (contact angle) that is widely used in the ice cloud modeling studies. These calculations show that the surface irregularities reduce the contact anglemore » by approximately 10 degrees.« less

Authors:
;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
983420
Report Number(s):
PNNL-SA-65434
TRN: US201014%%322
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Atmospheric Chemistry and Physics, 10(1):95-105
Additional Journal Information:
Journal Volume: 10; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; CAVITIES; CLOUDS; DUSTS; NUCLEATION; SIMULATION; Ice nucleation; aerosols; ice chamber

Citation Formats

Kulkarni, Gourihar R, and Dobbie, Steven. Ice nucleation properties of mineral dust particles: Determination of onset RHi, IN active fraction, nucleation time-lag, and the effect of active sites on contact angles. United States: N. p., 2010. Web. doi:10.5194/acp-10-95-2010.
Kulkarni, Gourihar R, & Dobbie, Steven. Ice nucleation properties of mineral dust particles: Determination of onset RHi, IN active fraction, nucleation time-lag, and the effect of active sites on contact angles. United States. https://doi.org/10.5194/acp-10-95-2010
Kulkarni, Gourihar R, and Dobbie, Steven. 2010. "Ice nucleation properties of mineral dust particles: Determination of onset RHi, IN active fraction, nucleation time-lag, and the effect of active sites on contact angles". United States. https://doi.org/10.5194/acp-10-95-2010.
@article{osti_983420,
title = {Ice nucleation properties of mineral dust particles: Determination of onset RHi, IN active fraction, nucleation time-lag, and the effect of active sites on contact angles},
author = {Kulkarni, Gourihar R and Dobbie, Steven},
abstractNote = {A newly developed ice nucleation experimental set up was used to investigate the heterogeneous ice nucleation properties of three Saharan and one Spanish dust particle samples. It is observed that the spread in the onset relative humidities with respect to ice (RHi) for Saharan dust particles varies from 104% to 110%, whereas for the Spanish dust from 106% to 110%. The elemental composition analysis shows a prominent Ca feature in the Spanish dust sample which could potentially explain the differences in nucleation threshold. Although spread in the onset RHi for Saharan dust samples were in agreement, their active fractions and nucleation time-lags calculated at various temperature and RHi conditions, for two Saharan dust samples, were not found to be in complete agreement. This could be because of the subtle variation in the elemental composition of the dust samples, and the surface irregularities like steps, cracks, cavities etc. A combination of classical nucleation theory and active site theory is used to understand the importance of these surface irregularities, expressed in terms of active sites, on the nucleability parameter (contact angle) that is widely used in the ice cloud modeling studies. These calculations show that the surface irregularities reduce the contact angle by approximately 10 degrees.},
doi = {10.5194/acp-10-95-2010},
url = {https://www.osti.gov/biblio/983420}, journal = {Atmospheric Chemistry and Physics, 10(1):95-105},
number = 1,
volume = 10,
place = {United States},
year = {Fri Jan 08 00:00:00 EST 2010},
month = {Fri Jan 08 00:00:00 EST 2010}
}