Ice nucleation efficiency of natural dust samples in the immersion mode
A total of 12 natural surface dust samples, which were surface-collected on four continents, most of them in dust source regions, were investigated with respect to their ice nucleation activity. Dust collection sites were distributed across Africa, South America, the Middle East, and Antarctica. Min...
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ftleibnizopen:oai:oai.leibnizopen.de:MN-Pm4YBdbrxVwz6fXeo 2023-05-15T14:02:47+02:00 Ice nucleation efficiency of natural dust samples in the immersion mode Kaufmann, Lukas Marcolli, Claudia Hofer, Julian Pinti, Valeria Hoyle, Christopher R. Peter, Thomas 2016 application/pdf https://doi.org/10.34657/1028 https://oa.tib.eu/renate/handle/123456789/918 eng eng München : European Geopyhsical Union CC BY 3.0 Unported https://creativecommons.org/licenses/by/3.0/ CC-BY Atmospheric Chemistry and Physics, Volume 16, Issue 17, Page 11177-11206 550 article Text 2016 ftleibnizopen https://doi.org/10.34657/1028 2023-03-01T07:25:03Z A total of 12 natural surface dust samples, which were surface-collected on four continents, most of them in dust source regions, were investigated with respect to their ice nucleation activity. Dust collection sites were distributed across Africa, South America, the Middle East, and Antarctica. Mineralogical composition has been determined by means of X-ray diffraction. All samples proved to be mixtures of minerals, with major contributions from quartz, calcite, clay minerals, K-feldspars, and (Na, Ca)-feldspars. Reference samples of these minerals were investigated with the same methods as the natural dust samples. Furthermore, Arizona test dust (ATD) was re-evaluated as a benchmark. Immersion freezing of emulsion and bulk samples was investigated by differential scanning calorimetry. For emulsion measurements, water droplets with a size distribution peaking at about 2 µm, containing different amounts of dust between 0.5 and 50 wt % were cooled until all droplets were frozen. These measurements characterize the average freezing behaviour of particles, as they are sensitive to the average active sites present in a dust sample. In addition, bulk measurements were conducted with one single 2 mg droplet consisting of a 5 wt % aqueous suspension of the dusts/minerals. These measurements allow the investigation of the best ice-nucleating particles/sites available in a dust sample. All natural dusts, except for the Antarctica and ATD samples, froze in a remarkably narrow temperature range with the heterogeneously frozen fraction reaching 10 % between 244 and 250 K, 25 % between 242 and 246 K, and 50 % between 239 and 244 K. Bulk freezing occurred between 255 and 265 K. In contrast to the natural dusts, the reference minerals revealed ice nucleation temperatures with 2–3 times larger scatter. Calcite, dolomite, dolostone, and muscovite can be considered ice nucleation inactive. For microcline samples, a 50 % heterogeneously frozen fraction occurred above 245 K for all tested suspension concentrations, and a microcline ... Article in Journal/Newspaper Antarc* Antarctica LeibnizOpen (The Leibniz Association) |
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550 Kaufmann, Lukas Marcolli, Claudia Hofer, Julian Pinti, Valeria Hoyle, Christopher R. Peter, Thomas Ice nucleation efficiency of natural dust samples in the immersion mode |
topic_facet |
550 |
description |
A total of 12 natural surface dust samples, which were surface-collected on four continents, most of them in dust source regions, were investigated with respect to their ice nucleation activity. Dust collection sites were distributed across Africa, South America, the Middle East, and Antarctica. Mineralogical composition has been determined by means of X-ray diffraction. All samples proved to be mixtures of minerals, with major contributions from quartz, calcite, clay minerals, K-feldspars, and (Na, Ca)-feldspars. Reference samples of these minerals were investigated with the same methods as the natural dust samples. Furthermore, Arizona test dust (ATD) was re-evaluated as a benchmark. Immersion freezing of emulsion and bulk samples was investigated by differential scanning calorimetry. For emulsion measurements, water droplets with a size distribution peaking at about 2 µm, containing different amounts of dust between 0.5 and 50 wt % were cooled until all droplets were frozen. These measurements characterize the average freezing behaviour of particles, as they are sensitive to the average active sites present in a dust sample. In addition, bulk measurements were conducted with one single 2 mg droplet consisting of a 5 wt % aqueous suspension of the dusts/minerals. These measurements allow the investigation of the best ice-nucleating particles/sites available in a dust sample. All natural dusts, except for the Antarctica and ATD samples, froze in a remarkably narrow temperature range with the heterogeneously frozen fraction reaching 10 % between 244 and 250 K, 25 % between 242 and 246 K, and 50 % between 239 and 244 K. Bulk freezing occurred between 255 and 265 K. In contrast to the natural dusts, the reference minerals revealed ice nucleation temperatures with 2–3 times larger scatter. Calcite, dolomite, dolostone, and muscovite can be considered ice nucleation inactive. For microcline samples, a 50 % heterogeneously frozen fraction occurred above 245 K for all tested suspension concentrations, and a microcline ... |
format |
Article in Journal/Newspaper |
author |
Kaufmann, Lukas Marcolli, Claudia Hofer, Julian Pinti, Valeria Hoyle, Christopher R. Peter, Thomas |
author_facet |
Kaufmann, Lukas Marcolli, Claudia Hofer, Julian Pinti, Valeria Hoyle, Christopher R. Peter, Thomas |
author_sort |
Kaufmann, Lukas |
title |
Ice nucleation efficiency of natural dust samples in the immersion mode |
title_short |
Ice nucleation efficiency of natural dust samples in the immersion mode |
title_full |
Ice nucleation efficiency of natural dust samples in the immersion mode |
title_fullStr |
Ice nucleation efficiency of natural dust samples in the immersion mode |
title_full_unstemmed |
Ice nucleation efficiency of natural dust samples in the immersion mode |
title_sort |
ice nucleation efficiency of natural dust samples in the immersion mode |
publisher |
München : European Geopyhsical Union |
publishDate |
2016 |
url |
https://doi.org/10.34657/1028 https://oa.tib.eu/renate/handle/123456789/918 |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_source |
Atmospheric Chemistry and Physics, Volume 16, Issue 17, Page 11177-11206 |
op_rights |
CC BY 3.0 Unported https://creativecommons.org/licenses/by/3.0/ |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.34657/1028 |
_version_ |
1766273198709538816 |