Pre-activation of ice-nucleating particles by the pore condensation and freezing mechanism
In spite of the resurgence in ice nucleation research a comparatively small number of studies deal with the phenomenon of pre-activation in heterogeneous ice nucleation. Fifty years ago, it was shown that various mineral dust and volcanic ash particles can be pre-activated to become nuclei for i...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2016-02-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/2025/2016/acp-16-2025-2016.pdf |
| _version_ | 1818097001698426880 |
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| author | R. Wagner A. Kiselev O. Möhler H. Saathoff I. Steinke |
| author_facet | R. Wagner A. Kiselev O. Möhler H. Saathoff I. Steinke |
| author_sort | R. Wagner |
| collection | DOAJ |
| description | In spite of the resurgence in ice nucleation research a comparatively small
number of studies deal with the phenomenon of pre-activation in
heterogeneous ice nucleation. Fifty years ago, it was shown that
various mineral dust and volcanic ash particles can be pre-activated to
become nuclei for ice crystal formation even at temperatures as high as 270–271 K. Pre-activation was achieved under ice-subsaturated conditions
without any preceding macroscopic ice growth by just temporarily cooling the
particles to temperatures below 228 K. A two-step mechanism involving
capillary condensation of supercooled water and subsequent homogeneous
freezing was proposed to account for the particles' enhanced ice nucleation
ability at high temperatures. This work reinvestigates the efficiency of the
proposed pre-activation mechanism in temperature-cycling experiments
performed in a large cloud chamber with suspended particles. We find the
efficiency to be highest for the clay mineral illite as well as for highly
porous materials like zeolite and diatomaceous earth, whereas most aerosols
generated from desert dust surface samples did not reveal a measurable
pre-activation ability. The pre-activation efficiency is linked to particle
pores in a certain size range. As estimated by model calculations, only
pores with diameters between about 5 and 8 nm contribute to pre-activation
under ice-subsaturated conditions. This range is set by a combination of
requirements from the negative Kelvin effect for condensation and a critical
size of ice embryos for ice nucleation and melting. In contrast to the early
study, pre-activation is only observed for temperatures below 260 K. Above
that threshold, the particles' improved ice nucleation ability disappears
due to the melting of ice in the pores. |
| first_indexed | 2024-12-10T23:13:35Z |
| format | Article |
| id | doaj.art-219c784ec8fc44bb8c9f959f60880318 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-10T23:13:35Z |
| publishDate | 2016-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-219c784ec8fc44bb8c9f959f608803182022-12-22T01:29:53ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242016-02-01162025204210.5194/acp-16-2025-2016Pre-activation of ice-nucleating particles by the pore condensation and freezing mechanismR. Wagner0A. Kiselev1O. Möhler2H. Saathoff3I. Steinke4Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research (IMK-AAF), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, GermanyKarlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research (IMK-AAF), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, GermanyKarlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research (IMK-AAF), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, GermanyKarlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research (IMK-AAF), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, GermanyKarlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research (IMK-AAF), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, GermanyIn spite of the resurgence in ice nucleation research a comparatively small number of studies deal with the phenomenon of pre-activation in heterogeneous ice nucleation. Fifty years ago, it was shown that various mineral dust and volcanic ash particles can be pre-activated to become nuclei for ice crystal formation even at temperatures as high as 270–271 K. Pre-activation was achieved under ice-subsaturated conditions without any preceding macroscopic ice growth by just temporarily cooling the particles to temperatures below 228 K. A two-step mechanism involving capillary condensation of supercooled water and subsequent homogeneous freezing was proposed to account for the particles' enhanced ice nucleation ability at high temperatures. This work reinvestigates the efficiency of the proposed pre-activation mechanism in temperature-cycling experiments performed in a large cloud chamber with suspended particles. We find the efficiency to be highest for the clay mineral illite as well as for highly porous materials like zeolite and diatomaceous earth, whereas most aerosols generated from desert dust surface samples did not reveal a measurable pre-activation ability. The pre-activation efficiency is linked to particle pores in a certain size range. As estimated by model calculations, only pores with diameters between about 5 and 8 nm contribute to pre-activation under ice-subsaturated conditions. This range is set by a combination of requirements from the negative Kelvin effect for condensation and a critical size of ice embryos for ice nucleation and melting. In contrast to the early study, pre-activation is only observed for temperatures below 260 K. Above that threshold, the particles' improved ice nucleation ability disappears due to the melting of ice in the pores.https://www.atmos-chem-phys.net/16/2025/2016/acp-16-2025-2016.pdf |
| spellingShingle | R. Wagner A. Kiselev O. Möhler H. Saathoff I. Steinke Pre-activation of ice-nucleating particles by the pore condensation and freezing mechanism Atmospheric Chemistry and Physics |
| title | Pre-activation of ice-nucleating particles by the pore condensation and freezing mechanism |
| title_full | Pre-activation of ice-nucleating particles by the pore condensation and freezing mechanism |
| title_fullStr | Pre-activation of ice-nucleating particles by the pore condensation and freezing mechanism |
| title_full_unstemmed | Pre-activation of ice-nucleating particles by the pore condensation and freezing mechanism |
| title_short | Pre-activation of ice-nucleating particles by the pore condensation and freezing mechanism |
| title_sort | pre activation of ice nucleating particles by the pore condensation and freezing mechanism |
| url | https://www.atmos-chem-phys.net/16/2025/2016/acp-16-2025-2016.pdf |
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