The origins of ice crystals measured in mixed-phase clouds at the high-alpine site Jungfraujoch
During the winter of 2013 and 2014 measurements of cloud microphysical properties over a 5-week period at the high-alpine site Jungfraujoch, Switzerland, were carried out as part of the Cloud Aerosol Characterisation Experiments (CLACE) and the Ice Nucleation Process Investigation and Quantification...
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ftdoajarticles:oai:doaj.org/article:522969780cf644db8bcfebd6123cedf2 2023-05-15T16:55:38+02:00 The origins of ice crystals measured in mixed-phase clouds at the high-alpine site Jungfraujoch G. Lloyd T. W. Choularton K. N. Bower M. W. Gallagher P. J. Connolly M. Flynn R. Farrington J. Crosier O. Schlenczek J. Fugal J. Henneberger 2015-11-01T00:00:00Z https://doi.org/10.5194/acp-15-12953-2015 https://doaj.org/article/522969780cf644db8bcfebd6123cedf2 EN eng Copernicus Publications http://www.atmos-chem-phys.net/15/12953/2015/acp-15-12953-2015.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 1680-7316 1680-7324 doi:10.5194/acp-15-12953-2015 https://doaj.org/article/522969780cf644db8bcfebd6123cedf2 Atmospheric Chemistry and Physics, Vol 15, Iss 22, Pp 12953-12969 (2015) Physics QC1-999 Chemistry QD1-999 article 2015 ftdoajarticles https://doi.org/10.5194/acp-15-12953-2015 2022-12-31T01:57:55Z During the winter of 2013 and 2014 measurements of cloud microphysical properties over a 5-week period at the high-alpine site Jungfraujoch, Switzerland, were carried out as part of the Cloud Aerosol Characterisation Experiments (CLACE) and the Ice Nucleation Process Investigation and Quantification project (INUPIAQ). Measurements of aerosol properties at a second, lower site, Schilthorn, Switzerland, were used as input for a primary ice nucleation scheme to predict ice nuclei concentrations at Jungfraujoch. Frequent, rapid transitions in the ice and liquid properties of the clouds at Jungfraujoch were identified that led to large fluctuations in ice mass fractions over temporal scales of seconds to hours. During the measurement period we observed high concentrations of ice particles that exceeded 1000 L −1 at temperatures around −15 °C, verified by multiple instruments. These concentrations could not be explained using the usual primary ice nucleation schemes, which predicted ice nucleus concentrations several orders of magnitude smaller than the peak ice crystal number concentrations. Secondary ice production through the Hallett–Mossop process as a possible explanation was ruled out, as the cloud was rarely within the active temperature range for this process. It is shown that other mechanisms of secondary ice particle production cannot explain the highest ice particle concentrations. We describe four possible mechanisms that could lead to high cloud ice concentrations generated from the snow-covered surfaces surrounding the measurement site. Of these we show that hoar frost crystals generated at the cloud enveloped snow surface could be the most important source of cloud ice concentrations. Blowing snow was also observed to make significant contributions at higher wind speeds when ice crystal concentrations were < 100 L −1 . Article in Journal/Newspaper Inupiaq Directory of Open Access Journals: DOAJ Articles Hallett ENVELOPE(170.217,170.217,-72.317,-72.317) Atmospheric Chemistry and Physics 15 22 12953 12969 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Physics QC1-999 Chemistry QD1-999 |
spellingShingle |
Physics QC1-999 Chemistry QD1-999 G. Lloyd T. W. Choularton K. N. Bower M. W. Gallagher P. J. Connolly M. Flynn R. Farrington J. Crosier O. Schlenczek J. Fugal J. Henneberger The origins of ice crystals measured in mixed-phase clouds at the high-alpine site Jungfraujoch |
topic_facet |
Physics QC1-999 Chemistry QD1-999 |
description |
During the winter of 2013 and 2014 measurements of cloud microphysical properties over a 5-week period at the high-alpine site Jungfraujoch, Switzerland, were carried out as part of the Cloud Aerosol Characterisation Experiments (CLACE) and the Ice Nucleation Process Investigation and Quantification project (INUPIAQ). Measurements of aerosol properties at a second, lower site, Schilthorn, Switzerland, were used as input for a primary ice nucleation scheme to predict ice nuclei concentrations at Jungfraujoch. Frequent, rapid transitions in the ice and liquid properties of the clouds at Jungfraujoch were identified that led to large fluctuations in ice mass fractions over temporal scales of seconds to hours. During the measurement period we observed high concentrations of ice particles that exceeded 1000 L −1 at temperatures around −15 °C, verified by multiple instruments. These concentrations could not be explained using the usual primary ice nucleation schemes, which predicted ice nucleus concentrations several orders of magnitude smaller than the peak ice crystal number concentrations. Secondary ice production through the Hallett–Mossop process as a possible explanation was ruled out, as the cloud was rarely within the active temperature range for this process. It is shown that other mechanisms of secondary ice particle production cannot explain the highest ice particle concentrations. We describe four possible mechanisms that could lead to high cloud ice concentrations generated from the snow-covered surfaces surrounding the measurement site. Of these we show that hoar frost crystals generated at the cloud enveloped snow surface could be the most important source of cloud ice concentrations. Blowing snow was also observed to make significant contributions at higher wind speeds when ice crystal concentrations were < 100 L −1 . |
format |
Article in Journal/Newspaper |
author |
G. Lloyd T. W. Choularton K. N. Bower M. W. Gallagher P. J. Connolly M. Flynn R. Farrington J. Crosier O. Schlenczek J. Fugal J. Henneberger |
author_facet |
G. Lloyd T. W. Choularton K. N. Bower M. W. Gallagher P. J. Connolly M. Flynn R. Farrington J. Crosier O. Schlenczek J. Fugal J. Henneberger |
author_sort |
G. Lloyd |
title |
The origins of ice crystals measured in mixed-phase clouds at the high-alpine site Jungfraujoch |
title_short |
The origins of ice crystals measured in mixed-phase clouds at the high-alpine site Jungfraujoch |
title_full |
The origins of ice crystals measured in mixed-phase clouds at the high-alpine site Jungfraujoch |
title_fullStr |
The origins of ice crystals measured in mixed-phase clouds at the high-alpine site Jungfraujoch |
title_full_unstemmed |
The origins of ice crystals measured in mixed-phase clouds at the high-alpine site Jungfraujoch |
title_sort |
origins of ice crystals measured in mixed-phase clouds at the high-alpine site jungfraujoch |
publisher |
Copernicus Publications |
publishDate |
2015 |
url |
https://doi.org/10.5194/acp-15-12953-2015 https://doaj.org/article/522969780cf644db8bcfebd6123cedf2 |
long_lat |
ENVELOPE(170.217,170.217,-72.317,-72.317) |
geographic |
Hallett |
geographic_facet |
Hallett |
genre |
Inupiaq |
genre_facet |
Inupiaq |
op_source |
Atmospheric Chemistry and Physics, Vol 15, Iss 22, Pp 12953-12969 (2015) |
op_relation |
http://www.atmos-chem-phys.net/15/12953/2015/acp-15-12953-2015.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 1680-7316 1680-7324 doi:10.5194/acp-15-12953-2015 https://doaj.org/article/522969780cf644db8bcfebd6123cedf2 |
op_doi |
https://doi.org/10.5194/acp-15-12953-2015 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
15 |
container_issue |
22 |
container_start_page |
12953 |
op_container_end_page |
12969 |
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1766046617270484992 |