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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ftpubman:oai:pure.mpg.de:item_3489646 2023-08-27T04:10:17+02:00 The origins of ice crystals measured in mixed-phase clouds at the high-alpine site Jungfraujoch Lloyd, G. Choularton, T. Bower, K. Gallagher, M. Connolly, P. Flynn, M. Farrington, R. Crosier, J. Schlenczek, O. Fugal, J. Henneberger, J. 2015-11-24 http://hdl.handle.net/21.11116/0000-000C-8909-0 eng eng info:eu-repo/semantics/altIdentifier/doi/10.5194/acp-15-12953-2015 http://hdl.handle.net/21.11116/0000-000C-8909-0 Atmospheric Chemistry and Physics info:eu-repo/semantics/article 2015 ftpubman https://doi.org/10.5194/acp-15-12953-2015 2023-08-02T01:49:19Z 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 Max Planck Society: MPG.PuRe Hallett ENVELOPE(170.217,170.217,-72.317,-72.317) Atmospheric Chemistry and Physics 15 22 12953 12969 |
institution |
Open Polar |
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Max Planck Society: MPG.PuRe |
op_collection_id |
ftpubman |
language |
English |
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 |
Lloyd, G. Choularton, T. Bower, K. Gallagher, M. Connolly, P. Flynn, M. Farrington, R. Crosier, J. Schlenczek, O. Fugal, J. Henneberger, J. |
spellingShingle |
Lloyd, G. Choularton, T. Bower, K. Gallagher, M. Connolly, P. Flynn, M. Farrington, R. Crosier, J. Schlenczek, O. Fugal, J. Henneberger, J. The origins of ice crystals measured in mixed-phase clouds at the high-alpine site Jungfraujoch |
author_facet |
Lloyd, G. Choularton, T. Bower, K. Gallagher, M. Connolly, P. Flynn, M. Farrington, R. Crosier, J. Schlenczek, O. Fugal, J. Henneberger, J. |
author_sort |
Lloyd, G. |
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 |
publishDate |
2015 |
url |
http://hdl.handle.net/21.11116/0000-000C-8909-0 |
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 |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/acp-15-12953-2015 http://hdl.handle.net/21.11116/0000-000C-8909-0 |
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 |
_version_ |
1775352204770672640 |