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dc.contributor.author
Frick, Claudia
dc.contributor.author
Seifert, Axel
dc.contributor.author
Wernli, Heini
dc.date.accessioned
2019-05-16T10:21:31Z
dc.date.available
2017-06-11T01:59:44Z
dc.date.available
2019-05-16T10:21:31Z
dc.date.issued
2013
dc.identifier.issn
1991-9603
dc.identifier.issn
1991-959X
dc.identifier.other
10.5194/gmd-6-1925-2013
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/76820
dc.identifier.doi
10.3929/ethz-b-000076820
dc.description.abstract
A new snow melting parametrization is presented for the non-hydrostatic limited-area COSMO ("consortium for small-scale modelling") model. In contrast to the standard cloud microphysics of the COSMO model, which instantaneously transfers the meltwater from the snow to the rain category, the new scheme explicitly considers the liquid water fraction of the melting snowflakes. These semi-melted hydrometeors have characteristics (e.g., shape and fall speed) that differ from those of dry snow and rain droplets. Where possible, theoretical considerations and results from vertical wind tunnel laboratory experiments of melting snowflakes are used as the basis for characterising the melting snow as a function of its liquid water fraction. These characteristics include the capacitance, the ventilation coefficient, and the terminal fall speed. For the bulk parametrization, a critical diameter is introduced. It is assumed that particles smaller than this diameter, which increases during the melting process, have completely melted, i.e., they are converted to the rain category. The values of the bulk integrals are calculated with a finite difference method and approximately represented by polynomial functions, which allows an efficient implementation of the parametrization. Two case studies of (wet) snowfall in Germany are presented to illustrate the potential of the new snow melting parametrization. It is shown that the new scheme (i) produces wet snow instead of rain in some regions with surface temperatures slightly above the freezing point, (ii) simulates realistic atmospheric melting layers with a gradual transition from dry snow to melting snow to rain, and (iii) leads to a slower snow melting process. In the future, it will be important to thoroughly validate the scheme, also with radar data and to further explore its potential for improved surface precipitation forecasts for various meteorological conditions.
en_US
dc.format
application/pdf
en_US
dc.language.iso
en
en_US
dc.publisher
Copernicus Publications
en_US
dc.rights.uri
http://creativecommons.org/licenses/by/3.0/
dc.title
A bulk parametrization of melting snowflakes with explicit liquid water fraction for the COSMO model
en_US
dc.type
Journal Article
dc.rights.license
Creative Commons Attribution 3.0 Unported
dc.date.published
2013-11-06
ethz.journal.title
Geoscientific Model Development
ethz.journal.volume
6
en_US
ethz.journal.abbreviated
Geosci. model dev.
ethz.pages.start
1925
en_US
ethz.pages.end
1939
en_US
ethz.version.deposit
publishedVersion
en_US
ethz.identifier.wos
ethz.publication.place
Göttingen
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02350 - Dep. Umweltsystemwissenschaften / Dep. of Environmental Systems Science::02717 - Institut für Atmosphäre und Klima / Inst. Atmospheric and Climate Science::03854 - Wernli, Johann Heinrich / Wernli, Johann Heinrich
en_US
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02350 - Dep. Umweltsystemwissenschaften / Dep. of Environmental Systems Science::02717 - Institut für Atmosphäre und Klima / Inst. Atmospheric and Climate Science::03854 - Wernli, Johann Heinrich / Wernli, Johann Heinrich
ethz.date.deposited
2017-06-11T02:02:37Z
ethz.source
ECIT
ethz.identifier.importid
imp5936515deaf8872192
ethz.ecitpid
pub:121233
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2017-07-19T09:30:17Z
ethz.rosetta.lastUpdated
2019-05-16T10:21:43Z
ethz.rosetta.exportRequired
true
ethz.rosetta.versionExported
true
ethz.COinS
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