Investigating microphysical properties of MPCs and precipitation in mountainous terrain
dc.contributor.author
Schär, Mario
dc.contributor.supervisor
Wieder, Jörg
dc.contributor.supervisor
Lauber, Annika
dc.contributor.supervisor
Henneberger, Jan
dc.date.accessioned
2022-09-26T06:05:25Z
dc.date.available
2022-08-26T07:03:44Z
dc.date.available
2022-08-26T13:30:52Z
dc.date.available
2022-09-26T06:05:25Z
dc.date.issued
2019-09-02
dc.identifier.uri
http://hdl.handle.net/20.500.11850/566640
dc.identifier.doi
10.3929/ethz-b-000566640
dc.description.abstract
While a majority of precipitating clouds in the Alps are mixed-phase clouds (MPCs), a lot of microphysical processes behind ice formation and precipitation initiation are still not fully understood. In this thesis, orographic precipitation events were analysed with measurement data from the RACLETS field campaign in Davos during winter 2019 in order to investigate microphysical properties of precipitation and MPCs. Precipitation was analysed with Parsivel laser disdrometers, while in-situ cloud measurements were taken with the holographic imager HOLIMO. Remote sensing and meteorological observations furthermore provided information about atmospheric conditions during the measurement period. In a first case study, a cold front precipitation event was analysed. Comparing measurements from two Parsivel disdrometers at different locations, observed differences in accumulated precipitation could be explained with microphysical properties of precipitation. Increased snowfall rates at one measurement site were mostly the result of higher precipitation particle number concentrations and higher particle fall velocity in combination. In MPC measurements mostly ice crystals were found, compared to only small cloud droplet number concentrations. Both, ice crystal and cloud droplet number densities increased over time. High cloud particle number concentrations furthermore were also consistent with high radar reflectivities measured with a cloud radar. During a second precipitation event, a transition from rainfall to snowfall was investigated. Using Parsivel disdrometer measurements, a transition from typical raindrop size-velocity distributions to typical snow particle distributions was observed. Furthermore, co-existing raindrops and snow particles were found during the short transition period, resulting in bimodal particle size-velocity distributions. Additionally, a melting layer could be observed with radar in the lowest few hundred metres above ground, consistent with Parsivel measurements on a mountain above the melting layer, where only snowfall was detected.
en_US
dc.format
application/pdf
en_US
dc.language.iso
en
en_US
dc.publisher
ETH Zurich
en_US
dc.rights.uri
http://rightsstatements.org/page/InC-NC/1.0/
dc.subject
Alps; orographic clouds; mixed-phase clouds; snowfall; precipitation; field measurements
en_US
dc.title
Investigating microphysical properties of MPCs and precipitation in mountainous terrain
en_US
dc.type
Master Thesis
dc.rights.license
In Copyright - Non-Commercial Use Permitted
ethz.size
47 p.
en_US
ethz.code.ddc
DDC - DDC::5 - Science::550 - Earth sciences
en_US
ethz.publication.place
Zurich
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::03690 - Lohmann, Ulrike / Lohmann, Ulrike
en_US
ethz.date.deposited
2022-08-26T07:03:50Z
ethz.source
FORM
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2022-09-26T06:05:26Z
ethz.rosetta.lastUpdated
2022-09-26T06:05:26Z
ethz.rosetta.versionExported
true
ethz.COinS
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Master Thesis [2147]