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Exploiting orographic clouds for constraining the sources of ice crystals

English title Exploiting orographic clouds for constraining the sources of ice crystals
Applicant Lohmann Ulrike
Number 175824
Funding scheme Project funding (Div. I-III)
Research institution Institut für Atmosphäre und Klima ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Meteorology
Start/End 01.10.2017 - 30.09.2021
Approved amount 1'300'000.00
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All Disciplines (2)

Discipline
Meteorology
Climatology. Atmospherical Chemistry, Aeronomy

Keywords (5)

in-situ measurements; sources of ice crystals; orographic clouds; precipitation; regional climate modelling

Lay Summary (German)

Lead
Die Alpen sind das Wasserschloss Europas und damit eine bedeutende Wasserquelle. In ihnen entspringen einige der längsten Flüsse Mitteleuropas. In diesem Projekt nutzen wir die Wolken, die sich in den Alpen bilden, sogenannte orographische Wolken, als natürliches Labor. Wir möchten die Prozesse, die in den Wolken dazu führen, dass sich Niederschlag bildet, besser verstehen. Orographische Wolken, die den Berg einhüllen, können auf Bergstationen oder mit Messgeräten bestückten Gondeln vermessen werden. Beides haben wir in Vergangenheit schon gemacht und erste Ergebnisse bekommen. Trotz unserer und vielen anderen Messungen, sind die Quellen von Eiskristallen in Wolken noch immer unverstanden. So werden wiederholt um Grössenordnungen höhere Eiskristallkonzentrationen gemessen als Aerosolpartikel, die als Eiskeime dienen, zur Verfügung stehen.
Lay summary

Inhalt und Ziel des Forschungsprojekts:

In diesem Projekt wollen wir deshalb eine weitere Messplattform, eine Mischung aus einem Fesselballon und einem Drachen, in Betrieb nehmen. Dieser Fesselballon-Drachen erlaubt es uns, Vertikalprofile in Wolkentropfen und Eiskristallen bis zu 1000 m über Grund zu bekommen, was uns Aufschlüsse darüber geben kann, ob Eiskristalle allenfalls von darüber liegenden Wolken in die zu beobachteten Wolken gelangen oder wie häufig Schnee vom Boden her aufgewirbelt wird. Die Wolkenmessungen machen wir mit unserer holographischen Kamera, womit wir auch Aussagen über die räumliche Verteilung von Wolkentropfen und Eiskristallen erhalten, welche wiederum für die Niederschlagsbildung wichtig ist. In ausgesuchten Messkampagnen wollen wir unsere Wolkenmessungen mit Niederschlagsmessungen an verschiedenen Bodenstationen, Radarmessungen der MeteoSchweiz und mit Messungen von Aerosolpartikeln, die als Eiskeime dienen, kombinieren.

Wissenschaftlicher und gesellschaftlicher Kontext des Forschungsprojekts:

Die Feldmessungen in diesem Projekt werden neue Erkenntnisse über die Prozesse in orographischen Wolken generieren. Diese Ergebnisse werden insbesondere unser Verständnis der Niederschlagsentstehung erhöhen, nicht nur in den Alpen, sondern auch für Wolken weltweit.  Die Ergebnisse werden eine Verbesserung von regionalen Wettermodellen ermöglichen um Niederschläge präzisier vorher zu sagen, was insbesondere bei Extremereignissen den Schutz der Bevölkerung vor Überschwemmung erhöht.

Direct link to Lay Summary Last update: 02.10.2017

Responsible applicant and co-applicants

Employees

Publications

Publication
A convolutional neural network for classifying cloud particles recorded by imaging probes
Touloupas Georgios, Lauber Annika, Henneberger Jan, Beck Alexander, Lucchi Aurélien (2020), A convolutional neural network for classifying cloud particles recorded by imaging probes, in Atmospheric Measurement Techniques, 13(5), 2219-2239.
Using a holographic imager on a tethered balloon system for microphysical observations of boundary layer clouds
Ramelli Fabiola, Beck Alexander, Henneberger Jan, Lohmann Ulrike (2020), Using a holographic imager on a tethered balloon system for microphysical observations of boundary layer clouds, in Atmospheric Measurement Techniques, 13(2), 925-939.

Datasets

Aerosol Data Davos Wolfgang

Author Wieder, Jörg; Rösch, Carolin
Publication date 26.05.2020
Persistent Identifier (PID) doi: 10.16904/envidat.157
Repository Envidat
Abstract
Aerosol properties were measured between February 8 and March 31 2019 at the measurement site Davos Wolfgang (LON: 9.853594, LAT: 46.835577). Optical and aerodynamic particle counters, as well as a scanning mobility particle size spectrometer and an ice nuclei counter were deployed to report particle concentrations and size distributions in fine (10-1000 nm) and coarse mode (> 1000 nm), cloud condensation nuclei concentrations (CCNCs) and ice nuclei particle concentrations (ICNCs). The ambient particles were transported via a heated inlet to be distributed to the particle detecting devices inside the setup room.Optical Particle Counter (OPC): Light scattering of a diode laser beam caused by travelling particles is used in the both, the OPC-N3 (0.41 - 38.5 μm) and GT-526S (0.3 - 5 μm), to determine their size and number concentration. For the OPC-N3, particle size spectra and concentration data are used afterwards to calculate PM₁, PM₂,₅ and PM₁₀ (assumptions: particle density: 1.65 g cm³, refractive index: 1.5+i0).Aerodynamic Particle Sizer (APS): The APS (3321, TSI Inc.) measured the particle size distribution for aerodynamic diameters between 0.5 μm and ~20 μm by the particle’s time-of-flight and light-scattering intensity (assumptions: particle density 1 g cm³).Scanning Mobility Particle Size Spectrometer (SMPS): Particle number concentrations in a size range between 12 and 460 nm (electrical mobility diameter) were measured at Davos Wolfgang, using a Scanning Mobility Particle Sizer Spectrometer (3938, TSI Inc.). The classifier (3082, TSI Inc.) was equipped with a neutralizer (3088, TSI Inc.) and a differential mobility analyzer working with negative polarity (3081, TSI Inc.). The size selected particles were counted by a water-based condensation particle counter (3788 , TSI Inc.). The TSI AIM software was used to provide particle size distributions by applying multiple charge and diffusion loss corrections (assumptions: particle density 1 g cm³).Coriolis μ and DRINCZ: A microbial air sampler (Coriolis μ, bertin Instruments) was used to collect airborne particles for investigating their ice nucleating ability with a droplet freezing device. Particles larger than 0.5 μm were drawn with an air flow rate of up to 300 l min¹ into the cone and centrifuged into the wall of the cone due to the forming vortex. The liquid sample was transferred into the DRoplet Ice Nuclei Counter Zurich (DRINCZ, ETH Zurich) to study heterogeneous ice formation (immersion freezing mode) of ambient airborne particles.

Aerosol Data Weissfluhjoch

Author Wieder, Jörg; Rösch, Carolin
Publication date 26.05.2020
Persistent Identifier (PID) doi: 10.16904/envidat.156
Repository Envidat
Abstract
Aerosol properties were measured between February 8 and March 31 2019 at the measurement site Weissfluhjoch (LON: 9.806475, LAT: 46.832964). Optical and aerodynamic particle counters, as well as a scanning mobility particle size spectrometer and an ice nuclei counter were deployed to report particle concentrations and size distributions in fine (10-1000 nm) and coarse mode (> 1000 nm), cloud condensation nuclei concentrations (CCNCs), and ice nuclei particle concentrations (ICNCs). The ambient particles were transported via a heated inlet to be distributed to the particle detecting devices inside the setup room.Optical Particle Counter (OPC): Light scattering of a diode laser beam caused by travelling particles is used in the both, the OPC-N3 (0.41 - 38.5 μm) and GT-526S (0.3 - 5 μm), to determine their size and number concentration. For the OPC-N3, particle size spectra and concentration data are used afterwards to calculate PM₁, PM₂,₅ and PM₁₀ (assumptions: particle density: 1.65 g cm³, refractive index: 1.5+i0).Aerodynamic Particle Sizer (APS): The APS (3321, TSI Inc.) measured the particle size distribution for aerodynamic diameters between 0.5 μm and ~20 μm by the particle’s time-of-flight and light-scattering intensity (assumptions: particle density 1 g cm³).Scanning Mobility Particle Size Spectrometer (SMPS): Particle number concentrations in a size range between 12 and 460 nm (electrical mobility diameter) were measured at Davos Wolfgang, using a Scanning Mobility Particle Sizer Spectrometer (SMPS 3938, TSI Inc.). The classifier (3082, TSI Inc.) was equipped with a neutralizer (3088, TSI Inc.) and a differential mobility analyzer working with negative polarity (3081, TSI Inc.). The size selected particles were counted by a water-based condensation particle counter (3787 TSI Inc.). The TSI AIM software was used to provide particle size distributions by applying multiple charge and diffusion loss corrections (assumptions: particle density 1 g cm³).Coriolis μ and LINDA: A microbial air sampler (Coriolis μ, bertin Instruments) was used to collect airborne particles for investigating their ice nucleating ability with a droplet freezing device. Particles larger than 0.5 μm were drawn with an air flow rate of up to 300 l min‾¹ into the cone and centrifuged into the wall of the cone due to the forming vortex. The liquid sample was transferred into the LED based Ice Nucleation Detection Apparatus (LINDA, University of Basel) to study heterogeneous ice formation (immersion freezing mode) of ambient airborne particles.

Disdrometer Data Davos Wolfgang

Author Seifert, Patric; Wieder, Jörg
Publication date 09.10.2019
Persistent Identifier (PID) 10.16904/envidat.117
Repository Envidat
Abstract
The dataset contains information on precipitation amount and type for Davos Wolfgang (LON: 9.853594, LAT: 46.835577) from February 8 to March 19 2019. It includes: characteristics of hydrometeors (e.g. diameter, fall velocity, amount per diameter class,...), precipitation rate, radar reflectivity, visibility range, weather codes and instrument performance.

Weather Station Davos Wolfgang

Author Wieder, Jörg
Publication date 04.02.2020
Persistent Identifier (PID) doi: 10.16904/envidat.137
Repository Envidat
Abstract
The dataset contains weather parameters measured at Davos Wolfgang (LON: 9.853594, LAT: 46.835577).

Collaboration

Group / person Country
Types of collaboration
Dr. Patric Seifert, TROPOS Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Prof. Susanne Crewell, University of Cologne Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure
Prof Trude Storelvmo, University of Oslo Norway (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel
Dr. Roland Neuber, AWI Germany (Europe)
- Research Infrastructure
Dr. Franz Conen, University of Basel Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Prof. Alexis Berne, LTE, EPFL Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure
Dr. Alexander Häfele, MeteoSwiss Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Prof. Michael Lehning, CRYOS, EPFL + WSL/SLF Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Prof. Paul Zieger, Stockholm university Sweden (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Prof. Athanasios Nenes, LAPI, EPFL Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Virtual Alpine Observatory Symposium Talk given at a conference RACLETS campaign:The quest for the origin of ice crystal in Alpine clouds 04.02.2020 Berm, Switzerland Lauber Annika; Beck Alexander; Wieder Jörg; Lohmann Ulrike; Ramelli Fabiola; Rösch Carolin; Dedekind Zane;
AGU Fall Meeting 2019 Talk given at a conference Evidence of secondary ice production in orographic mixed-phase clouds: An observational and modelling study 09.12.2019 San Francisco, United States of America Lauber Annika; Lohmann Ulrike; Ramelli Fabiola; Wieder Jörg;
35th International Conference on Alpine Meteorology Talk given at a conference High resolution measurements of orographic mixed-phase clouds 03.09.2019 Riva del Garda, Italy Ramelli Fabiola; Beck Alexander; Lohmann Ulrike;
International Conference on Alpine Meteorology Poster RACLETS field campaign – A multidimensional approach to study precipitation formation in orographic clouds. 02.09.2019 Riva del Garda, Italy Lohmann Ulrike; Lauber Annika; Ramelli Fabiola; Wieder Jörg;
Arctic Science Summit Week 2019 Talk given at a conference Comparison of Microphysical Processes in Alpine and Arctic Mixed-Phase Clouds 24.05.2019 Arkhangelsk, Russia Wieder Jörg; Lauber Annika; Lohmann Ulrike;
EGU Poster verview of a measurement campaign to explore alpine clouds to understand precipitation formation and snow deposition. 03.05.2019 Vienna, Austria Dedekind Zane; Wieder Jörg; Lauber Annika; Lohmann Ulrike; Ramelli Fabiola; Beck Alexander;
EGU Meeting 2019 Poster Investigating secondary ice processes in the regional COSMO model 07.04.2019 Wien, Austria Lauber Annika; Lohmann Ulrike; Dedekind Zane;
AMS annual meeting Talk given at a conference Orographic mixed-phase clouds 09.01.2019 Phoenix, Arizona, United States of America Lohmann Ulrike; Ramelli Fabiola; Beck Alexander;
AMS Cloud Physics Conference Talk given at a conference Observing the Microstructure of Boundary Layer Clouds using a Holographic Imager on a Tethered Balloon. Oral presentation 09.07.2018 Vancouver, Canada Beck Alexander; Ramelli Fabiola; Lohmann Ulrike;
AMS Poster Can a Deep Learning Algorithm improve the Automated Classification of Cloud Imager Particle Data? 09.07.2018 Vancouver, Canada Lauber Annika;
UK Atmospheric Science Conference Talk given at a conference Aerosol-Cloud Interactions in Mixed-Phase Clouds and their Role for Climate 04.07.2018 York, Great Britain and Northern Ireland Lohmann Ulrike; Lauber Annika; Ramelli Fabiola; Beck Alexander;
Polar2018 Talk given at a conference Sources of ice crystals and cloud droplets in orographic mixed-phase clouds 20.06.2018 Davos, Switzerland Ramelli Fabiola; Lohmann Ulrike; Beck Alexander; Lauber Annika;
BACCHUS final meeting Poster Observations of the Small-Scale Cloud Structure using a Holographic Imager on a Tethered Balloon and Cable Car. Poster presentation 24.04.2018 Zürich, Switzerland Lohmann Ulrike; Beck Alexander; Ramelli Fabiola;
14th International Conference on the Physics and Chemistry of Ice Poster Ice particle classification using a deep learning algorithm 08.01.2018 Zürich, Switzerland Lauber Annika;


Self-organised

Title Date Place
Ny-Alesund campaign meeting 29.06.2020 Online, Switzerland
RACLETS Data meeting 03.02.2020 Zürich, Switzerland
RACLETS Data meeting 04.07.2019 Zürich, Switzerland
Kick-off meeting Davos campaign 26.11.2018 Zürich, Switzerland
HoloSuite Workshop 22.10.2018 Zürich, Switzerland

Knowledge transfer events

Active participation

Title Type of contribution Date Place Persons involved
MeteoSchweiz Forecaster-Kurs Talk 12.11.2019 Zürich, Switzerland Rösch Carolin; Wieder Jörg; Lauber Annika; Ramelli Fabiola; Beck Alexander; Dedekind Zane; Lohmann Ulrike;
Jungfraujoch awards the EPS Historic Site 2019 Talk 07.02.2019 Bern, Switzerland Beck Alexander; Ramelli Fabiola; Lohmann Ulrike;
General assembly Sonnblick-Verein Talk 07.06.2018 Salzburg, Austria Lauber Annika;


Communication with the public

Communication Title Media Place Year
Media relations: print media, online media Campagne de mesures avec ballon captif à Davos (GR) La Liberte Western Switzerland 2019
Media relations: print media, online media Die Wissenschaft geht in die Luft Südöstschweiz German-speaking Switzerland 2019
Media relations: print media, online media Ein Fesselballon für die Wolkenforschung Der Bote Western Switzerland 2019
Media relations: print media, online media Fesselballon solll kontinuierlichen Blick ins Innere von Wolken generieren Der Standard International 2019
Media relations: print media, online media GEHEIMNISVOLLE WOLKEN: WIE ENTSTEHEN SCHNEEKRISTALLE? MDR International 2019
Media relations: print media, online media Meteorolgie: Fesselballon soll Prozesse im Inneren von Wolken vermessen Blick German-speaking Switzerland 2019
Media relations: radio, television Morgengast SRF 1 German-speaking Switzerland 2019
Media relations: radio, television Taagesschau SRF 1 German-speaking Switzerland 2019
Media relations: print media, online media Über Davos, da steht ein Wetterballon Südostschweiz Western Switzerland 2019

Awards

Title Year
Doctorate of Philosophy honoris causa from Stockholm University 2018

Associated projects

Number Title Start Funding scheme
154450 Paleo fires from high-alpine ice cores 01.01.2015 Sinergia
160177 A new parameterization scheme for ice and snow in climate models 01.04.2015 Project funding (Div. I-III)
156581 Elucidating Ice Nucleation Mechanisms Relevant to the Atmosphere: Is deposition nucleation really immersion freezing in pores? 01.02.2015 Project funding (Div. I-III)
166726 Climate Engineering by Arctic Winter Cirrus Thinning: Risks andFeasibility (AWiCiT) 01.05.2016 Project funding (Div. I-III)
152813 Measurements of water uptake by fresh and aged wood-burning soot particles in the subsaturated regime 01.12.2014 Project funding (Div. I-III)

Abstract

Orographic clouds provide a natural laboratory that can be exploited to understand the physical processes leading to precipitation. In this proposal, we focus on ice-containing clouds, which are key to understanding and predicting precipitation in mid-latitudes. The Alps are the "water towers of Europe" with the origin of the largest rivers in Central Europe and thus an important freshwater source in Europe. We will target orographic clouds in the Alps, for which understanding precipitation formation is crucial and which are most readily accessible. The sources of ice crystals in these clouds still remain an enigma. Irreconcilable large discrepancies exist between measured ice crystal concentrations and those expected from primary ice nucleation on ice-active aerosol (observed and simulated) and known ice multiplication processes. We propose a multi-faceted approach in the Alps to obtain all sources of ice crystals: from ice-active aerosol, secondary ice formation, ice falling from clouds above, and surface ice sources. This requires a novel approach utilising an airborne platform on a tethered balloon system (TBS) equipped with a holographic imager to obtain measurements of vertical profiles and the three-dimensional (3D) spatial distribution of cloud particles. Holography is the only method capable of these conducting these measurements. In dedicated campaigns, we propose to combine in-situ measurements of cloud microphysical properties within the cloud with precipitation measurements at various sites at the surface and measurements of cloud condensation nuclei and ice nucleating particles at a mountain-top site to simultaneously determine the ice crystal sources in- and out of the cloud. We will compare our precipitation measurements from several disdrometers with the widespread precipitation data from the MeteoSwiss dual polarization precipitation radar in Davos.To put the conducted measurements in a larger context, we will use the regional numerical weather prediction model COSMO to simulate our field campaigns, test the importance of the different ice crystal sources for orographic precipitation and the role anthropogenic aerosols play for these. We will improve the parameterisation of cloud microphysical processes in COSMO. By doing so, we will provide an estimate of the importance of ice crystals and snowflakes falling from a higher-lying cloud into a lower-lying one (seeder-feeder process), which has been speculated to promote extreme precipitation events. This will help with early warnings for extreme precipitation and preventive measures against flash floods, landslides and avalanches.
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