A5002129025- Atmospheric aerosols and clouds
- Meteorological Phenomena and Simulations
- Precipitation Measurement and Analysis
- Atmospheric chemistry and aerosols
- Climate variability and models
- Atmospheric Ozone and Climate
- Aeolian processes and effects
- Plant Water Relations and Carbon Dynamics
- Human-Automation Interaction and Safety
- Cryospheric studies and observations
- Icing and De-icing Technologies
- Atmospheric and Environmental Gas Dynamics
- Earthquake Detection and Analysis
- Aerospace and Aviation Technology
- Fire effects on ecosystems
- Nuclear Physics and Applications
- Ionosphere and magnetosphere dynamics
- Cyclone Separators and Fluid Dynamics
- Arctic and Antarctic ice dynamics
- Geophysics and Gravity Measurements
- Air Traffic Management and Optimization
- Parallel Computing and Optimization Techniques
- Safety Warnings and Signage
- Climate change and permafrost
- Solar Radiation and Photovoltaics
Leipzig University
2019-2024
University of Bayreuth
2020-2021
Leibniz Institute for Tropospheric Research
2018-2021
Rockwell Automation (United States)
1999-2002
Abstract Clouds play an important role in Arctic amplification. This term represents the recently observed enhanced warming of relative to global increase near-surface air temperature. However, there are still knowledge gaps regarding interplay between clouds and aerosol particles, surface properties, as well turbulent radiative fluxes that inhibit accurate model simulations climate system. In attempt resolve this so-called cloud puzzle, two comprehensive closely coordinated field studies...
Abstract. In a warming Arctic the increased occurrence of new particle formation (NPF) is believed to originate from declining ice coverage during summertime. Understanding physico-chemical properties newly formed particles, as well mechanisms that control both and growth in this pristine environment, important for interpreting aerosol–cloud interactions, which climate can be highly sensitive. investigation, we present analysis NPF high summer Arctic. The measurements were made on-board...
Abstract. Ice-nucleating particles (INPs) initiate the primary ice formation in clouds at temperatures above ca. −38 ∘C and have an impact on precipitation formation, cloud optical properties, persistence. Despite their roles both weather climate, INPs are not well characterized, especially remote regions such as Arctic. We present results from a ship-based campaign to European Arctic during May July 2017. deployed filter sampler continuous-flow diffusion chamber for offline online INP...
Abstract. Cloud and precipitation processes are still a main source of uncertainties in numerical weather prediction climate change projections. The Priority Programme “Polarimetric Radar Observations meet Atmospheric Modelling (PROM)”, funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG), is guided hypothesis that many relate to lack observations suitable challenge representation cloud atmospheric models. Such can, however, at present be provided recently...
Abstract. Polarimetric radars provide variables like the specific differential phase (KDP) to detect fingerprints of dendritic growth in layer (DGL) and secondary ice production, both critical for precipitation formation. A key challenge interpreting radar observations is lack situ validation particle properties within measurement volume. While high KDP snow usually associated with number concentrations, only few studies attributed certain hydrometeor types sizes. To address this, we...
Abstract. Advancing the understanding of mixed-phase cloud microphysical growth processes requires a thorough detection transition from pristine hydrometeor states toward aggregates, rimed particles and graupel. In this study, versatile combination techniques is applied to detect characterize aggregated strongly hydrometeors even under adverse atmospheric conditions, such as presence orographic gravity waves. This approach combines dual-frequency observations vertical-stare Doppler radars...
Abstract. In many types of clouds, multiple hydrometeor populations can be present at the same time and height. Studying evolution these different hydrometeors in a time–height perspective give valuable information on cloud particle composition microphysical growth processes. However, as prerequisite, number certain volume needs to quantified. This accomplished using radar Doppler velocity spectra from profiling radars if have sufficiently terminal fall velocities produce individual spectrum...
Abstract. Riming, i.e., the accretion and freezing of supercooled liquid water (SLW) on ice particles in mixed-phase clouds, is an important pathway for precipitation formation. Detecting quantifying riming using ground-based cloud radar observations great interest; however, approaches based measurements mean Doppler velocity (MDV) are unfeasible convective orographically influenced systems. Here, we show how artificial neural networks (ANNs) can be used to predict ground-based,...
Abstract. In mixed-phase clouds, the variable mass ratio between liquid water and ice as well spatial distribution within cloud plays an important role in lifetime, precipitation processes, radiation budget. Data sets of vertically pointing Doppler radars lidars provide insights into properties at high temporal resolution. Cloud are able to penetrate multiple layers can potentially be used expand identification phase entire vertical column beyond lidar signal attenuation height, by...
In the Arctic, new particle formation (NPF) and subsequent growth processes are keys to produce Aitken-mode particles, which under certain conditions can act as cloud condensation nuclei (CCNs). The activation of particles increases CCN budget Arctic low-level clouds and, accordingly, affects climate forcing. However, mechanism from NPF into range in summertime boundary layer remains a subject current research. this combined cruise field modeling study, we investigated sizes above 80 nm. A...
Abstract. Cloud radar Doppler spectra are of particular interest for investigating cloud microphysical processes, such as ice formation, riming and multiplication. When hydrometeor types within a observation volume have sufficiently different terminal fall velocities, they produce individual spectrum peaks, convoluted by dynamical effects. If these (sub-)peaks can be separated, properties the underlying populations potentially estimated, their velocity, number, size to some extent shape....
Abstract. In mixed-phase clouds, the variable mass ratio between liquid water and ice as well spatial distribution within cloud plays an important role for life time, precipitation processes, radiation budget. Data sets of vertically-pointing Doppler radars lidars provide insights into properties at high temporal resolution. Cloud are able to penetrate multiple layers can potentially be used expand identification phase entire vertical column beyond lidar signal attenuation height, by...
Abstract. Continuous long-term ground-based remote-sensing observations combined with vertically pointing cloud radar and ceilometer measurements are well suited for identifying precipitation evaporation fall streaks (so-called virga). Here we introduce the functionality workflow of a new open-source tool, Virga-Sniffer, which was developed within framework RV Meteor during ElUcidating RolE Cloud–Circulation Coupling in ClimAte (EUREC4A) field experiment January–February 2020 tropical...
While Synthetic Vision Information Systems (SVIS) are still in the research and development stages, it is possible that we will see them become an integral part of commercial flight deck. The goal this study was to evaluate SVIS display against a conventional glass cockpit display. conducted fixed base laboratory simulator located Operator Performance Laboratory (OPL) at University Iowa. Twelve pilot evaluators hand-flew fairly difficult approaches into Eagle County Colorado (KEGE) airport....
Data from the Flight Safety Foundation (FSF) shows that hull-loss accident rate for commercial jet transports during last two decades has essentially remained constant at around 1.5 accidents per million departures. If air traffic volume doubles as expected in next decade, absolute number of will increase, even if current low remains low. Public perception flight safety is generally based on and not rates. Therefore reduction such actual decreases must be a primary goal; otherwise predicted...
Abstract. Accurately measuring the turbulent transport of reactive and conservative greenhouse gases, heat, organic compounds between surface atmosphere is critical for understanding trace gas exchange its response to changes in climate anthropogenic activities. The relaxed eddy accumulation (REA) method enables land when fast-response sensors are not available, broadening suite gases that can be investigated. β factor scales concentration differences flux, choice central successfully using...
Abstract. In a warming Arctic the increased occurrence of new particle formation (NPF) is believed to originate from declining ice coverage during summertime. Understanding physico-chemical properties newly formed particles, as well mechanisms that control both and growth in this pristine environment important for interpreting aerosol-cloud interactions, which climate can be highly sensitive. investigation, we present analysis NPF high summer Arctic. The measurements have been done on-board...
Abstract Aerial insects are vital for nature and society. Though methods to observe flying have consistently improved in the last decades, remain difficult monitor systematically over large spatial temporal scales. Remote sensing with radars has proved be one of more effective tools observation. However, as most sensitive targets similar size radar wavelength, detectable sub-group aerial a certain range depends on employed radar. Here, we present novel method based data zenith-pointing...
Abstract. Advancing the understanding of mixed-phase cloud microphysical growth processes requires a thorough detection transition from pristine hydrometeor states toward aggregates, rimed particles and graupel. In this study, versatile combination techniques is applied to detect characterize aggregated strongly hydrometeors even under harsh atmospheric conditions such as presence orographic gravity waves. The approach combines dual-frequency observations vertical-stare Doppler radars well...
Abstract. Cloud radar Doppler spectra are of particular interest for investigating cloud microphysical processes, such as ice formation, riming and multiplication. When hydrometeor types within a observation volume have different terminal fall velocities, they can produce individual spectrum peaks. The peaks particle overlap be further broadened blended by turbulence other dynamical effects. If these (sub-)peaks separated, properties the underlying populations potentially estimated, their...
Research approaches using synthetic vision systems (SVS) were flown into the Eagle County Regional Airport (KEGE) in Eagle-Vail, Colorado during period from August 19 to September 9, 2001. The conducted with NASA's Aries 757 research aircraft. NASA, who funded these tests flights, and Rockwell Collins evaluated their respective SVS display concepts separate qualitative quantitative assessment techniques. This paper describes results obtained information system (SVIS) concept. SVIS uses a...
Abstract. Riming, i.e. the accretion and freezing of SLW on ice particles in mixed-phase clouds, is an important pathway for precipitation formation. Detecting quantifying riming using ground-based cloud radar observations great interest, however, approaches based measurements mean Doppler velocity (MDV) are unfeasible convective orographically influenced systems. Here, we show how artificial neural networks (ANNs) can be used to predict zenith-pointing variables as input features. ANNs a...