A5005515350- Atmospheric aerosols and clouds
- Atmospheric chemistry and aerosols
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Meteorological Phenomena and Simulations
- Solar Radiation and Photovoltaics
- Advanced Aircraft Design and Technologies
- Air Quality and Health Impacts
- Geochemistry and Geologic Mapping
- Air Traffic Management and Optimization
- Remote-Sensing Image Classification
- Calibration and Measurement Techniques
- Aeolian processes and effects
- Geophysics and Gravity Measurements
- Ionosphere and magnetosphere dynamics
- Climate variability and models
- Air Quality Monitoring and Forecasting
- Earthquake Detection and Analysis
- Remote Sensing in Agriculture
- Cryospheric studies and observations
- Solar and Space Plasma Dynamics
- Vehicle emissions and performance
- Aviation Industry Analysis and Trends
- COVID-19 impact on air quality
- Numerical methods in inverse problems
Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)
2011-2024
Czech Academy of Sciences, Institute of Atmospheric Physics
2012-2014
Fraunhofer Institute for Solar Energy Systems
2010
ETH Zurich
1996-1997
Abstract. libRadtran is a widely used software package for radiative transfer calculations. It allows one to compute (polarized) radiances, irradiance, and actinic fluxes in the solar thermal spectral regions. has been various applications, including remote sensing of clouds, aerosols trace gases Earth's atmosphere, climate studies, e.g., calculation forcing due different atmospheric components, UV forecasting, photolysis frequencies, other planets our system. The described Mayer Kylling...
Abstract The Midlatitude Cirrus experiment (ML-CIRRUS) deployed the High Altitude and Long Range Research Aircraft (HALO) to obtain new insights into nucleation, life cycle, climate impact of natural cirrus aircraft-induced contrail cirrus. Direct observations properties their variability are still incomplete, currently limiting our understanding clouds’ on climate. Also, dynamical effects clouds feedbacks not adequately represented in today’s weather prediction models. Here, we present...
Abstract During spring 2020, the COVID-19 pandemic caused massive reductions in emissions from industry and ground airborne transportation. To explore resulting atmospheric composition changes, we conducted BLUESKY campaign with two research aircraft measured trace gases, aerosols, cloud properties boundary layer to lower stratosphere. From 16 May 9 June performed 20 flights early lockdown phase over Europe Atlantic Ocean. We found up 50% nitrogen dioxide concentrations urban areas GOME-2B...
Abstract. The strong reduction of air traffic during the COVID-19 pandemic provides a unique test case for relationship between density, contrails, and their radiative forcing climate change. Here, contrail cirrus changes are quantified European domain March to August 2020 compared same period in 2019. Traffic data show 72 % flight distance with This paper investigates induced model study. results depend on various methodological details as discussed parameter studies. In reference case,...
The COVID-19 pandemic led to a 72% reduction of air traffic over Europe in March-August 2020 compared 2019. Modeled contrail cover declined similarly, and computed mean instantaneous radiative forcing dropped regionally by up 0.7 W m-2. Here, model predictions cirrus optical thickness the top-of-atmosphere outgoing longwave reflected shortwave irradiances are tested comparison Meteosat-SEVIRI-derived data. agreement between observations modeled data is slightly better when contributions...
Abstract. Knowledge of humidity in the upper troposphere and lower stratosphere (UTLS) is special interest due to its importance for cirrus cloud formation climate impact. However, UTLS water vapor distribution current weather models subject large uncertainties. Here, we develop a dynamic-based correction method using an artificial neural network (ANN) improve relative over ice (RHi) ECMWF numerical predictions. The model trained with time-dependent thermodynamic dynamical variables from...
Abstract. A novel approach for the detection of cirrus clouds and retrieval optical thickness top altitude based on measurements Spinning Enhanced Visible Infrared Imager (SEVIRI) aboard geostationary Meteosat Second Generation (MSG) satellite is presented. Trained with 8 000 co-incident Cloud-Aerosol Lidar Orthogonal Polarization (CALIOP) Pathfinder Satellite Observations (CALIPSO) mission new "cirrus properties derived from CALIOP SEVIRI algorithm during day night" (COCS) utilizes a...
Abstract. Cirrus clouds play an important role in climate as they tend to warm the Earth–atmosphere system. Nevertheless their physical properties remain one of largest sources uncertainty atmospheric research. To better understand processes cirrus and impact, enhanced satellite observations are necessary. In this paper we present a new algorithm, CiPS (Cirrus Properties from SEVIRI), that detects retrieves corresponding cloud top height, ice optical thickness water path using SEVIRI imager...
Abstract. Validation of cloud properties retrieved from passive spaceborne imagers is essential for and climate applications but complicated due to the large differences in scale observation geometry between satellite footprint independent ground based or airborne observations. Here we illustrate demonstrate an alternative approach: starting output COSMO-EU weather model German Weather Service realistic three-dimensional structures at a spatial 2.33 km are produced by statistical downscaling...
Volcanic ash clouds can damage aircrafts during flight and, thus, have the potential to disrupt air traffic on a large scale, making their detection and monitoring necessary. The new retrieval algorithm VACOS (Volcanic Ash Cloud properties Obtained from SEVIRI) using geostationary instrument MSG/SEVIRI artificial neural networks is introduced in companion paper. It performs pixelwise classifications retrieves (indirectly) mass column concentration, cloud top height effective particle radius....
Abstract. Contrail cirrus constitute the largest radiative forcing (RF) component to total aviation effect on climate. However, microphysical properties and effects of contrail natural clouds in same meteorological conditions are still not completely resolved. Motivated by these uncertainties, we investigate an extended region perturbed North Atlantic (NAR) 26 March 2014 during Midlatitude Cirrus (ML-CIRRUS) experiment. On that day, high air traffic density NAR combined with large scale cold...
This paper describes the first-ever operational contrail avoidance trial in real world, which took place region of Maastricht Upper Area Control (including northwest Germany, Benelux countries and part North Sea) year 2021.Contrail could be an efficient method for mitigating climate impact aviation.Applying a deliberate experiment design, air traffic was deviated every other day by changing flight altitude up to 2000 ft or down if potential persistent contrails were predicted.Whether...
Abstract. The role of clouds remains the largest uncertainty in climate projections. They influence solar and thermal radiative transfer earth's water cycle. Therefore, there is an urgent need for accurate cloud observations to validate models monitor change. Passive satellite imagers measuring radiation at visible infrared (IR) wavelengths provide a wealth information on properties. Among others, top height (CTH) – crucial parameter estimate forcing can be retrieved. In this paper we...
Abstract. During the CIRCLE-2 experiment carried out over Western Europe in May 2007, combined situ and remote sensing observations allowed to describe microphysical optical properties near-top of an overshooting convective cloud (11 080 m/−58 °C). The airborne measurements were performed with DLR Falcon aircraft specially equipped a unique set instruments for extensive (Polar Nephelometer, FSSP-300, Cloud Particle Imager PMS 2-D-C) nadir looking (DLR WALES Lidar). Quasi-simultaneous space...
The spaceborne detection of volcanic ash clouds at infrared wavelengths helps to avoid regions with enhanced concentrations that pose a threat aviation. Current data retrievals require detailed information on microphysical properties and the refractive index ash, which are highly variable. Uncertainties in latter currently limit quality nowcasts. Here, we introduce novel method calculate complex indices ashes from 5 15 μm measurements their individual components based generic petrological...
Abstract. The purpose of the EUNADICS-AV (European Natural Airborne Disaster Information and Coordination System for Aviation) prototype early warning system (EWS) is to develop combined use harmonised data products from satellite, ground-based in situ instruments produce alerts airborne hazards (volcanic, dust, smoke radionuclide clouds), satisfying requirement aviation air traffic management (ATM) stakeholders (https://cordis.europa.eu/project/id/723986, last access: 5 November 2021)....
Besides the goal of net-zero carbon dioxide (CO2) emissions, reduction aviation's climate impact requires mitigation its other forcing effects, most importantly avoidance warming condensation trails (contrails). From current understanding a decrease both, soot and water vapor emissions from aircraft engines yields reduced occurrence persistence contrails contrail cirrus, reducing their radiative forcing. The WaterEnhanced Turbofan (WET) for instance is one concept that achieves both effects...
Contrail cirrus represents the most significant warming component within total aviation impact on climate, suspected to exceed even effects of CO2 emissions. It remains be shown that regulating hydrogen and sulfur content in kerosene could help reduce climate from contrails, order allow for a science-based jet fuel standardization. Hence, this study conducts model-based scenario analysis European fleet 2019, exploring different levels aromatic reductions fossil fuel-based as short-term...
Contrail cirrus is estimated to be the largest contributor global effective radiative forcing from aviation, surpassing even aviation CO2 emissions in their impact. One promising mitigation strategy contrail avoidance by rerouting flights avoid regions where warming contrails can persist. These are forecast with numerical models fed weather prediction model output. Satellite imagery presents a good opportunity evaluate both and success of strategy.An automatic detection algorithm was...
Abstract. libRadtran is a widely used software package for radiative transfer calculations. It allows to compute (polarized) radiances, irradiances, and actinic fluxes in the solar thermal spectral regions. has been various applications, including remote sensing of clouds, aerosols trace gases Earth's atmosphere, climate studies, e.g., calculation forcing due different atmospheric components, UV-forcasting, photolysis frequencies, other planets our system. The described Mayer Kylling...
Abstract. High-quality volcanic ash forecasts are crucial to minimize the economic impact of hazards on air traffic. Decision-making is usually based numerical dispersion modelling with only one model realization. Given inherent uncertainty such an approach, a multi-model multi-source term ensemble has been designed and evaluated for Eyjafjallajökull eruption in May 2010. Its use flight planning discussed. Two ensembles were built: first output four models their own implementation ejection....
Abstract. Knowledge of humidity in the upper troposphere and lower stratosphere (UTLS) is special interest due to its importance for cirrus cloud formation climate impact. However, UTLS water vapor distribution current weather models subject large uncertainties. Here, we develop a dynamic-based correction method using artificial neural network (ANN) improve relative over ice (RHi) ECMWF numerical predictions. The model trained with time-dependent thermodynamic dynamical variables from ERA5...
Abstract. Modifications of existing clouds by the exhaust ships are well-known but inadequately quantified impacts, which could contribute to climate change. The perturbation a cloud layer ship-generated aerosol changes reflectivity and is identified long curves in satellite images, known as ship tracks. As tracks indicate pollution very clean marine environment also affect radiation budget below above cloud, it important investigate their radiative climatic effects. Satellite-data from...
Abstract. Cirrus clouds remain one of the key uncertainties in atmospheric research. To better understand properties and physical processes cirrus clouds, accurate large-scale observations from satellites are required. Artificial neural networks (ANNs) have proved to be a useful tool for cloud remote sensing. Since physics is not modelled explicitly ANNs, thorough characterisation necessary. In this paper CiPS (Cirrus Properties SEVIRI) algorithm characterised using space-borne lidar CALIOP....