@inproceedings{WeberFischerLangeetal.2015, author = {Weber, Konradin and Fischer, Christian and Lange, Martin and Pohl, Tobias and B{\"o}hlke, Christoph and Wagner, Frank and Mattis, Ina and Flentje, Harald and Sturm, Klaus and Barth, Joachim and Steinkopff, Thomas and Vogel, Andreas}, title = {Aircraft measurements compared with ceilometer measurements during a sahara dust period in Germany}, series = {Geophysical Research Abstracts: EGU General Assembly 2015}, volume = {17}, booktitle = {Geophysical Research Abstracts: EGU General Assembly 2015}, publisher = {Copernicus}, address = {G{\"o}ttingen}, year = {2015}, abstract = {A significant Sahara dust event took place at the beginning of April 2014 over large areas of Germany and Europe. The German Weather Service (DWD) detected and monitored the expansion and propagation of this dust cloud with a ceilometer network of more than 50 ceilometers. Moreover, these ceilometers were also able to track the altitude of the dust cloud at the positions of the ceilometers. Additionally, aircraft measurements over Germany and France were performed with two aircraft by the Duesseldorf University of Applied Sciences. These aircraft were equipped with optical particle counters (OPC) and were able to measure the particle size distribution within the Sahara dust cloud and as a result of this to calculate the particle mass concentration of the dust. The ceilometer measurements and the aircraft measurements complemented each other: whereas the ceilometers gave continuous information about the Sahara dust cloud at the ceilometer positions, the aircraft measurements delivered interpolating results between the ceilometer positions. Moreover, at several ceilometer positions intercomparison flights were performed by spiraling with the aircraft up or down around the ceilometer laser beam. This gave the unique possibility for comparing the remote sensing results of the ceilometers with the in-situ measurements of the aircraft. This study shows that a significant high amount of Saharan dust particles was transported over Germany during a several days long episode. Furthermore, the intercomparison study between the German ceilometer network and aircraft measurements results shows a good agreement. A combination of these techniques could help to detect the vertical and horizontal distribution of the dust cloud and additionally the particle mass concentration.}, subject = {Deutscher Wetterdienst}, language = {en} } @inproceedings{ArnasonEliassonWeberetal.2015, author = {Arnason, Gylfi and Eliasson, Jonas and Weber, Konradin and B{\"o}hlke, Christoph and Palsson, Thorgeir and R{\"o}gnvaldsson, {\´O}lafur and Thorsteinsson, Throstur and Platt, Ulrich and Tirpitz, Lukas and Jones, Roderic L. and Smith, Paul D.}, title = {Results of airborne measurements in the plume near and far from the 2014 Bardarbunga-Holuhraun eruption}, series = {Geophysical Research Abstracts: EGU General Assembly 2015}, volume = {17}, booktitle = {Geophysical Research Abstracts: EGU General Assembly 2015}, publisher = {Copernicus}, address = {G{\"o}ttingen}, year = {2015}, abstract = {The Volcanic Ash Research (VAR) group is focused on airborne measurement of ash contamination to support safe air travel. In relations to the recent eruption, the group measured ash and several gaseous species in the plume 10-300 km from the volcano. The eruption emitted ash turned out to be mostly in the fine aerosol range (much less than 10 micrometers in diameter). Our highest measured concentrations were lower than 1 mg/m3 indicating that commercial air traffic was not threatened (greater than 2 mg/m3) by the ash contamination. But we measured sulfur dioxide (SO2 ) up to 90 mg/m3, which presented a potentially dangerous pollution problem. However, airborne measurements indicate that the sulfur concentration decays (probably due to scavenging) as the plume is carried by the wind from the volcano, which limits the area of immediate danger to the public. Here we present size distribution for particulate matter collected during flights, near and far from the crater at various times. The particle data is then compared with simultaneously collected sulfur dioxide data and the rate of decay of is estimated. Sulfur and particle concentration variations with height in the far plume are presented. Some airborne measurements for H2S, NO, NO2 and CO2 will also be presented. This includes correlation matrices for simultaneous measurements of these gases and comparison to National Air Quality Standards and background values.}, subject = {Vulkanasche}, language = {en} } @inproceedings{RoegnvaldssonArnasonPalssonetal.2015, author = {R{\"o}gnvaldsson, {\´O}lafur and Arnason, Gylfi and Palsson, Thorgeir and Eliasson, Jonas and Weber, Konradin and B{\"o}hlke, Christoph and Thorsteinsson, Throstur and Tirpitz, Lukas and Platt, Ulrich and Smith, Paul D. and Jones, Roderic L.}, title = {Modeling of SO2 dispersion from the 2014 Holuhraun eruption in Iceland using WRF-Chem}, series = {Geophysical Research Abstracts: EGU General Assembly 2015}, volume = {17}, booktitle = {Geophysical Research Abstracts: EGU General Assembly 2015}, publisher = {Copernicus}, address = {G{\"o}ttingen}, year = {2015}, abstract = {The fissure eruption in Holuhraun in central Iceland is the country's largest lava and gas eruption since 1783 but has produced very little volcanic ash. The eruption started in late August 2014 and is still ongoing as of January 2015. The main threat from this event has been atmospheric pollution of SO2 that is carried by wind to all parts of the country and produces elevated concentrations of SO2 that have frequently violated National Air Quality Standards (NAQS) in many population centers. The Volcanic Ash Research (VAR) group in Iceland is focused on airborne measurement of ash contamination to support safe air travel, as well as various gas concentrations. In relation to the Holuhraun eruption the VAR group has organized an investigation campaign including 10 measurement flights and performed measurements of both the source emissions and the plume distribution. SO2 concentrations measured at the source showed clear potential for creating pollution events in the toxic range and contamination of surface waters. The data obtained in the measurement campaign was used for calibration of the WRF-chem model of the dispersion of SO2 and volcanic ash concentration. The model has both been run in operational forecast mode (since mid October) as well as in a dynamical downscaling mode, to estimate the dispersion and fallout of SO2 from the plume. The model results indicate that a large part of the sulphur was precipitated in the Icelandic highlands. The first melt waters during the spring thaw are likely to contain acid sulphur compounds that can be harmful for vegetation, with the highland vegetation being the most vulnerable. These results will be helpful to estimate the pollution load on farmlands and pastures of farmers.}, subject = {Vulkanismus}, language = {en} } @inproceedings{WeberFischerAmend2020, author = {Weber, Konradin and Fischer, Christian and Amend, Detlef}, title = {A new development of drop-sondes for the measurement of CO2-concentrations at extended volcanic areas}, series = {Physics of Volcanoes 2020}, booktitle = {Physics of Volcanoes 2020}, pages = {32}, year = {2020}, abstract = {One of the main compounds emitted by volcanoes or volcanic fields is CO2. This is not only emitted from localized craters, but can emerge as distributed and fugitive emissions on extended volcanic areas. In this situation it is of interest to explore the distribution and horizontal concentration profiles of the CO2-emissions. For this purpose new drop-sondes for sensor measurements of CO2 emissions are under development at the Duesseldorf University of Applied Sciences. These drop-sondes are designed to be dropped from aircraft or drones over volcanic areas in order to map the distributed CO2 concentrations over longer times in an unattended way. They are very lightweight and cheap, so that a large number of drop-sondes might be deployed even over remote areas or regions with difficult access. The data are transmitted with GSM broadcasting and can be visualized on a geographical map. The drop-sondes use an NDIR CO2 sensor as a base for the measurement unit. Additionally to CO2 the atmospheric pressure, temperature and humidity are measured. The sensor unit is mounted in a special shock absorbing housing, which is designed to absorb impacts from the touch down after dropping of the sensor and is able to resist even adverse weather conditions. First measurement results and more details of the design of the sensor unit will be presented in this contribution}, subject = {Sonde}, language = {en} } @inproceedings{WeberKramerFischeretal.2019, author = {Weber, Konradin and Kramer, Tim and Fischer, Christian and Pohl, Tobias and B{\"o}hlke, Christoph}, title = {Application and Feld-Testing of Different Low Cost Sensors for Particulate Matter}, series = {European Aerosol Conference 2019, 25.-30. August 2019, Gothenburg, Sweden}, booktitle = {European Aerosol Conference 2019, 25.-30. August 2019, Gothenburg, Sweden}, year = {2019}, subject = {Messtechnik}, language = {en} } @inproceedings{WeberReichardtFischeretal.2012, author = {Weber, Konradin and Reichardt, R. and Fischer, Christian and Moser, H. M. and Eliasson, Jonas}, title = {Computational Visualization of Volcanic Ash Plume Concentrations Measured by light Aircrafts over Germany and Iceland during the Recent Eruptions of the Volcanoes Eyjafjallaj{\"o}kull and Grimsv{\"o}tn}, series = {Recent advances in Fluid Mechanics, Heat \& Mass Transfer, Biology and Ecology}, booktitle = {Recent advances in Fluid Mechanics, Heat \& Mass Transfer, Biology and Ecology}, editor = {Jha, Manoj K. and Lazard, Myriam and Zaharim, Azami and Sopian, Kamaruzzaman}, publisher = {WSEAS}, isbn = {978-1-61804-065-7}, pages = {236 -- 240}, year = {2012}, subject = {Vulkanasche}, language = {en} } @inproceedings{VogelWeberFischeretal.2011, author = {Vogel, Andreas and Weber, Konradin and Fischer, Christian and van Haren, G{\"u}nther and Pohl, Tobias and Grobety, Bernhard and Meier, Mario}, title = {Airborne in-situ measurements of the Eyjafjalloj{\"o}kull ash plume with a small aircraft and optical particle spectrometers over north-western Germany - comparison between the aircraft measurements and the VAAC-model calculations}, series = {Geophysical Research Abstracts: EGU General Assembly 2011}, volume = {13}, booktitle = {Geophysical Research Abstracts: EGU General Assembly 2011}, publisher = {Copernicus}, address = {G{\"o}ttingen}, year = {2011}, abstract = {The eruption of the volcano Eyjafjallaj{\"o}kull (Iceland) in 2010 has caused a transportation of an ash dust plume over large areas of Europe. In April 2010 many airports in Europe were closed for several days because of the volcano ash plume and even in May 2010 several German and European airports were closed for shorter periods because of the danger caused by the volcanic ash dust. The VAAC (Volcanic Ash Advisory Center), London, has continuously published graphics of the predicted spread and dispersion of the volcanic ash plume, which were partly basis for the air traffic restrictions in Germany. In this situation the Laboratory for Environmental Measurement Techniques of the University of Applied Sciences in Duesseldorf has performed 14 measurement flights starting from April 23 2010 to May 21 2010 to get real airborne in-situ dust measurement data over the north-western part of Germany and for comparison with the predicted ash dispersion model data of the VAAC of London in Germany. Moreover, airborne passive DOAS remote sensing measurements have been performed by a mini-DOAS system for SO2-measurements within the plume. In this paper the results of the airborne optical ash particle measurements as well as the remote sensing SO2 measurements will be reported for situations with and without the volcanic plume over northern Germany in detail. Moreover, the measured dust data will be compared with the model dispersion predictions for the ash plume by the VAAC and with European limit concentrations. Main conclusions are: The „ash plume", found by the aircraft measurement of the Duesseldorf University of Applied Sciences over north western Germany in the "red zone" predicted by the VAAC turned out to be inhomogeneous during the measurement flights Clusters of ash plume sometimes had only a height extension of several hundred meters or less Ash substructures with a horizontal extension of ten kilometres up to several tenth of kilometres could be found Vertical double structures of ash plume could be measured by spiral flights and could be observed visually in horizontal direction Ash plume could be observed visually as small brown layer in horizontal direction Particles collected during flight could be identified as ash particles by electron microscope analysis and chemical analysis}, subject = {Vulkanasche}, language = {en} } @article{PohlHewelingFischeretal.2017, author = {Pohl, T. and Heweling, G. and Fischer, C. and Weber, Konradin}, title = {Traffic Influenced Nitrogen Dioxide, Ultrafine Particle and Black Carbon Concentrations at a Busy Urban Street in Duesseldorf, Germany}, series = {International Journal of Environmental Science}, volume = {2}, journal = {International Journal of Environmental Science}, issn = {2367-8941}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-50355}, pages = {410 -- 417}, year = {2017}, abstract = {In this study the road traffic related air pollution within a busy urban street canyon in the City of Duesseldorf, Germany was investigated. For the investigations the measurement truck of the laboratory for environmental measurement techniques of the HSD was equipped with different measurement devices for gaseous and aerosol species as well as meteorological sensors. The measurement truck was placed next to a stationary air quality measurement container of the Environmental State Agency of North-Rhine-Westphalia (LANUV). The measurement site is located at the Cornelius street, a direct north south connecting street through the city of Duesseldorf, which is highly frequented by road traffic with an daily amount of about 45,000 vehicles. The street is located within the low emission zone (LEZ). Additionally the pass through of vehicles with a higher weight than 7.5 tons is prohibited. Within this study over a period of several weeks the particle mass concentrations PM10, PM2.5 and PM1, and the particle number size distribution (PNSD) were measured over a broad range from 5 nm to 32 µm with a high temporal resolution. Additionally, an aethalometer was used to determine the proportion of black carbon in the particle ensembles. Gaseous pollutants like nitrogen dioxide, ozone and sulphur dioxide were measured as well. Nitrogen dioxide is a typical species originating from combustion processes. In this study the data from NO2 strongly correlate with ultrafine particle and black carbon concentrations and for this reason all three species are clearly influenced by road traffic. However, this effect is not so pronounced for the particle mass concentrations, which are additionally influenced by the varying local background concentrations. During the measurements, the averaged concentration for PM10 was on a moderate level at 20.6 µg/m³ (PM2.5 13.4 µg/m³, PM1 10.7 µg/m³). The averaged NO2 concentration was 54.2 µg/m³ during the measurement period, which is above the yearly limit value of 40 µg/m³. However, the hourly limit value of 200 µg/m³ was not exceeded during the measurement period of this study. The averaged particle number concentration (PNC5-250 nm) and black carbon concentration were on a low level compared with values from other studies at roadsides. The PNC5-250 nm was at 6,400 \#/cm³ and for black carbon at 1.8 µg/m³. The lower values for PNC and BC are possibly explained as a result due to the measures from the clean air plan. The measurements of this study took place in summertime. The air pollution concentrations might be higher during colder times of the year due to domestic fuel burning. After all it can be stated, that the additional monitoring of ultrafine particles and black carbon is relevant and important to characterize the composition of the air quality at roadsides and offer a better understanding for the temporal resolution of air pollutants in cities. Moreover, estimations on the risk of air pollution for the human health can more precisely be specified.}, language = {en} } @article{WeberHewelingFischeretal.2017, author = {Weber, Konradin and Heweling, Georg and Fischer, Christian and Lange, Martin}, title = {The use of an octocopter UAV for the determination of air pollutants - a case study of the traffic induced pollution plume around a river bridge in Duesseldorf, Germany}, series = {International Journal of Environmental Science}, volume = {2}, journal = {International Journal of Environmental Science}, issn = {2367-8941}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-50805}, pages = {63 -- 66}, year = {2017}, abstract = {Emissions of air pollutants from the road traffic are still a major problem in Germany. It is well known that traffic induced fine particulate matter (PM10, PM2.5, PM1), ultrafine particles (UFPs) and gaseous air pollutants, like e.g. NOx, are adverse to human health. Therefore it is important to monitor these air pollutants in the cities. In this study an octocopter UAV is used as a carrier for measurement systems for UFPs, fine particulate matter and soot. This instrumented octocopter was used for studying the vertical and horizontal variation of the air pollution plume, which originated from the traffic on a river bridge, connecting two parts of Duesseldorf in Germany. This octocopter UAV had been especially designed and built at the Duesseldorf University of Applied Sciences for measurements of air pollutants. It was featuring eight 900 W electric propeller drives and was equipped with a pixhawk flight control. Its lift off weight was about 10.5 kg. About 60 measurement flights were performed by the instrumented octocopter throughout this study. These measurement flights could clearly determine the traffic induced air pollution plume originating from the bridge. Moreover, the dispersion of UFPs within the pollution plume could be monitored with the octocopter flights.}, subject = {Flugk{\"o}rper}, language = {en} } @article{HeninPetitRohwetteretal.2011, author = {Henin, Stefano and Petit, Yannick and Rohwetter, Philipp and Stelmaszczyk, Kamil and Hao, Zuoqiang and Nakaema, Walter Morinobu and Vogel, Andreas and Pohl, Tobias and Schneider, Friedhelm and Kasparian, J{\´e}r{\^o}me and Weber, Konradin and W{\"o}ste, Ludger and Wolf, Jean-Pierre}, title = {Field measurements suggest the mechanism of laser-assisted water condensation}, series = {Nature Communications}, volume = {2}, journal = {Nature Communications}, number = {1}, publisher = {Springer Nature}, issn = {2041-1723}, doi = {10.1038/ncomms1462}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-52439}, year = {2011}, abstract = {Because of the potential impact on agriculture and other key human activities, efforts have been dedicated to the local control of precipitation. The most common approach consists of dispersing small particles of dry ice, silver iodide, or other salts in the atmosphere. Here we show, using field experiments conducted under various atmospheric conditions, that laser filaments can induce water condensation and fast droplet growth up to several μm in diameter in the atmosphere as soon as the relative humidity exceeds 70\%. We propose that this effect relies mainly on photochemical formation of p.p.m.-range concentrations of hygroscopic Hno3, allowing efficient binary Hno3-H2o condensation in the laser filaments. Thermodynamic, as well as kinetic, numerical modelling based on this scenario semiquantitatively reproduces the experimental results, suggesting that particle stabilization by Hno3 has a substantial role in the laser-induced condensation.}, subject = {Kondensation}, language = {en} }