@article{CarapezzaBarberiRanaldietal.2012, author = {Carapezza, M. L. and Barberi, F. and Ranaldi, M. and Ricci, T. and Tarchini, L. and Barrancos, Jos{\´e} and Fischer, C. and Granieri, D. and Lucchetti, C. and Melian, G. and Perez, N. and Tuccimei, P. and Vogel, A. and Weber, Konradin}, title = {Hazardous gas emissions from the flanks of the quiescent Colli Albani volcano (Rome, Italy)}, series = {Applied Geochemistry}, volume = {27}, journal = {Applied Geochemistry}, number = {9}, publisher = {Elsevier}, doi = {10.1016/j.apgeochem.2012.02.012}, pages = {1767 -- 1782}, year = {2012}, language = {en} } @article{StrucksWatermannWeberetal.2021, author = {Strucks, Peter and Watermann, Clara and Weber, Konradin and Kaluza, Stefan}, title = {Systematic Investigations of Vibrational and Fluid-Mechanical Stability of Coated Monolithic Catalysts}, series = {Chemie Ingenieur Technik}, volume = {93}, journal = {Chemie Ingenieur Technik}, number = {5}, publisher = {Wiley}, issn = {1522-2640}, doi = {10.1002/cite.202000233}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-28930}, pages = {1 -- 6}, year = {2021}, abstract = {Heterogeneous catalysts usually consist of porous, inorganic materials. Especially in the mobile application, e.g., in exhaust gas catalysis as a part of the gas line of an engine, there are loads due to vibrations and high gas velocities. It can be assumed that physical stress will lead to a loss of the catalytically active coating. The present contribution describes experimental setups and methods for a systematic and reproducible investigation of the main influences to the mass loss due to vibrational and fluid-mechanical stress caused by particle-free gas flows.}, language = {en} } @article{PrataDezitterDaviesetal.2016, author = {Prata, A. J. and Dezitter, F. and Davies, I. and Weber, Konradin and Birnfeld, M. and Moriano, D. and Bernardo, C. and Vogel, A. and Prata, G. S. and Mather, T. A. and Thomas, H. E. and Cammas, J. and Weber, M.}, title = {Artificial cloud test confirms volcanic ash detection using infrared spectral imaging}, series = {Scientific reports}, volume = {6}, journal = {Scientific reports}, publisher = {Springer Nature}, doi = {10.1038/srep25620}, year = {2016}, abstract = {Airborne volcanic ash particles are a known hazard to aviation. Currently, there are no means available to detect ash in flight as the particles are too fine (radii < 30 μm) for on-board radar detection and, even in good visibility, ash clouds are difficult or impossible to detect by eye. The economic cost and societal impact of the April/May 2010 Icelandic eruption of Eyjafjallaj{\"o}kull generated renewed interest in finding ways to identify airborne volcanic ash in order to keep airspace open and avoid aircraft groundings. We have designed and built a bi-spectral, fast-sampling, uncooled infrared camera device (AVOID) to examine its ability to detect volcanic ash from commercial jet aircraft at distances of more than 50 km ahead. Here we report results of an experiment conducted over the Atlantic Ocean, off the coast of France, confirming the ability of the device to detect and quantify volcanic ash in an artificial ash cloud created by dispersal of volcanic ash from a second aircraft. A third aircraft was used to measure the ash in situ using optical particle counters. The cloud was composed of very fine ash (mean radii ~10 μm) collected from Iceland immediately after the Eyjafjallaj{\"o}kull eruption and had a vertical thickness of ~200 m, a width of ~2 km and length of between 2 and 12 km. Concentrations of ~200 μg m(-3) were identified by AVOID at distances from ~20 km to ~70 km. For the first time, airborne remote detection of volcanic ash has been successfully demonstrated from a long-range flight test aircraft.}, language = {en} } @article{BirmiliRehnVogeletal.2013, author = {Birmili, Wolfram and Rehn, Johanna and Vogel, Andreas and Boehlke, Christoph and Weber, Konradin and Rasch, Fabian}, title = {Micro-scale variability of urban particle number and mass concentrations in Leipzig, Germany}, series = {Meteorologische Zeitschrift}, volume = {22}, journal = {Meteorologische Zeitschrift}, number = {2}, publisher = {Borntr{\"a}ger}, doi = {10.1127/0941-2948/2013/0394}, pages = {155 -- 165}, year = {2013}, language = {en} } @article{JolyPetrarcaVogeletal.2013, author = {Joly, P. and Petrarca, M. and Vogel, A. and Pohl, T. and Nagy, T. and Jusforgues, Q. and Simon, P. and Kasparian, J. and Weber, K. and Wolf, J.-P.}, title = {Laser-induced condensation by ultrashort laser pulses at 248 nm}, series = {Applied Physics Letters}, volume = {102}, journal = {Applied Physics Letters}, number = {9}, publisher = {AIP}, doi = {10.1063/1.4794416}, year = {2013}, language = {en} } @article{EliassonPalssonWeber2011, author = {El{\´i}asson, J{\´o}nas and Palsson, Asgeir and Weber, Konradin}, title = {Monitoring ash clouds for aviation}, series = {Nature}, volume = {475}, journal = {Nature}, number = {7357}, publisher = {Springer Nature}, doi = {10.1038/475455b}, pages = {455}, year = {2011}, language = {en} } @incollection{EliassonWatsonWeber2016, author = {Eliasson, J. and Watson, I.M. and Weber, Konradin}, title = {In Situ Observations of Airborne Ash From Manned Aircraft}, series = {Volcanic Ash}, booktitle = {Volcanic Ash}, publisher = {Elsevier}, isbn = {9780081004050}, doi = {10.1016/B978-0-08-100405-0.00009-4}, pages = {89 -- 98}, year = {2016}, language = {en} } @inproceedings{ComeronKassianovSchaeferetal.2015, author = {Comeron, Adolfo and Kassianov, Evgueni I. and Sch{\"a}fer, Klaus and Picard, Richard H. and Weber, Konradin}, title = {Remote Sensing of Clouds and the Atmosphere XX. Remote Sensing of Clouds and the Atmosphere, Toulouse), 23.-24.09.2015}, volume = {Proceedings of SPIE ; volume 9640}, publisher = {SPIE}, address = {Bellingham, Washington, USA}, isbn = {978-1-62841-850-7}, issn = {0277-786X}, year = {2015}, language = {en} } @article{MoxnesKristiansenStohletal.2014, author = {Moxnes, E. D. and Kristiansen, N. I. and Stohl, A. and Clarisse, L. and Durant, A. and Weber, Konradin and Vogel, A.}, title = {Separation of ash and sulfur dioxide during the 2011 Gr{\´i}msv{\"o}tn eruption}, series = {Journal of Geophysical Research: Atmospheres}, volume = {119}, journal = {Journal of Geophysical Research: Atmospheres}, number = {12}, publisher = {American Geophysical Union (AGU)}, issn = {2169-8996}, doi = {10.1002/2013JD021129}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-50162}, pages = {7477 -- 7501}, year = {2014}, language = {en} } @article{LeadbetterHortvonLoewisetal.2012, author = {Leadbetter, S. J. and Hort, M. C. and von L{\"o}wis, S. and Weber, Konradin and Witham, C. S.}, title = {Modeling the resuspension of ash deposited during the eruption of Eyjafjallaj{\"o}kull in spring 2010}, series = {Journal of Geophysical Research: Atmospheres}, volume = {117}, journal = {Journal of Geophysical Research: Atmospheres}, number = {D20}, publisher = {American Geophysical Union (AGU)}, issn = {0148-0227}, doi = {10.1029/2011JD016802}, year = {2012}, abstract = {Eyjafjallaj{\"o}kull, a volcano in southern Iceland, erupted explosively in April and May 2010 depositing ash over a region of more than 3000 km2 to the east and southeast of the volcano. This deposited ash has been frequently remobilized by the wind causing concern for the health of Icelanders living in the region. An investigation was carried out to determine whether it would be possible to produce forecasts of days when high airborne ash concentrations were likely to occur. Information about the spatially varying surface characteristics of the region of deposited ash is not available so in the modeling approach adopted here ash is released from the surface at a rate proportional to the cube of the excess friction velocity (local friction velocity minus a threshold) only when the friction velocity exceeds a threshold. Movement of the resuspended ash is then modeled in a Lagrangian dispersion model. Modeled ash concentrations are compared to observed concentrations from two periods; PM10 observations between 23 May and 2 July 2010 and airborne particle counts between 21 September 2010 and 16 February 2011. More than 66\% of the resuspension episodes between May and July are captured by the model and the relative magnitudes of the modeled episodes in this period are in good agreement with the observations. 66\% of episodes between October and February are also captured by the model although there is an increase in the false alarm rate which appears to be due to the influence of precipitation.}, language = {en} } @inproceedings{FischerPohlWeberetal.2012, author = {Fischer, C. and Pohl, T. and Weber, Konradin and Vogel, A. and van Haren, G. and Schweikert, W.}, title = {TATP stand-off detection with open path: FTIR techniques}, series = {Optics and photonics for counterterrorism, crime fighting and defence VIII : 24 - 26 September 2012, Edinburgh, United Kingdom}, volume = {8546}, booktitle = {Optics and photonics for counterterrorism, crime fighting and defence VIII : 24 - 26 September 2012, Edinburgh, United Kingdom}, editor = {Lewis, Colin and Burgess, Douglas}, publisher = {SPIE}, address = {Bellingham, Wash}, isbn = {978-0-8194-9287-6}, issn = {0277-786X}, doi = {10.1117/12.974592}, year = {2012}, language = {en} } @article{NaraparajuLauLangeetal.2018, author = {Naraparaju, R. and Lau, H. and Lange, Martin and Fischer, Christian and Kramer, D. and Schulz, U. and Weber, Konradin}, title = {Integrated testing approach using a customized micro turbine for a volcanic ash and CMAS related degradation study of thermal barrier coatings}, series = {Surface and Coatings Technology}, volume = {337}, journal = {Surface and Coatings Technology}, publisher = {Elsevier}, issn = {0257-8972}, doi = {10.1016/j.surfcoat.2018.01.030}, pages = {198 -- 208}, year = {2018}, language = {en} } @inproceedings{MaasHoefertSchaeferetal.2018, author = {Maas, Peter and H{\"o}fert, Norbert and Sch{\"a}fer, Klaus and Weber, Konradin and Richter, Andreas}, title = {Standards VDI 4211 and VDI 4212 on passive FTIR and DOAS remote sensing techniques}, series = {Proceedings Volume 10786, Remote Sensing of Clouds and the Atmosphere XXIII; 107860W (2018)}, booktitle = {Proceedings Volume 10786, Remote Sensing of Clouds and the Atmosphere XXIII; 107860W (2018)}, editor = {Comer{\´o}n, Adolfo and Kassianov, Evgueni I. and Sch{\"a}fer, Klaus and Picard, Richard H. and Weber, Konradin}, publisher = {SPIE}, doi = {10.1117/12.2325145}, year = {2018}, language = {en} } @article{EliassonWeberVogeletal.2016, author = {El{\´i}asson, Jonas and Weber, Konradin and Vogel, Andreas and P{\´a}lsson, Thorgeir and Yoshitani, Junichi and Miki, Daisuke}, title = {Investigation and Separation of Turbulent Fluctuations in Airborne Measurements of Volcanic Ash with Optical Particle Counters}, series = {Journal of Disaster Research}, volume = {11}, journal = {Journal of Disaster Research}, number = {1}, publisher = {Fuji Technology Press Ltd.}, issn = {1883-8030}, doi = {10.20965/jdr.2016.p0072}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-50023}, pages = {72 -- 84}, year = {2016}, abstract = {The science of measuring airborne volcanic ash concentrations supports research in such fields as atmospheric environmental science and the modeling of atmospheric pollution from volcanoes, and is thus very valuable to the aviation industry. These measurements show large scatter directly traceable to turbulent fluctuations responsible for diffusing volcanic dust. Before semistationary components in observations can be compared to each other or to simulation results, they must be separated from fluctuations. In the design of the separation process, however, neither seasonal or diurnal periodicity nor random disturbance with known properties exists to serve as a guideline. It has been suggested that fluctuations could be eliminated through repeated convolutions of a simple 3-point filter enough times. The number of convolutions is chosen from the change in the rate of increase of a special variability parameter. When semistationary concentrations are separated from fluctuations, their statistics are compared to turbulence parameters and the autocorrelation of the series. The method is demonstrated using three measurement series from Sakurajima, Japan measured in 2013. It is concluded that this new method is simple and trustworthy where knowledge and experience of the environmental parameters can be utilized to support the results. They indicate a variability of 40\% in the relative fluctuations of the PM10 and around 20\% of the PM2.5. The relative fluctuations may be considered completely random, but normally distributed rather than a white noise with an evenly distributed variance spectrum.}, language = {en} } @article{EliassonYoshitaniMikietal.2016, author = {El{\´i}asson, Jonas and Yoshitani, Junichi and Miki, Daisuke and Weber, Konradin and B{\"o}lke, Christoph and Scharifi, Emad}, title = {Measurements of Particle Distribution and Ash Fluxes in the Plume of Sakurajima Volcano with Optical Particle Counter}, series = {Journal of Disaster Research}, volume = {11}, journal = {Journal of Disaster Research}, number = {1}, publisher = {Fuji Technology Press Ltd.}, issn = {1883-8030}, doi = {10.20965/jdr.2016.p0085}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-50030}, pages = {85 -- 95}, year = {2016}, abstract = {Volcanic eruptions have caused very costly disturbances of international air traffic. This problem has been dealt with by simulating the formation and migration of dangerous ash plumes. However, the results of the simulations have sometimes been too safe, producing ash clouds that are too large. This was especially the case for the North Atlantic in 2010 (Eyjafjallaj{\"o}kull) and 2011 (Gr{\´i}msv{\"o}tn). Since 2012, an international cooperation team led by the Disaster Prevention Research Institute (DPRI) of Kyoto University has conducted airborne measurements of volcanic ash concentrations in the plume from Mount Sakurajima in Kagoshima Prefecture, Japan. This volcano was chosen because of its frequent but limited eruptions, which allow close observation. These measurement campaigns have provided data showing gravitational flattening of the plume, a new and previously unknown dispersion process of volcanic plumes. A new and previously unknown fallout process, called streak fallout, also has been measured. Results concerning plume flux, concentration distributions, aerosol (PM10) content of the plume, and content of very fine particles (PM2.5 and PM1) are presented, and the ways by which the observational methods can be used to produce reliable initial data and boundary values for simulations of plume dispersion are discussed.}, language = {en} } @inproceedings{ComeronJackKassianovetal.2016, author = {Comeron, Adolfo and Jack, James and Kassianov, Evgueni I. and Sch{\"a}fer, Kiaus and Picard, Richard H and Weber, Konradin}, title = {Remote Sensing of Clouds and the Atmosphere XXI Introduction}, series = {Remote Sensing of Clouds and the Atmosphere XXI : 28-29 September 2016, Edinburgh, United Kingdom}, booktitle = {Remote Sensing of Clouds and the Atmosphere XXI : 28-29 September 2016, Edinburgh, United Kingdom}, publisher = {SPIE}, address = {Bellingham, Washington, USA}, isbn = {978-1-5106-0406-3}, year = {2016}, language = {en} } @article{FuHeeminkLuetal.2016, author = {Fu, Guangliang and Heemink, Arnold and Lu, Sha and Segers, Arjo and Weber, Konradin and Lin, Hai-Xiang}, title = {Model-based aviation advice on distal volcanic ash clouds byassimilating aircraft in situ measurements}, series = {Atmospheric Chemistry and Physics}, volume = {16}, journal = {Atmospheric Chemistry and Physics}, number = {14}, publisher = {Copernicus}, issn = {1680-7324}, doi = {10.5194/acp-16-9189-2016}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-50058}, pages = {9189 -- 9200}, year = {2016}, abstract = {Abstract. The forecast accuracy of distal volcanic ash clouds is important for providing valid aviation advice during volcanic ash eruption. However, because the distal part of volcanic ash plume is far from the volcano, the influence of eruption information on this part becomes rather indirect and uncertain, resulting in inaccurate volcanic ash forecasts in these distal areas. In our approach, we use real-life aircraft in situ observations, measured in the northwestern part of Germany during the 2010 Eyjafjallaj{\"o}kull eruption, in an ensemble-based data assimilation system combined with a volcanic ash transport model to investigate the potential improvement on the forecast accuracy with regard to the distal volcanic ash plume. We show that the error of the analyzed volcanic ash state can be significantly reduced through assimilating real-life in situ measurements. After a continuous assimilation, it is shown that the aviation advice for Germany, the Netherlands and Luxembourg can be significantly improved. We suggest that with suitable aircrafts measuring once per day across the distal volcanic ash plume, the description and prediction of volcanic ash clouds in these areas can be greatly improved.}, language = {en} } @article{BonnvonSchneidemesserAndrichetal.2016, author = {Bonn, Boris and von Schneidemesser, Erika and Andrich, Dorota and Quedenau, J{\"o}rn and Gerwig, Holger and L{\"u}decke, Anja and Kura, J{\"u}rgen and Pietsch, Axel and Ehlers, Christian and Klemp, Dieter and Kofahl, Claudia and Nothard, Rainer and Kerschbaumer, Andreas and Junkermann, Wolfgang and Grote, R{\"u}diger and Pohl, Tobias and Weber, Konradin and Lode, Birgit and Sch{\"o}nberger, Philipp and Churkina, Galina and Butler, Tim M. and Lawrence, Mark G.}, title = {BAERLIN2014 - the influence of land surface types on and the horizontal heterogeneity of air pollutant levels in Berlin}, series = {Atmospheric Chemistry and Physics}, volume = {16}, journal = {Atmospheric Chemistry and Physics}, number = {12}, publisher = {Copernicus}, issn = {1680-7324}, doi = {10.5194/acp-16-7785-2016}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-50065}, pages = {7785 -- 7811}, year = {2016}, abstract = {Abstract. Urban air quality and human health are among the key aspects of future urban planning. In order to address pollutants such as ozone and particulate matter, efforts need to be made to quantify and reduce their concentrations. One important aspect in understanding urban air quality is the influence of urban vegetation which may act as both emitter and sink for trace gases and aerosol particles. In this context, the "Berlin Air quality and Ecosystem Research: Local and long-range Impact of anthropogenic and Natural hydrocarbons 2014" (BAERLIN2014) campaign was conducted between 2 June and 29 August in the metropolitan area of Berlin and Brandenburg, Germany. The predominant goals of the campaign were (1) the characterization of urban gaseous and particulate pollution and its attribution to anthropogenic and natural sources in the region of interest, especially considering the connection between biogenic volatile organic compounds and particulates and ozone; (2) the quantification of the impact of urban vegetation on organic trace gas levels and the presence of oxidants such as ozone; and (3) to explain the local heterogeneity of pollutants by defining the distribution of sources and sinks relevant for the interpretation of model simulations. In order to do so, the campaign included stationary measurements at urban background station and mobile observations carried out from bicycle, van and airborne platforms. This paper provides an overview of the mobile measurements (Mobile BAERLIN2014) and general conclusions drawn from the analysis. Bicycle measurements showed micro-scale variations of temperature and particulate matter, displaying a substantial reduction of mean temperatures and particulate levels in the proximity of vegetated areas compared to typical urban residential area (background) measurements. Van measurements extended the area covered by bicycle observations and included continuous measurements of O3, NOx, CO, CO2 and point-wise measurement of volatile organic compounds (VOCs) at representative sites for traffic- and vegetation-affected sites. The quantification displayed notable horizontal heterogeneity of the short-lived gases and particle number concentrations. For example, baseline concentrations of the traffic-related chemical species CO and NO varied on average by up to ±22.2 and ±63.5 \%, respectively, on the scale of 100 m around any measurement location. Airborne observations revealed the dominant source of elevated urban particulate number and mass concentrations being local, i.e., not being caused by long-range transport. Surface-based observations related these two parameters predominantly to traffic sources. Vegetated areas lowered the pollutant concentrations substantially with ozone being reduced most by coniferous forests, which is most likely caused by their reactive biogenic VOC emissions. With respect to the overall potential to reduce air pollutant levels, forests were found to result in the largest decrease, followed by parks and facilities for sports and leisure. Surface temperature was generally 0.6-2.1 °C lower in vegetated regions, which in turn will have an impact on tropospheric chemical processes. Based on our findings, effective future mitigation activities to provide a more sustainable and healthier urban environment should focus predominantly on reducing fossil-fuel emissions from traffic as well as on increasing vegetated areas.}, language = {en} } @article{WeberEliassonVogeletal.2012, author = {Weber, Konradin and Eliasson, J. and Vogel, A. and Fischer, C. and Pohl, T. and van Haren, G. and Meier, M. and Grob{\´e}ty, B. and Dahmann, D.}, title = {Airborne in-situ investigations of the Eyjafjallaj{\"o}kull volcanic ash plume on Iceland and over north-western Germany with light aircrafts and optical particle counters}, series = {Atmospheric Environment}, volume = {48}, journal = {Atmospheric Environment}, publisher = {Elsevier}, issn = {1352-2310}, doi = {10.1016/j.atmosenv.2011.10.030}, pages = {9 -- 21}, year = {2012}, language = {en} } @article{PetitHeninKasparianetal.2011, author = {Petit, Y. and Henin, S. and Kasparian, J. and Wolf, J. P. and Rohwetter, P. and Stelmaszczyk, K. and Hao, Z. Q. and Nakaema, W. M. and W{\"o}ste, L. and Vogel, A. and Pohl, T. and Weber, Konradin}, title = {Influence of pulse duration, energy, and focusing on laser-assisted water condensation}, series = {Applied Physics Letters}, volume = {98}, journal = {Applied Physics Letters}, number = {4}, publisher = {AIP Publishing}, issn = {0003-6951}, doi = {10.1063/1.3546172}, year = {2011}, abstract = {We investigate the influence of laser parameters on laser-assisted water condensation in the atmosphere. Pulse energy is the most critical parameter. Nanoparticle generation depends linearly on energy beyond the filamentation threshold. Shorter pulses are more efficient than longer ones with saturation at ∼1.5 ps. Multifilamenting beams appear more efficient than strongly focused ones in triggering the condensation and growth of submicronic particles, while polarization has a negligible influence on the process. The data suggest that the initiation of laser-assisted condensation relies on the photodissociation of the air molecules rather than on their photoionization.}, language = {en} }