@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{PetrarcaHeninStelmaszczyketal.2011, author = {Petrarca, M. and Henin, S. and Stelmaszczyk, K. and Bock, S. and Kraft, S. and Schramm, U. and Vaneph, C. and Vogel, A. and Kasparian, J. and Sauerbrey, R. and Weber, Konradin and W{\"o}ste, L. and Wolf, J.-P.}, title = {Multijoule scaling of laser-induced condensation in air}, series = {Applied Physics Letters}, volume = {99}, journal = {Applied Physics Letters}, number = {14}, publisher = {AIP Publishing}, issn = {0003-6951}, doi = {10.1063/1.3646397}, year = {2011}, abstract = {Using 100 TW laser pulses, we demonstrate that laser-induced nanometric particle generation in air increases much faster than the beam-averaged incident intensity. This increase is due to a contribution from the photon bath, which adds up with the previously identified one from the filaments and becomes dominant above 550 GW/cm2. It appears related to ozone formation via multiphoton dissociation of the oxygen molecules and demonstrates the critical need for further increasing the laser energy in view of macroscopic effects in laser-induced condensation.}, 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} }