TY - JOUR A1 - Carapezza, M. L. A1 - Barberi, F. A1 - Ranaldi, M. A1 - Ricci, T. A1 - Tarchini, L. A1 - Barrancos, José A1 - Fischer, C. A1 - Perez, N. A1 - Weber, Konradin A1 - Di Piazza, A. A1 - Gattuso, A. T1 - Diffuse CO2 soil degassing and CO2 and H2S concentrations in air and related hazards at Vulcano Island (Aeolian arc, Italy) JF - Journal of Volcanology and Geothermal Research Y1 - 2011 U6 - https://doi.org/10.1016/j.jvolgeores.2011.06.010 VL - 207 IS - 3-4 SP - 130 EP - 144 PB - Elsevier ER - TY - JOUR A1 - Elíasson, Jónas A1 - Palsson, Asgeir A1 - Weber, Konradin T1 - Monitoring ash clouds for aviation JF - Nature KW - Luftreinhaltung Y1 - 2011 U6 - https://doi.org/10.1038/475455b VL - 475 IS - 7357 PB - Springer Nature ER - TY - JOUR A1 - Petrarca, M. A1 - Henin, S. A1 - Stelmaszczyk, K. A1 - Bock, S. A1 - Kraft, S. A1 - Schramm, U. A1 - Vaneph, C. A1 - Vogel, A. A1 - Kasparian, J. A1 - Sauerbrey, R. A1 - Weber, Konradin A1 - Wöste, L. A1 - Wolf, J.-P. T1 - Multijoule scaling of laser-induced condensation in air JF - Applied Physics Letters N2 - 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. KW - Luftreinhaltung Y1 - 2011 U6 - https://doi.org/10.1063/1.3646397 SN - 0003-6951 VL - 99 IS - 14 PB - AIP Publishing ER - TY - JOUR A1 - Petit, Y. A1 - Henin, S. A1 - Kasparian, J. A1 - Wolf, J. P. A1 - Rohwetter, P. A1 - Stelmaszczyk, K. A1 - Hao, Z. Q. A1 - Nakaema, W. M. A1 - Wöste, L. A1 - Vogel, A. A1 - Pohl, T. A1 - Weber, Konradin T1 - Influence of pulse duration, energy, and focusing on laser-assisted water condensation JF - Applied Physics Letters N2 - 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. KW - Luftreinhaltung Y1 - 2011 U6 - https://doi.org/10.1063/1.3546172 SN - 0003-6951 VL - 98 IS - 4 PB - AIP Publishing ER - TY - CHAP A1 - Vogel, Andreas A1 - Weber, Konradin A1 - Fischer, Christian A1 - van Haren, Günther A1 - Pohl, Tobias A1 - Grobety, Bernhard A1 - Meier, Mario T1 - Airborne in-situ measurements of the Eyjafjallojökull ash plume with a small aircraft and optical particle spectrometers over north-western Germany - comparison between the aircraft measurements and the VAAC-model calculations T2 - Geophysical Research Abstracts: EGU General Assembly 2011 N2 - The eruption of the volcano Eyjafjallajökull (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 KW - Luftreinhaltung KW - Vulkanasche KW - Atmosphärisches Aerosol KW - Eyjafjallajökull KW - Messtechnik Y1 - 2011 VL - 13 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Henin, Stefano A1 - Petit, Yannick A1 - Rohwetter, Philipp A1 - Stelmaszczyk, Kamil A1 - Hao, Zuoqiang A1 - Nakaema, Walter Morinobu A1 - Vogel, Andreas A1 - Pohl, Tobias A1 - Schneider, Friedhelm A1 - Kasparian, Jérôme A1 - Weber, Konradin A1 - Wöste, Ludger A1 - Wolf, Jean-Pierre T1 - Field measurements suggest the mechanism of laser-assisted water condensation JF - Nature Communications N2 - 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. KW - Luftreinhaltung KW - Kondensation KW - Laser KW - Niederschlag Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-52439 SN - 2041-1723 VL - 2 IS - 1 PB - Springer Nature ER -