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 - Elíasson, Jonas A1 - Weber, Konradin A1 - Vogel, Andreas A1 - Pálsson, Thorgeir A1 - Yoshitani, Junichi A1 - Miki, Daisuke T1 - Investigation and Separation of Turbulent Fluctuations in Airborne Measurements of Volcanic Ash with Optical Particle Counters JF - Journal of Disaster Research N2 - 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. KW - Luftreinhaltung Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-50023 SN - 1883-8030 VL - 11 IS - 1 SP - 72 EP - 84 PB - Fuji Technology Press Ltd. ER - TY - JOUR A1 - Elíasson, Jonas A1 - Yoshitani, Junichi A1 - Miki, Daisuke A1 - Weber, Konradin A1 - Bölke, Christoph A1 - Scharifi, Emad T1 - Measurements of Particle Distribution and Ash Fluxes in the Plume of Sakurajima Volcano with Optical Particle Counter JF - Journal of Disaster Research N2 - 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 (Eyjafjallajökull) and 2011 (Grímsvötn). 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. KW - Luftreinhaltung Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-50030 SN - 1883-8030 VL - 11 IS - 1 SP - 85 EP - 95 PB - Fuji Technology Press Ltd. ER - TY - CHAP A1 - Weber, Konradin A1 - Eliasson, Jonas A1 - Arnason, Gylfi A1 - Rögnvaldsson, Ólafur A1 - Thorsteinsson, Throstur A1 - Palsson, Thorgeir A1 - Böhlke, Christoph A1 - Fischer, Christian A1 - Smith, Paul A1 - Jones, Roderic L. A1 - Tirpitz, Lukas A1 - Platt, Ulrich T1 - Airborne Investigations and WRF - Model Calculations of the Bardarbunga-Holuhraun Eruption Plume T2 - Geophysical Research Abstracts: EGU General Assembly 2015 N2 - The eruption in Holuhraun is the largest producer of lava and gas in Iceland since 1783. The Volcanic Ash Research (VAR) group organized an airborne measurement campaign including 10 flights, where emissions of SO2 and ash concentrations were measured at the source and at the far plume. The highest SO2 concentration at the source was nearly up to 100 mg/m3. This is an extremely high value, compared to other airborne campaigns and a contamination considered to cause serious illness by the Icelandic Directorate of Health. Volcanic ash consisted of very fine particles, but the concentration was low when compared to other recent eruptions. Measurements of the far plume showed that scavenging is very active. The dispersion was successfully modeled with the Weather Research and Foreast (WRF-chem) model and analysis using the model showed that a large amount of the sulphur was precipitated in the Icelandic highlands. KW - Luftreinhaltung KW - Vulkanismus KW - Vulkanasche KW - Messtechnik KW - Atmosphärisches Aerosol KW - Schwefeldioxid Y1 - 2015 UR - https://web.archive.org/web/20240719170649/https://meetingorganizer.copernicus.org/EGU2015/EGU2015-10846-1.pdf N1 - Vortragsabstract VL - 17 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Eliasson, Jonas A1 - Yoshitani, Junichi A1 - Weber, Konradin A1 - Yasuda, Nario A1 - Iguchi, Masato A1 - Vogel, Andreas T1 - Airborne Measurement in the Ash Plume from Mount Sakurajima: Analysis of Gravitational Effects on Dispersion and Fallout JF - International Journal of Atmospheric Sciences N2 - Volcanic ash concentrations in the plume from Sakurajima volcano in Japan are observed from airplanes equipped with optical particle counters and GPS tracking devices. The volcano emits several puffs a day. The puffs are also recorded by the Sakurajima Volcanological Observatory. High concentrations are observed in the puffs and fallout driven by vertical air current, called streak fallout. Puffs dispersion is analyzed by the classical diffusion-advection method and a new gravitational dispersion method. The fluid mechanic of the gravitational dispersion, streak fallout, and classical diffusion-advection theory is described in three separate appendices together with methods to find the time gravitational dispersion constant and the diffusion coefficient from satellite photos. The diffusion-advection equation may be used to scale volcanic eruptions so the same eruption plumes can be scaled to constant flux and wind conditions or two eruptions can be scaled to each other. The dispersion analyses show that dispersion of volcanic plumes does not follow either theories completely. It is most likely diffusion in the interface of the plume and the ambient air, together with gravitational flattening of the plumes core. This means larger boundary concentration gradients and smaller diffusion coefficients than state of the art methods can predict. KW - Luftreinhaltung KW - Vulkanismus KW - Vulkanasche KW - Messtechnik KW - Atmosphärisches Aerosol Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-50955 SN - 2314-4122 VL - 2014 PB - Wiley ER - TY - CHAP A1 - Weber, Konradin A1 - Fischer, Christian A1 - Vogel, Andreas A1 - Pohl, Tobias A1 - Böhlke, Christoph A1 - Lau, Hendrik A1 - Eliasson, Jonas A1 - Palsson, Thorgeir ED - Mladenov, Valeri ED - Tasho, Tashev ED - Hui, Wang ED - Ivan, Kralov ED - Sergey, Stankevich ED - Pelin, Yildiz ED - Jon, Burley T1 - First results of an airborne release of volcanic ash for testing of volcanic ash plume measurement instruments T2 - Recent Advances in Energy and Environmental Management KW - Luftreinhaltung KW - Vulkanasche KW - Messtechnik KW - Forschungsflugzeug Y1 - 2013 VL - Energy, Environmental and Structural Engineering Series 13 SP - 169 EP - 172 PB - WSEAS ER - TY - JOUR A1 - Eliasson, Jonas A1 - Yasuda, Nario A1 - Weber, Konradin A1 - Vogel, Andreas A1 - Palsson, Thorgeir T1 - The role of in-situ measurements of volcanic ash concentrations in preventing economic disasters due to volcanic ash clouds JF - Journal of Integrated Disaster Risk Management KW - Luftreinhaltung Y1 - 2014 UR - https://www.idrimjournal.com/article/11691-the-role-of-in-situ-measurements-of-volcanic-ash-concentrations-in-preventing-economic-disasters-due-to-volcanic-ash-clouds U6 - https://doi.org/10.5595/idrim.2014.0092 SN - 2185-8322 VL - 4 IS - 1 SP - 48 EP - 60 PB - Journal of Integrated Disaster Risk Management ER - TY - CHAP A1 - Eliasson, Jonas A1 - Palsson, Thorgeir A1 - Weber, Konradin T1 - State of volcanic ash dispersion prediction T2 - Geophysical Research Abstracts: EGU General Assembly 2017 N2 - The Eyjafjallajokull 2010 and Grimsvotn 2011 eruptions created great problems for commercial aviation in Western Europe and in the North Atlantic region. Comparison of satellite images of the visible and predicted ash clouds showed the VAAC prediction to be much larger than the actual ash clouds. No official explanation of this discrepancy exists apart from the definition of the ash cloud boundary. Papers on simulation of the Eyjafjallajökull ash cloud in peer reviewed journals, typically attempted to simulate the VAAC predictions rather than focusing on the satellite pictures. Sporadic measurements made in-situ showed much lower ash concentrations over Europe than the predicted values. Two of the weak points in ash cloud prediction have been studied in airborne measurements of volcanic ash by the Universities in Kyoto Japan, Iceland and Düsseldorf Germany of eruptions in Sakurajima, Japan. It turns out that gravitational deformation of the plume and a streak fallout process make estimated ash content of clouds larger than the actual, both features are not included in the simulation model. Tropospheric plumes tend to ride in stable inversions this causes gravitational flattening (pancaking) of the volcanic plume, while diffusion in the mixing layer is insignificant. New rules from ICAO, effective from November 2014, reiterate that jetliners should avoid visible ash, this makes information on visible ash important. A procedure developed by JMA′s Tokyo VAAC uses satellite images of visible ash to correct the prediction. This and the fact that meteorological data necessary to model gravitational dispersion and streak fallout do not exist in the international database available to the VAAC′s. This shows that close monitoring by airborne measurements and satellite and other photographic surveillance is necessary. KW - Luftreinhaltung KW - Vulkanismus KW - Vulkanasche KW - Luftfahrt KW - Messtechnik Y1 - 2017 UR - https://web.archive.org/web/20220725214514/https://meetingorganizer.copernicus.org/EGU2017/EGU2017-13656.pdf PB - Copernicus CY - Göttingen ER - TY - CHAP A1 - Arnason, Gylfi A1 - Eliasson, Jonas A1 - Weber, Konradin A1 - Böhlke, Christoph A1 - Palsson, Thorgeir A1 - Rögnvaldsson, Ólafur A1 - Thorsteinsson, Throstur A1 - Platt, Ulrich A1 - Tirpitz, Lukas A1 - Jones, Roderic L. A1 - Smith, Paul D. T1 - Results of airborne measurements in the plume near and far from the 2014 Bardarbunga-Holuhraun eruption T2 - Geophysical Research Abstracts: EGU General Assembly 2015 N2 - 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. KW - Luftreinhaltung KW - Vulkanasche KW - Vulkanismus KW - Atmosphärisches Aerosol KW - Messtechnik Y1 - 2015 N1 - Vortragsabstract VL - 17 PB - Copernicus CY - Göttingen ER - TY - CHAP A1 - Rögnvaldsson, Ólafur A1 - Arnason, Gylfi A1 - Palsson, Thorgeir A1 - Eliasson, Jonas A1 - Weber, Konradin A1 - Böhlke, Christoph A1 - Thorsteinsson, Throstur A1 - Tirpitz, Lukas A1 - Platt, Ulrich A1 - Smith, Paul D. A1 - Jones, Roderic L. T1 - Modeling of SO2 dispersion from the 2014 Holuhraun eruption in Iceland using WRF-Chem T2 - Geophysical Research Abstracts: EGU General Assembly 2015 N2 - 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. KW - Luftreinhaltung KW - Vulkanismus KW - Schwefeldioxid KW - Messtechnik Y1 - 2015 UR - https://web.archive.org/web/20240615204204/https://meetingorganizer.copernicus.org/EGU2015/EGU2015-10113.pdf N1 - Vortragsabstract VL - 17 PB - Copernicus CY - Göttingen ER -