title: Artificial cloud test confirms volcanic ash detection using infrared spectral imaging.
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 Eyjafjallajökull 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 Eyjafjallajökull 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.
authors.affiliation: Nicarnica Aviation AS, Vollsveien 9-11, N-1366, Lysaker, Norway.|Visiting scientist, Department of Atmospheric, Oceanic and Planetary Physics, University of Oxford, UK.
authors.forename: A J
authors.initials: AJ
authors.lastname: Prata
authors.affiliation: AIRBUS Operations SAS, Toulouse, France.
authors.forename: F
authors.initials: F
authors.lastname: Dezitter
authors.affiliation: easyJet plc, Luton, UK.
authors.forename: I
authors.initials: I
authors.lastname: Davies
authors.affiliation: Department for Mechanical Engineering, Düsseldorf University of Applied Sciences, Düsseldorf, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Weber
authors.affiliation: AIRBUS SAS, Toulouse, France.
authors.forename: M
authors.initials: M
authors.lastname: Birnfeld
authors.affiliation: Nicarnica Aviation AS, Vollsveien 9-11, N-1366, Lysaker, Norway.
authors.forename: D
authors.initials: D
authors.lastname: Moriano
authors.affiliation: Nicarnica Aviation AS, Vollsveien 9-11, N-1366, Lysaker, Norway.
authors.forename: C
authors.initials: C
authors.lastname: Bernardo
authors.affiliation: Department for Mechanical Engineering, Düsseldorf University of Applied Sciences, Düsseldorf, Germany.|Section for Meteorology and Oceanography, Department of Geoscience, University of Oslo, Norway.|Atmosphere and Climate Department, Norwegian Institute for Air Research, Kjeller, Norway.
authors.forename: A
authors.initials: A
authors.lastname: Vogel
authors.affiliation: Department of Earth Sciences, University of Oxford, UK.
authors.forename: G S
authors.initials: GS
authors.lastname: Prata
authors.affiliation: Department of Earth Sciences, University of Oxford, UK.
authors.forename: T A
authors.initials: TA
authors.lastname: Mather
authors.affiliation: Nicarnica Aviation AS, Vollsveien 9-11, N-1366, Lysaker, Norway.|Visiting Scientist, School of Earth Sciences, University of Bristol, BS8 1RJ.
authors.forename: H E
authors.initials: HE
authors.lastname: Thomas
authors.affiliation: AIRBUS SAS, Toulouse, France.
authors.forename: J
authors.initials: J
authors.lastname: Cammas
authors.affiliation: AIRBUS Operations SAS, Toulouse, France.
authors.forename: M
authors.initials: M
authors.lastname: Weber