Airborne Measurements of Volcanic Ash and Current State of Ash Cloud Prediction

Abstract

Eyjafjallajökull 2010 and Grímsvötn 2011 eruptions created great problems for commercial aviation in the North Atlantic because of the large extent of the predicted ash clouds from these eruptions. Comparison to satellite pictures showed the predictions very much larger than the ash cloud. Measurements also showed lower ash concentrations over Europe than the predicted. Papers on simulation of the Eyjafjallajökull Ash cloud in peer reviewed journals, usually tried to simulate the VAAC predictions rather than the satellite pictures, an example is shown. In the newest eruption in Iceland (Holuhraun – Bardarbunga) mostly SO2 was produced but if its output had been ash, it could have produced similar problems for the aviation as Eyjafjallajökull did. The plume was successfully modeled using the WRF-chem model. Kyoto Universities measurements and research of eruptions in Sakurajima has shown weak points in the diffusion theory used for ash cloud prediction of tropospheric plumes that tend to ride in stable temperature inversions