The role of in-situ measurements of volcanic ash concentrations in preventing economic disasters due to volcanic ash clouds

Abstract

During the Eyjafjallajökull eruption in 2010 and the Grimsvotn eruption in 2011, a lot of airports where closed because ash cloud predictions were much on the safe side compared to the actual ash clouds. This created a staggering economic disaster. An extent of predicted ash clouds, up to 40 times the size of the real clouds, are documented. Modern methods in disaster prevention can probably not eliminate airport closures altogether, but including in-situ airborne measurements of volcanic ash concentrations with OPC technology and other scientific methods of ash cloud assessment can reduce unnecessary airport closings to insignificant levels. Airborne measurements by a team of German, Icelandic and Japanese scientists have shown that important methods, additional to computer simulations by source models, are available. An example of parameter and ash volume predictions is shown, supported by measurements from Iceland, Germany and Japan. It is concluded, that point source diffusion models can only have a limited value in predicting scenarios of ash clouds, unless supported by in-situ observations of good quality.