The role of in-situ measurements in of volcanic ash concentrations in preventing economic disasters due to volcanic ash clouds.
During the Eyjafjallajökull eruption in 2010 and the Grimsvotn eruption in 2011 a lot of airports where closed unnecessarily because of ash cloud predictions too much on the „safe side“. 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 such unnecessary 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, other than computer simulations by source models, are available. An example of parameter and ash volume predictions is shown, supported by measurements from Iceland, Germany and Sakurajima in Japan. It is concluded, that point source diffusion models can only have a limited value in predicting scenarios of ash clouds, unless significantly supported by in-situ observations.
Volcanic ash; disaster prevention; in-situ observations; OPC measaurements; dispersion models