The Eyjafjallajökull-Fimmvörduháls glacier ash cloud measurements will be a little more accurate, it seems.
The good news comes after DMI has analysed LIDAR measurements from Risø. At DMI, Chief Consultant Jens Havskov Sørensen has exchanged data with Torben Mikkelsen from Risoe National Laboratory for Sustainable Energy, the Technical University of Denmark, and compared the measurements from Risø's LIDAR with DMI's model cloud and cloud observations.
The conclusion is that DMI's model calculations are well in line with Risø's LIDAR observations.
What is a LIDAR?
Aerosol-LIDARs (LIght Detection And Ranging) are useful tools for measuring smoke plumes, cloud droplets and other particles in the atmosphere. The measurements can be conducted over time and across large areas.
The Aerosol-LIDAR shoots a laser beam up into the air where it hits particles and is reflected back to the LIDAR, providing information about particles in the atmosphere. LIDARs are, among other things, used to measure the height of the so-called boundary layer, i.e. to determine the altitude of any turbulence in the atmosphere, which has a considerable bearing on wind-turbine operations.
Moreover, Wind-LIDARs are used to calculate the instant speed and direction of the wind.
Torben Mikkelsen and his colleague from Risø DTU, Sven-Erik Gryning, have now started collaborating with international colleagues and with DMI on using the LIDAR to map the ash cloud:
"We have already entered into international collaboration with Leosphere in France, a manufacturer of LIDARs, and via their LEONET of connected LIDARs they will submit online measurements of the ash cloud to the international meteorological organisations such as UKMO in the UK and WMO (under the UN)," says Torben Mikkelsen.
"Grounding aircraft solely on the basis of model calculations is problematic because we know that models do not always totally agree with reality. By means of LIDARs sited around Europe, we can now carry out measurements and collect real-time data of the cloud in the atmosphere. This means that assessments will be more accurate and help improve the calculation models used by the meteorologists," says Torben Mikkelsen