Articles | Volume 14, issue 15
Atmos. Chem. Phys., 14, 7837–7845, 2014

Special issue: Atmospheric implications of the volcanic eruptions of Eyjafjallajökull,...

Atmos. Chem. Phys., 14, 7837–7845, 2014

Research article 07 Aug 2014

Research article | 07 Aug 2014

Time-lagged ensemble simulations of the dispersion of the Eyjafjallajökull plume over Europe with COSMO-ART

H. Vogel1, J. Förstner2, B. Vogel1, T. Hanisch2, B. Mühr1, U. Schättler2, and T. Schad1 H. Vogel et al.
  • 1Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology (KIT), Herrmann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
  • 2Deutscher Wetterdienst (DWD), Frankfurter Straße 135, 63067 Offenbach, Germany

Abstract. An extended version of the German operational weather forecast model was used to simulate the ash dispersion during the eruption of the Eyjafjallajökull. As an operational forecast was launched every 6 hours, a time-lagged ensemble was obtained. Sensitivity runs show the ability of the model to simulate thin ash layers when an increased vertical resolution is used. Calibration of the model results with measured data allows for a quantitative forecast of the ash concentration. After this calibration an independent comparison of the simulated number concentration of 3 μm particles and observations at Hohenpeißenberg gives a correlation coefficient of 0.79. However, this agreement could only be reached after additional modifications of the emissions. Based on the time lagged ensemble the conditional probability of violation of a certain threshold is calculated. Improving the ensemble technique used in our study such probabilities could become valuable information for the forecasters advising the organizations responsible for the closing of the airspace.

Final-revised paper