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

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 simu...

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Bibliographic Details
Published in:Atmospheric Chemistry and Physics
Main Authors: H. Vogel, J. Förstner, B. Vogel, T. Hanisch, B. Mühr, U. Schättler, T. Schad
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2014
Subjects:
Online Access:https://doi.org/10.5194/acp-14-7837-2014
https://doaj.org/article/d6cf1266feea4d67a24c924c8fc82147
Description
Summary: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.