Estimating the total mass emitted by the eruption of Eyjafjallajökull in 2010 using plume-rise models

• Source mass flux determined for total duration of 2010 Eyjafjallajökull eruption
• Good agreement with observations
• Quantify sensitivity to changes in the entrainment coefficients
• Show how sensitivity to crosswind entrainment coefficient can be reduced

The volcanic plume-rise model of Devenish (2013) is applied to the duration of the 39-day eruption of Eyjafjallajökull in 2010 to produce a time series of the estimated source mass flux. This in turn is integrated to give the total emitted mass, which is found to lie within the error bounds of an observational estimate made by Gudmundsson et al. (2012). The calculation uses realistic profiles of key atmospheric variables such as wind speed, temperature, and humidity taken from a numerical weather prediction model and appropriate to the time of the eruption. The sensitivity of the model results to changes in the values of the entrainment coefficients is discussed. It is shown that including the radius of the plume (when it is strongly affected by the wind) in the comparison of the modelled and observed rise heights not only improves the accuracy of the estimated total emitted mass (compared with neglecting the radius) but also reduces the sensitivity of this estimate to the value of the entrainment coefficient associated with velocity differences normal to the plume axis.