This dataset contains (ENS01) the output of the prior ensemble, consisting of 1000 volcanic ash transport and dispersion model (Numerical Atmospheric-dispersion Modelling Environment - NAME) simulations of the 2019 Raikoke eruption. (ENS03 and 08) the output of two posterior ensembles of volcanic ash transport and dispersion model simulations used for comparison to satellite retrievals and the prior ensemble. The datasets were used to produce probability, concentrations and concentration risk maps. The use of this data is outlined in Antonio Capponi et al. (2021): Refining an ensemble of volcanic ash forecasts using satellite retrievals: Raikoke 2019