Dispersion modelling of the Kilauea plume

Emissions from the Kilauea volcano pose significant environmental and health risks to the Hawaiian community. This paper describes progress toward simulating the concentration and dispersion of plumes of volcanic aerosol after they emanate from the Pu'u O'o vent of the Kilauea volcano. In order to produce an accurate regional forecast of the concentration and dispersion of volcanic aerosol, the Hybrid Single-Particle Lagrangian Integrated Trajectory (HY-SPLIT) model was used. Wind fields and thermodynamic data from the non-hydrostatic Mesoscale Spectral Model (MSM) were employed as input for the HY-SPLIT model. A combination of satellite remote sensing, aircraft, and ground-based observations collected during a field experiment was used to validate the model simulation of aerosol distribution. The HY-SPLIT model shows skill in reproducing the plume shape, orientation, and concentration gradients as deduced from satellite images of aerosol optical depth. Comparison of the modelled and observed values suggests that the model was able to produce reasonable plume concentrations and spatial gradients downwind of the source. Model concentrations were generally less than those observed on the leeward side of the Island of Hawaii. This deficiency may be explained by a lack of (i) background concentrations, (ii) local sources of pollution and/or (iii) sea-breeze circulation in the prognostic input wind field. These results represent early progress toward the goal of future operational application of the HY-SPLIT model to predict volcanic aerosol concentrations in Hawaii. This may help mitigate their negative impacts of plumes respiratory health, agriculture, and general aviation.