WRF-Chem modeling of sulfur dioxide emissions from the 2008 Kasatochi Volcano

Abstract

We simulate the dispersion and chemical evolution of the sulfur dioxide (SO2) plume following the eruption of Kasatochi Volcano in Alaska, USA, on August 7th, 2008 with the Weather Research Forecasting with Chemistry (WRF-Chem) model. The model was initialized with the observed three distinct plumes, which were characterized by a total estimated SO2 mass of 0.5 to 2.7 Tg. WRF-Chem modeled output was compared to remote sensing retrievals from the Ozone Monitoring Instrument (OMI), and the modeled plumes agreed well in shape and location with the OMI retrievals. The calculated SO2 column densities showed comparable Dobson Unit values with higher densities especially in the center of the distal plume over northern Canada. We concluded from our analysis that WRF-Chem derived a 9.1-day lifetime of the SO2 when initialized with a 12km eruption height. Sensitivity tests with varying eruption plume heights revealed significantly in- creased lifetimes of SO2 up to 17.1 days for higher plumes.

Keywords

• WRF-Chem, volcano, sulfur dioxide, model, emissions