Application of the atmospheric Lagrangian particle dispersion model MLDP0 to the 2008 eruptions of Okmok and Kasatochi volcanoes

Abstract

The atmospheric transport and dispersion model Modle Lagrangien de Dispersion de Particules d'ordre zéro (MLDP0) has been in use at the Canadian Meteorological Centre (CMC) for several years. The model is employed to support environmental emergency response activities, in the context of CMC's national and international mandates. MLDP0 is a Lagrangian model in which diffusion is modeled according to a random displacement equation (RDE). MLDP0 is an off-line model and is driven with meteorological fields from CMC's Numerical Weather Analysis and Prediction (NWP) system. MLDP0 can be executed in forward and inverse modes. During the summer of 2008, the important eruptions at Okmok and Kasatochi, in the Aleutians, were cause of considerable concern to aviation, and the model was used extensively to support the Montreal Volcanic Ash Advisory Centre (VAAC). Qualitative comparisons of satellite imagery and MLDP0 outputs show that the model accurately simulated the behavior of volcanic plumes. Inverse simulations based on SO 2 observations of the Okmok plume, at the Washington State University campus in Pullman, Washington, yield emission estimates that agree well with those derived from AURA/OMI. Forward simulations using AURA/OMI SO 2 emission estimates for the Kasatochi eruption of 7 August also compare quite well quantitatively with observations from Environment Canada's Brewer spectrophotometers in Toronto, as well as with concentration maps reconstructed from AURA/OMI scans. Copyright 2010 by the American Geophysical Union.