Implementation and validation of a meteorological dispersion model applied on volcanic gas emission for studies of environmental impact

Abstract

The Lagrangian atmospheric transport model FLEXPART-WRF was implemented to model dispersion of volcanic gas emitted from the three volcanoes Popocatépetl in Mexico (lat: 19.02, lon: -98.62), Tungurahua in Ecuador (lat: -1.47, lon: -78.44) and Nyiragongo in D.R. Congo (lat: -1.52, lon: 29.25). Meteorological data from ECMWF with 1/8th degree spatial resolution and 6 hour temporal resolution was fed into the mesoscale meteorological model WRF (Advanced Research WRF 3.2.1) and run for three nested grids with 9, 3 and 1 km resolution with hourly outputs. This data was provided into FLEXPART-WRF, simulating emissions of 100 000 particles per day. The modelled concentration fields were used for producing sum of concentrations in slant and vertical columns which were compared to measurement data from scanning differential optical absorption spectroscopy (DOAS) instruments between 5 and 15 km from the volcanoes as well as car traverse measurements using mobile DOAS instruments. The model shows agreement with individual scans from the scanning instruments but the spread in the results of quantifiable parameters such as plume height and width is large. When comparing with the mobile measurements the model gives very good agreement in about two thirds of the cases. Finally, a simulation of ground dose over one month (December 2009) was also performed for Nyiragongo.