ESTIMATION OF THE SO2 FLUX OF THE ERUPTION PLUME OF THE MT. ETNA VOLCANO USING MIVIS AND ASTER DATA

In this paper two procedures to estimatethe SO2 flux emitted from Mt. Etna volcano areshortly described. These procedures are basedon the atmospheric simulations performed usingMODTRAN 3.5 radiative transfer code. Thefirst procedure, named LUT-procedure [seeTeggi et al. 1999], inverts the radiative transferequation minimizing the square differences ofthe experimental and simulated radiances at thesensor. The second procedure is based on theSplit-Window technique (i.e. it uses two bandswith different absorption characteristics). TheSplit-Window permits a direct (and fast) determinationof the SO2 columnar abundance of thevolcanic plume, but at least two of the four parametersof the algorithm depend on the state ofthe atmosphere (temperature and precipitablewater). Considering four years of radio soundingscarried out at midday at Trapani WMOstation, a seasonal trend of the above mentionedparameters have been obtained. The quoted procedureshave been applied to aircraft (MIVIS)and spacecraft (ASTER) remotely sensed imagesand the SO2 abundance maps have beenobtained; for ASTER data the shown results arequite preliminary. Knowing the wind speed atthe craters altitude the SO2 flux has been alsocomputed.