BrO/SO2 studies at Mt. Etna during 2006 and 2007

In 2006 and 2007 during a series of different volcanic activities of Mt. Etna, including Lava flows strombolian explosions, Lava fountains, field studies, focusing on halogen oxides and sulphur dioxide emissions, were taking place with a scanning- as well as with a mobile-DOAS instrument. The Differential Optical Absorption Spectroscopy (DOAS) is an optical remote sensing technique and can simultaneously measure several trace gases. A BrO/SO2 time series from a fixed distance at 6 km from the emission source and gas emissions close to the different main craters and above lava flows were studied with the scanning DOAS instrument. In the same time period sulphur dioxide flux measurements were frequently carried out with a mobile-DOAS instrument at Mt. Etna during different states of volcanic activity. The SO2 fluxes varied between 194 t/d and 8800 t/d. The BrO/SO2 ratio showed peak three moth before the eruption started and the changes were not directly correlated to the changes in SO2 fluxes and therefore could provide additional information of the volcanic system. The BrO/SO2 ratio, a minimal bromine flux itself, which was calculated by using simultaneously measured SO2 fluxes, are presented in the context of the changing activity during the Mt. Etna 2006 eruption and the year 2007.