Satellite observations of atmospheric SO2 from volcanic eruptions during the time-period of 1996-2002

In this article, we present satellite observations of atmospheric sulfur dioxide (SO2) from volcanic eruptions. Global ozone monitoring experiment (GOME) data for the years 1996-2002 is analyzed using a DOAS based algorithm with the aim of retrieving SO2 slant column densities (SCD). The retrieval of SO2 SCD in the UV spectral region is difficult due to strong and interfering ozone absorptions. It is also likely affected by instrumental effects. We investigated these effects in detail to obviate systematic biases in the SO2 retrieval. A quantitative study of about 20 volcanoes from Italy, Iceland, Congo/Zaire, Ecuador, Japan, Vanuatu Island and Mexico is presented. The focus is on both eruption and out gassing scenarios. We prepared a 7-year mean map (1996-2002) of SO2 SCD observed by GOME and tabulated the ratios of the maximum SO2 SCD observed to the average SO2 SCD as seen in the 7-year mean map. The further aim of this study is to provide information about unknown volcanic eruptions, e.g., Bandai Honshu Japan, Central Islands Vanuatu, Piton de la Fournaise Réunion Island France, Kamchatka region of Russia and from Indonesia especially. The results demonstrate a high sensitivity of the GOME instrument towards SO2 emissions during both eruption and degassing episodes.