SO₂ satellite measurements

Sulfur dioxide measurements from satellites make it possible to monitor volcanic activity and eruptions on a global scale. The GOME-2 instrument on satellite MetOp-A provides SO₂ columns with a global coverage within 1.5 days with a spatial resolution of 40 x 80 km and makes it possible to detect and track volcanic SO₂ in near real time. GOME-2 is a spectrometer with continuous spectral coverage of the wavelength between 240 nm and 790 nm and a spectral resolution between 0.25 nm and 0.5 nm.

The volcanic SO₂ emissions are determined from solar backscatter measurements in the ultra-violet spectral range around 320 nm, applying the Differential Optical Absorption Spectroscopy (DOAS). This retrieval technique uses the high spectral resolution of the instrument to determine the total column density of SO₂. Near-real time GOME-2 SO₂ measurements and ground-based observations will be combined with a state-of-art particle-dispersion model and global meteorological models to monitor and forecast the dispersion of volcanic plumes up to 3 days and to attribute the detected SO₂ to a particular volcano. The main goal is to develop a volcanic monitoring and warning service using GOME-2 SO₂ data.

Goals and Workplan

• Daily information on active volcanoes based on GOME-2 SO₂ columns and trajectory matching
• Daily maps of GOME-2 SO₂ columns for the Azores test region and the other volcanic regions in Europe (Iceland and Italy/Greece)
• Daily maps of GOME-2 SO₂ columns for selected volcanic regions outside of Europe
• Related supplementary satellite imagery from Meteosat-8, AVHRR and MODIS
• SO₂ emission estimates based on GOME-2 measurements for the selected volcanic regions
• Validation results for the GOME-2 columns and emission estimates

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