Satellite Monitoring of Volcanic Sulfur Dioxide Emissions for Early Warning of Volcanic Hazards. - Meike Rix; Pieter Valks; Nan Hao; Jos van Geffen; Catherine Clerbaux; Lieven Clarisse; Pierre-François Coheur; Diego G. Loyola; Thilo Erbertseder; Walter Zimmer; Sunil Emmadi (IEEE J. Sel. Top. Appl. Earth Obs. Remote. Sens., 2009)