Volcanic SO2 fluxes derived from satellite data: a survey using OMI, GOME-2, IASI and MODIS
- 1Belgian Institute for Space Aeronomy (BIRA-IASB), Brussels, Belgium
- 2Spectroscopie de l'Atmosphère, Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles (ULB), Brussels, Belgium
- 3Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy
- 4UPMC Univ. Paris 6, Université Versailles St.-Quentin, CNRS/INSU, LATMOS-IPSL, Paris, France
- 5Institut de Physique du Globe de Paris (IPGP), Paris, France
- *now at: Instituto de Geofisica, Universidad Nacional Autónoma de Mexico, Mexico City, Mexico
Abstract. Sulphur dioxide (SO2) fluxes of active degassing volcanoes are routinely measured with ground-based equipment to characterize and monitor volcanic activity. SO2 of unmonitored volcanoes or from explosive volcanic eruptions, can be measured with satellites. However, remote-sensing methods based on absorption spectroscopy generally provide integrated amounts of already dispersed plumes of SO2 and satellite derived flux estimates are rarely reported.
Here we review a number of different techniques to derive volcanic SO2 fluxes using satellite measurements of plumes of SO2 and investigate the temporal evolution of the total emissions of SO2 for three very different volcanic events in 2011: Puyehue-Cordón Caulle (Chile), Nyamulagira (DR Congo) and Nabro (Eritrea). High spectral resolution satellite instruments operating both in the ultraviolet-visible (OMI/Aura and GOME-2/MetOp-A) and thermal infrared (IASI/MetOp-A) spectral ranges, and multispectral satellite instruments operating in the thermal infrared (MODIS/Terra-Aqua) are used. We show that satellite data can provide fluxes with a sampling of a day or less (few hours in the best case). Generally the flux results from the different methods are consistent, and we discuss the advantages and weaknesses of each technique. Although the primary objective of this study is the calculation of SO2 fluxes, it also enables us to assess the consistency of the SO2 products from the different sensors used.