Title: New perspectives on global SO2 emissions from the Ozone Monitoring Instrument (OMI)

Simon A. Carn, UMBC

The Ozone Monitoring Instrument (OMI) is an ultraviolet (UV) sensor launched on the EOS-Aura spacecraft in July 2004 with the primary task of mapping global ozone concentrations. OMI also offers unprecedented spatial and spectral resolution and global coverage for space-based UV measurements of sulfur dioxide (SO2), and will continue the long-term record of volcanic SO2 emissions derived from the Total Ozone Mapping Spectrometer (TOMS) instruments.
OMI is providing unique observations of SO2 in volcanic and polluted regions. Noise levels are at least five times lower than TOMS, allowing robust detection of lower tropospheric SO2. We are measuring passive degassing from several volcanoes on a daily basis. Explosive volcanic eruption clouds can be tracked for longer than was possible with TOMS, providing critical data for aviation hazard mitigation. Anthropogenic SO2 has been detected over eastern China, North and South America and Europe.
Using OMI data, we can now directly compare global SO2 emissions from anthropogenic and volcanic sources for the first time, and thus provide important new constraints on the relative magnitude of these fluxes. Such measurements are essential given the growing concern over the response of the Earth to anthropogenically-forced climate change and intercontinental transport of air pollution. A fast SO2 retrieval we have developed is also amenable to operational SO2 alarm development, and near real-time application for aviation hazards and volcanic eruption warnings.