A Fast Algorithm for Retrieval of Volcanic Sulfur Dioxide With OMI

The Ozone Monitoring Instrument (OMI) on EOS/Aura provides daily global measurements of volcanic sulfur dioxide (SO2) emissions. Its high spatial and hyper-spectral resolutions have enabled detection of much smaller amount of atmospheric SO2 than its predecessors such as the Global Ozone Monitoring Experiment (GOME) and the Total Ozone Mapping Spectrometer (TOMS), and with daily, contiguous coverage that is not achievable with Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY). A fast algorithm, called the linear fit algorithm, has been developed for retrieval of volcanic SO2 for public release. This algorithm uses the calibrated residuals centered at 12 wavelengths produced by the NASA operational ozone algorithm (OMTO3), to derive SO2, O3, and effective surface reflectivity simultaneously. This fast SO2 retrieval is suitable to operational SO2 alarm development, and near real-time application for aviation hazards and volcanic eruption warnings. We will describe the algorithm and present sample results, from detecting volcanic degassing in the boundary layer and lower troposphere to tracking stratospheric volcanic clouds over an extended period of time.