The OMI/Aura Level-3e SO2 Data Product OMSO2e (Version 003) is now available from the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) for public access (http://disc.gsfc.nasa.gov/Aura/OMI/omso2e_v003.shtml)
       
The Ozone Monitoring Instrument (OMI) was launched aboard the EOS-Aura satellite on July 15, 2004 (1:38 pm equator crossing time, ascending mode). OMI, with its 2600 km viewing swath width, provides almost daily global coverage. OMI is a contribution of the Netherlands Space Office (NSO) in collaboration with the Finish Meterological Institute (FMI), to the US EOS-Aura Mission. The principal investigator is Dr. Pieternel Levelt of the KNMI (Royal Netherlands Meteorological Institute). OMI is designed to monitor stratospheric and tropospheric ozone, clouds, aerosols and smoke from biomass burning, SO2 from volcanic eruptions, and key tropospheric pollutants (HCHO, NO2) and ozone depleting gases (OClO and BrO). OMI sensor counts, calibrated and geolocated radiances, and all derived geophysical atmospheric products are archived at the NASA Goddard DAAC.
  
(The shortname for this Level-3 OMI total column SO2 product is OMSO2e) 
The  lead algorithm scientist for this product is NASA/GSFC OMI scientist Dr. Nikolay Krotkov (nickolay.a.krotkov@nasa.gov).

In this Level-3 daily global SO2 data product, each grid contains only one observation of Total Column Density of SO2 in the Planetary Boundary Layer (PBL,) based on an improved Band Residual Difference Algorithm (BRD). This single observation is the "best pixel", selected from all "good" L2 pixels of OMSO2 that overlap this grid and have UTC time betweeen UTC times of 00:00:00 and 23:59:59.9999. In addition to the SO2 Vertical column value some ancillary parameters e.g cloud fraction, terrain height, scene number, solar and satellite viewing angles, row anomaly flags, and quality flags have been also made available corresponding to the best selected SO2 data pixel in each grid.       
   
OMSO2e files are stored in EOS Hierarchical Data Format (HDF-EOS5). The maximum file size for the OMTO3e data product is about 7 Mbytes. A list of tools for browsing and extracting data from these files can be found from the site http://daac.gsfc.nasa.gov/Aura/tools.shtml 

A short OMSO2e Readme Document that includes a brief algorithm description and documents that provide known data quality related issues are available from the OMI GES DISC site( http://disc.sci.gsfc.nasa.gov/Aura/data-holdings/OMI/omso2e_v003.shtml )