OMI/Aura DOAS Total Column Ozone Zoomed 1-Orbit L2 Swath 13x12km V003 (OMDOAO3Z) at GES DISC

The reprocessed Aura Ozone Monitoring Instrument (OMI) Level-2 Zoomed Ozone data product OMDOAO3Z at 13x12 km resolution is now available from the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) for the public access. It is the second release of Version 003 and was reprocessed late 2011. OMI provides two sets of total column ozone products OMTO3 and OMDOAO3 which are based on two different algorithms. OMTO3 product is based on TOMS like ozone retrieval algorithm whereas OMDOAO3 total column ozone product is based on the Differential Absorption Spectroscopy (DOAS) fitting technique that essentially uses the OMI visible radiance values between 331.1 and 336.1 nm. The DOAS retrieval algorithm is developed by the KNMI OMI Scientist, Dr Pepijn Veefkind. Based on spatial resolutions, there are two DOAS algorithm based ozone products, OMDOAO3 (at 13x24 km resolution) and OMDOAO3Z (13x12 km resolution). In addition to the total ozone column values these DOAS based ozone products also contain some auxiliary derived and ancillary input parameters e.g. ozone slant column density, ozone ghost column density, air mass factor, scene reflectivity, radiance over the DOAS fit window, root mean square of DAOS fit, cloud fraction, cloud radiance, cloud pressure, terrain height, geolocation, viewing angles and quality flags. The shortname for this Level-2 OMI Zoomed Ozone product is OMDOAO3Z.

The OMDOAO3Z files are stored in the version 5 EOS Hierarchical Data Format (HDF-EOS5). Each file contains data from the day lit portion of an orbit (~53 minutes). OMDOAO3Z data files are based on Zoomed Level 1B radiance observations which are made once a month. Thus there is one day of zoomed data (approximately 14 orbits) per month. The maximum file size for the OMDOAO3Z data is approximately 30 MB.