This Level-2G daily global gridded total columnozone product 'OMTO3G' is based on the pixel level OMILevel-2 Total Ozone product OMTO3. The OMTO3 product is based on enhanced TOMS version-8 algorithm that essentially uses the ultraviolet radiance data at 317.5 and 331.2 nm. OMI provides two total column ozone products OMTO3 and OMDOAO3 at the pixel resolution (13 x 24 km at nadir) that are based on two different algorithms.
OMTO3G data product is a special Level-2 gridded product where pixel level products are binned into 0.25x0.25 degree global grids. It contains the data for all L2 "scenes" that have observation time betweeen UTC times of 00:00:00 and 23:59:59.9999. All data pixels that fall in a grid box are saved without averaging. Scientist can apply data filtering scheme of their choice and create new gridded products. The GES DISC developed interactive tool 'Giovanni' provides web based capabilites to browse and explore these data.
The OMTO3G data productcontains almost all parameters that are contained in OMTO3. For example, in addition to the total column ozone it also contains effective Lambertian scene-reflectivity, UV aerosol index, SO2 index, cloud fraction, cloud pressure, ozone below clouds, terrain height, geolocation, solar and satellite viewing angles, and extensive quality flags.
The shortname for this Level-2 G OMI total column ozone product is OMTO3G and thealgorithm lead for the original OMTO3 and OMTO3G product is NASA OMI scientist Dr. Pawan K. Bhartia ( Pawan.K.Bhartia@nasa.gov).
OMTO3G files are stored in EOS Hierarchical Data Format (HDF-EOS5). Each file contains daily data fromapproximately 14 orbits . The maximum file size for the OMTO3G data product is about 150 Mbytes.
A list of tools for browsing and extracting data from these files can be found at:
For the on-line visualization services ( Giovanni), please visit the site
OMTO3 Readme Document that includes brief algorithm description and data quality issues and the document containing Known Issues have been provided by the OMTO3 Algorithm lead. OMTO3 data is used in producing OMTO3G product. OMTO3G File Spec is also available.
For more information on Ozone Monitoring Instrument and atmospheric data products, please visit the OMI-Aura sites:
Contacts for Data Access Information:
GES DISC DAAC Help Desk
Data Center Identification:
GSFC-ECS - Goddard Space Flight Center Distributed Active Archive Center, NASA
Ahmad, S. P., P. F. Levelt, P. K. Bhartia, E. Hilsenrath, G. W. Leppelmeier, and J. E. Johnson, "Atmospheric Products from the Ozone Monitoring Instrument (OMI)", Proceedings of SPIE conference on Earth Observing Systems VIII, San Diego, California, Aug 3-8, 2003. [Full-Text]
P. K. Bhartia and C. W. Wellemeyer, "OMI TOMS-V8 Total O3 Algorithm,"Algorithm Theoretical Baseline Document: OMI Ozone Products, P. K. Bhartia (ed.), vol. II, ATBD-OMI-02, version 2.0, Aug. 2002.
Brinksma, E. J., K. F. Boersma, and P. F. Levelt, OMI-Validation Requirements, May 16, 2003.
Froidevaux, L. and A. Douglass, Earth Observing System (EOS) Aura Science Data Validation Plan, July 2001
Levelt, P.F., J. P. Veefkind, R. H. M. Voors, and J. de Vries, "Instrument Description", Algorithm Theoretical Baseline Document: OMI Instrument, Level 0 - 1B processor, Calibration & Operations, P. F. Levelt (ed.), vol. I, ATBD-OMI-01, version 2, Aug. 2002.
Levelt, P. F., B. van den Oord, E. Hilsenrath, G. W. Leppelmeier, P. K. Bhartia, A. Malkki, H. Kelder, R. J. van der A, E. J. Brinksma, R. van Oss, P. Veefkind, M. van Weele, and R. Noordhoek, "Science Objectives of EOS-Aura's Ozone Monitoring Instrument (OMI)", Proc. Quad. Ozone Symposium, Sapporo, Japan, pp. 127-128, 2000.
Schoeberl, M.R., A.R. Douglass, E. Hilsenrath, P.K. Bhartia, J. Barnett, J. Gille, R. Beer, M. Gunson, J. Waters, P.F. Levelt, P. DeCola, "The EOS Aura Mission," EOS, Transactions, American Geophysical Union 85 , Number 18, 4 May 2004. [ Preprint]
Document Revision Date:
Last modified: Monday May 2 10:38:04 EDT 2005
Document Review Date:April 20, 2005
Document Curator: Dr. Suraiya P. Ahmad