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Description

This Level-2G daily global gridded product OMTO3G is based on the pixel level OMI Level-2 Total Ozone Product OMTO3. The OMTO3 product is from the enhanced TOMS version-8 algorithm that essentially uses the ultraviolet radiance data at 317.5 and 331.2 nm. The OMTO3G data product is a special Level-2 Global Gridded Product where pixel level data are binned into 0.25x0.25 degree global grids. It contains the data for all L2 scenes that have observation time for the 24-hour period beginning at 00:00:00 UTC. All data pixels that fall in a grid box are saved without averaging. Scientists can apply a data filtering scheme of their choice and create new gridded products.

The OMTO3G data product contains almost all parameters that are contained in the OMTO3. For example, in addition to the total column ozone it also contains cloud fraction, cloud pressure, terrain height, geolocation, solar and satellite viewing angles, and quality flags.

The OMTO3G files are stored in the version 5 EOS Hierarchical Data Format (HDF-EOS5). Each file contains daily data from approximately 15 orbits. The maximum file size for the OMTO3G data product is about 150 Mbytes.

Product Summary

Platforms
Aura
Instruments
OMI
Spatial Extent

N: 90 S: -90 E: 180 W: -180

Location
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2004-10-01 to Present
Data Partner
Goddard Earth Sciences Data and Information Services Center (formerly Goddard DAAC), Terrestrial Information Systems Laboratory, Earth Sciences Division, Science and Exploration Directorate, Goddard Space Flight Center, NASA (NASA/GSFC/SED/ESD/TISL/GESDI
Concept ID
C3377057175-GES_DISC
Data State
ACTIVE
Number of Files/Granules
7762
Processing Level
2G
Published
Updated
Science Keywords
Atmospheric Ozone ,
Reflectance ,
Aerosol Optical Depth/Thickness

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

Bhartia, P. K. (2025). OMI/Aura Ozone (O3) Total Column Daily L2 Global 0.25 deg Lat/Lon Grid [Data set]. NASA Goddard Earth Sciences Data and Information Services Center. https://doi.org/10.5067/AURA/OMI/DATA2425 Date Accessed: 2026-02-16

Documents

READ-ME

PI DOCUMENTATION

ALGORITHM THEORETICAL BASIS DOCUMENT (ATBD)

Variables

The table below lists the variables contained within a single granule for this dataset. Variables often contain observed or derived geophysical measurements collected from a variety of sources, including remote sensing instruments on satellite and airborne platforms, field campaigns, in situ measurements, and model outputs. The terms variable, parameter, scientific data set, layer, and band have been used across NASA’s Earth science disciplines; however, variable is the designated nomenclature in NASA’s Common Metadata Repository (CMR). Variable metadata attributes such as Name, Description, Units, Data Type, Fill Value, Valid Range, and Scale Factor allow users to efficiently process and analyze the data. The full range of attributes may not be applicable to all variables. Additional information on variable attributes is typically available in the data, user guide, and/or other product documentation.

For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/AlgorithmFlags Algorithm Flags NoUnits uint8 255 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/APrioriLayerO3 A Priori Ozone Profile DU float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/CloudPressure Effective Cloud Pressure hPa float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/ColumnAmountO3 Best Total Ozone Solution DU float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/GroundPixelQualityFlags Ground Pixel Quality Flags NoUnits uint16 65535 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/InstrumentConfigurationId Instrument Configuration ID NoUnits uint8 255 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/LandWaterClassification Land / Water Classification NoUnits uint8 255 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/Latitude Geodetic Latitude deg float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/LayerEfficiency Algorithmic Layer Efficiency NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/LineNumber Line Number of Candidate Scene NoUnits int32 -2000000000 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/Longitude Geodetic Longitude deg float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/MeasurementQualityFlags Measurement Quality Flags NoUnits uint8 255 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/NumberOfCandidateScenes Number of Candidate Scenes NoUnits int32 0 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/NumberSmallPixelColumns Number of Small Pixel Columns NoUnits uint8 255 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/O3BelowCloud Ozone Below Fractional Cloud DU float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/OrbitNumber Orbit Number of Candidate Scene NoUnits int32 -2000000000 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/PathLength Path Length NoUnits float32 1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/QualityFlags Quality Flags NoUnits uint16 65535 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/RadiativeCloudFraction Radiative Cloud Fraction = fc*Ic331/Im331 NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/Reflectivity331 Effective Surface Reflectivity at 331 nm % float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/Reflectivity360 Effective Surface Reflectivity at 360 nm % float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/RelativeAzimuthAngle Relative Azimuth Angle (sun + 180 - view) deg(EastofNorth) float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/Residual N-Value Residual NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/SceneNumber Scene Number of Candidate Scene NoUnits int32 -2000000000 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/SecondsInDay Seconds after UTC midnight s float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/SmallPixelColumn Small Pixel Column NoUnits int16 -32767 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/SO2index SO2 Index NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/SolarZenithAngle Solar Zenith Angle deg float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/StepTwoO3 Step 2 Ozone Solution DU float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/TerrainHeight Terrain Height m int16 -32767 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/TerrainPressure Terrain Pressure hPa float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/Time Time at Start of Scan (TAI93) s float64 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/UVAerosolIndex UV Aerosol Index NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/ViewingZenithAngle Viewing Zenith Angle deg float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/WaterFraction Percent Water Fraction % uint8 255 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/Wavelength Wavelength nm float32 -1.2676506002282E+30 N/A N/A
HDFEOS/GRIDS/OMI Column Amount O3/Data Fields/XTrackQualityFlags Cross Track Quality Flags NoUnits uint8 255 N/A N/A
HDFEOS INFORMATION/ArchivedMetadata HDFEOS INFORMATION/ArchivedMetadata N/A OTHER N/A N/A N/A
HDFEOS INFORMATION/CoreMetadata HDFEOS INFORMATION/CoreMetadata N/A OTHER N/A N/A N/A
HDFEOS INFORMATION/StructMetadata.0 HDFEOS INFORMATION/StructMetadata.0 N/A OTHER N/A N/A N/A
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