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Description

The reprocessed Aura Ozone Monitoring Instrument (OMI) Level-2 zoomed cloud data product OMCLDO2Z 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 cloud products based on two different algorithms, the Rotational Raman Scattering method and O2-O2 absorption method using the DOAS technique. This level-2 zoomed cloud product at the pixel resolution (13x12 km2 at nadir) is based on the spectral fitting of O2-O2 absorption band at 477 nm using DOAS technique. This product contains effective cloud pressure, effective cloud fraction, slant column O2-O2; uncertainties in derived, parameters, terrain and geolocation information, solar and satellite viewing angles, and quality flags. The shortname for this Level-2 OMI Zoomed cloud product is OMCLDO2Z. The lead scientist for this product is Dr. Pepijn Veefkind.

The OMCLDO2Z files are stored in the version 5 Hierarchical Data Format (HDF-EOS5). Each file contains data from the day lit portion of an orbit (~53 minutes) and is roughly 20 MB in size. OMCLDO2Z data files are based on Zoomed Level 1B radiance observations which are made once a month. Thus there is one zoomed cloud product per month.

Product Summary

Platforms
Aura
Instruments
OMI
Spatial Extent

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

Geographic Region
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
GEODETIC
Temporal Extent
2004-10-06 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
C1239966773-GES_DISC
Data State
ACTIVE
Number of Files/Granules
2640
Processing Level
2
Published
Updated
Science Keywords
Cloud Fraction ,
Cloud Top Pressure

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

Veefkind, P. (2012). OMI/Aura Cloud Pressure and Fraction (O2-O2 Absorption) Zoomed 1-Orbit L2 Swath 13x12km [Data set]. NASA Goddard Earth Sciences Data and Information Services Center. https://doi.org/10.5067/AURA/OMI/DATA2009 Date Accessed: 2025-12-14

Documents

READ-ME

PI DOCUMENTATION

ALGORITHM THEORETICAL BASIS DOCUMENT (ATBD)

GENERAL DOCUMENTATION

Variables

Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.

The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/ChiSquaredOfFit Chi-squared diagnostics of DOAS fit NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/CloudFraction Effective cloud fraction clipped between 0.0 and 1.0 NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/CloudFractionNotClipped Effective cloud fraction. NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/CloudFractionPrecision Precision of the effective cloud fraction NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/CloudPressure Effective cloud pressure clipped to the surface pressure hPa int16 -32768 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/CloudPressureNotClipped Effective cloud pressure, can be higher than the surface pressure hPa int16 -32768 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/CloudPressurePrecision Precision of the effective cloud pressure hPa int16 -32768 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/ContinuumAtReferenceWavelength Continuum reflectance at reference wavelength NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/ContinuumAtReferenceWavelengthPrecision Precision of the continuum reflectance at reference wavelength NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/InstrumentConfigurationId Unique ID for instrument settings for current measurement NoUnits uint8 255 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/MeanSunNormalizedRadiance Mean Sun Normalized Radiance over the DOAS Fit Window NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/MeasurementQualityFlags Bit level quality flags at measurement level NoUnits uint8 255 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/NumberOfSmallPixelColumnsUV Number of small pixels for current measurement of the UV channel NoUnits int8 -128 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/NumberOfSmallPixelColumnsVIS Number of small pixels for current measurement of the VIS channel NoUnits int8 -128 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/NumberOfWavelengthsInFit Number of wavelengths used in the spectral fit m int16 -32768 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/ProcessingQualityFlags Bit level quality flags at ground pixel level NoUnits uint16 65535 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/RingCoefficient Fitted ring coefficient molecule cm^-2 float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/RingCoefficientPrecision Precision of the fitted ring coefficient molecule cm^-2 float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/RootMeanSquareErrorOfFit Root-mean-square error of DOAS fit NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SceneAlbedo Retrieved albedo when the scene is represented by a Lambertian surface NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SceneAlbedoPrecision Precision of the scene albedo NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/ScenePressure Retrieved surface pressure when the scene is represented by a Lambertian surface hPa float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/ScenePressurePrecision Precision of the scene pressure hPa float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SlantColumnAmountNO2 NO2 slant column density molec/cm^2 float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SlantColumnAmountNO2Precision Precision of the NO2 slant column density molec/cm^2 float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SlantColumnAmountO2O2 O2-O2 slant column density molecule^2 cm^-5 float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SlantColumnAmountO2O2CorrectionFactor Slant Column Amount O2O2 temperature correction factor NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SlantColumnAmountO2O2Precision Precision of the O2-O2 slant column density molecule^2 cm^-5 float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SlantColumnAmountO3 Ozone slant column density DU float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SlantColumnAmountO3Precision Precision of the ozone slant column density DU float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SmallPixelMeanUV Mean radiance of the small pixels for wich the variance was computed. NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SmallPixelMeanVIS Mean radiance of the small pixels for wich the variance was computed. NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SmallPixelRadianceUV Radiance of small pixel data column of the UV channel photons/(s.nm.cm^2.sr) float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SmallPixelRadianceVIS Radiance of small pixel data column of the VIS channel photons/(s.nm.cm^2.sr) float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SmallPixelVarianceUV Relative variance of the radiance of the small pixel data of the UV channel NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SmallPixelVarianceVIS Relative variance of the radiance of the small pixel data of the VIS channel NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SmallPixelWavelengthUV Wavelength of small pixel column of the UV channel nm uint16 65535 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SmallPixelWavelengthVIS Wavelength of small pixel column of the VIS channel nm uint16 65535 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/SnowIceExtent Snow Ice extent information. Uses the NISE convention. NoUnits uint8 254 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/TerrainPressure Pressure of the center of the ground pixel hPa int16 -32768 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/TerrainReflectivity Reflectivity of the ground pixel NoUnits int8 -128 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/WavelengthRegistrationCheck Wavelength registration check of the L1B wavelength assignment based on the position of Fraunhofer absorption lines. This registration check can be applied as a correction, depending on an OPF parameter. See OPF_wavelengthRegistrationShiftRadianceGrid in the file attributes. nm float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/WavelengthRegistrationCheckStd Precision of the wavelength registration nm float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Data Fields/XTrackQualityFlags Across Track Quality Flags NoUnits uint8 255 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Geolocation Fields/GroundPixelQualityFlags Ground Pixel Quality Flags NoUnits uint16 65535 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Geolocation Fields/Latitude Latitude of the center of the groundpixel deg float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Geolocation Fields/Longitude Longitude of the center of the groundpixel deg float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Geolocation Fields/OrbitPhase The place of OMI in orbit NoUnits float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Geolocation Fields/SolarAzimuthAngle Solar azimuth angle at WGS84 ellipsoid for center co-ordinate of the ground pixel, defined East-of-North deg float32 -1.2676506002282E+30 N/A N/A
HDFEOS/SWATHS/CloudFractionAndPressure (60x557x4)/Geolocation Fields/SolarZenithAngle Solar zenith angle at WGS84 ellipsoid for center co-ordinate of the ground pixel deg float32 -1.2676506002282E+30 N/A N/A
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