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OMI L2G Data Filtering and Masking Options

Science Team Recommended Values

Filtering Variables ParametersMinMax
Scene Number
(Row Anomaly)
allvaries (see table below for details)
Viewing Zenith Angleall070
Solar Zenith AngleColumn Amount Ozone &
Radiative Cloud Fraction (OMTO3G)
084

Aerosol Absorption Optical Depth,

Aerosol Extinction Optical Depth,

Aerosol Single Scattering Albedo &

Reflectivity (OMAERUVG);

Aerosol Optical Thickness & Sngle Scattering Albedo (OMAEROG);

UV Aerosol Index (OMTO3G);

SO2 Column Amount TRM &

Radiative Cloud Fraction (OMSO2G)

070
Radiative Cloud Fraction

Column Amount Ozone, Rative Cloud Fraction & Aerosol Index (OMTO3G);

SO2 Column Amount TRM &

Radiative Cloud Fraction (OMSO2G)

0.01.0
Path Length Index Column Amount Ozone &
Radiative Cloud Fraction (OMTO3G)
314

Aerosol Absorption Optical Depth,

Aerosol Extinction Optical Depth,

Aerosol Single Scattering Albedo &

Reflectivity (OMAERUVG);

Aerosol Optical Thickness & Sngle Scattering Albedo (OMAEROG);

UV Aerosol Index (OMTO3G);

SO2 Column Amount TRM &

Radiative Cloud Fraction (OMSO2G)

37
Ocean Glint Angle Column Amount Ozone (OMTO3G),
Radiative Cloud Fraction (OMTO3G),
0-
UV Aerosol Index (OMTO3G)+/-20-


Scene Number / Row Anomaly Screening

The pixel scene or row number in the cross-track direction (1 - 60).

Start TimeEnd TimeStart RowEnd Row
2007-06-25 5455
2008-05-112008-12-033843
2008-12-032009-01-243845
2009-01-242009-02-022845
2009-02-022009-03-032946
2009-03-032009-03-302947
2009-03-302009-04-212948
2009-04-212009-05-062951
2009-05-062009-05-182952
2009-05-182009-08-182953
2009-08-18 2653

Viewing Zenith Angle
The angle between the local zenith and the line of sight to the spacecraft.

Solar Zenith Angle
The angle between the local zenith and the line of sight to the sun.

Radiative Cloud Fraction
Provides the ability to filter clear sky (i.e. < 30%) versus cloudy scenes.

Path Length Index
The path length index gives an indication of the best viewing condition, giving more importance to the viewing zenith angle than on solar zenith angle, particularly at higher latitudes where solar zenith angles are large. The path length index is defined as

1/cos(SZA) + 2/cos(VZA).

where SZA = solar zenith angle, and VZA = viewing zenith angle

Ocean Glint Width Angle
The ocean glint width angle is twice the scattering angle over water when the Sun is near overhead. The scattering angle is defined as

cos-1 ( cos(SZA)*cos(VZA) + sin(SZA)*sin(VZA)*cos(RAA) )

where SZA = solar zenith angle, VZA = viewing zenith angle, and RAA = relative azimuth angle.

Please NOTE: data are also screened to excludethe solar eclipse flag set (in the GroundPixelQualityFlags field). Data from descending portion of orbit are excluded.

 

OMTO3G:

Ozone and Radiative Cloud Fraction: only data values where the QualityFlags is 0 or 1 are included

UV Aerosol Index: only data values where the QualityFlags is less than 6 are included.

 

OMSO2G:

The values have been screened so only data where the QualityFlags bit 0 is not set (i.e. good data) are used; scenes 38 - 41 above 60 deg are removed from May 11, 2008.


 Al
You may also obtain the original Level 2G (unfiltered) data.

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Last updated: Apr 06, 2016 04:17 PM ET
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