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V005 MODIS 8-Day Surface Reflectance 500m QA Science Data Sets
The QA information below is excerpted from an HDF-EOS file of the MODIS Surface Reflectance product MOD09A1.
The MOD09A1 product includes two QA layers, one relating band specific quality (Table 1), and the other presenting the surface reflectance state (Table 2).
Table 1: MOD09A1.005 500-meter Surface Reflectance Data QA Descriptions (32-bit)
| Bit No. | Parameter Name | Bit Comb. | Sur_refl_qc_500m |
|---|---|---|---|
| 31 | adjacency correction performed | 1 | yes |
| 0 | no | ||
| 30 | atmospheric correction performed | 1 | yes |
| 0 | no | ||
| 26-29 | band 7 data quality four bit range | 0000 | highest quality |
| 1000 | dead detector; data interpolated in L1B | ||
| 1001 | solar zenith >= 86 degrees | ||
| 1010 | solar zenith >= 85 and < 86 degrees | ||
| 1011 | missing input | ||
| 1100 | internal constant used in place of climatological data for at least one atmospheric constant | ||
| 1101 | correction out of bounds pixel constrained to extreme allowable value | ||
| 1110 | L1B data faulty | ||
| 1111 | not processed due to deep ocean or clouds | ||
| 22-25 | band 6 data quality four bit range | SAME AS BAND ABOVE | |
| 18-21 | band 5 data quality four bit range | SAME AS BAND ABOVE | |
| 14-17 | band 4 data quality four bit range | SAME AS BAND ABOVE | |
| 10-13 | band 3 data quality four bit range | SAME AS BAND ABOVE | |
| 6-9 | band 2 data quality four bit range | SAME AS BAND ABOVE | |
| 2-5 | band 1 data quality four bit range | SAME AS BAND ABOVE | |
| 0-1 | MODLAND QA bits | 00 | corrected product produced at ideal quality all bands |
| 01 | corrected product produced at less than ideal quality some or all bands | ||
| 10 | corrected product not produced due to cloud effects all bands | ||
| 11 | corrected product not produced due to other reasons some or all bands may be fill value [Note that a value of (11) overrides a value of (01)]. |
Table 2: MOD09A1.005 500-meter Surface Reflectance Data State QA Descriptions (16-bit)
| Bit No. | Parameter Name | Bit Comb. | Sur_refl_state_500m |
|---|---|---|---|
| 15 | internal snow algorithm flag | 1 | yes |
| 0 | no | ||
| 14 | BRDF correction performed | 1 | yes |
| 0 | no | ||
| 13 | Pixel is adjacent to cloud | 1 | yes |
| 0 | no | ||
| 12 | MOD35 snow/ice flag | 1 | yes |
| 0 | no | ||
| 11 | internal fire algorithm flag | 1 | fire |
| 0 | no fire | ||
| 10 | internal cloud algorithm flag | 1 | cloud |
| 0 | no cloud | ||
| 8-9 | cirrus detected | 00 | none |
| 01 | small | ||
| 10 | average | ||
| 11 | high | ||
| 6-7 | aerosol quantity | 00 | climatology |
| 01 | low | ||
| 10 | average | ||
| 11 | high | ||
| 3-5 | land/water flag | 000 | shallow ocean |
| 001 | land | ||
| 010 | ocean coastlines and lake shorelines | ||
| 011 | shallow inland water | ||
| 100 | ephemeral water | ||
| 101 | deep inland water | ||
| 110 | continental/moderate ocean | ||
| 111 | deep ocean | ||
| 2 | cloud shadow | 1 | yes |
| 0 | no | ||
| 0-1 | MOD35 cloud | 00 | clear |
| 01 | cloudy | ||
| 10 | mixed | ||
| 11 | not set, assumed clear |
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