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V005 MODIS LST/Emissivity Daily 6km Quality Science Data Sets
The table below lists the bit field legend for the LST Quality Indicators. This information is excerpted from the file specifications for V005 MOD11B1 found at ftp://modular.nascom.nasa.gov/pub/LatestFilespecs/collection5/.
The QC science data sets in this product (QC_Day, QC_Night, and QC_Emis) provide the user with information on algorithm results that can be viewed in a spatial context for each pixel. The QC information tells if algorithm results were nominal, abnormal, or if other defined conditions were encountered for a pixel. The QC information should be used to help determine the usefulness of the LST data for a user's needs. The QC information can be extracted by reading the flags stored in an 8-bit unsigned integer. See Table 1 (QC_Day, QC_Night) and Table 2 (QC_Emis) below.
Table 1: LST Quality Indicators, Day and Night
NOTE: There is no FillValue for the QC SDS. This SDS should be used together with the LST SDS. If LST has FillValue 0, the 0-1 bits in QC have values of 10 or 11, other bit fields with 0 as undefined.
| Bit No. | Long Name | Bit Comb. | V005 MOD11B1 QC_DAY, QC_NIGHT |
|---|---|---|---|
| 0-1 | Mandatory QA Flags | 00 | LST produced, good quality, not necessary to examine more detailed QA |
| 01 | LST produced, other quality, recommend examination of more detailed QA | ||
| 10 | LST not produced due to cloud effects | ||
| 11 | LST not produced primarily due to reasons other than cloud | ||
| 2 | Data Quality Flag | 0 | Good data quality of L1B in 7 TIR bands |
| 1 | Other quality data | ||
| 3 | Terra/Aqua combined-use flag | 0 | No |
| 1 | Yes | ||
| 4-5 | Emis Error Flag | 00 | Average emissivity error <= 0.01 |
| 01 | Average emissivity error <= 0.02 | ||
| 10 | Average emissivity error <= 0.04 | ||
| 11 | Average emissivity error > 0.04 | ||
| 6-7 | LST Error Flag | 00 | Average LST error <= 1K |
| 01 | Average LST error <= 2K | ||
| 10 | Average LST error <= 3K | ||
| 11 | Average LST error > 3K |
Table 2: Emissivity Quality Indicators
NOTE: There is no FillValue for this SDS. It should be used together with LST_Day_6km or LST_Night_1km.
| Bit No. | Long Name | Bit Comb. | V005 MOD11B1 QC_Emis |
|---|---|---|---|
| 0-3 | View angle flag of the companion observation (which is night obs if LST_Day_6km valid, or day obs otherwise | 0 15 | Index of view angle sub-range of the companion observation |
| 0 7 | If view from East (0 at the west end of scan line) | ||
| 8 15 | If view from West (15 at east end of scan line) | ||
| 4 6 | Time difference between day and night MODIS observations | 0 7 | Couple of days, 7 representing the range from 7 to 16 |
| 7 | DEM slope flag | 0 | DEM slope not considered |
| 1 | DEM slope considered in day/night method |
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