## DESCRIPTION

i.modis.qc Extracts Requested Quality Assessment flags from the following MODIS products: MOD09A1, MOD09Q1, MOD11A1, MOD11A2, MOD13A2, MCD43B2. This does include MOD09A1 QA_state_500m layer (see Notes).

    MOD09A1/Q1: MODLAND QA Bits. bits=[0-1]

- [00]= class 0: Corrected product produced at ideal quality -- all bands
- [01]= class 1: Corrected product produced at less than ideal quality -- some or all bands
- [10]= class 2: Corrected product NOT produced due to cloud effect -- all bands
- [11]= class 3: Corrected product NOT produced due to other reasons -- some or all bands maybe be fill value (Note that a value of [11] overrides a value of [01])

    MOD09Q1: Cloud State. bits=[2-3]

- [00]= class 0: Clear -- No clouds
- [01]= class 1: Cloudy
- [10]= class 2: Mixed
- [11]= class 3: Not Set ; Assumed Clear

    MOD09Q1: Band-wise Data Quality 250m bits=[4-7][8-11]
    MOD09A1: Band-wise Data Quality 500m bits=[2-5][6-9][10-13][14-17][18-21][22-25][26-29]

- [0000]= class 0: highest quality
- [0111]= class 1: noisy detector
- [1000]= class 2: dead detector; data interpolated in L1B
- [1001]= class 3: solar zenith ge 86 degrees
- [1010]= class 4: solar zenith ge 85 and lt 86 degrees
- [1011]= class 5: missing input
- [1100]= class 6: internal constant used in place of climatological data for at least one atmospheric constant
- [1101]= class 7: correction out of bounds, pixel constrained to extreme allowable value
- [1110]= class 8: L1B data faulty
- [1111]= class 9: not processed due to deep ocean or cloud
- Class 10-15: Combination of bits unused

    MOD09A1/Q1: Atmospheric correction bit=[12]/[30]

- [0]= class 0: Not Corrected product
- [1]= class 1: Corrected product

    MOD09A1/Q1: Adjacency correction bit=[13]/[31]

- [0]= class 0: Not Corrected product
- [1]= class 1: Corrected product

    MOD09Q1: Different orbit from 500m product, bit=[14]

- [0]= class 0: same orbit as 500m
- [1]= class 1: different orbit from 500m

    MOD11A1: Mandatory QA Flags bits=[0-1]

- [00]= class 0: LST produced, good quality, not necessary to examine more detailed QA
- [01]= class 1: LST produced, other quality, recommend examination of more detailed QA
- [10]= class 2: LST not produced due to cloud effects
- [11]= class 3: LST not produced primarily due to reasons other than cloud

    MOD11A1: Data Quality Flag bits=[2-3]

- [00]= class 0: Good data quality of L1B in bands 31 and 32
- [01]= class 1: Other quality data
- [10]= class 2: TBD
- [11]= class 3: TBD

    MOD11A1: Emis Error Flag bits=[4-5]

- [00]= class 0: Average emissivity error le 0.01
- [01]= class 1: Average emissivity error le 0.02
- [10]= class 2: Average emissivity error le 0.04
- [11]= class 3: Average emissivity error gt 0.04

    MOD11A1: LST Error Flag bits=[6-7]

- [00]= class 0: Average LST error le 1
- [01]= class 1: Average LST error le 2
- [10]= class 2: Average LST error le 3
- [11]= class 3: Average LST error gt 3

    MOD11A2: Mandatory QA Flags bits=[0-1]

- [00]= class 0: LST produced, good quality, not necessary to examine more detailed QA
- [01]= class 1: LST produced, other quality, recommend examination of more detailed QA
- [10]= class 2: LST not produced due to cloud effects
- [11]= class 3: LST not produced primarily due to reasons other than cloud

    MOD11A2: Data Quality Flag bits=[2-3]

- [00]= class 0: Good data quality of L1B in 7 TIR bands
- [01]= class 1: Other quality data
- [10]= class 2: TBD
- [11]= class 3: TBD

    MOD11A2: Emis Error Flag bits=[4-5]

- [00]= class 0: Average emissivity error le 0.01
- [01]= class 1: Average emissivity error le 0.02
- [10]= class 2: Average emissivity error le 0.04
- [11]= class 3: Average emissivity error gt 0.04

    MOD11A2: LST Error Flag bits=[6-7]

- [00]= class 0: Average LST error le 1
- [01]= class 1: Average LST error le 2
- [10]= class 2: Average LST error le 3
- [11]= class 3: Average LST error gt 3

    MOD09A1s: Cloud State bits=[0-1]

- [00]= class 0: clear
- [01]= class 1: cloudy
- [10]= class 2: mixed
- [11]= class 3: not set, assumed clear

    MOD09A1s: Cloud shadow bits=[2]

- [0]= class 0: yes
- [1]= class 1: no

    MOD09A1s: Land/Water Flag bits=[3-5]

- [000]= class 0: Shallow ocean
- [001]= class 1: Land
- [010]= class 2: Ocean coastlines and lake shorelines
- [011]= class 3: Shallow inland water
- [100]= class 4: Ephemeral water
- [101]= class 5: Deep inland water
- [110]= class 6: Continental/moderate ocean
- [111]= class 7: Deep ocean

    MOD09A1s: Aerosol Quantity bits=[6-7]

- [00]= class 0: Climatology
- [01]= class 1: Low
- [10]= class 2: Average
- [11]= class 3: High

    MOD09A1s: Cirrus detected bits=[8-9]

- [00]= class 0: None
- [01]= class 1: Small
- [10]= class 2: Average
- [11]= class 3: High

    MOD09A1s: Internal Cloud Algorithm Flag bits=[10]

- [0]= class 0: Cloud
- [1]= class 1: No cloud

    MOD09A1s: Internal Fire Algorithm Flag bits=[11]

- [0]= class 0: Fire
- [1]= class 1: No fire

    MOD09A1s: MOD35 snow/ice flag bits=[12]

- [0]= class 0: Yes
- [1]= class 1: No

    MOD09A1s: Pixel adjacent to cloud bits=[13]

- [0]= class 0: Yes
- [1]= class 1: No

    MOD09A1s: BRDF correction performed bits=[14]

- [0]= class 0: Yes
- [1]= class 1: No

    MOD09A1s: Internal Snow Mask bits=[15]

- [0]= class 0: Snow
- [1]= class 1: No snow

    MOD13A2: Mandatory QA Flags 1Km bits[0-1]

- [00]= class 0: VI produced, good quality
- [01]= class 1: VI produced, but check other QA
- [10]= class 2: Pixel produced, but most probably cloud
- [11]= class 3: Pixel not produced due to other reasons than clouds

    MOD13A2: VI Usefulness Flag bits[2-5]

- [0000]= class 0: Highest quality
- [0001]= class 1: Lower quality
- [0010]= class 2: Decreasing quality
- [0100]= class 3: Decreasing quality
- [1000]= class 4: Decreasing quality
- [1001]= class 5: Decreasing quality
- [1010]= class 6: Decreasing quality
- [1100]= class 7: Lowest quality
- [1101]= class 8: Quality so low that it is not useful
- [1110]= class 9: L1B data faulty
- [1111]= class 10: Not useful for any other reason/not processed

    MOD13A2: Aerosol quantity Flags 1Km bits[6-7]

- [00]= class 0: Climatology
- [01]= class 1: Low
- [10]= class 2: Average
- [11]= class 3: High

    MOD13A2: Adjacent cloud detected 1Km bit[8]

- [00]= class 0: No
- [01]= class 1: Yes

    MOD13A2: Atmosphere BRDF correction performed 1Km bit[9]

- [00]= class 0: No
- [01]= class 1: Yes

    MOD13A2: Mixed clouds 1Km bit[10]

- [00]= class 0: No
- [01]= class 1: Yes

    MOD13A2: Land/Water Flags 1Km bits[11-13]

- [000]= class 0: Shallow Ocean
- [001]= class 1: Land (Nothing else but land)
- [010]= class 2: Ocean Coastlines and lake shorelines
- [011]= class 3: Shallow inland water
- [100]= class 4: Ephemeral water
- [101]= class 5: Deep inland water
- [110]= class 6: Moderate or continental ocean
- [111]= class 7: Deep ocean

    MOD13A2: Possible Snow/Ice 1Km bits[14]

- [0]= class 0: No
- [1]= class 1: Yes

    MOD13A2: Possible Shadow 1Km bits[15]

- [0]= class 0: No
- [1]= class 1: Yes

    MCD43B2: Albedo Quality Ancillary Platform Data 1Km bits[0-3]
    SDS: BRDF_Albedo_Ancillary

- [0000]= class 0: Satellite Platform: Terra
- [0001]= class 1: Satellite Platform: Terrra/Aqua
- [0010]= class 2: Satellite Platform: Aqua
- [1111]= class 15: Fill Value
- Classes 3-14: Not used

    MCD43B2: Albedo Quality Ancillary Land/Water Data 1Km bits[4-7]
    SDS: BRDF_Albedo_Ancillary

- [0000] class 0: Shallow Ocean
- [0001] class 1: Land (Nothing else but land)
- [0010] class 2: Ocean and lake shorelines
- [0011] class 3: Shallow inland water
- [0100] class 4: Ephemeral water
- [0101] class 5: Deep inland water
- [0110] class 6: Moderate or continental ocean
- [0111] class 7: Deep ocean
- [1111] class 15: Fill Value
- Classes 8-14: Not used

    MCD43B2: Albedo Quality Ancillary Sun Zenith Angle at Local Solar Noon Data 1Km bits[8-14]
    SDS: BRDF_Albedo_Ancillary

Returns integer value [0-90], 127 is Fill Value

    MCD43B2: Band-wise Albedo Quality Data 1Km
    SDS: BRDF_Albedo_Band_Quality

bits[0-3][4-7][8-11][12-15][16-19][20-23][24-27]

- [0000]= class 0: best quality, 75% or more with best full inversions
- [0001]= class 1: good quality, 75% or more with full inversions
- [0010]= class 2: Mixed, 50% or less full inversions and 25% or less fill values
- [0011]= class 3: All magnitude inversions or 50% or less fill values
- [0100]= class 4: 75% or more fill values
- Classes 5-14: Not Used
- [1111]= class 15: Fill Value

## NOTES

In MOD09A1: It seems that cloud related info is not filled properly in the standard QC (MOD09A1 in this module) since version 3, State-QA 500m images (MOD09A1s in this module) should be used (see Vermote et al., 2008).

## TODO

Add one Day products.

## SEE ALSO

i.vi

## REFERENCES

- MODIS Products
- Vermote E.F., Kotchenova S.Y., Ray J.P. MODIS Surface Reflectance User's Guide. Version 1.2. June 2008. MODIS Land Surface Reflectance Science Computing Facility. Homepage

## AUTHOR

Yann Chemin

Last changed: $Date$