Combined MODIS BRDF quality data from the MCD43D31 product across the globe, August 2, 2018.View full-size image
The MCD43D31 Version 6 Bidirectional Reflectance Distribution Function and Albedo (BRDF/Albedo) QA BRDF Quality dataset is produced daily using 16 days of Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) data at 30 arc second (1,000 meter (m)) resolution. Data are temporally weighted to the ninth day which is reflected in the Julian date in the file name. This Climate Modeling Grid (CMG) product covers the entire globe for use in climate simulation models. MCD43D31 provides BRDF/Albedo quality information for the MCD43D products.
MCD43D31 consists of a BRDF quality layer representing the overall quality of each pixel along with an individual BRDF/Albedo quality layer for MODIS spectral bands 1 through 7.
Users are urged to use the band specific quality flags to isolate the highest quality full inversion results for their own science applications as described in the User Guide.
|File Size||~26.9 MB|
|Temporal Extent||2000-02-16 to Present|
|Coordinate System||Geographic Latitude and Longitude|
|Number of Science Dataset (SDS) Layers||8|
|Columns/Rows||43200 x 21600|
|Pixel Size||~1000 m|
|SDS Name||Description||Units||Data Type||Fill Value||No Data Value||Valid Range||Scale Factor|
|BRDF_Quality||BRDF quality||N/A||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_Band_Quality_Band1||BRDF/Albedo quality for MODIS band 1||N/A||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_Band_Quality_Band2||BRDF/Albedo quality for MODIS band 2||N/A||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_Band_Quality_Band3||BRDF/Albedo quality for MODIS band 3||N/A||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_Band_Quality_Band4||BRDF/Albedo quality for MODIS band 4||N/A||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_Band_Quality_Band5||BRDF/Albedo quality for MODIS band 5||N/A||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_Band_Quality_Band6||BRDF/Albedo quality for MODIS band 6||N/A||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_Band_Quality_Band7||BRDF/Albedo quality for MODIS band 7||N/A||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|0||Processed, good quality, full BRDF inversions|
|1||Processed, magnitude BRDF inversions|
|0||Best quality, full inversion (Weight of Determination (WoDs), Root Mean Square Error (RMSE) majority good)|
|1||Good quality, full inversion (also including the cases that no clear sky observations over the day of interest or the Solar Zenith Angle is too large even WoDs, RMSE majority good)|
|2||Magnitude inversion (numobs >=7)|
|3||Magnitude inversion (numobs >=2 & <7)|
The quality layers are stored in an efficient bit-encoded manner. The unpack_sds_bits executable from the LDOPE Tools is available to the user community to help parse and interpret the QC layers.
The incorrect representation of the aerosol quantities (low average high) in the C6 MYD09 and MOD09 surface reflectance products may have impacted downstream products particularly over arid bright surfaces. This (and a few other issues) have been corrected for C6.1. Therefore users should avoid substantive use of the C6 MCD43 products and wait for the C6.1 products. In any event, users are always strongly encouraged to download and use the extensive QA data provided in MCD43A2, in addition to the briefer mandatory QAs provided as part of the MCD43A1, 3, and 4 products.
Corrections will be implemented in Collection 6.1 reprocessing in 2020.
For complete information about MCD43D31 known issues refer to the MODIS Land Quality Assessment website.