The Moderate Resolution Imaging Spectroradiometer (MODIS) MCD43A2 Version 6 Bidirectional Reflectance Distribution Function and Albedo (BRDF/Albedo) Quality dataset is produced daily using 16 days of Terra and Aqua MODIS data at 500 meter (m) resolution. Data are temporally weighted to the ninth day of the 16-day retrieval period which is reflected in the Julian date in the file name. MCD43A2 contains the quality information for the corresponding MCD43A3 Albedo and MCD43A4 Nadir BRDF-Adjusted Reflectance (NBAR) products.
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.
The MCD43A2 contains BRDF/Albedo band quality (inversion information) and days of valid observation within the 16-day period for MODIS bands 1 through 7 along with land water type, snow BRDF albedo, local solar noon, platform, and BRDF/Albedo uncertainty.
|File Size||~1 MB|
|Temporal Extent||2000-02-16 to Present|
|Geographic Dimensions||~1200 km x 1200 km|
|Number of Science Dataset (SDS) Layers||19|
|Columns/Rows||2400 x 2400|
|Pixel Size||~500 m|
|SDS Name||Description||Units||Data Type||Fill Value||No Data Value||Valid Range||Scale Factor|
|Snow_BRDF_Albedo||Snow-free BRDF/Albedo retrieved||Bit Field||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_Platform||BRDF Albedo Platform information||Bit Field||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_LandWaterType||Land Water Type||Bit Field||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_LocalSolarNoon||Solar Zenith Angle of Local Solar Noon||Bit Field||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_ValidObs_Band1||Valid Observation for Band 1||N/A||16-bit unsigned integer||0||N/A||1 to 65535||N/A|
|BRDF_Albedo_ValidObs_Band2||Valid Observation for Band 2||N/A||16-bit unsigned integer||0||N/A||1 to 65535||N/A|
|BRDF_Albedo_ValidObs_Band3||Valid Observation for Band 3||N/A||16-bit unsigned integer||0||N/A||1 to 65535||N/A|
|BRDF_Albedo_ValidObs_Band4||Valid Observation for Band 4||N/A||16-bit unsigned integer||0||N/A||1 to 65535||N/A|
|BRDF_Albedo_ValidObs_Band5||Valid Observation for Band 5||N/A||16-bit unsigned integer||0||N/A||1 to 65535||N/A|
|BRDF_Albedo_ValidObs_Band6||Valid Observation for Band 6||N/A||16-bit unsigned integer||0||N/A||1 to 65535||N/A|
|BRDF_Albedo_ValidObs_Band7||Valid Observation for Band 7||N/A||16-bit unsigned integer||0||N/A||1 to 65535||N/A|
|BRDF_Albedo_Band_Quality_Band1||BRDF Inversion Information for Band 1||Bit Field||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_Band_Quality_Band2||BRDF Inversion Information for Band 2||Bit Field||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_Band_Quality_Band3||BRDF Inversion Information for Band 3||Bit Field||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_Band_Quality_Band4||BRDF Inversion Information for Band 4||Bit Field||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_Band_Quality_Band5||BRDF Inversion Information for Band 5||Bit Field||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_Band_Quality_Band6||BRDF Inversion Information for Band 6||Bit Field||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_Band_Quality_Band7||BRDF Inversion Information for Band 7||Bit Field||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|BRDF_Albedo_Uncertainty||BRDF Albedo Uncertainty||N/A||16-bit unsigned integer||32767||N/A||0 to 32766||0.001|
Information for the Snow_BRDF_Albedo, BRDF_Albedo_Platform, BRDF_Albedo_LandWatertype, BRDF_Albedo_ValidObs_Band1 through 7, and BRDF_Albedo_Band_Quality_Band1 through 7 legends are available in the MCD43A2 File Specification.
The metadata information within the HDF file of the Version 6 MCD43A2 gives incorrect SDS layer parameters for BRDF_Albedo_ValidObs_Band1 through 7. The metadata states that the Valid Range is 0 to 32767 with a scaling factor of 0.001, which is incorrect. The Data Layers Characteristics section of this product page is accurate, the correct Valid Range is 0 to 65535 with no scaling factor.
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 the MCD43A2 known issues refer to the MODIS Land Quality Assessment website.