The Moderate Resolution Imaging Spectroradiometer (MODIS) MCD43C4 Version 6 Bidirectional Reflectance Distribution Function and Albedo (BRDF/Albedo) Nadir BRDF-Adjusted Reflectance (NBAR) dataset is produced daily using 16 days of Terra and Aqua MODIS data in a 0.05 degree (5,600 meters at the equator) Climate Modeling Grid (CMG). Data are temporally weighted to the ninth day of the retrieval period which is reflected in the Julian date in the file name. This CMG product covers the entire globe for use in climate simulation models.
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.
MCD43C4 removes view angle effects from directional reflectances to model the values as if they were collected from a nadir view at local solar noon. These NBAR values are calculated from MCD43C1. The product includes separate NBAR layers for MODIS spectral bands 1 through 7 as well as ancillary layers for quality, local solar noon, percent finer resolution inputs, snow cover, and uncertainty.
The MODIS BRDF/Albedo products have achieved stage 3 validation.
|File Size||~90.342 MB|
|Temporal Extent||2000-02-16 to Present|
|Coordinate System||Geographic Latitude and Longitude|
|Number of Science Dataset (SDS) Layers||12|
|Columns/Rows||7200 x 3600|
|Pixel Size||5600 m|
|SDS Name||Description||Units||Data Type||Fill Value||No Data Value||Valid Range||Scale Factor|
|Nadir_Reflectance_Band1||Nadir reflectance for MODIS band 1||N/A||16-bit signed integer||32767||N/A||0 to 32766||0.001|
|Nadir_Reflectance_Band2||Nadir reflectance for MODIS band 2||N/A||16-bit signed integer||32767||N/A||0 to 32766||0.001|
|Nadir_Reflectance_Band3||Nadir reflectance for MODIS band 3||N/A||16-bit signed integer||32767||N/A||0 to 32766||0.001|
|Nadir_Reflectance_Band4||Nadir reflectance for MODIS band 4||N/A||16-bit signed integer||32767||N/A||0 to 32766||0.001|
|Nadir_Reflectance_Band5||Nadir reflectance for MODIS band 5||N/A||16-bit signed integer||32767||N/A||0 to 32766||0.001|
|Nadir_Reflectance_Band6||Nadir reflectance for MODIS band 6||N/A||16-bit signed integer||32767||N/A||0 to 32766||0.001|
|Nadir_Reflectance_Band7||Nadir reflectance for MODIS band 7||N/A||16-bit signed integer||32767||N/A||0 to 32766||0.001|
|BRDF_Quality||Global albedo quality||N/A||8-bit unsigned integer||255||N/A||0 to 254||N/A|
|Local_Solar_Noon||Local solar noon zenith angle||Degree||8-bit unsigned integer||255||N/A||0 to 90||N/A|
|Percent_Inputs||Processed finer resolution data that contributed to this CMG pixel||Percent||8-bit unsigned integer||255||N/A||0 to 100||N/A|
|Percent_Snow||Underlying data flagged as snow||Percent||8-bit unsigned integer||255||N/A||0 to 100||N/A|
|BRDF_Albedo_Uncertainty||BRDF inversion information||N/A||16-bit unsigned integer||32767||N/A||0 to 32766||0.001|
|0||Best quality, 100% with full inversions|
|1||Good quality, 75% or more with best full inversions and 90% or more with full inversions|
|2||Relative good quality, 75% or more with full inversions|
|3||Mixed, 75% or less full inversions and 25% or less fill values|
|4||All magnitude inversions or 50% or less fill values|
|5||50% or more fill values|
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 MCD43C4 known issues refer to the MODIS Land Quality Assessment website.