MCD43D31 v061

MODIS/Terra+Aqua BRDF/Albedo QA BRDF Quality Daily L3 Global 30 ArcSec CMG


PI: Crystal Schaaf

Historic processing continues for MODIS V6.1 data products for years 2011 through 2018. It is the intent to complete processing of the archive by the end of the 2021 calendar year. The V6 land products will be available until the V6.1 processing is completed, upon which time the MODIS V6 products will be decommissioned.

Description

The MCD43D31 Version 6.1 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.

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.

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.

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Characteristics

Improvements/Changes from Previous Versions

  • The Version 6.1 Level-1B (L1B) products have been improved by undergoing various calibration changes that include: changes to the response-versus-scan angle (RVS) approach that affects reflectance bands for Aqua and Terra MODIS, corrections to adjust for the optical crosstalk in Terra MODIS infrared (IR) bands, and corrections to the Terra MODIS forward look-up table (LUT) update for the period 2012 - 2017.
  • A polarization correction has been applied to the L1B Reflective Solar Bands (RSB).

Product Maturity

Validation at stage 3 has been achieved for all MODIS BRDF/Albedo products. Further details regarding MODIS land product validation for the MCD43 data products are available from the MODIS Land Team Validation site.

Collection and Granule

Collection

Characteristic Description
CollectionCombined MODIS
DOI10.5067/MODIS/MCD43D31.061
File Size~27 MB
Temporal ResolutionDaily
Temporal Extent2000-02-16 to Present
Spatial ExtentGlobal
Coordinate SystemGeographic Latitude and Longitude
DatumN/A
File FormatHDF-EOS
Geographic DimensionsGlobal

Granule

Characteristic Description
Number of Science Dataset (SDS) Layers8
Columns/Rows43200 x 21600
Pixel Size~1000 m

Layers

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

BRDF Quality description

Value Description
0 Processed, good quality, full BRDF inversions
1 Processed, magnitude BRDF inversions
255 Fill value

BRDF/Albedo Band Quality description

Value Description
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)
255 Fill value

Product Quality

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.

Known Issues

For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website.


About the image

Combined MODIS BRDF quality data from the MCD43D31 product across the globe, August 10, 2020.

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Documentation

User Guide
Algorithm Theoretical Basis Document (ATBD)
File Specification

Using the Data

Access Data

Citation

DOI: 10.5067/MODIS/MCD43D31.061