MCD43A2 v006

MODIS/Terra+Aqua BRDF/Albedo Quality Daily L3 Global 500 m SIN Grid


PI: Crystal Schaaf

Description

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.

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.

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Characteristics

Improvements/Changes from Previous Versions

  • Observations are weighted to estimate the BRDF/Albedo on the ninth day of the 16-day period.
  • MCD43 products use the snow status weighted to the ninth day instead of the majority snow/no-snow observations from the 16-day period.
  • Better quality at high latitudes from use of all available observations for the acquisition period. Collection 5 used only four observations per day.
  • The MCD43 products use L2G-lite surface reflectance as input.
  • When there are insufficient high quality reflectances, a database with archetypal BRDF parameters is used to supplement the observational data and perform a lower quality magnitude inversion. This database is continually updated with the latest full inversion retrieval for each pixel.

Product Maturity

The MODIS BRDF/ALBEDO products have achieved stage 3 validation.

Collection and Granule

Collection

Characteristic Description
CollectionCombined MODIS
DOI10.5067/MODIS/MCD43A2.006
File Size~1 MB
Temporal ResolutionDaily
Temporal Extent2000-02-16 to Present
Spatial ExtentGlobal
Coordinate SystemSinusoidal
DatumN/A
File FormatHDF-EOS
Geographic Dimensions~1200 km x 1200 km

Granule

Characteristic Description
Number of Science Dataset (SDS) Layers19
Columns/Rows2400 x 2400
Pixel Size~500 m

Layers

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.

Known Issues

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 Collection 6 MYD09 and MOD09 surface reflectance products may have impacted MCD43 BRDF/Albedo data products particularly over arid bright surfaces.

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.

Documentation

Using the Data

Access Data

Citation

DOI: 10.5067/MODIS/MCD43A2.006

About the Image

Combined MODIS BRDF Albedo Valid Observations 1-4-3 data from the MCD43A2 product over western United States June 7, 2018.

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