MCD43C4 v006

MODIS/Terra+Aqua BRDF/Albedo Nadir BRDF-Adjusted Reflectance Daily L3 Global 0.05 Deg CMG


PI: Crystal Schaaf

The MCD43C4 Version 6 data product was decommissioned on July 31, 2023. Users are encouraged to use the MCD43C4 Version 6.1 data product.

Description

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.

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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.
  • CMG Albedo is estimated using all the clear-sky observations within the 1,000 m grid for MCD43C as opposed to aggregating from the 500 m albedo.

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/MCD43C4.006
File Size~90.342 MB
Temporal ResolutionDaily
Temporal Extent2000-02-16 to 2023-02-17
Spatial ExtentGlobal
Coordinate SystemGeographic Latitude and Longitude
DatumN/A
File FormatHDF-EOS
Geographic DimensionsGlobal

Granule

Characteristic Description
Number of Science Dataset (SDS) Layers12
Columns/Rows7200 x 3600
Pixel Size5600 m

Layers / Variables

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

Quality bit index

Value Description
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
255 Fill Value

Known Issues

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 were implemented in Collection 6.1 reprocessing.

For complete information about the MCD43C4 known issues refer to the MODIS Land Quality Assessment website.


About the image

Combined MODIS BRDF Albedo nadir reflectance band 1 data from the MCD43C4 product across the globe, August 2, 2018.

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Documentation

User Guide
Algorithm Theoretical Basis Document (ATBD)
File Specification

Using the Data

Access Data

Citation

DOI: 10.5067/MODIS/MCD43C4.006