MYD13C2 v006

MODIS/Aqua Vegetation Indices Monthly L3 Global 0.05 Deg CMG

PI: Kamel Didan


The MYD13C2 Version 6 product provides a Vegetation Index (VI) value at a per pixel basis. There are two primary vegetation layers. The first is the Normalized Difference Vegetation Index (NDVI) which is referred to as the continuity index to the existing National Oceanic and Atmospheric Administration-Advanced Very High Resolution Radiometer (NOAA-AVHRR) derived NDVI. The second vegetation layer is the Enhanced Vegetation Index (EVI), which has improved sensitivity over high biomass regions.

The Climate Modeling Grid (CMG) consists of 3,600 rows and 7,200 columns of 5,600 meter (m) pixels. In generating this monthly product, the algorithm ingests all the MYD13A2 products that overlap the month and employs a weighted temporal average. Global MYD13C1 data are cloud-free spatial composites and are provided as a Level 3 product projected on a 0.05 degree (5,600 m) geographic CMG. The MYD13C2 has data fields for the NDVI, EVI, VI QA, reflectance data, angular information, and spatial statistics such as mean, standard deviation, and number of used input pixels at the 0.05 degree CMG resolution.

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Improvements/Changes from Previous Versions

  • The 16-day composite VI is generated using the two 8-day composite surface reflectance granules (MYD09A1) in the 16-day period.
  • This surface reflectance input is based on the minimum blue compositing approach used to generate the 8-day surface reflectance product.
  • The product format is consistent with the Version 5 product generated using the Level 2 gridded daily surface reflectance product.
  • A frequently updated long-term global CMG Average Vegetation Index product database is used to fill the gaps in the CMG product suite.

Product Maturity

Validation at stage 3 has been achieved for the MODIS Vegetation Index product suite. Further details regarding MODIS land product validation for the MYD13 data products are available from the MODIS Land Team Validation site.

Collection and Granule


Characteristic Description
CollectionAqua MODIS
File Size~99 MB
Temporal ResolutionMonthly
Temporal Extent2002-07-01 to Present
Spatial ExtentGlobal
Coordinate SystemGeographic Latitude and Longitude
File FormatHDF-EOS
Geographic DimensionsGlobal


Characteristic Description
Number of Science Dataset (SDS) Layers13
Columns/Rows7200 x 3600
Pixel Size5600 m


SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
CMG 0.05 Deg Monthly NDVI 16 day NDVI NDVI 16-bit signed integer -3000 N/A -2000 to 10000 0.0001
CMG 0.05 Deg Monthly EVI 16 day EVI EVI 16-bit signed integer -3000 N/A -2000 to 10000 0.0001
CMG 0.05 Deg Monthly VI Quality VI quality indicators Bit Field 16-bit unsigned integer 65535 N/A 0 to 65534 N/A
CMG 0.05 Deg Monthly red reflectance Surface Reflectance Band 1 N/A 16-bit signed integer -1000 N/A 0 to 10000 0.0001
CMG 0.05 Deg Monthly NIR reflectance Surface Reflectance Band 2 N/A 16-bit signed integer -1000 N/A 0 to 10000 0.0001
CMG 0.05 Deg Monthly blue reflectance Surface Reflectance Band 3 N/A 16-bit signed integer -1000 N/A 0 to 10000 0.0001
CMG 0.05 Deg Monthly MIR reflectance Surface Reflectance Band 7 N/A 16-bit signed integer -1000 N/A 0 to 10000 0.0001
CMG 0.05 Deg Monthly Avg sun zen angle Sun zenith angle of VI Pixel Degree 16-bit signed integer -10000 N/A -9000 to 9000 0.01
CMG 0.05 Deg Monthly NDVI std dev Standard deviation computed from input NDVI pixels NDVI 16-bit signed integer -3000 N/A 0 to 10000 0.0001
CMG 0.05 Deg Monthly EVI std dev Standard deviation computed from input EVI pixels EVI 16-bit signed integer -3000 N/A 0 to 10000 0.0001
CMG 0.05 Deg Monthly #1km pix used Number of 1 km input pixels used Number 8-bit unsigned integer 255 N/A 0 to 36 N/A
CMG 0.05 Deg Monthly #1km pix +-30deg VZ Number of 1km pixels used with VZ angle less than + or - 30 degs Number 8-bit unsigned integer 255 N/A 0 to 36 N/A
CMG 0.05 Deg Monthly pixel reliabilty Quality reliability of VI pixel Rank 8-bit signed integer -1 N/A 0 to 4 N/A

Product Quality

The "CMG 0.05 Deg Monthly VI Quality" layer is 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 quality layer.

The QA bit flags for the "CMG 0.05 Deg Monthly pixel reliabilty" layer are provided in Table 18 on page 27 and the "CMG 0.05 Deg Monthly VI Quality" layer in Table 5 on page 16 of the User Guide.

Known Issues

The incorrect representation of the aerosol quantities (low, average, high) in the Collection 6 MYD09 surface reflectance products may have impacted MYD13 Vegetation Index data products particularly over arid bright surfaces.

Corrections will be implemented in Collection 6.1 reprocessing in 2020.

For complete information about the MYD13C2 known issues please refer to the MODIS Land Quality Assessment website.

About the image

Aqua MODIS NDVI data from the MYD13C2 product across the globe, July 2018.

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User Guide
Algorithm Theoretical Basis Document (ATBD)
File Specification

Using the Data

Access Data


DOI: 10.5067/MODIS/MYD13C2.006