MOD13A3 v061

MODIS/Terra Vegetation Indices Monthly L3 Global 1 km SIN Grid

PI: Kamel Didan


The Terra Moderate Resolution Imaging Spectroradiometer (MODIS) Vegetation Indices Monthly (MOD13A3) Version 6.1 data are provided monthly at 1 kilometer (km) spatial resolution as a gridded Level 3 product in the sinusoidal projection. In generating this monthly product, the algorithm ingests all the MOD13A2 products that overlap the month and employs a weighted temporal average.

The MODIS Normalized Difference Vegetation Index (NDVI) complements NOAA's Advanced Very High Resolution Radiometer (AVHRR) NDVI products and provides continuity for time series historical applications. MODIS also includes an Enhanced Vegetation Index (EVI) that minimizes canopy background variations and maintains sensitivity over dense vegetation conditions. The EVI uses the blue band to remove residual atmosphere contamination caused by smoke and sub-pixel thin clouds. The MODIS NDVI and EVI products are computed from surface reflectances corrected for molecular scattering, ozone absorption, and aerosols.

Vegetation indices are used for global monitoring of vegetation conditions and are used in products displaying land cover and land cover changes. These data may be used as input for modeling global biogeochemical and hydrologic processes as well as global and regional climate. Additional applications include characterizing land surface biophysical properties and processes, such as primary production and land cover conversion.

Provided along with the vegetation layers and the two quality assurance (QA) layers are reflectance bands 1 (red), 2 (near-infrared), 3 (blue), and 7 (mid-infrared), as well as three observation layers.

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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 the MODIS Vegetation Index product suite. Further details regarding MODIS land product validation for the MOD13 data products are available from the MODIS Land Team Validation site.

Collection and Granule


Characteristic Description
CollectionTerra MODIS
File Size~8 MB
Temporal ResolutionMonthly
Temporal Extent2000-02-01 to Present
Spatial ExtentGlobal
Coordinate SystemSinusoidal
File FormatHDF-EOS
Geographic Dimensions1200 km x 1200 km


Characteristic Description
Number of Science Dataset (SDS) Layers11
Columns/Rows1200 x 1200
Pixel Size1000 m


SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
1 km monthly NDVI 1 km monthly NDVI NDVI 16-bit signed integer -3000 N/A -2000 to 10000 0.0001
1 km monthly EVI 1 km monthly EVI EVI 16-bit signed integer -3000 N/A -2000 to 10000 0.0001
1 km monthly VI Quality VI Quality indicators Bit Field 16-bit unsigned integer 65535 N/A 0 to 65534 N/A
1 km monthly red reflectance Surface Reflectance Band 1 N/A 16-bit signed integer -1000 N/A 0 to 10000 0.0001
1 km monthly NIR reflectance Surface Reflectance Band 2 N/A 16-bit signed integer -1000 N/A 0 to 10000 0.0001
1 km monthly blue reflectance Surface Reflectance Band 3 N/A 16-bit signed integer -1000 N/A 0 to 10000 0.0001
1 km monthly MIR reflectance Surface Reflectance Band 7 N/A 16-bit signed integer -1000 N/A 0 to 10000 0.0001
1 km monthly view zenith angle View zenith angle of VI Pixel Degree 16-bit signed integer -10000 N/A 0 to 18000 0.01
1 km monthly sun zenith angle Sun zenith angle of VI pixel Degree 16-bit signed integer -10000 N/A 0 to 18000 0.01
1 km monthly relative azimuth angle Relative azimuth angle of VI pixel Degree 16-bit signed integer -4000 N/A -18000 to 18000 0.01
1 km monthly pixel reliability Quality reliability of VI pixel Rank 8-bit signed integer -1 N/A 0 to 3 N/A

Product Quality

The "1 km 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 "1 km monthly pixel reliability" layer are provided in Table 4 and the "1 km monthly VI Quality" layer in Table 5 of the User Guide.

In areas where no valid VI is retrieved, VI Quality bits 11-13 are correctly assigned to indicate the land/water type. The other bits are set to 1 which can create a false notion of the parameter description; however, since no valid VI is retrieved these values can be ignored.

Known Issues

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


User Guide
Algorithm Theoretical Basis Document (ATBD)
File Specification

Using the Data

Access Data


DOI: 10.5067/MODIS/MOD13A3.061

About the Image

Terra MODIS NDVI data from the MOD13A3 product over part of Brazil, July 2020.

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