N: 90 S: -90 E: 180 W: -180
Description
The Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) Vegetation Indices (MYD13A3) 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 MYD13A2 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.
Known Issues
- For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website.
Version Description
Product Summary
Citation
Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.
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File Naming Convention
The file name begins with the Product Short Name (MYD13A3) followed by the Julian Date of Acquisition formatted as AYYYYDDD (A2025182), the Tile Identifier which is horizontal tile and vertical tile provided as hXXvYY (h28v14), the Version of the data collection (061), the Julian Date and Time of Production designated as YYYYDDDHHMMSS (2025217235935), and the Data Format (hdf).
Documents
USER'S GUIDE
ALGORITHM THEORETICAL BASIS DOCUMENT (ATBD)
PRODUCT QUALITY ASSESSMENT
SCIENCE DATA PRODUCT VALIDATION
Publications Citing This Dataset
Variables
The table below lists the variables contained within a single granule for this dataset. Variables often contain observed or derived geophysical measurements collected from a variety of sources, including remote sensing instruments on satellite and airborne platforms, field campaigns, in situ measurements, and model outputs. The terms variable, parameter, scientific data set, layer, and band have been used across NASA’s Earth science disciplines; however, variable is the designated nomenclature in NASA’s Common Metadata Repository (CMR). Variable metadata attributes such as Name, Description, Units, Data Type, Fill Value, Valid Range, and Scale Factor allow users to efficiently process and analyze the data. The full range of attributes may not be applicable to all variables. Additional information on variable attributes is typically available in the data, user guide, and/or other product documentation.
For questions on a specific variable, please use the Earthdata Forum.
| Name Sort descending | Description | Units | Data Type | Fill Value | Valid Range | Scale Factor |
|---|---|---|---|---|---|---|
| 1 km monthly blue reflectance | Surface Reflectance Band 3 | N/A | int16 | -1000 | 0 to 10000 | 0.0001 |
| 1 km monthly EVI | 1 km monthly EVI | EVI | int16 | -3000 | -2000 to 10000 | 0.0001 |
| 1 km monthly MIR reflectance | Surface Reflectance Band 7 | N/A | int16 | -1000 | 0 to 10000 | 0.0001 |
| 1 km monthly NDVI | 1 km monthly NDVI | NDVI | int16 | -3000 | -2000 to 10000 | 0.0001 |
| 1 km monthly NIR reflectance | Surface Reflectance Band 2 | N/A | int16 | -1000 | 0 to 10000 | 0.0001 |
| 1 km monthly pixel reliability | Quality reliability of VI pixel | Rank | int8 | -1 | 0 to 3 | N/A |
| 1 km monthly red reflectance | Surface Reflectance Band 1 | N/A | int16 | -1000 | 0 to 10000 | 0.0001 |
| 1 km monthly relative azimuth angle | Relative azimuth angle of VI pixel | Degree | int16 | -4000 | -18000 to 18000 | 0.01 |
| 1 km monthly sun zenith angle | Sun zenith angle of VI pixel | Degree | int16 | -10000 | 0 to 18000 | 0.01 |
| 1 km monthly view zenith angle | View zenith angle of VI Pixel | Degree | int16 | -10000 | 0 to 18000 | 0.01 |
| 1 km monthly VI Quality | VI quality indicators | Bit Field | uint16 | 65535 | 0 to 65534 | N/A |