Description
MCD18A2 Version 6 was decommissioned on October 28, 2022. Users are encouraged to use the MCD18A2 Version 6.2 data product.
The MCD18A2 Version 6 is a Moderate Resolution Imaging Spectroradiometer (MODIS) Terra and Aqua combined Photosynthetically Active Radiation (PAR) gridded Level 3 product produced daily at 5 kilometer pixel resolution with estimates of PAR every 3 hours. PAR is incident solar radiation in the visible spectrum (400-700 nanometers) and is an important variable in land-surface models that address a variety of scientific and application issues. The MCD18 products are based on a prototyping algorithm that uses multi-temporal signatures of MODIS data to derive surface reflectance and then calculate incident PAR using the look-up table (LUT) approach. The LUTs consider different types of loadings of aerosols and clouds at a variety of illumination/viewing geometry. Global PAR products are generated from MODIS and geostationary satellite data. Additional details regarding the methodology used to create the data are available in the Algorithm Theoretical Basis Document (ATBD).
Provided in the MOD18A2 product are layers for instantaneous PAR array for each individual MODIS overpass and 3-hour PAR array along with a View Zenith Angle layer.
Known Issues
- For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website.
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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Documents
ALGORITHM THEORETICAL BASIS DOCUMENT (ATBD) | The ATBD provides physical theory and mathematical procedures for the calculations used to produce the data products. | |
GENERAL DOCUMENTATION | The File Specification provides a description of the product file including Scientific Data Sets and their attributes. | |
PRODUCT QUALITY ASSESSMENT | The LDOPE Land Product Quality Assessment website provides known issues, maneuvers, and product quality of the land products. | |
USER'S GUIDE | The technical information in the User's Guide enables users to interpret and use the data products. |