MODIS Daily Photosynthetically Active Radiation at 1km Resolution

MCD18A2 Version 6.1 is a decommissioned NASA MODIS data product providing global, daily estimates of Photosynthetically Active Radiation (PAR) at 1-kilometer pixel resolution. The dataset combines observations from the Terra and Aqua satellites to produce instantaneous and 3-hourly PAR arrays using a look-up table algorithm accounting for aerosols and clouds. It was produced by the LPCLOUD organization and superseded by Version 6.2 as of June 1, III.

Use Cases

• Modeling terrestrial photosynthesis and carbon uptake using the 3-hour PAR arrays.
• Studying diurnal patterns of solar energy available for vegetation via the instantaneous PAR layers.
• Assessing surface radiative properties and albedo with the View Zenith Angle layer.
• Input for ecological and agricultural models requiring spatially explicit light availability data.
• Calibration and validation of other satellite-derived radiation products.

Strengths

• Provides data at a high spatial resolution of 1 kilometer per pixel.
• Offers high temporal frequency with both daily composites and 3-hourly estimates.
• Algorithm uses multi-temporal MODIS signatures and look-up tables considering varied aerosol/cloud loads and geometry.
• Cross-platform presence on NASA Earthdata and Data.gov signals its established use in the scientific community.

Limitations

• The dataset is decommissioned; users are directed to use the newer MCD18A2 Version 6.2 product.
• Sources conflict on the last updated date, reporting both 2024-06-01 and 2026-03-12.
• Specific row counts, file sizes, and a complete column list are not provided by any source.

Provenance

Source

NASA LPCLOUD, derived from MODIS sensors on Terra and Aqua satellites.

Collection Method

Generated using a prototyping algorithm that derives surface reflectance from MODIS data and calculates PAR via a look-up table (LUT) approach.

Time Range

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Freshness

2026-03-12 23:36:52.458173

Geography

Global coverage.