VNP43IA1: Daily VIIRS BRDF Model Parameters for Surface Anisotropy

NASA/NOAA's Suomi NPP VIIRS VNP43IA1 product provides three spectrally dependent kernel weights—isotropic (fiso), volumetric (fvol), and geometric (fgeo)—at a 500-meter resolution to model the anisotropic reflectance of the Earth's surface. Generated daily using a 16-day rolling window of VIIRS data, these parameters are essential for correcting directional effects and deriving albedo products, promoting continuity with the MODIS BRDF/Albedo suite. The dataset employs the RossThick/Li-Sparse-Reciprocal (RTLSR) kernel-driven model and is packaged in HDF-EOS5 files containing six Science Dataset layers.

Use Cases

• Correcting directional reflectance to a common view geometry for consistent analysis based on the BRDF model parameters.
• Estimating black-sky albedo at any solar illumination angle using the provided kernel weights and a simple polynomial.
• Manually calculating instantaneous actual (blue-sky) albedo using the integrated black-sky and white-sky albedo Science Dataset layers.
• Studying land surface anisotropy and radiative properties over time at a global, 500-meter scale.

Strengths

• Provides a high spatial resolution of 500 meters for global BRDF analysis.
• Ensures temporal consistency by being produced daily using a weighted 16-day data composite.
• Supports continuity with the established MODIS BRDF/Albedo product suite.

Limitations

• Key metadata such as row count, file size, and specific column names are not provided across any source.
• The license is ambiguously listed as 'other-license-specified' without explicit terms.
• Documentation references external Algorithm Theoretical Basis Documents (ATBDs) which may not be directly included.

Provenance

Source

National Aeronautics and Space Administration (NASA)

Collection Method

Derived from Visible Infrared Imaging Radiometer Suite (VIIRS) sensor data aboard the Suomi NPP satellite.

Time Range

Daily production suggests continuous temporal coverage from the satellite's operational date onward.

Freshness

2026-04-09 20:56:07.232699

Geography

Global coverage on a 500m Sinusoidal (SIN) grid.