VNP43IA4: Daily Nadir BRDF-Adjusted Reflectance at 500m

NASA/NOAA's Suomi NPP VIIRS VNP43IA4 product provides daily, 500-meter resolution Nadir Bidirectional Reflectance Distribution Function (BRDF) Adjusted Reflectance (NBAR) estimates. It is generated daily using a 16-day data window, applying the RossThick/Li-Sparse-Reciprocal BRDF model to correct for view-angle effects and produce stable surface reflectance for VIIRS imagery bands I1, I2, and I3. The dataset supports continuity with MODIS products and enables the calculation of black-sky and white-sky albedo.

Use Cases

• Monitoring land surface change using corrected, angle-independent reflectance values.
• Calculating black-sky albedo at any solar illumination angle using the provided BRDF model parameters.
• Estimating instantaneous actual (blue-sky) albedo by combining the black-sky and white-sky albedo Science Dataset layers.
• Continuity studies comparing VIIRS NBAR data with legacy MODIS BRDF/Albedo products.

Strengths

• Provides daily global coverage at a consistent 500-meter spatial resolution.
• Applies a sophisticated BRDF correction (RTLSR model) to remove view-angle effects, producing stable reflectance.
• Designed for continuity with NASA's MODIS BRDF/Albedo product suite, supporting long-term time-series analysis.

Limitations

• Key metadata such as row count, specific column names, and file size are not provided on any platform.
• The 'last updated' date of 2026-04-09 appears to be a future date, indicating potential metadata freshness issues.
• Relies on a 16-day rolling window for daily product generation, which may smooth out very rapid surface changes.

Provenance

Source

NASA/NOAA Suomi NPP satellite, Visible Infrared Imaging Radiometer Suite (VIIRS) sensor.

Collection Method

Satellite remote sensing data processed through the VNP43 algorithm (Version 2).

Freshness

2026-04-09 20:43:49.567702 (Note: This is a future date, suggesting a metadata anomaly.)

Geography

Global