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Full catalog/VNP43IA1
VNP43IA1·v002·dataset

Settings for modeling surface reflection and brightness (Suomi-NPP, daily, 500 m)

VIIRS/NPP BRDF/Albedo Model Parameters Daily L3 Global 500m SIN Grid V002
land NASA LPCLOUD Level 3 active HDF-EOS5
In plain English

What it measures. Provides the mathematical model settings (kernel weights) used to describe how the Earth's surface reflects light from different angles, at 500 m resolution.

How it's made. Produced daily from 16 days of VIIRS data on the Suomi-NPP satellite, following the same modeling approach as NASA's MODIS reflectance/albedo products.

How & where you'd use it. A technical building-block product; researchers use these parameters to compute surface brightness (albedo) and to correct reflectance to a common viewing angle, rather than using it directly.

What's measured

LAND SURFACE › SURFACE RADIATIVE PROPERTIES › REFLECTANCELAND SURFACE › SURFACE RADIATIVE PROPERTIES › ALBEDOLAND SURFACE › SURFACE RADIATIVE PROPERTIES › ANISOTROPY

Coverage & cadence

  • Time span2012-01-17 → ongoing
  • Measured bySuomi-NPP (VIIRS)
  • Processing levelLevel 3
  • Spatial extent-180, -90, 180, 90
  • FormatsHDF-EOS5
  • StatusACTIVE

What you can do with it

  • Track deforestation, fire scars and land-cover change
  • Monitor crop and vegetation health (NDVI/EVI)
  • Map how built-up vs. green an area is over time
Official description

The NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) Bidirectional Reflectance Distribution Function (BRDF) and Albedo Model Parameters (VNP43IA1) Version 2 product provides kernel weights (parameters) at 500 meter (m) resolution. The VNP43IA1 product is produced daily using 16 days of VIIRS data, temporally weighted to the ninth day, which is reflected in the file name. The VNP43IA1 product provides three spectrally dependent kernel weights, also known as model parameters: isotropic (fiso), volumetric (fvol), and geometric (fgeo), which can be used to model anisotropic effects of the Earth’s surface. All VNP43 data products are designed to promote the continuity of NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) BRDF/Albedo data product suite. The VNP43 algorithm uses the RossThick/Li-Sparse-Reciprocal (RTLSR) semi-empirical kernel-driven BRDF model, with the three kernel weights from VNP43IA1 to reconstruct surface anisotropic effects, correcting the directional reflectance to a common view geometry ([VNP43IA4](https://doi.org/10.5067/VIIRS/VNP43IA4.002)), while also computing integrated black-sky albedo (BSA) at local solar noon and white-sky albedo (WSA) ([VNP43IA3](https://doi.org/10.5067/VIIRS/VNP43IA3.002)). Researchers can use the BRDF model parameters with a simple polynomial, to obtain black-sky albedo at any solar illumination angle. Likewise, both the BSA and WSA Science Dataset (SDS) variables can be used with a simple polynomial, to manually estimate instantaneous actual albedo (blue-sky albedo). Additional details regarding the methodology are available in the Algorithm Theoretical Basis Document (ATBD). The VNP43IA1 data product provides a total of six SDS variables including: three mandatory quality layers for bands I1, I2, and I3 and three multi-dimensional model parameter bands representing fiso, fvol, and fgeo for each imagery band. Each data product file is provided in HDF-EOS5 format. A low-resolution browse is also available showing BRDF/Albedo parameters for VIIRS imagery bands: I1, I2, and I1 as an RGB (red, green, blue) image in JPEG format. Known Issues * For complete information about known issues please refer to the [MODIS/VIIRS Land Quality Assessment website](https://landweb.modaps.eosdis.nasa.gov/knownissue?sensor=VIIRS).

Get the data

vnp43ia1_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="VNP43IA1",
    version="002",
    bounding_box=(-122.5, 37.2, -121.8, 37.9),  # your area (W,S,E,N)
    temporal=("2024-01-01", "2024-12-31"),       # your dates
)
files = earthaccess.open(results)   # stream straight from LPCLOUD
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.