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Full catalog/VJ143MA4
VJ143MA4·v002·dataset

Surface reflectance corrected for sun angle (VIIRS NOAA-20, daily 1 km)

VIIRS/JPSS1 BRDF/Albedo Nadir BRDF-Adjusted Ref Daily L3 Global 1km SIN Grid V002
land NASA LPCLOUD Level 3 active HDF-EOS5
In plain English

What it measures. Surface reflectance — how much sunlight the land bounces back — adjusted so it looks as if the satellite were always viewing straight down, removing the distortions caused by changing view angles. This makes day-to-day comparisons more reliable.

How it's made. Created daily from 16 days of VIIRS data on the NOAA-20 satellite, gridded globally at 1 km, using a model that corrects for viewing and sun geometry; it's designed to continue NASA's older MODIS record.

How & where you'd use it. Gives researchers a clean, consistent measure of surface brightness for tracking vegetation, land cover, and surface changes over time.

What's measured

LAND SURFACE › SURFACE RADIATIVE PROPERTIES › REFLECTANCELAND SURFACE › SURFACE RADIATIVE PROPERTIES › ANISOTROPYLAND SURFACE › SURFACE RADIATIVE PROPERTIES › ALBEDO

Coverage & cadence

  • Time span2018-01-01 → ongoing
  • Measured byNOAA-20 (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 NOAA-20 Visible Infrared Imaging Radiometer Suite (VIIRS) Nadir Bidirectional Reflectance Distribution Function (BRDF) Adjusted Reflectance (NBAR) Version 2 product provides NBAR estimates at 1 kilometer (km) resolution. The VJ143MA4 product is produced daily using 16-day VIIRS data and is weighted temporally to the 9th day, which is reflected in the file name. The view angle effects are removed from the directional reflectances resulting in a stable and consistent NBAR product. The VJ143 data products are designed after the Moderate Resolution Imaging Spectroradiometer (MODIS) BRDF/Albedo product suite to promote the continuity of the Earth Observation System (EOS) mission. The VJ143 data products are designed to promote the continuity of NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) BRDF/Albedo data product suite. The VJ143 algorithm uses the RossThick/Li-Sparse-Reciprocal (RTLSR) semi-empirical kernel-driven BRDF model, with the three kernel weights from [VJ143MA1](https://doi.org/10.5067/VIIRS/VJ143MA1.002) to reconstruct surface anisotropic effects, correcting the directional reflectance to a common view geometry (VJ143MA4), while also computing integrated black-sky albedo (BSA) at local solar noon and white-sky albedo (WSA) ([VJ143MA3](https://doi.org/10.5067/VIIRS/VJ143MA3.002)). 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 VJ143MA4 product includes eighteen SDS variables for BRDF/Albedo mandatory quality and nadir reflectance for VIIRS nine moderate bands M1-M5, M7-M8, and M10-M11. A low-resolution browse image is also available showing NBAR bands M5, M7, and M5 as an RGB 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

vj143ma4_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="VJ143MA4",
    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.