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Full catalog/VJ143DNBA4
VJ143DNBA4·v002·dataset

True land reflectance corrected for sun angle (VIIRS NOAA-20, 1 km)

VIIRS/JPSS1 DNB 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. Shows what the land surface reflectance would look like if the satellite were always staring straight down, removing the distortion caused by viewing the ground from different angles.

How it's made. Built from 16 days of VIIRS day/night-band data on NOAA-20, corrected to a common straight-down view using a reflectance model and weighted to the ninth day.

How & where you'd use it. Gives researchers a clean, angle-corrected reflectance layer for tracking vegetation and land-surface change consistently over time, designed to extend the older MODIS record.

What's measured

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

Coverage & cadence

  • Time span2018-01-05 → 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) Day/Night Band (DNB) Nadir Bidirectional Reflectance Distribution Function (BRDF) Adjusted Reflectance (NBAR) Version 2 product provides NBAR estimates at 1 kilometer (km) resolution. The VJ143DNBA4 product is produced daily using 16 days of VIIRS data and is weighted temporally to the ninth day, which is reflected in the file name. The view angle effects are removed from the directional reflectance 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. The VJ143 algorithm uses the RossThick/Li-Sparse-Reciprocal (RTLSR) semi-empirical kernel-driven BRDF model, with the three kernel weights from [VJ143DNBA1](https://doi.org/10.5067/VIIRS/VJ143DNBA1.002) to reconstruct surface anisotropic effects, correcting the directional reflectance to a common view geometry (VJ143DNBA4), while also computing integrated black-sky albedo (BSA) at local solar noon and white-sky albedo (WSA) ([VJ143DNBA3](https://doi.org/10.5067/VIIRS/VJ143DNBA3.002)). 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 VJ143DNBA4 product includes BRDF/Albedo mandatory quality and nadir reflectance for the VIIRS DNB. A low-resolution browse image is also available showing NBAR of the DNB as a red, green, blue (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

vj143dnba4_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="VJ143DNBA4",
    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.