Earth Data School
About
Full catalog/VNP18C2
VNP18C2·v002·dataset

Sunlight plants can use, daily (VIIRS, Suomi-NPP, 0.05°)

VIIRS/NPP Photosynthetically Active Radiation Daily L3 Global 0.05Deg CMG V002
land NASA LPCLOUD Level 3 active HDF-EOS5
In plain English

What it measures. How much daily sunlight reaches the ground in the visible range that plants use for photosynthesis (called PAR).

How it's made. Produced from the VIIRS sensor on the Suomi-NPP satellite, combined onto a roughly 5-km global grid using look-up tables that account for clouds and haze.

How & where you'd use it. An important input for models of plant growth and land-surface processes, helping scientists study how much energy ecosystems have available for photosynthesis.

What's measured

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

Coverage & cadence

  • Time span2012-01-19 → 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 VNP18C2 Version 2 is a NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) Photosynthetically Active Radiation (PAR) Level 3 CMG product produced at 0.05 degree pixel resolution at daily intervals. PAR is incident solar radiation in the visible spectrum (400-700 nanometers) and is an important variable in land-surface models that address a variety of scientific and application issues. The VNP18 algorithm adapts the narrowband look-up table (LUT) approach to estimate DSR. The LUTs consider different types of loadings of aerosols and clouds at a variety of illumination/viewing geometry. Additional details regarding the methodology used to create the data are available in the Algorithm Theoretical Basis Document (ATBD). The VNP18C2 product is aggregated from VNP18A2 files and includes one set of global 3-hour PAR variables and one set of daily mean PAR.

Get the data

vnp18c2_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="VNP18C2",
    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.