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Full catalog/VJ117A2GF
VJ117A2GF·v002·dataset

How much carbon plants take in, gap-filled (NOAA-20, 8-day, 500 m)

VIIRS/JPSS1 Gross Primary Productivity and Net Photosynthesis Gap-Filled 8-Day L4 Global 500m SIN Grid V002
atmosphere NASA LPCLOUD Level 4 active HDF-EOS5
In plain English

What it measures. How much carbon plants absorb through photosynthesis (gross primary productivity and net photosynthesis), mapped globally at 500-meter detail every eight days, with gaps in the data filled in.

How it's made. Computed from the VIIRS instrument on the NOAA-20 satellite using a light-use-efficiency approach; poor-quality readings are cleaned and gaps filled by interpolation, so the product is finalized at year's end.

How & where you'd use it. Used to study how much carbon ecosystems take up and to model energy, carbon and water cycling in vegetation.

What's measured

ATMOSPHERE › ATMOSPHERIC WATER VAPOR › WATER VAPOR PROCESSES › EVAPOTRANSPIRATIONATMOSPHERE › ATMOSPHERIC WATER VAPOR › WATER VAPOR PROCESSES › EVAPORATIONATMOSPHERE › PRECIPITATION › PRECIPITATION PROFILES › LATENT HEAT FLUXBIOSPHERE › VEGETATION › VEGETATION PRODUCTIVITY

Coverage & cadence

  • Time span2018-01-01 → ongoing
  • Measured byNOAA-20 (VIIRS)
  • Processing levelLevel 4
  • Spatial extent-180, -90, 180, 90
  • FormatsHDF-EOS5
  • StatusACTIVE

What you can do with it

  • Map air pollutants — NO₂, aerosols, ozone
  • Track greenhouse gases and Earth's energy budget
  • Feed weather and air-quality analysis
Official description

The NOAA-20 Visible Infrared Imaging Radiometer Suite (VIIRS) Gross Primary Productivity (GPP) and Net Photosynthesis (PSN) Gap-Filled (VJ117A2GF) Version 2 data product is a cumulative composite of GPP values based on the radiation-use efficiency concept that is potentially used as inputs to data models to calculate terrestrial energy, carbon, water cycle processes, and biogeochemistry of vegetation. VJ117A2GF is an 8-day composite at 500 meter spatial resolution delivered as a gridded Level 4 (L4) product in Sinusoidal projection. The VJ117A2GF will be generated at the end of each year when the entire yearly 8-day VJ115A2H is available. Hence, the gap-filled VJ117A2GF is the improved VJ117A2, which has cleaned the poor-quality inputs from 8-day Leaf Area Index and Fraction of Photosynthetically Active Radiation (LAI/FPAR) based on the Quality Control (QC) label for every pixel. If any LAI/FPAR pixel did not meet the quality screening criteria, its value is determined through linear interpolation. However, users cannot get VJ117A2GF in near-real time because it will be generated only at the end of a given year. Provided in the VJ117A2GF product are variables for GPP, PSN, along with a quality control variable. A low resolution browse image for GPP is also available for each VJ117A2GF granule. 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

vj117a2gf_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="VJ117A2GF",
    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.