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Full catalog/MODIST_L3m_PAR
MODIST_L3m_PAR·v2022.0·dataset

Sunlight available to ocean plants (Terra MODIS)

Terra MODIS Level-3 Global Mapped Photosynthetically Available Radiation (PAR) Data, version 2022.0
ocean NASA OB_CLOUD Level 3 active netCDF-4
In plain English

What it measures. How much usable sunlight in the colors plants use for photosynthesis reaches the ocean surface, given as a daily amount of light energy per area.

How it's made. Estimated from the Terra satellite's MODIS instrument and mapped into a global gridded product.

How & where you'd use it. Helps scientists estimate how much ocean plant life (phytoplankton) is growing, interpret algae blooms, and feed marine ecosystem models; also used in education about how light shapes ocean biology.

What's measured

Oceans › Ocean Optics › Photosynthetically Active Radiation

Coverage & cadence

  • Time span2000-02-24 → ongoing
  • Measured byTerra (MODIS)
  • Processing levelLevel 3
  • Spatial extent-180, -90, 180, 90
  • FormatsnetCDF-4
  • StatusACTIVE

What you can do with it

  • Watch sea-surface temperature and marine heatwaves
  • Spot algal blooms and ocean-colour shifts
  • Support fisheries and coastal monitoring
Official description

The Photosynthetically Available Radiation (PAR) data suite provides satellite-based estimates of the downwelling solar radiation in the 400–700 nm range that is available for photosynthesis at the ocean surface. These products quantify the daily or instantaneous amount of usable light energy, expressed in moles of photons m⁻² (commonly noted as “Einstein m⁻²”), and are widely used to estimate marine primary production, interpret phytoplankton bloom dynamics, provide context for optical and biogeochemical measurements,and support ecosystem models and education on light–biology interactions. Geophysical variables in this suite include: - par — Daily photosynthetically available radiation (mol photons m⁻² d⁻¹)

Get the data

modist_l3m_par_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="MODIST_L3m_PAR",
    version="2022.0",
    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 OB_CLOUD
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.