Earth Data School
About
Full catalog/VIIRSN_L3b_CHL
VIIRSN_L3b_CHL·v2022.0·dataset

Tiny ocean plants, chlorophyll (Suomi NPP)

Suomi-NPP VIIRS Level-3 Global Binned Chlorophyll (CHL) Data, version 2022.0
ocean NASA OB_CLOUD Level 3 active netCDF-4
In plain English

What it measures. The concentration of chlorophyll-a in surface seawater — the green pigment in tiny ocean plants (phytoplankton) — used as a stand-in for how much of this microscopic plant life is present.

How it's made. Produced as global gridded composites from the VIIRS instrument on the Suomi-NPP satellite using ocean color.

How & where you'd use it. Used to track phytoplankton over time, spot unusual blooms, and support fisheries and ecosystem studies; readings are less certain in cloudy coastal and inland waters.

What's measured

Oceans › Ocean Optics › Chlorophyll › Chlorophyll ConcentrationBIOSPHERE › VEGETATION › CHLOROPHYLLOCEANS › OCEAN CHEMISTRY › CHLOROPHYLLOCEANS › OCEAN CHEMISTRY › PIGMENTS › CHLOROPHYLLTERRESTRIAL HYDROSPHERE › WATER QUALITY/WATER CHEMISTRY › WATER CHARACTERISTICS › CHLOROPHYLL CONCENTRATIONSBIOSPHERE › ECOSYSTEMS › AQUATIC ECOSYSTEMS › PLANKTON › PHYTOPLANKTON

Coverage & cadence

  • Time span2012-01-02 → ongoing
  • Measured bySuomi-NPP (VIIRS)
  • 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 Chlorophyll-a data suite provides global, gridded composites of surface chlorophyll-a concentration (a proxy for phytoplankton biomass). CHL supports time-series and climatologies, anomaly detection, ecosystem and fisheries applications, and teaching/training, and pairs well with AVW, PAR, Kd(490), SST, and winds for environmental context. Note: retrievals in optically complex coastal/inland waters may carry higher uncertainty—refer to the mission/algorithm documentation (e.g., OCx/OCI) for details. Geophysical variables in this suite include: - chlor_a — Chlorophyll-a concentration (mg m⁻³)

Get the data

viirsn_l3b_chl_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="VIIRSN_L3b_CHL",
    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.