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Full catalog/VIIRSJ1_L3m_RRS_NRT
VIIRSJ1_L3m_RRS_NRT·v2022.0·dataset

Color of the ocean surface (NOAA-20, near-real-time)

NOAA-20 VIIRS Level-3 Global Mapped Remote-Sensing Reflectance (RRS) - Near Real-time (NRT) Data, version 2022.0
ocean NASA OB_CLOUD Level 3 active netCDF-4
In plain English

What it measures. The color of the ocean surface, captured as how much light of each wavelength leaves the water relative to the sunlight coming in.

How it's made. Produced from the VIIRS instrument on the NOAA-20 satellite as a near-real-time global mapped product, using readily available supporting data so it can be delivered quickly.

How & where you'd use it. This ocean-color measurement is the starting point for tracking things like phytoplankton, water clarity, and water quality; the near-real-time version trades some accuracy for speed.

What's measured

Oceans › Ocean Optics › Reflectance

Coverage & cadence

  • Time span2017-11-29 → ongoing
  • Measured byNOAA-20 (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 Ocean Biology DAAC produces near real-time (NRT) products using the best-available combination of ancillary data from meteorological and ozone data. As such, the inputs and the calibration used are less than optimal. Near real-time products provide a snapshot of the data during a short time period within a single orbit. The Remote Sensing Reflectance (RRS) suite provides the remote sensing reflectance at wavelength λ (nm)—the ratio of water-leaving radiance to downwelling irradiance just above the surface (units sr⁻¹). Variables are named by their band center (e.g., Rrs_412, Rrs_443). Rrs_λ is the foundational observable used to retrieve products such as chlor_a, Kd_490, IOPs, and to support algorithm development, validation, water-quality, and ecosystem applications. Users should review per-file quality flags (e.g., land, cloud, sun glint, high aerosol) and mission documentation—especially in optically complex coastal/inland waters. Geophysical variables in this suite include: - Rrs — Remote sensing reflectance (sr⁻¹)

Get the data

viirsj1_l3m_rrs_nrt_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="VIIRSJ1_L3m_RRS_NRT",
    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.