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Full catalog/OLCIS3A_L3m_ERR_RRS
OLCIS3A_L3m_ERR_RRS·v2022.0·dataset

How much light the ocean reflects back (Sentinel-3A, reduced res)

Sentinel-3A OLCI Level-3 Global Mapped Earth-observation Reduced Resolution (ERR) Remote-Sensing Reflectance (RRS) Data, version 2022.0
ocean NASA OB_CLOUD Level 3 active netCDF-4
In plain English

What it measures. How much light the ocean reflects back at different wavelengths, the basic measurement of ocean color, mapped globally at reduced resolution.

How it's made. Derived from the OLCI instrument on the Sentinel-3A satellite, processed into mapped composites at a coarser resolution.

How & where you'd use it. This reflectance is the foundational ingredient for deriving chlorophyll, water clarity, and other ocean products, and for developing and checking ocean-color algorithms. Coastal and inland waters carry more uncertainty.

What's measured

Oceans › Ocean Optics › Reflectance

Coverage & cadence

  • Time span2016-04-05 → ongoing
  • Measured bySentinel-3A (OLCI)
  • 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 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. This activity was informed by the Satellite Needs Working Group (SNWG), an interagency effort of the U.S. Government dedicated to identifying and addressing Earth observation needs across U.S. civilian federal agencies. Geophysical variables in this suite include: - Rrs — Remote sensing reflectance (sr⁻¹)

Get the data

olcis3a_l3m_err_rrs_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="OLCIS3A_L3m_ERR_RRS",
    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.