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Full catalog/S3B_OL_1_EFR
S3B_OL_1_EFR·v1·dataset

Raw light at the top of the atmosphere (Sentinel-3B)

OLCI/Sentinel-3B L1 Full Resolution Top of Atmosphere Reflectance
land NASA LAADS Level 1B active netCDF-4
In plain English

What it measures. Raw measurements of sunlight reflected back from the top of the atmosphere across 21 color bands, before any correction for atmospheric effects.

How it's made. Generated from the OLCI imaging spectrometer on Sentinel-3B, calibrated to physical units and snapped onto an evenly spaced Earth grid as a Level-1B product.

How & where you'd use it. A building-block input: scientists run it through further processing to get true surface color, ocean color, and other products rather than using these top-of-atmosphere numbers directly.

What's measured

SPECTRAL/ENGINEERING › INFRARED WAVELENGTHS › REFLECTED INFRAREDSPECTRAL/ENGINEERING › PLATFORM CHARACTERISTICSSPECTRAL/ENGINEERING › PLATFORM CHARACTERISTICS › ATTITUDE CHARACTERISTICSSPECTRAL/ENGINEERING › VISIBLE WAVELENGTHS › VISIBLE RADIANCEATMOSPHERE › ATMOSPHERIC RADIATION › REFLECTANCE

Coverage & cadence

  • Time span2018-05-14 → ongoing
  • Measured bySentinel-3B (OLCI)
  • Processing levelLevel 1B
  • Spatial extent-180, -90, 180, 90
  • FormatsnetCDF-4
  • StatusACTIVE

What you can do with it

  • Track deforestation, fire scars and land-cover change
  • Monitor crop and vegetation health (NDVI/EVI)
  • Map how built-up vs. green an area is over time
Official description

The OLCI/Sentinel-3B L1 Full Resolution Top of Atmosphere Reflectance product, S3B_OL_1_EFR is generated from the data aquired by the Ocean and Land Colour Instrument (OLCI) on board European Earth Observation satellite mission, SENTINEL-3. The OLCI is a push-broom imaging spectrometer that measures solar radiation reflected by the Earth at a ground spatial resolution of around 300m, over all surfaces, in 21 spectral bands. OLCI is based on the imaging design of ENVISAT's Medium Resolution Imaging Spectrometer (MERIS). It has a 1270km wide swath. For more information about the instrument and the mission, visit [Sentinel Online](https://sentinel.esa.int/web/sentinel/home). The S3B_OL_1_EFR is a Level-1B product. This is composed of an information package map, called a manifest, 22 measurement data files, and seven annotation data files. The 21 measurement data files (one for each band) for Top Of Atmosphere (TOA) radiances, calibrated to geophysical units (W.m-2. sr-1 Micro meter-1), georeferenced onto the Earth's surface, and spatially resampled onto an evenly spaced grid. Seven annotation files provide information pertaining to illumination and observation geometry, environmental data (meteorological data), and quality and classification flags. Both measurement data files and annotation data files are written in netCDF 4 format. The manifest file is in XML format and contains metadata associated with the instrument and the processing. The S3A_OL_1_EFR is generated in Earth Observation (EO) processing mode and all parameters in this product are provided for each re-gridded pixel on the product image and for each removed pixel. The OL_1_EFR product package is described below: Element name Description xfdumanifest.xml SENTINEL-SAFE product manifest Oa##_radiance.nc Radiance for OLCI acquisition bands 01 to 21 removed_pixels.nc Removed pixels information needed for Level-1C generation time_coordinates.nc Time stamp annotations geo_coordinates.nc High resolution georeferencing data qualityFlags.nc Classification and quality flags tie_geo_coordinates.nc Low resolution georeferencing data tie_geometries.nc Sun and view angles tie_meteo.nc ECMWF meteorology data instrument_data.nc Instrument data note: Oa## represents all the OLCI channels (Oa1 to Oa21). For more information about the product, read the SENTINEL-3 OLCI [User Guide](https://sentinel.esa.int/web/sentinel/user-guides/sentinel-3-olci).

Get the data

s3b_ol_1_efr_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="S3B_OL_1_EFR",
    version="1",
    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 LAADS
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.