Sunlight at top of atmosphere, coarse (Sentinel-3B OLCI)
What it measures. Coarse-resolution measurements of sunlight reflected back to space at the top of the atmosphere, recorded by the OLCI instrument in 21 color bands across all of Earth's surfaces. Each file holds the calibrated light readings plus details on viewing angle and quality flags.
How it's made. Generated from the OLCI imaging spectrometer aboard Europe's Sentinel-3B satellite, calibrated and mapped onto an even grid as a Level-1B product.
How & where you'd use it. A building-block input used to derive ocean color, land, and atmosphere products; most people use it through those higher-level products rather than directly.
What's measured
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 Reduced Resolution Top of Atmosphere Reflectance product, S3B_OL_1_ERR is generated from the data acquired 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_ERR 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) consist of 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 on illumination and observation geometry, environment 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 Time_coordinates.nc Time stamp annotations Geo_coordinates.nc High resolution georeferencing data Quality_flags.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
import earthaccess
earthaccess.login(strategy="netrc") # free Earthdata Login
results = earthaccess.search_data(
short_name="S3B_OL_1_ERR",
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 LAADSBrowsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.