Sentinel-3 is a dedicated Copernicus satellite mission delivering a variety of high-quality ocean measurements.

The mission's main objective in support to the Marine Environment is to determine parameters such as sea-surface topography, sea-surface temperature and ocean-surface colour. It provides two day global coverage optical data (with two satellites), as well as altimetry measurements, for sea and land applications with real-time products delivered in less than three hours. The satellites are operationally managed from the EUMETSAT Sentinel-3 Marine Centre.


Why the Sentinel-3 mission?


1. Builds on heritage of previous ocean observing satellites (e.g. ENVISAT) for continuity of measurements.
2. Constellation of satellites will provide long-term operational measurements of the ocean colour, temperature, and sea surface topography over the global ocean every two days.
3. Improved combination of spatial, temporal and spectral resolution, and better radiometric sensitivity allows for measurements of ocean colour from coastal to open ocean environments.
4. Advanced dual view sensor for atmospheric correction and retrieval of sea surface temperature.
5. High-resolution SAR mode altimetry for improved performance in the coastal domain and analysis of fine-scale ocean features.
6. Data is delivered direct to users and to downstream Copernicus Services.

Altimetry Services
Ocean Colour Services
Sea Surface Temperature Services

How does it work?

Illustration of MTG satellite

Each Sentinel-3 satellite carries the Ocean and Land Colour Imager (OLCI), the Sea and Land Surface Temperature Radiometer (SLSTR) and the Synthetic Aperture Radar Altimeter (SRAL). SRAL is supported by the Precise Orbital Determination (POD) module, and Microwave Radiometer (MWR).

Further details on the instruments on board the Sentinel-3 satellites, including their capability:

Further details on the Sentinel-3 Ground Segment

What data is available?


OLCI provides visible and near infrared radiances in 21 spectral bands and derived geophysical products, including chlorophyll and suspended matter.

SLSTR provides VNIR and SWIR radiance across six solar reflectance bands and brightness temperatures across three thermal IR bands, as well as sea surface temperature in both nadir and dual view configurations.

OLCI and SLSTR provide global coverage with a revisit time of two days with two sensors.

SRAL provides waveform echoes in PLRM and SAR modes, as well as sea surface height, significant wave height and surface wind speed measurements. SRAL has a nadir revisit interval of 27 days.

OLCI data
SLSTR data
SRAL data

How do I get the data, and in what format?


EUMETSAT provides data access through a number of routes, depending on preferred delivery mode and latency of the data.

1. Recently acquired data can be accessed via Copernicus Online Data Access (CODA).
2. Reprocessed data can be accessed via Copernicus Online Data Access Reprocessed (CODAREP)
3. Older data can be downloaded via the EUMETSAT Data Centre.
4. NRT Sentinel-3 data can be accessed via  EUMETCast.
5. Data is also available through the Copernicus WeKEO hosted processing system.

Data from Sentinel-3 are delivered as a Standard Archive Format for Europe (SAFE) product package containing a collection of files.

More on Sentinel-3 Data Formats

How can I learn about Sentinel-3 capabilities?

Graphic of international geostationary satellites

Sentinel-3 applications are showcased in the EUMETSAT Case Studies.

Guidance on working with the Copernicus data available from EUMETSAT can be found in the online learning material on the EUMETSAT YouTube channel.

Feedback on data validation and product development are welcomed through the Sentinel-3 Validation Team 

Questions about Sentinel-3 marine data can be directed to our User Service Helpdesk or the Copernicus Marine User Forum.

Sentinel-3 tools and training

Are there similar instruments to those on Sentinel-3?

  • The OLCI and SLSTR instruments on Sentinel-3 represent evolutions of MERIS and AATSR instruments aboard ENVISAT
  • SRAL uses SAR mode altimetry approaches similar to those on the CryoSat satellite series.
  • Sea surface topography measurements from SRAL can also be compared with those from the Jason altimeters.
  • The ocean colour data produced by OLCI are similar to those provided by MODIS and VIIRS.
  • Thermal radiometry products from SLSTR have corollaries with those from AVHRR sensors operated in part by EUMETSAT aboard Metop.

Launch dates

Satellite Launch date Details
Sentinel-3A 16 February 2016 Altimetry
Ocean colour
Surface thermal radiometry
Sentinel-3B 25 April 2018 Altimetry
Ocean colour
Surface thermal radiometry
Sentinel-3C Planned for 2021 Altimetry
Ocean colour
Surface thermal radiometry
Sentinel-3D Post-2021 Altimetry
Ocean colour
Surface thermal radiometry

Sentinel-3 in operations

Sentinel-3A and 3B are in full operational status.

Information on product quality can be found via the Monitoring & Evaluation of Thematic Information from Space (METIS) service.

Service status updates can be obtained from the User Notification Service and other sources, see the Status Service page for full details.

Latest updates from Sentinel-3 Ocean Colour Validation Team Meetings are provided on the EUMETSAT marine user forum.

Sentinel-3 documentation

Further reading on the requirements, product algorithm baselines and other mission can be found in the Copernicus section of the Technical Documents page.

Mission Facts

  • The Sentinel-3 mission is part of the European Commission Copernicus programme for Earth Observation.
  • The satellites will provide land and ocean data, with the land data delivered by ESA, while EUMETSAT will be responsible for both the operation of the satellite and the processing and delivery of ocean data.
  • The first two satellites (A and B) were initially operated in a temporary tandem phase to allow for instrument intercomparison.
  • OLCI Ocean colour data full resolution (300m) data is available globally.
  • Sea surface temperature data from SLSTR is available at 1 km resolution.
  • Along track altimetry is available at 300m resolution, at 1 Hz and 20 Hz frequency in SAR mode.
  • Multiple atmospheric correction methods and algorithms provide both open ocean and complex water products derived from the OLCI ocean colour reflectance data.
  • Overlap between SLSTR and OLCI swaths allows for synergistic product use.
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