Sentinel-6

Continuing high precision ocean altimetry measurements

The Copernicus Sentinel-6 Michael Freilich satellite involves two key missions: radar altimetry and radio occultation. The radar altimeter mission provides high-precision measurements of global sea-level.

Last Updated

21 February 2023

Published on

19 May 2020

A second objective is to collect high resolution vertical profiles of temperature, using the GNSS Radio-Occultation sounding technique, to assess temperature changes in the troposphere and stratosphere, and to support numerical weather prediction (NWP).

Continuing the long-term record of data built by a heritage of instruments from the TOPEX/Poseidon and Jason series of satellites, the Sentinel-3 altimetry missions.
Measurements of ocean topography enable numerical prediction of the three-dimensional ocean, which is a prerequisite for the development of operational oceanography and improvements to monthly and seasonal weather forecasts.
Variations of sea level in our changing climate (some mm per year) can only be monitored on a global scale by High Precision Ocean Altimetry (HPOA) observations. Altimetry measurements are also essential to understand how the ocean stores and redistributes heat, water and carbon in the climate system.
The NASA GNSS Radio Occultation mission observes vertical profiles of temperature and water vapour in the atmosphere. The orbit of the Sentinel-6 mission provides a unique opportunity to improve coverage of radio occultation observations.

Satellite	Launch date	Details
Sentinel-6A Michael Freilich	21 November 2020	Altimetry Radio Occultation
Sentinel-6B	Planned for 2025	Altimetry Radio Occultation

Sentinel-6 is part of the European Commission Copernicus programme, and a collaborative mission implemented and co-funded by the European Commission, the European Space Agency, EUMETSAT and the US, through NASA and the National Oceanic and Atmospheric Administration.
The Copernicus Sentinel-6 mission extends the unique climate record initiated in 1992 by the TOPEX/Poseidon mission (1992–2006,) and continued by Jason (2001–2013), Jason-2 (2008–2019) and Jason-3 (2016).
The Sentinel-6 satellites also carry a NASA GNSS radio-occultation instrument, providing observations of vertical profiles of temperature and moisture in the troposphere and stratosphere.
NASA provides the microwave radiometer and GNSS radio occultation instrument, and the launch services for the two Sentinel-6 satellites.
EUMETSAT has developed and operates most of the Copernicus Sentinel-6 ground segment, based on the reuse of some existing assets.
ESA/ESOC performed the Copernicus Sentinel-6 launch and early operations phases (LEOP).

Main products, key variables and applications

	Products	Main variables	Main applications
Near Real Time (NRT)	Operational Geophysical Data Record (OGDR)	Significant Wave Height (SWH) Surface Wind Speed (WIND) Sea Surface Height (SSH) Information on humidity and temperature profiles (RO)	Real time operational oceanography Marine nowcasting Operational wave forecasting Numerical weather prediction
Short Time Critical (STC)	Interim Geophysical Data Record (IGDR)	Same altimetry products as above plus Absolute Dynamic Topography (ADT) Ocean Geostrophic Velocities More accurate Sea Surface Height (SSH)	Operational oceanography Seasonal Forecasting
Non Time Critical (NTC)	Geophysical Data Record (GDR)	Same altimetry products as above Most accurate Sea Surface Height (SSH) Most accurate information on humidity and temperature profiles (RO)	Sea level monitoring Climate monitoring Climate research

Sentinel-6 instruments and ground segment

Sentinel-6 altimetry instruments

Six instruments are used for the Sentinel-6 altimetry mission.

Sentinel-6 radio occultation instrument

Global Navigation Satellite System Radio Occultation (GNSS-RO) on Copernicus Sentinel-6.

Sentinel-6 ground segment

The Sentinel-6 ground segment reflects the international collaboration that underpins the mission.

Waves breaking on sea wall. Credit: Zacarias da Mata

Altimetry services

Altimetry data is used to determine sea level height, wind speed and wave height.

Sea level variations measured by S6 and Copernicus satellites

Altimetry resources

Documents relating to altimetry services (SRAL/MWR, Poseidon-4/AMR-c and Jason missions, including Algorithm Theoretical Basis Documents, Product Data Format Specification, Product Notices and any other technical reports.