The main purpose of the SENTINEL-6 mission is to provide continuity of the satellite altimetry measurement (sea surface height) from the TOPEX/POSEIDON, JASON-1, JASON-2, and JASON-3 missions. The SENTINEL-6 mission is planned to continue and extend this measurement to create long time series with no degradation in precision and accuracy.
To fulfil the reference mission continuity (continuity of the JASON measurements) as well as to satisfy the needs of all the funding agencies, there are a number of high-level objectives, identified in this section. These are not mission requirements in themselves, but are the objectives that motivate the mission requirements.
SENTINEL-6 shall be an operational mission.
This objective means that the mission shall meet the requirements of the operational Copernicus marine information services and other weather and marine meteorology services.
This leads to requirements on:
SENTINEL-6 products shall be of sufficient quality to serve as the high precision reference mission in the CEOS virtual altimeter constellation.
High quality products are needed for operational applications and for research. Associated service requirements relate to measurement and product quality, particularly for the products generated after sufficient time has elapsed for the production of high-quality corrections. This includes requirements for extensive calibration and validation and involvement and support of the radar altimetry science community to the programme.
SENTINEL-6 products shall continue the long-term data series from TOPEX/POSEIDON, JASON-1, JASON-2, and JASON-3, to globally and regionally quantify and monitor sea level variability and the rate of sea level rise.
This objective leads to requirements on the content of the data products as well as on the continuity of the space-time sampling between missions. It also ensures the measurements over non-ocean surfaces as provided by JASON-2 and JASON-3. Long-term data series also exist for rivers and lakes. It is also an objective to also continue these series at least on a low resolution basis.
The SENTINEL-6 services shall provide products with contents enabling optimal combination with products from other altimeter missions for monitoring the broadest possible spectrum of ocean variability, including mesoscale features.
This objective is driven by important applications in operational oceanography in particular the initialization of operational ocean models. The optimum combination with SENTINEL-3 requires SAR mode capabilities of the SENTINEL-6 altimeter, as the SENTINEL-3 altimeter will be operated in SAR mode only.
SENTINEL-6 products shall contribute to marine meteorology by providing significant wave height and windspeed observations in near real-time.
This objective is a main motivation for a operational near real time service.
SENTINEL-6 products shall maintain their quality closer to the coastline than products from TOPEX/POSEIDON, JASON-1, JASON-2, and JASON-3.
This requires making use of new techniques in radar altimetry (e.g., high resolution or SAR mode) to improve the performance of the mission in coastal areas, i.e. the SAR mode also adopted for SENTINEL-3.
As a secondary mission, the radio occulation mission will not interfere with the compliance of any requirement of the primary mission.
SENTINEL-6 products shall provide bending angle and refractivity profiles from radio occultation observations to infer information on atmospheric temperature and humidity for weather and climate.
This takes advantage of the typical JASON orbit to deliver radio occultation with original time and space sampling.
Sentinel-6 Mission pages