Sentinel-2

Copernicus is a joint initiative of the European Commission (EC) and the European Space Agency (ESA), designed to establish a European capacity for the provision and use of operational monitoring information for environment and security applications.

Within  the Copernicus programme, ESA is responsible for the development of the Space Component, a  fully operational space-based capability to supply earth-observation  data  to  sustain  environmental  information  Services in Europe. The Sentinel  missions are Copernicus dedicated Earth Observation missions composing the  essential  elements  of  the  Space  Component. In the global Copernicus framework,  they  are  complemented  by  other  satellites  made available  by  third-parties or by ESA and coordinated in the synergistic system through the Copernicus  Data-Access system versus the Copernicus Services.

The Copernicus Sentinel-2 mission provides continuity to services relying on multi spectral high-resolution optical observations over global terrestrial surfaces. Sentinel-2 will capitalize on the technology and the vast experience acquired in Europe and the US to sustain the operational supply of data for services such as forest monitoring, land cover changes detection or natural disasters management.

The Sentinel-2  mission offers an unprecedented combination of the following capabilities:
   ○    Systematic global coverage of land surfaces: from 56°South to 84°North,
      coastal waters and Mediterranean sea;
   ○    High revisit: every 5 days at equator under the same viewing conditions
      with 2 satellites;
   ○    High spatial resolution: 10m, 20m and 60m;
   ○    Multi-spectral information with 13 bands in the visible, near infra-red
      and short wave infra-red part of the spectrum;
   ○    Wide field of view: 290 km.

The  data from the Sentinel-2 mission are available openly and freely for all users with online easy access since December 2015. The presentation will give a  status  report  on  the  Sentinel-2 mission, and outlook for the remaining ramp-up  Phase,  the  completion  of  the constellation and a view to ongoing evolutions.

In the frame of the Copernicus programme lead by the European Commission, the European Space Agency (ESA) is developing the Sentinel-2 optical imaging mission devoted to the operational monitoring of land and coastal areas.

The Sentinel-2 mission is based on a two-satellite constellation deployed in polar sun-synchronous orbit. Sentinel-2 will offer a unique combination of global coverage with a wide field of view (290km), a high revisit (5 days with two satellites), a high resolution (10m, 20m and 60m) and multi-spectral imagery (13 spectral bands in visible and shortwave infra-red domains).

This presentation provides an overview of Sentinel-2 mission in-flight measured performances plus an overview of all the activities related to data quality (calibration, validation, L1 and L2A products qualification) being carried by ESA and its partners.

An overview on all mission performances with respect to key mission requirements is given, with a focus on the most critical ones for user applications such as the radiometric signal-to-noise ratio, the absolute geolocation, or the multi-temporal registration between products (a zoom on the generation of the Global Reference Image, GRI, by the Mission Performance Centre, MPC, team).

The Sentinel-2 Copernicus mission will bring significant breakthrough in the exploitation of space borne optical data. Sentinel-2 time series will transform land cover, agriculture, forestry, in-land water and costal EO applications from mapping to monitoring, from snapshot to time series data analysis, from image-based to pixel-based processing. The 5-days temporal revisiting of the Sentinel-2 satellites, when both units will be operated together, will usher us in a new era for time series analysis at high spatial resolutions (HR) of 10-20 meters. The monitoring of seasonal variations and processes in phenology and hydrology are examples of the many R&D areas to be studied. The mission’s large swath and systematic acquisitions will further support unprecedented coverage at the national scale addressing information requirements of national to regional policies.

Within ESA programs, such as the Data User Element (DUE), Scientific Exploitation of Operational Missions (SEOM) and Climate Change Initiative (CCI), several R&D activities are preparing the exploitation of the Sentinel-2 mission towards reliable measurements and monitoring of e.g. Essential Climate Variables and indicators for the Sustainable Development Goals. Early Sentinel-2 results will be presented related to a range of applications and scientific domains such as agricultural monitoring at national scale (DUE Sen2Agri), wetland extent and condition over African Ramsar sites (DUE GlobWetland-Africa), land cover mapping for climate change (CCI Land Cover), national land monitoring (Cadaster-Env), forest degradation (DUE ForMoSa), urban mapping (DUE EO4Urban), in-land water quality (DUE SPONGE), map of Mediterranean aquaculture (DUE SMART) and coral reef habitat mapping (SEOM S2-4Sci Coral). The above-mentioned activities are only a few examples from the very active international land imaging community building on the long-term Landsat and Spot heritage and knowledge.

The Sentinel-2 PDGS ensures the data acquisition, processing, archiving and
dissemination of the Sentinel-2 MSI data to the final users. In addition, it
is responsible for performing conflict-free mission planning according to a
pre-defined operational scenario, and ensures the quality of data products
and performance of the space-borne sensors by continuous monitoring,
calibration and validation activities, guaranteeing the overall performance
of the mission. the presentation will give an overview of the payload data
ground segment operational performance, and an outlook for the finalisation
of the S2A ramp-up Phase, towards inclusion of the S2B satellite.

This presentation will resume the activity of CNES during the In Orbit Calibration Phase of Sentinel 2A as well as the transfer of production of GIPP (Ground Image Processing Parameters) from CNES to ESRIN.  The state of the main calibration parameters and performances, few months before PDGS is declared fully operational, will be listed and explained.

In radiometry a special attention will be paid to the absolute calibration using the on-board diffuser, and the vicarious calibration methods using instrumented or statistically well characterized sites and inter-comparisons with other sensors.  Regarding geometry, the presentation will focus on the performances of absolute location with and without reference points.  The requirements of multi-band and multi-temporal registration, of a significant importance for the continuation of mission, will be exposed. Finally, the construction and the rule of the GRI in the future will be explained.  The presentation will end with the perspective of the mission, according to the present measured observations.