Opening Session II

The Sentinel-3 Surface Topography Mission (STM) is a key component of the Copernicus Sentinel-3 mission, set to revolutionise operational oceanography with a suite of advanced surface topography data products over ocean and sea-ice. In addition the STM will collect data over all earth surfaces providing improved monitoring of River and Lake stage heights and inputs to the development of Digital Elevation Models.

Sentinel-3 will be the first Earth Observation mission to provide 100% SAR altimetry coverage and LRM mode will be maintained as a backup-operating mode. In order to fully exploit the SAR capability, and validating the algorithms evolution, lower level data products (L1A, L1B and L1B-S) will be made available to the users, in addition to the level 2 products.

The processing algorithms developed for the Sentinel-3 Topography mission have been selected to meet the operational objectives of the Copernicus program and do benefit from 20 years of Altimetry experience gained with the ERS, Envisat, T/P, Jason & Cryosat missions. On top of the heritage processing algorithms, the S-3 Topography processing baseline includes more recent processing algorithm such as the SAMOSA SAR Ocean Retracker.

This paper provides an overview of the S-3 STM data products that will be generated operationally within the Sentinel-3 Payload Data Ground Segment (PDGS) by the Instrument Processing Facilities (IPFs), as well as an overview of the Sentinel-3 STM processing algorithms baseline.

 

Sentinel-3  is a key component of the Copernicus Program that will provide valuable data for Ocean, Land, Atmospheric and Climate applications. The Sentinel-3 mission will provide data continuity for the ERS, ENVISAT and SPOT-VGT missions.

Sentinel-3 will make use of multiple sensing instruments to accomplish its objectives; SLSTR (sea and Land Surface Temperature Radiometer), OLCI (Ocean and Land Colour Instrument), SRAL (SAR Altimeter), DORIS and MWR (Microwave Radiometer).

SLSTR and OLCI are optical instruments that will be used to provide data continuity for MERIS and AATSR instruments; the swath of the two instruments will overlap, leading to combined application and also allowing for the continuity of SPOT-VGT data (and PROBA-V).

 

The processing algorithms developed for the Sentinel-3  Optical mission have been selected to meet the operational objectives of the Copernicus program and do benefit from 20 years of experience gained with the ERS, ENVISAT and SPOT-VGT missions.

 

This paper provides an overview of the S-3 Optical data products that will be generated operationally within the Sentinel-3 Payload Data Ground Segment (PDGS) by the Instrument Processing Facilities (IPFs), as well as an overview of the Sentinel-3 Optical Sensors processing algorithms baseline.

The Sentinel-3 Mission Performance Framework has been established by ESA and EUMETSAT to ensure, over the mission lifetime, the required operability and adequacy of the core science products generated by the Payload Data Ground Segment (PDGS) and delivered to the Copernicus Services.

The Sentinel-3 Mission Performance Framework embraces ESA and EUMETSAT ‘in-house’ expertise and experts as well as the Mission Performance Centre (MPC) Team, the Sentinel-3 Validation Team (S3VT), the Copernicus POD service and CNES POD team.

The S-3 MPC will provide support to the Sentinel-3 project to ensure:

- The calibration and characterization of the S-3 sensors (A and B unit);

- The monitoring of the S-3 sensor performance (OLCI, SLSTR, SRAL, MWR);

- The products calibration;

- The validation of the S-3 core products using external and independent datasets (e.g. in-situ, numerical model or satellite data);

- The validation and verification of the S-3 core products using statistic and monitoring tools;

- The routine quality control of the S-3 core Land products generated by the Core Ground Station (CGS) and Land Processing Archiving Centre (PAC);

- The maintenance and evolution of the calibration, validation and processing algorithms;

The Copernicus Precise Orbit Determination (POD) Service is in charge of the operational provision of the orbit products for the ground processing. On top of this, the POD Service will perform long-term performance monitoring of the GNSS sensor, the quality control of the POD orbit products and platform attitude auxiliary data files with the support of POD and GNSS experts. Dedicated POD Quality Working Group meetings will be held for the Copernicus Sentinel-1, -2 and -3.

The S-3 Validation Team (S3VT) will provide support to the S-3 project in conducting field experiments and campaigns in support of Sentinel-3 Calibration and Validation.

The CNES French Agency will perform the long-term performance monitoring of the DORIS sensor on board S-3 satellites as well as the quality assessment of the orbit products they will generate.

Sentinel-3 Quality Working Groups (QWG) will be regularly convened  for the OLCI, SLST and Altimetry communities with  representation of the Mission Performance Framework partners, scientists and operational users. The S-3 QWG meetings, organized and co-chaired by ESA and EUMETSAT, will be the forum for discussing on the S-3 mission quality performance and recommending evolution of the S-3 Optical and Altimetry core products and processing algorithms baseline.

 

The ESA Data User Element (DUE) funded GlobCurrent project aims to improve satellite measurements of ocean surface currents through research and development activities and demonstrate their impact in scientific, operational and commercial applications.

A synergetic approach for quantitative analysis of high-resolution imaging spectrometer data, infrared radiometer data and radar altimeter data is followed and will take account of Sentinel-3 in combination with Sentinel-1 and other contributing missions. By use of complementary sensors from existing and past missions, this approach has often demonstrated that sharp gradients in the sea surface temperature (SST) field and the ocean surface chlorophyll-a distribution are spatially correlated with the sea surface roughness anomaly fields at scales in the sub-mesocale ranging from 1-10 km. Furthermore the surface slope at the mesoscale (30-50 km) derived from radar altimeter often depict the presence of larger scale eddies and meandering fronts in which these sub-mesoscale features are embedded.  To quantitatively interpret these multi-sensor data, the relationship to the sea surface current deformation field is explored in the intense frontal structures. As such the 2-dimensional structures seen in the satellite observations are evidence of upper ocean (~100 m) dynamics.  The possibly triggering mechanisms for these expressions include the interactions of the wind-driven upper layer with the quasi-geostrophic current field that, in turn, produces bands of downwelling (convergence) and upwelling (divergence).

The regular utilization of the sensor synergy from the combinations of Sentinel-3 and Sentinel-1 will provide a highly valuable data set for further research and development of the 2-dimensional surface expressions and their relationship to the upper ocean dynamics. This is expected to advance our understanding and as such it is also likely that the findings will have significant value for operational applications and marine services.

This presentation will shed more light on this using a variety of examples from a range of different current regimes and geographical areas.

This paper will explain the role of EUMETSAT in the Copernicus Programme and describe the EUMETSAT Sentinel-3 Marine Centre.

In the frame of the Copernicus programme, EUMETSAT and the European Union signed a Delegation Agreement covering the following activities:

Operation and maintenance of space segment for Sentinel-3, Sentinel-4 (instrument on-board MTG), Sentinel-5 (Instrument on-board EPS-SG), Sentinel-6 (Jason-CS satellite);

Ground Segment operation and provision of data and product services to the Marine, Atmosphere and Climate change services (Jason-3, Sentinel-3 marine, Sentinel-4, Sentinel-5 and Sentinel-6);

Maintenance and evolution of the related ground functions and infrastructure as a response to evolving user needs;

Provision of relevant data from EUMETSAT and Third Party missions related to the Marine, Atmosphere and Climate Change Services;

Support to the development, launch and LEOP of the recurrent satellites or instruments.

The first part of this paper will expand on those overall responsibilities and will provide examples.

The second part of this paper will focus on the Sentinel-3 marine centre operated by EUMETSAT. The architecture of the Sentinel-3 Marine centre is shown in Figure 1. An overview of the products and services delivered by the S3 marine centre will be given, focussing on the Marine Level 2 user products, which are unique to that centre. The presentation will explain the articulation of the Marine centre with other elements of the S3 ground segment, and the contribution of the EUMETSAT multi-mission elements for dissemination and archiving to the Marine Centre.