Opening Session I

Copernicus is a joint initiative of the European Commission (EC) and European Space Agency (ESA), which aims at achieving an autonomous and operational Earth observation capacity. Copernicus marks the transition from R&D oriented efforts in earth observation towards operational services. The development of the space infrastructure i.e. the Copernicus “space component” for the provision of Earth remote sensing data, is led by ESA.  The atmosphere and ocean Sentinel Missions are being prepared in cooperation with EUMETSAT.

 

Sentinel-3 is an operational mission in high-inclination, low earth orbit for the provision of observational data to marine and land monitoring services. These services include the generation of sea, ice and land surface altimetry products, land and ocean colour products, sea and land surface temperature products, and vegetation products. The operational character of the mission implies a high level of availability of the data products and fast delivery time, which have been important design drivers for the mission.

 

The Sentinel-3 spacecraft accommodates a topography payload consisting of a SAR Radar Altimeter (SRAL) and a Microwave Radiometer (MWR) plus a suite of instruments for precise orbit determination (POD). In addition, two large optical instruments - the Ocean and Land Colour Instrument (OLCI) and the Sea and Land Surface Temperature Radiometer instrument (SLSTR). These instruments will ensure the continuation of important data streams established with ESA’s ERS and ENVISAT satellites. Full performance will be achieved with a constellation of two identical satellites, separated by 180 degrees in the same orbital plane.

 

Four Sentinel-3 satellites are in development with Sentinel-3A due for launch in late 2015 the Sentinel-3B satellite launch expected in 2017. Procurement of the C and D satellites is ongoing.  The overall service duration is planned to be 20 years and is expected to be fulfilled by a series of several satellites. Currently, the launch of the first Sentinel-3 satellite is planned in late 2015. This paper reports the current status of the Sentinel-3 Mission and pre-launch performance of the payload instruments.

1.         Introduction

The Copernicus Programme, being Europe’s Earth Observation and Monitoring Programme led by the European Union, aims to provide, on a sustainable basis, reliable and timely services related to environmental and security issues. The Copernicus Programme uses multiple source data and comprises a service component, a space infrastructure component and an in-situ component. The objective of the Copernicus Space Component (CSC) Programme is to fulfil the space-based observation requirements in response to European policy priorities with a particular emphasis on the Copernicus core services as identified by the Commission.  It aims at developing a fully operational capability in view of feeding Copernicus services with satellite data. The CSC Programme also aims at the operational provision of satellite data for other European and national services.  The main data source for the CSC Programme are the Sentinels, dedicated missions providing continuity to past or present data sets. In addition, the CSC Programme covers the development and operations of a Data Access Layer, the Coordinated Data System (CDS), aiming at providing Copernicus Services with satellite data from other than Sentinel missions (ESA, National, EUMETSAT and other Third Party Missions) of relevance to the overall space component of Copernicus.

2.         The Sentinel-3 mission

The Sentinel-3 mission forms part of the Copernicus Space Component. Its main objectives are to measure sea-surface topography, sea- and land-surface temperature and ocean- and land-surface colour in support of ocean forecasting systems, and for environmental and climate monitoring. The series of Sentinel-3 satellites will ensure global, frequent and near-real time ocean, ice and land monitoring, with the provision of observation data in routine, long term (up to 20 years of operations) and continuous fashion, with a consistent quality and a high level of reliability and availability.

The Sentinel-3 mission addresses these requirements by implementing and operating the following instruments, building on experience and heritage from the ERS and ENVISAT missions:

A dual frequency, delay-Doppler Synthetic Aperture Radar Altimeter (SRAL) instrument supported by a dual frequency passive microwave radiometer (MWR) for wet-tropospheric correction, a Precise Orbit Determination package including a GPS receiver, a DORIS instrument  and a laser retro-reflector for precise orbit determination. The combined topography package will provide exact measurements of sea-surface height, which are essential for ocean forecasting systems and climate monitoring. SRAL will also provide accurate topography measurements over sea ice, ice sheets, rivers and lakes.

A highly sensitive Ocean and Land Colour Imager (OLCI) delivering multi-channel wide-swath optical measurements for ocean and land surfaces. With 21 bands, compared to the 15 on Envisat’s MERIS, a design optimised to minimise sun-glint and, a resolution of 300 m over all surfaces, OLCI marks a new generation of measurements over the ocean and land. The swath of OCLI and nadir SLSTR fully overlap.

A dual-view Sea and Land Surface Temperature Radiometer (SLSTR) delivering accurate surface ocean, land, and ice temperature, with an accuracy better than 0.3 K. SLSTR measures in 9   spectral channels and two additional bands optimised for fire monitoring. SLSTR has a spatial resolution in the visible and shortwave infrared channels of 500 m and 1 km in the thermal infrared channels.

 Full performance will be achieved once both Sentinel-3A (launch foreseen for 3rd quarter 2015) and -3B will be in orbit, with a  revisit time of less than two days for OLCI and less than one day for SLSTR at the equator. The satellite orbit provides a 27-day repeat for the topography package, with a 4-day sub-cycle.

3.         Preparing for operations

On the space segment, platform and payload, final integration and tests are on-going for launch readiness towards the 3rd quarter of 2015.  The ground segment acquiring, processing and disseminating core data products in an operational context in the required timeliness to Copernicus, national users and other users is presently put in place.

 The Sentinel-3 missions will be jointly operated by ESA and EUMETSAT. ESA will be responsible for the operations, maintenance and evolution of the Sentinel-3 ground segment on land related products and EUMETSAT for the marine products. All facilities supporting the Sentinel-3 operations are in place:

Data acquisition and near real time (NRT) product generation, including data downlink and processing (NRT and offline) will be performed at Svalbard station,

Processing and Archiving Centres (PAC), which will perform the Sentinels’ systematic non-time-critical data processing, the on-the-fly data processing for specific cases and the reprocessing in case of processing algorithms or calibration parameters upgrades:

OLCI processing and archiving will be performed at DLR,

SRAL processing and archiving will be performed at CLS,

SLSTR and S-3 synergy products processing and archiving will be performed by ACRI,

EUMETSAT’s marine centre acts as PAC for marine products.

Missions Performance Centre (MPC): Operational Quality Control, Expert Support Laboratories (ESL), Calibration and Validation

4.         Data products

The Sentinel-3 ground segment systematically acquires, processes and distributes a set of pre-defined core data products to the users. For a detailed description of the core data products please see https://earth.esa.int/web/sentinel/missions/sentinel-3/data-products. On request from the European Commission ESA and EUMETSAT are presently assessing the possibility to include further data products, in particular on aerosol optical depth, fire monitoring and synergistic products over land.

5.         Focus of this paper

This paper will provide an update on the status of the development of the space and ground segment for the Sentinel-3 mission, including an overview and available data products and data access mechanisms.

Copernicus is the new name of the European Earth Observation Programme, GMES (Global Monitoring for Environment and Security). Copernicus or rather its predecessor was established as an EU programme. It covers all the activities for ensuring an uninterrupted provision of accurate and reliable data and information on environmental issues and security matters to users in charge of policy making, implementation and monitoring, in the EU and its Member States. Copernicus aims at providing Europe with a continuous, independent and reliable access to observation data and information. The EU investment aims at filling the observation gaps, providing access to existing assets and developing operational services. The data policy of the Copernicus programme supports an open, full and free of charge data access that is in line with the data sharing principles of the Group for Earth Observation (GEO).

The presentation will focus on the role of Sentinel-3 in the Copernicus Programme, the funding, governance, data dissemination and user requirements.

Copernicus is the most ambitious, most comprehensive Earth observation system world-wide. It aims at giving decision-makers better information to act upon, at global, continental, national and regional level.

The European Union (EU) leads the overall programme, while the European Space Agency (ESA) coordinates the space component. Similar to meteorology, satellite data is combined with data from airborne and ground sensors to provide a holistic view of the state of the planet. All these data are fed into a range of thematic information services designed to benefit the environment and to support policy-makers and other stakeholders to make decisions, coordinate policy areas, and formulate strategies relating to the environment. Moreover, the data will also be used for predicting future climate trends.

The first dedicated Copernicus satellite mission, a radar imaging mission called Sentinel-1A, was successfully launched on 3^rd April 2014. The next mission (first unit of the optical imager, Sentinel-2) will be launched in June this year. The remaining Sentinels will be launched within the next years and will be progressively covering all domains of Earth Observation.

In particular, Sentinel-3, will be launched at the end of this year. With a suite of instruments on board Sentinel-3 will measure sea-surface topography, sea- and land-surface temperature and ocean- and land-surface colour with high-end accuracy and reliability in support of ocean forecasting systems, and for environmental and climate monitoring.

As more data are made available, better decisions can be made, more business can be created and science and research can be achieved through the upcoming Sentinel data.

SEOM is a programme element within the fourth period (2013-2017) of ESA’s Earth Observation Envelope Programme (http://seom.esa.int/). The prime objective is to federate, support and expand the international research community that the ERS, ENVISAT and the Envelope programmes have built up over the last 25 years. It aims to further strengthen the leadership of the European Earth Observation research community by enabling them to extensively exploit future European operational EO missions. SEOM is enabling the science community to address new scientific research that are opened by free and open access to data from operational EO missions.

Based on community-wide recommendations for actions on key research issues, gathered through a series of international thematic workshops and scientific user consultation meetings, a work plan has been established and is approved every year by ESA Members States. The 2015 SEOM work plan is covering the organization of three Science users consultation workshops for Sentinel-1/3/5P, the launch of new R&D studies for scientific exploitation of the Sentinels, the development of open-source multi-mission scientific toolboxes, the organization of advanced international training courses, summer schools and educational materials, as well as activities for promoting the scientific use of EO data.

The first SEOM projects have been tendered since 2013 including in particular the development of Sentinel-3 (imaging) toolboxes released end September 2014 , the S3 SAR Altimetry toolbox to be started early 2015, the S3 for science Ocean color studies, the S3 for science SAR Altimetry studies as well as studies for exploiting the synergy between the Sentinels for land and ocean scientific exploitation. The status and first results from these SEOM projects will be presented and an outlook for upcoming SEOM studies and upcoming Land and Ocean advanced training opportunities for young scientists will be given.

Finally the trend for future EO scientific exploitation using state of the art tools and technology called EO Science 2.0 will be introduced and upcoming ESA EO Science 2.0 users consultation in preparation for EOEP5 will be presented.

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