Figure 1- Variability of ocean level as of October 16th, 1997
This map showing the El Niño phenomenon has been produced in the scope of the DUACS project from altimetric observations of TOPEX/POSEIDON and ERS satellites
(http://www.cls.fr/duacs/)
The CLS Company is one of MEDIAS-FRANCE founder members. This Company is one of the world leading operators of satellite-based systems for location, data collection and remote sensing. Its various and privileged application fields includes the study and monitoring of our environment. Its wide range of skills and activities enable CLS to offer global solutions which integrate requirement analysis, data processing, value-added services, consultancy and engineering. CLS engineers and technicians have gained a high reputation, confirmed by many international partnerships.
Everywhere in the world, CLS offers to scientists and industrials complementary systems and associated know-how in the field of location, satellite altimetry and orbitography.
CLS three main skills include:
- operation of satellite-based systems designed for location, data collection and remote sensing (Argos, Doris and satellite altimetry);
- studies, training and engineering related to these systems;
- promotion, distribution and marketing of derived products and services.
CLS distributes observation data to its users. These results may be accessed through a mere connection to CLS servers, or may be automatically sent upon request.
To meet its customers' needs, CLS is also orienting its services towards the marketing of ready for use turnkey solutions, such as: maps of ocean circulation, tracking of fishing vessels, design of operational data processing centres.
To keep in line with the leading theme of this current issue of "MEDIAS Newsletter", we will mainly present the activities of this company in the field of space oceanography.
The part played by oceans in the evolution of the climate and of the terrestrial environment is one of the big issues faced by men. Sea measurements (ships, drifting or moored buoys...) enable a very accurate but only local observation of oceans. Satellites have a much larger vision of the Earth and deliver continuously high-quality homogeneous measurements. In this context, the altimetry technique has reached its maturity. This technique of satellite-based observation enables to measure the ocean level (see Y. Menard's article in this issue).
The first satellite observations of sea level (the so-called "altimetric measurements") date back to the end of the 1970s. At the beginning of the 1990s, satellites began to follow one another with the aim to transmit regularly such data covering the whole oceans.
This regular, homogeneous and very accurate vision of the oceans has improved the understanding of ocean dynamics and aroused the keenest interest from the oceanographic community. For the first time, and for several years, it has been possible to monitor economically and socially important climatic phenomena, such as El Niño.
This regular monitoring has also strengthened the idea that satellite measurements, sea measurements and numerical models should be associated in order to observe, understand and forecast ocean behaviour. This is why large observation programmes have been gradually implemented, such as WOCE (World Ocean Circulation Experiment, 1990-2002) and GODAE (Global Ocean Data Assimilation Experiment, 2003-2005). These programmes involve many national and international organisations.
The future JASON and ENVISAT satellites will benefit from the wide experience and know-how gained during the previous missions and will be more particularly dedicated to operational altimetry
CLS is the world operator of satellite-based location and data collection systems. In January 1990, this company set up a team dedicated to space oceanography, including 5 engineers and oceanographers. Within 10 years, and thanks to the support of its main French customers (CNES French Space Agency, and SHOM Hydrography and Oceanography Department of the French Navy), the members of this team have participated in the development of the ground segments and oceanographic applications of all the franco-american and European altimetric missions, from ERS-1 to ENVISAT, including TOPEX-POSEIDON, ERS-2 and JASON-1. About thirty persons are currently working in the CLS Space Oceanography Division.
The following subjects are part of the main themes of the oceanography studies which are led within the CLS Space Oceanography Division:
- observation and understanding of ocean circulation;
- monitoring of the mean ocean level;
- observation and forecasting of the El Niño phenomenon (please refer to the articles dedicated to this subject in this issue);
Because CLS is present and active at every stage of the production line of satellite-based oceanography data, this company has acquired within ten years a unique know-how, from the development of ground segments to oceanographic applications, including management and data processing:
- instrument expertise and telemetry processing;
- calibration and operational validation of altimetric measurements;
>br> - inter-calibration of data from different satellites;
- data interpretation, scientific and operational spin-off;
- data processing, management and circulation (AVISO, DUACS, MFSPP);
- oceanographic studies integrating observations from various origins (satellite measurements and sea measurements): AGORA, CANIGO, DIADEM, DUACS, GANES, MATER, MFSPP, OPERALT;
- participation in the development of operational oceanography systems (SOPRANE, SOAP, MERCATOR).
- study and protection of the Mediterranean (major centre of interest for the Medias network);
- accurate determination of the mean ocean surface.
CLS activities include a large range of know-how. These skills have been developed within the Ocean, Altimetry and Climate Pole implemented with the support of the Midi-Pyrenees Region. This Pole gathers different teams located in Toulouse, such as CERFACS (European Centre for Research and Advanced Training in Scientific Computation), CLS, CNES (French Space Agency), LEGOS (Laboratory of Studies on Space Geophysics and Oceanography), METEO-France, and SHOM (Hydrography and Oceanography Department of the French Navy).
Moreover, the CLS Space Oceanography Division has gained a European and international reputation materialised by various agreements with the European Space Agency, the "Research" Directorate of the European Union and several co-operations abroad, especially with NASA (National Aeronautics and Space Administration).
It is now possible to monitor oceans from space, and to continue monitoring them in the long run. Without this monitoring, most information and results presented in this issue of MEDIAS News letter would have remained unknown or misunderstood.
In the near future, ocean description will be more and more integrated and operational. There will be more satellite-based measurements, which will be even more accurate. Ocean prediction models will be more and more reliable. It is now possible to design and implement very ambitious projects such as MERCATOR and GODAE, which are presented in this issue.
Because accuracy and operationality are now available, applications become widespread. The users, and among them the scientists and decision-makers of the MEDIAS network, need more and more to have a quick and easy access
to reliable data of ocean observation. This is precisely the service offered by CLS and its Space Oceanography Division.
