Jason and our Ocean Planet

Mission Kit

National Aeronautics and Space Administration Jet Propulsion Laboratory Pages 4 and 5 Content Moving towards operational oceanography

Pages 6 and 7 In the footsteps of TOPEX/POSEIDON

Pages 8 to 11 The and its payload

Pages 12 and 13 Launch and first operations

Pages 14 to 16 Ground segment and data processing

Pages 16 and 17 The millimeter per year challenge

Pages 18 to 20 Jason and climate forecasting

Pages 21 to 23 Jason serving seafarers…

Pages 24 and 25 Backed by the world’s scientific community

Pages 26 and 27 French players among the Argonauts

Pages 28 and 29 French - US space cooperation with unparalleled accuracy, surface Moving towards operational , water colors, wind speed and direction, and sea surface oceanography topography.

The Franco-American satellite The oceans are a fundamental element in our planet’s climatic system. TOPEX/POSEIDON was launched We should be able to monitor their conditions at all times, in the farthest in 1992, as a follow-up to reaches of our blue planet. We should be able to describe them, explain SEASAT (1978), GEOSAT (1985). them and forecast their changes. Together with ERS-1/2 (1991, 1995), it showed the wide range of oceanographic applications that can One may wonder if our planet was “predictability” of oceanic changes, be obtained from space. Using very Ocean dynamic topography as seen by the TOPEX/POSEIDON altimeter. The American satellite Seasat, launched incorrectly named—we call it Earth, because it is now accepted that the powerful radar altimetry technology, in 1978, marked the beginning of a new era for oceanography. but water covers 71% of its surface ocean has a fundamental disruptive the sharp eye of this satellite can Progressing from research to of sophistication, the global in-situ and seems to be absent from the and regulating role in the Earth’s detect the slightest variations in practical applications is always observation network will also be other planets in our solar system. climate. sea level with an accuracy of about delicate, and this change is currently enhanced and maintained. This is Water covers 360 million sq. km., 1 centimeter. Satellite altimetry has under way. Regional operational the goal of the ARGO program, more than forty times the size of the Our limited view of the ocean has revolution-ized physical oceanography services have already which will put more than United States, and oceans contain become much sharper over the last oceanography, giving access for been set up; examples are the 3,000 profiling floats across the thirty years. Just a few decades ago, 97% of the liquid water on Earth. the first time to quick, synoptic, SOPRANE system developed by world’s oceans by the year 2005. the thought that we could have a global and regular measurements of SHOM in the north Atlantic and The Jason name continuous, real-time global view of This water, which is in a constant ocean surface topography. The half- the European MFSPP project The success of these initiatives state of flux, plays a key role in million measurements gathered by (Mediterranean Forecasting System has shown that a large number Jason is a figure in Greek mythology. climatic and environmental changes the satellite over all the Earth’s Pilot Project). The next step is of scientific, technical and opera- Leading the famous Argonauts expedition, he went on a search for the on Earth. This is because its inertia oceans every 10 days have allowed to go global, with, in particular, tional skills can be successfully is much greater than that of the Golden Fleece, which was guarded by a scientists to regularly draw up the international program GODAE mobilized to implement opera- dragon in the Black Sea. —its mass is 500 times charts of sea currents, follow their (Global Ocean Data Assimilation tional oceanography, which is now as great. seasonal and annual variations and Experiment), which will be both necessary and feasible. His ship, Argo, provided real-time observe the oceanic signatures of operational in 2003. The information about sea conditions and The Earth’s climate follows the major climatic anomalies, such MERCATOR center, the French Providing weather forecasts for communicated with its crew. After several years of searching, and crossing rhythm of its seasons and its as the 1997-99 El Niño/La Niña part of the GODAE project, will shipping and commercial fishing that heats it unequally. The oceans, the Mediterranean from end to end, phenomenon. This has helped provide high-resolution 3D oceanic fleets, forecasting major abnormal Jason finally reached his goal. atmosphere, landmasses and ice scientists better understand and description and forecasts on a climatic events, and better distribute this heat through the describe the complex mechanisms planetary scale. Since January 2001, managing coastal areas… Every civilization needs myths and natural circulation of winds and sea and interactions among the oceans’ a preliminary operational version of Satellite altimetry data provided by successful quests, and the Argonauts' expedition included both of these. currents. Many oceanic parameters are currently different variability modes. MERCATOR is providing forecasts Jason-1, and a permanent in situ measured from space: , This will also be the case for Jason, water color, wind, waves and dynamic for the northern and tropical areas and satellite observation network, which will showcase the two driving The series of catastrophes we topography. With the TOPEX/POSEIDON of the Atlantic Ocean. While satellite will help us better understand our components of space activity: have experienced in recent years— mission living up to expectations, systems and oceanic models are “ocean planet” and better forecast a quest (research) and a conquest (the the ocean seemed unrealistic; at that flooding, powerful storms, climatic satellite altimetry has become an being developed to increasing levels its changing moods. implementation of applications). time, only partial and intermittent changes related to “El Niño” and indispensable discipline in the “La Niña”—gave us a sudden wake- in situ data was available. This is no longer the case, thanks to the development of a new challenge, up call and made us notice just how that of operational oceanography. deep an effect climatic changes can many that monitor the Earth and its oceans, flying over This challenge has been spurred have on our daily life. Scientists on by the success and interest have also needed to examine the the entire surface of the planet in just a few days, and measuring, generated by recent oceanic space causes, the consequences and the missions and their related research. The ocean is constantly changing: on the surface, these changes can take from a few hours This is the case, for example, to a few years; but in its deepest areas, these changes can occur over several centuries. with several pioneer programs such as WOCE (World Ocean Sea-to-air Circulation Experiment), heat transfer TOGA-COARE (observing climatic anomalies in the tropical Pacific region), and more recently the By the year 2005, more than 3,000 profiling floats, spread out across the Warm shallow CLIVAR (Climate Variability and current world’s oceans, will provide real-time information on the surface and Jason on his ship, the Argo, searching for Predictability) research program. deep layers of the ocean, complementing space measurements. the Golden Fleece.

Cold and salty 5 4 deep current Eddy kinetic energy In the footsteps of T/P - ERS TOPEX/POSEIDON

March 3, 1997 March 23, 1998 The main research objectives for the new Jason-1 altimetry mission were June 9, 1997 defined after examining feedback from the TOPEX/POSEIDON mission. April 10, 1997 May 10, 1997 Sea level anomaly May 10, 1998 The first discipline to benefit from these remarkably accurate tools is physical oceanography. But other disciplines in Earth sciences, also benefited greatly. The El Niño phenomenon was observed in its entirety, and continually, for the first time in 1997-98 thanks to TOPEX/POSEIDON.

Launched into a 66° orbit, at an Multi-season to complex, and are subject to many even using a system as efficient Other applications in altitude of 1336 km, Jason-1 will multi-year variability POP model different types of influence: an and accurate as TOPEX/POSEIDON. geodesics, , follow the same ground tracks as accumulation of organic matter Confirming these observations its predecessor TOPEX/POSEIDON. and fresh water carried by rivers requires the accumulation of several glaciology and hydrology This oceanic variability, which Covering these tracks every 10 days, and streams; glacial action in years of this type of measurement. especially affects major oceanic it will detect the slightest variations high latitudes; coastal swamps; Altimetric sea level measurements in sea level and will provide high- currents, has a significant effect This is why it is necessary to add and interactions between coastal first represent the signal from the quality data to different research on climatic changes. The seasonal Jason-1 measurements to those currents and deep-sea currents. marine geoid, the result of the programs. cycle, for example, leads to an made by TOPEX/POSEIDON. Jason-1, together with the European Earth’s gravity on the ocean, whose increase or decrease in sea level Space Agency’s ENVISAT satellite, amplitude is 10 to 100 times higher in each hemisphere, exceeding will be excellent tools for observing than that of the oceans’ dynamic 15 cm in some areas; there can be and resolving this type of topography. Geophysicists also have significant variations from one year variability. TOPEX/POSEIDON data has helped access to a great deal of data to study to the next. The recent occurrences develop several models that can bathymetry and plate tectonics with of the “El Niño” phenomenon, forecast the main diurnal and semi- levels of precision and resolution especially the pronounced case in Altimetry, used to better describe and Changes in the mean diurnal components of ocean tides that had never been reached before. 1997-98 in the tropical Pacific, are quantify the energy transported by sea level with an exceptional precision of Many other investigations in the extreme examples of these multiyear ocean currents (here, the Gulf Stream), approximately 2 cm. Internal waves, field of earth sciences, such as anomalies. The wave frames that is an indispensable tool for adjusting and validating computerized models of The mean sea level is a significant generated by the tides, have even research on ice, enclosed seas, cross the ocean basins over several oceanic circulation. indicator of global warming. TOPEX/ great lakes, and desert regions, will month-long periods also carry high been identified using estimates of POSEIDON measurements were also greatly profit from Jason-1’s levels of energy that they exchange tidal energy dissipation inferred The TOPEX/POSEIDON mission, dedicated play an essential role in moving used to confirm this trend, already from altimetry. Jason-1 will help altimetric measurements. to the observation of oceanic circulation, with the atmo-sphere. The TOPEX/ observed with -gauges, which revolutionized physical oceanography. POSEIDON mission represented a heat from low to high latitudes. refine these studies. In coastal It was launched on August 10, 1992 by key step in observing this type of Coastal zones, which represent 8% represents an average increase in sea regions, the combination of data an Ariane 4 rocket from Kourou, and is of the oceans’ surface, also undergo level of 2 mm per year. Nevertheless, still functioning after 9 years of faithful variability through the increased from Jason-1 and ENVISAT will service. accuracy of its measurements and a great deal of turbulence. These this extremely small variation is at be particularly beneficial to help the considerable reduction in error areas are especially fragile and the limit of what can be observed, understand the long periods and tide Mean ocean circulation sources. The systematic integration signals with weak spatial scales. of Jason-1 altimetry data in oceanic Describing average currents using models will also play a key role in Sea-state conditions altimetric measurements is essential the description and forecasting of to better understand their influence these phenomena. on the transient move-ments and Altimetry will also provide estimates the physical charac-teristics of of wave height and wind speed, Tide forecasting models have benefited these phenomena. two elements which are of great greatly from altimetric measurement Mesoscale and coastal data. Tides can now be forecast with a This makes it possible to model variability scientific and operational value precision of 2 cm in the middle of the them and develop a more precise The Jason-1 satellite, one- for marine . Several ocean. (M2 component here mapped) initial state for the ocean. Jason-1’s fourth the weight of meteorological centers are already Altimetric data is particularly useful TOPEX/POSEIDON, will measurements, combined with the adding altimetric measurements marine geoid extrapolated from to understand mesoscale oceanic follow the same ground variability. This term covers signals track and will provide to their operational models and current (CHAMP) and future the same level of will benefit from Jason-1’s wind- (GRACE and GOCE) gravimetric with weak spatial scales (a few dozen performance as its wave measurements, which will be space missions, will provide kilometers) and time scales of few precursor. significant contributions to a better months. One example of this is the available less than 5 hours after understanding of this “mean” very energetic eddies that form near being recorded by the satellite. ocean. major oceanic currents, and that

6 7 The satellite and its payload The measurement JMR GPS TRSR POSEIDON-2 DORIS receiver system radiometer altimeter

Jason-1 is the first of a new mini-satellite family. Five times lighter Jason-1 will be carrying a payload and almost three times cheaper than TOPEX/POSEIDON, it uses the of 5 instruments. A bi-frequency PROTEUS multi-mission platform. altimeter called “POSEIDON- 2” and a DORIS orbitography system are provided by CNES. NASA has provided a three-frequency radiometer, a GPS location system has a mass of 275 kg, and the total The satellite and a laser reflector. All these payload mass is 175 kg (instruments instruments, with the exception of and structures). Jason-1 is the first satellite to use the laser reflector, are redundant. PROTEUS the multi-mission Proteus platform, Once the satellite is placed into Proteus is the name of a Greek god, developed as part of a long-term DORIS, together with the GPS and orbit, it will deploy two sets of solar the son of Poseidon, who could change partnership between CNES and laser reflector, make it possible to his shape at will. panels with a total surface of 9.5 m2 Alcatel Space Industries. pinpoint the satellite’s position, with that will generate 500 W of energy Several other uses of the Proteus respect to an Earth-based reference for the platform and payload. platform are planned or currently This three-axis stabilized satellite system, to within one centimeter. being studied, including the CALIPSO is approximately 3.4 m high and The altimeter is based on a radar Altimeter antenna LRA DORIS antenna satellite (CNES-NASA to study clouds While Jason-1 is designed to last for laser retroreflector and aerosols), Corot (CNES, optical will have a total launch mass of 490 system: waves sent from 3 years, its resistance to radiation telescope designed to study the internal kg (including its launch adapter, Jason-1 are reflected by the water An exploded view of the satellite showing the different on-board instruments. structure of stars and to detect their balance weight and propellant). at its orbiting altitude of 1336 km, surface and returned to the planets), SMOS (ESA proposal for The satellite platform, is sufficient to ensure 5 years of satellite. All the science data is stored on The electrical components were Earth observation), Megha-Tropiques operation. The satellite will carry (CNES/ISRO, study of the water cycle with its two star board the satellite in a solid-state manufactured and tested by Alcatel in the tropical atmosphere), and others. trackers, 28 kg of propellant, which is largely The round-trip signal time will memory. They are transmitted each Space Industries in Toulouse, and sufficient for this length of time. be processed to take into account time that Jason-1 is in the visibility development and testing of the GPS antenna were carried out by Alcatel Satellite delays, as the signals cross through of a ground station. DORIS the and the tropo- Space Industries in Cannes. sphere, and the exact distance POSEIDON-2 Radar impulses from the 1.2 m The success of the Jason-1 mission between the satellite and the sea (just like that of TOPEX/POSEIDON) Orbit Jason-1’s radar device is the antenna placed on the nadir face of will be calculated. The difference the satellite will be sent on two depends essentially on the ability POSEIDON-2 solid-state altimeter. between this measurement and the to pinpoint the satellite’s position This was developed for CNES by satellite’s altitude with respect to in orbit with exceptional accuracy. The radar distance between the the Earth, calculated from its orbit, Alcatel Space Industries. satellite and the ocean surface, This data is mainly provided by the is used to obtain the sea level and corrected for atmospheric DORIS system. disturbances, is subtracted from its variations. This altimeter is based on the the satellite’s altitude, as supplied POSEIDON-1 altimeter used in by the orbit calculation, to deduct the height of the sea level In addition, the analysis of the shape the TOPEX/POSEIDON mission. Its compared to an Earth-based and the amplitude of the radar performance has been improved reference system. Ionosphere returned signal gives wave-height through its dual-frequency design, and wind speed respectively. and it is smaller and lighter. Troposphere

The altimeter’s antenna during ground testing. frequencies (13.6 and 5.3 GHz) in Laser station Range order to measure distance and make corrections for ionospheric path DORIS delay directly from the differential station shift of these two frequencies in the ionosphere.

This radar is capable of measuring the distance between the satellite Dynamic topography The two flight models of the radar and the sea surface with a precision Geoid altimeter on ground test benches. of 2 cm at 1 Hz sampling The performances announced were The DORIS antenna, carried by TOPEX/ Sea surface confirmed, especially the noise level of (1 measurement per second) along POSEIDON and Jason-1, is easy to height less than 2 cm at 1 Hz. the satellite track. recognize because of its unique shape.

Ellipsoid 8 9 Used for the first time, on an precise position of the satellite in Laser retroreflector Industrial Partners experimental basis, on the SPOT-2 real time. This “DIODE” function, satellite in 1990, the DORIS system used successfully during the orbit The Laser Retroreflector Array was developed by CNES and built acquisition of TOPEX/POSEIDON, (LRA) is the target for laser tracking The "Poseidon-2" altimeter was by THALES (formerly Dassault then later for SPOT-3 and SPOT-4, measurements sent from ground developed and manufactured for Electronique). Its flight-proven will be implemented on Jason-1. stations. The satellite’s laser tracking CNES by Alcatel Space Industries performance makes it the best It is hoped that it will provide measurements provide a means of (Toulouse). Its antenna was positioning data within 10 cm, developed and tested by Alcatel orbitographic system currently calibrating altimetric measurements Space Industries (Cannes). available. It has achieved which makes it possible to envisage made by the system. The data is international recognition since efficient use of real-time altimetry also used to complement other data The DORIS receiver was manufactured it has been integrated into the data. from DORIS and GPS to provide by THALES (formerly Dassault International Earth Rotation precise trajectory calculations. Electronique) in St Quentin-en- Service. Radiometer Yvelines, France. C-MAC (Argenteuil, The DORIS terminals and antenna are easy The radiometer, shown here with its The retroreflector, placed on the France) provided its highly stable to transport, which ensures ease-of-use in antenna, is used to make precise oscillator and its antenna was The three-channel Jason Microwave measurements of the water vapor content nadir face of the satellite, is totally A network of fifty beacons spread the field, for temporary campaigns. manufactured by Chelton-Starec out across the Earth constantly Radiometer (JMR) is used to of the troposphere and provide data passive. It consists of nine quartz to correct the radar altimeter (Dourdan, France). DACTEM (Alès, records the satellite’s location. These determine atmospheric water vapor measurements. corner cubes arrayed as a truncated France) provided DORIS test and beacons send a dual-frequency content in the troposphere, and cone, with one cube in the center control benches. and the others arranged around signal as the satellite flies over them. complex orbitographic model which the correction to be applied to This new generation radiometer the cone. The reflector provides a The Jason Microwave Radiometer The satellite’s DORIS receiver picks calculates the satellite’s trajectory altimetric measure-ments for radar uses MMIC (Microwave Monolithic field of view of approximately 100 (JMR) was built by the Jet Propulsion up these signals and measures the and its immediate position with signal path delays in tropospheric Integrated Circuit) miniaturization degrees. Distance measurements Laboratory (JPL), Pasadena, Doppler effect – the shift between respect to the Earth. The precision layers. technologies that ensure a high between the ground laser station . the frequency sent and received. validated for the TOPEX/POSEIDON level of reliability, and lower mass and the satellite are precise to less mission is estimated to be between Each of the three frequencies used and power consumption. The JMR The Turbo Rogue Space Receiver system, especially its central channel than one centimeter. DORIS measurements carried out 2 and 3 cm, and it is hoped that is sensitive to different effects. (TRSR) is the GPS receiver developed and its digital monitoring systems, by Jason-1, together with this precision will be within 1 cm The main 23.8 GHz frequency is by the Jet Propulsion Laboratory (JPL) measurements obtained from for Jason-1. are fully redundant. and manufactured by Spectrum Astro very sensitive to water vapor, while Inc., Gilbert, Arizona. instruments on other satellites the 18.7 GHz channel is used (SPOT 2-4 series and TOPEX/ GPS receiver The DORIS receiver on Jason-1 is a to quantify effects from wind- The Laser Retroreflector Array (LRA) POSEIDON) make it possible to miniaturized version of the receiver driven variations in the sea surface. Jason-1’s GPS receiver was provided was manufactured under contract precisely locate the beacons within on ESA’s ENVISAT satellite. The 34.0 GHz channel provides by the Jet Propulsion Laboratory to the NASA Goddard Space Flight an international terrestrial reference corrections for non-rainbearing (JPL) in order to have a Centre (GSFC) by ITE Inc. Laurel, system. In addition, DORIS’s performance Maryland. clouds. By combining the bright- complementary system used to and improved measurements have determine the satellite’s exact ness temperature measurements of The Proteus platform (jointly Doppler-shift effect measurements now made possible the autono- trajectory. The Turbo Rogue Space are sent to the ground and integrated mous navigation of a satellite. each of these three frequencies, the developed by CNES and Alcatel Receiver (TRSR) can continuously Space Industries) and the Jason-1 by the DORIS Orbitography Service This involves adding a function to precise amount of water vapor can and simultaneously receive dual- be determined. payload module were manufactured at the Toulouse Space Center into a the DORIS receiver to calculate the frequency navigation signals from by Alcatel Space Industries. 12 satellites of the GPS constellation in orbit at 20,200 km. The Data Handling Unit (DHU) was The GPS receiver, which receives up to manufactured by SAAB Ericsson More than 50 DORIS terminals are spread around the globe, making a dense network that can tracks the satellite and help a lot in Using these signals, the instrument 12 GPS satellites simultaneously, works Space (Goteborg, Sweden), the Star calculating its orbit with a precision of just 1-2 centimeters. carries out and acquires phase with the DORIS system to calculate the Tracker by EMS (Canada) and the satellite’s trajectography. measurements with a precision GPS platform by LABEN (Italy). The of approximately 1 mm and a gyrometers were built by SAGEM pseudo-distance with a precision of (Eragny, France) and the reaction approximately 10 cm. wheels by TELDIX (Heidelberg, Germany). The telemetry and The GPS data, combined with telecommand unit (TM/TC) was IGS ground-based measurements, manufactured by Alcatel Espazio is integrated with DORIS data (Spain) and its antennas were built by into high-precision trajectography SAAB Ericsson Space. The satellite’s solar panels were built by Astrium models. It is precisely this dual (Ottobrun, Germany). use of complementary geodesics systems, DORIS and GPS, which should make it possible to have measurements of the satellite’s The Jason satellite’s laser reflector is used altitude precise to less than one by the ground laser stations to make centimeter. additional orbitography measurements.

10 11 Launch and first operations

On August 10, 1992, France used an Ariane 4 rocket to put the TOPEX/ POSEIDON satellite into orbit, as part of a Franco-American satellite altimetry mission. This time, the partners have exchanged roles and NASA will be handling the launch of the Jason-1 satellite.

Lift off of a Boeing Delta II rocket.

The Delta II

Jason-1 will be placed into a Force Base. Launch preparation will After a flight of approximately Manufactured by Boeing, and launched 66-degree inclined orbit around the last 7 weeks and will be carried out one hour, Jason-1 will be placed from either Cape Canaveral in Florida Earth at an altitude of 1,336 km. The first in the facilities of Spaceport into orbit about 10 km below or the Vandenberg Air Force Base in California, the Delta II rocket is a flexible satellite will be launched from the Systems International (SSI), then its definitive orbit. A sequence launch vehicle that can be adapted to Vandenberg Air Force Base (VAB) on the Delta launch pad at the Space of maneuvers will then raise its the needs of different missions. Delta II, in California, and will be placed in Launch Complex-2W, (SLC-2W). altitude so that is ahead of or with two stages, can launch up to 5.8 orbit by an American Delta II rocket behind TOPEX/POSEIDON by 1 to tons into . With three built by Boeing. Liftoff will occur after a countdown 10 minutes. stages, the launch vehicle can put 2 of approximately ten hours. In order tons into geostationary transfer orbit and launch interplanetary probes, such The Delta II launch vehicle for Jason-1 to be placed in the same Each satellite will carry out as those sent to Mars. (7920-10) will be equipped with orbit, slightly offset from TOPEX/ measurements on a specific point a recently developed Dual Payload POSEIDON, the launch window will on the Earth’s surface one to The two-stage version of the launch Attach Fitting system (DPAF) that be approximately 20 minutes with 10 minutes apart. The formation vehicle has a diameter of 2.4 m and is will allow the launcher to carry two two possible launch slots (between flight of the two satellites, which composed of a central core stage with –10’ and -1’, and +1’ and +10’). will last approximately 6 months, a Rocket Dyne RS-27A liquid propellant satellites at the same time. Jason-1 (kerosene and oxygen) engine, and to will be launched with TIMED, a NASA- which up to 9 solid fuel GEM boosters Applied Physics Laboratory satellite, can be added. The upper stage uses which will study the an Aerojet AJ10-118K engine with the and lower , little- same propellant. The eventual third- known regions of the atmosphere stage is powered by a Thiokol Star-48A engine. at an altitude of 60-180 km. will be used to cross-calibrate the two altimetric systems, to calibrate Separation and The Delta II rocket used for the Jason-1 Jason-1, physically attached to the the radiometer and to validate the orbit acquisition mission is the 7920-10 two-stage version, top of the support structure, will be measurements made by Jason-1. with nine boosters. With its 10-foot the first payload separated from the payload enclosure, it will stand 40 rocket. Once Jason-1 is deployed, After this calibration and verification meters tall, and its mass at launch will be 230 tons. the Delta rocket will maneuver to period has been completed, following change orbit, and, after the DPAF the recommen-dations of the Jason-1 The Delta launch vehicle is derived from support structure has separated, scientific group, TOPEX/POSEIDON the Thor Intermediate-Range Ballistic TIMED will be placed in its own should be moved to an orbit Missiles (IRBM) from the 1960s. More orbit. whose ground track will be slightly than thirty different versions preceded different from that of Jason-1 the present-day Delta II, whose first until the end of its life span. It launch took place in 1990. Altogether, Before the launch, Jason-1, its through its different versions, more ground support equipment and will supplement Jason-1’s spatio- than 280 Deltas have been launched. control consoles will be sent by temporal sampling to help in All of its missions since 1997 have been plane from Alcatel Space Industries the observation of small-scale successful. in Cannes to the Vandenberg Air The Vandenberg launch site. phenomena.

12 13 has implemented a new generation that can be utilized in conjunction combines these data to create Ground segment and data of ground control. SSALTO with in-situ data or digital models. geophysical products from the (Segment Sol multi-missions mission. processing d’ALTimetrie, Orbitographie et Once it is received on the ground, localisation precise; Multi-mission raw data from Jason-1—and data A version of CMA developed by Altimetry Orbitography and Precise received from TOPEX/POSEIDON— CNES will operate at NASA-JPL to Each satellite has its own ground control system, the infrastructure on Positioning Ground Control), must be pre-processed before being handle data processing from the Earth in charge of controlling its orbit, collecting and processing data from distributed. After the altimetry Jason-1 mission and to provide located at the Toulouse Space data to the American Physical its instruments, and distributing these data to users. Center, will function as ground radar echoes are analyzed, three main geophysical parameters are Oceanography Distributed Active control for the DORIS system and Archive Center (PODAAC). the Poseidon altimeters. produced: A sea level anomaly map produced as - the distance between the satellite part of the DUACS (CNES/CLS) project – one of the many altimetric products now The CMA center in Toulouse also Before SSALTO was deployed in and the surface of the sea, available in near-real time for scientific validates data, based on its large November 2000, a dedicated CNES - the average wave height, and operational applications. experience developed during the Satellite command and - an Earth Terminal Network - the wind speed. center controlled the DORIS TOPEX/POSEIDON mission. It control instruments on the SPOT and handles the simultaneous The control center and the operation These parameters are then corrected different measurements available processing of data from Jason-1 and TOPEX/Poseidon satellites, and the center rely (for command to take into account instrumental (DORIS, GPS and Laser) and a ENVISAT. The Jason-1 Control Ground System POSEIDON-1 radar on TOPEX/ transmission and data acquisition) biases. complex model of the satellite’s includes: upon a ground terminal network of POSEIDON. It also handled data Environmental and geophysical trajectory. SSALTO will continue enhancing two or three earth terminals suitably processing for these instruments. corrections are also provided so oceanographic data received from - a Jason Command Control Center located to allow the required orbit that the users have all in hand For CNES, Jason-1 science data the CMA. Its role is to validate the (JCCC) located in Toulouse. coverage compliant with the data physical content of the data from SSALTO provides a common ground to process and correct the data. processing is handled by the Centre latency requirement. The planned control for altimetry and precise Multimission Altimétrique (CMA, each mission in greater detail, and This center monitors the satellite configu-ration is to have one earth Météo-France participates in this positioning missions (DORIS-SPOT, Altimetric Multimission Center, part to create coherent multi-satellite during the whole mission lifetime. terminal located in Poker Flat, process by providing meteorological products from it. The final goal TOPEX/POSEIDON, Jason-1, of SSALTO) for altimetric data and Satellite control and operations are Alaska and the second one in and atmospheric data which is is to obtain long time series of ENVISAT). SSALTO also provides the Service d’Orbitographie Mission executed from this center until the Aussaguel (France). A third earth essential for these corrections. measurements that can be used altimetry expertise for third-party (Mission Orbitography Service, end of the Jason assessment phase. terminal is available at Wallops While these radar altimetry data to detect multi-year signals and missions (such as ERS-2). also part of SSALTO) for precise After completion of this phase, (USA) for backup. are being processed, the satellite’s to monitor the Ocean over a long preparation of the operation plan, precise orbit is calculated from the orbitography data. CMA then period. navigation functions, platform This new ground control system configuration changes as well as can simultaneously monitor and performance and trend analysis control different instruments of the Three Earth stations and the CNES and are still this center’s responsibility DORIS and Poseidon families, as JPL operations centers control the satellite, collect data and distribute it to users. while routine operations including well as the DORIS ground beacon satellite activities scheduling, network, and data processing for the command plan preparation, DORIS altimetry and orbitography command transmission and payloads on all the satellites. It also telemetry acquisition and routing provides user support for all the are transferred to the NASA POCC. products of these missions. CNES and JPL controllers keep a close - a Project Operation Control Center watch on the satellite at all times. The CNES has support from its located in Pasadena (POCC). subsidiary CLS for SSALTO ground control operations. Symmetrically, During the assessment phase, the The Earth Terminal Network the JMR and TRSR instruments performs satellite telemetry capture, POCC has the role of routing under NASA responsability are its recording and distribution to telemetry from the US Earth monitored and controlled by the the control centers and to the terminals towards JCCC. It also mission centers. Jason Science Data System (JSDS). ensures the monitoring and control The earth terminals also perform of the satellite in parallel with JCCC, the uplink commanding to the JPL Mission and CNES Control and monitors the instruments under The science data Control Centers Orbitography and Mission satellite. (Pasadena - Californie) Centers (Toulouse) US responsability. processing center

This center takes over from JCCC Mission control Users of space oceanography at the end of the assessment phase measurement data expect the data and controls the satellite and the With the prospect of two major processing and production center to associated instruments for the altimetry missions, Jason-1 (CNES/ provide them with geophysical data remainder of the mission. NASA) and ENVISAT (ESA), CNES that can be immediately used, or

Users 14 15 AVISO/PODAAC user services The millimeter Since the TOPEX/POSEIDON satellite was launched, user support for this project has To verify this performance while altimeter, the JMR radiometer and Additional sites are planned in been handled, on the French side, by AVISO per year the satellite is in orbit, the CALVAL the Doris and GPS positioning the Gulf of Mexico and the (Archivage, Validation et Interprétation des (Calibration/Validation) program systems. Mediterranean (Ibiza, Crete). They données des Satellites Oceanographiques; was developed, using the expertise will also be used by other altimeter Archiving, Validating and Interpreting Challenge Oceanographic Satellite data), and by of project teams, processing centers Validation of the Jason-1 system will missions, such as ENVISAT. PODAAC on the US side. More than 500 and partner scientific teams. be assisted by a worldwide network users receive monthly CD-Roms containing Performance goals for Jason-1 of some thirty tide-gauges collocated In addition to on-site calibration satellite data. are very demanding. They can only CALVAL’s activity will begin by Doris and GPS measurements, experiments, CNES and NASA data AVISO distributes Jason-1 be met if instruments are precisely following flight acceptance, when along with several sites located processing centers will carry out mission data and calibrated and monitored constantly the satellite has reached its along the satellite’s ground track. global evaluations of Jason-1 data. products operationally, to ensure that the system operates They will verify the consistency of either through correctly. This is the objective of Earth-based networks, geophysical products using highly satellite uplinks, or, the Jason-1 CALVAL (Calibration- efficient statistical analyses. more classically, on Validation) program. physical media. Sea surface temperature Mean level Significant efforts, involving the AVISO is also CNES Mission Orbitography Service, involved in the as well as other orbitography experts distribution of Performance standards for Jason-1 from the Jason science team, will multi-satellite were specified at an early stage, work on precise orbit validation, products produced after data are following error assessment of the one of the key elements of the processed by the TOPEX/POSEIDON data. The goal Jason-1 mission. CMA (Altimetric was to ensure that the Jason-1 Multimission Center, part of measurement system was at least Many validation experiments will the SSALTO). In a more general manner, its role is to promote oceanic altimetry as precise as its predecessor. be carried out by the Jason-1 activities to the scientific community, The observation of low amplitude oceanic phenomena, such as changes in the mean science team as part of the CALVAL operational services, decision-makers and In order to detect sea level variations sea level of about 2 mm per year, requires precise control of the stability of altimetric program. More than thirty scientific the general public. in the range of one centimeter, systems. teams have offered to participate Just as the CMA has an American errors in the measurement of in the validation activities. Météo- counterpart at NASA-JPL, which is directly distance (provided by radar) and operational orbit, approximately These dedicated sites are not only France will also participate in this derived from the center developed by the satellite altitude (provided by one month after launch. For equiped with tide-gauges to measure Jason 'wind-wave' data validation CNES, AVISO has an American counterpart trajectory calculations) must be approximately six months, Jason-1 local sea level, but also have as well: PODAAC (Physical Oceanography program by comparing estimates Distributed Active Archive Center). This of comparable orders. Another and TOPEX/POSEIDON will fly complementary instruments (GPS, provided by meteorological models. center handles the same distribution objective, important for long-term “in formation” on the same orbit, laser, radiometers, etc.) to validate functions for Jason-1 from JPL in California. monitoring of mean sea level, is separated by just a few minutes. the other geophysical parameters The CALVAL program will ensure The PODAAC center also distributes data from other space oceanography that after calibration the drift of the This will allow ultra-precise cross- used together with altimetric that Jason-1 measurements are measurements, such as wind vector and sea altimetric system should be known calibration of measurements to be measurements. scientifically and technologically surface temperature. to within a range of 1 mm per year. made from the two systems. reliable, not only during the intense The main CNES calibration site, verification period during the first Since early 1999, AVISO and PODAAC have offered a catalogue of products over the The evaluation of the performance used since 1996 for the TOPEX/ 6 to 8 months, but throughout all Internet that allow any user to access basic of an altimetry system depends on POSEIDON mission, is located in the mission. and more detailed altimetric products, or an estimation of errors that may Corsica, on Cape Senetosa, near to formulate specific requests through a occur; some of these come from the Ajaccio. A second site, on the same simple ordering service. instruments themselves, and others satellite’s ground track, will also be Providing very close support and follow-up from environmental conditions used. This is on the Italian island for its users, AVISO and PODAAC’s goal affecting the measurement. of Capraia, located between Corsica is to offer even more efficient service for and the Italian peninsula. the Jason-1 mission and its operational products. The instruments’ operation will be monitored by internal calibration The main NASA calibration site uses data. In addition, ground verification an offshore oil platform, Harvest, sites will be used to obtain in-situ located off the California coast. measurements that can be directly This experiment, begun in 1992 CNES, together with CERGA and IGN, have The Harvest oil rig, off the California compared to data obtained by the just before the launch of TOPEX/ coast, has been used by NASA since 1992 set up sea level and geodetic stations at Senetosa in Corsica to verify and calibrate to verify and calibrate TOPEX/POSEIDON satellite. Operations will concern all POSEIDON, has since been components of the altimetry system providing essential measurements Jason-1 altimetric measurements. altimetric measurements as compared to The ultramobile laser station developped in situ sea level measurements. This system and will be used to evaluate the to monitor and record the system’s by OCA, CNES, IGN and INSU will support will also be used for Jason-1. quality of measurements from the bias and drift. this campaign.

16 17 Jason and climate forecasting

Eusuring the continuity of high precision altimetry missions, like Jason-1, is essential to monitor the ocean changes and understand better their impact on the climate.

In meteorology centres around Within the Centre National de This assimilation will lead to a the world, such as Météo-France’s Recherches Météorologiques à description of oceanic currents, facilities in Toulouse, super- Météo-France, is the Groupe de temperatures and salinity for all the computers crunch numbers Météorologie à Grande Echelle et oceans of the world, and this will 24 hours a day. Most of the time, du Climat (Group for Large Scale be done with a level of precision short-range weather forecasting is Meteorology and Climate). Its goal is that has never before been obtained. January 1997 the highest priority. But, in off-peak to come to a global under-standing Naturally, refining this system will periods, these computers calculate of climatic variations on our planet. require a great deal of effort, which The combination of satellite models developed by scientists CERFACS1 and IPSL2 participate is being shared by the many measurements, in-situ working on longer-term forecasts, in this joint project to model the different national organizations measurements and models show who are trying to better understand the surface and deep transmission atmosphere and the Ocean as a interested in oceanography who the interactions between of warm water which is indicative couple (that is, to understand work together as part of the of the Niño phenomenon over the atmospheric and oceanic Pacific. Scientists can now forecast how these two systems operate project called MERCATOR. The same March 1997 phenomena. better this kind of event. together) in order to provide, effort is made at an international at an experimental level, reliable Weather modeling is a sort of digital level, for instance in the GODAE seasonal forecasts. Other research laboratory where scientists juggle programme. groups around the world (ECMWF, with millions of numbers and initial physical hypotheses to get FNOC…) pursue the same It is essential that high precision as close as possible to reality. objective. altimetry missions be carried out These numbers represent different to maintain and follow-up long- November 1997 parameters spread out over time (air Altimetry data will be essential in term oceanic projects. Among the pressure, temperatures, wind speed helping establish the initial state reasons for this are the following: and direction, sea currents, etc.). of the ocean and its evolution as Calculations are complex, but when precisely as possible. Topographic - Global warming, observed since the computers hand down their ocean data will be incorporated with the beginning of the XXe century verdict, the results can lead to many all the other available data (from through temperature measurements new investigations and a great deal buoys, boats, etc.) in oceanic models on the surface, has led to an increase of progress. so the data will be “assimilated”. in sea level of approximately ten Index NAO

to twenty centimeters. Altimetric scientists better understand the • measurements can confirm this rate mechanisms behind these kinds of of increase and will be used to phenomena. monitor future changes. Observed ocean temperature anomaly in 1997 during El Niño Even though signs of climatic Principal component TOPEX/POSEIDON - The “El Niño” phenomenon (and variability are weaker in other parts Time (month) The increase in the level of the its “La Niña” counterpart), which of the planet, and more difficult to Tropical Atlantic Ocean, which occured occurs in the Pacific, is a special case. detect, scientists are putting a great between winter 1996 and winter Since the beginning of the 1980s, deal of hope in the assimilation of 1997, as observed by TOPEX/POSEIDON new observations and developments altimetric data in oceanic models to (red curve), corresponds to the increase in the North Atlantic in weather modeling have helped further increase our understanding oscillation index (the difference in Observed us better understand this regional of the climate and improve its atmospheric pressure between the Forecast phenomenon that can have global predictability. Azores and Iceland) (dots). Its shows influences. Scientists now that there is a dynamic coupling Comparison between observed and forecasted between the ocean and the temperatures. 1 understand the importance of the Centre Europeen de Recherche et atmosphere. The NAO signal, and Pacific basin and the tropical de Formation Avancee en Calcul other multi-year oscillations in the oceans and how they affect the Scientifique (European Center for Pacific or Antartic, create strong climate of the entire Earth. More Research and Advanced Training in changes in the climate. Long term altimetric series are very useful to The association of oceanic models and atmospheric models will allow scientists, in the years to come, to make reliable climactic forecasts detailed observation from space, Scientific Calculation). understand the related ocean- on a seasonal basis, as for example forecasting El Niño events. using satellite altimetry, will help 2 Institut Pierre Simon Laplace. atmosphere mechanisms.

18 19 One of the first on-line service: Knowing the currents at a depth MERCATOR Jason serving of several hundred, or even 1000 meters can be very useful for Seeing that operational oceanography has seafarers… this type of operation. Platforms the potential to meet their respective needs, such as those in the Gulf of Mexico have suffered severe damage in the six French organizations set up a common Many marine activities will benefit from the monitoring and forecasting of past from very active whirlpools. program in 1997. The objective of this program, ocean dynamic state as derived from altimetric satellite missions. MERCATOR, a partnership between CNES, Precise surveillance of currents and CNRS, IFREMER, IRD (formerly ORSTOM), sea states, which will be available Météo-France and SHOM, is to operationally Every week, several science and of this data to commercial fishing in products derived from Jason-1 implement global oceanic models, at high processing centers around the only date back to 1998. Schools of and ENVISAT data, is extremely resolutions, for research purposes, and to world, including the oceanographic fish can often be found in areas with valuable to better manage pumping develop a variety of applications for marine department of CLS, a subsidiary an abundance of plankton, and that Temperature environments. of CNES, and the Service Hydro- this plankton is often present graphique et Océanographique de in areas of thermal fronts and la Marine (SHOM; French Navy’s MERCATOR has three main goals: modeling, strong currents. Altimetric charts Salinity Hydrographic and Oceanographic acquisition of spatial and in situ observations, can provide important information Department), produce dynamic regarding links between the marine and assimilation of these data in ocean models. Ocean topography topography charts of the sea, which environment, as seen on the charts, The system depends heavily on the existence are very useful for all those who and the rate of fish reproduction and continued availability of altimetric data, but work at sea. and their life cycle. In addition also on other satellite observation systems and to assisting commercial fishing, in situ networks, leading to close coordination Computers will have processed at these altimetric products can help with the various projects planned. International length the altimetric data (TOPEX/ better manage variations in fishing collaborations have been set up, such as those POSEIDON, then Jason-1, ERS then resources according to fishing The increasing depth of oil drilling requires a better knowledge – and more reliable with researchers from the European Center for The Mercator system, operating since January 17, 2001, produces every week ENVISAT) to extract pertinent data campaigns. Jason-1 also has a 3D analysis and a two-week forecast of the sea state in the form of current, on current positions and intensity, forecasts - of sea currents. Medium Range Weather Forecasting (ECMWF) dynamic topography, salinity and temperature maps. Mercator is the first link applications useful for managing and the UK Met Office. in the international operational oceanographic experiment GODAE planned the presence and scales of eddies fishing quotas and “intelligent for 2003-2005. and thermal fronts. operations and to better design fishing”. platforms. An initial MERCATOR prototype, functioning since January 2001, is creating real-time Fishing The fishing industry is a promising All petroleum prospecting zones in products for the North Atlantic. For a given market for altimetric products. After deep water are concerned, especially date, a diagnosis of the oceanic situation and The fishing industry is one of the an initial demonstration phase, those off the coast of Europe more detailed products will be a forecast over several days will be provided. main users of altimetric products, (Norway, Irish Sea, etc.) but also even though the first applications available including altimetric data Users of these data, such as the French Navy, those in the Gulf of Guinea and off and measurements of sea the coast of Indonesia. will use these products in pilot applications. temperature and color by satellite, These products will eventually play a key role before three-dimensional modeled in seasonal climatic forecasting systems and products are developed. CLS is one Navigation operational systems for coastal oceanography. Satellite of the leading companies in this observations field. The French Navy has been using MERCATOR is the French contribution to altimetric data regularly and GODAE (Global Ocean Data Assimilation operationally since 1998, and the Offshore Petroleum US Navy has developed a similar Experiment). This international experiment, operational system. Each begun in 1997, is designed to demonstrate the Model Forecasts The offshore petroleum industry Wednesday, French navy ships at feasibility of operational oceanography, using is also interested in altimetric sea receive a chart of the northeast systems to assimilate spatial and in situ data in products because petrol companies Atlantic, developed from oceanic oceanic models. MERCATOR and all the other are going further from the coast models that include measurements in situ The correlation between albacore tuna from TOPEX/POSEIDON and ERS. forecasting centers around the world (United observations and into deep water. The technology catches (indicated by colored dots) and This system, “the Systeme States, Japan, Australia, etc.) will share their sea level anomalies deducted from used in these cases is to have Operationnel d’Analyse et de forecasting models and provide their partners altimetric measurements shows that the wellheads installed on the sea Previsions” (SOAP; Operational with their results during the intensive three- catches are made at the edges of warm bottom. Oil is brought to the whirlpools (positive sea level anomalies). Analysis and Forecasting System), year period of GODAE activity, from 2003 This type of study is especially useful surface through flexible umbilicals was developed and implemented by to 2005. Operational oceanography will then to better understand the way different to barges anchored above the site, the Toulouse branch of the Service progressively be accepted at the same level as The Mercator system uses satellite measurements (especially altimetric data), species of fish live and better manage and tankers then remove the oil Hydrographique et Oceanographique in-situ measurements and a high-resolution model (to a few kilometers) to fishing resources according to fishing meteorology is today. describe the physical sea state. efforts. from these barges. de la Marine (SHOM).

20 21 SHOM has a dual mission: to As with TOPEX/ Information is provided to local by diffusiometers, are currently support naval forces, and to provide POSEIDON and ERS, authorities to assist them in decision provided by the ERS-2 satellite. the combination of making. Jason-1 and ENVISAT a public service. The public service ENVISAT and Jason-1 Météo-France uses these data each mission consists in ensuring safe measurements will altimetric data will help verify storm day in VAG, its sea state forecasting navigation, creating sea charts allow scientists to surge forecasts, and, integrated model. The European Center for detect and monitor in real time into meteorological and developing documentation for Medium-Term Weather Forecasting small-scale eddies models, even improve them. (ECMWF) does the same with the navigation, such as tide tables. As phenomena present wave model WAM. part of the Navy’s environmental in the Mediter- Satellites ERS-1/2 tracks support mission, SHOM provides the ranean. It is used Forecasting Drift by the European Satellite TOPEX/POSEIDON tracks WAM and VAG simulates the Navy with more specific forecasting pilot project MFSPP evolution of different wave sets and and analysis data concerning the (Mediterranean Drift results from the combined swells, which are superimposed, and sea environment. Water masses, Forecasting System actions of wind, tide currents and Pilot Project) forecasts the sea state on all parts temperatures, currents, eddies and oceanic circulation, on an object provide analyses of the Earth, with a higher level the position of fronts in the open and forecasts of lost at sea. Drift forecasting requires The ENVISAT satellite will carry a payload of precision for Europe. Météo- sea are essential information to physical and special oceanic models, used in of several instruments including an biogeochemical France provides sailors with regular help both surface and underwater conjunction with tide and wind altimeter that will be used for a mission parameters of the forecasts and special weather complementary to that of Jason-1. navigation. Mediterranean. forecasts, coupled with models updates when weather conditions describing the behavior and changes deteriorate. SOAP’s oceanic forecasts, which of the drifting objects. These ENVISAT, the Fellow Traveler may extend as much as 14 days, Sea level variability complex tools are used operationally (cm). The ERS-2 observation mission The European Space Agency’s ENVISAT are developed from models that by Météo-France, in collaboration (launched in 1995 with a life span mission is ambitious and innovative. integrate satellite altimetry data with Cedre (CEntre de of 3 to 5 years) will be continued This polar platform for observing the Earth (from TOPEX/POSEIDON/Jason, Documentation, de Recherche et by ENVISAT and Jason-1, and these will study the Earth’s surfaces, atmosphere, ERS/Envisat, etc.), water surface oceans, and ice caps for a period of five d’Experimentation sur les pollutions satellites will provide data with a temperature data (from NOAA years. accidentelles des eaux; Center delay of 3 to 5 hours. Thus, Jason-1 satellites), wind force data (from for Documentation, Research and will offer a potential for progress weather satellites), and in situ This very large satellite (more than 10 m Experimentation on Accidental in all areas of marine forecasting: high and with a mass of 8 tons) will carry Water Pollution) for sea pollution, forecasting of sea state, but also no fewer than ten instruments, including together with sea authorities and storm surges and drift. an altimeter (RA-2; Radar Altimeter 2) Coastal Surveillance exists: it is called a negative surge. CROSS (Centres Regionaux and CNES’s DORIS positioning system. When a hurricane or a depression Operationnels de Surveillance et The dual-frequency radar altimeter, approaches a coast, these two de Sauvetage; Regional Operational derived from that used on ERS-2, has been Another field of activity where designed to carry out measurements on all phenomena combine. In some Centers for Surveillance and Rescue) altimetric data is useful is that areas with certain geographic types of surfaces. It will map the oceans, during search and rescue concerning coastal areas where characteristics, such at the heads of sea ice, polar ice caps and most of the there are many problems related bays or gulfs, this accumulation of operations. planet’s landmasses. to risk prevention and coastal water can be amplified. development. The altimetric Since the assimilation of Jason-1 Data acquired by ENVISAT will then be products currently available need data will improve oceanic models, used to support global climatic research. The increase in sea level can It will help better monitor environmental to be merged to observe coastal sometimes reach several meters forecasts for high areas with a better resolution, and to changes and contribute to the development (6 meters when hurricane Hugo sea drift will be of operational and commercial applications. observe small scale and short reached the East coast of the United more efficient. term features present in the regions States in 1989 and 1.5 meters on Forecasting drift While Jason-1’s orbital cycle is 10 days, such as coastal tides and currents. the French Atlantic coast during near the coasts, ENVISAT - like ERS - has a 35-day cycle. In the near future, the rapid progress The dynamic topography data provided the storm of December 27, 1999). which is essential Its altimeter "sweeps" the oceans much by altimetric satellites, used, for expected in terms of high-resolution Storm surge effects can be especially when any pollution more densely. It can detect oceanic example, in the French Navy’s SOAP modeling and the production of destructive on the shoreline where phenomena on a much smaller scale than oceanic forecasting model, is essential occurs in the sea, adequate data sets should make it most populations and activities are Jason-1. This difference makes the two to predict changes in the ocean’s small will also benefit. eddies. possible for a significant level of concentrated. missions highly complementary. support to be provided. measurements. In the near future, Negative storm surges which occur Marine other data sources will be used, and in high pressure situations have fewer safety risks but can Meteorology the scope of this project will be Anticipating Storm Surges nevertheless be a problem for the extended to the north Atlantic and operation of large ports. Satellite altimetry the Mediterranean. Performance provides real-time will also be improved as more A positive storm surge is an Météo-France and other oceanic observa- efficient models are developed as abnormal increase in sea level meteorological offices around the tions of the sea-state (wind, waves…) Wave height and wind speed data, less part of the pluri-organization project caused by low pressure or high world have developed oceanic to meteo-rologists, and these data than 3 hours old, will be provided by MERCATOR, in which SHOM is an winds blowing from the sea toward modeling systems to forecast storm can help them develop forecasts. Jason-1 and used in operational sea state active participant. land. An opposite phenomenon also surges and prevent eventual risks. These data, as well as that produced models to improve forecasts.

22 23 Germany SCHROETER Jens AWI, Bremerhaven Australia BURRAGE, Derek M Australian Institute of Marine Science, Queensland Backed by the world’s scientific The Jason CHURCH, John CSIRO, Hobart, Tasmania Chile community science team ABARCA Rodrigo University of Chile, presently at CS Group, Toulouse Denmark KNUDSEN Per KMS, Kobenhavn During a scientific symposium at Venice, in 1980, results from United States ARNOLD, David V Brigham Young University, Provo, UT the Seasat satellite, the second altimetric satellite launched by the BORN, George H University of Colorado, Boulder, CO Americans, were presented. The participants then had the opportunity to BUSALACCHI, Antonio J University of Maryland, College Park, MD realize the extraordinary potential of altimetry for studying the oceans. CHAO, Benjamin Fong Goddard Space Flight Center, Greenbelt, MD CHELTON, Dudley B Oregon State University, Corvallis, OR So much progress has been made since then! CHENEY, Robert E NOAA Lab for Satellite Altimetry, Silver Spring, MD EANES, Richard J University of Texas Austin, Austin, TX EMERY, William J University of Colorado, Boulder, CO FREW, Nelson M Woods Hole Oceanographic Institution, MA FUKUMORI, Ichiro Jet Propulsion Laboratory, Pasadena, CA GILLE, Sarah Scripps Institution of Oceanography, La Jolla, CA GLAZMAN, Roman E Jet Propulsion Laboratory, Pasadena, CA HAINES, Bruce J Jet Propulsion Laboratory, Pasadena, CA HANCOCK, David W NASA/GSFC, Wallops Island, VA JACOBS, Gregg A NRL, Stennis Space Center, MS In 1987, when CNES and NASA issued The knowledge KOBLINSKY, Chester J Goddard Space Flight Center, Greenbelt, MD MAC MILLAN Daniel NASA/GSFC, NVI, Greenbelt, MD the announcement of opportunity to select acquired by MERRIFIELD, Mark A University of Hawaii, Honolulu, HI researchers who would provide support TOPEX/ MITCHUM, Gary T University of South Florida, St Petersburg, FL for the TOPEX/POSEIDON mission during POSEIDON has NEREM, R Steven University of Colorado, Boulder, CO led to more O'BRIEN, James J Florida State University, Tallahassee, FL its development and operation stages, the PONTE, Rui M AER Inc, Cambridge, MA response was overwhelming. More than 40 de-tailed discus- QIU, Bo University of Hawaii Manoa, Honolulu, HI teams, containing over a hundred scientists sions of the RAY, Richard D Hughes STX Corporation, Greenbelt, MD many scien-tific RIES, John C University of Texas Austin, Austin, TX of all nationalities, were selected on the RODRIGUEZ, Ernesto Jet Propulsion Laboratory, Pasadena, CA, basis of their research proposals. results obtain- ROEMMICH, Dean University of California San Diego, La Jolla, CA ed, during the RUF, Christopher S University of Michigan, Ann Arbor, MI s c i e n t i f i c STAMMER, Detlef Scipps Institution of Oceanography, La Jolla, CA Through exchanges with technical teams, group’s mee- STEWART, Robert H Texas A&M University, College Station, TX these scientists helped develop the STRUB, P Ted Oregon State University, Corvallis, OR tings (appro- specifications for the geophysical and TOKMAKIAN, Robin T Naval Postgraduate School, Monterey, CA ximately one per VANDEMARK, Douglas C GSFC/Wallops Flight Facility, Wallops Island, VA instrumental performance of the system. year), but also WATKINS, Michael M Jet Propulsion Laboratory, Pasadena, CA WHITE, Warren B University of California San Diego, La Jolla Once the satellite was launched, they were on potential involved in quality control of measurements, France improvements to ARNAULT Sabine LODYC, IRD, Paris in upgrading the data-processing algorithms the system. BAHUREL Pierre SHOM/CMO, Toulouse and in the scientific enhancement of data. As The main goal has BOULANGER Jean-Philippe LODYC, CNRS, Paris early as 1993, they recommended that NASA been to continue CAZENAVE Anny LEGOS/GRGS/UMR5566, Toulouse DE MEY Pierre LEGOS/GRGS/UMR5566, Toulouse and CNES begin working on a successor making TOPEX/ EXERTIER Pierre OCA/CERGA, Grasse to TOPEX/POSEIDON to ensure that these POSEIDON class high- EYMARD Laurence CETP/IPSL/CNRS, Vélizy measurements be continually available. precision altimetric mea- KERLEGUER Laurent SHOM/CMO, Toulouse LE PROVOST Christian LEGOS/GRGS/UMR5566, Toulouse surements over the long term LE TRAON Pierre-Yves CLS, Toulouse In addition to this core group of researchers, to better sample and analyze the LEFEVRE Jean-Michel Météo-France, Toulouse hundreds of other researchers use the freely wide range of oceanic variability. But, MORROW Rosemary LEGOS/GRGS/UMR5566, Toulouse the scientific group also recommended PARK Young-Hyang LOP Museum, Paris distributed data of the mission. Currently, PETIT Michel IRD, Montpellier more than 500 international research teams doing everything possible to improve the PICAUT Joel IRD, LEGOS, Toulouse work with TOPEX/POSEIDON data. This system’s performance. This effort was undertaken, PROVOST Christine LODYC, CNRS, Paris especially through the development of even more efficient ROGEL Philippe CERFACS, Toulouse partnership between these scientific and TOURNADRE Jean IFREMER, Brest technical teams was so rewarding for the geophysical models and more adequate means of controlling the VERRON Jacques LEGI, Grenoble TOPEX/POSEIDON mission that CNES and quality of the measurements. WILLIS Pascal IGN, St Mandé NASA decided to maintain it for the Jason-1 Great Britain Once again, the calibration measurements and validation of the new BELL Mik UK Met Office, Berkshire mission and made a new announcement of Jason-1 system will require a great deal of involvement from the CHALLENOR Peter SOC, Southampton opportunity in 1997. COTTON David Satellite Observing Systems, Godalming, Surrey scientists working on this project. During the verification phase, MOORE Philip University of Newcastle, Newcastle teams belonging to the scientific group will be the first to receive WOODWORTH Philip POL, Merseyside This led to the selection, in 1998, of a new Jason-1 measurements to make exhaustive analyses before providing Japan Jason-1 scientific group composed of 68 the data to their colleagues around the world. There is no doubt that IMAWAKI, Shiro Kyushu University, Kasuga, Fukuoka teams from around the world (including the many results obtained from these measurements will help further New Caledonia more than 200 researchers). our knowledge of the ocean even more. CALMANT Stéphane IRD, Nouméa The Netherlands SCHRAMA Ernst DEOS, Delft 24 25 French players among the Argonauts

In recent years, many French laboratories, organizations and companies have become involved in the use and analysis of satellite altimetry data and the definition and development of new altimetric missions.

This sector has led to the creation, in Computation (CERFACS), which de l’Espace exhibition complex has Toulouse, of a Space Oceanography works with Météo-France Research also helped promote space activities Group which organizes local group (CNRM) to create advanced to the general public. resources in this field, from the models that couple oceanic and development of on board atmospheric data to develop seasonal On a national level, Thomson instruments and their software climatic forecasting systems. Detexis, CEPE and Starec were to the scientific analysis of involved in the manufacture of measurements and the distribution the DORIS system, and many of specific products. In addition to researchers from the National CNES, prime contractor in charge Center for Scientific Research, of space projects and systems, the Universities, Observatories, the other partners involved are: Institute of Research for Development, the Museum of - Collecte Localisation Satellites Natural History, IFREMER and (CLS), center for processing and National Geographic Institute (IGN) analysis of spatial oceanographic are involved in the Jason-1 scientific data and the enhancement of group. Some of these are: altimetry applications, - Météo-France, which uses - The Dynamic Oceanography and altimetry for diagnostic studies of Climatology Laboratory (LODYC), Since many years, french and american project teams works hand in hand to make successful TOPEX/POSEIDON sea states and forecasts for marine at Paris VI University, which uses and Jason-1 missions. meteorology and coastal dynamics, altimetric data to study oceanic - The French Navy’s Hydrographic processes and modeling, and Oceanographic Department - The Laboratory for Geophysical (SHOM) which has developed a and Industrial Fluid Flows (LEGI), system dedicated to oceanic analysis in Grenoble, whose scientists work The French scientific community involved and forecasting for the north in space altimetry projects is especially on the assimilation of altimetric data Atlantic, active and includes technicians, engineers into oceanic circulation models, and valorizing satellite data, and - A team from the Center for Geodesy (GRGS) which itself is - The Laboratory for Geophysical and scientists from many disciplines. - The Laboratory for Physical does research using altimetric data Terrestrial and Planetary involved in the development and and Spatial Oceanographic Studies Oceanography, part of the Museum to study sea states and their effect Environmental Studies, in Velizy, is improvement of gravity field measurements for better modeling. (LEGOS), CNRS/CNES/UPS, a In addition to these different of Natural History in Paris, involved on radar signal physics, working on improving knowledge of laboratory doing research in organizations in the Midi Pyrénées in the study of Antarctic circumpolar - The Institute of Research for the highest layers of the atmosphere In addition to these French scientific region of France, other industrial Development (IRD) has several and their effect on the propagation oceanography, geophysics and current dynamics, teams, many scientists from the partners are involved: Alcatel Space teams, based in Nouméa, Toulouse, of radar signals, glaciology, which works in many - The Laboratory for Ocean Physics United Kingdom, Germany, the - A CERGA team from the Côte areas such as oceanic dynamics, Industries, which designed and (LPO), part of the IFREMER center Paris, Montpellier and Brest, who Netherlands, Denmark, Spain and mean sea level, tides, ice, NAO, manufactured the POSEIDON in Brest, which uses both in situ use altimetric data to carry out d’Azur Observatory is involved in Italy provide their expertise to El Niño… The Center for Ocean altimeter and the PROTEUS and altimetric data to study oceanic geophysical and oceanographic verifying and validating altimetric the Jason scientific group, in Topography (CTO) is also part of platform, and the many computer variability, studies in tropical areas, measurements and tracking complement to the many Ame- LEGOS. service suppliers involved in the - The Department of Space - The National Geographic Institute altimetry satellites by laser, as part rican, Australian, Japanese and - The European Center for Research development of ground control and Oceanography, also part of provides expertise in the field of of geodesic activities carried out Chilean scientists contributing to and Advanced Training in Scientific data analysis software. The Cité IFREMER, is involved in processing terrestrial reference systems, by the Research Group in Satellite this project.

26 27 French - US space cooperation

Since its creation in 1962, CNES has maintained an important program of in the exploration of Mars. CNES, FUSE (Far Ultra Violet Spectroscopic (ATV) launched by ARIANE. These Data Collection cooperation with the main American space organizations. together with its American partners, Explorer) satellite, a relay for data ATVs will be used for logistical is examining the possibilities of a collected by the Mars Global Surveyor, flights to the International Space CNES and NOAA (National Oceanic partnership that will lead to the a gravimetric experiment as part Station. and Atmospheric Administration) This cooperation, mainly carried scheduled to be launched in 2004, return of Martian soil samples at the of the NEAR (Near Earth Asteroid have long cooperated, operating out with NASA, covers the following will study clouds and aerosols first possible opportunity. The two Rendezvous) mission, and French and American scientists have the Argos and Cospas-Sarsat areas: observation of the Earth and their impact on the Earth’s jointly developed several projects Agencies are currently negotiating experiments in aerosol collection and operational data collection and its environment (TOPEX/ radiation balance. CNES will provide in areas such as life sciences and a Memorandum of Understanding pyrolysis from Saturn’s moon Titan, systems. POSEIDON, Jason and CALIPSO a PROTEUS platform and infrared physics in microgravity. The Ramses, defining the key aspects of this as part of the Cassini Huyghens missions), space science, exploration imaging instruments. To continue Kinelit, Biorack and Echographe cooperation. An orbiter and mission. Argos is an environmental data of the solar system (especially experiments, developed in France, after Jason-1, in 2005 the Jason-2 netlanders provided by CNES will collection system, which has been Mars), astronomy, astrophysics, were launched on the space shuttle mission, should be realized, for be the centerpiece of the mission operational since 1978; the payloads microgravity science and manned to study plant biology, cardiovascular a launch, within a partner ship planned for 2007, and the two Sciences in developed by CNES were launched space flights, and data collection. between CNES, NASA, EUMETSAT Microgravity and regulation and electrophoresis. organizations are studying the use In April 2000, the “Kinelit and on NOAA’s polar meteorology and NOAA. of an ARIANE 5 rocket to carry Manned Space Flights Development” experiments flew satellites. Observation of the them. CNES and NASA are also onboard the NEUROLAB mission. Earth Space Science considering carrying out a series of In October 1995, ministers of the ESA The STS-93 mission, which involved France and the United States have small missions to Mars together. member countries decided to develop the French astronaut Michel Tognini worked together since 1982 on In addition to the TOPEX/ Franco-American cooperation in a European program to participate in July 1999, also carried the French an alert and rescue program POSEIDON and Jason-1 programs, this area occurs through programs This is the most recent development in the International Space Station. ICMS (Integrated Cardiovascular called Cospas-Sarsat. NOAA has in late 1998 NASA and CNES of the European Space Agency and in a collaboration that has seen France is the second leading Monitoring System) experiment. launched search and rescue decided to continue cooperating in as part of bilateral relations between many French scientific instruments contributor to this program, which As for the French astronaut Philippe payloads, supplied by France, on 4 this area with the Franco-American CNES and NASA. launched on missions carried out essentially involves the supply, by Perrin, he will be making his first satellites. Since the beginning of CALIPSO mission (formerly ESSP3- The major bilateral program for the in conjunction with NASA: a large- Europe, of a European laboratory, spaceflight on the American Shuttle this program, thousands of lives CENA mission). This mission, coming years involves cooperation scale holographic network for the and automated transfer vehicles in March 2002 (STS-111). have been saved.

The Mars Premier sonde CALIPSO satellite

The ATV "en route" for the ISS The cospas-sarsat system

The Mars north pole ice cap The french astronaut Philippe Perrin 28 29 Edition, November 2001 by the CNES Publications Department, Public Relations and Education Office. Editorial Board: Martin Ransom, Yves Ménard, Patrick Vincent, Eliane Moreaux, Nicolas Picot

English translation: Martin Ransom

Contributions from: Equipe CNES projet Jason, Groupe scientifique Jason, CLS/Division Océanographie Spatiale, Météo-France/PréviMar, Météo-France/CNRM, CERFACS, SHOM/CMO, projet Mercator, LEGOS, LODYC, Direction des Programmes CNES

Design: Active Design - Illustrations: David Ducros Printing: Imprimerie du Sud

Source : CNES, NASA, JPL, GSFC, ESA, NOAA, Washington University-SSEC-SeaWIFS project, Boeing, Alcatel Space Industries, IFREMER, Météo-France, LODYC, ArianeEspace, Spectrum Astro Inc., Arguello Inc., Jhon Egan, TOTALFINAELF, LEGOS/GRGS/UMR5566, SHOM/CMO, CLS, CNRS/INSU, IRD, CERFACS, IGN, Mira Productions, Projet Mercator

31 Centre National d’Etudes Spatiales

CNES is France’s national space agency, tasked with developing France’s space activities since 1961. Its mission is to help shape France’s space policy and to implement space programmes, working in partnership with industry, research organizations and the defence establishment.

CNES is involved in a wide range of activities, including Earth Observation, Telecommunications, Sciences of the Universe and Human Spaceflight Missions. Since 1972, it has been delegated as prime contractor of the Ariane space programme by the European Space Agency (ESA).

For further information, visit the CNES website at: http://www.cnes.fr - www.cnes-tv.net or: http://www-aviso.cnes.fr

NASA (National Aeronautics and Space Administration)

Fore more than 40 years NASA has proudly held an unparalleled record of accomplishment in science, aeronautics and space. Since its inception, NASA has been at the forefront of the human quest to expand horizons, both geographic and intellectual.

NASA’s mission is to advance and communicate scientific knowledge and understanding of the Earth, the solar system and the universe ; to advance Human Exploration, use and development of space ; and to research, develop, verify and transfer advanced aeronautics and space technologies. Five strategic enterprises comprise NASA’s primary mission areas: Space Science, Earth Science, Biological and Physical Research, Human exploration and Development of Space, and Aerospace Technology.

NASA Website: http://www.nasa.gov

National Aeronautics and Space Administration Jet Propulsion Laboratory