1. 1 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES TOPEX and JASON SPACEBORNE ALTIMETERS Jean PLA CNES, Toulouse, France

2. 2 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES Scope of a spaceborne altimeter Frequency plan for TOPEX and JASON Usage of the data Data Assimilation and forecasting Summary

3. 3 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES Topex-Jason Mission Objectives: Scope of a spaceborne altimeter Ocean general circulation Intra-seasonal to interannual sea level variations Long term mean sea level changes Tide observation Wind speed mapping and significant wave height at the ocean surface

4. 4 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES Objectives of a spaceborne altimeter

5. 5 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES TOPEX/POSEIDON JASON 1 JASON 2

6. 6 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES Jason-1 500 kg performances similar to in-flight T/P ones TOPEX/POSEIDON 2500 kg 7 Dec. 2001 TOPEX/POSEIDON (1992) ; JASON-1 (2001) ; JASON-2 (2007-2008)

7. 7 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES Frequency plan of TOPEX/ JASON altimeters C BAND : 5140 to 5460 MHz, 320 MHz bandwidth, linear frequency modulation Fc = 5.3 GHz, antenna gain = 32.2 dBi (3.4° at -3dB), peak power = 17 W, mean power = 0.54 W, PRF = 300 Hz, pulse duration = 105.6 μs 5140 MHz to 5250 MHz, under 4.4: no allocation to EESS (active), no recorded cases of interference Services: Aeronautical Radionavigation Fixed Satellite (Earth to Space): feeder links of non- GSO satellites in the mobile satellite service Mobile WRC(2003): extension from 5460 MHz to 5570 MHz Ku BAND : 13415 MHz to 13735 MHz: 320 MHz bandwidth, linear frequency modulation Fc = 13,575 GHz, antenna gain = 41.5 dBi (1.23° at -3 dB), peak power = 8 W, mean power = 1.52 W, PRF = 1800 Hz, pulse duration = 105.6 μs 13250 MHz to 13750 MHz: allocation to EESS (active): Other services: Aeronautical Radionavigation Space Research For C and Ku BANDS : use of large bandwidths (320 MHz) to estimate ionospheric delay and to get unprecendented accuracy: around 1 cm

8. 8 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES JASON-1 Altitude = 1344 km, beam footprint = 77 km

9. 9 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES Jason-1 Instrument

10. 10 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES Radiometer (JMR) This instrument collects the natural emission by the ground surface and in the atmosphere at three different (18, 21 and 37 GHz) frequency bands. The goal is to determine the water vapour content and in liquid water in the atmosphere, when combining the whole set of measurements within those bands. Therefore, it is possible to know the correction to be applied to the altimetric measurement. ( NASA)

11. 11 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES From GEOS-3 to Jason-1 Error budget of altimeter missions Ocean signal 0 10 20 30 40 50 60 70 80 90 Orbit error Alt. Instr. error Ionosphere Troposphere EM Bias 100 Centimeters GEOS 3SEASATGEOSAT ERSIT/P (before launch) T/P (after launch) Jason-1 (before launch)

12. 12 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES TOPEX/POSEIDON RESULTS

13. 13 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES TOPEX/POSEIDON - JASON Achievements

14. 14 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES MAIN RESULTS Rise of the mean sea level of about 3 cm within 10 years according to TOPEX-POSEIDON Complex interaction between the oceans and the atmosphere. An example is El Niño event: warm waters are pushed to the West coast of South America, disrupting normal winter conditions throughout the Pacific ocean. Reliable predictions of El Niño occurrence will lead to better preparation for its widespread impact.

15. 15 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES El Niño/La Niña as seen by TOPEX/Poséidon (NASA/CNES)

16. 16 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES

17. 17 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES

18. 18 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES MERCATOR : Towards an integrated, multi-parameter approach of ocean modelling and operational forecasting

19. 19 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES OCEAN MODELLING & FORECASTING OCEAN : turbulent & chaotic medium Integrated approach necessary with : –Space based observations –in situ measurements –numerical models –multi-data analysis & assimilation French initiative : MERCATOR Process similar to weather forecast.

20. 20 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES The MERCATOR mission was defined in 1996 by six partner organizations. The project is pursuing three goals: Develop an operational oceanography system Develop downstream oceanography applications Mercator Users : « Sea people » « Science people » « Climate people » « Coastal people »

21. 21 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES Mercator, towards operational oceanography 2002 2003 2004 1/3° 1/15° 2° 1/4° 1/15° Modelisation & Assimilation Observation : Satellite & In situ

22. 22 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES MERCATOR OBJECTIVES For its scientific users, MERCATOR is an operational ocean observatory: by systematically combining, over several years, all the information yielded from observations (measurements reflecting reality) with that provided by the model (a three- dimensional view and a memory of past states), it can produce a view of the ocean that is continuous in both space and time. This integrated view is extremely valuable, as it exists nowhere else. It provides a reference state which can be examined or enhanced … as well as the raw materials to do it. For the ocean, MERCATOR provides information of salinity, state of surface down to 1000 m of depth thanks to the satellite and to the in situ data. The forecast are valid for 2 weeks.

23. 23 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES MERCATOR system CORIOLIS TOPEX, JASON,...

24. 24 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES Altimetry & Oceanography - Operational Organization Altimetry missions : Jason, ENVISAT, DORIS/SPOT Other space data (temperature, salinity, colour) In situ Data: ARGO, CORIOLIS Assimilation, forecast : MERCATOR Value-added Products Users Research

25. 25 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES

26. 26 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES OCEANOGRAPHY APPLICATIONS Research "Interesting structures to study" Fishing "Find fish" Routing "Find the most economical route" Navy "See without being seen"

27. 27 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES Fisheries need to understand, model and predict the effects of ocean conditions on fish populations can help locate areas with a higher probability of finding fish and reduce search time and operation costs description of the upper ocean at high space and time resolution needed start to use external information (e.g. SST, ocean colour, altimetry). a global and integrated approach should allow the development of improved products for fisheries and a better management of stocks Altimeter product from T/P and ERS-2 for fisheries in the Indian ocean

28. 28 WMO Workshop, Geneva - March 20-21, 2006J. PLA - CNES MERCATOR : future activities The MERCATOR mission seeks to develop and deploy a truly operational oceanography system over the next five years capable of analyzing and predicting ocean conditions around the globe : the Centre for Operational Oceanography (C2O) This system will describe and predict ocean conditions over the whole ocean column continuously and in real time, at scales ranging from global phenomena to regional areas.