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TOPEX and JASON SPACEBORNE ALTIMETERS Jean PLA CNES, Toulouse, France WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 1 Summary Scope of a spaceborne altimeter Frequency plan for TOPEX and JASON Usage of the data Data Assimilation and forecasting WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 2 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 WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 3 Objectives of a spaceborne altimeter WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 4 TOPEX/POSEIDON JASON 1 JASON 2 WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 5 TOPEX/POSEIDON 2500 kg Jason-1 500 kg performances similar to in-flight T/P ones 7 Dec. 2001 TOPEX/POSEIDON (1992) ; JASON-1 (2001) ; JASON-2 (2007-2008) WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 6 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 WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 7 JASON-1 Altitude = 1344 km, beam footprint = 77 km WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 8 Jason-1 Instrument WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 9 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) WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 10 From GEOS-3 to Jason-1 Centimeters Error budget of altimeter missions 100 90 80 Orbit error Alt. Instr. error Ionosphere Troposphere EM Bias 70 60 50 40 30 Ocean signal 20 10 0 GEOS 3 SEASAT GEOSAT ERSI T/P (before launch) T/P (after launch) Jason-1 (before launch) WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 11 TOPEX/POSEIDON RESULTS WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 12 TOPEX/POSEIDON - JASON Achievements WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 13 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. WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 14 El Niño/La Niña as seen by TOPEX/Poséidon (NASA/CNES) WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 15 WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 16 WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 17 MERCATOR : Towards an integrated, multi-parameter approach of ocean modelling and operational forecasting WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 18 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 . WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 19 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 » WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 20 Mercator, towards operational oceanography 2002 1/3° 1/15° 2003 1/15° 2° 1/4° 2004 WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 21 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 threedimensional 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. WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 22 MERCATOR system TOPEX, JASON, ... CORIOLIS WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 23 Altimetry & Oceanography - Operational Organization Research Altimetry missions : Jason, ENVISAT, DORIS/SPOT Other space data (temperature, salinity, colour) Value-added Products Assimilation, forecast : MERCATOR Users In situ Data: ARGO, CORIOLIS WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 24 WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 25 OCEANOGRAPHY APPLICATIONS Navy "See without being seen" Routing "Find the most economical route" Fishing "Find fish" Research "Interesting structures to study" WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 26 Fisheries Altimeter product from T/P and ERS-2 for fisheries in the Indian ocean WMO Workshop, Geneva - March 20-21, 2006 • 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 J. PLA - CNES 27 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. WMO Workshop, Geneva - March 20-21, 2006 J. PLA - CNES 28