Satellite Altimetry Status & Products – Part 1 J. Lambin, CNES G. Dibarboure, CLS

2nd GODAE Observing System Evaluation Workshop - June 2009 – J. Lambin 2 Satellite altimetry: users needs as seen by space agencies ■One « high accuracy » reference mission  TOPEX/Poseidon, Jason series (including Jason-3) => to be continued by Jason-CS?  Payload required:  Dual-frequency altimeter,  Microwave radiometer,  Precise orbit determination suite (GPS, DORIS, laser)  Orbit  Minimizing tide aliasing: non-sunsynchronous, mid-inclination  Suitable for POD (high altitude)  Data latency: 3h / 2 days / 2 month ■One at least (ideally 3) other altimetry missions (ERS, GFO, ENVISAT…)  less demanding POD => post-calibrations using reference mission, SSO OK  Mesoscale oriented => better spatial coverage, but longer cycles ■Future generation / alternatives  Swath altimetry: SWOT  Constellations (Iridium-NEXT?)

2nd GODAE Observing System Evaluation Workshop - June 2009 – J. Lambin Jason-1 Fr./USA ENVISAT ESA High accuracy SSH from mid-inclination orbit CRYOSAT-2 ESA Medium accuracy SSH from high-inclination sun-synchronous orbit Jason-2 Europe/USA Jason-3 Europe/USA Jason-CS/Jason-4 Europe/USA Swath altimetry from high-inclination orbit (several orbit options) SWOT/WaTER-HM USA/Europe Saral/AltiKa India/France Jason-CS successor Europe/USA In orbitApprovedPlanned/Pending approval Needed Orbit to be assessed Sentinel-3B, -3C, -3D Sentinel-3A Europe HY-2B, -2C, -2D HY-2A China ERS-2 ESA Ocean Surface Topography Constellation Roadmap GFO NOAA GFO-FO NOAA

2nd GODAE Observing System Evaluation Workshop - June 2009 – J. Lambin 4 Current altimetry missions ■Jason1: in extended mission, fully operational  Moved to interleaved orbit with Jason-2 in Jan/Feb 09, after 6-month « formation flying phase »  Vulnerable to equipments failure risk ■Jason-2: lauched in June 2008,  OGDR distributed operationally since Dec 2008,  IGDR distributed operationally since Jan 2009  GDR will be released after OSTST (July 2009)  DUACS products already available  Very good product quality ■ENVISAT  excellent synergy with Jason1 (T/P and ERS complementarity further improved)  S-band missing: degraded quality by lack of ionospheric delay correction  Will be put on a drifting orbit in 2010 Jason-1 vs Jason-2 SSH differences DUACS map of SLA – J1+J2+EN

2nd GODAE Observing System Evaluation Workshop - June 2009 – J. Lambin 5 SARAL/AltiKa ■Cooperative framework : CNES/ISRO ■Altimetric Gap filler between ENVISAT & SENTINEL3  Research oriented mission :  new, higher frequency, greater performance  potential new applications on ice, land, coastal areas  …but with a consolidated architecture : conventional altimeter ■Tentative launch date : mid- to end-2010 ■Payload:  AltiKa: Ka-band altimeter (higher accuracy, no need for a 2nd frequency) + Dual-frequency radiometer (sharing the same antenna)  POD: DORIS/LASER ■Orbit: same as ENVISAT (sun-synchronous, 35-day cycle) ■Data policy : ~ the same as JASON missions (through CNES/ISRO RAs)  Next India/France scientific workshop on 3-5 december in Ahmedabad  International Research Announcement planned in 2009

2nd GODAE Observing System Evaluation Workshop - June 2009 – J. Lambin 6 Sentinel-3 ■ESA mission, in the frame of GMES program ■Mission Profile:  7-year lifetime (consumables for 12 years)  SSO orbit (10h descending), 27-day repeat cycle, 98.65° ■Satellite Payload:  Ocean and Land Colour Instrument (OLCI)  Sea and Land Surface temperature (SLST)  Sentinel-3 Ku/C Radar Altimeter (SRAL)  Dual Frequency MicroWave Radiometer (MWR):  POD: GPS/DORIS/Laser ■Products: 3h / 1-2 days / final after POD

2nd GODAE Observing System Evaluation Workshop - June 2009 – J. Lambin 7 HY-2A mission description ■Chinese oceanographic mission (+ French participation) ■Launch planned Sept 2010 ■Payload:  Dual-frequency altimeter Ku/C  nadir 3-frequency radiometer  5-frequency scanning radiometer  Wind/wave scanning scatterometer  DORIS/GPS/LRA ■Orbit (sun-synchronous 6-18, 99.35°):  First 2 years with a 14-day cycle  Then one year with geodetic orbit (168-day cycle, 5-day approx. subcycle) ■Products availability?  Through DUACS multi-mission products (not confirmed yet) geodetic orbit after 3 days One day of the 14-day orbit

2nd GODAE Observing System Evaluation Workshop - June 2009 – J. Lambin 8 Cryosat-2 ■ESA mission, to be launched in Nov 2009 ■Objective: to determine fluctuations in the mass of the Earth’s major land and marine ice fields ■Mission description: ■Lifetime 3 years + 6 month comissioning ■Orbit  LEO, non sun-synchronous  Repeat cycle: 369 days (30 d sub-cycle)  Mean altitude: 717 km  Inclination: 92° ■Spacecraft and Payload recurrent from lost CryoSat 1 ■Instruments  SIRAL (SAR/Interferometric Radar Altimeter):  Low-Resolution / SAR / SARIn modes  KU-band (single frequency, no radiometer)  POD from DORIS and laser ■Ocean data availability not confirmed yet, studies under way Thermal Radiator Magnetometer Star Trackers SIRAL Antennas Laser Retroreflector DORIS Antenna X-Band Downlink Antenna S-Band Communications Antenna

2nd GODAE Observing System Evaluation Workshop - June 2009 – J. Lambin 9 Jason-3 ■NOAA/EUMETSAT cooperation with CNES & NASA contributions  CNES in-kind contribution : Proteus platform, system engineering, and manpower equivalent to JASON/OSTM (i.e. about one third of European part of the program)  Launch : mid-2013 ■Mission design: Jason-2 like ■Pending approval (in December 2009) … and Jason-CS?

2nd GODAE Observing System Evaluation Workshop - June 2009 – J. Lambin 10 Surface Water & Ocean Topography (SWOT) Mission combining research needs associated to hydrology and oceanography : - mapping of water level for rivers, lakes, and oceans (including coasts) Principle : Wide-swath interferometric, Ka-band altimeter Recommended by the US Decadal Survey Submitted in the frame of the Cnes Scientific Prospective Seminar (march, 2009) Cooperation scheme : TBD (NASA/CNES/…) Phase 0 in 2007, pre-phase A & phase A in 2008/2009 Launch possible in ~2016

2nd GODAE Observing System Evaluation Workshop - June 2009 – J. Lambin 11 Conclusions ■There is a rich panel of missions under development or planning => let us wish they will all succed! ■Space agencies (NASA, CNES) tend to put as priority innovative missions  Promising in a long term perspective, but  Potential issues in the continuity of the long-term record  Some effort is required to secure the transition to operational agencies of already mature concepts ■Multiple missions decided/developed by multiple agencies/countries  Coordination not guaranteed, higher programatics risk  Data availability on a case-by-case basis  Efforts from CEOS (through NOAA and EUMETSAT) to improve altimetry mission coordination ■GODAE could (and should) be more vocal about their needs

2nd GODAE Observing System Evaluation Workshop - June 2009 – J. Lambin 12 TOPEX/POSEIDON (CNES/NASA) Launcher DORIS & POSEIDON Mission Center Reference mission Ocean Large scale Earth reference system SPOT2 (CNES) DORIS SPOT3 (CNES) DORIS SPOT4 (CNES) DORIS SPOT5 (CNES) DORIS Jason-1 (CNES/NASA) Satellite bus DORIS & POSEIDON Control & Mission Center ERS-1 (ESA) Altimeter algorithm ENVISAT (ESA) DORIS Altimeter Processing Archive & distrib. ERS-2 (ESA) experiment operational CRYOSAT2 (ESA) DORIS Jason-2 / OSTM (CNES/NASA/EUMETSAT/NOAA) Satellite bus DORIS & POSEIDON Control & Mission Center ALTIKA/SARAL (CNES/ISRO) Altimeter, radiometer, DORIS, Lra Process, archive & distrib. SALP : Altimetry and precise positioning service MERCATOR : assimilation, forecast CNES / SHOM / METEOFRANCE / IFREMER / CNRS / IRD PLEIADES (CNES) DORIS 2005 CRYOSAT (ESA) DORIS 2010 HY-2 (CNSA) DORIS CNES involvment in altimetry Complementing mission mesoscale, ice Sentinel-3A (ESA) DORIS