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Report
Satellite Altimetry Status & Products – Part 1
J. Lambin, CNES
G. Dibarboure, CLS
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
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Ocean Surface Topography Constellation Roadmap
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Medium accuracy SSH from high-inclination sun-synchronous orbit
HY-2A China
HY-2B, -2C, -2D
Saral/AltiKa India/France
ERS-2 ESA
ENVISAT ESA
Sentinel-3B, -3C, -3D
Sentinel-3A Europe
CRYOSAT-2 ESA
GFO NOAA
GFO-FO NOAA
Swath altimetry from high-inclination orbit (several orbit options)
SWOT/WaTER-HM USA/Europe
Orbit to be assessed
Jason-CS successor Europe/USA
High accuracy SSH from mid-inclination orbit
Jason-3 Europe/USA
Jason-1 Fr./USA
Jason-CS/Jason-4 Europe/USA
Jason-2 Europe/USA
In orbit
Approved
Planned/Pending approval
2nd GODAE Observing System Evaluation Workshop - June 2009 – J. Lambin
Needed
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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
Jason-1 vs Jason-2 SSH differences
■ 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
2nd GODAE Observing System Evaluation Workshop - June 2009 – J. Lambin
DUACS map of SLA – J1+J2+EN
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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
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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
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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
geodetic orbit after 3 days
■ 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)
2nd GODAE Observing System Evaluation Workshop - June 2009 – J. Lambin
One day of the 14-day orbit
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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


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Star Trackers
Magnetometer
SIRAL
Antennas
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):
Thermal
Radiator
 Low-Resolution / SAR / SARIn modes
 KU-band (single frequency, no radiometer)
 POD from DORIS and laser
Laser
Retroreflector
DORIS
Antenna
S-Band
Communications
Antenna
X-Band
Downlink
Antenna
2nd GODAE Observing System Evaluation Workshop - June 2009 – J. Lambin
■ Ocean data availability not confirmed yet,
studies under way
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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
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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
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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
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CNES involvment in altimetry
experiment
Complementing mission
mesoscale, ice
ERS-1 (ESA)
Altimeter algorithm
ERS-2 (ESA)
ENVISAT (ESA)
DORIS
Altimeter Processing
Archive & distrib.
HY-2 (CNSA)
DORIS
Reference mission
Ocean Large scale
TOPEX/POSEIDON
(CNES/NASA)
Launcher
DORIS & POSEIDON
Mission Center
Jason-1 (CNES/NASA)
Satellite bus
DORIS & POSEIDON
Control & Mission Center
ALTIKA/SARAL
(CNES/ISRO)
Altimeter, radiometer,
DORIS, Lra
Process, archive & distrib.
Sentinel-3A (ESA)
DORIS
operational
Jason-2 / OSTM
(CNES/NASA/EUMETSAT/NOAA)
Satellite bus
DORIS & POSEIDON
Control & Mission Center
Earth reference system
1990
SPOT2 (CNES)
DORIS
SPOT3 (CNES)
DORIS
SPOT4 (CNES)
DORIS
SPOT5 (CNES)
DORIS
2000
2005
CRYOSAT (ESA)
DORIS
PLEIADES (CNES)
DORIS
CRYOSAT2 (ESA)
DORIS
2010
SALP : Altimetry and precise positioning service
MERCATOR : assimilation, forecast
CNES / SHOM / METEOFRANCE / IFREMER / CNRS / IRD
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