Satellite Altimetry Status

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Satellite Altimetry Status Products Part 1

• J. Lambin, CNES
• G. Dibarboure, CLS

2
Satellite altimetry users needs as seen by
space agencies

• One high accuracy reference mission
• TOPEX/Poseidon , Jason series (including Jason-3)
  gt 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 gt post-calibrations using
  reference mission, SSO OK
• Mesoscale oriented gt better spatial coverage,
  but longer cycles
• Future generation / alternatives
• Swath altimetry SWOT
• Constellations (Iridium-NEXT?)

3
Ocean Surface Topography Constellation Roadmap
21
Medium accuracy SSH from high-inclination
sun-synchronous orbit
ENVISAT ESA
GFO-FO NOAA
Swath altimetry from high-inclination orbit
(several orbit options)
Orbit to be assessed
High accuracy SSH from mid-inclination orbit
Jason-3 Europe/USA
Jason-1 Fr./USA
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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
• 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 J1J2EN
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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

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

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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
• 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
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Cryosat-2

• ESA mission, to be launched in Nov 2009
• Objective to determine fluctuations in the mass
  of the Earths 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

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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?
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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 gt 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
Reference mission Ocean Large scale
Complementing mission mesoscale, ice
Earth reference system
1990
experiment
ERS-1 (ESA) Altimeter algorithm
TOPEX/POSEIDON (CNES/NASA) Launcher DORIS
POSEIDON Mission Center
ERS-2 (ESA)
ENVISAT (ESA) DORIS Altimeter Processing Archive
distrib.
2000
Jason-1 (CNES/NASA) Satellite bus DORIS
POSEIDON Control Mission Center
HY-2 (CNSA) DORIS
2005
ALTIKA/SARAL (CNES/ISRO) Altimeter, radiometer,
DORIS, Lra Process, archive distrib.
Jason-2 / OSTM (CNES/NASA/EUMETSAT/NOAA) Satellit
e bus DORIS POSEIDON Control Mission Center
PLEIADES (CNES) DORIS
2010
CRYOSAT2 (ESA) DORIS
Sentinel-3A (ESA) DORIS
SALP Altimetry and precise positioning service
operational
MERCATOR assimilation, forecast CNES / SHOM /
METEOFRANCE / IFREMER / CNRS / IRD