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?)

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10 11 12 13 14 15 16 17 18 19 20 21 22

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 orbit Approved Planned/Pending approval Needed

Orbit to be assessed

Sentinel-3B, -3C, -3DSentinel-3A Europe

HY-2B, -2C, -2DHY-2A China

ERS-2 ESA

0908

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

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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

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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 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

MagnetometerStar Trackers

SIRAL Antennas

Laser Retroreflector

DORISAntenna

X-Band DownlinkAntenna

S-Band Communications

Antenna

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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 => 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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TOPEX/POSEIDON (CNES/NASA)

LauncherDORIS & POSEIDON

Mission Center

Reference missionOcean Large scale

Earth reference system

SPOT2 (CNES)DORIS

SPOT3 (CNES)DORIS

SPOT4 (CNES)DORIS

SPOT5 (CNES)DORIS

1990

2000

Jason-1 (CNES/NASA)Satellite bus

DORIS & POSEIDONControl & Mission Center

ERS-1 (ESA) Altimeter algorithm

ENVISAT (ESA)DORIS

Altimeter ProcessingArchive & distrib.

ERS-2 (ESA)

experiment

operational

CRYOSAT2 (ESA)DORIS

Jason-2 / OSTM (CNES/NASA/EUMETSAT/NOAA)

Satellite busDORIS & POSEIDON

Control & Mission Center

ALTIKA/SARAL(CNES/ISRO)

Altimeter, radiometer, DORIS, Lra

Process, archive & distrib.

SALP : Altimetry and precise positioning service

MERCATOR : assimilation, forecastCNES / SHOM / METEOFRANCE / IFREMER / CNRS / IRD

PLEIADES (CNES)DORIS

2005CRYOSAT (ESA)DORIS

2010

HY-2 (CNSA)DORIS

CNES involvment in altimetry

Complementing missionmesoscale, ice

Sentinel-3A (ESA)DORIS