Sea Level Algorithm Selection Meeting

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1 ESA Climate Change Initiative Sea Level CCI project Sea Level Algorithm Selection Meeting

2 INTRODUCTION Outline Objectives and organisation of the meeting Brief overview of the Sea Level CCI projet G. Larnicol/Y. Faugère (CLS) Presentations are available here : ftp://ftp.esa-sealevel-cci.org/documents/meeting/selectionmeeting/ Login: slcci_cls / Password: cls2011

3 Why are we here today? Provide recommendations for the selection of the algorithms that will be used for the generation of the Sea Level ECV products (ESA Sea Level CCI project) Identify way of improvements and ideas for future investigations

4 Why are we here today? ESA Sea Level CCI project User requirements Algorithms Development Algorithms Selection ECV Production ECV Assessment Round-robin exercise validation reports production Selection meeting

5 Selection meeting 2 days Review of each algorithms (chair by resp from EO team) - Time for presentation of main results and proposition of recommendations - Time for discussion about recomm & open issues Introduction - Intro & SL CCI project - CCI program (Jérôme) - Science challenges (Anny) - RoundRobin approach (Michael) 7 sessions - Orbit - Ionospheric correction - Instrumental corrections - Sea state bias - Wet tropospheric correction - Atmospheric corrections -Merging altimeter missions - Tidal corrections 2 sessions - Coastal - High latitudes Wednesday Thursday Friday Conclusion and Final Recomm Sea Level CCI Selection Meeting 2 nd - 4 th May 2012, Toulouse LEGOS

6 Selection meeting 2 days 10 experts «I would nonetheless like to stress that this event is a very good example of how CCI should be working, and I agree that, the international participation in the sea-level algorithm selection selection is particularly significant. It is in everyone's interest to feed all the lessons learned from this exercise into the future set-up of CCI.» Mark Doherty Thanks for your involvment C. K. Shum (OSU) S. Nerem (CCAR) P. Woodworth (NOC) J. Willis (JPL) P. Y. Le Traon (Ifremer) R. Scharroo (Altimetrics LLC) N. Picot (CNES) S. Brown (NASA) S. Vignudelli (CNR) R. Ponte (AER)

7 Selection meeting 2 days 10 experts 1 SL CCI team LEGOS: Anny, Hindu, FLorent CLS:Michael,Yannice,Pierre,Ngan, Loren, Sylvie, Bruno, Claire, Isa,... GFZ: Sergei DTU: Ole IsardSat: Roca UoP: Joana, Alexandra UoH: Detlef Logica: Gary, Ed NOCS: Paolo (excused) ECMWF: Magdalena (excused) NERSC: Johnny (excused) Sea Level CCI Selection Meeting 2 nd - 4 th May 2012, Toulouse LEGOS

8 Selection meeting 2 days 10 experts 1 SL CCI team 2 ESA representatives J. Benveniste (TO) S. Dinardo 1 CMUG representative T. Phulpin (Meteo France)

9 Selection meeting 2 days 10 experts 1 SL CCI team 2 ESA representatives 1 CMUG representative several guests T. Guinle, J Lambin, L Cerri, P Escudier (CNES) J Dorandeu (Mercator Ocean) B Messygnac (LEGOS)

10 Selection meeting 2 days Executive summary reports 10 experts 1 SL CCI team 2 ESA representatives 1 CMUG representative several guests materials The validation reports Yannice s From 14th march Sea Level CCI Selection Meeting 2 nd - 4 th May 2012, Toulouse LEGOS

11 Selection meeting 2 days 10 experts 1 SL CCI team 2 ESA representatives 1 CMUG representative several guests materials Coffee breack, cocktail & dinner Sea Level CCI Selection Meeting 2 nd - 4 th May 2012, Toulouse LEGOS

12 Selection meeting 2 days 10 experts 1 SL CCI team 2 ESA representatives 1 CMUG representative several guests materials We have all the ingredients to have a rich and fruitful Selection meeting Coffee breack, cocktail & dinner Sea Level CCI Selection Meeting 2 nd - 4 th May 2012, Toulouse LEGOS

13 Logistics Coffe break & Thursday lunch in Coriolis room Cocktail on Wednesday at 6:30PM in Coriolis room Thursday Dinner «Tables d hôtes Chez Navarre» in toulouse city center meeting at 19:30PM Wifi available : login/ passwd Taxi: we will centralize Picture

14 The Sea Level CCI project Sea Level CCI Selection Meeting 2 nd - 4 th May 2012, Toulouse LEGOS

15 Climate Change Initiative First phase of ESA CCI scientific user consultation, specifications Start in mid-2010, 3 years projects 13 ECV projects covering ocean, land, & atmosphere Ocean: sea level, SST, ocean colour, sea ice Land: fire, land cover, glaciers, ice sheet, soil moisture Atmosphere:aerosol, cloud, ghg,ozone 1 project with Climate Modeling User Group (ECWMF, UkMet, MPI, MF)

16 Climate Change Initiative Jerome s presentation : Overall CCI programme Links with other international initiatives Current status of the programme

17 Sea Level CCI project Started 15th july 2010 Prime: CLS + 10 partners +CNES contribution Science leader: Anny Cazenave (LEGOS) Project manager: Gilles Larnicol (Y Faugère) (CLS) Earth Observation team: Michael Ablain (CLS) IsardSat, DTU, GFZ, UoP, NOCS, LEGOS + CNES Climate Modeling group: Detlef Stammer (UoH) NERSC, ECMWF System engineering team: Gary Timms (LOGICA) CLS

of an ECV product using new algorithms -2- Product Assessment and enhance the link with climate community -3- Provide system

18 Organisation WP1: Requirements analysis & Products specification WP6: Project Managemet WP2: Algorithm developement, intercomparison & selection WP3: System prototyping & ECV Sea Level production WP4: Validation & user Assessment -1- Production of an ECV product using new algorithms -2- Product Assessment and enhance the link with climate community -3- Provide system requirements for future operational activities WP5: System specification More information on the project at

19 Sea Level ECV production The context To develop, test and select the best algorithms and standards in order to produce, within an R&D context, high quality sea level products for climate applications Algorithms Development Algorithms Selection ECV Production Done by each EO partner Centralised Round Robin Exercise (CLS) Demo/scientific product We are not exhaustive: - we do not address all issues for all missions - we will try to produce a data set as long as possible ensuring a maximum of consistency of the standard used for each missions used Full reprocessing and operational ECV products generation will be done in the frame of Phase 2 of CCI.

20 Sea Level ECV production The context To develop, test and select the best algorithms and standards in order to produce, within an R&D context, high quality sea level products for climate applications Algorithms Development Algorithms Selection ECV Production Done by each EO partner Centralised Round Robin Exercise (CLS) Demo/scientific product Two main priorities has been defined: - Develop algorithm dedicated for Climate applications - Optimise the use of ESA missions (ERS-1/2, ENVISAT)

Algorithm development Extensive work on algorithm development and cross comparison 50 algorithms cross compared over 5 altimetry missions

21 Algorithm development Extensive work on algorithm development and cross comparison 50 algorithms cross compared over 5 altimetry missions in 8 RRDP in 8 RRDP in 11 RRDP +4 multimission RRDP in 9 RRDP in 21 RRDP Sea Level CCI Selection Meeting 2 nd - 4 th May 2012, Toulouse LEGOS

An existing capacity... The LEGOS/CNES/CLS group in Toulouse have already demonstrated its ability to produce ECVs like-products on a regular basis.

22 An existing capacity... The LEGOS/CNES/CLS group in Toulouse have already demonstrated its ability to produce ECVs like-products on a regular basis. AVISO products already delivered to international organization and Climate research community (CEOS, OOPC, EEA, IPCC) The project is based on this existing group and infrastructure (SALP) which will be at the core of the project The project give us the opportunity to improve the collaboration at the European level (EO team)

23 Round Robin exercise 1 Algorithms Development 2 Algorithms Selection 3 ECV Production Round-robin exercise validation reports production Selection meeting 1 Each partner of the EO team develop algorithms 2 Setting up of the Round robin exercice where algorithms are compared through common validation plan and tools 3 Production of the SL ECV thanks to the SALP infrastructure

24 Climate Users Requirements User requirements Algorithms - J Johannessen Algorithms (NERSC) lead with ECV Anny, Detlef, ECV Michael, Development Yannice, Gilles Selection Production Assessment - UR have been refined in the frame of the project and ESA used them as a contribution for the new version of the GCOS requirements Variable/parameter Requiremen t number Horizontal resolution Temporal resolution Accuracy Stability Global Mean sea level Regional sea level Mesoscale 2 Time Mean (Mean Dynamic Topography) UR-SLCCI- SPC-01 UR-SLCCI- GEN-02 UR-SLCCI- GEN-03 UR-SLCCI- GEN-04 Global mean NA 2-4 mm over an orbital cycle km week 1 cm over a grid mesh of km Long term drift < 0.3 mm/y Annual time scale < 0;5 mm/y over 1é months < 1 mm/y over a frid mesh of km 15 km daily 0,5 cm No strong requirements 25 km NA but covered [ ] period TBD NA

Planning AR1 OSTST 2011 Algo Selection Meeting 2012 20

Recomm for algo ECV production ECV products Sea Level

25 Planning AR1 OSTST 2011 Algo Selection Meeting years of altimetry Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul aug sep oct nov dec Algo. dev. RRDP Production Validation reports Selection process Recomm for algo ECV production ECV products Sea Level CCI Selection Meeting 2 nd - 4 th May 2012, Toulouse LEGOS User Assessment

26 The Sea Level CCI products Fundamental Climate Data Record (FCDR ): The FCDR is a mono-mission product generated from an altimeter level-2 product. It contains the along-track SSH estimates at 1Hz over ocean with a quality control indicator to remove spurious measurements. It also contains the altimeter standards applied in the SSH calculation, such as the geophysical corrections, the mean sea surface, etc. Product Name FCDR Scientific content Along track SSH and SSH component Format Netcdf CF (Consistent within CCI project) resolution 1 Hz/ 6km period Jan 1993-Oct 2010

27 The Sea Level CCI products Essential Climate Variable (ECV) products : The ECV is a multisatellite merged producthas the following content: Time data series of SLA: This corresponds to the SLA grids calculated after merging all the altimetric mission measurements together into monthly grids with a spatial resolution of 1/3 of degrees. Oceanic indicators: This corresponds to static files over the whole altimeter period describing the evolution of the SLA grids just previously described (global MSL, regional MSL) Errors of oceanic indicators Name Scientific content Format resolution FCDR Map Time data series of SLA Oceanic indicators Errors of oceanic indicators Netcdf (Consistent within CCI project) 1/3 degree / monthly period Jan 1993-Oct 2010

28 User Assessment ECV Products will be available by September additional access point through CCI? Task planned inside the project to evaluate from the users point of view the SL ECV product -1- a round-robin will be performed following the validation plan defined for each individual algorithms (CLS) SL ECV product will be compared to the AVISO reference -2- Involvement of users from ocean modelling (UoH, NERSC, ECMWF) (dedicated task) and climate communities (LEGOS) Assessment through data assimilation&validation studies and through data analysis like closure budget (LEGOS) Sea Level CCI Selection Meeting 2 nd - 4 th May 2012, Toulouse LEGOS

29 Future System Requirements Provide requirements for the future operational system (Logica, CLS) Context: Phase 1 aims to define and validate innovative approaches for continous generating and updating of ECVs (phase 2) Initial questions with respect to the phase 2: - What are the commonalities between the ECVs? - How many 1, 3, 11 systems? - How long an ECV products is relevant? 4 years, 2 years? - How to manage interface/planning with other contributing projects, in particular reprocessing projects? After one and half year, other questions and outcome appear: - How to maintain a close link between climate&ocean user community and EO team and in particular to maintain a close loop able to implement new/updated algorithms? - How to stick to the actuality? (REP has been done every 2 years, link with Delayed Time and Near Time products) Sea Level CCI Selection Meeting 2 nd - 4 th May 2012, Toulouse LEGOS

Altimetry constellation Jason-1 has suffered 3 safe hold modes, inducing mission

coming days ENVISAT loss of communication 8th april end of mission Cryosat 2 has

are a reminder of the current fragility of the altimetry constellation.

30 Altimetry constellation Jason-1 has suffered 3 safe hold modes, inducing mission unavailability between 16 th -29 th Feb and since 3 rd March recovering in the coming days ENVISAT loss of communication 8th april end of mission Cryosat 2 has been integrated (6th feb) for near real time applications (DUACS/SLTAC) The events are a reminder of the current fragility of the altimetry constellation. We will enter into a degradred and frail period both for mesoscale observability but also for climate applications

progress report: Q2 2011

Consortium Members ESA Sea level CCI Quarterly progress report: Q2 2011 Reference: Nomenclature: CLS-DOS-NT-10-322 SLCCI-QPR-006 Issue: 1. 0 Date: Jul. 4, 11 CLS-DOS-NT-10-322 SLCCI-QPR-006 V 1.0 Jul.