1. Sea Level_cci AGU 2014 J Benveniste 1, G Gilles 2, A Cazenave 3,4, M Ablain 2, J F Legeais 2, Y Faugère 2, B Lucas 5, S Dinardo 6, J A Johannessen 7, D Stammer 8, G Timms 9, P Knudsen 10, P Cipollini 11, M Roca 12, S Rudenko 13, J Fernandes 14, M Balmaseda 15, G Quartly 16, L Fenoglio-Marc 17, T Guinle 4, B Messignac 4 1. ESA, 2. CLS (France), 3. LEGOS (France), 4. CNES (France), 5. Deimos/ESA, 6. Serco/ESA, 7. NERSC (Norway), 8. University of Hamburg (Germany), 9. CGI (UK), 10. DTU (Danemark), 11. NOC (UK), 12. isardSAT (Spain), 13. GFZ (Germany), 14. FCUP (Portugal), 15. ECMWF (UK), 16. PML (UK), 17. TUD (Germany)

2. Sea Level_cci AGU 2014 J Benveniste 1, G Gilles 2, A Cazenave 3,4, M Ablain 2, J F Legeais 2, Y Faugère 2, B Lucas 5, S Dinardo 6, J A Johannessen 7, D Stammer 8, G Timms 9, P Knudsen 10, P Cipollini 11, M Roca 12, S Rudenko 13, J Fernandes 14, M Balmaseda 15, G Quartly 16, L Fenoglio-Marc 17, T Guinle 4, B Messignac 3,4 1. ESA, 2. CLS (France), 3. LEGOS (France), 4. CNES (France), 5. Deimos/ESA, 6. Serco/ESA, 7. NERSC (Norway), 8. University of Hamburg (Germany), 9. CGI (UK), 10. DTU (Danemark), 11. NOC (UK), 12. isardSAT (Spain), 13. GFZ (Germany), 14. FCUP (Portugal), 15. ECMWF (UK), 16. PML (UK), 17. TUD (Germany)

3. Sea Level_cci AGU 2014 Context UNFCCC Requirements to meet the needs of the CC community Objective: provide stable, long-term, satellite-based ECVs data products for climate modellers and researchers.

4. Sea Level_cci AGU 2014 Context UNFCCC Objective: To realise the best long term ECVs records the full potential of the long- term global Earth Observation archives from satellites (not just ESA but all sources via international collaboration) as a significant and timely contribution to the ECV databases required by UNFCCC. CCI PROGRAM

5. Sea Level_cci AGU 2014 :TOPEX/Poseidon What is in the CCI-sea level product? Based on satellite data from ESA, CNES, EUMETSAT, NASA, NOAA, US NAVY, ISRO Record available now Record available in Dec 2014 Record available in Dec 2015 2015

6. Sea Level_cci AGU 2014 CCI product: same approach as AVISO with different standards Level 0: Data acquisition Level 1: Raw telemetry Level 2: Altimetry data 1) instrumental errors 2) atmospheric propagation and perturbations 3) Geophysical corrections 4) POD Level 2: Altimetry data 1) instrumental errors 2) atmospheric propagation and perturbations 3) Geophysical corrections 4) POD Level 3: Cross calibration and Validation Level 4: Final products Same standards when possible Objective: get the best long-term trends and decadal variability possible.

7. Sea Level_cci AGU 2014 New instrumental correction for ENVISAT: GMSL trend more consistent between ERS-ENVISAT and Topex-Jason Global Mean Sea Level before CCI ERS + Envisat T/P+Jason Improvements of the sea level record for climate studies: on the GMSL Global Mean Sea Level after CCI ERS + Envisat T/P+Jason Mean Sea Level (mm) -4 +4 1993 2012 -4 +4 1993 2012 New wet troposphere corrections based on the GNSS path delays -0.2 +0.2 mm/yr Trends over 1993-2005 Sea Level_cci AGU 2014

8. Global mean sea level trendComparison with GRACE+ARGO CCI Global mean sea level Global mean sea level (average of AVISO, Colorado University, NOAA and GSFC data) Improvements of the sea level record for climate studies: Validation

9. Sea Level_cci AGU 2014 ESA Sea_Level_cci: Uncertainties Uncertainty in GMSL trend: ±0.5 mm/yr over 1993-2010 and ±0.36 mm/yr over 2000-2010 Uncertainty in GMSL variations (available in the next release): ~±2. mm

10. Sea Level_cci AGU 2014 ESA Sea_Level_cci: Uncertainties Uncertainties * More details to the satellite-based component of the “Implementation Plan for the Global Observing System for Climate in Support of the UNFCCC (2010 Update)” GCOS-154, december 2011)

11. Sea Level_cci AGU 2014 Link: http://www.aviso.altimetry.fr dataset: daily, along track or gridded (¼°x¼°) Many products: mono and multi-mission near RT or delayed (with update ~5month) objectives: optimised for mesoscale and ocean circulation. Provide frequently updated data and near RT products, high accuracy GMSL… common applications: sea level studies at monthly to multi-decadal time scales, ocean circulation studies operationnal oceanography, assimilation in reanalysis(1993-2013). Link: http://www.esa-sealevel-cci.org dataset: monthly, gridded (¼°x¼°) 1 product: multi-mission, delayed (with update ~1yr, starting in Dec 2014) objective: optimised for long-term trends and decadal variability common applications: sea level studies at interannual to multi-decadal time scales, trend studies, assimilation in long term reanalysis (1958-2013). different products for different needs

12. Sea Level_cci AGU 2014 Sea Level ECV products The Sea Level ECV (V1.1) covered the period [1993-2010]. This was extended on 12 December 2014 over the [1993, 2013] period During phase 2 : the length of time series will be regularly updated and lengthened in order to reach as close as possible the present days and to better answer the user needs A full reprocessing is planned in June 2016 (  V2.0 ) over the period [1993,2014] 2014 2015 V1.1 SL ECV Extension [2011-2013] 2016 V2.0 SL ECV Extension [2015] V1.1 SL ECV Extension [2014] V2.0 SL ECV Reprocessing [1993-2014] Phase 2 on-going work

13. Sea Level_cci AGU 2014 Sea Level ECV products SLCCI ECV release : V1.1 available via: http://www.esa-sealevel-cci.org/http://www.esa-sealevel-cci.org/ Please contact us: info-sealevel@esa-sealevel- cci.orginfo-sealevel@esa-sealevel- cci.org ¼° Gridded Monthly mean

14. Sea Level_cci AGU 2014 Sea Level ECV products SLCCI ECV release : V1.1 available via: http://www.esa-sealevel-cci.org/http://www.esa-sealevel-cci.org/ Please contact us: info-sealevel@esa-sealevel-cci.org ¼° Gridded Monthly mean

15. Sea Level_cci AGU 2014 Sea Level ECV products For the 2016 reprocessing (V2.0), several improvements are foreseen :  Integration of new altimeter missions: Cryosat-2 (April 2010), SARAL/Altika (February 2013), Sentinel-3 (end 2015) and Jason-3 (April 2015)  Development, evaluation and selection of new sea level corrections and algorithms in order to have state of the art consistent ‘climate’ standards: use of new atmospheric reanalyses, new orbit solutions, new ocean tidal models, …  Improvement of sea level calculation in coastal areas  Improvement of sea level calculation in Arctic ocean : increase data coverage near-by and under sea-ice

16. Sea Level_cci AGU 2014 External users have also uploaded the SL-cci products :  NASA Earth Observatory (USA), U. Colorado (USA), University of Edinburgh (UK), Mercator Océan (France), IMEDEA (Spain), … Products are used by the climate modelling/validation sub-group:  UoH (D.Stammer) : sea level ECV assimilation in model (along-track product)  ECMWF (M. Balmaseda) : sea level ECV assimilation in model (along-track product) and also the Global MSL indicator  NERSC (J. Johannessen) : comparison of sea-level ECV (grids) with model outputs  LEGOS (A. Cazenave, B. Meyssignac) : use of sea-level ECV (grids + indicator) for closure budget studies Increase the promotion and enhance the international coordination Assessment by CRG group Phase 2 on-going work

17. Sea Level_cci AGU 2014 Spatial ScalesTemporal Scales User Requirements Altimetry errors CCI products Global Mean Sea Level (10-day averaging) Long-term evolution (> 10 years ) 0.3 mm/yr< 0.5 mm/yr Inter annual signals (< 5 years) 0.5 mm over 1 year < 2 mm over 1 year Periodic signals (Annual, 60-days,…) Not defined Annual < 1 mm 60-day < 5 mm Regional Mean Sea Level (2x2 deg boxes and 10-day averaging) Long-term evolution (trend) 1 mm/yr< 3 mm/yr Inter annual signals (> 1 year) Not DefinedNot evaluated Periodic signals (Annual, 60-days,…) Not Defined Annual < 1mm 60-day < 5 mm During phase 1 : Altimetry measurement errors at climate scales have been characterized (Ablain et al, 2012) Sea-level error characterisation

18. Sea Level_cci AGU 2014 Information requested by users or climate modellers :  1) Refine the error budget at interannual time scale Spatial ScalesTemporal Scales Altimetry errors [1993-2002] Altimetry errors [2003,2013] Global Mean Sea Level (10-day averaging) Long-term evolution (> 10 years ) 0.7- 0.8 mm/yr< 0.5 mm/yr Inter annual signals (< 5 years) < 5 mm over 1 year < 2 mm over 1 year Periodic signals (Annual, 60-days,…) Annual < 1 mm 60-day < 5 mm Annual < 1 mm 60-day < 2 mm Regional Mean Sea Level (2x2 deg boxes and 10-day averaging) Long-term evolution (trend) < 4 mm/yr< 2 mm/yr Inter annual signals (> 1 year) Not evaluated Periodic signals (Annual, 60-days,…) Not evaluated Phase 2 on-going work Sea-level error characterisation

19. Sea Level_cci AGU 2014 Information requested by users or climate modellers :  2) Define the GMSL error or confidence envelope Phase 2 on-going work Sea-level error characterisation

20. Sea Level_cci AGU 2014 Information requested by users or climate modellers :  2) Define the GMSL error or confidence envelope Phase 2 on-going work Sea-level error characterisation

21. Sea Level_cci AGU 2014 Information requested by users or climate modellers :  3) Provide regional sea level trend error maps Sea-level error characterisation 0 mm/yr 2 mm/yr Phase 2 on-going work

22. Sea Level_cci AGU 2014 Sea_Level_cci Phase 2 The CCI phase I achievements have encouraged the continuation of the work by launching the phase II of the program. This new phase, started in 2014 for 3 additional years, will allow us to explore the new areas of improvement which arose in phase I. Evolutions of the algorithms are central to the project since they affect the physical content of the Sea Level CCI ECV products. The strategy is thus to refine the user requirements and to focus on the improvement of the altimeter corrections which constitute the most important sources of errors with respect to the climate scales. The main challenges are: Altimeter and radiometer processing: use a multi-mission instrument expertise to enhance all the altimeter and radiometer calibration accuracy. Improved orbits: provide the best homogeneous solution for all missions. Sea Level corrections: homogeneous and stable time series using, for example, the most recent reanalyzed models. Arctic region: reduce the altimetry errors at high latitudes. Coastal areas: improve the sea level near the coasts. All these developments will provide us with the opportunity to increase the synergy between the altimeter experts and other communities, particularly the atmosphere and sea ice communities.

23. Sea Level_cci AGU 2014 Sea_Level_cci Phase 2 A specific task will be dedicated to the assessment of the ECV products by Climate Research Group: this will first be done through assimilation and comparison with ocean models outputs. The error of the products will be characterized through sea level closure budget analyses and international inter comparison exercises. This work will be performed keeping in mind the phase I achievements. This will be the opportunity to increase the link with other ECVs (SST, Sea Ice, Ice Sheets). The new ECV versions will be distributed on request to users. The 2011-2013 Extension to the 1993-2010 series has been released last week! SLCCI ECV release : V1.1 available via: http://www.esa-sealevel-cci.org/http://www.esa-sealevel-cci.org/ Please contact us: info-sealevel@esa-sealevel-cci.orginfo-sealevel@esa-sealevel-cci.org

24. Sea Level_cci AGU 2014 Sea_Level_cci Phase 2 J Benveniste 1, G Gilles 2, A Cazenave 3,4, M Ablain 2, J F Legeais 2, Y Faugère 2, B Lucas 5, S Dinardo 6, J A Johannessen 7, D Stammer 8, G Timms 9, P Knudsen 10, P Cipollini 11, M Roca 12, S Rudenko 13, J Fernandes 14, M Balmaseda 15, G Quartly 16, L Fenoglio-Marc 17, T Guinle 4, B Messignac 4 1. ESA, 2. CLS (France), 3. LEGOS (France), 4. CNES (France), 5. Deimos/ESA, 6. Serco/ESA, 7. NERSC (Norway), 8. University of Hamburg (Germany), 9. CGI (UK), 10. DTU (Danemark), 11. NOC (UK), 12. isardSAT (Spain), 13. GFZ (Germany), 14. FCUP (Portugal), 15. ECMWF (UK), 16. PML (UK), 17. TUD (Germany)