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GLORYS2: A Global Ocean Reanalysis (1992-Present)

GLORYS2 is a global ocean reanalysis project providing detailed ocean simulations supported by GMMC, focused on improving oceanographic data quality. The project overview, system details, outcomes, and future perspectives are discussed.

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GLORYS2: A Global Ocean Reanalysis (1992-Present)

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  1. GLORYS2: A Global ocean reanalysis of the period 1992-present N. Ferry, B. Barnier, L. Parent, G. Garric, C. Bricaud, C-E Testut, O. Le Galloudec, J-M Lellouche, E. Greiner, M. Drevillon, E. Rémy J-M Molines, C. Cabanes LEGI, Mercator Océan, Coriolis

  2. Outline Introduction: - GLORYS project overview - European context GLORYS2 : an eddy permitting (1/4°) global ocean reanalyses of the « altimetric era » - reanalysis system overview - results GLORYS / MyOcean reanalysis meeting (June 2011): outcome Conclusions and perspectives

  3. 1. Introduction

  4. GLORYS project: National level GLORYS: GLobal Ocean ReanalYses and Simulations • French Reanalysis project, supported by GMMC (Mercator, Coriolis). PI: B. Barnier • main partners: LEGI, LPO, LOCEAN, CNRM, CORIOLIS, MERCATOR • project started at national level in 2008 • ARGO era reanalysis (2002-2008) produced in 2009 : GLORYS1V1 Objectif en 2011: • Achever la production de GLORYS2V1 (1993-2009) • Valider GLORYS2V1 et le run de reference MJM95 selon le protocole de validation commun MyOcean • Distribuer GLORYS2V1 et MJM95 • Quels défis pour les réanalyses ?  organisation d’un meeting réunissant les utilisateurs et les producteurs de réanalyses océaniques.

  5. GLORYS: different Streams Number of Obs. / 7 days GLORYS-1 T/S prof.: 2000~4500 SST: 0,5°x0,5°  0,1°x0,1° SLA: 3~4 satellites Stream1: 2002-2008“ARGO” GLORYS-2 T/S prof.: ~1000 SST:1°x1° SLA: 2~3 satellites Stream2: 1993-2007 “altimetry” 1992 2002 NOW GLORYS1V1: produced and delivered to users early 2009 GLORYS2V1: produced and delivered to users early 2011

  6. Global ocean reanalyses at EU level MyOcean project: www.myocean.eu.org WP4:  Global ocean reanalysis production & assessment Target: eddy permitting (1/4) global ocean reanalyses Basic ingredients: • NEMO3 Ocean code, tuned for reanalyses, provided by CNRS • ERA Interim forcing • Reprocessed historical observations provided by TACs • Different data assimilation methods • Ocean reanalyses: Ocean simulations constrained by reprocessed obs. CMCC, Mercator, U. Reading • Ocean free simulation: CNRS • Ocean state estimation based on observations only: CLS  GLORYS reanalyses

  7. Global ocean reanalyses at EU level MyOcean project: www.myocean.eu.org Within WP4:  Global ocean reanalysis production & assessment Two reanalysesversions are planed: V1 reanalysis:  “June 2011” V2 reanalysis:  “beginning 2012” (improved V1) delivered products : monthly fields, T, S, U, V, SSH, Sea Ice (conc., thickness, velocity)  Documentation describing the reanalysis (strategy, implementation) • Common CA/VAL protocol for reanalyses evaluation and assessment.

  8. 2. GLORYS2V1: reanalysis system overview

  9. GLORYS2: reanalysis system overview Requirements for a global ocean/sea ice reanalysis • Global ocean/sea-ice « eddy-permitting »  circulation model: ORCA025.L75 - NEMO OGCM (Ocean: OPA, sea-ice: LIM2_EVP) - Configuration set up by DRAKKAR consortium (Barnier et al, 2006, Drakkar group, 2007). • Data assimilation system - Adapted from operational SAM systems used by MERCATOR-Ocean for operational forecasts - SEEK Filter • A delayed-time quality-controlled observations for assimilation - In-situ: CORA data base (Coriolis data center) - Altimetry: AVISO data base (CLS) - SST maps

  10. Model: DRAKKAR ORCA025 configuration NEMO3.0/3.2 OGCM + LIM2 EVP Sea-Ice model: Resolution: - Global 1/4° ORCA-type grid (1442x1021 grid points) - 75 vertical levels from 1 m at the surface to 200 m at the bottom for GLORYS2 Initialization: December 1991 - Levitus 1998 climatology + Sea-Ice Concentration from NSDIC Bootstart products Parameterizations: Filtered free surface, Partial step, Energy and Enstrophy conserving advection scheme, Isopycnal diffusion for tracers, Biharmonic for momentum, TKE turbulence scheme Atmospheric forcing: - Bulk CORE Formulation (Large&Yeager, 2004) - ERA-Interim reanalysis products: 3 hourly for turbulent fluxes Daily for radiation (analytical diurnal cycle for solar) In house correction of the radiation based on GEWEX satellites fluxes products.

  11. correction of ERA-Interim radiative fluxes SST spatial errors structures SST (2002) model – RTG Downward SW Flux 2002 ERAinterim - GEWEX method to correct SW, LW Large Scale ERAinterim Fluxes with GEWEX

  12. ERAInterim : (monthly running mean) daily mean Climatology x Daily Climatology of corrective factor Daily ERAInterim field: large scale Satellite Obs : (monthly running mean) daily mean Climatology + Daily Corrected ERAInterim: large scale Daily ERAInterim field: small scale Daily Corrected ERAInterim field Method of correction • The correction is local, (i,j) grid point. • Large scales correction only. • Gewex climatology : 1999-2006; Indian Gap before. • Gewex [40S-40N] : -3% SW and -6% LW (as Large & Yeager 2004 for ISCCP) • GPCPV2.1 Climatology:1997-2008. • No correction northward 65N. • No correction for ERAinterim climatology values less than 1 unit (W.M-2 or mm.day-1). • No change of interannual signal. • No change of synoptic patterns (cyclones). • The method can be applied outside the satellite period.

  13. Correction of SW & LW ERAI ERAI/GEWEX Mean SST bias with SST RTG ERAI/SW&LW corrected • Large improvement with Gewex data • Same solution with corrected ERAinterim SW & LW fluxes • Errors remains in upwellings & large mesoscale activity areas. FLUX ERA-Interim corrigés: utilisés à Mercator, LEGI, CNRM, IC3.CAT

  14. GLORYS: DATA ASSIMILATION SCHEME DATA ASSIMILATION SYSTEM: SAM2v1, SEEK formulation SEEK Filter : - Innovation is calculated at the First Guess at Appropriate Time (FGAT) approximation - Control vector comprises the barotropic height, T, S, U and V - Background error covariance calculated from an ensemble of 3D anomaliesfrom a reference simulation • Adaptive error variance is consistent with innovation vector (a posteriori diagnostic) • The SEEK filter is weakly sensitive to the number of obs. to assimilate 3D-VAR Bias correction: for T and S Incremental Analysis Updates (IAU): inserting increments over all model time steps  smooth trajectory

  15. Delayed time observations for data assimilation Assimilated data : Along track DT SLA (SSLATO/DUACS) : Jason-1, Jason-2, Envisat, GFO, ERS1, ERS2, Topex/Poseidon

  16. Delayed time observations for data assimilation Assimilated data : Along track DT SLA (SSLATO/DUACS) : Jason-1, Jason-2, Envisat, GFO, ERS1, ERS2, Topex/Poseidon Reynolds AVHRR-only 0.25° SST,

  17. Delayed time observations for data assimilation Assimilated data : Along track DT SLA (SSLATO/DUACS) : Jason-1, Jason-2, Envisat, GFO, ERS1, ERS2, Topex/Poseidon Reynolds AVHRR-only 0.25° SST, in situ temperature & salinity profiles (Argo network + Xbts,CTDs, etc..) : CORA2.3 data base

  18. 2. GLORYS2V1 reanalysis : results

  19. Reanalysis validation strategy Validation protocol for reanalyses :  MERSEA-GODAE metrics,  CLIVAR/GSOP diagnostics,  MyOcean quality control for operational systems adapted for reanalyses 6 types of diagnostics: CLASS1: computations are done on the model native grid. CLASS2: comparison of reanalysis products moorings, tide gauges and indexes (e.g. Nino boxes) comparisons CLASS3: Mean and variability of integrated quantities like transports (volume, heat, freshwater), sea ice extent, global/regional averages of various parameters (SST, SLA, sea ice concentration, …) CLASS4 : collocation of observation with model DATA ASSIMILATION DIAGNOSTICS: innovation statistics. EOFs analysis

  20. Results: GLORYS2V1 reanalysis : 1992-2009 ARGO is getting in Data assimilation diagnostics for T Global misfit average Global misfit RMS RMS is stable No BIAS

  21. GLORYS2V1 reanalysis results Data assimilation monitoring : SLA RMS ~7cm No BIAS 1992 2009

  22. GLORYS2 REFERENCE: MJM95 Results: GLORYS2V1 reanalysis : 1992-2009 CLASS1 metric - difference with climatology SST (0.5 m depth): difference with Levitus climatology

  23. GLORYS2 REFERENCE: MJM95 Results: GLORYS2V1 reanalysis : 1992-2009 CLASS1 metric - difference with climatology Temperature (at 100 m depth): difference with Levitus climatology

  24. GLORYS2 REFERENCE: MJM95 Results: GLORYS2V1 reanalysis : 1992-2009 CLASS1 metric - difference with climatology Salinity (at 0.5 m depth): difference with Levitus climatology

  25. GLORYS2 REFERENCE: MJM95 Results: GLORYS2V1 reanalysis : 1992-2009 CLASS1 metric - difference with climatology Salinity (at 100 m depth): difference with Levitus climatology

  26. Results: GLORYS2V1 reanalysis : 1992-2009 Ocean Heat Content 0-700m Levitus et al., GRL 2005 1022 J GLORYS2V1

  27. Results: GLORYS2V1 reanalysis : 1992-2009 Ocean Heat Content 0-700m GLORYS2V1 reanalysis Observations only GLORYS2V1 Lyman et al. 2010 1992 2009

  28. Results: GLORYS2V1 reanalysis : 1992-2009 Ocean Heat Content 0-700m MJM95 reference simulation Observations only Lyman et al. 2010 1992 2009

  29. Results: GLORYS2V1 reanalysis : 1992-2009 Ocean global heat budget [0-2000m] global mean temperature GLORYS2V1 Levitus 1998 Climatology Mean temperature trend = + 0.5 W/m2 1992 2009

  30. Results: GLORYS2V1 reanalysis : 1992-2009 SST trends ___ GLORYS: 0.10°C/decade - - - OBS. : 0.17°C/decade

  31. Mean sea level rise 2.8 mm/year Results: GLORYS2V1 reanalysis : 1992-2009 Sea level rise Obs. (Altimetry)

  32. SEA ICE EXTENT INTERANNUAL ANOMALIES Correlation = 0.9 Results: GLORYS2V1 reanalysis : 1992-2009 Arctic Sea Ice: Ice extent

  33. Results: GLORYS2V1 reanalysis : 1992-2009 Arctic Sea Ice Extent: September 1996 maximum

  34. CLASS1 metric - difference with climatology Arctic Sea Ice Concentration

  35. Results: GLORYS2V1 reanalysis : 1992-2009 Arctic Sea Ice Extent: September 2007 minimum

  36. Results: GLORYS2V1 reanalysis : 1992-2009 CLASS1 metric - difference with climatology SVP drifter velocities are biased Grodsky et al. GRL 2011 15 m zonal velocity Under estimation of surface velocities Still major flaws in the representation of equatorial undercurrents (the FREE RUN is far better)

  37. Results: GLORYS2V1 reanalysis : 1992-2009 CLASS2 metric – local comparison with independent data GLORYS2 Comparison with Tide Gauges: GLORYS1

  38. RAPID-MOCHA measurements GLORYS reanalysis = in situ observations (after, Bryden et al., 2005) Results: GLORYS2V1 reanalysis : 1992-2009 Maximum Atlantic MOC at 26.5°N 20 10 20 10

  39. Results: GLORYS2V1 reanalysis : 1992-2009 Quality Control on in situ data performed in GLORYS reanalysis: Help to improve delayed time in situ data bases “bad” Temp. profiles in 2009 “bad” Salinity profiles in 2009

  40. Results: GLORYS2V1 reanalysis : 1992-2009 Quality Control on in situ data performed in GLORYS reanalysis: Help to improve delayed time in situ data bases Obs. CLIM FCST Obs. CLIM FCST T profile innovation innovation S profile

  41. GLORYS users > 40 users, data volume provided > 16 TB several research areas and application fields: • Biogeochemical modelling (LSCE, Mercator) • Ecosystem modeling (CLS/MEMMS) • Sea Ice (LPO, Mercator) • TIWs (LEGOS) • pCO2 (NIES Japan, Bjerknes CCR) • Ocean circulation estimation and validation (CLS, SHOM) • Ocean Thermal Energy Conversion (EDF, Mercator) • Boundary / Initial conditions for regional modeling (CNRM, Infocean) • Mean Dynamic Topography inter comparisons (CLS, China) • MOC, MHT (RSMAS, UFRPE, CLS, Mercator) • South Atlantic circulation (NOAA) • Climate indexes, trends (IMEDEA, Spain) • Global ocean Mass budget (EOST/IPGS, NASA/GSFC) • object / animal drift (CLS, LPO, U. Texas, U. Hawai) • Hurricane (LEGI, CERSAT) • …

  42. 3. GLORYS / MyOcean reanalysis meeting in June 2011

  43. GLORYS/MYOCEAN Workshop en Juin 2011 : Objective: The objective of this workshop is to gather the users and the producers of these reanalysis products, as well as other reanalysis products (e.g. MyOceanWP4, etc) in order : • to assess the scientific value of the reanalyses, • to identify and prioritize ways of improvements of those products, • to prepare the next generation of reanalyses • 2-day meeting • ~ 30 participants • 17 oral presentation • discussions

  44. Conclusions from GLORYS/MYOCEAN Workshop: - Extend the reanalysis in the past (1979  present) - Assimilation of Sea-Ice data (concentration and velocity). - Improving of ORCA025 model (including tides). - Improving forcing (inter-annually varying runoffs, flux correction through data assimilation). - search for additional assimilation data (Tide gauges, SSS from SMOS, Aquarius, GRACE, etc.). - Links with the Green Ocean. - Improving the computing efficiency of the reanalysis system. - Partnership with decadal prediction community. - Feasibility of a global reanalysis at 1/12° with the ORCA12 model

  45. 4. Conclusions & Perspectives

  46. GLORYS2: Conclusions GLORYS2V1 (1992-2009):résultats capacité de production de réanalyse globales à méso-echelle: collaboration unique entre l’opérationnel (MERCATOR, CORIOLIS) et la recherche (LEGI, …) production de la première réanalyse au niveau européen multi-données (SLA, SST, in situ) eddy resolving sur la période altimétrique. résultats de très bonne qualité, GLORYS2V1 > GLORYS2V1.validation extensive dans un cadre international (MyOcean, Godae) reconnaissance au niveau international, >40 utilisateurs, applications très variées.

  47. GLORYS2: Perspectives GLORYS2V2 (1992-2009): reanalysis is close to be finished Improvements: - ERA-Interim corrected precipitation with GPCPv2 observations - Iceberg melt parameterization in the Antarctic region - New MDT + new MDT errors from an objective analysis of 3 MDT products - On line Quality Control on of situ data temperature and salinity profiles - Assimilation of In situ profiles from sea mammals (T, S profiles) in the Antarctic (2004-2009) → Available beginning 2012.

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