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 1.Introduction: - GLORYS project overview - European context 2.GLORYS2 : an eddy permitting (1/4°) global ocean reanalyses of the « altimetric era » - reanalysis system overview - results 3.GLORYS / MyOcean reanalysis meeting (June 2011): outcome 4.Conclusions and perspectives Outline

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 ( ) produced in 2009 : GLORYS1V1 Objectif en 2011: Achever la production de GLORYS2V1 ( ) 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 – Objectives GLORYS is a joint project: MERCATOR-Océan DRAKKAR consortium (France, Germany, UK) CORIOLIS data center & CLS Toulouse Various Research Laboratories in France: LOS, CNRM, LOCEAN Cooperation with EU funded FP7 MyOcean project MOTIVATION: The need for a realistic description of the ocean state and variability over the recent decades, at the global scale, and at the scale of the ocean basins and regional seas. OBJECTIVES: Produce an eddy permitting global ocean/sea-ice reanalysis spanning the “altimetric + ARGO" era Promote the use of reanalysis products in the climate community GLORYS project

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

7 MyOcean project: 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 Global ocean reanalyses at EU level

8 Two reanalyses versions 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. Global ocean reanalyses at EU level MyOcean project: Within WP4:  Global ocean reanalysis production & assessment

9 2. GLORYS2V1: reanalysis system overview

10 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 GLORYS2: reanalysis system overview

11 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 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.

12 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 correction of ERA-Interim radiative fluxes

13 ERAInterim : (monthly running mean) daily mean Climatology Satellite Obs : (monthly running mean) daily mean Climatology Daily Climatology of corrective factor Daily ERAInterim field: large scale x Daily ERAInterim field: small scale Daily Corrected ERAInterim: large scale + Daily Corrected ERAInterim field  The correction is local, (i,j) grid point.  Large scales correction only.  Gewex climatology : ; Indian Gap before.  Gewex [40S-40N] : -3% SW and -6% LW (as Large & Yeager 2004 for ISCCP)  GPCPV2.1 Climatology:  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. Method of correction

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

15 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 anomalies from 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 GLORYS: DATA ASSIMILATION SCHEME

16 “double backward” IAU: Obs Increment repartition ANALYSIS N FCST N+1 FCST N

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

18 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,

19 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

20 2. GLORYS2V1 reanalysis : results

21 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

22 Data assimilation diagnostics for T Global misfit averageGlobal misfit RMS No BIAS RMS is stable Results: GLORYS2V1 reanalysis : ARGO is getting in

23 Data assimilation monitoring : SLA GLORYS2V1 reanalysis results No BIAS RMS ~7cm

24 CLASS1 metric - difference with climatology SST (0.5 m depth): difference with Levitus climatology GLORYS2REFERENCE: MJM95 Results: GLORYS2V1 reanalysis :

25 CLASS1 metric - difference with climatology Temperature (at 100 m depth): difference with Levitus climatology Results: GLORYS2V1 reanalysis : GLORYS2REFERENCE: MJM95

26 CLASS1 metric - difference with climatology Salinity (at 0.5 m depth): difference with Levitus climatology Results: GLORYS2V1 reanalysis : GLORYS2REFERENCE: MJM95

27 CLASS1 metric - difference with climatology Salinity (at 100 m depth): difference with Levitus climatology Results: GLORYS2V1 reanalysis : GLORYS2REFERENCE: MJM95

28 GLORYS2V1 Levitus et al., GRL 2005 Ocean Heat Content 0-700m J Results: GLORYS2V1 reanalysis :

29 Ocean Heat Content 0-700m GLORYS2V1 Lyman et al GLORYS2V1 reanalysis Observations only Results: GLORYS2V1 reanalysis :

30 Ocean Heat Content 0-700m Lyman et al MJM95 reference simulation Observations only Results: GLORYS2V1 reanalysis :

31 Ocean global heat budget Levitus 1998 Climatology GLORYS2V1 [0-2000m] global mean temperature Mean temperature trend = W/m 2 Results: GLORYS2V1 reanalysis :

32 SST trends ___ GLORYS: 0.10°C/decade OBS. : 0.17°C/decade Results: GLORYS2V1 reanalysis :

33 Sea level rise Obs. (Altimetry) Results: GLORYS2V1 reanalysis : Mean sea level rise 2.8 mm/year

34 Arctic Sea Ice: Ice extent SEA ICE EXTENT INTERANNUAL ANOMALIES Correlation = 0.9 Results: GLORYS2V1 reanalysis :

35 Arctic Sea Ice Extent: September 1996 maximum Results: GLORYS2V1 reanalysis :

36 Arctic Sea Ice Concentration CLASS1 metric - difference with climatology

37 Arctic Sea Ice Extent: September 2007 minimum Results: GLORYS2V1 reanalysis :

38 Artic Sea Ice Volume estimation Results: GLORYS2V1 reanalysis :

39 15 m zonal velocity Under estimation of surface velocities Still major flaws in the representation of equatorial undercurrents (the FREE RUN is far better) CLASS1 metric - difference with climatology Results: GLORYS2V1 reanalysis : SVP drifter velocities are biased Grodsky et al. GRL 2011

40 Comparison with Tide Gauges: CLASS2 metric – local comparison with independent data GLORYS2 GLORYS1 Results: GLORYS2V1 reanalysis :

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

42 Maximum AMOC at 26.5 o N AMOC [Sv]1993 – – 2008 UR ± ±1.17 RAPID−18.59±1.31 Results: UR025.3 reanalysis (U-Reading) Courtesy Maria Valdivieso, U-Reading

43 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 Results: GLORYS2V1 reanalysis :

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

45 VALIDATION: Comparison with independent data Tide gauges (GLOSS, SONEL, BODC) GLORYS1-V1 – Validation/results Correlation of time series (3 day means, co-located)

46 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) …

47 3. GLORYS / MyOcean reanalysis meeting in June 2011

48 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 GLORYS/MYOCEAN Workshop en Juin 2011 :

49 - 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 Conclusions from GLORYS/MYOCEAN Workshop:

50 4. Conclusions & Perspectives

51 GLORYS2: Conclusions GLORYS2V1 ( ):résultats 1. capacité de production de réanalyse globales à méso-echelle:  collaboration unique entre l’opérationnel (MERCATOR, CORIOLIS) et la recherche (LEGI, …) 2. production de la première réanalyse au niveau européen multi-données (SLA, SST, in situ) eddy resolving sur la période altimétrique. 3. résultats de très bonne qualité, GLORYS2V1 > GLORYS2V1. validation extensive dans un cadre international (MyOcean, Godae) 4. reconnaissance au niveau international, >40 utilisateurs, applications très variées.

52 GLORYS2: Perspectives GLORYS2V2 ( ): 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 ( ) → Available beginning 2012.