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

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. CabanesLEGI, Mercator Océan, Coriolis

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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

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1. Introduction

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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.

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GLORYS-1

GLORYS-2

Stream1: 2002-2008“ARGO”

Stream2: 1993-2007“altimetry”

T/S prof.: ~1000SST:1°x1° SLA: 2~3 satellites

T/S prof.: 2000~4500SST: 0,5°x0,5° 0,1°x0,1°SLA: 3~4 satellites

Number of Obs. / 7 days

GLORYS: different Streams

1992 2002 NOW

GLORYS1V1: produced and delivered to users early 2009 GLORYS2V1: produced and delivered to users early 2011

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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

Global ocean reanalyses at EU level

http://www.myocean.eu.org/

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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: www.myocean.eu.org

Within WP4: Global ocean reanalysis production & assessment

http://www.myocean.eu.org/

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2. GLORYS2V1: reanalysis system overview

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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

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Model: DRAKKAR ORCA025 configurationNEMO3.0/3.2 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.

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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

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ERAInterim : (monthly running mean) daily mean ClimatologySatellite Obs : (monthly running mean) daily mean Climatology

Daily Climatology of corrective factor

Daily ERAInterim field: large scalex

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 : 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.

Method of correction

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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

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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

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Delayed time observations for data assimilation

• Assimilated data : • Along track DT SLA (SSLATO/DUACS) : Jason-1, Jason-2,

Envisat, GFO, ERS1, ERS2, Topex/Poseidon

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Envisat, GFO, ERS1, ERS2, Topex/Poseidon• Reynolds AVHRR-only 0.25° SST,

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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

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2. GLORYS2V1 reanalysis : results

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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

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Data assimilation diagnostics for T Global misfit average Global misfit RMS

No BIASRMS is stable

Results: GLORYS2V1 reanalysis : 1992-2009

ARGO is getting in

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Data assimilation monitoring : SLA

1992 2009

GLORYS2V1 reanalysis results

No BIAS

RMS ~7cm

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CLASS1 metric - difference with climatology

SST (0.5 m depth): difference with Levitus climatology

GLORYS2 REFERENCE: MJM95


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Temperature (at 100 m depth): difference with Levitus climatology



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Salinity (at 0.5 m depth): difference with Levitus climatology



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Salinity (at 100 m depth): difference with Levitus climatology



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GLORYS2V1

Levitus et al., GRL 2005

Ocean Heat Content 0-700m

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JResults: GLORYS2V1 reanalysis : 1992-2009

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GLORYS2V1

Lyman et al. 2010

GLORYS2V1 reanalysisObservations only

1992 2009


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Lyman et al. 2010

MJM95 reference simulationObservations only

1992 2009


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Ocean global heat budget

1992 2009

Levitus 1998 Climatology

GLORYS2V1

[0-2000m] global mean temperature

Mean temperature trend = + 0.5 W/m2


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SST trends

___ GLORYS: 0.10°C/decade- - - OBS. : 0.17°C/decade


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Sea level riseObs. (Altimetry)


Mean sea level rise 2.8 mm/year

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Arctic Sea Ice:Ice extent

SEA ICE EXTENT INTERANNUAL ANOMALIES

Correlation = 0.9


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Arctic Sea Ice Extent:September 1996 maximum


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Arctic Sea Ice Concentration


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Arctic Sea Ice Extent:September 2007 minimum


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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 climatologyResults: GLORYS2V1 reanalysis : 1992-2009

SVP drifter velocities are biased

Grodsky et al. GRL 2011

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Comparison with Tide Gauges:

CLASS2 metric – local comparison with independent data

GLORYS2

GLORYS1


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GLORYS reanalysisRAPID-MOCHA measurements

= in situ observations (after, Bryden et al., 2005)

Maximum Atlantic MOC at 26.5°NResults: GLORYS2V1 reanalysis : 1992-2009

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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


44innovation T profile

Obs.CLIMFCST

Obs.CLIMFCST

S profileinnovation

Quality Control on in situ data performed in GLORYS reanalysis:

Help to improve delayed time in situ data bases


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GLORYS users

> 40 users, data volume provided > 16 TBseveral 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)• …

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3. GLORYS / MyOcean reanalysis meeting in June 2011

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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 :

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- 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:

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4. Conclusions & Perspectives

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GLORYS2: Conclusions

GLORYS2V1 (1992-2009):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.

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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.

Documents

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