Copernicus Marine Environnement Monitoring Service (CMEMS) regional reanalyses Jonathan Beuvier, Marie Drévillon, Karina von Schuckmann, Gilles Garric, Yann Drillet, Pierre-Yves Le Traon Mercator Océan, Ramonville Saint-Agne, France

19/05/2016 C3S Regional Reanalysis Workshop, Reading 1 OUTLINE

• CMEMS organisation

• CMEMS Multi-Year Products (MYP) • Ocean State Report (OSR), Ocean Monitoring Indices (OMI) • Data reprocessing, a pre-requisite input for reanalyses • Status of regional reanalyses in CMEMS • Requirements for regional reanalyses forcings

• Mercator Océan reanalyses • Atmospheric forcings correction method for global reanalyses • MEDRYS, a Mediterranean Sea regional reanalysis

19/05/2016 C3S Regional Reanalysis Workshop 2 2 CMEMS technical « internal » Framework: building blocks

Cliquez et modifiez le titre

Figure 1: System overview of Copernicus Marine Environment monitoring service chain as presented by the European Commission to the GMES/Copernicus User Forum. From the Technical Annex of the Delegation Agreement between the EU and Mercator Ocean

19/05/2016 C3S Regional Reanalysis Workshop 3 CMEMS Multi-Year Products (MYP): CONTINUITY

AIM: • Maintain MYP time series close to real time  1 year before RT (long term goal: few month before RT)

MOTIVATION: • Guarantee for user delivery state-of-the-art operational MYP products and services • Develop a robust basis for annual ocean state reporting

CHALLENGE: • Operational production of MYP close to RT

19/05/2016 C3S Regional Reanalysis Workshop 4 CMEMS MYP: Ocean monitoring and reporting: 2 fundamental tools CMEMS Ocean State Report (OSR)

CMEMS Ocean Monitoring Indicators (OMIs) Operational time series which allow a regular monitoring of the ocean state, variability and change at global and European scale from 1992 up to RT, together with a quality description and scientific context

19/05/2016 C3S Regional Reanalysis Workshop 5 CMEMS MYP: Ocean monitoring and reporting PRIORITIES for OCEAN MONITORING INDICATORS

1 CMEMS MYP 2 Climate MYP Consistency DM/NRT, but not a Climate quality (consistency and priori optimized for climate homogeneity), but cannot answer applications operational MYP requirements

1 & 2 CMEMS OMI* from MYP Climate quality & state-of-the-art  merge these two philosophies on the long-term

*OMI: Ocean Monitoring Indicator

19/05/2016 C3S Regional Reanalysis Workshop 6 Reprocessing of observations done by CMEMS TACs: a pre-requisite

• In situ T(z), S(z) mainly for data assimilation (but also velocity from drifters, elevations from tide gauges etc…)Cliquez et modifiez • Sea level anomalies from satellite altimetry le titre • SST • Sea ice concentration, drift, thickness • Winds

19/05/2016 C3S Regional Reanalysis Workshop 7 IN SITU reprocessing : main input for 3D ocean data assimilation

___ XBT V1 V2 ___ MBT including EN4 and NATO ___ CTD declassified observations ___ Profilers ___ ondulating CTD and Sea Mammals ___ others

1950 1970 1990 2010

19/05/2016 C3S Regional Reanalysis Workshop 8 Ocean basins in situ sampling rates

Ocean reanalysis in the Southern oceans is still a challenge

19/05/2016 C3S Regional Reanalysis Workshop 9 Altimetry: important input for ocean RAN

Use of all the altimeter missions available from end 1992, up to now: 10 altimeter missions (+2 futures)  ~75 cumulative years of altimeter measurements to process

Cliquez et modifiez le titre

19/05/2016 C3S Regional Reanalysis Workshop 10 CMEMS regional ocean RANs status MFC Model (hor Data Period currently Surface forcing (hor Rivers IC/BC (production resolution) assimilation covered resolution) center) ARC (NERSC) HYCOM V2.2.12 Deterministic 1991-2014 ERA interim (~80km, 6h Monthly clim EnKF / 3h for SW) clim SST, T(z), S(z), Atlimetry, Ice concentration BAL (SMHI) NEMO V3.6 (~3.7 3DEnVAR 1992-2014 EURO4M (~22km, 6h) EHYPE GLO RAN/clim (2017) km) SST, T(z), S(z), ice Cliquez et modifiez charts le titre IBI NEMO V2.3 (~9km) SEEK SAM2V2 + 2002-2014 ERA interim (~80km, 3h) Ifremer + GLO RAN (MO/PdE) 3DVAR bias EHYPE correction SST, T(z), S(z), Atlimetry MED (INGV) NEMO V3.4 OceanVAR 1987-2014 ERA interim (~80km, 6h) Monthly Clim/GLO RT 3DVAR 1955-2014 AMIP (~130km, 12h) clim SST, T(z), S(z), Atlimetry NWS NEMO FOAM AMM7 NEMOVAR 1985-2014 ERA interim (~80km, 3h) EHYPE Clim/GLO RAN (UKMO) V1 (~7 km) 3DVAR (UKMO) and BAL SST IOW GETM

GLO (MO) NEMO V3.1 (~25 km) SEEK + 3DVAR 1992-2014 ERA interim (~80km, 3h) Monthly Clim bias correction clim SST, T(z), S(z), Atlimetry, Ice concentration Good to know

• All have biogeochemistry component, MED MFC is the most advanced in BGC data assimilative RAN Cliquez et modifiez le titre • Ensembles of RAN -> NWS MFC, GLO MFC

19/05/2016 C3S Regional Reanalysis Workshop 12 Status of multi year products MED

CMEMS-MED-MFC V2 reanalysis: model setup and products

Assimilated variables: T, S, SLA SLA_L3_REP_OBS_008_020 [008_19], PHYS BIO MEDATLAS, SEADATANET, Assimilated variable: chla INSITU_OBS_013_035 (Argo-XBT-CTD) OC_L3_REP_OBS_009_073

Forcing and boundaries: - ECMWF ERAinterim/AMIP Forcing and boundaries - Climatological river runoff Data assimilation Data assimilation - ERAInterim - Climatological river precipitation/CMAP OCEANVAR 3DVAR discharges precipitation - Atlantic BCs from - Atlantic BCs from PSY3 MEDATLAS global model - Atm forcing from NEMO3.4 OGSTM-BFM4.0 literature Satellite SST (surface flux nudging): GOS-CNR-SST-HR-RAN/DT- MEDITERRANEAN – SST_MED_SST_L4_NRT_OBSERVATI ONS_010_004_a/HadSST1 CMEMS products

5 0 0 0 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 8 8 8 9 9 9 9 9 9 9 9 9 9 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 REAN-PHYS-006-004 REAN-PHYS-006-009 REAN-BIO-006-008 Multi Model Ensemble – Multi Year Product Courtesy of I. Golbeck BSH

MME MYP – single MYPs spatial coverage

IBIRYSV1: will provide a larger domain

We need at least 3 MYP in the same area. MME - MYP

• SST mean standard deviation for 2011 General requirements for atmospheric forcing for regional oceanic RAN

Spatial resolution Also true for future GLO 1/12° RAN! ~20 km Time resolution hourly if possible Parameter list: Cliquez et modifiez most make use of CORE BULK: if flux formulation used: le titre

2-m air temp total, solar and non-solar heat flux (accumulated) 2-m specific humidity SST used to compute the heat fluxes 10-m wind components (u and V) wind stress components (tauU and tauV) air pressure at sea level air pressure at sea level total cloudiness water flux components (evaporation, precipitation, snow) downward shortwave radiation (accumulated) downward longwave radiation (accumulated) need of fluxes as balanced as possible (especially for semi- total precipitation (accumulated) enclosed basins) snow precipitation (accumulated) Provide uncertainty estimates -> sensitivity studies, ensembles For winds: can be estimated with CMEMS OSI TAC Double penalty effects with high resolution? Ensemble atsmopheric reanalyses to build ensemble oceanic reanalyses and multi-model ensembles

River runoff data: need of long-term datasets to be used instead of climatologies

19/05/2016 C3S Regional Reanalysis Workshop 16 Forcings corrections: background

Downward SW Flux 2002 SST (2002) ERAinterim - GEWEX model – RTG

SST spatial errors structures

Rainfalls ERAInterim – PMWC SSS (2002-2006) model – Levitus98 climatology

SSS spatial errors structures

Devpt method to correct SW, LW & Precipitations Large Scale ERA-Interim Fluxes with GEWEX SRB and PMWC

19/05/2016 C3S Regional Reanalysis Workshop 17 Method of forcings correction

ERAI : monthly mean Climatology Climatology of x Daily ERAI field: Satellite: monthly corrective factor large scale mean Climatology

Daily Corrected ERAI Daily ERAI: small large scale + scale

Daily Corrected ERAI field

. The correction is local (i,j). • No change of interannual signal. . Large scales correction only. • No change of synoptic patterns . Gewex SRB climatology (1999-2007) for SW & LW fluxes. (cyclones). . PMWC Climatology (1992-2006) for rainfalls fluxes. • The method can be applied outside . No correction at high latitudes (> 65N and < 60S) the satellite period. . No correction for climatology < 1W.m-2 or <50mm/yr (hyper arid climate).

19/05/2016 C3S Regional Reanalysis Workshop 18 The example of the MEDRYS reanalysis

More « climate-oriented » regional reanalysis : • use of dedicated tools (numerical model, forcings, data assimilation system settings) for the Mediterranean Sea • to have the more consistent and the more interannual as possible lateral forcings (Atlantic boundary conditions, atmospheric forcings, river runoffs) with the same characteristics all along the simulated period • configurations closed to Regional Climate System Models (RCSM)

• Work done in the frame of the MISTRALS (Mediterranean Integrated STudies at Regional And Local Scales) and Med- CORDEX (Mediterranean contribution to the Coordinated Regional Climate Downscaling Experiment) international programs.

19/05/2016 C3S Regional Reanalysis Workshop 19 Regional oceanic configuration: NEMO-MED12 model

• NEMO v3.1 code (Mercator oper version at Météo-France HPC) • Horizontal grid from ORCA12 at 6-8 km < Rossby deformation -6 radius ~10-15 km (eq. to a 1/14°-1/18° regular grid) • Z vertical grid with 75 levels (1m to 135m thickness) • New high resolution bathymetry -11 -7.5 (MERCATOR-LEGOS v10 product at 1/120° resolution) Bathymetry (m) Atlantic buffer zone : • Closed boundary at 11°W Newtonian dampings to ORAS4 monthly anomalies with following time scales τ :  and S (3D) : τ between 2 days -> 90 days SSH : τ between 1.7 second -> 90 days

19/05/2016 C3S Regional Reanalysis Workshop 20 Atmospheric forcings, initial and boundary conditions

• Free simulation starting in October 1979 from Medatlas-1979 (Rixen et al., 2005) in the Mediterranean side and from WOA05 (Levitus et al., 2005) in the Atlantic side. The reanalysis starts from the state of the free run on the 30th September 1992 (beginning of the altimetry era). • 12-km and 3h-atmospheric fluxes from ALDERA (CNRM), dynamical downscaling of the ERA-Interim reanalysis with ALADIN-Climate (Herrmann et al. 2011).

SST retroaction for the free run (Barnier et al. 1995), coefficient of -40 W/m²/K (CLIPPER Project 1999). The total heat flux of the free run is used for the reanalysis (including the retroaction term). Topography of ALADIN-Climate

No SSS damping, 2D water flux correction in the water flux.

33 main rivers + Black Sea (interannual datasets from Ludwig et al., 2009 and Stanev & Peneva, 2002): freshwater added as precipitation at mouth points + coastal runoff (residual land-surface freshwater budget).

19/05/2016 C3S Regional Reanalysis Workshop 21 Regional oceanic reanalyses MEDRYS1

MEDRYS1V1 MEDRYS1V2

Observations: Ocean model: In-situ (Coriolis CORA4.0/CORA4.1 database) and satellite NEMOMED12v75 model, ALDERA forcing data (SST AVHRR-AMSR and SLA from SALTO/DUACS)

Data assimilation scheme (Lellouche et al., 2013) One analysis per several days (7-day/5day cycle) Control Space SEEK + no shock thanks to Analysis repartition of the anaylsis SSH + SSHbias correction over the week Modal Space T(k) + T (k) (Reduced Space) bias 3DVAR correction at large space- and time-scale  S(k) + Sbias(k) 3D modes U(k) acting on multivariate multidata 3D space SEEK filter algorithm V(k) 19/05/2016 C3S Regional Reanalysis Workshop 22 Experimental design for MEDRYS1 reanalyses

MEDRYS1V2

19/05/2016 C3S Regional Reanalysis Workshop 23 Added value of the high-resolution in ALDERA

Wind and heat flux on the 14th March 2013 Wind direction and speed on the 16th September 2012

ALADIN-150km

ALADIN-50km

ALADIN-12km (ALDERA)

24 Need of fluxes giving balanced budgets (from Hamon et al. 2016)

Heat flux components

Water flux components

25 Thank you for your attention! Any questions?

19/05/2016 C3S Regional Reanalysis Workshop, Reading 26 Statistics on assimilated data: SLA

-0.8cm -0.7cm

MEDRYS1V1 MEDRYS1V2

6.5cm 5.0cm

27 Statistics on assimilated data: SST

-0.060°C -0.026°C

MEDRYS1V1 MEDRYS1V2

0.74°C 0.57°C

28 Statistics on assimilated data: in-situ Temperature 0

-200

-500

-1000

-2000 1993 2013 1993 2013 MEDRYS1V1 MEDRYS1V2 Salinity0

-200

-500

-1000

-2000 1993 2013 1993 2013

29 Monthly heat and salt contents (courtesy G. Jorda for the IMEDEA construction)

T3D[0-150m] S3D[0-150m]

T3D[150-600m] S3D[150-600m]

T3D[600m-bottom] S3D[600m-bottom]

10/02/2016 30