1. © Crown copyright Met Office IGST XIII UK national report Matt Martin Silver Spring, USA, 2 - 4 June 2008

2. © Crown copyright Met Office Contents Update on NCOF Progress with NEMO ocean model framework Data assimilation progress and plans Ecosystems OSTIA Shelf-seas Data delivery

3. © Crown copyright Met Office Update on NCOF NCOF was launched in March 2005 Partners are the Met Office and the NERC marine research institutes POL, NOCS, ESSC, PML CEFAS are Observers, with a view to joining The Consortium Agreement is nearing completion The scope of NCOF is being broadened to include a wider range of timescales and to more explicitly include observational programmes. NCOF Workshops Annual gatherings NCOF website: http://www.ncof.co.uk

4. © Crown copyright Met Office Progress with NEMO Overview NEMO is the Nucleus for European Modelling of the Ocean All Met Office ocean modelling activities will use NEMO, including shelf-seas, FOAM, seasonal forecasting and climate prediction. NEMO Consortium Agreement has been signed NEMO Systems Team Core of team at CNRS (Paris), but consortium agreement commits resources from NOCS (Southampton) and Met Office (Exeter) NEMO Users Includes the open ocean, shelf seas, seasonal forecasting and climate prediction communities Intention to use NEMO as the primary open ocean modelling tool across all communities

5. © Crown copyright Met Office FOAM model component is being transitioned to use NEMO. For the My Ocean project, responsibility for global and North Atlantic coverage is led by Mercator with FOAM providing backup. Model configurations are shared with different choices for surface forcing, parameter settings and assimilation. Currently using LIM2 ice model. Plan to switch to CICE. The initial system has been run in hindcast mode and is being run in the trial operational suite. First ORCA025 hindcast run from 1 st April 2005 – April 2007: Initial conditions produced by running model only for 3 months (starting from operational FOAM 1˚ restart file on 1 st Oct 2004) then with assimilation for 3 months. Forced by 6-hourly Met Office NWP surface fluxes. With LIM2 ice model. Progress with NEMO: FOAM

6. © Crown copyright Met Office Global ¼˚ (ORCA025) grid, bathymetry and river outflow climatology provided by Mercator N. Atlantic 1/12˚ Indian Ocean 1/12˚ Med. 1/12˚ All configurations have 50 levels with 1m resolution near surface. Progress with NEMO: FOAM configurations

7. © Crown copyright Met Office Initial results of verification of hindcast of ¼˚ NEMO. Comparison of model background with observations (before they’ve been assimilated). Averaged errors for Jan 2006 (after 10 months). TemperatureSalinity Temperature overall RMS error 0.77K

8. © Crown copyright Met Office Progress with NEMO: Comparison of trial operational NEMO with OSTIA SST FOAM-NEMO SST on 14 th May 2008OSTIA SST analysis on 14 th May 2008

9. © Crown copyright Met Office The existing operational FOAM system and the new global FOAM-NEMO system will be used as part of the GODAE intercomparison project. The new FOAM-NEMO system will be used to run data withholding experiments for the GODAE OSE project. Future plans are to fully implement the global and regional FOAM-NEMO configurations operationally in 2008. These will take over from the existing FOAM system at that stage. A number of hindcasts with the models will be run and assessed. Future model developments will aim to improve the results of the hindcasts. Transition the system to the new supercomputer in 2009. Progress with NEMO: FOAM model plans

10. © Crown copyright Met Office 19601970198019902000 year Drake passage transport (Sv) Drake Passage transport High resolution hindcasts (with ecosytem models included) eg global 1/4 degree NEMO model has now completed 1958-2001, then started again from the 2001 state but with fluxes from 1958 to allow the ocean to properly spin-up Proposal to compare NOCS hindcast runs (without data assimilation) with similar runs undertaken by ESSC which do include assimilation - to assess the effect of the assimilation. Progress with NEMO: Recent work at NOCS

11. © Crown copyright Met Office Global Ocean Modelling with Adaptive Unstructured Grid Methods Aim: produce a global circulation model which fully utilises three-dimensional adaptive mesh technology – based on ICOM (FInite-eLement Adaptive grid Modelling of Ecosystems and Nutrient Transport) Aim: Embed an ecosystem model into a newly developed, non-hydrostatic, finite element, adaptive grid, physical ocean model Progress with NEMO: Long-term modelling plans at NOCS

12. © Crown copyright Met Office ESSC: Model/Synthesis details Completed Synthesis experiments (Hydrography only assimilation) Global 1° resolution (1958-2004) 46 years Global 1/4° resolution (1987-2004) 18 years NEMO modelling framework Collaboration with DRAKKAR consortium who have run the global 1/4° resolution model only for 46 years. Bulk forcing (DFS3) from ERA40/ECMWF operational analyses & CORE (ISCCP) Data assimilation scheme is based on an isothermal analysis (changes depth of isotherms and salinity on isotherms). Now extending runs 2005-2007 using ECMWF Operational forcing 1989-1998-present will be done using ERA-Interim (4DVar atmosphere with better fluxes)

13. © Crown copyright Met Office ESSC: Biases in the 2004 mean state ORCA025-G70 Simulation only ORCA025-R07 Assimilation Climatology WOA05 Average 300-1000m

14. © Crown copyright Met Office Transports (Black Simul., Green Synth.)

15. © Crown copyright Met Office All FOAM configurations assimilate a range of data using an Optimal Interpolation type method. Data types include: Temperature and salinity profiles including Argo floats (also XBTs, CDTs, buoys,…) Satellite altimeter Sea Surface Height In situ and satellite Sea Surface Temperature Sea-ice concentration Argo float distribution Satellite SST data: 50km product (from NESDIS) Argo Network as of April 2008 Altimeter SSH data for 10 days Processed for 1/9º North Atlantic model Data assimilation: Overview of FOAM scheme

16. © Crown copyright Met Office Overall data assimilation methodology the same as current operational FOAM. Includes assimilation of T and S profile data, satellite altimeter SLA data, in situ and satellite SST data, and sea-ice concentration data. Improvements include: First-guess-at-appropriate-time (FGAT) which provides more accurate calculation of the model counterpart of the observation. Improved sea ice assimilation uses OSI-SAF sea ice concentration data and uses the OI scheme as do all the other data types. Data assimilation in FOAM: Implementation in NEMO Observed sea-ice concentration 1 st Feb 2006 Background sea-ice concentration 1 st Feb 2006

17. © Crown copyright Met Office To be included in next operational change and next hindcast run: New error covariances being generated for ORCA025 using two techniques – using (o-b) and NMC method - using data from the 2 year hindcast. Altimeter bias correction in order to account for inconsistencies between the mean dynamic topography (MDT) and the model. Pressure correction, to account for model biases in the tropics. Scheme to include correlation scales which vary depending on the horizontal gradients of potential vorticity in the background field. Assimilation of GHRSST data (high-resolution SST), including satellite SST bias correction, as is used in OSTIA. Data assimilation in FOAM: Recent developments in FOAM-NEMO

18. © Crown copyright Met Office STD BIAS No bias correction (black) compared to bias correction (red) After only 1 month SSH RMS error 10 cm rather than 12 cm Minor improvements in T and S RMS mean Data assimilation in FOAM: Altimeter bias correction scheme

19. © Crown copyright Met Office Assimilate various high resolution SST data sets from GHRSST (L2p data) Include bias correction scheme used by OSTIA AATSR and in situ data treated as reference data set in bias correction 1 day of satellite data – 8 th April 2008 Data assimilation in FOAM: Assimilation of GHRSST data

20. © Crown copyright Met Office A review of the various assimilation schemes available for use in operational ocean forecasting has been carried out. It was decided to begin implementing a variational scheme, NEMOVAR. Developed at CERFACS and ECMWF. Initial implementation in FOAM will be 3DVar with the capability to move to 4DVar in the future. Developments will be made to implement anisotropic error covariance representation within NEMOVAR. Investigate impact of a different change of variable to, for instance, density and spiciness. Data assimilation in FOAM: Plans

21. © Crown copyright Met Office Ecosystem modelling FOAM-HadOCC overview FOAM-HadOCC running at 1º, 1/3º and 1/9º resolution Assessment of initial year-long integrations underway Ocean colour data assimilation scheme (developed by NOCS) implemented and testing started Schematic of HadOCC Development of open ocean water clarity capability Hadley Centre Ocean Carbon Cycle model (HadOCC) has been coupled with the FOAM system NPZD ecosystem model

22. © Crown copyright Met Office  Daily mean RMS errors in the North Atlantic  Air-sea exchange of CO 2 significantly improved after assimilating ocean colour data Detritus (mmol N/m 3 )Nutrients (mmol N/m 3 ) Ecosystem modelling: Identical twin experiments Control - truth Assimilation - truth

23. © Crown copyright Met Office  Global average RMS (solid lines) and mean (dashed lines) errors compared to satellite chlorophyll data. Green: no DA Black: only physical DA Red: physical and biological DA  The scheme appears to be effective at correcting chlorophyll  Validation of other biological variables against independent data (CAVASOO) has begun Ecosystem modelling: Real world experiments

24. © Crown copyright Met Office Ecosystem modelling: Plans The key next steps are: further quantitative validation of initial FOAM-HadOCC integrations. further refinement of biological assimilation scheme. parameter tuning (required to improve performance). 10-year re-analysis of FOAM-HadOCC with ocean colour and physical assimilation (1º global). on-line coupling to NEMO.

25. © Crown copyright Met Office NanoPhyto Si Diatoms FeN MesoZoo MicroZoo Slow detritus Fast particle flux Model of Ecosystem Dynamics, nutrient Utilisation and SequestrAtion Chlorophyll (mg m -3 ), 15 May MEDUSA in ¼º NEMO

26. © Crown copyright Met Office Shelf seas forecasting at the Met Office 6km MRCS Model 1nm Irish Sea Model 12km Atlantic Margin Model NEMO will form basis for our North-west Shelf system. Boundary conditions will come from the 1/12 degree N Atlantic FOAM-NEMO model. Various new schemes implemented in NEMO by different European groups to enable running in the shelf-seas POLCOMS and NEMO run on AMM domain, same horizontal + vertical resolution. 1-year tides-only experiments forcing with 15 tidal components at lateral boundaries. Validated against tide gauge and buoy data, plus Topex data. Each model run with native TKE scheme and also with k-ε model (Canuto et al 2001) within GOTM framework.

27. © Crown copyright Met Office Validation against satellite data (TPXO): amplitude errors (m) POLCOMSNEMO

28. © Crown copyright Met Office OSTIA: Operational SST & Sea Ice Analysis Daily 1/20° (~5.6km) global SST analysis. Analysis of the ‘foundation’ SST [pre-dawn or below the diurnal warm layer]. Blend of data sources, using satellite (microwave & IR) and in situ data. Using many GHRSST data products. Almost all Medspiration products. Now running daily, operationally. Using a scheme based on the FOAM assimilation scheme, with persistence based background. Uses sea ice analysis performed by EUMETSAT OSI-SAF (met.no / DMI). Sample analysis for 19 Apr 2007

29. © Crown copyright Met Office OSTIA improved the RMS and bias in the NWP forecasts during the trial period (August 2007). RMS Error Mean Error Reduced Bias at low levels Pressure Level

30. © Crown copyright Met Office Direct links to UK Royal Navy forecasters. For commercial use, data is available from the Met Office’s Data and Products Distribution System (DPDS) at http://www.metoffice.gov.uk/research/ncof/foam/dpds.html Data available for research use from Live Access Server at http://www.nerc-essc.ac.uk/godiva/ A new prototype data server has been developed and is undergoing testing. One new advance with this server is the ability to visualise NCOF data using Google Earth. (http://behemoth.nerc- essc.ac.uk/ncWMS/godiva2.html) Products distribution: Overview

31. © Crown copyright Met Office

32. A service desk will be operated at the Met Office for all European Marine Core Services: Data policy still to be defined but is likely to be freely available to all users and free of charge Users will be able to access data via the service desk using service level agreements (SLAs) Data will be supplied from production centres in Europe Present plan is for data to be available via sftp OpenDAP technologies will be introduced at a later date On-line catalogues will be available to search for products Products distribution: Future system in My Ocean

33. © Crown copyright Met Office Phase errors for M2 component (degrees) POLCOMS-GOTM NEMO-GOTM

34. © Crown copyright Met Office Observation Operator (also in NEMOVar) allows Isotherm / Isopycnal depths Salinity / Spiceness on Isotherm / Isopycnal surfaces For isotherms: Given T, S -> Calculate Z(T), S(T) for model and observations Za(T) = Zb(T) + ΔZ(T) or Ta(z) = Tb(z) + ΔT(z) Sbal(z), such that Sa(Ta)=Sb(Ta) Sa(T) = Sb(T) + ΔS(T)‏ For isopycnals: Given T, S -> Calculate Z(ρ), π(ρ) for model and observations Z’(ρ) = Zb(ρ) + ΔZ(ρ) π’(ρ) = π b(ρ) + Δπ(ρ) Current Syntheses all use Isotherm analyses ESSC: Isothermal/Isopycnal Assimilation

35. © Crown copyright Met Office RMS Salinity Misfits : 1988-2004 ORCA1-R70 ORCA1-R07-RA_t1 ORCA025-R07-RA_t1 FULL – Global STNA – Sub-trop. N. Atl. 20N-45N, 80W-8W SPNA – Subpolar N. Atl. 45N-65N, 65W-5E MDNA – Mid N. Atl. 30N-45N, 35W-20W