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TOPAZ report

TOPAZ report. L. Bertino, F. Counillon, P. Sakov, E. Simon, G. Zangana, MQ. Fang Mohn-Sverdrup Center/NERSC. GODAE Ocean View ST, Toulouse, June 2009. TOPAZ System overview. System description Validation / metrics Plans. Satellite Data SLA, SST, Ice, In Situ Data. Atmospheric Data.

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TOPAZ report

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  1. TOPAZ report L. Bertino, F. Counillon, P. Sakov, E. Simon, G. Zangana, MQ. Fang Mohn-Sverdrup Center/NERSC GODAE Ocean View ST, Toulouse, June 2009

  2. TOPAZ System overview System description Validation / metrics Plans

  3. Satellite Data SLA, SST, Ice, In Situ Data Atmospheric Data Sea-Ice model Atlantic and Arctic model EnKF Data assimilation system Gulf of Mexico model Eco- system model Uncertainty estimates Ocean Primary production Hindcast studies User-targeted ocean forecasting Analyze the ocean circulation, sea-ice and biogeochemistry. Provide real-time forecasts to the general public and industrial users

  4. The TOPAZ model system • TOPAZ3: Atlantic and Arctic • HYCOM + EVP sea-ice model • 11- 16 km horizontal resolution • 22 hybrid layers • EnKF • 100 members • Observations • Sea Level Anomalies (CLS) • Sea Surface Temperatures (NOAA) • Sea Ice Concentr. (AMSR, NSIDC) • Sea ice drift (CERSAT) 4D-EnKF • Argo T/S profiles (Coriolis) • Runs weekly, 10 days forecasts • ECMWF forcing

  5. EnKF Correlations, SST 3rd Jan 2006 8th Nov 2006

  6. Impact on temperature Impact on salinity Ice concentration multivariate updatesummer [ K.A. Lisæter et al. 2003]

  7. The HYCOM model • 3D numerical ocean model • Hybrid Coordinate Ocean model, HYCOM (U. Miami) • Hybrid coordinate • Isopycnal in the interior • Z-coordinate at the surface • Coupled • Sea-ice model (EVP) • Ecosystem models • NORWECOM (IMR, UiB) • Interface to EnKF • Analysis in model space • u,v, t, s, dp (layer thickness) • Connection to N-MICOM in the Bergen Climate Model

  8. Nesting • Arbitrary resolution and orientation of the nested grids • 6-hours frequency of nesting conditions • Inclusion of tides • Only one-way nesting • A few regions (none in real-time at present) • Gulf of Mexico (with DA, no tides) • Barents Sea (tides, no DA) • Norwegian Sea (tides, no DA) • Fram Strait (tides, no DA)

  9. Application: Iceberg forecasting • Iceberg modelling • PhD of I. Keghouche • Iceberg model forced by a 5 km Barents Sea HYCOM model • Nested into the TOPAZ system • Not yet in real-time • Ensemble of icebergs: • Variable size, Ca, Co Keghouche et al., JAOT, In press

  10. Example of productsicebergs simulations • Random simulations using calving rates for major glaciers, 1 year I. Keghouche

  11. Data service / Transition to operations / computers • NERSC / met.no • March 2008: TOPAZ3 exploited in met.no’s operational suite. • Developments at NERSC, still run as a backup • Data service also duplicated • Updated on Thursd. / Friday • Best guess = ensemble mean • Forecast = 1 member • NERSC: topaz@nersc.no • http://topaz.nersc.no/thredds • Met.no: myocean@met.no • http://thredds.met.no (MERSEA…) • Computing resources • Ensemble forecast 2000 CPU h / week • Analysis • 24 CPU h / week • Met.: IBM (1000 CPUs) • NERSC: Cray XT4 (5500 CPUs) • Products on FTP • BC to ourselves (Fram Strait, Barents Sea) • BC to DMI (Nares Straits) • Surface currents to ECMWF’s wave model.

  12. TOPAZ surface currents in ECMWF wave model Hs: Small improvement of scatter index Larger improvement for peak periods But biases are slightly more negative ECMWF has requested access to TOPAZ data for operations Wave modelling at ECMWF (J. Bidlot, ECMWF) • TOPAZ • control

  13. TOPAZ System overview System description Validation / metrics Plans

  14. Issues with ensemble systems Forecast Analysis Member1 • What is the “best guess”? • Ensemble mean • Minimum least square error • Most suitable for “Accuracy” metrics • But not “Consistency”: • Smoothes the EKE, MLD… • Ensemble SD are computed but not served so far • Doubles the NetCDF file storage • What is the forecast? • So far in TOPAZ = 1 member (for simplicity) • Natural to initialize an ensemble forecast Member2 …… 2 1 Member99 Member100 3 Observations

  15. Arctic Metrics Documentation in MERSEA WP05 report by Bertino, Lisæter, Garric (2005)

  16. Validation of MLD against clim. TOPAZ3 Climatology Too deep mixed layer in the Sub-Arctic Gyre

  17. Bear Island opening, Temperature TOPAZ2 TOPAZ3 IMR obs Apr 2007 Jun 2007 Aug 2007

  18. Online comparison to Argo profiles

  19. Water Transports Denmark Strait Fram Strait Barents Sea opening

  20. Sea ice Transports, 2007 Fram Strait Spitzbergen - Franz Joseph Land

  21. Sea-ice edgeAssimilation + 6 days • Ice concentration from model in color, SSMI 15% ice contour in black. Ice drift is overlaid. • Good overall correspondence between model and data • Visual comparison allows identification of problematic regions • South of Svalbard (Bear Island) model ice edge too far to the north • East Greenland, too little ice South of Denmark Straits • Issues related to model physics • Ice-ocean momentum exchange • Ice models neglect physics which may be important on small scales • Fast ice • MIZ

  22. Ice Forecast skills by region – 6 months averagesee http://topaz.nersc.no Barents Sea N. Alaska Bering Strait Central Arctic Greenland Sea Kara Sea

  23. SSH residuals by region

  24. MERSEA Arctic sections updated • Blue: MERSEA Class2 sections • Red: Sections from IMR • Problem: need to reprocess all past products. • Should the metrics upgrades be synchronized to system upgrades?

  25. TOPAZ System overview System description Validation / Metrics Plans

  26. TOPAZ4HYCOM upgrade (v2.2.12) • Features used for TOPAZ4 • Hybrid grid generator: • 3 different vertical interpolation methods (PCM, PLM, PPM,WENO) • Improved treatment of rivers • Mass fluxes • More stable in shallow waters (Morel et al. 2008)

  27. Other upgrades in TOPAZ4 TESTED ONGOING Forcing fields: ERA-Interim (to be tested) Assimilation of ocean colour in HYCOM-NORWECOM MIZ sea-ice rheology (TOTAL) PLANNED Ferrybox data (Svalbard) Gliders (FFI-met.no) Rio05 MDT HR SST (Ostia/Odyssea) New satellites GOCE, SMOS, CryoSAT • Vertical resolution • 28 layers instead of 22 • Thicker z-levels for deep mixed layers • Sea ice model (EVP) • Advection scheme (WENO) • Snow distribution • Tuning of P* (ice strength) • River fluxes from hydrologic model (TRIP), Oki and Sud (1998) • Bering Strait fluxes from Pacific • Flux: 0.8 Sv at climatology T/S • Sea-level altimeters tracks

  28. Vertical resolutionmaximum z-levels Thin z-levels Thick z-levels

  29. Snow module • Two effects: • Snow increases the albedo • Isolates the ice • Probabilistic snow distribution: Leads to more ice Pacific ice not in TOPAZ V. Vionnet Ice area Ice volume

  30. River forcing - TRIP

  31. Effect of the HYCOM upgradeWeekly SST in Dec. 1999, free run AVHRR L4 SST TOPAZ3 TOPAZ4

  32. Effect of the HYCOM upgradeWeekly SSS in Dec. 1999, free run Next target: N-MICOM (BCM) Incremental remapping TOPAZ3 TOPAZ4

  33. TOPAZ4-TOPAZ3 Transport estimates Improvement of the “critically important fluxes”

  34. Forecast plans • Met.no has switched TOPAZ3 to daily forecasts • Updated fluxes • But not yet daily updates… • Arctic Intercomparison led by NERSC • Involve met.no, NIERSC (ocean, sea-ice) • TOPAZ4 in real-time by Oct. 2010. • Run 10-members 10-days forecasts • Out of the 100 members EnKF ensemble

  35. Reanalysis plan • MyOcean: • 20 years reanalysis with TOPAZ4 • HYCOM 2.2, same horizontal resolution, 28 hybrid layers • Assimilate delayed mode data (hydrographic, ice) • Along-track altimeter data • Schedule • Starting with 2002-2009 • Then years 1989-2002 • Delivery by Oct. 2010

  36. Assimilation of Ocean Color in HYCOM-NORWECOM • Data: • Satellite Ocean Color (SeaWIFS) • Coupled Model: • HYCOM-NORWECOM • (7 compartments) • Problems: • Coupled 3-dimensional • physical-biological model. • High-dimension. • Non-Gaussian variables. • Perspectives: • Environment monitoring. • Fisheries. • Methodological developments

  37. Gaussian anamorphosis with the EnKF Anamorphosis: transformation of the distributions to Gaussian (Bertino et al. 2003) Twin experiments (surface chlorophyll-a synthetic observations) Surface CHLa RMS error EnKF Cut-off of neg. values Gaussian Anamorphosis EnKF Simon & Bertino (OSD, 2009)

  38. Outreach (1) • Dynamics visualization • OPeNDAP client DAPPER/DCHART • http://topaz.nersc.no/ • Inclusion into the Norwegian weather website http://yr.no • University of Bergen: • Operational Oceanography courses • Hands on experience to OPeNDAP in Matlab • Arctic ROOS • Secretariat = S. Sandven (NERSC) • http://www.arctic-roos.org • Has several members • Presents obs and model • IPY – DAMOCLES • Acoustic tomography in the Fram Strait • Monitor heat fluxes in / out of the Arctic

  39. Data service: OPEnDAP/THREDDS Web client: DCHART/DAPPER G. Zangana

  40. Acoustic TomographyDAMOCLES project • Fram Strait, 25th July 2007 • Average sound speed between source and receiver • Uncertainty taken from the TOPAZ ensemble forecast • 100 members • Sept. 2008, deployment successful • More validation to come... [ H. Sagen, NERSC ]

  41. Outreach (2) • China • Nansen-Zhu Center at IAP in Beijing • Jiang Zhu’s group • Shared HYCOM, EnKF/EnOI • Collaboration with NMEFC (operational) • DRAGONNESS project (EU, support action) • India • Nansen Center in Kochi • Shared HYCOM • Collaboration with INCOIS, Hyderabad (operational) • Shared HYCOM, EnOI • South Africa • PhD B. Backeberg, Uni. Cape Town • Shared HYCOM

  42. Work has been done: Nested model around China Seas AVHRR, 27031997 0.25º×0.25º HYCOM, 27031997, 0.1º×0.1º M.Q. Fang (Uni. Qingdao) Comparison between the AVHRR OI sst (from NOAA) and the HYCOM sst

  43. Near Future Research Plan: HYCOM, 27031997, 0.1º×0.1º Further Nesting to some local areas for specific studies, with data assimilation/validation HYCOM, SST 01071998, 1/18º-1/32º

  44. Publicationsmostly MERSEA Oc. Sci. Special issue • Samuelsen A., L. Bertino, and C. Hansen The 2007 North Atlantic spring bloom in operational analysis from the TOPAZ system Ocean Sci. Discuss., 6, 343-369, 2009 • Backeberg B. C., L. Bertino, and J. A. Johannessen Evaluating two numerical advection schemes in HYCOM for eddy-resolving modelling of the Agulhas Current Ocean Sci. Discuss., 6, 429-475, 2009 • Simon E. and L. Bertino Application of the Gaussian anamorphosis to assimilation in a 3-D coupled physical-ecosystem model of the North Atlantic with the EnKF: a twin experiment Ocean Sci. Discuss., 6, 617-652, 2009 • Counillon F., P. Sakov, and L. Bertino Application of a hybrid EnKF-OI to ocean forecasting Ocean Sci. Discuss., 6, 653-688, 2009 • Keghouche, I., L. Bertino, K.A. Lisæter (2009) Parameterization of an iceberg model in the Barents Sea. JAOT, in press.

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