The Mercator-Océan ¼° global ocean forecasting system

1. The Mercator-Océan ¼° global ocean forecasting system Marie Drévillon, Nicolas Ferry, Elisabeth Rémy, Eric Greiner, Jean-Michel Lellouche, Laurence Crosnier, Nathalie Verbrugge, Stéphanie Guinehut, Yann Drillet and the MERCATOR team

2. The Mercator-Océan forecasting systems satellite altimetry + Reynolds SST + in situ data satellite altimetry Oceanic initial conditions for seasonal forecasts Reanalysis 1992-2002 OPA 8.2 free surface 46 vertical levels SLA ENVISAT + JASON + GFO assimilated with OI ECMWF fluxes at the surface Restoring to daily RTG-SST Started from Levitus in January 2005 satellite altimetry + Reynolds SST + in situ data

3. A basis for global climate monitoring Global system heat content in 2005 (0-700m), in 1011 J/m2 Climate change indicators Average depth of the 26°C isotherm in the global forecasting system in September 2005 hurricane indicators

4. Validation with independent in situ dataTAO/TRITON moorings in the Tropical Pacific Ocean 140°W O°N 110°W 5°S Temperature of the global system Temperature of the global system Temperature observed by the TAO buoy Temperature observed by the TAO buoy °C http://www.pmel.noaa.gov/tao/jsdisplay/

5. Validation with independent in situ datatemperatures differences with the CORIOLIS database in January 2006 in the North Pacific 200 to 700 m 0 to 50m 50 to 200m Under 2000 m 700 to 2000 m

6. Validation with independent in situ datasalinity differences with the CORIOLIS database in January 2006 in the North Pacific 0 to 50 m Under 2000 m 200 to 700 m 50 to 200 m 700 to 2000m

7. Validation with observed products The summer Indian Ocean monsoon currents in July/August 2005 0,6 m/s 0,6 m/s 0,3 m/s 0,3 m/s Seen by SURCOUF surface currents deduced from satellite observations Seen by the global system Climatology deduced from ship drift and drifters Schott and McCreary (2001)

8. Validation with observed products The winter Indian Ocean monsoon currents in January/February 2006 Seen by SURCOUF surface currents deduced from satellite observations Seen by the global system 0,6 m/s 0,3 m/s 0,3 m/s 0,6 m/s Climatology deduced from ship drift and drifters Schott and McCreary (2001)

9. Validation with observed productsTemperature and salinity sections at 162°Win the Pacific Ocean in January 2006 Global system °C psu ARMOR3D OA of obs. Clim Levitus January

10. Validation summary • Time evolution of the system validated with independent in situ data • Identification of biases in temperature and salinity: • Differences with in situ data • Comparison with 3D T S observed products • Surface currents validated with clim. and observed surface currents

11. Prospects: Online Systematic Diagnostics MERSEA/GODAE GLOBAL METRICS MOORINGS XBT lines SECTIONS and TRANSPORT WOCE CLIVAR CANADIAN SECTIONS SOOP GLOSS TAO PIRATA MFS MODEL T XBT Observed T MODEL/WOCE-CLIVAR SECTION VOLUME TRANSPORT across FLORIDA Strait : MODEL/CABLE Comparison MODEL/OBS comparison Model/Tide gauge SLA time series comparison

12. Aiming at the 1/12° global systemZoom North Atlantic 1/15°, assimilating altimetry, Reynolds SST andin situ data Comparisons between global ¼° and zoom 1/15° in November 2005 Labrador temperature Subtropical gyre temperature salinity Global ¼° assim. Altimetry only Zoom 1/15° assim. Altimetry + in situ Independent In situ profile Levitus climatology for November (when far from in situ measurement)

13. Aiming at the 1/12° global system multivariate data assimilation in the 2° global system SLA only SLA + SST SST bias First results: January to July 1993 Temperature at 0N-140W TAO buoy Equipe R&D assimilation

14. Aiming at the 1/12° global system model improvements: North Atlantic SSH in 2003 MNATL4 MNATL12 Large improvement of the Gulf Stream separation and of the north Atlantic current penetration in the 1/12°