1. Ocean circulation around New Caledonia, downscaling of Pacific ocean climate and Impacts on issues relevant to island societies Patrick MARCHESIELLO IRD LEGOS 13 April, 2007

2. South-west Pacific circulation… Heading toward finer scales

3. Short story of Physical Oceanography in the New Caledonia -1969: a network of oceanographic observations using merchant ships was initiated by the IRD. The focus is on the large scale, although Hénin (1982, …) compiles the first climatology of the New Caledonia region. - 1994: The New Caledonia program ZoNéCo support the creation of a network of coastal stations. Delcroix and Lenormand (1997) compile regional data and show the characteristics of ENSO in the region. - 2000-2005: the downscaling effort is pushed further, with the development of the coastal network and a modeling activity. STCC

4. Climatology (1972-1992) Annual mean surface temperature (a) et salinity (b) computed from in- situ data collected from 1972 to 1992 in the New Caledonia region (Delcroix et Lenormand, 1997)

5. Caledonia upwelling discovery Hénin et Cresswell, 2005 - Seasonality ? - Alongshore extension ? Satellite SST for February 2003

6. Development of the coastal network (1994-2006) thermosalinographe SEA-BIRD SBE16 Onset temperature sensor Koumac Stations mooring Future station Phare Amédée F. Gallois

7. Seasonality of upwelling Alory et al., 2006 Seasonality of upwelling Alory et al., 2006 Eté Hiver Upwelling is apparent in summer only because the winter thermocline is deeper than the upwelling cell can reach Thermocline Upwelling cell nutriens nutrients 20 m 120 m 100 m 20 m 120 m

8. Refining our understanding of spatial variations: Models A regional model (ROMS) is embedded into a large scale model (MERCATOR) to perform a high resolution reanalysis (Marchesiello et al., 2006).

9. Model validation OnsetDepthTime serieLocation ROMS var (°C) Obs. var (°C) Bias (°C) RN° of Obs Sabine10 mNov98-Feb0415.9°S, 166.1°E 1.130.80 -0.26 0.78919 Surprises10 mSep97-Dec0418.3°S, 163.0°E 1.100.63 -0.12 0.73633 Uitoe 110 mSep99-Mar-0621.8°S, 166.1°E 0.650.55 -0.72 0.69633 Uitoe 235 mJul01-Mar-0621.8°S, 166.1°E 0.300.22 0.26 0.47816 Uitoe 362 mJul01-Mar-0621.8°S, 166.1°E 0.180.29 0.25 0.46669

10. Animation: J. Lefèvre

11. Circulation around the barrier reef Current measurments with a glider (Gourdeau, 2006) Surface Temperature and currents in ROMS (Atlas hydrodynamique, Vega et al., 2006) Température satellite

12. Applications: regional impacts of climate variability ENSO and climate: downscaling Impacts of climate changes: –Ecosystem, Fisheries –Tropical Cyclones –Tropical diseases: Dengue … Operational Oceanography: Survey and forecast Data distribution

13. Tuna-Environment relation IRD-CPS projects supported by ZoNéCo for 2007-2008 Integrated approach by coupling models: physics (ROMS) Plankton ecosystem (PISCES) Prey and tuna (SEAPODYM) K. Briand, ZoNéCo

14. Cyclones & Climate Project supported by ANR for 2007-2009 Downscaling mechanisms of ENSO and ENSO changes under global warming hypothesis. Impact on extreme events: Tropical Cyclones in the Caledonia region Simulation of Erica - March 2003

15. Climate and Dengue Climate and Dengue Modeling the Risk of dengue Regional modeling

16. Operational Oceanography: survey and forecast Survey: Real-time Web distribution of coastal station data Forecast: Web distribution of model forecast Support: project PREVIMER

17. Data Distribution Development of data server allowing access and extraction of model output and observation data for the Caledonia region