Ocean circulation around New Caledonia, downscaling of Pacific ocean climate and Impacts on issues...
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Transcript of Ocean circulation around New Caledonia, downscaling of Pacific ocean climate and Impacts on issues...
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
South-west Pacific circulation…
Heading toward finer scales
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
Climatology (1972-1992)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)
Caledonia upwelling discoveryCaledonia upwelling discovery
Hénin et Cresswell, 2005
- Seasonality ?- Alongshore extension ?
Satellite SST for February 2003
Development of the coastal Development of the coastal network (1994-2006)network (1994-2006)
thermosalinographe SEA-BIRD SBE16
Onset temperature sensor
Koumac
Stations
mooring
Futurestation
Phare Amédée F. Gallois
Seasonality of upwellingSeasonality of upwellingAlory et al., 2006Alory 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
Refining our understanding of Refining our understanding of spatial variations: Modelsspatial variations: Models
A regional model (ROMS) is embedded into a large scale model (MERCATOR) to perform a high resolution reanalysis (Marchesiello et al., 2006).
Model validationModel validation
Onset Depth Time serie Location ROMSvar(°C)
Obs. var(°C)
Bias (°C)
R N° of Obs
Sabine 10 m Nov98-Feb04 15.9°S, 166.1°E 1.13 0.80 -0.26 0.78 919
Surprises 10 m Sep97-Dec04 18.3°S, 163.0°E 1.10 0.63 -0.12 0.73 633
Uitoe 1 10 m Sep99-Mar-06 21.8°S, 166.1°E 0.65 0.55 -0.72 0.69 633
Uitoe 2 35 m Jul01-Mar-06 21.8°S, 166.1°E 0.30 0.22 0.26 0.47 816
Uitoe 3 62 m Jul01-Mar-06 21.8°S, 166.1°E 0.18 0.29 0.25 0.46 669
Animation:J. Lefèvre
Circulation around the barrier reefCirculation 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
Applications: regional impacts of Applications: regional impacts of climate variabilityclimate variability
• ENSO and climate: downscaling
• Impacts of climate changes:– Ecosystem, Fisheries– Tropical Cyclones– Tropical diseases: Dengue …
• Operational Oceanography: Survey and forecast
• Data distribution
Tuna-Environment relationTuna-Environment relation
160 165 170
-25
-20
-15
160 165 170
-25
-20
-15
160 165 170-2
5-2
0-1
5
Distribution: Nord-Ouestde la ZEE (Chesterfield –Lansdowne).
Distribution: Ouest de la ZEE (Chesterfield) et IlesLoyautés
Distribution: Sud de la grande Terre (englobantles Iles Loyautés et l’Iledes Pins) .
Thon germon
Thon jaune
Thon obèse
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
Cyclones & ClimateCyclones & 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
Climate and DengueClimate and Dengue
Modeling the Risk of dengue Regional modeling
Operational Oceanography:Operational Oceanography:survey and forecastsurvey and forecast
Survey:Real-time Web distribution of coastal station data
Forecast:Web distribution of model forecast
Support: project PREVIMER
Data DistributionData Distribution1. Choix de la donnée
2. Selection de la région
3. Affichage graphique du résultat
Development of data server allowing access and extraction of model output and observation data for the Caledonia region