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Black (1851). S outhwest P ac I fic Ocean C irculation and Climate E xperiment: SPICE A. Ganachaud JISAO/PMEL/NOAA LEGOS / IRD Nouméa-Toulouse Laboratoire d’Etudes Géophysiques et d’Océanographie Spatiale. W. Kessler (PMEL/NOAA) G. Brassington(BOM) S. Wijffels, K. Ridgway, W. Cai (CSIRO)
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Black (1851) Southwest PacIfic Ocean Circulation and Climate Experiment:SPICEA. Ganachaud JISAO/PMEL/NOAALEGOS / IRD Nouméa-ToulouseLaboratoire d’Etudes Géophysiques et d’Océanographie Spatiale W. Kessler (PMEL/NOAA) G. Brassington(BOM) S. Wijffels, K. Ridgway, W. Cai (CSIRO) N. Holbrook (MU) P. Sutton, M. Bowen (NIWA) B. Qiu, A. Timmermann (UH) D. Roemmich, J. Sprintall (SIO), H. Diamond (NOAA) S. Cravatte, L. Gourdeau (LEGOS) P. Eastwood (SOPAC/Fiji) T. Aung (USP/Fiji)
Outline A. Thermocline watersB. SPCZC. Impacts D. Context and strategy SOLOMON IS. PNG Solomon Sea Coral Sea Fiji VANUATU N. CALEDONIA AUSTRALIA Tasman Sea NEW ZEALAND
R/V ORSOM III, 1956 interisland flows Rotschi, Legand, Hamon Interests in the Coral and Tasman Sea circulation Cronulla, August 1958Conference on the Coral and Tasman Sea Oceanography Cairns, August 2005Workshop on theSouthwest Pacific Ocean Circulation and its relation with Climate
Decadal influences: Thermocline water connection between the subduction zone of the South East Pacific and the equator Lines show geostrophic streamlines on the isopycnal (courtesy B. Kessler)
A-The South Pacific "Thermocline" waters South Equatorial Current Salinity maximumZ=100:300m Temperature/salinity diagram(Argo floats, 2007)
Thermocline water currents0-300m 70 % EUC waters ~15 Sv + ~25 Sv
Thermocline water currents0-300m ~15 Sv + ~25 Sv ~10 Sv
Thermocline water currents0-300m 3-Solomon Sea 1-Inflows 2-Tasman Sea
Thermocline waters: 1-inflow to the Coral Sea Formation of 3 "jets" Bifurcation (northward bias in GCM/CGCMs) Outflows and budget Bifurcation: Qu and Lindstrom 2002 Kessler and Gourdeau 2006, 2007
Thermocline waters: 2-EAC and EAUC Ridgway and Dunn, (2003); Cai et al. (2003); Bowen et al. (2005)
Thermocline waters: 2-EAC and EAUC Ridgway and Dunn, (2003); Cai et al. (2003); Bowen et al. (2005) Variability dominates the mean flow • Inflows/outflows variations; eddy dynamics • Tasman Outflow linkage between S. Pacific gyre and Indian/global circulation • Heat balance in the Tasman Sea SSH variability C. Ken Ridgway
Thermocline waters: 3-North Coral Sea:A WBC pathway to feed the EUC and ITF CARS dynamic Ht relative to 2000m(C. W. Kessler) ST GEORGES SOLOMON VITIAZ NVJ NCJ Quasi undocumented circulation WEPOCS cruises, 1985 (Lindstrom et al., 1987; Tsuchiya et al., 1989; Fine et al., 1994) • Narrow straits, difficult to model • Strong WBC, mixing • Strong variability: monsoon, ENSO
The Southwest Pacific Atmosphere SPCZ Trade winds Trade winds A A
B-South Pacific Convergence Zone 20th century climate model COADS cloudiness 1960-1970 High convective activity, precipitation, wind convergence-Dominant convective feature in the Southern Hemisphere-Substantial variability: (intra) seasonal; interannual;Equatorward shift 1976-Unresolved southward bend, poorly modelled -Strong local effects (SSS, oceanic heat content)
ERSST data (1944-2005) C-Ocean and climate impacts on environmentin the southwest Pacific Consequences of ocean and climate fluctuations: • Biodiversity, Coral reefs • Freshwater-agriculture and health • Tropical cyclones • Sea surface height Pacific Island Countries: Fragile ecosystems, low-lying populated areas, isolated places Australia and New Zealand: Climate depends on heat content in the Tasman Sea Freshwater resources critical Important changes in biodiversity SST Trend (°C/century)
D. Context and strategy:unadapted observations Sokolov and Rintoul (2000) Qu and Lindstrom (2002) Ridgway and Dunn (2003) Maximenko (2005) Distribution of the (T,S) casts (Ridgway and Dunn, 2003) Active Argo floats on 11/15/2007 Sattelite-derived surface currents
D. Context and strategy:existing large scale programs UW/CSIRO/IRD IRD SIO/CSIRO/IRD BOM/MF IMOS/Bluewater and climate BOM/IRD
D. Context and strategy:SPICE benefits Observations: Ocean and O-A Modelling: Ocean and coupled • Related programs: • Operational oceanography • Meteorology • Local applications • Global observations Modelling: Atmosphere Observations: Atmosphere
D. Context and strategy:SPICE benefits Observations: Ocean and O-A Modelling: Ocean and coupled • Related programs: • Operational oceanography • Meteorology • Local applications • Global observations SPICE: Coordination Data sharing National funding Modelling: Atmosphere ? Observations: Atmosphere
Modelling strategy: regional zooms • Help to design observation / monitoring program • Sensitivity experiments • Regional applications CSIRO/BOM UH/LOCEAN UH/LEGOS IRD/NIWA IRD/CNRS/CNES/IFREMER/METEO-FRANCE/SHOM
Regional field experiment 2010 2007+ 2007+ 2005+ 2004+ 2008 2007+ 2008 running TBS TBS
SPICE Challenges "Add-on" Costs 2008-2011 1-Fieldwork: Shiptime: 1.5month/yr Wet measurements: $1.6M/yr HRXT, Air-sea fluxes: funded 2-Modelling: Infrastructures exist Specific analyses costs
Main objectives and timetable A. Ganachaud, W. Kessler, G. Brassington, S. Wijffels, K. Ridgway, W. Cai, N. Holbrook, M. Bowen, P. Sutton, A. Timmermann, B. Qiu, D. Roemmich, J. Sprintall, H. Diamond, S. Cravatte, L. Gourdeau, P. Eastwood, T. Aung Objective 1-Role of the southwest Pacific in CGCMS (SPCZ, …) 2-Air-sea fluxes and currents 3-Monitoring key quantities 4-Local impacts 2004-2007 -SEC inflow (cruise and glider) -Gyre dynamics and jets -Experimental monitoring Solomon Sea -Model downscaling (ROMS-type) -Operational prototypes -SSS-based analyses 2008-2010 -Modelling experiments-Major SPCZ experiments ? -SEC infow monitoring -Solomon Sea exploration (model, cruise, moorings, gliders) -EAC monitoring -VOS with AWS Hull SST -Experimental monitoring SEC and Solomon Straits -Regionally oriented applications and training
SPICE and CLIVAR A. Ganachaud, W. Kessler, G. Brassington, S. Wijffels, K. Ridgway, W. Cai, N. Holbrook, M. Bowen, P. Sutton, A. Timmermann, B. Qiu, D. Roemmich, J. Sprintall, H. Diamond, S. Cravatte, L. Gourdeau, P. Eastwood, T. Aung Relevance 1-Identify key features and their impact on climate simulation on seasonal to decadal timescales 2-Understand pertinent air-sea fluxes and oceanic currents (LLWBCs) to improve climate modelling and prediction Legacy 1- Long term monitoring of selected features (SST, straits…) 2-Training and transition to local benefits (application of data or operational products) "Add-on" Costs 2008-2011 1-Fieldwork: Shiptime: 1.5month/yr Wet measurements: $1.6M/yr HRXT, Air-sea fluxes: funded 2-Modelling: Infrastructures exist Specific analyses costs
Interannual influences: ENSO and cyclones La Niña -Tropical Cyclone Density Courtesy J. Salinger
Downscaling…and upscaling ROMS, 1/12°, nested (Courtesy A. Vega, IRD) J. Lefevre, IRD
ERSST data (1944-2005) 2-Ocean and climate impacts on environmentin the southwest Pacific Ocean and climate fluctuations: • Decadal gyre spin-up: 2°C increase in Tasmania • Short time scales: cyclone trajectories or storm surges SST Trend (°C/century) Global Climate Model Forecast Mk3 2070 Surface Temperature O’Farrell, 2005
Giese et al. 2002: T on sigma=25 SST AUSTRALIA UPWELLING SST TO EAST TO WBC Equator 8°S, East to West 2-Decadal influences: Thermocline water connection A temperature anomaly on sigma=25 (EUC core) from the Southeast Pacific preceeds Nino-3 by 7 years Giese et al. 2002, Schneider 2004, Luo et al. 2005 Izumo et al., 2002: Origins of Nino 3 waters
SWPacific and ClimateEAC and the Tasman Front The Southward Pacific WBC which closes the subtropical gyre(Ridgway and Dunn, 2003)
Glider measurements, 2005(Gourdeau, Kessler, Davis, Sherman) 580 CTD profiles down to 600 meters Absolute geostrophic velocity field Temperature Salinity NVJ Gourdeau et al. 2007 NJC
1-Modeling strategy: regional zooms • Help to design observation then monitoring program • Sensitivity experiments • Regional applications High resolution global/regional ocean, atmosphere and climate models Blue Link (CSIRO/BOM) ROMS/Mercator (IRD Nouméa)
Towards a large scale field experimentExisting observations Sokolov and Rintoul (2000) Qu and Lindstrom (2002) Ridgway and Dunn (2003) Maximenko (2005) Active Argo floats on 08/17/2007 Distribution of the (T,S) casts (Ridgway and Dunn, 2003) Sattelite-derived surface currents
ERSST data (1944-2005) 2: EAC and the Tasman Front Interannual Variability (Sea level anomaly) 1996 2000 SST Trend (°C/century) Global Climate Model Forecast Mk3 2070 Surface Temperature O’Farrell, 2005
Interannual influences: thermocline transport modulation Courtesy B. Kessler • Interannual time scale: El Niño influences the SW Pacific Circulation (Delcroix and hénin, 1989; Sprintall et al., 1995; Gouriou and Delcroix, 2002)
3-North Coral Sea:A WBC pathway to feed the EUC and ITF • Narrow straits, difficult to model • Strong WBC, mixing • Strong variability: monsoon, ENSO 0-200m SADCP currents, May 1993 Blue: 2007 glider trajectory(C. W. Kessler)
Main objectives and timetable A. Ganachaud, W. Kessler, G. Brassington, S. Wijffels, K. Ridgway, W. Cai, N. Holbrook, M. Bowen, P. Sutton, A. Timmermann, B. Qiu, D. Roemmich, J. Sprintall, H. Diamond, S. Cravatte, L. Gourdeau, P. Eastwood, T. Aung Objective 1-Role of the southwest Pacific in CGCMS (SPCZ, …) 2-Air-sea fluxes and currents 3-Monitoring key quantities 4-Local impacts 2004-2007 -SEC inflow (cruise and glider) -Gyre dynamics and jets -Experimental monitoring Solomon Sea -Model downscaling (ROMS-type) -Operational prototypes -SSS-based analyses 2008-2010 -Modelling experiments-Major SPCZ experiments ? -SEC infow monitoring -Solomon Sea exploration (model, cruise, moorings, gliders) -EAC monitoring -VOS with AWS Hull SST -Experimental monitoring SEC and Solomon Straits -Regionally oriented applications and training SPCZ/ocean Session AGU 2007
1-Thermocline water inflow to the Coral Sea 162.5°E zonal velocity (blue=westward) TO EAC TO NQC NVJ NCJ SCJ Bifurcation: Qu and Lindstrom 2002 Kessler and Gourdeau 2006, 2007 Formation of 3 "jets" Bifurcation (northward bias in GCM/CGCMs) Outflows and budget
Towards a regional field experiment 2005+ 2004+ 2008
Towards a regional field experiment 2010 2007+ 2007+ 2005+ 2004+ 2008
Towards a regional field experiment 2010 2007+ 2007+ 2005+ 2004+ 2008 2007+ 2008 running TBS TBS
SPICE Challenges Modelling strategy Existing programs Ocean field experiment SPCZ process study (?)