Southwest Pacific Ocean Circulation and Climate Experiment: SPICE A

Home , Tasman Outflow

Southwest PacIfic Ocean Circulation and Climate Experiment: 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) 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) Black (1851) T. Aung (USP/Fiji) Outline A. Thermocline waters B. SPCZ

SOLOMON IS. C. Impacts PNG Solomon D. Context and strategy Sea VANUATU Coral Fiji Sea N. CALEDONIA

AUSTRALIA

Tasman Sea NEW ZEALAND Rotschi, Legand, Hamon Interests in the Coral and Tasman Sea circulation

R/V ORSOM III, Cronulla, August 1958 1956 Conference on the Coral and Tasman Sea interisland Oceanography flows

Cairns, August 2005 Workshop on the Southwest 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 maximum Z=100:300m

Temperature/salinity diagram (Argo floats, 2007) Thermocline water currents: 0-300m

~25 Sv Thermocline water currents 0-300m

70 % EUC waters ~15 Sv + ~25 Sv Thermocline water currents 0-300m

~15 Sv + ~25 Sv

~10 Sv Thermocline water currents 0-300m

3-Solomon Sea

1-Inflows

2-Tasman Sea Thermocline waters: 1-inflow to the Coral Sea

1. Formation of 3 "jets" 2. Bifurcation (northward bias in GCM/CGCMs) 3. 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)

SSH variability C. Ken Ridgway

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 Thermocline waters: 3-North Coral Sea: A WBC pathway to feed the EUC and ITF

SOLOMON VITIAZ GEORGES

NVJ

Quasi undocumented circulation NCJ

WEPOCS cruises, 1985 CARS dynamic Ht relative to 2000m (C. W. Kessler)

(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

COADS cloudiness 1960-1970 20th century climate model

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) C-Ocean and climate impacts on environment in 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 SST Trend (°C/century) places ERSST data (1944-2005) Australia and New Zealand:

Climate depends on heat content in the Tasman Sea

Freshwater resources critical

Important changes in biodiversity 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 Sattelite-derived surface currents 11/15/2007 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: Related programs: Ocean and coupled •Operational oceanography •Meteorology •Local applications Modelling: •Global observations Atmosphere

Observations: Atmosphere D. Context and strategy: SPICE benefits

Observations: Ocean and O-A

Modelling: Related programs: Ocean and coupled SPICE: •Operational oceanography Coordination •Meteorology Data sharing •Local applications Modelling: National funding •Global observations Atmosphere ? Observations: Atmosphere Modelling strategy: regional zooms

1. Help to design observation / monitoring program 2. Sensitivity experiments 3. Regional applications

CSIRO/BOM UH/LOCEAN

UH/LEGOS

IRD/NIWA

IRD/CNRS/CNES/IFREMER/METEO- FRANCE/SHOM Regional field experiment

2010

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