La salinité de surface, thème fédérateur d’OLVAC Etudes s’appuyant sur le SO SSS, les satellites SMOS/Aquarius, la modélisation Thématique présente sur tous les chantiers géographiques OLVAC, à différentes échelles spatio-temporelles, centrale dans plusieurs thèses tendances climatiques long terme impact des fleuves dynamique IOD dynamique saisonnière circulation australe climat régional dynamique ENSO
ENSO-related SSS changes Eastern Pacific El Niño Central Pacific El Niño SST SSS Different SSS anomalies near the eastern edge of WP fresh pool and under SPCZ (Singh, Delcroix & Cravatte, 2011) 2 2
Associated equatorial mechanisms Mixed layer salt budget in forced model: advection term not extending eastward of dateline in CP Niño no eastern precipitation forcing in CP Niño strong subsurface forcing in EP Niño 1996-1998 Eastern Pacific El Niño 2001-2004 Central Pacific El Niño pss/yr (Hasson, Delcroix & Dussin, 2013)
East Pacific Fresh Pool seasonal cycle M O SMOS can monitor the fresh pool Wind/Rain JAS Surface Currents JFM Panama gap wind Upwelling Summer rain => SSS minimum, fresh pool building Westward advection of fresh pool by SEC Ekman pumping => upwelling in Panama Bight, fresh pool destruction (Alory, Maes, Delcroix, Reul & Illig, 2012)
Impact of river discharges in Bay of Bengal Ganges + Brahmaputra SSS with seasonal runoff + interannual runoff anomaly resulting SST anomaly 1998: strong discharge Model simulations with or without interannual runoff anomaly (Durand, Papa, Rahman & Bala, 2011)
Indian Ocean Dipole SSS signature SMOS SSS 12/2011 – 12/2010 IOD+ IOD- 2010 2012 Largest year-to-year signal in SMOS data, related to IOD-/IOD+ succession Validation SMOS SSS in situ SSS WOA SSS Both data and model agree on dominant role of advection (Durand, Alory, Reul & Dussin, en cours)
Tropical Atlantic SSS budget from mixed layer model Climatological model validation Seasonal balance in selected regions Dominant processes for mean state (Da-Allada, Alory, Dupenhoat, Kestenare, Durand & Hounkonnou, 2013)
Interannual variations in SURVOSTRAL SubAntarctic Zone Correlation Maria Is TSG 2012 2000 1993 SAZ : SSS – Seasonal mean (DJFM) SAZ AZ Southward penetration of Tasman Sea inflow (Morrow & Kestenare, en cours)
Global SSS trends (1970-2002) Obs Mean SSS Observed trends reflect the « wet gets wetter, dry gets drier » Clausius-Clapeyron effect Local effect + mean currents Models capture the increasing Pacific-Atlantic contrast despite biases (double ITCZ) Obs SSS trend CMIP3 models SSS trend (Terray, Corre, Cravatte, Delcroix, Reverdin & Ribes, 2012)
Conclusion Bon week-end! Poursuivre les observations sur le long-terme (in situ + satellite) Bonne synergie entre SO et recherche associée (CNAP) Transversalité: cycle de l’eau, couplage océan-atmosphère... Bon week-end!