Ocean Dynamics

, Volume 63, Issue 11–12, pp 1203–1212 | Cite as

SMOS reveals the signature of Indian Ocean Dipole events

  • Fabien Durand
  • Gaël Alory
  • Raphaël Dussin
  • Nicolas Reul
Article

Abstract

The tropical Indian Ocean experiences an interannual mode of climatic variability, known as the Indian Ocean Dipole (IOD). The signature of this variability in ocean salinity is hypothesized based on modeling and assimilation studies, on account of scanty observations. Soil Moisture and Ocean Salinity (SMOS) satellite has been designed to take up the challenge of sea surface salinity remote sensing. We show that SMOS data can be used to infer the pattern of salinity variability linked with the IOD events. The core of maximum variability is located in the central tropical basin, south of the equator. This region is anomalously salty during the 2010 negative IOD event, and anomalously fresh during the 2011 positive IOD event. The peak-to-peak anomaly exceeds one salinity unit, between late 2010 and late 2011. In conjunction with other observational datasets, SMOS data allow us to draw the salt budget of the area. It turns out that the horizontal advection is the main driver of salinity anomalies. This finding is confirmed by the analysis of the outputs of a numerical model. This study shows that the advent of SMOS makes it feasible the quantitative assessment of the mechanisms of ocean surface salinity variability in the tropical basins, at interannual timescales.

Keywords

SSS Indian Ocean Dipole SMOS ARGO ENSO 

Notes

Acknowledgements

Thermosalinograph data were collected and processed by the French SSS Observation Service (www.legos.obs-mip.fr/observations/sss). CNES partly funded these activities in the frame of the Centre Aval de Traitement des Données SMOS (CATDS) and of the SMOS TOSCA projects. The numerical model simulation was produced as part of the DRAKKAR project; we are grateful to Jean-Marc Molines and Bernard Barnier for their contribution. We are thankful to Thierry Delcroix and Clément de Boyer Montégut for fruitful discussions.

References

  1. Alory G, Maes C, Delcroix T, Reul N, Illig S (2012) Seasonal dynamics of sea surface salinity off Panama: the far Eastern Pacific Fresh Pool. J Geophys Res 117, C04028. doi:10.1029/2011JC007802 CrossRefGoogle Scholar
  2. Antonov JI, Locarnini RA, Boyer TP, Mishonov AV, Garcia HE (2006) World Ocean Atlas 2005, volume 2. In: Levitus S (ed) Salinity. NOAA Atlas NESDIS 62, U.S. Government Printing Office, Washington, D.C, p 182Google Scholar
  3. Blanke B, Delecluse P (1993) Variability of the tropical Atlantic Ocean simulated by a general circulation model with 2 different mixed layer physics. J Phys Oceanogr 23(7):1363–1388CrossRefGoogle Scholar
  4. Bonjean F, Lagerloef GSE (2002) Diagnostic model and analysis of the surface currents in the tropical Pacific Ocean. J Phys Oceanogr 32(10):2938–2954CrossRefGoogle Scholar
  5. Boutin J, Martin N, Yin X, Reul N, Spurgeon P (2012) First assessment of SMOS data over open ocean: part II-sea surface salinity. IEEE Transactions on Geoscience and Remote Sensing, 50(5). Part 1:1662–1675Google Scholar
  6. de Boyer MC, Madec G, Fischer AS, Lazar A, Iudicone D (2004) Mixed layer depth over the global ocean: an examination of profile data and a profile-based climatology. J Geophys Res 109:C12003. doi:10.1029/2004JC002378 CrossRefGoogle Scholar
  7. Da-Allada CY, Alory G, du Penhoat Y, Kestenare E, Durand F, Hounkonnou N (2013) Seasonal mixed-layer salinity balance in the tropical Atlantic Ocean: mean state and seasonal cycle. J Geophys Res. doi:10.1029/2012JC008357 Google Scholar
  8. Drakkar Group (2007) Eddy-permitting ocean circulation hindcasts of past decades. CLIVAR Exchanges 42 12(3):8–10Google Scholar
  9. Ferry N, Parent L, Garric G, Drevillon M, Desportes C, Bricaut C, Hernandez F (2011) Scientific validation report (ScVR) for V1 reprocessed analysis and reanalysis: GLORYS2V1. MyOcean FP7-SPACE-2007-1 project, report MYO-WP04-ScCV-rea-MERCATOR_V1RepGoogle Scholar
  10. Font J, Camps A, Borges A, Martín-Neira M, Boutin J, Reul N, Kerr YH, Hahne A, Mecklenburg S (2010) SMOS: the challenging sea surface salinity measurement from space. Proc IEEE 98(5):649–665CrossRefGoogle Scholar
  11. Grunseich G, Subrahmanyam B, Murty VSN, Giese BS (2011) Sea surface salinity variability during the Indian Ocean Dipole and ENSO events in the tropical Indian Ocean. J Geophys Res 116, C11013. doi:10.1029/2011JC007456 CrossRefGoogle Scholar
  12. Hasson A, Delcroix T, Dussin R (2013) An assessment of the mixed layer salinity budget in the tropical Pacific Ocean. Observations and modelling (1990–2009). Ocean Dyn 63(2–3):179–197. doi:10.1007/s10236-013-0596-2.
  13. Jensen TG (2007) Wind–driven response of the northern Indian Ocean to climate extremes. J Clim 20:2978–2993. doi:10.1175/JCLI4150.1 CrossRefGoogle Scholar
  14. Keerthi MG, Lengaigne M, Vialard J, de Boyer MC, Muraleedharan PM (2012) Interannual variability of the Tropical Indian Ocean mixed layer depth. Clim Dyn 40:743–759CrossRefGoogle Scholar
  15. Lee T, Fukumori I, Tang B (2004) Temperature advection: internal versus external processes. J Phys Oceanogr 34:1936–1944CrossRefGoogle Scholar
  16. Madec G (2008) NEMO reference manual, ocean dynamics component. Note du pôle de modélisation, IPSL, France No. 27 ISSN No. 1288–1619.Google Scholar
  17. Masson S, Delecluse P, Boulanger JP, Menkes C (2002) A model study of the seasonal variability and formation mechanisms of barrier layer in the eastern equatorial Indian Ocean. J Geophys Res 107:8017. doi:10.1029/2001JC000,832 CrossRefGoogle Scholar
  18. Masson S, Menkes C, Delecluse P, Boulanger JP (2003) Impacts of the salinity on the eastern Indian Ocean during the termination of the fall Wyrtki Jet. J Geophys Res 108:3067. doi:10.1029/2001JC000,833 CrossRefGoogle Scholar
  19. Masson S, Boulanger JP, Menkes C, Delecluse P, Yamagata T (2004) Impact of salinity on the 1997 Indian Ocean Dipole event in a numerical experiment. J Geophys Res 109, C02002. doi:10.1029/2003JC001807 CrossRefGoogle Scholar
  20. Mecklenburg S, Kerr Y, Font J, Hahne A. (2008) The Soil Moisture and Ocean Salinity (SMOS) mission—an overview. Geophysical Research Abstracts, Vol. 10Google Scholar
  21. Mecklenburg S, Drusch M, Kerr YH, Font J, Martin-Neira M, Delwart S, Buenadicha G, Reul N, Daganzo-Eusebio E, Oliva R, Crapolicchio R (2012) ESA’s soil moisture and ocean salinity mission: mission performance and operations. IEEE Transactions on Geoscience and Remote Sensing 50(5). Part 1:1354–1366Google Scholar
  22. McPhaden MJ, Meyers G, Ando K, Masumoto Y, Murty VSN, Ravichandran M, Syamsudin F, Vialard J, Yu L, Yu W (2009) RAMA: the research moored array for African-Asian-Australian monsoon analysis and prediction. Bull Am Meteorol Soc 90:459–480CrossRefGoogle Scholar
  23. Nidheesh AG, Lengaigne M, Vialard J, Unnikrishnan AS, Dayan H (2012) Decadal and long-term sea level variability in the tropical Indo-Pacific Ocean. Clim Dyn. doi:10.1007/s00382-012-1463-4 Google Scholar
  24. Rao RR, Sivakumar R (2003) Seasonal variability of sea surface salinity and salt budget of the mixed layer of the north Indian Ocean. J Geophys Res 108:3009. doi:10.1029/2001JC000907 CrossRefGoogle Scholar
  25. Ratheesh S, Mankad B, Basu S, Kumar R, Sharma R (2013) Assessment of satellite-derived sea surface salinity in the Indian Ocean. IEEE Geosci Remote Sens Lett 10(3):428–431. doi:10.1109/LGRS.2012.2207943 CrossRefGoogle Scholar
  26. Reul N, Tenerelli J, Boutin J, Chapron B, Paul F, Brion E, Gaillard F, Archer O (2012) Overview of the first SMOS sea surface salinity products. Part I: quality assessment for the second half of 2010. IEEE Transactions on Geoscience and Remote Sensing 50(5):1636–1647CrossRefGoogle Scholar
  27. Reul N, Fournier S, Boutin J, Hernandez O, Maes C, Chapron B, Alory G, Quilfen Y, Tenerelli J, Morisset S, Kerr Y, Mecklenburg S, Delwart S (2013) Sea surface salinity observations from space with the SMOS satellite: a new means to monitor the marine branch of the water cycle. Surv Geophys. doi:10.1007/s10712-013-9244-0 Google Scholar
  28. Reverdin G, Cadet DL, Gutzler D (1986) Interannual displacements of convection and surface circulation over the equatorial Indian Ocean. QJRMS 112(471):43–67CrossRefGoogle Scholar
  29. Saji NH, Goswami BN, Vinayachandran PN, Yamagata T (1999) A dipole mode in the tropical Indian Ocean. Nature 401:360–363Google Scholar
  30. Shenoi SSC, Saji PK, Almeida AM (1999) Near-surface circulation and kinetic energy in the tropical Indian Ocean derived from Lagrangian drifters. J Mar Res 57(6):885–907CrossRefGoogle Scholar
  31. Subrahmanyam B, Grunseich G, Nyadjro ES (2012) Preliminary SMOS salinity measurements and validation in the Indian Ocean. IEEE Trans Geosci Remote Sens. doi:10.1109/TGRS.2012.2199122 Google Scholar
  32. Thompson B, Gnanaseelan C, Salvekar PS (2006) Variability in the Indian Ocean circulation and salinity and its impact on SST anomalies during dipole events. J Mar Res 64:853–880. doi:10.1357/002224006779698350 CrossRefGoogle Scholar
  33. Vialard J, Delecluse P, Menkes C (2002) A modeling study of salinity variability and its effects in the tropical Pacific Ocean during the 1993–1999 period. J Geophys Res Oceans 107(C12). doi:10.1029/2000jc000758
  34. Vinayachandran PN, Nanjundiah RS (2009) Indian Ocean sea surface salinity variations in a coupled model. Clim Dyn 33:245–263. doi:10.1007/s00382-008-0511-6 CrossRefGoogle Scholar
  35. Webster PJ, Moore AM, Loschnigg JP, Leben RR (1999) Coupled ocean–atmosphere dynamics in the Indian Ocean during 1997–98. Nature 401:356–360. doi:10.1038/43848 CrossRefGoogle Scholar
  36. Yu L, Jin X, Weller R A (2008) Multidecade Global Flux Datasets from the Objectively Analyzed Air-sea Fluxes (OAFlux) Project: latent and sensible heat fluxes, ocean evaporation and related surface meteorological variables. Woods Hole Oceanographic Institution, OAFlux Project Technical Report. OA-2008-01, 64 pages. Woods Hole. Massachusetts.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Fabien Durand
    • 1
  • Gaël Alory
    • 1
  • Raphaël Dussin
    • 2
  • Nicolas Reul
    • 3
  1. 1.LEGOS, UMR 5566, CNRS-CNES-IRD-UPSUniversité de Toulouse 3ToulouseFrance
  2. 2.LEGI, Domaine UniversitaireGrenobleFrance
  3. 3.LOS, Ifremer, Centre MéditerranéeLa Seyne-sur-MerFrance

Personalised recommendations