Climate Dynamics

, Volume 43, Issue 3–4, pp 709–736 | Cite as

Salinity changes in the World Ocean since 1950 in relation to changing surface freshwater fluxes

  • Nikolaos Skliris
  • Robert Marsh
  • Simon A. Josey
  • Simon A. Good
  • Chunlei Liu
  • Richard P. Allan


Global hydrographic and air–sea freshwater flux datasets are used to investigate ocean salinity changes over 1950–2010 in relation to surface freshwater flux. On multi-decadal timescales, surface salinity increases (decreases) in evaporation (precipitation) dominated regions, the Atlantic–Pacific salinity contrast increases, and the upper thermocline salinity maximum increases while the salinity minimum of intermediate waters decreases. Potential trends in E–P are examined for 1950–2010 (using two reanalyses) and 1979–2010 (using four reanalyses and two blended products). Large differences in the 1950–2010 E–P trend patterns are evident in several regions, particularly the North Atlantic. For 1979–2010 some coherency in the spatial change patterns is evident but there is still a large spread in trend magnitude and sign between the six E–P products. However, a robust pattern of increased E–P in the southern hemisphere subtropical gyres is seen in all products. There is also some evidence in the tropical Pacific for a link between the spatial change patterns of salinity and E–P associated with ENSO. The water cycle amplification rate over specific regions is subsequently inferred from the observed 3-D salinity change field using a salt conservation equation in variable isopycnal volumes, implicitly accounting for the migration of isopycnal surfaces. Inferred global changes of E–P over 1950–2010 amount to an increase of 1 ± 0.6 % in net evaporation across the subtropics and an increase of 4.2 ± 2 % in net precipitation across subpolar latitudes. Amplification rates are approximately doubled over 1979–2010, consistent with accelerated broad-scale warming but also coincident with much improved salinity sampling over the latter period.


Salinity Freshwater flux Evaporation Precipitation Hydrological cycle 



This study was part of the “HydrOlogical cYcle Understanding vIa Process-bAsed GlObal Detection, Attribution and prediction (Horyuji PAGODA)”, supported by the UK Natural Environment Research Council as part of the “Changing Water Cycle” programme (Grant No. NE/I006222/1). Simon Good was supported by the Joint DECC and Defra Integrated Climate Programme, DECC/Defra (GA01101). We are grateful to two anonymous referees for their extremely thorough and constructive reviews.


  1. Adler RF, Huffman GJ, Chang A, Ferraro R, Xie P, Janowiak J, Rudolf B, Schneider U, Curtis S, Bolvin D, Bolvin D, Gruber A, Susskind J, Arkin P, Nelkin EJ (2003) The version 2.1 global precipitation climatology project (GPCP) monthly precipitation analysis (1979—present). J Hydrometeorol 4(6):1147–1167CrossRefGoogle Scholar
  2. Allan RP, Soden BJ, John VO, Ingram W, Good P (2010) Current changes in tropical precipitation. Environ Res Lett 5:025205. doi: 10.1088/1748-9326/5/2/025205 CrossRefGoogle Scholar
  3. Alory GSW, Wijffels S, Meyers G (2007) Observed temperature trends in the Indian Ocean over 1960–1999 and associated mechanism. Geophys Res Lett 34:L02606. doi: 10.1029/2006GL028044 CrossRefGoogle Scholar
  4. Andersson A, Klepp C, Fennig K, Bakan S, Hartmut Grassl H, Jörg Schulz J (2011) Evaluation of HOAPS-3 ocean surface freshwater flux components. J Appl Meteor Climatol 50:379–398CrossRefGoogle Scholar
  5. Antonov JI, Levitus S, Boyer T (2002) Steric sea level variations during 1957–1994: importance of salinity. J Geophys Res 107(C12):8013. doi: 10.1029/2001JC000964 CrossRefGoogle Scholar
  6. Arkin PA, Smith TM, Sapiano MRP, Janowiak J (2010) The observed sensitivity of the global hydrological cycle to changes in surface temperature. Environ Res Lett 5:035201. doi: 10.1088/1748-9326/5/3/035201 CrossRefGoogle Scholar
  7. Belkin IM (2004) Propagation of the “great salinity anomaly” of the 1990s around the northern North Atlantic. Geophys Res Lett 31:L08306. doi: 10.1029/2003GL019334 CrossRefGoogle Scholar
  8. Belkin IM, Levitus S, Antonov J, Malmberg SA (1998) “Great Salinity Anomalies” in the North Atlantic. Progr Oceanogr 41:1–68. doi: 10.1016/S0079-6611(98)00015-9 CrossRefGoogle Scholar
  9. Bethoux JP, Gentili B (1999) Functioning of the Mediterranean Sea: past and present changes related to freshwater input and climate changes. J Mar Syst 20:33–47CrossRefGoogle Scholar
  10. Bindoff NL, McDougall TJ (1994) Diagnosing climate change and ocean ventilation using hydrographic data. J Phys Oceanogr 24:1137–1152CrossRefGoogle Scholar
  11. Bindoff NL, Willebrand J, Artale V et al (2007) Observations: oceanic climate change and sea level. In: Solomon S et al (eds) Climate change 2007: the physical science basis. Contribution of the working group I to the fourth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, pp 385–432Google Scholar
  12. Boyer TP, Levitus S, Antonov JI, Locarnini RA, Garcia HE (2005) Linear trends in salinity for the World Ocean, 1955–1998. Geophys Res Lett 32:L01604. doi: 10.1029/2004GL021791 CrossRefGoogle Scholar
  13. Boyer TP, Levitus S, Antonov JI, Locarnini RA, Mishonov A, Garcia HE, Josey SA (2007) Changes in freshwater content in the North Atlantic Ocean 1955‐2006. Geophys Res Lett 34:L16603. doi: 10.1029/2007GL030126 CrossRefGoogle Scholar
  14. Chou C, Neelin JD, Chen C-A, Tu J-Y (2009) Evaluating the “rich get richer” mechanism in tropical precipitation change under global warming. J Clim 22:1982–2005CrossRefGoogle Scholar
  15. Compo GP, Whitaker JS, Sardeshmukh PD et al (2011) The twentieth century reanalysis project. Q R Meteorol Soc 137:1–28. doi: 10.1002/qj.776 CrossRefGoogle Scholar
  16. Cravatte S, Delcroix T, Zhang D, McPhaden M, LeLoup J (2009) Observed freshening and warming of the western Pacific Warm Pool. Clim Dyn 33:565–589. doi: 10.1007/s00382-009-0526-7 CrossRefGoogle Scholar
  17. Curry R, Mauritzen C (2005) Dilution of the northern North Atlantic Ocean in recent decades. Science 308:1772–1774. doi: 10.1126/science.1109477 CrossRefGoogle Scholar
  18. Curry RG, McCartney MS (2001) Ocean gyre circulation changes associated with the North Atlantic Oscillation. J Phys Oceanogr 31:3374–3400. doi: 10.1175/1520-0485(2001)031<3374:OGCCAW>2.0.CO;2 CrossRefGoogle Scholar
  19. Curry R, Dickson B, Yashayaev I (2003) A change in the freshwater balance of the Atlantic Ocean over the past four decades. Nature 426:826–829. doi: 10.1038/nature02206 CrossRefGoogle Scholar
  20. Dee DP, Uppala SM, Simmons AJ et al (2011) The ERA-Interim reanalysis: configuration and performance of the data assimilation system. Q J R Meteorol Soc 137:553–597. doi: 10.1002/qj.828 CrossRefGoogle Scholar
  21. Delcroix T, Alory G, Cravatte S, Corrège T, McPhaden M (2011) A gridded sea surface salinity data set for the tropical Pacific with sample applications (1950–2008). Deep Sea Res 58:38–48. doi: 10.1016/j.dsr.2010.11.002 CrossRefGoogle Scholar
  22. Dickson RR, Meincke J, Malmberg S, Lee AJ (1988) The “great salinity anomaly” in the northern North Atlantic 1968–1982. Prog Oceanogr 20:103–151CrossRefGoogle Scholar
  23. Durack PJ, Wijffels SE (2010) Fifty-year trends in global ocean salinities and their relationship to broad-scale warming. J Clim 23:4342–4362. doi: 10.1175/2010JCLI3377.1 CrossRefGoogle Scholar
  24. Durack PJ, Wijffels SE, Matear RJ (2012) Ocean salinities reveal strong global water cycle intensification during 1950 to 2000. Science 336:455–458. doi: 10.1126/science.1212222 CrossRefGoogle Scholar
  25. Gille ST (2002) Warming of the Southern Ocean since the 1950s. Science 295(5558):1275–1277. doi: 10.1126/science.1065863 CrossRefGoogle Scholar
  26. Gille ST (2008) Decadal-scale temperature trends in the southern hemisphere ocean. J Clim 21(18):4749–4765. doi: 10.1175/2008JCLI2131.1 CrossRefGoogle Scholar
  27. Gouretski V, Koltermann KP (2007) How much is the ocean really warming? Geophys Res Lett 34(1):L01610. doi: 10.1029/2006GL027834 CrossRefGoogle Scholar
  28. Hasson AEA, 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):179–194. doi: 10.1007/s10236-013-0596-2 CrossRefGoogle Scholar
  29. Held IM, Soden BJ (2006) Robust responses of the hydrological cycle to global warming. J Clim 19:5686–5699. doi: 10.1175/JCLI3990.1 CrossRefGoogle Scholar
  30. Helm KP, Bindoff NL, Church JA (2010) Changes in the global hydrological-cycle inferred from ocean salinity. Geophys Res Lett 37:L18701. doi: 10.1029/2010GL044222 CrossRefGoogle Scholar
  31. Hosoda S, Suga T, Shikama N, Mizuno K (2009) Global surface layer salinity change detected by Argo and its implication for hydrological cycle intensification. J Oceanogr 65:579–586. doi: 10.1007/s10872-009-0049-1 CrossRefGoogle Scholar
  32. Huffman GJ, Adler RF, Bolvin DT, Gu G (2009) Improving the global precipitation record: GPCP version 2.1. Geophys Res Lett 36:L17808. doi: 10.1029/2009GL040000 CrossRefGoogle Scholar
  33. Hurrell JW (1995) Decadal trends in the North Atlantic Oscillation: regional temperatures and precipitation. Science 269:676–679. doi: 10.1126/science.269.5224.676 CrossRefGoogle Scholar
  34. Hurrell JW, Deser C (2010) North Atlantic climate variability: the role of the North Atlantic Oscillation. J Mar Syst 79:231–244. doi: 10.1016/j.jmarsys.2009.11.002 CrossRefGoogle Scholar
  35. Ingleby B, Huddleston M (2007) Quality control of ocean temperature and salinity profiles-historical and real-time data. J Mar Syst 65:158–175. doi: 10.1016/j.jmarsys.2005.11.019 CrossRefGoogle Scholar
  36. John VO, Allan RP, Soden BJ (2009) How robust are observed and simulated precipitation responses to Tropical Ocean warming? Geophys Res Lett 36:L14702CrossRefGoogle Scholar
  37. Kanamitsu M, Ebisuzaki W, Woollen J, Yang S, Hnilo J, Fiorino M, Potter G (2002) NCEP DOE AMIP-II reanalysis (r-2). Bull Am Meteorol Soc 83:1631–1643CrossRefGoogle Scholar
  38. Kavvada A, Ruiz-Barradas A, Nigam S (2013) AMO’s structure and climate footprint in observations and IPCC AR5 climate simulations. Clim Dyn. doi: 10.1007/s00382-013-1712-1 Google Scholar
  39. Kistler R, Kalnay E, Collins W, Saha S, White G, Woollen J, Chelliah M, Ebisuzaki W, Kanamitsu M, Kousky V et al (2001) The NCEP–NCAR 50-year reanalysis: monthly means CD-ROM and documentation Bull. Bull Am Meteorol Soc 82:247–267CrossRefGoogle Scholar
  40. L’Heureux ML, Lee S, Lyon B (2013) Recent multidecadal strengthening of the Walker circulation across the tropical Pacific. Nat Clim Change 3:571–576. doi: 10.1038/NCLIMATE1840 Google Scholar
  41. Large W, Yeager S (2009) The global climatology of an interannually varying air–sea flux dataset. Clim Dyn 33:341–364CrossRefGoogle Scholar
  42. Lau K-M, Wu H-T (2007) Detecting trends in tropical rainfall characteristics, 1979–2003. Int J Climatol 27:979–988. doi: 10.1002/joc.1454 CrossRefGoogle Scholar
  43. Li L, Jiang X, Chahine MT, Olsen ET, Fetzer EJ, Chen L, Yung YL (2011) The recycling rate of atmospheric moisture over the past two decades (1988–2009). Env Res Lett 6:034018. doi: 10.1088/1748-9326/6/3/034018 CrossRefGoogle Scholar
  44. Liu C, Allan RP (2012) Multi-satellite observed responses of precipitation and its extremes to interannual climate variability. J Geophys Res 117:D03101. doi: 10.1029/2011JD016568 Google Scholar
  45. Liu J, Xiao T, Chen L (2011) Intercomparisons of air–sea heat fluxes over the Southern Ocean. J Clim 24(4):1198–1211. doi: 10.1175/2010JCLI3699.1 CrossRefGoogle Scholar
  46. Liu C, Allan RP, Huffman GJ (2012) Co-variation of temperature and precipitation in CMIP5 models and satellite observations. Geophys Res Lett 39:L13803. doi: 10.1029/2012GL052093 Google Scholar
  47. Lozier MS, Stewart NM (2008) On the temporally northward penetration of Mediterranean overflow water and eastward penetration of Labrador Sea Water. J Phys Oceanogr 38:2097–2103CrossRefGoogle Scholar
  48. McCartney MS, Mauritzen C (2001) On the origin of the warm inflow to the Nordic Seas. Prog Oceanogr 51:125–214CrossRefGoogle Scholar
  49. Meehl GA, Stocker TF, Collins WD et al (2007) Global climate projections. In: Solomon S et al (eds) Climate change 2007: the physical science basis, contribution of working group 1 to the fourth assessment report of the intergovernmental panel on climate change. Cambridge University Press, New York, pp 747–845Google Scholar
  50. Merrifield MA (2011) A shift in Western Tropical Pacific sea level trends during the 1990s. J Clim 24:4126–4138. doi: 10.1175/2011JCLI3932.1 CrossRefGoogle Scholar
  51. Pierce DW, Gleckler PJ, Barnett TP, Santer BD, Durack PJ (2012) The fingerprint of human-induced changes in the ocean’s salinity and temperature fields. Geophys Res Lett 39:L21704. doi: 10.1029/2012GL053389 CrossRefGoogle Scholar
  52. Potter R, Lozier S (2004) On the warming and salinification of the Mediterranean outflow waters in the North Atlantic. Geophys Res Lett 31:L01202. doi: 10.1029/2003GL018161 CrossRefGoogle Scholar
  53. Reid JL (1979) On the contribution of the Mediterranean Sea outflow to the Norwegian–Greenland Sea. Deep Sea Res Part A 26:1199–1223CrossRefGoogle Scholar
  54. Richter I, Xie SP (2010) Moisture transport from the Atlantic to the Pacific basin and its response to North Atlantic cooling and global warming. Clim Dyn 35:551–566CrossRefGoogle Scholar
  55. Rixen M et al (2005) The Western Mediterranean deep water: a proxy for climate change. Geophys Res Lett 32:L12608. doi: 10.1029/2005GL022702 CrossRefGoogle Scholar
  56. Rohling EJ, Bryden HL (1992) Man-induced salinity and temperature increases in western Mediterranean water. J Geophys Res 97:11191–11198CrossRefGoogle Scholar
  57. Santer BD, Mears C, Wentz FJ et al (2007) Identification of human-induced changes in atmospheric moisture content. Proc Nat Acad Sci 104(39):15248–15253CrossRefGoogle Scholar
  58. Schanze JJ, Schmitt RW, Yu LL (2010) The global oceanic freshwater cycle: a state-of-the-art quantification. J Mar Res 68:569–595. doi: 10.1357/002224010794657164 CrossRefGoogle Scholar
  59. Schmitt RW (2008) Salinity and the global water cycle. Oceanography 21:12–19. doi: 10.5670/oceanog.2008.63 CrossRefGoogle Scholar
  60. Skliris N, Sofianos S, Lascaratos A (2007) Hydrological changes in the Mediterranean Sea in relation to changes in the freshwater budget: a numerical modelling study. J Mar Syst 65:400–416CrossRefGoogle Scholar
  61. Sohn BJ, Yeh SW, Schmetz J, Song HJ (2013) Observational evidences of Walker circulation change over the last 30 years contrasting with GCM results. Clim Dyn 40:1721–1732. doi: 10.1007/s00382-012-1484-z CrossRefGoogle Scholar
  62. Solomon S, Qin D, Manning M, Marquis M, Averyt KB, Tignor MM, Miller HL Jr, Chen Z (eds) (2007) Climate change 2007: the physical science basis. Cambridge University Press, CambridgeGoogle Scholar
  63. Stott PA, Sutton RT, Smith DM (2008) Detection and attribution of Atlantic salinity changes. Geophys Res Lett 35:L21702. doi: 10.1029/2008GL035874 CrossRefGoogle Scholar
  64. Sutton R, Hodson D (2003) Influence of the ocean on North Atlantic climate variability 1871–1999. J Clim 16:3296–3313. doi: 10.1126/science.1109496 CrossRefGoogle Scholar
  65. Terray L, Corre L, Cravatte S, Delcroix T, Reverdin G, Ribes A (2012) Near-surface salinity as nature’s rain gauge to detect human influence on the tropical water cycle. J Clim 25:958–977CrossRefGoogle Scholar
  66. Tian Y, Peters-Lidard CD, Eylander JN, Joyce RJ, Huffman GJ, Adler RF, Hsu K-L, Turk FJ, Garcia M, Zeng J (2009) Component analysis of errors in satellite-based precipitation estimates. J Geophys Res 114:D24101. doi: 10.1029/2009JD011949 CrossRefGoogle Scholar
  67. Trenberth KE, Smith L (2005) The mass of the atmosphere: a constraint on global analyses. J Clim 18(6):864–875. doi: 10.1175/JCLI-3299.1 CrossRefGoogle Scholar
  68. Trenberth KE, Fasullo J, Smith L (2005) Trends and variability in column-integrated atmospheric water vapor. Clim Dyn 24:741–758. doi: 10.1007/s00382-005-0017-4 CrossRefGoogle Scholar
  69. Trenberth KE, Smith L, Qian T, Dai A, Fasullo J (2007) Estimates of the global water budget and its annual cycle using observational and model data. J Hydrometeorol 8:758–769. doi: 10.1175/JHM600.1 CrossRefGoogle Scholar
  70. Trenberth KE, Fasullo J, Mackaro J (2011) Atmospheric moisture transports from ocean to land and global energy flows in reanalyses. J Clim 24(18):4907–4924. doi: 10.1175/2011JCLI4171.1 CrossRefGoogle Scholar
  71. Tzortzi E, Josey SA, Srokosz M, Gommenginger C (2013) Tropical Atlantic salinity variability: new insights from SMOS. Geophys Res Lett 40:2143–2147. doi: 10.1002/grl.50225 CrossRefGoogle Scholar
  72. Vinogradova NT, Ponte RM (2013) Clarifying the link between surface salinity and freshwater fluxes on monthly to inter-annual timescales. J Geophys Res 118:3190–3201. doi: 10.1002/jgrc.20200 CrossRefGoogle Scholar
  73. Wadley MR, Bigg GR (2006) Are “great salinity anomalies” advective? J Clim 19:1080–1088. doi: 10.1175/JCLI3647.1 CrossRefGoogle Scholar
  74. Wentz FJ, Ricciardulli L, Hilburn K, Mears C (2007) How much more rain will global warming bring? Science 317(5835):233–235. doi: 10.1126/science.1140746 CrossRefGoogle Scholar
  75. Wijffels S (2001) Ocean transport of fresh water. In: Siedler G, Church J, Gould J (eds) Ocean circulation and climate. Academic Press, New York, pp 475–488Google Scholar
  76. Willett KW, Gillett NP, Jones PD, Thorne PW (2007) Attribution of observed humidity changes to human influence. Nature 449:710–712CrossRefGoogle Scholar
  77. Xie P, Arkin PA (1996) Global precipitation: a 17-year monthly analysis based on gauge observations, satellite estimates, and numerical model outputs. Bull Am Meteorol Soc 78:2539–2558CrossRefGoogle Scholar
  78. Yin X, Gruber A, Arkin P (2004) Comparison of the GPCP and CMAP Merged Gauge–Satellite monthly precipitation products for the period 1979–2001. J Hydrometeorol 5:1207–1222. doi: 10.1175/JHM-392.1 CrossRefGoogle Scholar
  79. Yu L (2011) A global relationship between the ocean water cycle and near-surface salinity. J Geophys Res 116:C10025. doi: 10.1029/2010JC006937 CrossRefGoogle Scholar
  80. Yu L, Weller RA (2007) Objectively analyzed air–sea flux fields for the global ice-free oceans (1981–2005). Bull Am Meteorol Soc 88:527–539CrossRefGoogle Scholar
  81. Yu L, Jin X, Weller RA (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. OAFlux project technical report (OA2008–01), Woods Hole Oceanographic InstitutionGoogle Scholar
  82. Zhang et al (2007) Detection of human influence on twentieth-century precipitation trends. Nature 448:461–465. doi: 10.1038/nature06025 CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Nikolaos Skliris
    • 1
  • Robert Marsh
    • 1
  • Simon A. Josey
    • 2
  • Simon A. Good
    • 3
  • Chunlei Liu
    • 4
  • Richard P. Allan
    • 4
  1. 1.Ocean and Earth Science, National Oceanography Centre, SouthamptonUniversity of SouthamptonSouthamptonUK
  2. 2.National Oceanography CentreSouthamptonUK
  3. 3.Met Office Hadley CentreExeterUK
  4. 4.National Centre for Atmospheric ScienceUniversity of ReadingReadingUK

Personalised recommendations