Abstract
Based on Argo sea surface salinity (SSS) and the related precipitation (P), evaporation (E), and sea surface height data sets, the climatological annual mean and low-frequency variability in SSS in the global ocean and their relationship with ocean circulation and climate change were analyzed. Meanwhile, together with previous studies, a brief retrospect and prospect of seawater salinity were given in this work. Freshwater flux (E-P) dominated the mean pattern of SSS, while the dynamics of ocean circulation modulated the spatial structure and low-frequency variability in SSS in most regions. Under global warming, the trend in SSS indicated the intensification of the global hydrological cycle, and featured a decreasing trend at low and high latitudes and an increasing trend in subtropical regions. In the most recent two decades, global warming has slowed down, which is called the “global warming hiatus”. The trend in SSS during this phase, which was different to that under global warming, mainly indicated the response of the ocean surface to the decadal and multi-decadal variability in the climate system, referring to the intensification of the Walker Circulation. The significant contrast of SSS trends between the western Pacific and the southeastern Indian Ocean suggested the importance of oceanic dynamics in the cross-basin interaction in recent decades. Ocean Rossby waves and the Indonesian Throughflow contributed to the freshening trend in SSS in the southeastern Indian Ocean, while the increasing trend in the southeastern Pacific and the decreasing trend in the northern Atlantic implied a long-term linear trend under global warming. In the future, higher resolution SSS data observed by satellites, together with Argo observations, will help to extend our knowledge on the dynamics of mesoscale eddies, regional oceanography, and climate change.
Similar content being viewed by others
References
Adler R F, Huffman G J, Chang A, Ferraro R, Xie P P, Janowiak J, Rudolf B, Schneider U, Curtis S, Bolvin D, Gruber A, Susskind J, Arkin P, Nelkin E. 2003. The version-2 global precipitation climatology project (GPCP) monthly precipitation analysis (1979–present). J Hydrometeorol, 4: 1147–1167
Atlas R, Hoffman R N, Ardizzone J, Leidner S M, Jusem J C, Smith D K, Gombos D. 2011. A cross-calibrated, multiplatform ocean surface wind velocity product for meteorological and oceanographic applications. Bull Amer Meteorol Soc, 92: 157–174
Boyer T P, Levitus S, Antonov J I, Locarnini R A, Garcia H E. 2005. Linear trends in salinity for the World Ocean, 1955–1998. Geophys Res Lett, 32: L01604
Bo Y Y, Yeh S W, Noh Y, Moon B K, Park Y G. 2008. Sea surface salinity variability and its relation to El Niño in a CGCM. Asia-Pac J Atmos Sci, 44: 173–189
Chakraborty A, Sharma R, Kumar R, Basu S. 2014. A SEEK filter assimilation of sea surface salinity from Aquarius in an OGCM: Implication for surface dynamics and thermohaline structure. J Geophys Res-Oceans, 119: 4777–4796
Chen X Y, Tung K K. 2014. Varying planetary heat sink led to global-warming slowdown and acceleration. Science, 345: 897–903
Collins M, An S I, Cai W, Ganachaud A, Guilyardi E, Jin F F, Jochum M, Lengaigne M, Power S, Timmermann A, Vecchi G, Wittenberg A. 2010. The impact of global warming on the tropical Pacific Ocean and El Niño. Nat Geosci, 3: 391–397
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
Dee D P, Uppala S M, Simmons A J, Berrisford P, Poli P, Kobayashi S, Andrae U, Balmaseda M A, Balsamo G, Bauer P, Bechtold P, Beljaars A C M, van de Berg L, Bidlot J, Bormann N, Delsol C, Dragani R, Fuentes M, Geer A J, Haimberger L, Healy S B, Hersbach H, Hólm E V, Isaksen L, Kållberg P, Köhler M, Matricardi M, McNally A P, Monge-Sanz B M, Morcrette J J, Park B K, Peubey C, de Rosnay P, Tavolato C, Thépaut J N, Vitart F. 2011. The ERA-Interim reanalysis: Configuration and performance of the data assimilation system. Q J R Meteorol Soc, 137: 553–597
Delcroix T, Alory G, Cravatte S, Corrège T, McPhaden M J. 2011. A gridded sea surface salinity data set for the tropical Pacific with sample applications (1950–2008). Deep-Sea Res Part I-Oceanogr Res Pap, 58: 38–48
Delcroix T, Cravatte S, McPhaden M J. 2007. Decadal variations and trends in tropical Pacific sea surface salinity since 1970. J Geophys Res, 112: C03012
Delcroix T, Hénin C. 1991. Seasonal and interannual variations of sea surface salinity in the tropical Pacific Ocean. J Geophys Res, 96: 22135–22150
Du Y, Zhang Y H. 2015. Satellite and Argo observed surface salinity variations in the tropical Indian Ocean and their association with the Indian Ocean dipole mode. J Clim, 28: 695–713
Du Y, Zhang Y H, Feng M, Wang T Y, Zhang N, Wijffels S. 2015. Decadal trends of the upper ocean salinity in the tropical Indo-Pacific since mid-1990s. Sci Rep, 5: 16050
Durack P. 2015. Ocean salinity and the global water cycle. Oceanography, 28: 20–31
Durack P J, Wijffels S E, Matear R J. 2012. Ocean salinities reveal strong global water cycle intensification during 1950 to 2000. Science, 336: 455–458
Durand F, Alory G, Dussin R, Reul N. 2013. Smos reveals the signature of Indian Ocean dipole events. Ocean Dyn, 63: 1203–1212
England M H, McGregor S, Spence P, Meehl G A, Timmermann A, Cai W, Gupta A S, McPhaden M J, Purich A, Santoso A. 2014. Recent intensification of wind-driven circulation in the Pacific and the ongoing warming hiatus. Nat Clim Change, 4: 222–227
Feng M, McPhaden M J, Lee T. 2010. Decadal variability of the Pacific subtropical cells and their influence on the southeast Indian Ocean. Geophys Res Lett, 37: L09606
Gao S, Qu T, Nie X. 2014. Mixed layer salinity budget in the tropical Pacific Ocean estimated by a global GCM. J Geophys Res-Oceans, 119: 8255–8270
Good S A, Martin M J, Rayner N A. 2013. EN4: Quality controlled ocean temperature and salinity profiles and monthly objective analyses with uncertainty estimates. J Geophys Res-Oceans, 118: 6704–6716
Gordon A, Giulivi C. 2008. Sea surface salinity trends over fifty years within the subtropical North Atlantic. Oceanography, 21: 20–29
Gordon A L, Susanto R D, Vranes K. 2003. Cool Indonesian Throughflow as a consequence of restricted surface layer flow. Nature, 425: 824–828
Gordon A L, Susanto R D, Ffield A, Huber B A, Pranowo W, Wirasantosa S. 2008. Makassar Strait throughflow, 2004 to 2006. Geophys Res Lett, 35: L24605
Grunseich G, Subrahmanyam B, Wang B. 2013. The Madden-Julian oscillation detected in Aquarius salinity observations. Geophys Res Lett, 40: 5461–5466
Guerrero R A, Piola A R, Fenco H, Matano R P, Combes V, Chao Y, James C, Palma E D, Saraceno M, Strub P T. 2014. The salinity signature of the cross-shelf exchanges in the Southwestern Atlantic Ocean: Satellite observations. J Geophys Res-Oceans, 119: 7794–7810
Hartmann J, West A J, Renforth P, Köhler P, De La Rocha C L, Wolf-Gladrow D A, Dürr H H, Scheffran J. 2013. Enhanced chemical weathering as a geoengineering strategy to reduce atmospheric carbon dioxide, supply nutrients, and mitigate ocean acidification. Rev Geophys, 51: 113–149
Held I M, Soden B J. 2006. Robust responses of the hydrological cycle to global warming. J Clim, 19: 5686–5699
Hosoda S, Ohira T, Nakamura T. 2008. A monthly mean dataset of global oceanic temperature and salinity derived from Argo float observations. JAMSTEC-R, 8: 47–59
Huffman G J, Adler R F, Bolvin D T, Gu G. 2009. Improving the global precipitation record: GPCP version 2.1. Geophys Res Lett, 36: L17808
Hu S, Sprintall J. 2017. Observed strengthening of interbasin exchange via the Indonesian Seas due to rainfall intensification. Geophys Res Lett, 44: 1448–1456
IPCC. 2014. Climate Change 2014. In: Edenhofer O, Pichs-Madruga R, Sokona Y, Farahani E, Kadner S, Seyboth K, Adler A, Baum I, Brunner S, Eickemeier P, Kriemann B, Savolainen J, Schlömer S, von Stechow C, Zwickel T, Minx J C, eds. Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge: Cambridge University Press
Jackson T J, Hsu A Y, Van de Griend A, Eagleman J R. 2004. Skylab Lband microwave radiometer observations of soil moisture revisited. Int J Remote Sens, 25: 2585–2606
Kim S, Lee J H, de Matthaeis P, Yueh S, Hong C S, Lee J H, Lagerloef G. 2014. Sea surface salinity variability in the East China Sea observed by the Aquarius instrument. J Geophys Res-Oceans, 119: 7016–7028
Köhl A, Sena Martins M, Stammer D. 2014. Impact of assimilating surface salinity from SMOS on ocean circulation estimates. J Geophys Res-Oceans, 119: 5449–5464
Kosaka Y, Xie S P. 2013. Recent global-warming hiatus tied to equatorial Pacific surface cooling. Nature, 501: 403–407
Lagerloef G, Wentz F, Yueh S, Kao H Y, Johnson G C, Lyman J M. 2012. Aquarius satellitemission provides new, detailed view of sea surface salinity. Bull Amer Meteorol Soc, 93: S70–S71
Li J, Liang C, Tang Y, Dong C, Chen D, Liu X, Jin W. 2016. A new dipole index of the salinity anomalies of the tropical Indian Ocean. Sci Rep, 6: 24260
Li M, Gordon A L, Wei J, Gruenburg L K, Jiang G. 2018. Multi-decadal timeseries of the Indonesian Throughflow. Dyn Atmos Oceans, 81: 84–95
Li Y, Han W, Lee T. 2015. Intraseasonal sea surface salinity variability in the equatorial Indo-Pacific Ocean induced by Madden-Julian oscillations. J Geophys Res-Oceans, 120: 2233–2258
Li Y, Han W, Wang W, Ravichandran M, Lee T, Shinoda T. 2017. Bay of Bengal salinity stratification and Indian summer monsoon intraseasonal oscillation: 2. Impact on SST and convection. J Geophys Res-Oceans, 122: 4312–4328
Lukas R, Santiago-Mandujano F. 2008. Interannual to interdecadal salinity variations observed near hawaii: Local and remote forcing by surface freshwater fluxes. Oceanography, 21: 46–55
Maes C, Picaut J, Belamari S. 2002. Salinity barrier layer and onset of El Niño in a Pacific coupled model. Geophys Res Lett, 29: 59-1–59-4
Masson S, Delecluse P, Boulanger J P, Menkes C. 2002. A model study of the seasonal variability and formation mechanisms of the barrier layer in the eastern equatorial Indian Ocean. J Geophys Res, 107: SRF 18-1–SRF 18-20
Masson S, Menkes C, Delecluse P, Boulanger J P. 2003. Impacts of salinity on the eastern Indian Ocean during the termination of the fall Wyrtki Jet. J Geophys Res, 108: 3067
Masson S, Boulanger J P, 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
Meehl G A, Arblaster J M, Fasullo J T, Hu A, Trenberth K E. 2011. Model-based evidence of deep-ocean heat uptake during surface-temperature hiatus periods. Nat Clim Change, 1: 360–364
Menezes V V, Vianna M L, Phillips H E. 2014. Aquarius sea surface salinity in the South Indian Ocean: Revealing annual-period planetary waves. J Geophys Res-Oceans, 119: 3883–3908
Merrifield M A. 2011. A shift in western tropical Pacific sea level trends during the 1990s. J Clim, 24: 4126–4138
Mignot J, Frankignoul C. 2010. Local and remote impacts of a tropical Atlantic salinity anomaly. Clim Dyn, 35: 1133–1147
Nyadjro E S, Subrahmanyam B. 2014. SMOS mission reveals the salinity structure of the Indian Ocean dipole. IEEE Geosci Remote Sens Lett, 11: 1564–1568
Qiu B, Lukas R. 1996. Seasonal and interannual variability of the North Equatorial Current, the Mindanao Current, and the Kuroshio along the Pacific western boundary. J Geophys Res, 101: 12315–12330
Qiu Y, Cai W, Li L, Guo X. 2012. Argo profiles variability of barrier layer in the tropical Indian Ocean and its relationship with the Indian Ocean Dipole. Geophys Res Lett, 39: L08605
Qu T, Gao S, Fukumori I. 2011. What governs the North Atlantic salinity maximum in a global GCM? Geophys Res Lett, 38: L07602
Qu T, Gao S, Fukumori I. 2013. Formation of salinity maximum water and its contribution to the overturning circulation in the North Atlantic as revealed by a global general circulation model. J Geophys Res-Oceans, 118: 1982–1994
Qu T, Gao S. 2017. Resurfacing of South Pacific tropical water in the Equatorial Pacific and its variability associated with ENSO. J Phys Oceanogr, 47: 1095–1106
Qu T, Song Y T, Maes C. 2014. Sea surface salinity and barrier layer variability in the equatorial Pacific as seen from Aquarius and Argo. J Geophys Res-Oceans, 119: 15–29
Qu T, Yu J Y. 2014. ENSO indices from sea surface salinity observed by Aquarius and Argo. J Oceanogr, 70: 367–375
Schmitt R W. 2008. Salinity and the global water cycle. Oceanography, 21: 12–19
Skliris N, Marsh R, Josey S A, Good S A, Liu C, Allan R P. 2014. Salinity changes in the world ocean since 1950 in relation to changing surface freshwater fluxes. Clim Dyn, 43: 709–736
Tang Z. 2013. Study on Foreign Ocean Salinity and Soil Moisture Detector Satellite. Spacecraft Eng, 22: 83–89
Thompson B, Gnanaseelan C, Salvekar P S. 2006. Variability in the Indian Ocean circulation and salinity and its impact on SST anomalies during dipole events. J Mar Res, 64: 853–880
Thorpe R B, Gregory J M, Johns T C, Wood R A, Mitchell J F B. 2001. Mechanisms determining the Atlantic thermohaline circulation response to greenhouse gas forcing in a non-flux-adjusted coupled climate model. J Clim, 14: 3102–3116
Trenberth K E, 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
Vecchi G A, Soden B J. 2007. Global warming and the weakening of the tropical circulation. J Clim, 20: 4316–4340
Vellinga M, Wu P. 2004. Low-latitude freshwater influence on centennial variability of the Atlantic thermohaline circulation. J Clim, 17: 4498–4511
Wang C, Dong S, Munoz E. 2010. Seawater density variations in the North Atlantic and the Atlantic meridional overturning circulation. Clim Dyn, 34: 953–968
Wang T Y, Du Y, Zhuang W, Wang J B. 2015. Connection of sea level variability between the tropical western Pacific and the southern Indian Ocean during recent two decades. Sci China Earth Sci, 58: 1387–1396
Wijffels S, Meyers G. 2004. An intersection of oceanic waveguides: Variability in the Indonesian Throughflow region. J Phys Oceanogr, 34: 1232–1253
Xie P, Boyer T, Bayler E, Xue Y, Byrne D, Reagan J, Locarnini R, Sun F, Joyce R, Kumar A. 2014. An in situ-satellite blended analysis of global sea surface salinity. J Geophys Res-Oceans, 119: 6140–6160
Xie S P, Kosaka Y, Du Y, Hu K, Chowdary J S, Huang G. 2016. Indowestern Pacific ocean capacitor and coherent climate anomalies in post-ENSO summer: A review. Adv Atmos Sci, 33: 411–432
Yashayaev I, Clarke A. 2008. Evolution of north Atlantic water masses inferred from Labrador Sea salinity series. Oceanography, 21: 30–45
Yin X, Boutin J, Reverdin G, Lee T, Arnault S, Martin N. 2014. SMOSSea surface salinity signals of tropical instability waves. J Geophys Res-Oceans, 119: 7811–7826
Yin X, Zhang Q, Wang R, Zhang H. 2016. Development Status and Trends of Sea Surface Salt Satellite. Spacecraft Eng, 25: 119–123
Yu L. 2011. A global relationship between the ocean water cycle and near-surface salinity. J Geophys Res, 116: C10025
Yu L. 2014. Coherent evidence from Aquarius and Argo for the existence of a shallow low-salinity convergence zone beneath the Pacific ITCZ. J Geophys Res-Oceans, 119: 7625–7644
Yu L, Weller R A. 2007. Objectively analyzed air-sea heat fluxes for the global ice-free oceans (1981–2005). Bull Amer Meteorol Soc, 88: 527–540
Zeng L, Timothy Liu W, Xue H, Xiu P, Wang D. 2014. Freshening in the South China Sea during 2012 revealed by Aquarius and in situ data. J Geophys Res-Oceans, 119: 8296–8314
Zhang L, Wu L. 2012. Can oceanic freshwater flux amplify global warming? J Clim, 25: 3417–3430
Zhang R H, Busalacchi A J. 2009. Freshwater flux (FWF)-induced oceanic feedback in a hybrid coupled model of the tropical pacific. J Clim, 22: 853–879
Zhang R H, Zheng F, Zhu J, Pei Y, Zheng Q, Wang Z. 2012. Modulation of El Niño-southern oscillation by freshwater flux and salinity variability in the tropical pacific. Adv Atmos Sci, 29: 647–660
Zhang R H, Gao C, Kang X, Zhi H, Wang Z, Feng L. 2015. ENSO modulations due to interannual variability of freshwater forcing and ocean biology-induced heating in the tropical Pacific. Sci Rep, 5: 18506
Zhang Y H, Du Y, Feng M. 2018. Multiple time scale variability of the sea surface salinity dipole mode in the tropical Indian Ocean. J Clim, 31: 283–296
Zhang Y H, Du Y, Zheng S J, Yang Y L, Cheng X H. 2013. Impact of Indian Ocean dipole on the salinity budget in the equatorial Indian Ocean. J Geophys Res-Oceans, 118: 4911–4923
Zhang Y H, Du Y, Qu T. 2016. A sea surface salinity dipole mode in the tropical Indian Ocean. Clim Dyn, 47: 2573–2585
Zheng F, Zhang R H. 2012. Effects of interannual salinity variability and freshwater flux forcing on the development of the 2007/08 La Niña event diagnosed from Argo and satellite data. Dyn Atmos Oceans, 57: 45–57
Zheng F, Zhang R H. 2015. Interannually varying salinity effects on ENSO in the tropical pacific: A diagnostic analysis from Argo. Ocean Dyn, 65: 691–705
Zhu J, Huang B, Zhang R H, Hu Z Z, Kumar A, Balmaseda M A, Marx L, Kinter III J L. 2014. Salinity anomaly as a trigger for ENSO events. Sci Rep, 4: 6821
Acknowledgements
We thank Water Cycle Observation Mission (WCOM) group and PhD Student Qiwei SUN for their helps. Argo salinity data is available at (http://www.argo.ucsd.edu), EN4salinity data is obtained from (http://hadobs.metoffice.com/en4/index.html), CCMP wind data is provided by RSS (http://www.remss.com), sea surface height data is provided by AVISO (https://www.aviso.altimetry.fr), GPCP precipitation data is obtained from NASA/GSFC, evaporation data is provided by OAFlux (http://oaflux.whoi.edu), and ERA Interim sea level pressure data is provided by ECMWF (http://apps.ecmwf.int/datasets). This work was supported by the Chinese Academy of Sciences (Grant No. XDA19060501), the State Oceanic Administration of China (Grant No. GASI-IPOV AI-02), and the National Natural Science Foundation of China (Grant Nos. 41525019, 41506019 & 41830538).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Du, Y., Zhang, Y. & Shi, J. Relationship between sea surface salinity and ocean circulation and climate change. Sci. China Earth Sci. 62, 771–782 (2019). https://doi.org/10.1007/s11430-018-9276-6
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11430-018-9276-6