Abstract
The tropical Indian Ocean circulation system includes the equatorial and near-equatorial circulations, the marginal sea circulation, and eddies. The dynamic processes of these circulation systems show significant multi-scale variability associated with the Indian Monsoon and the Indian Ocean dipole. This paper summarizes the research progress over recent years on the tropical Indian Ocean circulation system based on the large-scale hydrological observations and numerical simulations by the South China Sea Institute of Oceanology (SCSIO), Chinese Academy of Sciences. Results show that: (1) the wind-driven Kelvin and Rossby waves and eastern boundary-reflected Rossby waves regulate the formation and evolution of the Equatorial Undercurrent and the Equatorial Intermediate Current; (2) the equatorial wind-driven dynamics are the main factor controlling the inter-annual variability of the thermocline in the eastern Indian Ocean upwelling; (3) the equatorial waves transport large amounts of energy into the Bay of Bengal in forms of coastal Kelvin and reflected free Rossby waves. Several unresolved issues within the tropical Indian Ocean are discussed: (i) the potential effects of the momentum balance and the basin resonance on the variability of the equatorial circulation system, and (ii) the potential contribution of wind-driven dynamics to the life cycle of the eastern Indian Ocean upwelling. This paper also briefly introduces the international Indian Ocean investigation project of the SCSIO, which will advance the study of the multi-scale variability of the tropical Indian Ocean circulation system, and provide a theoretical and data basis to support marine environmental security for the countries around the Maritime Silk Road.
Similar content being viewed by others
References
Anderson D L T, Carrington D J. 1993. Modeling interannual variability in the Indian Ocean using momentum fluxes from the operational weather analyses of the United Kingdom Meteorological Office and European Centre for Medium Range Weather Forecasts. J Geophys Res, 98: 12483–12499
Arief D, Murray S P. 1996. Low-frequency fluctuations in the Indonesian throughflow through Lombok Strait. J Geophys Res, 101: 12455–12464
Babu M T, Sarma Y V B, Murty V S N, Vethamony P. 2003. On the circulation in the Bay of Bengal during Northern spring inter-monsoon (March–April 1987). Deep-Sea Res Part II-Top Stud Oceanogr, 50: 855–865
Balmaseda M A, Trenberth K E, Källén E. 2013. Distinctive climate signals in reanalysis of global ocean heat content. Geophys Res Lett, 40: 1754–1759
Brandt P, Claus M, Greatbatch R J, Kopte R, Toole J M, Johns W E, Böning C W. 2016. Annual and semiannual cycle of equatorial Atlantic circulation associated with Basin-Mode resonance. J Phys Oceanogr, 46: 3011–3029
Bograd S J, Schroeder I, Sarkar N, Qiu X, Sydeman W J, Schwing F B. 2009. Phenology of coastal upwelling in the California Current. Geophys Res Lett, 36: L01602
Chen G X, Wang D X, Hou Y J. 2012. The features and interannual variability mechanism of mesoscale eddies in the Bay of Bengal. Cont Shelf Res, 47: 178–185
Chen G X, Han W Q, Li Y L, Wang D, McPhaden M J. 2015a. Seasonal-tointerannual time-scale dynamics of the equatorial undercurrent in the Indian Ocean. J Phys Oceanogr, 45: 1532–1553
Chen G X, Han W, Li Y, Wang D, Shinoda T. 2015b. Intraseasonal variability of upwelling in the equatorial Eastern Indian Ocean. J Geophys Res-Oceans, 120: 7598–7615
Chen G X, Han W, Li Y, Wang D. 2016a. Interannual variability of equatorial Eastern Indian Ocean upwelling: Local versus remote forcing. J Phys Oceanogr, 46: 789–807
Chen G X, Han W, Shu Y, Li Y, Wang D, Xie Q. 2016b. The role of Equatorial Undercurrent in sustaining the Eastern Indian Ocean upwelling. Geophys Res Lett, 43: 6444–6451
Chen G X, Han W, Li Y, McPhaden M J, Chen J, Wang W, Wang D. 2017. Strong intraseasonal variability of meridional currents near 5°N in the Eastern Indian Ocean: Characteristics and causes. J Phys Oceanogr, 47: 979–998
Cheng X H, McCreary J P, Qiu B, Qi Y Q, Du Y. 2017. Intraseasonal-tosemiannual variability of sea-surface height in the eastern equatorial Indian Ocean and southern Bay of Bengal. J Geophys Res-Oceans, 122: 4051–4067
Clarke A J, Liu X. 1993. Observations and dynamics of semiannual and annual sea levels near the Eastern Equatorial Indian Ocean boundary. J Phys Oceanogr, 23: 386–399
Delcroix T, Henin C. 1988. Observations of the equatorial intermediate current in the Western Pacific Ocean (165°E). J Phys Oceanogr, 18: 363–366
Duan Y, Liu L, Han G, Liu H, Yu W, Yang G, Wang H, Wang H, Liu Y, Zahid Y, Waheed H. 2016. Anomalous behaviors of Wyrtki Jets in the equatorial Indian Ocean during 2013. Sci Rep, 6: 29688
Eriksen C C. 1981. Deep currents and their interpretation as equatorial waves in the Western Pacific Ocean. J Phys Oceanogr, 11: 48–70
Fischer J, Schott F A. 1997. Seasonal transport variability of the deep western boundary current in the equatorial Atlantic. J Geophys Res, 102: 27751–27769
Firing E. 1987. Deep zonal currents in the central equatorial Pacific. J Mar Res, 45: 791–812
Gill A E. 1982. Atmosphere-Ocean Dynamics. Orlando: Academic
Godfrey J S, Hu R J, Schiller A, Fiedler R. 2007. Explorations of the annual mean heat budget of the tropical Indian Ocean. Part I: Studies with an idealized model. J Clim, 20: 3210–3228
Gouriou Y, Delcroix T, Eldin G. 2006. Upper and intermediate circulation in the western equatorial Pacific Ocean in October 1999 and April 2000. Geophys Res Lett, 33: L10603
Han W Q, McCreary Jr J P, Anderson D L T, Mariano A J. 1999. Dynamics of the eastern surface jets in the equatorial Indian Ocean. J Phys Oceanogr, 29: 2191–2209
Han W, Webster P, Lukas R, Hacker P, Hu A. 2004. Impact of atmospheric intraseasonal variability in the Indian Ocean: Low-frequency rectification in equatorial surface current and transport. J Phys Oceanogr, 34: 1350–1372
Han W Q, McCreary J P, Masumoto Y, Vialard J, Duncan B. 2011. Basin resonances in the equatorial Indian Ocean. J Phys Oceanogr, 41: 1252–1270
Hood R R, Bange H W, Beal L, Beckley L E, Burkill P, Cowie G L, D’Adamo N, Ganssen G, Hendon H, Hermes J, Honda M, McPhaden M, Roberts M, Singh S, Urban E, Yu W. 2015. The Second International Indian Ocean Expedition (IIOE-2): A basin-wide research program-Science Plan (2015–2020). Delaware: SCOR Newark. 101
Iskandar I, Masumoto Y, Mizuno K. 2009. Subsurface equatorial zonal current in the eastern Indian Ocean. J Geophys Res, 114: C06005
Kessler W S, McCreary J P. 1993. The annual wind-driven rossby wave in the subthermocline equatorial Pacific. J Phys Oceanogr, 23: 1192–1207
Knox R A. 1976. On a long series of measurements of Indian Ocean equatorial currents near Addu Atoll. Deep Sea Res Oceanogr Abstr, 23: 211–IN1
Krishnan R, Swapna P. 2009. Significant influence of the boreal summer monsoon flow on the Indian Ocean response during dipole events. J Clim, 22: 5611–5634
Kuswardani. 2012. The development of a wave-tide-circulation coupled model and its upwelling simulation application in the Indonesian Sea. Dissertation for Doctoral Degree. Qingdao: Ocean University of China
Li Y, Han W, Shinoda T, Wang C, Ravichandran M, Wang J W. 2014. Revisiting the wintertime intraseasonal SST variability in the tropical south Indian Ocean: Impact of the Ocean interannual variation. J Phys Oceanogr, 44: 1886–1907
Lukas R, Firing E. 1985. The annual rossby wave in the central equatorial Pacific Ocean. J Phys Oceanogr, 15: 55–67
Luyten J R, Roemmich D H. 1982. Equatorial currents at semi-annual period in the Indian Ocean. J Phys Oceanogr, 12: 406–413
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
McCreary J P. 1980. Modeling wind-driven ocean circulation. Hawaii Institute of Geophysics Tech. HIG-80-3, 64
McCreary J P. 1981. A linear stratified ocean model of the coastal undercurrent. Philos Trans R Soc A-Math Phys Eng Sci, 302: 385–413
McPhaden M J, Meyers G, Ando K, Masumoto Y, Murty V S N, 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 Amer Meteorol Soc, 90: 459–480
McPhaden M J, Wang Y, Ravichandran M. 2015. Volume transports of the Wyrtki jets and their relationship to the Indian Ocean Dipole. J Geophys Res-Oceans, 120: 5302–5317
Nagura M, McPhaden M J. 2016. Zonal propagation of near-surface zonal currents in relation to surface wind forcing in the equatorial Indian Ocean. J Phys Oceanogr, 46: 3623–3638
O’Brien J J, Hurlburt H E. 1974. Equatorial jet in the Indian Ocean: Theory. Science, 184: 1075–1077
Ogata T, Xie S P. 2011. Semiannual cycle in zonal wind over the equatorial Indian Ocean. J Clim, 24: 6471–6485
Philander S G H. 1978. Forced oceanic waves. Rev Geophys, 16: 15
Philander S G H, Chao Y. 1991. On the contrast between the seasonal cycles of the equatorial Atlantic and Pacific Oceans. J Phys Oceanogr, 21: 1399–1406
Reppin J, Schott F A, Fischer J, Quadfasel D. 1999. Equatorial currents and transports in the upper central Indian Ocean: Annual cycle and interannual variability. J Geophys Res, 104: 15495–15514
Saji N H, Goswami B N, Vinayachandran P N, Yamagata T. 1999. A dipole mode in the tropical Indian Ocean. Nature, 401: 360–363
Sanilkumar K V, Kuruvilla T V, Jogendranath D, Rao R R. 1997. Observations of the Western Boundary Current of the Bay of Bengal from a hydrographic survey during March 1993. Deep-Sea Res Part IOceanogr Res Pap, 44: 135–145
Schott F, Fischer J, Garternicht U, Quadfasel D. 1997. Summer monsoon response of the Northern Somali Current, 1995. Geophys Res Lett, 24: 2565–2568
Schott F A, McCreary Jr J P. 2001. The monsoon circulation of the Indian Ocean. Prog Oceanogr, 51: 1–123
Schott F A, Xie S P, McCreary Jr. J P. 2009. Indian Ocean circulation and climate variability. Rev Geophys, 47: RG1002
Shankar D, McCreary J P, Han W, Shetye S R. 1996. Dynamics of the East India Coastal Current: 1. Analytic solutions forced by interior Ekman pumping and local alongshore winds. J Geophys Res, 101: 13975–13991
Shu Y Q, Xue H J, Wang D X, Chai F, Xie Q, Yao J, Xiao J. 2014. Meridional overturning circulation in the South China Sea envisioned from the high-resolution global reanalysis data GLBa0.08. J Geophys Res-Oceans, 119: 3012–3028
Sprintall J, Gordon A L, Murtugudde R, Susanto R D. 2000. A semiannual Indian Ocean forced Kelvin wave observed in the Indonesian seas in May 1997. J Geophys Res, 105: 17217–17230
Susanto R D, Gordon A L, Zheng Q. 2001. Upwelling along the coasts of Java and Sumatra and its relation to ENSO. Geophys Res Lett, 28: 1599–1602
Swallow J. 1967. The equatorial undercurrent in the western Indian Ocean in 1964. Stud Trop Oceanogr, 5: 15–36
Swapna P, Krishnan R. 2008. Equatorial undercurrents associated with Indian Ocean Dipole events during contrasting summer monsoons. Geophys Res Lett, 35: L14S04
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
Valsala V, Maksyutov S, Murtugudde R. 2010. Possible interannual to interdecadal variabilities of the Indonesian throughflow water pathways in the Indian Ocean. J Geophys Res, 115: C10016
Wang D X, Wu G X, Xu J J. 1999. Decadal ocean variability and its dynamical interpretation in tropical Indian Ocean (in Chinese). Chin Sci Bull, 44: 1226–1232
Wang J, Yuan D. 2015. Roles of western and eastern boundary reflections in the interannual sea level variations during negative Indian Ocean dipole events. J Phys Oceanogr, 45: 1804–1821
Webster P J, Moore A M, Loschnigg J P, Leben R R. 1999. Coupled oceanatmosphere dynamics in the Indian Ocean during 1997–98. Nature, 401: 356–360
Wei F Y. 2002. Climate Statistical Diagnosis and Prediction Technology. Beijing: Meteorological Press. 343
Wyrtki K. 1973. An equatorial jet in the Indian Ocean. Science, 181: 262–264
Yu L, O’Brien J J, Yang J. 1991. On the remote forcing of the circulation in the Bay of Bengal. J Geophys Res, 96: 20449
Yuan D L, Han W Q. 2006. Roles of equatorial waves and western boundary reflection in the seasonal circulation of the equatorial Indian Ocean. J Phys Oceanogr, 36: 930–944
Acknowledgements
This work was supported by the National Key Research and Development Program of China (Grant No. 2017YFC 1405100), the National Natural Science Foundation of China (Grant Nos. 41521005, 41476011, 41706027, 41676013), the Natural Science Foundation of Guangdong (Grant No. 2016A030310015), the Open Fund of the Key Laboratory of Ocean Circulation and Waves, Chinese Academy of Sciences (Grant No. KLOCW1604), the Open Fund of the State Key Laboratory of Tropical Oceanography (Grant No. LTOZZ1702), the MEL Visiting Fellowship (Grant No. MELRS1640) and the Guangzhou Science and Technology Foundation (Grant No. 201804010133).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Huang, K., Wang, D., Wang, W. et al. Multi-scale variability of the tropical Indian Ocean circulation system revealed by recent observations. Sci. China Earth Sci. 61, 668–680 (2018). https://doi.org/10.1007/s11430-017-9179-x
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11430-017-9179-x