Evidence for the existence of Persian Gulf Water and Red Sea Water in the Bay of Bengal


The high-salinity water masses that originate in the North Indian Ocean are Arabian Sea High-Salinity Water (ASHSW), Persian Gulf Water (PGW), and Red Sea Water (RSW). Among them, only ASHSW has been shown to exist in the Bay of Bengal. We use CTD data from recent cruises to show that PGW and RSW also exist in the bay. The presence of RSW is marked by a deviation of the salinity vertical profile from a fitted curve at depths ranging from 500 to 1000 m; this deviation, though small (of the order of ~0.005 psu and therefore comparable to the CTD accuracy of 0.003 psu), is an order of magnitude larger than the ~0.0003 psu fluctuations associated with the background turbulence or instrument noise in this depth regime, allowing us to infer the existence of RSW throughout the bay. PGW is marked by the presence of a salinity maximum at 200–450 m; in the southwestern bay, PGW can be distinguished from the salinity maximum due to ASHSW because of the intervening Arabian Sea Salinity Minimum. This salinity minimum and the maximum associated with ASHSW disappear east and north of the south-central bay (85°E, 8°N) owing to mixing between the fresher surface waters that are native to the bay (Bay of Bengal Water or BBW) with the high-salinity ASHSW. Hence, ASHSW is not seen as a distinct water mass in the northern and eastern bay and the maximum salinity over most of the bay is associated with PGW. The surface water over most of the bay is therefore a mixture of ASHSW and the low-salinity BBW. As a corollary, we can also infer that the weak oxygen peak seen within the oxygen-minimum zone in the bay at a depth of 250–400 m is associated with PGW. The hydrographic data also show that these three high-salinity water masses are advected into the bay by the Summer Monsoon Current, which is seen to be a deep current extending to 1000 m. These deep currents extend into the northern bay as well, providing a mechanism for spreading ASHSW, PGW, and RSW throughout the bay.

This is a preview of subscription content, log in to check access.

Access options

Buy single article

Instant unlimited access to the full article PDF.

US$ 39.95

Price includes VAT for USA

Subscribe to journal

Immediate online access to all issues from 2019. Subscription will auto renew annually.

US$ 199

This is the net price. Taxes to be calculated in checkout.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10


  1. Amol P, Shankar D, Fernando V, Mukherjee A, Aparna SG, Fernandes R, Michael GS, Khalap ST, Satelkar NP, Agarvadekar Y, Gaonkar MG, Tari AP, Kankonkar A, Vernekar SP (2014) Observed intraseasonal and seasonal variability of the West India Coastal Current on the continental slope. J Earth Syst Sci 123:1045–1074. doi:10.1007/s12040-014-0449-5

  2. Babu VR, Varkey MJ, Das VK, Gouveia AD (1980) Water masses and general hydrography along the west coast of India during early March. Indian J Mar Sci 9:82–89

  3. Banse K (1968) Hydrography of the Arabian Sea shelf of India and Pakistan and effects on demersal fishes. Deep-Sea Res 15:45–79. doi:10.1016/0011-7471(68)90028-4

  4. Banse K, Postel JR (2009) Wintertime convection and ventilation of the upper pycnocline in the northernmost Arabian Sea. Geophys Monogr Ser 185:87–117. doi:10.1029/2008GM000704

  5. Beal LM, Ffield A, Gordon AL (2000) Spreading of Red Sea overflow waters in the Indian Ocean. J Geophys Res 105:8549–8564. doi:10.1029/1999JC900306

  6. Beal LM, Chereskin TK, Bryden HL, Ffield A (2003) Variability of water properties, heat and salt fluxes in the Arabian Sea, between the onset and wane of the 1995 southwest monsoon. Deep-Sea Res Part II 50:2049–2075. doi:10.1016/S0967-0645(03)00045-6

  7. Bonjean F, Lagerloef GSE (2002) Diagnostic model and analysis of the surface currents in the tropical Pacific Ocean. J Phys Oceanogr 32:2938–2954. doi:10.1175/1520-0485(2002)032<2938:DMAAOT>2.0.CO;2

  8. Bower AS, Hunt HD, Price JF (2000) Character and dynamics of the Red Sea and Persian Gulf outflows. J Geophys Res 105:6387–6414. doi:10.1029/1999JC900297

  9. Broecker W (1997) Thermohaline circulation, the Achilles Heel of our climate system: Will man-made CO2 upset the current balance? Science 278:1582–1588. doi:10.1126/science.278.5343.1582

  10. Chatterjee A, Shankar D, Shenoi SSC, Reddy GV, Michael GS, Ravichandran M, Gopalkrishna V, Rao EPR, Bhaskar TVSU, Sanjeevan VN (2012) A new atlas of temperature and salinity for the North Indian Ocean. J Earth Syst Sci 121:559–593. doi:10.1007/s12040-012-0191-9

  11. Darbyshire M (1967) The surface waters off the coast of Kerala, south-west India. Deep-Sea Res 14:295–320. doi:10.1016/0011-7471(67)90073-3

  12. Emery WJ, Meincke J (1986) Global water masses: summary and review. Oceanol Acta 9:383–391

  13. Fine RA, Smethie WM, Bullister JL, Rhein M, Min DH, Warner MJ, Poisson A, Weiss RF (2008) Decadal ventilation and mixing of Indian Ocean waters. Deep-Sea Res Part I 55:20–37. doi:10.1016/j.dsr.2007.10.002

  14. Gallagher JF (1966) The variability of water masses in the Indian Ocean. NODC-Pub-G-11, National Oceanographic Data Center, Washington, DC

  15. Gamsakhurdiya GR, Meschanov SL, Shapiro GI (1991) Seasonal variations in the distribution of Red Sea Waters in the northwestern Indian Ocean. Oceanology 31:32–37

  16. Han W, McCreary JP (2001) Modeling salinity distributions in the Indian Ocean. J Geophys Res 106:859–877. doi:10.1029/2000JC000316

  17. Han W, McCreary JP, Kohler KE (2001) Influence of precipitation minus evaporation and Bay of Bengal rivers on dynamics, thermodynamics, and mixed layer physics in the upper Indian Ocean. J Geophys Res 106:6895–6916. doi:10.1029/2000JC000403

  18. Hastenrath S, Greischar L (1991) The monsoonal current regimes of the tropical Indian Ocean: observed surface flow fields and their geostrophic and wind-driven components. J Geophys Res 96:12619–12633. doi:10.1029/91JC00997

  19. Helland-Hansen B (1916) Nogen hydrografiske metoder. Forhandlinger ved de 16 Skandinaviske Naturforskerermøte. Kristania, Oslo, Norway, pp 357–359

  20. Ivanov-Frantskevich GN (1961) Some peculiarities of hydrography and water masses of the Indian Ocean. In: Oceanology research articles, I. G. Y. Program (Oceanology), vol 4, Acad. Sci. USSR, Moscow, pp 7–18

  21. Jensen TG (2001) Arabian Sea and Bay of Bengal exchange of salt and tracers in an ocean model. Geophys Res Lett 28:3967–3970. doi:10.1029/2001GL013422

  22. Kumar SP, Prasad TG (1999) Formation and spreading of Arabian Sea High-Salinity Water mass. J Geophys Res 104:1455–1464. doi:10.1029/1998JC900022

  23. Levitus S (1982) Climatological atlas of the world ocean. US Gov Printing Office, Rockville, MD NOAA Professional Paper 13

  24. Li-Li X, Yun QIU, Jin-Dian XU, Yun-Kai HE (2012) Hydrography and circulation in the eastern tropical Indian Ocean during April–May 2011. Atmos Ocean Sci Lett 5:284–289

  25. Mamayev OI (1975) Temperature-salinity analysis of world ocean waters. Elsevier Scientific, Amsterdam

  26. McCreary JP, Kundu PK, Molinari RL (1993) A numerical investigation of dynamics, thermodynamics and mixed-layer processes in the Indian Ocean. Prog Oceanogr 31:181–244. doi:10.1016/0079-6611(93)90002-U

  27. McCreary JP, Han W, Shankar D, Shetye SR (1996) Dynamics of the East India Coastal Current: 2. Numerical solutions. J Geophys Res 101:13993–14010. doi:10.1029/96JC00560

  28. McCreary JP, Yu Z, Hood RR, Vinayachandran PN, Furue R, Ishida A, Richards KJ (2013) Dynamics of the Indian-Ocean oxygen minimum zones. Prog Oceanogr 112–113:15–37. doi:10.1016/j.pocean.2013.03.002

  29. Meschanov SL, Shapiro GI (1998) A young lens of Red Sea Water in the Arabian Sea. Deep-Sea Res Part I 45:1–13. doi:10.1016/S0967-0637(97)00018-6

  30. Mukherjee A, Shankar D, Fernando V, Amol P, Aparna SG, Fernandes R, Michael GS, Khalap ST, Satelkar NP, Agarvadekar Y, Gaonkar MG, Tari AP, Kankonkar A, Vernekar S (2014) Observed seasonal and intraseasonal variability of the East India Coastal Current on the continental slope. J Earth Syst Sci 123:1197–1232. doi:10.1007/s12040-014-0471-7

  31. Murray SP, Johns W (1997) Direct observations of seasonal exchange through the Bab el Mandab Strait. Geophys Res Lett 24:2557–2560. doi:10.1029/97GL02741

  32. Murty VSN, Sarma YVB, Rao DP, Murty CS (1992) Water characteristics, mixing and circulation in the Bay of Bengal during southwest monsoon. J Mar Res 50:207–228. doi:10.1357/002224092784797700

  33. Naqvi SWA (1987) Some aspects of the oxygen-deficient conditions and denitrification in the Arabian Sea. J Mar Res 45:1049–1072. doi:10.1357/002224087788327118

  34. Naqvi SWA (1991) Geographical extent of denitrification in the Arabian Sea in relation to some physical processes. Oceanol Acta 14:281–290

  35. Prasad TG, Ikeda M (2002) A numerical study of the seasonal variability of Arabian Sea High-Salinity Water. J Geophys Res 107:3197. doi:10.1029/2001JC001139

  36. Prasad TG, Ikeda M, Kumar SP (2001) Seasonal spreading of the Persian Gulf Water mass in the Arabian Sea. J Geophys Res 106:17059–17071. doi:10.1029/2000JC00048

  37. Premkumar K, Ravichandran M, Kalsi SR, Sengupta D, Gadgil S (2000) First results from a new observational system over the Indian seas. Curr Sci 78:323–331

  38. Rao SA, Saha SK, Pokhrel S, Sundar D, Dhakate AR, Mahapatra S, S A, Chaudhari H, Sreeram P, Vasimalla S, Srikanth AS, Suresh RRV (2011) Modulation of SST, SSS over northern Bay of Bengal on ISO time scale. J Geophys Res. doi:10.1029/2010JC006804

  39. Rochford DJ (1964) Salinity maxima in the upper 1000 metres of the North Indian Ocean. Aust J Mar Freshw Res 15:1–24

  40. Saafani MAA (2008) Physical oceanography of the Gulf of Aden. Ph.D. thesis, Goa University, Goa, India

  41. Saafani MAA, Shenoi SSC (2004) Seasonal cycle of hydrography in the Bab el Mandab region, southern Red Sea. J Earth Syst Sci 113:269–280. doi:10.1007/BF02716725

  42. Saafani MAA, Shenoi SSC (2007) Water masses in the Gulf of Aden. J Oceanogr 63:1–14. doi:10.1007/s10872-007-0001-1

  43. Sardessai S, Ramaiah N, Kumar SP, de Sousa SN (2007) Influence of environmental forcings on the seasonality of dissolved oxygen and nutrients in the Bay of Bengal. J Mar Res 65:301–316

  44. Sastry JS, Rao DP, Murty VSN, Sarma YVB, Suryanarayana A, Babu MT (1985) Watermass structure in the Bay of Bengal. Mahasagar 18:153–162

  45. Schott FA, McCreary JP (2001) The monsoon circulation of the Indian Ocean. Prog Oceanogr 51:1–123. doi:10.1016/S0079-6611(01)00083-0

  46. Schott F, Reppin J, Fischer J, Quadfasel D (1994) Currents and transports of the Monsoon Current South of Sri Lanka. J Geophys Res 99:25127–25141. doi:10.1029/94JC02216

  47. Schott FA, Xie SP, McCreary JP (2009) Indian Ocean circulation and climate variability. Rev Geophys. doi:10.1029/2007RG000245

  48. Shankar D, Shetye SR (1997) On the dynamics of the Lakshadweep high and low in the southeastern Arabian Sea. J Geophys Res 102:12551–12562. doi:10.1029/97JC00465

  49. Shankar D, McCreary JP, Han W, Shetye SR (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. doi:10.1029/96JC00559

  50. Shankar D, Vinayachandran PN, Unnikrishnan AS (2002) The monsoon currents in the north Indian Ocean. Prog Oceanogr 52:63–120. doi:10.1016/S0079-6611(02)00024-1

  51. Shankar D, Shenoi SSC, Nayak RK, Vinayachandran PN, Nampoothiri G, Almeida AM, Michael GS, Kumar MR, Sundar D, Sreejith OP (2005) Hydrography of the eastern Arabian Sea during summer monsoon 2002. J Earth Syst Sci 114:459–474. doi:10.1007/BF02702023

  52. Shankar D, Remya R, Vinayachandran PN, Chatterjee A, Behera A (2015) Inhibition of mixed-layer deepening during winter in the northeastern Arabian Sea by the West India Coastal Current. Clim Dyn. doi:10.1007/s00382-015-2888-3

  53. Shapiro GI, Meschanov SL (1991) Distribution and spreading of Red Sea Water and salt lens formation in the northwest Indian Ocean. Deep-Sea Res Part I 38:21–34. doi:10.1016/0198-0149(91)90052-H

  54. Shenoi SSC, Shetye SR, Gouveia AD, Michael GS (1993) Salinity extrema in the Arabian Sea. In: Ittekkot V, Nair RR (eds) Monsoon biogeochemistry, Mitteilungen des Geologisch-Paläontologischen Instituts der Universität Hamburg, University of Hamburg, Germany, pp 37–49

  55. Shenoi SSC, Shankar D, Shetye SR (2002) Differences in heat budgets of the near-surface Arabian Sea and Bay of Bengal: implications for the summer monsoon. J Geophys Res. doi:10.1029/2000JC000679

  56. Shenoi SSC, Shankar D, Michael GS, Kurian J, Varma KK, Kumar MRR, Almeida AM, Unnikrishnan AS, Fernandes W, Barreto N, Gnanaseelan C, Mathew R, Praju KV, Mahale V (2005) Hydrography and water masses in the southeastern Arabian Sea during March–June 2003. J Earth Syst Sci 114:475–491. doi:10.1007/BF02702024

  57. Shetye SR, Shenoi SSC, Gouveia AD, Michael GS, Sundar D, Nampoothiri G (1991) Wind-driven coastal upwelling along the western boundary of the Bay of Bengal during the southwest monsoon. Cont Shelf Res 11:1397–1408. doi:10.1016/0278-4343(91)90042-5

  58. Shetye SR, Gouveia AD, Shenoi SSC (1992) Does winter cooling lead to the subsurface salinity minimum off Saurashtra, India. In: Desai BN (ed) Oceanography of the Indian Ocean. Oxford and India Book House, Oxford

  59. Shetye SR, Gouveia AD, Shenoi SSC, Sundar D, Michael GS, Nampoothiri G (1993) The western boundary current of the seasonal subtropical gyre in the Bay of Bengal. J Geophys Res 98:945–954. doi:10.1029/92JC02070

  60. Shetye SR, Gouveia AD, Shenoi SSC (1994) Circulation and water masses of the Arabian Sea. Proc Indian Acad Sci (Earth Planet Sci) 103:107–123. doi:10.1007/BF02839532 (special issue: Biogeochemistry of the Arabian Sea)

  61. Shetye SR, Gouveia AD, Shankar D, Shenoi SSC, Vinayachandran PN, Sundar D, Michael GS, Nampoothiri G (1996) Hydrography and circulation in the western Bay of Bengal during the northeast monsoon. J Geophys Res 101:14,011–14,025. doi:10.1029/95JC03307

  62. Sprintall J, Tomczak M (1993) On the formation of Central Water and thermocline ventilation in the southern hemisphere. Deep-Sea Res Part I 40:827–848. doi:10.1016/0967-0637(93)90074-d

  63. Stommel HM (1966) The large-scale oceanic circulation. In: Hurley P (ed) Advances in Earth science. MIT Press, Cambridge, pp 175–184

  64. Subeesh MP, Unnikrishnan AS, Fernando V, Agarwadekar Y, Khalap ST, Satelkar NP, Shenoi SSC (2013) Observed tidal currents on the continental shelf off the west coast of India. Cont Shelf Res 69:123–140. doi:10.1016/j.csr.2013.09.008

  65. Sverdrup HU, Johnson MW, Fleming RH (1942) The water masses and currents of the oceans. The oceans their physics, chemistry, and general biology. Prentice-Hall, New York, pp 605–761

  66. Talley LD, Pickard GL, Emery WJ, Swift JH (2011) Descriptive physical oceanography: an introduction, 6th edn. Elsevier, Amsterdam

  67. Varadachari VVR, Murty CS, Reddy CVG (1968) Salinity maxima associated with some sub-surface water masses in the upper layers of the Bay of Bengal. Bull Natl Inst Sci India 38:338–343

  68. Vinayachandran PN, Yamagata T (1998) Monsoon response of the sea around Sri Lanka: generation of thermal domes and anticyclonic vortices. J Phys Oceanogr 28:1946–1960. doi:10.1175/1520-0485(1998)028<1946:MROTSA>2.0.CO%3B2

  69. Vinayachandran PN, Masumoto Y, Mikawa T, Yamagata T (1999) Intrusion of the Southwest Monsoon Current into the Bay of Bengal. J Geophys Res 104:11077–11085. doi:10.1029/1999JC900035

  70. Vinayachandran PN, Murty VSN, Babu VR (2002) Observations of barrier layer formation in the Bay of Bengal during summer monsoon. J Geophys Res. doi:10.1029/2001JC000831

  71. Vinayachandran PN, Shankar D, Vernekar S, Sandeep KK, Amol P, Neema CP, Chatterjee A (2013) A summer monsoon pump to keep the Bay of Bengal salty. Geophys Res Lett 40:1777–1782. doi:10.1002/grl.50274

  72. Wijesekera HW, Jensen TG, Jarosz E, Teague WJ, Metzger EJ, Wang DW, Jinadasa SUP, Arulananthan K, Centurioni LR, Fernando HJS (2015) Southern Bay of Bengal currents and salinity intrusions during the northeast monsoon. J Geophys Res. doi:10.1002/2015JC010744

  73. Worthington LV (1981) The water masses of the world ocean: Some results of a fine-scale census. Evolution of physical oceanography: Scientific surveys in honor of Henry Stommel. MIT Press, Cambridge, pp 42–69

  74. Wunsch C (2002) What is the thermohaline circulation? Science 298:1179–1181. doi:10.1126/science.1079329

  75. Wyrtki K (1971) Oceanographic atlas of the International Indian Ocean expedition. National Science Foundation, Washington

  76. Wyrtki K (1973a) An equatorial jet in the Indian Ocean. Science 181:262–264. doi:10.1126/science.181.4096.262

  77. Wyrtki K (1973b) Physical oceanography of the Indian Ocean. In: Zeitzschel B (ed) The biology of the Indian Ocean. Springer, Berlin, pp 18–36

  78. You Y, Tomczak M (1993) Thermocline circulation and ventilation in the Indian Ocean derived from water mass analysis. Deep-Sea Res Part I 40:13–56. doi:10.1016/0967-0637(93)90052-5

Download references


We thank Satheesh Shenoi and Virupaxa Banakar for useful discussions on water masses and T. V. S. Udaya Bhaskar for clarifications on Argo protocols. This paper has benefitted considerably from the critical comments from Julian McCreary and three anonymous reviewers. We thank the masters, officers, and crew of all the cruises for their assistance, and the personnel from Elcome Marine (for SK-175), Norinco (for SN-065 and SK-296), and the CSIR-NIO ship cell (Mahesh Korgaonkar and Buddhadas Patole for SSK-047, Shashikant Velip and M. Kalliathan for SSK-062, and Santosh Gawas and Amey Kambli for SSK-070) for their assistance in collecting the CTD data. DS acknowledges the contribution of his colleagues on cruise SK-175 (M. Dileep Kumar, P. S. Rao, Y. K. Somayajulu, U Chit Kyaw, U Ye Lwin, and Comdr. S. K. Mishra) in collecting the CTD data. The Argo data were collected and made freely available by the International Argo Program and the national programmes that contribute to it (, The Argo Programme is part of the Global Ocean Observing System. Ferret was used extensively for analysis and GMT (Generic Mapping Tools) for graphics. Funding for this work came from the Ministry of Earth Sciences (Government of India) through their CTCZ (Continental Tropical Convergence Zone) programme; additional support was provided by CSIR (Council of Scientific and Industrial Research, New Delhi) through the programme OCEAN FINDER. VJ acknowledges funding support from CSIR and Charls Antony’s help with GMT. This is CSIR-NIO contribution 5916 and ESSO-INCOIS contribution 262. We dedicate this paper to Bhuvaneshwari Sridhar, our young colleague on SN-065, who passed away in a tragic accident in March 2014.

Author information

Correspondence to D. Shankar.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Supplementary material 2 (mpg 10061 KB)

Supplementary material 1 (pdf 408 KB)

Supplementary material 2 (mpg 10061 KB)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Jain, V., Shankar, D., Vinayachandran, P.N. et al. Evidence for the existence of Persian Gulf Water and Red Sea Water in the Bay of Bengal. Clim Dyn 48, 3207–3226 (2017) doi:10.1007/s00382-016-3259-4

Download citation


  • Water masses
  • Indian Ocean
  • Arabian Sea High-Salinity Water
  • Persian Gulf Water
  • Red Sea Water
  • Oxygen minimum zone
  • Summer Monsoon Current
  • CTD