Skip to main content
Log in

A study of Indian Ocean Subtropical Mode Water: subduction rate and water characteristics

  • Published:
Acta Oceanologica Sinica Aims and scope Submit manuscript

Abstract

The annual subduction rate in the South Indian Ocean was calculated by analyzing Simple Ocean Data Assimilation (SODA) outputs in the period of 1950–2008. The subduction rate census for potential density classes showed a peak corresponding to Indian Ocean subtropical mode water (IOSTMW) in the southwestern part of the South Indian Ocean subtropical gyre. The deeper mixed layer depth, the sharper mixed-layer fronts and the associated relatively faster circulation in the present climatology resulted in a larger lateral induction, which primarily dominants the IOSTMW subduction rate, while with only minor contribution from vertical pumping. Without loss of generality, through careful analysis of the water characteristics in the layer of minimum vertical temperature gradient (LMVTG), the authors suggest that the IOSTMW was identified as a thermostad, with a lateral minimum of low potential vorticity (PV, less than 200×10–12 m–1·s–1) and a low dT⁄dz (less than 1.5°C/(100 m)). The IOSTMW within the South Indian Ocean subtropical gyre distributed in the region approximately from 25° to 50° E and from 30° to 39°S. Additionally, the average characteristics (temperature, salinity, potential density) of the mode water were estimated about (16.38 ± 0.29)°C, (35.46 ± 0.04), (26.02 ± 0.04) σ θ over the past 60 years.

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

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  • Aoki S, Hariyama M, Mitsudera H, et al. 2007. Formation regions of Subantarctic Mode Water detected by OFES and Argo profiling floats. Geophys Res Lett, 34(10): L10606

    Article  Google Scholar 

  • Bingham F M. 1992. Formation and spreading of Subtropical Mode Water in the North Pacific. J Geophys Res, 97(C7): 11177–11189

    Article  Google Scholar 

  • Cai Wenju, Santoso A, Wang Guojian, et al. 2014. Increased frequency of extreme Indian Ocean Dipole events due to greenhouse warming. Nature, 510(7504): 254–258

    Article  Google Scholar 

  • Downes S M, Bindoff N L, Rintoul S R. 2009. Impacts of climate change on the subduction of mode and intermediate water masses in the Southern Ocean. J Climate, 22(12): 3289–3302

    Article  Google Scholar 

  • Fine R A. 1993. Circulation of Antarctic intermediate water in the South Indian Ocean. Deep-Sea Research Part I: Oceanographic Research Papers, 40(10): 2021–2042

    Article  Google Scholar 

  • Gu Daifang, Philander S G H. 1997. Interdecadal climate fluctuations that depend on exchanges between the tropics and extratropics. Science, 275(5301): 805–807

    Article  Google Scholar 

  • Hanawa K. 1987. Interannual variations of the winter-time outcrop area of subtropical mode water in the Western North Pacific Ocean. Atmosphere-Ocean, 25(4): 358–374

    Article  Google Scholar 

  • Hanawa K, Talley L D. 2001. Mode waters, in ocean circulation and climate. In: Siedler G, Griffies S M, Gould J, et al., eds. International Geophysics Series. Waltham, USA: Academy Press, 77: 373–386

    Google Scholar 

  • Huang Ruixin, Qiu Bo. 1998. The structure of the wind-driven circulation in the subtropical South Pacific Ocean. J Phys Oceanogr, 28(6): 1173–1186

    Article  Google Scholar 

  • Iselin C O’D. 1939. The influence of vertical and lateral turbulence on the characteristics of the waters at mid-depths. Trans Amer Geophys Union, 20(3): 414–417

    Article  Google Scholar 

  • Jenkins W J. 1982. On the climate of a subtropical ocean gyre: Decade timescale variations in water mass renewal in the Sargasso Sea. J Mar Res, 40 (Suppl): 265–290

    Google Scholar 

  • Josey S A, Kent E C, Taylor P K. 1999. New insights into the ocean heat budget closure problem from analysis of the SOC air-sea flux climatology. J Climate, 12(9): 2856–2880

    Article  Google Scholar 

  • Karstensen J, Quadfasel D. 2002. Formation of southern hemisphere thermocline waters: Water mass conversion and subduction. J Phys Oceanogr, 32(11): 3020–3038

    Article  Google Scholar 

  • Kobayashi T, Suga T. 2006. The Indian Ocean HydroBase: A highquality climatological dataset for the Indian Ocean. Prog Oceanogr, 68(1): 75–114

    Article  Google Scholar 

  • Koch-Larrouy A, Morrow R, Penduff T, et al. 2010. Origin and mechanism of subantarctic mode water formation and transformation in the southern indian ocean. Ocean Dynamics, 60(3): 563–583

    Article  Google Scholar 

  • Lu Peng, McCreary Jr J P, Klinger B A. 1998. Meridional circulation cells and the source waters of the Pacific equatorial undercurrent. J Phys Oceanogr, 28(1): 62–84

    Article  Google Scholar 

  • Marshall J C, Williams R G, Nurser A J G. 1993. Inferring the subduction rate and period over the North Atlantic. J Phys Oceanogr, 23(7): 1315–1329

    Article  Google Scholar 

  • Masuzawa J. 1969. Subtropical mode water. Deep-Sea Research and Oceanographic Abstracts, 16(5): 463–472

    Article  Google Scholar 

  • Maze G, Forget G, Buckley M, et al. 2009. Using transformation and formation maps to study the role of air–sea heat fluxes in North Atlantic Eighteen Degree Water formation. J Phys Oceanogr, 39(8): 1818–1835

    Article  Google Scholar 

  • McCartney M S. 1982. The subtropical recirculation of mode waters. J Mar Res, 40(Supp): 427–464

    Google Scholar 

  • McDonagh E L, Bryden H L, King B A, et al. 2005. Decadal changes in the south Indian Ocean thermocline. J Climate, 18(10): 1575–1590

    Article  Google Scholar 

  • Metzl N, Tilbrook B, Poisson A. 1999. The annual fCO2 cycle and the air–sea CO2 flux in the sub-Antarctic Ocean. Tellus B, 51(4): 849–861

    Article  Google Scholar 

  • Miyama T, McCreary Jr J P, Jensen T G, et al. 2003. Structure and dynamics of the Indian-Ocean cross-equatorial cell. Deep Sea Research Part II: Topical Studies in Oceanography, 50(12–13): 2023–2047

    Article  Google Scholar 

  • Olson D B, Fine R A, Gordon A L. 1992. Convective modifications of water masses in the Agulhas. Deep-Sea Research Part A. Oceanographic Research Papers, 39(Supp 1): S163–S181

    Article  Google Scholar 

  • Poisson A, Metzl N, Brunet C, et al. 1993. Variability of sources and sinks of CO2 in the Western Indian and Southern Oceans during 1991. J Geophys Res, 98(C12): 22759–22778

    Article  Google Scholar 

  • Qiu Bo, Huang Ruixin. 1995. Ventilation of the North Atlantic and North Pacific: Subduction versus obduction. J Phys Oceanogr, 25(10): 2374–2390

    Article  Google Scholar 

  • Qu Tangdong, Chen Ju. 2009. A North Pacific decadal variability in subduction rate. Geophys Res Lett, 36(22): L22602

    Google Scholar 

  • Qu Tangdong, Xie Shangping, Mitsudera H, et al. 2002. Subduction of the North Pacific mode waters in a global high-resolution GCM. J Phys Oceanogr, 32(3): 746–763

    Article  Google Scholar 

  • Roemmich D, Cornuelle B. 1992. The subtropical mode waters of the South Pacific Ocean. J Phys Oceanogr, 22(10): 1178–1187

    Article  Google Scholar 

  • Sabine Christopher L, Richard A Feely, Nicolas Gruber, et al. 2004. The oceanic sink for anthropogenic CO2. Science, 305(5082): 367–371

    Article  Google Scholar 

  • Saenko O A, Yang Xiaoyi, England M H, et al. 2011. Subduction and transport in the Indian and Pacific Oceans in a 2 climate. J Climate, 24(6): 1821–1838

    Article  Google Scholar 

  • Sallée J B, Wienders N, Speer K, et al. 2006. Formation of subantarctic mode water in the southeastern Indian Ocean. Ocean Dynamics, 56(5–6): 525–542

    Article  Google Scholar 

  • Sarmiento J L. 1983. A tritium box model of the North Atlantic thermocline. J Phys Oceanogr, 13(7): 1269–1274

    Article  Google Scholar 

  • Schneider N, Miller A J, Alexander M A, et al. 1999. Subduction of decadal North Pacific temperature anomalies: Observations and dynamics. J Phys Oceanogr, 29(5): 1056–1070

    Article  Google Scholar 

  • Schott F A, Dengler M, Schoenefeldt R. 2002. The shallow overturning circulation of the Indian Ocean. Progress in Oceanography, 53(1): 57–103

    Article  Google Scholar 

  • Smith R D, Dukowicz J K, Malone R C. 1992. Parallel ocean general circulation modeling. Physica D: Nonlinear Phenomena, 60(1–4): 38–61

    Article  Google Scholar 

  • Stommel H M. 1979. Determination of water mass properties of water pumped down from the Ekman layer to the geostrophic flow below. Proc Natl Acad Sci U S A, 76(7): 3051–3055

    Article  Google Scholar 

  • Stramma L, Lutjeharms J R E. 1997. The flow field of the subtropical gyre of the South Indian Ocean. J Geophys Res, 102(C3): 5513–5530

    Article  Google Scholar 

  • Talley L D, Raymer M E. 1982. Eighteen degree water variability. J Mar Res, 40(Supp): 757–775

    Google Scholar 

  • Toole J M, Warren B A. 1993. A hydrographic section across the subtropical South Indian Ocean. Deep-Sea Research Part I: Oceanographic Research Papers, 40(10): 1973–2019

    Article  Google Scholar 

  • Tsubouchi T, Suga T, Hanawa K. 2010. Indian Ocean Subtropical Mode Water: its water characteristics and spatial distribution. Ocean Science, 6(1): 41–50

    Article  Google Scholar 

  • Warren B A. 1972. Insensitivity of subtropical mode water characteristics to meteorological fluctuations. Deep-Sea Research and Oceanographic Abstracts, 19(1): 1–19

    Article  Google Scholar 

  • Williams R G. 1989. The influence of air–sea interaction on the ventilated thermocline. J Phys Oceanogr, 19(9): 1255–1267

    Article  Google Scholar 

  • Wong A P S. 2005. Subantarctic Mode Water and Antarctic Intermediate Water in the South Indian Ocean based on profiling float data 2000–2004. J Mar Res, 63(4): 789–812

    Article  Google Scholar 

  • Woods J D. 1985. The physics of thermocline ventilation. Elsevier Oceanography Series, 40: 543–590

    Article  Google Scholar 

  • Worthington L V. 1959. The 18 water in the Sargasso Sea. Deep-Sea Research, 5(2–4): 297–305

    Google Scholar 

  • Worthington L V. 1976. On the North Atlantic Circulation. Baltimore: The Johns Hopkins University Press, 110

    Google Scholar 

  • Yasuda T, Hanawa K. 1997. Decadal changes in the mode waters in the midlatitude North Pacific. J Phys Oceanogr, 27(6): 858–870

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Jian Lan.

Additional information

Foundation item: The National Natural Science Foundation of China under contract Nos 41276011 and 41221063; the Research Project of Chinese Ministry of Education under contract No. 113041A; the Global Change and Air-Sea Interaction under contract under contract No. GASI-03-01-01-05.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Ma, J., Lan, J. & Zhang, N. A study of Indian Ocean Subtropical Mode Water: subduction rate and water characteristics. Acta Oceanol. Sin. 35, 38–45 (2016). https://doi.org/10.1007/s13131-016-0794-0

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s13131-016-0794-0

Key words

Navigation