• Anderson, D., and A. E. Gill, 1975: Spin-up of a stratified ocean, with applications to upwelling. Deep-Sea Res., 22, 583596, https://doi.org/10.1016/0011-7471(75)90046-7.

    • Search Google Scholar
    • Export Citation
  • Anderson, D., and P. D. Killworth, 1977: Spin-up of a stratified ocean, with topography. Deep-Sea Res., 24, 709732, https://doi.org/10.1016/0146-6291(77)90495-7.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Atlas, R., J. Ardizzone, and R. N. Hoffman, 2008: Application of satellite surface wind data to ocean wind analysis. Proc. SPIE, 7087, 70870B, https://doi.org/10.1117/12.795371.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Balmaseda, M. A., K. E. Trenberth, and E. Källén, 2013: Distinctive climate signals in reanalysis of global ocean heat content. Geophys. Res. Lett., 40, 17541759, https://doi.org/10.1002/grl.50382.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chamberlain, M. A., P. R. Oke, R. A. S. Fiedler, H. M. Beggs, and P. Divakaran, 2021: Next generation of Bluelink ocean reanalysis with multiscale data assimilation: BRAN2020. Earth Syst. Sci. Data, 13, 56635688, https://doi.org/10.5194/essd-13-5663-2021.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chen, G., W. Han, Y. Li, D. Wang, and M. J. McPhaden, 2015: Seasonal-to-interannual time-scale dynamics of the equatorial undercurrent in the Indian Ocean. J. Phys. Oceanogr., 45, 15321553, https://doi.org/10.1175/JPO-D-14-0225.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chen, G., W. Han, Y. Li, M. J. McPhaden, J. Chen, W. Wang, and D. Wang, 2017: Strong intraseasonal variability of meridional currents near 5°N in the eastern Indian Ocean: Characteristics and causes. J. Phys. Oceanogr., 47, 979998, https://doi.org/10.1175/JPO-D-16-0250.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chen, G., W. Han, Y. Li, J. Yao, and D. Wang, 2019: Intraseasonal variability of the equatorial undercurrent in the Indian Ocean. J. Phys. Oceanogr., 49, 85101, https://doi.org/10.1175/JPO-D-18-0151.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cox, M. D., 1979: A numerical study of Somali Current eddies. J. Phys. Oceanogr., 9, 311326, https://doi.org/10.1175/1520-0485(1979)009<0311:ANSOSC>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dee, D. P., and Coauthors, 2011: The ERA-Interim reanalysis: Configuration and performance of the data assimilation system. Quart. J. Roy. Meteor. Soc., 137, 553597, https://doi.org/10.1002/qj.828.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Donguy, J.-R., and G. Meyers, 1995: Observations of geostrophic transport variability in the western tropical Indian Ocean. Deep-Sea Res. I, 42, 10071028, https://doi.org/10.1016/0967-0637(95)00047-A.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hautala, S. L., D. H. Roemmich, and W. J. Schmilz Jr., 1994: Is the North Pacific in Sverdrup balance along 24°N? J. Geophys. Res., 99, 16 04116 052, https://doi.org/10.1029/94JC01084.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hurlburt, H., and J. D. Thompson, 1976: A numerical model of the Somali Current. J. Phys. Oceanogr., 6, 646664, https://doi.org/10.1175/1520-0485(1976)006<0646:ANMOTS>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kobayashi, S., and Coauthors, 2015: The JRA-55 Reanalysis: General specifications and basic characteristics. J. Meteor. Soc. Japan, 93, 548, https://doi.org/10.2151/jmsj.2015-001.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kummerow, C., W. Barnes, T. Kozu, J. Shiue, and J. Simpson, 1998: The Tropical Rainfall Measuring Mission (TRMM) sensor package. J. Atmos. Oceanic Technol., 15, 809817, https://doi.org/10.1175/1520-0426(1998)015<0809:TTRMMT>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Leetmaa, A., P. Niiler, and H. Stommel, 1977: Does the Sverdrup relation account for the mid-Atlantic circulation? J. Mar. Res., 35, 110.

    • Search Google Scholar
    • Export Citation
  • Le Traon, P., F. Nadal, and N. Ducet, 1998: An improved mapping method of multisatellite altimeter data. J. Atmos. Oceanic Technol., 15, 522534, https://doi.org/10.1175/1520-0426(1998)015<0522:AIMMOM>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Li, Y., W. Han, T. Shinoda, C. Wang, M. Ravichandran, and J.-W. Wang, 2014: Revisiting the wintertime intraseasonal SST variability in the tropical south Indian Ocean: Impact of the ocean interannual variation. J. Phys. Oceanogr., 44, 18861907, https://doi.org/10.1175/JPO-D-13-0238.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Li, Y., W. Han, W. Wang, M. Ravichandran, T. Lee, and T. Shinoda, 2017: Bay of Bengal salinity stratification and Indian summer monsoon intraseasonal oscillation: 2. Impact on SST and convection. J. Geophys. Res. Oceans, 122, 43124328, https://doi.org/10.1002/2017JC012692.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Loeb, N. G., K. J. Priestley, D. P. Kratz, E. B. Geier, R. N. Green, B. A. Wielicki, P. O’ Rawe Hinton, and S. K. Nolan, 2001: Determination of unfiltered radiances from the Clouds and the Earth′s Radiant Energy System instrument. J. Appl. Meteor., 40, 822835, https://doi.org/10.1175/1520-0450(2001)040%3C0822:DOURFT%3E2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Luther, M. E., and J. J. O’Brien, 1985: A model of the seasonal circulation in the Arabian Sea forced by observed winds. Prog. Oceanogr., 14, 353385, https://doi.org/10.1016/0079-6611(85)90017-5.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McCreary, J. P., Jr., and P. K. Kundu, 1988: A numerical investigation of the Somali Current during the Southwest Monsoon. J. Mar. Res., 46, 2558, https://doi.org/10.1357/002224088785113711.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McCreary, J. P., Jr, P. K. Kundu, and R. L. Molinari, 1993: A numerical investigation of dynamics, thermodynamics and mixed-layer processes in the Indian Ocean. Prog. Oceanogr., 31, 181244, https://doi.org/10.1016/0079-6611(93)90002-U.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Meyers, G., 1980: Do Sverdrup transports account for the Pacific North Equatorial Countercurrent? J. Geophys. Res., 85, 10731075, https://doi.org/10.1029/JC085iC02p01073.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Philander, S., and P. Delecluse, 1983: Coastal currents in low latitudes (with application to the Somali and El Niño currents). Deep-Sea Res., 30A, 887902, https://doi.org/10.1016/0198-0149(83)90006-7.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Qiu, B., 2002: Large-scale variability in the midlatitude subtropical and subpolar North Pacific Ocean: Observations and causes. J. Phys. Oceanogr., 32, 353375, https://doi.org/10.1175/1520-0485(2002)032<0353:LSVITM>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Schmitz, W. J., Jr., J. D. Thompson, and J. R. Luyten, 1992: The Sverdrup circulation for the Atlantic along 24°N. J. Geophys. Res., 97, 72517256, https://doi.org/10.1029/92JC00417.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Schott, F. A., and J. Fischer, 2000: Winter monsoon circulation of the northern Arabian Sea and Somali Current. J. Geophys. Res., 105, 63596376, https://doi.org/10.1029/1999JC900312.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Schott, F. A., and J. P. McCreary Jr., 2001: The monsoon circulation of the Indian Ocean. Prog. Oceanogr., 51, 1123, https://doi.org/10.1016/S0079-6611(01)00083-0.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sverdrup, H. U., 1947: Wind-driven currents in a baroclinic ocean; with application to the equatorial currents of the eastern Pacific. Proc. Natl. Acad. Sci. USA, 33, 318326, https://doi.org/10.1073/pnas.33.11.318.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Thomas, M. D., A. M. De Boer, H. L. Johnson, and D. P. Stevens, 2014: Spatial and temporal scales of Sverdrup balance. J. Phys. Oceanogr., 44, 26442660, https://doi.org/10.1175/JPO-D-13-0192.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tsujino, H., and Coauthors, 2020: input4MIPs.CMIP6.OMIP.MRI.MRI-JRA55-do-1-5-0. Earth System Grid Federation, accessed 16 September 2020, https://doi.org/10.22033/ESGF/input4MIPs.15017.

    • Search Google Scholar
    • Export Citation
  • Wang, H., J. L. McClean, L. D. Talley, and S. G. Yeager, 2018: Seasonal cycle and annual reversal of the Somali Current in an eddy-resolving global ocean model. J. Geophys. Res. Oceans, 123, 65626580, https://doi.org/10.1029/2018JC013975.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wentz, F. J., J. Scott, R. Hoffman, M. Leidner, R. Atlas, and J. Ardizzone, 2015: Remote Sensing Systems Cross-Calibrated Multi-Platform (CCMP) 6-hourly ocean vector wind analysis product on 0.25 deg grid, version 2.0. Remote Sensing Systems, accessed 9 October 2018, www.remss.com/measurements/ccmp.

    • Search Google Scholar
    • Export Citation
  • Wielicki, B. A., B. R. Barkstrom, E. F. Harrison, R. B. Lee, G. L. Smith, and J. E. Cooper, 1996: Clouds and the Earth’s Radiant Energy System (CERES): An Earth Observing System experiment. Bull. Amer. Meteor. Soc., 77, 853868, https://doi.org/10.1175/1520-0477(1996)077<0853:CATERE>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wunsch, C., 2011: The decadal mean ocean circulation and Sverdrup balance. J. Mar. Res., 69, 417434, https://doi.org/10.1357/002224011798765303.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wunsch, C., and D. Roemmich, 1985: Is the North Atlantic in Sverdrup balance? J. Phys. Oceanogr., 15, 18761880, https://doi.org/10.1175/1520-0485(1985)015<1876:ITNAIS>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yuan, D., Z. Zhang, P. C. Chu, and W. K. Dewar, 2014: Geostrophic circulation in the tropical North Pacific Ocean based on Argo profiles. J. Phys. Oceanogr., 44, 558575, https://doi.org/10.1175/JPO-D-12-0230.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
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A Time-Dependent Sverdrup Relation and Its Application to the Indian Ocean

Gengxin ChenaState Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
bSouthern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
cInnovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, China

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Rui Xin HuangdDepartment of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts

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Qihua PengeScripps Institution of Oceanography, University of California, San Diego, La Jolla, California

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Xiaoqing ChuaState Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
bSouthern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China

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Abstract

The Sverdrup relation is the backbone of wind-driven circulation theory; it is a simple relation between the meridional transport of the wind-driven circulation in the upper ocean and the wind stress curl. However, the relation is valid for steady circulation only. In this study, a time-dependent Sverdrup relation is postulated, in which the meridional transport in a time-dependent circulation is the sum of the local wind stress curl term and a time-delayed term representing the effect of the eastern boundary condition. As an example, this time-dependent Sverdrup relation is evaluated through its application to the equatorial circulation in the Indian Ocean, using reanalysis data and a reduced gravity model. Close examination reveals that the southward Somali Current occurring during boreal winter is due to the combination of the local wind stress curl in the Arabian Sea and delayed signals representing the time change of layer thickness at the eastern boundary.

Significance Statement

Sverdrup balance dictates the law of meridional transport of steady circulation in the upper ocean, and has been one of the foundations upon which our understanding of ocean circulation is built. However, for circulation forced by time-varying wind stress, with annual, interannual and decadal frequency, the governing law remains elusive. In this study, we introduce a time-dependent Sverdrup relation applicable to time-dependent wind-driven circulation. As an example, this relation is used to diagnose the monsoon-driven circulation in the Indian Ocean.

© 2022 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Xiaoqing Chu, chuxq@scsio.ac.cn

Abstract

The Sverdrup relation is the backbone of wind-driven circulation theory; it is a simple relation between the meridional transport of the wind-driven circulation in the upper ocean and the wind stress curl. However, the relation is valid for steady circulation only. In this study, a time-dependent Sverdrup relation is postulated, in which the meridional transport in a time-dependent circulation is the sum of the local wind stress curl term and a time-delayed term representing the effect of the eastern boundary condition. As an example, this time-dependent Sverdrup relation is evaluated through its application to the equatorial circulation in the Indian Ocean, using reanalysis data and a reduced gravity model. Close examination reveals that the southward Somali Current occurring during boreal winter is due to the combination of the local wind stress curl in the Arabian Sea and delayed signals representing the time change of layer thickness at the eastern boundary.

Significance Statement

Sverdrup balance dictates the law of meridional transport of steady circulation in the upper ocean, and has been one of the foundations upon which our understanding of ocean circulation is built. However, for circulation forced by time-varying wind stress, with annual, interannual and decadal frequency, the governing law remains elusive. In this study, we introduce a time-dependent Sverdrup relation applicable to time-dependent wind-driven circulation. As an example, this relation is used to diagnose the monsoon-driven circulation in the Indian Ocean.

© 2022 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Xiaoqing Chu, chuxq@scsio.ac.cn

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