Comparison of Eight Detection Algorithms for the Quantification and Characterization of Mesoscale Eddies in the South China Sea

Zhan Lian Laboratory of Marine Science and Numerical Modeling, First Institute of Oceanography, State Oceanic Administration, and Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.

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Baonan Sun Laboratory of Marine Science and Numerical Modeling, First Institute of Oceanography, State Oceanic Administration, and Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.

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Zexun Wei Laboratory of Marine Science and Numerical Modeling, First Institute of Oceanography, State Oceanic Administration, and Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.

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Yonggang Wang Laboratory of Marine Science and Numerical Modeling, First Institute of Oceanography, State Oceanic Administration, and Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.

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Xinyi Wang Laboratory of Marine Science and Numerical Modeling, First Institute of Oceanography, State Oceanic Administration, and Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.

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Abstract

Numerous oceanic mesoscale eddies occur in the South China Sea (SCS). The present study employs eight automatic eddy detection algorithms to identify these mesoscale eddies and compares the results. Eddy probabilities and areas detected by various algorithms differ substantially. Most regions of the SCS with a high discrepancy of eddy probabilities are those with few mesoscale eddies, except for the area west of the Luzon Strait, the area west of Luzon Island between 12° and 17°N, and the southernmost end of the SCS basin. They are primarily caused by strong interference, noncircular eddy shapes, and gentle sea level anomaly (SLA) gradients, respectively. The SLA, winding angle, and hybrid methods can easily detect the mesoscale eddies with wavelike features. The Okubo–Weiss (OW) and the spatially smoothed OW methods better identify grouping phenomena of mesoscale eddies in the SCS. Suggestions are presented on choosing suitable algorithms for studying mesoscale eddies in the SCS. No single algorithm is perfect for all research purposes. For different studies, the most suitable algorithm is different.

© 2019 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: Zexun Wei, weizx@fio.org.cn

Abstract

Numerous oceanic mesoscale eddies occur in the South China Sea (SCS). The present study employs eight automatic eddy detection algorithms to identify these mesoscale eddies and compares the results. Eddy probabilities and areas detected by various algorithms differ substantially. Most regions of the SCS with a high discrepancy of eddy probabilities are those with few mesoscale eddies, except for the area west of the Luzon Strait, the area west of Luzon Island between 12° and 17°N, and the southernmost end of the SCS basin. They are primarily caused by strong interference, noncircular eddy shapes, and gentle sea level anomaly (SLA) gradients, respectively. The SLA, winding angle, and hybrid methods can easily detect the mesoscale eddies with wavelike features. The Okubo–Weiss (OW) and the spatially smoothed OW methods better identify grouping phenomena of mesoscale eddies in the SCS. Suggestions are presented on choosing suitable algorithms for studying mesoscale eddies in the SCS. No single algorithm is perfect for all research purposes. For different studies, the most suitable algorithm is different.

© 2019 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: Zexun Wei, weizx@fio.org.cn
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  • Chaigneau, A., A. Gizolme, and C. Grados, 2008: Mesoscale eddies off Peru in altimeter records: Identification algorithms and eddy spatio-temporal patterns. Prog. Oceanogr., 79, 106119, https://doi.org/10.1016/j.pocean.2008.10.013.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chaigneau, A., G. Eldin, and B. Dewitte, 2009: Eddy activity in the four major upwelling systems from satellite altimetry (1992–2007). Prog. Oceanogr., 83, 117123, https://doi.org/10.1016/j.pocean.2009.07.012.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chelton, D. B., R. A. de Szoeke, M. G. Schlax, K. El Naggar, and N. Siwertz, 1998: Geographical variability of the first baroclinic Rossby radius of deformation. J. Phys. Oceanogr., 28, 433460, https://doi.org/10.1175/1520-0485(1998)028<0433:GVOTFB>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chelton, D. B., M. G. Schlax, and R. M. Samelson, 2011: Global observations of nonlinear mesoscale eddies. Prog. Oceanogr., 91, 167216, https://doi.org/10.1016/j.pocean.2011.01.002.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chen, G., Y. Hou, and X. Chu, 2011: Mesoscale eddies in the South China Sea: Mean properties, spatiotemporal variability, and impact on thermohaline structure. J. Geophys. Res., 116, C06018, https://doi.org/10.1029/2010JC006716.

    • Search Google Scholar
    • Export Citation
  • Chen, G., J. Gan, Q. Xie, X. Chu, D. Wang, and Y. Hou, 2012: Eddy heat and salt transports in the South China Sea and their seasonal modulations. J. Geophys. Res., 117, C05021, https://doi.org/10.1029/2011JC007724.

    • Search Google Scholar
    • Export Citation
  • Chen, G., and Coauthors, 2015: Observed deep energetic eddies by seamount wake. Sci. Rep., 5, 17416, https://doi.org/10.1038/srep17416.

  • Chu, X., H. Xue, Y. Qi, G. Chen, Q. Mao, D. Wang, and F. Chai, 2014: An exceptional anticyclonic eddy in the South China Sea in 2010. J. Geophys. Res. Oceans, 119, 881897, https://doi.org/10.1002/2013JC009314.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Doglioli, A. M., B. Blanke, S. Speich, and G. Lapeyre, 2007: Tracking coherent structures in a regional ocean model with wavelet analysis: Application to Cape Basin eddies. J. Geophys. Res., 112, C05043, https://doi.org/10.1029/2006JC003952.

    • Search Google Scholar
    • Export Citation
  • Geng, W., Q. Xie, G. Chen, T. Zu, and D. Wang, 2016: Numerical study on the eddy–mean flow interaction between a cyclonic eddy and Kuroshio. J. Oceanogr., 72, 727745, https://doi.org/10.1007/s10872-016-0366-0.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Geng, W., Q. Xie, G. Chen, Q. Liu, and D. Wang, 2018: A three-dimensional modeling study on eddy-mean flow interaction between a Gaussian-type anticyclonic eddy and Kuroshio. J. Oceanogr., 74, 2337, https://doi.org/10.1007/s10872-017-0435-z.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Guo, M., F. Chai, P. Xiu, S. Li, and S. Rao, 2015: Impacts of mesoscale eddies in the South China Sea on biogeochemical cycles. Ocean Dyn., 65, 13351352, https://doi.org/10.1007/s10236-015-0867-1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Henson, S. A., and A. C. Thomas, 2008: A census of oceanic anticyclonic eddies in the Gulf of Alaska. Deep-Sea Res. I, 55, 163176, https://doi.org/10.1016/j.dsr.2007.11.005.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hu, J., Z. Gan, J. Zhu, and M. Dai, 2011: Observed three dimensional structure of a cold eddy in the southwestern South China Sea. J. Geophys. Res., 116, C05016, https://doi.org/10.1029/2010JC006810.

    • Search Google Scholar
    • Export Citation
  • Li, L., W. D. Nowlin, and S. Jilan, 1998: Anticyclonic rings from the Kuroshio in the South China Sea. Deep-Sea Res. I, 45, 14691482, https://doi.org/10.1016/S0967-0637(98)00026-0.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lin, X., C. Dong, D. Chen, Y. Liu, J. Yang, B. Zou, and Y. Guan, 2015: Three-dimensional properties of mesoscale eddies in the South China Sea based on eddy-resolving model output. Deep-Sea Res. I, 99, 4664, https://doi.org/10.1016/j.dsr.2015.01.007.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Nan, F., Z. He, H. Zhou, and D. Wang, 2011a: Three long-lived anticyclonic eddies in the northern South China Sea. J. Geophys. Res., 116, C05002, https://doi.org/10.1029/2010JC006790.

    • Search Google Scholar
    • Export Citation
  • Nan, F., H. Xue, P. Xiu, F. Chai, M. Shi, and P. Guo, 2011b: Oceanic eddy formation and propagation southwest of Taiwan. J. Geophys. Res., 116, C12045, https://doi.org/10.1029/2011JC007386.

    • Search Google Scholar
    • Export Citation
  • Nan, F., H. Xue, and F. Yu, 2015: Kuroshio intrusion into the South China Sea: A review. Prog. Oceanogr., 137, 314333, https://doi.org/10.1016/j.pocean.2014.05.012.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Nencioli, F., C. Dong, T. Dickey, L. Washburn, and J. McWilliams, 2010: A vector geometry–based eddy detection algorithm and its application to a high-resolution numerical model product and high-frequency radar surface velocities in the Southern California Bight. J. Atmos. Oceanic Technol., 27, 564579, https://doi.org/10.1175/2009JTECHO725.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Petersen, M. R., S. J. Williams, M. E. Maltrud, M. W. Hecht, and B. Hamann, 2013: A three-dimensional eddy census of a high-resolution global ocean simulation. J. Geophys. Res. Oceans, 118, 17591774, https://doi.org/10.1002/jgrc.20155.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sadarjoen, I. A., and F. H. Post, 2000: Detection, quantification, and tracking of vortices using streamline geometry. Comput. Graphics, 24, 333341, https://doi.org/10.1016/S0097-8493(00)00029-7.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sheu, W.-J., C.-R. Wu, and L.-Y. Oey, 2010: Blocking and westward passage of eddies in the Luzon Strait. Deep-Sea Res. II, 57, 17831791, https://doi.org/10.1016/j.dsr2.2010.04.004.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Souza, J. M. A. C., C. Montégut, and P. Y. Traon, 2011: Comparison between three implementations of automatic identification algorithms for the quantification and characterization of mesoscale eddies in the South Atlantic Ocean. Ocean Sci., 7, 317334, https://doi.org/10.5194/os-7-317-2011.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, D., H. Xu, J. Lin, and J. Hu, 2008: Anticyclonic eddies in the northeastern South China Sea during winter 2003/2004. J. Oceanogr., 64, 925935, https://doi.org/10.1007/s10872-008-0076-3.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, G., J. Su, and P. C. Chu, 2003: Mesoscale eddies in the South China Sea observed with altimeter data. Geophys. Res. Lett., 30, 2121, https://doi.org/10.1029/2003GL018532.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, Q., L. Zeng, W. Zhou, Q. Xie, S. Cai, J. Yao, and D. Wang, 2015: Mesoscale eddies cases study at Xisha waters in the South China Sea in 2009/2010. J. Geophys. Res. Oceans, 120, 517532, https://doi.org/10.1002/2014JC009814.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Williams, S., M. Petersen, P. T. Bremer, M. Hecht, V. Pascucci, J. Ahrens, M. Hlawitschka, and B. Hamann, 2011: Adaptive extraction and quantification of geophysical vortices. IEEE Trans. Visualization Comput. Graphics, 17, 20882095, https://doi.org/10.1109/TVCG.2011.162.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xie, L., and Q. Zheng, 2017: New insight into the South China Sea: Rossby normal modes. Acta Oceanol. Sin., 36, 13, https://doi.org/10.1007/s13131-017-1077-0.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xiu, P., F. Chai, L. Shi, H. Xue, and Y. Chao, 2010: A census of eddy activities in the South China Sea during 1993–2007. J. Geophys. Res., 115, C03012, https://doi.org/10.1029/2009JC005657.

    • Search Google Scholar
    • Export Citation
  • Yi, J., Y. Du, Z. He, and C. Zhou, 2014: Enhancing the accuracy of automatic eddy detection and the capability of recognizing the multi-core structures from maps of sea level anomaly. Ocean Sci., 10, 3948, https://doi.org/10.5194/os-10-39-2014.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yuan, D., W. Han, and D. Hu, 2007: Anti-cyclonic eddies northwest of Luzon in summer–fall observed by satellite altimeters. Geophys. Res. Lett., 34, L13610, https://doi.org/10.1029/2007GL029401.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zhang, Y., Z. Liu, Y. Zhao, W. Wang, J. Li, and J. Xu, 2014: Mesoscale eddies transport deep-sea sediments. Sci. Rep., 4, 5937, https://doi.org/10.1038/srep05937.

    • Search Google Scholar
    • Export Citation
  • Zhang, Z., W. Zhao, J. Tian, and X. Liang, 2013: A mesoscale eddy pair southwest of Taiwan and its influence on deep circulation. J. Geophys. Res. Oceans, 118, 64796494, https://doi.org/10.1002/2013JC008994.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zhang, Z., J. Tian, B. Qiu, W. Zhao, P. Chang, D. Wu, and X. Wan, 2016: Observed 3D structure, generation, and dissipation of oceanic mesoscale eddies in the South China Sea. Sci. Rep., 6, 24349, https://doi.org/10.1038/srep24349.

    • Search Google Scholar
    • Export Citation
  • Zhang, Z., W. Zhao, B. Qiu, and J. Tian, 2017: Anticyclonic eddy sheddings from Kuroshio loop and the accompanying cyclonic eddy in the northeastern South China Sea. J. Phys. Oceanogr., 47, 12431259, https://doi.org/10.1175/JPO-D-16-0185.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zu, T., D. Wang, C. Yan, I. Belkin, W. Zhuang, and J. Chen, 2013: Evolution of an anticyclonic eddy southwest of Taiwan. Ocean Dyn., 63, 519531, https://doi.org/10.1007/s10236-013-0612-6.

    • Crossref
    • Search Google Scholar
    • Export Citation
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