Abstract
The continental slope in the northern South China Sea (SCS) is rich in mesoscale eddies which play an important role in transport and retention of nutrients and biota. In this study, we investigate the statistical properties of eddy distributions and propagation in a period of 24 years between 1993 and 2016 by using the altimeter data. A total of 147 eddies are found in the continental slope region (CSR), including 70 cyclonic eddies (CEs) and 77 anticyclonic eddies (ACEs). For those eddies that appear in the CSR, the surrounding areas of Dongsha Islands (DS) and southwest of Taiwan (SWT) are considered as the primary sources, where eddies generated contribute more than 60% of the total. According to the spatial distribution of eddy relative vorticity, eddies are weakening as propagating westward. Although both CEs and ACEs roughly propagate along the slope isobaths, there are discrepancies between CEs and ACEs. The ACEs move slightly faster in the zonal direction, while the CEs tend to cross the isobaths with large bottom depth change. The ACEs generally move further into the basin areas after leaving the CSR while CEs remain around the CSR. The eddy propagation on the continental slope is likely to be associated with mean flow at a certain degree because the eddy trajectories have notable seasonal signals that are consistent with the seasonal cycle of geostrophic current. The results indicate that the eddy translation speed is statistically consistent with geostrophic velocity in both magnitude and direction.
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References
Chelton D B, Schlax M G, Samelson R M, et al. 2007. Global observations of large oceanic eddies. Geophysical Research Letters, 34(15): L15606
Chelton D B, Schlax M G, Samelson R M. 2011. Global observations of nonlinear mesoscale eddies. Progress in Oceanography, 91(2): 167–216, doi: https://doi.org/10.1016/j.pocean.2011.01.002
Chen Gengxin, Hou Yijun, Chu Xiaoqing. 2011. Mesoscale eddies in the South China Sea: Mean properties, spatiotemporal variability, and impact on thermohaline structure. Journal of Geophysical Research, 116(C6): C06018
Chen Zhongwei, Yang Chenghao, Xu Dongfeng, et al. 2016. Observed hydrographical features and circulation with influences of cyclonic-anticyclonic eddy-pair in the northern slope of the South China Sea during June 2015. Journal of Marine Sciences (in Chinese), 34(4): 10–19
Chow C H, Hu J H, Centurioni L R, et al. 2008. Mesoscale Dongsha Cyclonic Eddy in the northern South China Sea by drifter and satellite observations. Journal of Geophysical Research: Oceans, 113(C4): C04018
Cushman-Roisin B, Tang B, Chassignet E P. 1990. Westward motion of mesoscale eddies. Journal of Physical Oceanography, 20(5): 758–768, doi: https://doi.org/10.1175/1520-0485(1990)020<0758:WMOME>2.0.CO;2
Dong Changming. 2015. Oceanic Eddy Detection and Analysis (in Chinese). Beijing: Science Press
He Xianqiang, Xu Dongfeng, Bai Yan, et al. 2016. Eddy-entrained Pearl River plume into the oligotrophic basin of the South China Sea. Continental Shelf Research, 124: 117–124, doi: https://doi.org/10.1016/j.csr.2016.06.003
Hu Jianyu, Kawamura H, Hong Huasheng, et al. 2000. A review on the currents in the South China Sea: Seasonal Circulation, South China Sea warm current and Kuroshio intrusion. Journal of Oceanography, 56(6): 607–624, doi: https://doi.org/10.1023/A:1011117531252
Hu Jianyu, Gan Jianping, Sun Zhenyu, et al. 2011. Observed three-dimensional structure of a cold eddy in the southwestern South China Sea. Journal of Geophysical Research: Oceans, 116(C5): C05016
Huang Xiaodong, Zhang Zhiwei, Zhang Xiaojiang. 2017a. Impacts of a mesoscale eddy pair on internal solitary waves in the Northern South China Sea revealed by mooring array observations. Journal of Physical Oceanography, 47(7): 1539–1554, doi: https://doi.org/10.1175/JPO-D-16-0111.1
Huang Xiaorong, Wang Qiang, Zhou Weidong. 2017b. Model diagnostic analysis of cross-shelf flow in the northern South China Sea. Chinese Science Bulletin, 62(10): 1059–1070, doi: https://doi.org/10.1360/N972016-00570
Jacob J P, Chassignet E P, Dewar W K. 2002. Influence of topography on the propagation of isolated eddies. Journal of Physical Oceanography, 32(10): 2848–2869, doi: https://doi.org/10.1175/1520-0485(2002)032<2848:IOTOTP>2.0.CO;2
Liu Qinyu, Jiang Xia, Xie Shangping, et al. 2004. A gap in the Indo-Pacific warm pool over the South China Sea in boreal winter: Seasonal development and interannual variability. Journal of Geophysical Research: Oceans, 109(C7): C07012
Luan Xiwu, Zhang Liang, Yue Baojing. 2010. Influence on gas hydrates formation produced by volcanic activity on northern South China Sea slope. Geoscience (in Chinese), 24(3): 424–432
Morrow R, Birol F, Griffin D, et al. 2004. Divergent pathways of cyclonic and anti-cyclonic ocean eddies. Geophysical Research Letters, 31(24): L24311, doi: https://doi.org/10.1029/2004GL020974
Nan Feng, Xue Huijie, Xiu Peng, et al. 2011a. Oceanic eddy formation and propagation southwest of Taiwan. Journal of Geophysical Research: Oceans, 116(C12): C12045, doi: https://doi.org/10.1029/2011JC007386
Nan Feng, Xue Huijie, Chai Fei, et al. 2011b. Identification of different types of Kuroshio intrusion into the South China Sea. Ocean Dynamics, 61(9): 1291–1304, doi: https://doi.org/10.1007/s10236-011-0426-3
Nencioli F, Dong Changming, Dickey T, et al. 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. Journal of Atmospheric and Oceanic Technology, 27(3): 564–579, doi: https://doi.org/10.1175/2009JTECHO725.1
Oey L Y, Zhang H C. 2004. The generation of subsurface cyclones and jets through eddy-slope interaction. Continental Shelf Research, 24(18): 2109–2131, doi: https://doi.org/10.1016/j.csr.2004.07.007
Peliz A, Santos M P, Oliveira P B, et al. 2004. Extreme cross-shelf transport induced by eddy interactions southwest of Iberia in winter 2001. Geophysical Research Letters, 31(8): L08301
Su Jilan. 2004. Overview of the South China Sea circulation and its influence on the coastal physical oceanography outside the Pearl River Estuary. Continental Shelf Research, 24(16): 1745–1760, doi: https://doi.org/10.1016/j.csr.2004.06.005
Wang Dongxiao, Wang Qiang, Zhou Weidong, et al. 2013. An analysis of the current deflection around Dongsha Islands in the northern South China Sea. Journal of Geophysical Research: Oceans, 118(1): 490–501, doi: https://doi.org/10.1029/2012JC008429
Wang Dingqi, Fang Guohong, Qiu Ting. 2017. The characteristics of eddies shedding from Kuroshio in the Luzon Strait. Oceanologia et Limnologia Sinica (in Chinese), 48(4): 672–681
Washburn L, Swenson M S, Largier J L, et al. 1993. Cross-shelf sediment transport by an anticyclonic eddy off northern California. Science, 261(5128): 1560–1564, doi: https://doi.org/10.1126/science.261.5128.1560
Xiu Peng, Chai Fei, Shi Lei, et al. 2010. A census of eddy activities in the South China Sea during 1993–2007. Journal of Geophysical Research: Oceans, 115(C3): C03012
Xue Huijie, Chai Fei, Pettigrew N, et al. 2004. Kuroshio intrusion and the circulation in the South China Sea. Journal of Geophysical Research: Oceans, 109(C2): C02017
Yuan Dongliang, Han Weiqing, Hu Dunxin. 2007. Anti-cyclonic eddies northwest of Luzon in summer-fall observed by satellite altimeters. Geophysical Research Letters, 34(13): L13610
Yuan Meng, Chen Zuozhi, Zhang Jun, et al. 2018. Community structure of mesopelagic fish species in northern slope of South China Sea. South China Fisheries Science (in Chinese), 14(1): 85–91
Zhai Xiaoming, Greatbatch R J, Kohlmann J D. 2008. On the seasonal variability of eddy kinetic energy in the Gulf Stream region. Geophysical Research Letters, 35(24): L24609, doi: https://doi.org/10.1029/2008GL036412
Zhang Zhiwei, Zhao Wei, Tian Jiwei, et al. 2013. A mesoscale eddy pair southwest of Taiwan and its influence on deep circulation. Journal of Geophysical Research: Oceans, 118(12): 6479–6494, doi: https://doi.org/10.1002/2013JC008994
Zhang Zhengguang, Wang Wei, Qiu Bo. 2014. Oceanic mass transport by mesoscale eddies. Science, 345(6194): 318–322, doi: https://doi.org/10.1126/science.1249770
Zhang Zhiwei, Zhao Wei, Qiu Bo, et al. 2017. Anticyclonic eddy sheddings from kuroshio loop and the accompanying cyclonic eddy in the northeastern South China Sea. Journal of Physical Oceanography, 47(6): 1243–1259, doi: https://doi.org/10.1175/JPO-D-16-0185.1
Zheng Quanan, Xie Lingling, Zheng Zhiwen, et al. 2017. Progress in research of mesoscale eddies in the South China Sea. Advances in Marine Science (in Chinese), 35(2): 131–158
Acknowledgements
The altimeter data is provided by E.U. Copernicus Marine Service Information. We also appreciate the eddy detection method provided by Changming Dong from Nanjing University of Information Science & Technology.
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Foundation item: The National Basic Research Program of China under contract Nos 2014CB441500 and 2014CB441506, the National Natural Science Fundation of China under contract No. 41706014; the Shanghai Jiao Tong University Fund under contract No. 2019 SJTU-HKUST.
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Cheng, Z., Zhou, M., Zhong, Y. et al. Statistical characteristics of mesoscale eddies on the continental slope in the northern South China Sea. Acta Oceanol. Sin. 39, 36–44 (2020). https://doi.org/10.1007/s13131-019-1530-3
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DOI: https://doi.org/10.1007/s13131-019-1530-3