Characteristics and temporal variations of near-bottom currents near the Dongsha Island in the northern South China Sea

Li Dawei; Wei Zexun; Wang Yonggang; Li Shujiang; Xu Tengfei; Wang Guanlin; Teng Fei

doi:10.1007/s13131-019-1415-5

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Article Navigation > Acta Oceanologica Sinica > 2019 > 38(4): 80-89

Li Dawei, Wei Zexun, Wang Yonggang, Li Shujiang, Xu Tengfei, Wang Guanlin, Teng Fei. Characteristics and temporal variations of near-bottom currents near the Dongsha Island in the northern South China Sea[J]. Acta Oceanologica Sinica, 2019, 38(4): 80-89. doi: 10.1007/s13131-019-1415-5

Citation:

Li Dawei, Wei Zexun, Wang Yonggang, Li Shujiang, Xu Tengfei, Wang Guanlin, Teng Fei. Characteristics and temporal variations of near-bottom currents near the Dongsha Island in the northern South China Sea[J]. Acta Oceanologica Sinica, 2019, 38(4): 80-89. doi: 10.1007/s13131-019-1415-5

Citation:

Li Dawei, Wei Zexun, Wang Yonggang, Li Shujiang, Xu Tengfei, Wang Guanlin, Teng Fei. Characteristics and temporal variations of near-bottom currents near the Dongsha Island in the northern South China Sea[J]. Acta Oceanologica Sinica, 2019, 38(4): 80-89. doi: 10.1007/s13131-019-1415-5

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Characteristics and temporal variations of near-bottom currents near the Dongsha Island in the northern South China Sea

doi: 10.1007/s13131-019-1415-5

Key Laboratory of Marine Science and Numerical Modeling, First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China;Laboratory for Regional Oceanography and Numerical Modeling, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China

Received Date: 2018-06-20

Abstract

Abstract

Near-bottom currents play important roles in the formation and dynamics of deep-water sedimentary systems. This study examined the characteristics and temporal variations of near-bottom currents, especially the tidal components, based on two campaigns (2014 and 2016) of in situ observations conducted southeast of the Dongsha Island in the South China Sea. Results demonstrated near-bottom currents are dominated by tidal currents, the variance of which could account for~70% of the total current variance. Diurnal tidal currents were found stronger than semidiurnal currents for both barotropic and baroclinic components. The diurnal tidal currents were found polarized with predominantly clockwise-rotating constituents, whereas the clockwise and counterclockwise constituents were found comparable for semidiurnal tidal currents. It was established that diurnal tidal currents could induce strong current shear. Baroclinic tidal currents showed pronounced seasonal variation with large magnitude in winter and summer and weak magnitude in spring and autumn in 2014. The coherent components accounted for~65% and~50% of the diurnal and semidiurnal tidal current variances, respectively. The proportions of the coherent and incoherent components changed little in different seasons. In addition to tidal currents, it was determined that the passing of mesoscale eddies could induce strong near-bottom currents that have considerable influence on the deep circulation.
- tidal currents,
- South China Sea,
- near-bottom currents,
- mesoscale eddies

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References(29)

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