Journal of Tropical Oceanography ›› 2023, Vol. 42 ›› Issue (3): 75-85.doi: 10.11978/2022152CSTR: 32234.14.2022152

• Marine Hydrology • Previous Articles     Next Articles

Spatiotemporal characteristics of mesoscale eddies with transport capability of saline Kuroshio water in the northern South China Sea

YANG Yikai1(), ZENG Lili1,2()   

  1. 1. State Key Laboratory of Tropical Oceanography (South China Sea Institute of Oceanology, Chinese Academy of Sciences), Guangzhou 510301, China
    2. Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
  • Received:2022-07-05 Revised:2022-09-14 Online:2023-05-10 Published:2022-09-28
  • Supported by:
    Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou)(GML2019ZD0306); National Natural Science Foundation of China(41676018); Science and Technology Planning Project of Guangzhou City, China(202002030490)

Abstract:

Eddy-induced transport in the Luzon Strait significantly affects the thermo-salt balance in the northern South China Sea. Using the AVISO satellite data from 1993 to 2018, this paper identifies and screens 76 Kuroshio shedding anticyclic eddies, 46 Kuroshio associated cyclonic eddies, 29 South China Sea (SCS) locally-formed anticyclic eddies and 40 SCS locally-formed cyclonic eddies in the northern SCS. The average nonlinear coefficients of the four types of eddies are all much larger than 1, which confirms that the screening eddies do have the capacity of transporting the saline Kuroshio water. The propagation paths of the eddy are affected by the topography of the northern SCS, and shift to the southwest during the westward propagation process. Compared with the cyclonic eddy, the anticyclonic eddy moved farther to the northern part of the SCS. The eddies are mostly formed in the middle of the Luzon Strait, and the probability of formation gradually decreases with the increase or decrease of latitude. The shedding (associated) eddies are mostly formed in autumn and winter and the least in summer and the average number of anticyclonic eddies is 2.5 more than cyclonic eddies per month. The annual average number of shedding (associated) eddies is about 4.6, and cyclonic eddies do not form every year. Overall, the El Niño event increases the number of Kuroshio shedding or associated eddies by affecting the Kuroshio path.

Key words: northern South China Sea, Kuroshio, saline water, mesoscale eddy