Deep water in the South China Sea is renewed by the cold and dense Luzon Strait overflow. However, from where and how the deep water upwells is poorly understood yet. Based on the Hybrid Coordinate Ocean Model reanalysis data, vertical velocity is derived to answer these questions. Domain-integrated vertical velocity is of two maxima, one in the shallow water and the other at depth, and separated by a layer of minimum at the bottom of the thermocline. Further analysis shows that this two-segmented vertical transport is attributed to the vertical compensation of subsurface water to the excessive outflow of shallow water and upward push of the dense Luzon Strait overflow, respectively. In the abyssal basin, the vertical transport increases upward from zero at the depth of 3500–4000 m and reaches a maximum of 1.5×106 m3/s at about 1500 m. Deep water upwells mainly from the northeastern and southwestern ends of the abyssal basin and off the continental slopes. To explain the upward velocity arising from slope breaks, a possible mechanism is proposed that an onshore velocity component can be derived from the deep western boundary current above steep slopes under bottom friction.

Yaohua Zhu;Dingqi Wang;Yonggang Wang;Shujiang Li;Tengfei Xu;Zexun Wei

First Institute of Oceanography,and Key Laboratory of Marine Science and Numerical Modeling,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;Shandong Key Laboratory of Marine Science and Numerical Modeling,Qingdao 266061,China;College of Oceanic and Atmospheric Sciences,Ocean University of China,Qingdao 266100,China

海洋学报（英文版）

[1]Yaohua Zhu;Dingqi Wang;Yonggang Wang;Shujiang Li;Tengfei Xu;Zexun Wei-.Vertical velocity and transport in the South China Sea)[J].海洋学报（英文版）,2022(07):13-25

upwells

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