Increasing deep-water overflow from the Pacific into the South China Sea revealed by mooring observations

Chun Zhou; Xin Xiao; Wei Zhao; Jiayan Yang; Xiaodong Huang; Shoude Guan; Zhiwei Zhang; Jiwei Tian

doi:10.1038/s41467-023-37767-4

Increasing deep-water overflow from the Pacific into the South China Sea revealed by mooring observations

Nat Commun. 2023 Apr 10;14(1):2013. doi: 10.1038/s41467-023-37767-4.

Authors

Chun Zhou^#^{1

2}, Xin Xiao^#¹, Wei Zhao^{3

4}, Jiayan Yang⁵, Xiaodong Huang^{1

2}, Shoude Guan^{1

2}, Zhiwei Zhang^{1

2}, Jiwei Tian^{6

7}

Affiliations

¹ Frontier Science Center for Deep Ocean Multispheres and Earth System (FDOMES) and Physical Oceanography Laboratory, Key Laboratory of Ocean Observation and Information of Hainan Province/Sanya Oceanographic Institution, Ocean University of China, Qingdao/Sanya, China.
² Laoshan Laboratory, Qingdao, China.
³ Frontier Science Center for Deep Ocean Multispheres and Earth System (FDOMES) and Physical Oceanography Laboratory, Key Laboratory of Ocean Observation and Information of Hainan Province/Sanya Oceanographic Institution, Ocean University of China, Qingdao/Sanya, China. weizhao@ouc.edu.cn.
⁴ Laoshan Laboratory, Qingdao, China. weizhao@ouc.edu.cn.
⁵ Woods Hole Oceanographic Institution, Woods Hole, 02543, MA, USA.
⁶ Frontier Science Center for Deep Ocean Multispheres and Earth System (FDOMES) and Physical Oceanography Laboratory, Key Laboratory of Ocean Observation and Information of Hainan Province/Sanya Oceanographic Institution, Ocean University of China, Qingdao/Sanya, China. tianjw@ouc.edu.cn.
⁷ Laoshan Laboratory, Qingdao, China. tianjw@ouc.edu.cn.

^# Contributed equally.

Abstract

Cold and dense water from the North Pacific Ocean that spills through the Luzon Strait, the only deep conduit between the South China Sea (SCS) and the Pacific Ocean, renews deep-water mass, modulates hydrographic and biogeochemical cycles, and drives abyssal and overturning circulations in the SCS. The variability of this key oceanic process, however, has been poorly studied, mainly due to a lack of sustained observations. A comprehensive observational program that started in 2009 has provided 12 years of continuous time series of velocity and volume transport within the Luzon Strait. Here we show the observation-based assessment of decadal trends of deep-water transport through this vital passage. With the estimated 12-year mean volume transport of the deep-water overflow into the SCS of 0.84 ± 0.39 Sv (1 Sv = 10⁶ m³ s^-1), a significant linear upward trend of 9% is revealed during this period. This is consistent with long-term changes in satellite-observed ocean bottom pressure. The results of this study may have broad implications for the overturning circulations and biogeochemical processes, including carbon cycles in this region.

Abstract

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