Increased tropical South Pacific western boundary current transport over the past century

Wen Hui Chen*, Haojia Ren*, John C.H. Chiang, You Lin Wang, Ren Yi Cai-Li, Yi Chi Chen, Chuan Chou Shen, Frederick W. Taylor, Thomas M. DeCarlo, Chau Ron Wu, Horng Sheng Mii, Xingchen Tony Wang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


The wind-driven meridional overturning circulation between the tropical and subtropical oceans is important for regulating decadal-scale temperature fluctuations in the Pacific Ocean and globally. An acceleration of the overturning circulation can act to reduce global surface temperature as ocean stores more heat. The equatorward low-latitude western boundary current represents a key component of the meridional circulation cell in the Pacific and a major source of water mass for the Equatorial Undercurrent, yet long-term observations of its transport are scarce. Here we demonstrate that the 15N/14N ratio recorded by Porites spp. corals in the western tropical South Pacific is sensitive to the exchanges of water masses driven by the western boundary transport. Using a 94-year coral record from the Solomon Sea, we report that the 15N/14N ratio declined as the global surface temperature rose. The record suggests that the South Pacific western boundary current has strengthened in the past century, and it may have contributed to the reported strengthening of the Equatorial Undercurrent. In addition, the 15N/14N record shows strong decadal variability, indicative of weaker equatorial Pacific upwelling and stronger western boundary transport when the eastern equatorial Pacific is in the warm stage of the Pacific Decadal Oscillation.

Original languageEnglish
Pages (from-to)590-596
Number of pages7
JournalNature Geoscience
Issue number7
Publication statusPublished - 2023 Jul

ASJC Scopus subject areas

  • General Earth and Planetary Sciences


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