ORIGINAL RESEARCH article
Front. Mar. Sci.
Sec. Physical Oceanography
Volume 12 - 2025 | doi: 10.3389/fmars.2025.1675413
Atypical seasonal variability of the Kuroshio Current in 2018
Provisionally accepted
- Institute of Oceanology, Chinese Academy of Sciences (CAS), Qingdao, China
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Using three moorings deployed at 122.7°E, 123°E, and 123.3°E along 18°N from January 2018 to May 2020, this study investigates the seasonal variability of the Kuroshio Current (KC). In 2019, the KC was relatively strong during spring, summer, and winter, with the weakest flow occurring in autumn, consistent with climatological seasonal cycles. In contrast, the KC displayed an atypical seasonal cycle in 2018, which was manifested as two distinct intraseasonal intensification events in late September and early November. As a wind-driven current, the KC's variability is closely linked to local wind and Rossby waves. Sensitive experiments conducted with the Regional Ocean Modeling System revealed that local winds within the region 120°E–125°E, 15°N–20°N were the primary driver of the atypical seasonal cycle observed in 2018. During two key periods (22 September to 1 October and 31 October to 9 November), the wind stress curl anomaly east of the mooring stations remained predominantly negative (except on 1 October). This anomaly induced integrated positive sea surface height anomalies and corresponding northward meridional velocity anomalies via geostrophic balance. In 2019, the wind stress curl anomaly phases reversed compared to 2018, leading to the absence of the two peaks observed in the previous year.
Keywords: Kuroshio Current, seasonal variability, Local wind, Rossby waves, Mooring observation
Received: 29 Jul 2025; Accepted: 20 Oct 2025.
Copyright: © 2025 Wang, Zhang, Feng, Wang and Hu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Fujun Wang, fujunwang@qdio.ac.cn
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