Haiyuan Yang, Ruichen Zhu, Zhaohui Chen, Jianchao Li, Lixin Wu

Published in Journal of Geophysical Research: Oceans, November 2022

Abstract

Based on observations and eddy-resolving model products, this study investigates the temperature variability south of the Oyashio Extension (OE). During 2016–2021, six dramatic cold events, which significantly impact the local ecosystems, are captured by in situ and satellite observations. It reveals that interaction between the OE front (OEF) and anticyclonic mesoscale eddies originating from the Kuroshio Extension is responsible for these cold events. Accompanied by intense eddy-flow baroclinic energy exchange, the OEF meanders to the south and favors a southward cold-water intrusion. Further analysis illustrates that the cold events tend to occur during spring and autumn, which is associated with the seasonal evolutions of OEF and anticyclonic eddies.

Key Points

• Temperature plummet and zooplankton increase are captured by a subsurface mooring to the south of Oyashio Extension
• The development of Oyashio Extension front meander and its interaction with eddies account for the temperature variability
• The eddy-flow interaction is characterized by strong baroclinic energy exchange

Fig. (a) Mean sea surface height (SSH) field (Unit: m; white contours) surrounding the Kuroshio and Oyashio Extension region from 2016 to 2021. The thick white line denotes the contour of 0.3 m and the contour interval is 0.1 m. Color shading indicates the magnitude of the horizontal sea surface temperature (SST) gradient during the same period. The red pentagram denotes the location of M2 mooring. (b) Schematic of the design of M2.

Yang, H., Zhu, R., Chen, Z., Li, J., & Wu, L. (2022). Temperature variability and eddy-flow interaction in the south of Oyashio Extension. Journal of Geophysical Research: Oceans, 127, e2022JC019051. https://doi.org/10.1029/2022JC019051