ENSO‐Related Interannual Variability of the Kuroshio in the East China Sea Since the Mid‐2000s

Abstract

Using observational and reanalysis data sets, we investigated interannual variability in the Kuroshio in the East China Sea (ECS‐Kuroshio). We exhibited that the surface velocity and position of the ECS‐Kuroshio were synchronized on a quasi‐3‐year interannual timescale during 2005–2016. We further demonstrated that: (a) during 2005–2016, wind stress curl variability related to the El Niño–Southern Oscillation (ENSO) played a leading role in the interannual ECS‐Kuroshio variability by exciting baroclinic Rossby waves along the subtropical countercurrent (STCC) zone east of Taiwan; (b) mesoscale eddy activities in the STCC zone, especially long‐lived (≥150‐day lifetime) cyclonic eddies, probably played a secondary role in the interannual ECS‐Kuroshio variability. In addition, we showed that the occurrence of the quasi‐3‐year interannual variability of the ECS‐Kuroshio since 2005 was likely linked to the following changes in the ENSO‐related atmospheric circulation: (a) The primary ENSO timescale changed from a quasi‐5‐year period in 1993–2004 to a quasi‐3‐year one in 2005–2016; (b) Over the central equatorial Pacific along with the eastern tropical Indian Ocean, the sea surface temperature in 2005–2016 varied with a more intense amplitude than in 1993–2004, which resulted in a different western North Pacific atmospheric response to the ENSO in 2005–2016 from that in 1993–2004.

Decadal Variation in Winter‐Spring Thermal Front to the Zhejiang‐Fujian Coast and Its Mechanism

“…Moreover, the upstream Kuroshio strength calculated by all three data sets showed a significant negative trend (P < 0.01), further supporting the intrusion mode. Notably, variability of the upstream Kuroshio strength can be modulated by the eddy activities in the STCC zone and the North Pacific wind stress curls which were closely associated with the ENSO and PDO (Qiao et al, 2023;Wang et al, 2023;Wu et al, 2014).…”