The pattern and variability of winter Kuroshio intrusion northeast of Taiwan

Abstract

The variations of the Kuroshio path and velocity northeast of Taiwan are analyzed based on along-track satellite altimeter data as well as high-resolution model experiments. Observations reveal that in winter the Kuroshio intrusion into the East China Sea (ECS) at this location is manifested by a secondary maximum current core (SMCC) shoreward of the Kuroshio's main path. The SMCC varies significantly on interannual time scale, and its variability is strikingly out of phase with that of the Kuroshio entering the ECS, meaning that the stronger the Kuroshio, the weaker the SMCC, and vice versa. Model experiments corroborate the observational results and, more importantly, indicate that the Kuroshio intrusion here follows two primary routes, a large anticyclonic loop that separates from the Kuroshio at the northern end of Taiwan and moves forward to form the SMCC, and a straight northward path onto the shelf when the Kuroshio turns sharply eastward along the continental slope of the ECS. The intrusion is controlled by both local forcing and remote effect, with its pattern and variability depending mostly on the local heat flux and the inertia of the Kuroshio Current.

Impacts of the IOD-associated temperature and salinity anomalies on the intermittent equatorial undercurrent anomalies

“…It solves the primitive equations on a free-surface and terrain-following coordinates system (Shchepetkin and McWilliams 2005), which has been widely used in the study of oceanic processes and simulations (Liu et al 2014;Li et al 2016). The model domain is within the tropical Indian Ocean (30°E-110°E, 30°S-30°N) with a horizontal resolution of 1/8° and 32 vertical levels.…”

Cross-shelf transport of terrestrial Al enhanced by the transition of northeasterly to southwesterly monsoon wind over the East China Sea

“…The Kuroshio current, one of the strongest western boundary currents in the world, flows northeastward along the shelf break of the ECS, and its volume transport during 1955–2010 was 22.48 ± 2.78 Sv (1 Sv = 10 6 m 3 /s) at section PN (from the Changjiang Estuary to the Ryukyu Islands), with significant spatial and temporal variations in current speed and axis [ Hsin et al ., ; Wei et al ., , and references therein]. Observations and model experiments indicate that the Kuroshio intrudes into the ECS at northern end of Taiwan in winter [ Su and Pan , ; Tang and Yang , ; Guo et al ., ; Ichikawa et al ., ] and moves forward to form a large anticyclonic loop that manifests as a secondary maximum current core (SMCC) [ Liu et al ., ].…”

“…We also identified an important role of the monsoon, with a change from northeasterly wind to southwesterly wind in spring, on the cross-shelf transport of Al by use of numerical tracer experiments.PUBLICATIONS Wei et al, 2013, and references therein]. Observations and model experiments indicate that the Kuroshio intrudes into the ECS at northern end of Taiwan in winter [Su and Pan, 1987;Tang and Yang, 1993;Guo et al, 2006;Ichikawa et al, 2008] and moves forward to form a large anticyclonic loop that manifests as a secondary maximum current core (SMCC) [Liu et al, 2014].…”

Eddy analysis in the Eastern China Sea using altimetry data

“…There are two areas within the red rectangle with the largest EKE: one is northeast of Taiwan Island and the other is west of Tokara Strait. The former is well known for the Kuroshio intrusion into the shelf slope (e.g., Liu et al, 2014) and the latter is where the Kuroshio makes a sharp eastward turn. Both of them represent strong variations in the Kuroshio path.…”