A subsurface pathway for low potential vorticity transport from the central North Pacific toward Taiwan Island

Analysis of the Simple Ocean Data Assimilation product reveals that the central North Pacific (28°N–35°N, 150°E–170°W) is one of the main formation regions for low potential vorticity water of density between 25.4σθ and 25.8σθ. It is found that the low potential vorticity water is transported from the central North Pacific toward the east of Taiwan Island along a subsurface pathway following the subtropical gyre circulation, and it takes approximately 12 years. Propagation of pycnocline thickness anomalies is detected along the pathway, in association with the decadal variability of the subduction rate.