Flow fields around the Emperor Seamounts detected from current data

Abstract

Bathymetric influences of the Emperor Seamounts (ESs) on the local and large‐scale flow fields in the subarctic North Pacific were investigated by analyzing data of directly measured velocity obtained using Argo floats, near‐surface buoys, and moored current meters. The local influences were evident in notable deflections of two relatively strong (∼0.05 m s−1) eastward flows over ESs. A Taylor cap induced by the eastward flow impinging against the Nintoku Seamount (around 42.0°N, 170.5°E) was clearly identified in the climatological flow field at 1000 m depth. This flow pattern was also identified in the near‐surface flow field (15 m depth) and dynamic height field at 200 dbar relative to 2000 dbar, indicating the Taylor cap is stable or frequently generated and extends to the surface. An anticyclonic flow was found over the Suiko Seamount (around 45.0°N, 170.5°E). The influences on the large‐scale flow field were found in data obtained from current meters moored over the southeastern flank of the Suiko Seamount and Argo float trajectories. These data indicate for the first time from velocity observations that there is a seasonally varying boundary current along the eastern side of ESs partially compensating for the Sverdrup transport to the east of ESs, and hence, the seasonally varying component of the subarctic gyre in the North Pacific is divided into two subgyres by ESs.