The abyssal and deep circulation of the Northeast Pacific Basin

Three-dimensional abyssal and deep circulation of the region to the east and north of the Emperor Seamount Chain/Hawaiian Ridge is determined from a compilation of CTI) and Argo float data, using a new over determined inverse technique for the geostrophic reference velocity and diapycnal/lateral mixing coefficients. The Northeast Pacific Basin is primarily sourced from its northern boundary, at a rate of 3.5 Sv across 47 degrees N below 3000 m. Bottom water in the western subarctic gyre recirculates cyclonically between the Emperor Seamount Chain and 155 degrees W. Bottom water east of 155 degrees W takes a more direct path southward along the flank of a broad topographic slope. In the deep water, a ridge of potential vorticity lying along the Mendocino Fracture Zone separates circulation systems north and south of similar to 40 degrees N. The region has very weak diapycnal and lateral mixing, and an aspect ratio for the overturning circulation that is correspondingly flat, with bottom water parcels rising less than 1 km during their long transit from the Aleutian Trench to the latitude of Hawaii.