A Recent Full-Depth Survey of the Alaskan Stream

Abstract

We examine results from a cruise in May 1997. CTD casts to near the bottom were made south of the Aleutian Islands, across Amchitka Pass, and north of the islands. We computed a westward geostrophic speed of 123 cm s−1 at 173.5°W in the Alaskan Stream. The computed volume transport there, referred to the bottom, was 25×106m3s−1. On other similar sections, transports were 8–15 × 106 m3s−1. Various complex variations in geopotential height along the Stream apparently altered the cross-stream gradients, and hence the transports. Rotational tendencies were also present. Northward inflow through Amchitka Pass was quite strong (6 × 106 m3s−1). Data north of the islands supported the existence of a zero-velocity reference level of variable depth.