A study designed to investigate the Kuroshio Extension System from 2001 to 2005. The goal is to understand the mechanisms that govern the Kuroshio Extension and associated recirculation gyre variability, and to identify the processes responsible for interannual variations in upper–ocean heat content and SST in the region. The objectives of KESS are:

to demonstrate the capability of tomographic techniques in monitoring the variabiity of the 1000 km scale 3–D oceanic structures; and

to obtain information about the acoustic environment for the design of the tomography array. KESS will deploy eight reciprocal tomography moorings in the Kuroshio Extension (centered on 35°N, 150°W) for four years to study the climatological relevance of the Kuroshio Extension/mode water variability.