Observations of New, Large and Stable Abyssal Currents at Midlatitudes along 165°E

Abstract

Abstract Unexpectedly large and stable abyssal mean flow have recently been observed along 165°E, between 31° and 41°N. These results are based on two deployments of a moored array for approximately a year each. Time-averaged currents at 4000 m are about 5 ± 0.5 cm s−1 to the southwest near 41°N and 6 ± 0.9 cm s−1 to the northwest near 33°N, on opposite of the Kuroshio Extension. These mean flows were reproduced between array deployments to within a fraction of a cm s−1 and few degrees (True). At 41°N the abyssal mean kinetic energy is several times larger than eddy kinetic energy so that the flow visually does not reverse. At 33°N, near the southern edge of the Kuroshio Extension, the abyssal mean and eddy fields are of roughly the same amplitude. These result along 165°E are in contrast to similar observations along 152°E, where the abyssal zonal mean flows are notably less stable than at 165°E. However, estimates of the latitudinal and two-years averaged zonal flow components are approximately the same...