A Study of Geostrophy in Tropical Pacific Ocean Currents during the NORPAX Tahiti Shuttle using a Shipboard Doppler Acoustic Current Profiler

Abstract

Scripps Inst. Oceanogr., NORPAX-A030, Univ. California, La Jolla, CA 92093, USA ISSN 0022-3670 J (Journal-Article) M (Marine) Continuous velocity measurements from a shipboard Doppler acoustic log on the NORPAX shuttle experiment in the central equatorial Pacific are presented. The time mean of these velocities shows the classical zonal equatorial currents as well as their meridional circulation. The velocities are used with concurrent CTD data to examine the geostrophic balance of zonal currents in the upper 117 m. Estimates of the errors of the acoustic data are produced from a comparison between that data and concurrent profiling current-meter data, and are used to establish the reliability of the balances observed. Both the time mean and the time varying balances are investigated, as well as the departures from geostrophic balance. The mean zonal velocities between 4 degree S and 10 degree N are found to be in approximate geostro...