Measurement of deep ocean currents using recording inclinometers

Abstract

A commercial recording inclinometer was adapted to the measurement of ocean currents from a long moored vertical line. The present evolution of the concept is represented by General Oceanics Model 6011 current meter. Measurements of deep-ocean currents south and southeast of Bermuda were made in the fall of 1974 on two separate deployments of approximately two weeks each, at depths between 90 meters and 5,290 meters. Shallow currents showed a generally northeasterly set while deep currents were variable, but mostly to the south and southwest. Data presentation, in sequential and progressive vector plots and in power spectral analysis, show the influence of inertial and tidal currents. The advantages of this type of instrument to the long-term measurement of deep ocean currents is described. Instrument characteristics and limitations are discussed along with techniques for obtaining accurate calibration data.