A Moored Profiling Instrument*

Abstract

The specifications and performance of a moored vertical profiling instrument, designed to acquire near-full-ocean-depth profile time series data at high vertical resolution, are described. The 0.8-m-diameter by 0.4-m-wide device utilizes a traction drive to propel itself along a standard mooring wire at a speed of ?0.3 m s?1. The average power required to profile at this speed is 1?2 W; the present sensor suite and controller draw about 1.5 W. Based on these figures, the instrument?s battery capacity will support approximately 1 million meters of profiling. Instrument actions are regulated by an onboard microcontroller, allowing complex dive programs to be carried out. Oceanographic and engineering data are recorded internally on a hard disk interfaced to the controller. The measurement suite thus far deployed includes a CTD for deriving ocean temperature and salinity profiles, and an acoustic current meter that returns ocean velocity profile data. Addition of other oceanographic sensors is anticipated. Results from several trial deployments in the open ocean are reported.