Dynamic Response Calibration of the Nell Brown Conductivity Cell

Abstract

Appl. Phys. Lab., Sch. Oceanogr., Univ. Washington, Seattle, WA 98105, USA J (Journal-Article) M (Marine) Dynamic response calibrations and flow visualization studies have been made for the standard, 3 cm long conductivity cell produced by Neil Brown Instrument Systems. This probe is used on wire-lowered CTD's as well as on vehicles that move freely through the ocean. The step response of the cell was measured by propelling the conductivity cell and a much smaller "needle" cell through sharp interfaces at speeds ranging from 5 mm s super(-1) to 3.1 m s super(-1). Cross-spectral analysis of the two records yielded the amplitude-squared and phase-response functions. Using maps of the electric field around and within the cell together with the flow visualizations, it was found that the principal factors determining the response functions are the distribution of the electric field, which produces a "dead band" within the cell, and a diff...