A moored instrument for vertical temperature gradients

Abstract

Vector averaging current meters have been modified to measure the temperature gradient in addition to current and absolute temperature. The modified instrument measures the temperature difference between sensors spaced vertically 1.74 m apart (or closer) using thermistors in a Wheatstone bridge circuit. Calibrations provide corrections for drift and static offset resulting in temperature gradient measurements accurate to about 0.5 m ~c;m. Originally developed to infer vertical velocities, the instrument has also been successfully used to study mixed layer motions and thickness variations and to investigate temperature fine structure.