Expendable Dissipation Profiler

A relatively inexpensive expendable instrument has been developed to measure the vertical gradient of oceanic velocity on scales small enough to produce profiles of the viscous dissipation of kinetic energy. The instrument consists of a velocity shear probe and a thermistor mounted on a modified Sippican T-4 XBT. The measured current shear and temperature are internally amplified and converted to FM signals which are telemetered to the surface over a standard XBT wire link. The received FM signals are demodulated by a 2nd order phase- locked loop to reproduce the analog signals of shear and temperature with a fulI scale range of ±5 volts for data logging by computer and real- time display by graphic recorders. Fifteen proto- type instruments have been sea tested. The shear resolution is presently better than 10^-2 sec^-1 comparable to non-expendable instruments.