Noise in Ice-Tethered Profiler and McLane Moored Profiler velocity measurements

Abstract

In order to measure current profiles, and most recently, turbulent fluxes, moored profiling instrument have been equipped with acoustic travel-time current sensors. Noise in the measured currents has exceeded expectations. A customized Falmouth Scientific acoustic current sensor on a McLane Moored Profiler (MMP) has a standard deviation of measured velocity that is 4.4% of the profiler velocity in still water and a modified Modular Acoustic Velocity Sensor (MAVS) on an MMP and an Ice-Tethered Profiler (ITP) has a standard deviation of 4.6% of profiler velocity. Both of these sensors measure velocity along four acoustic paths and the water velocities were computed neglecting their downstream paths.