A vertical automatic profiling system

Improved understanding of energy dissipation processes within lakes requires measurements with high spatial and temporal resolution. Such measurements can be economically made over extended periods by an instrumented automatic profiling mechanism. The various means of achieving continuous profiling are reviewed, followed by a description of such a device constructed at the Canada Centre for Inland Waters. It consists of a buoyant sensor vehicle which traverses 150 m of water via a lightweight tether cable and a bottom-mounted winch. A 2 km long cable from shore carries electrical power and control signals to the unit. Time, depth, temperature, X and Y current speeds, compass heading, roll and pitch signals are telemetered back to a recorder on shore. Finally, certain limitations of the system are discussed with emphasis on careful calibration.