default Testing the Wirewalker profiling system for high-frequency underwater dynamics characterization

Testing the Wirewalker profiling system for high-frequency underwater dynamics characterization. Poulain, Pierre-Marie; Stoner, Richard; Lewis, Craig; Ampolo Rella, Marina; Cozzani, Elisa. CMRE-MR-2019-022. April 2020.

The Wirewalker profiling system is a new ocean sensing platform able to host a wide variety of sensors to measure high-frequency underwater environmental dynamics. It is an energy-efficient mechanical system that harnesses the power of the surface waves and uses buoyancy to profile up and down in the water column. The system rapidly collects oceanographic data with high vertical resolution from the surface to 200-300 m depth with a typical profiling period of 10-15 minutes. The first Wirewalker acquired by the Centre for Maritime Research and Experimentation in 2019 and it was tested in the Ligurian Sea and then was operated during the NARVAL19 sea trial at high latitudes (south-west of Svalbard, Norway and in the western Barents Sea). Technical details about the Wirewalker and about its operation are discussed in this report, with particular focus on its functioning in moored configuration, including information on the profiling speed and wire inclination. The oceanographic data collected with this instrument at high latitudes revealed small-scale structures associated with fronts separating warm and salty waters of Atlantic origin from cool and fresher waters of polar origin. In addition, the data display the strong temporal variability of water mass properties (e.g., temperature) and sound speed due to the presence of strong internal waves at tidal frequencies. In this report, recommendations are made for the future operation of Wirewalkers to collect NATO-relevant marine environmental data.