Turbulence and optics sampling from an autonomous underwater vehicle

Abstract

The adaptation of synergistic sensor technologies to AUV platforms enables a new class of sampling strategies not available with older technologies. The combined turbulence, optics, and hydrographic data acquisition capabilities can be utilized for near-synoptic horizontal mapping in a variety of estuarine and continental shelf process studies. Horizontal profiles of turbulence are obtained using two piezoceramic shear probes orthogonally to the direction of motion, a single ultrafast thermistor, and three orthogonal accelerometers, mounted on a sting. Horizontal profiles of optical absorption and attenuation are obtained with a WET Labs AC-9 instrument mounted in a wet well, with the proper flow rate provided by a pump. Field trials in the Narragansett Bay tidal estuary in January 1996 resulted in obtaining turbulence and optical data from the UUV during near-spring ebb tide. UUV-based observations were made in the deep pycnocline, as well as in the ocean surface layer during wind row occurrences. A portion of the data has been examined for evaluation of noise effects on the turbulence data. In general, this analysis that meaningful estuarine turbulence data can be obtained from an autonomous underwater vehicle, and its relation to the optics data can be studied.