DORADO/DOLPHIN: A Unique Semi-submersible Autonomous Vehicle for Ocean Field Experiments.

The Ocean Science and Technology research group (CERC.OCEAN) at Dalhousie University focuses on new approaches to the design and development of autonomous platforms to study biogeochemical and ecological changes in the world's oceans. Mesoscale “patch” experiments involving tracers are used to test hypotheses (e.g. iron fertilization) and examine near-surface processes and air-sea exchange. Such experiments typically require mapping of rapidly-evolving properties on scales of 10’s to 100’s of kilometers. These experiments typically employ a research vessel to monitor patch movement and to support process studies: however allocation of expensive vessel time between these uses can be problematic. We present a class of autonomous vehicle with unique potential for mesoscale mapping and experimental science at sea. The Dorado/Dolphin semi-submersibles, manufactured by International Submarine Engineering Ltd., travel just below the sea surface. A surface-piercing, “snorkel” mast allows use of a diesel engine allowing speeds of up to 16 knots and sufficient power for support of complex payloads. A tow-body can profile to 200m. The mast allows air sampling with near-zero atmospheric disturbance as well as remote sensing of the sea surface. The characteristics of this type of vehicle will be compared with those of other available platforms. We will report on our adaptation of the vehicle for measurement of gases and purposeful tracers (e.g. SF₅CF₃) as well as properties such as T, S, pCO₂, O₂, fluorescence, etc. and present and solicit ideas for the vehicles’ further application/use for ocean science.