Monitoring the dispersion of an intentionally released tracer, SF5CF3 with an instrumented, unmanned surface vehicle

We describe the physical and operational characteristics of an autonomous platform for ocean observation which has considerable potential for tracer dispersion and gas exchange studies. The Dorado (International Submarine Engineering, Port Coquitlam, B.C.) is an 8.2 m long, 1.2 m in diameter, snorkelling, semi-submersible vehicle powered by a 315 kW Caterpillar marine diesel engine. Capable of cruising at 8 m s^-1 (16 knots) for sustained periods of up to 28 hours, the vehicle´s linear range is on the order 1 × 10³ km. We further describe plans for the Dorado´s maiden scientific voyage. The vehicle will be equipped with a novel, compact, unattended GC and membrane-based equilibrator, as well as, supporting instrumentation. The vehicle will be used to monitor the dispersion of the deliberate tracer, SF₅CF₃, following a surface injection on the Scotian Shelf during the summer/fall of 2016. The analytical system will be tuned for the detection of the SF₅CF₃ and SF₆.