RRS James Cook Cruise JR16005, 17 Mar - 08 May 2017. The Dynamics of the Orkney Passage Outflow (DynOPO)

The RRS James Clark Ross JR16005 expedition (Punta Arenas, 17 March 2017 – Montevideo, 8 May 2017) was the primary fieldwork element of the Dynamics of the Orkney Passage Outflow (DynOPO) project. The cruise had two main goals: (1) to conduct measurements of the hydrographic properties, velocity and turbulent processes of the Antarctic Bottom Water outflow along its pathway through the Orkney Passage region; and (2) to turn around a set of long-term moorings deployed in the area by BAS and LDEO scientists, including recovery of additional instruments on some of the moorings deployed by DynOPO investigators 2 years previously. Operations were generally suc- cessful. With regard to goal (1), a total of 120 hydrographic and / or microstructure stations were occupied across the study region; 3 focussed surveys of two major sills in the area were performed with the autonomous underwater vehicle Autosub Long Range; and an array of moored sensors measuring turbulent processes at high spatio-temporal resolution was deployed for the duration of the cruise, with partial instrument failures. In respect of goal (2), all moorings were successfully recovered and re-deployed, and the return of additional DynOPO instruments was close to 100%.