RRS Discovery Cruise DY054, 27 Jul - 17 Aug 2016, Reykjavik to Southampton. OSNAP 2016 mooring refurbishment cruise, Leg 2

Cruise DY054 was the second leg of the 2016 UK OSNAP mooring refurbishment programme on RRS Discovery. Following the first leg (DY053, Cunningham et al 2016) which serviced and re-deployed US and UK moorings in the Iceland Basin and Rockall Trough, the scientific objectives of DY054 were: To service (recover and re-deploy) the 5 UK OSNAP moorings in the western Irminger Sea (the Deep Western Boundary Array, M1-M5) To service the 5 Dutch OSNAP moorings in the eastern Irminger Sea (the Irminger Currrent Array, IC0-IC4) To service the Dutch LOCO mooring in the central Irminger Sea To complete a CTD/LADCP section across the Irminger Basin, from the Greenland coast to the mid-Atlantic Ridge To collect and freeze nutrient samples from CTD stations for later analysis by NIOZ To deploy an Argos float for the UK Met Office To deploy a series of OSNAP RAFOS floats in the overflow waters To deploy a new WHOI sound source in the Maury Channel of the Iceland Basin To collect material for outreach programes, including film footage, audio recordings and photography for a US OSNAP website, and material to be used in an art project All objectives were achieved. All OSNAP moorings were previously deployed in 2014, refurbished in 2015, and will be recovered in 2018. The moorings and the CTD profiles will be used to measure the mean and variability of the surface-to-seafloor currents, and to compute the volume, heat and freshwater transport within the currents. They are part of a large international programme, OSNAP (Overturning in the Subpolar North Atlantic Programme) which has other moorings in the Labrador Sea, Iceland Basin and Rockall Trough.