RRS Discovery Cruise 382, 08 Oct - 24 Nov 2012. RAPID moorings cruise report

McCarthy, G.; et al, .. 2012 RRS Discovery Cruise 382, 08 Oct - 24 Nov 2012. RAPID moorings cruise report. Southampton, UK, National Oceanography Centre Southampton, 196pp. (National Oceanography Centre Cruise Report 21)

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Abstract/Summary

This cruise report covers scientific operations conducted during RRS Discovery Cruise 382. The purpose of the cruise was the refurbishment of an array of moorings spanning the latitude of 26.5°N from the Canary Islands to the Bahamas. Di382 departed from Southampton on Monday 8th October 2012, calling at Santa Cruz de Tenerife and Nassau, Bahamas before finally docking in Freeport, Bahamas on the 24th November 2012 after 47 days at sea. The full itinerary is described in Section 2. The moorings are part of a purposeful Atlantic wide mooring array for monitoring the Atlantic Meridional Overturning Circulation and Heat Flux. The array is a joint UK/US programme and is known as the RAPID-WATCH/MOCHA array. The array as serviced on Di382 consisted of a total of 17 moorings, 7 landers. This added to 7 landers and a single inverted echo sounder that had been deployed already. The US contributes 3 full depth moorings and 2 landers to the array. A full introduction is included in Section 3. During Di382 we recovered and redeployed: EBH1, EBH1L, EBH2, EBH3, EBHi, EB1, EB1L, EBH4, EBH4L, MAR3, MAR3L, MAR2, MAR1, WB6, WB1, WB4, WB4L, WB2, WB2L, WBH2, WBAL, WBADCP. EBH5 was recovered but not re-deployed. MAR1L, MAR0 were not recovered but were redeployed. WBP1 was the first deployment of a PIES lander in the western boundary. A sediment trap mooring NOGST was also recovered and redeployed for the Ocean Biogeochemistry and Ecosystems Group at the NOCS. Mooring operations and data processing are described in Sections 8 and 9. Diagrams of deployed moorings are included in Section 20. Logsheets of all recoveries and deployments of moorings are included in Sections 21 and 22. CTD stations were conducted throughout the cruise for purposes of providing pre- and postdeployment calibrations for mooring instrumentation and for testing mooring releases prior to deployment. CTD operations and data processing are described in Sections 6 and 7. Shipboard underway measurements were systematically logged, processed and calibrated, including: surface meteorology, 6m depth sea temperatures and salinities, water depth, navigation. Water velocity profiles from 15 m to approximately 800 m depth were obtained using a ship mounted 75 kHz acoustic Doppler current profiler. Shipboard measurements are described in Sections 4 and 5. Five APEX argo floats and five SVPs (surface velocity probes), supplied by the Met Office, were deployed during the cruise. Nine SVP plus salinity drifters were deployed for the SPURS project. These are described in Section 10. Summaries of instruments tested on CTDs, moored instrument record lengths, lost/damaged instruments, deployments, recoveries, acoustic releases and all RAPID cruises are included in Sections 13 to 19. (http://www.noc.soton.ac.uk/rapid)