RRS Charles Darwin Cruise CD171, 01 May - 15 Jun 2005. A trans-Atlantic hydrographic section at 36N

• Main Author: McDonagh, E.L.
• Format: Book
• Language: English
• Published: National Oceanography Centre 2007
• Subjects: North Atlantic
• Online Access: https://eprints.soton.ac.uk/44333/; https://eprints.soton.ac.uk/44333/1/nocscr014.pdf

A new hydrographic section was taken across 36?N in the Atlantic Ocean during May-June 2005 aboard RRS Charles Darwin (CD171). The primary objectives of this work were to measure the meridional fluxes of heat, nutrients and CO2. This coast-to-coast, zonal data set represents the first full repeat of this section since 1981. A total of 144 CTD/LADCP stations were sampled across the North Atlantic subtropical gyre. In addition to temperature, salinity and oxygen profiles from the CTDO2 package, water samples from a 24-bottle rosette were analysed for salinity, dissolved oxygen and inorganic nutrients at each station. In addition water samples were collected and analysed onboard ship for SF6, CFCs, pCO2, TIC and alkalinity and samples were collected for shore-based analyses for He/Tr, organic nutrients and organic carbon. Full depth velocity measurements were made at every station by up to two ADCP's mounted on the rosette frame. Throughout the cruise velocity data in the upper few hundred meters of the water column were provided by an ADCP mounted in the ship's hull, and continuous measurements of near-surface water temperature, salinity and pCO2 were made. Meteorological variables were monitored and samples of air and rainfall were periodically collected. In addition stand alone pumps were deployed 13 times and samples were collected for shore-side analyses of nitrogen isotopes, pigments and carbon and nitrogen. During the cruise two fibre optic gyrocompasses were trialled both on the bench and mounted on the rosette. This report describes the methods used to acquire and process the data on board the ship during cruise CD171.