RREX 2015. CTD-O2 Data report

The Reykjanes Ridge is a major topographic feature of the North-Atlantic Ocean. It lies in a central position along the main paths followed by the upper and lower limbs of the Meridional Overturning Cell (MOC), which contributes at moderating the European climate in creating a transport of heat toward the North Atlantic. Our hypothesis is that the Reykjanes Ridge influences the main components of the upper and lower limbs of the MOC because it is a strong constraint on the horizontal and vertical circulation, it impacts the water mass distribution and evolution and it is a region of intense turbulent mixing. The objective of the RREX project is to conduct a process study in order to better understand the role of the Reykjanes Ridge on the dynamics and water mass transformation in the subpolar gyre and ultimately on the MOC. This project relies on two hydrographic cruises to acquire the adequate dataset to (1) provide a synoptic high-resolution and full depth survey to monitor the flow along and across the ridge, (2) to quantify the variability of the vertical and horizontal structure of the currents parallel to the ridge at daily to seasonal time-scales and (3) to provide sufficient turbulence observations to monitor the heterogeneous and intermittent mixing processes. The RREX2015 cruise, carried out from the 5th of June to the 10th of July 2015, is the first of the two cruises of the RREX project. During this cruise, we realized 133 surface-bottom CTDO2-LADCP stations along 4 sections : the south section sud (GHI)), the so-called Ovide la section (DEF), the north section (ABC) and the main axis (BEHJ). At each station, the following measurements were carried out: (1) pressure, temperature, conductivity and dissolved oxygen measurements with a CTDO2 probe, (2) current measurements with an ADCP, (3) samples of sea water at 28 levels for salinity and oxygen calibration and for nutrients and pH measurements...