The TIC-MOC cruise onboard the R/V Hespérides, March 2015, Brazil-Malvinas Confluence
Description
The TIC-MOC oceanographic cruise was designed to characterize the dynamics of the Brazil-Malvinas Confluence (BMC) region. The cruise was carried in March 2015 on board the R/V Hespérides, departing from Ushuaia and arriving to Salvador de Bahía. There were a total of 66 hydrographic stations, carried out between 8 and 22 March 2015. All stations were offshore from the continental platform and within 45ºS-35ºS and 61ºW-50ºW, with 14 stations reaching down to the seafloor, 24 stations down to 2000 m and 28 stations down to 400-500 m. Conductivity-temperature-depth (CTD) data were obtained with a SeaBird 911 Plus multi-parametric probe, with redundant salinity and temperature sensors, and dissolved oxygen was sampled with a SBE-43 sensor. Water velocity data was obtained at the stations with a lowered acoustic Doppler current profiler (LADCP) and along the ship’s track with the vessel-mounted ADCP (VADCP). Due to the flooding of the upper-looking LADCP, for most stations the velocity was recorded using only the 300 kHz downward looking LADCP, at 4-m vertical bins. During the entire ship’s track inside the study region, the VADCP gathered velocity data in low-range mode (one velocity profile every 5 min between about 20 and 700 m at 8-m depth bins) and a thermosalinograph gathered salinity and temperature data (every 5 s at a depth of 5 m). The LADCP was attached, together with the CTD, to a 12-liters 24-Niskin-bottle rosette. Water samples from the Niskin bottles at standard depths were used to calibrate the salinity and DO sensors, as well as to determine the concentration of four inorganic nutrients (nitrate, nitrite, phosphate and silicate). Finally, eight subsurface drifters (dragged at either 100 or 200 m) were released early in the cruise and two profiling floats were launched and carried out a total of 42 profiles (down to about 800 m) during about one week. The cruise’s chief scientist was Josep Pelegrí, the chief technician was Ramon Ametller and the vessel’s captain was Julio Albaladejo. The cruise was supported by the Spanish Government through project “Tipping Corners of the Meridional Overturning Circulation” (TIC-MOC, reference number CTM2011-28867).