The TIC-MOC cruise onboard the R/V Hespérides, March 2015, Brazil-Malvinas Confluence

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).TIC-MOC海洋科考航次旨在表征巴西-马尔维纳斯汇合区（Brazil-Malvinas Confluence, BMC）的动力特征。本航次于2015年3月搭载于R/V Hespérides号科考船执行，从乌斯怀亚出发，最终抵达萨尔瓦多-巴伊亚。航次共设置66个水文测站，作业时段为2015年3月8日至22日。所有测站均位于大陆架外海，地理范围介于南纬45°至35°、西经61°至50°之间；其中14个测站直达海底，24个测站探测深度达2000米，28个测站探测深度为400~500米。温盐深（Conductivity-Temperature-Depth, CTD）数据通过SeaBird 911 Plus型多参数探头采集，该探头配备冗余盐度与温度传感器；溶解氧数据则采用SBE-43型传感器获取。各测站的水流速度数据由下放式声学多普勒流速剖面仪（lowered acoustic Doppler current profiler, LADCP）采集，船舶航迹沿线的流速数据则通过船载ADCP（vessel-mounted ADCP, VADCP）获取。由于朝上的LADCP发生进水故障，多数测站仅使用300 kHz朝下的LADCP记录流速，垂直分层分辨率为4米。在研究区域内的全部航迹上，VADCP以低量程模式采集流速数据：每5分钟获取一组流速剖面，探测范围约20~700米，垂直分层为8米；同时走航式温盐监测仪每5秒采集5米水深处的盐度与温度数据。LADCP与CTD一同挂载于12升容积的24瓶尼斯金采水器阵列。采水器在标准深度采集的水样被用于校准盐度与溶解氧传感器，同时用于测定4种无机营养盐（硝酸盐、亚硝酸盐、磷酸盐与硅酸盐）的浓度。航次初期共投放8个水下漂流浮标（拖曳深度为100米或200米），同时部署2台剖面浮标，在约一周时间内完成总计42组剖面探测，最大探测深度约800米。本航次首席科学家为Josep Pelegrí，首席技师为Ramon Ametller，船长为Julio Albaladejo。本航次由西班牙政府通过项目"经向翻转环流的临界转折点"（Tipping Corners of the Meridional Overturning Circulation, TIC-MOC，项目编号CTM2011-28867）资助。