IMOS - SOOP Ocean Carbon Dioxide Data from RV Southern Surveyor voyage SS2012_T01 (Hobart-Brisbane)

This data was collected in April 2012 by the IMOS Ship of Opportunity Underway CO2 Measurement research group on RV Southern Surveyor (IMOS platform code: VLHJ) voyage SS2012_T01.\n\nDeparted: \tHobart, TAS, Apr 11, 2012\nArrived: \tBrisbane, QLD, Apr 18, 2012\n\nCO2 System Overview:\nThe fugacity of carbon dioxide (fCO2) in surface seawater was measured using a General Oceanics Inc. automated system (Model 8050; Pierrot et al 2009). Seawater is sprayed into an equilibration chamber and CO2 in the headspace gas equilibrates with the seawater. The headspace gas is pumped through a thermoelectric condenser followed by a nafion drying tube before flowing through a Licor 7000 non-dispersive infrared gas analyser used to measure the CO2 mole fraction (XCO2) of the dried air. The gas flow is stopped temporarily for the CO2 measurements, which are made at atmospheric pressure. A set of four CO2 standards that cover the range of CO2 values expected in the ocean are analysed about every four hours to calibrate the gas analyser. The standard gas concentrations are on the WMO-X2007 mole fraction scale for CO2-in-air. Atmospheric XCO2 (dry) is measured after the standards by pumping clean outside air from an intake on the forward mast of the ship. \n\nSeawater intake and ancillary data:\nThe seawater intake is located at about 5.5m depth in the bow of the ship. Sea surface salinity is measured using a thermosalinograph (Seabird Electronics SBE21) located next to the CO2 system. A remote temperature sensor (Seabird Electronics SBE 38) located at the intake is used to measure sea surface temperature (SST). The travel time between the intake and CO2 system is typically about 4 minutes with warming usually less than 0.6ºC. The thermosalinograph water is from the same intake, but the supply lines separate after the intake. A comparison of thermosalinograph and equilibrator temperature records shows the temperature difference in the two lines is generally less than 0.1ºC. The thermosalinograph water line travels outside the ship and is typically warmer than the equilibrator. The travel time in water line to the thermosalinograph is 2.5 minutes faster than to the equilibrator. \n\nMeteorological data, salinity, SST, and ships position and time are taken from the ships logging system. These parameters and the data quality are maintained by the Australian Marine National Facility.

本数据集由澳大利亚海洋集成观测系统（Integrated Marine Observing System, IMOS）的船舶走航二氧化碳测量研究小组，于2012年4月搭载“RV Southern Surveyor”号科考船（IMOS平台代码：VLHJ）执行航次SS2012_T01期间采集。

启航：塔斯马尼亚州霍巴特，2012年4月11日
抵达：昆士兰州布里斯班，2012年4月18日

二氧化碳测量系统概况：
表层海水二氧化碳逸度（fCO₂）采用General Oceanics公司生产的自动化检测系统（型号8050；Pierrot等，2009）进行测定。具体流程为：将海水喷入平衡腔室，使顶空气体中的二氧化碳与海水达到气液平衡。随后将顶空气体依次经热电冷凝器、纳菲恩（nafion）干燥管处理，再通入Licor 7000型非分散红外气体分析仪，以测定干燥空气中的二氧化碳摩尔分数（XCO₂）。测量过程中会暂时切断气流，在大气压条件下完成二氧化碳浓度测定。每间隔约4小时，使用覆盖海洋环境预期二氧化碳浓度范围的4瓶标准气体校准气体分析仪，标准气体的浓度基于WMO-X2007空气二氧化碳摩尔分数标尺。完成标准气体校准后，通过船艏桅杆前方进气口抽取洁净外部空气，测定大气干燥态XCO₂。

海水采样口及辅助观测数据：
海水采样口位于船艏约5.5米水深处。紧邻二氧化碳测量系统安装了热敏盐度计（Seabird Electronics SBE21），用于测定海表盐度；采样口处部署了远程温度传感器（Seabird Electronics SBE 38），用于测量海表温度（SST）。从采样口至二氧化碳测量系统的输水耗时通常约4分钟，输水过程中水温升高幅度一般低于0.6℃。热敏盐度计的供水同样取自该采样口，但输水管道在采样口后即与二氧化碳系统的管道分流。对比热敏盐度计与平衡腔的温度记录可知，两条输水管道内的水温差通常小于0.1℃。由于热敏盐度计的输水管道沿船体外布置，其管内水温通常高于平衡腔系统的输水管道。热敏盐度计的输水耗时比平衡腔系统快2.5分钟。

气象数据、盐度、海表温度、船舶位置与时间数据均取自船舶日志系统，相关参数及数据质量由澳大利亚海洋国家设施（Australian Marine National Facility）负责维护。