IMOS - Ships of Opportunity - Ocean Carbon Dioxide Data from RV Southern Surveyor voyage SS012010 (Sydney-Hobart)

This data was collected in January and February 2010 by the IMOS Ship of Opportunity Underway CO2 Measurement research group on RV Southern Surveyor (IMOS platform code: VLHJ) voyage SS012010.Departed: Sydney, Australia, January 22, 2010Arrived:      Hobart, Australia, February 15, 2010CO2 System Overview:The 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. Seawater intake and ancillary data:The 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. Meteorological 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IMOS机会船走航二氧化碳测量研究小组，于2010年1月至2月期间，在“南方考察者号”（RV Southern Surveyor）科考船（IMOS平台代码：VLHJ）的SS012010航次中采集。
出港：澳大利亚悉尼，2010年1月22日；
抵港：澳大利亚霍巴特，2010年2月15日。

二氧化碳系统概述：
采用通用海洋学公司（General Oceanics Inc.）自动化系统（型号8050；参考Pierrot等人2009年研究）测量表层海水二氧化碳分压（fugacity of carbon dioxide, fCO₂）。具体流程为：将海水喷入平衡舱（equilibration chamber），使顶空气体（headspace gas）中的二氧化碳与海水达到气液平衡。随后将顶空气体泵送至热电冷凝器（thermoelectric condenser），再经纳菲隆干燥管（nafion drying tube）去除水汽，之后流经Licor 7000型非色散红外气体分析仪（non-dispersive infrared gas analyser），以测量干燥空气中的二氧化碳摩尔分数（CO₂ mole fraction, XCO₂）。测量过程中会临时暂停气流，且所有测量均在大气压条件下进行。每间隔约4小时，会使用一套覆盖海洋环境预期二氧化碳浓度范围的4种二氧化碳标准气体对气体分析仪进行校准。标准气体的浓度基于WMO-X2007空气中二氧化碳摩尔分数刻度（WMO-X2007 mole fraction scale for CO₂-in-air）。完成标准气体校准后，通过船舶前部桅杆上的进气口抽取外部清洁空气，以测量大气干燥态XCO₂。

海水采集及辅助数据：
海水采样口位于船艏约5.5米水深处。紧邻二氧化碳分析系统安装了热盐计（thermosalinograph，Seabird Electronics SBE21），用于测量海表盐度。采样口处布设了远程温度传感器（remote temperature sensor，Seabird Electronics SBE 38），用于测量海表温度（Sea Surface Temperature, SST）。从采样口至二氧化碳分析系统的输水时长通常约为4分钟，且输水过程中的水温升高幅度通常小于0.6℃。热盐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。对热盐计与平衡舱的温度记录进行比对后发现，两条管道的水温差通常小于0.1℃。热盐计输水管道沿船体外布设，因此水温通常高于平衡舱输水管道。热盐计输水管道的输水时长比平衡舱管道快2.5分钟。

气象数据、盐度、海表温度、船舶位置及时间信息均取自船舶日志系统。上述参数及对应数据质量均由澳大利亚海洋国家设施（Australian Marine National Facility）负责维护。