IMOS - Ships of Opportunity - Ocean Carbon Dioxide Data from RV Southern Surveyor voyage ST012008

This data was collected in April 2008 by the IMOS Ship of Opportunity Underway CO2 Measurement research group on RV Southern Surveyor (IMOS platform code: VLHJ) voyage ST012008.Departed:     Hobart, Tasmania, April 10, 2008Arrived:     Sydney, New South Wales, April 14, 2008CO2 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.

本数据集于2008年4月由IMOS机遇船舶走航CO₂测量研究小组，在RV Southern Surveyor（南方调查者号，IMOS平台代码：VLHJ）执行航次ST012008期间采集。起航地点：澳大利亚塔斯马尼亚州霍巴特，2008年4月10日；抵达地点：澳大利亚新南威尔士州悉尼，2008年4月14日。

CO₂系统概况：本研究采用General Oceanics Inc.自动化系统（型号8050；参考Pierrot等2009年研究）测量表层海水二氧化碳分压（fCO₂）。具体流程为：将海水喷入平衡腔，顶空气体中的CO₂与海水达成气液平衡。随后将顶空气体依次经热电冷凝器、纳菲昂（nafion）干燥管输送，再通过Licor 7000型非分散红外气体分析仪，测量干燥空气的CO₂摩尔分数（XCO₂）。CO₂测量环节会暂时暂停气流，所有测量均在大气压下开展。每约4小时分析一组覆盖海洋预期CO₂浓度范围的4种CO₂标准气体，以完成气体分析仪的校准。标准气体浓度采用WMO-X2007空气CO₂摩尔分数尺度。完成标准气体校准后，通过船舶前桅杆的进气口抽取清洁室外空气，用于测量大气干燥态XCO₂。

海水采样及辅助数据：海水采样口位于船舶艏部约5.5米水深处。CO₂系统旁配备热盐计（Seabird Electronics SBE21），用于测量海表盐度。采样口处安装远程温度传感器（Seabird Electronics SBE 38），用于测量海表温度（SST）。采样口至CO₂系统的输水时长通常约4分钟，输水过程中海水升温通常小于0.6℃。热盐计的供水来自同一采样口，但供水管道在采样口后即分支。对热盐计与平衡腔的温度记录进行对比后发现，两条输水管道的水温差通常小于0.1℃。热盐计输水管道沿船舶外部铺设，通常温度高于平衡腔输水管道。热盐计输水管道的输送时长比平衡腔输水管道快2.5分钟。

气象数据、盐度、SST、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由澳大利亚海洋国家设施（Australian Marine National Facility）负责维护。