IMOS - Ships of Opportunity - Ocean Carbon Dioxide Data from RV Southern Surveyor voyage SS012009

This data was collected in February and March 2009 by the IMOS Ship of Opportunity Underway CO2 Measurement research group on RV Southern Surveyor (IMOS platform code: VLHJ) voyage SS012009.Departed:     Wellington, New Zealand, February 03, 2009Arrived:     Nuku'Alofa, Tonga, February 25, 2009Departed:     Nuku'Alofa, Tonga, February 26, 2009Arrived:     Lautoka, Fiji, March 23, 2009CO2 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.

本数据集由澳大利亚海洋观测系统（IMOS）机会船舶走航CO₂测量研究小组，于2009年2月至3月期间，在RV Southern Surveyor（IMOS平台代码：VLHJ）航次SS012009中采集。

出港：新西兰惠灵顿，2009年2月3日
抵港：汤加努库阿洛法，2009年2月25日
出港：汤加努库阿洛法，2009年2月26日
抵港：斐济劳托卡，2009年3月23日

CO₂系统概述：
表层海水二氧化碳逸度（fugacity of carbon dioxide, fCO₂）的测量采用General Oceanics Inc.生产的自动化系统（型号8050；参考文献Pierrot等，2009）。具体测量流程为：将海水喷入平衡气室，顶空气体中的CO₂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），经纳菲恩干燥管（nafion drying tube）干燥，再通入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CO₂摩尔分数（XCO₂）。测量过程中临时停止气流，在常压下完成CO₂检测。每约4小时分析一组覆盖海洋环境预期CO₂浓度范围的标准气体，用于校准气体分析仪。标准气体浓度采用WMO-X2007空气CO₂摩尔分数标度。完成标准气体校准后，通过船舶前桅进气口抽取洁净外界空气，以测量大气干燥态XCO₂。

海水取水及辅助数据：
海水取水口位于船舶船首约5.5米水深处。CO₂系统旁配备的热电盐度计（Seabird Electronics SBE21），用于测量海表盐度。取水口处安装的远程温度传感器（Seabird Electronics SBE38）用于测量海表温度（Sea Surface Temperature, SST）。取水口至CO₂系统的输水时长通常约4分钟，输水过程中水温升高通常不超过0.6℃。热电盐度计的取水水源与CO₂系统同源，但输水管道在取水口处分流。对热电盐度计与平衡器的温度记录对比显示，两条输水管道间的温差通常小于0.1℃。热电盐度计的输水管道沿船外敷设，通常水温高于平衡器输水管道。热电盐度计的输水时长比平衡器输水管道快2.5分钟。
气象数据、盐度、海表温度、船舶位置及时间均取自船舶日志系统。上述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。