IMOS - SOOP Ocean Carbon Dioxide Data from RV Southern Surveyor voyage ST022009

This data was collected in July and August 2009 by the IMOS Ship of Opportunity Underway CO2 Measurement research group on RV Southern Surveyor (IMOS platform code: VLHJ) voyage ST022009.\n\nDeparted: \tNoumea, New Caledonia, July 29, 2009\nArrived: \tHobart, Tasmania, August 6, 2009\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观测系统（Integrated Marine Observing System, IMOS）机遇船舶走航CO₂测量科研小组，于2009年7月至8月在‘南方考察者号’（RV Southern Surveyor，IMOS平台代码：VLHJ）的ST022009航次中采集。

出发地：新喀里多尼亚努美阿，2009年7月29日
抵达地：塔斯马尼亚州霍巴特，2009年8月6日

CO₂系统概况：
表层海水二氧化碳分压（fugacity of carbon dioxide, fCO₂）采用General Oceanics公司自动化系统（型号8050；Pierrot等，2009）进行测量。具体流程为：将海水喷入平衡舱，使顶空气体中的CO₂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CO₂摩尔分数（CO₂ mole fraction, XCO₂）。CO₂测量环节会暂时中断气流，所有测量均在大气压条件下开展。每约4小时即分析一组覆盖海洋典型CO₂浓度范围的4种CO₂标准气，用于校准气体分析仪；标准气的浓度基准为WMO-X2007空气中CO₂摩尔分数标尺。完成标准气校准后，通过船舶前桅杆进气口抽取洁净外部空气，用以测定大气干燥态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。海表盐度采用紧邻CO₂系统部署的热盐深仪（Seabird Electronics SBE21）测量；取水口处安装的远程温度传感器（Seabird Electronics SBE 38）用于测定海表温度（Sea Surface Temperature, SST）。取水口至CO₂系统的输水时长通常约4分钟，输水过程中的水温升高通常小于0.6℃。热盐深仪的取水同样源自该取水口，但输水线路在取水口后即与CO₂系统管路分离。对比热盐深仪与平衡舱的温度记录可知，两条管路的温度差普遍小于0.1℃；热盐深仪的输水线路沿船舶外壁铺设，通常水温高于平衡舱管路，且其输水时长较平衡舱管路短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。