IMOS - Ships of Opportunity - 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.Departed:     Hobart, TAS, Apr 11, 2012Arrived:     Brisbane, QLD, Apr 18, 2012CO2 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2012年4月由IMOS机遇船舶走航CO₂测量研究小组，在“南方探索者号”（RV Southern Surveyor，IMOS平台代码：VLHJ）的SS2012_T01航次中采集。
本次航次于2012年4月11日从塔斯马尼亚州（TAS）霍巴特港启航，2012年4月18日抵达昆士兰州（QLD）布里斯班港。

CO₂系统概述：
本研究采用General Oceanics公司自动化系统（型号8050；Pierrot等，2009）测量表层海水二氧化碳分压（fCO₂）。具体流程为：将海水喷入平衡舱，使顶空气体中的CO₂与海水充分平衡；随后将顶空气体经热电冷凝器、纳菲昂干燥管后，送入Licor 7000型非分散红外气体分析仪，以测量干燥空气中的CO₂摩尔分数（XCO₂）。CO₂测量在常压下进行，测量过程中会暂时中断气流。约每4小时会对覆盖海洋环境中预期CO₂浓度范围的4组CO₂标准气体进行分析，以此校准气体分析仪。标准气体浓度采用WMO-X2007空气CO₂摩尔分数标尺。标准气体测量完成后，通过船舶前桅杆的进气口抽取外部洁净空气，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艏部约5.5米水深处。CO₂系统旁配备赛默百德（Seabird Electronics）SBE21型热盐仪（thermosalinograph），用于测量海表盐度；取水口处安装有赛默百德SBE 38型远程温度传感器，用于测量海表温度（SST）。取水口至CO₂系统的输水耗时通常约4分钟，输水过程中水温升高一般低于0.6℃。热盐仪的供水同样取自该取水口，但输水管道在取水口后即与CO₂系统的输水管道分离。对比热盐仪与平衡舱的温度记录可知，两条输水管道的水温差通常小于0.1℃；热盐仪输水管道沿船舶外部布设，其水温通常高于平衡舱输水管道。热盐仪输水管道的输水耗时比平衡舱管道快2.5分钟。气象数据、盐度、海表温度、船舶位置与时间信息均取自船舶日志系统。上述参数及数据质量由澳大利亚国家海洋设施（Australian Marine National Facility）负责维护。