IMOS - SOOP 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.\n\nDeparted: Sydney, Australia, January 22, 2010\nArrived: \t Hobart, Australia, February 15, 2010\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）的“机会船舶走航CO₂测量”研究小组，于2010年1月至2月在“南方探索者号（RV Southern Surveyor，IMOS平台代码：VLHJ）”的SS012010航次中采集。

起航地：澳大利亚悉尼，2010年1月22日
抵达地：澳大利亚霍巴特，2010年2月15日

## CO₂系统概述
表层海水二氧化碳分压（fugacity of carbon dioxide, fCO₂）采用General Oceanics公司（General Oceanics Inc.）生产的自动化测量系统（型号8050；参照Pierrot等2009年的研究方法）进行测定。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通过热电冷凝器（thermoelectric condenser）、纳菲恩干燥管（nafion drying tube）处理，再输送至Licor 7000型非分散红外气体分析仪（Licor 7000 non-dispersive infrared gas analyser），以测量干燥空气中的CO₂摩尔分数（XCO₂）。CO₂测量环节会临时中断气流，且全程在大气压下开展。每间隔约4小时，便会使用一套覆盖海洋典型CO₂浓度范围的4种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CO₂摩尔分数标度。完成标准气体校准后，通过船舶前桅的进气口抽取洁净室外空气，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。紧邻CO₂测量系统安装的是西贝德电子公司（Seabird Electronics）生产的SBE21型热盐计（thermosalinograph），用于测定海表盐度；取水口处布设的西贝德电子公司（Seabird Electronics）生产的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，其间水温升高幅度通常小于0.6℃。热盐计的取水水源与CO₂系统同源，但输水管道在取水口后即发生分支。对比热盐计与平衡舱的温度记录可知，两条输水管道的温差通常小于0.1℃；热盐计输水管道沿船舶外壁铺设，水温通常高于平衡舱输水管道，且其输水耗时比平衡舱管道短2.5分钟。

气象数据、盐度、海表温度、船舶位置及时间参数均取自船舶日志系统，相关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。