IMOS - Ships of Opportunity - Ocean Carbon Dioxide Data from RV Southern Surveyor voyage SS042009

This data was collected in September 2009 by the IMOS Ship of Opportunity Underway CO2 Measurement research group on RV Southern Surveyor (IMOS platform code: VLHJ) voyage SS042009.Departed:     Hobart, Tasmania, September 22, 2009Arrived:     Hobart, Tasmania, September 30, 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（Integrated Marine Observing System, IMOS）的船舶走航式CO₂测量研究小组，于2009年9月在"RV Southern Surveyor"（IMOS平台代码：VLHJ）的SS042009航次中采集。
起航：塔斯马尼亚州霍巴特，2009年9月22日
抵达：塔斯马尼亚州霍巴特，2009年9月30日

CO₂系统概述：表层海水二氧化碳分压（fCO₂）采用通用海洋学公司（General Oceanics Inc.）的自动化系统（型号8050；Pierrot等，2009）进行测定。具体流程为：将海水喷入平衡舱，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，经纳菲隆干燥管干燥后，通入Licor 7000型非色散红外气体分析仪，以测定干燥空气的CO₂摩尔分数（XCO₂）。CO₂测量过程中会暂时中断气流，所有测量均在大气压下完成。每间隔约4小时，即分析一组覆盖海洋环境预期CO₂浓度范围的4种标准CO₂气体，用于校准气体分析仪。标准气体的浓度基于WMO-X2007空气CO₂摩尔分数标尺标定。完成标准气体分析后，通过船舶前桅的进气口抽取洁净室外空气，用以测定大气干燥态XCO₂。

海水采样及辅助数据：海水采样口位于船舶船首约5.5米水深处。紧邻CO₂系统安装的热敏盐度计（Seabird Electronics SBE21）用于测定海表盐度；采样口处搭载的远程温度传感器（Seabird Electronics SBE 38）用于测定海表温度（SST）。采样口至CO₂系统的输水时长通常约为4分钟，输水过程中海水的温升通常小于0.6℃。热敏盐度计的供水同样取自该采样口，但两条输水管道在采样口处分流。对热敏盐度计与平衡舱的温度记录进行比对后发现，两条管道内的水温差通常小于0.1℃；由于热敏盐度计的输水管道沿船舶外部铺设，其水温通常高于平衡舱输水管道。输水至热敏盐度计的时长比至平衡舱快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管控工作由澳大利亚海洋国家设施（Australian Marine National Facility）负责。