IMOS - SOOP Ocean Carbon Dioxide Data from RV Southern Surveyor voyage SS032008

This data was collected in February and March 2008 by the IMOS Ship of Opportunity Underway CO2 Measurement research group on RV Southern Surveyor (IMOS platform code: VLHJ) voyage SS032008.\n\nDeparted: \tPort Adelaide, South Australia, February 28, 2008\nArrived: \tHobart, Tasmania, March 17, 2008\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.

本数据集由海洋仪器与观测系统（IMOS）机遇船舶走航CO₂测量研究小组，于2008年2至3月搭载“南方考察号”（RV Southern Surveyor，IMOS平台代码：VLHJ）执行航次SS032008期间采集。

启航：2008年2月28日，澳大利亚南澳州阿德莱德港
抵港：2008年3月17日，塔斯马尼亚州霍巴特港

CO₂系统概述：
本研究采用通用海洋设备公司（General Oceanics Inc.）生产的自动化系统（型号8050；Pierrot等，2009），对表层海水的二氧化碳逸度（fCO₂）进行测量。将海水喷入平衡舱，使顶空气体中的二氧化碳与海水达到气液平衡。将顶空气体泵送至热电冷凝器，随后经纳菲昂干燥管干燥，再通入LI-7000型非色散红外气体分析仪，以测量干燥空气的二氧化碳摩尔分数（XCO₂）。测量二氧化碳时会暂时切断气流，所有测量均在大气压下完成。每约4小时便会对一组涵盖海洋环境中预期二氧化碳浓度范围的4种二氧化碳标准气体进行分析，以校准气体分析仪。标准气体的浓度采用WMO-X2007空气中二氧化碳摩尔分数标度。完成标准气体分析后，通过抽取船舶前桅进气口处的洁净室外空气，测量干燥大气中的XCO₂。

海水取样及辅助数据：
海水取样口位于船舶船首约5.5米水深处。采用安装于CO₂系统旁的热盐计（SeaBird Electronics SBE21）测量海面盐度。在取样口处安装远程温度传感器（SeaBird Electronics SBE 38），以测量海面温度（SST）。从取样口至CO₂系统的输水行程通常约为4分钟，期间水体升温幅度一般低于0.6℃。热盐计的取水水源与本系统一致，但输水管道在取样口处分流。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低于0.1℃。热盐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内的水温。热盐计输水管道的行程时长较平衡舱输水管道短2.5分钟。

气象数据、盐度、海面温度以及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。