IMOS - SOOP Ocean Carbon Dioxide Data from RV Southern Surveyor voyage ST012009

This data was collected in January 2009 by the IMOS Ship of Opportunity Underway CO2 Measurement research group on RV Southern Surveyor (IMOS platform code: VLHJ) voyage ST012009.

Departed: Sydney, New South Wales, January 25, 2009
Arrived: Wellington, New Zealand, February 1, 2009

CO2 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.

本数据集由海洋综合观测系统（Integrated Marine Observing System，IMOS）的机会船走航CO₂测量研究小组，于2009年1月在“南方调查者号”（RV Southern Surveyor，IMOS平台代码：VLHJ）的ST012009航次中采集。

起航地：澳大利亚新南威尔士州悉尼，2009年1月25日
抵达地：新西兰惠灵顿，2009年2月1日

CO₂系统概述：
本研究采用通用海洋学公司（General Oceanics Inc.）生产的自动化系统（型号8050；参考Pierrot等2009年研究），对表层海水的二氧化碳分压（fugacity of carbon dioxide, fCO₂）进行测定。具体流程为：将海水喷入平衡腔，使顶空气体中的CO₂与海水达到气液平衡；随后将顶空气体经热电冷凝器、纳菲隆干燥管（nafion drying tube）泵送，再通过Licor 7000型非色散红外气体分析仪，测量干燥空气的CO₂摩尔分数（XCO₂）。测量过程中会临时暂停气流，且所有测定均在大气压条件下完成。每间隔约4小时，会使用一套覆盖海洋环境中预期CO₂浓度范围的4种CO₂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CO₂摩尔分数标度。完成标准气体校准后，通过安装在船舶前桅的进气口抽取洁净外界空气，以测量大气干燥态XCO₂。

海水取水口与辅助数据：
海水取水口位于船舶船首约5.5米水深处。CO₂系统旁配备了一台热盐仪（Seabird Electronics SBE21），用于测量海表盐度。取水口处安装有远程温度传感器（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为4分钟，且输水过程中水温升高一般不超过0.6℃。热盐仪的取水水源与CO₂系统一致，但输水管道在取水口处分流。对热盐仪与平衡腔的温度记录进行对比后发现，两条输水管道间的温差通常小于0.1℃。热盐仪的输水管道沿船舶外部铺设，因此水温通常高于平衡腔的输水管道。热盐仪输水管道的输水时长比平衡腔短2.5分钟。

气象数据、盐度、海表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。