IMOS - Ships of Opportunity - Ocean Carbon Dioxide Data from MV L'Astrolabe voyage AL1213R2 (Dumont d'Urville station - Hobart)

This data was collected in January 2013 by the IMOS Ship of Opportunity Underway CO2 Measurement research group on MV L'Astrolabe (IMOS platform code: FHZI) voyage AL1213R2.Departed: Dumont d'Urville station, Antarctica, January 26, 2012Arrived: Hobart Australia, January 31, 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 (Table 1) that cover the range of CO2 values expected in the ocean are analysed about every three hours to calibrate the gas analyser. Atmospheric XCO2 (dry) is measured after the standards by pumping clean outside air from an intake on the forward mast of the ship. The seawater intake is at about 3m depth in the bow of the ship. A remote temperature sensor (Seabird Electronics SBE38) located at the intake is used to measure sea surface temperature (SST). Sea surface salinity is measured using a thermosalinograph (Seabird Electronics SBE21) mounted in the bow thruster space near the intake. The travel time between the intake and CO2 system is typically about 50 seconds with warming usually less than 0.4ºC. The thermosalinograph water is from the same intake and supply line. Meteorological data, salinity, SST, and ships position and time are taken from the ship’s logging system. The salinity values measured by the SBE21 were checked against discrete bottle samples collected on the voyage.Meteorological data, salinity, SST, and ships position and time are taken from the ships logging system.

本数据集由IMOS机会船航行中CO₂测量研究小组于2013年1月在‘阿斯特罗 labe’号（MV L'Astrolabe，IMOS平台代码：FHZI）AL1213R2航次期间采集。
出发地：南极洲杜蒙·德乌尔维尔站，2012年1月26日
到达地：澳大利亚霍巴特，2012年1月31日

CO₂系统概述：
海水表层的二氧化碳逸度（fugacity of carbon dioxide，fCO₂）采用General Oceanics Inc.的自动化系统（型号8050；Pierrot等人，2009）进行测量。海水被喷入平衡室（equilibration chamber），顶空气体中的CO₂与海水达到平衡。顶空气体经热电冷凝器（thermoelectric condenser）和Nafion干燥管处理后，流入Licor 7000非分散红外气体分析仪，用于测量干燥空气中的CO₂摩尔分数（CO₂ mole fraction，XCO₂）。在大气压下进行CO₂测量时，气流会暂时中断。每隔约3小时分析一组涵盖海洋预期CO₂值范围的4个CO₂标准气（表1），以校准气体分析仪。标准气分析后，通过抽取船首桅杆进气口的洁净外部空气，测量干燥大气中的XCO₂。

海水取水口位于船首约3米深度处。取水口处安装有远程温度传感器（Seabird Electronics SBE38），用于测量海表温度（sea surface temperature，SST）。海表盐度采用安装在取水口附近船首推进器舱内的温盐深仪（thermosalinograph，Seabird Electronics SBE21）测量。取水口到CO₂系统的水流传输时间通常约为50秒，水温升高一般不超过0.4℃。温盐深仪的水样来自同一取水口和供水管道。气象数据、盐度、SST、船位和时间均取自船舶日志系统。SBE21测量的盐度值通过与航次中采集的离散瓶样进行比对验证。

气象数据、盐度、SST、船位和时间均取自船舶日志系统。