IMOS - SOOP Ocean Carbon Dioxide Data from MV L'Astrolabe voyage AL1011R4 (Hobart-Dumont d'Urville station)

This data was collected in February 2011 by the IMOS Ship of Opportunity Underway CO2 Measurement research group on MV L'Astrolabe (IMOS platform code: FHZI) voyage AL1011R4.

Departed: Hobart Australia, February 20, 2011
Arrived: Dumont d'Urville station, Antarctica, February 26, 2011

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 (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.

本数据集于2011年2月由综合海洋观测系统（Integrated Marine Observing System，IMOS）的机遇船走航CO₂测量研究小组在MV“星盘号”（IMOS平台代码：FHZI）的AL1011R4航次中采集。
起航地：澳大利亚霍巴特，2011年2月20日
抵达地：南极迪蒙·迪尔维尔站，2011年2月26日

二氧化碳测量系统概述：
海水表层二氧化碳逸度（fCO₂）采用General Oceanics Inc.自动化系统（型号8050；Pierrot等，2009）进行测定。将海水喷入平衡腔室，顶空气体中的二氧化碳与海水达到气液平衡。顶空气体经热电冷凝器、纳菲恩干燥管后，流入Licor 7000型非色散红外气体分析仪，以测定干燥空气中的二氧化碳摩尔分数（XCO₂）。二氧化碳测量在常压下进行，测量期间会暂时切断气流。每隔约3小时分析一组覆盖海洋预期二氧化碳浓度范围的4种二氧化碳标准气体（见表1），以此对气体分析仪进行校准。标准气体分析完成后，通过安装在船舶前桅的进气口抽取洁净外界空气，测定干燥大气中的XCO₂。

海水采样口位于船舶船首约3米水深处。安装在采样口处的远程温度传感器（SeaBird Electronics SBE38）用于测定海表温度（SST）；海表盐度通过安装在采样口附近船首推力器舱内的盐温深仪（SeaBird Electronics SBE21）测定。采样口至二氧化碳测量系统的输水时长通常约为50秒，输水过程中水温升高通常不超过0.4℃。盐温深仪的采样水源与二氧化碳测量系统取自同一采样口及供水管路。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。

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。