IMOS - SOOP Ocean Carbon Dioxide Data from RV Southern Surveyor voyage SS2011_C01 (Sydney-Hobart)

This data was collected in April 2011 by the IMOS Ship of Opportunity Underway CO2 Measurement research group on RV Southern Surveyor (IMOS platform code: VLHJ) voyage SS2011_C01.

Departed: Sydney, NSW, Apr 05, 2011
Arrived: Hobart, TAS, Apr 14, 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 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.

本数据集由综合海洋观测系统（Integrated Marine Observing System，IMOS）机遇船舶走航CO₂测量研究小组，于2011年4月搭载“南方探索者号”科考船（RV Southern Surveyor，IMOS平台代码：VLHJ）执行航次SS2011_C01期间采集。

起航地点：新南威尔士州悉尼市，起航时间：2011年4月5日
抵达地点：塔斯马尼亚州霍巴特市，抵达时间：2011年4月14日

CO₂系统概述：
采用通用海洋学公司（General Oceanics Inc.）自动化系统（型号8050；Pierrot等，2009）测量表层海水二氧化碳逸度（fCO₂）。具体测量流程如下：将海水喷入平衡腔，顶空气体中的CO₂与海水实现气液平衡；随后将顶空气体泵送至热电冷凝器，再经纳菲隆干燥管除湿，之后流经Licor 7000型非色散红外气体分析仪，以测定干燥空气中的CO₂摩尔分数（XCO₂）。CO₂测量环节会暂时中断气流，且所有测定均在常压下完成。每约4小时分析一组覆盖海洋典型CO₂浓度范围的4种CO₂标准气体，用于校准气体分析仪。标准气体的浓度采用世界气象组织-X2007（WMO-X2007）空气CO₂摩尔分数标度。完成标准气体校准后，通过船艏桅杆前部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：
海水取水口位于船首约5.5米水深处。紧邻CO₂系统安装的西博德电子公司（Seabird Electronics）SBE21型热盐深仪，用于测量海面盐度。安装于取水口处的西博德电子公司（Seabird Electronics）SBE38型远程温度传感器，用于测量海面水温（SST）。取水口至CO₂系统的输水行程通常约4分钟，沿途水温升高幅度通常小于0.6℃。热盐深仪的取水水源与CO₂系统一致，但输水管道在取水口处分流。对热盐深仪与平衡腔的温度记录进行比对后发现，两条管道的水温差通常小于0.1℃。热盐深仪的输水管道沿船体外铺设，水温通常高于平衡腔输水管道。热盐深仪输水管道的行程比平衡腔输水管道短2.5分钟。

气象数据、盐度、海面水温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海洋国家设施（Australian Marine National Facility）负责维护。