IMOS - SOOP Ocean Carbon Dioxide Data from RV Southern Surveyor voyage SS2012_V02 (Fiji-Fiji)

This data was collected from May to June 2012 by the IMOS Ship of Opportunity Underway CO2 Measurement research group on RV Southern Surveyor (IMOS platform code: VLHJ) voyage SS2012_V02.

Departed: Lautoka, Fiji, May 11, 2012
Arrived: Lautoka, Fiji, June 04, 2012

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.

本数据集由澳大利亚海洋综合观测系统（Integrated Marine Observing System, IMOS）的“机会船舶走航CO₂测量”研究小组，于2012年5月至6月期间，在RV Southern Surveyor科考船（IMOS平台代码：VLHJ）的SS2012_V02航次中采集。

起航：斐济劳托卡，2012年5月11日
抵达：斐济劳托卡，2012年6月4日

CO₂系统概述：
本研究采用通用海洋仪器公司（General Oceanics Inc.）生产的自动化系统（型号8050；参考Pierrot等2009年研究），对表层海水二氧化碳逸度（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。随后将顶空气体泵送至热电冷凝器（thermoelectric condenser），再经纳菲恩干燥管（nafion drying tube）除湿，随后流经Licor 7000型非色散红外气体分析仪（non-dispersive infrared gas analyser），以测定干燥空气中的CO₂摩尔分数（XCO₂）。CO₂测量过程中会暂时切断气流，且所有测量均在大气压下进行。每间隔约4小时，会使用一组覆盖海洋中预期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世界气象组织WMO-X2007空气中CO₂摩尔分数标度。在完成标准气体校准后，通过船舶前桅杆上的进气口抽取外部洁净空气，以测定大气干燥态XCO₂。

海水取水口与辅助数据：
海水取水口位于船艏约5.5米水深处。紧邻CO₂系统安装的热盐深仪（thermosalinograph，Sea-Bird Electronics SBE21）用于测定海表盐度。取水口处安装的远程温度传感器（Sea-Bird Electronics SBE 38）用于测量海表温度（Sea Surface Temperature, SST）。取水口至CO₂系统的输水行程通常约为4分钟，且输水过程中的水温升高通常小于0.6℃。热盐深仪的取水水源与CO₂系统取自同一取水口，但输水管道在取水口后分支。对热盐深仪与平衡腔的温度记录进行比对后发现，两条输水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，通常比平衡腔的输水管道水温更高。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、海表温度、船舶位置与时间数据均来自船舶日志系统。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。