IMOS - SOOP Ocean Carbon Dioxide Data from RV Southern Surveyor voyage SS2011_T02 (Auckland-Hobart)

This data was collected in June 2011 by the IMOS Ship of Opportunity Underway CO2 Measurement research group on RV Southern Surveyor (IMOS platform code: VLHJ) voyage SS2011_T02.

Departed: Auckland, NZ, June 06, 2011
Arrived: Hobart, TAS, June 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.

本数据集由澳大利亚海洋综合观测系统（Integrated Marine Observing System，IMOS）机遇船舶走航CO₂测量研究组，于2011年6月在“南方探索者号”（RV Southern Surveyor，IMOS平台代码：VLHJ）的SS2011_T02航次中采集完成。

起航地点：新西兰奥克兰，2011年6月6日
抵达地点：澳大利亚塔斯马尼亚州霍巴特，2011年6月14日

CO₂系统概况：
表层海水二氧化碳逸度（fugacity of carbon dioxide，fCO₂）采用General Oceanics Inc.自动化系统（型号8050；Pierrot等，2009）进行测定。具体流程为：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；随后将顶空气体泵送至热电冷凝器，经纳菲隆干燥管除湿后，流经Licor 7000型非色散红外气体分析仪，以测定干燥空气中的二氧化碳摩尔分数（XCO₂）。测量过程中会暂时中断气流，且所有CO₂测量均在大气压力下完成。每约4小时会分析一组覆盖海洋预期CO₂浓度范围的4种标准CO₂气体，用于校准气体分析仪。标准气体浓度采用WMO-X2007空气二氧化碳摩尔分数尺度。完成标准气体校准后，通过船舶前桅杆上的进气口抽取清洁外界空气，以测定大气干燥态XCO₂。

海水采样与辅助数据：
海水采样口位于船舶船首约5.5米水深处。紧邻CO₂系统安装了Seabird Electronics SBE21型热盐深仪，用于测定海表盐度；采样口处安装了Seabird Electronics SBE 38型远程温度传感器，用于测定海表温度（sea surface temperature，SST）。从采样口至CO₂系统的输水时长通常约为4分钟，期间水温升高通常不超过0.6℃。热盐深仪的供水取自同一采样口，但输水线路在采样口后即分支。对热盐深仪与平衡腔的温度记录进行比对后发现，两条输水线路的温差通常小于0.1℃；热盐深仪的输水线路沿船舶外部铺设，通常温度高于平衡腔输水线路，且其输水时长比平衡腔线路短2.5分钟。

气象数据、盐度、海表温度、船舶位置及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。