IMOS - SOOP Ocean Carbon Dioxide Data from RV Southern Surveyor voyage SS062010 (Fremantle-Fremantle)

This data was collected in July and August 2010 by the IMOS Ship of Opportunity Underway CO2 Measurement research group on RV Southern Surveyor (IMOS platform code: VLHJ) voyage SS062010.

Departed: Fremantle Australia, July 29, 2010
Arrived: Fremantle, Australia, August 9, 2010

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IMOS船舶随行走航CO₂测量研究小组于2010年7月至8月间，在“南方考察号”（RV Southern Surveyor，IMOS平台代码：VLHJ）航次SS062010上采集完成。
起航：澳大利亚弗里曼特尔，2010年7月29日
抵达：澳大利亚弗里曼特尔，2010年8月9日

CO₂系统概述：
表层海水二氧化碳逸度（fCO₂，fugacity of carbon dioxide）采用通用海洋学公司（General Oceanics Inc.）的自动化测量系统（型号8050；Pierrot等，2009）进行检测。具体流程为：将海水喷入平衡气室，顶空气体中的CO₂与海水完成气液平衡。顶空气体经热电冷凝器、纳菲恩干燥管后，通入Licor 7000型非分散红外气体分析仪，以测量干燥空气的CO₂摩尔分数（XCO₂）。CO₂测量环节会暂时中断气流，且所有测量均在大气压条件下开展。每间隔约4小时，即分析一组覆盖海洋环境预期CO₂浓度范围的4种CO₂标准气，用于校准气体分析仪。标准气浓度采用WMO-X2007空气CO₂摩尔分数量表定值。完成标准气测量后，通过船舶前桅杆的进气口抽取外部清洁空气，用于测量大气干燥态XCO₂。

海水取水及辅助数据：
海水取水口位于船艏约5.5米水深位置。紧邻CO₂系统的热敏盐度计（thermosalinograph，Sea-Bird Electronics SBE21）用于测量海表盐度。布设于取水口处的远程温度传感器（Sea-Bird Electronics SBE 38）用于测量海表温度（SST，Sea Surface Temperature）。取水口至CO₂系统的输水时长通常约4分钟，沿途水温升高幅度一般小于0.6℃。热敏盐度计的取水同样源自该取水口，但输水管道在取水后即发生分支。对比热敏盐度计与平衡器的温度记录可知，两条输水管道的温差通常小于0.1℃。热敏盐度计的输水管道沿船体外侧布设，其温度通常高于平衡器输水管道。热敏盐度计的输水耗时比平衡器少2.5分钟。

气象数据、盐度、SST、船舶位置及时间数据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。