IMOS - SOOP Ocean Carbon Dioxide Data from RV Southern Surveyor voyage SS092008

This data was collected in July and August 2008 by the IMOS Ship of Opportunity Underway CO2 Measurement research group on RV Southern Surveyor (IMOS platform code: VLHJ) voyage SS092008.

Departed: Cairns, Queensland, July 24, 2008
Arrived: Gladstone, Queensland, August 11, 2008

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机遇船舶走航二氧化碳测量研究组，于2008年7月至8月搭载“南部勘探者号”（RV Southern Surveyor，IMOS平台代码：VLHJ）执行航次SS092008期间采集。

本航次启航与抵达信息：2008年7月24日从昆士兰州凯恩斯港出发，2008年8月11日抵达昆士兰州格拉德斯通港。

## 二氧化碳测量系统概况
表层海水二氧化碳逸度（fCO2）采用通用海洋仪器公司（General Oceanics Inc.）8050型自动化系统开展测定（Pierrot等，2009）。测定流程如下：将海水喷入平衡室，顶空气体中的二氧化碳与海水完成气液平衡；随后将顶空气体依次经热电冷凝器、纳菲恩干燥管除湿，再通入Licor 7000型非色散红外气体分析仪，以测定干燥空气的二氧化碳摩尔分数（XCO2）。测量过程中临时中断气流，且在常压下完成检测。每约4小时使用一套覆盖海洋典型二氧化碳浓度范围的4种标准二氧化碳气体对气体分析仪进行校准，标准气体的浓度基准为WMO-X2007空气二氧化碳摩尔分数尺度。标准气体测量结束后，通过船舶前桅杆的进气口抽取外部清洁空气，以测定大气干燥态XCO2。

## 海水取水与辅助数据
海水取水口位于船艏约5.5米水深处。紧邻二氧化碳测量系统安装有斯贝尔德电子（Seabird Electronics）SBE21型温盐计，用于监测海表盐度；取水口处布设斯贝尔德电子SBE38型远程温度传感器，用于测量海表水温（SST）。取水口至二氧化碳测量系统的输水时长通常约4分钟，期间水体升温幅度一般小于0.6℃。温盐计的供水同样取自该取水口，但供水管路在取水口后即发生分支。对温盐计与平衡器的温度记录进行比对可知，两条管路的水温差通常小于0.1℃；温盐计供水管路沿船体外部铺设，水温普遍高于平衡器管路，且其输水时长较平衡器管路短2.5分钟。

本航次的气象数据、盐度、海表水温、船舶位置与时间信息均取自船舶日志系统，相关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。